The Role And Mechanism Of Interleukin 25 In Cisplatin Resistance Of Lung Adenocarcinoma

Lung cancer is a malignant tumor that grows in the trachea,bronchi,bronchioles,including alveolar tissue.It is currently the world's highest incidence and highest mortality.Chemotherapy is one of the main treatments for lung cancer.More than 90% of lung cancers require chemotherapy.Among them,platinum-based chemotherapy has always been the first choice for clinical use.However,lung cancer tolerance after chemotherapy is a clinical problem to be solved.Multidrug resistance(MDR)of lung cancer refers to the phenomenon that lung cancer cells are cross-resistance to various chemotherapeutic drugs and it is also an important reason for the failure of tumor chemotherapy.MDR could be divided into two types: innate and acquired.Innate resistance is generally the ability of certain cancers and it is associated with genes;Acquired resistance refers to the resistance of cancer acquired after drug treatment.It is related to many factors,such as: MRP,P53,glutathione transferase,abnormal apoptosis,and so on.The major Vaulit protein(MVP),also known as lung resistance-related protein(LRP),plays an important role in tumor acquired resistance.It is one of the major constituent proteins of the Vault and mainly mediates nuclear membrane transport function.It is one of the important factors for tumor cells tolerate platinum drugs.IL-25,also known as IL-17 E,is a member of the IL-17 family and has unique functions in regulating allergies and Th2-type responses.The main sources of IL-25 have been found to include epithelial cells,myeloid cells,eosinophils,basophils,and mast cells.It can induce some lymphocytes to secrete Th2 type cytokines and promote Th2-type responses.In addition,it plays an important role in aller gic lung disease and host defense against parasites.In recent years,studies have shown that IL-25 plays an important role in tumor therapy,but its relationship with multidrug resistance of lung cancer has not been studied.In this paper,we found that IL-25 has a certain relationship with cisplatin resistance in lung adenocarcinoma cells,and has done some research on its mechanism.The specific results are as follows: 1.There is a significant difference between A549 and A549/CDDP.In order to explore the chemoresistance mechanism of lung adenocarcinoma cells,we successfully constructed A549 cisplatin-resistant cell A549/CDDP.Although they are the lung adenocarcinoma cell line,there are significant differences between them.In terms of morphology,resistant cell generally exhibits a spindle-like structure,similar to fibroblasts,compared to the irregular pattern of the parent cell.In addition,the drug-resistant cell has stronger invasive ability than the parent cell,and can survive at a higher concentration of cisplatin,and the expression of the drug-related protein MVP is also significantly increased.2.IL-25 is abnormally expressed in drug-resistant cell and participates in the formation of cisplatin resistance Since IL-25 is a secreted protein,we examined the intracellular and extracellular expression of IL-25 in A549 and A549/CDDP respectively.The results showed that the expression level of IL-25 in drug-resistance cell was higher than that in the parental cell.Subsequently,We overexpressed IL-25 in parental cell and silenced IL-25 in drug-resistant cell and found that overexpression of IL-25 enhanced the cisplatin resistance of A549,while silence of IL-25 reduced the tolerance of A549/CDDP.These phenomenon suggested that IL-25 was involved in cisplatin resistance in lung adenocarcinoma cells,and its expression increaseed cisplatin resistance in lung adenocarcinoma cell line A549.3.IL-25 mediates MVP expression by activating NF-?B pathwayTo further explore the mechanism by which IL-25 enhanced cisplatin resistance in lung adenocarcinoma cell line A549,we examined the expression of MVP in IL-25 overexpression group and IL-25 silence group.As a result,it was found that the overexpression group exhibited a higher level of MVP expression,while the silence group exhibited a lower level of MVP expression.In addition,the expression of MVP also showed a trend change in A549 cells stimulated with different concentrations of IL-25.These results indicated that IL-25 regulates the expression of MVP.Subsequently,we examined the activation of the NF-?B signaling pathway in the IL-25 overexpression group and IL-25 silence group,respectively.The results indicated that overexpression or silence of IL-25 led to activation or inhibition of the NF-?B signaling pathway.In addition,the NF-?B signaling pathway was also activated by exo genous IL-25 stimulation of A549,and the gradient was increased with the addition of IL-25.Further experiments showed that QNZ,a NF-?B signaling pathway blocker,inhibits exogenous IL-25-induced MVP expression upregulation in A549 cells.These indicated that IL-25 regulated the expression of MVP by activating the NF-?B signaling pathway,and IL-25 could not enhance the MVP expression if we interfered with the NF-?B pathway.4.IL-25 is resistant to cisplatin in the tumor-bearing model of nude miceVitro experiments showed that IL-25 could help lung adenocarcinoma A549 resist cisplatin and continue to survive.In order to explore whether IL-25 had the same effect in vivo,we established a tumor-bearing mouse model,which was treated with cisplatin,cisplatin mixed with IL-25 solution,and observed the growth of tumor in mice.The results indicated that the presence of IL-25 interfered with the efficacy of cisplatin in the treatment of tumors.And histological analysis found that the tumor tissues of the IL-25 group expressed MVP highly.These indicated that IL-25 also played a role in assisting tumor escape chemotherapy in vivo.