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Mitochondrial Metabolism and Cardiac Function

Posted in Atherogenic Processes & Pathology, Cell Biology, Signaling & Cell Circuits, Disease Biology, Small Molecules in Development of Therapeutic Drugs, Frontiers in Cardiology and Cardiovascular Disorders, International Global Work in Pharmaceutical, Nitric Oxide in Health and Disease, Origins of Cardiovascular Disease, Personalized and Precision Medicine & Genomic Research, Pharmacotherapy of Cardiovascular Disease, Population Health Management, Nutrition and Phytochemistry, Proteomics, Technology Transfer: Biotech and Pharmaceutical, tagged Adenosine triphosphate, ATP, ATP synthase, Cardiovascular disease, Cellular respiration, Citric acid cycle, Fatty acid, Larry H. Bernstein, Mitochondrion, Nicotinamide adenine dinucleotide, Oxidative phosphorylation, TCA on April 14, 2013| 8 Comments »

Mitochondrial Metabolism and Cardiac Function

Curator: Larry H Bernstein, MD, FACP

This article is the SECOND in a four-article Series covering the topic of the Roles of the Mitochondria in Cardiovascular Diseases. They include the following;

Mitochondria and Cardiovascular Disease: A Tribute to Richard Bing, Larry H Bernstein, MD, FACP http://pharmaceuticalintelligence.com/2013/04/14/chapter-5-mitochondria-and-cardiovascular-disease/
Mitochondrial Metabolism and Cardiac Function, Larry H Bernstein, MD, FACP http://pharmaceuticalintelligence.com/2013/04/14/mitochondrial-metabolism-and-cardiac-function/
Mitochondrial Dysfunction and Cardiac Disorders, Larry H Bernstein, MD, FACP http://pharmaceuticalintelligence.com/2013/04/14/mitochondrial-dysfunction-and-cardiac-disorders/
Reversal of Cardiac mitochondrial dysfunction, Larry H Bernstein, MD, FACP http://pharmaceuticalintelligence.com/2013/04/14/reversal-of-cardiac-mitochondrial-dysfunction/

The mitochondrion serves a critical role as a platform for

energy transduction,
signaling, and
cell death pathways

relevant to common diseases of the myocardium such as heart failure. This review focuses on the molecular regulatory events involved in mitochondrial energy metabolism.

This is followed by the derangements known to occur in the development of heart failure.

Cardiac Energy Metabolism

All cellular processes are driven by ATP-dependent pathways. The heart has perpetually high energy demands related to

the maintenance of specialized cellular processes, including
- ion transport,
- sarcomeric function, and
- intracellular Ca2+ homeostasis.

Myocardial workload (energy demand) and energy substrate availability (supply) are in continual flux. Thus, ATP-generating pathways must

respond proportionately to dynamic fluctuations in physiological demands and fuel delivery.

In order to support contractile activity, the human heart requires

a daily synthesis of approximately 30kg of ATP, via
- oxidative phosphorylation at
- the inner mitochondrial membrane.

These metabolic processes are regulated, involving

allosteric control of enzyme activity,
signal transduction events, and
the activity of genes encoding
- rate-limiting enzymes and proteins.

Catabolism of exogenous substrates ,such as

fatty acids,
glucose,
pyruvate,
lactate and
ketone bodies,

generates most of the reduced compounds,

NADH (nicotinamide adenine dinucleotide, reduced) and
FADH2 (ﬂavin adenine dinucleotide, reduced),

which are necessary for mitochondrial electron transport (Fig. 1).

http://htmlimg1.scribdassets.com/8o5pfgywg0lyerj/images/2-4b87f3b3fe.jpg

Fig 1 Fatty acid beta-oxidation and the Krebs cycle produce

nicotinamide adenine dinucleotide, reduced (NADH) and
ﬂavin adenine dinucleotide, reduced(FADH2),

which are oxidized by complexes I and II, respectively, of

the electron transport chain, which comprises four complexes: I–IV.

Electrons are transferred through the chain to the ﬁnal acceptor, namely oxygen(O2).

The free energy from electron transfer

is used to pump hydrogen out of the mitochondria and
generate an electrochemical gradient across the inner mitochondrial membrane.

This gradient is the driving force for ATP synthesis via the ATP synthase. Alternatively,

H can enter the mitochondria by a mechanism not coupled to ATP synthesis, via

the uncoupling proteins(UCPs), which results in the dissipation of energy.

[ANT, adenine nucleotide translocase; CoA, coenzymeA; FAT, fatty acid transporter; GLUT, glucose transporter;

NAD, nicotinamide adenine dinucleotide; TCA, tricarboxylic acid].

Cardiac Energy Metabolic Pathways

Oxidation of free fatty acids (FFAs) and glucose in mitochondria

accounts for the vast majority of ATP generation in the healthy adult heart.

FFAs are the preferred substrate in the adult myocardium,

supplying 70-90% of total ATP.

FAs derived from circulating triglyceride-rich lipoproteins and albumin bound nonesterified FAs

are oxidized in the mitochondrial matrix by the process of beta-oxidation (FAO), whereas

pyruvate derived from glucose and lactate

is oxidized by the pyruvate-dehydrogenase (PDH) complex,
- localized within the inner mitochondrial membrane.

Acetyl-CoA, derived from both pathways,

enters the tricarboxylic acid (TCA) cycle.

Reduced flavin adenine dinucleotide (FADH2) and NADH are generated, respectively, via

substrate flux through the
- beta-oxidation and
- the TCA cycle

The reducing equivalents enter the electron transport (ET) chain,

producing an electrochemical gradient across the mitochondrial membrane
that drives ATP synthesis in the presence of molecular oxygen (oxidative phosphorylation).

The relative contributions of each of these substrates are determined

by their availability
cardiac workload and
hormonal status

In the healthy, normal heart, the ATP requirement is largely met in the actively metabolic mitochondria by

the catabolism of free fatty acids (FFAs) via beta-oxidation,
the tricarboxylic acid cycle and
oxidative phosphorylation

giving rise to a greater ATP yield per C2 unit than with glucose.

The relative contribution of glucose to the mitochondrial acetyl-coenzyme A (CoA) pool increases

during the postprandial period,
- when the heart is insulin stimulated, and
during exercise
hypoxia, or
ischemia

when glucose is favored as a more oxygen-efﬁcient substrate than

FFAs (greater ATP yield per oxygen molecule consumed).

Substrate switching in the heart can also be achieved by

acute alterations in transcriptional regulation of key metabolic enzymes
in response to alterations in substrate levels and oxygen availability, or
indeed by the intracellular circadian clock.

This continual process of ﬁne adjustment in fuel selection

allows cardiac mitochondria to function
under a range of metabolic conditions to meet the high energy demands of the heart.

Mitochondrial enzymes are encoded by both nuclear and mitochondrial genes.

All of the enzymes of

beta-oxidation and the TCA cycle, and
most of the subunits of Electron Transfer/Oxidative Phosphorylation,

are encoded by nuclear genes.

The mitochondrial genome is comprised of

1 circular double-stranded chromosome that encodes
13 ET chain subunits within complexes I, III, and IV.

Since mitochondrial number and function require both nuclear and mitochondrial-encoded genes,

coordinated mechanisms exist to regulate the 2 genomes and
determine overall cardiac oxidative capacity.

In addition, distinct pathways exist to coordinately regulate

nuclear genes encoding component mitochondrial pathways.

Early Postnatal Low-protein Nutrition, Metabolic Programming and
the Autonomic Nervous System in Adult Life.

JC de Oliveira, S Grassiolli, C Gravena, PCF de Mathias Nutr Metab. 2012;9(80)

The developmental origins of health and disease (DOHaD) hypothesis stipulates that adult metabolic disease

may be programmed during the perinatal stage.

A large amount of evidence suggests that the etiology of obesity is not only related to food abundance

but also to food restriction during early life.

Protein restriction during lactation has been used as a rat model of metabolic programming

to study the impact of perinatal malnutrition on adult metabolism.

In contrast to protein restriction during fetal life, protein restriction during lactation did not appear to cause

either obesity or the hallmarks of metabolic syndrome, such as hyperinsulinemia, when individuals reached adulthood.

Protein restriction provokes body underweight and hypoinsulinemia.
Hypoinsulinemia programs adult rats to maintain normoglycemia,

pancreatic β-cells are less sensitive to secretion stimuli:

glucose and
cholinergic agents.

These pancreatic dysfunctions are attributed to an imbalance of ANS activity

recorded in adult rats that experienced maternal protein restriction

Several studies have reported that the ANS activity is altered in under- or malnourished organisms. After weaning,

rats fed a chronically protein-deficient diet exhibited low activity of the vagus nerve,
whereas high sympathetic activity was recorded

These data were in agreement with a low insulin response to glucose.
Pancreatic islets isolated from protein-restricted rats showed

weak glucose and cholinergic insulin tropic responses
suggesting that pancreatic β-cell dysfunction may be attributed to altered ANS activity

Food abundance or restriction with regard to body weight control involves changes in

metabolic homeostasis and ANS balance activity.

Although the secretion of insulin by the pancreatic β-cells is increased in people who were overweight,

it is diminished in people who were underweight.

Changes in the ANS activity may constitute the mechanisms underlying the β-cell dysfunction:

the high PNS tonus observed in obese individuals constantly potentiates insulin secretion,
whereas the low activity reported in underweight individuals is associated with a weak cholinergic insulin tropic effect.

Under Nutrition Early in Life and Epigenetic Modifications, Association With Metabolic Diseases Risk

relevant to this issue is the role of epigenetic changes in the increased risk of developing metabolic diseases,

such as type 2 diabetes and obesity, later in life.

Epigenetic mechanisms, such as DNA methylation and/or nucleoprotein acetylation/methylation, are

crucial to the normal/physiological development of several tissues in mammals, and
they involve several mechanisms to guarantee fluctuations of enzymes and other proteins that regulate the metabolism.

The intrauterine phase of development is particularly important for the genomic processes related to genes associated with metabolic pathways.
This phase of life may be particularly important for nutritional disturbance. In humans who experienced the Dutch famine Winter in 1944–1945 and
in rats that were deprived of food in utero, epigenetic modifications were detected in

the insulin-like growth factor 2 (IGF2) and
pancreatic and duodenal home box 1 (Pdx1),

the major factors involved in pancreas development and pancreatic β-cell maturation.
The pancreas and the pancreatic β-cells develop during the embryonic phase, but the postnatal life is also crucial for

the maintenance processes that control the β-cell mass:

proliferation,
neogenesis
apoptosis.

Nutritional Restriction to the Fetus: A Risk of Obesity Onset

If an abundant diet is offered to people who have been undernourished during the perinatal life,

this opportunity induces a metabolic shift toward the storage of energy and high fat tissue accumulation

The concept of Developmental Origins of Health and Disease extends to any type of stressful situations that may

predispose babies or pups to develop metabolic disorders when they reach adulthood.

Programmed Metabolism and Insulin Secretion-coupling Process

What are the mechanisms involved in the low glucose insulin tropic response observed in low protein-programmed lean rats?
The pancreatic β-cells secrete insulin when stimulated mostly by glucose. However, several nutrients, such as

amino acids,
fatty acids,
and their metabolites,

stimulate cellular metabolism and increase ATP production.

ATP-sensitive potassium channels (KATP) are inactivated by an increased ATP/ADP ratio. This provokes

membrane depolarization and
the activation of voltage-dependent calcium channels.

These ionic changes increase the intracellular calcium concentration, which is involved in

the export of insulin to the bloodstream.

Glucose may also stimulate insulin secretion by alternative pathways involving KATP channels.

Programmed Metabolism and Insulin Tropic Effects of Neurotransmitters

Insulin release is modulated by non-nutrient secretagogues, such as neurotransmitters, which

enhance or inhibit glucose-stimulated insulin secretion.

Pancreatic β-cells contain several receptors for neurotransmitters and Neuropeptide, such as

adrenoceptors and cholinergic muscarinic receptors (mAChRs).

These receptors are stimulated by efferent signals from the central nervous system, including the ANS,

throughout their neural ends for pancreatic β-cells.

During blood glucose level oscillations, the β-cells receive inputs from

the parasympathetic and sympathetic systems to participate in glycemic regulation.

Overall, acetylcholine promotes the potentiation of glucose-induced insulin secretion,

whereas noradrenaline and adrenaline inhibit this response.

Functional studies of mAChR subtypes have revealed that M1 and particularly M3 are the receptors that are involved in

the insulin tropic effect of acetylcholine.

Interestingly, it was reported that M3mAChR gene knockout mice are

underweight,
hypophagic and
hypoinsulinemic,

as are adult rats that were protein-restricted during lactation.
The pancreatic islets from M3mAChR mice (-/-) showed a reduced secretory response to cholinergic agonists.
In studies using transgenic mice in which the pancreatic β-cell M3mAChRs are chronically stimulated,

an improvement of glycemic control has been observed

Adult male rat offspring from whose mothers were protein-restricted during lactation

exhibit a low PNS activity.

Evidence suggests that ANS changes may contribute to the impairment of glycemic homeostasis in metabolically programmed rats.

Pathways involved in cardiac energy metabolism.

FA and glucose oxidation are the main ATP-generating pathways in the adult mammalian heart.

Acetyl-CoA derived from FA and glucose oxidation is

further oxidized in the TCA cycle to generate NADH and FADH2, which
enter the ET/oxidative phosphorylation pathway and drive ATP synthesis.

Genes encoding enzymes involved at multiple steps of these metabolic pathways

uptake,
esterification,
mitochondrial transport,
and oxidation

are transcriptionally regulated by PGC-1a

with its nuclear receptor partners, including PPARs and ERRs .

Glucose uptake/oxidation and electron transport/oxidative phosphorylation pathways are also regulated by PGC-1a via

other transcription factors, such as MEF-2 and NRF-1.

[Cyt c, cytochrome c]

Fetal metabolism of carbohydrate utilization

This reviewer poses the question of whether the fetal cardiac metabolism, which is characterized by a (facultative) anaerobic glycolysis,

results in lactate production that is not redirected into the TCA cycle.

An unexamined, but related question is whether there is an associated change in the ratio of

mitochondrial to cytoplasmic malate dehydrogenase isoenzyme activity (m-MDH:c-MDH).

The fetal heart operates without oxygenation from a functioning lung, bathed in amniotic fluid.

An enzymatic feature might be expressed in a facultative anaerobic cytplasmic glycolytic pathway characterized by

a decrease in the h-type lactate dehydrogenase (LD) isoenzyme(s) (LD1, LD2) with a predominance of
the m-type LD isoenzymes (LD3, LD4, LD5).

The observation here is that the heart muscle is a syncytium, and it functions at a highly regulated rate,

not with the spurts of activity seen in skeletal muscle.

In another article in this series, there are morphological changes that occur in the heart mitochondria, and

there are three locations, as if the organelle itself were an organ.

The normal functioning myocardium can utilize lactic acid accumulated in the bloodstream during extreme exercise as fuel.

This is a virtue of mitochondrial function. There is a significant functional difference between the roles of the h- and m-type LD isoenzymes.

The h-type is a regulatory enzyme that forms a complex as NADH is converted to NAD+ between the

LD (H4, H3M; LD1, LD2),
oxidized pyridine nucleotide coenzyme, and
pyruvate

The complex forms in 200 msec as observed in the Aminco-Morrow stop-flow analyzer. This is not the case for the m-type isoenzyme.

I presume that it is not a factor in embryonic heart. It would become a factor after birth with the expansion of the lungs.

This would also bring to the discussion the effect of severe restrictive lung disease on cardiac metabolism.

Related References:

LH Bernstein, patents: Malate dehydrogenase method, The lactate dehydrogenase method

LH Bernstein, J Everse. Determination of the isoenzyme levels of lactate dehydrogenase. Methods Enzymol 1975; 41 47-52 ICID: 825516

LH Bernstein, J Everse, N Shioura, PJ Russell. Detection of cardiac damage using a steady state assay for lactate dehydrogenase isoenzymes in serum. J Mol Cell Cardiol 1974; 6(4):297-315 ICID: 825597

LH Bernstein, MB Grisham, KD Cole, J Everse . Substrate inhibition of the mitochondrial and cytoplasmic malate dehydrogenases. J Biol Chem 1978; 253(24):8697-8701. ICID: 825513

R Belding, L Bernstein, G Reynoso. An evaluation of the immunochemical LD1 method in routine clinical practice. Clin Chem 1981; 27(10):1027-1028. ICID: 844981

J Adan, L H Bernstein, J Babb. Lactate dehydrogenase isoenzyme-1/total ratio: accurate for determining the existence of myocardial infarction. Clin Chem 1986; 32(4):624-628. ICID: 825540

MB Grisham, LH Bernstein, J Everse. The cytoplasmic malate dehydrogenase in neoplastic tissues; presence of a novel isoenzyme? Br J Cancer 1983; 47(5):727-731. ICID: 825551

LH Bernstein, P Scinto. Two methods compared for measuring LD-1/total LD activity in serum. Clin Chem 1986; 32(5):792-796. ICID: 825581

PGC-1a: an inducible integrator of transcriptional circuits

The PPAR³ coactivator-1 (PGC-1) family of transcriptional coactivators is involved in regulating mitochondrial metabolism and biogenesis.

PGC-1a was the first member discovered through its functional interaction with the nuclear receptor PPAR³ in brown adipose tissue (BAT).

There are two PGC-1a related coactivators,

PGC-1² (also called PERC) and
PGC-1–related coactivator (PRC).

PRC coactivates transcription in mitochondrial biogenesis, with PGC-1a and PGC-1² . Both are expressed in tissues with high oxidative capacity, such as

heart
slow-twitch skeletal muscle, and
BAT

They serve critical roles in the regulation of mitochondrial functional capacity. PGC-1a also regulates

hepatic gluconeogenesis and
skeletal muscle glucose uptake.

PGC-1² appears to be important in regulating energy metabolism in the heart, but

PGC-1a is distinct from other PGC-1 family members, indeed from most coactivators, in its broad responsiveness to

developmental alterations in energy metabolism and
physiological and pathological cues at the level of expression and transactivation.

In the heart, PGC-1a expression increases at birth coincident with an increase in cardiac oxidative capacity and

a perinatal shift from reliance on glucose metabolism to the oxidation of fats for energy.

PGC-1a is induced by physiological stimuli that increase ATP demand and

stimulate mitochondrial oxidation, including

cold exposure,
fasting, and
exercise.

Activation of this regulatory cascade increases cardiac mitochondrial oxidative capacity in the heart. In cardiac myocytes in culture, it

increases mitochondrial number,
upregulates expression of mitochondrial enzymes, and
increases rates of FA oxidation and coupled respiration.

Thus, PGC-1a is an inducible coactivator that coordinately regulates

cardiac fuel selection and
mitochondrial ATP-producing capacity.

PGC-1a activates expression of nuclear respiratory factor-1 (NRF-1) and NRF-2 and

directly coactivates NRF-1 on its target gene promoters.

NRF-1 and NRF-2 regulate expression of mitochondrial transcription factor A (Tfam),

a nuclear-encoded transcription factor that binds regulatory sites on mitochondrial DNA and is essential for

replication,
maintenance, and
transcription of the mitochondrial genome.

Furthermore, NRF-1 and NRF-2 regulate the expression of nuclear genes encoding

respiratory chain subunits and other proteins required for mitochondrial function.

PGC-1a also

coactivates the PPAR and ERR nuclear receptors, critical regulators of myocardial FFA utilization.
regulates genes involved in the cellular uptake and mitochondrial oxidation of FFAs.
is an integrator of the transcriptional network regulating mitochondrial biogenesis and function.

Numerous signaling pathways, by increasing either PGC-1a expression or activity, such as –

Ca2+-dependent,
NO,
MAPK, and
beta-adrenergic pathways (beta3/cAMP),
- activate the PGC-1a directly

Additionally, the p38_MAPK pathway

selectively activates PPARa, which may bring about synergistic activation in the presence of PGC-1a,
whereas ERK-MAPK has the opposite effect.

These signaling pathways transduce physiological stimuli to the PGC-1a pathway:

stress
fasting
exercise

PGC-1a, in turn, coactivates transcriptional partners,which regulate mitochondrial biogenesis and FA-oxidation pathways:

NRF-1 and -2,
ERRa, and
PPARa,

Insights into the physiological responsiveness of the PGC-1a pathway come from

identification of signal transduction pathways that modulate the activity of PGC-1a and its downstream partners.

PGC-1a is upregulated in response to beta-adrenergic signaling, consistent with the involvement of this pathway in thermogenesis.

The stress-activated p38_MAPK activates PGC-1a by increasing PGC-1a protein stability and promoting dissociation of a repressor.

p38 increases mitochondrial FAO through selective activation of the PGC-1a partner, PPARa. Conversely, the ERK-MAPK pathway

inactivates the PPARa/RXRa complex via direct phosphorylation.

Therefore, distinct limbs of the MAPK pathway exert

opposing regulatory influences on the PGC-1a cascade.

Recently, NO has emerged as a novel signaling molecule proposed to integrate pathways involved in

regulating mitochondrial biogenesis by inducing mitochondrial proliferation.

A Paradox

Mitochondria are like little cells within our cells. They are the energy producing organelles of the body. The more energy a certain tissue requires

such as the brain and the heart
- the more mitochondria those cells contain.

Conventional transmission electron microscopy of mammalian cardiac tissue reveals mitochondria to be

elliptical individual organelles situated either in clusters beneath the sarcolemma (subsarcolemmal mitochondria, SSM) or
in parallel, longitudinal rows ensconced within the contractile apparatus (interfibrillar mitochondria, IFM).

The two mitochondrial populations differ in their cristae morphology, with

a lamelliform orientation in SSM, whereas
the cristae orientation in IFM is tubular.

The morphology of mitochondria is responsive to changes in cardiomyocytes.

Mitochondrial oxidative phosphorylation relies

not only on the activities of individual complexes, but also on
the coordinated action of supramolecular assemblies (respirasomes) of the electron transport chain (ETC) complexes

in both normal and failing heart.

Mitochondria have their own set of DNA and

the more energy they generate,
the more DNA-damaging free radicals they produce.

Mitochondrial DNA damage is incurred by generation of energy in ATP production, so that

the process that sustains life also is the source of toxic damage that causes the dysfunction and mitogeny in the cell.

In human mtDNA mutant cybrids with impaired mitochondrial respiration, the recovery of mitochondrial function

correlates with the formation of respirasomes suggesting that
respirasomes represent regulatory units of mitochondrial oxidative phosphorylation
- by facilitating the electron transfer between the catalytic sites of the ETC.

We recently reported a decrease in mitochondrial respirasomes in CHF that fits in the category of a new mitochondrial cytopathy.

ATP utilized by the heart is synthesized mainly by means of oxidative phosphorylation in the inner mitochondrial membrane,

a process that involves the coupling of electron transfer and oxygen consumption with phosphorylation of ADP to ATP.

The catabolism of exogenous substrates (FAs, glucose, pyruvate, lactate, and ketone bodies) provides the reduced intermediates,

NADH (nicotinamide adenine dinucleotide, reduced) and
FADH2 (flavin adenine dinucleotide, reduced),

as donors for mitochondrial electron transport.

The contribution of glucose to the acetyl CoA pool in the heart is

increased by insulin during the postprandial period and during exercise.

All cells and tissues require

adenine,
pyridine, and
flavin nucleotides for energy

by way of Krebs cycle metabolism of fatty acids and carbohydrate substrates.

If DNA holds the blueprint for the proper function of a cell, then any change in the blueprint will change how the cell functions.

If the mitochondria do not function properly, then they cannot fulfill their role in producing energy:

the cell will lose its ability to function adequately.

Glycolysis (sbbiochemania.wordpress.com)
Scien.net Publishes New Kinase and Oxidase Bibliography (prweb.com)
fatty acid breakdown (slideshare.net)
CHAPTER 5. Mitochondria and Cardiovascular Disease (pharmaceuticalintelligence.com)
Reversal of cardiac mitochondrial dysfunction (pharmaceuticalintelligence.com)

References

http://pharmaceuticalintelligence.com/2013/03/31/high-density-lipoprotein-hdl-an-independent-predictor-of-endothelial-function-artherosclerosis-a-modulator-an-agonist-a-biomarker-for-cardiovascular-risk/
Peroxisome proliferator-activated receptor (PPAR-gamma) Receptors Activation: PPARγ transrepression for Angiogenesis in Cardiovascular Disease and PPARγ transactivation for Treatment of Diabetes, Aviva Lev-Ari, PhD, RN 11/13/2012
http://pharmaceuticalintelligence.com/2012/11/13/peroxisome-proliferator-activated-receptor-ppar-gamma-receptors-activation-pparγ-transrepression-for-angiogenesis-in-cardiovascular-disease-and-pparγ-transactivation-for-treatment-of-dia/
Sulfur-Deficiciency and Hyperhomocysteinemia, L H Bernstein, MD, FACP
http://pharmaceuticalintelligence.com/2013/04/04/sulfur-deficiency-and-hyperhomocusteinemia/

Sulfur-Deficiciency and Hyperhomocysteinemia (pharmaceuticalintelligence.com)
Mitochondrial metabolism and cardiac function (pharmaceuticalintelligence.com)
Macrophage Migration Inhibitory Factor Inhibition Is Deleterious for High-Fat Diet-Induced Cardiac Dysfunction (plosone.org)
L-carnitine significantly improves patient outcomes following heart attack (eurekalert.org)
Mitochondrial Disorders Overview (geneticamedicala.wordpress.com)
An Appraisal of Human Mitochondrial DNA Instability: New Insights into the Role of Non-Canonical DNA Structures and Sequence Motifs (plosone.org)
Cardiotoxicity and Cardiomyopathy Related to Drugs Adverse Effects (pharmaceuticalintelligence.com)
Lp(a) Gene Variant Association (pharmaceuticalintelligence.com)
Predicting Drug Toxicity for Acute Cardiac Events (pharmaceuticalintelligence.com)
Amyloidosis with Cardiomyopathy (pharmaceuticalintelligence.com)

Mitochondria structure: 1 : inner membrane 2 : outer membrane 3 : cristae 4 : matrix (Photo credit: Wikipedia)

English: mechanism of fatty acids and L-carnitine going through mitochondrial membrane (Photo credit: Wikipedia)

English: Acyl-CoA from the cytosol to the mitochondrial matrix. Français : Transport de l’Acyl-CoA du Cytosol jusqu’à la matrice mitochondriale. (Photo credit: Wikipedia)

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What can we expect of tumor therapeutic response?

Posted in Biological Networks, Gene Regulation and Evolution, Biomarkers & Medical Diagnostics, CANCER BIOLOGY & Innovations in Cancer Therapy, Cell Biology, Signaling & Cell Circuits, Chemical Biology and its relations to Metabolic Disease, Disease Biology, Small Molecules in Development of Therapeutic Drugs, Genome Biology, Genomic Testing: Methodology for Diagnosis, International Global Work in Pharmaceutical, Metabolomics, Molecular Genetics & Pharmaceutical, Nitric Oxide in Health and Disease, Personalized and Precision Medicine & Genomic Research, Technology Transfer: Biotech and Pharmaceutical, tagged Anaerobic Glycolysis, ATP, Citric acid cycle, health, Mitochondrial DNA, Mitochondrion, nitric oxide, NO, Sunnybrook Health Sciences Centre, TCA on December 5, 2012| 22 Comments »

English: ATP producing pathways of glucose metabolism in aerobic respiration (Photo credit: Wikipedia)

Author: Larry H. Bernstein, MD, FCAP,

Writer, Author, Responder Clinical Pathologist, Biochemist, and Transfusion Physician _____________________________________________________________________________________________________________________________________________

Heterogeneity The heterogeneity is a problem that will take at least another decade to unravel because of the number of signaling pathways and the crosstalk that is specifically at issue. I must refer back to the work of Frank Dixon, Herschel Sidransky, and others, who did much to develop a concept of neoplasia occurring in several stages – minimal deviation and fast growing. These have differences in growth rates, anaplasia, and biochemical. This resembles the multiple “hit” theory that is described in “systemic inflammatory” disease leading to a final stage, as in sepsis and septic shock.

Tumor heterogeneity is problematic because of differences among the metabolic variety among types of gastrointestinal (GI) cancers, confounding treatment response and prognosis. A group of investigators from Sunnybrook Health Sciences Centre, University of Toronto, Ontario, Canada who evaluated the feasibility and safety of magnetic resonance (MR) imaging–controlled transurethral ultrasound therapy for prostate cancer in humans. Their study’s objective was to prove that using real-time MRI guidance of HIFU treatment is possible and it guarantees that the location of ablated tissue indeed corresponds to the locations planned for treatment. The real-time MRI guidance is an improvement in imaging technology.

The ability to allow resection with removal of the tumor, and adjacent tissue at risk is unproved, and is related to the length of remission.

See comment written for :

Knowing the tumor’s size and location, could we target treatment to THE ROI by applying…..

http://pharmaceuticalintelligence.com/2012/10/16/knowing-the-tumors-size-and-location-could-we-target-treatment-to-the-roi-by-applying-imaging-guided-intervention/

The Response vs. Recurrence Free Interval Conundrum

There is a difference between expected response to esophageal or gastric neoplasms both biologically and in expected response, even given variability within a class. The expected time to recurrence is usually longer in the latter case, but the confounders are –

age at time of discovery,
biological time of detection,
presence of lymph node and/or
distant metastasis, microscopic vascular invasion.

There is a long latent period in abdominal cancers before discovery, unless a lesion is found incidentally in surgery for another reason. The undeniable reality is that it is not difficult to identify the main lesion, but it is difficult to identify adjacent epithelium that is at risk (transitional or pretransitional). Pathologists have a very good idea about precancerous cervical neoplasia.

The heterogeneity rests within each tumor and between the primary and metastatic sites, which is expected to be improved by targeted therapy directed by tumor-specific testing. Despite rapid advances in our understanding of targeted therapy for GI cancers, the impact on cancer survival has been marginal. Brücher BLDM, Bilchik A, Nissan A, Avital I & Stojadinovic A. Can tumor response to therapy be predicted, thereby improving the selection of patients for cancer treatment? Future Oncology 2012; 8(8): 903-906 , DOI 10.2217/fon.12.78 (doi:10.2217/fon.12.78) The heterogeneity is a problem that will take at least another decade to unravel because of the number of signaling pathways and the crosstalk that is specifically at issue.

Anaerobic Glycolysis and Respiratory Impairment In 1920, Otto Warburg received the Nobel Prize for his work on respiration. He postulated that cancer cells become anaerobic compared with their normal counterpart that uses aerobic respiration to meet most energy needs. He attributed this to “mitochondrial dysfunction. In fact, we now think that in response to oxidative stress, the mitochondrion relies on the Lynen Cycle to make more cells and the major source of energy becomes glycolytic, which is at the expense of the lean body mass (muscle), which produces gluconeogenic precursors from muscle proteolysis (cancer cachexia).

There is a loss of about 26 ATP ~Ps in the transition. The mitochondrial gene expression system includes the mitochondrial genome, mitochondrial ribosomes, and the transcription and translation machinery needed to regulate and conduct gene expression as well as mtDNA replication and repair. Machinery involved in energetics includes the enzymes of the Kreb’s citric acid or TCA (tricarboxylic acid) cycle, some of the enzymes involved in fatty acid catabolism (β-oxidation), and the proteins needed to help regulate these systems. The inner membrane is central to mitochondrial physiology and, as such, contains multiple protein systems of interest. These include the protein complexes involved in the electron transport component of oxidative phosphorylation and proteins involved in substrate and ion transport. ________________________________________________________________________________________________________________________________________________________________________________ Mitochondrial Roles in Cellular Homeostasis Mitochondrial roles in, and effects on, cellular homeostasis extend far beyond the production of ATP, but the transformation of energy is central to most mitochondrial functions. Reducing equivalents are also used for anabolic reactions. The energy produced by mitochondria is most commonly thought of to come from the pyruvate that results from glycolysis, but it is important to keep in mind that the chemical energy contained in both fats and amino acids can also be converted into NADH and FADH2 through mitochondrial pathways.

The major mechanism for harvesting energy from fats is β-oxidation; the major mechanism for harvesting energy from amino acids and pyruvate is the TCA cycle. Once the chemical energy has been transformed into NADH and FADH2 (also discovered by Warburg and the basis for a second Nobel nomination in 1934), these compounds are fed into the mitochondrial respiratory chain. The hydroxyl free radical is extremely reactive. It will react with most, if not all, compounds found in the living cell (including DNA, proteins, lipids and a host of small molecules).

The hydroxyl free radical is so aggressive that it will react within 5 (or so) molecular diameters from its site of production. The damage caused by it, therefore, is very site specific. The reactions of the hydroxyl free radical can be classified as hydrogen abstraction, electron transfer, and addition. The formation of the hydroxyl free radical can be disastrous for living organisms. Unlike superoxide and hydrogen peroxide, which are mainly controlled enzymatically, the hydroxyl free radical is far too reactive to be restricted in such a way – it will even attack antioxidant enzymes. Instead, biological defenses have evolved that reduce the chance that the hydroxyl free radical will be produced and, as nothing is perfect, to repair damage. ________________________________________________________________________________________________________________________________________________________________________________ Oxidative Stress and Mitochondrial Impairment Currently, some endogenous markers are being proposed as useful measures of total “oxidative stress” e.g., 8-hydroxy-2’deoxyguanosine in urine. The ideal scavenger must be non-toxic, have limited or no biological activity, readily reach the site of hydroxyl free radical production (i.e., pass through barriers such as the blood-brain barrier), react rapidly with the free radical, be specific for this radical, and neither the scavenger nor its product(s) should undergo further metabolism. Nitric oxide has a single unpaired electron in its π*2p antibonding orbital and is therefore paramagnetic. This unpaired electron also weakens the overall bonding seen in diatomic nitrogen molecules so that the nitrogen and oxygen atoms are joined by only 2.5 bonds. The structure of nitric oxide is a resonance hybrid of two forms. In living organisms nitric oxide is produced enzymatically. Microbes can generate nitric oxide by the reduction of nitrite or oxidation of ammonia.

In mammals nitric oxide is produced by stepwise oxidation of L-arginine catalyzed by nitric oxide synthase (NOS). Nitric oxide is formed from the guanidino nitrogen of the L-arginine in a reaction that consumes five electrons and requires flavin adenine dinucleotide (FAD), flavin mononucleotide (FMN) tetrahydrobiopterin (BH4), and iron protoporphyrin IX as cofactors. The primary product of NOS activity may be the nitroxyl anion that is then converted to nitric oxide by electron acceptors. The thiol-disulfide redox couple is very important to oxidative metabolism. GSH is a reducing cofactor for glutathione peroxidase, an antioxidant enzyme responsible for the destruction of hydrogen peroxide.

Thiols and disulfides can readily undergo exchange reactions, forming mixed disulfides. Thiol-disulfide exchange is biologically very important. For example, GSH can react with protein cystine groups and influence the correct folding of proteins, and it GSH may play a direct role in cellular signaling through thiol-disulfide exchange reactions with membrane bound receptor proteins (e.g., the insulin receptor complex), transcription factors (e.g., nuclear factor κB), and regulatory proteins in cells. Conditions that alter the redox status of the cell can have important consequences on cellular function. So the complexity of life is not yet unravelled.

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Warburgh Effect

Cells seem to be well-adjusted to glycolysis. While Otto Warburg first proposed that cancer cells show increased levels of glucose consumption and lactate fermentation even in the presence of ample oxygen (known as “Warburg Effect”), which requires oxidative phosphorylation to switch to glycolysis promoting the proliferation of cancer cells., many studies have demonstrated glycolysis as the main metabolic pathway in cancer cells. It is now accepted that glycolysis provides cancer cells with the most abundant extracellular nutrient, glucose, to make ample ATP metabolic intermediates, such as ribose sugars, glycerol and citrate, nonessential amino acids, and the oxidative pentose phosphate pathway, which serve as building blocks for cancer cells.

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Dampened Mitochondrial Respiration
Since, cancer cells have increased rates of aerobic glycolysis, investigators argue over the function of mitochondria in cancer cells. Mitochondrion, a one of the smaller organelles, produces most of the energy in the form of ATP to supply the body. In Warburg’s theory, the function of cellular mitochondrial respiration is dampened and mitochondria are not fully functional. There are many studies backing this theory. A recent review on hypoxia nicely summarizes some current studies and speculates that the “Warburg Effect” provides a benefit to the tumor not by increasing glycolysis but by decreasing mitochondrial activity.

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Glycolysis
Glycolysis is enhanced and beneficial to cancer cells. The mammalian target of rapamycin (mTOR) has been well discussed in its role to promote glycolysis; recent literature has revealed some new mechanisms of how glycolysis is promoted during skin cancer development.

On the other hand, Akt is not only involved in the regulation of mitochondrial metabolism in skin cancer but also of glycolysis. Activation of Akt has been found to phosphorylate FoxO3a, a downstream transcription factor of Akt, which promotes glycolysis by inhibiting apoptosis in melanoma. In addition, activated Akt is also associated with stabilized c-Myc and activation of mTOR, which both increase glycolysis for cancer cells.
Nevertheless, ras mutational activation prevails in skin cancer. Oncogenic ras induces glycolysis. In human squamous cell carcinoma, the c-Jun NH(2)-terminal Kinase (JNK) is activated as a mediator of ras signaling, and is essential for ras-induced glycolysis, since pharmacological inhibitors if JNK suppress glycolysis. CD147/basigin, a member of the immunoglobulin superfamily, is high expressed in melanoma and other cancers.
Glyoxalase I (GLO1) is a ubiquitous cellular defense enzyme involved in the detoxification of methylglyoxal, a cytotoxic byproduct of glycolysis. In human melanoma tissue, GLO1 is upregulated at both the mRNA and protein levels.
Knockdown of GLO1 sensitizes A375 and G361 human metastatic melanoma cells to apoptosis.
The transcription factor HIF-1 upregulates a number of genes in low oxygen conditions including glycolytic enzymes, which promotes ATP synthesis in an oxygen independent manner. Studies have demonstrated that hypoxia induces HIF-1 overexpression and its transcriptional activity increases in parallel with the progression of many tumor types. A recent study demonstrated that in malignant melanoma cells, HIF-1 is upregulated, leading to elevated expression of Pyruvate Dehydrogenase Kinase 1 (PDK1), and downregulated mitochondrial oxygen consumption.
The M2 isoform of Pyruvate Kinase (PKM2), which is required for catalyzing the final step of aerobic glycolysis, is highly expressed in cancer cells; whereas the M1 isoform (PKM1) is expressed in normal cells. Studies using the skin cell promotion model (JB6 cells) demonstrated that PKM2 is activated whereas PKM1 is inactivated upon tumor promoter treatment. Acute increases in ROS inhibited PKM2 through oxidation of Cys358 in human lung cancer cells. The levels of ROS and stage of tumor development may be pivotal for the role of PKM2.

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Dampening Mitochondrial Both Cause and Effect

Warburg effect is both, a cause and effect of cancer…Review article mentioned in link below explains how different factors can contribute to metabolic reprogramming and Warburg effect….The Supply-based model and Traditional model clearly explains how the cancer cells will progress during different availability of growth factors and nutrients…And recent studies including my project (under process of getting published) will also suggest that growth factors can drive cancer cells to undergo Warburg effect regardless of the presence of oxygen…

Otto Warburg proposed that “EVEN IN THE PRESENCE OF OXYGEN, cancer cells can reprogram their glucose metabolism, and thus their energy production, by limiting their energy metabolism largely to glycolysis” . http://www.ncbi.nlm.nih.gov/pubmed

Metabolic reprogramming: a cancer hallmark even warburg did not anticipate (Ward & Thompson) Posted by Nirav Patel

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The autophagic tumor stroma model of cancer metabolism.
Cancer cells induce oxidative stress in adjacent cancer-associated fibroblasts (CAFs). This activates reactive oxygen species (ROS) production and autophagy. ROS production in CAFs, via the bystander eff ect, serves to induce random mutagenesis in epithelial cancer cells, leading to double-strand DNA breaks and aneuploidy. Cancer cells mount an anti-oxidant defense and upregulate molecules that protect them against ROS and autophagy, preventing them from undergoing apoptosis. So, stromal fibroblasts conveniently feed and mutagenize cancer cells, while protecting them against death. See the text for more details. A+, autophagy positive; A-, autophagy negative; AR, autophagy resistant.

1. Recycled Nutrients
2. Random Mutagenesis
3. Protection Against Apoptosis

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The reverse Warburg effect.
Via oxidative stress, cancer cells activate two major transcription factors in adjacent stromal fibroblasts (hypoxia-inducible factor (HIF)1α and NFκB).
This leads to the onset of both autophagy and mitophagy, as well as aerobic glycolysis, which then produces recycled nutrients (such as lactate, ketones, and glutamine).
These high-energy chemical building blocks can then be transferred and used as fuel in the tricarboxylic acid cycle (TCA) in adjacent cancer cells.
The outcome is high ATP production in cancer cells, and protection against cell death. ROS, reactive oxygen species.

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The choline dependent methylation of PP2A is the brake, the “antidote”, which limits “the poison” resulting from an excess of insulin signaling. Moreover, it seems that choline deficiency is involved in the L to M2 transition of PK isoenzymes. The negative regulation of Ras/MAP kinase signals mediated by PP2A phosphatase seems to be complex.

The serine-threonine phosphatase does more than simply counteracting kinases; it binds to the intermediate Shc protein on the signaling cascade, which is inhibited. The targeting of PP2A towards proteins of the signaling pathway depends of the assembly of the different holoenzymes.

The relative decrease of methylated PP2A in the cytosol, not only cancels the brake over the signaling kinases, but also favors the inactivation of PK and PDH, which remain phosphorylated, contributing to the metabolic anomaly of tumor cells. In order to prevent tumors, one should then favor the methylation route rather than the phosphorylation route for choline metabolism.

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Martin Canazales observes….

(http://www.cellsignal.com/reference/pathway/warburg_effect.html), is responsible of overactivation of the PI3K…

the produced peroxide via free radicals over activate the cyclooxigenase and consequently the PI3K pathway, thereby activating the most important protein-kinase. This brakes the Warburg effect, and stops the PI3K activation.

(http://www.cellsignal.com/reference/pathway/Akt_PKB.html)

Then all the cancer protein related with the generation of tumor (pAKT,pP70S6K, Cyclin D1, HIF1, VEGF, EGFrc, GSK, Myc, etc, etc, etc) get down regulated. That is what happens when one knocks down the new protein-kinase in pancreatic cancer cell lines. These pancreatic cancer cell lines divide very-very-very slowly.

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I now transition from what is understood about the metabolic signatures of cancer that tend to behave more alike than the cell of origin, but not initially. This is perhaps a key to therapeutics. >>>

Time of intervention>>> and right intervention.

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Can tumor response to therapy be predicted, thereby improving the selection of patients for cancer treatment? The goal is not just complete response. Histopathological response seems to be related post-treatment histopathological assessment but it is not free from the challenge of accurately determining treatment response, as this method cannot delineate whether or not there are residual cancer cells. Functional imaging to assess metabolic response by 18-fluorodeoxyglucose PET also has its limits, as the results are impacted significantly by several variables:

tumor type
sizing
doubling time
anaplasia?
extent of tumor necrosis
presence of tumor at the margin of biopsy
lymph node and/or distant metastasis
vascular involvement
type of antitumor therapy and the time when response was determined.

The new modality should be based on individualized histopathology as well as tumor molecular, genetic and functional characteristics, and individual patients’ characteristics, a greater challenge in an era of ‘minimally invasive treatment’. This has been pointed out by Brücher et al. if the International Consortium on Cancer with respect to the shortcoming of MIS as follows: Minimally Invasive Surgery (MIS) vs. conventional surgery dissection applied to cancer tissue with the known pathophysiology of recurrence and remission cycles has its short term advantages.

in many cases MIS is not the right surgical decision
predicting the uncertain future behavior of the tumor with respect to its response to therapeutics bears uncertain outcomes.

An increase in the desirable outcomes of MIS as a modality of treatment, will be assisted in the future, when anticipated progress is made in the field of

Cancer Research,
Translational Medicine and
Personalized Medicine,

when each of the cancer types, above, will already have a Genetic Marker allowing the Clinical Team to use the marker(s) for:

prediction of Patient’s reaction to Drug induction
design of Clinical Trials to validate drug efficacy on small subset of patients predicted to react favorable to drug regimen, increasing validity and reliability
Genetical identification of patients at no need to have a drug administered if non sensitivity to the drug has been predicted by the genetic marker.

See listing of cancers provided by Dr. Aviva Lev-Ari.

Lev-Ari A. Personalized Medicine: Cancer Cell Biology and Minimally Invasive Surgery (MIS). ________________________________________________________________________________________________________________________________________________________________________________ See comment:

Judging the ‘Tumor response’-there is more food for thought

That is an optimistic order to effectively carry out in the face of the statistical/mathematical challenge imposed for any real success.

Brücher BLDM, Bilchik A, Nissan A, Avital I & Stojadinovic A. Can tumor response to therapy be predicted, thereby improving the selection of patients for cancer treatment? Future Oncology 2012; 8(8): 903-906 , DOI 10.2217/fon.12.78 (doi:10.2217/fon.12.78) _________________________________________________________________________________________________________________________________________________________________________________ A Model Based on Kullback Entropy and Identifying and Classifying Anomalies This listing suggests that for every cancer the following data has to be collected (except doubling time). If there are 8 variables, the classification based on these alone would calculate to be very sizable based on Eugene Rypka’s feature extraction and classification. But looking forward,

time to remission and
disease free survival are additionally important.

Treatment for cure is not the endpoint, but the best that can be done is to extend the time of survival to a realistic long term goal and retain a quality of life. Brücher BLDM, Piso P, Verwaal V et al. Peritoneal carcinomatosis: overview and basics. Cancer Invest.30(3),209–224 (2012). Brücher BLDM, Swisher S, Königsrainer A et al. Response to preoperative therapy in upper gastrointestinal cancers. Ann. Surg. Oncol.16(4),878–886 (2009). Miller AB, Hoogstraten B, Staquet M, Winkler A. Reporting results of cancer treatment. Cancer47(1),207–214 (1981). Therasse P, Arbuck SG, Eisenhauer EA et al. New guidelines to evaluate the response to treatment in solid tumors. European Organization for Research and Treatment of Cancer, National Cancer Institute of the United States, National Cancer Institute of Canada. J. Natl Cancer Inst.92(3),205–216 (2000). Brücher BLDM, Becker K, Lordick F et al. The clinical impact of histopathological response assessment by residual tumor cell quantification in esophageal squamous cell carcinomas. Cancer106(10),2119–2127 (2006). _________________________________________________________________________________________________________________________________________________________________________________

The critical question encountered by the pathologist is that key histological stains have been used for some time, such as Her2, and a number of others to establish tumor cell type, and differences with cell types. The number will grow as the genomic identifiers are explored and put to use. It doesn’t appear that the pathologist will be displaced any time soon. This is separate from older observations of nuclear polymorphism, anaplastic changes related to cell adhesion, etc. These do not displace the information gained from staging criteria. Clearly, there is much information that is used for individual decisions about therapeutic approach, which will undergo further refinement even before the end of this decade.

_________________________________________________________________________________________________________________________________________________________________________________ Melanoma Example A marker for increased glycolysis in melanoma is the elevated levels of Lactate Dehydrogenase (LDH) in the blood of patients with melanoma, which has proven to be an accurate predictor of prognosis and response to treatments. LDH converts pyruvate, the final product of glycolysis, to lactate when oxygen is absent. High concentrations of lactate, in turn, negatively regulate LDH. Therefore, targeting acid excretion may provide a feasible and effective therapeutic approach for melanoma. For instance, JugloSne, a main active component in walnut, has been used in traditional medicines.

Studies have shown that Juglone causes cell membrane damage and increased LDH levels in a concentration-dependent manner in cultured melanoma cells. As one of the rate-limiting enzyme of glycolysis, 6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase isozyme 3 (PFKFB3) is activated in neoplastic cells. Studies have confirmed that an inhibitor of PFKFB3, 3-(3-pyridinyl)-1-(4-pyridinyl)-2-propen-1-one (3PO), suppresses glycolysis in neoplastic cells. In melanoma cell lines, the concentrations of Fru-2, 6-BP, lactate, ATP, NAD+, and NADH are diminished by 3PO. Therefore, targeting PFKFB3 using 3PO and other PFKFB3 specific inhibitors could be effective in melanoma chemotherapy.

This is only one example of the encouraging results from targeted therapy. An unexplored idea was provided to me that is interesting and be highly conditional, by loading with high concentrations of ketones to offset the glycolytic pathway redirected bypass of mitochondrial pathways. There is an inherent problem with muscle proteolysis raising the glucose level from gluconeogenesis. The effect is uncertain with respect to TCA cycle intermediates. It seems plausible that cure is not necessarily attainable due to inability to identify portions of proximate local tumor, modification and drug resistance. The reliable extension of disease free survival and maintaining a patient acceptable quality of life is improvable. __________________________________________________________________________________________________________________________________________________________________________________

Ward PS, Thompson CB. Metabolic Reprogramming: A Cancer Hallmark Even Warburg Did Not Anticipate. Cancer Cell. 2012; 21(3):297-308.

Quiescent versus Proliferating Cells: Both Use Mitochondria, but to Different Ends
Altered Metabolism Is a Direct Response to Growth-Factor Signaling
PI3K/Akt/mTORC1 Activation: Driving Anabolic Metabolism and Tumorigenesis by Reprogramming Mitochondria

Full-size image (51 K) Bhowmick NA. Metastatic Ability: Adapting to a Tissue Site Unseen. Cancer Cell 2012; 22(5): 563-564. _____________________________________________________________________________________________________________________________________________________________________________ Therapeutic strategies that target glycolysis and biosynthetic pathways in cancer cells are currently the main focus of research in the field of cancer metabolism. In this issue of Cancer Cell, Hitosugi and colleagues show that targeting PGAM1 could be a way of “killing two birds with one stone”. Chaneton B, Gottlieb E. PGAMgnam Style: A Glycolytic Switch Controls Biosynthesis. Cancer Cell 2012; 22(5): 565-566. ______________________________________________________________________________________________________________________________________________________________________________ The Polycomb epigenetic silencing protein EZH2 is affected by gain-of-function somatic mutations in B cell lymphomas. Two recent reports describe the development of highly selective EZH2 inhibitors and reveal mutant EZH2 as playing an essential role in maintaining lymphoma proliferation. EZH2 inhibitors are thus a promising new targeted therapy for lymphoma. Melnick A. Epigenetic Therapy Leaps Ahead with Specific Targeting of EZH2. Cancer Cell 22(5): 569-570. _______________________________________________________________________________________________________________________________________________________________________________ The microenvironment of the primary as well as the metastatic tumor sites can determine the ability for a disseminated tumor to progress. In this issue of Cancer Cell, Calon and colleagues find that systemic TGF-β can facilitate colon cancer metastatic engraftment and expansion. Calon A, Espinet E, Palomo-Ponce S, Tauriello DVF, et al. Dependency of Colorectal Cancer on a TGF-β-Driven Program in Stromal Cells for Metastasis Initiation. Cancer Cell 2012;22(5): 571-584.

_______________________________________________________________________________________________________________________________________________________________________________ An analysis of what is possible, but who knows how far into the accelerating future? Tumor response criteria: are they appropriate? The International Consortium is centered at the Billroth Institute, in Munich. Interesting it is that Billroth was the father of abdominal surgery and performed the first esophagectomy and the firat gastrectomy. He also pioneered in keeping a record of treatments and outcomes in the 19th century, which Halsted studied. I need not repeat what has been stated in the post. The pathologist’s role is still important, as the editorial in Future Oncology gets at. This also requires necessary and sufficient features to extract differentiating classifiers. I don’t think we shall see pathologists the likes of many who were masters until the 1990′s. The surgical pathologist today cannot have complete command of the large knowledge base, but the tumor registry and the cancer committee has evolved to a better stage than in the 1960′s. Surgical grand rounds have been used for teaching and evaluating the practice since at least the 1960′s. What is asked is that we go beyond that.

See comment written for:

Knowing the tumor’s size and location, could we target treatment to THE ROI by applying…..

http://pharmaceuticalintelligence.com/2012/10/16/knowing-the-tumors-size-and-location-could-we-target-treatment-to-the-roi-by-applying-imaging-guided-intervention/

________________________________________________________________________________________________________________________________________________________________________________ Evidence-based medicine Evidence-based medicine is substantially flawed because of reliance on meta-analysis to arrive at conclusions from underpowered and inconsistent studies, discarding more than half of the studies examined that don’t meet the inclusion criteria.

– There can be no movement forward without the systematic collection of data into a functionally well designed repository.
– The current construct of the EMR probably has to be “remodeled” if not “remade”.
– The studies will have to use real data, not aggregates of studies with “missing information”.
– Bioinformatics is an emerging field that is only supported in the top two tiers of academic medical centers, which would include the well known cancer centers in Boston, Houston, and New York.

I don’t place much hope in “Watson” coming to the rescue, because you have to collect both a lot of information and “sufficient” information.

-”Sufficient” information has been precluded by years of cost-elimination without paying attention to the real impact of “technologies” on costs, and an inherent competition between labor and “capital” investment.
– Despite the progress in genomics, the heterogeneity of these solid tumors is a natural adaptation that occurs in carcinogenesis.
The heterogeneity traced over a time-span should have information about stage in carcinogenesis.
The pathologist can see and interpret histologic grades in the evolution that may have a better relationship to the evolutionary studies of genomics and signaling pathways than to stage of disease, but by combining the best available evidence, you move to a better classification. Without good classification, I don’t see how you can arrive at “science based” personalized medicine.

–there is still a Rubicon to cross in going from genomics to translational medicine, which extends to diet and lifestyle.