H2AX and cancer: MM129 and MM131, together with the third sulfonamide derivative of pyrazolo[4,3-e]tetrazolo[1,5-b][1,2,4]triazine (MM130), exhibited cytotoxic and genotoxic activity, as established using an alkaline/neutral comet assay and γ-H2AX staining in four cancer cell lines: HeLa, HCT-116, PC-3, and BxPC-3.