33-kDa ANXA3 Knockdown Suppresses Carcinogenesis, Angiogenesis and Enhances Chemoresistance of Hepatocarcinoma via Inhibiting ERK, PI3K/Akt-HIF and Intrinsic Apoptosis Pathways

Background: As a member of annexin family proteins, annexin A3 (ANXA3) has 36-kDa and 33-kDa isoforms, which plays important roles in aggressiveness, tumorigenesis and drug resistance in tumors. Previous studies mainly focused on the role of total ANXA3 in cancers without distinguishing the distinction between the two isoforms, the role of 33-kDa ANXA3 in cancer remains unclear. Current work established the potential role and regulation mechanism of 33-kDa ANXA3 in hepatocarcinoma. Methods: The expression patterns of ANXA3, CRKL, Rac1, c-Myc and pAkt were analyzed in hepatocarcinoma specimens by western blotting; The biological function of 33-kDa ANXA3 in hepatocarcinoma cell growth, metastasis, apoptosis, angiogenesis, chemoresistance and the underlying molecular mechanism were investigated using gain-of-function strategyin vitro or in vivo. Findings: 33-kDa ANXA3 protein was significantly upregulated in cancerous tissues compared with paracancerous non-tumor liver tissues of hepatocarcinoma patients. Its stable knockdown decreased the in vivo tumor growing velocity and malignancy of hepatocarcinoma HepG2 cells transplanted in nude mice. The in vitro experimental results indicated 33-kDa ANXA3 knockdown suppressed proliferative, colony forming, migrative and invasive abilities of HepG2 cells through downregulating CRKL, Rap1b, Rac1, pMEK, pERK2 and c-Myc in ERK pathway; inhibited angiogenesis ability of HepG2 cells through inactivating PI3K/Akt-HIF pathway; induced apoptosis and enchanced chemoresistance of HepG2 cells through increasing Bax/decreasing Bcl-2 expressions and inactivating caspase 9/caspase 3 in intrinsic apoptosis pathway. Accordingly, CRKL, Rac1, c-Myc and pAkt were also upregulated in cancerous tissues compared with paracancerous non-tumor liver tissues of hepatocarcinoma patients. Interpretation: 33-kDa ANXA3 plays vital role in hepatocarcinoma malignancy, angiogenesis and chemoresistance. It is of potential use in prognosis and therapeutics for hepatocarcinoma. Funding Statement: This work was supported by grants from National Natural Science Foundation of China (81672737, 81272186, 31900517) and Natural Science Foundation of Liaoning (LZ2019003, 20181550168, LQ2017001). Declaration of Interests: The authors declare no potential conflicts of interest. Ethics Approval Statement: Tissue use and study protocol were approved by the Medical Ethics Committee of Dalian Medical University. Informed consent was obtained from each patient. All experiment methods were performed in accordance with the relevant guidelines and regulations.