Selective Loss of PARG Restores PARylation and Counteracts PARP Inhibi…
강민실
Journal Club
0
1288
2022.01.05 00:28
Date: 2021.12.28
Selective Loss of PARG Restores PARylation and Counteracts PARP Inhibitor-Mediated Synthetic Lethality
Cancer Cell, Volume 33, Issue 6, 11 June 2018, Pages 1078-1093.e12
Highlights
• Endogenous PARG activity is crucial for the success of PARP inhibition therapy
• PARG suppression restores downstream PARP1 signaling upon PARP inhibitor treatment
• PARG depletion results in new vulnerabilities that can be exploited therapeutically
• PARG-negative clones are pre-existing in cancers relevant for PARPi therapy
Summary
Inhibitors of poly(ADP-ribose) (PAR) polymerase (PARPi) have recently entered the clinic for the treatment of homologous recombination (HR)-deficient cancers. Despite the success of this approach, drug resistance is a clinical hurdle, and we poorly understand how cancer cells escape the deadly effects of PARPi without restoring the HR pathway. By combining genetic screens with multi-omics analysis of matched PARPi-sensitive and -resistant Brca2-mutated mouse mammary tumors, we identified loss of PAR glycohydrolase (PARG) as a major resistance mechanism. We also found the presence of PARG-negative clones in a subset of human serous ovarian and triple-negative breast cancers. PARG depletion restores PAR formation and partially rescues PARP1 signaling. Importantly, PARG inactivation exposes vulnerabilities that can be exploited therapeutically.
Selective Loss of PARG Restores PARylation and Counteracts PARP Inhibitor-Mediated Synthetic Lethality
Cancer Cell, Volume 33, Issue 6, 11 June 2018, Pages 1078-1093.e12
Highlights
• Endogenous PARG activity is crucial for the success of PARP inhibition therapy
• PARG suppression restores downstream PARP1 signaling upon PARP inhibitor treatment
• PARG depletion results in new vulnerabilities that can be exploited therapeutically
• PARG-negative clones are pre-existing in cancers relevant for PARPi therapy
Summary
Inhibitors of poly(ADP-ribose) (PAR) polymerase (PARPi) have recently entered the clinic for the treatment of homologous recombination (HR)-deficient cancers. Despite the success of this approach, drug resistance is a clinical hurdle, and we poorly understand how cancer cells escape the deadly effects of PARPi without restoring the HR pathway. By combining genetic screens with multi-omics analysis of matched PARPi-sensitive and -resistant Brca2-mutated mouse mammary tumors, we identified loss of PAR glycohydrolase (PARG) as a major resistance mechanism. We also found the presence of PARG-negative clones in a subset of human serous ovarian and triple-negative breast cancers. PARG depletion restores PAR formation and partially rescues PARP1 signaling. Importantly, PARG inactivation exposes vulnerabilities that can be exploited therapeutically.
