Ponatinib (AP24534) is a novel potent inhibitor of oncogenic RET mutants associated with thyroid cancer.

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De Falco V, Buonocore P, Muthu M, Torregrossa L, Basolo F, Billaud M, Gozgit JM, Carlomagno F, Santoro M

Ponatinib (AP24534) is a novel potent inhibitor of oncogenic RET mutants associated with thyroid cancer.

J Clin Endocrinol Metab. 2013 May;98(5):E811-9. doi: 10.1210/jc.2012-2672. Epub 2013 Mar 22.

PubMed ID

23526464 [ View in PubMed

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Abstract

CONTEXT: The RET tyrosine kinase encoding gene acts as a dominantly transforming oncogene in thyroid carcinoma and other malignancies. Ponatinib (AP24534) is an oral ATP-competitive tyrosine kinase inhibitor that is in advanced clinical experimentation in leukemia. OBJECTIVE: We tested whether ponatinib inhibited RET kinase and oncogenic activity. METHODS: Ponatinib activity was studied by an in vitro RET immunocomplex kinase assay and immunoblotting. The effects of ponatinib on proliferation of human TT, MZ-CRC-1, and TPC-1 thyroid carcinoma cells, which harbor endogenous oncogenic RET alleles, and of NIH3T3 fibroblasts transfected with oncogenic RET mutants were determined. Ponatinib activity on TT cell xenografted tumors in athymic mice was measured. RESULTS: Ponatinib inhibited immunopurified RET kinase at the IC(5)(0) of 25.8 nM (95% confidence interval [CI] = 23.15-28.77 nM). It also inhibited (IC(5)(0) = 33.9 nM; 95% CI = 26.41-43.58 nM) kinase activity of RET/V804M, a RET mutant displaying resistance to other tyrosine kinase inhibitor. Ponatinib blunted phosphorylation of point-mutant and rearranged RET-derived oncoproteins and inhibited proliferation of RET-transformed fibroblasts and RET mutant thyroid carcinoma cells. Finally, after 3 weeks of treatment with ponatinib (30 mg/kg/d), the volume of TT cell (medullary thyroid carcinoma) xenografts was reduced from 133 mm(3) to an unmeasurable size (difference = 133 mm(3), 95% CI = -83 to 349 mm(3)) (P < .001). Ponatinib-treated TT cell tumors displayed a reduction in the mitotic index, RET phosphorylation, and signaling. CONCLUSIONS: Ponatinib is a potent inhibitor of RET kinase and has promising preclinical activity in models of RET-driven medullary thyroid carcinoma.

DrugBank Data that Cites this Article

Drug Targets

Drug	Target	Kind	Organism	Pharmacological Action	Actions
Ponatinib	Proto-oncogene tyrosine-protein kinase receptor Ret	Protein	Humans	Unknown	Inhibitor	Details