Abstract
Laryngeal squamous cell carcinoma (LSCC) and hypopharyngeal squamous cell carcinoma (HPSCC) are two types of head and neck cancers with high incidence rates and relatively poor prognoses. The aim of the present study was to determine the effects of microRNA (miR/miRNA)-136-5p and its downstream target, Rho-associated coiled-coil containing protein kinase 1 (ROCK1), on LSCC and HPSCC progression and cisplatin sensitivity. The miRNA and protein expression levels in head and neck cancer cell lines were evaluated using reverse transcription-quantitative PCR and western blotting, respectively. MTT, wound healing assays, transwell assays and flow cytometry analysis were performed to measure cell properties. The binding between miR-136-5p and ROCK1 was detected using a dual-luciferase reporter assay. Autophagy double-labeled adenoviral infection assays were used to assess cell autophagy. The results showed that miR-136-5p was expressed in LSCC and HPSCC cells. Functional experiments showed that the expression of miR-136-5p in LSCC and HPSCC cells was negatively correlated with cell viability, invasion and migration. Additionally, miR-136-5p overexpression inhibited epithelial-mesenchymal transition, whereas miR-136-5p knockdown had the opposite effect. Dual-luciferase reporter assays confirmed the targeting relationship between miR-136-5p and ROCK1. miR-136-5p overexpression increased the cisplatin sensitivity of LSCC and HPSCC cells by reducing cell viability, as well as promoting cell apoptosis and autophagy. miR-136-5p overexpression decreased the expression levels of its downstream target ROCK1 and attenuated activity of the Akt/mTOR signaling pathway in cisplatin-treated LSCC and HPSCC cells. Conversely, miR-136-5p knockdown increased ROCK1 levels and decreased cisplatin sensitivity of the LSCC and HPSCC cells by increasing cell viability and inhibiting cell apoptosis, which was reversed by ROCK1 inhibition using the ROCK1 inhibitor, Y27632. Taken together, the results showed that the miR-136-5p/ROCK1 axis inhibits cell invasion and migration, and increases the sensitivity of LSCC and HPSCC cells to cisplatin.