Abdel-Mageed A B, Agrawal K C
Department of Pharmacology, Tulane Cancer Center, Tulane University School of Medicine, New Orleans, Louisiana 70112, USA.
Cancer Res. 1998 Jun 1;58(11):2335-8.
The antiapoptotic response and enhanced cellular proliferation observed in neoplastic cells on overexpression of metallothionein (MT) have been well documented. We have investigated the mechanisms associated with this phenomenon by using MT inducers that increased MT transcripts and stimulated growth in MCF-7 cells. A MT antisense phosphorothioate oligonucleotide inhibited growth induction by >50%, suggesting a potential role of MT in mediating the mitogenic effects of these agents. Mobility shift assays using oligonucleotides encompassing the consensus nuclear factor kappaB (NFkappaB) binding site and anti-MT antibody revealed activation and a specific interaction of NFkappaB with MT. Cotransfection experiments using expression and reporter constructs demonstrated that MT caused transactivation of NFkappaB. Gel shift assays using purified proteins showed a specific interaction between MT and the p50 subunit of NFkappaB. These data indicate that MT may be involved in the interaction of NFkappaB with the DNA-binding domain and further suggest a potential role for NFkappaB in mediating the antiapoptotic effects of MT.
金属硫蛋白（MT）过表达时肿瘤细胞中观察到的抗凋亡反应和增强的细胞增殖已得到充分证实。我们通过使用能增加MT转录本并刺激MCF-7细胞生长的MT诱导剂，研究了与该现象相关的机制。一种MT反义硫代磷酸酯寡核苷酸抑制生长诱导超过50%，表明MT在介导这些药物的促有丝分裂作用中具有潜在作用。使用包含共有核因子κB（NFκB）结合位点的寡核苷酸和抗MT抗体进行的凝胶迁移试验揭示了NFκB的激活以及与MT的特异性相互作用。使用表达和报告构建体的共转染实验表明MT导致NFκB的反式激活。使用纯化蛋白进行的凝胶迁移试验显示MT与NFκB的p50亚基之间存在特异性相互作用。这些数据表明MT可能参与NFκB与DNA结合结构域的相互作用，并进一步提示NFκB在介导MT的抗凋亡作用中具有潜在作用。
