No abstract

Kaposi's sarcoma-associated herpesvirus (KSHV) is etiologically associated with Kaposi's sarcoma (KS), the most common AIDS-related malignancy. KSHV vIL-6 promotes KS development, but the exact mechanisms remain unclear. Here, we reported that KSHV vIL-6 enhanced the expression of DNA methyltransferase 1 (DNMT1) in endothelial cells,increased the global genomic DNA methylation, and promoted cell proliferation and migration. And this effect could be blocked by the DNA methyltransferase inhibitor, 5-azadeoxycytidine. We also showed that vIL-6 induced up-regulation of DNMT1 was dependent on STAT3 activation. Therefore, the present study suggests that vIL-6 plays a role in KS tumorigenesis partly by activating DNMT1 and inducing aberrant DNA methylation, and it might be a potential target for KS therapy.

miRNAs play important roles in lung adenocarcioma (LADC) progression. We previously found that miR-1290 expression was upregulated in LADC tissue and serum samples from patients with LADC, and correlated with prognosis. However, the biological role of miR-1290 in LADC and mechanism of such role are poorly understood. Here, we found that miR-1290 overexpression promoted LADC cell proliferation, cell cycle progression and invasion, while suppressing cell apoptosis in vitro. Furthermore, miR-1290 promoted tumor growth, invasion and metastasis in vivo. miR-1290 downregulated suppressor of cytokine signaling 4 (SOCS4) at both the mRNA and protein levels by targeting SOCS4. Reduced SOCS4 level reversed the inhibitory effect of miR-1290 downregulation on cell proliferation and invasion. miR-1290 activated the JAK/STAT3 and PI3K/AKT signaling pathways by targeting SOCS4. An inverse correlation was observed between miR-1290 and SOCS4 expression in LADC tissues. Clinicopathological characteristics analysis showed that SOCS4 expression was negatively associated with higher clinical stage and lymph node metastasis. These observations suggest that miR-1290 promotes LADC cell proliferation and invasion by targeting SOCS4.