MDR1和GST-π在骨软组织肉瘤中的表达及其与化疗耐药的关系

目的 探讨多药耐药基因1（MDR1）和谷胱苷肽-S-转移酶-π（GST-π）在骨软组织肉瘤组织中的表达及其与化疗耐药的关系。方法应用荧光定量PCR（FQ-PCR）和流式细胞术（FCM）,分别在mRNA水平和蛋白水平检测MDR1和GST-π的表达;以四甲基偶氮唑盐法（MTT）法检测瘤组织对阿霉素（ADM）、顺铂（DDP）、5-氟脲嘧啶（5-Fu）、丝裂霉素C（MMC）、氮烯咪胺（DTIC）、长春新碱（VCR）和氨甲喋呤（MTX）的敏感性。结果 患者瘤组织对ADM、DDP、5-Fu、MMC、lyric、VCR和MTX的不敏感率分别为41．18％、17．65％、47．06％、50．00％、76．47％、61．76％和52．94％。瘤组织中P-gp和GST-π相对荧光强度的表达分别为1．54和为2．58。X^2分析显示,P-gp的表达与ADM耐药、GST-π的表达与ADM、DDP、MMC耐药均呈正相关（P〈0．05）。MDR1和GST-π的表达与患者年龄、性别、病理类型、肿瘤大小均无关（P〉0．05）。GST-π在术前化疗患者的瘤组织中表达升高,且术前表达升高者,术后复发率高于术前GST-π表达水平较低者（P〈0．05）。结论 骨软组织肉瘤患者的MDR1、GST-π表达及化疗敏感性存在个体差异;化疗引起GST-π表达上调;原发GST-π高表达是骨软组织肉瘤耐药的主要机制,并与患者预后不良有关。

Expression of MDR1 and GST-pi in osteosarcoma and soft tissue sarcoma and their correlation with chemotherapy resistance

OBJECTIVE: To explore the expression of multidrug resistance gene 1 ( MDR1), glutathione-S-transferases-pi (GST-pi) in osteosarcoma and soft tissue sarcoma tissues from 34 patients and their correlation with chemotherapy resistance. METHODS: MDR1 and GST-pi expressions were analyzed by real-time fluorescence quantitative polymerase chain reaction (FQ-PCR) and flow cytometry (FCM) at mRNA and protein levels, respectively. Chemotherapy sensitivity on adriamycin, cisplatinum, fluorouracil, mitomycin C, dacarbazine, vincristine, methotrexate in tumor tissues were detected by MTT assay. RESULTS: The nonsensitive rates on adriamycin, cisplatinum, fluorouracil, mitomycin C, dacarbazine, vincristine, methotrexate in tumor tissues were 41.18%, 17.7%, 47.1%, 50.0%, 76.5%, 61.8% and 52.9%, respectively. The expression of P-glycoprotein (P-gp) and GST-pi in tumor tissues was 1.54 and 2.58 (relative fluorescence intensity). Chi2 analysis showed that there was a positive correlation between P-gp expression and drug resistance on ADM, GST-pi expression and resistance on ADM, DDP and MMC (P < 0.05). There was not seen obvious correlation between expression of MDR1, GST-pi and age, gender, pathological type, tumor size in osteosarcoma and soft tissue sarcoma patients (P > 0.05). The expression of GST-pi was increased in patients receiving preoperative chemotherapy. The rate of postoperative recurrence was higher in patients with higher GST-pi expression level than those with lower GST-pi expression level before operation (P < 0.05). CONCLUSION: Individual differences exist in chemotherapy sensitivity and expression of MDR1 and GST-pi in osteosarcoma and soft tissue sarcomas patients. Chemotherapy can induce up-regulation of GST-pi protein expression. Primary high expression of GST-pi is the main mechanism of resistance of osteosarcoma and soft tissue sarcomas to chemotherapy and is related to poor prognosis.