Growth-associated changes in glutathione content correlate with liver metastatic activity of B16 melanoma cells
Growth-associated changes in glutathione content correlate with liver metastatic activity of B16 melanoma cells
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DOI：
10.1023/a:1006725226078
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发表时间：
1999-01-01
影响因子：
4
通讯作者：
Estrela, JM
中科院分区：
文献类型：
--
作者：
Carretero, J;Obrador, E;Estrela, JM
以B16黑色素瘤(B16M)为模型，研究谷胱甘肽(GSH)代谢与肿瘤细胞转移活性的关系。B16M细胞体外指数生长初期GSH含量升高，12h达最大值37+/-3nmol/10(6)细胞，培养接近融合时逐渐下降至对照组(10+/-2nmol/10(6)细胞)。相反，随着B16M的生长，GSSG水平(0.5+/-0.2nmol/10(6)细胞)和谷胱甘肽外流速率(GSH+GSSG)(2.5+/-0.4nmol/10(6)细胞/h)保持不变。参与GSH合成或谷胱甘肽氧化还原循环的酶活性的变化不能解释谷胱甘肽状态(GSH/GSSG)的变化。然而，有两个事实有助于解释为什么B16M细胞内GSH水平发生变化：a)在低细胞密度培养的B16M细胞(LD细胞)中，高水平的GSH诱导其自身合成的反馈抑制；b)在高细胞密度培养物(HD细胞)中，胞囊(E)的转运受到细胞-细胞接触的限制，其有效性是GSH合成的主要限速步骤。脾内注射高GSH含量的B16M细胞(指数生长培养)显示出比低GSH含量的细胞(汇合细胞)更高的肝脏转移活性。然而，当低GSH含量的细胞(HD细胞)在GSH酯的存在下孵育时，GSH酯迅速进入细胞并提供游离GSH，其转移活性显著增加。我们的结果表明，GSH含量的变化调节了B16M细胞的转移行为。
B16 melanoma (B16M) was used to study the relationship between glutathione (GSH) metabolism and the metastatic acitivity of malignant cells. GSH content increased in B16M cells during the initial period of exponential growth in vitro, to reach a maximum of 37 +/- 3 nmol/10(6) cells 12 h after plating, and then gradually decreased to control values (10 +/- 2 nmol/10(6) cells) when cultures approached confluency. On the contrary, glutathione disulphide (GSSG) levels (0.5 +/- 0.2 nmol/10(6) cells) and the rate of glutathione efflux (GSH + GSSG) (2.5 +/- 0.4 nmol/10(6) cells per h) remained constant as B16M grew. Changes in enzyme activities involved in GSH synthesis or the glutathione redox cycle did not explain shifts in the glutathione status (GSH/GSSG). However, two facts contributed to explain why GSH levels changed within B16M cells: a) high intracellular levels of GSH induced a feed-back inhibition of its own synthesis in B16M cells from cultures with low cellular density (LD cells); b) transport of cyst(e)ine, whose availability is the major rate-limiting step for GSH synthesis, was limited by cell-cell contact in cultures with high cellular density (HD cells). Intrasplenic injection of B16M cells with high GSH content (exponentially-growing cultures) showed higher metastatic activity in the liver than cells with low GSH content (cells at confluency). However, when low GSH-content cells (HD cells) were incubated in the presence of GSH ester, which rapidly enters the cell and delivers free GSH, their metastatic activity significantly increased. Our results demonstrate that changes in GSH content regulate the metastatic behaviour of B16M cells.