Extracellular vesicles in gastrointestinal cancer in conjunction with microbiota: On the border of Kingdoms.

Extracellular vesicle (EV) production is a universal feature of metazoan cells as well as prokaryotes (bMVs - bacterial microvesicles). They are small vesicles with phospholipid membrane carrying proteins, DNA and different classes of RNAs and are heavily involved in intercellular communication acting as vectors of information to target cells. For the last decade, the interest in EV research has exponentially increased though thorough studies of their roles in various pathologies that was not previously possible due to technical limitations. This review focuses on research evaluating the role of EV production in gastrointestinal (GI) cancer development in conjunction with GI microbiota and inflammatory diseases. We also discuss recent studies on the promising role of EVs and their content as biomarkers for early diagnosis of GI cancers. The bMVs have also been implicated in the pathogenesis of GI chronic inflammatory diseases, however, possible role of bMVs in tumorigenesis remains underestimated. We propose that EVs from eukaryotic cells as well as from different microbial, fungi, parasitic species and edible plants in GI tract act as mediators of intracellular and inter-species communication, particularly facilitating tumor cell survival and multi-drug resistance. In conclusion, we suggest that matching sequences from EV proteomes (available from public databases) with known protein sequences of microbiome gut bacteria will be useful in identification of antigen mimicry between evolutionary conservative protein sequences. Using this approach we identified Bacteroides spp. pseudokinase with activation loop and homology to PDGFRα, providing a proof-of-concept strategy. We speculate that existence of microbial pseudokinase that 'mimics' PDGFRα may be related to PDGFRα and Bacteroides spp. roles in colorectal carcinogenesis that require further investigation.

Significantly reduced CCR5-tropic HIV-1 replication in vitro in cells from subjects previously immunized with Vaccinia Virus.

BACKGROUND: At present, the relatively sudden appearance and explosive spread of HIV throughout Africa and around the world beginning in the 1950s has never been adequately explained. Theorizing that this phenomenon may be somehow related to the eradication of smallpox followed by the cessation of vaccinia immunization, we undertook a comparison of HIV-1 susceptibility in the peripheral blood mononuclear cells from subjects immunized with the vaccinia virus to those from vaccinia naive donors. RESULTS: Vaccinia immunization in the preceding 3-6 months resulted in an up to 5-fold reduction in CCR5-tropic but not in CXCR4-tropic HIV-1 replication in the cells from vaccinated subjects. The addition of autologous serum to the cell cultures resulted in enhanced R5 HIV-1 replication in the cells from unvaccinated, but not vaccinated subjects. There were no significant differences in the concentrations of MIP-1alpha, MIP-1beta and RANTES between the cell cultures derived from vaccinated and unvaccinated subjects when measured in culture medium on days 2 and 5 following R5 HIV-1 challenge. DISCUSSION: Since primary HIV-1 infections are caused almost exclusively by the CCR5-tropic HIV-1 strains, our results suggest that prior immunization with vaccinia virus might provide an individual with some degree of protection to subsequent HIV infection and/or progression. The duration of such protection remains to be determined. A differential elaboration of MIP-1alpha, MIP-1beta and RANTES between vaccinated and unvaccinated subjects, following infection, does not appear to be a mechanism in the noted protection.

Induction of autophagy by anthrax lethal toxin.

Autophagy is an evolutionary conserved intracellular process whereby cells break down long-lived proteins and organelles. Accumulating evidences suggest increasing physiological significance of autophagy in pathogenesis of infectious diseases. Anthrax lethal toxin (LT) exerts its influence on numerous cells and herein, we report a novel effect of LT-induced autophagy on mammalian cells. Several autophagy biochemical markers including LC3-II conversion, increased punctuate distribution of GFP-LC3 and development of acidic vesicular organelles (AVO) were detected in cells treated with LT. Analysis of individual LT component revealed a moderate increase in LC3-II conversion for protective antigen-treated cells, whereas the LC3-II level in lethal factor-treated cells remained unchanged. In addition, our preliminary findings suggest a protective role of autophagy in LT intoxication as autophagy inhibition resulted in accelerated cell death. This study presents a hitherto undescribed effect of LT-induced autophagy on cells and provides the groundwork for future studies on the implication of autophagy in anthrax pathogenesis.

The effects of antiviral treatment on breast cancer cell line.

BACKGROUND: Recent studies have revealed the positive antiproliferative and cytotoxic effects of antiviral agents in cancer treatment. The real effect of adjuvant antiviral therapy is still controversial due to the lack of studies in biochemical mechanisms. Here, we studied the effect of the antiviral agent acyclovir on morphometric and migratory features of the MCF7 breast cancer cell line. Molecular levels of various proteins have also been examined. METHODS: To evaluate and assess the effect of antiviral treatment on morphometric, migratory and other cellular characteristics of MCF7 breast cancer cells, the following experiments were performed: (i) MTT assay to measure the viability of MCF7 cells; (ii) Colony formation ability by soft agar assay; (iii) Morphometric characterization by immunofluorescent analysis using confocal microscopy; (iv) wound healing and transwell membrane assays to evaluate migration and invasion capacity of the cells; (v) ELISA colorimetric assays to assess expression levels of caspase-3, E-cadherin and enzymatic activity of aldehyde dehydrogenase (ALDH). RESULTS: We demonstrate the suppressive effect of acyclovir on breast cancer cells. Acyclovir treatment decreases the growth and the proliferation rate of cells and correlates with the upregulated levels of apoptosis associated cytokine Caspase-3. Moreover, acyclovir inhibits colony formation ability and cell invasion capacity of the cancer cells while enhancing the expression of E-cadherin protein in MCF7 cells. Breast cancer cells are characterized by high ALDH activity and associated with upregulated proliferation and invasion. According to this study, acyclovir downregulates ALDH activity in MCF7 cells. CONCLUSIONS: These results are encouraging and demonstrate the possibility of partial suppression of cancer cell proliferation using an antiviral agent. Acyclovir antiviral agents have a great potential as an adjuvant therapy in the cancer treatment. However, more research is necessary to identify relevant biochemical mechanisms by which acyclovir induces a potent anti-cancer effect.

Weight change therapy as a potential treatment for end-stage ovarian carcinoma.

PATIENT: Female, 41 FINAL DIAGNOSIS: Ovarian carcinoma Symptoms: Ascites • hepatomegaly • weight loss MEDICATION: - Clinical Procedure: - Specialty: Oncology. OBJECTIVE: Unusual or unexpected effect of treatment. BACKGROUND: The aim of this case report is to present the results of treatment of end-stage ovarian carcinoma in a 41-year-old women using weight loss therapy. CASE REPORT: We describe the case of a female aged 41 years with epithelial invasive ovarian cancer of III-IV stage, T3N2M1. Concurrent diseases were: abdominal carcinomatosis; hepatomegaly; ascites; condition after laparocentesis and skin-abdominal fistula; condition after 6 courses of neo-adjuvant polychemotherapy; hypertension II stage, risk factor of 3-4; dyslipidemia; and metabolic syndrome. A weight loss method based on a very-low-calorie diet and physical activity was used. Body weight was reduced from 74 kg to 53 due to loss of adipose tissue after 6 months of therapy. At the same time, the percentages of water and muscle tissue were increased significantly. While overweight was reducing, clinical, laboratory, and instrumental results were improving. As a result of the weight loss therapy, about ≈100 mm-sized ovarian cancer was transformed into smaller-sized ovarian cysts. CONCLUSIONS: An analgesic effect was also achieved without use of narcotic or non-narcotic analgesics. These cyto-reversible processes were documented by laboratory and instrumental data. The mechanisms behind these differences remain to be elucidated. Future research with a larger study cohort and longer follow-up is needed to further investigate the role of caloric restriction diet in cancer cell changes in ovarian cancer.

Implication of human herpesviruses in oncogenesis through immune evasion and supression.

All human herpesviruses (HHVs) have been implicated in immune system evasion and suppression. Moreover, two HHV family members, i.e. EBV and KSHV, are recognised as oncogenic viruses. Our literature review summarises additional examples of possible oncogenic mechanisms that have been attributed to other HHVs. In general, HHVs affect almost every cancer-implicated branch of the immune system, namely tumour-promoting inflammation, immune evasion, and immunosuppression. Some HHVs accomplish these effects by inhibiting apoptotic pathways and by promoting proliferation. Mechanisms related to immunosupression and low grade chronic inflammation could eventually result in the initiation and progression of cancer. In this article we open a discussion on the members of Herpesviridae, their immune evasion and suppression mechanisms, and their possible role in cancer development. We conclude that discerning the mechanisms of interplay between HHV, immune system, and cancer is essential for the development of novel preventative and therapeutic approaches for cancer treatment and prophylaxis.

Disruption of Bcl-2 and Bcl-xL by viral proteins as a possible cause of cancer.

The Bcl proteins play a critical role in apoptosis, as mutations in family members interfere with normal programmed cell death. Such events can cause cell transformation, potentially leading to cancer. Recent discoveries indicate that some viral proteins interfere with Bcl proteins either directly or indirectly; however, these data have not been systematically described. Some viruses encode proteins that reprogramme host cellular signalling pathways controlling cell differentiation, proliferation, genomic integrity, cell death, and immune system recognition. This review analyses and summarises the existing data and discusses how viral proteins interfere with normal pro- and anti-apoptotic functions of Bcl-2 and Bcl-xL. Particularly, this article focuses on how viral proteins, such as Herpesviruses, HTLV-1, HPV and HCV, block apoptosis and how accumulation of such interference predisposes cancer development. Finally, we discuss possible ways to prevent and treat cancers using a combination of traditional therapies and antiviral preparations that are effective against these viruses.

Role of infectious agents in the carcinogenesis of brain and head and neck cancers.

This review concentrates on tumours that are anatomically localised in head and neck regions. Brain cancers and head and neck cancers together account for more than 873,000 cases annually worldwide, with an increasing incidence each year. With poor survival rates at late stages, brain and head and neck cancers represent serious conditions. Carcinogenesis is a multi-step process and the role of infectious agents in this progression has not been fully identified. A major problem with such research is that the role of many infectious agents may be underestimated due to the lack of or inconsistency in experimental data obtained globally. In the case of brain cancer, no infection has been accepted as directly oncogenic, although a number of viruses and parasites are associated with the malignancy. Our analysis of the literature showed the presence of human cytomegalovirus (HCMV) in distinct types of brain tumour, namely glioblastoma multiforme (GBM) and medulloblastoma. In particular, there are reports of viral protein in up to 100% of GBM specimens. Several epidemiological studies reported associations of brain cancer and toxoplasmosis seropositivity. In head and neck cancers, there is a distinct correlation between Epstein-Barr virus (EBV) and nasopharyngeal carcinoma (NPC). Considering that almost every undifferentiated NPC is EBV-positive, virus titer levels can be measured to screen high-risk populations. In addition there is an apparent association between human papilloma virus (HPV) and head and neck squamous cell carcinoma (HNSCC); specifically, 26% of HNSCCs are positive for HPV. HPV type 16 was the most common type detected in HNSCCs (90%) and its dominance is even greater than that reported in cervical carcinoma. Although there are many studies showing an association of infectious agents with cancer, with various levels of involvement and either a direct or indirect causative effect, there is a scarcity of articles covering the role of infection in carcinogenesis of brain and head and neck cancers. We review recent studies on the infectious origin of these cancers and present our current understanding of carcinogenic mechanisms, thereby providing possible novel approaches to cancer treatment.

Role of viruses in the development of breast cancer.

The most common cancer worldwide among women is breast cancer. The initiation, promotion, and progression of this cancer result from both internal and external factors. The International Agency for Research on Cancer stated that 18-20% of cancers are linked to infection, and the list of definite, probable, and possible carcinogenic agents is growing each year. Among them, biological carcinogens play a significant role. In this review, data covering infection-associated breast and lung cancers are discussed and presented as possible involvements as pathogens in cancer. Because carcinogenesis is a multistep process with several contributing factors, we evaluated to what extent infection is significant, and concluded that members of the herpesvirus, polyomavirus, papillomavirus, and retrovirus families definitely associate with breast cancer. Detailed studies of viral mechanisms support this conclusion, but have presented problems with experimental settings. It is apparent that more effort needs to be devoted to assessing the role of these viruses in carcinogenesis, by characterizing additional confounding and synergistic effects of carcinogenic factors. We propose that preventing and treating infections may possibly stop or even eliminate certain types of cancers.

Childhood cancers: what is a possible role of infectious agents?

The etiology of childhood cancers has been studied for more than 40 years. However, most if not all cancers occurring in children are attributed to unknown causes. This review is focused on the role of infections in cancer development and progression in children. The main infectious agents include human herpesviruses, polyoma viruses, and human papilloma viruses. It is known that infections can lead to carcinogenesis through various mechanisms, and most likely act in addition to genetic and environmental factors. Given the importance of the infectious etiology of childhood cancers, clinical implications and possible prevention strategies are discussed.

The role of infectious agents in urogenital cancers.

Since the late 1990s, infectious agents have been thought to play a role in the pathogenesis of approximately 15% of cancers. It is now widely accepted that infection of stomach tissue with the bacteria Helicobacter pylori is an important cause of stomach adenocarcinoma. In addition, oncogenic viruses, such as papilloma viruses, herpes viruses, and hepadnaviruses are strongly associated with increased risk of cervical cancer, lymphomas, liver cancer, amongst others. However, in the scientific community the percentage of cancers caused by pathogens is believed to be far higher than 15%. A significant volume of data collected to date show an association between infectious agents and urogenital cancers. These agents include Chlamydia trachomatis, Neisseria gonorrhoea, Mycoplasma genitalium and certain viruses that have been implicated in ovarian cancer. Other pathogens include the hepatitis C and Epstein-Barr viruses, which are potentially involved in kidney cancer. In addition, infections with Schistosoma haematobium, the human papillomavirus, and human polyomaviruses are strongly associated with an increased risk of urinary bladder cancer. This article reviews publications available to date on the role of infectious agents in urogenital cancers. A greater understanding of the role of such agents could aid the identification of novel methods of urogenital cancer treatment.

Using antimicrobial adjuvant therapy in cancer treatment: a review.

Recent clinical and pre-clinical data demonstrate that adjuvant antimicrobial therapy is beneficial in cancer treatment. There could be several reasons for this effect, which include treating cancer associated bacteria and viruses, prophylaxis of post-chemotherapy infections due to immunosuppression, and antiproliferative effect of certain antimicrobials. Targeting cancer associated viruses and bacteria with antimicrobial agents is currently used for gastric, cervical, hematopoietic, liver and brain cancer. However this treatment is effective only in combination with conventional therapies. Antimicrobials can also have a direct antiproliferative and cytotoxic effect, and can cause apoptosis. Moreover, some antimicrobials are known to be helpful in overcoming side effects of drugs commonly used in cancer treatment. Chemotherapy related bacteremia and neutropenia can be overcome by the appropriately timed use of antimicrobials. This review summarizes the data on the effects of antivirals and antibiotics on cancer treatment and describes their mechanisms.

Pathogen-driven gastrointestinal cancers: Time for a change in treatment paradigm?

The regulation of cancerous tumor development is converged upon by multiple pathways and factors. Besides environmental factors, gastrointestinal (GI) tract cancer can be caused by chronic inflammation, which is generally induced by bacteria, viruses, and parasites. The role of these inducers in cancer development, cell differentiation and transformation, cell cycle deregulation, and in the expression of tumor-associated genes cannot be ignored. Although Helicobacter pylori activates many oncogenic pathways, particularly those in gastric and colorectal cancers, the role of viruses in tumor development is also significant. Viruses possess significant oncogenic potential to interfere with normal cell cycle control and genome stability, stimulating the growth of deregulated cells. An increasing amount of recent data also implies the association of GI cancers with bacterial colonization and viruses. This review focuses on host-cell interactions that facilitate primary mechanisms of tumorigenesis and provides new insights into novel GI cancer treatments.

Beta-cyclodextrin derivatives that inhibit anthrax lethal toxin.

Recently, we demonstrated that simultaneous blocking of bacterial growth by antibiotics and inhibition of anthrax toxin action with antibodies against protective antigen were beneficial for the treatment of anthrax. The present study examined the hypothesis that blocking the pore formed by protective antigen can inhibit the action of anthrax toxin. The potential inhibitors were chosen by a structure-based design using beta-cyclodextrin as the starting molecule. Several beta-cyclodextrin derivatives were evaluated for their ability to protect RAW 264.7 cells from the action of anthrax lethal toxin. Per-substituted aminoalkyl derivatives displayed inhibitory activity and were protective against anthrax lethal toxin action at low micromolar concentrations. These results provide the basis for a structure-based drug discovery program, with the goal of identifying new drug candidates for anthrax treatment.

Anthrax toxin induces hemolysis: an indirect effect through polymorphonuclear cells.

Anthrax toxin can induce hemolysis in the presence of polymorphonuclear cells (PMNs), an activity primarily mediated by protective antigen, with synergic effects provided by lethal factor and edema factor. Lethal factor and edema factor, individually or in combination, are incapable of lysing red blood cells. The requirement for the presence of PMNs indicates that hemolysis associated with Bacillus anthracis infection is indirect rather than direct, as observed in many other bacterial infections.