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Posts Tagged ‘osteoblastogenesis’


Targeting bone turnover by nature-derived agents for deriving effective treatment of PCa metastases

Reporter: Ritu Saxena, Ph.D.

Introduction and basis of research: Prostate Cancer (PCa) is a leading cause of cancer-related deaths in the men of United States. Metastasis development results in high mortality rate in prostate cancer patients and PCa frequently metastasizes to the bone.

Using nature-derived agents, scientists at the Wayne State University School of medicine, Detroit, Michigan targeted bone remodeling – both bone formation and bone resorption, and proposed it as an effective strategy for the treatment of PCa bone metastasis. The treatment strategy was based on the recent observations pointing towards an increase in both osteoclastic activity and osteoblastic activity in PCa bone metastases which is contrary to the earlier belief that metastases is osteoblastic. Thus, authors designed a study targeting that both osteoclasts (bone forming cells) and osteoclasts (bone resorbing cells) activity for the treatment of PCa bone metastases

Study design: Li et al utilized formulated isoflavone and 3,39-diindolylmethane (BR-DIM) for the suppression of bone remodeling in PCa bone metastases. 3,39-diindolylmethane (DIM) is a natural agent mainly found in the members of the family Cruciferae such as broccoli, and Isoflavone is mainly found in soyabean. Isoflavone genistein has been reported to have the ability to inhibit cancer cell growth both in vitro and in vivo without toxicity. BR-DIM (manufactured by BioResponse, LLC.), as stated by the authors “could downregulate the expression of AR, Akt and NF-kB, leading to the inhibition of PCa growth and the induction of apoptosis in vitro”.  Authors thus, set out to test the hypothesis that “ a mixture of isoflavone and BR-DIM could inhibit the differentiation of osteoclasts and osteoblasts mediated through regulation of cellular signaling pathways that are involved in bone remodeling and PCa bone in vivo”.

A co-culture system involving pre-osteoclastic cell line-RAW264.7 cells, pre-osteoblastic cell line hFOB1.19, and several PCa cell lines, was established to determine how the PCa cells affect differentiation of bone cells. The effect of isoflavone and BR-DIM was then tested on both osteoclast and osteoblast differentiation and PCa cells in the co-culture system.

Results: Isoflavone and BR-DIM inhibited bone remodeling through the inhibition of cell signal transduction associated with osteoclast differentiation (RANKL-mediated signaling), osteoblast differentiation (RUNX2, periostin gene), and PCa growth and signaling. Isoflavone and BR-DIM, infact, were shown to affect multiple signaling pathways that could possibly be useful in the prevention of PCa progression especially in the context of bone metastases.

The study highlights an important message that natural agents could be a source for deriving agents that could be useful in the treatment of diseases such as cancer without toxicity issues.

Sources: Research Article – Li Y, Kong D, Ahmad A, Bao B, Sarkar FH. Targeting bone remodeling by isoflavone and 3,3′-diindolylmethane in the context of prostate cancer bone metastasis. PLoS One. 2012;7(3):e33011. http://www.ncbi.nlm.nih.gov/pubmed?term=22412975

UroToday report: http://www.urotoday.com/UroToday/Prostate-Cancer/targeting-bone-remodeling-by-isoflavone-and-3-3-diindolylmethane-in-the-context-of-prostate-cancer-bone-metastasis-beyond-the-abstract-by-fazlul-h-sarkar-phd-et-al.html

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Curator and Reporter: Ritu Saxena, Ph.D.

Recently, an article published in the journal Bone described that the low magnitude vibrations might be helpful in mitigating osteopenia in spontaneous granulosa cell ovarian cancer.

Osteopenia is defined as the bone mineral density (BMD) that is lower than normal peak BMD but not low enough to be classified as the diseased condition called osteoporosis. Bone mineral density is a measurement of the level of minerals in the bones, that shows how dense and strong they are. Having osteopenia means there is a greater risk that, as time passes, you may develop BMD that is very low compared to normal, known as osteoporosis

Cancer progression is often paralleled by a decline in bone mass, raising risk of fracture. Loss in bone mass can be therapeutically treated by using bone anabolic agents that increase the process of bone formation compared to bone resorption thus leading to an overall increase in bone mass. However, use of anabolic agents for preventing cancer associated bone loss presents a lot of concern as they may exacerbate cancer tissue expansion.

Bone is a mechanosensitive organ. Osteoblastogenesis, or the process of differentiation of precursor cells to bone forming cells (osteoblasts) is encouraged by low intensity vibration (LIV) via a mechanical signal. Rubin et al explored the possibility of slow cancer-associated bone loss, but this goal must be achieved without fostering disease progression. The hypothesis was tested in the murine model.

Seventy female F1-SWRxSWXJ-9 mice, a strain prone to developing granulosa cell tumors, were divided into three groups – baseline control (BC: n=10), age-matched control (AC: n=30), and LIV (n=30), which received mechanical signals (90Hz @ 0.3g) for 15m/day, 5day/w over the course of 1year. Survival curves observed in the three groups indicated that longevity was unperturbed by LIV. Rubin et al stated that “1year, bone volume of proximal tibiae in LIV mice was 25% greater than AC while bone volume of L5 vertebrae was 16% higher in LIV over AC (p<0.02). Primary lesions and peripheral metastases were apparent in both LIV and AC; however, overall tumor incidence was approximately 30% less in LIV (p=0.27) and, when disease was evident, involved fewer organ systems (p=0.09).”

These experiments indicate that LIV helps protect bone mass in mice inherently susceptible to cancer without compromising life expectancy, perhaps through mechanical control of stem cell fate. Further, these data reflect the numerous system-level benefits of exercise in general, and mechanical signals in particular, in the preservation of bone density and the suppression of cancer progression.

Source: Journal article- http://www.thebonejournal.com/article/S8756-3282(12)00867-8/abstract, http://www.webmd.com/osteoporosis/tc/osteopenia-overview

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