Implications of viral infection in cancer development

Viral Infections and the Glutathione Peroxidase Family: Mechanisms of Disease Development

Significance: The glutathione peroxidase (GPx) family is recognized for its essential function in maintaining cellular redox balance and countering the overproduction of reactive oxygen species (ROS), a process intricately linked to the progression of various diseases including those spurred by viral infections. The modulation of GPx activity by viruses presents a critical juncture in disease pathogenesis, influencing cellular responses and the trajectory of infection-induced diseases. Recent Advances: Cutting-edge research has unveiled the GPx family's dynamic role in modulating viral pathogenesis. Notably, GPX4's pivotal function in regulating ferroptosis presents a novel avenue for the antiviral therapy. The discovery that selenium, an essential micronutrient for GPx activity, possesses antiviral properties has propelled us toward rethinking traditional treatment modalities. Critical Issues: Deciphering the intricate relationship between viral infections and GPx family members is paramount. Viral invasion can precipitate significant alterations in GPx function, influencing disease outcomes. The multifaceted nature of GPx activity during viral infections suggests that a deeper understanding of these interactions could yield novel insights into disease mechanisms, diagnostics, prognostics, and even chemotherapeutic resistance. Future Directions: This review aims to synthesize current knowledge on the impact of viral infections on GPx activity and expression and identify key advances. By elucidating the mechanisms through which GPx family members intersect with viral pathogenesis, we propose to uncover innovative therapeutic strategies that leverage the antioxidant properties of GPx to combat viral infections. The exploration of GPx as a therapeutic target and biomarker holds promise for the development of next-generation antiviral therapies. Antioxid. Redox Signal. 42, 623-639.

The adenoviral E4orf4 protein: A multifunctional protein serving as a guide for treating cancer, a multifactorial disease

Viruses exploit several cellular pathways to support their replication, and many of these virus-targeted pathways are also important for cancer growth. Consequently, studying virus-host interactions offers valuable insights into tumorigenesis and can suggest the development of novel anti-cancer therapies, with oncolytic viruses being one well-known example. The adenovirus E4orf4 protein, which disrupts several host regulatory pathways to facilitate viral infection, also functions as a potent anti-cancer agent when expressed independently. E4orf4 can selectively kill a wide range of cancer cell lines while sparing non-cancerous cells. Moreover, it effectively eliminated cancer in an in vivo Drosophila model without causing significant harm to normal tissues. In this study we provide evidence that an E4orf4-mimicking drug cocktail, comprising sublethal doses of four FDA-approved drugs targeting the pathways disrupted by E4orf4, significantly enhanced cancer cell death in many cancer cell types compared with individual drugs or less inclusive drug combinations. The quadruple drug cocktail was not toxic in non-cancerous cells. These findings provide a proof-of-principle for the potential application of virus-host interaction studies to design an effective E4orf4-based cancer therapy. Further investigation of E4orf4 interactions with the host cell will likely improve this E4orf4-based therapy by adding drugs that disrupt additional pathways. Crucially, the E4orf4-based approach offers a strategic advantage by avoiding the time-consuming development of novel drugs. Instead, it leverages existing drugs, including those that might be too toxic for use as monotherapies, by employing them at sublethal concentrations in combination. Thus, it provides a feasible and efficient method for advancing cancer therapy.

SARS-CoV-2 infection as a potential risk factor for the development of cancer

The COVID-19 pandemic has a significant impact on public health and the estimated number of excess deaths may be more than three times higher than documented in official statistics. Numerous studies have shown an increased risk of severe COVID-19 and death in patients with cancer. In addition, the role of SARS-CoV-2 as a potential risk factor for the development of cancer has been considered. Therefore, in this review, we summarise the available data on the potential effects of SARS-CoV-2 infection on oncogenesis, including but not limited to effects on host signal transduction pathways, immune surveillance, chronic inflammation, oxidative stress, cell cycle dysregulation, potential viral genome integration, epigenetic alterations and genetic mutations, oncolytic effects and reactivation of dormant cancer cells. We also investigated the potential long-term effects and impact of the antiviral therapy used in COVID-19 on cancer development and its progression.

Should We Expect an Increase in the Number of Cancer Cases in People with Long COVID?

The relationship between viral infections and the risk of developing cancer is well known. Multiple mechanisms participate in and determine this process. The COVID-19 pandemic caused by the SARS-CoV-2 virus has resulted in the deaths of millions of people worldwide. Although the effects of COVID-19 are limited for most people, a large number of people continue to show symptoms for a long period of time (long COVID). Several studies have suggested that cancer could also be a potential long-term complication of the virus; however, the causes of this risk are not yet well understood. In this review, we investigated arguments that could support or reject this possibility.

Analysis of Antioxidant and Antiviral Effects of Olive (Olea europaea L.) Leaf Extracts and Pure Compound Using Cancer Cell Model

The present study aims to assess the antioxidant and antiviral effectiveness of leaf extracts obtained from Olea europaea L. var. sativa and Olea europaea L. var. sylvestris. The total antioxidant activity was determined via both an ammonium phosphomolybdate assay and a nitric oxide radical inhibition assay. Both extracts showed reducing abilities in an in vitro system and in human HeLa cells. Indeed, after oxidative stress induction, we found that exposition to olive leaf extracts protects human HeLa cells from lipid peroxidation and increases the concentration of enzyme antioxidants such as catalase (CAT), superoxide dismutase (SOD), and glutathione peroxidase. Additionally, OESA treatment affects viral DNA accumulation more than OESY, probably due to the exclusive oleuropein content. In fact, subtoxic concentrations of oleuropein inhibit HSV-1 replication, stimulating the phosphorylation of PKR, c-FOS, and c-JUN proteins. These results provide new knowledge about the potential health benefits and mechanisms of action of oleuropein and oleuropein-rich extracts.

Viral Agents as Potential Drivers of Diffuse Large B-Cell Lymphoma Tumorigenesis

Among numerous causative agents recognized as oncogenic drivers, 13% of total cancer cases occur as a result of viral infections. The intricacy and diversity of carcinogenic processes, however, raise significant concerns about the mechanistic function of viruses in cancer. All tumor-associated viruses have been shown to encode viral oncogenes with a potential for cell transformation and the development of malignancies, including diffuse large B-cell lymphoma (DLBCL). Given the difficulties in identifying single mechanistic explanations, it is necessary to combine ideas from systems biology and viral evolution to comprehend the processes driving viral cancer. The potential for more efficient and acceptable therapies lies in targeted medicines that aim at viral proteins or trigger immune responses to either avoid infection or eliminate infected or cancerous cells. In this review, we aim to describe the role of viral infections and their mechanistic approaches in DLBCL tumorigenesis. To the best of our knowledge, this is the first review summarizing the oncogenic potential of numerous viral agents in DLBCL development.