Activation of PI3K/AKT is involved in TINAG-mediated promotion of proliferation, invasion and migration of hepatocellular carcinoma

OBJECTIVE: Hepatocellular carcinoma (HCC) is a highly aggressive malignancy that has a poor prognosis. Through the literatures, TINAG significantly participated in the processes of the renal-associated diseases, but there were no studies about the roles of TINAG in the HCC development. Hence, we attempted to use the HCC samples collected by ourselves to reveal the clinical significance and prognostic impact of TINAG in HCC. METHODS: We first measured the expression level of TINAG in HCC on the basis of TCGA database. Then, real time quantitative reverse transcription PCR (RT-qPCR) was used to examine the expression level of TINAG in 100 pairs of HCC tissues and corresponding adjacent non-tumor tissues, as well as HCC cell lines (HepG2, HB611, HHCC, and Hep3B). Moreover, Kaplan-Meier method and COX's proportional hazards model were utilized to perform the survival and prognosis analyses using the clinical data collected by ourselves. After knockdown of TINAG, the cell proliferation, invasion and migration capacities of HepG2 and Hep3B cells were evaluate by counting kit-8 (CCK-8) assay (24 h, 48 h, 72 h, and 96 h post-cultivation), clone formation experiment, would-healing, and invasion as well as migration assays. To further explore whether the dys-regulated TINAG expression regulates the HCC progression and prognosis, protein biomarkers of PI3K signaling pathway, including AKT, p-AKT, PI3K, p-PI3K, p70S6K, and p-p70S6K were measured based on western blotting analysis. RESULTS: According to the data of TCGA database, clinical patients, and HCC cell lines, TINAG was highly expressed in HCC compared with normal. Relationship of TINAG expression level with the clinicopathological factors implicated that the high expression of TINAG was significantly associated with pathologic stage, pathologic-node, and pathologic-metastasis. Univariate as well as multivariate COX analysis indicated that TINAG expression and pathologic metastasis can serve as the independent prognostic factor for overall survival of HCC. After TINAG knockdown in HepG2 and Hep3B cells, cell proliferation rate, the colony numbers, and the invasive and migratory capacity were found to be suppressed. Remarkably, western blot results showed that reduction of TINAG remarkably decreased p-AKT, p-PI3K, and p-p70S6K expression level in HepG2 and Hep3B cells. CONCLUSION: Collectively, our results underscore the significance of TINAG in HCC progression and prognosis, and TINAG might be a novel candidate oncogene in HCC. These results propose that targeting TINAG might offer future clinical utility in HCC.