EREG increases stemness associated genes expression and promotes Chemoresistance of non-small cell lung cancer via ERK signaling

Abstract Background: Chemotherapy is the preferred approach for treatment of advanced non-small cell lung cancer (NSCLC), but it often resulted in acquired resistance, which led to the failure of treatment. Therefore, it is necessary to identify and remove the resistant cancer cells in the tumors with acquired resistance. Thus far, there is no comprehensive analysis of RNA-Seq data from lung cancer patients and none of the available enriched signaling could act as a therapeutic target to re-sensitize the acquired resistant cancer cells to chemo-drugs. Hence, in this study, we aimed to identify the resistance signature for clinical lung cancer patients and explore the regulation mechanism.Method: Analysis of RNA-Seq data from clinical lung cancer patients was conducted in R studio to identify the resistance signature of resistant NSCLC. The resistance signature was validated by survival time of lung cancer patients and qPCR in cisplatin and taxol resistant cells. Cytokine application, Lentivirus-based small-interfering RNA and pharmacological inhibition approaches were applied to characterize the function and molecular mechanism of EREG and downstream signaling in chemoresistance regulation via stemness by western blot, qPCR, cell viability and spheres assays in NSCLC.Results: Thirty-two differentially expressed genes in the treated patients were identified as the resistant genes. The RTK and vitamin D signaling were enriched among resistance genes, where 6 genes were validated as resistance signature and proven to be associated with poor survival in patients. EREG was highly expressed in lung cancer patients and associated with survival time of lung cancer patients. EREG protein promoted the NSCLC resistant to chemo-drug by increasing stemness genes expression. Additionally, inhibition of EREG/ErbB had downregulated ERK signaling, resulted in decreased expression of stemness associated genes and subsequently re-sensitized the resistant NSCLC cells and spheres to chemo-drugs. Conclusions: These findings revealed 6 resistance genes signature and proved that EREG/ErbB regulated the stemness to maintain chemoresistance of NSCLC via ERK signaling. Therefore, targeting EREG/ErbB might significantly and effectively resolve the chemoresistance issue.