Kaposi's sarcoma-associated herpesvirus-encoded viral FLICE inhibitory protein (vFLIP) K13 suppresses CXCR4 expression by upregulating miR-146a

miRNAs in the pathogenesis of oncogenic human viruses

Tumor viruses are a class of pathogens with well established roles in the development of malignant diseases. Numerous bodies of work have highlighted miRNAs (microRNAs) as critical regulators of tumor pathways and it is clear that the dysregulation of cellular miRNA expression can promote tumor formation. Tumor viruses encode their own miRNAs and/or manipulate the expression of cellular miRNAs to modulate their host cell environment, thereby facilitating their respective infection cycles. The modulation of these miRNA responsive pathways, however, often influences certain signal transduction cascades in ways that favor tumorigenesis. In this review, we discuss the roles of virally-encoded and virally-regulated cellular miRNAs in the respective viral life cycles and in virus associated pathogenesis.

Correlation between pre-miR-146a C/G polymorphism and gastric cancer risk in Chinese population

AIM: To investigate the association between pre-miR-146a C/G polymorphism and gastric cancer risk.

METHODS: We performed a hospital-based, case-control study using polymerase chain reaction-restriction fragment length polymorphism method in 608 individuals (304 gastric cancer patients and 304 age and sex matched cancer-free controls).

RESULTS: The frequencies of pre-miR-146a C/G genotypes in the case group were significantly different from those in the control groups (P = 0.037). Compared with CC genotype carriers, subjects with the variant genotypes (GC + GG) had a 58% increased risk of gastric cancer (adjusted OR = 1.58, 95% CI: 1.11-2.20, P = 0.009). Moreover, a higher gastric cancer risk was especially evident in younger individuals aged ≤ 58 years, nonsmokers, and males (adjusted OR = 1.76, 95% CI: 1.08-2.87, P = 0.024; adjusted OR = 1.55, 95% CI: 1.06-2.28, P = 0.025; adjusted OR = 1.53, 95% CI: 1.04-2.27, P = 0.033; respectively).

CONCLUSION: Pre-miR-146a C/G polymorphism might be associated with an elevated risk of gastric cancer in Chinese population.

Molecular biology of Kaposi's sarcoma-associated herpesvirus and related oncogenesis

Kaposi's Sarcoma-associated Herpesvirus (KSHV), also known as human herpesvirus 8 (HHV-8), is the most recently identified human tumor virus,and is associated with the pathogenesis of Kaposi's sarcoma and two lymphoproliferative disorders known to occur frequently in AIDS patients-primary effusion lymphoma and multicentric Castleman disease. In the 15 years since its discovery, intense studies have demonstrated an etiologic role for KSHV in the development of these malignancies. Here, we review the recent advances linked to understanding KSHV latent and lytic life cycle and the molecular mechanisms of KSHV-mediated oncogenesis in terms of transformation, cell signaling, cell growth and survival, angiogenesis, immune invasion and response to microenvironmental stress, and highlight the potential therapeutic targets for blocking KSHV tumorigenesis.