imetelstat and Carcinoma--Neuroendocrine

Advanced thyroid cancer is not amenable to therapy with conventional cytotoxic chemotherapy. However, newer advances in the understanding of the molecular pathogenesis of different subtypes of thyroid cancer have provided new opportunities for the evaluation of molecularly targeted therapies. This has led to multiple clinical trials using various multi-kinase inhibitors and the subsequent US FDA approval of sorafenib for differentiated thyroid cancer and vandetanib and cabozantinib for medullary thyroid carcinoma. This review provides a summary of the current literature for the treatment of advanced thyroid carcinoma and future directions in this disease.

Topics: Anilides; Antineoplastic Agents; Axitinib; Carcinoma, Neuroendocrine; DNA Mutational Analysis; Drug Approval; Humans; Imidazoles; Indazoles; Indoles; MAP Kinase Signaling System; Molecular Targeted Therapy; Niacinamide; Oligonucleotides; Phenylurea Compounds; Phosphatidylinositol 3-Kinases; Piperidines; Proto-Oncogene Proteins c-ret; Pyridines; Pyrimidines; Pyrroles; Quinazolines; Quinolines; Sorafenib; Sulfonamides; Sunitinib; Thyroid Neoplasms; United States; United States Food and Drug Administration; Vascular Endothelial Growth Factor A

Clinical evidence shows that dual inhibition of kinases as well angiogenesis provides ideal therapeutic option in the treatment of medullary thyroid carcinoma (MTC) than inhibiting either of these with the events separately. Although treatment with dual inhibitors has shown good clinical responses in patients with MTC, it has been associated with serious side effects. Some inhibitors are active agents for both angiogenesis or kinase activity. Owing to narrow therapeutic window of established inhibitors, the present study aims to identify high affinity dual inhibitors targeting RET and VEGFR2 respectively for kinase and angiogenesis activity. Established inhibitors like Vandetanib, Cabozantinib, Motesanib, PP121, RAF265 and Sunitinib served as query parent compounds for identification of structurally similar compounds by Tanimoto-based similarity searching with a threshold of 95% against the PubChem database. All the parent inhibitors and respective similar compounds were docked against RET and VEGFR2 in order to retrieve high affinity compounds with these two proteins. AGN-PC-0CUK9P PubCID: 59320403 a compound related to PPI21 showed almost equal affinity for RET and VEGFR2 and unlike other screened compounds with no apparent bias for either of the receptors. Further, AGN- PC-0CUK9P demonstrated appreciable interaction with both RET and VEGFR2 and superior kinase activity in addition to showed optimal ADMET properties and pharmacophore features. From our in silico investigation we suggest AGN-PC-0CUK9P as a superior dual inhibitor targeting RET and VEGFR2 with high efficacy which should be proposed for pharmacodynamic and pharmacokinetic studies for improved treatment of MTC.

Topics: Angiogenesis Inhibitors; Anilides; Carcinoma, Neuroendocrine; Databases, Chemical; Drug Discovery; Humans; Imidazoles; Indoles; Molecular Docking Simulation; Molecular Structure; Niacinamide; Oligonucleotides; Piperidines; Protein Binding; Protein Kinase Inhibitors; Proto-Oncogene Proteins c-ret; Pyrazoles; Pyridines; Pyrimidines; Pyrroles; Quinazolines; Sunitinib; Thyroid Neoplasms; Vascular Endothelial Growth Factor Receptor-2

Medullary thyroid cancer (MTC) is frequently associated with mutations in the tyrosine kinase Ret and with increased expression of vascular endothelial growth factor (VEGF) and VEGF receptor 2 (VEGFR2). Motesanib is an investigational, orally administered small molecule antagonist of VEGFR1, 2, and 3; platelet-derived growth factor receptor (PDGFR); Kit; and possibly Ret.. The aim of this study was to investigate the effects of motesanib on wildtype and mutant Ret activity in vitro and on tumor xenograft growth in a mouse model of MTC.. In cellular phosphorylation assays, motesanib inhibited the activity of wild-type Ret (IC(50)=66 nM), while it had limited activity against mutant Ret C634W (IC(50)=1100 nM) or Ret M918T (IC(50)>2500 nM). In vivo, motesanib significantly inhibited the growth of TT tumor cell xenografts (expressing Ret C634W) and significantly reduced tumor blood vessel area and tumor cell proliferation, compared with control. Treatment with motesanib resulted in substantial inhibition of Ret tyrosine phosphorylation in TT xenografts and, at comparable doses, in equivalent inhibition of VEGFR2 phosphorylation in both TT xenografts and in mouse lung tissue.. The results of this study demonstrate that motesanib inhibited thyroid tumor xenograft growth predominantly through inhibition of angiogenesis and possibly via a direct inhibition of VEGFR2 and Ret expressed on tumor cells. These data suggest that targeting angiogenesis pathways and specifically the VEGF pathway may represent a novel therapeutic approach in the treatment of MTC.

Topics: Animals; Antineoplastic Agents; Carcinoma, Neuroendocrine; Cell Line, Tumor; Cells, Cultured; Female; Human Umbilical Vein Endothelial Cells; Humans; Indoles; Mice; Mice, Nude; Niacinamide; Oligonucleotides; Polymorphism, Single Nucleotide; Proto-Oncogene Proteins c-ret; Thyroid Neoplasms; Transfection; Xenograft Model Antitumor Assays