<i>MALAT1</i> Decreases the Sensitivity of Head and Neck Squamous Cell Carcinoma Cells to Radiation and Cisplatin

Abstract

Background/Aim: Two-thirds of head and neck squamous cell carcinoma (HNSCC) patients present with locally advanced (LA) stages and have a poor survival rate. The aim of this study was to investigate the roles of the long non-coding RNAs MALAT1 on radiation and cisplatin sensitivity of HNSCC cells. Materials and Methods: Clonogenic, cell viability, and apoptosis assays were performed in cells following MALAT1 knockdown using CRISPR/Cas9 system. Results: MALAT1 was overexpressed in HNSCC cell lines as compared to a non-tumorigenic cell line. The number of colonies formed after radiation was significantly reduced in MALAT1 knockdown cells. The IC₅₀ value of cisplatin in MALAT1 knockdown cells was lower than that of the control cells. MALAT1 knockdown resulted in cell cycle arrest at G₂/M phase, DNA damage and apoptotic cell death. Conclusion: MALAT1 knockdown enhanced the sensitivity of HNSCC cells to radiation and cisplatin partly through the induction of G₂/M cell cycle arrest resulting in DNA damage and apoptosis.