HCMV activates the IL-6-JAK-STAT3 axis in HepG2 cells and primary human hepatocytes

Targeting cytokine and chemokine signaling pathways for cancer therapy

Cytokines are critical in regulating immune responses and cellular behavior, playing dual roles in both normal physiology and the pathology of diseases such as cancer. These molecules, including interleukins, interferons, tumor necrosis factors, chemokines, and growth factors like TGF-β, VEGF, and EGF, can promote or inhibit tumor growth, influence the tumor microenvironment, and impact the efficacy of cancer treatments. Recent advances in targeting these pathways have shown promising therapeutic potential, offering new strategies to modulate the immune system, inhibit tumor progression, and overcome resistance to conventional therapies. In this review, we summarized the current understanding and therapeutic implications of targeting cytokine and chemokine signaling pathways in cancer. By exploring the roles of these molecules in tumor biology and the immune response, we highlighted the development of novel therapeutic agents aimed at modulating these pathways to combat cancer. The review elaborated on the dual nature of cytokines as both promoters and suppressors of tumorigenesis, depending on the context, and discussed the challenges and opportunities this presents for therapeutic intervention. We also examined the latest advancements in targeted therapies, including monoclonal antibodies, bispecific antibodies, receptor inhibitors, fusion proteins, engineered cytokine variants, and their impact on tumor growth, metastasis, and the tumor microenvironment. Additionally, we evaluated the potential of combining these targeted therapies with other treatment modalities to overcome resistance and improve patient outcomes. Besides, we also focused on the ongoing research and clinical trials that are pivotal in advancing our understanding and application of cytokine- and chemokine-targeted therapies for cancer patients.

Engineered HCMV-infected APCs enable the identification of new immunodominant HLA-restricted epitopes of anti-HCMV T-cell immunity

Complications due to HCMV infection or reactivation remain a challenging clinical problem in immunocompromised patients, mainly due to insufficient or absent T-cell functionality. Knowledge of viral targets is crucial to improve monitoring of high-risk patients and optimise antiviral T-cell therapy. To expand the epitope spectrum, genetically-engineered dendritic cells (DCs) and fibroblasts were designed to secrete soluble (s)HLA-A*11:01 and infected with an HCMV mutant lacking immune evasion molecules (US2-6 + 11). More than 700 HLA-A*11:01-restricted epitopes, including more than 50 epitopes derived from a broad range of HCMV open-reading-frames (ORFs) were identified by mass spectrometry and screened for HLA-A*11:01-binding using established prediction tools. The immunogenicity of the 24 highest scoring new candidates was evaluated in vitro in healthy HLA-A*11:01+/HCMV+ donors. Thus, four subdominant epitopes and one immunodominant epitope, derived from the anti-apoptotic protein UL36 and ORFL101C (A11SAL), were identified. Their HLA-A*11:01 complex stability was verified in vitro. In depth analyses revealed highly proliferative and cytotoxic memory T-cell responses against A11SAL, with T-cell responses comparable to the immunodominant HLA-A*02:01-restricted HCMVpp65NLV epitope. A11SAL-specific T cells were also detectable in vivo in immunosuppressed transplant patients and shown to be effective in an in vitro HCMV-infection model, suggesting their crucial role in inhibiting viral replication and improvement of patient's outcome. The developed in vitro pipeline is the first to utilise genetically-engineered DCs to identify naturally presented immunodominant HCMV-derived epitopes. It therefore offers advantages over in silico predictions, is transferable to other HLA alleles, and will significantly expand the repertoire of viral targets to improve therapeutic options.

Exploring the mechanism of Jianpi Huatan recipe in protecting hepatocellular carcinoma based on network pharmacology

ETHNOPHARMACOLOGICAL RELEVANCE

Jianpi Huatan Recipe (JPHTR) is an effective prescription for delaying progression of hepatocellular carcinoma (HCC) provided by Longhua Hospital affiliated to Shanghai University of traditional Chinese Medicine, and it is consisted of nine traditional Chinese drugs, but the protective mechanism of JPHTR against HCC progression is unclear.

AIM OF THE STUDY

To study the mechanism of JPHTR preventing the progression of HCC based on the network pharmacology.

MATERIALS AND METHODS

The chemical component and potential gene targets of JPHTR and the important gene targets of HCC were obtained by retrieving traditional Chinese medicine network pharmacology analysis system (TCMNPAS) database. The data obtained from the database are used to construct the drugs-chemical component-targets network and protein-protein interaction network by using Cytoscape software and STRING database. The potential targets of JPHTR and HCC targets were imported into TCMNPAS-related modules in order to obtain the Gene Ontology and Kyoto Encyclopedia of Genes and Genomes enrichment pathways. Finally, we used HCC rat model to verify the vital signaling pathways predicted by network pharmacology.

RESULTS

A total of 197 potential compounds and 721 potential targets of JPHTR and 611 important gene targets of HCC were obtained. Through the experiment in vivo, it was found that JPHTR can reduce the serum levels of alanine aminotransferase, aspartate aminotransferase and alkaline phosphatase, reduce the lipid droplets and inflammatory injury of liver tissue, and reduce the mRNA expression of Interleukin-6 (Il-6), Janus tyrosine Kinase2 (Jak2) and Forkhead box O3 (Foxo3) in FOXO pathway in the liver, thus delaying the development of HCC.

CONCLUSION

Through network pharmacology and rat experiments, it is preliminarily confirmed that JPHTR may delay the progression of HCC by regulating the expression of Il-6/Jak2/Foxo3 in FOXO signal pathway, which is expected to be a new therapeutic target for the protection of HCC.

Direct and biologically significant interactions of human herpesvirus 8 interferon regulatory factor 1 with STAT3 and Janus kinase TYK2

Human herpesvirus 8 (HHV-8) encodes four viral interferon regulatory factors (vIRFs) that target cellular IRFs and/or other innate-immune and stress signaling regulators and suppress the cellular response to viral infection and replication. For vIRF-1, cellular protein targets include IRFs, p53, p53-activating ATM kinase, BH3-only proteins, and antiviral signaling effectors MAVS and STING; vIRF-1 inhibits each, with demonstrated or likely promotion of HHV-8 de novo infection and productive replication. Here, we identify direct interactions of vIRF-1 with STAT3 and STAT-activating Janus kinase TYK2 (the latter reported previously by us to be inhibited by vIRF-1) and suppression by vIRF-1 of cytokine-induced STAT3 activation. Suppression of active, phosphorylated STAT3 (pSTAT3) by vIRF-1 was evident in transfected cells and vIRF-1 ablation in lytically-reactivated recombinant-HHV-8-infected cells led to increased levels of pSTAT3. Using a panel of vIRF-1 deletion variants, regions of vIRF-1 required for interactions with STAT3 and TYK2 were identified, which enabled correlation of STAT3 signaling inhibition by vIRF-1 with TYK2 binding, independently of STAT3 interaction. A viral mutant expressing vIRF-1 deletion-variant Δ198-222 refractory for TYK2 interaction and pSTAT3 suppression was severely compromised for productive replication. Conversely, expression of phosphatase-resistant, protractedly-active STAT3 led to impaired HHV-8 replication. Cells infected with HHV-8 mutants expressing STAT3-refractory vIRF-1 deletion variants or depleted of STAT3 displayed reduced vIRF-1 expression, while custom-peptide-promoted STAT3 interaction could effect increased vIRF-1 expression and enhanced virus replication. Taken together, our data identify vIRF-1 targeting and inhibition of TYK2 as a mechanism of STAT3-signaling suppression and critical for HHV-8 productive replication, the importance of specific pSTAT3 levels for replication, positive roles of STAT3 and vIRF-1-STAT3 interaction in vIRF-1 expression, and significant contributions to lytic replication of STAT3 targeting by vIRF-1.

Drug-induced liver injury following the use of tocilizumab or sarilumab in patients with coronavirus disease 2019

BACKGROUNDS

Interleukin-6 (IL-6) blockers including tocilizumab and sarilumab were approved by the U.S. Food and Drug Administration (FDA) in June 2021 for the treatment of patients with moderate to severe COVID-19. The use of sarilumab or tocilizumab in COVID-19 patients has been related to a reduction in mortality compared to standard care. Recent evidence has emerged concerning drug-induced liver injury (DILI) after sarilumab or tocilizumab applications in COVID-19 patients.

AIMS

The study aimed to estimate DILI associated with sarilumab or tocilizumab in treating moderate to severe patients infected with SARS-Cov-2.

METHODS

We conducted a retrospective pharmacovigilance study by data mining of the FDA's adverse event reporting systems (FAERS) database from the first quarter of 2004 to the fourth quarter of 2021 in confirmed COVID-19 patients. We analyzed DILI cases associated with tocilizumab or sarilumab in treating COVID-19 patients from the FAERS during this period. Disproportionality analysis and Bayesian analysis of COVID-19 patients were utilized for case analysis, and we also next compared the onset time and fatality rates of DILI following tocilizumab or sarilumab.

RESULTS

A total of 275 cases of TCZ or SAR-related DILI reports were extracted. A total of 192 AEs cases were related to tocilizumab (TCZ), and 83 were related to sarilumab (SAR). In patients treated with TCZ, most were < 75 years old (51.57%), with more male than female (46.35% vs. 13.02%). The correlation between IL-6 receptor antagonists and DILI was stronger in SAR (ROR = 12.94; 95%CI 9.6-17.44) than in TCZ (ROR = 1.33; 95%CI 1.14-1.55). The onset time of DILI was different between TCZ and SAR, and a significant difference was observed in TCZ than SAR (P < 0.0001). A significant difference was observed in the mortality rate of TCZ and SAR (P = 0.0009). DILI associated with COVID-19 patients treated with TCZ appeared to have earlier onset-time (1(0-46) day) VS. SAR (3.5(0-27) day).

CONCLUSION

This study shows strict monitor ought to be paid for TCZ or SAR when used for COVID-19 patients with poor liver function.

Prognosis of Human Cytomegalovirus in Cancer Patients Undergoing Chemotherapeutic Treatment in Egypt and an Emergent Prevalence of Glycoprotein B-5

The human cytomegalovirus (HCMV) is a global opportunistic β-herpes virus causing severe diseases in immune-compromised patients, such as malignant tumor patients, especially those undergoing chemotherapeutic treatment. This study aimed to determine the prevalence of HCMV-DNA in chemotherapeutic treatment naive cancer patients, and after chemotherapy, to compare between conventional nested PCR and ELISA techniques for the detection of HCMV, and to detect glycoprotein B genotypes. Plasma and serum samples before and after three chemotherapy cycles were collected from 49 chemotherapy-naive cancer patients. DNA was extracted from plasma samples using QIAamp® DNA Mini kit. HCMV-DNA was detected using a nested PCR technique. Multiplex nested PCR was used for HCMV-glycoprotein B (gB) genotyping. HCMV-IgG and -IgM were detected using ELISA technique. Thirty one (63.3 %) of the 49 plasma samples of the chemotherapy-naïve cancer patients were positive for HCMV-DNA; 21 of which remained positive after chemotherapy. However, 18 samples were negative of which 16 became positive after chemotherapy. gB-5 was the most common glycoprotein genotype detected (80.6 %), followed by gB-1, gB-3, gB-4, and gB-2. HCMV IgG was detected in the 49 serum samples of chemotherapy-naïve patients, and after exposure to chemotherapy. HCMV-DNA is commonly identified in cancer patients. Its detection after chemotherapy exposure may suggest HCMV reactivation. The most common genotype detected in cancer patients in Egypt is gB-5 in contrast to earlier research. IgG was detected in all patients. This indicates that HCMV is endemic in Egypt, necessitating the development of public awareness campaigns about HCMV infection and preventive strategies.

Hcmv-miR-UL148D regulates the staurosporine-induced apoptosis by targeting the Endoplasmic Reticulum to Nucleus signaling 1(ERN1)

The propensity of viruses to co-opt host cellular machinery by reprogramming the host’s RNA-interference machinery has been a major focus of research, however, regulation of host defense mechanisms by virus-encoded miRNA, is an additional regulatory realm gaining momentum in the arena of host-viral interactions. The Human Cytomegalovirus (HCMV) miRNAs, regulate many cellular pathways alone or in concordance with HCMV proteins, thereby paving a conducive environment for successful infection in the human host. We show that HCMV miRNA, hcmv-miR-UL148D inhibits staurosporine-induced apoptosis in HEK293T cells. We establish that ERN1 mRNA is a bonafide target of hcmv-miR-UL148D and its encoded protein IRE1α is translationally repressed by the overexpression of hcmv-miR-UL148D resulting in the attenuation of apoptosis. Unlike the host microRNA seed sequence (6–8 nucleotides), hcmv-miR-UL148D has long complementarity to 3’ UTR of ERN1 mRNA resulting in mRNA degradation. The repression of IRE1α by the hcmv-miR-UL148D further downregulates Xbp1 splicing and c-Jun N-terminal kinase phosphorylation thus regulating ER-stress and ER-stress induced apoptotic pathways. Strikingly, depletion of ERN1 attenuates staurosporine-induced apoptosis which further suggests that hcmv-miR-UL148D functions through regulation of its target ERN1. These results uncover a role for hcmv-miR-UL148D and its target ERN1 in regulating ER stress-induced apoptosis.

Mechanism of selenomethionine inhibiting of PDCoV replication in LLC-PK1 cells based on STAT3/miR-125b-5p-1/HK2 signaling

There are no licensed therapeutics or vaccines available against porcine delta coronavirus (PDCoV) to eliminate its potential for congenital disease. In the absence of effective treatments, it has led to significant economic losses in the swine industry worldwide. Similar to the current coronavirus disease 2019 (COVID-19) pandemic, PDCoV is trans-species transmissible and there is still a large desert for scientific exploration. We have reported that selenomethionine (SeMet) has potent antiviral activity against PDCoV. Here, we systematically investigated the endogenous immune mechanism of SeMet and found that STAT3/miR-125b-5p-1/HK2 signalling is essential for the exertion of SeMet anti-PDCoV replication function. Meanwhile, HK2, a key rate-limiting enzyme of the glycolytic pathway, was able to control PDCoV replication in LLC-PK1 cells, suggesting a strategy for viruses to evade innate immunity using glucose metabolism pathways. Overall, based on the ability of selenomethionine to control PDCoV infection and transmission, we provide a molecular basis for the development of new therapeutic approaches.

Polyploid giant cancer cells, EZH2 and Myc upregulation in mammary epithelial cells infected with high-risk human cytomegalovirus

Background

Human cytomegalovirus (HCMV) infection has been actively implicated in complex neoplastic processes. Beyond oncomodulation, the molecular mechanisms that might underlie HCMV-induced oncogenesis are being extensively studied. Polycomb repressive complex 2 (PRC2) proteins, in particular enhancer of zeste homolog 2 (EZH2) are associated with cancer progression. Nevertheless, little is known about EZH2 activation in the context of HCMV infection and breast oncogenesis.

Methods

Herein, we identified EZH2 as a downstream target for HCMV-induced Myc upregulation upon acute and chronic infection with high-risk strains using a human mammary epithelial model.

Findings

We detected polyploidy and CMV-transformed HMECs (CTH) cells harboring HCMV and dynamically undergoing the giant cells cycle. Acquisition of embryonic stemness markers positively correlated with EZH2 and Myc expression. EZH2 inhibitors curtail sustained CTH cells’ malignant phenotype. Besides harboring polyploid giant cancer cells (PGCCs), tumorigenic breast biopsies were characterized by an enhanced EZH2 and Myc expression, with a strong positive correlation between EZH2 and Myc expression, and between PGCC count and EZH2/Myc expression in the presence of HCMV. Further, we isolated two HCMV strains from EZH2^HighMyc^High basal-like tumors which replicate in MRC5 cells and transform HMECs toward CTH cells after acute infection.

Interpretation

Our data establish a potential link between HCMV-induced Myc activation, the subsequent EZH2 upregulation, and polyploidy induction. These data support the proposed tumorigenesis properties of EZH2/Myc, and allow the isolation of two oncogenic HCMV strains from EZH2^HighMyc^High basal breast tumors while identifying EZH2 as a potential therapeutic target in the management of breast cancer, particularly upon HCMV infection.

Funding

This work was supported by grants from the University of Franche-Comté (UFC) (CR3300), the Région Franche-Comté (2021-Y-08292 and 2021-Y-08290) and the Ligue contre le Cancer (CR3304) to Georges Herbein. Zeina Nehme is a recipient of a doctoral scholarship from the municipality of Habbouch. Sandy Haidar Ahmad is recipient of a doctoral scholarship from Lebanese municipality. Ranim El Baba is a recipient of a doctoral scholarship from Hariri foundation for sustainable human development.

Tumors and Cytomegalovirus: An Intimate Interplay

Human cytomegalovirus (HCMV) is a herpesvirus that alternates lytic and latent infection, infecting between 40 and 95% of the population worldwide, usually without symptoms. During its lytic cycle, HCMV can result in fever, asthenia, and, in some cases, can lead to severe symptoms such as hepatitis, pneumonitis, meningitis, retinitis, and severe cytomegalovirus disease, especially in immunocompromised individuals. Usually, the host immune response keeps the virus in a latent stage, although HCMV can reactivate in an inflammatory context, which could result in sequential lytic/latent viral cycles during the lifetime and thereby participate in the HCMV genomic diversity in humans and the high level of HCMV intrahost genomic variability. The oncomodulatory role of HCMV has been reported, where the virus will favor the development and spread of cancerous cells. Recently, an oncogenic role of HCMV has been highlighted in which the virus will directly transform primary cells and might therefore be defined as the eighth human oncovirus. In light of these new findings, it is critical to understand the role of the immune landscape, including the tumor microenvironment present in HCMV-harboring tumors. Finally, the oncomodulatory/oncogenic potential of HCMV could lead to the development of novel adapted therapeutic approaches against HCMV, especially since immunotherapy has revolutionized cancer therapeutic strategies and new therapeutic approaches are actively needed, particularly to fight tumors of poor prognosis.

Distinct Oncogenic Transcriptomes in Human Mammary Epithelial Cells Infected With Cytomegalovirus

Human cytomegalovirus is being recognized as a potential oncovirus beside its oncomodulation role. We previously isolated two clinical isolates, HCMV-DB (KT959235) and HCMV-BL (MW980585), which in primary human mammary epithelial cells promoted oncogenic molecular pathways, established anchorage-independent growth in vitro, and produced tumorigenicity in mice models, therefore named high-risk oncogenic strains. In contrast, other clinical HCMV strains such as HCMV-FS, KM, and SC did not trigger such traits, therefore named low-risk oncogenic strains. In this study, we compared high-risk oncogenic HCMV-DB and BL strains (high-risk) with low-risk oncogenic strains HCMV-FS, KM, and SC (low-risk) additionally to the prototypic HCMV-TB40/E, knowing that all strains infect HMECs in vitro. Numerous pro-oncogenic features including enhanced expression of oncogenes, cell survival, proliferation, and epithelial-mesenchymal transition genes were observed with HCMV-BL. In vitro, mammosphere formation was observed only in high-risk strains. HCMV-TB40/E showed an intermediate transcriptome landscape with limited mammosphere formation. Since we observed that Ki67 gene expression allows us to discriminate between high and low-risk HCMV strains in vitro, we further tested its expression in vivo. Among HCMV-positive breast cancer biopsies, we only detected high expression of the Ki67 gene in basal tumors which may correspond to the presence of high-risk HCMV strains within tumors. Altogether, the transcriptome of HMECs infected with HCMV clinical isolates displays an “oncogenic gradient” where high-risk strains specifically induce a prooncogenic environment which might participate in breast cancer development.

Viruses in colorectal cancer

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

Identification of UL69 Gene and Protein in Cytomegalovirus-Transformed Human Mammary Epithelial Cells

A growing body of evidence addressing the involvement of human cytomegalovirus (HCMV) in malignancies had directed attention to the oncomodulation paradigm. HCMV-DB infected human mammary epithelial cells (HMECs) in culture showed the emergence of clusters of rapidly proliferating, spheroid-shaped transformed cells named CTH (CMV-Transformed HMECs) cells. CTH cells assessment suggests a direct contribution of HCMV to oncogenesis, from key latent and lytic genes activating oncogenic pathways to fueling tumor evolution. We hypothesized that the presence of HCMV genome in CTH cells is of pivotal importance for determining its oncogenic potential. We previously reported the detection of a long non-coding (lnc) RNA4.9 gene in CTH cells. Therefore, we assessed here the presence of UL69 gene, located nearby and downstream of the lncRNA4.9 gene, in CTH cells. The HCMV UL69 gene in CTH cells was detected using polymerase chain reaction (PCR) and sequencing of UL69 gene was performed using Sanger method. The corresponding amino acid sequence was then blasted against the UL69 sequence derived from HCMV-DB genome using NCBI Protein BLAST tool. A 99% identity was present between the nucleotide sequence present in CTH cells and HCMV-DB genome. UL69 transcript was detected in RNA extracts of CTH cells, using a reverse transcription polymerase chain reaction (RT-PCR) assay, and pUL69 protein was identified in CTH lysates using western blotting. Ganciclovir-treated CTH cells showed a decrease in UL69 gene detection and cellular proliferation. In CTH cells, the knockdown of UL69 with siRNA was assessed by RT-qPCR and western blot to reveal the impact of pUL69 on HCMV replication and CTH cell proliferation. Finally, UL69 gene was detected in breast cancer biopsies. Our results indicate a close link between the UL69 gene detected in the HCMV-DB isolate used to infect HMECs, and the UL69 gene present in transformed CTH cells and tumor biopsies, further highlighting a direct role for HCMV in breast tumor development.

Apoptosis Disorder, a Key Pathogenesis of HCMV-Related Diseases

Human cytomegalovirus (HCMV) belongs to the β-herpesvirus family, which is transmitted in almost every part of the world and is carried by more than 90% of the general population. Increasing evidence indicates that HCMV infection triggers numerous diseases by disrupting the normal physiological activity of host cells, particularly apoptosis. Apoptosis disorder plays a key role in the initiation and development of multiple diseases. However, the relationship and molecular mechanism of HCMV-related diseases and apoptosis have not yet been systematically summarized. This review aims to summarize the role of apoptosis in HCMV-related diseases and provide an insight into the molecular mechanism of apoptosis induced by HCMV infection. We summarize the literature on HCMV-related diseases and suggest novel strategies for HCMV treatment by regulating apoptosis.

Polyploid giant cancer cells, stemness and epithelial-mesenchymal plasticity elicited by human cytomegalovirus

A growing body of evidence is recognizing human cytomegalovirus (HCMV) as a potential oncogenic virus. We hereby provide the first experimental in vitro evidence for HCMV as a reprogramming vector, through the induction of dedifferentiation of mature human mammary epithelial cells (HMECs), generation of a polyploid giant cancer cell (PGCC) phenotype characterized by sustained growth of blastomere-like cells, in concordance with the acquisition of embryonic stem cells characteristics and epithelial-mesenchymal plasticity. HCMV presence parallels the succession of the observed cellular and molecular events potentially ensuing the transformation process. Correlation between PGCCs detection and HCMV presence in breast cancer tissue further validates our hypothesis in vivo. Our study indicates that some clinical HCMV strains conserve the potential to transform HMECs and fit with a "blastomere-like" model of oncogenesis, which may be relevant in the pathophysiology of breast cancer and other adenocarcinoma, especially of poor prognosis.

Viral growth factor- and STAT3 signaling-dependent elevation of the TCA cycle intermediate levels during vaccinia virus infection

Metabolism is a crucial frontier of host-virus interaction as viruses rely on their host cells to provide nutrients and energy for propagation. Vaccinia virus (VACV) is the prototype poxvirus. It makes intensive demands for energy and macromolecules in order to build hundreds and thousands of viral particles in a single cell within hours of infection. Our comprehensive metabolic profiling reveals profound reprogramming of cellular metabolism by VACV infection, including increased levels of the intermediates of the tri-carboxylic acid (TCA) cycle independent of glutaminolysis. By investigating the level of citrate, the first metabolite of the TCA cycle, we demonstrate that the elevation of citrate depends on VACV-encoded viral growth factor (VGF), a viral homolog of cellular epidermal growth factor. Further, the upregulation of citrate is dependent on STAT3 signaling, which is activated non-canonically at the serine727 upon VACV infection. The STAT3 activation is dependent on VGF, and VGF-dependent EGFR and MAPK signaling. Together, our study reveals a novel mechanism by which VACV manipulates cellular metabolism through a specific viral factor and by selectively activating a series of cellular signaling pathways.

Vaccinia virus (VACV) is a large DNA virus with an acute and increasing demand for energy and macromolecules to build hundreds and thousands of viral particles in a single cell within hours of infection. The demand postulates reprogramming of the TCA cycle, as it is the central metabolic hub of a cell that generates metabolites for energy production and macromolecule synthesis. We show that VACV infection reprograms cellular metabolism globally, elevating the TCA cycle intermediate levels and modulating related cell metabolism. The elevation of the TCA cycle intermediates depends on the virus-encoded growth factor that stimulates non-canonical STAT3 signaling during VACV infection. Our results provide the metabolic foundation of viral growth factor to boost VACV infection.

HSATII RNA is induced via a noncanonical ATM-regulated DNA damage response pathway and promotes tumor cell proliferation and movement

Pericentromeric human satellite II (HSATII) repeats are normally silent but can be actively transcribed in tumor cells, where increased HSATII copy number is associated with a poor prognosis in colon cancer, and in human cytomegalovirus (HCMV)-infected fibroblasts, where the RNA facilitates viral replication. Here, we report that HCMV infection or treatment of ARPE-19 diploid epithelial cells with DNA-damaging agents, etoposide or zeocin, induces HSATII RNA expression, and a kinase-independent function of ATM is required for the induction. Additionally, various breast cancer cell lines growing in adherent, two-dimensional cell culture express HSATII RNA at different levels, and levels are markedly increased when cells are infected with HCMV or treated with zeocin. High levels of HSATII RNA expression correlate with enhanced migration of breast cancer cells, and knockdown of HSATII RNA reduces cell migration and the rate of cell proliferation. Our investigation links high expression of HSATII RNA to the DNA damage response, centered on a noncanonical function of ATM, and demonstrates a role for the satellite RNA in tumor cell proliferation and movement.

Human cytomegalovirus protein UL136 activates the IL-6/STAT3 signal through MiR-138 and MiR-34c in gastric cancer cells

BACKGROUND

Accumulating evidences have indicated that human cytomegalovirus (HCMV) may link to multiple human malignancies, including gastric cancer. However, the mechanistic role of HCMV in GC remains largely unknown.

METHODS

In this study, we have successfully established HCMV latent gene UL-136-expressing gastric cancer cells. We measured cell proliferation of GC cells, MNK-45 and SGC-7901, with stable UL136 expression or paired control cells by using CCK-8 assay. We have showed that GC cells with stable UL136 expression had a rapid cell growth. Furthermore, our data from matrigel-coated transwell assay have demonstrated that UL136 expressing GC cells showed an enhanced invasion capacity compared to control cells. Furthermore, ectopic expression of UL136 inhibits tumorigenicity in an animal model.

RESULTS

We observed that IL-6/STAT3 was stimulated by UL136 overexpression. Also, miR-138 is consistently up-regulated, while miR-34 down-regulated by UL136 in either MNK-45 or SGC-7901 cells. Our mechanistic study showed that treatment of miR-138 mimics in MNK-45 cells indeed inhibited SIRT1 expression to increase phosphorylation level of STAT3. MiR-34c suppressed expression of IL6R through direct binding with the putative 3'UTR binding sites of this gene. UL136 regulate IL6/STAT3 pathway, at least in part, through down-regulation of miR-34c in GC cells.

CONCLUSION

In conclusion, HCMV-induced miR-34c or miR-138 involves in the activation of IL6/STAT3 signaling. Targeting the IL6-STAT3 axis or miRNAs represent a promising strategy for HCMV-related tumor formation.

The Dynamic Interface of Viruses with STATs

Viruses commonly antagonize the antiviral type I interferon response by targeting signal transducer and activator of transcription 1 (STAT1) and STAT2, key mediators of interferon signaling. Other STAT family members mediate signaling by diverse cytokines important to infection, but their relationship with viruses is more complex. Importantly, virus-STAT interaction can be antagonistic or stimulatory depending on diverse viral and cellular factors. While STAT antagonism can suppress immune pathways, many viruses promote activation of specific STATs to support viral gene expression and/or produce cellular conditions conducive to infection. It is also becoming increasingly clear that viruses can hijack noncanonical STAT functions to benefit infection. For a number of viruses, STAT function is dynamically modulated through infection as requirements for replication change. Given the critical role of STATs in infection by diverse viruses, the virus-STAT interface is an attractive target for the development of antivirals and live-attenuated viral vaccines. Here, we review current understanding of the complex and dynamic virus-STAT interface and discuss how this relationship might be harnessed for medical applications.

Tumor Control by Cytomegalovirus: A Door Open for Oncolytic Virotherapy?

Belonging to the herpesviridae family, human cytomegalovirus (HCMV) is a well-known ubiquitous pathogen that establishes a lifelong infection in humans. Recently, a beneficial tumor-cytoreductive role of CMV infection has been defined in human and animal models. Described as a potential anti-tumoral activity, HCMV modulates the tumor microenvironment mainly by inducing cell death through apoptosis and prompting a robust stimulatory effect on the immune cells infiltrating the tumor tissue. However, major current limitations embrace transient protective effect and a viral dissemination potential in immunosuppressed hosts. The latter could be counteracted through direct viral intratumoral delivery, use of non-human strains, or even defective CMV vectors to ascertain transformed cells-selective tropism. This potential oncolytic activity could be complemented by tackling further platforms, namely combination with immune checkpoint inhibitors or epigenetic therapy, as well as the use of second-generation chimeric oncovirus, for instance HCMV/HSV-1 oncolytic virus. Overall, preliminary data support the use of CMV in viral oncolytic therapy as a viable option, establishing thus a potential new modality, where further assessment through extensive basic research armed by molecular biotechnology is compulsory.

Overexpression of the human cytomegalovirus UL111A is correlated with favorable survival of patients with gastric cancer and changes T-cell infiltration and suppresses carcinogenesis

Purpose

We previously found that human cytomegalovirus (HCMV) infection is associated with gastric cancer (GC) development. UL111A plays a role during HCMV productive or latent infection. However, UL111A expression profiles in GC tissues and their relationship with this disease are unknown.

Methods

PCR and nested RT-PCR were performed to verify UL111A expression in 71 GC tissues and its transcripts in 16 UL111A-positive GC samples. UL111A expression levels in GC patients were evaluated by immunohistochemistry on a tissue microarray for 620 GC patients. The correlations among UL111A expression levels, clinicopathological characteristics, and prognosis were analyzed. Further, the effects of overexpression of latency-associated viral interleukin-10 (LAcmvIL-10) and cmvIL-10 on GC cell proliferation, colony formation, migration, and invasion were assessed.

Results

The UL111A detection rate in GC tissues was 32.4% (23/71) and that of its mRNA expression was 68.75% (11/16). High expression of UL111A was also related to better overall and disease-free survival in GC patients. GC patients with TNM II/III stage expressing higher UL111A levels might benefit from adjuvant chemotherapy (ACT) after surgery. Moreover, high UL111A expression was also associated with increased CD4+ , CD8+ T-lymphocyte and Foxp3+ T-cell infiltration. In vitro assays further demonstrated that LAcmvIL-10 and cmvIL-10 overexpression inhibits GC cell line proliferation, colony formation, migration, and invasion.

Conclusions

High UL111A expression changes the number of infiltrating T cells and is associated with favorable survival. Therefore, UL111A could be used as an independent prognostic biomarker and might be a potential therapeutic target for GC.

Electronic supplementary material

The online version of this article (10.1007/s00432-019-03092-x) contains supplementary material, which is available to authorized users.

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

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

Accelerated cancer aggressiveness by viral oncomodulation: New targets and newer natural treatments for cancer control and treatment

An infectious etiology for a number of cancers has been entertained for over 100 years and modern studies have confirmed that a number of viruses are linked to cancer induction. While a large number of viruses have been demonstrated in a number of types of cancers, most such findings have been dismissed in the past as opportunistic infections, especially with persistent viruses with high rates of infectivity of the world’s populations. More recent studies have clearly shown that while not definitely causing these cancers, these viruses appear capable of affecting the biology of these tumors in such a way as to make them more aggressive and more resistant to conventional treatments. The term oncomodulatory viruses has been used to describe this phenomenon. A number of recent studies have shown a growing number of ways these oncomodulatory viruses can alter the pathology of these tumors by affecting cell-signaling, cell metabolism, apoptosis mechanisms, cell-cell communication, inflammation, antitumor immunity suppression, and angiogenesis. We are also learning that much of the behavior of tumors depends on cancer stem cells and stromal cells within the tumor microenvironment, which participate in extensive, dynamic crosstalk known to affect tumor behavior. Cancer stem cells have been found to be particularly susceptible to infection by human cytomegalovirus. In a number of studies, it has been shown that while only a select number of cells are actually infected with the virus, numerous viral proteins are released into cancer and stromal cells in the microenvironment and these viral proteins are known to affect tumor behavior and aggressiveness.

Murine Cytomegalovirus Infection of Melanoma Lesions Delays Tumor Growth by Recruiting and Repolarizing Monocytic Phagocytes in the Tumor

Cytomegalovirus (CMV) is a ubiquitous betaherpesvirus that infects many different cell types. Human CMV (HCMV) has been found in several solid tumors, and it has been hypothesized that it may promote cellular transformation or exacerbate tumor growth. Paradoxically, in some experimental situations, murine CMV (MCMV) infection delays tumor growth. We previously showed that wild-type MCMV delayed the growth of poorly immunogenic B16 melanomas via an undefined mechanism. Here, we show that MCMV delayed the growth of these immunologically "cold" tumors by recruiting and modulating tumor-associated macrophages. Depletion of monocytic phagocytes with clodronate completely prevented MCMV from delaying tumor growth. Mechanistically, our data suggest that MCMV recruits new macrophages to the tumor via the virus-encoded chemokine MCK2, and viruses lacking this chemokine were unable to delay tumor growth. Moreover, MCMV infection of macrophages drove them toward a proinflammatory (M1)-like state. Importantly, adaptive immune responses were also necessary for MCMV to delay tumor growth as the effect was substantially blunted in Rag-deficient animals. However, viral spread was not needed and a spread-defective MCMV strain was equally effective. In most mice, the antitumor effect of MCMV was transient. Although the recruited macrophages persisted, tumor regrowth correlated with a loss of viral activity in the tumor. However, an additional round of MCMV infection further delayed tumor growth, suggesting that tumor growth delay was dependent on active viral infection. Together, our results suggest that MCMV infection delayed the growth of an immunologically cold tumor by recruiting and modulating macrophages in order to promote anti-tumor immune responses.IMPORTANCE Cytomegalovirus (CMV) is an exciting new platform for vaccines and cancer therapy. Although CMV may delay tumor growth in some settings, there is also evidence that CMV may promote cancer development and progression. Thus, defining the impact of CMV on tumors is critical. Using a mouse model of melanoma, we previously found that murine CMV (MCMV) delayed tumor growth and activated tumor-specific immunity although the mechanism was unclear. We now show that MCMV delayed tumor growth through a mechanism that required monocytic phagocytes and a viral chemokine that recruited macrophages to the tumor. Furthermore, MCMV infection altered the functional state of macrophages. Although the effects of MCMV on tumor growth were transient, we found that repeated MCMV injections sustained the antitumor effect, suggesting that active viral infection was needed. Thus, MCMV altered tumor growth by actively recruiting macrophages to the tumor, where they were modulated to promote antitumor immunity.

Pentagalloylglucose Inhibits the Replication of Rabies Virus via Mediation of the miR-455/SOCS3/STAT3/IL-6 Pathway

Our previous study showed that pentagalloylglucose (PGG), a naturally occurring hydrolyzable phenolic tannin, possesses significant anti-rabies virus (RABV) activity. In BHK-21 cells, RABV induced the overactivation of signal transducer and activator of transcription 3 (STAT3) by suppressing the expression of suppressor of cytokine signaling 3 (SOCS3). Inhibition of STAT3 by niclosamide, small interfering RNA, or exogenous expression of SOCS3 all significantly suppressed the replication of RABV. Additionally, RABV-induced upregulation of microRNA 455-5p (miR-455-5p) downregulated SOCS3 by directly binding to the 3' untranslated region (UTR) of SOCS3. Importantly, PGG effectively reversed the expression of miR-455-5p and its following SOCS3/STAT3 signaling pathway. Finally, activated STAT3 elicited the expression of interleukin-6 (IL-6), thereby contributing to RABV-associated encephalomyelitis; however, PGG restored the level of IL-6 in vitro and in vivo in a SOCS3/STAT3-dependent manner. Altogether, these data identify a new miR-455-5p/SOCS3/STAT3 signaling pathway that contributes to viral replication and IL-6 production in RABV-infected cells, with PGG exerting its antiviral effect by inhibiting the production of miR-455-5p and the activation of STAT3.IMPORTANCE Rabies virus causes lethal encephalitis in mammals and poses a serious public health threat in many parts of the world. Numerous strategies have been explored to combat rabies; however, their efficacy has always been unsatisfactory. We previously reported a new drug, PGG, which possesses a potent inhibitory activity on RABV replication. Herein, we describe the underlying mechanisms by which PGG exerts its anti-RABV activity. Our results show that RABV induces overactivation of STAT3 in BHK-21 cells, which facilitates viral replication. Importantly, PGG effectively inhibits the activity of STAT3 by disrupting the expression of miR-455-5p and increases the level of SOCS3 by directly targeting the 3' UTR of SOCS3. Furthermore, the downregulated STAT3 inhibits the production of IL-6, thereby contributing to a reduction in the inflammatory response in vivo Our study indicates that PGG effectively inhibits the replication of RABV by the miR-455-5p/SOCS3/STAT3/IL-6-dependent pathway.

Identification of adipocyte plasma membrane-associated protein as a novel modulator of human cytomegalovirus infection

Human cytomegalovirus (HCMV) is a ubiquitous pathogen that can cause disability in newborns and serious clinical diseases in immunocompromised patients. HCMV has a large genome with enormous coding potential; its viral particles are equipped with complicated glycoprotein complexes and can infect a wide range of human cells. Although multiple host cellular receptors interacting with viral glycoproteins have been reported, the mechanism of HCMV infection remains a mystery. Here we report identification of adipocyte plasma membrane-associated protein (APMAP) as a novel modulator active in the early stage of HCMV infection. APMAP is necessary for HCMV infection in both epithelial cells and fibroblasts; knockdown of APMAP expression significantly reduced HCMV infection of these cells. Interestingly, ectopic expression of human APMAP in cells refractory to HCMV infection, such as canine MDCK and murine NIH/3T3 cells, promoted HCMV infection. Furthermore, reduction in viral immediate early (IE) gene transcription at 6 h post infection and delayed nucleus translocation of tegument delivered pp65 at 4 h post infection were detected in APMAP-deficient cells but not in the wildtype cells. These results suggest that APMAP plays a role in the early stage of HCMV infection. Results from biochemical studies of APMAP and HCMV proteins suggest that APMAP could participate in HCMV infection through interaction with gH/gL containing glycoprotein complexes at low pH and mediate nucleus translocation of tegument pp65. Taken together, our results suggest that APMAP functions as a modulator promoting HCMV infection in multiple cell types and is an important player in the complex HCMV infection mechanism.

The emerging role of human cytomegalovirus infection in human carcinogenesis: a review of current evidence and potential therapeutic implications

It is well-established that infections with viruses harboring oncogenic potential increase the cancer risk. Virus induced oncogenic processes are influenced by a complex and unique combination of host and environmental risk factors that are currently not fully understood. Many of the oncogenic viruses exhibit a prolonged, asymptomatic latency after a primary infection, and cause cancer in only a minority of carriers. From an epidemiologic point of view, it is therefore difficult to determine their role in cancer development. However, recent evidence suggests a neoplastic potential of one additional ubiquitous virus; human Cytomegalovirus (HCMV). Emerging data presents HCMV as a plausible cancer-causing virus by demonstrating its presence in >90% of common tumor types, while being absent in normal tissue surrounding the tumor. HCMV targets many cell types in tumor tissues, and can cause all the ten proposed hallmarks of cancer. This virus exhibits cellular tumor-promoting and immune-evasive strategies, hijacks proangiogenic and anti-apoptotic mechanisms and induces immunosuppressive effects in the tumor micro-environment. Recognizing new cancer-causing mechanisms may increase the therapeutic potential and prophylactic options for virus associated cancer forms. Such approaches could limit viral spread, and promote anti-viral and immune controlling strategies if given as add on to standard therapy to potentially improve the prognosis of cancer patients. This review will focus on HCMV-related onco-viral mechanisms and the potential of HCMV as a new therapeutic target in HCMV positive cancer forms.

Effect of haptoglobin on the treatment of chronic hepatitis B with interferon

There are two main types of drugs that are used to treat chronic hepatitis B (CHB), including interferon (IFN) and nucleotide analogues. IFN inhibits the virus through direct antiviral activity and via immune regulation, and it has been widely applied for the treatment of CHB and other infections. However, the efficiency of IFN therapy is not entirely satisfactory. The aim of the present study was to investigate the factors affecting IFN therapy. The plasma of patients with CHB treated with IFN was collected and divided into the virological response group and non-virological response group according to their virological response. Serum proteins of virologically responsive patients were compared before and after IFN therapy using isobaric tags for relative and absolute quantitation technology. ELISA was used to validate these results in the same sample. In in vitro cell experiments, HepG2.2.15 cells were transfected with haptoglobin (Hp)-targeting small interfering RNA to inhibit expression of the Hp protein, and reverse transcription-quantitative polymerase chain reaction and western blotting were utilized to detect hepatitis B virus (HBV)-DNA, IFN and downstream molecular changes in the cell supernatants. The Hp protein levels were demonstrated to be significantly lower following 48 weeks of IFN therapy, and the levels of Hp in patients in the virological response group were significantly lower than those in the non-virological response group. In in vitro cell experiments, following inhibition of Hp protein expression, significantly decreased levels of HBV-DNA, and elevated levels of IFN and its downstream molecules were observed. These findings suggest that Hp may be able to predict the efficacy of IFN therapy, and it may inhibit HBV clearance. There is an association between Hp and IFN, which requires further clinical and laboratory studies to explore.

Impact of Cytomegalovirus Infection on the Outcome of Patients With Cirrhosis: A Preliminary Study

GOALS

The aims of this study were to evaluate whether cytomegalovirus (CMV) infection is associated with hepatocellular carcinoma (HCC) and liver-related mortality in cirrhotic patients.

BACKGROUND

In cirrhotic patients, the determinants of HCC and liver-related death are imperfectly known. CMV infection, by its prooncogenic and proinflammatory properties, may favor both the development of HCC and deleterious systemic inflammation.

STUDY

In the 1178 patients included between June 2008 and December 2012 in the CIrrhose et Risque de Carcinome Hépatocellulaire dans le grand-Est (CIRCE) study, a French multicenter case-control study designed to identify risk factors of HCC among cirrhotic patients, we identified 432 patients with interpretable CMV serological status at baseline. They included 159 cases with HCC and 273 controls. We measured factors associated with HCC at baseline and subsequent HCC in controls, and predictors of overall and liver-related death in the whole study population.

RESULTS

During a median follow-up of 31 months, 25 cases of HCC developed in controls, and 209 deaths (163 liver-related) were recorded. There were 247 (57.2%) CMV-seropositive patients. CMV seropositivity was not associated with more frequent HCC at baseline or during follow-up, but among CMV-positive patients with HCC, the proportion of multinodular, infiltrative, or metastatic tumors at diagnosis was higher (73.8% vs. 57.3%; P=0.029), inducing higher mortality (74% vs. 52% at 3 years; P=0.004). By Cox-regression adjusted for age, gender, Model for End-stage Liver Disease (MELD) score, HCC at baseline, and diabetes, CMV seropositivity independently predicted all-cause (hazard ratio=1.45; 95% confidence interval, 1.08-1.94; P=0.013) and liver-related mortality (hazard ratio=1.56; 95% confidence interval, 1.04-2.30; P=0.031).

CONCLUSIONS

In this preliminary study, CMV-seropositive cirrhotic patients were at higher risk of liver-related death caused by more aggressive HCCs or severe cirrhosis complications. These findings warrant confirmation.

Enhanced anticancer effect of oncostatin M combined with salinomycin in CD133+ HepG2 liver cancer cells

Oncostatin M (OSM) induces the differentiation of liver cancer stem cells (LCSCs) and increases sensitivity to the chemotherapeutic agent 5-fluorouracil, whereas salinomycin (Sal) induces apoptosis in cancer stem cells and inhibits the proliferation of liver cancer cells. However, there have been no studies investigating the anticancer effects of combination treatment with OSM and Sal. In the present study, we investigated the synergistic effects of OSM and Sal on LCSCs, the CD133⁺ subpopulations from HepG2 human liver cancer cells. CD133⁺ LCSCs were isolated using an immunomagnetic bead technique and identified through colony formation. After incubating with OSM and Sal, the ability of LCSC proliferation and invasion, as well as apoptosis rates were evaluated, and the expression of stemness-related genes was examined by quantitative real-time polymerase chain reaction. Additionally, the secretion of α-fetoprotein (AFP) and albumin (ALB) were analyzed by enzyme-linked immunosorbent assay. Our results indicated that OSM combined with Sal significantly suppressed LCSC proliferation and invasion and induced apoptosis, as determined by flow cytometry and increases in cleaved caspase-3 levels detected by western blotting. The results of the JC-1 staining assay indicated that this effect involved the mitochondrial pathway. Moreover, combination treatment reduced the expression of CD133 in LCSCs and suppressed stemness-related gene expression. Furthermore, the LCSCs produced lower levels of AFP and higher levels of ALB following combination treatment. In all experiments, combination treatment elicited more efficient anticancer effects on LCSCs as compared with single-drug treatment; therefore, our results demonstrated that combined treatment with OSM and Sal inhibited proliferation and induced differentiation and apoptosis in LCSCs, suggesting combined use of OSM and Sal as a therapeutic strategy for liver cancer.

The transcriptome of human mammary epithelial cells infected with the HCMV-DB strain displays oncogenic traits

Increasing evidence indicates that human cytomegalovirus (HCMV) populations under the influence of host environment, can either be stable or rapidly differentiating, leading to tissue compartment colonization. We isolated previously from a 30-years old pregnant woman, a clinical isolate of HCMV, that we refered to as the HCMV-DB strain (accession number KT959235). The HCMV-DB clinical isolate demonstrated its ability to infect primary macrophages and to upregulate the proto-oncogene Bcl-3. We observed in this study that the genome of HCMV-DB strain is close to the genomes of other primary clinical isolates including the Toledo and the JP strains with the later having been isolated from a glandular tissue, the prostate. Using a phylogenetic analysis to compare the genes involved in virus entry, we observed that the HCMV-DB strain is close to the HCMV strain Merlin, the prototype HCMV strain. HCMV-DB infects human mammary epithelial cells (HMECs) which in turn display a ER−/PR−/HER2− phenotype, commonly refered to as triple negative. The transcriptome of HCMV-DB-infected HMECs presents the characteristics of a pro-oncogenic cellular environment with upregulated expression of numerous oncogenes, enhanced activation of pro-survival genes, and upregulated markers of cell proliferation, stemcellness and epithelial mesenchymal transition (EMT) that was confirmed by enhanced cellular proliferation and tumorsphere formation in vitro. Taken together our data indicate that some clinical isolates could be well adapted to the mammary tissue environment, as it is the case for the HCMV-DB strain. This could influence the viral fitness, ultimately leading to breast cancer development.

The Human Cytomegalovirus, from Oncomodulation to Oncogenesis

Besides its well-described impact in immunosuppressed patients, the role of human cytomegalovirus (HCMV) in the pathogenesis of cancer has been more recently investigated. In cancer, HCMV could favor the progression and the spread of the tumor, a paradigm named oncomodulation. Although oncomodulation could account for part of the protumoral effect of HCMV, it might not explain the whole impact of HCMV infection on the tumor and the tumoral microenvironment. On the contrary cases have been reported where HCMV infection slows down the progression and the spread of the tumor. In addition, HCMV proteins have oncogenic properties per se, HCMV activates pro-oncogenic pathways in infected cells, and recently the direct transformation of cells following HCMV infection has been described, which gave rise to tumors when injected in mice. Thus, beyond the oncomodulation model, this review will assess the direct transforming role of HMCV-infected cells and the potential classification of HCMV as an oncovirus.

STAT3 roles in viral infection: antiviral or proviral?

Signal transducer and activator of transcription 3 (STAT3) is a transcription factor which can be activated by cytokines, growth factor receptors, and nonreceptor-like tyrosine kinase. An activated STAT3 translocates into the nucleus and combines with DNA to regulate the expression of target genes involved in cell proliferation, differentiation, apoptosis and metastasis. Recent studies have shown that STAT3 plays important roles in viral infection and pathogenesis. STAT3 exhibits a proviral function in several viral infections, including those of HBV, HCV, HSV-1, varicella zoster virus, human CMV and measles virus. However, in some circumstances, STAT3 has an antiviral function in other viral infections, such as enterovirus 71, severe acute respiratory syndrome coronavirus and human metapneumovirus. This review summarizes the roles of STAT3 in viral infection and pathogenesis, and briefly discusses the molecular mechanisms involved in these processes.

The Human Cytomegalovirus Strain DB Activates Oncogenic Pathways in Mammary Epithelial Cells

Background

Human cytomegalovirus (HCMV) establishes a persistent life-long infection and increasing evidence indicates HCMV infection can modulate signaling pathways associated with oncogenesis. Breast milk is an important route of HCMV transmission in humans and we hypothesized that mammary epithelial cells could be one of the main cellular targets of HCMV infection.

Methods

The infectivity of primary human mammary epithelial cells (HMECs) was assessed following infection with the HCMV-DB strain, a clinical isolate with a marked macrophage-tropism. The impact of HCMV-DB infection on expression of p53 and retinoblastoma proteins, telomerase activity and oncogenic pathways (c-Myc, Akt, Ras, STAT3) was studied. Finally the transformation of HCMV-DB infected HMECs was evaluated using soft agar assay. CTH cells (CMV Transformed HMECs) were detected in prolonged cultures of infected HMECs. Tumor formation was observed in NOD/SCID Gamma (NSG) mice injected with CTH cells. Detection of long non coding RNA4.9 (lncRNA4.9) gene was assessed in CTH cells, tumors isolated from xenografted NSG mice and biopsies of patients with breast cancer using qualitative and quantitative PCR.

Results

We found that HCMV, especially a clinical strain named HCMV-DB, infects HMECs in vitro. The clinical strain HCMV-DB replicates productively in HMECs as evidenced by detection of early and late viral transcripts and proteins. Following infection of HMECs with HCMV-DB, we observed the inactivation of retinoblastoma and p53 proteins, the activation of telomerase activity, the activation of the proto-oncogenes c-Myc and Ras, the activation of Akt and STAT3, and the upregulation of cyclin D1 and Ki67 antigen. Colony formation was observed in soft agar seeded with HCMV-DB-infected HMECs. Prolonged culture of infected HMECs resulted in the development of clusters of spheroid cells that we called CTH cells (CMV Transformed HMECs). CTH cells when injected in NOD/SCID Gamma (NSG) mice resulted in the development of tumors. We detected in CTH cells the presence of a HCMV signature corresponding to a sequence of the long noncoding RNA4.9 (lncRNA4.9) gene. We also found the presence of the HCMV lncRNA4.9 sequence in tumors isolated from xenografted NSG mice injected with CTH cells and in biopsies of patients with breast cancer using qualitative and quantitative PCR.

Conclusions

Our data indicate that key molecular pathways involved in oncogenesis are activated in HCMV-DB-infected HMECs that ultimately results in the transformation of HMECs in vitro with the appearance of CMV-transformed HMECs (CTH cells) in culture. CTH cells display a HCMV signature corresponding to a lncRNA4.9 genomic sequence and give rise to fast growing triple-negative tumors in NSG mice. A similar lncRNA4.9 genomic sequence was detected in tumor biopsies of patients with breast cancer.

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The infection of primary human mammary epithelial cells (HMECs) with the HCMV-DB strain results in a pro-oncogenic cellular environment.

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HCMV-DB transforms primary HMECs in vitro as measured by a soft agar assay.

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Prolonged culture of HMECs infected with HCMV-DB results in the appearance of clusters of spheroid cells that we called CTH cells (CMV Transformed HMECs).

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CTH cells when injected in NOD/SCID Gamma mice resulted in the development of breast tumor.

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The HCMV lncRNA4.9 sequence was detected in CTH cells, in tumors isolated from xenografted NSG mice injected with CTH cells and in biopsies of patients with breast cancer.

Research in Context: Worldwide breast cancer is the most common cancer diagnosed among women. Etiological factors involved in breast cancer include genetic and environmental risk factors and among these latter viruses could be involved with close to one-fifth of all cancers in the world caused by infectious agents. We found that the cytomegalovirus strain DB, a member of the herpesvirus family, activates oncogenic pathways in infected mammary epithelial cells, transforms these cells in culture and favors the appearance of tumors in xenografted mice. Our findings might lead to a better understanding of the pathogenesis of breast cancer.

Viral manipulation of STAT3: Evade, exploit, and injure

Signal transducer and activator of transcription 3 (STAT3) is a key regulator of numerous physiological functions, including the immune response. As pathogens elicit an acute phase response with concerted activation of STAT3, they are confronted with two evolutionary options: either curtail it or employ it. This has important consequences for the host, since abnormal STAT3 function is associated with cancer development and other diseases. This review provides a comprehensive outline of how human viruses cope with STAT3-mediated inflammation and how this affects the host. Finally, we discuss STAT3 as a potential target for antiviral therapy.

Chronic exposure of nanomolar MC-LR caused oxidative stress and inflammatory responses in HepG2 cells

Low dose but long-term exposure of microcystin-LR (MC-LR) could induce human hepatitis and promote liver cancer according to epidemiological investigation results, but the exact mechanism has not been completely elucidated. In the present study, a chronic toxicity test of MC-LR exposure on HepG2 cells at 0.1-30 nM for 83 d was conducted under laboratory conditions. The western blot assay result revealed that MC-LR entered HepG2 cells, even at the concentration of 0.1 nM, after 83 d of exposure, but no cytotoxicity was observed in the HepG2 cells, as determined by the CCK-8 and LDH tests. However, the results of the DCF fluorescence assay showed that the intracellular ROS level in the 30 nM MC-LR-treated cells was significantly higher than that of the control cells, and 5 and 10 nM of MC-LR exposure totally increased the activity of SOD in HepG2 cells. These results indicate that MC-LR exposure at low concentration also induced excessive ROS in HepG2 cells. Additionally, long-term exposure of MC-LR at low concentration remarkably promoted the expression of NF-κB p65, COX-2, iNOS, TNF-α, IL-1β, and IL-6 in the cells, suggesting that long-term MC-LR exposure at low concentration can induce inflammatory reaction to HepG2 cells, which might account for MC-induced human hepatitis. Thus, we hypothesized that the pathogenesis of human hepatitis and hepatocarcinoma caused by MCs might be closely associated with oxidative stress and inflammation.

Three-Dimensional Cell Culture Model Utilization in Renal Carcinoma Cancer Stem Cell Research

Specific 3D conditions of cancer cell lines have been optimized over last years, with growing significance of serum-free and xeno-free culture variants. The choice of proper culture media enables cancer stem cells proliferation in primary and stable cell lines. To obtain renal cell cancer stem-like phenotype, we employed media dedicated for mesenchymal cells and adult stem cells. Developed RCC cell line 3D culture system enables effective drug testing, including tyrosine kinase inhibitor anti-cancer cell toxicity. To induce formation of 3D spheroids by RCC cell lines, StemXvivo and NutriStem media must be used. Usage of laminin- or poly-D-lysine coated plates enhances also the formation of spheroids in 3D-promoting media. Seeding is optimal with Caki-1 or ACHN cell lines as well as 786-O or HKCSC cells. Our bio-mimic 3D RCC cell culture model promotes cell viability and stem-related gene expression including E-cadherin, N-cadherin, HIF1, HIF2, VEGF, Sox2, Pax2, and Nestin. 3D spheroid formation ability and spheroid volume increase are disturbed upon drug treatment. Untreated 3D structures reach ~100 μm in diameter at the end of 14-day long experiment. Sorter-based cell cycle analysis and Ki-67 staining should be conducted to verify specific toxicity. We suggest that due to the more complex architecture 3D RCC culture is more relevant to investigate the in vivo-like tumor drug response.

Engineered Livers for Infectious Diseases

Engineered liver systems come in a variety of platform models, from 2-dimensional cocultures of primary human hepatocytes and stem cell-derived progeny, to 3-dimensional organoids and humanized mice. Because of the species-specificity of many human hepatropic pathogens, these engineered systems have been essential tools for biologic discovery and therapeutic agent development in the context of liver-dependent infectious diseases. Although improvement of existing models is always beneficial, and the addition of a robust immune component is a particular need, at present, considerable progress has been made using this combination of research platforms. We highlight advances in the study of hepatitis B and C viruses and malaria-causing Plasmodium falciparum and Plasmodium vivax parasites, and underscore the importance of pairing the most appropriate model system and readout modality with the particular experimental question at hand, without always requiring a platform that recapitulates human physiology in its entirety.

Increased incidence of cytomegalovirus coinfection in HCV-infected patients with late liver fibrosis is associated with dysregulation of JAK-STAT pathway

Herein, we examined the association between cytomegalovirus (CMV) coinfection and the progression of liver fibrosis in hepatitis C virus (HCV) infection, and investigated the effect of CMV coinfection on JAK-STAT pathway. CMV DNAemia was detected by PCR in DNA from controls (n = 120), and HCV patients with early (F0-F1, n = 131) and late (F2-F4, n = 179) liver fibrosis. By quantitative real time PCR (qRT-PCR), we examined the profile of 8 JAK-STAT transcripts in PBMCs RNA from 90 HCV patients (39 CMV positive and 51 CMV negative), 4 CMV mono-infected patients, and 15 controls. Our results demonstrated higher incidence of CMV in F2-F4 group than in control (OR 5.479, 95% CI 3.033–9.895, p < 0.0001) or F0-F1 groups (OR 2, 95% CI 1.238–3.181, p = 0.005). qRT-PCR showed downregulation of STAT2 (p = 0.006) and IRF7 (p = 0.02) in CMV positive group compared to CMV negative one. The downregulation of STAT2 and IRF7 was mainly in CMV positive patients with late fibrosis compared to CMV negative patients (p = 0.0007 for IRF7 and p = 0.01 for STAT2). Our results are the first to report that CMV coinfection is a possible risk factor for the progression of HCV-induced liver fibrosis, and thereby CMV screening and treatment are important for HCV patients.

Cytomegalovirus, Macrophages and Breast Cancer

The human cytomegalovirus (HCMV) is a betaherpesvirus that is highly host specific, infects among others epithelial cells and macrophages, and has been recently mentioned as having oncomodulatory properties. HCMV is detected in the breast tumor tissue where macrophages, especially tumor associated macrophages, are associated with a poor prognosis. In this review, we will discuss the potential implication of HCMV in breast cancer with emphasis on the role played by macrophages.

Persistent Cytomegalovirus Infection in Amniotic Membranes of the Human Placenta

Human cytomegalovirus (HCMV) is the leading viral cause of birth defects, including microcephaly, neurological deficits, hearing impairment, and vision loss. We previously reported that epithelial cells in amniotic membranes of placentas from newborns with intrauterine growth restriction and underlying congenital HCMV infection contain viral proteins in cytoplasmic vesicles. Herein, we immunostained amniotic membranes from 51 placentas from symptomatic and asymptomatic congenital infection with HCMV DNA in amniotic fluid and/or newborn saliva, intrauterine growth restriction, preterm deliveries, and controls. We consistently observed HCMV proteins in amniotic epithelial cells (AmEpCs) from infected placentas, sometimes with aberrant morphology. Primary AmEpCs isolated from mid-gestation placentas infected with pathogenic VR1814 proliferated and released infectious progeny for weeks, producing higher virus titers than late-gestation cells that varied by donor. In contrast to intact virion assembly compartments in differentiated retinal pigment epithelial cells, infected AmEpCs made dispersed multivesicular bodies. Primary AmEpCs and explants of amniochorionic membranes from mid-gestation placentas formed foci of infection, and interferon-β production was prolonged. Infected AmEpCs up-regulated anti-apoptotic proteins survivin and Bcl-x_L by mechanisms dependent and independent of the activated STAT3. Amniotic membranes naturally expressed both survivin and Bcl-x_L, indicating that fetal membranes could foster persistent viral infection. Our results suggest strengthening innate immune responses and reducing viral functions could suppress HCMV infection in the fetal compartment.

Human Cytomegalovirus Immediate-Early 1 Protein Rewires Upstream STAT3 to Downstream STAT1 Signaling Switching an IL6-Type to an IFNγ-Like Response

The human cytomegalovirus (hCMV) major immediate-early 1 protein (IE1) is best known for activating transcription to facilitate viral replication. Here we present transcriptome data indicating that IE1 is as significant a repressor as it is an activator of host gene expression. Human cells induced to express IE1 exhibit global repression of IL6- and oncostatin M-responsive STAT3 target genes. This repression is followed by STAT1 phosphorylation and activation of STAT1 target genes normally induced by IFNγ. The observed repression and subsequent activation are both mediated through the same region (amino acids 410 to 445) in the C-terminal domain of IE1, and this region serves as a binding site for STAT3. Depletion of STAT3 phenocopies the STAT1-dependent IFNγ-like response to IE1. In contrast, depletion of the IL6 receptor (IL6ST) or the STAT kinase JAK1 prevents this response. Accordingly, treatment with IL6 leads to prolonged STAT1 instead of STAT3 activation in wild-type IE1 expressing cells, but not in cells expressing a mutant protein (IE1dl410-420) deficient for STAT3 binding. A very similar STAT1-directed response to IL6 is also present in cells infected with a wild-type or revertant hCMV, but not an IE1dl410-420 mutant virus, and this response results in restricted viral replication. We conclude that IE1 is sufficient and necessary to rewire upstream IL6-type to downstream IFNγ-like signaling, two pathways linked to opposing actions, resulting in repressed STAT3- and activated STAT1-responsive genes. These findings relate transcriptional repressor and activator functions of IE1 and suggest unexpected outcomes relevant to viral pathogenesis in response to cytokines or growth factors that signal through the IL6ST-JAK1-STAT3 axis in hCMV-infected cells. Our results also reveal that IE1, a protein considered to be a key activator of the hCMV productive cycle, has an unanticipated role in tempering viral replication.

Our previous work has shown that the human cytomegalovirus (hCMV) major immediate-early 1 protein (IE1) modulates host cell signaling pathways involving proteins of the signal transducer and activator of transcription (STAT) family. IE1 has also long been known to facilitate viral replication by activating transcription. In this report we demonstrate that IE1 is as significant a repressor as it is an activator of host gene expression. Many genes repressed by IE1 are normally induced via STAT3 signaling triggered by interleukin 6 (IL6) or related cytokines, whereas many genes activated by IE1 are normally induced via STAT1 signaling triggered by interferon gamma (IFNγ). Our results suggest that the repression of STAT3- and the activation of STAT1-responsive genes by IE1 are coupled. By targeting STAT3, IE1 rewires upstream STAT3 to downstream STAT1 signaling. Consequently, genes normally induced by IL6 are repressed while genes normally induced by IFNγ become responsive to IL6 in the presence of IE1. We also demonstrate that, by switching an IL6 to an IFNγ-like response, IE1 tempers viral replication. These results suggest an unanticipated dual role for IE1 in either promoting or limiting hCMV propagation and demonstrate how a key viral regulatory protein merges two central cellular signaling pathways to divert cytokine responses relevant to hCMV pathogenesis.

A selective decoy-doxorubicin complex for targeted co-delivery, STAT3 probing and synergistic anti-cancer effect

A novel selective decoy oligodeoxynucleotide (dODN)-doxorubicin (DOX) complex is reported for cancer theranostics. It eliminates the use of a ligand or carrier for targeted delivery and disassembles into therapeutic dODN and DOX upon encountering over-activated STAT3 in cancer cells. Hence, in situ STAT3 probing and synergistic anti-cancer effect are attained at the same time.

Tumor control by human cytomegalovirus in a murine model of hepatocellular carcinoma

Although viruses can cause cancer, other studies reported the regression of human tumors upon viral infections. We investigated the cytoreductive potential of human cytomegalovirus (HCMV) in a murine model of human hepatocellular carcinoma (HCC) in severe-immunodeficient mice. Infection of HepG2 cells with HCMV resulted in the absence of tumor or in a limited tumor growth following injection of cells subcutaneously. By contrast all mice injected with uninfected HepG2 cells and with HepG2 cells infected with UV-treated HCMV did develop tumors without any significant restriction. Analysis of tumors indicated that in mice injected with HCMV-infected-HepG2 cells, but not in controls, a restricted cellular proliferation was observed parallel to a limited activation of the STAT3-cyclin D1 axis, decreased formation of colonies in soft agar, and activation of the intrinsic apoptotic pathway. We conclude that HCMV can provide antitumoral effects in a murine model of HCC which requires replicative virus at some stages that results in limitation of tumor cell proliferation and enhanced apoptosis mediated through the intrinsic caspase pathway.

Genetic and environmental determinants of population variation in interleukin-6, its soluble receptor and C-reactive protein: insights from identical and fraternal twins

Interleukin-6 and C-reactive protein are commonly assessed biomarkers linked to illness, obesity, and stressful life events. However, relatively little is known about their heritability. By comparing Caucasian twins from the Midlife in the US project (MIDUS), we estimated the heritability of IL-6, its soluble receptor, and CRP. Based on the hypothesis that adiposity might contribute more to IL-6 than to sIL-6r, we fit heritability models quantifying the extent to which each reflected genetic and environmental factors shared with obesity. Genetic influences on IL-6 and its receptor proved to be distinct. Further, the appearance of a heritable basis for IL-6 was mediated largely via shared paths with obesity. Supporting this conclusion, we confirmed that when unrelated adult controls are carefully matched to twin participants on BMI, age, gender and socioeconomic indices, their IL-6 is similar to the corresponding twins. In contrast, the effect of BMI on CRP was split between shared genetics and environmental influences. In conclusion, IL-6 is strongly affected by factors associated with obesity accounting for its lability and responsiveness to diet, life style and contemporaneous events.

Epigenetic regulation of human cytomegalovirus latency: an update

Human cytomegalovirus (HCMV) is a ubiquitous virus which infects 50-90% of the population worldwide. In immunocompetent hosts, HCMV either remains unnoticed or causes mild symptoms. Upon primary infection it establishes latent infection in a few cells. However, in certain situations where immunity is either immature or compromised, HCMV may reactivate and cause mortality and morbidity. Therefore, it is utmost important to understand how HCMV establishes latent infection and associated mechanisms responsible for its reactivation. Several mechanisms are involved in the regulation of latency including chromatin remodeling by an array of enzymes and microRNAs. Here we will describe the epigenetic regulation of HCMV latency. Further we will discuss the unique HCMV latency signature and patho-physiological relevance of latent HCMV infection.

The Complex Role of STAT3 in Viral Infections

Signal transducer and activators of transcription-3 (STAT3) regulates diverse biological functions including cell growth, differentiation, and apoptosis. In addition, STAT3 plays a key role in regulating host immune and inflammatory responses and in the pathogenesis of many cancers. Several studies reported differential regulation of STAT3 in a range of viral infections. Interestingly, STAT3 appears to direct seemingly contradictory responses and both pro- and antiviral roles of STAT3 have been described. This review summarized the currently known functions of STAT3 in the regulation of viral replication and pathogenesis of viral infections. Some of the key unanswered questions and the gap in our current understanding of the role of STAT3 in viral pathogenesis are discussed.

C-reactive protein is a biomarker of AFP-negative HBV-related hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is one of the most aggressive cancers worldwide and is associated with the high rates of morbidity and mortality. α-fetoprotein (AFP) is common used in diagnosis of HCC; however, a growing body of research is questioning the diagnostic power of AFP. There is, therefore, an urgent need to develop additional novel non-invasive techniques for the early diagnosis of HCC, particularly for patients with AFP-negative [AFP(-)] HCC. Accordingly, in the present study, we employed iTRAQ-based mass spectro-metry to analyze the plasma proteins of subjects with AFP(-) HBV-related HCC, AFP(+) HBV-related HCC and non-malignant cirrhosis. We identified 14 aberrantly expressed proteins specific to the HCC patients, including 10 upregulated and 4 downregulated proteins. We verified C-reactive protein (CRP) overexpression by ELISA and immunohistochemical staining of clinical samples. Per ROC curve analyses, CRP was positive in 73.3% of patients with HBV-related HCC, and CRP overexpression had significant diagnostic power for AFP(-) HBV-related HCC. Furthermore, we found that silencing CRP caused a >2-fold decease in HBV replication. Additionally, we determined that this reduction in HBV replication involved the interferon-signaling pathway. However, silencing CRP also promoted HCC invasion and migration in vitro. In conclusion, we demonstrated that CRP can serve as a diagnostic biomarker for AFP(-) HBV-related HCC.