Research On The Expression Of Musashi-2 In Non-small Cell Lung Cancers And Its Role In Tumor Function

Lung cancer is currently the leading cause of cancer-related deaths in the world.The main pathological type is non-small cell lung cancer(NSCLC).The treatment of NSCLC includes surgical treatment,radiotherapy and chemotherapy,targeted therapy and immunotherapy.Despite the fast development of medical treatment,the overall survival of NSCLC is still not satisfactory,and the 5-year survival rate is about 16%.RNA Binding Proteins(RBPs)play a key role in gene regulation.The Musashi(MSI)family is a class of evolutionarily conserved RNA-binding proteins.Musashi-2(MSI2),which belongs to the MSI family,is found to be a regulator of many key biological processes such as cancer development,progression and drug resistance.It is overexpressed in many cancer types and is associated with prognosis.However,there are still few studies on MSI2 in NSCLC.This study is divided into three parts,we studied the expression of MSI2 gene in different types of NSCLC and its effect on tumor function to further enrich the cell function of MSI2,providing theoretical basis to support MSI2 as a potential new target in the prognosis and treatment of NSCLC.In the first part,we used immunohistochemistry to analyze the tumor tissues of different types of NSCLC,and selected a variety of different types of NSCLC cell lines to detect the expression level of MSI2 by western blot.Combined with public databases,we found that abnormal and different expression of MSI2 is present in the NSCLC with different pathological types.In the second part,stable MSI2 overexpression models of A549,H460,PC-9,H226 cell lines and A549,PC-9 stable MSI2 knockdown cell lines were successfully established by lentivirus,which were verified by RT-qPCR and western blot.In the third part,we used the established overexpression and knockdown cell models to study the effects of MSI2 on cell proliferation,invasion,metastasis and colony formation in different types of NSCLC,and we found that MSI2 plays a different role in PC-9,an EGFR-mutated NSCLC cell line,from other types of cells.Next,we used A549 and PC-9 cells for drug sensitivity experiments and found that MSI2 overexpression in A549 reduced its sensitivity to the chemotherapeutic drugs cisplatin and pemetrexed;whereas in PC-9,MSI2 overexpression will increase its sensitivity to the chemotherapeutic drugs cisplatin and pemetrexed,as well as the targeted drug gefitinib.In addition,we performed deep RNA sequencing of the overexpression group of four cells,including mRNA and lncRNA,and we also performed immunoprecipitation experiments and mass spectrometry with overexpression group of four cells.RNA sequencing and mass spectrometry results will further explore the potential upstream and downstream pathways of MSI2.Therefore,our results suggest that MSI2 is abnormally highly expressed in different types of NSCLC.The change of MSI2 expression level may affect the function and drug sensitivity of tumor cells,and the function of MSI2 in tumor may be related to the EGFR genotype of NSCLC.