Abstract

Background/Aim: Nitric oxide (NO) functions have been studied in many cancer types, but rarely in head and neck squamous cell carcinoma (HNSCC). This study aimed to investigate the behavior of HNSCC cells following exposure to high NO (HNO). Materials and Methods: Two pairs of isogenic HNSCC cell lines (HN18/HN17, HN30/HN31) were used, and were treated with a NO donor for 72 h. Cell viability, cell cycle, apoptosis, invasion, and MMP activity were determined using MTT, flow cytometry, Matrigel invasion, and gelatinase zymography assays, respectively. Results: HNO induced HN18 and HN31 cell cycle progression in S and G2/M phases. Anti-invasion, MMP-2 inhibition, and apoptosis induction were observed in certain HNO-adapted cell lines. High NO did not affect MMP-9 activity in all cell lines. Conclusion: NO enhanced cell cycle progression and apoptosis but inhibited cell invasion in HNSCC cells.