MRPL47 Deficiency Drives Mitochondrial Dysfunction via ROS/p38-MAPK/CDKN1A Signaling in Non-Small Cell Lung Cancer

Mitoribosomes play a pivotal role in cellular energy metabolism by synthesizing proteins involved in oxidative phosphorylation (OXPHOS) system. Dysregulation of mitoribosomes has been linked to Cancer, yet there have been no studies demonstrating the genetics and epigenetic landscape of mitoribosomal proteins (MRPs). In this study, we conducted a comprehensive analysis of expression, copy number variations, mutations, data from TCGA NSCLC patients to elucidate the genetic mechanism regulating MRPs in NSCLC. Consequently, we identified MRPL47, a significantly amplified and overexpressed mitoribosomal gene. We also found significant correlation of MRPL47 expression and copy number with patients’ survival. Functionally, we showed that inhibition of MRPL47 was associated with reduced cell proliferation and migration. Furthermore, silencing MRPL47 impaired the enzymatic activity of electron chain complex I & III leading to a defective OXPHOS system and elevated mitochondrial ROS level. Further, we showed ROS-mediated increase in CDKN1A through the p38 MAPK pathway. The increased CDKN1A level induced G1 cell cycle arrest by inhibiting E2F activity. RNA sequencing analysis further confirmed that MRPL47 hinders cell growth by inhibiting E2F pathway. Additionally, we found that MRPL47 selectively regulates mitochondrial translation of specific OXPHOS proteins rather than influencing all mitochondrial proteins. Altogether, these findings suggest that MARPL47, is amplified and overexpressed in NSCLC and plays a critical role in tumor progression by regulating ROS signaling pathways.