线粒体融合蛋白?2在黑色素瘤组织表达及对肿瘤细胞生物活性的影响

Expression of mitochondrial fusion protein-2 in melanoma tissues and its effect on the biological activity of tumor cells

目的积极探索黑色素瘤高转移性的分子机制,寻找新的肿瘤标志物及治疗靶点具有重要的临床意义。文中研究线粒体融合蛋白-2(MFN2)在皮肤黑色素瘤组织、黑色素瘤周围组织中的表达,并分析其与患者临床参数的相关性;同时探讨MFN2与黑色素瘤的生物学行为的相关性。方法应用免疫组织化学方法检测Med19蛋白在皮肤黑色素瘤组织、黑色素瘤周围组织中的表达,并分析MFN2的表达量与患者临床因素的相关性。将含有MFN2编码序列的慢病毒载体(Lenti-MFN2)感染黑色素瘤细胞B16设为实验组;绿色荧光蛋白基因的慢病毒(Lenti-GFP)设为对照组。采用实时荧光定量PCR(qRT-PCR)和Western blot检测转染后细胞中MFN2及Ras-Raf1-ERK1/2信号通路相关mRNA及蛋白的表达;流式细胞仪检测转染细胞周期和凋亡变化;MTT法和集落形成实验检测细胞活力和增殖能力的变化。结果MFN2在黑色素瘤周围组织的阳性表达率显著高于皮肤黑色素瘤组织(83.9%vs 30.6%,P<0.05);MFN2的表达与淋巴结转移及TNM分期均有关(P<0.05)。与对照组相比,实验组B16细胞的增殖活性和集落形成能力均被显著抑制(P<0.05);与对照组相比,实验组中B16细胞的G0/G 1期细胞比例显著增加[(46.3±10.3)%vs(67.9±12.6)%],凋亡率显著增高[(12.5±1.6)%vs(57.4±12.6)%],差异均有统计学意义(P<0.05)。与对照组相比,实验组中Ras、Raf、ERK1/2 mRNA和蛋白的表达均显著降低(P<0.05)。结论MFN2在黑色素瘤组织中呈低表达。通过上调MFN2的表达可抑制黑色素瘤增殖,促进细胞的凋亡,这可能与其抑制Ras-MAPK信号通路的活性有关。

Objective Melanoma is a malignant tumor with high clinical malignancy,rapid progression,poor prognosis and high mortality.It is of great clinical significance to explore the molecular mechanism of high metastasis of melanoma and find new tumor markers and therapeutic targets.The expression of mitochondrial fusion protein-2(MFN2)in cutaneous melanoma tissues and peritumoral tissues was studied,and its correlation with clinical parameters was analyzed.The correlation between MFN2 and the biological behavior of melanoma was also discussed.Methods Immunohistochemistry was used to detect the expression of Med19 protein in cutaneous melanoma tissues and peritumoral tissues,and to analyze the correlation between MFN2 expression and clinical factors in patients.The lentiviral vector containing MFN2 coding sequence(Lenti-MFN2)infected with melanoma cell B16 was set up as the study group,and the lentivirus with green fluorescent protein gene(Lenti-GFP)as the control group.The mRNA and protein expressions of MFN2 and Ras-Raf1-ERK1/2 signaling pathways in transfected cells were detected by real-time quantitative PCR(qRT-PCR)and Western blot.Flow cytometry was used to detect changes in cell cycle and apoptosis.MTT assay and colony formation assay were used to detect changes in cell viability and proliferation capacity.Results The positive expression rate of MFN2 in peritumoral tissues was significantly higher than that in the skin melanoma tissues(83.9%vs 30.6%,P<0.05).MFN2 expression was associated with both lymph node metastasis and TNM staging(P<0.05).Compared with the control group,the proliferation activity and colony forming ability of B16 cells in the study group were significantly inhibited(P<0.05);the proportion of G0/G1 phase cells in B16 cells in the study group significantly increased[(46.3±10.3)%vs(67.9±12.6)%],and the apoptosis rate significantly increased[(12.5±1.6)%vs(57.4±12.6)%],with statistically significant differences(P<0.05).In comparison with the control group,the expression of Ras,Raf,ERK1/2 mRNA and protein in the study group significantly decreased(P<0.05).Conclusion MFN2 is down-regulated in melanoma tissues.Up-regulation of MFN2 expression can inhibit melanoma proliferation and promote cell apoptosis,which may be related to the inhibition of Ras-MAPK signaling pathway activity.