Abstract 2385: Identification of a molecular marker for cetuximab sensitivity and development of a novel combination therapy for non-small cell lung cancers.

Abstract

Abstract The epidermal growth factor receptor (EGFR) is an important molecular target for non-small-cell lung cancers (NSCLCs). A recent phase III study (the FLEX study) revealed that the combination of the anti-EGFR antibody cetuximab with conventional chemotherapy improved the survival of patients with NSCLCs. However, the survival benefit was only about 5 weeks. Therefore, the identification of a molecular marker for cetuximab sensitivity is urgently needed. In this study, we investigated a new molecular marker for cetuximab sensitivity and developed a combination therapy to improve the effectiveness of cetuximab. First, we established a NSCLC cell line that showed resistance to cetuximab by culturing a parental sensitive NSCLC cell line in the presence of increasing concentrations of cetuximab. Next, we performed microarray analysis to compare the gene expression patterns of cetuximab-sensitive and -resistant cell lines. Using pathway analysis, we found that the Akt and Wnt pathways were significantly activated in the resistant cell line as compared to their activation in the sensitive cell line. We confirmed this result by performing western blot analysis, which showed Akt phosphorylation and beta-catenin dephosphorylation in the resistant cell line. Therefore, the activation status of either the Akt or Wnt pathway is the candidate pathway that influences cetuximab sensitivity. Finally, we focused on the Akt pathway and treated both resistant and parental sensitive cell lines with the PI3-K inhibitor LY294002 in combination with cetuximab. This combination therapy induced a synergistic growth-inhibiting effect in both cell lines. The data suggest that the activation status of the Akt pathway is one of the markers for cetuximab sensitivity and the combination of an Akt pathway inhibitor and cetuximab would be a promising anti-EGFR therapy for NSCLCs. Citation Format: Miyako Takata, Hiroki Chikumi, Kosuke Yamaguchi, Jun Kurai, Masaki Nakamoto, Naoto Burioka, Tadashi Igishi, Eiji Shimizu. Identification of a molecular marker for cetuximab sensitivity and development of a novel combination therapy for non-small cell lung cancers. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 2385. doi:10.1158/1538-7445.AM2013-2385 Note: This abstract was not presented at the AACR Annual Meeting 2013 because the presenter was unable to attend.