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

Comprehensive bioinformatics analysis of human cytomegalovirus pathway genes in pan-cancer

BACKGROUND

Human cytomegalovirus (HCMV) is a herpesvirus that can infect various cell types and modulate host gene expression and immune response. It has been associated with the pathogenesis of various cancers, but its molecular mechanisms remain elusive.

METHODS

We comprehensively analyzed the expression of HCMV pathway genes across 26 cancer types using the Cancer Genome Atlas (TCGA) and The Genotype-Tissue Expression (GTEx) databases. We also used bioinformatics tools to study immune invasion and tumor microenvironment in pan-cancer. Cox regression and machine learning were used to analyze prognostic genes and their relationship with drug sensitivity.

RESULTS

We found that HCMV pathway genes are widely expressed in various cancers. Immune infiltration and the tumor microenvironment revealed that HCMV is involved in complex immune processes. We obtained prognostic genes for 25 cancers and significantly found 23 key genes in the HCMV pathway, which are significantly enriched in cellular chemotaxis and synaptic function and may be involved in disease progression. Notably, CaM family genes were up-regulated and AC family genes were down-regulated in most tumors. These hub genes correlate with sensitivity or resistance to various drugs, suggesting their potential as therapeutic targets.

CONCLUSIONS

Our study has revealed the role of the HCMV pathway in various cancers and provided insights into its molecular mechanism and therapeutic significance. It is worth noting that the key genes of the HCMV pathway may open up new doors for cancer prevention and treatment.

Molecular characterization of plasma virome of hepatocellular carcinoma (HCC) patients

Hepatocellular carcinoma (HCC) stands as the most common cancer type, arising from various causes, and responsible for a substantial number of cancer-related fatalities. Recent advancements in viral metagenomics have empowered scientists to delve into the intricate diversity of the virosphere, viral evolution, interactions between viruses and their hosts, and the identification of viral causes behind disease outbreaks, the development of specific symptoms, and their potential role in altering the host's physiology. The present study had the objective of "Molecular Characterization of HBV, HCV, anelloviruses, CMV, SENV-D, SENV-H, HEV, and HPV viruses among individuals suffering from HCC." A total of 381 HCC patients contributed 10 cc of blood each for this study. The research encompassed the assessment of tumor markers, followed by molecular characterization of HBV, HCV, Anelloviruses (TTV, TTMV, and TTMDV), SENV-H and SENV-D viruses, HEV, CMV, and HPV, as well as histopathological examinations. The outcomes of this study revealed that majority of the HCC patients 72.4% (276/381) were male as compared to females. HCV infection, at 76.4% (291 out of 381), exhibited a significant association (p < 0.05) with HCC. Most patients displayed singular lesions in the liver, with Child Pugh Score Type B being the predominant finding in 45.2% of cases. Plasma virome analysis indicated the prevalence of TTMDV (75%), followed by TTMV (70%) and TTV (42.1%) among anelloviruses in HCC patients. Similarly, SENV-H (52%) was followed by SENV-D (20%), with co-infections at 15%. The presence of CMV and HEV among the HCC patients was recorded 5% each however 3.5% of the patients showed the presence of HPV. In conclusion, this study underscores that HCC patients serve as reservoirs for various pathogenic and non-pathogenic viruses, potentially contributing to the development, progression, and severity of the disease.

Friend or Foe? Exploring the Role of Cytomegalovirus (HCMV) Infection in Head and Neck Tumors

Although not regarded as an oncogenic pathogen, the human cytomegalovirus (HCMV) has been associated with a wide array of malignancies. Conversely, a number of studies report on possible anti-tumor properties of the virus, apparently mediated via HCMV-galvanized T-cell tumor killing; these were recently being investigated in clinical trials for the purposes of anti-cancer treatment by means of dendritic cell vaccines and HCMV-specific cytotoxic T cells. In the present study, we have analyzed the relation between a complement of head-and-neck tumors and HCMV infection across 73 countries worldwide using Spearman correlation, univariate and multivariate regression analysis. Intriguingly, HCMV was found to be pro-oncogenic in patients with nasopharyngeal carcinoma; contrarywise, the virus manifested an inverse (i.e., anti-tumor) association with the tumors of the lip/oral region and the salivary glands. Although this putative protective effect was noted initially for thyroid neoplasia and hypopharyngeal tumors as well, after multivariate regression analysis the connection did not hold. There was no association between laryngeal cancer and HCMV infection. It would appear that, depending on the tissue, HCMV may exert both protective and oncogenic effects. The globally observed protective feature of the virus could potentially be utilized in future therapeutic approaches for salivary tumors and neoplasia in the lip/oral region. As correlation does not necessarily imply causation, more in-depth molecular analyses from comprehensive clinical studies are warranted to substantiate our findings.

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

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

Cytomegalovirus infection may be oncoprotective against neoplasms of B-lymphocyte lineage: single-institution experience and survey of global evidence

Background

Although cytomegalovirus (CMV) is not considered tumorigenic, there is evidence for its oncomodulatory effects and association with hematological neoplasms. Conversely, a number of experimental and clinical studies suggest its putative anti-tumour effect. We investigated the potential connection between chronic CMV infection in patients with B-lymphocyte (B-cell) malignancies in a retrospective single-center study and extracted relevant data on CMV prevalences and the incidences of B-cell cancers the world over.

Methods

In the clinical single-center study, prevalence of chronic CMV infection was compared between patients with B-cell leukemia/lymphoma and the healthy controls. Also, global data on CMV seroprevalences and the corresponding country-specific incidences of B- lineage neoplasms worldwide were investigated for potential correlations.

Results

Significantly higher CMV seropositivity was observed in control subjects than in patients with B-cell malignancies (p = 0.035). Moreover, an unexpected seroepidemiological evidence of highly significant inverse relationship between country-specific CMV prevalence and the annual incidence of B-cell neoplasms was noted across the populations worldwide (ρ = −0.625, p < 0.001).

Conclusions

We try to draw attention to an unreported interplay between CMV infection and B-cell lymphomagenesis in adults. A large-scale survey across > 70 countries disclosed a link between CMV and B-cell neoplasms. Our evidence hints at an antagonistic effect of chronic CMV infection against B-lymphoproliferation.

CMV Seropositive Status Increases Heparanase SNPs Regulatory Activity, Risk of Acute GVHD and Yield of CD34+ Cell Mobilization

Heparanase is an endo-β-glucuronidase that is best known for its pro-cancerous effects but is also implicated in the pathogenesis of various viruses. Activation of heparanase is a common strategy to increase viral spread and trigger the subsequent inflammatory cascade. Using a Single Nucleotide Polymorphisms (SNP)-associated approach we identified enhancer and insulator regions that regulate HPSE expression. Although a role for heparanase in viral infection has been noticed, the impact of HPSE functional SNPs has not been determined. We investigated the effect of cytomegalovirus (CMV) serostatus on the involvement of HPSE enhancer and insulator functional SNPs in the risk of acute graft versus host disease (GVHD) and granulocyte-colony stimulating factor related CD34⁺ mobilization. A significant correlation between the C alleles of insulator rs4364254 and rs4426765 and CMV seropositivity was found in healthy donors and patients with hematological malignancies. The risk of developing acute GVHD after hematopoietic stem cell transplantation was identified only in CMV-seropositive patients. A significant correlation between the enhancer rs4693608 and insulator rs28649799 and CD34⁺ cell mobilization was demonstrated in the CMV-seropositive donors. It is thus conceivable that latent CMV infection modulates heparanase regulatory regions and enhances the effect of functional SNPs on heparanase function in normal and pathological processes.

Human Cytomegalovirus Is Associated with Lower HCC Recurrence in Liver Transplant Patients

Human cytomegalovirus (CMV) infection has been reported to compromise liver transplantation (LT) outcomes. Recent studies have shown that CMV has a beneficial oncolytic ability. The aim of this study was to investigate the impact of CMV on tumor recurrence in patients with hepatocellular carcinoma (HCC) who underwent liver transplantation (LT). This retrospective study enrolled 280 HCC patients with LT at our institute between January 2005 and January 2016. Their relevant demographic characteristics, pre- and post-LT conditions, and explant histology were collected. A CMV pp65 antigenemia assay was performed weekly following LT to identify CMV infection. A total of 121 patients (43.2%) were CMV antigenemia-positive and 159 patients (56.8%) were negative. A significantly superior five-year recurrence-free survival was observed among CMV antigenemia-positive patients compared with the CMV-negative group (89.2% vs. 79.9%, p = 0.049). There was no significant difference in overall survival between the positive and negative CMV antigenemia groups (70.2% vs. 75.3%, p = 0.255). The major cause of death was HCC recurrence in CMV antigenemia-negative patients (51.3%), whereas more CMV antigenemia-positive patients died due to other bacterial or fungal infections (58.3%). In the multivariate analysis, the independent risk factors for tumor recurrence included positive CMV antigenemia (p = 0.042; odds ratio (OR) = 0.44; 95% confidence interval (CI) = 0.20–0.97), microscopic vascular invasion (p = 0.001; OR = 3.86; 95% confidence interval (CI) = 1.78–8.36), and tumor status beyond the Milan criteria (p = 0.001; OR = 3.69; 95% CI = 1.77–7.71). In conclusion, in addition to the well-known Milan criteria, human CMV is associated with a lower HCC recurrence rate after LT. However, this tumor suppressive property does not lead to prolonged overall survival, especially in severely immunocompromised patients who are vulnerable to other infections.

Links between Infections, Lung Cancer, and the Immune System

Lung cancer is the leading disease of cancer-related deaths worldwide. Since the beginning of the 20th century, various infectious agents associated with lung cancer have been identified. The mechanisms that include systemic inflammatory pathways as effect of microbial persistence in the lung can secondarily promote the development of lung carcinogenesis. Chronic inflammation associated with lung-cancer infections is known to precede tumor development, and it has a strong effect on the response(s) to therapy. In fact, both viral and bacterial infections can activate inflammatory cells and inflammatory signaling pathways. In this review, an overview of critical findings of recent studies investigating associations between each of viral and bacterial pathogens and lung carcinoma is provided, with particular emphasis on how infectious organisms can interfere with oncogenic processes and all the way through immunity. Moreover, a discussion of the direct crosstalk between lung tumor development and inflammatory processes is also presented.

Viral Manipulation of the Host Epigenome as a Driver of Virus-Induced Oncogenesis

Tumorigenesis due to viral infection accounts for a high fraction of the total global cancer burden (15–20%) of all human cancers. A comprehensive understanding of the mechanisms by which viral infection leads to tumor development is extremely important. One of the main mechanisms by which viruses induce host cell proliferation programs is through controlling the host’s epigenetic machinery. In this review, we dissect the epigenetic pathways through which oncogenic viruses can integrate their genome into host cell chromosomes and lead to tumor progression. In addition, we highlight the potential use of drugs based on histone modifiers in reducing the global impact of cancer development due to viral infection.

Patients with Helicobacter pylori-positive gastric cancer with human cytomegalovirus infection have a low tendency of advanced lymphatic metastasis in a Chinese population

Recognized as a group I carcinogen for gastric cancer (GC) and a factor involved in the development of GC, Helicobacter pylori serves a major part in GC research. However, most studies have focused on H. pylori itself, ignoring the complicated pathogenic microbiological environment of GC and neglecting the synergistic or antagonistic effects of H. pylori with other pathogenic microorganisms. Increasing evidence has revealed that the human cytomegalovirus (HCMV) is present in several types of tumors and serves an important role in the neoplastic process of certain human malignant tumors, including GC. The aim of the present study was to explore the role of HCMV and H. pylori co-infection in GC. HCMV and H. pylori infection was analyzed in paired gastric tumor and peri-tumoral tissues from 134 (98 male and 36 female) patients using PCR. The results revealed that a total of 74 (55.2%) patients had H. pylori infection, 58 patients (43.3%) had HCMV infection, and 34 (25.4%) patients had both HCMV and H. pylori infection. Univariate and multivariate analyses demonstrated that H. pylori infection was independently associated with advanced lymphatic metastasis [P=0.007; odds ratio (OR)=3.51]. Furthermore, compared with HCMV-/H. pylori -, neither HCMV+/H. pylori - nor HCMV+/H. pylori + were associated with metastasis, but HCMV-/H. pylori + co-infection status was an independent risk factor for advanced lymphatic metastasis (P=0.005; OR=6.00). In conclusion, GC co-infected with HCMV and H. pylori exhibited a low tendency of lymph node metastasis. HCMV may interact with H. pylori to inhibit the process of lymphatic metastasis, and the mechanism requires further investigation.

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.

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.

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.

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.

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.