Research Of Y-320's Reversal For Multidrug Resistance Tumor Cells And Its Mechanism

BackgroundMalignant tumor is one of the crucial factors that affecting human health.And chemotherapy is one of the significant ways of clinical tumor treatment at present.However,at present,there has been more and more problems of traditional chemotherapy such as tumor drug resistance and serious side effects.The overexpression of P-glycolprotein?P-gp?and its efficient drug pump function are the main causes of drug resistance in various malignant tumor cell lines.And the severe side effects are mostly caused by the use of large doses of chemotherapy agents.These conditions seriously restrict the development of chemotherapy in clinical and has become one of the public health problems to be solved urgently.So,how to enhance the effectiveness and reduce the side effects of clinical chemotherapy agents is the key to promote the development of clinical chemotherapy research.It is particularly important to find effective and low toxic inhibitors for P-gp and sensitizers for chemotherapy.Y-320,a novel immune-modulator and phenylpyrazolamide compound,inhibits interleukin 17?IL-17?biosynthesis by CD4⁺T cells stimulated with interleukin 15?IL-15?in body.As we all know,IL-17,a significant inflammatory cytokine,participates in a variety of inflammatory reactions and plays a significant role in the pathogenesis of various autoimmune diseases.At the same time,IL-17 is also involved in the development,metastasis,invasion and development of drug resistance in various malignant tumor cell lines.Recently,many immunomodulators of IL-17 have been reported to have favourable effect and low toxicity on the treatment of tumors.These immunomodulators can cause remarkable damage to tumor cells as monotherapy or combined with other chemotherapeutic or targeted agents.Y-320'efficient and safe use in autoimmune diseases such as rheumatoid arthritis and collagen-induced arthritis has been documented.However,no studies have established its oncological application either as monotherapy or combined other chemotherapy or targeted agents.ObjectiveTo explore the efficacy of Y-320 combined with paclitaxel?PTX?,vinorelbine?VBN?,doxorubicin?DOX?and other chemotherapy agents in the treatment of multidrug resistance?MDR?tumor cells in vitro,and clarify the molecular mechanism of Y-320 reversing multidrug resistance.MethodsThe efficacy of Y-320 and paclitaxel,vinorelbine,doxorubicin and other chemotherapy drugs in the treatment of multidrug resistant tumor cells was preliminarily determined in vitro,and IC₅₀was calculated by methyl thiazolyl tetrazolium?MTT?.And investigating the effect of Y-320 combined with paclitaxel on cell cycle and apoptosis of drug-resistant tumor cells.On this basis,the effect of Y-320for P-gp expression and function was detected to explore the mechanism of reversing drug resistance.Xenograft experiments were divided into blank control group,paclitaxel monotherapy group,Y-320 monotherapy group and paclitaxel+Y-320 group to test the efficacy and safety in vivo treatment.ResultsThis study demonstrated that while low dose Y-320?500 n M?had little effect on hepatocellular carcinoma and breast cancer MDR cell lines,it induced remarkable injury to MDR tumor cells when concurrently administered with paclitaxel.Y-320reduced the IC₅₀of the breast cancer cell line Bads-200 of PTX from 1148.1 n M to208.3 n M,reduced the IC₅₀of Bats-72 of PTX from 152.8 n M to 16.2 n M and reduced the IC₅₀of the hepatocellular carcinoma cell line Huh7-TS-48 of PTX from 858.5 n M to514.5 n M.Similar results were obtained in VBN and DOX test.The results showed that this co-administration mode reduced the IC₅₀of MDR tumor cells to various chemotherapy drugs and caused significant damaging effect to these cells.Compared to a low dose?500 n M?of paclitaxel monotherapy,co-treatment of Y-320 with PTX significantly increased expression of proteins related to cycle arrest and apoptosis and thus induced G2/M phase arrest?the arrest rate increased from 6.3%to 42.5%,p<0.01?and apoptosis?the apoptosis rate increased from 2.2%to 30.8%,p<0.01?.Further analyses indicated that Y-320 was a substrate of P-gp.It could inhibit P-gp efflux function by binding to P-gp specifically without altering P-gp expression,thus subsequently increase the intracellular concentration of chemotherapeutic agents and reverse P-gp mediated drug resistance in MDR tumor cells.The co-administration with Y-320 and paclitaxel suppressed tumor growth remarkably with an inhibition rate of77.1%compared to 6.5%in the paclitaxel monotherapy group in vivo.The positive rate of Ki-67 was significantly reduced in Ki-67 stain in the co-treatment group,which also confirmed that the co-treatment could cause significant apoptosis in tumor tissues.At the same time,no significant changes in body weight and hepatorenal serology were observed in co-treatment group compared with control group which confirmed this co-administration did not increase extra complications in nude mice MDR tumor xenograft models.ConclusionsThe results showed that Y-320 could reverse the multidrug resistance induced by P-gp through inhibiting P-gp activity.Combined use of Y-320 and paclitaxel or other chemotherapy agents can significantly damage multidrug resistant tumor cells without increasing toxicity in vivo.This combination may be appropriate for patients who do not respond to the maximum dose of chemotherapy drugs or cannot tolerate the associated systemic toxicity.In short,our results confirm that Y-320 could be approved for therapy of tumor as a novel P-gp inhibitor and chemotherapy sensitizer for the first time.The co-administration of Y-320 and chemotherapeutic agents might be an effective and low-toxicity chemotherapeutic regime for the MDR tumor patients.