【作者】 李厚勇；

【导师】 周梁；

【作者基本信息】 复旦大学 ， 耳鼻咽喉科学， 2009， 博士

【摘要】 背景研究表明在皮肤恶性黑色素瘤中癌基因NRAS的突变率为9-15%,BRAF的突变率为60-66%,而在视网膜恶性黑色素瘤中却没有发现NRAS和BRAF基因的突变。在鼻腔恶性黑色素瘤中NRAS和BRAF基因的突变率未见报道。本部分实验旨在研究鼻腔恶性黑色素瘤标本中NRAS和BRAF的突变。方法：提取12例鼻腔恶性黑色素瘤新鲜组织中的DNA,经PCR扩增后,进行基因序列分析并与正常NRAS和BRAF基因序列比较。结果：12例标本中,未发现NRAS基因突变,8例标本中发现1例BRAF基因突变。结论：鼻腔恶性黑色素瘤的NRAS和BRAF突变率远低于皮肤恶性黑色素瘤。背景研究表明Ras-Raf-MAPKK-ERK信号通路的持续活化在皮肤恶性黑色素瘤的发生、发展中起着重要作用,而这一信号通路的持续活化与NRAS和BRAF基因的高突变率有关。在前面的研究中,我们在鼻腔恶性黑色素瘤中未发现NRAS基因突变,BRAF基因的突变率也很低,那么在鼻腔恶性黑色素瘤中是否存在ERK的持续活化呢?本部分实验旨在研究鼻腔恶性黑色素瘤中持续活化的ERK。方法：用Western蛋白印迹法检测12例鼻腔恶性黑色素瘤标本中活化的ERK。结果：12例鼻腔恶性黑色素瘤标本中,有8例表达活化的ERK,占66%。结论：：ERK的持续活化是鼻腔恶性黑色素瘤的发病机制之背景：研究表明ERK的持续活化在恶性黑色素瘤的发生、发展中起着重要作用,ERK的激活对于Ras诱导的许多细胞反应、许多转录因子(Elk1、cEts1、c-Ets2)的激活以及许多激酶(如p90rsk1、MNK1、MNK2)的激活是至关重要的。在恶性黑色素瘤中激活的ERK究竟参与了哪些细胞反应还有待进一步研究。本部分实验旨在研究ERK对细胞周期的影响及其机制。方法：选用持续活化的ERK细胞株A-375,用MEK抑制剂PD98059阻断ERK信号通路,观察细胞生长曲线并用MTT法观察细胞增殖,用流式细胞仪检测细胞周期,用Western蛋白印迹法检测活化的ERK和细胞周期蛋白Cycline D1的表达。结果：ERK信号通路阻断后,G0-1期细胞所占比例明显增加(p<0.01),S期细胞所占比例明显降低(p<0.01),同时细胞周期蛋白Cyclin Dl无表达。结论：ERK信号通路阻断后,细胞阻滞于G0-1期。其机制与细胞周期蛋白Cyclin D1的合成抑制有关。背景：研究表明ERK的持续活化在恶性黑色素瘤的发生、发展中起着重要作用,同时有研究表明ERK信号转导通路在急性髓细胞白血病(acute myeloid leukemia AML)中起着一定的抗凋亡作用。而ERK信号通路是否在恶性黑色素瘤细胞中也有抗凋亡作用尚无报道。本部分实验旨在探索活化的ERK信号通路在恶性黑色素瘤细胞中的抗凋亡作用。方法：用恶性黑色素瘤细胞A-375分别在含血清、含血清加PD98059、无血清、无血清加PD98059培液中培养,用流式细胞仪检测各组细胞凋亡率,并用荧光显微镜和激光共聚焦显微镜观察凋亡细胞,比较各组细胞间凋亡差异。结果：ERK通路激活时,无血清组与含血清组细胞凋亡无显著性差异,ERK通路阻断后,含血清组与无血清组细胞凋亡有显著性差异。结论：ERK信号转导通路在恶性黑色素瘤细胞中有一定的抗凋亡作用。更多还原

【Abstract】 Background In previous studies, the mutations of NRAS have been identified in 9-15% of cutaneous melanomas and the mutations of BRAF have been identified in 60-66% of cutaneous melanomas. And no NRAS and BRAF mutation was detected in uveal melanomas. But we don’t know the mutations of NRAS and BRAF in nasal melanomas. So we study the mutations of NRAS and BRAF in nasal melanomas.Method:Extract the DNA from 12 fresh nasal melanomas and amplification by PCR,and then analysis the DNA sequence.Result:Mutations in NRAS were not detected in 12 cases,Mutations were detected in 1 of 8 cases. Conclution:The mutations rate of NRAS and BRAF in nasal melanomas is lower than that of cutaneous melanomas. Background The Ras-Raf-MAPKK-ERKpathway plays a central role in regulating the growth and survival of cells from the cutaneous melanomas,The high constitutive ERK activity in melanoma is most likely a consequence of mutations in NRAS and BRAF.In our previous studies, The mutations rate of NRAS and BRAF in nasal melanomas is lower than that of cutaneous melanomas. How about the activated ERK in nasal melanomas, we study the phosphorylated ERK protein in nasal melanomas.Method:We examined ERK activation in a total of 12 nasal melanoma samples by Western blot.Result:Western blot analyses revealed phosphorylated ERK protein in 8 of 12 (66%) of the nasal melanomas.Conclution:The constitutive ERK activity is one of the pathogenesis in nasal melanomas. Background:The constitutive activated ERK plays a central role in regulating the growth and survival of cells from the melanomas. The activated ERK plays a central role in many cellular responses mediated by Ras,and it plays a central role in many kinases activation (such as p90rsk1,MNK1,MNK2) and many transcription factors activation(such as Elk1、cEts1、c-Ets2). However,the activated ERK associated with melanoma proliferation is not well understood. We want to investigate the mechanism and effects of inactivated ERK on cell cycle.Method:We inhibit the downstream of MEK/ERK pathway by PD98059.The effect of inactivated ERK on cell cycle of melanoma cell line was evaluated by cell growth curve and MTT assay. Flow cytometric analysis was performed for cell cycle progression. Western blot was used to detect the expression of cyclin D1 and activated ERK. Result:A significant increase in G0-1 phases and a significant decrease in S phases was observed after the inhibition of MEK/ERK downstream. The cyclin D1 were not detected by western blot after the inhibition of MEK/ERK downstream.Conclution:The cell cycle was arrested in G0-1 by the inactivated ERK. The mechanism is the inhibition of cyclin D1 synthesis. Background:The constitutive activated ERK plays a central role in regulating the growth and survival of cells from the melanomas.The activated ERK plays a role in antiapoptosis in acute myeloid leukemia (AML).There is no report about the antiapoptosis effects of the ERK in melanoma. We want to investigate the antiapoptosis effects of ERK in melanomaMethods:The melanoma cell line A-375 were cultured in the 10%FBS or 1%FBS with PD98059 or serum-free or serum-free with PD98059 conditions. We check the melanoma cells apoptosis in four groups by flow cytometric analysis, and we compare the apoptosis rate in four groups.Result:There is no definite deference between 10%FBS without PD98059 and serum-free without PD98059 group in the cells apoptosis, But there is definite deference between 10%FBS with PD98059 and serum-free with PD98059 group in the cells apoptosis. Conclusion There is a antiapoptosis effects of the ERK in melanoma.更多还原