PARP1 and cancer: A recent work reported that an increased sensitivity to chemotherapy was observed in cancer cells with enforced miR-223 expression and reduced poly(ADP-ribose) polymerase-1 (PARP-1) [42], an enzyme which catalyzes the NAD+-dependent polymerization of long chains of poly-ADP ribose (PAR) onto itself in response to DNA damage, leading to DNA repair.