CHEK1 and neoplasm: The results showed that 6, 16–19 had remarkable inhibitory effects against five tumor cell lines (A549, HepG2, HeLa, MDA-MB-231, and HCT116) with IC50 values ranging from 6.69–33.46 μM, and showed down-regulating the expression of ATR (ataxia telangiectasia mutated and RAD3-related) and CHK1 (checkpoint kinase 1) levels in HCT116 and A549 cell lines.