Abstract 4972: Analysis of the reprogrammed bone marrow-derived stroma in lung cancer unravels potential targets for prognosis and therapy

Background: Lung cancer is the leading cause of cancer related mortality, with NSCLC the most prevalent form. Despite advances in treatment options (minimally invasive surgery, CT-guided radiation, novel chemotherapy regimens, targeted therapeutics) prognosis remains dismal. Most research to date has focused on cancer cell intrinsic mutagenesis (K-ras, p53, EGFR, EML4-ALK fusion), however recent studies have begun to recognize that cross talk between tumor epithelial cells and intratumoral stromal cells contributes to tumor progression. Unfortunately, little is known about the contribution or role of the stroma in NSCLC. Here, we present the first comprehensive analysis of specific individual stromal components of human NSCLC, which has led to the identification of stromal-specific activated pro-tumorigenic genes of prognostic and therapeutic potential. Materials and Methods: Surgically resected Stage I/II adenocarcinoma and matched adjacent non-neoplastic lung tissue were mechanically dissociated within 1hour of resection. Cell populations marked with specific antibodies were sorted to homogeneity by flow cytometry. RNA was isolated to construct cDNA libraries, which were deep sequenced using the Illumina HiSeq 2000. Validation of differentially regulated genes was carried out by RT-PCR and immunostaining. Mouse models of K-rasG12D and p53flox/flox derived NSCLC together with a bone marrow transplantation approach were used to determine the functional role of activated genes, and a NSCLC tissue microarray was used to ascertain their prognostic value. Results: Flow cytometry analysis revealed a 4-fold increase in the number of intratumoral hematopoietic cells, compared with adjacent non-neoplastic lung tissue. Deep RNA sequencing of two predominant myeloid specific subpopulations, CD11b+CD33+ monocytic myeloid cells and CD11b+CD33- polymorphonuclear neutrophils, revealed 783 and 938 differentially regulated genes respectively when comparing tumor vs. adjacent lung-derived cells. Many genes encoded secreted proteins such as OPN, TSP1, CCL7, and MMP12, suggesting activation of aberrant autocrine and paracrine regulatory pathways likely to support stromal-mediated tumor progression. We will present data showing the prognostic and therapeutic potential of these genes in NSCLC. Conclusions: This study is based on an emerging paradigm that activated intratumoral stromal cells play a fundamental role in promoting tumor growth. Using a unique and novel approach of quantitative analysis of individual stromal components from freshly procured NSCLC tumor tissue, we have identified differentially regulated genes previously undiscovered in traditional whole tumor profiling approaches. The activated stromal genes constitute novel therapeutic targets against lung cancer, either alone or in combination with treatments that target cancer cells. Citation Format: Anna Durrans, Dingcheng Gao, Ravi Gupta, Seongho Ryu, Navneet Narula, Kari R. Fischer, Hyejin Choi, Brendon M. Stiles, Abu Nasar, Ramana V. Davuluri, Nasser K. Altorki, Vivek Mittal. Analysis of the reprogrammed bone marrow-derived stroma in lung cancer unravels potential targets for prognosis and therapy. [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 4972. doi:10.1158/1538-7445.AM2013-4972