The oncomodulatory role of human cytomegalovirus in colorectal cancer: implications for clinical trials

Human Cytomegalovirus Oncoprotection across Diverse Populations, Tumor Histologies, and Age Groups: The Relevance for Prospective Vaccinal Therapy

The oncogenicity of the human cytomegalovirus (CMV) is currently being widely debated. Most recently, mounting clinical evidence suggests an anti-cancer effect via CMV-induced T cell-mediated tumor destruction. However, the data were mostly obtained from single-center studies and in vitro experiments. Broad geographic coverage is required to offer a global perspective. Our study examined the correlation between country-specific CMV seroprevalence (across 73 countries) and the age-standardized incidence rate (of 34 invasive tumors). The populations studied were stratified according to decadal age periods as the immunologic effects of CMV seropositivity may depend upon age at initial infection. The International Agency for Research on Cancer of the World Health Organization (IARC WHO) database was used. The multivariate linear regression analysis revealed a worldwide inverse correlation between CMV seroprevalence and the incidences of 62.8% tumors. Notably, this inverse link persists for all cancers combined (Spearman's ρ = -0.732, p < 0.001; β = -0.482, p < 0.001, adjusted R2 = 0.737). An antithetical and significant correlation was also observed in particular age groups for the vast majority of tumors. Our results corroborate the conclusions of previous studies and indicate that this oncopreventive phenomenon holds true on a global scale. It applies to a wide spectrum of cancer histologies, additionally supporting the idea of a common underlying mechanism-CMV-stimulated T cell tumor targeting. Although these results further advance the notion of CMV-based therapies, in-depth investigation of host-virus interactions is still warranted.

Integrated chromosomal instability and tumor microbiome redefined prognosis-related subtypes of pancreatic cancer

BACKGROUND

Pancreatic cancer is a common malignancy with poor prognosis and limited treatment. Here we aimed to investigate the role of host chromosomal instability (CIN) and tumor microbiome in the prognosis of pancreatic cancer patients.

METHODS

One hundred formalin-fixed paraffin-embedded (FFPE) pancreatic cancer samples were collected. DNA extracted from FFPE samples were analyzed by low-coverage whole-genome sequencing (WGS) via a customized bioinformatics workflow named ultrasensitive chromosomal aneuploidy detector.

RESULTS

Samples are tested according to the procedure of ultrasensitive chromosomal aneuploidy detector (UCAD). We excluded 2 samples with failed quality control, 1 patient lost to follow-up and 6 dead in the perioperative period. The final 91 patients were admitted for the following analyses. Thirteen (14.3%) patients with higher CIN score had worse overall survival (OS) than those with lower CIN score. The top 20 microbes in pancreatic cancer samples included 15 species of bacteria and 5 species of viruses. Patients with high human herpesvirus (HHV)-7 and HHV-5 DNA reads exhibited worse OS. Furthermore, we classified 91 patients into 3 subtypes. Patients with higher CIN score (n =13) had the worst prognosis (median OS 6.9 mon); patients with lower CIN score but with HHV-7/5 DNA load (n = 24) had worse prognosis (median OS 10.6 mon); while patients with lower CIN score and HHV-7/5 DNA negative (n = 54) had the best prognosis (median OS 21.1 mon).

CONCLUSIONS

High CIN and HHV-7/5 DNA load were associated with worse survival of pancreatic cancer. The novel molecular subtypes of pancreatic cancer based on CIN and microbiome had prognostic value.

Colorectal cancer and gut viruses: a visualized analysis based on CiteSpace knowledge graph

Background

Gut microbiome is a complex community of microbes present in the human gut and plays an important role in the occurrence and progression of colorectal cancer (CRC). However, the relationship between virus and CRC has not been fully understood.

Objective

To explore the hot spots and research trends in the field of CRC and virus.

Methods

By using the bibliometric analysis tool CiteSpace and based on the articles of the Web of Science Core Collection (WoSCC) database, the country, institution, highly cited literature, keywords and so on were visually analyzed.

Results

A total of 356 research articles on CRC from 2001 to 2023 were thoroughly analyzed. The USA and China have made the largest contribution in the field of virus and CRC. The Helmholtz Association published the most papers. There were relatively few cooperations among institutions from different countries. The results of keyword cluster analysis proved that the literature on the relationship between human cytomegalovirus (CMV) and CRC was the most widely studied aspect in this field. "Gut microbiota," "inflammatory bowel disease," "hepatitis b virus," and "human papillomavirus infection" are the current research hotspots; "oncolytic virus," "apoptosis," and "gut microbiome" are the recent research frontiers and should be paid closer attention.

Conclusion

By using CiteSpace bibliometric software, the visual analysis reflected the research trends and hot topics of virus and CRC. In addition, the prevalence and mechanism of specific virus on CRC were also reviewed, which provides valuable references for future CRC research.

Immune Microenvironment and Immunotherapeutic Management in Virus-Associated Digestive System Tumors

The development of cancer is a multifactorial phenomenon, while it constitutes a major global health problem. Viruses are an important factor that is involved in tumorigenesis and is associated with 12.1% of all cancer cases. Major examples of oncogenic viruses which are closely associated with the digestive system are HBV, HCV, EBV, HPV, JCV, and CMV. EBV, HPV, JCV, and CMV directly cause oncogenesis by expressing oncogenic proteins that are encoded in their genome. In contrast, HBV and HCV are correlated indirectly with carcinogenesis by causing chronic inflammation in the infected organs. In addition, the tumor microenvironment contains various immune cells, endothelial cells, and fibroblasts, as well as several growth factors, cytokines, and other tumor-secreted molecules that play a key role in tumor growth, progression, and migration, while they are closely interrelated with the virus. The presence of T-regulatory and B-regulatory cells in the tumor microenvironment plays an important role in the anti-tumor immune reaction. The tumor immune microenvironments differ in each type of cancer and depend on viral infection. The alterations in the immune microenvironment caused by viruses are also reflected in the effectiveness of immunotherapy. The present review aims at shedding light on the association between viruses and digestive system malignancies, the characteristics of the tumor immune microenvironment that develop, and the possible treatments that can be administered.

Mechanisms of Survival of Cytomegalovirus-Infected Tumor Cells

Human cytomegalovirus (HCMV) DNA and proteins are often detected in malignant tumors, warranting studies of the role that HCMV plays in carcinogenesis and tumor progression. HCMV proteins were shown to regulate the key processes involved in tumorigenesis. While HCMV as an oncogenic factor just came into focus, its ability to promote tumor progression is generally recognized. The review discusses the viral factors and cell molecular pathways that affect the resistance of cancer cells to therapy. CMV inhibits apoptosis of tumor cells, that not only promotes tumor progression, but also reduces the sensitivity of cells to antitumor therapy. Autophagy was found to facilitate either cell survival or cell death in different tumor cells. In leukemia cells, HCMV induces a "protective" autophagy that suppresses apoptosis. Viral factors that mediate drug resistance and their interactions with key cell death pathways are necessary to further investigate in order to develop agents that can restore the tumor sensitivity to anticancer drugs.

Viruses in colorectal cancer

Increasing evidence suggests that microorganisms might represent at least highly interesting cofactors in colorectal cancer (CRC) oncogenesis and progression. Still, associated mechanisms, specifically in colonocytes and their microenvironmental interactions, are still poorly understood. Although, currently, at least seven viruses are being recognized as human carcinogens, only three of these – Epstein–Barr virus (EBV), human papillomavirus (HPV) and John Cunningham virus (JCV) – have been described, with varying levels of evidence, in CRC. In addition, cytomegalovirus (CMV) has been associated with CRC in some publications, albeit not being a fully acknowledged oncovirus. Moreover, recent microbiome studies set increasing grounds for new hypotheses on bacteriophages as interesting additional modulators in CRC carcinogenesis and progression. The present Review summarizes how particular groups of viruses, including bacteriophages, affect cells and the cellular and microbial microenvironment, thereby putatively contributing to foster CRC. This could be achieved, for example, by promoting several processes – such as DNA damage, chromosomal instability, or molecular aspects of cell proliferation, CRC progression and metastasis – not necessarily by direct infection of epithelial cells only, but also by interaction with the microenvironment of infected cells. In this context, there are striking common features of EBV, CMV, HPV and JCV that are able to promote oncogenesis, in terms of establishing latent infections and affecting p53‐/pRb‐driven, epithelial–mesenchymal transition (EMT)‐/EGFR‐associated and especially Wnt/β‐catenin‐driven pathways. We speculate that, at least in part, such viral impacts on particular pathways might be reflected in lasting (e.g. mutational or further genomic) fingerprints of viruses in cells. Also, the complex interplay between several species within the intestinal microbiome, involving a direct or indirect impact on colorectal and microenvironmental cells but also between, for example, phages and bacterial and viral pathogens, and further novel species certainly might, in part, explain ongoing difficulties to establish unequivocal monocausal links between specific viral infections and CRC.

Berberine in Human Oncogenic Herpesvirus Infections and Their Linked Cancers

Human herpesviruses are known to induce a broad spectrum of diseases, ranging from common cold sores to cancer, and infections with some types of these viruses, known as human oncogenic herpesviruses (HOHVs), can cause cancer. Challenges with viral latency, recurrent infections, and drug resistance have generated the need for finding new drugs with the ability to overcome these barriers. Berberine (BBR), a naturally occurring alkaloid, is known for its multiple biological activities, including antiviral and anticancer effects. This paper comprehensively compiles all studies that have featured anti-HOHV properties of BBR along with promising preventive effects against the associated cancers. The mechanisms and pathways induced by BBR via targeting the herpesvirus life cycle and the pathogenesis of the linked malignancies are reviewed. Approaches to enhance the therapeutic efficacy of BBR and its use in clinical practice as an anti-herpesvirus drug are also discussed.

Chronic Pediatric Immune Thrombocytopenia Is Not Associated With Herpes Virus Infection Status

Background: Immune thrombocytopenia (ITP) is characterized by non-chronic (transient, <12 months) and chronic (≥12 months) decline in the number of platelets. Herpes virus infections have been shown, in many studies, to be associated with the development of ITP. However, it remains unclear whether the herpes virus infection status is associated with the chronic ITP. Methods: We reviewed 480 primary pediatric patients with ITP in the period from January 2017 to December 2019. The prevalence of herpes virus antibodies including the Cytomegalovirus (CMV), Herpes simplex virus 1 (HSV-1), Herpes simplex virus 2 (HSV-2), and Epstein Barr virus were recorded. The levels of serum complement C3 and C4, T (CD3+, CD4+, CD8+), B (CD19+) lymphocytes, and natural killer (CD16+ 56+) cells were also analyzed. Multivariate analysis was used to evaluate the associations between chronic ITP and herpes virus infection status. Results: Compared with non-chronic, patients with chronic ITP had older age (≥3 years), lower levels of hemoglobin and complement C3, and lower probability of CMV and HSV-2 infections (IgM positive; p < 0.05). Patients with herpes virus infection had lower serum platelet counts (p < 0.001), lower complement C3 levels and lower CD4+/CD8+ cells ratio (p < 0.05). Furthermore, platelet counts were positively correlated with CD4+/CD8+ cells ratios (r = 0.519; p = 0.0078), and negatively correlated with T cells (CD3+: r = -0.458, p = 0.0213; CD8+: r = -0.489, p = 0.0131). Multivariate analysis showed that age (OR, 1.644; 95%CI, 1.007-2.684; p = 0.047) was an adverse risk factor for chronic ITP and CMV IgM positive (OR, 0.241; 95%CI, 0.072-0.814; p = 0.022) had lower risk of chronic ITP development, while other herpes virus infection statuses and clinical features were not. Conclusion: Although herpes virus infections were associated with the onset of ITP, our findings indicated that herpes virus infection status might not be a risk factor for chronic ITP.

The role of viruses in adenocarcinoma development

Cancer is a leading public health issue that accounts for million deaths around the world every year. Human cancers contain over 100 types, which are categorized into different groups. Adenocarcinoma is one of those categories of cancer that begins from the glans and involves various tissues such as lung, esophagus, pancreas, prostate and colorectal. A range of risk factors has been identified for the development and progression of adenocarcinomas. One of these risk factors are viruses that serves special mechanisms to affect important host cell factors and tumorigenic pathways, contributing in development and promotion of adenocarcinomas. Here, we summarized the main viruses and their mechanisms implicated in the course of various adenocarcinomas development.

Cancer Patients Have a Higher Risk Regarding COVID-19 - and Vice Versa?

The world is currently suffering from a pandemic which has claimed the lives of over 230,000 people to date. The responsible virus is called severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and causes the coronavirus disease 2019 (COVID-19), which is mainly characterized by fever, cough and shortness of breath. In severe cases, the disease can lead to respiratory distress syndrome and septic shock, which are mostly fatal for the patient. The severity of disease progression was hypothesized to be related to an overshooting immune response and was correlated with age and comorbidities, including cancer. A lot of research has lately been focused on the pathogenesis and acute consequences of COVID-19. However, the possibility of long-term consequences caused by viral infections which has been shown for other viruses are not to be neglected. In this regard, this opinion discusses the interplay of SARS-CoV-2 infection and cancer with special focus on the inflammatory immune response and tissue damage caused by infection. We summarize the available literature on COVID-19 suggesting an increased risk for severe disease progression in cancer patients, and we discuss the possibility that SARS-CoV-2 could contribute to cancer development. We offer lines of thought to provide ideas for urgently needed studies on the potential long-term effects of SARS-CoV-2 infection.

Uncovering the Anticancer Potential of Murine Cytomegalovirus against Human Colon Cancer Cells

Human cytomegalovirus (HCMV) components are often found in tumors, but the precise relationship between HCMV and cancer remains a matter of debate. Pro-tumor functions of HCMV were described in several studies, but an association between HCMV seropositivity and reduced cancer risk was also evidenced, presumably relying on recognition and killing of cancer cells by HCMV-induced lymphocytes. This study aimed at deciphering whether CMV influences cancer development in an immune-independent manner. Using immunodeficient mice, we showed that systemic infection with murine CMV (MCMV) inhibited the growth of murine carcinomas. Surprisingly, MCMV, but not HCMV, also reduced human colon carcinoma development in vivo. In vitro, both viruses infected human cancer cells. Expression of human interferon-β (IFN-β) and nuclear domain (ND10) were induced in MCMV-infected, but not in HCMV-infected human colon cancer cells. These results suggest a decreased capacity of MCMV to counteract intrinsic defenses in the human cellular host. Finally, immunodeficient mice receiving peri-tumoral MCMV therapy showed a reduction of human colon cancer cell growth, albeit no clinical sign of systemic virus dissemination was evidenced. Our study, which describes a selective advantage of MCMV over HCMV to control human colon cancer, could pave the way for the development of CMV-based therapies against cancer.

The prevalence of EBV and CMV DNA in epithelial ovarian cancer

Background

The underlying cause of epithelial ovarian cancer (EOC) is unknown. It has been theorized that infectious agents could contribute to ovarian tumorigenesis.

Objective

To investigate the potential role of oncogenic viral infection in EOC, we examined the prevalence of Epstein-Barr Virus (EBV) DNA and cytomegalovirus (CMV) DNA in EOC tissue samples.

Methods

Formalin-fixed, paraffin-imbedded (FFPE) tumor tissue samples from 198 patients included in the Danish Pelvic Mass Study were studied: 163 with serous adenocarcinomas, 15 with endometrioid adenocarcinomas, 11 with mucinous adenocarcinomas, and nine with clear-cell carcinomas. For controls in the EBV analysis, we used 176 tissue samples from patients diagnosed with benign mucinous cystadenomas. EBV and CMV genotyping was performed by real-time polymerase chain reaction with CMV and EBV CE-IVD approved kits. In-situ hybridization (ISH) was performed on the EBV positive samples.

Results

Sufficient DNA material was obtained in 191 and 174 tissue samples from cases and controls, respectively. Ten of 191 case samples (5.2%) and one of 174 control samples (0.5%) were positive for EBV DNA (P value = 0.011). CMV DNA was detected in only one case sample (0.5%). ISH confirmed that three of the samples were of stromal origin, while the remaining seven tested negative for EBV.

Conclusions

This study is the first to demonstrate a higher prevalence of EBV DNA in tissue samples from patients with EOC than in a benign control group. However, the cellular origin of seven of the samples could not be determined by ISH analysis. Our study did not support an association between CMV and EOC.

A tumor-specific endogenous repetitive element is induced by herpesviruses

Tandem satellite repeats account for 3% of the human genome. One of them, Human Satellite II (HSATII), is highly expressed in several epithelial cancers and cancer cell lines. Here we report an acute induction of HSATII RNA in human cells infected with two herpes viruses. We show that human cytomegalovirus (HCMV) IE1 and IE2 proteins cooperate to induce HSATII RNA affecting several aspects of the HCMV replication cycle, viral titers and infected-cell processes. HSATII RNA expression in tissue from two chronic HCMV colitis patients correlates with the strength of CMV antigen staining. Thus, endogenous HSATII RNA synthesis after herpesvirus infections appears to have functionally important consequences for viral replication and may provide a novel insight into viral pathogenesis. The HSATII induction seen in both infected and cancer cells suggests possible convergence upon common HSATII-based regulatory mechanisms in these seemingly disparate diseases.

Th17 cytokine profiling of colorectal cancer patients with or without enterovirus 71 antigen expression

OBJECT

Th17 cytokines have been identified in several types of human cancers. In this pilot study, the expression of Th17 cytokines profiling in enteroviruses 71 (EV71) associated colorectal cancer (CRC) were explored.

METHODS

66 patients with CRC were enrolled in this study; immune- histochemical analyses were performed on cancerous tissues and adjacent non- cancerous tissues of the patients. Serum Th17 cytokines of CRC patients and healthy controls were measured using a Luminex 200 analyzer.

RESULTS

Cancerous tissues had more positive EV71 antigen expression than adjacent non- cancerous tissues. In TNM II-III CRC, 59.9% of cancerous tissues were observed to be EV71 positive; on the contrary, 65.2% of the adjacent non- cancerous epithelium was EV71 negative. In TNM I CRC, all adjacent non- cancerous epithelium was virus negative, but in TNM IV, half of adjacent non- cancerous tissues were virus positive. Serum IL-10 were significantly higher in CRC patients than in healthy controls, and IL-10 concentrations in the EV71 positive group were higher than those of the EV71 negative group, with the highest IL-10 levels being observed in CRC patients with strong positive group (P < 0.05). Similar results were found for IL-21 and IL-23. IL-17 levels were higher in CRC patients than in healthy controls, there was no significant difference in IL-17 between the viral positive and viral negative groups (P > 0.05).

CONCLUSION

Persistent existing EV71 viral antigens in intestinal tissues are positively associated with TNM III/IV CRC. EV71 latent infection recruits Th17 cells in the colorectal tumor site, stimulating Th17 cytokine production that closely associated with CRC carcinogenesis.

Role of viruses in gastrointestinal cancer

Gastrointestinal cancers are a global public health problem, which represent a vast majority of all cancer-caused deaths in both men and women. On the other hand, viral pathogens have been long implicated as etiological factors in the onset of certain human cancers, including gastrointestinal tumors. In this regard, Human Papilloma Virus (HPV), Epstein-Barr Virus (EBV), and John Cunningham Virus (JCV) have been more strongly suggested to be involved in gastrointestinal carcinogenesis; so that, the association of HPV with oropharyngeal and anal cancers and also the association of EBV with gastric cancer have been etiologically confirmed by epidemiological and experimental investigations. Although, the association of other viruses is less evident, but may rely on co-factors for their oncogenic roles. Therefore, to improve the prevention and treatment of these classes of cancer, their association with viral agents as potential risk factors should be investigated with care. In this respect, the present review has focused on the existing literature on the subject of viral involvement in gastrointestinal tumorgenesis, by covering and discussing various gastrointestinal cancers, corresponding viral agents and their oncogenic aspects and then summarizing evidences either supporting or rejecting a causal role of these pathogens in gastrointestinal malignancies.

Rare Human Codons and HCMV Translational Regulation

Restriction of protein synthesis characterizes human cytomegalovirus (HCMV) latency in the human host. In analyzing the molecular factors that hinder HCMV expression, the present study shows that HCMV genes frequently use 6 rare codons, i.e., GCG (Ala), CCG (Pro), CGT (Arg), CGC (Arg), TCG (Ser), and ACG (Thr). In some instances, the rare host codons are clustered along viral nucleotide sequences and represent the majority in sequences encoding short alanine and proline repeats. Given the positive correlation between codon usage, tRNA content, and protein production, the results support the hypothesis that HCMV usage of rare human codons might hinder HCMV protein synthesis, in this way leading to HCMV latency.

Regulation of Wnt/β-catenin signaling by herpesviruses

The Wnt/β-catenin signaling pathway is instrumental in successful differentiation and proliferation of mammalian cells. It is therefore not surprising that the herpesvirus family has developed mechanisms to interact with and manipulate this pathway. Successful coexistence with the host requires that herpesviruses establish a lifelong infection that includes periods of latency and reactivation or persistence. Many herpesviruses establish latency in progenitor cells and viral reactivation is linked to host-cell proliferation and differentiation status. Importantly, Wnt/β-catenin is tightly connected to stem/progenitor cell maintenance and differentiation. Numerous studies have linked Wnt/β-catenin signaling to a variety of cancers, emphasizing the importance of Wnt/β-catenin pathways in development, tissue homeostasis and disease. This review details how the alpha-, beta-, and gammaherpesviruses interact and manipulate the Wnt/β-catenin pathway to promote a virus-centric agenda.

Human Cytomegalovirus DNA Quantification and Gene Expression in Gliomas of Different Grades

Gliomas are the most common type of primary brain tumors. The most aggressive type, Glioblastoma multiforme (GBM), is one of the deadliest human diseases, with an average survival at diagnosis of about 1 year. Previous evidence suggests a link between human cytomegalovirus (HCMV) and gliomas. HCMV has been shown to be present in these tumors and several viral proteins can have oncogenic properties in glioma cells. Here we have investigated the presence of HCMV DNA, RNA and proteins in fifty-two gliomas of different grades of malignancy. The UL83 viral region, the early beta 2.7 RNA and viral protein were detected in 73%, 36% and 57% by qPCR, ISH and IHC, respectively. Positivity of the viral targets and viral load was independent of tumor type or grade suggesting no correlation between viral presence and tumor progression. Our results demonstrate high prevalence of the virus in gliomas from Brazilian patients, contributing to a better understanding of the association between HCMV infection and gliomas worldwide and supporting further investigations of the virus oncomodulatory properties.

Human cytomegalovirus-encoded US28 may act as a tumor promoter in colorectal cancer

AIM: To assess human cytomegalovirus-encoded US28 gene function in colorectal cancer (CRC) pathogenesis.

METHODS: Immunohistochemical analysis was performed to determine US28 expression in 103 CRC patient samples and 98 corresponding adjacent noncancerous samples. Patient data were compared by age, sex, tumor location, histological grade, Dukes’ stage, and overall mean survival time. In addition, the US28 gene was transiently transfected into the CRC LOVO cell line, and cell proliferation was assessed using a cell counting kit-8 assay. Cell cycle analysis by flow cytometry and a cell invasion transwell assay were also carried out.

RESULTS: US28 levels were clearly higher in CRC tissues (38.8%) than in adjacent noncancerous samples (7.1%) (P = 0.000). Interestingly, elevated US28 amounts in CRC tissues were significantly associated with histological grade, metastasis, Dukes’ stage, and overall survival (all P < 0.05); meanwhile, US28 expression was not significantly correlated with age, sex or tumor location. In addition, multivariate Cox regression data revealed US28 level as an independent CRC prognostic marker (P = 0.000). LOVO cells successfully transfected with the US28 gene exhibited higher viability, greater chemotherapy resistance, accelerated cell cycle progression, and increased invasion ability.

CONCLUSION: US28 expression is predictive of poor prognosis and may promote CRC.