A Hypothesis Concerning the Biphasic Dose-response of Tumors to Angiostatin and Endostatin.

This manuscript proposes a hypothesis to explain the U-shaped dose-response observed for angiostatin and other high-molecular-weight drugs in various anti-cancer bio-assays. The dose-response curves for angiostatin and endostatin (measured as suppression of tumor growth) go through an optimum (i.e., minimum tumor growth) and then becomes less effective at higher doses. The literature suggests that at lower doses the primary action of these high-molecular-weight drugs is to counteract the angiogenic effects of vascular endothelial growth factor (VEGF). To do this, the drugs must pass out of the blood vessel and enter the extra-cellular matrix (ECM) where VEGF induces the growth and fusion of tip cells. Ironically, VEGF actually facilitates access of the drugs to the ECM by making the vascular endothelium leaky. At higher doses, the high-molecular-weight drugs seem to reverse VEGF-induced permeability of the endothelium. Thus, at high dose rates, it is hypothesized that the drugs are not able to enter the ECM and block the angiogenic effects of VEGF there. As a result, high doses of the drugs do not suppress vascularization of the tumor or tumor growth. Moreover, if the permeability of the vessels is suppressed, the VEGF released by the stroma is concentrated in the ECM where it amplifies the angiogenic activity around the tumor.

Historical perspective of cell-cell fusion in cancer initiation and progression.

This review discusses the topic of cell-cell fusion as it related to cancer causation, progression and metastasis. The relevant time period is over a century of research and analysis from the observation and hypothesis of Theodor Boveri in circa 1902 to the most recent publications in 2012. There are three main intertwined thrusts in this history: (i) progress in our overall understanding of cancer and the relative importance of mutations and aneuploidy; (ii) evidence that cell-cell fusion occurs and leads to aneuploidy in somatic cells, especially that cell-cell fusion allows rapid evolution of cancer cells that, most importantly, acquire a repertoire of traits from bone marrow-derived cells that facilitate metastasis; and (iii) evidence that viruses catalyze cell-cell fusion and that aneuploidy evolving from the hybrid cells is an important if not the principal basis for the association of viruses with certain cancers. There have been many competing hypotheses concerning all aspects of cancer development during this time period. Overall, the cell-cell fusion hypothesis has never gained preeminence. As a result, it has gone through long periods of obscurity only to be re-discovered because new supportive data appeared. Technical advances (especially in our ability to sequence genomes and establish the evolution of cell clones through cytogenetics) have recently made tools available that could help elucidate the role of cell-cell fusion, aneuploidy and viruses in cancer. Evidence seems to be increasing in support of the ideas stated by Boveri a century ago.

Proteasome inhibition with bortezomib: an effective therapy for severe antibody mediated rejection after renal transplantation.

Antibody-mediated rejection (AMR) following renal transplantation is less responsive to conventional anti-rejection therapies. Plasmapheresis (PP), intravenous immunoglobulin (IVIg), rabbit antithymocyte globulin (rATG) and rituximab deplete immature B-cells but not mature plasma cells. The proteasome inhibitor bortezomib has activity against mature plasma cell, the source of damaging donor-specific antibody (DSA).We present the successful use of bortezomib in 2 patients who developed AMR following kidney transplantation. The first patient was a 54-year-old white female who received living-unrelated kidney transplantation from her husband. She developed severe AMR early after transplantation with rising DSA titers consistent with an anamnestic immune response by memory cells to the donor antigens. Renal function deteriorated despite treatment with pulse methylprednisolone (MP), PP and IVIg. After initiation of therapy with bortezomib, DSA titers became negative and serum creatinine returned to baseline with histological resolution of AMR. The second patient was a 19-year-old white male who received deceased donor kidney transplantation and developed AMR within 2 weeks, refractory to therapy with pulse MP, PP and IVIg with rising DSA. Bortezomib use resulted in disappearance of DSA and renal function improvement. Both patients tolerated the treatment well with stable renal function at last follow-up. The novel mechanisms of action and preliminary results with bortezomib are encouraging, but require larger studies and longer follow-up.

Two Endogenous Antiangiogenic Inhibitors, Endostatin and Angiostatin, Demonstrate Biphasic Curves in their Antitumor Profiles.

Angiogenesis refers to growth of blood vessels from pre-existing ones. In 1971, Folkman proposed that by choking off the blood supply to tumors, they are starved, leading to their demise. A few years ago, the monoclonal antibody Avastin became the first antiangiogenic biological approved by FDA, for treatment of cancer patients. Two other antiangiogenic endogenous protein fragments were isolated in Folkman's laboratory more than a decade ago. Here, we present a short review of data demonstrating that angiostatin and endostatin display a biphasic antitumor dose-response. This behavior is common among a large number of antiangiogenic agents and the reduced effectiveness of antiangiogenic agents at high dose rates may be due to suppression of growth of new vessels carrying the agent into the critical region around the tumor.

Developmental diseases and the hypothetical Master Development Program.

Small deletions and duplications frequently occur in the pericentromeric region of chromosomes and many of these are associated with developmental abnormalities. These developmental syndromes are conventionally attributed to abnormal expression of protein-coding genes in the affected region. A hypothesis has recently been published concerning a Master Development Program based on noncoding transcripts from these regions (Parris GE. A hypothetical Master Development Program for multi-cellular organisms: Ontogeny and phylogeny. Biosci Hypotheses 2009;2:3-12.). This paper summarizes and expands the recently published hypothesis to include it application to developmental diseases. The author proposes that development of multi-cellular organisms is guided by a Master Development Program (MDP) located primarily in the pericentromeric heterochromatin. The MDP is believed to consist of a series of Generation-Specific Control Keys (GSCK) transcribed in sequence by Ikaros family transcription factors unless the GSCKs are suppressed by Sall1-family or Dnmt3b-family proteins. The MDP is proposed to increment with each cell cycle to the next GSCK resulting in development of the clone. A clone may be programmed to split into two clones as necessary through a two-cycle mitosis processes. The transcripts of the GSCKs presumably yield noncoding nuclear messenger RNAs (nmRNAs, 8-30 nt units) that act directly (e.g., as primers for RNA polymerase II) and indirectly to regulate HOX and other high-level transcription factor and developmental genes. As envisioned, the MDP would evolve by terminal addition of new GSCKs. The new GSCKs are produced by evolutionary consolidation of retro-transcripts into pyknons that collect and evolve at the end of the pericentromeric heterochromatin and are eventually incorporated into the MDP. The retro-transcripts are though to be produced during episodic retrovirus epidemics and account for punctuated equilibrium in species evolution.

Effects of assertiveness training and expressive writing on acculturative stress in international students: A randomized trial.

International university students often experience acculturative stress, and culturally appropriate techniques to manage stress are needed. This randomized trial tested the effects of group assertiveness training, private expressive writing, their combination, and a wait-list control on the acculturative stress, affect, and health of 118 international students at an urban North American university. Interventions were conducted at the start of a semester, and assessments were conducted at baseline and at the end of the semester. Group assertiveness training was rated positively by students and led to lower negative affect, whereas expressive writing was less well received and led to higher homesickness and fear, but also to higher positive affect. The combined intervention had no effects, perhaps because the 2 components negated each other. It is concluded that group assertiveness training improves emotional adjustment of international students but that expressive writing has mixed effects and needs further development and study. (PsycINFO Database Record

2-deoxy-D-glucose as a potential drug against fusogenic viruses including HIV.

Most enveloped viruses fuse with host cells and catalyze fusion among host cells by expression of specific patterns of N-glycosylation on their envelope proteins. In the 1970s, it was observed that 2-deoxy-D-glucose (2DOG) and 2-fluoro-2-deoxy-D-mannose (2F2DOM) inhibited N-glycosylation of asparagine (Asn) sites on the external domain of viral envelope proteins. This effect led to the virus particles being non-fusogenic with greatly reduced infectivity and reduced ability to pass from cell to cell by catalyzing cell--cell fusion. At that time, this observation was not particularly important because viral diseases were readily prevented by vaccines and there was no known link between fusogenic viruses and cancer. Today, we are faced with a chronic and lethal viral disease (AIDS) caused by a virus (HIV) that mutates so quickly that we have not been able to produce a vaccine. Moreover, it is spreading among millions of people unable to afford more than basic medications. In addition, cell--cell fusion has been identified as an important, if not essential, step in the progression of abnormal cell clones to clinically significant cancer and fusogenic viruses have been shown to cause progression of some tumors. Here, we reiterate the hypothesize (first made in 1986 by Blough et al. [Blough HA, Pauwels R, De Clercq E, Cogniaux J, Sprecher-Goldberger S, Thiry L. Glycosylation inhibitors block the expression of LAV/HTLV-III (HIV) glycoproteins. Biochem Biophys Res Commun 1986; 141:33-8]) that 2DOG, 2F2DOM and related compounds, which interfere with normal N-glycosylation of virus envelope proteins, are attractive candidates for anti-fusogenic drugs that can be used against chronic virus diseases and cancers. This analysis also supports the concept of blocking N-acetylglucosaminyl-transferases with chloroquine or other drugs (proposed by Savarino et al. [Savarino A, Lucia MB, Rastrelli E et al. Anti-HIV effects of chloroquine: inhibition of viral particle glycosylation and synergism with protease inhibitors. J Acquir Immune Defic Syndr 2004; 35:223-32]) as an anti-viral approach. These drugs may have broader utility and lower cost than drugs designed specifically to target the gp41 protein of HIV, which have become popular as viral-entry inhibitors for treatment of HIV/AIDS.

Why G3139 works poorly in cancer trials but might work well against HIV.

The antisense drug G3139 (oblimersen sodium, Genta, Inc.) is a phosphorothioate oligodeoxynucleotide (ODN) containing unmethylated CpG units, which is targeted to suppress Bcl-2. To date, its effectiveness in cancer clinical trials has been minimal. Some suggestions are provided for that disappointment and recent citations are provided that support the idea that G3139 may be effective at clearing viral infections, specifically HIV. At the time G3139 was conceived as an anti-cancer drug candidate, it was viewed optimistically because Bcl-2 was widely believed to be the most important protein blocking p53-dependent apoptosis caused by internal stress. Since that time, we have learnt that Bcl-2 is not the only protein that inhibits apoptosis and that p53 itself is frequently malfunctioning in tumors. Thus, the anti-cancer utility of suppressing Bcl-2 in cancer cells is limited. Moreover, Bcl-2 has a role in halting the cell cycle (though p27), which may slow down tumor growth; and Bcl-2 even has pro-apoptotic roles in the execution of apoptosis initiated by external death signals (via Fas/CD95 and caspase 3). Overall, in the clinical setting, G3139 usually has statistically significant but medically unimportant benefit. These results have greatly diminished the enthusiasm for the drug especially when the side effects are considered. Specifically, the unmethylated CpG ODN (and/or the phosphorothioate group) activates the immune system, but this potentially important anti-cancer effect is lost when the immune cells undergo premature apoptosis apparently because their Bcl-2 levels have been lowered by the antisense effect of G3139. While this effect on immune cells is usually undesirable, it is exactly what would be useful for activating immune cells, initiating provirus transcription in retrovirus-infected cells, and facilitating selective apoptosis of these infected cells. In general, G3139 might have benefit in clearing chronic infections by intracellular parasites including viruses (HIV, SIV, HTLV, HBV, coronavirus, etc.). Indeed, G3139 has been shown to cause apoptosis in EBV-infected cells leading to clearance of the virus.

Mechanism and history of evolution of symbiotic HIV strains into lethal pandemic strains: the key event may have been a 1927 trial of pamaquine in Leopoldville (Kinshasa), Congo.

In previous papers, I have rejected both the zoonosis and the serial transfer hypotheses of the origin and evolution of the current lethal pandemic strains of HIV. The hypothesis that fits the critical observations is that all the human and nonhuman primate species in central Africa (an area of hyper-endemic malaria) have shared (through inter-species transfers) a "primate T-cell retrovirus" (PTRV), which has adapted to each host species. This retrovirus is believed to assist primate T-cells attack the liver stage of the malaria infection. Each geographic region has a dominant primate host and a characteristic virus. Starting in 1955 and continuing into the late 1970s, chloroquine was provided by the WHO and used for prophylaxis against malaria. Chloroquine has a number of biochemical activities but two of the most important are blocking transcription of cellular genes and proviruses activated by NF-kappaB and blocking the glycosylation of surface proteins on viruses and cells. Concurrent with the development of resistance of the malaria parasite to chloroquine, HIV strains were quickly selected, which have enhanced transcription rates (by inclusion of multiple kappaB binding sites in their long terminal repeats by recombination) and enhanced infectivity (fusogenicity) (most likely by mutations in multiple viral genes that regulate glycosylation of Env). There also may have been mutations that enhanced activation of NF-kappaB in the host cell. These changes in the retrovirus genome were not manifest in effects of the HIV strains as long as the hosts were under the influence of chloroquine. But, when the virus infects people who are not protected by chloroquine, the virus multiplies more rapidly and is more communicable. Fortunately, most of these strains (i.e., HIV-2 groups, and HIV-1 O and HIV-1 N) self-regulate (i.e., infected cells kill infected cells) well enough that viral loads remain subdued and bystander cells of the immune system are not excessively attrited. In the case of HIV-1 group M, however, there is more going on. Following the work of Korber et al. on the phylogenetics of HIV-1 groups M, I reach the conclusion that the major subgroups giving rise to the worldwide pandemic, were founded in a 1927 clinical trial of pamaquine (plasmoquine) in Leopoldville (Kinshasa). This drug is much more toxic that chloroquine and appears to have strongly selected for resistance to apoptosis in infected cells, which allows these subgroups to attrite bystander cells leading to AIDS.

AIDS: caused by development of resistance to drugs in a non-target intracellular parasite.

The origin of acquired immune disorder syndrome (AIDS) has been the subject of substantial controversy both in the scientific community and in the popular press. The debate involves the mode of transmission of a simian virus (SIV) to humans. Both major camps in the argument presume that humans are normally free of such viruses and assume that once the simian virus was transmitted, it immediately infected some T-cells and caused the release of toxic agents that killed off bystander (uninfected) T-cells resulting in AIDS. The evolution of the Simian virus (SIV) into a human virus (HIV) is regarded as an artifact. In contrast, a fundamentally different hypothesis has been proposed [Parris GE. Med Hypotheses 2004;62(3):354-7] in which it is presumed that in hyper-endemic areas of malaria (central Africa), all primates (humans and non-human primates) have shared a retrovirus that augments their T-cell response to the malaria parasite. The virus can be called "primate T-cell retrovirus" (PTRV). Over thousands of years the virus has crossed species lines many times (with little effect) and typically adapts to the host quickly. In this model, AIDS is seen to be the result of the development of resistance of the virus (PTRV) to continuous exposure to pro-apoptotic (schizonticidal) aminoquinoline drugs used to prevent malaria. The hypothesis was originally proposed based on biochemical activities of the aminoquinolines (e.g., pamaquine (plasmoquine(TM)), primaquine and chloroquine), but recent publications demonstrated that some of these drugs definitely adversely affect HIV and other viruses and logically would cause them to evolve resistance. Review of the timeline that has been created for the evolution of HIV in humans is also shown to be qualitatively and quantitatively consistent with this hypothesis (and not with either version of the conventional hypothesis). SARS and Ebola also fit this pattern.

The cell clone ecology hypothesis and the cell fusion model of cancer progression and metastasis (II): three pathways for spontaneous cell-cell fusion and escape from the intercellular matrix.

The two-stage initiation-progression model of cancer is widely accepted. Initiation appears to result most often from accumulation of damage to the DNA expressed as multiple mutations in the phenotype. Unsymmetrical chromosome segregation during mitosis of normal or mutated cells produces aneuploid cells and also contributes to the evolution of neoplasia. However, it has been pointed out (Parris GE. Med Hypotheses 2005;65:993-4 and 2006;66:76-83) that DNA damage and loss of chromosomes are much more likely to lead the mutant clones of cells to extinction than to successful expansion (e.g., an example of Muller's Ratchet). It was argued that aneuploid neoplasia represent new parasite species that successfully evolve to devour their hosts by incorporating sex-like redistribution of chromosomes through spontaneous or virus-catalyzed cell-cell fusion into their life-cycle. Spontaneous cell-cell fusion is generally blocked by the intercellular matrix to which the cells are bound via surface adhesion molecules (frequently glycoproteins, e.g., CD44). In order for progression of matrix-contained neoplasia toward clinically significant cancer to occur, the parasite cells must escape from the matrix and fuse. Release from the matrix also allows the parasite cells to invade adjacent tissues and metastasize to remote locations. Both invasion and metastasis likely involve fusion of the migrating parasite cells with fusion-prone blast cells. There are at least three pathways through which parasite cells can be liberated from the confining matrix: (i) Their adhesion molecules may be modified (e.g., by hyper-glycosylation) so that they can no longer grip the matrix. (ii) Their adhesion molecules or matrix may be saturated with other ligands (e.g., polyamines). (iii) Their adhesion molecules may be cleaved from the cell surface or the matrix itself may be cleaved (e.g., by MMPs or ADAMs). It is hypothesized that mobilization of parasite cells and cell-cell fusion go hand-in-hand in the progression of neoplasia to clinically significant cancer through invasion and metastasis. The latency between tumor recognition and exposure to mutagens and the increased incidence of cancer with age can probably be related to slow breakdown of the intercellular matrix that provides a barrier to cell-cell fusion.