Abstract 383: Mic19 regulates mitophagy in non-small cell lung cancer under hypoxic microenvironment

Abstract Background: Mitophagy is a pivotal cellular process crucial for maintaining homeostasis in hypoxic conditions, selectively eliminating dysfunctional mitochondria through autophagy. This process is implicated in various diseases, including cancer. Non-Small Cell Lung Cancer (NSCLC), known for its prevalence and aggressiveness, often encounters hypoxic microenvironments. Mic19, a core protein of the mitochondrial cristae membrane, plays vital roles in maintaining mitochondrial architecture and function. However, its involvement in mitophagy in hypoxic NSCLC and the underlying molecular mechanisms remain inadequately explored. Methods: NSCLC cells were cultured under conditions with 1% O2 oxygen concentration to simulate a hypoxic microenvironment. Protein expression levels of Mic19 were analyzed using Western Blot and immunofluorescence (IF). Cellular proliferation and metastasis capability were assessed through CCK8 and transwell experiments. Immunoprecipitation experiments were conducted to validate the interaction between Mic19 and key mitophagy regulatory proteins. IF, confocal microscopy, ATP measurement, oxygen consumption rate (OCR), mitochondrial membrane potential, and transmission electron microscopy were employed to assess the formation of mitochondrial cristae and the level of mitophagy. Results: In hypoxic conditions, Mic19 exhibited up-regulation in NSCLC cells. Subsequent in vitro experiments confirmed Mic19's pivotal role in promoting the growth and metastasis of lung cancer cell lines. Through clinical data analysis, Mic19 emerged as an independent prognostic indicator for NSCLC. Inhibition of Mic19 expression exacerbated the disruption of mitochondrial morphology and structure in lung cancer cells, accompanied by the loss of mitochondrial cristae. Notably, Mic19 expression closely correlated with ATP and OCR production in tumor cells. Assessment of mitochondrial membrane potential and transmission electron microscopy revealed Mic19 as a critical downstream target of hypoxia, mediating mitophagy. Overall, these findings not only underscore the significance of Mic19 in regulating mitochondrial dynamics but also highlight its multifaceted role in tumor progression, positioning Mic19 as a promising therapeutic target and prognostic biomarker for NSCLC. Conclusion: This study provides novel insights into the mechanistic understanding of hypoxia-induced mitophagy in NSCLC, emphasizing the regulatory role of Mic19. Mic19 emerges as a potential therapeutic target for future interventions in NSCLC patients. Citation Format: Hua Huang, Chen Ding, Zhanrui Zhang, Di Wu, Chen Chen, Yongwen Li, Hongyu Liu, Jun Chen. Mic19 regulates mitophagy in non-small cell lung cancer under hypoxic microenvironment [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 383.