MCAM mediates chemoresistance in small cell lung cancer via the PI3K/AKT/SOX2 signaling pathway
Menée à l'aide de lignées cellulaires de cancer du poumon à petites cellules et de xénogreffes dérivées de patients, cette étude montre que la protéine de surface MCAM induit la chimiorésistance des cellules tumorales via un mécanisme impliquant la voie de signalisation PI3K/AKT/SOX2
Despite favorable responses to initial therapy, small cell lung cancer (SCLC) relapse occurs within a year and exhibits resistance to multiple drugs. Due to limited accessibility of patient tissues for research purposes, SCLC-patient derived xenografts (PDX) have provided the best opportunity to address this limitation. Here we sought to identify novel mechanisms involved in SCLC chemoresistance. Through in-depth proteomic profiling, we identified MCAM as a markedly upregulated surface receptor in chemoresistant SCLC cell lines and in chemoresistant PDX compared to matched treatment-naïve tumors. MCAM depletion in chemoresistant cells reduced cell proliferation and reduced the IC50 inhibitory concentration of chemotherapeutic drugs in vitro. This MCAM-mediated sensitization to chemotherapy occurred via SOX2-dependent upregulation of mitochondrial 37S ribosomal protein 1/ATP binding cassette subfamily C member 1 (MRP1/ABCC1) and the PI3/AKT pathway. Metabolomic profiling revealed that MCAM modulated lactate production in chemoresistant cells that exhibit a distinct metabolic phenotype characterized by low oxidative phosphorylation. Our results suggest that MCAM may serve as a novel therapeutic target to overcome chemoresistance in SCLC.