Uncovering synthetic lethal interactions for therapeutic targets and predictive markers in lung adenocarcinoma

Area of Science:

• Genomics
• Cancer Biology
• Therapeutics

Background:

• Synthetic lethality (SL) describes gene pairs where simultaneous mutation causes cell death, unlike individual mutations.
• Targeting SL partners of mutated cancer genes offers selective cancer cell killing with minimal impact on normal cells.
• Lung adenocarcinoma (LADC) presents a critical need for novel therapeutic strategies, especially given common TP53 mutations.

Purpose of the Study:

• To identify and validate novel synthetic lethal gene pairs as therapeutic targets for lung adenocarcinoma (LADC).
• To explore the therapeutic potential of targeting SL interactions, particularly PARP1-TP53, in LADC.
• To identify prognostic and predictive biomarkers for LADC patient stratification.

Main Methods:

• Integrated computational analysis to predict SL gene pairs.
• RNAi knockdown and synergistic toxicity assays in LADC cell lines (H1975, CL1-5).
• Immunohistochemistry (IHC) and gene expression analysis (including TCGA cohort) for prognostic and predictive marker validation.

Main Results:

• Identified 24 predicted SL pairs, with PARP1-TP53 validated for synergistic toxicity in LADC cells.
• Validated literature-consistent SL pairs: FEN1-RAD54B, BRCA1-TP53, BRCA2-TP53, RB1-TP53.
• Demonstrated that PARP1 silencing enhances carboplatin-induced cell death in LADC cells.
• Identified RAD54B, FEN1-RAD54B, PARP1-RAD54B, and POLB-TP53 as prognostic/predictive markers in Asian and TCGA LADC cohorts.

Conclusions:

• The PARP1-TP53 synthetic lethal interaction presents a promising therapeutic strategy for LADC, especially in TP53-mutated cases.
• PARP1 inhibition may sensitize LADC cells to platinum-based chemotherapy.
• POLB and POLB-TP53 serve as potential predictive biomarkers for stratifying LADC patients for targeted therapies.