Objective: Hepatitis B X-interacting protein (HBXIP) interacts with hepatitis B virus X protein to participate in the replication of the hepatitis B virus and carcinogenesis. Cellular growth and metastasis of non-small-cell lung cancer (NSCLC) are repressed by HBXIP inhibition. However, the role and mechanism of HBXIP on NSCLC cell growth remain unknown.
Materials: Expression of HBXIP was assessed by qRT-PCR and Western blot. siRNA targeting HBXIP was applied to detect cell viability and proliferation by MTT and colony formation assays. In vivo tumor growth was assessed, and anti-tumor immunity was determined by flow cytometry. The downstream partners involved in HBXIP-mediated tumorigenesis were detected by Western blot.
Results: Expression of HBXIP and neuropilin1-1 (NRP-1) was higher in NSCLC tissues and cells than in paracancerous tissues and human lung epithelial cells. siRNA-mediated knockdown of HBXIP decreased the cell viability of NSCLC and suppressed proliferation. Protein expression of Lin28B and NRP-1 was reduced by the knockdown of HBXIP, and over-expression of Lin28B attenuated the HBXIP silence-induced decrease of NRP-1. In vivo tumor growth was suppressed by HBXIP silencing, and the knockdown of HBXIP enhanced anti-tumor immunity through the increase of CD4+ and CD8+ T lymphocytes.
Conclusion: Down-regulation of HBXIP reduced Lin28B-mediated NRP-1 to suppress NSCLC cell growth and enhance anti-tumor immunity.
Keywords: HBXIP; Lin28B; NRP-1; anti-tumor immunity; non-small cell lung cancer.
© 2021 by the Association of Clinical Scientists, Inc.