Potential molecular mechanism of radiation-induced cytotoxicity of Cetrimonium bromide to head and neck cancer cells

A previous study has shown that Cetrimonium bromide has a slight cytotoxicity to head and neck cancer cells due to the presence of the cationic quaternary amine group in this molecule that affects the function of mitochondria.The same study also found that the cytotoxicity of Cetrimonium bromide increased when combined with gamma radiation and this could be used to treat head and neck cancer in a mice in vivo tumor model.In the current study, an in vitro photochemical reaction between Cetrimonium chloride and tyrosine was investigated in order to understand the molecular mechanism of the in vivo observations and data. I found that Cetrimonium chloride could react with tyrosine upon simulated solar irradiation to produce an imine Schiff base which turned into cyano-tyrosine and a melanin polymer.It is possible that in the in vivo study mentioned earlier, the gamma radiation and Cetrimonium bromide together destroyed the tyrosine residues in some cellular proteins chemically, and as a result, tyrosine phosphorylation was inhibited in the cancer cells which slowed the growth of the tumor.