semaxinib and Carcinoma--Papillary

Thyroid neoplasia is frequently associated with rearranged during transfection (RET) proto-oncogene mutations that cause hyperactivation of RET kinase activity. Selective inhibition of RET-mediated signaling should lead to an efficacious therapy. SU5416 is a potent inhibitor of vascular endothelial cell growth factor receptor, c-Kit, and FLT-3 receptor tyrosine kinases presently used in clinical trials. We found that SU5416 inhibits RET with similar potency, both in cell-free assays and in cells, thus causing proliferation arrest in oncogenic RET-transfected cells and in papillary thyroid carcinoma (PTC) cells expressing the RET/PTC1 oncogene, but not in RET-negative control cells. SU5416 inhibited RET-mediated signaling through the extracellular signal regulated kinase (ERK) and JNK pathways. In addition, we show that a naturally occurring MEN2 mutation at codon 804 confers resistance to SU5416, but not to the related compound SU4984. We provide a possible explanation to these results by using molecular docking. Finally, SU5416 was also assessed against an array of 52 tyrosine and serine/threonine kinases.

Topics: Animals; Carcinoma, Papillary; Female; Humans; Indoles; Insecta; Mice; Mice, Nude; Models, Biological; Models, Molecular; Mutant Proteins; NIH 3T3 Cells; Phosphorylation; Protein Kinase Inhibitors; Protein Kinases; Proto-Oncogene Mas; Proto-Oncogene Proteins c-ret; Pyrroles; Sensitivity and Specificity; Thyroid Neoplasms; Tumor Cells, Cultured; Xenograft Model Antitumor Assays