The stimulation of metallothionein synthesis in neuroblastoma IMR-32 by zinc and cadmium but not dexamethasone.
The stimulation of metallothionein synthesis in neuroblastoma IMR-32 by zinc and cadmium but not dexamethasone.
复制标题
锌和镉刺激神经母细胞瘤 IMR-32 中金属硫蛋白的合成，但地塞米松不刺激。
DOI：
10.1007/bf02916611
复制
发表时间：
1989
影响因子：
3.9
通讯作者：
Timmins,P
中科院分区：
文献类型：
--
作者：
Ebadi,M;Takahashi,T;Timmins,P
金属硫蛋白是一类富含半胱氨酸和低分子量的金属结合蛋白，可被多种物质诱导，包括镉和锌等金属离子、糖皮质激素、干扰素和肿瘤促进剂。为了阐明最近发现的脑金属硫蛋白样蛋白的合成调控，以人常肝细胞为对照，比较了锌、镉和地塞米松对人神经母细胞瘤IMR-32细胞中金属硫蛋白的诱导作用。镉(1μM)和锌(100μM)均能显著促进神经母细胞瘤和常肝细胞金属硫蛋白对[35S]半胱氨酸的掺入。10μM的地塞米松可促进常细胞金属硫蛋白的合成，而2.5~100μM的地塞米松对神经母细胞瘤细胞金属硫蛋白的合成无明显影响。镉、锌对常细胞金属硫蛋白合成的刺激程度明显高于神经母细胞瘤细胞。神经母细胞瘤IMR-32对镉和锌的耐受性低于Chang细胞，这可能与这些离子在这些不同细胞中诱导金属硫蛋白的内在能力有关。这些研究的结果被解释为调控Chang和神经母细胞瘤细胞中金属硫蛋白合成的因素并不相同，这也表明肝脏和大脑中存在不同的调控机制。
Metallothioneins are a class of cysteine-rich and low molecular weight, metal-binding proteins that are inducible by a wide variety of agents, including metal ions, such as cadmium and zinc, glucocorticoid hormones, interferon, and tumor promoters. In an effort to delineate the regulation of the synthesis of the recently identified brain metallothionein-like protein, a study was undertaken to compare the induction of metallothionein in human neuroblastoma IMR-32 cells by zinc, cadmium, and dexamethasone using the human Chang liver cells as a control. Both cadmium (1 μM) and zinc (100 μM) significantly enhanced the incorporation of [35S]cysteine into metallothioneins isolated from both neuroblastoma and Chang liver cells. Dexamethasone in concentrations of 10 μMstimulated the synthesis of metallothionein in the Chang cells, whereas it had no effects on the synthesis of metallothionein in the neuroblastoma cells at concentrations ranging from 2.5–100 μM. The degree of stimulation of metallothionein synthesis in the Chang cells by cadmium and zinc was significantly higher than seen in neuroblastoma cells. The neuroblastoma IMR-32 exhibited less tolerance to the toxicity of both Cadmium and zinc than the Chang cells, which may correlate with the inherent ability of these ions to induce metallothioneins in these dissimilar cells. The results of these studies are interpreted to indicate that the factors regulating the synthesis of metallothioneins in the Chang and neuroblastoma cells are not identical, suggesting also of the presence of dissimilar regulatory mechanisms in the liver and brain.