Abstract 2531: Marker free isolation and expansion of cancer stem cells from small cell lung cancer

Small cell lung cancer (SCLC) accounts for approximately 15% of all lung cancer cases and, contrary to the advances in diagnostics and therapeutic options for non small cell lung cancer, SCLC long term survival has failed to materially improve over the last 3 decades. Early dissemination with hematogenous metastasis, advanced stages at diagnosis, dramatic response to chemotherapy with early and aggressive relapses are the clinical hallmarks. Limited surgical samples, early palliation and limited second line treatment options negating the benefit of repeat biopsies have limited tissue available for research to understand the biology of this relatively rare tumor. Recent data has suggested the presence of rare populations of cells within the primary SCLC tumors which have stem cell-like properties. We hypothesize that novel in vitro culture platforms and methods can be used to isolate and expand cancer stem cells (CSCs) within SCLC tumors and that the expanded CSCs will yield a renewable cell source for research applications and for predictive drug response profiling. Many groups have relied upon cell surface markers such as CD133 and CD24 to identify the CSC population. Our approach is unique in that we have employed a marker-free approach utilizing a combination of chemical and functional isolation. We then use a combination of growth factors, extracellular matrix proteins, and oxygen tension in a 3D perfusion culture system to further isolate, purify and expand isolated cells with the goal of having quantities of functional SCLC stem cells for molecular, proteomic and functional in vitro and in vivo assays. Initial cell sources will include immortalized cell lines and patient derived xenograft lines, with eventual adaptation to primary patient samples. Using numerous techniques, we have qualified these cells based upon marker expression (flow cytometry, RT-PCR), dye exclusion, drug response, and limited dilution assays. Future experiments will confirm stemness with limited dilution tumorigenicity assays in vivo. Initial data suggest poor correlation of canonical CSC marker expression with clonogenic growth in cell lines, supporting the need for unbiased and functional isolation methods. These expanded populations of CSCs may be used to identify novel CSC markers and/or targets, mechanisms of resistance and screen and develop novel therapeutics Our ultimate goals are to be able to use our novel culture platforms and methods to expand CSCs for real time precision medicine applications to identify novel therapies in real time that can eradicate the CSC population and improve outcomes of patients with SCLC. Citation Format: Tessa M. DesRochers, Melissa Millard, Alina Lotstein, Lillia Holmes, Hal E. Crosswell. Marker free isolation and expansion of cancer stem cells from small cell lung cancer. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 2531.