Zhu et al. Journal of Experimental & Clinical Cancer Research 2010, 29:124 http://www.jeccr.com/content/29/1/124 R E S E A R C H Open Access The proliferation, apoptosis, invasion of endothelial-like epithelial ovarian cancer cells induced by hypoxia Pengfei Zhu1,2, Yanxia Ning3, Liangqing Yao1*, Mo Chen1, Congjian Xu1 Abstract Background: Epithelial ovarian cancer is one of the most malignant cancers in women because metastasis occurs in the most of patients by the time of diagnosis. Cancer cells have strong capacity to form angiogenesis or vasculogenic mimicry, which plays the major role in its malignant phenotype. Vasculogenic mimicry might contribute to the failure of the angiogenesis-targeted therapy strategies. Under the microenvironment of the tumor, hypoxia is the most common phenomena because of the vast energy and oxygen consuming. In the present study, the endothelial-like cells induced by hypoxia from SKOV-3 and ES-2 ovarian cancer cells were harvested to investigate the changes in their biological behaviors. Methods: The endothelial-like cells from SKOV-3 and ES-2 cells were harvested by laser capture microdissection. The biological behaviors of the endothelial-like cells, including proliferation, cell cycle, apoptosis, invasion and telomerase activity were determined by MTT, FCM, Transwell chamber and TRAP-ELISA methods. HIF-1a is the most important factor for the behavior changes under hypoxic condition. Some other genes relative to biological behaviors are also changes following the changes of HIF-1a. In order to elucidate the underlying mechanisms for these changes by hypoxia, the relative genes expressions including HIF-1a, CyclinD1, Flk-1, VEGF, p53 and V-src were determined by real-time PCR. Results: SKOV-3 and ES-2 cells were resistant to hypoxia by adoption of proliferation, apoptosis, differentiation and invasion. Combined with other studies, the more poorly cancer cells differentiate, the more strongly cells are resistant to hypoxia, the more possible to form vasculogenic mimicry. The changes in the expression of HIF-1a, and HIF-1a-dependent VEGF, Flk-1, Cyclin D1, and HIF-1a-independent p53 have been involved in this process. Conclusions: HIF-1a took an important role in the behavioral changes of SKOV-3 and ES-2 cells by hypoxia. At the same time, other mechanisms were also involved in this process. Background Epithelial ovarian cancer (EOC) has the ~50% mortality rate, making it the leading cause of death from gyneco- logical cancers [1,2]. In most patients, metastasis occurs within the peritoneum by the time of diagnosis. Although the cellular and molecular mechanisms of tumor growth and metastasis are not completely under- stood, it is established that formation and growth of new blood vessels is critical for tumor survival, growth, and expansion [3]. Numerous studies have demonstrated * Correspondence: yaoliangqingcn@126.com 1Department of Gynecology, Obstetrics & Gynecology Hospital, Fudan University, 419 Fangxie Rd, Shanghai, 200011, China Full list of author information is available at the end of the article that the more vasculogenesis, the more malignant of the tumors. Thus, efforts to reduce the growth and spread of ovarian cancer have recently focused on angiogenesis because they are dependent in part on the formation of adequate vascular support [4], which means forming or sprouting of new endothelium-lined vessels from pre- existing vessels [5]. The traditionally recognized mechanism for tumor vasculature and perfusion has been thought to be endothelial cells-lined vascular networks [6]. However, recent study has found that some aggressive tumor cells generate vasculogenic-like channels in the absence of endothelial cells or fibroblasts [7]. The formation of the patterned microcirculation is termed vasculogenic © 2010 Zhu et al; licensee BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License ( http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.