Impact Of Transfected TIMP-2 Gene Into Cultured BTSC Upon The Biological Behavior Of BTSC

Brain tumors are typically comprised of morphologically diverse cells that express a variety of neural lineage markers. Study of brain tumors by traditional histopathology has only yielded a limited amount of knowledge of the clinical behavior of the tumor. It is recognized that tumors with vastly different histology have a different prognosis, but often brain tumors that share similar morphology and phenotype can have a very different prognosis and response to treatment. Brain tumors of the same histologic type can also have a very different behavior in patients of different ages. Although major advances have been made in the understanding of the molecular genetic alterations of some types of brain tumors (Maher et al., 2001; Wechsler-Reya and Scott, 2001; Zhu and Parada, 2002; Gilbertson, 2004), particularly medulloblastomas and malignant gliomas, and some of these identified alterations are now beginning to guide treatment, it is not clear whether all the tumor cells are equivalent in their ability to maintain the growth of the tumor. The cancer stem cell hypothesis suggests that not all the cells in the tumor have the same ability to proliferate and maintain the growth of the tumor. Only a relatively small fraction of cells in the tumor, termed cancer stem cells, possess the ability to proliferate and self-renew extensively. Most of the tumor cells lose the ability to proliferate and self-renew.Most current research on human brain tumors is focused on the molecular and cellular analysis of the bulk tumor mass. However, evidence in leukemia and more recently in solid tumors such as breast cancer suggests that the tumor cell population is heterogeneous with respect to proliferation and differentiation. Recently, several groups have described the existence of a cancer stem cell population in human brain tumors of different phenotypes from both children and adults. The finding of brain tumor stem cells (BTSCs) has been made by applying the principles for cell culture and analysis of normal neural stem cells (NSCs) to brain tumor cell populations and by identification of cell surface markers that allow for isolation of distinct tumor cell populations that can then be studied in vitro and in vivo. A population of brain tumor cells can be enriched for BTSCs by cell sorting of dissociated suspensions of tumor cells for the NSC marker CD133. These CD133+ cells, which also expressed the NSC marker nestin, represent a minority fraction of the entire brain tumor cell population, and exclusively generate clonal tumor spheres in suspension culture and exhibit increased self-renewal capacity. BTSCs can be induced to differentiate in vitro into tumor cells that phenotypically resembled the tumor from the patient. The identification of a BTSC provides a powerful tool to investigate the tumorigenic process in the central nervous system and to develop therapies targeted to the BTSC.In this investigation, to isolate and culture brain tumor stem cell (BTSC) from C6 glioma cell line (C6GCL) and to study their biological characteristics in vitro and in vivo, we can establish the methods of harvest and culture of BTSC and to observe the characteristics of proliferation and induce differentiation of BTSC. Then we construct the eukaryotic expression vector of TIMP-2 gene (pEGFPN1-TIMP-2) and to explore its expression in BTSC. After the pEGFPN1-TIMP-2 was transfected into cultured BTSC, we can examine its influence on BTSC in vivo. This was absolutely necessary to develop therapies targeted to the BTSC.