Targeting PRMT1 Reduces Cancer Persistence and Tumor Relapse in EGFR- and KRAS-Mutant Lung Cancer.

abstractIncomplete killing of cancer cells undermines oncogene-targeting therapies and drives disease relapse. Eliminating cancer cells that persist during treatment is crucial for improving treatment outcomes. Here, we discovered that a specific isoform of type I protein arginine methyltransferases (PRMT), namely, PRMT1, enables lung cancer cells with EGFR or KRASG12C driver mutations and high STAT1 activity to persist through targeted drug treatments. PRMT1 knockdown, combined with EGFR or KRASG12C inhibitors, decreased persistence and delayed cancer cell regrowth across cell line models and significantly prolonged tumor regression in xenograft models. In contrast, we found that knockdown of two other type I PRMT isoforms, PRMT4 and PRMT6, increased persistence. Finally, we found that targeting PRMT1 to reduce persistence is more effective in lung cancer models with intact versus deleted chromosome 5q31.1, a region enriched with JAK-STAT pathway genes, suggesting a potential stratification criterion. Together, our study pinpoints the PRMT1 isoform as a critical vulnerability of cancer persistence in EGFR- or KRASG12C-targeted therapies. SIGNIFICANCE: Eliminating "persisters" before relapse is crucial for achieving durable treatment efficacy. This study provides a rationale for developing PRMT1-selective inhibitors to target cancer persisters and achieve more durable outcomes in oncogene-targeting therapies.