HN1 Promotes Proliferation, Metastasis and Attenuates the Chemosensitivity of HCC Cells to Oxaliplatin by Inhibiting Degradation of HMGB1 Through Interacting With TRIM28

Abstract

Background: The oxaliplatin-based chemotherapy has revealed an encouraging therapeutic efficacy for advanced hepatocellular carcinoma patients. However, the development of resistance limits its clinical utilization. In addition, the chemotherapy resistance in HCC is usually accompanied with other malignant phenotypes, such as cell proliferation and metastasis, which together result in poor prognosis of HCC patients. Therefore, efforts should be made to explore potential regulators which fuel multiple events of HCC progression.Methods: The qRT-PCR, western blot, immunohistochemistry and immunofluorescence were performed to measure mRNA and protein expression. MTT assay, colony formation and Transwell assay were performed to evaluate cell proliferation and metastasis. Flow cytometry was performed to test cell apoptosis. Alkaline Comet assay was performed to measure DNA lesions. Transmission electron microscope analysis provided potent testimony of autophagy. The role of HN1 on the malignant phenotypes of hepatoma carcinoma was demonstrated in vitro and in vivo.Results: The immunohistochemistry analysis of HCC patient tissues revealed that the expression of HN1 was higher in HCC tissues compared to adjacent tissues and was associated with worse prognosis. In vitro, HN1 knockdown inhibited proliferation and metastasis of HCC cells, whereas HN1 overexpression promoted their proliferation and metastasis. In addition, we found that HN1 knockdown sensitized HCC cells to oxaliplatin, which is companied with deteriorated DNA damage and increased cell apoptosis in oxaliplatin-treated HCC cells. In vivo, HN1 knockdown inhibited the tumor growth and metastasis, and promoted the anti-cancer efficiency of oxaliplatin. Mechanically, HN1 prevented HMGB1 from ubiquitination and degradation via autophagy-lysosome pathway, which is related to its interaction with TRIM28, and overexpression of HMGB1 can restore the malignant phenotypes of HN1 knockdown in HCC cells. Furthermore, we found that HN1 can regulate cellular autophagy via HMGB1, which is important to tumor-promoting effect of HN1.Conclusions: In conclusion, we systemically revealed the multiple functions of HN1 in HCC progression and the underlying molecular mechanism, which indicated that HN1 could be a promising therapeutic target for HCC treatment.