乳腺癌组织中黑色素瘤相关抗原C2的表达及其机制

Expression of melanoma-associated antigen-C2 in breast cancers and mechanism

目的探讨黑色素瘤相关抗原C2(MAGE-C2)在乳腺正常组织、良性病变组织和癌组织中的表达、表达机制及临床意义。方法分别采用逆转录聚合酶链反应(RT-PCR)和免疫组化法检测60例乳腺正常组织、60例乳腺良性病变组织和60例乳腺癌组织中MAGE-C2 mRNA和蛋白的表达,分析其与乳腺癌患者临床病理特征及预后的关系。以DNA甲基化酶抑制剂5-氮杂-2′-脱氧胞苷(5-aza-CdR)和组蛋白去乙酰化酶抑制剂曲古抑菌素A(TSA)干预人乳腺癌细胞MCF-7和MDA-MB-231后,采用RT-PCR法检测MAGE-C2 mRNA表达的变化。结果乳腺癌组织中MAGE-C2 mRNA阳性表达率为61.7%(37/60),MAGE-C2蛋白阳性表达率为58.3%(35/60),乳腺正常组织和良性病变组织中未见MAGE-C2 mRNA及蛋白的表达。MAGE-C2蛋白表达与乳腺癌的病理类型、组织学分级、脉管瘤栓有关(均P<0.05)。MAGE-C2蛋白表达阳性乳腺癌患者的无复发生存率低于MAGE-C2蛋白表达阴性的患者(χ^(2)=4.467,P=0.035)。多因素Cox回归分析显示,临床分期(HR=4.715,P=0.004)、淋巴结转移(HR=3.827,P=0.023)和MAGE-C2蛋白表达(HR=4.229,P=0.026)是乳腺癌患者无复发生存的独立影响因素。对照组和TSA组乳腺癌细胞中未见MAGE-C2 mRNA表达,5-aza-CdR组乳腺癌细胞中可见MAGE-C2 mRNA表达(MCF-7细胞为0.2914±0.0274,MDA-MB-231细胞为0.4808±0.0288),联合应用5-aza-CdR和TSA可使乳腺癌细胞中MAGE-C2 mRNA表达进一步增加(MCF-7细胞为1.0357±0.0644,MDA-MB-231细胞为1.6013±0.0675)。结论MAGE-C2是肿瘤特异性抗原,其表达与乳腺癌患者的不良预后有关,DNA甲基化和组蛋白乙酰化可能是调控MAGE-C2基因表达的重要机制。

Objective To analyze the expression pattern,mechanism and clinical significance of melanoma-associated antigen-C2(MAGE-C2)in tumor-free breast specimens,breast benign disease specimens and breast cancer specimens.Methods Reverse transcription-polymerase chain reaction(RT-PCR)and immunohistochemistry were used to investigate the expressions of MAGE-C2 in 60 tumor-free breast specimens,60 breast benign disease specimens and 60 breast cancer specimens.The correlation of MAGE-C2 expression with clinicopathological parameters and prognosis of breast cancer patients were analyzed.The expression of MAGE-C2 was also detected by RT-PCR in breast cancer cell MCF-7 and MDA-MB-231 treated with DNA methylase inhibitor 5-aza-2′-deoxycytidine(5-aza-CdR)and histone deacetylase inhibitor trichostatin A(TSA).Results The positive expression rates of MAGE-C2 mRNA and protein were 61.7%(37/60)and 58.3%(35/60)in breast cancer specimens,respectively,while negative expressed in breast and begin disease specimens.MAGE-C2 protein expression was associated with tumor grade,histological type and blood vessel invasion of breast cancer patients(P<0.05).The incidence of recurrence-free survival of patients with positive MAGE-C2 expression were lower than that of patients with negative MAGE-C2 expression(P<0.05).Multivariate Cox regression analysis showed that the clinical stage(P<0.01),lymph node metastasis(P<0.05)and MAGE-C2 expression(P<0.05)were the independent prognostic factors of breast cancer patients.The MAGE-C2 mRNA was not observed in the control and TSA treated breast cancer cells while upregulated in the 5-aza-CdR treated cells.Besides,5-aza-CdR combined with TSA further enhanced MAGE-C2 mRNA level in breast cancer cells(P<0.05).Conclusions MAGE-C2 is one of the tumor-specific antigen and its expression is related with the poor prognosis of breast cancer patients.DNA methylation and histone acetylation may be an important regulation mechanism of MAGE-C2 gene expression.