Does JC virus have a role in the etiology and prognosis of Egyptian colorectal carcinoma?

Patient-individual cancer cell lines and tissue analysis delivers no evidence of sequences from DNA viruses in colorectal cancer cells

Background

Several DNA viruses are highly suspicious to have oncogenic effects in humans. This study investigates the presence of potentially oncogenic viruses such as SV40, JCV, BKV and EBV in patient-derived colorectal carcinoma (CRC) cells typifying all molecular subtypes of CRC.

Methods

Sample material (gDNA and cDNA) of a total of 49 patient-individual CRC cell lines and corresponding primary material from 11 patients, including normal, tumor-derived and metastasis-derived tissue were analyzed for sequences of SV40, JVC, BKV and EBV using endpoint PCR. In addition, the susceptibility of CRC cells to JCV and BKV was examined using a long-term cultivation approach of patient-individual cells in the presence of viruses.

Results

No virus-specific sequences could be detected in all specimens. Likewise, no morphological changes were observed and no evidence for viral infection or integration could be provided after long term CRC cell cultivation in presence of viral particles.

Conclusions

In summary, the presented data suggest that there is no direct correlation between tumorigenesis and viral load and consequently no evidence for a functional role of the DNA viruses included into this analysis in CRC development.

Prevalence of JC and BK viruses in Patients with Colorectal Cancer: A Systematic Review and Meta- Analysis

INTRODUCTION

Polyomaviruses including BK virus (BKV) and JC virus (JCV) are widespread in human and have been associated with colorectal cancer (CRC) in some studies. The aim of present systematic review and meta-analysis article is to calculate the pooled prevalence of BKV and JCV in patients with CRC and assessing their association with this malignancy.

MATERIALS AND METHODS

Domestic databases and Sciences Direct, PubMed, ProQuest, Web of Sciences and Scopus were searched for relevant articles up to 2nd  June 2019Two independent reviewers extracted the related data from eligible articles. The pooled prevalence and pooled odds ratio (POR) and their 95% confidence interval (95% CI) were calculated using "metaprop" and "metan" commands in Stata 14. Where I2 statistics were >50%, the random effect model was used.

RESULTS

From 1461 relevant studies, 24 articles were eligible and included in the qualitative while 19 articles included in quantitative analysis. The pooled prevalence based on diagnostic methods varies from 29% using immunohistochemistry to 52% using nested-PCR method. The likelihood of being infected with JCV  was significantly higher in CRC patients compared to healthy (POR: 4.41, 95% CI: 2.13 - 9.13) controls, normal adjacent mucosa (POR: 2.79, 95% CI: 1.3-5.9) and colorectal adenoma (POR: 3.1, 95% CI: 1.5-6.5) but was not significant when non-CRC patients used as control group.

CONCLUSION

The prevalence of JCV in colorectal patients was substantially variable by different methods and targets. The significant association between JCV and CRC that was observed in the present study is not indicative of causation and should be studied more in large-scale prospective designs.

Multiple Signatures of the JC Polyomavirus in Paired Normal and Altered Colorectal Mucosa Indicate a Link with Human Colorectal Cancer, but Not with Cancer Progression

The JC polyomavirus (JCV) has been repeatedly but discordantly detected in healthy colonic mucosa, adenomatous polyps, and colorectal cancer (CRC), and proposed to contribute to oncogenesis. The controversies may derive from differences in JCV targets, patient’s cohorts, and methods. Studies of simultaneous detection, quantification, and characterization of JCV presence/expression in paired samples of normal/altered tissues of the same patient are lacking. Therefore, we simultaneously quantified JCV presence (DNA) and expression (mRNA and protein) of T-antigen (T-Ag), Viral Protein 1 (Vp1), and miR-J1-5p in paired normal/altered tissues of CRC or polyps, and from controls. JCV signatures were found in most samples. They increased in patients, but were higher in normal mucosa than in corresponding polyp or CRC lesions. JCV non-coding control region (NCCR) DNA rearrangements increased in CRC patients, also in normal mucosa, thus before the onset of the lesion. A new ∆98bp NCCR DNA rearrangement was detected. T-Ag levels were higher in normal mucosa than in adenoma and adenocarcinoma lesions, but decreased to levels of controls in established CRC lesions. In CRC, miR-J1-5p expression decreased with CRC progression. Vp1 expression was not detected. The data indicate a JCV link with the disease, but possible JCV contributes to oncogenesis should occur at pre-polyp stages.

Association between JC virus and colorectal cancer: systematic review and meta-analysis

Objective: Given the probable role of JC virus in associate with increasing the odds of colorectal cancer, this study was conducted systematically to evaluate the association between JC virus and colorectal cancer.Materials and methods: Systematic reviews of the articles published prior to January 1, 2019 without time and place limitations were done independently through the PubMed, ISI, EMBASE and Medline main databases. The heterogeneity rate was assessed through I2, Chi2 and Tau2, and the sensitivity analysis and meta-regression were used to investigate the source of heterogeneity among the studies.Results: 24 studies with a sample size of 2576 were finally entered into the meta-analysis. The results showed that the prevalence of JC virus in colorectal cancer tissues was about 43% (95% CI: 29% -58%). The meta-analysis results also showed that the presence of JCV in colorectal tissues increased the odds of colorectal cancer 4.70 times as much (OR Pooled = 4.70; 95% CI: 2.95-7.50). Also, the results of the sub-group analysis indicated that the presence of JC virus, compared with the tissues adjacent to the tumour and the healthy control tissues, increased the odds of colorectal cancer (OR Pooled = 4.50, 95% CI: 2.09-9.65 and OR Pooled = 4.70, 95% CI: 2.95-7.50) respectively.Conclusion: The meta-analysis showed that as an oncogene virus, JC could increase the odds of colorectal cancer, reinforcing the hypothesis on the role of viral factors in the pathogenesis of cancers.

Presence of JC Polyomavirus in Nonneoplastic Inflamed Colon Mucosa and Primary and Metastatic Colorectal Cancer

Background

Despite decades of epidemiologic and histopathologic investigations, the association between JC polyomavirus (JCPyV) infection and colorectal cancer (CRC) remains controversial.

Objective

This study tested the presence of JCPyV sequences and determined the viral load in a series of colorectal samples from Iranian patients. In total, 223 formalin-fixed paraffin-embedded samples from patients diagnosed with primary and metastatic CRC as well as with nonneoplastic inflamed colon mucosa were analyzed by quantitative real-time PCR for the presence of JCPyV large tumor antigen (LT-Ag) sequences.

Results

JCPyV LT-Ag sequences were detected in 18.6% of the CRC tissues and in 15.5% of the nonneoplastic control group. Viral LT-Ag was quantified in 18/100 primary colon adenocarcinomas, 2/10 metastatic adenocarcinomas, and 1/3 primary adenocarcinomas of the rectum. Two JCPyV-positive metastatic tumors presented a negative test result for JCPyV in the corresponding primary tumor. The median JCPyV LT-Ag copy number was 64 × 10^-2 per cell and 14 × 10^-2 per cell in the CRC cases and the nonneoplastic samples, respectively. There was no statistically significant difference between the two study groups regarding median LT-Ag DNA load (p = 0.059). Among the JCPyV-positive samples, the LT-Ag DNA load was higher in 2 metastatic tumors (from a patient with lung metastasis: 232 × 10^-2 copies per cell; from a patient with liver metastasis: 121 × 10^-2 copies per cell).

Conclusions

The detection of JCPyV DNA at low copy numbers (lower than 1 viral copy per cell equivalent) and the absence of viral sequences in the corresponding primary tumors of the JCPyV-positive metastatic samples weaken the hypothesis of an etiological role of JCPyV in primary CRC induction.

Human polyomaviruses and cancer: an overview

The name of the family Polyomaviridae, derives from the early observation that cells infected with murine polyomavirus induced multiple (poly) tumors (omas) in immunocompromised mice. Subsequent studies showed that many members of this family exhibit the capacity of mediating cell transformation and tumorigenesis in different experimental models. The transformation process mediated by these viruses is driven by viral pleiotropic regulatory proteins called T (tumor) antigens. Similar to other viral oncoproteins T antigens target cellular regulatory factors to favor cell proliferation, immune evasion and downregulation of apoptosis. The first two human polyomaviruses were isolated over 45 years ago. However, recent advances in the DNA sequencing technologies led to the rapid identification of additional twelve new polyomaviruses in different human samples. Many of these viruses establish chronic infections and have been associated with conditions in immunosuppressed individuals, particularly in organ transplant recipients. This has been associated to viral reactivation due to the immunosuppressant therapy applied to these patients. Four polyomaviruses namely, Merkel cell polyomavirus (MCPyV), Trichodysplasia spinulosa polyomavirus (TSPyV), John Cunningham Polyomavirus (JCPyV) and BK polyomavirus (BKPyV) have been associated with the development of specific malignant tumors. However, present evidence only supports the role of MCPyV as a carcinogen to humans. In the present review we present a summarized discussion on the current knowledge concerning the role of MCPyV, TSPyV, JCPyV and BKPyV in human cancers.

A viral map of gastrointestinal cancers

Cancers of the gastrointestinal tract (GIT) are expected to account for approximately 20% of all cancers in 2017. Apart from their high incidence, GIT cancers show high mortality rates, placing these malignancies among the most prominent public health issues of our time. Cancers of the GIT are the result of a complex interplay between host genetic factors and environmental factors and frequently arise in the context of a continued active inflammatory response. Several tumor viruses are able to elicit such chronic inflammatory responses. In fact, several viruses have an impact on GIT tumor initiation and progression, as well as on patients' response to therapy and prognosis, through direct and indirect mechanisms. In this review, we have gathered information on different viruses' rates of infection, viral-driven specific carcinogenesis mechanisms and viral-related impact on the prognosis of cancers of the GIT (specifically in organs that have an interface with the environment - esophagus, stomach, intestines and anus). Overall, while some viral infections show a strong causal relation with specific gastrointestinal cancers, these represent a relatively small fraction of GIT malignancies. Other types of cancer, like Esophageal Squamous Cell Carcinoma, require further studies to confirm the carcinogenic role of some viral agents.

Review on the role of the human Polyomavirus JC in the development of tumors

Almost one fifth of human cancers worldwide are associated with infectious agents, either bacteria or viruses, and this makes the possible association between infections and tumors a relevant research issue. We focused our attention on the human Polyomavirus JC (JCPyV), that is a small, naked DNA virus, belonging to the Polyomaviridae family. It is the recognized etiological agent of the Progressive Multifocal Leukoencephalopathy (PML), a fatal demyelinating disease, occurring in immunosuppressed individuals.

JCPyV is able to induce cell transformation in vitro when infecting non-permissive cells, that do not support viral replication and JCPyV inoculation into small animal models and non human primates drives to tumor formation. The molecular mechanisms involved in JCPyV oncogenesis have been extensively studied: the main oncogenic viral protein is the large tumor antigen (T-Ag), that is able to bind, among other cellular factors, both Retinoblastoma protein (pRb) and p53 and to dysregulate the cell cycle, but also the early proteins small tumor antigen (t-Ag) and Agnoprotein appear to cooperate in the process of cell transformation.

Consequently, it is not surprising that JCPyV genomic sequences and protein expression have been detected in Central Nervous System (CNS) tumors and colon cancer and an association between this virus and several brain and non CNS-tumors has been proposed. However, the significances of these findings are under debate because there is still insufficient evidence of a casual association between JCPyV and solid cancer development.

In this paper we summarized and critically analyzed the published literature, in order to describe the current knowledge on the possible role of JCPyV in the development of human tumors.

Viral infections and colorectal cancer: a systematic review of epidemiological studies

Numerous studies have found the presence of viral DNA in colorectal tumor tissues. However, whether viral infections contribute to the risk of colorectal cancer (CRC) is still under debate. We aimed to provide an overview of published epidemiological studies on the association between viral infections and CRC. A systematic literature search was performed in PubMed to find relevant studies published until 8 May 2014. Information collected included study population, sample type, laboratory method and prevalence of viral infection in cancer or precancer patients and controls. We found 41 studies that fulfilled the selection criteria, all of which had cross-sectional or case-control designs, and most of which were of small to moderate size. Viral infections included human papillomaviruses (HPV), human polyomaviruses, human herpesviruses, human bocavirus and Inoue-Melnick virus. Inconsistent results were observed across studies. Many studies reported higher viral DNA prevalence in tumor tissues than in normal noncancerous tissues either in the same patients or in CRC-free controls. However, potential contamination or temporal sequence of the infection and cancer development were often unclear. Seroprevalence studies assessing antibody titers indicative of viral infections did not find statistically significant differences between CRC cases and healthy controls. Overall published evidence on the role of viral infections in CRC etiology remains limited. Given the potential importance of viral infections and their implication for prevention, there is a strong need for large, methodologically rigorous epidemiological studies.

Prospective study of seroreactivity to JC virus T-antigen and risk of colorectal cancers and adenomas

John Cunningham virus (JCV) is a common polyomavirus classified as a possible carcinogen by the International Agency for Research on Cancer. JCV may play a role in colorectal carcinogenesis, although we previously reported no association between JCV capsid antibodies and colorectal cancer. No studies have examined the role of seroreactivity to JCV T-antigen (T-Ag) oncoprotein in colorectal cancer. A case-control study nested within a community-based prospective cohort (CLUE II) was conducted. In 1989, 25,080 residents of Washington County, Maryland, were enrolled in CLUE II, completing baseline questionnaires and providing blood samples. At follow-up, 257 incident colorectal cancer cases were identified by linkage to population-based cancer registries through 2006 and matched to controls on age, sex, race, and date of blood draw. One hundred and twenty-three colorectal adenoma cases were identified through self-report during follow-up and matched to controls on age, sex, race, date of blood draw, and colorectal cancer screening. Baseline serum samples were tested for seroreactivity to JCV T-Ag. Associations between JCV T-Ag seroreactivity and colorectal cancer/adenomas were evaluated using conditional logistic regression models. Overall, seroreactivity to JCV T-Ag was not statistically significantly associated with the risk of either colorectal cancer [OR, 1.34; 95% confidence interval (CI), 0.89-2.01] or adenoma (OR, 1.30; 95% CI, 0.70-2.42), while a borderline association with colorectal cancer was observed among women (OR, 1.82; 95% CI, 1.00-3.31). Our past evaluation of JCV capsid seropositivity, combined with current findings, does not support a notable etiologic role for JCV infection in colorectal cancer.

JC virus in colorectal cancer: where do we stand?

AIm: Colorectal cancer (CRC) is a major cause of morbidity and mortality worldwide. In 2008, CRC was ranked as the second most common cancer among all newly diagnosed cancers in Jordan. It was recently suggested that the JC virus (JCV) could be linked to the development of CRC. However, this topic remains highly controversial. JCV is a common human polyomavirus that first infects individuals during early childhood. Infection with JCV can occur due to intake of contaminated water and food. The vast majority of those infected have no symptoms; however, severe immunosuppression can trigger reactivation of the virus. The oncogenicity of JCV was suggested to be related to its large T-antigen (T-Ag). This study aimed to investigate the incidence of JCV in CRC tissue of patients from northern Jordan. Materials & methods: Paraffin-embedded tissues from cases previously diagnosed with CRC were used. Immunohistochemistry and PCR techniques were used to detect the presence of JCV. Results: In total, 15.6% of CRC samples were positive for JCV T-Ag protein, whereas none of the noncancer control samples were positive. In total, 43.5% of CRC samples contained the JCV T-Ag gene compared with 16.7% within control samples. All CRC samples expressing the JCV T-Ag protein harbored the JCV T-Ag gene. However, not all samples that harbored the T-Ag gene expressed the T-Ag protein. Conclusion: Our results are consistent with recently published data and raise the possibility of an association between JCV infection and CRC. These findings deserve further investigation in larger-scale studies in order to elucidate the possible molecular carcinogenesis pathways in JCV-infected colorectal neoplasms.