C-IGF1R encoded by cIGF1R acts as a molecular switch to restrict mitophagy of drug-tolerant persister tumour cells in non-small cell lung cancer.

The clinical efficacy of Epidermal Growth Factor Receptor Tyrosine Kinase Inhibitors (EGFR-TKIs) is limited by the emergence of drug resistance. We hypothesise that restoring dysregulated circular RNAs under initial treatment with EGFR-TKIs may enhance their effectiveness. Through high-throughput screening, we identify that combining circular RNA IGF1R (cIGF1R) with EGFR-TKIs significantly synergises to suppress tumour regrowth following drug withdrawal. Mechanistically, cIGF1R interacts with RNA helicase A (RHA) to depress insulin-like growth factor 1 receptor (IGF1R) mRNA splicing, negatively regulating the parent IGF1R signalling pathway. This regulation is similar to that of IGF1R inhibitor, which induces drug-tolerant persister (DTP) state with activated mitophagy. The cIGF1R also encodes a peptide C-IGF1R that reduces Parkin-mediated ubiquitination of voltage-dependent anion channel 1 (VDAC1) to restrict mitophagy, acting as a molecular switch that promotes the transition of DTP to apoptosis. Our study shows that combining cIGF1R with EGFR-TKIs efficiently reduces the emergence of DTP.