title: Functional characterization of the novel BRAF complex mutation, BRAF(V600delinsYM) , identified in papillary thyroid carcinoma.
abstract: An activating mutation in the BRAF gene is the most common genetic alteration in papillary thyroid carcinomas (PTCs). The mutation in PTCs is almost a c.1799T>A transversion, resulting in a p.V600E amino acid substitution (BRAF(V600E) ). Here, we report a novel complex BRAF mutation identified in 4/492 Japanese PTC cases (0.81%). The mutation was comprised of one nucleotide substitution at position 1798, followed by an in-frame insertion of three nucleotides, c.1798delinsTACA in Exon 15, resulting in p.V600delinsYM. In silico three-dimensional protein structure prediction implied altered kinase activity of this mutant. In vitro kinase assay and western blotting revealed that this mutation conferred high kinase activity on the BRAF protein, leading to constitutive activation of the MAPK signaling pathway. The mutation also showed high transforming ability in focus formation assay using NIH3T3 cells. The degree of all the functional characteristics was comparable to that of BRAF(V600E) , and treatment with a BRAF inhibitor Sorafenib was also equally effective in this mutant. These findings suggest that the novel BRAF mutation, BRAF(V600delinsYM) , is a gain-of-function mutation and plays an important role in PTC development.
authors: Department of Radiation Medical Sciences, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki, Japan.
authors: Michiko
authors: M
authors: Matsuse
authors: Norisato
authors: N
authors: Mitsutake
authors: Susumu
authors: S
authors: Tanimura
authors: Tomoo
authors: T
authors: Ogi
authors: Eijun
authors: E
authors: Nishihara
authors: Mitsuyoshi
authors: M
authors: Hirokawa
authors: Cesar S
authors: CS
authors: Fuziwara
authors: Vladimir A
authors: VA
authors: Saenko
authors: Keiji
authors: K
authors: Suzuki
authors: Akira
authors: A
authors: Miyauchi
authors: Shunichi
authors: S
authors: Yamashita
mesh_terms: D016475:3T3 Cells; D019943:Amino Acid Substitution; D000818:Animals; D001557:Benzenesulfonates / Q000494:pharmacology; D019556:COS Cells; D002277:Carcinoma / Q000188:drug therapy / Q000235:genetics*; D002291:Carcinoma, Papillary; D002460:Cell Line; D002471:Cell Transformation, Neoplastic / Q000235:genetics*; D002522:Chlorocebus aethiops; D004273:DNA, Neoplasm / Q000235:genetics*; D006801:Humans; D051379:Mice; D009154:Mutation; D009536:Niacinamide / Q000031:analogs & derivatives; D010671:Phenylurea Compounds; D048493:Proto-Oncogene Proteins B-raf / Q000235:genetics*; D011725:Pyridines / Q000494:pharmacology; D000077157:Sorafenib; D000077273:Thyroid Cancer, Papillary; D013964:Thyroid Neoplasms / Q000188:drug therapy / Q000235:genetics*
chemical_list: D001557:Benzenesulfonates; D004273:DNA, Neoplasm; D010671:Phenylurea Compounds; D011725:Pyridines; D009536:Niacinamide; D000077157:Sorafenib; C482119:BRAF protein, human; D048493:Proto-Oncogene Proteins B-raf