Isolation and identification of cancer stem cells from central nervous system primitivetumors

Abstract

Objective To isolate and identify the cancer stem cells (CSCs) from central nervous system primitive neuroectodermal tumors (CNS-PNET). Methods Primary cultured tumor cells were derived from PNET/MB and sPNET specimens. The defined serum-free NSC medium was used to promote the formation of cells spheres to enrich CSCs subpopulation. CSCs were identified by second-ary sphere forming assay,fluorescent immunocytostaining and intracranial implantation in nude mice. Results Two types of CNS-PNET gave rise to clonal subsphere cells,some of which expressed neural stem cell markers including Sox2 and Nestin. Primary tumor cells could grow for 2 passages with the expression of Sox2 and Nestin. In the culture medium containing serum,sphere cells differentiated in-to multiple morphologic cell types with negative Sox2 and Nestin expression. All nude mice that im-planted with 105 CNS-PNET cells developed intracranial tumors,but none of the nude mice developed tumors when primary tumor cells were implanted. Conclusions Using defined serum-free NSC medi-um,CSCs with the ability to self-renew,initiate brain tumors upon implantation and multipotency can be isolated and enriched from CNS-PNET. Key words: Neuroectodermal tumors,primitive;  Tumor stem cells;  Cell separation