Mechanisms of invasion in thyroid cancer remain poorly understood. We hypothesized that signaling via the epidermal growth factor receptor (EGFR) stimulates thyroid cancer cell invasion by altering the expression and cleavage of matrix metalloproteinases (MMPs). Papillary and follicular carcinoma cell lines were treated with EGF, the EGFR tyrosine kinase inhibitor AG1478, and the MMP inhibitors GM-6001 and Col-3. Flow cytometry was used to detect EGFR. In vitro invasion assays, gelatin zymography, and quantitative reverse transcription-PCR were used to assess the changes in invasive behavior and MMP expression and activation. All cell lines were found to overexpress functional EGFR. EGF stimulated invasion by thyroid cancer cells up to sevenfold (P < 0.0001), a process that was antagonized completely by AG1478 and Col-3, partially by GM-6001, but not by the serine protease inhibitor aprotinin. EGF upregulated expression of MMP-9 (2.64- to 8.89-fold, P < 0.0001) and membrane type-1 MMP (MT1-MMP, 1.97- to 2.67-fold, P < 0.0001). This effect was blocked completely by AG1478 and partially by Col-3. The activation of MMP-2 paralleled MT1-MMP expression. We demonstrate that MMPs are critical effectors of invasion in the papillary and follicular thyroid cancer cell lines studied. Invasion is regulated by signaling through EGFR, an effect mediated by augmentation of gelatinase expression and activation. MMP inhibitors and growth factor antagonists may be effective tumoristatic agents for the treatment of aggressive thyroid carcinomas.
Michael W Yeh, Jean-Philippe Rougier, Jin-Woo Park, Quan-Yang Duh, Mariwil Wong, Zena Werb and Orlo H Clark
Laetitia Dahan, Frank Bonnetain, Philippe Rougier, Jean-Luc Raoul, Eric Gamelin, Pierre-Luc Etienne, Guillaume Cadiot, Emmanuel Mitry, Denis Smith, Frédérique Cvitkovic, Bruno Coudert, Floriane Ricard, Laurent Bedenne, Jean-François Seitz and for the Fédération Francophone de Cancérologie Digestive (FFCD) and the Digestive Tumors Group of the Fédération Nationale des Centres de Lutte Contre le Cancer (FNCLCC)
The aim of this randomized multicenter phase III trial was to compare chemotherapy and interferon (IFN) in patients with metastatic carcinoid tumors. Patients with documented progressive, unresectable, metastatic carcinoid tumors were randomized between 5-fluorouracil plus streptozotocin (day 1–5) and recombinant IFN-α-2a (3 MU×3 per week). Primary endpoint was progression-free survival (PFS). From February 1998 to June 2004, 64 patients were included. The two arms were well matched for median age, sex ratio, PS 0–1, previous chemotherapy, surgery, or radiotherapy. The median PFS for chemotherapy was 5.5 months versus 14.1 for IFN (hazard ratio=0.75 (0.41–1.36)). Overall survival (OS), tolerance, and effects on carcinoid symptoms were not significantly different. Despite a trend in favor of IFN, there was no difference in PFS and OS in advanced metastatic carcinoid tumors and therapeutic effect of both treatments was mild.