MLKL Requires the Inositol Phosphate Code to Execute Necroptosis.

Necroptosis is an important form of lytic cell death triggered by injury and infection, but whether mixed lineage kinase domain-like (MLKL) is sufficient to execute this pathway is unknown. In a genetic selection for human cell mutants defective for MLKL-dependent necroptosis, we identified mutations in IPMK and ITPK1, which encode inositol phosphate (IP) kinases that regulate the IP code of soluble molecules. We show that IP kinases are essential for necroptosis triggered by death receptor activation, herpesvirus infection, or a pro-necrotic MLKL mutant. In IP kinase mutant cells, MLKL failed to oligomerize and localize to membranes despite proper receptor-interacting protein kinase-3 (RIPK3)-dependent phosphorylation. We demonstrate that necroptosis requires IP-specific kinase activity and that a highly phosphorylated product, but not a lowly phosphorylated precursor, potently displaces the MLKL auto-inhibitory brace region. These observations reveal control of MLKL-mediated necroptosis by a metabolite and identify a key molecular mechanism underlying regulated cell death.

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.

Type I interferon signaling attenuates regulatory T cell function in viral infection and in the tumor microenvironment.

Regulatory T cells (Tregs) play a cardinal role in the immune system by suppressing detrimental autoimmune responses, but their role in acute, chronic infectious diseases and tumor microenvironment remains unclear. We recently demonstrated that IFN-α/ß receptor (IFNAR) signaling promotes Treg function in autoimmunity. Here we dissected the functional role of IFNAR-signaling in Tregs using Treg-specific IFNAR deficient (IFNARfl/flxFoxp3YFP-Cre) mice in acute LCMV Armstrong, chronic Clone-13 viral infection, and in tumor models. In both viral infection and tumor models, IFNARfl/flxFoxp3YFP-Cre mice Tregs expressed enhanced Treg associated activation antigens. LCMV-specific CD8+ T cells and tumor infiltrating lymphocytes from IFNARfl/flxFoxp3YFP-Cre mice produced less antiviral and antitumor IFN-γ and TNF-α. In chronic viral model, the numbers of antiviral effector and memory CD8+ T cells were decreased in IFNARfl/flxFoxp3YFP-Cre mice and the effector CD4+ and CD8+ T cells exhibited a phenotype compatible with enhanced exhaustion. IFNARfl/flxFoxp3YFP-Cre mice cleared Armstrong infection normally, but had higher viral titers in sera, kidneys and lungs during chronic infection, and higher tumor burden than the WT controls. The enhanced activated phenotype was evident through transcriptome analysis of IFNARfl/flxFoxp3YFP-Cre mice Tregs during infection demonstrated differential expression of a unique gene signature characterized by elevated levels of genes involved in suppression and decreased levels of genes mediating apoptosis. Thus, IFN signaling in Tregs is beneficial to host resulting in a more effective antiviral response and augmented antitumor immunity.

Epstein-Barr virus-positive inflammatory follicular dendritic cell sarcoma presenting as a solitary colonic mass: two rare cases and a literature review.

AIMS: Follicular dendritic cell (FDC) sarcoma is a rare neoplasm originating from follicular dendritic cells in germinal centres. It is classified as conventional and Epstein-Barr virus (EBV)-positive inflammatory FDC sarcoma according to the 2019 World Health Organization classification of digestive system tumours; the latter is rarer. So in view of the rarity and difficulty in diagnosis, the aim of the manuscript is to share our experience of diagnosing EBV-positive inflammatory FDC sarcoma. METHODS AND RESULTS: Here, we describe the clinicopathological features, gross description, histomorphology, immunophenotype, EBV-encoded mRNA (EBER) in-situ hybridisation, gene rearrangement and clinical follow-up of two patients with EBV-positive inflammatory FDC sarcoma in the colon, and review the relevant literature. The tumours were found in two males, aged 53 and 48 years, respectively, with a tumour diameter between 10 and 45 mm. Both cases occurred in the colon and presented as pedunculated colonic masses. Microscopically, scanty atypical ovoid to spindle neoplastic cells were mixed in a background of florid lymphoplasmacytic infiltration. The nuclei of these atypical cells showed vesicular chromatin and small, distinct nucleoli. Immunohistochemistry demonstrated that the atypical stromal cells were positive for CD21, CD23, CD35, and D2-40. EBER in-situ hybridisation also gave positive results in two cases. There was a mean follow-up of 9 months (range, 7-11 months). CONCLUSION: EBV-positive inflammatory FDC sarcoma is an extremely rare tumour with a distinct morphology and phenotype. Therefore, it is very important to recognise it particularly for correct diagnosis and prevention of misdiagnosis and mistreatment.

Vitamin D as a Primer for Oncolytic Viral Therapy in Colon Cancer Models.

Oncolytic viroimmunotherapy is an exciting modality that can offer lasting anti-tumor immunity for aggressive malignancies like colon cancer. The impact of oncolytic viruses may be extended by combining them with agents to prime a tumor for viral susceptibility. This study investigates vitamin D analogue as an adjunct to oncolytic viral therapy for colon cancer. While vitamin D (VD) has historically been viewed as anti-viral, our in vitro investigations using human colon cancer cell lines showed that VD does not directly inhibit replication of recombinant chimeric poxvirus CF33. VD did restrict growth in HT29 but not HCT116 human colon cancer cells. In vivo investigations using HCT116 and HT29 xenograft models of colon cancer demonstrated that a VD analogue, calcipotriol, was additive with CF33-based viral therapy in VD-responsive HT29 but not in HCT116 tumors. Analyses of RNA-sequencing and gene expression data demonstrated a downregulation in the Jak-STAT signaling pathway with the addition of VD to viral therapy in HT29 models suggesting that the anti-inflammatory properties of VD may enhance the effects of viral therapy in some models. In conclusion, VD may prime oncolytic viral therapy in certain colon cancers.

Fascin1 suppresses RIG-I-like receptor signaling and interferon-ß production by associating with IκB kinase ϵ (IKKϵ) in colon cancer.

Fascin1 is an actin-bundling protein involved in cancer cell migration and has recently been shown also to have roles in virus-mediated immune cell responses. Because viral infection has been shown to activate immune cells and to induce interferon-ß expression in human cancer cells, we evaluated the effects of fascin1 on virus-dependent signaling via the membrane- and actin-associated protein RIG-I (retinoic acid-inducible gene I) in colon cancer cells. We knocked down fascin1 expression with shRNA retrovirally transduced into a DLD-1 colon cancer and L929 fibroblast-like cell lines and used luciferase reporter assays and co-immunoprecipitation to identify fascin1 targets. We found that intracellular poly(I·C) transfection to mimic viral infection enhances the RIG-I/MDA5 (melanoma differentiation-associated gene 5)-mediated dimerization of interferon regulatory factor 3 (IRF-3). The transfection also significantly increased the expression levels of IRF-7, interferon-ß, and interferon-inducible cytokine IP-10 in fascin1-deleted cells compared with controls while significantly suppressing cell growth, migration, and invasion. We also found that fascin1 constitutively interacts with IκB kinase ϵ (IKKϵ) in the RIG-I signaling pathway. In summary, we have identified fascin1 as a suppressor of the RIG-I signaling pathway associating with IκB kinase ϵ in DLD-1 colon cancer cells to suppress immune responses to viral infection.

Virotherapy: Current Trends and Future Prospects for Treatment of Colon and Rectal Malignancies.

Colorectal cancer (CRC) is one of the most common malignancies. In recent decades, early diagnosis and conventional therapies have resulted in a significant reduction in mortality. However, late stage metastatic disease still has very limited effective treatment options. There is a growing interest in using viruses to help target therapies to tumour sites. In recent years the evolution of immunotherapy has emphasised the importance of directing the immune system to eliminate tumour cells; we aim to give a state-of-the-art over-view of the diverse viruses that have been investigated as potential oncolytic agents for the treatment of CRC.

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.

Prognostic differences between lymphoepithelioma-like colon carcinoma and colon adenocarcinoma.

Lymphoepithelioma-like colon carcinoma (LELC) is rare. The Epstein-Barr virus (EBV) hasn´t been implicated in the pathogenesis of LELC of the colon, but they may in fact be more strongly associated with MSI. Its treatment is identical to adenocarcinoma. However, lymphocyte infiltration and microsatellite instability have been associated with better prognosis.

Increased risk of non-AIDS-defining cancers in Asian HIV-infected patients: a long-term cohort study.

BACKGROUND: Data on the long-term risks of non-AIDS defining cancers (NADCs) are limited, especially in Asians. The incidence of NADCs may correlate with the epidemiological trend of cancers or oncogenic infection in each country, and thus the target cancers would be different between Western and Asian countries. We aimed to elucidate the incidence of NADCs and its predictive factors in Asian HIV-infected patients. METHODS: Subjects were HIV-infected patients (n = 1001) periodically followed-up for 9 years on average. NADCs were diagnosed by histopathology and/ or imaging findings. Standardized incidence ratios (SIR) were calculated as the ratio of the observed to expected number of NADCs for comparison with an age-and sex-matched general population. Cox's proportional hazards model was used to estimate hazard ratios (HR). RESULTS: During the median follow-up of 9 years, the 10-year cumulative incidence of NADCs was 6.4%.At NADC diagnosis, half of patients presented at age 40-59 years and with advanced tumor stage. Compared with the age-and sex-matched general population, HIV-infected patients are at increased risk for liver cancer (SIR, 4.7), colon cancer (SIR, 2.1), and stomach cancer (SIR, 1.8). In multivariate analysis, a predictive model for NADCs was developed that included age group (40-49, 50-59, 60-69, and ≥ 70 years), smoker, HIV infection through blood transmission, and injection drug use (IDU), and HBV co-infection. The c-statistic for the NADCs predictive model was 0.8 (95%CI, 0.8-0.9, P < 0.001). The higher 10-year incidence rate of NADCs was associated with increasing prediction score. CONCLUSIONS: Liver and colon cancer risk was elevated in Asian HIV-infected individuals, similar to in Western populations, whereas stomach cancer risk was characteristically elevated in Asian populations. Half of Asian NADC patients were aged 40-59 years and had advanced-stage disease at diagnosis. Periodic cancer screening may be warranted for high-risk subpopulations with smoking habit, HIV infection through blood transmission or IDU, and HBV co-infection, and screening should be started over 40 years of age.

Rotavirus-induced miR-142-5p elicits proviral milieu by targeting non-canonical transforming growth factor beta signalling and apoptosis in cells.

MicroRNA (miRNA) expression is significantly influenced by viral infection, because of either host antiviral defences or proviral factors resulting in the modulation of viral propagation. This study was undertaken to identify and analyse the significance of cellular miRNAs during rotavirus (SA11 or KU) infection. Sixteen differentially regulated miRNAs were identified during rotavirus infection of which hsa-miR-142-5p was up-regulated and validated by quantitative polymerase chain reaction. Exogenous expression of miR-142-5p inhibitor resulted in a significant reduction of viral titer indicating proviral role of miR-142-5p. Functional studies of hsa-miR-142-5p identified its role in transforming growth factor beta (TGFß) signalling as TGFß receptor 2 and SMAD3 were degraded during both hsa-miR-142-5p overexpression and rotavirus infection. TGFß is induced during rotavirus infection, which may promote apoptosis by activation of non-canonical pathways in HT29 cells. However, up-regulated miR-142-5p resulted in the inhibition of TGFß-induced apoptosis suggesting its anti-apoptotic function. Rotavirus NSP5 was identified as a regulator of miR-142-5p expression. Concurrently, NSP5-HT29 cells showed inhibition of TGFß-induced apoptosis and epithelial to mesenchymal transition by blocking non-canonical pathways. Overall, the study identified proviral function of hsa-miR-142-5p during rotavirus infection. In addition, modulation of TGFß-induced non-canonical signalling in microsatellite stable colon cancer cells can be exploited for cancer therapeutics.

[The prevalence of human papillomaviruses in patients with colon polyps].

INTRODUCTION: Potential role of HPV infection in pathogenesis of colon polyps and cancer remains undetermined. The aim of the study was to investigate the prevalence of DNA of HPV- 6, -11, -16 and -18 in the biopsies from colon polyps. MATERIAL AND METHODS: We investigated the biopsies from 24 patients (23 from colon polyps and I from colon cancer) of Department of Gastroenterology Medical University of Warsaw using Real time PCR HPV-6/11. Real-TM (Sacace Biotechnologies) was performed on termocycler Smart Cycler Dx. RESULTS: We didn't detect oncogenic HPV16 and HPV18 in any of the investigated specimens, HPV-11 was present in 11 patients including all patients with adenoma tubule-villosum. We detect HPV6 in 5 samples from polyps and 1 from colon cancer. CONCLUSIONS: HPV 6 and HPV 11 could play a role in pathogenesis some colon polyps but the final conclusions demand further investigations. Oncogenic HPV 16 and 18 probably don't play any role in colon polyps pathogenesis.

Treatment of colon cancer with oncolytic herpes simplex virus in preclinical models.

Cancer stem cells (CSCs), which are a rare population in any type of cancer, including colon cancer, are tumorigenic and responsible for cancer recurrence and metastasis. CSCs have been isolated from a number of different solid tumors recently, although the isolation of CSCs in colon cancer is still challenging. We cultured colon cancer cells in stem cell medium to obtain colonosphere cells. These cells possessed the characteristics of CSCs, with a high capacity of tumorigenicity, migration and invasion in vitro and in vivo. The isolation and identification of CSCs have provided new targets for the therapeutics. Oncolytic herpes simplex viruses (oHSV) are an effective strategy for killing colon cancer cells in preclinical models. Here, we examined the efficacy of an oncolytic herpes simplex virus type 2 (oHSV2) in killing colon cancer cells and colon cancer stem-like cells (CSLCs). oHSV2 was found to be highly cytotoxic to the adherent and sphere cells in vitro, and oHSV2 treatment in vivo significantly inhibited tumor growth. This study demonstrates that oHSV2 is effective against colon cancer cells and colon CSLCs and could be a promising strategy for treating colon cancer patients.

Combined therapy with CTL cells and oncolytic adenovirus expressing IL-15-induced enhanced antitumor activity.

Addition of immunoregulation factor to an oncolytic adenovirus being constructed is a developmental step in tumor gene therapy; however, cytokine IL-15 has not been frequently used as a potential cancer therapy agent. Here, we constructed an E2F-1 promoter oncolytic adenovirus based on type 5 adenovirus, which induces viral replication and proliferation in targeted tumor cells. We inserted the IL-15 gene into the E3 region of the model and found that human IL-15 expressing oncolytic adenovirus (Ad-E2F/IL15) shows a more intense antitumor effect than simple oncolytic viruses (Ad-E2F) do. Precisely because IL-15 can activate natural killer (NK) cells, CD8(+)T cells, and other immune cells, in antitumor therapy, Ad-E2F/IL15 was used in combination with cytotoxic T lymphocytes (CTL) to create a virus that can induce IL-15 gene expression while lysing tumors and stimulating the activity and function of adoptive immune cells. The therapeutic effect of this therapy is clearly stronger than that of a single application of oncolytic viruses or CTL, and hence, it could be a potential new tumor therapy.

Specific Colon Cancer Cell Cytotoxicity Induced by Bacteriophage E Gene Expression under Transcriptional Control of Carcinoembryonic Antigen Promoter.

Colorectal cancer is one of the most prevalent cancers in the world. Patients in advanced stages often develop metastases that require chemotherapy and usually show a poor response, have a low survival rate and develop considerable toxicity with adverse symptoms. Gene therapy may act as an adjuvant therapy in attempts to destroy the tumor without affecting normal host tissue. The bacteriophage E gene has demonstrated significant antitumor activity in several cancers, but without any tumor-specific activity. The use of tumor-specific promoters may help to direct the expression of therapeutic genes so they act against specific cancer cells. We used the carcinoembryonic antigen promoter (CEA) to direct E gene expression (pCEA-E) towards colon cancer cells. pCEA-E induced a high cell growth inhibition of human HTC-116 colon adenocarcinoma and mouse MC-38 colon cancer cells in comparison to normal human CCD18co colon cells, which have practically undetectable levels of CEA. In addition, in vivo analyses of mice bearing tumors induced using MC-38 cells showed a significant decrease in tumor volume after pCEA-E treatment and a low level of Ki-67 in relation to untreated tumors. These results suggest that the CEA promoter is an excellent candidate for directing E gene expression specifically toward colon cancer cells.

Attachment anxiety is related to Epstein-Barr virus latency.

Attachment theory provides a framework for understanding individual differences in chronic interpersonal stress. Attachment anxiety, a type of relationship insecurity characterized by worry about rejection and abandonment, is a chronic interpersonal stressor. Stress impacts cellular immunity, including herpesvirus reactivation. We investigated whether attachment anxiety was related to the expression of a latent herpesvirus, Epstein-Barr virus (EBV), when individuals were being tested for breast or colon cancer and approximately 1 year later. Participants (N=183) completed a standard attachment questionnaire and provided blood to assess EBV viral capsid antigen (VCA) IgG antibody titers. Individuals with more attachment anxiety had higher EBV VCA IgG antibody titers than those with less attachment anxiety. The strength of the association between attachment anxiety and antibody titers was the same at both assessments. This study is the first to show an association between latent herpesvirus reactivation and attachment anxiety. Because elevated herpesvirus antibody titers reflect poorer cellular immune system control over the latent virus, these data suggest that high attachment anxiety is associated with cellular immune dysregulation.

Carcinogenic viruses and solid cancers without sufficient evidence of causal association.

Viral infections are important risk factors for tumor development in humans. Selected types of cancers, either lymphomas or carcinomas, for which there is sufficient evidence in humans of a causal association with specific viruses, have been identified. Experimental and clinical data on the possible association of other tumor types and carcinogenic viruses are presently controversial. In this article, we review the current evidence on the relationship between breast, colorectal and lung cancers and carcinogenic viruses. The majority of the publications reviewed do not provide definitive evidence that the viruses studied are associated with breast, colon and lung cancers. However, since this association may be clinically relevant for some tumor subtypes (i.e., lung cancer and papillomaviruses), there is an urgent need for further investigation on this topic. Using innovative laboratory techniques for viral detection on well-defined tumor types, National and International networks against cancer should encourage and organize concerted research programs on viruses and solid cancer association.

NK-cell-dependent killing of colon carcinoma cells is mediated by natural cytotoxicity receptors (NCRs) and stimulated by parvovirus infection of target cells.

BACKGROUND: Investigating how the immune system functions during malignancies is crucial to developing novel therapeutic strategies. Natural killer (NK) cells, an important component of the innate immune system, play a vital role in immune defense against tumors and virus-infected cells. The poor survival rate in colon cancer makes it particularly important to develop novel therapeutic strategies. Oncolytic viruses, in addition to lysing tumor cells, may have the potential to augment antitumor immune responses. In the present study, we investigate the role of NK cells and how parvovirus H-1PV can modulate NK-cell mediated immune responses against colon carcinoma. METHODS: Human NK cells were isolated from the blood of healthy donors. The cytotoxicity and antibody-mediated inhibition of NK cells were measured in chromium release assays. Phenotypic assessment of colon cancer and dendritic cells was done by FACS. The statistical significance of the results was calculated with Student's t test (*p <0.05; **, p < 0.01; ***, p < 0.001). RESULTS: We show that IL-2-activated human NK cells can effectively kill colon carcinoma cells. Killing of colon carcinoma cells by NK cells was further enhanced upon infection of the former cells with parvovirus H-1PV. H-1PV has potent oncolytic activity against various tumors, yet its direct killing effect on colon carcinoma cells is limited. The cytotoxicity of NK cells towards colon carcinoma cells, both mock- and H-1PV-infected, was found to be mostly mediated by a combination of natural cytotoxicity receptors (NCRs), namely NKp30, 44, and 46. Colon carcinoma cells displayed low to moderate expression of NK cell ligands, and this expression was modulated upon H-1PV infection. Lysates of H-1PV-infected colon carcinoma cells were found to increase MHC class II expression on dendritic cells. CONCLUSIONS: Altogether, these data suggest that IL-2-activated NK cells actively kill colon carcinoma cells and that this killing is mediated by several natural cytotoxicity receptors (NCRs) in combination. Additionally, in association with parvovirus H-1PV, IL-2-activated NK cells have the potential to boost immune responses against colon cancer.

HHV-6 antigen and HHV-6 DNA expression in sporadic adenomatous polyps of the colon.

BACKGROUND. Human herpesvirus-6B (HHV-6B) antigens are commonly found in the intestinal mucosa of patients with immunosuppression. In a series of immunocompetent patients with adenomatous, polyp HHV-6B antigen expression from mucosal biopsies was more intense than in biopsies taken from patients receiving immunosuppressive drugs because of kidney transplantation or inflammatory bowel disease. METHODS. HHV-6B and cytomegalovirus (CMV) antigen expression was determined from mucosal biopsy samples by immunohistochemistry. HHV-6-DNA content was studied in adenomatous polyps (seven tubular adenomas and one tubulovillous adenoma) taken from eight immunocompetent patients and in three mucosal biopsy samples taken from immunocompetent patients without adenomas using in situ hybridization (ISH) method. RESULTS. HHV-6B antigen expression on mucosal biopsies was strongly positive in five of eight patients with adenomas and negative in all patients without adenoma. CMV antigen expression on mucosal biopsies was faintly positive in three of adenoma patients. HHV-6 ISH was positive in seven of eight adenomatous polyps, most intense in the tubulovillous adenoma and negative in all three mucosal biopsies of patients without adenomas. CONCLUSION. Intensive HHV-6-DNA expression was found in adenomatous polyps of the colon. Further studies on involvement of HHV-6 in the development of gastrointestinal polyps are warranted.