The Role Of JNK Signaling Pathway In Chemoresistance Of Hypopharyngeal Carcinoma FaDu Cells

ObjectiveThe causes of death in patients with advanced hypopharyngeal cancer can be attributed to the following:1.Local recurrence;2.Distant metastasis;3.Radiochemotherapy resistance.As far as chemotherapy is concerned,TPF is commonly used in clinic,including docetaxel,DDP,5-fluorouracil(5-FU).The main purpose of this study is to compare the malignant biological characteristics of FaDu and FaDu/T cells,detect the expression of drug resistance and apoptosis-related proteins in FaDu and FaDu/T cell lines,and reverse the malignant biological characteristics of hypopharyngeal carcinoma by proteasome inhibitor MG-132.To investigate the role of JNK signal transduction pathway and NF-kappa B in the reversal of P-gp expression in FaDu/T cells of hypopharyngeal carcinoma by MG-132,and to lay a theoretical foundation for further reversal of chemotherapeutic resistance and other malignant biological characteristics of hypopharyngeal carcinoma cells.MethodsPaclitaxel-resistant human hypopharyngeal carcinoma cell line FaDu/T was successfully established by concentration gradient increment method.On this basis,different expressions of P-gp,Bcl-2,Bax and caspase-3 proteins related to chemotherapy resistance and apoptosis were detected.By comparison,FaDu/T cells were found to be comparable to FaDu cells.The expression of multidrug resistance gene and protein P-gp,apoptosis-related protein Bcl-2,Bax and Caspase-3 in the two cell lines were detected by reverse transcription-polymerase chain reaction(RT-PCR)and Western blotting respectively;The multidrug resistance sensitivities of FaDu,FaDu/T and FaDu/T+MG-132 cells to 5-FU,DDP,DOX,VCR were investigated by Methyl-Thiazolyl-Tetrazolium(MTT)assay.Proteasome inhibitor MG-132 was used to reverse the above-mentioned malignant biological behavior of hypopharyngeal carcinoma FaDu/T,the expression of JNK signal transduction pathway related proteins and NF-kappa B nuclear transcription proteins were detected by flow cytometry and Western blotting.Results1.The tolerance of FaDu cells to paclitaxel cell line FaDu/T was successfully established.FaDu/T has stronger malignant biological characteristics than FaDu cells.2.Compared with FaDu cells,the expression of multidrug resistance protein P-gp and anti-apoptotic protein Bcl-2 in FaDu/T cells increased significantly,but the expression of apoptosis-related proteins Bax and caspase-3 decreased.3.MG-132 can significantly reverse the malignant biological behavior of FaDu/T such as multidrug resistance and anti apoptosis.4.The JNK signal transduction pathway was activated after paclitaxel was initially acted on FaDu cells,but the JNK signal transduction pathway was partially inactivated in FaDu/T cells,but the nuclear transcription protein NF-kappa B transcription activity was continuously enhanced.Proteasome inhibitor MG-132 can reactivate the JNK signaling pathway of FaDu/T cells.The nuclear transcriptional activity of NF-kappa B was significantly inhibited.5.There was no significant change in P-gp expression after the addition of JNK specific inhibitor SP600125 to the drug-resistant cell line FaDu/T,suggesting that JNK signaling pathway and NF-kappa B plays an important role in the regulation of chemotherapy resistance in hypopharyngeal carcinoma.Conclusions1.FaDu/T has stronger malignant biological characteristics.2.Proteasome inhibitor MG-132 can effectively reverse this malignant biological behavior.3.JNK signal transduction pathway and NF-kappa B participate in the reversal process of MG-132 on malignant biological behavior of hypopharyngeal carcinoma.