aee-788 and Thyroid-Neoplasms

This study evaluated the role of EGF and the effects of EGF-targeting drugs (Cetuximab, AEE 788) on growth, apoptosis, and autocrine VEGF-secretion of thyroid cancer (TC) cells. Autocrine activation of the epidermal growth factor receptor (EGF-R) is commonly regarded to contribute to the malignant phenotype of TC cells and may therefore represent a rational therapeutic target. Out of a number of TC cell lines two anaplastic (Hth74, C643), one follicular (FTC133), and one papillary thyroid cancer cell line (TPC1) were analyzed in depth for VEGF-R-and EGF-R-expression, basal and EGF-stimulated (1-100 ng/ml) VEGF protein secretion and proliferation. Subsequently the antiprolifereative and antiangiogenic effect of cetuximab (Erbitux), a monoclonal antibody that blocks the EGF-R and AEE 788, a novel dual-kinase inhibitor of EGF-R and VEGF-R were assessed, and the downstream EGF-R signal transduction was analyzed by means of detecting phosphorylated pEGF-R, pVEGF-R, pAkt, and p-MAPK. EGF stimulated VEGF-mRNA expression and protein secretion in all TC cell lines. The EGF-R antagonist Cetuximab consistently decreased VEGF secretion in all TC cell lines (min. 15%, n.s. in C643 cells and max. 90% in Hth74 cells, P < 0.05), but did not affect tumor cell proliferation in vitro. In contrast, the EGF-R- and VEGF-R-kinase inhibitor AEE 788 not only reduced VEGF secretion (min. 55%, P < 0.05 in C643 and max. 75%, P < 0.05, in FTC133), but also exhibited a dose-dependent inhibition of tumor cell proliferation (min. 75%, P < 0.05 in C643 and max. 95%, P < 0.05 in Hth74) and was a potent inductor of apoptosis in two of four TC cell lines. These effects were always accompanied by reduced levels of pEGF-R, pVEGF-R, pAkt, and pMAPK. Although inhibition of the EGF-receptor by Cetuximab potently disrupts autocrine secretion of VEGF, only the concurrent inhibition of the VEGF- and EGF receptor, e.g., by AEE 788 induces reduced proliferation and apoptosis in vitro. This suggests a particular rationale for the use of tyrosine kinase inhibitors with dual modes of action such as AEE 788 in thyroid cancer.

Topics: Antibodies, Monoclonal; Antibodies, Monoclonal, Humanized; Antineoplastic Agents; Apoptosis; Cell Line, Tumor; Cell Proliferation; Cetuximab; Drug Evaluation, Preclinical; Epidermal Growth Factor; ErbB Receptors; Humans; Purines; Receptors, Vascular Endothelial Growth Factor; Signal Transduction; Thyroid Neoplasms; Vascular Endothelial Growth Factor A

Patients with radioiodine-resistant follicular thyroid cancer (FTC) have a poor prognosis, if metastasized, with currently available treatment modalities. Epidermal growth factor (EGF) and vascular endothelial growth factor (VEGF) and their receptors (EGFR and VEGFR) have been reported to be overexpressed in FTC and have been implicated in FTC development. We hypothesized that inhibiting the phosphorylation of EGFR and VEGFR by treatment with NVP-AEE788 (AEE788), a novel dual specific EGFR and VEGFR inhibitor, either alone or in combination with paclitaxel, would inhibit the growth of FTC xenografts in an orthotopic nude mouse model.. To confirm previous reports, EGF and EGFR expression and vascularity were analyzed in human samples of FTC, Hürthle cell carcinoma, and normal thyroid tissues. EGFR expression in four FTC cell lines was measured using Western blotting. The antitumor effect of AEE788 on FTC cells in vitro was evaluated using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assays and Western blotting. The effect of AEE788, alone and in combination with paclitaxel, on FTC tumor growth in an orthotopic nude mouse model was also investigated. Immunohistochemical analysis of EGFR and VEGFR signaling status, cell proliferation, apoptosis, and microvessel density was done.. EGF, EGFR, and vascularity were increased in human thyroid tumor samples and EGFR was increased in FTC cells. AEE788 inhibited FTC cell growth in vitro and reduced the phosphorylation status of EGFR, VEGFR, and two downstream targets, AKT and mitogen-activated protein kinase, in FTC cells. AEE788 alone and, to a greater extent, AEE788 plus paclitaxel suppressed FTC tumor growth in the thyroids of nude mice.. Dual inhibition of EGFR and VEGFR by AEE788 could represent a novel approach to the treatment of radioiodine-resistant FTC.

Topics: Adenocarcinoma, Follicular; Animals; Antineoplastic Combined Chemotherapy Protocols; Blotting, Western; Cell Line, Tumor; Cell Proliferation; Disease Models, Animal; Disease Progression; ErbB Receptors; Humans; Male; Mice; Mice, Nude; Paclitaxel; Phosphorylation; Predictive Value of Tests; Prognosis; Purines; Receptors, Vascular Endothelial Growth Factor; Structure-Activity Relationship; Thyroid Neoplasms; Xenograft Model Antitumor Assays

The epidermal growth factor receptor (EGFR), a transmembrane tyrosine kinase (TK) receptor that mediates proliferation and survival signaling, is expressed in a wide variety of normal and neoplastic tissues. EGFR inhibitors have produced objective responses in patients with non-small-cell lung carcinomas harboring activating EGFR TK domain somatic mutations.. Because the EGFR pathway has been reported to be important for the pathophysiology of thyroid carcinoma, we investigated the expression and mutational status of EGFR in 14 thyroid carcinoma cell lines as well as its functional role by evaluating their in vitro sensitivity to AEE788, a new dual-family EGFR/ErbB2 and vascular endothelial growth factor receptor TK inhibitor. We also evaluated the mutational status, mRNA and protein expression, as well as phosphorylation status of EGFR in a panel of thyroid carcinoma specimens.. EGFR expression and phosphorylation in the thyroid carcinoma cell lines and tissue specimens were present but not stronger than in noncancerous thyroid tissue. EGFR TK domain mutations were detected in two of 62 histological specimens (3.2%) but not in cell lines. All thyroid carcinoma cell lines were significantly less sensitive (IC(50) at least 25-fold higher) in vitro to AEE788 than a primary culture of EGFR-mutant lung carcinoma cells.. Thyroid carcinoma cells overall are poorly responsive to clinically relevant concentrations of AEE788 in vitro. The presence of EGFR-activating TK domain mutations may identify a small minority of thyroid cancer patients that may benefit from EGFR inhibitors, but additional preclinical evidence of efficacy is needed.

Topics: Adolescent; Adult; Aged; Carcinoma; Cell Line, Tumor; ErbB Receptors; Female; Gene Expression Regulation, Neoplastic; Humans; Male; Middle Aged; Mutation; NF-kappa B; Oncogene Protein v-akt; Phosphorylation; Protein Structure, Tertiary; Purines; Reverse Transcriptase Polymerase Chain Reaction; RNA, Messenger; Sequence Analysis, DNA; Thyroid Neoplasms

Anaplastic thyroid carcinoma (ATC) is one of the most aggressive human malignancies with a mean survival of only 6 months. The poor prognosis of patients with ATC reflects the current lack of curative therapeutic options and the need for development of novel therapeutic strategies. In this study, we report the results of a preclinical study of AEE788, a dual inhibitor of epidermal growth factor receptor (EGFR) and vascular endothelial growth factor receptor (VEGFR) tyrosine kinases, against ATC. AEE788 was able to inhibit the proliferation and induce apoptosis of ATC cell lines in vitro. Administration of AEE788, alone and in combination with paclitaxel, to athymic nude mice bearing s.c. ATC xenografts inhibited the growth of ATC xenografts by 44% and 69%, respectively, compared with the control group. Furthermore, tumors from mice treated with AEE788, alone and in combination with paclitaxel, showed increase in apoptosis of tumor cells by approximately 6- and 8-fold, respectively, compared with the control group. The microvessel density within the ATC xenografts was decreased by >80% in the mice treated with AEE788 alone and in combination with paclitaxel compared with the control group. Lastly, immunofluorescence microscopy showed the inhibition of EGFR autophosphorylation on the tumor cells as well as the inhibition of VEGFR-2 autophosphorylation on tumor endothelium. Considering the fact that curative options seldom exist for patients with ATC, concurrent inhibition of EGFR and VEGFR tyrosine kinases seems to be a valid and promising anticancer strategy for these patients.

Topics: Animals; Antineoplastic Agents; Apoptosis; Blotting, Western; Carcinoma; Cell Death; Cell Proliferation; Dose-Response Relationship, Drug; Endothelium, Vascular; ErbB Receptors; Humans; Immunohistochemistry; Male; Mice; Mice, Nude; Microcirculation; Microscopy, Fluorescence; Neoplasm Transplantation; Paclitaxel; Phosphorylation; Purines; Receptors, Vascular Endothelial Growth Factor; Thyroid Neoplasms; Time Factors

Patients suffering from bone metastases of follicular thyroid carcinoma (FTC) have a poor prognosis because of the lack of effective treatment strategies. The overexpression of epidermal growth factor receptor (EGFR) associated with increased vascularity has been implicated in the pathogenesis of FTC and subsequent bone metastases. We hypothesized that inhibiting the phosphorylation of the EGFR and vascular endothelial growth factor receptor (VEGFR) by AEE788, a dual tyrosine kinase inhibitor of EGFR and VEGFR, in combination with paclitaxel would inhibit experimental FTC bone lesions and preserve bone structure. We tested this hypothesis using the human WRO FTC cell line. In culture, AEE788 inhibited the EGF-mediated phosphorylation of EGFR, VEGFR2, mitogen-activated protein kinase, and Akt in culture. AEE788, alone and in combination with paclitaxel, inhibited cell growth and induced apoptosis. When WRO cells were injected into the tibia of nude mice, tumor and endothelial cells within the lesions expressed phosphorylated EGFR, VEGFR, Akt, and mitogen-activated protein kinase that were inhibited by the oral administration of AEE788. Therapy consisting of orally given AEE788 and i.p. injected paclitaxel induced a high level of apoptosis in tumor-associated endothelial cells and tumor cells with the inhibition of tumor growth in the bone and the preservation of bone structure. Collectively, these data show that blocking the phosphorylation of EGFR and VEGFR with AEE788 combined with paclitaxel can significantly inhibit experimental human FTC in the bone of nude mice.

Topics: Adenocarcinoma, Follicular; Animals; Antineoplastic Combined Chemotherapy Protocols; Apoptosis; Bone Neoplasms; Cell Proliferation; Drug Synergism; ErbB Receptors; Humans; Male; Mice; Mice, Nude; Mitogen-Activated Protein Kinases; Neovascularization, Pathologic; Paclitaxel; Phosphorylation; Polymerase Chain Reaction; Protein Serine-Threonine Kinases; Proto-Oncogene Proteins; Proto-Oncogene Proteins c-akt; Purines; Receptors, Vascular Endothelial Growth Factor; Thyroid Neoplasms; Vascular Endothelial Growth Factor Receptor-2