1.Study of negative feedback between wild-type BRAF or RAFV600E and Mps1 in melanoma.
Ling ZHANG ; Chanting HE ; Yanghui BI ; Feng LIU ; Heyang CUI ; Juan WANG ; Bin SONG ; Ruyi SHI ; Bin YANG ; Fang WANG ; Zhiwu JIA ; Zhenxiang ZHAO ; Jing LIU ; E-mail:liujing5585@163.com.
Chinese Journal of Pathology 2015;44(4):274-277
OBJECTIVETo study the effect of Mps1 on BRAFWT/MEK/ERK pathway in the presence of wild type BRAF or BRAFV600E in melanoma.
METHODSMelanoma 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.
RESULTSIn 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.
CONCLUSIONSBased 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.
Cell Cycle Proteins ; metabolism ; Cell Line, Tumor ; Humans ; MAP Kinase Signaling System ; Melanoma ; genetics ; metabolism ; Mutation ; Phenotype ; Protein-Serine-Threonine Kinases ; metabolism ; Protein-Tyrosine Kinases ; metabolism ; Proto-Oncogene Proteins B-raf ; metabolism ; Signal Transduction ; Transfection
Result Analysis
Print
Save
E-mail