Nucleotide-binding domain, leucine-rich repeat family with a caspase activation and recruitment domain 3 (NLRC3) participates in both immunity and cancer. The aim of this study was to determine the role of NLRC3 in human hepatocellular carcinoma (HCC) and the underlying mechanisms. We collected human liver tissues from nonalcoholic steatohepatitis (NASH), HCC, and adjacent normal tissues to characterize the pattern of NLRC3 expression by real-time quantitative polymerase chain reaction and immunohistochemistry. Then, we used the HCC cell line, HuH-7, transfected with small interfering RNA to silence the NLRC3 expression. 5-Ethynyl-2'-deoxyuridine assay, scratch assay, and transwell invasion assay were used for assessing proliferation, migration, and invasion, respectively. Flow cytometry and terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) assay were conducted to assess cell apoptosis. The expression of NLRC3 was reduced in human HCC tissues, compared with normal liver and nonalcoholic steatohepatitis tissues. After knocking down of NLRC3, the proliferation, migration, and invasion were increased in HuH-7 cells. And flow cytometry and TUNEL assay showed that HuH-7 cell apoptosis was suppressed after NLRC3 knockdown. As for the underlying mechanisms, knockdown of NLRC3 in HuH-7 cells was associated with the activation of Janus kinase 2/signal transducers and activators of transcription 3 (JAK2/STAT3) pathway under interleukin-6 (IL-6) stimulation. NLRC3 expression was downregulated in human HCC tissues. NLRC3 silencing in HuH-7 cells can promote the proliferation, migration, and invasion of hepatocellular carcinoma cells. JAK2/STAT3 pathway activation induced by IL-6 may be the underlying mechanism for HCC when NLRC3 expression is silenced. And the invasion of HuH-7 cells was partially suppressed by the STAT3 specific inhibitor (cryptotanshinone). Therefore, NLRC3 may play a significant role in HCC and might be a therapeutic target for the treatment of HCC.
Keywords: NLRC3; STAT3; hepatocellular carcinoma; innate immunity.
© 2020 International Federation for Cell Biology.