BACKGROUND: Resistance to cisplatin results in recurrence or relapse of cervical cancer in women. An understanding of the mechanisms of cisplatin resistance will be important to improve the efficacy of cisplatin treatment. The aim of this study was to investigate the role of microRNA-7-5p (mir-7-5p) in cisplatin-resistant cervical cancer cells in vitro.
MATERIAL AND METHODS: The expression levels of miR-7-5p were detected in cisplatin-resistant cervical cancer cells, HeLa, and SiHa cells (HPV16-positive), and in clinical tissue samples, using miR-7-5p inhibition and a luciferase reporter assay. Fifteen paired cervical cancer tissue samples and adjacent normal cervical tissues were obtained from 15 patients who underwent surgery for cervical cancer. Western blot and flow cytometry were used to investigate cell apoptosis. The expression of mir-7-5p was detected by quantitative real-time reverse transcription-polymerase chain reaction (qRT-PCR).
RESULTS: The level of miR-7-5p was increased in cisplatin-resistant HeLa and SiHa cervical cancer cells. Increased expression of miR-7-5p inhibited DNA repair by modulating the expression of poly (ADP-ribose) polymerase 1 (PARP-1), reducing energy consumption, and promoting autophagy via suppression of the expression of Bcl-2. These findings supported that increasing energy generation and reducing energy consumption, resulted in miR-7-5p maintaining energy homeostasis during cisplatin treatment.
CONCLUSIONS: The findings of this study showed that there was a protective role of miR-7-5p in cervical cancer cells treated with cisplatin and that miR-7-5p expression maintained energy homeostasis in cisplatin-resistant cervical cancer cells. However, miR-7-5p reduced energy consumption via inhibiting PARP-1 expression, and miR-7-5p increased energy generation by suppressing the expression of Bcl-2.

Keywords: Autophagy, Cisplatin, MicroRNAs, Poly(ADP-ribose) Polymerases