Transcriptional Activation Of Gstp1 By MEK/ERK Signaling Confers Chemoresistance To Cisplatin In Lung Cancer Stem Cells

Objective:To investigate the molecular mechanism of Gstp1regulating the resistance to cisplatin in lung cancer stem cells.Methods:?1?The resistance of LLC-Parental and LLC-SD cells were detected in three different types of chemotherapy drug using CCK-8 and Flow cytometry Apoptosis assay.?2?The stable cell lines of Gstp1silencing and overexpression in LLC-SD cells were constructed,and the resistance of Gstp1 to cisplatin in mouse and human lung cancer stem cells was verified by experiments in vitro and in vivo.?3?The stable cell lines of Mek1/2 silencing and overexpression in LLC-SD cells were constructed,and the resistance of MEK/ERK signaling pathway to cisplatin in mouse and human lung cancer stem cells was verified by experiments in vitro and in vivo.?4?After overexpression of Gstp1,the relationship between MEK/ERK signaling pathway and Gstp1 regulated drug resistance was verified.?5?To assess the clinical relevance of Gstp1 in lung adenocarcinoma,lung adenocarcinoma mRNA sequencing datasets from cancer database and expression of Gstp1 of clinical samples of lung adenocarcinoma were analyzed.Results:?1?The IC₅₀ assay results revealed that LLC-SD exhibited12.8-fold,30.0-fold and 50.6-fold resistance to cisplatin,paclitaxel and 5-fluorouracil respectively,compared with their parental chemosensitive counterparts.?2?Compared with the control group,the IC₅₀ to cisplatin decreased or increased after knockdown or overexpressing Gstp1 in LLC-SD cells,and the tumor formation decreased or increased after cisplatin treatment in vivo,respectively.?3?Compared with the control group,the IC₅₀ to cisplatin decreased after knockdown Mek1/2 in LLC-SD cells,and the tumor formation decreased after cisplatin treatment in vivo.?4?Overexpression of Gstp1 reversed the suppression function of Mek1/2signaling pathway.?5?Gstp1 was dramatically elevated in lung adenocarcinoma tissues compared with the normal tissues and was higher in advanced lung adenocarcinoma.High Gstp1 mRNA levels are linked with disease progression and lower survival.Conclusion:?1?Cancer stem cell component of lung adenocarcinoma is the source that confers multidrug resistance phenotype.?2?Gstp1 confers cisplatin resistance in lung CSC models,both in vitro and in vivo.?3?Transcriptional activation of Gstp1 expression by MEK/ERK signaling underlies cisplatin resistance in lung CSC cells.?4?Gstp1 expression is a good diagnostic and prognostic marker for human lung adenocarcinoma thus is of high clinical relevance.