TXNIP overexpression suppresses proliferation and induces apoptosis in SMMC7221 cells through ROS generation and MAPK pathway activation

Thioredoxin binding protein (thioredoxin-interacting protein, TXNIP), known as vitamin D3 increase protein 1, has been identified as a tumor suppressor in various cancers such as pancreatic, breast, lung and thyroid cancer. However, the role of TXNIP in hepatocellular carcinoma cell proliferation and apoptosis remains unknown. In this study, we first used qRT-PCR, western blotting and immunohistochemistry to compare the expression of TXNIP between hepatocellular carcinoma tissues and tumor-adjacent normal liver tissues. In vitro, we explored the role of TXNIP in hepatocellular carcinoma progression via transfection of the pcDNA-3.1-TXNIP plasmid into SMMC7221 cells. Our results showed that the expression of TXNIP was significantly decreased in hepatocellular carcinoma tissues. Moreover, TXNIP over-expression inhibited hepatocellular carcinoma cell proliferation and induced apoptosis by triggering mitochondrial-mediated ROS generation and activating MAPK pathways. This study provides insight into the molecular mechanisms of TXNIP overexpression in liver cancer cell survival and apoptosis and indicated that TXNIP may be a novel promising agent for liver cancer treatment.