| BackgroundNasopharyngeal carcinoma(NPC) is one of the most prevalent head and neck malignant tumors in south China. A majority of NPC are poorly differentiated, 95% is poorly differentiated squamous cell carcinomas, high degree of malignant degree is higher, which is deeply threatened the life and health of human beings. At present, the clinical treatment of NPC is mainly composed of radiotherapy and chemotherapy. Cisplatin is a first-line drug for clinical chemotherapy of NPC, but which frequently induces resistance during chemotherapy, seriously affect the treatment effect and prognosis of NPC. Therefore, provening nasopharyngeal carcinoma cisplatin resistance mechanism, and improving the curative effect of the platinum drugs, is a hot spot in the treatment of NPC.The abnormal activation of Wnt/beta-catenin signaling pathway involved in NPC chemotherapy drug resistance. The stability of Beta-catenin within the cytoplasm plays a key role in the Wnt/beta-catenin signaling pathway activation. Beta-catenin exist abnormal expression in a variety of malignant tumors, but the rate of mutation probability is not high, so the abnormal activation of Wnt/beta-catenin signaling pathway may be caused by the gene mutations of the headwaters of the beta-catenin. Dishevelled(DVL) is a crucial positive adjustment factor of the headwaters of the beta-catenin. In the Wnt/beta-catenin signaling pathways, after activation of DVL can prompt beta-catenin accumulation during the cytoplasm and nuclear transfer, and then activate transcription factor TCF/LEF induced the expression of target genes. Study found that, the expression of DVL protein is higher in a variety of malignant tumors and participates in the malignant behavior. At present, the reports of the expression of the DVL family members and the resistance of NPC cells to cisplatin chemotherapy drug are rarely at home and abroad. ObjectiveVerify the effects of cisplatin on the expression of NPC cell DVL2 and DVL3; Prove the effect of DVL2 and DVL3 to cisplatin chemotherapy drug resistance on the NPC cells. In order to lay the foundation of further research the mechanism of DVL2 and DVL3 in the chemotherapy drug resistance of tumor and effective reverse drug-resistant of NPC. Methods1. Different concentration of cisplatin(0,4,8μmol/L) on NPC cells for 48 h, Western blotting detects the protein expression of DVL2 and DVL3 in NPC cells.2. Transfect pc DNA3.1-DVL2 and pc DNA3.1-DVL3 to NPC cells, then treated the cells with different concentration of cisplatin(0,1,2,4,8,10,20μmol/L), using MTT test the effect of overexpression of DVL2 and DVL3 to cisplatin inhibition rate of NPC cells and IC50.3. Transfect pc DNA3.1-DVL2 and pc DNA3.1-DVL3 to NPC cells, the treats cells with cisplatin(10μmol/L). Using flow cytometry assays to test the influence of overexpression of DVL2 and DVL3 to apoptosis of NPC cells.4. Transfect pc DNA3.1-DVL2, pc DNA3.1-DVL3, sh RNA-DVL2 and sh RNA-DVL3 to NPC cells, Western blotting detects the influence of overexpression and silence of DVL2 and DVL3 to the protein of P-gp、Survivin and β-catenin within NPC cells. Results1. Cisplatin chemotherapy induced DVL2, DVL3 protein expression in NPC cells, which was concentration-dependent.2. Overexpression of DVL3 and DVL2 reduced the inhibitory rate of cisplatin on NPC cells, and increased the IC50.3. Overexpression of DVL2 and DVL3 reduced the apoptosis of NPC cells which was induced by cisplatin.4. Overexpression and silence of DVL2 and DVL3 in NPC cells accordingly increased and decreased the expression of beta-catenin and its target gene, P-gp and Survivin protein. ConclusionThe protein expression of DVL2 and DVL3 in NPC cells was up-regulated by cisplatin.Overexpression of DVL2 and DVL3 enhanced the tolerance of NPC cells to cisplatin, suppressed the apoptosis which was induced by cisplatin; further research shows, DVL2 and DVL3 enhanced the expressions of P-gp and Survivin by raising the Wnt/beta-catenin, thus induced NPC cisplatin resistance. |
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