Abstract 3355: Comparison of CD133, uPAR, and CXCR4 expression in lung cancer cell lines under normal and spheroid culture conditions

Abstract

Abstract Background: Cancer stem cells (CSC) have been identified in several solid tumors including breast, brain, and recently lung cancers, etc. In the CSC model, CSCs are thought to be able to self-renew extensively, grow as spheroids in vitro, and be resistant to conventional cancer therapies. CD133, uPAR and CXCR4 have been reported as putative markers that can be used to mark enriched cancer stem cell populations. Although CD133, uPAR and CXCR4 have been implicated in CSC biology and identification, their application as lung CSC (LCSC) markers have not been fully explored. In this study we examined and compared CD133, uPAR and CXCR4 expression in non-spheroid cells and CSC-like spheroid cells derived from several lung and non-lung cancer cell lines. Methods: We cultured four classic small cell lung cancer (SCLC) lines, two variant SCLC lines, three non-small cell lung cancer (NSCLC) lines, one primary lung cancer line derived in our lab, three lymphoma cell lines, one thymoma cell line, and one breast cancer cell line. Cell lines were maintained in RPMI or DMEM with 10% fetal calf serum. Spheroids were cultured and maintained in low-attachment flasks in serum free media supplemented with EGF and FGF. CD133, CXCR4, and uPAR expression were evaluated by immunostaining followed by flow cytometry analysis. Results: Under spheroid culture conditions, CD133 expression tends to remain the same or increases in most of the cell lines tested. SCLC and lymphoma lines tend to express more CD133 than NSCLC and non-lung cancer lines in both normal and spheroid culture conditions. uPAR expression is generally low, however when detectable, it only shows up in cell lines grown in spheroid culture conditions. CXCR4 expression generally increases in spheroid culture conditions with greater expression seen in SCLC lines and lymphoma lines. Conclusion: Spheroid cells tend to exhibit higher CD133 expression than cells under regular culture conditions. This finding supports the idea that CD133 is enriched in LCSC populations. SCLC and lymphoma lines in normal and spheroid culture conditions express more CD133, uPAR, and CXCR4. This does not appear to be tied to adherent growth properties as two adherent SCLC lines displayed no striking difference in expression compared with other non-adherent SCLC lines. However the tendency for SCLC cells and lymphoma cells to grow in regular culture conditions as clumps may offer some insight into the increased expression of these markers. 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 3355.