摘要目的：研究野生型BRAF及突变型BRAFV600E背景下Mps1激酶对BRAFWT／MEK／ERK通路的影响。方法（1）在BRAF野生型背景的黑色素瘤细胞中单独或联合转染pBabe－puro－GST－BRAF－WT／pBabe－puro－GST－BRAFV600E、pBabe－puro－GFP－Mps1－WT 及空载体，应用 Western blot方法来检测 Mps1及 p－ERK 表达水平。（2）用 pSUPER－Mps1反转录病毒感染 BRAF 野生型及BRAFV600E突变型背景黑色素瘤细胞，敲低内源性Mps1，Western blot法检测Mps1及p－ERK表达水平。（3）在BRAFV600E突变型背景的黑色素瘤细胞中转染pBabe－puro－GFP－Mps1，Western blot法检测Mps1及p－ERK表达水平。结果（1）在BRAF野生型背景的黑色素瘤细胞中转染pBabe－puro－GST－BRAF－WT及pBabe－puro－GFP－Mps1－WT，与未处理组及转染空载体组相比，p－ERK水平显著降低（ P＜0．01）；在BRAF野生型背景的黑色素瘤细胞中转染pBabe－puro－GST－BRAFV600E及pBabe－puro－GFP－Mps1－WT，与未处理组及转染空载体组相比，p－ERK表达水平未发生明显变化。（2）在BRAF野生型背景的黑色素瘤细胞中敲低内源性Mps1后，与对照组相比p－ERK含量增多；而在BRAFV600E突变型黑色素瘤细胞中敲低内源性Mps1后，与对照组相比p－ERK含量未发生明显变化。（3）转染Mps1的BRAFV600E突变型细胞中 p－ERK 水平较对照组及空载体组没有发生显著变化。结论Mps1激酶和BRAFWT／MEK／ERK通路之间存在一条自动调节的负反馈回路，而癌基因BRAFV600E表现出对该负反馈回路的抵抗作用。

abstractsObjective To study the effect of Mps1 on BRAFWT/MEK/ERK pathway in the presence of wild type BRAF or BRAFV600E in melanoma.Methods Melanoma cells harboring BRAFWT genotype were transfected either with pBabe-puro-GST-BRAF-WT and/or pBabe-puro-GFP-Mps1-WT or pBabe-puro-GST-BRAFV600E and/or pBabe-puro-GFP-Mps1-WT, followed by Western blot to detect Mps1 and p-ERK expression.The melanoma cells harboring BRAFWT and BRAFV600E genotype were infected with pSUPER-Mps1 retrovirus to knockdown the endogenous Mps1 protein, followed by Western blot to detect Mps1 and p-ERK expression.Meanwhile, melanoma cells harboring BRAFV600E genotype were infected with pBabe-puro-GFP-Mps1 and Western blot was performed to detect Mps1 and p-ERK expression. Results In melanoma cells harboring BRAFWT genotype and transfected with pBabe-puro-GST-BRAF-WT and pBabe-puro-GFP-Mps1-WT, phospho-ERK levels were notably reduced as compared to either negative control or empty vector.However, cells transfected with pBabe-puro-GST-BRAFV600E and pBabe-puro-GFP-Mps1-WT, phospho-ERK levels did not change significantly compared with either negative control or empty vector.Knockout of Mps1 in BRAF wild-type cell lines led to an increased ERK activity.However, there was no significant change of ERK activity in BRAFV600E cell lines in the absence of Mps1.The expression of p-ERK in BRAFV600E mutant cell lines infected with pBabe-puro-GFP-Mps1-WT did not show any significant difference from either negative control or empty vector. Conclusions Based on these findings, it suggests that there exists an auto-regulatory negative feedback loop between the Mps1 kinase and BRAFWT/ERK signaling.Oncogenic BRAFV600E abrogates the regulatory negative feedback loop of Mps1 on the MAPK pathway.