THE CANCERIZATION/DE-CANCERIZATION DYNAMICS
Altering the Behavior of Cancer Cells: Fermentative-to-Respiratory (FTR) Shift. A cancer cell, like T. pantotropha, is also a metabolic two-timer, but with a difference: it survives in the presence of oxygen, but thrives in its absence. The singular challenge in the field of cancer—in my view—is this: Can we create oxygen conditions in the body that coax a cancer cell to relinquish its infatuation with the respiratory-to-fermentative (RTF) shift, and revert back to its human respiratory mode of ATP generation with a fermentative-to-respiratory (FTR) shift? In other words, can the predominantly glycolytic metabolism mode of a cancer cell be switched to the physiologic respiratory ATP energetics of a healthy cell, fundamentally altering its energetic behavior? That is a tantalizing possibility. But, what may be realistically hoped for here? I see limited value of chemotherapeutic agents in this endeavor. (Excerpted from Cancer, Oxygen, and Pantotropha, Part I, Townsend Letter, November 2004.)
II. The Cancerization/De-cancerization
Dynamics of the Dysox Model of Cancer
III. Levels of Can/De-Can Dynamics
IV. Oxygen, Three Furies of Cancer, and the
V. Oxygen, 3C Cascades, and the Can/De-Can
VI. Oxygen, 3M Ecosystems, and the Can/De-Can Dynamics
VII. Oxygen, Hypoxia-Inducible Factor, and the
VIII. Oxygen, Inflammation, and the Can/De-Can
IX. Oxygen, the Bowel, and the Can/De-Can
X. Pre-Genes, Genes, Epigenes, and the
XI. Apoptosis and the Can/De-Can Dynamics
XII. Why Doesn’t Everyone Have cancer? The DNA-Damage Response
XIII. Angiogenesis and the Can/De-Can Dynamics
XIV. Dysox-to-Detox-to-Reox: The Sun-Soil
Model for the Can/De-Can Dynamics
XV. Closing Comments
Cancer is considered a genetic disorder. My primary purpose in writing this article is to challenge that view and to assert this: Cancer is an oxygen problem, before it becomes a gene problem. The basis of that statement is simple: Oxygen conditions govern the behavior of genes — oncogenes that promote carcinogenesis as well the tumor suppressor genes that prevent it — and either set the stage for carcinogenesis or prevent the development of cancer. To expand on that theme, I begin by succinctly stating its three core messages:
1. All aspects of the microenvironment of cancer —the so-called tumor/host dynamics—are governed by oxygen conditions of cancer cells and of normal cells in their vicinity— oxyecology seems to be a suitable term for those conditions;
2. In the cancer/host dynamics, the elements of host (soil) are far more important than those of cancer cells (seed), except when an early cancer can be resected in toto; and
3 No therapeutic agent—synthetic or putatively ‘natural’—can be expected to yield good long-term clinical outcome by killing cancer cells or curbing their survival by direct drug toxicity, by modulating the functionalities of some proteins, or by altering the behavior of some genes.
The central tragedy of oncology—in my view —is that it completely ignores the crucially important issues of the microenvironmental oxygen conditions of cancer and of non-cancerous tissues in its vicinity. By cancer oxyecology I refer not only to the glycolytic metabolic conditions within cancer cells that cause and perpetuate oxidosis, acidosis, and dysoxygenosis (dysox)—the three furies of cancer—but also to the effects of that trio on the commerce in the matrix, as well as on cellular differentiation, dedifferentiation, and demise. Cancer biologists are beginning to recognize this critical issue. Regrettably, oncologists, by and large, continue to completely neglect the crucial issues of cancer oxyecology. Persons with cancer pay an enormous price when oncologists focus on cancer but de-focus on the patient.
A clear understanding of the scientific basis of the central role of oxygen in the tumor/host interaction —in my view—provides integrative clinicians the scientific basis and/or rationale for their natural detoxification and oxystatic therapies of empirically proven integrative therapies.
I support my three assertions stated above by marshaling several lines of evidence. I focus on the signaling and genetic pathways activated and perpetuated by abnormal oxygen conditions prevailing in cancer cells, on the malignant as well as the benign matrix, and on the non-cancer cells surrounding the cancer cells. Specifically, I address the dynamics of: (1) the metabolic trio of cancer cells—oxidosis, acidosis, and dysoxygenosis (dysox), which includes respiratory-to-fermentative shift; (2) dysox-inflicted metabolic shifts in non-cancer cells surrounding cancer cells; (3) oxidative coagulopathy in cancer; (4) biomatrix disturbances in cancer; (5) biology of hypoxia-inducible factors; (6) hypoxia response elements; (7) hypoxia-inactivated tumor suppressor genes, such as p53; (8) hypoxia-activated oncogenes, such as Ras oncogene; (9) hypoxia-induced activation of proinflammatory genes, such as plasminogen activator inhibitor-1 (PAI-1) and cyclooxygenase 2 (COX-2); (10) hypoxia-activated genes that link cancer with thrombohemorrhagic phenomena, such as MET gene; (11) hypoxia-suppressed apoptosis of cancer cells; (12) hypoxia-triggered angiogenesis, including overexpression of the genes coding for growth factors, such as vascular endothelial growth factor (VEGF); and (13) the effects of altered oxyecologic conditions on genetic pathways involved in oncogenesis in the bowel.
II. THE CANCERIZATION/DE-CANCERIZATION DYNAMICS OF THE DYSOX MODEL OF CANCER
In 2004, I published the Dysox Model of cancer as a unifying model that brings together many disparate and some seemingly paradoxical bichemical, morphologic, and clinical observations concerning the biology of cancer.1 In this column, I present the “cancerization-de-cancerization (can/de-can) dynamics” of that model to underscore the critical importance of cancer oxyecology. Dysox, as noted earlier, is the abbreviation of dysoxygenosis, a state of dysfunctional oxygen metabolism caused by impaired function of oxyenzymes and altered expression of oxygenes, and includes respiratory-to-fermentative shift.2-7 The can/de-can dynamics govern all aspects of cancer biology, including cellular multiplication, local growth, and formation of distant metastases. Needless to say, a clear understanding of the cancer/host interactions is crucially important for designing scientifically sound therapies that can then be validated by long-term clinical outcome studies.
By the expression cancerization of non-cancer cells, I mean a process by which cancer induces the dysox state—including respiratory-to-fermentative shift —in non-cancer cells. After variable periods of time, non-cancer cells with those shifts acquire some of the genetic expressions of cancer cells. That involves myriad metabolic, signaling, and genetic mechanisms by which cancer cells multiply and assure their survival. The concept of cancerization of non-cancer cells evolved from my pathologic studies of diverse cancers and biochemical abnormalities encountered in my patients with cancer.
By the expression de-cancerization of cancer cells, I mean the process by which non-cancer cells counter the metabolic, signaling, and growth aspects of cancer cells. Those “shifts in cancer behavior,” if maintained for extended periods of time, can be expected to induce some genetic changes in cancer cells as well. The concept of de-cancerization of cancer cells essentially evolved from my clinical observations described at length in Oxygen, Cancer, and the Crab,8 some of which I presented in Part I of this column. 9
III. LEVELS OF CAN/DE-CAN DYNAMICS
The cancerization/de-cancerization dynamics can be viewed at different levels. The following—in my view—are the essential issues:
1. Three core metabolic characteristics of cancer —oxidosis, acidosis, and dysoxygenosis—by which cancer cells induce the dysox state (including respiratory-to-fermentative shift) in non-cancer cells and recruit them to subserve cancer cells in the pursuit of expansion;
2. Hypoxia-induced activation of enzymes, redox-restorative factors, growth factors, DNA response elements, gene expression, and epigenomic responses that foster the growth and spread of malignant cells;
3. Oxygen-mediated abnormalities of the coagulation, complement, and caspase systems—the 3C pathways—that set the stage for oxidative coagulopathy and neoplastic angiogenesis;
4. Hypoxia-inflicted changes in the matrix, membrane, and mitochondria (the 3M dynamics).
5. Hypoxia-induced neoplastic angiogenesis through activation of hypoxia-inducible factor (HIF) pathways;
6. Development of metastases by genetic mechanisms activated by the oxyecologic conditions of cancer, including those of MET and other oncogenes;
7. Oxyecologic resistance of non-cancer cells surrounding malignant cells to RTF shift;
8. Creation of oxyecologic conditions by normal cells surrounding cancer cells that induce cancer cell apoptosis and/or compromise cancer cell survival; and
9. Clinical benefits of oxystatic therapies that preserve and/or restore the integrity of the bowel, blood, and liver ecosystems and powerfully support the de-cancerization arm of the can/de-can dynamics in controlling and/or eradicating cancer.
Figure 1. Three Core Characteristics of Cancer That Initiate Cancerization of Non-Cancer Cells
In Figures 1 and 2, I present simple schemata to give my sense of the order of importance of the above considerations, both for understanding cancerization/ de-cancerization dynamics and for designing therapeutic strategies to positively influence those dynamics in the treatment of cancer.
Figure 2. Trio of Major Molecular and Structural Components of the Can/De-Can Dynamics of the Oxygen Model of Cancer
IV. OXYGEN, THREE FURIES OF CANCER, AND THE CAN/DE-CAN DYNAMICS
Cancerization of non-cancer cells begins with the three core characteristics of cancer—oxidosis, acidosis, and dysoxygenosis—which, like the three furies of Greek myth, are relentless in their destructive behavior (Figure 1). The effects of all those furies are vigorously opposed by the oxygen-driven, anti-oxidant, and acid-base buffering mechanisms of non-cancer cells surrounding malignant cells. Intracellular acidosis is one of the hallmarks of metabolism in cancer cells. It is created largely by prodigious production of lactic acid, which is sometimes called the Warburg effect (to honor Otto Warburg, who originally described it and received a Nobel Prize in 1931 for his work with glycolysis). 10,11 I described some aspects of Warburg’s work in Cancer, Oxygen, and Pantotropa, Part I, the first of this series of articles, in which I also questioned his notion of irreversibility of the glycolytic mode of metabolism in cancer.79
De-cancerization of cancer cells begins with up-regulation of enzymatic, nonenzymatic, genetic, and epigenetic mechanisms in non-cancer cells to oppose and neutralize the three furies of cancer. The restoration of oxygen homeostasis, redox equilibrium, and acid-base equilibrium in the cancer microenvironment not only slows the proliferation and spread of cancer cells, it also initiates apoptotic and non-apoptotic mechanisms to induce cancer cell death. That, of course, is the scientific basis of all oxystatic therapies in the treatment of cancer, whether with direct therapies (hydrogen peroxide, ozone, singlet oxygen, oxygen by mask) or indirect (naturopathic bowel, blood, and liver detoxification) described in detail in Dysoxygenosis and Oxystatic Therapies, the third volume of The Principles and Practice of Integrative Medicine.12
A critical issue in this context which is seldom, if ever, duly considered is of the integrity of the anatomic boundaries that play crucial roles in controlling the spread of cancer. Those boundaries are mostly composed of robust connective tissue that is far less vulnerable to the vicissitudes of cancer oxyecology than are the parenchymal tissues in various body organs. This is an important consideration in the choice of the treatment plan in many instances—for example, highly motivated, well-informed individuals may elect to forgo biopsy before receiving natural therapies for prostate tumors when associated with rising levels of the prostate-specific antigen and/or when clear ultrasound or MRI evidence of cancer exists.
Figure 3. Pre-Genes, Genes, and Epigenes Affecting Cancer Oxyecology
V. OXYGEN, 3C CASCADES, AND
THE CAN/DE-CAN DYNAMICS
About four years ago, an unusual pattern of vasculitis in a 46-year-old woman prompted me to conduct a work-up for an underlying occult malignancy. A CT scan of the abdomen revealed a pancreatic mass, which proved to be adenocarcinoma on resection. At the time of this writing four years after surgery, she is in excellent health, without any demonstrable recurrent cancer or vasculitis. Such a case, of course, is not a rarity. The association between cancer and thrombohemorrhagic tendencies has been extensively documented in a broad spectrum of malignancies.13,14
The molecular-genetic basis of the association between cancer and thrombohemorrhagic events remained elusive until very recently. Below, I reproduce some text from one of my previous publications to provide a historical framework for summarizing our current knowledge about how oxygen links cancer with ‘spontaneous’ clotting:
In 1842, T.W. Jones, a British physician, asked the question: Why doesn’t the blood circulating in the vessels coagulate? This question has intrigued blood coagulation researchers ever since. In 1845, Rudolph Virchow, the German physician and father of pathology, responded to the question raised by Jones by stating that under certain circumstances circulating blood does coagulate, and he speculated what those pathologic states might be. Almost simultaneously, A. Trousseau, a French physician, observed that circulating blood does coagulate in the vessels in certain conditions and reported clinical observations to support Virchow’s speculation. Trousseau’s syndrome is the name still used when thrombophlebosis is associated with malignant diseases. In 1893, Dastre first proposed the term “fibrinolyse” for his observations on the dissolution of blood clots. However, his were not among the earliest observations on fibrinolysis. John Hunter, the eighteenth-century London surgeon, included his observation on clot dissolution in his famous treatise on blood.15
In 1997, my colleague Omar Ali and I introduced the term oxidative coagulopathy and described in detail the morphologic features of this entity.15 Since then, with high-resolution phase-contrast microscopy I have observed varying degrees of oxidative coagulopathy in all patients with disseminated cancer. In this context, I consider Trousseau’s syndrome to be merely an advanced state of oxidative coagulopathy.16
What role does oxidative coagulopathy play in the can/de-can dynamics of cancer? Thrombin is one of the initiators of angiogenesis in cancer, a process by which cancer secures its growth requirement by generating new blood vessels. While fibrin is also an angiogenesis trigger, thrombin’s role in angiogenesis is independent of that protein. Specifically, thrombin initiates and sustains cancerous neovascularization by one of the following mechanisms: (1) it stimulates endothelial cell proliferation by greatly potentiating vascular endothelial growth factor (VEGF); (2) it diminishes the ability of endothelial cells to find a strong anchor in basement membrane proteins; (3) it upregulates the expression of VEGF receptors (kinase insert domain-containing receptor [KDR] and fms-like tyrosine kinase [Flt-1]); (4) it increases the mRNA and protein levels of alpha V beta 3 integrin and serves as a ligand to that receptor; and (5) it amplifies the synthesis of matrix metalloprotease-9 and alpha V beta 3 integrin in certain types of cancer cells, including prostate cancer PC3 cells.17,18 By all those mechanisms —and almost certainly others waiting to be revealed—
thrombin serves as a pro-cancer molecule. Not surprisingly then, there is much interest in the pharmaceutical industry for the development of thrombin receptor mimetics or antagonists.
During the last decade, considerable evidence has been developed showing the central role of oxygen dynamics in linking cancer with thrombohemorrhagic events. One such line of evidence concerns the MET oncogene, which is activated in a wide array of human neoplasms as a consequence of both germline and sporadic somatic mutation.19,20 Furthermore, the role of hypoxia-induced transcription in activation of MET gene has been established in many studies.21,22 In recent weeks, that link has been firmly established by Boccaccio et al., who delineate the molecular-genetic pathways by which cancer causes thrombohemorrhagic events. 23
In a mouse model of sporadic tumorigenesis based on genetic manipulation of somatic cells, Boccaccio et al. caused slowly progressing hepatocarcinogenesis by targeting the activated human MET oncogene to adult liver cells. Carcinogenesis was preceded and accompanied by initial blood hypercoagulability and venous thromboses, and later fatal internal hemorrhages. The pathogenesis of that association was found to be driven by the transcriptional response to MET oncogene, which resulted in activation of 71 distinct genes—among them most notably were prominent upregulation of plasminogen activator inhibitor type 1 (PAI-1) and cyclooxygenase-2 (COX-2) genes.26 Further in vivo studies showed that both proteins support the thrombohemorrhagic phenotype, thus revealing a direct genetic link between oncogene activation and hemostasis.
A cancer cell is a cunning metabolic two-timer — in more than one way. In one way, it clots proteins to build a protective cocoon to keep out molecular species and cells that pose danger to it. In another way, it dissolves clotted proteins in its way to pursue its expansionist goals. To cite one example, prostate-specific antigen (PSA) is a commonly used biomarker for prostate cancer. Notwithstanding its shortcomings as a tumor marker—there are none without any shortcomings —PSA is a serine protease, in which role it degrades proteins and paves the way for cancer cells to advance. In my view this is the likely explanation of the common observation that the serum free PSA levels are lower in prostate cancer than in benign prostatic hyperplasia.24
The biologic activities of thrombin, and the other components of the coagulation cascade triggered by it, are intricately interwoven with the complement and caspase cascades, an important subject covered at length in Nature’s Preoccupation with Complementarity and Contrariety, the first volume of The Principles and Practice of Integrative Medicine. 25 It is also important to recognize that thrombic and other components of the 3C cascades play a multitude of pro-cancer and anti-cancer roles. This issue is of great interest in integrative medicine, where the focus is always on integrating various therapies to holistically address the pathophysiological changes throughout the body. That is especially necessary in the clinical application of the Oxygen Protocol for treating cancer (to be detailed in a subsequent column on the subject). I present the subject of the Dr. Jekyll and Mr. Hyde roles of thrombin and other related molecular species at length in Dysoxygenosis and Oxystatic Therapies and Integrative Oncology, the third and the ninth volumes of The Principles and Practice of Integrative Medicine.26,27
To summarize this section, to sustain their momentum for growth and spread, cancer cells need to be able to — and are capable of — generating both clotting and unclotting proteins in the fluids that bathe them. To grow, those cells first cause protein clots to stop non-cancer cells from attacking them and then produce proteases to dissolve those clots to advance themselves.
VI. OXYGEN, 3M ECOSYSTEMS, AND
THE CAN/DE-CAN DYNAMICS
In previous publications, I have described at length how the trio of oxidosis, acidosis, and dysoxygenosis inflict injury on the matrix, membrane, and mitochondria (the 3M dynamics).28,29 Especially vulnerable are the crucial signaling pathways provided by functional proteins, which are anchored in the matrix and traverse cell membranes multiple times. Such proteins create conduits for information commerce between the matrix and cell innards. Of special significance in this context are the matrix metalloproteinases, tissue inhibitors of metalloproteinases, and other redox-active enzymatic and non-enzymatic factors. 30,31
In this column, I introduce the term ‘biomatrix oxygen homeostasis’ for three reasons. First, ‘biomatrix’ is a better term than the prevailing ‘connective tissues,’ since it carries a clear connotation of biological functions. Second, it emphasizes the centrality of oxygen in biomatrix functionalities. (One seldom, if ever, sees any references to oxygen homeostasis and disruptions of that in medical literature.) Third, considerations of biomatrix oxygen dynamics bring into sharp focus the structural and functional aspects of matrix metalloproteins and metalloproteinases in the pathogenesis of all disease processes, and especially in the development of metastases.
Biomatrix possesses physical, chemical, and mechanical properties that uniquely support the cells in various body organs. It turns out that biomatrix functionalities are more critical than those in cells, in the sense that it needs to be recognized that biomatrix is functionally more resilient than cells. This is a matter of crucial importance in the context of the cancerization/de-cancerization dynamics, since biomatrix is far more resistant than cells to acidifying, oxidizing, and dysoxygenizing influences of cancer cells. As a consequence, biomatrix counters tumor cell invasion and angiogenesis for extended periods of time, as witnessed in the slow progression of in-situ phases of epithelial cancer and rapid spread of tumor once biomatrix barriers are breached.
Metalloproteins—one-third of all proteins in the body—are composed of various elements (carbon, nitrogen, oxygen, hydrogen, and sulfur) with ions of metals such as iron, calcium, copper, and zinc. Driven by oxygen dynamics in biomatrix, such proteins confer upon biomatrix nearly all of their biologic functions, except some aspects of their structure. Biomatrix metalloproteinases (MMPs) are a family of fifteen (possibly more) secreted and membrane-bound zinc endopeptidases. These are degradative enzymes that break down all components of biomatrix, including fibrallar and non-fibrallar collagens, fibronectin, laminin and basement membrane glycoproteins. In health, MMPs serve essential roles in biomatrix repair and modeling. In cancer, these proteases are ‘over-activated’ by the malignant trio of oxidosis, acidosis, and dysoxygenosis; cause excessive breakdown of structural components of biomatrix; and pave the way for invasion by malignant cells. It also appears that cancer-induced disturbances in zinc dynamics in biomatrix are involved in cancer spread and the formation of metastases. This might be one of the explanations why EDTA chelation is of clinical benefit in the treatment of cancer (personal unpublished observation).
It is clear that cancer-associated stroma vigorously and robustly interacts with the molecular dynamics of cancer cells. For instance, it is known that tumor cells harvested from metastatic lesions not only represent a subpopulation of preexisting tumor cells, but also clones of newly acquired variants, which evolve as a consequence subsequent to tumor-stromal interactions. For example, in the case of prostate cancer, permanent genetic and phenotypic alterations develop when tumor cells are co-cultured and grown with inductive stromal cells in vivo.32
Benign and malignant biomatrix receives from microvascular endothelial cells a large number of growth and survival factors.33,34 Twenty such endothelial-derived paracrine factors have been delineated34 — the best known among them are vascular endothelial growth factor (VEGF), basic fibroblast growth factor (bFGF), platelet-derived growth factor (PDGF), insulin-like growth factor-1 (IGF-1), heparin-binding epithelial growth factor and interleukin-6. From the perspective of the oxygen order of biology, one would expect that such paracrine factors of biomatrix would link oxygen-regulated proteins with angiogenesis, steroid biochemistry, hemorrhagic-thrombotic pathways, and others. That indeed is the case. I site the following seven illustrative examples of molecular linkages of special interest in the context of the can/de-can dynamics of the dysox model of cancer: (1) Normal tissue mass is closely regulated by vascular paracrine factors35; (2) Steroid hormones mediate generation of angiogenic peptides — castration decreases and testosterone increases production of VEGF mRNA expression in the prostate36; (3) Angiostatin, an angiogenesis inhibitor derived from plasminogen, is released under the influence of macrophage metalloelastase37,38; (4) Other angiogenesis inhibitors — endostatin and possibly others — are released from biomatrix proteins other proteins39; (5) androgen deprivation of LnCap human prostate carcinoma cells markedly reduces VEGF mRNA expression, and androgen withdrawal inhibited the hypoxic induction of VEGF36; (6) Antithrombin — a member of the serpin family of proteins — not only inhibits thrombin and related proteases but in its conformation also serves important antiangiogenesis and anti-tumor roles40; and (7) Molecular crosstalk is known to occur between spent coagulation factors and adhesion receptors,41 for instance conformational loss of affinity of PAI-1 for matrix vitronectin is associated with affinity for other cell surface receptors.42 (m10)
I have two objectives in the above presentation of some salient exmaples of molecular linkages in the biomatrix: (1) First is to emphasize the crucial importance of the the ‘matrix nature’ of the molecular crosstalk in the microenvironment of cancer; and (2) Second, to underscore my view that no single agent — whether angiogenesis inhibitor or modifier of some gene expression can be expected to provide us with long-term control of cancer, unless all issues of the cancer oxyecology are vigorously addressed.
VII. OXYGEN, HYPOXIA-INDUCIBLE FACTOR, AND THE CAN/DE-CAN DYNAMICS
Medical models are proposed to explain natural phenomena and to design rational therapeutic plans for improved clinical outcome. The central tenet of the dysox model of cancer holds that the derangement of oxygen homeostasis is at the root of all aspects of cancer metabolism. The replication and spread of cancer, and consequent death, must be related to oxygen and oxygen phenomena. Specifically, each and every aspect of can/de-can dynamics must truly represent all known tumor/host empirical observations and the clinical results achieved with non-pharmacologic regimens. In this section, I look at that issue through the biological prism of hypoxia-inducible factors (HIF).
Hypoxia-inducible factor-1 (HIF-1) is a heterodimer transcription protein consisting of an alpha and beta subunit.43,44 It is so designated because the binding of HIF-1 with DNA is induced in response to hypoxia. Predictably, in view of nature’s preoccupation with complementarity and contrariety, there are negative regulators of hypoxia-inducible gene expressed. Among them is the inhibitory PAS domain protein. 45
Overexpression of HIF-1 has been commonly encountered in diverse human cancers, as well in their metastases.46 HIF stabilizes wild-type p53. 47 The tumor suppressor protein VHL targets HIF for oxygen-driven degradation by proteolysis. 48 Tert-butyl hydroperoxide induces apoptosis. Such cellular demise in hypoxic cells is prevented by HIF-induced overexpression of myeloid cell factor-1.49 Activation of HIF-1 also occurs in abnormal neovascularization in bacterial infections. For instance, such activation has been shown in angiomatosis associated with bacillary infections.50
Erythropoietin (EPO), a glycoprotein hormone, is the primary regulator of erythrocyte production. Not unexpectedly, hypoxia is the primary inducer of the EPO gene. The increased production of EPO occurs primarily at the transcriptional level and involves binding of HIF-1 to a hypoxia-inducible enhancer in the 3′ flanking sequence of the EPO gene. Both the HIF-1 alpha and beta subunits can independently co-transactivate the EPO enhancer; however, binding of both subunits and a hypoxic environment is necessary for maximal transactivation. To add to the complexity, it has been shown that overexpression of the HIF-1 protein alone in normoxic or hypoxic conditions is insufficient for increased EPO production. Furthermore, co-transactivation experiments employing EPO-producing human hepatoma cell line (Hep 3B) and a non-EPO-producing monkey kidney cell line (Cos-7) revealed that activation/inactivation and interaction of tissue-specific factors other than HIF-1 are necessary for increased production of EPO in response to hypoxia.51
Hypoxia triggers expression of RORalpha— the gene that codes for retinoic acid receptor-related orphan receptor alpha—at the transcriptional level. This expression is dependent on a hypoxia-responsive element (HRE) located downstream of the promoter. The hypoxia-responsive region of the RORalpha4 promoter is composed of the HRE and GC-rich sequences and the transcriptional activation under hypoxia is conferred through the cooperation of HIF-1 with Sp1/Sp3. It is also now known that HIF-1 alone cannot activate transcription in hypoxic conditions without support from other moieties, such as Sp1/Sp3, which binds to a cluster of GC-rich sequences adjacent to the HRE.52
VIII. OXYGEN, INFLAMMATION, AND THE CAN/DE-CAN DYNAMICS
Cancer causes inflammation. The inflammatory response incited by cancer feeds cancer. This is one of the essential messages of this column. In a recent column entitled “Oxygen Governs the Inflammatory Response and Adjudicates Man-Microbe Conflicts,”53 I summarized a very large number of personal, clinical, phase-contrast, and biochemical observations that led me to formulate clinical concepts based on morpho-observations concerning oxidative coagulopathy, oxidative regression to primordial cellular ecology, and dysoxygenosis (including respiratory-to-fermentative shift). All of those considerations are directly relevant to a clear understanding of the development, growth, and spread of cancer. In this section, I offer some additional information on the pathogenesis of cancer.
Inflammation contributes to carcinogenesis by several intertwined mechanisms. For example, inflammation causes: (1) generation of mutagenic oxyradicals and nitrosoradicals; (2) production of cytokines and growth factors that stimulate and sustain cancer cell growth; and (3) induction of cyclooxygenase-2 in macrophages and epithelial cells. Histologically, malignant tumors are nearly always accompanied by epithelial and stromal infiltrates of lymphocytes, histiocytes, plasma cells, and scattered mononuclear cells. Heterogeneous expression of the GSTP1 gene—involved with glutathione antioxidant system—in such inflammatory infiltrates has been considered as evidence for oxidative damage and continuing growth of tumors.54
During my work as a hospital pathologist, my colleagues and I commonly observed histopathologic evidence for the inflammation/cancer axis of evil. It has long been recognized that chronic inflammation sets the stage for the oncogenesis of cancer. I coined the 0,1,2, cancer mnemonic to succinctly state the role of inflammation in that relationship. The overexpression of PAI-1 and COX-2 genes induced by activation of MET gene is, of course, of special relevance to hypoxia-inducible genetic factors mediated by oxygen.55-57
IX. OXYGEN, THE BOWEL, AND THE CAN/DE-CAN DYNAMICS
The bowel was considered by the ancients— and continues to be so regarded by integrative modern physicians—as the seat of health and the primary cause of chronic illness.
Recent advances in genomics and molecular signaling have clearly delineated many intertwined molecular mechanisms that regulate homeostatic self-renewal of the bowel lining.58–66 That body of knowledge has shed much light on carcinogenesis in the bowel. The major signaling and genetic pathways include Wnt, bone morphogenic protein, Notch signaling cascades, and Hedgehog signals. The adenoma-carcinoma sequence of tumor progression involves: (1) multiplicity of gene mutations; (2) mutational activation of oncogenes; (3) inactivation of tumor-suppressor genes; (4) accumulations of genetic alterations; and (5) mutations in mismatch repair genes, such as MSH2 and MLH1.67,68
Hereditary cancer syndromes fall into two categories: (1) hereditary nonpolyposis colorectal carcinoma; and (2) familial adenomatous polyposis (FAP). The hallmark of hereditary nonpolyposis is instability of microsatellites, which are repeats of short DNA sequences.69,70 Indeed, hereditary nonpolyposis CRC can be caused by mutations in mismatch repair genes, such as MSH2 and MLH1,68,69 collectively termed the caretakers of genome integrity.71 The DNA repair defects lead to mutations in cancer-causing genes, such as adenomatous polyposis coli (APC).72
X. PRE-GENES, GENES, EPIGENES, AND THE CAN/DE-CAN DYNAMICS
I use the term pre-gene for DNA response elements that bind with specific ligands to set the stage for gene activation, gene silencing, or modifiucation of gene behavior. I use the term epigene for components of the genetic machinery — histone proteins and others — that are essential for the structural and functional integrity of genes. Needless to emphasize, the prevailing oxygen conditions govern the biologic activities of all pre-genes, genes, and epigenes in all cases in such relationships have been explored. For example, it is established that hypoxia alters the functionalities of a very large number of physiologically important genes and gene products,43,44,73-79 including:
Increased production of erythropoietin, a hormone required for the formation of red blood cells. An increase in the number of erythrocytes enhances the delivery of oxygen to tissues.
Increased generation of vascular endothelial growth factor (VEGF) is a key regulator of blood vessel growth (angiogenesis). The induction of VEGF expression in hypoxic tissues results in enhanced blood flow, thereby providing protection against ischemic injury. VEGF is also important for tumor angiogenesis.
Up-regulation of tyrosine hydroxylase. Increased activity of this enzyme in glomus cells of the carotid body in the neck enables the hypoxic animal to achieve a sustained increase in ventilation.
Increased synthesis of certain glycolytic enzymes, enabling intracellular levels of the energy-rich molecule adenosine triphosphate to be maintained.
FixL in Rhizobium bacteria, a heuristic distant relative of PAS family members, is an oxygen-sensing fusion protein containing a heme binding domain and a protein kinase domain.
Generation of HIFa to pVHL, which mediates the assembly of a complex (UL) that activates the ubiquitin-E3 ligase.
HIF is also activated by the transition metal cations Co2+, Ni2+, and Mn2+ and also by reagents that chelate iron. These observations hint that HIFa might be oxidatively modified by reactive oxygen species generated through a nonenzymatic oxygen- and iron-dependent process akin to that previously described for both bacterial and mammalian enzymes.
Other oxygen sensors include flavoheme oxidoreductases, such as cytochrome b5/b5 reductase fusion protein. An NADPH (reduced form of nicotinamide adenine dinucleotide phosphate) oxidase containing GP91PHOX behaves as an oxygen sensor in pulmonary neuroepithelial bodies.
Pulmonary neuroepithelial bodies are broncho-chemoreceptors that express the O(2) sensor protein NADPH oxidase and O(2)-sensitive K(+) channels K(+)(O(2)). Although there is a consensus that redox modulation of K(+)(O(2)) may be a common O(2)-sensing mechanism, the identity of the O(2) sensor and related coupling pathways are still controversial.
Hypoxia inhibits K channel current.
p53 and Oxygen Dynamics
In cancer genomics, p53 gene dynamics have drawn the most interest.80-84 Human tumors growing in mice treated with a single antiangiogenesis drug initially shrink but begin to grow again after periods of few to several weeks. (One would not expect otherwise in view of Nature’s preoccupation with complementarity and Contrariety). The cells within a single tumor in that setting vary in their ability to withstand hypoxic conditions. Specifically, the loss of p53 in tumor cells confers upon them a resistance to low-oxygen environment. In experiments with mixtures of p53+/+ and p53-/- cells in equal proportions, the p53+/+ cells have a tendency to cluster in close vicinity of blood vessels (high-oxygen environment) while such cells succumb to apoptosis in hypoxic regions relatively distant from the vessels. In contrast, very few p53-/- cells died of such cellular suicide in hypoxic regions. (See the chapter entitled, “Apoptosis: The Oxidative-Dysoxygenative Perspective” for further discussion of the impact of oxidosis and dysoxygenosis on programmed cellular demise). Regrettably—but not unexpectedly, in my view—such observations cast dark shadows on the previously optimistic view that the problem of cancer could be solved by targeting genetically stable cells which support malignant cells, i.e., endothelial cells that sprout to form new capillaries to maintain the increasing demands of growing cancers.
There is considerable—and rapidly enlarging —genetic evidence for my hypothesis of cancerization of non-cancer cells and of de-cancerization of cancer cells. I include here some consideration of the effects of p53 and Bcl genes on apoptosis of cancer cells to support my hypothesis.
The pro-apoptotic roles of p53 genes and the anti-apoptotic roles of Bcl-2 genes require some comment. The p53 gene is a tumor-suppressing gene and its expression is required for apoptosis. It is known that tumor cells that are resistant to apoptosis lack the expression of p53. Bcl-2 plays an opposing role. Neoplastic cells that overexpress Bcl-2 are also resistant to apoptosis. For that consideration, Bcl is sometimes referred to as an apoptotic-suppressor protein. Expression of both genes is regulated by the prevailing oxyecologic conditions in the tumor. I cite here the following two specific examples: (1) the tumor oxygenation state was found to predict the likelihood of distant metastases in human soft tissue sarcoma; and (2) the degree of tumor hypoxia has been associated with malignant progression in advanced cancer of the uterine cervix. I might add here that in some other studies high-resolution measurements of interstitial pH and pO2 gradients in solid tumors in vivo failed to reveal a similar correlation.
XI. APOPTOSIS AND THE CAN/DE-CAN DYNAMICS
Apoptosis is believed to be one of the physiological processes the body uses to eradicate cancer cells. It is often referred to as “cell suicide.”85 (See Nature’s Preoccupation with Complementarity and Contrariety, the first volume of The Principles and Practice of Integrative Medicine,86 for an in-depth discussion of apoptosis.) It is stated that when a cell recognizes that its mutated DNA is beyond repair—or is energetically too expensive to fix—it self-destructs, following some internal clues. Apoptosis has been sharply contrasted with cell death by necrosis.87-90 Necrosis is believed to be caused by external elements acting upon a cell. The dissolution of the cell membrane in necrosis results in escape of dead and dying cellular innards into the local microenvironment, which evokes an inflammatory response which, in turn, inflicts further cellular damage. By contrast, a pre-programmed cellular death by apoptosis does not release its inflammatory and toxic contents into matrix and cells surrounding it.
There is something amusing about this simplistic distinction between cell death by apoptosis and necrosis. Having first stated that apoptosis is an internally directed phenomenon without external cues, most writers then go on to contradict themselves and describe how altered expressions of certain genes block or promote apoptosis. I have discussed this subject at length in Nature’s Preoccupation With Complementarity and Contrariety, the first volume of The Principles and Practice of Integrative Medicine. 85 In this section, I limit myself to some aspects of physiological and altered expressions of p53 and Bcl genes that profoundly affect apoptosis.
The literature on the subject of apoptosis—the so-called programmed cell death—in cancer is of profound significance in the can/de-can dynamics of the dysox model of cancer. I have presented the morphologic, genetic, and molecular aspects of apoptosis at length in Nature’s Preoccupation. The major molecular pathways include the following: (1) interaction of CD95 (death receptor) with CD95-L (death ligand); (2) Bcl-2 family of proteins with central roles in intracellular apoptotic signal transduction; (3) adapter protein Apaf-1 (apoptotic protease activator factor-1); (4) caspase family of proteolytic enzymes; (5) DNA damage sensors and P53 dynamics; and (6) mitochondrial events that initiate and/or amplify intracellular oxidosis.87-90 It is generally assumed that the phenomena that initiate all of the above pathways (upstream events) are obscure. In Nature’s Preoccupation, I marshal evidence for my view that all initial events that lead to apoptosis are oxygen-regulated, both by positive and negative feedback mechanisms.
XII. WHY DOESN’T EVERYONE HAVE CANCER? THE DNA-DAMAGE RESPONSE
Why doesn’t everyone have cancer? That is a legitimate question given the vulnerability of trillions of cells susceptible to gene mutations that could spark uncontrolled cell proliferation and clinical cancers. It has long been suspected that normal cells must have some robust mechanisms that can perceive the mutational damage and arrest aberrant cycles of cell divisions triggered by oncogenic stimuli.91 Experimental evidence for that view, however, was lacking until very recently when Bartkova et al.92 and Gorgoulis et al.93 published evidence for the existence of the phenomenon of DNA-damage response (DDR). Specifically, it was demonstrated that oncogene-driven cell-division cycles trigger DNA damage associated with DNA replication. That DNA-damage associated response raises a barrier to sustained cellular proliferation and the developmental of malignant tumors. Thus, progression towards clinical cancer requires the wayward cell to inactivate the mechanisms that monitor damage during DNA replication. Those findings help explain the close link between genomic instability and cancer evolution. Several genes are involved in DDR, including p53, ATM, ATR, Chk2, Fanconi anaemia proteins and the breast-cancer- susceptibility proteins BRCA1 and BRCA2.
How is that crucial DNA-damage response triggered and maintained? Direct experimental evidence implicating altered oxyecologic conditions in DDR is not yet forthcoming. However, it is note worthy in this context that oxidative stress is known to both interefere with tumor suppressive gene functions and trigger oncogenic elements. In previous columns on oxygen homeostasis, I have marshalled extensive evidence for my view that unrelenting oxidative stress exerts its pathogenic influences essentially through disruption of oxygen homeostasis. Thus, it seems safe to predict that the direct role of the oxyecologic conditions in DDR will be established with future investigations into this field.
XIII. ANGIOGENESIS AND THE CAN/DE-CAN DYNAMICS
There has been intense interest in recent years about the characterization, biology, and possibility of curing cancer with anti-angiogenesis drugs, such as angiostatin and endostatin.94-100 Consider the following quote from a front page article in The New York Times of May 3, 1998:
Judah is going to cure cancer in 2 years….Dr. Watson said that Dr. Folkman would be remembered along with scientists like Darwin as someone who permenently altered civilization.
Needless to point out, the Times was plainly wrong. But why would any Times reporter act so callously and raise false hopes of millions of cancer patients? The following quote from a commentary published in Science o (1998;250:996)concerning the Times’s story cited above sheds some light:
Shortly after Kolata’s story ran, other journalists discovered that Kolata’s literary agent, John Brockman, was floating a proposal for a book about the research, reportedly asking for an advance of $2 million.
Concerning angiogenesis, it seems safe for me to make the following two predictions in light of the material presented in this article:
1. First, with time some anti-angiogenic drugs — related to angiostatin and endostatin or belonging to other classes of compounds — will be discovered that will control certain forms of cancer for variable periods of time; and
2. Second, none of those drugs will yield good long-term clinical results, let alone ‘cure’ cancer.
The basis of my prediction is simple: none of the anti-angiogenesis drugs by itself can be expected to alter the deranged oxyecologic conditions of cancer cells and non-cancer cells in their vicinity.
The subject of angiogenesis inhibitors in the body is vast.94-100 To provide the reader a sense of the range of molecular moieties that promote angiogenesis and those that inhibit angiogenesis, I have posted a list of those compounds on http://www.majidali.com.
When or how does the transition of a tumor to an angiogenic state occur? Limited experimental data sheds light on this important question. In the transgenic mouse model, animals expressing an oncogene in the beta cells of the pancreatic islets heritably recapitulated a progression from normality to hyperplasia to neoplasia. The angiogenic activity first appears in a subset of hyperplastic islets before the onset of tumor formation. A novel in vitro assay confirms that hyperplasia per se does not obligate angiogenesis. Rather, a few hyperplastic islets become angiogenic in vitro at a time when such islets are neovascularized in vivo and at a frequency that correlates closely with subsequent tumor incidence. These findings suggest that induction of angiogenesis is an important step in carcinogenesis.
THE SUN-SOIL MODEL FOR THE CAN/DE-CAN DYNAMICS
For integrative management of persons with cancer, I use the “Dysox, Detox, and Reox” strategy. Dysox, as mentioned earlier, stands for dysoxygenosis. I reiterate here that the three furies of cancer—acidosis, oxidosis, and dysoxygenosis — are the primary culprits in all destructive effects of cancer, local, systemic, and metastatic. In this article, I have attempted to summarize a very large body of clinical, histologic, biochemical, and experimental evidence to support that. I use the term detox for detoxification in the broader sense of restoring oxygen homeostasis, redox equilibrium, and acid-base balance by addressing all tissue-organ ecosystems of the body, with a special focus on the bowel, blood, and liver ecosystems. Reox is the term I use for patient education for an integrative approach to the global goal of re-oxygenation of all cellular systems of the body.
In the sun-soil model of dysox-to-detox-to-reox, the sun symbolizes the spiritual dynamics of healing, whereas the soil is represented by the trio of the bowel, blood, and liver ecosystems. The clinical applications of the sun-soil model for treating cancer will be the subject of a subsequent article on the subject. of broad his subject is sufficiently broad to deserve a follow-up article in this series.
XIV. CLOSING COMMENTS
In this article, I marshal evidence for my view that the metabolic conditions of a cancer cell (oxidosis, acidosis, and dysoxygenosis) create similar conditions in a non-cancer cell in its vicinity—a cancer cell cancerizes a non-cancer cell, so to speak. Furthermore, the metabolic conditions in a normal cell seek to oppose the metabolic characteristics of a cancer cell in a way that threatens the survival of the cancer cell—a normal cell de-cancerizes the cancer cell, so to speak. I draw evidence for that view from clinical, biochemical, morphologic, and genetic studies. I have especially focused on the dynamics of hypoxia-inducible factor, hypoxia-induced activiation of oncogenes (such as MET gene) and hypoxia-mediated suppression of tumor suppressor genes, such as p53. The main conclusion I draw from that evidence is that no therapeutic plans for cancer can be considered complete unless it sharply focuses on all aspects of the cancerization/de-cancerization dynamics of the oxyecologic conditions of the tumor/host interactions.
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