Nishizawa Y, Goto H G, Tanigaki Y, Fushiki S, Nishizawa Y
Department of Pathology, Osaka Medical Center for Cancer and Cardiovascular Diseases, Osaka 537-8511, Japan.
Anticancer Res. 2001 Mar-Apr;21(2A):1107-10.
SC-3 is a cloned cell line derived from an androgen-dependent mouse mammary tumor (Shionogi Carcinoma 115). A physiological level of androgen stimulates the growth of SC-3 cells through the production of androgen-induced growth factor. Methylcobalamin (MeCbl), one of the active cobalamins, inhibits the growth of SC-3 cells stimulated by androgen. It is known that apoptosis has an important role in tumor growth. The specific aim of this study is to examine the effects of MeCbl, in the presence of androgen, on apoptosis in SC-3 cells. Morphological analysis revealed budding nuclei and chromatin condensation in cells cultured with MeCbl, but few in cells cultured without MeCbl. Low molecular weight DNA extracted from cells cultured with or without MeCbl was analysed by gel electrophoresis. A characteristic nucleosomal size ladder was detected in the culture with MeCbl. The terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate-biotin nick end-labelling method was also used to evaluate apoptotic cell death in SC-3 cells. Apoptosis was observed more frequently in SC-3 cells treated with MeCbl than in those without MeCbl. These results demonstrate that androgen-dependent SC-3 cells undergo apoptosis by MeCbl even if in the presence of androgen.
SC - 3是一种从雄激素依赖性小鼠乳腺肿瘤（狮王癌115）衍生而来的克隆细胞系。生理水平的雄激素通过产生雄激素诱导生长因子来刺激SC - 3细胞的生长。甲钴胺（MeCbl）是活性钴胺素之一，可抑制雄激素刺激的SC - 3细胞的生长。众所周知，细胞凋亡在肿瘤生长中起重要作用。本研究的具体目的是研究在雄激素存在的情况下，MeCbl对SC - 3细胞凋亡的影响。形态学分析显示，用MeCbl培养的细胞中出现核出芽和染色质浓缩，但未用MeCbl培养的细胞中很少出现。对用或未用MeCbl培养的细胞提取的低分子量DNA进行凝胶电泳分析。在用MeCbl培养的细胞中检测到特征性的核小体大小梯度。末端脱氧核苷酸转移酶介导的脱氧尿苷三磷酸生物素缺口末端标记法也用于评估SC - 3细胞中的凋亡性细胞死亡。与未用MeCbl处理的SC - 3细胞相比，用MeCbl处理的SC - 3细胞中更频繁地观察到细胞凋亡。这些结果表明，即使在雄激素存在的情况下，雄激素依赖性SC - 3细胞也会因MeCbl而发生凋亡。
