The μ-opioid receptor (MOR) promotes tumor initiation in hepatocellular carcinoma

Abstract Hepatocellular carcinoma (HCC) is the most prevalent subtype of liver cancer. Anesthetic regimens possibly influence cancer development. Exploration of novel, effective targets for liver cancer is the current hotspot in cancer treatment. A previous study conducted by us has demonstrated that enhanced expression of the μ-opioid receptor (MOR) promotes cell proliferation, adhesion, migration, and tumorigenesis. The current study investigates whether MOR regulates self-renewal of hepatocellular carcinoma stem cells (HCSCs). We utilize cell function assays, siRNA, shRNA, flow cytometry sorting, and other molecular biology techniques for this purpose. The results indicate that MOR expression is positively related to hepatocarcinoma progression. Silencing MOR greatly reduce HCC-related tumorigenesis both in vitro and in vivo and significantly extend the survival of tumor-bearing mice. Moreover, MOR silencing will greatly reduce colony formation by HCC cells, indicating down-regulation of cancer initiation. In conclusion, these results establish that MOR can be a novel and reliable HCSC marker and a potential therapeutic target against HCC via MOR-NFAT signaling.