Abstract 4229: Wound repair promotes ovarian cancer stem cell self-renewal

Abstract

Background: In normal tissues following injury, there is an expansion of tissue specific stem cells prior to their differentiation to initiate injury repair. Once the tissue is repaired, the stem cells return to a quiescent state. Tumor tissue, might follow similar characteristics as in normal tissues, but the control of the expansion process may be significantly altered. Recently, ovarian cancer stem cells (ovCSC) were isolated from ovarian cancer tissue and ascites using CD44/CK18 as markers. We hypothesize that these cells play a critical role in tumor repair and renewal. To test this hypothesis, we used an in vitro wound/healing system. Methods: Cells were plated in an Essen ImageLock plate and wounds were made using an Essen WoundMaker. This sytem allows the generation of consistent wound locations and widths and precise imaging of the wound area. The healing process is monitored using an insitu imaging system (IncuCyte, Essen Instruments, NH) that records and quantifies the repair process in real time. Levels of cancer stem cell markers, CD44, Oct-4, and β-catenin were determined by Western blot analysis or Real Time PCR. Levels of cytokines and chemokines were determined using Luminex Technology. Results: Initially we tested whether an in vitro wound/healing system can be used as a renewal model. Interestingly, ovCSCs showed a well coordinated and organized response to the wound. First, the cells created a “straight line” to replace the irregular edge of the wound. Afterwards, the cells proliferated towards the wound, repairing the wound until confluence was reached. Analysis of cancer stem cell markers by Western blot revealed that the cells which repaired the wound maintained CD44, CK18, Oct4, and β-catenin, previously shown as ovCSC markers. Additionally, the process of repair was characterized by significant and differential up-regulation in IL-6, GRO-α, and MCP-1 expression and secretion. Interestingly, the CD44 expression was increased in wounded wells when compared to control. Moreover, using specific primers for CD44 variant isoforms we found that wound healing promotes expression of different CD44 forms. Conclusions: In this study we demonstrate ovCSCs have the capacity to repair an in vitro wound and that this process is accompanied by increased CD44 expression and cytokine secretion. This increased capacity of self renewal can lead to the accumulation of a large pool of progenitor cells, which has the potential to individually spread to other areas of the body as metastatic cells. 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 4229.