Hypoxia-induced paclitaxel resistance in cervical cancer modulated by miR-100 targeting of USP15

Hirotaka Nishi; Masanori Ono; Shinichiro Ohno; Zenta Yamanaka; Toru Sasaki; Kazuma Ohyashiki; Junko H Ohyashiki; Masahiko Kuroda

doi:10.1016/j.gore.2023.101138

Hypoxia-induced paclitaxel resistance in cervical cancer modulated by miR-100 targeting of USP15

Gynecol Oncol Rep. 2023 Jan 21:45:101138. doi: 10.1016/j.gore.2023.101138. eCollection 2023 Feb.

Authors

Hirotaka Nishi¹, Masanori Ono¹, Shinichiro Ohno², Zenta Yamanaka¹, Toru Sasaki¹, Kazuma Ohyashiki³, Junko H Ohyashiki⁴, Masahiko Kuroda²

Affiliations

¹ Department of Obstetrics and Gynecology, Tokyo Medical University, Tokyo 160-0023, Japan.
² Department of Molecular Pathology, Tokyo Medical University, Tokyo 160-8402, Japan.
³ Division of Hematology, Tokyo Medical University, Tokyo 160-0023, Japan.
⁴ Institute of Medical Science, Tokyo Medical University, Tokyo 160-8402, Japan.

Abstract

Objective: Hypoxia, which occurs during the development of cervical cancer, confers chemotherapy resistance. MicroRNA expression is regulated by hypoxia and is associated with the onset and progression of certain types of cancer. MicroRNA-100 (miR-100) is a microRNA, associated with nasopharyngeal and oral squamous cell carcinomas, whose expression is decreased in cervical cancer. This study aims to ascertain the effect of hypoxia on expression levels of both miR-100 and its target genes, as well as exploring the sensitivity to paclitaxel under hypoxic conditions.

Methods: We investigated the effect of hypoxia on miR-100 expression. We also explored the regulators of paclitaxel response under hypoxic conditions of cervical cancer.

Results: Using RT-qPCR, we found that expression of miR-100 in cervical cancer cell lines SiHa and HeLa is significantly higher under hypoxic conditions (1% O₂). We also confirmed that human ubiquitin-specific protease 15 (USP15) is the one of the target proteins of miR-100. Hypoxia and overexpression of miR-100 both reduced the activity of the luciferase reporter containing the 3'-untranslated region of USP15, which contains the miR-100 binding site. Furthermore, a western blot analysis showed that hypoxia suppresses the expression of the USP15 protein, while RT-qPCR showed hypoxia-induced downregulation of USP15 mRNA levels. We also discovered that overexpression of miR-100 induces paclitaxel resistance, thereby reducing the drug's therapeutic effect on cell death.

Conclusions: Our results are consistent with the hypothesis that cervical cancer cells overexpress miR-100 in response to hypoxia and that miR-100 is a facilitator of USP15 downregulation and inactivation.

Keywords: Apoptosis; Cervical cancer; Chemotherapy; Hypoxia; Paclitaxel resistance; miRNA.