Antitumor and antiangiogenic effect of the dual EGFR and HER-2 tyrosine kinase inhibitor lapatinib in a lung cancer model

Roque Diaz,Ricardo Parrondo,Maria Collantes,Alfonso Calvo,Paul A Nguewa,Juan Antonio Díaz-González,Ivan Peñuelas,Carlos Perez-Stable,Miriam Redrado,Raul Catena,Irene Manrique

doi:10.1186/1471-2407-10-188

Abstract

BackgroundThere is strong evidence demonstrating that activation of epidermal growth factor receptors (EGFRs) leads to tumor growth, progression, invasion and metastasis. Erlotinib and gefitinib, two EGFR-targeted agents, have been shown to be relevant drugs for lung cancer treatment. Recent studies demonstrate that lapatinib, a dual tyrosine kinase inhibitor of EGFR and HER-2 receptors, is clinically effective against HER-2-overexpressing metastatic breast cancer. In this report, we investigated the activity of lapatinib against non-small cell lung cancer (NSCLC).MethodsWe selected the lung cancer cell line A549, which harbors genomic amplification of EGFR and HER-2. Proliferation, cell cycle analysis, clonogenic assays, and signaling cascade analyses (by western blot) were performed in vitro. In vivo experiments with A549 cells xenotransplanted into nude mice treated with lapatinib (with or without radiotherapy) were also carried out.ResultsLapatinib dramatically reduced cell proliferation (P < 0.0001), DNA synthesis (P < 0.006), and colony formation capacity (P < 0.0001) in A549 cells in vitro. Furthermore, lapatinib induced G1 cell cycle arrest (P < 0.0001) and apoptotic cell death (P < 0.0006) and reduced cyclin A and B1 levels, which are regulators of S and G2/M cell cycle stages, respectively. Stimulation of apoptosis in lapatinib-treated A549 cells was correlated with increased cleaved PARP, active caspase-3, and proapoptotic Bak-1 levels, and reduction in the antiapoptic IAP-2 and Bcl-xL protein levels. We also demonstrate that lapatinib altered EGFR/HER-2 signaling pathways reducing p-EGFR, p-HER-2, p-ERK1/2, p-AKT, c-Myc and PCNA levels. In vivo experiments revealed that A549 tumor-bearing mice treated with lapatinib had significantly less active tumors (as assessed by PET analysis) (P < 0.04) and smaller in size than controls. In addition, tumors from lapatinib-treated mice showed a dramatic reduction in angiogenesis (P < 0.0001).ConclusionOverall, these data suggest that lapatinib may be a clinically useful agent for the treatment of lung cancer.

Highlights

There is strong evidence demonstrating that activation of epidermal growth factor receptors (EGFRs) leads to tumor growth, progression, invasion and metastasis
HER-2 gene amplification in A549 cells Previous studies have shown that A549 cells harbor EGFR gene amplification [7], but the HER-2 status of these cells was unknown
We determined whether the HER-2 gene is amplified in A549 cells

Summary

Introduction

There is strong evidence demonstrating that activation of epidermal growth factor receptors (EGFRs) leads to tumor growth, progression, invasion and metastasis. Two EGFR-targeted agents, have been shown to be relevant drugs for lung cancer treatment. Recent studies demonstrate that lapatinib, a dual tyrosine kinase inhibitor of EGFR and HER-2 receptors, is clinically effective against HER-2-overexpressing metastatic breast cancer. Since activation of epidermal growth factor receptor (EGFR) promotes mechanisms leading to tumor growth and progression, EGFR-targeted agents are being widely explored. Previous clinical trials have demonstrated that both EGFR and HER-2 genes are amplified in lung cancer, resulting in the overexpression of these proteins [1,2]. Such overexpression significantly correlates with gene amplification [6]. Lung tumors with high levels of both EGFR and HER-2 may be appropriate for treatment with lapatinib

Methods

Results

Conclusion