Integrative functional proteomics identifies PARP1 protein complex differences and PARP inhibitor-mediated DDR and AKT-mTOR signaling in ovarian carcinoma: Phosphoproteomics

ABSTRACT: BRCA1/2-deficient ovarian carcinoma (OC) has been shown to be particularly sensitive to PARP inhibitors (PARPis) and BRCA1/2 mutation status is currently used as a predictive biomarker for PARPi therapy. Despite eliciting major clinical benefit for the majority of patients, a significant proportion of BRCA1/2-deficient OC tumors do not respond to PARPis for reasons that are incompletely understood. Using an integrated chemical, phospho- and ADP-ribosylation proteomics approach we sought to develop additional mechanism-based biomarker candidates for PARPi therapy in OC and identify new targets for combination therapy to overcome primary resistance. Chemical proteomics with PARPi baits in a BRCA1-isogenic OC cell line pair, as well as patient-derived BRCA1-profiecient and deficient tumor samples, and subsequent validation by co-immunoprecipitation showed differential PARP1 and PARP2 protein complex composition with Ku70 and Ku80 in PARPi-sensitive, BRCA1-deficient UWB1.289 (UWB) cells compared to PARPi-insensitive, BRCA1-reconstituted UWB1.289 (UWB+B) cells. Global phosphoproteomics and ADP-ribosylation proteomics furthermore revealed that rucaparib induced the cell cycle pathway and NHEJ pathway in UWB cells, but down-regulated ErbB signaling in UWB+B cells. In addition, we observed AKT PARylation and pro-survival AKT-mTOR signaling in UWB+B cells after PARPi treatment. Consistently, synergy of PARPis with DNAPK or AKT inhibitors was more pronounced in UWB+B cells identifying these pathways as actionable vulnerabilities. In conclusion, the combination of chemical proteomics, phosphoproteomics and ADP-ribosylation proteomics can identify differential PARP1/2 complexes and diverse, but actionable drug compensatory signaling in OC.

INSTRUMENT(S): Q Exactive

ORGANISM(S): Homo Sapiens (human)

TISSUE(S): Ovarian Surface Epithelial Cell

DISEASE(S): Malignant Neoplasm Of Ovary

SUBMITTER: John Koomen  

LAB HEAD: Uwe Rix

PROVIDER: PXD029432 | Pride | 2022-10-21

REPOSITORIES: Pride