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Posts Tagged ‘AML’


miRNA Therapeutic Promise

Curator: Larry H. Bernstein, MD, FCAP

 

MicroRNA Expression Could Be Key to Leukemia Treatment

http://www.genengnews.com/gen-news-highlights/microrna-expression-could-be-key-to-leukemia-treatment/81252662/

MicroRNA Expression Could Be Key to Leukemia Treatment

Generalized gene regulation mechanisms of miRNAs. [NIH]

 

Increasingly, cancer researchers are discovering novel biological pathways that regulate the expression of various genes that are often strongly associated with tumorigenesis. These new molecular mechanisms represent important potential therapeutic targets for aggressive and difficult-to-treat cancers. In particular, microRNAs (miRNAs)—small, noncoding genetic material that regulates gene expression—have steadily become implicated in the progression of some cancers.

Now, researchers at the University of Cincinnati (UC) have found a particular signaling route for a microRNA, miR-22, that they believe leads to targets for acute myeloid leukemia (AML), the most common type of fast-growing cancer of the blood and bone marrow.

The findings from this study were published recently in Nature Communications in an article entitled “miR-22 Has a Potent Anti-Tumour Role with Therapeutic Potential in Acute Myeloid Leukaemia.”

Structure of mi-22 miccroRNA. [Ppgardne at el., via Wikimedia Commons]

Increasingly, cancer researchers are discovering novel biological pathways that regulate the expression of various genes that are often strongly associated with tumorigenesis. These new molecular mechanisms represent important potential therapeutic targets for aggressive and difficult-to-treat cancers. In particular, microRNAs (miRNAs)—small, noncoding genetic material that regulates gene expression—have steadily become implicated in the progression of some cancers.

Now, researchers at the University of Cincinnati (UC) have found a particular signaling route for a microRNA, miR-22, that they believe leads to targets for acute myeloid leukemia (AML), the most common type of fast-growing cancer of the blood and bone marrow.

The findings from this study were published recently in Nature Communications in an article entitled “miR-22 Has a Potent Anti-Tumour Role with Therapeutic Potential in Acute Myeloid Leukaemia.”

“MicroRNAs make up a class of small, noncoding internal RNAs that control a gene’s job, or expression, by directing their target messaging RNAs, or mRNAs, to inhibit or stop. Cellular organisms use mRNA to convey genetic information,” explained senior study author Jianjun Chen, Ph.D., associate professor in the department of cancer biology at the UC College of Medicine. “Previous research has shown that microRNA miR-22 is linked to breast cancer and other blood disorders which sometimes turn into AML, but we found in this study that it could be an essential anti-tumor gatekeeper in AML when it is down-regulated, meaning its function is minimized.”

AML—most common type of acute leukemia—arises when the bone marrow begins to make blasts, cells that have not yet completely matured. These blast cells typically develop into white blood cells; however, in AML the cells do not develop and are unable to aid in warding off infections. In the current study, the UC team describes how altering the expression of miR-22 affected AML pathogenesis.

“When we forced miR-22 expression, we saw difficulty in leukemia cells developing, growing, and thriving. miR-22 targets multiple cancer-causing genes (CRTC1, FLT3, and MYCBP) and blocks certain pathways (CREB and MYC),” Dr. Chen noted. “The downregulation, or decreased output, of miR-22 in AML, is caused by the loss of the number of DNA being copied and/or stopping their expression through a pathway called TET1/GFI1/EZH2/SIN3A. Also, nanoparticles carrying miR-22 DNA oligonucleotides (short nucleic acid molecules) prevented leukemia advancement.”

The investigators conducted the study using bone marrow transplant samples and animal models. The researchers showed that the ten-eleven translocation proteins (TET1/2/3) in mammals helped to control genetic expression in normal developmental processes. This was in sharp contrast to mutations that cause function loss and tumor-slowing with TET2, which has been observed previously in blood and stem cell cancers.

“We recently reported that TET1 plays an essential cancer generating role in certain AML where it activates expression of homeobox genes, which are a large family of similar genes that direct the formation of many body structures during early embryonic development,” remarked Dr. Chen. “However, it is unknown whether TET1 can also function as a repressor for cellular function in cancer, and its role in microRNA expression has rarely been studied.”

Dr. Chen added that these findings are important in targeting a cancer that is both common and fatal, stating that “the majority of patients with ALM usually don’t survive longer than 5 years, even with chemotherapy, which is why the development of new effective therapies based on the underlying mechanisms of the disease is so important.”

“Our study uncovers a previously unappreciated signaling pathway (TET1/GFI1/EZH2/SIN3A/miR-22/CREB-MYC) and provides new insights into genetic mechanisms causing and progressing AML and also highlights the clinical potential of miR-22-based AML therapy. More research on this pathway and ways to target it are necessary,” Dr. Chen concluded.

 

miR-22 has a potent anti-tumour role with therapeutic potential in acute myeloid leukaemia

Xi JiangChao HuStephen ArnovitzJason BugnoMiao YuZhixiang ZuoPing Chen, et al.
Nature Communications 26 Apr 2016; 7(11452).    http://dx.doi.org:/doi:10.1038/ncomms11452

MicroRNAs are subject to precise regulation and have key roles in tumorigenesis. In contrast to the oncogenic role of miR-22 reported in myelodysplastic syndrome (MDS) and breast cancer, here we show that miR-22 is an essential anti-tumour gatekeeper in de novo acute myeloid leukaemia (AML) where it is significantly downregulated. Forced expression of miR-22 significantly suppresses leukaemic cell viability and growth in vitro, and substantially inhibits leukaemia development and maintenance in vivo. Mechanistically, miR-22 targets multiple oncogenes, including CRTC1, FLT3 and MYCBP, and thus represses the CREB and MYC pathways. The downregulation of miR-22 in AML is caused by TET1/GFI1/EZH2/SIN3A-mediated epigenetic repression and/or DNA copy-number loss. Furthermore, nanoparticles carrying miR-22 oligos significantly inhibit leukaemia progression in vivo. Together, our study uncovers a TET1/GFI1/EZH2/SIN3A/miR-22/CREB-MYC signalling circuit and thereby provides insights into epigenetic/genetic mechanisms underlying the pathogenesis of AML, and also highlights the clinical potential of miR-22-based AML therapy.

 

As one of the most common and fatal forms of hematopoietic malignancies, acute myeloid leukaemia (AML) is frequently associated with diverse chromosome translocations (for example t(11q23)/MLL-rearrangements, t(15;17)/PML-RARA and t(8;21)/AML1-ETO) and molecular abnormalities (for example, internal tandem duplications of FLT3 (FLT3-ITD) and mutations in nucleophosmin (NPM1c+))1. Despite intensive chemotherapies, the majority of patients with AML fail to survive longer than 5 years2, 3. Thus, development of effective therapeutic strategies based on a better understanding of the molecular mechanisms underlying the pathogenesis of AML is urgently needed.

MicroRNAs (miRNAs) are a class of small, non-coding RNAs that post-transcriptionally regulate gene expression4. Individual miRNAs may play distinct roles in cancers originating from different tissues or even from different lineages of hematopoietic cells4. It is unclear whether a single miRNA can play distinct roles between malignancies originating from the same hematopoietic lineage, such as de novo AML and myelodysplastic syndrome (MDS). Although around 30% of MDS cases transform to AML, the genetic and epigenetic landscapes of MDS or MDS-derived AML are largely different from those of de novo AML5, 6. MDS and MDS-derived AML are more responsive to hypomethylating agents than de novo AML7. The molecular mechanisms underlying the distinct pathogenesis and drug response between MDS (or MDS-derived AML) and de novo AML remain unclear.

The ten-eleven translocation (Tet1/2/3) proteins play critical transcriptional regulatory roles in normal developmental processes as activators or repressors8, 9, 10. In contrast to the frequent loss-of-function mutations and tumour-suppressor role of TET2 observed in hematopoietic malignancies11, 12, 13, we recently reported that TET1 plays an essential oncogenic role in MLL-rearranged AML where it activates expression of homeobox genes14. However, it is unknown whether TET1 can also function as a transcriptional repressor in cancer. Moreover, Tet1-mediated regulation of miRNA expression has rarely been studied10.

In the present study, we demonstrate that miR-22, an oncogenic miRNA reported in breast cancer and MDS15, 16, is significantly downregulated in most cases of de novo AML due to TET1/GFI1/EZH2/SIN3A-mediated epigenetic repression and/or DNA copy-number loss. miR-22 functions as an essential anti-tumour gatekeeper in various AML and holds great therapeutic potential to treat AML.

 

The downregulation of miR-22 in de novo AML

Through Exiqon miRNA array profiling, we previously identified a set of miRNAs, such as miR-150, miR-148a, miR-29a, miR-29b, miR-184, miR-342, miR-423 and miR-22, which are significantly downregulated in AML compared with normal controls17. Here we showed that among all the above miRNAs, miR-150 and especially miR-22 exhibited the most significant and consistent inhibitory effect on MLL-AF9-induced cell immortalization in colony-forming/replating assays (CFA) (Supplementary Fig. 1a). In contrast to the reported upregulation of miR-22 in MDS16, our original microarray data17 (Fig. 1a,b) and new quantitative PCR-independent validation data (Supplementary Fig. 1b) demonstrated a significant and global downregulation of miR-22 in de novo AML relative to normal controls. Notably, miR-22 is significantly downregulated in AML samples (P<0.05) compared with all three sub-populations of normal control cells, that is, normal CD34+ hematopoietic stem/progenitor cells (HSPCs), CD33+ myeloid progenitor cells, or mononuclear cells (MNCs) (Fig. 1a). Expression of miR-22 is significantly downregulated in all or the majority of individual subsets of AML samples than in the normal CD33+ or CD34+ cell samples (Fig. 1b).

Figure 1: miR-22 inhibits AML cell transformation and leukemogenesis.

miR-22 inhibits AML cell transformation and leukemogenesis.

(a,b) Exiqon microRNA profiling assay showed that miR-22 is significantly (P<0.05) downregulated in the entire set of AML set (n=85) (a) or each individual subset (b), relative to normal controls. The expression data were log(2) transformed and mean-centred. Mean±s.e.m. values were shown. (c) Comparison of effects of in-house miR-22, miR-22_Song16 and miR-22 mutant (miR-22mut; see the mutation sequence at the top) on MLL-AF9-induced colony forming. CFAs were performed using mouse BM progenitor (Lin) cells transduced with MSCV-neo+MSCV-PIG (Ctrl), MSCV-neo-MLL-AF9+MSCV-PIG (MLL-AF9), or MSCV-neo-MLL-AF9+MSCV-PIG-miR-22/miR-22_Song/miR-22mut. (d) Effects of miR-22 on the colony forming induced by multiple fusion genes. CFA was performed using wild-type BM progenitor cells co-transduced with MSCV-neo-MLL-AF9 (MA9), -MLL-AF10 (MA10), -PML-RARA (PR) or –AML1-ETO9a(AE9a)19, together with MSCV-PIG (Ctrl) or MSCV-PIG-miR-22 (+miR-22), as well as miR-22−/− BM progenitors co-transduced with individual fusion genes and MSCV-PIG. Colony counts (mean±s.d.) of the second round of plating are shown. *P<0.05; **P<0.01. (e,f) Effect of miR-22 on MLL-AF9-induced primary leukemogenesis. Kaplan–Meier curves are shown for six cohorts of transplanted mice including MSCVneo+MSCV-PIG (Ctrl; n=5), MSCVneo+MSCV-PIG-miR-22 (miR-22; n=5), MSCVneo-MLL-AF9+MSCV-PIG (MA9; n=8), MSCVneo-MLL-AF9+MSCV-PIG-miR-150 (MA9+miR-150, n=6), MSCVneo-MLL-AF9+MSCV-PIG-miR-22 (MA9+miR-22; n=10) and MSCVneo-MLL-AF9+MSCV-PIG-miR-22mutant (MA9+miR-22mut; n=5) (e); Wright–Giemsa stained PB and bone marrow (BM), and hematoxylin and eosin (H&E) stained spleen and liver of the primary BMT recipient mice at the end point are shown (f). (g) Effect of miR-22 on MLL-AF10-induced primary leukemogenesis. Kaplan–Meier curves are shown for two cohorts of transplanted mice including MSCVneo-MLL-AF10+MSCV-PIG (MA10; n=5) and MSCVneo-MLL-AF10+MSCV-PIG-miR-22 (MA10+miR-22; n=5). (h) miR-22 knockout promotes AE9a-induced leukemogenesis. Kaplan–Meier curves are shown for mice transplanted with wild-type or miR-22−/− BM progenitor cells transduced MSCV-PIG-AE9a (n=5 for each group). The P values were generated by t-test (ad) or log-rank test (e,g,h).

To rule out the possibility that the inhibitory effect of miR-22 shown in Supplementary Fig. 1a was due to a non-specific effect of our miR-22 construct, we included the MSCV-PIG-miR-22 construct from Song et al.16 in a repeated CFA. Both miR-22 constructs dramatically inhibited MLL-AF9-induced colony formation (Fig. 1c). As the ‘seed’ sequences at the 5′ end of individual miRNAs are essential for the miRNA-target binding18, we also mutated the 6-bases ‘seed’ sequence of miR-22 and found that the miR-22 mutant did not inhibit colony formation anymore (Fig. 1c). In human AML cells, forced expression of miR-22, but not miR-22 mutant, significantly inhibited cell viability and growth/proliferation, while promoting apoptosis (Supplementary Fig. 1c,d).

Furthermore, as miR-22 is globally downregulated in all major types of AML (Fig. 1b), we also investigated the role of miR-22 in colony formation induced by other oncogenic fusion genes, including MLL-AF10/t(10;11), PML-RARA/t(15;17) and AML1-ETO9a/t(8;21) (ref. 19). As expected, forced expression of miR-22 significantly inhibited colony formation induced by all individual oncogenic fusions; conversely, miR-22 knockout20 significantly enhanced colony forming (Fig. 1d). These results suggest that miR-22 likely plays a broad anti-tumour role in AML.

In accordance with the potential anti-tumour function of miR-22 in AML, miR-22 was expressed at a significantly higher level (P<0.05) in human normal CD33+ myeloid progenitor cells than in more immature CD34+ HSPCs or MNC cells (a mixed population containing both primitive progenitors and committed cells) (Fig. 1a,b), implying that miR-22 is upregulated during normal myelopoiesis. Similarly, we showed that miR-22 was also expressed at a significantly higher level in mouse normal bone marrow (BM) myeloid (Gr-1+/Mac-1+) cells, relative to lineage negative (Lin) progenitor cells, long-term hematopoietic stem cells (LT-HSCs), short-term HSCs (ST-HSCs), and committed progenitors (CPs) (Supplementary Fig. 1e), further suggesting that miR-22 is upregulated in normal myelopoiesis.

The anti-tumour effect of miR-22 in the pathogenesis of AML

Through bone marrow transplantation (BMT) assays, we showed that forced expression of miR-22 (but not miR-22 mutant) dramatically blocked MLL-AF9 (MA9)-mediated leukemogenesis in primary BMT recipient mice, with a more potent inhibitory effect than miR-150 (Fig. 1e;Supplementary Fig. 2a). All MA9+miR-22 mice exhibited normal morphologies in peripheral blood (PB), BM, spleen and liver tissues (Fig. 1f), with a substantially reduced c-Kit+ blast cell population in BM (Supplementary Fig. 2b). Forced expression of miR-22 also almost completely inhibited leukemogenesis induced by MLL-AF10 (Fig. 1g; Supplementary Fig. 2a). Conversely, miR-22 knockout significantly promoted AML1-ETO9a (AE9a)-induced AML (Fig. 1h). Thus, the repression of miR-22 is critical for the development of primary AML. Notably, forced expression of miR-22 inMLL-AF9 and MLL-AF10 leukaemia mouse models caused only a 2–3-fold increase in miR-22 expression level (Supplementary Fig. 2a), in a degree comparable to the difference in miR-22 expression levels between human AML samples and normal controls (Fig. 1a), suggesting that a 2–3-fold change in miR-22 expression level appears to be able to exert significant physiological or pathological effects.

To examine whether the maintenance of AML is also dependent on the repression of miR-22, we performed secondary BMT assays. Forced expression of miR-22 remarkably inhibited progression of MLL-AF9-, AE9a– or FLT3-ITD/NPM1c+-induced AML in secondary recipient mice (Fig. 2a–d), resulting in largely normal morphologies in PB, BM, spleen and liver tissues (Fig. 2b;Supplementary Fig. 2c). Collectively, our findings demonstrate that miR-22 is a pivotal anti-tumour gatekeeper in both development and maintenance of various AML.

Figure 2: Effect of miR-22 on the maintenance of AML in vivo.

Effect of miR-22 on the maintenance of AML in vivo.

(a,b) Effect of miR-22 on the maintenance of MLL-AF9-induced AML in secondary BMT recipient mice. The secondary BMT recipients were transplanted with BM blast cells from the primary MLL-AF9 AML mice retrovirally transduced with MSCV-PIG+MSCVneo (MA9-AML+Ctrl; n=7) or MSCV-PIG+MSCVneo-miR-22 (MA9-AML+miR-22; n=10). Kaplan–Meier curves (a) and Wright–Giemsa or H&E-stained PB, BM, spleen and liver (b) of the secondary leukaemic mice are shown. (c,d) Effect of miR-22 on the maintenance/progression of AML1-ETO9a (AE9a)-induced AML (c) or FLT3-ITD/NPM1c+-induced AML (d) in secondary BMT recipient mice (n=5 for each group). Kaplan–Meier curves and P values (log-rank test) are shown.

 

Identification of critical target genes of miR-22 in AML

To identify potential targets of miR-22 in AML, we performed a series of data analysis. Analysis of In-house_81S (ref. 21) and TCGA_177S (ref. 22) data sets revealed a total of 999 genes exhibiting significant inverse correlations with miR-22 in expression. Of them, 137 genes, including 21 potential targets of miR-22 as predicted by TargetScan18 (Supplementary Table 1), were significantly upregulated in both human and mouse AML compared with normal controls as detected in two additional in-house data sets14, 23. Among the 21 potential targets, CRTC1, ETV6and FLT3 are known oncogenes24, 25, 26, 27, 28, 29. We then focused on these three genes, along with MYCBP that encodes the MYC-binding protein and is an experimentally validated target of miR-22 (ref. 30) although due to a technical issue it was not shown in the 21-gene list (Supplementary Table 1), for further studies.

As expected, all four genes were significantly downregulated in expression by ectopic expression of miR-22 in human MONOMAC-6/t(9;11) cells (Fig. 3a). The coincidence of downregulation of those genes and upregulation of miR-22 was also observed in mouse MLL-ENL-ERtm cells, a leukaemic cell line with an inducible MLL-ENL derivative31, when MLL-ENL was depleted by 4-hydroxy-tamoxifen (4-OHT) withdrawal (Fig. 3b; Supplementary Fig. 3a). While MLL-AF9 remarkably promoted expression of those four genes in mouse BM progenitor cells, co-expressed miR-22 reversed the upregulation (Fig. 3c). In leukaemia BM blast cells of mice with MLL-AF9-induced AML, the expression of Crtc1, Flt3 and Mycbp, but not Etv6, was significantly downregulated by co-expressed miR-22 (but not by miR-22 mutant) (Fig. 3d). Because miR-22-mediated downregulation of Etv6 could be observed only in the in vitro models (Fig. 3a–c), but not in the in vivo model (Fig. 3d), which was probably due to the difference between in vitro and in vivo microenvironments, we decided to focus on the three target genes (that is, Crtc1, Flt3 and Mycbp) that showed consistent patterns between in vitro and in vivo for further studies. The repression of Crtc1, Flt3 and Mycbpwas also found in leukaemia BM cells of mice with AE9a or FLT3-ITD/NPM1c+-induced AML (Fig. 3e,f). As Mycbp is already a known target of miR-22 (ref. 30), here we further confirmed that FLT3and CRTC1 are also direct targets of miR-22 (Fig. 3g,h). The downregulation of CRTC1, FLT3 and MYCBP by miR-22 at the protein level was confirmed in both human and mouse leukaemic cells (Supplementary Fig. 3b,c). Overexpression of miR-22 had no significant influence on the level of leukaemia fusion genes (Supplementary Fig. 3d).

Figure 3: miR-22 targets multiple oncogenes.

miR-22 targets multiple oncogenes.

(a) Downregulation of CRTC1, FLT3, MYCBP and ETV6 by forced expression of miR-22 in MONOMAC-6 cells. Expression of these genes was detected 48h post transfection of MSCV-PIG (Ctrl) or MSCV-PIG-miR-22 (miR-22). (b) Crtc1, Flt3, Mycbp and Etv6 levels in MLL-ENL-ERtm cells after withdrawal of 4-OHT for 0, 7 or 10 days. (c) Expression levels of Crtc1, Flt3, Mycbp and Etv6 in mouse BM progenitor cells retrovirally transduced with MSCV-PIG+MSCV-neo (Ctrl), MSCV-PIG-miR-22+MSCV-neo (miR-22), MSCV-PIG+MSCV-neo-MLL-AF9 (MLL-AF9) or MSCV-PIG-miR-22+MSCV-neo-MLL-AF9 (MLL-AF9+miR-22). (d) Expression levels of Crtc1, Flt3, Mycbp and Etv6 in BM blast cells of leukaemic mice transplanted with MLL-AF9, MLL-AF9+miR-22 or MLL-AF9+miR-22mut primary leukaemic cells. (e,f) Expression levels of Crtc1, Flt3 and Mycbp in BM blast cells of leukaemic mice transplanted with MSCV-PIG or MSCV-PIG-miR-22-retrovirally transduced AE9a (e) or FLT3-ITD/NPM1c+ (f) primary leukaemic cells. (g) Putative miR-22 target sites and mutants in the 3′UTRs of CRTC1 (upper panel) and FLT3(lower panel). (h) Effects of miR-22 on luciferase activity of the reporter gene bearing wild type or mutant 3′UTRs of CRTC1 or FLT3 in HEK293T cells. The mean±s.d. values from three replicates are shown.*P<0.05, t-test.

Co-expression of the coding region (CDS) of each of the three target genes (that is, CRTC1, FLT3and MYCBP) largely reversed the effects of miR-22 on cell viability, apoptosis and proliferation (Fig. 4a–e). More importantly, in vivo BMT assays showed that co-expressing CRTC1, FLT3 orMYCBP largely rescued the inhibitory effect of miR-22 on leukemogenesis (Fig. 4f,g;Supplementary Fig. 3e). Our data thus suggest that CRTC1, FLT3 and MYCBP are functionally important targets of miR-22 in AML.

Figure 4: Multiple onocgenes are functionally important targets of miR-22 in AML.

Multiple onocgenes are functionally important targets of miR-22 in AML.

(a,b) Relative viability (a) and apoptosis (b) levels of MONOMAC-6 cells transfected with MSCV-PIG-CRTC1, -FLT3 or –MYCBP alone, or together with MSCVneo-miR-22. Values were detected 48h post transfection. (c–e) Rescue effects of CRTC1 (c), FLT3 (d) and MYCBP (e) on the inhibition of MONOMAC-6 growth mediated by miR-22. Cell counts at the indicated time points are shown. Mean±s.d. values are shown. *P<0.05, t-test. (f) In vivo rescue effects of CRTC1, FLT3 and MYCBP on the inhibition of MLL-AF9-induced leukemogenesis mediated by miR-22. The secondary recipients were transplanted with BM blast cells of the primary MLL-AF9 leukaemic mice retrovirally transduced with MSCVneo+MSCV-PIG (MA9-AML+Ctrl; n=7), MSCVneo-miR-22+MSCV-PIG (MA9-AML+miR-22; n=10), MSCVneo-miR-22+MSCV-PIG-CRTC1 (MA9-AML+miR-22+CRTC1; n=5), MSCVneo-miR-22+MSCV-PIG-FLT3 (MA9-AML+miR-22+FLT3; n=6) or MSCVneo-miR-22+MSCV-PIG-MYCBP (MA9-AML+miR-22+MYCBP; n=6). Kaplan–Meier curves for all the five groups of transplanted mice are shown. MA9-AML+Ctrl versus MA9-AML+miR-22, P<0.001 (log-rank test); MA9-AML+Ctrl versus any other groups,P>0.05 (log-rank test). (g) Wright–Giemsa stained PB and BM, and H&E stained spleen and liver of the secondary leukaemic mice.

miR-22 represses both CREB and MYC signalling pathways

DNA copy-number loss of miR-22 gene locus in AML

Expression of miR-22 is epigenetically repressed in AML

 

Figure 5: Transcriptional correlation between miR-22 and TET1.

(a) Correlation between the expression levels of miR-22 and TET1 in three independent AML patient databases. All expression data were log(2) transformed; the data in In-house_81S were also mean-centred. The correlation coefficient (r) and P values were detected by ‘Pearson Correlation’, and the correlation regression lines were drawn with the ‘linear regression’ algorithm. (b) Expression of pri-, pre- and mature miR-22, and Tet1/2/3 in colony-forming cells of wild-type mouse BM progenitors retrovirally transduced with MSCVneo (Ctrl), MSCVneo-MLL-AF9 (MLL-AF9), MSCVneo-MLL-AF10 (MLL-AF10) or MSCVneo-AE9a (AE9a), or of FLT3-ITD/NPM1c+ mouse BM progenitors transduced with MSCVneo (FLT3-ITD+/NPM1c+). (c) Expression of miR-22 and Tet1/2/3 in MLL-ENL-ERtm cells. Expression levels were detected at the indicated time points post 4-OHT withdrawal. (d) Effect of miR-22 overexpression onTet1 expression in colony-forming cells with MLL-AF9, AE9a or FLT3-ITD/NPM1c+. (e) Expression ofTet1 in BM progenitor cells of 6-weeks old miR-22−/− or wild-type mice. (f) Effect of miR-22 overexpression on TET1 expression in THP-1 and KOCL-48 AML cells 48h post transfection. (g) Expression of pri-, pre- and mature miR-22 in BM progenitor cells of 6-weeks old Tet1−/− or wild-type mice. Mean±s.d. values are shown. *P<0.05, t-test.

(a) Tet1 targets miR-22 promoter region (−1,100/+55bp), as detected by luciferase reporter assay 48h post transfection in HEK293T cells. (b) Expression of TET1/2/3, EZH2, SIN3A, GFI1 and miR-22 in THP-1 cells 72h post treatment with 1μM ATRA or DMSO control. (c) Co-immunoprecipitation assay showing the binding of endogenous GFI1 and TET1 in THP1 cells. (d) ChIP-qPCR analyses of the promoter region of miR-22 in THP-1 cells 72h post treatment with 1μM ATRA or DMSO. Upper panel: PCR site on the CpG-enriched region of miR-22 gene locus. Note: miR-22 is coded within the second exon of a long non-coding RNA (MIR22HG), which represents the primary transcript of miR-22. Lower panels: enrichment of MLL-N terminal (for both wild-type MLL and MLL-fusion proteins), MLL-C terminal (for wild-type MLL), TET1, EZH2, SIN3A, GFI1, H3K27me3, H3K4me3 or RNA pol II at miR-22 promoter region. (e) Expression levels of TET1, EZH2, SIN3A and miR-22 in GFI1 knockdown cells. (f) ChIP-qPCR analyses of the promoter region of miR-22 in THP-1 cells transduced with GFI1 shRNA or control shRNA. Enrichment of GFI1, TET1, EZH2 and SIN3A are shown. (g) Effects of knockdown of TET1, EZH2 and/orSIN3A on miR-22 expression. The expression level of miR-22 was detected in THP-1 cells 72h post transfection with siRNAs targeting TET1, EZH2 and/or SIN3A. Mean±s.d. values are shown. *P<0.05;**P<0.01 (t-test). (h) Schematic model of the regulatory pathway involving miR-22 in AML and ATRA treatment.

 

The miR-22-associated regulatory circuit in AML

         Restoration of miR-22 expression and function to treat AML

 

Figure 7: Therapeutic effect of miR-22-nanoparticles in treating AML.

(a,b) Primary leukaemia BM cells bearing MLL-AF9 (a) or AE9a (b) were transplanted into sublethally irradiated secondary recipient mice. After the onset of secondary AML (usually 10 days post transplantation), the recipient mice were treated with PBS control, or 0.5mgkg−1 miR-22 or miR-22 mutant RNA oligos formulated with G7 PAMAM dendrimer nanoparticles, i.v., every other day, until the PBS-treated control group all died of leukaemia. (c) NSGS mice49 were transplanted with MV4;11/t(4;11) AML cells. Five days post transplantation, these mice started to be treated with PBS control, miR-22 or miR-22 mutant nanoparticles at the same dose as described above. Kaplan–Meier curves are shown; the drug administration period and frequency were indicated with yellow arrows. The P values were detected by log-rank test. (d) Wright–Giemsa stained PB and BM, and H&E stained spleen and liver of the MLL-AF9-secondary leukaemic mice treated with PBS control, miR-22 or miR-22 mutant nanoparticles.

We then tested the miR-22 nanoparticles in a xeno-transplantation model49. Similarly, the nanoparticles carrying miR-22 oligos, but not miR-22 mutant, significantly delayed AML progression induced by human MV4;11/t(4;11) cells (Fig. 7c). The miR-22-nanoparticle administration also resulted in less aggressive leukaemic pathological phenotypes in the recipient mice (Supplementary Fig. 6e). Thus, our studies demonstrated the therapeutic potential of using miR-22-based nanoparticles to treat AML.

 

It remains poorly understood how TET proteins mediate gene regulation in cancer. Here we show that in de novo AML, it is TET1, but not TET2 (a reported direct target of miR-22 in MDS and breast cancer15, 16), that inversely correlates with miR-22 in expression and negatively regulates miR-22 at the transcriptional level. Likely together with GFI1, TET1 recruits polycomb cofactors (for example, EZH2/SIN3A) to the miR-22 promoter, leading to a significant increase in H3K27me3 occupancy and decrease in RNA pol II occupancy at that region, and thereby resulting in miR-22 repression in AML cells; such a repression can be abrogated by ATRA treatment. Thus, our study uncovers a novel epigenetic regulation mechanism in leukaemia involving the cooperation between TET1/GFI1 and polycomb factors.

Besides GFI1, it was reported that LSD1 is also a binding partner of TET1 (ref. 50). Interestingly, LSD1 is known as a common binding partner shared by TET1 and GFI1, and mediates the effect of GFI1 on hematopoietic differentiation51, 52. Thus, it is possible that LSD1 might also participate in the transcriptional repression of miR-22 as a component of the GFI1/TET1 repression complex.

We previously reported that TET1 cooperates with MLL fusions in positively regulating their oncogenic co-targets in MLL-rearranged AML14. Here we show that TET1 can also function as a transcriptional repressor (of a miRNA) in cancer. The requirement of TET1-mediated regulation on expression of its positive (for example, HOXA/MEIS1/PBX3)14 or negative (for example, miR-22) downstream effectors in leukemogenesis likely explains the rareness of TET1 mutations in AML53, and highlights its potent oncogenic role in leukaemia.

The aberrant activation of both CREB and MYC signalling pathways has been shown in AML24, 25,26, 54, 55, but the underlying molecular mechanisms remain elusive. Our data suggest that the activation of these two signalling pathways in AML can be attributed, at least in part, to the repression of miR-22, which in turn, results in the de-repression of CRTC1 (CREB pathway), FLT3and MYCBP (MYC pathway), and leads to the upregulation of oncogenic downstream targets (for example, CDK6, HOXA7, BMI1, FASN and HMGA1) and downregulation of tumour-suppressor downstream targets (for example, RGS2).

In summary, we uncover a TET1/GFI1/EZH2/SIN3A⊣miR-22⊣CREB-MYC signalling circuit in de novo AML, in which miR-22 functions as a pivotal anti-tumour gate-keeper, distinct from its oncogenic role reported in MDS or MDS-derived AML16. Thus, our study together with the study of Song et al.16 highlight the complexity and functional importance of miR-22-associated gene regulation and signalling pathways in hematopoietic malignancies, and may provide novel insights into the genetic/epigenetic differences between de novo AML and MDS.

Our findings also highlight the possibility of using miR-22-based therapy to treat AML patients. Our proof-of-concept studies demonstrate that the nanoparticles carrying miR-22 oligos significantly inhibit AML progression and prolong survival of leukaemic mice in both BMT and xeno-transplantation models. Notably, miRNA-based nanoparticles have already entered clinical trials56. It would be important, in the future, to further test the combination of miR-22-carrying nanoparticles (or small-molecule compounds that can induce endogenous expression of miR-22) with standard chemotherapy agents (cytosine arabinoside and anthracycline), or with the emerging small molecule inhibitors against MYC and/or CREB pathway effectors, to achieve optimal anti-leukaemia effect with minimal side effects. Overall, our results suggest that restoration of miR-22 expression/function (for example, using miR-22-carrying nanoparticles or small-molecule compounds) holds great therapeutic potential to treat AML, especially those resistant to current therapies.

 

MicroRNAs: A Gene Silencing Mechanism with Therapeutic Implications  

Wed, July 13, 2016   The New York Academy of Sciences    Presented by the Biochemical Pharmacology Discussion Group
http://www.nyas.org/Events/Detail.aspx?cid=787a5d77-8354-4df7-92d5-91db18b2ce49

MicroRNAs (miRNAs) are single-stranded RNAs about 22 nucleotides in length that repress the expression of specific proteins by annealing to complementary sequences in the 3′ untranslated regions (UTRs) of target mRNAs. Apart from their posttranscriptional expression, or silencing, miRNAs may also direct mRNA destabilization and cleavage. Moreover, rather than targeting a single disease-associated protein target as many small molecule drugs and antibodies do, each miRNA may serve to repress the expression of numerous proteins involved in the pathogenesis and progression of various diseases and could therefore potentially interfere with multiple disease-promoting signal transduction pathways. Because aberrant expression of miRNAs has been implicated in numerous disease states, miRNA-based therapies have sparked much interest for the treatment of a variety of diseases. The objective of this symposium is to bring together investigators who have led the field in describing what miRNAs do and their potential in treating diseases, as well as those who are translating these findings into promising drug candidates, some of which have already advanced into early stage clinical trials.

Call for Poster Abstracts

Abstract submissions are invited for a poster session. For complete submission instructions, please send an email to miRNA@nyas.org with the words “Abstract Information” in the subject line. The deadline for abstract submission is May 13, 2016.

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Chemotherapy in AML

Curator: Larry H. Bernstein, MD, FCAP

 

 

Sorafenib Showed Efficacy as Chemotherapy Add-On in AML
Results from the phase II SORAML trial indicated that adding sorafenib to standard chemotherapy for younger patients with acute myeloid leukemia was effective, but also resulted in increased toxicity

Reduced-Intensity HSCT Extends Remission in Older AML Patients
The use of reduced-intensity conditioning HSCT as a method to maintain remission was effective in a select group of older patients with acute myeloid leukemia

 

Sorafenib Showed Efficacy as Chemotherapy Add-On in AML

– See more at: http://www.cancernetwork.com/leukemia-lymphoma/sorafenib-showed-efficacy-chemotherapy-add-aml

 

Results from the phase II SORAML trial indicated that adding sorafenib to standard chemotherapy for younger patients with acute myeloid leukemia (AML) was effective, but also resulted in increased toxicity.

 

The drug increased event-free survival and reduced need for salvage therapy and allogeneic stem cell transplantation, but also produced worse grade 3 or higher fever, diarrhea, bleeding, cardiac events, and rash compared with placebo.

“After a decade of assessing the potential of kinase inhibitors in acute myeloid leukemia, their use in combination with standard treatment is becoming an important option for newly diagnosed younger patients,” wrote Christoph Röllig, MD, of Medizinische Klinik und Poliklinik I, Universitätsklinikum der Technischen Universität in Dresden, Germany, and colleagues in Lancet Oncology.

Patients age 18 to 60 years were enrolled in the phase II study between 2009 and 2011. All patients had to have newly diagnosed, treatment-naive AML and a performance status of 0–2. Patients were randomly assigned to 2 cycles of induction daunorubicin plus cytarabine followed by 3 cycles of high-dose cytarabine consolidation therapy plus either sorafenib 400 mg twice daily (n = 134) or placebo (n = 133).

With a median follow-up of 3 years, the researchers found that adding sorafenib to standard chemotherapy significantly improved event-free survival, from a median of 9 months with placebo to a median of 21 months with sorafenib. Patients assigned sorafenib had a 3-year event-free survival rate of 40% compared with 22% for patients assigned placebo (P = .013).

“The improvement in event-free survival and relapse-free survival is significant and clinically relevant since salvage treatment with or without allogeneic stem cell transplantation could be prevented or substantially delayed by sorafenib treatment,” the researchers wrote.

At 3 years, 63% of patients assigned sorafenib and 56% of patients assigned placebo were still alive, and the median overall survival was not reached in either group. Patients assigned sorafenib had fewer relapses after complete remission compared with placebo (54 vs 34) and, therefore, fewer allogeneic stem cell transplantations were required among patients assigned sorafenib (31 vs 18).

Finally, withdrawal from the trial due to adverse events was more common among patients assigned sorafenib (24% vs 12%).

In an editorial published with the study, Naval Daver, MD, and Marina Konopleva, MD, PhD, of the University of Texas MD Anderson Cancer Center in Houston, pointed out that these results contrast findings by Serve et al who found that “the addition of sorafenib to standard chemotherapy in patients older than 60 years with acute myeloid leukemia resulted in increased toxicity and early mortality,” without improved antileukemic efficacy compared with placebo, suggesting that older patients were unable to tolerate the toxicities associated with the addition of sorafenib to standard chemotherapy.

Daver and Konopleva agreed with Röllig and colleagues, writing that the lack of improvement in overall survival despite an improvement in event-free survival requires “further investigation to develop future strategies that will improve overall survival.”

 

Sorafenib and novel multikinase inhibitors in AML

Naval Daver, Marina Konopleva

The Lancet Oncology 2015.          DOI: http://dx.doi.org/10.1016/S1470-2045(15)00454-4

Induction chemotherapy can produce complete remission in most (50–70%) patients with acute myeloid leukaemia.1 However, between 50% and 80% of patients relapse, and only 20–30% achieve long-term disease-free survival.

 

Reduced-Intensity HSCT Extends Remission in Older AML Patients

– See more at: http://www.cancernetwork.com/leukemia-lymphoma/reduced-intensity-hsct-extends-remission-older-aml-patients

 

The use of reduced-intensity conditioning hematopoietic stem cell transplantation (HSCT) as a method to maintain remission was effective in a select group of older patients with acute myeloid leukemia (AML), resulting in a nonrelapse mortality (NRM) similar to that seen in younger patients, according to the results of the phase II Cancer and Leukemia Group B 100103/Blood and Marrow Transplant Clinical Trial Network 0502 trial. 

 

“Of critical importance, for the first time (to the best of our knowledge), favorable results in transplantation of older patients have been obtained in a multicenter cooperative group setting, which makes the results more likely to be generalizable,” wrote Steven M. Devine, MD, of the Ohio State University in Columbus, Ohio, and colleagues in the Journal of Clinical Oncology.

According to the study, although patients aged older than 60 have complete remission rates of 50% to 60%, many will ultimately relapse. HSCT is associated with lower rates of relapse compared with chemotherapy in younger patients, but has been considered too toxic for older patients.

This study looked at the use of reduced-intensity conditioning HSCT in an older patient population aged 60 to 74 years. It included 114 patients with AML who were in first complete remission. The median age of patients was 65 years. A little more than half of the patients received transplants from unrelated donors and were given rabbit antithymocyte globulin (ATG) for graft-versus-host disease (GVHD) prophylaxis.

At follow-up, 71 patients had died. The median follow-up of the 43 surviving patients was 1,602 days. At 2 years, the rate of disease-free survival (DFS) was 42% and overall survival (OS) was 48%. Among patients who had unrelated donors, the 2-year DFS was 40% and the OS was 50%.

“The 2-year DFS and OS rates in this group compare favorably to those in studies of conventional chemotherapy–based approaches to remission consolidation in which DFS and OS rates beyond 2 years are typically below 20%,” the researchers wrote.

The NRM at 2 years was 15% and was not different among those patients with related vs unrelated donors. Forty-four percent of patients relapsed at 2 years.

“The 44% relapse rate at 2 years was high, although relapse rates approaching 80% to 90% have been observed in older patients after conventional chemotherapy, suggesting a potential graft-versus-leukemia effect,” the researchers wrote. “Interpretation of our trial results is limited somewhat by lack of consistent knowledge of the mutational status of the patients at diagnosis or of disease burden at complete remission by minimal residual disease assessment.”

There was a cumulative incidence of grades 2 to 4 GVHD of 9.6% and of grade 3 to 4 GVHD of 2.6% at 100 days. The incidence of GVHD did not vary by donor type. Chronic GVHD occurred in 28% of patients.

Devine and colleagues noted that these rates were lower than they anticipated.

“The incorporation of rabbit ATG into the conditioning regimen for all patients, including recipients with matched sibling donors, may have contributed to the relatively low rates of GVHD and NRM, as has been observed in previous studies,” they wrote.

 

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Myelodysplastic syndrome and acute myeloid leukemia following adjuvant chemotherapy

Larry H. Bernstein, MD, FCAP, Curator

LPBI

Myelodysplastic syndrome and acute myeloid leukemia following adjuvant chemotherapy with and without granulocyte colony stimulating factors for breast cancer

Gregory S. Calip1,2,3 • Judith A. Malmgren3,4 • Wan-Ju Lee1 • Stephen M. Schwartz2,3 • Henry G. Kaplan5

See discussions, stats, and author profiles for this publication at: http://www.researchgate.net/publication/282702665

Breast Cancer Res Treat   OCTOBER 2015        http://dx.doi.org:/10.1007/s10549-015-3590-1

https://www.researchgate.net/profile/Gregory_Calip/publication/282702665_Myelodysplastic_syndrome_and_acute_myeloid_leukemia_following_adjuvant_chemotherapy_with_and_without_granulocyte_colony-stimulating_factors_for_breast_cancer/links/56193f6a08ae78721f9cff46.pdf

Abstract Risk of myelodysplastic syndrome (MDS) and acute myeloid leukemia (AML) post-breast cancer treatment with adjuvant chemotherapy and granulocyte colonystimulating factors (G-CSF) is not fully characterized. Our objective was to estimate MDS/AML risk associated with specific breast cancer treatments. We conducted a retrospective cohort study of women aged C66 years with stage I–III breast cancer between 2001 and 2009 using the Surveillance, Epidemiology, and End Results-Medicare database. Women were classified as receiving treatment with radiation, chemotherapy, and/or G-CSF. We used multivariable Cox proportional hazards models to estimate adjusted hazard ratios (HR) and 95 % confidence intervals (CI) for MDS/AML risk. Among 56,251 breast cancer cases, 1.2 % developed MDS/AML during median followup of 3.2 years. 47.1 % of women received radiation and 14.3 % received chemotherapy. Compared to breast cancer cases treated with surgery alone, those treated with chemotherapy (HR = 1.38, 95 %-CI 0.98–1.93) and chemotherapy/radiation (HR = 1.77, 95 %-CI 1.25–2.51) had increased risk of MDS/AML, but not radiation alone (HR = 1.08, 95 % CI 0.86–1.36). Among chemotherapy regimens and G-CSF, MDS/AML risk was differentially associated with anthracycline/cyclophosphamide-containing regimens (HR = 1.86, 95 %-CI 1.33–2.61) and filgrastim (HR = 1.47, 95 %-CI 1.05–2.06), but not pegfilgrastim (HR = 1.10, 95 %-CI 0.73–1.66). We observed increased MDS/AML risk among older breast cancer survivors treated with anthracycline/cyclophosphamide chemotherapy that was enhanced by G-CSF. Although small, this risk warrants consideration when determining adjuvant chemotherapy and neutropenia prophylaxis for breast cancer patients.

Keywords Breast cancer, Myelodysplastic syndrome, Acute myeloid leukemia, Adjuvant chemotherapy, Granulocyte colony-stimulating factors

Electronic supplementary material The online version of this article (http://dx.doi.org:/10.1007/s10549-015-3590-1) contains supplementary material, which is available to authorized users.

Introduction Myelodysplastic syndrome (MDS) and acute myeloid leukemia (AML) following cancer treatment with cytotoxic therapy with radiation and chemotherapy account for approximately 10–20 % of all cases of MDS/AML [1]. The clinical course of these cases is typically aggressive with worse prognostic features and survival compared to de novo MDS/AML [2]. Given the growing population of breast cancer survivors successfully treated with radiation and chemotherapy, uncommon but lethal iatrogenic MDS and AML (MDS/AML) are important concerns for oncologists and their patients [3].

Several studies report increased risk of MDS/AML in breast cancer patients after treatment with radiation and adjuvant chemotherapy [4–8]. For some commonly used classes of breast cancer chemotherapy agents such as alkylating agents (i.e., cyclophosphamide) and anthracyclines (i.e., doxorubicin and epirubicin), an increased incidence of treatment-related leukemia with multiple signature chromosomal abnormalities has been observed [9, 10].

Another possible association with increased MDS/AML risk in breast cancer patients has been reported for granulocyte colony-stimulating factors (G-CSF) as prophylactic treatment following adjuvant chemotherapy [11–13]. G-CSF stimulates proliferation and differentiation of white blood cells and is used to prevent chemotherapy-induced neutropenia [14–17]. While G-CSF reduces the need for treatment delays or dose reductions, the anti-apoptotic effects of G-CSF could potentially spare some lineagespecific mutant stem cells resulting from cytotoxic therapy and permit survival in subsets of mature myeloid cells with chromosomal alterations [18]. Prior population-based studies of G-CSF use with adjuvant chemotherapy and MDS/AML risk among older women in the Surveillance, Epidemiology, and End Results (SEER)-Medicare linked database show mixed results with increased risk of MDS/ AML reported in one study [12] and no association with risk of AML in another [4]. In the Cancer and Leukemia Group B 9741 phase III trial [19], patients randomized to dose-dense chemotherapy with filgrastim support had no increased risk of developing MDS/AML, but in a review of randomized clinical trials by Lyman et al. [13], chemotherapy patients treated with G-CSF had a doubling in risk of MDS/AML post-treatment.

Secondary treatment-related myeloid cancers are rare, and the overall number of cases following breast cancer is low. However, consideration of MDS/AML risk postbreast cancer treatment may be important for subgroups of patients susceptible due to age [20] and/or use of potentially leukemogenic therapies [21]. Our purpose is to evaluate current MDS/AML risk among women treated for invasive breast cancer in the SEER-Medicare linked database between 2001 and 2009, a period in which MDS became a reportable disease, new treatment regimens became standard and use of G-CSF increased [14, 15, 22].

Methods: see http://dx.doi.org:/10.1007/s10549-015-3590-1

Study population

Data sources

Exposures

Outcomes

Statistical analysis

Results Characteristics of the 56,251 incident stage I–III breast cancer patients included in our study are shown in Table 1. Median age was 75 years at breast cancer diagnosis and most were Non-Hispanic White (87 %) with Charlson comorbidity scores C1 (84 %).

The majority of incident breast cancer was stage I (57 %) or stage II (34 %), lymph nodenegative (74 %), estrogen/progesterone receptor positive (79 %), and treated with breast-conserving surgery (59 %). The majority of breast cancer patients were treated with surgery only (46 %), with 40 % receiving surgery/radiation, 7 % surgery/chemotherapy and 7 % surgery/radiation/chemotherapy (Table 1).

Table 1 (not shown) Descriptive characteristics of female Medicare beneficiaries diagnosed with incident stage I–III breast cancer between 2001 and 2009 by subsequent primary MDS/AML status

No MDS/AML (n = 55,596)    MDS/AML (n = 655)   P value    All women (N = 56,251)

Age (years) at breast cancer diagnosis Median (interquartile range)

Race

Hispanic ethnicity

AJCC Stage

Lymph node status

Hormone receptor status

Charlson comorbidity index

Surgical procedure

Combined radiation and chemotherapy

Chemotherapy type

Granulocyte colony-stimulating factors

Number of G-CSF doses

Person-years of follow-up
Median (interquartile range)
————————————–

MDS myelodysplastic syndrome, AML acute myeloid leukemia
a To test for differences of characteristics between the 2 groups, we used v2 test for categorical variables and Wilcoxon rank-sum test for medians
b Other ethnicity includes Asian/Pacific Islander, American Indian, and Alaskan Native
c Chemotherapy agents: A anthracyclines (doxorubicin or epirubicin); C cyclophosphamide; T taxanes (docetaxel or paclitaxel); F fluorouracil; M methotrexate; chemotherapy regimens listed are mutually exclusive groups with or without trastuzumab; AC-containing regimens = AC, ACT, FAC
d Other/non-standard = single-agent therapy or one of the regimens listed above and vinca alkaloids (vincristine, vinorelbine, or vinblastine), etoposide, bevacizumab, or azacitidine together or in combination
e Use of G-CSF products not mutually exclusive

Table 2 MDS/AML cases and use of G-CSF products among female Medicare beneficiaries diagnosed with incident stage I–III breast cancer between 2001 and 2009 by chemotherapy regimena

Any chemotherapy regimen, n = 8050 All AC-containing regimensb, n = 3686 (45.8 %) TC, n = 1491 (18.5 %) CF or CMF, n = 1086 (13.5 %) Otherc, n = 1787 (22.2 %)
MDS/AMS cases 176 (2.2) 94 (2.6) 18 (1.2) 27 (2.5), 37 (2.1)
Any G-CSFd 4835 (60.1) 2552 (69.2) 1137 (76.3) 422 (38.9) 756 (42.3)
Filgrastim 1865 (23.2) 1025 (27.8) 276 (18.5) 263 (24.2) 301 (16.8)
Pegfilgrastim 3554 (44.1) 1865 (50.6) 960 (64.4) 192 (17.7) 537 (30.1)

a Chemotherapy agents: A anthracyclines (doxorubicin or epirubicin); C cyclophosphamide; T taxanes (docetaxel or paclitaxel); F fluorouracil; M methotrexate; chemotherapy regimens listed are mutually exclusive groups with or without trastuzumab
b AC-containing regimens = AC, ACT, FAC
c Other/non-standard = single-agent therapy or one of the regimens listed above and vinca alkaloids (vincristine, vinorelbine, or vinblastine), etoposide, bevacizumab, or azacitidine together or in combination
d Use of G-CSF products not mutually exclusive

Among women receiving chemotherapy treatment, the most common regimen was anthracycline/cyclophosphamide/taxane (ACT) (28 %). Overall, 46 % of breast cancer patients receiving chemotherapy had AC-containing regimens. The remaining 56 % received taxane/cyclophosphamide (TC) (19 %), cyclophoshamide/fluorouracil ?/- methotrexate (CF or CMF) (13.5 %) and other/non-standard regimens (22 %). Other non-standard regimens were single-agent therapies or one of the other listed regimens with vinca alkaloids, etoposide, bevacizumab, or azacitidine together or in combination. Sixty percent of those treated with chemotherapy received G-CSF treatment with 23 % receiving filgrastim and 44 % receiving pegfilgrastim (Table 2). Treatment with G-CSF varied by adjuvant chemotherapy regimen with TC regimen most often accompanied by G-CSF treatment (79 %) followed by the AC regimens (69 %).

Median follow-up was 3 years (interquartile range 2–7) and varied by diagnosis date with women diagnosed during the earlier study years having the longest follow-up: median 8 years for women diagnosed in 2001–2003, 6 years for 2004–2006, and 3 years for 2007–2009. Among the women in our study, 655 (1.2 %) developed MDS/ AML (n = 515 MDS and n = 140 AML), including 38 MDS cases that were later diagnosed with AML. Age-adjusted cumulative hazards of MDS/AML are shown in Fig. 1. MDS/AML incidence varied by index breast cancer treatment; 2.4 % of women treated with surgery/radiation/chemotherapy and 1.0 % of women treated with surgery only were diagnosed with MDS/AML during follow-up. Breast cancer patients with subsequent MDS/AML diagnosis were more likely to have breast cancer that was stage II or III, lymph node-positive, ER-negative/PR-negative, higher Charlson score and treated with chemotherapy and G-CSF (Table 1).

Fig. 1 (not shown) Cumulative hazard of MDS/AML among female Medicare beneficiaries diagnosed with incident stage I–III breast cancer between 2001 and 2009 by initial breast cancer treatment

In analyses from multivariable Cox models, we observed a significant association between treatment with chemotherapy and risk of MDS/AML (Fig. 2).

Fig. 2  (not shown) Risk of MDS/AML among female Medicare beneficiaries diagnosed with incident stage I–III breast cancer between 2001 and 2009 in relation to primary breast cancer initial treatment and to chemotherapy regimen.

HR (95% CI)
Combined Radiation

and Chemotherapy

None 1.00 (reference)
Radiation only 1.08 (0.86-1.36)
Chemotherapy only 1.38 (0.98-1.93)
Radiation and Chemotherapy 1.77 (1.25-2.51)
Chemotherapy

Regimen *

No Chemotherapy 1.00 (reference)
All AC-containing

regimens **

1.86 (1.33-2.61)
AC 1.48 (0.99-2.23)
ACT 1.91 (1.29-2.84)
FAC 1.79 (0.82-3.94)
TC 1.50 (0.84-2.67)
CF or CMF 1.26 (0.83-1.95)

1HR (log scale)

Abbreviations: MDS myelodysplastic syndrome; AML acute myeloid leukemia; HR hazard ratio; CI confidence interval. Chemotherapy agents: A anthracyclines (doxorubicin or epirubicin); C cyclophosphamide; T taxanes (docetaxel or paclitaxel); F fluorouracil; M methotrexate. Note all hazard ratios are adjusted for age at diagnosis (66–70, 71–75, 76–80, 81–85, 86–95 years); diagnosis year; race (White, Black, other, unknown); Hispanic ethnicity (yes, no, unknown); AJCC stage (I, II, III); hormone receptor status (ER-positive or PR-positive, ER-negative/PR-negative, unknown); surgical procedure (mastectomy, breast-conserving surgery, surgery NOS); Charlson comorbidity index score (0, 1, 2?); any granulocyte colony-stimulating factors received (yes/no). *Hazard ratios for chemotherapy regimens (AC, ACT, FAC, TC, CF, or CMF) are from a separate model adjusted for radiation therapy (yes/no). **AC-containing regimens = AC, ACT, FAC

Compared to women who received surgery only, women who received chemotherapy (HR = 1.38, 95 % CI 0.98–1.93) and chemotherapy/radiation (HR = 1.77, 95 % CI 1.25–2.51) had increased MDS/AML risk. Risk was not significantly elevated among surgery/radiation only patients. Compared to women not treated with chemotherapy, women who received anthracycline/cyclophosphamide-containing regimens had higher risk of MDS/AML (HR = 1.86, 95 % CI 1.33–2.61). Patients in the other adjuvant chemotherapy regimen categories, TC and CF/CMF, did not have significantly increased risk of MDS/AML post-treatment. G-CSF use increased over time during the study period, with use of pegfilgrastim surpassing filgrastim (Supplemental Figure S2). Adjusted for chemotherapy type, there was a non-significant increased risk of MDS/AML in women who received G-CSF with chemotherapy (HR = 1.33, 95 % CI 0.94–1.89) (Fig. 3).

No filgrastim 1.00 (reference)
Filgrastim 1.47 (1.05-2.06)
1-5 doses 1.30 (0.79-2.14)
6+ doses 1.64 (1.10-2.46)
P-trend: 0.021
No pegfilgrastim 1.00 (reference)
Pegfilgrastim 1.10 (0.73-1.66)
1-5 doses 1.04 (0.66-1.65)
6+ doses 1.30 (0.76-2.23)
P-trend: 0.845

1HR (log scale)

Fig. 3 Risk of MDS/AML among female Medicare beneficiaries diagnosed with incident stage I-III breast cancer between 2001 and 2009 that received chemotherapy in relation to G-CSF treatment. Abbreviations: MDS myelodysplastic syndrome; AML acute myeloid leukemia; HR hazard ratio; CI confidence interval; G-CSF granulocyte colony-stimulating factors. Note all hazard ratios are adjusted for age at diagnosis (66–70, 71–75, 76–80, 81–85, 86–95 years); diagnosis year; race (White, Black, other, unknown); Hispanic ethnicity (yes, no, unknown); AJCC stage (I, II, III); hormone receptor status (ER-positive or PR-positive, ER-negative/PR-negative, unknown); surgical procedure (mastectomy, breast-conserving surgery, unknown); radiation (yes/no); Charlson comorbidity index score (0, 1, 2?); chemotherapy regimen received (AC, ACT, FAC, TC, CF or CMF, other)

Stratified by G-CSF type, increased risk was observed with filgrastim use (HR = 1.47, 95 % CI 1.05–2.06) which when stratified by dosage was exclusive to the 6? dose-category (HR = 1.64, 95 % CI 1.10–2.46) (log-linear dose–response trend, P = 0.021). Pegfilgrastim use was not associated with increased MDS/AML risk with any use or in dose-stratified analyses.

In analyses of G-CSF use stratified by chemotherapy regimen, we observed a significantly increased risk of MDS/AML post-treatment among AC-containing regimens with any G-CSF treatment (n = 2552, HR = 1.78, 95 % CI 1.07–3.02) and AC-containing regimens with filgrastim treatment (n = 1025, HR = 2.01, 95 % CI 1.23–3.27) but not with pegfilgrastim treatment (n = 1865, HR = 1.20, 95 % CI 0.67–2.15) (Table 2). In additional analyses of the AC-containing regimens with filgrastim treatment by dose (1–5 doses/6+ doses), risk was increased for both categories but only significant for the 6+ filgrastim dose-category (1–5 doses: HR = 1.82, 95 % CI 0.94–3.39; 6+ doses: HR = 2.70, 95 % CI 1.33–5.28, P-trend = 0.036). No increased risk was observed among any of the other chemotherapy regimens with G-CSF treatment or with filgrastim or pegfilgrastim individually (Table 3).

Table 3 (not shown) Risk of MDS/AML in relation to G-CSF treatment among female Medicare beneficiaries diagnosed with incident stage I-III breast cancer between 2001 and 2009 by grouped chemotherapy regimens

1 G-CSF

2 Filgrastim

3 Pegfilgrastim

P-trend

AC-containing regimens

N = 3686

n = 94 MDS/AML cases

TC

N = 1491

n = 18 MDS/AML cases

CF or CMF

N = 1086

n = 27 MDS/AML cases

Chemotherapy regimen-specific hazard ratios are adjusted for age at diagnosis (66–70, 71–75, 76–80, 81–85, 86–95 years); diagnosis year;
race (White, Black, Other, unknown);
Hispanic ethnicity (yes, no, unknown);
AJCC stage (I, II, III);
hormone receptor status (ER-positive or PRpositive, ER-negative/PR-negative, unknown);
surgical procedure (mastectomy, breast-conserving surgery, unknown);
radiation (yes/no);
Charlson comorbidity score at diagnosis (0, 1, 2+)
MDS myelodysplastic syndrome,
AML acute myeloid leukemia,
HR hazard ratio,
CI confidence interval

a Chemotherapy agents: A anthracyclines (doxorubicin or epirubicin); C cyclophosphamide; T taxanes (docetaxel or paclitaxel); F fluorouracil; M methotrexate

b AC-containing regimens = AC, ACT, FAC

In sensitivity analyses, we evaluated changes in our results when criteria were varied for chemotherapy agent exposure by 1+, 2+, or 3+ HCPCS/ CPT codes, and MDS/ AML diagnoses identified from Medicare claims (1+ or 2+ ICD-9 codes). Results were not substantively different in these analyses.

Discussion In a large population-based cohort of older breast cancer patients, we found an association between chemotherapy treatment and increased risk of MDS/AML with evidence that the association may be exclusive to anthracycline/cyclophosphamide-containing regimens. In our analysis of G-CSF use by chemotherapy type and number of doses, we found increased risk of MDS/AML specific to filgrastim use and a possible dose–response effect. The MDS/AML incidence of 2.4 % among women treated with combined radiation and chemotherapy was more than double the incidence observed in women treated with surgery only and may represent a significant issue for elderly breast cancer patients. No significantly increased risk was observed among elderly patients treated with surgery and radiation only.

The absence of significant risk of MDS/AML among surgical patients treated with radiation without chemotherapy runs counter to our previous studies of MDS/AML post-treatment for breast cancer [7, 8]. However, the patients treated with chemotherapy and radiation had a higher risk than surgical patients treated with chemotherapy and no radiation. This may be due to the restriction of our observations to elderly women only in whom the risk associated with radiation may be less than that of younger women [32].

Our findings of MDS/AML risk associated with chemotherapy align with findings from previous population-based studies [4, 33] and clinical trials [5, 34]. In a prior analysis of older women using SEER-Medicare linked data (1992–2002) [4], adjuvant chemotherapy with alkylating agents and anthracyclines was associated with increased risk of AML, but MDS was not included in the analysis. The absence of association between antimetabolites (i.e., fluorouracil, methotrexate) or taxanes with risk of MDS/AML has been reported previously [4, 35–38].

Concern for leukemogenesis with the use of cytokines has existed for some time [39–43]. In a SEER-Medicare database study of breast cancer cases between 1991 and 1999 [12], increased risk of MDS/AML was observed with use of G-CSF. Another SEER-Medicare study [4] of breast cancer cases from 1992 to 2002 found no increased risk of AML with use of G-CSF in breast cancer treatment, but MDS was not included in that study. Studies in healthy stem cell donors that receive G-CSF have shown short-term induced DNA instability without increased risk of MDS/ AML [44–47]. Patients with congenital chronic neutropenia (CCN) have a high risk of leukemic transformation which may increase with long-term exposure to G-CSF [40, 41, 43]. Touw et al. hypothesized that genomic instability, including G-CSF receptor mutations, is responsible for the high rate of leukemic transformation in CCN patients treated regularly with G-CSF [42]. Slovak et al. [48] conducted a small study of clonal hematopoiesis following neoadjuvant chemotherapy for breast cancer but did not observe changes suggesting MDS/AML development. Our observation of a possible leukemogenic effect of G-CSF may represent leukemogenesis potentiation in hematopoietic cells genetically damaged by chemotherapy.

In the current study, we observed an increased risk of MDS/AML with the use of filgrastim but not pegfilgrastim. During our study period, the pegylated form of recombinant human G-CSF analog filgrastim (i.e., pegfilgrastim) was introduced. G-CSF is administered differentially with pegfilgrastim given as a fixed dose once per chemotherapy cycle and filgrastim administered daily until absolute neutrophil counts increase [14–16]. Pegfilgrastim has different pharmacokinetics than filgrastim but a similar mechanism of action [49, 50].

Strengths of this study include use of a population-based cohort from the SEER-Medicare linked database. As elderly women are rarely included in clinical trials, information on treatment risks and surveillance for rare adverse events like MDS/AML are only answered by large population-based cohort studies like ours.

A limitation of our study is the identification of subsequent diagnoses of MDS and AML based on Medicare claims and SEER data. Concerns with misclassification of MDS/AML outcomes from claims data (ICD-9 codes) are based on the tendency for false-positive MDS/AML when based on a single claim. To minimize possible misclassification, we used a recommended case definition with high specificity [31]. Using SEER as the criterion measure, ascertainment of cases using classification of two or more ICD-9 codes had sensitivity and specificity of 90.1 % and 99.2 %, respectively, for MDS; 89.3 % and 99.7 %, respectively, for AML in our study. We conducted stratified analysis to adjust for the potential confounding effect of simultaneous indication for adjuvant chemotherapy and G-CSF treatment to prevent neutropenia, both with possible leukemogenic effects. The presence of elevated risk in both the adjusted multivariable model and the stratum specific categories supports our findings.

American Society of Clinical Oncology guidelines recommend G-CSF treatment before adjuvant chemotherapy if a 20 % or greater chance of neutropenia exists [15]. Growth factor products (G-CSF) continue to be among the top 15 drug expenditures in the United States [22]. The benefits of adjuvant chemotherapy made possible with G-CSF outweigh the risk of MDS/AML in patients with high risk of breast cancer relapse [8, 17, 51–54]. It is unclear why a differential risk of MDS/AML between filgrastim and pegfilgrastim was observed. Con- firming and understanding possible differences in longterm safety of G-CSF by product are extremely important. Further studies of MDS/AML risk post-breast cancer treatment with G-CSF and adjuvant chemotherapy need to include all age groups to characterize risk attributable to specific therapies and identify patient groups that may be at greater leukemic risk.

References

1. Godley LA, Larson RA (2008) Therapy-related myeloid leukemia. Semin Oncol 35(4):418–429. doi:10.1053/j.seminoncol. 2008.04.012

2. Larson RA (2007) Etiology and management of therapy-related myeloid leukemia. Hematol Am Soc Hematol Educ Program. doi:10.1182/asheducation-2007.1.453

3. Wolff AC, Blackford AL, Visvanathan K, Rugo HS, Moy B, Goldstein LJ, Stockerl-Goldstein K, Neumayer L, Langbaum TS, Theriault RL, Hughes ME, Weeks JC, Karp JE (2015) Risk of marrow neoplasms after adjuvant breast cancer therapy: the national comprehensive cancer network experience. J Clin Oncol 33(4):340–348. doi:10.1200/JCO.2013.54.6119

4. Patt DA, Duan Z, Fang S, Hortobagyi GN, Giordano SH (2007) Acute myeloid leukemia after adjuvant breast cancer therapy in older women: understanding risk. J Clin Oncol 25(25):3871–3876. doi:10.1200/JCO.2007.12.0832

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Better Cancer Medication

Larry H. Bernstein, MD, FCAP, Curator

LPBI

A Better Class of Cancer Drugs
http://www.technologynetworks.com/medchem/news.aspx?ID=183124
An SDSU chemist has developed a technique to identify potential cancer drugs that are less likely to produce side effects.
A class of therapeutic drugs known as protein kinase inhibitors has in the past decade become a powerful weapon in the fight against various life-threatening diseases, including certain types of leukemia, lung cancer, kidney cancer and squamous cell cancer of the head and neck. One problem with these drugs, however, is that they often inhibit many different targets, which can lead to side effects and complications in therapeutic use. A recent study by San Diego State University chemist Jeffrey Gustafson has identified a new technique for improving the selectivity of these drugs and possibly decreasing unwanted side effects in the future.

Why are protein kinase–inhibiting drugs so unpredictable? The answer lies in their molecular makeup.

Many of these drug candidates possess examples of a phenomenon known as atropisomerism. To understand what this is, it’s helpful to understand a bit of the chemistry at work. Molecules can come in different forms that have exactly the same chemical formula and even the same bonds, just arranged differently. The different arrangements are mirror images of each other, with a left-handed and a right-handed arrangement. The molecules’ “handedness” is referred to as chirality. Atropisomerism is a form of chirality that arises when the spatial arrangement has a rotatable bond called an axis of chirality. Picture two non-identical paper snowflakes tethered together by a rigid stick.

Some axes of chirality are rigid, while others can freely spin about their axis. In the latter case, this means that at any given time, you could have one of two different “versions” of the same molecule.

Watershed treatment

As the name suggests, kinase inhibitors interrupt the function of kinases—a particular type of enzyme—and effectively shut down the activity of proteins that contribute to cancer.

“Kinase inhibition has been a watershed for cancer treatment,” said Gustafson, who attended SDSU as an undergraduate before earning his Ph.D. in organic chemistry from Yale University, then working there as a National Institutes of Health poctdoctoral fellow in chemical biology.

“However, it’s really hard to inhibit a single kinase,” he explained. “The majority of compounds identified inhibit not just one but many kinases, and that can lead to a number of side effects.”

Many kinase inhibitors possess axes of chirality that are freely spinning. The problem is that because you can’t control which “arrangement” of the molecule is present at a given time, the unwanted version could have unintended consequences.

In practice, this means that when medicinal chemists discover a promising kinase inhibitor that exists as two interchanging arrangements, they actually have two different inhibitors. Each one can have quite different biological effects, and it’s difficult to know which version of the molecule actually targets the right protein.

“I think this has really been under-recognized in the field,” Gustafson said. “The field needs strategies to weed out these side effects.”

Applying the brakes

So that’s what Gustafson did in a recently published study. He and his colleagues synthesized atropisomeric compounds known to target a particular family of kinases known as tyrosine kinases. To some of these compounds, the researchers added a single chlorine atom which effectively served as a brake to keep the atropisomer from spinning around, locking the molecule into either a right-handed or a left-handed version.

When the researchers screened both the modified and unmodified versions against their target kinases, they found major differences in which kinases the different versions inhibited. The unmodified compound was like a shotgun blast, inhibiting a broad range of kinases. But the locked-in right-handed and left-handed versions were choosier.

“Just by locking them into one or another atropisomeric configuration, not only were they more selective, but they  inhibited different kinases,” Gustafson explained.

If drug makers incorporated this technique into their early drug discovery process, he said, it would help identify which version of an atropisomeric compound actually targets the kinase they want to target, cutting the potential for side effects and helping to usher drugs past strict regulatory hurdles and into the hands of waiting patients.

Inroads Against Leukaemia
http://www.technologynetworks.com/medchem/news.aspx?ID=183594
Potential for halting disease in molecule isolated from sea sponges.
A molecule isolated from sea sponges and later synthesized in the lab can halt the growth of cancerous cells and could open the door to a new treatment for leukemia, according to a team of Harvard researchers and other collaborators led by Matthew Shair, a professor of chemistry and chemical biology.

“Once we learned this molecule, named cortistatin A, was very potent and selective in terms of inhibiting the growth of AML [acute myeloid leukemia] cells, we tested it in mouse models of AML and found that it was as efficacious as any other molecule we had seen, without having deleterious effects,” Shair said. “This suggests we have identified a promising new therapeutic approach.”

It’s one that could be available to test in patients relatively soon.

“We synthesized cortistatin A and we are working to develop novel therapeutics based on it by optimizing its drug-like properties,” Shair said. “Given the dearth of effective treatments for AML, we recognize the importance of advancing it toward clinical trials as quickly as possible.”

The drug-development process generally takes years, but Shair’s lab is very close to having what is known as a development candidate that could be taken into late-stage preclinical development and then clinical trials. An industrial partner will be needed to push the technology along that path and toward regulatory approval. Harvard’s Office of Technology Development (OTD) is engaged in advanced discussions to that end.

The molecule works, Shair explained, by inhibiting a pair of nearly identical kinases, called CDK8 and CDK19, that his research indicates play a key role in the growth of AML cells.

The kinases operate as part of a poorly understood, massive structure in the nucleus of cells called the mediator complex, which acts as a bridge between transcription factors and transcriptional machinery. Inhibiting these two specific kinases, Shair and colleagues found, doesn’t shut down all transcription, but instead has gene-specific effects.

“We treated AML cells with cortistatin A and measured the effects on gene expression,” Shair said. “One of the first surprises was that it’s affecting a very small number of genes — we thought it might be in the thousands, but it’s in the low hundreds.”

When Shair, Henry Pelish, a senior research associate in chemistry and chemical biology, and then-Ph.D. student Brian Liau looked closely at which genes were affected, they discovered many were associated with DNA regulatory elements known as “super-enhancers.”

“Humans have about 220 different types of cells in their body — they all have the same genome, but they have to form things like skin and bone and liver cells,” Shair explained. “In all cells, there are a relatively small number of DNA regulatory elements, called super-enhancers. These super-enhancers drive high expression of genes, many of which dictate cellular identity. A big part of cancer is a situation where that identity is lost, and the cells become poorly differentiated and are stuck in an almost stem-cell-like state.”

While a few potential cancer treatments have attacked the disease by down-regulating such cellular identity genes, Shair and colleagues were surprised to find that their molecule actually turned up the activity of those genes in AML cells.

“Before this paper, the thought was that cancer is ramping these genes up, keeping the cells in a hyper-proliferative state and affecting cell growth in that way,” Shair said. “But our molecule is saying that’s one part of the story, and in addition cancer is keeping the dosage of these genes in a narrow range. If it’s too low, the cells die. If they are pushed too high, as with cortistatin A, they return to their normal identity and stop growing.”

Shair’s lab became interested in the molecule several years ago, shortly after it was first isolated and described by other researchers. Early studies suggested it appeared to inhibit just a handful of kinases.

“We tested approximately 400 kinases, and found that it inhibits only CDK8 and CDK19 in cells, which makes it among the most selective kinase inhibitors identified to date,” Shair said. “Having compounds that precisely hit a specific target, like cortistatin A, can help reduce side effects and increase efficacy. In a way, it shatters a dogma because we thought it wasn’t possible for a molecule to be this selective and bind in a site common to all 500 human kinases, but this molecule does it, and it does it because of its 3-D structure. What’s interesting is that most kinase-inhibitor drugs do not have this type of 3-D structure. Nature is telling us that one way to achieve this level of specificity is to make molecules more like cortistatin A.”

Shair’s team successfully synthesized the molecule, which helped them study how it worked and why it affected the growth of a very specific type of cell. Later on, with funding and drug-development expertise provided by Harvard’s Blavatnik Biomedical Accelerator, Shair’s lab created a range of new molecules that may be better suited to clinical application.

“It’s a complex process to make [cortistatin A] — 32 chemical steps,” said Shair. “But we have been able to find less complex structures that act just like the natural compound, with better drug-like properties, and they can be made on a large scale and in about half as many steps.”

“Over the course of several years, we have watched this research progress from an intriguing discovery to a highly promising development candidate,” said Isaac Kohlberg, senior associate provost and chief technology development officer. “The latest results are a real testament to Matt’s ingenuity and dedication to addressing a very tough disease.”

While there is still much work to be done — in particular, to better understand how CDK8 and CDK19 regulate gene expression — the early results have been dramatic.

“This is the kind of thing you do science for,” Shair said, “the idea that once every 10 or 20 years you might find something this interesting, that sheds new light on important, difficult problems. This gives us an opportunity to generate a new understanding of cancer and also develop new therapeutics to treat it. We’re very excited and curious to see where it goes.”

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English: Cancer cells photographed by camera a...

Reported by: Dr. Venkat S. Karra, Ph.D.

Cancer remains the second leading cause of death by disease. Hundreds of new medicines to treat cancer are now being developed for lessening the burden of cancer to patients, their families and society.

Biopharmaceutical researchers are now working on 981 medicines for cancer. Many are high-tech weapons to fight the disease, while some involve innovative research into using existing medicines in new ways, the report says.

Recent developments in early detection and a steady stream of new and improved treatments suggesting that cancer is a manageable chronic disease (not a deadly one any more). Families and patients alike are with increasing expectations from the industry for more and better treatment options and America’s biopharmaceutical research companies are responding to that.

America’s biopharmaceutical research companies are working on many new cutting-edge approaches to fight cancer. They include:

• A medicine that interferes with the metabolism of cancer cells by depriving them of the energy provided by glucose.
• A medicine for acute myeloid leukemia (AML) that inhibits cancer cells with a mutation found in about a third of AML sufferers.
• A therapy that uses nanotechnology to target the delivery of medicines to cancer cells, potentially overcoming some limitations of existing treatments.

Read more….

http://www.phrma.org/sites/default/files/1000/phrmamedicinesindevelopmentcancer2012.pdf

 

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