Activation of c-Myc and Cyclin D1 by JCV T-Antigen and β-catenin in colon cancer

Wnt signaling in cancer: from biomarkers to targeted therapies and clinical translation

The Wnt signaling pathway plays a crucial role in development and tissue homeostasis, regulating key cellular processes such as proliferation, differentiation, and apoptosis. However, its abnormal activation is strongly associated with tumorigenesis, metastasis, and resistance to therapy, making it a vital target for cancer treatment. This review provides a comprehensive insight into the role of Wnt signaling in cancer, examining its normal physiological functions, dysregulation in malignancies, and therapeutic potential. We emphasize the importance of predicting Wnt signaling sensitivity and identify key biomarkers across various cancer types. Additionally, we address the challenges and future prospects of Wnt-targeted therapies, including biomarker discovery, advancements in emerging technologies, and their application in clinical practice.

Mohamed S, Gouda W. Case-control study: Unveiling human polyomaviruses and papillomavirus in Egyptian colorectal cancer patients

BACKGROUND

Colorectal cancer (CRC) is a cancer type that is thought to be influenced by human papillomaviruses (HPVs) and human polyomaviruses (HPyVs). In Egypt, CRC ranks as the 7th most common cancer, accounting for 3.47% of male cancers and 3% of female cancers. However, there is currently a lack of information regarding the presence of PyVs and HPVs co-infection specifically in CRC cases in Egypt. Therefore, the aim of this study was to investigate the occurrence of HPVs and HPyVs (JCPyV, BKPyV, and SV40) infections, as well as co-infections, among CRC patients in Egypt. Additionally, the study aimed to assess any potential association between these viral infections and tumor stages.

METHODS

In the present study, we analyzed a total of 51 tissue samples obtained from Egyptian CRC patients, along with 19 polyps' samples. Our investigation focused on the detection and genotyping of HPyVs using Real-Time PCR. Additionally, we employed real-time PCR for the detection of HPVs, and for their genotyping, we utilized a combination of PCR amplification followed by sequencing.

RESULTS

In our study, we found evidence of HPyVs infection in the CRC patients, specifically SV40 (25.5%) and BKPyV (19.6%). However, JCPyV was not detected in the samples that were examined. Additionally, we discovered that HPV was present in 43.1% of the CRC patients. When considering viral co-infections, 19.6% of the CRC samples showed coexistence of multiple viruses, while no co-infections were found in the polyps samples. Importantly, we observed a significant correlation between the presence of HPVs and advanced colorectal tumor grades B2 and D.

CONCLUSION

Our findings provide valuable data for the detection of oncogenic viruses in colorectal cancer (CRC) and underscore the association of viral co-infections with advanced tumor stages. However, further research with larger cohorts is necessary to validate these findings and strengthen their significance in the field of CRC.

Clinical Impact of C-myc Oncogenic Diversity on Solid and Lymphoid Malignancies

INTRODUCTION

Onset and progression of malignant tumors is a multistep process including a variety of gross chromosomal and specific genes' deregulation. Among oncogenes that are frequently altered in solid and also in hematological malignancies, the C-myc (gene locus: 8q24.21) plays a pivotal role. C-myc is a proto-oncogene encoding for a nuclear phosphoprotein implicated in cell cycle progression, apoptosis and cellular differentiation and transformation.

OBJECTIVE

The purpose of the current molecular review was to explore the differences of C-myc oncogenic activity in solid and lymphoid malignancies that modify its clinical impact on them.

MATERIAL AND METHOD

A systematic review of the literature in the international database PubMed was carried out. The year 2010 was set as a prominent time limit for the publication date of articles in the majority of them, whereas specific references of great importance and historical value in the field of C-myc gene discovery and analysis were also included. The following keywords were used: C-myc, oncogene, signaling pathway, malignancies, carcinoma, lymphoma. A pool of 43 important articles were selected for the present study at the basis of combining molecular knowledge with new targeted therapeutic strategies.

RESULTS

C-myc oncogene demonstrates two different mechanisms of deregulation: amplification, mutation and translocation patterns. These particular aspects of gene alteration are unique for solid and non-solid (hematological) malignancies, respectively.

CONCLUSIONS

C-myc is characterized by diversity regarding its deregulation mechanisms in malignancies derived from different tissues. C-myc translocation is sporadically combined with amplification ("complicon" formation) or mutations creating exotic genetic signatures. This "bi-phasic" C-myc deregulation model in the corresponding malignant tumor categories clinically affects the corresponding patients, also modifying the targeted therapeutic strategies on them.

RHAMM/hyaluronan inhibit β-catenin degradation, enhance downstream signaling, and facilitate fibrosarcoma cell growth

Increased hyaluronan deposition (HA) in various cancer tissues, including sarcomas, correlates with disease progression. The receptor for hyaluronic acid-mediated motility (RHAMM) expression is elevated in most human cancers. β-catenin is a critical downstream mediator of the Wnt signaling pathways, facilitating carcinogenic events characterized by deregulated cell proliferation. We previously showed that low molecular weight (LMW) HA/RHAMM/β-catenin signaling axis increases HT1080 fibrosarcoma cell growth. Here, focusing on mechanistic aspects and utilizing immunofluorescence and immunoprecipitation, we demonstrate that LMW HA treatment enhanced RHAMM intracellular localization (p ≤ 0.001) and RHAMM/β-catenin colocalization in HT1080 fibrosarcoma cells (p ≤ 0.05). Downregulating endogenous HA attenuated the association of RHAMM/β-catenin in HT1080 fibrosarcoma cells (p ≤ 0.0.01). Notably, Axin-2, the key β-catenin degradation complex component, and RHAMM were demonstrated to form a complex primarily to cell membranes, enhanced by LMW HA (p ≤ 0.01). In contrast, LMW HA attenuated the association of β-catenin and Axin-2 (p ≤ 0.05). The utilization of FH535, a Wnt signaling inhibitor, showed that LMW HA partially rescued the Wnt-dependent growth of HT1080 cells and restored the expression of Wnt/β-catenin mediators, cyclin-D1 and c-myc (p ≤ 0.05). B6FS fibrosarcoma cells with different HA metabolism do not respond to the LMW HA growth stimulus (p = NS). The present study identifies a novel LMW HA/RHAMM mechanism in a fibrosarcoma model. LMW HA regulates intracellular RHAMM expression, which acts as a scaffold protein binding β-catenin and Axin-2 at different cellular compartments to increase β-catenin expression, transcriptional activity, and fibrosarcoma growth.

The Effects of Deregulated Ribosomal Biogenesis in Cancer

Ribosomes are macromolecular ribonucleoprotein complexes assembled from RNA and proteins. Functional ribosomes arise from the nucleolus, require ribosomal RNA processing and the coordinated assembly of ribosomal proteins (RPs), and are frequently hyperactivated to support the requirement for protein synthesis during the self-biosynthetic and metabolic activities of cancer cells. Studies have provided relevant information on targeted anticancer molecules involved in ribosome biogenesis (RiBi), as increased RiBi is characteristic of many types of cancer. The association between unlimited cell proliferation and alterations in specific steps of RiBi has been highlighted as a possible critical driver of tumorigenesis and metastasis. Thus, alterations in numerous regulators and actors involved in RiBi, particularly in cancer, significantly affect the rate and quality of protein synthesis and, ultimately, the transcriptome to generate the associated proteome. Alterations in RiBi in cancer cells activate nucleolar stress response-related pathways that play important roles in cancer-targeted interventions and immunotherapies. In this review, we focus on the association between alterations in RiBi and cancer. Emphasis is placed on RiBi deregulation and its secondary consequences, including changes in protein synthesis, loss of RPs, adaptive transcription and translation, nucleolar stress regulation, metabolic changes, and the impaired ribosome biogenesis checkpoint.

Co-Detection of EBV and Human Polyomavirus JCPyV in a Case of AIDS-Related Multifocal Primary Central Nervous System Diffuse Large B-Cell Lymphoma

The human neurotropic Polyomavirus JCPyV is the widespread opportunistic causative pathogen of the fatal demyelinating disease progressive multifocal leukoencephalopathy; however, it has also been implicated in the oncogenesis of several types of cancers. It causes brain tumors when intracerebrally inoculated into rodents, and genomic sequences of different strains and expression of the viral protein large T-Antigen have been detected in a wide variety of glial brain tumors and CNS lymphomas. Here, we present a case of an AIDS-related multifocal primary CNS lymphoma in which JCPyV genomic sequences of the three regions of JCPyV and expression of T-Antigen were detected by PCR and immunohistochemistry, respectively. No capsid proteins were detected, ruling out active JCPyV replication. Sequencing of the control region revealed that Mad-4 was the strain of JCPyV present in tumor cells. In addition, expression of viral proteins LMP and EBNA-1 from another ubiquitous oncogenic virus, Epstein-Barr, was also detected in the same lymphocytic neoplastic cells, co-localizing with JCPyV T-Antigen, suggesting a potential collaboration between these two viruses in the process of malignant transformation of B-lymphocytes, which are the site of latency and reactivation for both viruses.

Loss of exosomal micro-RNA-200b-3p from hypoxia cancer-associated fibroblasts reduces sensitivity to 5-flourouracil in colorectal cancer through targeting high-mobility group box 3

Hypoxia-mediated tumor progression is a major problem in colorectal cancer (CRC). MicroRNA (miR)-200b-3p can attenuate tumorigenesis in CRC, while exosomal miRNAs derived from cancer-associated fibroblasts (CAFs) can promote cancer progression. Nevertheless, the function of exosomal miR-200b-3p derived from CAFs in CRC remains unclear. In this study, CAFs and normal fibroblasts (NFs) were isolated from CRC and adjacent normal tissues. Next, exosomes were isolated from the supernatants of CAFs cultured under normoxia and hypoxia. Cell viability was tested using the cell counting kit-8 assay, and flow cytometry was used to assess cell apoptosis. Cell invasion and migration were evaluated using the transwell assay. Dual-luciferase was used to investigate the relationship between miR-200b-3p and high-mobility group box 3 (HMBG3). Reverse transcription-quantitative polymerase chain reaction (RT-qPCR) was performed to determine the miR-200b-3p and HMBG3 level. Our results found that the miR-200b-3p level was sharply reduced in CRC tissues compared to adjacent normal tissues. Additionally, the miR-200b-3p level was reduced in exosomes derived from hypoxic CAFs compared to exosomes derived from CAFs under normoxia. Exosomes derived from hypoxic CAFs weakened the sensitivity of CRC cells to 5-fluorouracil (5-FU) compared to hypoxic CAFs-derived exosomes. However, hypoxic CAFs-derived exosomes with upregulated miR-200b-3p increased the sensitivity of CRC cells to 5-fluorouracil (5-FU) compared to hypoxic CAFs-derived exosomes. In addition, HMBG3 was identified as the downstream target of miR-200b-3p in CRC cells, and its overexpression partially reversed the anti-tumor effect of the miR-200b-3p agomir on CRC via the mediation of the β-catenin/c-Myc axis. Furthermore, compared to exosomes derived from normoxia CAFs, exosomes derived from hypoxic CAFs weakened the therapeutic effects of 5-FU on CRC in vivo via the upregulation of HMGB3 levels. Collectively, the loss of exosomal miR-200b-3p in hypoxia CAFs reduced the sensitivity to 5-FU in CRC by targeting HMGB3. Thus, our research outlines a novel method for the treatment of CRC.

The oncogenic roles of JC polyomavirus in cancer

JC polyomavirus (JCPyV) belongs to the human polyomavirus family. Based on alternative splicing, the early region encodes the large and small T antigens, while the late region encodes the capsid structural proteins (VP1, VP2, and VP3) and the agnoprotein. The regulatory transcription factors for JCPyV include Sp1, TCF-4, DDX1, YB-1, LCP-1, Purα, GF-1, and NF-1. JCPyV enters tonsillar tissue through the intake of raw sewage, inhalation of air droplets, or parent-to-child transmission. It persists quiescently in lymphoid and renal tissues during latency. Both TGF-β1 and TNF-α stimulates JCPyV multiplication, while interferon-γ suppresses the process. The distinct distribution of caspid receptors (α-2, 6-linked sialic acid, non-sialylated glycosaminoglycans, and serotonin) determines the infection capabilities of JCPyV virions, and JCPyV entry is mediated by clathrin-mediated endocytosis. In permissive cells, JCPyV undergoes lytic proliferation and causes progressive multifocal leukoencephalopathy, while its DNA is inserted into genomic DNA and leads to carcinogenesis in non-permissive cells. T antigen targets p53, β-catenin, IRS, Rb, TGF-β1, PI3K/Akt and AMPK signal pathways in cancer cells. Intracranial injection of T antigen into animals results in neural tumors, and transgenic mice develop neural tumors, lens tumor, breast cancer, gastric, Vater’s, colorectal and pancreatic cancers, insulinoma, and hepatocellular carcinoma. Additionally, JCPyV DNA and its encoded products can be detected in the brain tissues of PML patients and brain, oral, esophageal, gastric, colorectal, breast, cervical, pancreatic, and hepatocellular cancer tissues. Therefore, JCPyV might represent an etiological risk factor for carcinogenesis and should be evaluated for early prevention, diagnosis, and treatment of cancers.

The Oncogenic Effects, Pathways, and Target Molecules of JC Polyoma Virus T Antigen in Cancer Cells

JC polyoma virus (JCPyV) is a ubiquitous polyoma virus that infects the individual to cause progressive multifocal leukoencephalopathy and malignancies. Here, we found that T-antigen knockdown suppressed proliferation, glycolysis, mitochondrial respiration, migration, and invasion, and induced apoptosis and G₂ arrest. The reverse was true for T-antigen overexpression, with overexpression of Akt, survivin, retinoblastoma protein, β-catenin, β-transducin repeat-containing protein (TRCP), and inhibitor of growth (ING)1, and the underexpression of mammalian target of rapamycin (mTOR), phosphorylated (p)-mTOR, p-p38, Cyclin D1, p21, vascular endothelial growth factor (VEGF), ING2, and ING4 in hepatocellular and pancreatic cancer cells and tissues. In lens tumor cells, T antigen transcriptionally targeted viral carcinogenesis, microRNAs in cancer, focal adhesion, p53, VEGF, phosphoinositide 3 kinase-Akt, and Forkhead box O signaling pathways, fructose and mannose metabolism, ribosome biosynthesis, and choline and pyrimidine metabolism. At a metabolomics level, it targeted protein digestion and absorption, aminoacryl-tRNA biosynthesis, biosynthesis of amino acids, and the AMPK signal pathway. At a proteomic level, it targeted ribosome biogenesis in eukaryotes, citrate cycle, carbon metabolism, protein digestion and absorption, aminoacryl-tRNA biosynthesis, extracellular-matrix-receptor interaction, and biosynthesis of amino acids. In lens tumor cells, T antigen might interact with various keratins, ribosomal proteins, apolipoproteins, G proteins, ubiquitin-related proteins, RPL19, β-catenin, β-TRCP, p53, and CCAAT-enhancer-binding proteins in lens tumor cells. T antigen induced a more aggressive phenotype in mouse and human cancer cells due to oncogene activation, inactivation of tumor suppressors, and disruption of metabolism, cell adhesion, and long noncoding RNA-microRNA-target axes.

FOXQ1-mediated SIRT1 upregulation enhances stemness and radio-resistance of colorectal cancer cells and restores intestinal microbiota function by promoting β-catenin nuclear translocation

Background

Resistance of colorectal cancer (CRC) cells to radiotherapy considerably contributes to poor clinical outcomes of CRC patients. Microarray profiling in this study revealed the differentially expressed forkhead box Q1 (FOXQ1) in CRC, and thus we aimed to illustrate the role of FOXQ1 in CRC by modulating stemness and radio-resistance of CRC cells.

Methods

CRC and adjacent normal tissues were collected from CRC patients, and the correlation between FOXQ1 expression and CRC prognosis was analyzed. Subsequently, we determined the expression of FOXQ1, sirtuin 1 (SIRT1) and β-catenin in CRC tissues and cell lines. The binding affinity between FOXQ1 and SIRT1 and that between SIRT1 and β-catenin were validated with luciferase reporter gene, Co-IP and ChIP assays. Following a metagenomics analysis of CRC intestinal microbiota, the effects of the FOXQ1/SIRT1/β-catenin axis on CRC stem cell phenotypes and radio-resistance was evaluated in vitro and in vivo through manipulation of gene expression. Besides, mouse feces were collected to examine changes in intestinal microbiota.

Results

FOXQ1 was highly expressed in CRC tissues and cells and positively correlated with poor prognosis of CRC patients. FOXQ1 overexpression contributed to resistance of CRC cells to radiation. Knockdown of FOXQ1 inhibited the stemness of CRC cells and reversed their radio-resistance. FOXQ1 enhanced the transcriptional expression of SIRT1, and SIRT1 enhanced the expression and nuclear translocation of β-catenin. Knockdown of FOXQ1 repressed SIRT1 expression, thus reducing the stemness and radio-resistance of CRC cells. Moreover, FOXQ1 knockdown suppressed CRC xenograft formation in xenograft-bearing nude mice through inhibiting SIRT1 and β-catenin to reduce the content of pathological bacteria that were up-regulated in CRC.

Conclusion

FOXQ1-mediated SIRT1 upregulation augments expression and nuclear translocation of β-catenin and benefits CRC-related intestinal pathological bacterial, thereby enhancing the stemness and radio-resistance of CRC cells.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13046-021-02239-4.

Functional Domains of the Early Proteins and Experimental and Epidemiological Studies Suggest a Role for the Novel Human Polyomaviruses in Cancer

As their name indicates, polyomaviruses (PyVs) can induce tumors. Mouse PyV, hamster PyV and raccoon PyV have been shown to cause tumors in their natural host. During the last 30 years, 15 PyVs have been isolated from humans. From these, Merkel cell PyV is classified as a Group 2A carcinogenic pathogen (probably carcinogenic to humans), whereas BKPyV and JCPyV are class 2B (possibly carcinogenic to humans) by the International Agency for Research on Cancer. Although the other PyVs recently detected in humans (referred to here as novel HPyV; nHPyV) share many common features with PyVs, including the viral oncoproteins large tumor antigen and small tumor antigen, as their role in cancer is questioned. This review discusses whether the nHPyVs may play a role in cancer based on predicted and experimentally proven functions of their early proteins in oncogenic processes. The functional domains that mediate the oncogenic properties of early proteins of known PyVs, that can cause cancer in their natural host or animal models, have been well characterized and we examined whether these functional domains are conserved in the early proteins of the nHPyVs and presented experimental evidence that these conserved domains are functional. Furthermore, we reviewed the literature describing the detection of nHPyV in human tumors.

Pre-Administration of Berberine Exerts Chemopreventive Effects in AOM/DSS-Induced Colitis-Associated Carcinogenesis Mice via Modulating Inflammation and Intestinal Microbiota

Inflammatory activation and intestinal flora imbalance play an essential role in the development and progression of colorectal cancer (CRC). Berberine (BBR) has attracted great attention in recent years due to its heath-related benefits in inflammatory disorders and tumors, but the intricate mechanisms have not been fully elucidated. In this study, the effects and the mechanism of BBR on colon cancer were investigated in an azoxymethane (AOM)/dextran sodium sulfate (DSS)-induced colitis-associated carcinogenesis mice model. Our results showed that pre-administration of BBR showed a decrease in weight loss, disease activity index (DAI) score, and the number of colon tumors in mice, compared with the model group. The evidence from pathological examination indicated that the malignancy of intestinal tumors was ameliorated after pre-administration of BBR. Additionally, pre-administration with BBR suppressed the expression of pro-inflammatory factors (interleukin (IL)-6, IL-1β, cyclooxygenase (COX)-2 and tumor necrosis factor (TNF)-α) and the cell-proliferation marker Ki67, while expression of the tight junction proteins (ZO-1 and occludin) were increased in colon tissue. Moreover, the levels of critical pathway proteins involved in the inflammatory process (p-STAT3 and p-JNK) and cell cycle regulation molecules (β-catenin, c-Myc and CylinD1) exhibited lower expression levels. Besides, 16S rRNA sequence analysis indicated that pre-administration of BBR increased the ratio of Firmicutes/Bacteroidetes (F:M) and the relative abundance of potentially beneficial bacteria, while the abundance of cancer-related bacteria was decreased. Gavage with Lactobacillus rhamnosus can improve the anti-tumor effect of BBR. Overall, pre-administration of BBR exerts preventive effects in colon carcinogenesis, and the mechanisms underlying these effects are correlated with the inhibition of inflammation and tumor proliferation and the maintenance of intestinal homeostasis.

Anti-tumor activity of a recombinant soluble Fzd7 decoy receptor in human gastric and colon cancer cells

Objectives

Frizzled-7, the most common receptor of the Wnt signaling pathway, was significantly over-expressed in gastric (GC) and colorectal (CRC) cancers and stimulated tumorigenesis. The extracellular domain of Fzd7 (sFzd7) as a decoy receptor, could competitively bound with ligands and antagonize the interaction between Fzd7 receptors and Wnt ligands.

Materials and Methods

We expressed and purified the extracellular region of Fzd7 including cysteine-rich domain (33 aa-185 aa) from Escherichia coli by chromatography. The effect of sFzd7 was evaluated on AGS gastric and SW480 colon cancer cell lines expressing high levels of Fzd7 receptor. Accordingly, cell viability and apoptosis were measured using MTT and flow cytometry assays, respectively. Real-Time PCR determined the relative expression of the β-catenin and cyclin-D1 genes.

Results

After three days of treatment with sFzd7, the viability of AGS and SW480 cell lines was decreased in a dose-dependent manner. In addition, sFzd7 at concentrations of 10 and 20 ug/ml increased the rate of apoptosis. Especially at the concentration of 20 ug/ml, the apoptosis rate was remarkably high in AGS (P-value= 0.003) and SW480 cells (P-value= 0.0007). Finally, the expressions of β-catenin (P-value= 0.01) and cyclin-D1 (P-value= 0.02) were obviously decreased in SW480 cells. The same results were obtained in AGS cells, although not statistically significant.

Conclusion

sFzd7 decoy receptor inhibits tumor cell progression by attenuating the Wnt pathway through inhibiting Fzd7 receptors and Wnt ligand interaction. Hence, sFzd7 can be proposed as a candidate therapy for GC and CRC cells with high levels of Fzd7 expression.

Human polyomaviruses genomes in clinical specimens of colon cancer patients

Colon cancer is the third cause of cancer death in the developed countries. Some environmental factors are involved in its pathogenesis, including viral infections. The possible involvement of human polyomaviruses (HPyVs) in colon cancer pathogenesis has been previously reported, leading to inconsistent conclusions. Clinical specimens were collected from 125 colon cancer patients. Specifically, 110 tumor tissues, 55 negative surgical margins, and 39 peripheral blood samples were analyzed for the presence of six HPyVs: JC polyomavirus (JCPyV), BK polyomavirus (BKPyV), Merkel cell PyV (MCPyV), HPyV -6, -7, and -9 by means of DNA isolation and subsequent duplex Real Time quantitative polymerase chain reaction. HPyVs genome was detected in 33/204 samples (16.2%): the significant higher positivity was found in tumor tissues (26/110, 23.6%), followed by negative surgical margins (3/55, 5.5%, p < .05), and peripheral blood mononuclear cells (PBMCs) (4/39; 10.3%). HPyVs load was statistically higher only in the tumor tissues compared to negative surgical margins (p < .05). Specifically, MCPyV was detected in 19.1% (21/110) of tumor tissues, 3.6% (2/55) of negative surgical margins (p < .05), and 7.7% (3/39) of PBMCs; HPyV-6 in 2.7% (3/110) of tumor tissues, and 1.8% (1/55) of negative surgical margins; one tumor tissue (1/110, 0.9%) and one PBMCs sample (1/39, 2.6%) were positive for BKPyV; JCPyV was present in 0.9% (1/110) of tumor tissues. HPyV-7 and 9 were not detected in any sample. High prevalence and load of MCPyV genome in the tumor tissues might be indicative of a relevant rather than bystander role of the virus in the colon tumorigenesis.

Induction of Brain Tumors by the Archetype Strain of Human Neurotropic JCPyV in a Transgenic Mouse Model

JC Virus (JCPyV), a member of the Polyomaviridiæ family, is a human neurotropic virus with world-wide distribution. JCPyV is the established opportunistic infectious agent of progressive multifocal leukoencephalopathy, a fatal demyelinating disease, which results from the cytolytic infection of oligodendrocytes. Mutations in the regulatory region of JCPyV determine the different viral strains. Mad-1 the strain associated with PML contains two 98 base pair repeats, whereas the archetype strain (CY), which is the transmissible form of JCPyV, contains only one 98 tandem with two insertions of 62 and 23 base pairs respectively. The oncogenicity of JCPyV has been suspected since direct inoculation into the brain of rodents and primates resulted in the development of brain tumors and has been attributed to the viral protein, T-Antigen. To further understand the oncogenicity of JCPyV, a transgenic mouse colony containing the early region of the archetype strain (CY), under the regulation of its own promoter was generated. These transgenic animals developed tumors of neural crest origin, including: primitive neuroectodermal tumors, medulloblastomas, adrenal neuroblastomas, pituitary tumors, malignant peripheral nerve sheath tumors, and glioblastomas. Neoplastic cells from all different phenotypes express T-Antigen. The close parallels between the tumors developed by these transgenic animals and human CNS tumors make this animal model an excellent tool for the study of viral oncogenesis.

The Viral Janus: Viruses as Aetiological Agents and Treatment Options in Colorectal Cancer

In recent years, our understanding of the importance of microorganisms on and within our bodies has been revolutionized by the ability to characterize entire microbial communities. No more so is this true than in cases of disease. Community studies have revealed strong associations between microbial populations and disease states where such concomitance was previously absent from aetiology: including in cancers. The study of viruses, in particular, has benefited from the development of new community profiling techniques and we are now realising that their prominence within our physiology is nearly as broad as the diversity of the organisms themselves. Here, we examine the relationship between viruses and colorectal cancer (CRC), the leading cause of gastrointestinal cancer-related death worldwide. In CRC, viruses have been suggested to be involved in oncogenesis both directly, through infection of our cells, and indirectly, through modulating the composition of bacterial communities. Interestingly though, these characteristics have also led to their examination from another perspective—as options for treatment. Advances in our understanding of molecular and viral biology have caused many to look at viruses as potential modular biotherapeutics, where deleterious characteristics can be tamed and desirable characteristics exploited. In this article, we will explore both of these perspectives, covering how viral infections and involvement in microbiome dynamics may contribute to CRC, and examine ways in which viruses themselves could be harnessed to treat the very condition their contemporaries may have had a hand in creating.

Viruses in Cancers of the Digestive System: Active Contributors or Idle Bystanders?

The human virome, which is a collection of all the viruses that are present in the human body, is increasingly being recognized as an essential part of the human microbiota. The human gastrointestinal tract and related organs (e.g., liver, pancreas, and gallbladder)-composing the gastrointestinal (or digestive) system-contain a huge number of viral particles which contribute to maintaining tissue homeostasis and keeping our body healthy. However, perturbations of the virome steady-state may, both directly and indirectly, ignite/sustain oncogenic mechanisms contributing to the initiation of a dysplastic process and/or cancer progression. In this review, we summarize and discuss the available evidence on the association and role of viruses in the development of cancers of the digestive system.

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.

BK polyomavirus infection promotes growth and aggressiveness in bladder cancer

Background

Recent studies have confirmed the integration of the BK polyomavirus (BKPyV) gene into the cellular genome of urothelial carcinomas in transplant recipients, further confirming the correlation between BKPyV and urothelial carcinomas after transplantation. However, the role BKPyV infections play in the biological function of bladder cancer remains unclear.

Methods

We developed a BKPyV-infected bladder cancer cell model and a mice tumor model to discuss the role of BKPyV infections.

Results

Our research proves that BKPyV infections promote the proliferation, invasion and migration of bladder cancer cells, while the activation of β-catenin signaling pathway is one of its mediation mechanisms.

Conclusions

We first described BKPyV infection promotes the proliferation, invasion and migration of bladder cancer. We verified the role of β-catenin signaling pathway and Epithelial-Mesenchymal Transition effect in BKPyV-infected bladder cancer. These results provide meaningful information towards the diagnosis and treatment of clinical bladder cancer.

The Role of the JC Virus in Central Nervous System Tumorigenesis

Cancer is the second leading cause of mortality worldwide. The study of DNA tumor-inducing viruses and their oncoproteins as a causative agent in cancer initiation and tumor progression has greatly enhanced our understanding of cancer cell biology. The initiation of oncogenesis is a complex process. Specific gene mutations cause functional changes in the cell that ultimately result in the inability to regulate cell differentiation and proliferation effectively. The human neurotropic Polyomavirus JC (JCV) belongs to the family Polyomaviridae and it is the causative agent of progressive multifocal leukoencephalopathy (PML), which is a fatal neurodegenerative disease in an immunosuppressed state. Sero-epidemiological studies have indicated JCV infection is prevalent in the population (85%) and that initial infection usually occurs during childhood. The JC virus has small circular, double-stranded DNA that includes coding sequences for viral early and late proteins. Persistence of the virus in the brain and other tissues, as well as its potential to transform cells, has made it a subject of study for its role in brain tumor development. Earlier observation of malignant astrocytes and oligodendrocytes in PML, as well as glioblastoma formation in non-human primates inoculated with JCV, led to the hypothesis that JCV plays a role in central nervous system (CNS) tumorigenesis. Some studies have reported the presence of both JC viral DNA and its proteins in several primary brain tumor specimens. The discovery of new Polyomaviruses such as the Merkel cell Polyomavirus, which is associated with Merkel cell carcinomas in humans, ignited our interest in the role of the JC virus in CNS tumors. The current evidence known about JCV and its effects, which are sufficient to produce tumors in animal models, suggest it can be a causative factor in central nervous system tumorigenesis. However, there is no clear association between JCV presence in CNS and its ability to initiate CNS cancer and tumor formation in humans. In this review, we will discuss the correlation between JCV and tumorigenesis of CNS in animal models, and we will give an overview of the current evidence for the JC virus’s role in brain tumor formation.

LINC00689 participates in proliferation, chemoresistance and metastasis via miR-31-5p/YAP/β-catenin axis in colorectal cancer

As a kind of high-incidence malignant tumors in the digestive tract, colorectal cancer (CRC) has extremely morbidity and mortality in the population. LncRNAs have been proved to regulate the proliferation, chemoresistance and metastasis of tumors including CRC. LINC00689 and miR-31-5p in CRC were found misregulated in CRC by TCGA analysis. However, the mechanism of LINC00689 and miR-31-5p in regulating CRC remains unknown. The expression levels of LINC00689, miR-31-5p and LATS2 in CRC tissues and cell lines were examined by qRT-PCR assay. Cell proliferation, metastasis (including invasion and migration) were quantified by MTT assay, colony formation and Transwell assay, respectively. Western blotting assay was then performed to verify the levels of YAP/β-catenin and metastasis-related proteins. Dual-luciferase reporter assay and RIP assay were performed to evaluate the interaction between LINC00689 (LATS2) and miR-31-5p. Moreover, the function of LINC00689 and miR-31-5p were confirmed by CRC xenograft in nude mice. LINC00689 was decreased while miR-31-5p was increased in CRC. The overexpression of LINC00689 or the knockdown of miR-31-5p inhibited cell proliferation, chemoresistance and metastasis of CRC cells. Meanwhile, the up-regulated LATS2 suppressed the activity of YAP/β-catenin pathway to repress CRC occurrence. Silencing LATS2 reversed the inhibition effects of overexpression of LINC00689 or knockdown of miR-31-5p on proliferation, chemoresistance and metastasis of CRC cells. LINC00689 indeed acted as a miR-31-5p sponge to inhibit CRC proliferation, chemoresistance and metastasis through up-regulating LATS2 and repressing YAP/β-catenin signaling pathway.

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.

Intermittent hypoxia exacerbates tumor progression in a mouse model of lung cancer

The purpose of this study was to evaluate whether obstructive sleep apnea (OSA)-related chronic intermittent hypoxia (CIH) influences lung cancer progression and to elucidate the associated mechanisms in a mouse model of lung cancer. C57/BL6 mice in a CIH group were exposed to intermittent hypoxia for two weeks after tumor induction and compared with control mice (room air). Hypoxia inducible factor 1α (HIF-1α), vascular endothelial growth factor (VEGF) and metastasis-related matrix metalloproteinases (MMP) were measured. The expression levels of several hypoxia-related pathway proteins including HIF-1α, Wnt/ß-catenin, the nuclear factor erythroid 2-related factor 2 (Nrf2) and mammalian target of rapamycin-ERK were measured by western blot. The number (P < 0.01) and volume (P < 0.05) of tumors were increased in the CIH group. The activity of MMP-2 was enhanced after CIH treatment. The level of VEGF was increased significantly in the CIH group (p < 0.05). ß-catenin and Nrf2 were translocated to the nucleus and the levels of downstream effectors of Wnt/ß-catenin signaling increased after IH exposure. CIH enhanced proliferative and migratory properties of tumors in a mouse model of lung cancer. ß-catenin and Nrf2 appeared to be crucial mediators of tumor growth.

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.

JCPyV-Induced MAPK Signaling Activates Transcription Factors during Infection

JC polyomavirus (JCPyV), a ubiquitous human pathogen, is the etiological agent of the fatal neurodegenerative disease progressive multifocal leukoencephalopathy (PML). Like most viruses, JCPyV infection requires the activation of host-cell signaling pathways in order to promote viral replication processes. Previous works have established the necessity of the extracellular signal-regulated kinase (ERK), the terminal core kinase of the mitogen-activated protein kinase (MAPK) cascade (MAPK-ERK) for facilitating transcription of the JCPyV genome. However, the underlying mechanisms by which the MAPK-ERK pathway becomes activated and induces viral transcription are poorly understood. Treatment of cells with siRNAs specific for Raf and MAP kinase kinase (MEK) targets proteins in the MAPK-ERK cascade, significantly reducing JCPyV infection. MEK, the dual-specificity kinase responsible for the phosphorylation of ERK, is phosphorylated at times congruent with early events in the virus infectious cycle. Moreover, a MAPK-specific signaling array revealed that transcription factors downstream of the MAPK cascade, including cMyc and SMAD4, are upregulated within infected cells. Confocal microscopy analysis demonstrated that cMyc and SMAD4 shuttle to the nucleus during infection, and nuclear localization is reduced when ERK is inhibited. These findings suggest that JCPyV induction of the MAPK-ERK pathway is mediated by Raf and MEK and leads to the activation of downstream transcription factors during infection. This study further defines the role of the MAPK cascade during JCPyV infection and the downstream signaling consequences, illuminating kinases as potential therapeutic targets for viral infection.

Effect of the Large and Small T-Antigens of Human Polyomaviruses on Signaling Pathways

Viruses are intracellular parasites that require a permissive host cell to express the viral genome and to produce new progeny virus particles. However, not all viral infections are productive and some viruses can induce carcinogenesis. Irrespective of the type of infection (productive or neoplastic), viruses hijack the host cell machinery to permit optimal viral replication or to transform the infected cell into a tumor cell. One mechanism viruses employ to reprogram the host cell is through interference with signaling pathways. Polyomaviruses are naked, double-stranded DNA viruses whose genome encodes the regulatory proteins large T-antigen and small t-antigen, and structural proteins that form the capsid. The large T-antigens and small t-antigens can interfere with several host signaling pathways. In this case, we review the interplay between the large T-antigens and small t-antigens with host signaling pathways and the biological consequences of these interactions.

Human Polyomavirus JCPyV and Its Role in Progressive Multifocal Leukoencephalopathy and Oncogenesis

The human neurotropic virus JCPyV, a member of the Polyomaviridiae family, is the opportunistic infectious agent of Progressive Multifocal Leukoencephalopathy (PML), a fatal disease seen in severe immunosuppressive conditions and, during the last decade, in patients undergoing immunotherapy. JCPyV is a ubiquitous pathogen with up to 85% of the adult population word-wide exhibiting antibodies against it. Early experiments demonstrated that direct inoculation of JCPyV into the brain of different species resulted in the development of brain tumors and other neuroectodermal-derived neoplasias. Later, several reports showed the detection of viral sequences in medulloblastomas and glial tumors, as well as expression of the viral protein T-Antigen. Few oncogenic viruses, however, have caused so much controversy regarding their role in the pathogenesis of brain tumors, but the discovery of new Polyomaviruses that cause Merkel cell carcinomas in humans and brain tumors in racoons, in addition to the role of JCPyV in colon cancer and multiple mechanistic studies have shed much needed light on the role of JCPyV in cancer. The pathways affected by the viral protein T-Antigen include cell cycle regulators, like p53 and pRb, and transcription factors that activate pro-proliferative genes, like c-Myc. In addition, infection with JCPyV causes chromosomal damage and T-Antigen inhibits homologous recombination, and activates anti-apoptotic proteins, such as Survivin. Here we review the different aspects of the biology and physiopathology of JCPyV.

Human DNA Virus Exploitation of the MAPK-ERK Cascade

The extracellular signal-regulated kinases (ERKs) comprise a particular branch of the mitogen-activated protein kinase cascades (MAPK) that transmits extracellular signals into the intracellular environment to trigger cellular growth responses. Similar to other MAPK cascades, the MAPK-ERK pathway signals through three core kinases—Raf, MAPK/ERK kinase (MEK), and ERK—which drive the signaling mechanisms responsible for the induction of cellular responses from extracellular stimuli including differentiation, proliferation, and cellular survival. However, pathogens like DNA viruses alter MAPK-ERK signaling in order to access DNA replication machineries, induce a proliferative state in the cell, or even prevent cell death mechanisms in response to pathogen recognition. Differential utilization of this pathway by multiple DNA viruses highlights the dynamic nature of the MAPK-ERK pathway within the cell and the importance of its function in regulating a wide variety of cellular fates that ultimately influence viral infection and, in some cases, result in tumorigenesis.

Upregulated RACK1 attenuates gastric cancer cell growth and epithelial-mesenchymal transition via suppressing Wnt/β-catenin signaling

Purpose: As there have been few studies on the effects of the receptor for activated C kinase 1 (RACK1) on gastric cancer (GC), we aimed to explore such effects and the mechanism that may be involved.

Patients and methods: Normal gastric epithelial cells and six GC cell lines were used to detect the mRNA expression of RACK1. Overexpressing RACK1 was transfected in HGC27 and MGC803 cells. The effects of overexpressing RACK1 on cell viability, migration, and invasion were determined by cell counting kit-8, wound scratch, and Transwell assay, respectively. The expressions of epithelial–mesenchymal transition (EMT) and Wnt/β-catenin signaling related genes were detected using quantitative real-time PCR or Western blot. Wnt pathway agonist LiCl was added into RACK1 overexpressing GC cells, and then cell viability, migration, and invasion were also detected.

Results: RACK1 was downregulated in GC cell lines. Under the circumstance that overexpressing RACK1 was successfully transfected in the two lowest RACK1-expressing GC cells, significant inhibition of cell viability, migration, and invasion, promotion to the mRNA and protein expression of E-cadherin, as well as a decrease in the N-cadherin and Snail expressions could be observed. Overexpressing RACK1 also enhanced the protein level of phosphorylation-β-catenin/β-catenin and attenuated c-Jun protein expression. Additionally, LiCl could partially reverse the inhibitory effects of cell viability, migration and invasion by overexpressing RACK.

Conclusion: We found RACK1 possibly inhibited epithelial–mesenchymal transition of GC cells through limitation of the Wnt/β-catenin pathway, thereby suppressing cell migration and invasion; RACK1 could also suppress cell growth.

Extracellular Vesicles and Ebola Virus: A New Mechanism of Immune Evasion

Ebola virus (EBOV) disease can result in a range of symptoms anywhere from virtually asymptomatic to severe hemorrhagic fever during acute infection. Additionally, spans of asymptomatic persistence in recovering survivors is possible, during which transmission of the virus may occur. In acute infection, substantial cytokine storm and bystander lymphocyte apoptosis take place, resulting in uncontrolled, systemic inflammation in affected individuals. Recently, studies have demonstrated the presence of EBOV proteins VP40, glycoprotein (GP), and nucleoprotein (NP) packaged into extracellular vesicles (EVs) during infection. EVs containing EBOV proteins have been shown to induce apoptosis in recipient immune cells, as well as contain pro-inflammatory cytokines. In this manuscript, we review the current field of knowledge on EBOV EVs including the mechanisms of their biogenesis, their cargo and their effects in recipient cells. Furthermore, we discuss some of the effects that may be induced by EBOV EVs that have not yet been characterized and highlight the remaining questions and future directions.

Molecular survey on Merkel cell polyomavirus in patients with colorectal cancer

Background: Merkel cell polyomavirus (MCV) has been associated with Merkel cell carcinoma (MCC) in humans, and its role in other human cancers is under investigation. The aim of this study was to investigate MCV genome infection in patients with colorectal cancer (CRC).Methods: This retrospective, case-control study used archived formalin-fixed, paraffin-embedded (FFPE) tissue samples from colorectal cancer patients (cases) and matched healthy subjects (controls) diagnosed by an expert pathologist from hospitals affiliated with Iran University of Medical Sciences, Tehran, Iran from 2011 to 2016. After DNA extraction with a QIAamp® DNA FFPE Tissue Kit, real-time polymerase chain reaction (PCR) was used for diagnosis. A positive control was produced by cloning with the Generay Biotechnology system. SPSS v.22 was used for analysis of demographic variables.Results: There were 157 participants included in the study: 66 were cases and 91 were controls. Their mean ages (±SD) were 59.35±14.48 and 57.21±14.66, respectively. The proportion of males was 57.6% in the case group and 57.1% in the control group. None of the samples were positive for MCV expression by real-time PCR assay. Association was detected between males with CRC and tumor location in the rectum and between males with CRC and the mucinous tumor type.Conclusion: None of the tissues from the CRC or non-cancerous control groups were positive for MCV genome infection, although a low viral load, the sample type, or the method of use should not be neglected. Further studies are recommended to obtain more comprehensive results.

Ebola Virus VP40 Modulates Cell Cycle and Biogenesis of Extracellular Vesicles

Background

Ebola virus (EBOV) mainly targets myeloid cells; however, extensive death of T cells is often observed in lethal infections. We have previously shown that EBOV VP40 in exosomes causes recipient immune cell death.

Methods

Using VP40-producing clones, we analyzed donor cell cycle, extracellular vesicle (EV) biogenesis, and recipient immune cell death. Transcription of cyclin D1 and nuclear localization of VP40 were examined via kinase and chromatin immunoprecipitation assays. Extracellular vesicle contents were characterized by mass spectrometry, cytokine array, and western blot. Biosafety level-4 facilities were used for wild-type Ebola virus infection studies.

Results

VP40 EVs induced apoptosis in recipient T cells and monocytes. VP40 clones were accelerated in growth due to cyclin D1 upregulation, and nuclear VP40 was found bound to the cyclin D1 promoter. Accelerated cell cycling was related to EV biogenesis, resulting in fewer but larger EVs. VP40 EV contents were enriched in ribonucleic acid-binding proteins and cytokines (interleukin-15, transforming growth factor-β1, and interferon-γ). Finally, EBOV-infected cell and animal EVs contained VP40, nucleoprotein, and glycoprotein.

Conclusions

Nuclear VP40 upregulates cyclin D1 levels, resulting in dysregulated cell cycle and EV biogenesis. Packaging of cytokines and EBOV proteins into EVs from infected cells may be responsible for the decimation of immune cells during EBOV pathogenesis.

Growth hormone-releasing hormone receptor antagonists modify molecular machinery in the progression of prostate cancer

BACKGROUND

Therapeutic strategies should be designed to transform aggressive prostate cancer phenotypes to a chronic situation. To evaluate the effects of the new growth hormone-releasing hormone receptor (GHRH-R) antagonists: MIA-602, MIA-606, and MIA-690 on processes associated with cancer progression as cell proliferation, adhesion, migration, and angiogenesis.

METHODS

We used three human prostate cell lines (RWPE-1, LNCaP, and PC3). We analyzed several molecules such as E-cadherin, β-catenin, Bcl2, Bax, p53, MMP2, MMP9, PCNA, and VEGF and signaling mechanisms that are involved on effects exerted by GHRH-R antagonists.

RESULTS

GHRH-R antagonists decreased cell viability and provoked a reduction in proliferation in LNCaP and PC3 cells. Moreover, GHRH-R antagonists caused a time-dependent increase of cell adhesion in all three cell lines and retarded the wound closure with the highest value with MIA-690 in PC3 cells. GHRH-R antagonists also provoked a large number of cells in SubG₀ phase revealing an increase in apoptotic cells in PC3 cell line.

CONCLUSIONS

Taken all together, GHRH-R antagonists of the MIAMI series appear to be inhibitors of tumor progression in prostate cancer and should be considered for use in future therapeutic strategies on this malignancy.

Serum IgG antibodies from healthy subjects up to 100 years old react to JC polyomavirus

JC polyomavirus (JCPyV) was identified in 1971 in the brain tissue of a patient (J.C.) affected by the progressive multifocal leukoencephalopathy (PML). JCPyV encodes for the oncoproteins large T antigen (Tag) and small t-antigen (tag). These oncoproteins are responsible of the cell transformation and tumorigenesis in experimental animals. JCPyV is ubiquitous in human populations. After the primary infection, which is usually asymptomatic, JCPyV remains lifelong in the host in a latent phase. Its reactivation may occur in heathy subjects and immunocompromised patients. Upon reactivation, JCPyV could reach (i) the CNS inducing the PML, (ii) the kidney of transplant patients causing the organ rejection. Association between JCPyV, which is a small DNA tumor virus, and gliomas and colorectal carcinomas has been published. In the present investigation, we report on a new indirect ELISA with two specific synthetic peptides mimicking JCPyV VP1 immunogenic epitopes to detect specific serum IgG antibodies against JCPyV. Serum samples of healthy subjects (n = 355) ranging 2-100 years old, were analyzed by this new indirect ELISA. The linear peptides VP1 K and VP1 N resemble the natural JCPyV VP1 capsidic epitopes constituting a docking site for serum antibodies. Data from this innovative immunologic assay indicate that the overall prevalence of JCPyV-VP1 antibodies in healthy subjects is at 39%. The innovative indirect ELISA with JCPyV VP1 mimotopes seems to be a useful method to detect specific IgG antibodies against this virus, without cross-reactivity with the closely related SV40 and BKPyV polyomaviruses.

Colon cancers carrying BRAF V600E and β-catenin T41A activating mutations are resistant to numerous common anticancer drugs

Colorectal cancer is a common malignancy with a high prevalence and associated mortality rate. However, the preclinical tools currently used for drug development are insufficient. The aim of the present study was to establish and characterize a specific patient-derived colon cancer xenograft (PDCCX) mouse model for drug testing. Primary colon tumors were obtained from 10 patients by surgical resection, and tumor tissues were subsequently grafted into nude mice followed by consecutive passages. Primary tumors and xenograft tumors were collected and processed for DNA sequencing, histological evaluation and immunohistochemical staining. The responses of fifth-generation PDCCX mice to 5-fluorouracil, oxaliplatin, and cetuximab were assessed. Two PDCCX cell lines were successfully established. The histology and protein expression levels of SMAD family member 3, epidermal growth factor receptor, c-MET, caudal type homeobox 2, E-cadherin and β-catenin in the xenograft tumors were consistently maintained from the primary cancer tissues. BRAF V600E and β-catenin T41A double mutations were identified in one cell line, and were associated with a lack of response to 5-fluorouracil, oxaliplatin and cetuximab treatment. This PDCCX cell line may provide a reliable tool for preclinical evaluation of the efficacy of novel therapies that may target the BRAF V600E and β-catenin mutations.

Human Polyomaviruses: The Battle of Large and Small Tumor Antigens

About 40 years ago, the large and small tumor antigens (LT-Ag and sT-Ag) of the polyomavirus (PyVs) simian vacuolating virus 40 have been identified and characterized. To date, it is well known that all the discovered human PyVs (HPyVs) encode these 2 multifunctional and tumorigenic proteins, expressed at viral replication early stage. The 2 T-Ags are able to transform cells both in vitro and in vivo and seem to play a distinct role in the pathogenesis of some tumors in humans. In addition, they are involved in viral DNA replication, transcription, and virion assembly. This short review focuses on the structural and functional features of the HPyVs’ LT-Ag and sT-Ag, with special attention to their transforming properties.

T cell therapies for human polyomavirus diseases

Rapid restoration of virus-specific T immunity via adoptive transfer of ex vivo generated T cells has been proven as a powerful therapy for patients with advanced cancers and refractory viral infections such as cytomegalovirus (CMV) and Epstein-Barr virus (EBV). BK virus (BKV), John Cunningham virus (JCV), and Merkel cell carcinoma virus (MCV) are the members of the rapidly growing human polyomavirus (hPyV) family that commonly infects most healthy humans. These viruses have a clearly established potential for causing severe end-organ damage or malignant transformation, especially in individuals with weakened immunity who are unable to mount or regain endogenous T-cell responses as a result of underlying leukemia or iatrogenic immunosuppression in autoimmunity, bone marrow and solid organ transplant settings. Here we will discuss recent advances in using T-cell-based immunotherapies to save patients suffering from PyV-associated diseases including hemorrhagic cystitis, BKV virus-associated nephropathy, and JC-associated progressive multifocal leukoencephalopathy (PML). We will also review progress in the understanding of Merkel cell carcinoma (MCC) as a virally driven tumor that is amenable to immune intervention and can be targeted with adoptively transferred T cells specific for viral oncoproteins.

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.

Liver serine palmitoyltransferase activity deficiency in early life impairs adherens junctions and promotes tumorigenesis

Serine palmitoyltransferase is the key enzyme in sphingolipid biosynthesis. Mice lacking serine palmitoyltransferase are embryonic lethal. We prepared liver-specific mice deficient in the serine palmitoyltransferase long chain base subunit 2 gene using an albumin-cyclization recombination approach and found that the deficient mice have severe jaundice. Moreover, the deficiency impairs hepatocyte polarity, attenuates liver regeneration after hepatectomy, and promotes tumorigenesis. Importantly, we show that the deficiency significantly reduces sphingomyelin but not other sphingolipids in hepatocyte plasma membrane; greatly reduces cadherin, the major protein in adherens junctions, on the membrane; and greatly induces cadherin phosphorylation, an indication of its degradation. The deficiency affects cellular distribution of β-catenin, the central component of the canonical Wnt pathway. Furthermore, such a defect can be partially corrected by sphingomyelin supplementation in vivo and in vitro.

CONCLUSION

The plasma membrane sphingomyelin level is one of the key factors in regulating hepatocyte polarity and tumorigenesis. (Hepatology 2016;64:2089-2102).

Circular RNA-ITCH Suppresses Lung Cancer Proliferation via Inhibiting the Wnt/β-Catenin Pathway

As a special form of noncoding RNAs, circular RNAs (circRNAs) played important roles in regulating cancer progression mainly by functioning as miRNA sponge. While the function of circular RNA-ITCH (cir-ITCH) in lung cancer is still less reported, in this study, we firstly detected the expression of cir-ITCH in tumor tissues and paired adjacent noncancer tissues of 78 patients with lung cancer using a TaqMan-based quantitative real-time PCR (qRT-PCR). The results showed that the expression of cir-ITCH was significantly decreased in lung cancer tissues. In cellular studies, cir-ITCH was also enhanced in different lung cancer cell lines, A549 and NIC-H460. Ectopic expression of cir-ITCH markedly elevated its parental cancer-suppressive gene, ITCH, expression and inhibited proliferation of lung cancer cells. Molecular analysis further revealed that cir-ITCH acted as sponge of oncogenic miR-7 and miR-214 to enhance ITCH expression and thus suppressed the activation of Wnt/β-catenin signaling. Altogether, our results suggested that cir-ITCH may play an inhibitory role in lung cancer progression by enhancing its parental gene, ITCH, expression.

The oncogenic role of JC virus T antigen in lens tumors without cell specificity of alternative splicing of its intron

JC virus (JCV), a ubiquitous polyoma virus that commonly infects the human, is identified as the etiologic agent for progressive multifocal leukoencephalopathy and some malignancies. To clarify the oncogenic role of JCV T antigen, we established two transgenic mice of T antigen using either α-crystallin A (αAT) or cytokeratin 19(KT) promoter. Lens tumors were found in high-copy αAT mice with the immunopositivity of T antigen, p53, β-catenin and N-cadherin. Enlarged eyeballs were observed and tumor invaded into the brain by magnetic resonance imaging and hematoxylin-and-eosin staining. The overall survival time of homozygous mice was shorter than that of hemizygous mice (p<0.01), the latter than wild-type mice (p<0.01). The spontaneous salivary tumor and hepatocellular carcinoma were seen in αAT5 transgenic mice with no positivity of T antigen. KT7 mice suffered from lung tumor although JCV T antigen was strongly expressed in gastric epithelial cells. The alternative splicing of T antigen intron was detectable in the lens tumor of αAT mice, gastric mucosa of KT mice, and various cells transfected with pEGFP-N1-T antigen. It was suggested that JCV T antigen might induce carcinogenesis at a manner of cell specificity, which is not linked to alternative splicing of its intron. Both spontaneous lens and lung tumor models provide good tools to investigate the oncogenic role of JCV T antigen.

Complex Behavior of ALDH1A1 and IGFBP1 in Liver Metastasis from a Colorectal Cancer

Using our data set (GSE50760) previously established by RNA sequencing, the present study aimed to identify upregulated genes associated with colorectal cancer (CRC) liver metastasis (CLM) and verify their biological behavior. The potential roles of candidate genes in tumors were assessed using cell proliferation and invasion assays. Tissue samples were collected from 18 CRC patients with synchronous CLM and two CRC cell lines (SW480 and SW620) were used for transfection and cloning. The roles of the genes identified in CLM were verified using immunohistochemistry in 48 nude mice after intrasplenic transplantation of CRC cells. mRNA and protein expression was determined by quantitative real-time reverse transcription polymerase chain reaction and western blot, respectively. Nine genes were initially selected according to the relevance of their molecular function and biological process and, finally, ALDH1A1 and IGFBP1 were chosen based on differential mRNA expression and a positive correlation with protein expression. The overexpression of ALDH1A1 and IGFBP1 significantly and time-dependently decreased cell proliferation (p ≤ 0.001–0.003) and suppressed invasiveness by ≥3-fold over control cells (p < 0.001) in the SW480 cell line, whereas they had a slight effect on reducing SW620 cell proliferation. The protein expression levels of E-cadherin, N-cadherin, claudin-1, and vimentin were significantly higher in CLM than in primary tumor tissues (p < 0.05). However, the cadherin switch, namely, N-cadherin overexpression with reduced E-cadherin expression, was not observed in CLM tissues and transfected CRC cells. Irrespective of reduced proliferation and invasion found on in vitro cell assays, persistent overexpression of β-catenin, vimentin, and ZO-1 in IGFBP1-overexpressing SW480 cells possibly contributed to CLM development in mice implanted with IGFBP1-overexpressing SW480 cells (CLM occurrences: SW480/IGFBP1-transfected mice vs. SW480/vector- and SW480/ALDH1A1-transfected mice, 4/8 vs. 0/10, p = 0.023). In conclusion, ALDH1A1 and IGFBP1 are differentially overexpressed in CLM and may play a dual role, functioning as both tumor suppressors and metastasis promoters in CRC.

Shizukaol D, a Dimeric Sesquiterpene Isolated from Chloranthus serratus, Represses the Growth of Human Liver Cancer Cells by Modulating Wnt Signalling Pathway

Natural products have become sources of developing new drugs for the treatment of cancer. To seek candidate compounds that inhibit the growth of liver cancer, components of Chloranthus serratus were tested. Here, we report that shizukaol D, a dimeric sesquiterpene from Chloranthus serratus, exerted a growth inhibition effect on liver cancer cells in a dose- and time-dependent manner. We demonstrated that shizukaol D induced cells to undergo apoptosis. More importantly, shizukaol D attenuated Wnt signalling and reduced the expression of endogenous Wnt target genes, which resulted in decreased expression of β-catenin. Collectively, this study demonstrated that shizukaol D inhibited the growth of liver cancer cells by modulating Wnt pathway.

Simian virus 40 is not likely involved in the development of colorectal adenocarcinoma

Aim: The purpose of this study is to investigate the role of simian virus 40 (SV40) in colorectal cancer development by assessing the presence of DNA and protein product of SV40 in colorectal cancer. Materials & methods: Extracted DNA from 83 archival colorectal adenocarcinoma samples and 35 control samples of noncancerous colon tissue was analyzed for SV40 using PCR-based techniques. The expression of the protein product was assessed using immunohistochemical staining. Results: All tested tumors and control cases failed to detect SV40 DNA in PCR assays. Furthermore, immunohistochemical staining did not show any viral proteins in both cancer and control cases. Conclusion: These results indicated that there is no association between SV40 and the development of colorectal adenocarcinomas.

A systematic investigation based on microRNA-mediated gene regulatory network reveals that dysregulation of microRNA-19a/Cyclin D1 axis confers an oncogenic potential and a worse prognosis in human hepatocellular carcinoma

MicroRNAs (miRNAs) contribute to a wide variety of human diseases by regulating gene expression, leading to imbalances in gene regulatory networks. To discover novel hepatocellular carcinoma (HCC)-related miRNA-target axes and to elucidate their functions, we here performed a systematic investigation combining biological data acquisition and integration, miRNA-target prediction, network construction, functional assay and clinical validation. As a result, a total of 117 HCC differentially expressed miRNAs were identified, and 728 high confident target genes of these miRNAs were collected. Then, the interaction network of target genes was constructed and 221 key nodes with topological importance in the network were identified according to their topological features including degree, node-betweenness, closeness and K-coreness. Among these key nodes, Cyclin D1 had the highest node-betweenness, implying its bottleneck role in the network. Luciferase reporter assay confirmed that miRNA-19a, which was one of HCC downregulated miRNAs, directly targeted Cyclin D1 in HCC cells. Moreover, miR-19a might play inhibitory roles in HCC malignancy via regulating Cyclin D1 expression. Further clinical evidence also highlighted the prognostic potential of miR-19a/Cyclin D1 axis in HCC. In conclusion, this systematic investigation provides a framework to identify featured miRNAs and their target genes which are potent effectors in the occurrence and development of HCC. More importantly, miR-19a/Cyclin D1 axis might have promising applications as a therapeutic target and a prognostic marker for patients with HCC.

Astaxanthin induces angiogenesis through Wnt/β-catenin signaling pathway

OBJECTIVE

In the present study, we sought to elucidate whether astaxanthin contributes to induce angiogenesis and its mechanisms.

MATERIALS AND METHODS

To this end, we examined the role of astaxanthin on human brain microvascular endothelial cell line (HBMEC) and rat aortic smooth muscle cell (RASMC) proliferation, invasion and tube formation in vitro. For study of mechanism, the Wnt/β-catenin signaling pathway inhibitor IWR-1-endo was used. HMBECs and RASMCs proliferation were tested by cell counting. Scratch adhesion test was used to assess the ability of invasion. A matrigel tube formation assay was performed to test capillary tube formation ability. The Wnt/β-catenin pathway activation in HMBECs and RASMCs were tested by Western blot.

RESULTS

Our data suggested that astaxanthin induces angiogenesis by increasing proliferation, invasion and tube formation in vitro. Wnt and β-catenin expression were increased by astaxanthin and counteracted by IWR-1-endo in HMBECs and RASMCs. Tube formation was increased by astaxanthin and counteracted by IWR-1-endo.

CONCLUSIONS

It may be suggested that astaxanthin induces angiogenesis in vitro via a programmed Wnt/β-catenin signaling pathway.

Prostaglandin E2 promotes human cholangiocarcinoma cell proliferation, migration and invasion through the upregulation of β-catenin expression via EP3-4 receptor

Prostaglandin E2 (PGE2) is involved in cholangiocarcinoma cell proliferation, migration and invasion through E prostanoid receptors, including EP1, EP2 and EP4. However, the functions and the mechanisms of those splice variants of EP3 receptors in promoting liver cancer cell growth and invasion remain to be elucidated. In our previous studies, four isoforms of EP3 receptors, EP3-4, EP3-5, EP3-6 and EP3-7 receptors, were detected in CCLP1 and HuCCT1 cells. However, the functions of these receptors in these cells have yet to be determined. It was reported that β-catenin is closely correlated with malignancy, including cholangiocarcinoma. The present study was designed to examine the effects of 4-7 isoforms of EP3 in promoting cholangiocarcinoma progression and the mechanisms by which PGE2 increases β-catenin protein via EP3 receptors. The results showed that PGE2 promotes cholangiocarcinoma progression via the upregulation of β-catenin protein, and the EP3-4 receptor pathway is mainly responsible for this regulation. These findings reveal that PGE2 upregulated the cholangiocarcinoma cell β-catenin protein through the EP3-4R/Src/EGFR/PI3K/AKT/GSK-3β pathway. The present study identified the functions of EP3 and the mechanisms by which PGE2 regulates β-catenin expression and promoted cholangiocarcinoma cell growth and invasion.