Two views of the protein structure of a PARP1 inhibitor complex.
Poly(ADP-ribose) polymerase (PARP) inhibitors, particularly Sanofi’s iniparib and AstraZeneca’s olaparib, have elicited both great excitement and significant disappointment in equal measure in recent years as researchers pursue these agents in the treatment of several types of cancer with poor prognoses.
What Are PARPs?
PARPs are a family of enzymes implicated in a host of key cellular processes, including chromosome stability, regulation of apoptosis, cell division, and transcriptional regulation and differentiation. A particularly important role of PARPs is in repairing DNA damage that results from everyday environmental stresses and DNA replication errors.
Major DNA Repair Pathways
PARP plays a central role in DNA repair, and researchers theorize that inhibiting PARP
would result in cancer cell death.
The potential anticancer activity of PARP inhibitors was first elucidated in 2005. Currently, PARP inhibitors are designed to target the catalytic site of PARP1 and inhibit PARP1 by greater than 90%. They are thought to function in the treatment of cancer by exploiting the concept of synthetic lethality.