Overexpression of ADAM9 decreases radiosensitivity of hepatocellular carcinoma cell by activating autophagy

ABSTRACT

A disintegrin and a metalloprotease (ADAM)9 upregulated within human hepatocellular carcinoma (HCC) cells, but its effect on HCC radiosensitivity remains unknown. The present work aimed to examine the effect of ADAM9 on HCC radiosensitivity and to reveal its possible mechanism, which may be helpful in identifying a potential therapeutic strategy. Changes in ADAM9 expression after X-ray irradiation were identified using western blot, qRT-PCR, and immunofluorescence. ADAM9 stable knockdown and overexpression cell lines were constructed using lentivirus packaging. The radiosensitivity of HCC cells with altered ADAM9 expression was examined by CCK-8 assays, subcutaneous tumorigenesis experiments, and clone formation assays. This study also determined how autophagy affected HCC cell radiosensitivity. Furthermore, ADAM9, p62 and Bax expressions in HCC tissues that were removed after radiotherapy were detected by immunohistochemistry, and the relationship among the levels of these molecules was statistically analyzed. The level of ADAM9expression in HCC cells increased after X-ray irradiation. Through CCK-8 assays, subcutaneous tumorigenesis experiments, and clone formation assays, this work discovered the increased MHCC97H cell radiosensitivity after ADAM9 knockdown, and the radiosensitivity of Huh7 cells decreased after the overexpression of ADAM9. Furthermore, ADAM9 induced HCC cell autophagy via downregulating Nrf2 expression, while autophagy inhibition or induction reversed the effects of altered ADAM9 expression on radiosensitivity. Moreover, ADAM9 level showed a negative correlation with Bax and p62 expression within HCC tissues after radiotherapy. Taken together, ADAM9 decreased the radiosensitivity of HCC cells, and autophagy mediated this process.

KEYWORDS:

• HCC
• ADAM9
• radiosensitivity
• autophagy

Highlights

• Radiation increases the level of ADAM9 in HCC cells.

• ADAM9 decreases the radiosensitivity of HCC cell lines by inducing autophagy.

• ADAM9 induced autophagy via downregulating Nrf2 expression in the cytoplasm.

Disclosure statement

All authors have declared no competing interest.

Authors’ contributions

Yinying Dong carried out study conception. Lijin Zhu conducted experiments prepared for drafting the original manuscript. Li Yu and Xinjia He were responsible for analyzing data. Yingju Wang and Peng Jiang were in charge of data curation. Rong Yu and Wei Li were in charge of acquiring funding. Bin Dong and Xiang Wang made contribution to manuscript writing or reviewing and intellectual input providing. Yuanyuan Zhao made contribution to supervision and project administration.

Data availability

Datasets utilized during this work can be accessed from related authors after reasonable request.

Ethics approval and consent to participate

The Research Ethics Committee of Fudan University Zhongshan Hospital (Shanghai, China) approved the use of human subjects (Identification code: B2013-150). The Ethics Committee for Animal Experiments of the Qingdao University Animal Care Committee, Shandong, China approved each animal protocol (Permit Number: 2008-0039).

Additional information

Funding

The present work was funded by the National Outstanding Youth Science Fund Project of National Natural Science Foundation of China under Grant [number 81803058]; the Chinese Society of Clinical Oncology under Grant [number Y-QL2019-0337].