Introduction: Cancer Stem Cells (CSCs) are thought to possess tumor initiation and self-renewal and are associated with tumor progression. The niche cells of microenvironment, such as fibroblast might play an important role for the progression of cancer cells. The aim of this study is to examine the effect of cancer-associated fibroblasts on the stemness of CSCs. Material and Methods: A gastric cancer cell line, OCUM-12, and cancer-associated gastric fibroblast, CaF-37, were used. SP cells, known as CSCs rich population, were isolated from OCUM-12 cells by flowcytometry using Hoechest33342, and were named as OCUM-12/SP. The percentage of SP cells was evaluated by flowcytometry, after it was cultured with condition medium from CaF-37 for three days. SP fraction was evaluated by flowcytometry, in the presence or absence of TGF-β receptor inhibitor, FGF receptor inhibitor, and c-Met Receptor inhibitor. In vivo, tumorigenicity of OCUM-12/SP cells were evaluated by subcutaneous inoculation in the presence or abcence of CaF-37. Results: The inoculation of 1.5x105, 5x104, and 1.5x104 OCUM-12/SP cells with 5x105 CaF-37 fibroblasts resulted in tumor formation in all of mice, respectively. However, the inoculation of 1.5x105, 5x104, and 1.5x104 OCUM-12/SP cells alone results in poor tumor formation at 3(60%) of 5 mice, 0(0%) of 5 mice and 0(0%) of 5 mice, respectively. The percentage of SP fraction of OCUM-12/SP was significantly increased in the presence of condition medium from CaF-37. The increase of SP fraction of OCUM-12/SP cells by condition medium from CaF-37 was inhibited by TGF-β receptor inhibitor, but not FGF receptor inhibitor and c-Met inhibitor. Conclusion: TGF-β from the niche, fibroblasts, might sustain the stemness of CSCs and might be associated with the progression of Cancer Cells.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 3337. doi:1538-7445.AM2012-3337