Chloroquine induces transitory attenuation of proliferation of human lung cancer cells through regulation of mutant P53 and YAP
Heena Saini, Mahima Choudhary, Harshita Sharma, Shibasish Chowdhury, Sudeshna Mukherjee & Rajdeep Chowdhury
In this study, we identify key molecular factors de-regulated in NSCLCs. Analyze their expression by real-time PCR and immunoblot; map their localization by immuno-fluorescence microscopy. We further propose an FDA approved drug, chloroquine (CQ) that affects the function of the molecular factors and hence can be repurposed as a therapeutic strategy against NSCLCs. Available NSCLC mutation data reflects a high probabilistic chance of patients harboring a p53 mutation, especially a gain of function (GOF)-R273H mutation. The GOF-P53 mutation enables the P53 protein to potentially interact with non-canonical protein partners facilitating oncogenesis. In this context, analysis of existing transcriptomic data from R273H-P53 expressing cells shows a concomitant up-regulation of Yes-associated protein (YAP) transcriptional targets and its protein partner TEAD1 in NSCLCs, suggesting a possible link between R273H-P53 and YAP. We therefore explored the inter-dependence of R273H-P53 and YAP in NSCLC cells. They were found to co-operatively regulate NSCLC proliferation. Genetic or pharmacological inhibition of YAP and GOF-P53 resulted in sensitization of NSCLC cells. Further analysis of pathways controlled by GOF-P53 and YAP showed that they positively regulate the cellular homeostatic process- autophagy to mediate survival. We hence postulated that a modulation of autophagy might be a potent strategy to curb proliferation. In accordance to above, autophagy inhibition, especially with the FDA-approved drug- chloroquine (CQ) resulted in cytoplasmic accumulation and reduced transcriptional activity of GOF-P53 and YAP, leading to growth arrest of NSCLC cells.