- p300 regulates p53-dependent apoptosis after DNA damage in colorectal cancer cells by modulation of PUMA/p21 levels. Iyer, N.G., Chin, S.F., Ozdag, H., Daigo, Y., Hu, D.E., Cariati, M., Brindle, K., Aparicio, S., Caldas, C. Proc. Natl. Acad. Sci. U.S.A. (2004)