KNOCKOUT OF THE HISTONE METHYLTRANSFERASE NSD1 LEADS TO A DECREASE IN CELL PROLIFERATION AND AN INCREASE IN SENSITIVITY TO CISPLATIN IN LARYNGEAL SQUAMOUS CELL CARCINOMA

Introduction. The histone methylation regulates gene expression and plays a role in genomic stability participating in DNA repair. Dimethylation of histone 3 lysine 36 (H3K36me²) is an important histone modification which is responsible for gene expression activation. H3K36me² is a product of methyltransferase activity of NSD1, NSD2, NSD3, and ASH1L proteins. NSD1 mutations are known to often occur in head and neck squamous carcinoma. The presence of NSD1 mutations highly correlates with increased survival, especially for patients with laryngeal cancer. The aim of this study was an in vitro investigation of the role of NSD1 in the cell proliferation of laryngeal squamous cell cancer and non-small lung cancer cells, as well as a study of the effect of disruption of the NSD1 gene expression on cisplatin treatment response. Material and Methods. Using TCGA, correlation analysis was performed to compare NSD1 wild type and mutant patient survival. NSD1 knockout cell lines models of laryngeal and non-small cell lung cancer were developed using the CRISPR/Cas9 system. The effect of NSD1 knockout on H3K36me2 level was evaluated by western blot. Proliferation and IC50 of cisplatin in control and knockout cells were studied as well. Results. It was demonstrated that NSD1 knockout decreased the H3K36me2 level and cell proliferation in laryngeal squamous cell cancer cells and increased the sensitivity of head and neck cancer cells to cisplatin treatment, while there was no effect of NSD1 knockout in a non-small cell lung cancer cell line. Conclusion. Based on the data obtained, it can be concluded that the NSD1 protein is a potential target for inhibitor development following in vitro and in vivo testing in head-neck squamous cell carcinoma models. More studies are needed for better understanding of the regulation of tumor cell growth by NSD1.