Tsuruo Y, Ishimura K, Morita K
Department of Anatomy and Cell Biology, Tokushima University School of Medicine, Kuramoto, Tokushima, 770-8503, Japan.
Brain Res. 1998 Aug 10;801(1-2):130-6. doi: 10.1016/s0006-8993(98)00555-1.
Rat C6 glioma cells are considered to be well characterized, and therefore commonly used as a model system to investigate the function of glial cells. However, recent study has shown that an alteration in the expression of their phenotypic antigens is observed when the cells are maintained under the serum-free conditions, proposing the possibility that various properties of glioma cells can be altered by the growth conditions. To test this possibility, the effects of serum-free culture conditions on the expression of steroid 5alpha-reductase (5alpha-R) type 1 isozyme in glioma cells were examined using immunocytochemical technique. Immunoreactivity of 5alpha-R type 1 was confined to the perinuclear region of glioma cells cultured in serum-containing medium, and observed in the cytoplasmic space as well as the perinuclear region of the cells cultured in serum-free medium. In contrast, serum deprivation failed to affect the expression of phenotypic antigens, glial fibrillary acidic protein (GFAP) and 2',3'-cyclic nucleotide 3'-phosphodiesterase (CNPase). Further studies showed that the expression of cytoplasmic 5alpha-R immunoreactivity induced by serum deprivation was reversible, and might be attributed to removal of serum proteins rather than biologically active small molecules from culture medium. This alteration in the expression of 5alpha-R immunoreactivity is therefore considered to reflect the translocation of the enzyme from the perinuclear region to the cell cytoplasm rather than the induction of cytoplasmic enzyme, and suggest that the culture conditions cause an alteration in the subcellular localization of 5alpha-R type 1 isozyme without phenotypic change of the glioma cell.
大鼠C6胶质瘤细胞被认为具有良好的特征，因此通常用作研究胶质细胞功能的模型系统。然而，最近的研究表明，当细胞在无血清条件下培养时，其表型抗原的表达会发生改变，这表明胶质瘤细胞的各种特性可能会因生长条件而改变。为了验证这种可能性，我们使用免疫细胞化学技术研究了无血清培养条件对胶质瘤细胞中甾体5α-还原酶（5α-R）1型同工酶表达的影响。在含血清培养基中培养的胶质瘤细胞中，5α-R 1型的免疫反应性局限于核周区域，而在无血清培养基中培养的细胞的细胞质空间以及核周区域也观察到了这种反应性。相比之下，血清剥夺并未影响表型抗原胶质纤维酸性蛋白（GFAP）和2',3'-环核苷酸3'-磷酸二酯酶（CNPase）的表达。进一步的研究表明，血清剥夺诱导的细胞质5α-R免疫反应性的表达是可逆的，这可能归因于从培养基中去除血清蛋白而非生物活性小分子。因此，5α-R免疫反应性表达的这种改变被认为反映了该酶从核周区域向细胞质的转运，而不是细胞质酶的诱导，并表明培养条件导致了5α-R 1型同工酶亚细胞定位的改变，而胶质瘤细胞的表型没有变化。
