Nishi Hirotaka, Ono Masanori, Ohno Shinichiro, Yamanaka Zenta, Sasaki Toru, Ohyashiki Kazuma, Ohyashiki Junko H, Kuroda Masahiko
Department of Obstetrics and Gynecology, Tokyo Medical University, Tokyo 160-0023, Japan.
Department of Molecular Pathology, Tokyo Medical University, Tokyo 160-8402, Japan.
Gynecol Oncol Rep. 2023 Jan 21;45:101138. doi: 10.1016/j.gore.2023.101138. eCollection 2023 Feb.
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.
We investigated the effect of hypoxia on miR-100 expression. We also explored the regulators of paclitaxel response under hypoxic conditions of cervical cancer.
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% O). 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.
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.
宫颈癌发生过程中出现的缺氧会导致化疗耐药。微小RNA的表达受缺氧调控，并与某些类型癌症的发生和进展相关。微小RNA-100（miR-100）是一种与鼻咽癌和口腔鳞状细胞癌相关的微小RNA，其在宫颈癌中的表达降低。本研究旨在确定缺氧对miR-100及其靶基因表达水平的影响，并探索缺氧条件下对紫杉醇的敏感性。
我们研究了缺氧对miR-100表达的影响。我们还探索了宫颈癌缺氧条件下紫杉醇反应的调节因子。
使用逆转录定量聚合酶链反应（RT-qPCR），我们发现宫颈癌细胞系SiHa和HeLa中miR-100在缺氧条件（1%氧气）下的表达显著更高。我们还证实人泛素特异性蛋白酶15（USP15）是miR-100的靶蛋白之一。缺氧和miR-100的过表达均降低了含有USP15 3'-非翻译区（其中包含miR-100结合位点）的荧光素酶报告基因的活性。此外，蛋白质免疫印迹分析表明缺氧抑制USP15蛋白的表达，而RT-qPCR显示缺氧诱导USP15 mRNA水平下调。我们还发现miR-100的过表达诱导紫杉醇耐药，从而降低药物对细胞死亡的治疗效果。
我们的结果与以下假设一致，即宫颈癌细胞在缺氧反应中过表达miR-100，且miR-100是USP15下调和失活的促进因子。
