The Roles of the Virome in Cancer

Targeting the gut and tumor microbiome in cancer treatment resistance

Therapy resistance represents a significant challenge in oncology, occurring in various therapeutic approaches. Recently, animal models and an increasing set of clinical trials highlight the crucial impact of the gut and tumor microbiome on treatment response. The intestinal microbiome contributes to cancer initiation, progression, and formation of distant metastasis. In addition, tumor-associated microbiota is considered a critical player in influencing tumor microenvironments and regulating local immune processes. Intriguingly, numerous studies have successfully identified pathogens within the gut and tumor microbiome that might be linked to a poor response to different therapeutic modalities. The unfavorable microbial composition with the presence of specific microbes participates in cancer resistance and progression via several mechanisms, including upregulation of oncogenic pathways, macrophage polarization reprogramming, metabolism of chemotherapeutic compounds, autophagy pathway modulation, enhanced DNA damage repair, inactivation of a proapoptotic cascade, and bacterial secretion of extracellular vesicles, promoting the processes in the metastatic cascade. Targeted elimination of specific intratumoral bacteria appears to enhance treatment response. However, broad-spectrum antibiotic pretreatment is mostly connected to reduced efficacy due to gut dysbiosis and lower diversity. Mounting evidence supports the potential of microbiota modulation by probiotics and fecal microbiota transplantation to improve intestinal dysbiosis and increase microbial diversity, leading to enhanced treatment efficacy while mitigating adverse effects. In this context, further research concerning the identification of clinically relevant microbiome signatures followed by microbiota-targeted strategies presents a promising approach to overcoming immunotherapy and chemotherapy resistance in refractory patients, improving their outcomes.

The role and impact of viruses on cancer development

This review focuses on three major aspects of oncoviruses' role in cancer development. To begin, we discuss their geographic distribution, revealing that seven oncoviruses cause 20% of all human cancers worldwide. Second, we investigate the primary carcinogenic mechanisms, looking at how these oncogenic viruses can induce cellular transformation, angiogenesis, and local and systemic inflammation. Finally, we investigate the possibility of SARS-CoV-2 infection reactivating latent oncoviruses, which could increase the risk of further disease. The development of oncovirus vaccines holds great promise for reducing cancer burden. Many unanswered questions about the host and environmental cofactors that contribute to cancer development and prevention remain, which ongoing research is attempting to address.

Blood virome research in myalgic encephalomyelitis/chronic fatigue syndrome: challenges and opportunities

Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) is a debilitating disease with a complex clinical presentation and an unknown etiology. Various viral infections have been proposed as potential triggers of ME/CFS onset, but no specific pathogen has been identified in all cases of postinfectious ME/CFS. The symptomatology of the postacute sequelae of SARS-CoV-2, or long COVID, mirrors that of ME/CFS, with nearly half of long COVID patients meeting ME/CFS diagnostic criteria. The influx of newly diagnosed patients has reinvigorated interest in ME/CFS pathogenesis research, with an emphasis on viral triggers. This review summarizes the current understanding of ME/CFS research on viral triggers, including blood virome screening studies. To further elucidate the molecular basis of ME/CFS, there is a need to develop innovative bioinformatics tools capable of analyzing complex virome data and integrating multiomics information.

Role of the microbiota in response to and recovery from cancer therapy

Our understanding of how the microbiota affects the balance between response to and failure of cancer treatment by modulating the tumour microenvironment and systemic immune system has advanced rapidly in recent years. Microbiota-targeting interventions in patients with cancer are an area of intensive investigation. Promisingly, phase I-II clinical trials have shown that interventions such as faecal microbiota transplantation can overcome resistance to immune checkpoint blockade in patients with melanoma, improve therapeutic outcomes in treatment-naive patients and reduce therapy-induced immunotoxicities. Here, we synthesize the evidence showing that the microbiota is an important determinant of both cancer treatment efficacy and treatment-induced acute and long-term toxicity, and we discuss the complex and inter-related mechanisms involved. We also assess the potential of microbiota-targeting interventions, including bacterial engineering and phage therapy, to optimize the response to and recovery from cancer therapy.

Investigation of Epstein-Barr virus, Cytomegalovirus, Human herpesvirus 6, and Polyoma viruses (JC virus, BK virus) among Gastric cancer patients: A cross sectional study

Background and Aims

Gastric cancer is a significant global issue with a high death rate. This malignancy could be associated with several viral agents such as EBV, CMV, HHV-6, JCV, and BKV.

Objective

Evaluation of EBV, CMV, HHV-6 ,and JCV, BKV frequency among gastric cancer patients.

Methods

In this cross-sectional study, a total number of 60 gastric cancer specimens (32 male, 28 female) were retrieved from the pathology lab. Formalin-fixed paraffin-embedded tissue was used for molecular testing. DNA was extracted from samples, according to protocol, and used for PCR reaction. Polymerase chain reactions were used to assess CMV, EBV, HHV-6, JCV, and BKV frequency.

Results and Conclusion

The mean age of the participants was 61 years and 53.3% (32) of the participants were Male. A total number of 5 samples (8.34%) were infected with viral agents. Four male gastric samples were infected with EBV (6.67%) and only one female sample contained the BKV genome (1.67%). Totally 8.34% of the samples were infected with EBV and BKV. The CMV, HHV-6, and JCV genome was not detected in the samples. In conclusion, the presence of two viral agents including EBV and BKV among male and female samples respectively, and the genome of other viruses were not detected.

Gut virome in inflammatory bowel disease and beyond

OBJECTIVE

The gut virome is a dense community of viruses inhabiting the gastrointestinal tract and an integral part of the microbiota. The virome coexists with the other components of the microbiota and with the host in a dynamic equilibrium, serving as a key contributor to the maintenance of intestinal homeostasis and functions. However, this equilibrium can be interrupted in certain pathological states, including inflammatory bowel disease, causing dysbiosis that may participate in disease pathogenesis. Nevertheless, whether virome dysbiosis is a causal or bystander event requires further clarification.

DESIGN

This review seeks to summarise the latest advancements in the study of the gut virome, highlighting its cross-talk with the mucosal microenvironment. It explores how cutting-edge technologies may build upon current knowledge to advance research in this field. An overview of virome transplantation in diseased gastrointestinal tracts is provided along with insights into the development of innovative virome-based therapeutics to improve clinical management.

RESULTS

Gut virome dysbiosis, primarily driven by the expansion of Caudovirales, has been shown to impact intestinal immunity and barrier functions, influencing overall intestinal homeostasis. Although emerging innovative technologies still need further implementation, they display the unprecedented potential to better characterise virome composition and delineate its role in intestinal diseases.

CONCLUSIONS

The field of gut virome is progressively expanding, thanks to the advancements of sequencing technologies and bioinformatic pipelines. These have contributed to a better understanding of how virome dysbiosis is linked to intestinal disease pathogenesis and how the modulation of virome composition may help the clinical intervention to ameliorate gut disease management.

Torque teno virus and cancers: current knowledge

Aim: The aim of this systematic review is to assess the current knowledge about the relationship between Torque teno virus (TTV) and cancer in different settings. Methods: A systematic search was conducted in Medline via PubMed, Embase and Cochrane Library from the inception to the end of January 2023. Results: 34 articles were included in the qualitative synthesis of this review and 2145 patients with solid tumors have been analyzed. The most prevalent cancer types were hepatocellular carcinoma (HCC) and lung cancer. Conclusion: TTV has proven its role as a marker of functional immune competence in the setting of hematopoietic stem cell transplantation (HSCT), but in the oncological field is yet to be defined.

Metagenomic insights into the plasma virome of Brazilian patients with prostate cancer

Growing evidence suggests that metavirome changes could be associated increased risk for malignant cell transformation. Considering Viruses have been proposed as factors for prostate cancer induction. The objective of this study was to examine the composition of the plasma metavirome of patients with prostate cancer. Blood samples were obtained from 49 male patients with primary prostate adenocarcinoma. Thirty blood donors were included as a control group. The obtained next-generation sequencing data were analyzed using a bioinformatic pipeline for virus metagenomics. Viral reads with higher abundance were assembled in contigs and analyzed taxonomically. Viral agents of interest were also confirmed by qPCR. Anelloviruses and the Human Pegivirus-1 (HPgV-1) were the most abundant component of plasma metavirome. Clinically important viruses like hepatitis C virus (HCV), cytomegalovirus and human adenovirus type C were also identified. In comparison, the blood donor virome was exclusively composed of torque teno virus types (TTV) types. The performed HPgV-1 and HCV phylogeny revealed that these viruses belong to commonly detected in Brazil genotypes. Our study sheds light on the plasma viral abundance in patients with prostatic cancer. The obtained viral diversity allowed us to separate the patients and controls, probably suggesting that malignant processes may influence virome composition. More complex and multiple approach investigations are necessary to examine the likely causal relationship between metavirome and its nvolvement in prostate cancer.