Abstract 374: KDR amplification in NSCLC is associated with sensitivity to VEGFR tyrosine kinase inhibitors.

Abstract

Abstract Targeted therapies designed to inhibit the vascular endothelial growth factor (VEGF) pathway have been extensively evaluated in the treatment of malignancies including Non-Small Cell Lung Cancer (NSCLC). VEGF pathway inhibitors such as bevacizumab, or the multitargeted receptor tyrosine kinase inhibitors (TKIs) vandetanib and sorafenib, have been shown to prolong progression-free survival (PFS) and/or overall survival (OS). These benefits, however, have been modest, seen only in subsets of patients. Thus, predictive markers for identifying which patients are likely to benefit are critically needed. Although expression of VEGF receptor-2 (VEGFR-2, also known as KDR) was initially thought to primarily occur in endothelial cells, VEGFR-2 has been detected on malignant cells, including lung cancer cells, and in NSCLC, overexpression of VEGFR-2 on tumor cells is associated with a poor clinical outcome. Amplification of KDR has been detected in lung cancer specimens at a relatively high frequency (9% and 32%). The consequences of KDR copy number gains (CNGs) are not yet understood. Recently, we have shown that NSCLC cell lines with KDR copy number gains (CNGs) were associated with in vitro resistance to platinum chemotherapy, and KDR CNG predicted worse overall survival in patients who received platinum adjuvant therapy but not in untreated patients. We investigated the hypothesis that NSCLC tumor cells with KDR CNG display increased sensitivity to VEGFR TKIs compared to tumor cells without KDR CNG. In tumor cell lines with KDR CNG, treatment with exogenous VEGF ligand enhanced cell motility and this was inhibited by VEGFR blockade with TKIs. Multiple receptor tyrosine kinases have been shown to drive HIF-1α levels, and NSCLC cells with KDR CNG express elevated levels of HIF-1α in normoxic conditions compared to NSCLC cell lines without KDR CNG. Here, we show that in NSCLC cell lines with KDR CNG, VEGFR TKIs decreased protein levels of HIF-1α and HIF-1α- regulated proteins. Furthermore, we report a clinical case in which a NSCLC patient with KDR CNG as determined by SNP array had a partial response to VEGFR inhibition with sorafenib. Citation Format: Monique B. Nilsson, Tina Cascone, Jayanthi Gudikote, Emily Roarty, Lixia Diao, Andrew Koo, Sumankalai Ramachandran, Erick Riquelme, Hai Tran, Ignacio Wistuba, David P. Carbone, John Heymach. KDR amplification in NSCLC is associated with sensitivity to VEGFR tyrosine kinase inhibitors. [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 374. doi:10.1158/1538-7445.AM2013-374