SM-1: A Promising Radiation Sensitizer for Head and Neck Cancer

Method: The MTT method was used to detect the effect of SM-1 on the viability of head and neck cancer cell lines HONE1, HSC2, and CAL27. The effects of SM-1 combined with radiation on the survival index of HONE1, HSC2, and CAL27 cell lines were determined by plate clone assay. Flow cytometry was used to investigate the effects of SM-1 and radiation combination on cell apoptosis and cell cycle in head and neck cancer cells, and western blot experiments were performed to detect the expression of apoptosis and cell cycle-related proteins. Finally, a xenograft tumor model of CAL27 was established to evaluate the anti-tumor effect of SM-1 combined with radiation in vivo.\n\nResults: In vitro, SM-1 effectively inhibited the viability of head and neck cancer cell lines HONE1, HSC2, and CAL27, and showed synergistic anti-proliferative activity in combination with radiation. Moreover, SM-1 exhibited a higher anti-tumor effect on head and neck cancer than the positive drug Debio1143, and significantly increased the sensitivity of head and neck cancer cells to radiation. Flow cytometry and western blot experiments showed that SM-1 caused G2/M phase arrest in head and neck cancer cells, and down-regulated the expression levels of cyclinB1 and cdc2 proteins. SM-1 activated caspase3 activity and induced apoptosis of head and neck cancer cells by promoting PARP1 cleavage. In vivo, SM-1 combined with radiation demonstrated a good anti-tumor effect.\n\nConclusion: The results of this study indicate that SM-1 is a promising candidate drug for anti-tumor therapy, as it significantly enhances the sensitivity of head and neck cancer cells to radiation and has great potential in the development of radiation sensitizer (which has certain reference value for the research and development of radiation sensitizer). Further investigation is warranted in clinical trials of combined radiotherapy.