摘要
背景与目的:长期以来,脑肿瘤等实体肿瘤中是否存在肿瘤干细胞一直存在争论,最近已经有报道从胶质瘤和髓母细胞瘤等脑肿瘤及其它系统实体肿瘤中成功分离出肿瘤干细胞。本研究旨在利用简化的无血清培养基和悬浮培养方法,从人髓母细胞瘤中分离培养脑肿瘤干细胞,观察其在体外的增殖、分化,鉴定其特异性标志物CD133和Nestin的表达,验证肿瘤组织切片中CD133阳性细胞的存在,为脑肿瘤干细胞的进一步研究打下基础。方法:术中取11例患者髓母细胞瘤组织,分离成单细胞悬液,接种于含表皮生长因子、成纤维生长因子以及B27添加剂的无血清培养基中悬浮培养,以分离其中的脑肿瘤干细胞;对其增殖形成的脑肿瘤干细胞球连续传代培养;并进行单克隆形成实验,以确定原代肿瘤组织中肿瘤干细胞的百分率,观察脑肿瘤干细胞球的形成过程。然后,将脑肿瘤干细胞球接种于含血清培养基,观察脑肿瘤干细胞的分化现象。最后,利用免疫荧光法检测脑肿瘤干细胞特异性标志物CD133和Nestin在脑肿瘤干细胞球中的表达;利用免疫组化法检测组织切片中CD133阳性细胞的分布,并计算CD133阳性细胞百分率。结果:本组11例髓母细胞瘤中均仅有少数肿瘤细胞能够在无血清培养基中存活并悬浮生长、增殖形成克隆性脑肿瘤干细胞球,传代后脑肿瘤干细胞仍保持很强的自我更新和增殖能力。单克隆形成实验表明原代肿瘤细胞中具有单克隆形成能力的肿瘤干细胞百分率为(31.18±6.18)%。在含血清培养基中脑肿瘤干细胞发生贴壁分化,产生具有多种细胞形态的分化细胞。脑肿瘤干细胞表达神经干细胞的特异性标志物CD133和Nestin;肿瘤组织切片中CD133阳性细胞呈巢状或散在分布,占全部肿瘤细胞的(33.06±8.57)%。结论:人髓母细胞瘤组织中存在一定量的具有自我更新和增殖能力、表达CD133和Nestin的脑肿瘤干细胞,并能在体外将其分离、培养和诱导分化。
BACKGROUND ＆ OBJECTIVE： Tumor stem cells have been isolated from several kinds of solid tumors, including primary brain tumors such as glioma and medulloblastoma. This investigation was to establish a simplified culture system to isolate and passage brain tumor stem cells （BTSCs） from human medulloblastoma, observe their proliferation and differentiation, and determine the expression of normal neural stem cell antigens, CD133 and Nestin, in BTSCs. METHODS： Eleven specimens of medulloblastoma were acutely dissociated and triturated into single cells without trypsin digestion. The tumor cells were seeded into serum-free DMEM/F12 medium （200 000 viable cells/ml） containing B27 （1：50）, basic fibroblast growth factor （bFGF, 20μg/L）, epidermal growth factor （EGF, 20μg /L）, insulin （4 u/L）, L-glutamine, and antibiotics. After generation, the primary brain tumor spheres （BTSs） were mechanically dissociated and passaged in the above serum-free medium. The monocIonal formation experiment was performed to determine the proportion of BTSCs in medulloblastoma and to observe the formation of BTSs. The differentiation of BTSCs was induced in mitogen-free DMEM/F12 medium supplemented with 10% fetal bovine serum. The expression of CD133 and Nestin in BTSs was observed with immunofluorescence staining; the distribution of CD133- positive cells in tumor sections was assessed by immunohistochemistry. RESULTS： In each of the 11 specimens, only a minority of medulloblastoma cells showed the capacity of self-renew and proliferation. These BTSCs generated free-floating neurosphere-like BTSs in the simplified serum-free medium. The proportion of BTSCs with monocIonal formation capacity in primary tumor cells was （31.18±6.18）%. The BTSCs attached to poly-L- lysine-coated coverslips and differentiated when the serum-supplemented medium was added. The expression of CD133 and Nestin was detected in BTSCs. CD133-positive cells scattered or formed nest-like aggregations in tumor masses, and accounted for （33.06 ±8.57）% of all tumor cells. CONCLUSIONS： BTSCs, with the capacity of self-renew and proliferation and express CD133 and Nestin, are exist in human medulloblastoma. They could be isolated and cultured in the simplified serum-free medium, and their differentiation could be induced in serum-supplemented medium.
出处
《癌症》
SCIE
CAS
CSCD
北大核心
2006年第2期241-246,共6页
Chinese Journal of Cancer
基金
湖南省自然科学基金项目(No.055JJ30060)
湖南省科技厅重点资助项目(No.02JTY2009)
湖南省卫生厅科研基金课题(No.B2003-016)~~
