ATR Inhibitor AZD6738 Increases the Sensitivity of Colorectal Cancer Cells to 5-Fluorouracil by Inhibiting Repair of DNA Damage

In vitro, the AZD6738/5‑FU combination increased the number of mitotic cells according to flow cytometry, decreased the checkpoint kinase 1 phosphorylation levels and increased cleaved caspase‑3 and phosphorylated form of H2A.X variant histone levels according to western blotting, and decreased the proliferation rate of four colon cancer cell lines according to cell viability experiments.