Abstract 4309: Isolation, expansion and molecular characterization of lung cancer stem cells from NSCLC cell lines

Abstract Lung cancer is the leading cause of death from cancer worldwide. NSCLC represents the most common subtype of lung cancer with the average five-year survival rate is only 16%. The majorities of these tumors are refractory to chemotherapeutics or acquire resistance to the therapy. In addition, most of the patients develop distant metastases even tough their primary tumors are surgically removed. Cancer stem cell hypothesis has emerged as a possible explanation for tumor growth, recurrence after treatment and metastasis in a variety of cancer. This hypothesis suggests that tumors are maintained by the subset of cancer stem cells (CSCs) that has the ability to self-renew and generate the diverse cells that comprise the tumor. While evidence supporting the existence of CSCs has been demonstrated in many solid cancers, it is largely underdeveloped in lung cancer. Here we have isolated cancer stem like cells from NSCLC cell lines either through isolating the side population (SP) cells based on their property to exclude Hoechst 33342 dye or enriched them by cultivating cancer cells in defined serum free medium containing N2-supplement, EGF and bFGF. Cells obtained from both these methods demonstrated higher clonogenic as well as sphere forming ability which is the typical characteristics associated with CSCs. We further characterized these cells for their ability to express progenitor/stem cell marker genes like Oct4, Sox2 and Nanog. Total RNA from SP cells showed higher expression of these genes as compared to main population. Similarly, the expression of Oct4, Sox2 and Nanog was found elevated after culturing H1650, H358, H322 and H292 cells in defined serum free medium for 10 days. Interestingly, CSCs enriched in this condition also showed the loss of E-cadherin expression and consequent gain of mesenchymal proteins like fibronectin and vimentin. Additionally, ABCG2, which is closely associated with the drug resistance and responsible for side population phenotype, was also upregulated in cancer stem like cells enriched from culturing in serum free defined media. In conclusion, results revealed that lung cancer stem like cells could be isolated and expanded from the established lung cancer cell lines by two different methodologies described here. These cells possess the characteristics of both stem cells and malignant tumors. Therefore, further studies towards targeting these cells may result in effective therapy against lung cancer. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 4309.