The important roles of RET, VEGFR2 and the RAF/MEK/ERK pathway in cancer treatment with sorafenib

• Published in: Acta pharmacologica Sinica Vol. 33; no. 10; pp. 1311 - 1318
• Main Authors: Mao, Wei-feng, Shao, Min-hua, Gao, Pin-ting, Ma, Ji, Li, Hui-juan, Li, Gai-ling, Han, Bao-hui, Yuan, Chong-gang
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 01.10.2012; Nature Publishing Group
• Subjects: Antineoplastic Agents - pharmacology; Antineoplastic Agents - therapeutic use; Biomedical and Life Sciences; Biomedicine; Blotting, Western; Cell Culture Techniques; Cell Line, Tumor; Cell Proliferation - drug effects; ERK; Gene Expression Regulation, Neoplastic - drug effects; HepG2细胞; Humans; Immunology; Internal Medicine; MAP Kinase Signaling System - drug effects; MAP Kinase Signaling System - genetics; Medical Microbiology; MEK; Neoplasms - drug therapy; Neoplasms - enzymology; Neoplasms - pathology; Niacinamide - analogs & derivatives; Niacinamide - pharmacology; Niacinamide - therapeutic use; Original; original-article; Pharmacology/Toxicology; Phenylurea Compounds - pharmacology; Phenylurea Compounds - therapeutic use; Proto-Oncogene Proteins c-ret - antagonists & inhibitors; Proto-Oncogene Proteins c-ret - genetics; Real-Time Polymerase Chain Reaction; RET; RNA Interference - drug effects; Vaccine; Vascular Endothelial Growth Factor Receptor-2 - antagonists & inhibitors; Vascular Endothelial Growth Factor Receptor-2 - genetics; Western印迹; 信号通路; 受体酪氨酸激酶; 癌症治疗; sorafenib (BAY 43-9006); VEGFR2; RET; cancer; RAF/MEK/ERK pathway; protein kinase
• ISSN: 1671-4083; 1745-7254; 1745-7254
• DOI: 10.1038/aps.2012.76

Aim： To elucidate the roles of receptor tyrosine kinases RET and VEGFR2 and the RAF/MEK/ERK signaling cascade in cancer treatment with sorafenib. Methods： The cell lines A549, HeLa, and HepG2 were tested. The enzyme activity was examined under cell-free conditions using 384-well microplate assays. Cell proliferation was evaluated using the Invitrogen Alarmar Blue assay. Gene expression was analyzed using the Invitrogen SYBR Green expression assays with a sequence detection system. Protein expression analysis was performed using Western blotting.Results： Sorafenib potently suppressed the activities of cRAF, VEGFR2, and RET with IC50 values of 20.9, 4, and 0.4 nmol/L, respectively. Sorafenib inhibited cRAF, VEGFR2, and RET via non-ATP-competitive, ATP-competitive and mixed-type modes, respectively. In contrast, sorafenib exerted only moderate cytotoxic effects on the proliferation of the 3 cell lines. The IC50 values for inhibition of A549, HeLa, and HepG2 cells were 8572, 4163, and 8338 nmol/L, respectively. In the 3 cell lines, sorafenib suppressed the cell proliferation mainly by blocking the MEK/ERK downstream pathway at the posttranscriptional level, which in turn regulated related gene expression via a feed-back mechanism.Conclusion： This study provides novel evidence that protein kinases RET and VEGFR2 play crucial roles in cancer treatment with sorafenib.