Abstract 1420: Mechanisms of stroma-derived CCL7 in promoting lung cancer.

Abstract

Abstract Lung cancer is a leading cause of cancer related deaths worldwide, with non-small cell lung cancer (NSCLC) being the most prevalent form. Considerable attention has been directed to cancer cell intrinsic abnormalities (K-ras, p53, EGFR, AML-ALK4 fusions etc.), but little is known about the contribution of stromal cells to NSCLC progression. We have undertaken a comprehensive analysis to determine the contribution and biological function of the stromal cells in NSCLC. We show increased recruitment of BM hematopoietic cells in the tumor beds compared to matched adjacent non-neoplastic lung tissue in NSCLC patients. Genome-wide transcriptome analysis on specific cell populations from fresh samples of NSCLC patients identified differentially regulated genes and mRNA isoforms in NSCLC stromal cells. Genes that were successfully validated by independent RT-PCR on sorted stromal cells and tumor cells were used for further analysis. Many genes encoded secreted proteins, suggesting the activation of aberrant autocrine and paracrine regulatory loops likely to support stroma-mediated tumor progression. Among these genes, CCL7 was upregulated in myeloid progenitor cells and was selected for further investigation. Immunostaining of lung tumor and adjacent non-neoplastic tissue of patients shows highest expression of CCL7 in BM-derived cells (CD45+ cells) in the tumor. Cross species analysis showed that, consistent with the observation in human tissue, CCL7 was differentially regulated in BM derived cells in a mouse model of NSCLC generated in KrasG12D and p53-/- transgenic mice. We have genetically ablated CCL7 in the BM cells using lentiviral shRNA and BMT approaches and will discuss consequences of this ablation in CCL7-mediated crosstalk between tumor cells and stromal cells that regulate NSCLC progression. Citation Format: Hyejin Choi, Anna Durrans, Dingcheng Gao, Seongho Ryu, Nasser Altorki, Vivek Mittal. Mechanisms of stroma-derived CCL7 in promoting lung cancer. [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 1420. doi:10.1158/1538-7445.AM2013-1420