Induced Degradation of Lineage-specific Oncoproteins Underlies the Selective PARP1 Inhibitor Toxicity in Small Cell Lung Cancer (batch2-6)

ABSTRACT: A subset of small cell lung cancer (SCLC) shows a clinical response to PARP inhibitors (PARPi) despite being proficient in homologous repair pathways. However, the underlying mechanism(s) of PARPi sensitivity is poorly understood. We performed quantitative proteomic analyses and identified proteomic changes that signify PARPi responses in a large panel of molecularly annotated patient-derived SCLC lines. We found that the toxicity of PARPi in SCLC is explained by the PARPi-induced degradation of key lineage-specific oncoproteins including ASCL1, NEUROD1, POU2F3, KDM4A, and KDM5B. Biochemical experiments showed that PARPi-induced activation of E3 ligases (e.g., HUWE1 and RNF8) mediated the ubiquitin-proteasome system (UPS)-dependent degradation of these oncoproteins. Interestingly, although PARPi resulted in a general DNA damage response, this signal is sensed by different SCLC cell lines to generate a cell-specific response. The dissection of the cell-specific oncoprotein degradation response led to the identification of potentially predictive biomarkers for PARPi in SCLC. The combination of PARPi and agents targeting these pathways led to dramatically improved cytotoxicity in SCLC. PARPi-induced degradation of lineage-specific oncoproteins therefore represents a novel mechanism to explain the efficacy of PARPi in tumors without homologous recombination deficiency.

INSTRUMENT(S): Orbitrap Eclipse

ORGANISM(S): Homo Sapiens (human)

SUBMITTER: Xu-Dong Wang  

LAB HEAD: Yonghao Yu

PROVIDER: PXD029968 | Pride | 2024-01-26

REPOSITORIES: Pride