Contribution Of Fibroblasts Isolated From Primary Lung Cancers And Normal Lung Tissue To Tumor Growth

Proceedings: AACR 102nd Annual Meeting 2011‐‐ Apr 2‐6, 2011; Orlando, FL Fibroblasts isolated from cancer specimens have been shown to possess pro-tumorigenic properties, often associated with traits reminiscent of myofibroblasts found at sites of wound healing, but little is known about the mediators of the interaction between fibroblasts and cancer cells especially in lung cancer. To evaluate the contribution of fibroblasts to lung cancer development we established 60 fibroblast cultures from cancerous and normal lung tissue from primary lung cancer patients, including 18 pairs of normal (NF) and cancer-associated fibroblasts (CAF) from the same patient. The mesenchymal nature of the cultures was confirmed by expression of surface markers CD90, CD166, CD105 and CD73 and negativity for epithelial and hematopoietic markers (ESA and CD45). Further immunophenotyping with markers specific for fibroblasts subpopulations (FSP, vimentin, alpha-SMA, FAP) identified frequent expression of activation markers, with up to 50% of alpha-SMA+ cells. Interestingly activation properties were identified also in cultures derived from normal lung tissue. Co-mingling of fibroblasts (NF or CAF) with A549 lung cancer cells generally resulted in increased tumor size after injection in nude mice and 2/4 of the CAF cultures tested also increased tumor take when cancer cells were injected at low doses. Human cells were identified by HLA staining in the stroma of tumors grown after co-injection confirming the contribution of the mixed fibroblasts to tumor development. Furthermore medium conditioned by fibroblasts promoted growth of lung cancer cells or immortalized bronchial epithelial cells. All the cultures tested displayed a normal karyotype suggesting that the functional properties of fibroblasts are likely to be the result of epigenetic changes.These results indicate that lung fibroblasts might play a central role in the growth and progression of lung neoplasia. Consistently with their activated phenotype also cultures from normal lung tissue of heavy smokers displayed pro-tumorigenic activity, indicating that the microenvironment of lungs heavily exposed to damage from carcinogenic substances might already be predisposed to foster the growth of transformed epithelial cells. The full dissection of this complex picture might reveal mediators of the cross-talk between stroma and cancer cells and provide novel therapeutic targets. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 530. doi:10.1158/1538-7445.AM2011-530