Dual targeting of EGFR and HER-2 in colon cancer cell lines.
ABSTRACT A number of studies have revealed that coexpression of EGFR and HER-2 has been found in a subset of colon cancers and may cooperatively promote tumor cell growth and survival. In the present work, two tyrosine kinase inhibitors, gefitinib and lapatinib, together with trastuzumab, raised a monoclonal antibody against HER-2 were evaluated in two colon cancer cell lines, DLD-1 and Caco-2. The aim of the study was to investigate their effect on tumor cell proliferation and apoptosis.
Cell proliferation was assessed using the MTT assay and apoptosis was evaluated by DNA fragmentation and the Annexin V binding assay. EGFR and HER-2 protein and mRNA levels were evaluated by immunoblotting and quantitative RT-PCR, respectively.
Treatment of cells with each agent alone resulted in inhibition of cell proliferation after 48 h in a dose-dependent manner except for trastuzumab, which did not alter cell proliferation of DLD-1. Apoptosis increased in DLD-1 cells, after 24 h treatment with gefitinib. None of the tested agents altered apoptosis in Caco-2 cells. HER-2 and EGFR protein levels did not follow the changes of mRNA levels after treatment with the tested agents.
Tauhe inhibitory effect of these agents on cell proliferation and the induction of apoptosis differ for the two colon cancer cell lines under consideration. Further studies are necessary to investigate the way they exert their antitumor effect.
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ABSTRACT: Recent evidence suggests that estrogen signaling may be involved in the pathogenesis of non-small cell lung cancer (NSCLC). Aromatase is an enzyme complex that catalyses the final step in estrogen synthesis and is present in several tissues, including the lung. In the current study we investigated the activity of the aromatase inhibitor exemestane in human NSCLC cell lines H23 and A549. Aromatase expression was detected in both cell lines. H23 cells showed lower protein and mRNA levels of aromatase, compared to A549 cells. Exemestane decreased cell proliferation and increased apoptosis in both cell lines, 48 h after its application, with A549 exhibiting higher sensitivity than H23 cells. Aromatase protein and mRNA levels were not affected by exemestane in A549 cells, whereas an increase in both protein and mRNA levels was observed in H23 cells, 48 h after exemestane application. Moreover, an increase in cAMP levels was found in both cell lines, 15 min after the administration of exemestane. In addition, we studied the effect of exemestane on epidermal growth factor receptor (EGFR) localization and activation. Exemestane increased EGFR activation 15 min after its application in H23 cells. Furthermore, we demonstrated a translocation of EGFR from cell membrane, 24 h after the addition of exemestane in H23 cells. No changes in EGFR activation or localization were observed in A549 cells. Our findings suggest an antiproliferative effect of exemestane on NSCLC cell lines. Exemestane may be more effective in cells with higher aromatase levels. Further studies are needed to assess the activity of exemestane in NSCLC.Molecular Cancer 11/2009; 8:109. · 3.99 Impact Factor