Objective: This study was aimed to investigate the expression characteristics of MIIP in hepatocellular carcinoma (HCC), and to further explore whether it can inhibit the malignant progression of this disease via regulating AKT expression.
Patients and methods: Real-time quantitative PCR (qRT-PCR) was performed to examine the expression of MIIP in tumor and paracancerous tissue specimens of 39 patients with HCC, and to analyze the interplay between MIIP expression and clinical indicators and prognosis of HCC patients. At the same time, in HCC cell lines, the expression of MIIP was further verified using qRT-PCR. In addition, MIIP overexpression and knockdown models were constructed using lentivirus in HCC cell lines (Bel-7402 and Hep3B), and the influence of MIIP on the biological function of HCC cells was analyzed through CCK-8 and transwell migration assays. Finally, luciferase reporting assay and cell reverse experiments were applied to further explore the potential molecular mechanism and the interaction between MIIP and AKT.
Results: The results of qRT-PCR showed that the expression level of MIIP in HCC tissue samples was remarkably lower than that in adjacent ones, with a statistically significant difference. Compared with patients with high expression of MIIP, patients with low MIIP expression had a higher occurrence of distant metastasis and a lower overall survival rate. Similarly, compared with control group, the proliferation and migration ability of HCC cells in MIIP knockdown group (sh-MIIP) was remarkably enhanced, while the opposite result was observed in MIIP overexpression group. In addition, qRT-PCR results also revealed that AKT and MIIP were negatively correlated in HCC tissues. At the same time, the results of luciferase reporter gene assay demonstrated that MIIP can be targeted by AKT through certain binding site. Additionally, cell reverse experiment found that there might exist a mutual regulation between MIIP and AKT, thereby jointly regulating the malignant progression of HCC.
Conclusions: MIIP expression is remarkably decreased both in HCC tissues and cell lines; meanwhile, the low expression of MIIP is positively correlated with the occurrence of distant metastasis and poor prognosis of patients with HCC. In addition, MIIP may be able to inhibit the malignant progression of HCC by modulating AKT expression.