Structural basis for allosteric PARP-1 retention on DNA breaks

Area of Science:

• Biochemistry
• Molecular Biology
• Cancer Therapeutics

Background:

• Poly(ADP-ribose) polymerase-1 (PARP-1) inhibitors (PARPi) are crucial in cancer treatment by trapping PARP-1 at DNA breaks.
• Existing PARPi exhibit variable trapping efficiencies despite targeting the enzyme's catalytic center.

Purpose of the Study:

• To investigate the allosteric mechanisms by which different PARPi influence PARP-1 retention or release from DNA breaks.
• To engineer a novel PARPi with enhanced cancer cell-killing capabilities by modulating PARP-1 allostery.

Main Methods:

• Structural analysis of diverse PARPi interactions with PARP-1.
• Allosteric modulation studies to assess PARP-1 release and retention dynamics.
• Development and evaluation of a novel PARPi compound.

Main Results:

• Structurally distinct PARPi were found to induce allosteric changes promoting either PARP-1 release or retention at DNA breaks.
• A newly synthesized PARPi converted an allosteric pro-release compound into a pro-retention agent.
• The engineered pro-retention PARPi demonstrated increased efficacy in killing cancer cells.

Conclusions:

• PARP-1 allostery is a critical determinant of inhibitor efficacy and DNA break trapping.
• Targeting PARP-1 allostery offers a promising strategy for developing more effective cancer therapeutics.
• The ability to control PARP-1 retention versus release has significant implications for clinical applications of PARPi.