DNMT1 and malignant colon neoplasm: By endogenous co-immunoprecipitation, we found KDM1A to bind DNMT1 and DNMT3B in two different cancer cell lines: when we immunoprecipitated endogenous KDM1A from whole-cell extracts of the colon cancer cell line HCT116, we detected DNMT1 and DNMT3B by western blotting (Figure 1B).