Abstract 1159: A novel HGF-MET paracrine signaling pathway promotes growth and resistance to chemotherapy in lung cancer

Proceedings: AACR Annual Meeting 2014; April 5-9, 2014; San Diego, CA Lung cancer is a leading cause of deaths from cancer among men and women worldwide with an estimated 1.5 million deaths each year. Available molecularly targeted therapies benefit a limited number of patients and even in these patients acquired resistance is a major impediment to effective therapeutic response. To address the need for additional therapeutic targets, we used a unique approach to identify and target tumor-stroma paracrine crosstalk pathways in non-small cell lung cancer (NSCLC). To explore paracrine crosstalk in NSCLC, we analyzed transcriptomes of specific stromal and epithelial compartments that were sorted from Kras driven mouse model of NSCLC. Transcriptome analysis and computational modeling of multi-cellular network identified potential tumor-stroma crosstalk signaling pathways. We have selected the hepatocyte growth factor (HGF)-MET tyrosine kinase receptor signaling pathway because both HGF and MET are associated with poor survival in many cancer types including lung cancer. Notably, we identified reprogrammed intratumoral macrophages as unique source of HGF, while the expression of MET receptor was confined to tumor epithelial compartment. Importantly, we have observed elevated HGF in chemoresistant tumors both in mouse and human. Previous studies have implicated MET receptor amplification or mutations as the main mechanism of acquired resistance to EGFR TKIs, but little is known about the contribution of HGF ligand-dependent activation of MET signaling in NSCLC growth and resistance to chemotherapeutic regimens that are widely used. We have used a combination of culture experiments and in vivo genetic approaches to show that macrophage-derived HGF interacts with the MET receptor on tumor epithelial cells in a paracrine fashion, to activate downstream signaling pathways that promote tumor progression and mediate resistance to standard chemotherapies. Our investigations on this relatively unexplored HGF-MET paracrine interaction as a key mechanism of resistance to standard-of-care chemotherapeutic regimens-and not just EGFR targeted therapies-have the potential to benefit the NSCLC population as whole rather than a small subset of patients. Citation Format: Hyejin Choi, Ding Cheng Gao, Sharrell B. Lee, Anna Durrans, Seongho Ryu, Olivier Elemento, Stephen Wong, Nasser K. Altorki, Vivek Mittal. A novel HGF-MET paracrine signaling pathway promotes growth and resistance to chemotherapy in lung cancer. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 1159. doi:10.1158/1538-7445.AM2014-1159