Watanabe K, Kazakova I, Furniss M, Miller S C
Signal Transduction Laboratory, Pharmaceutical Discovery Division, SRI International, Menlo Park, CA 94025, USA.
Cell Signal. 1999 May;11(5):371-83. doi: 10.1016/s0898-6568(99)00022-4.
In the human promonocytic U937 cell line, pyrrolidine dithiocarbamate (PDTC) was a potent inhibitor of the nuclear factor-kappaB (NF-kappaB) signalling pathway induced by the phorbol ester 12-O-tetradecanoylphorbol-13-acetate (TPA). However, PDTC did not inhibit tumour necrosis factor-alpha (TNF-alpha)-induced NF-kappaB DNA binding activity but potentiated the effect of TNF-alpha on kappaB-dependent gene expression. The stimulatory effect of PDTC with TNF-alpha was not observed with an HIV-1 LTR reporter construct containing two mutated kappaB binding sites or with a construct with a mutation of the activating protein (AP)-2 binding site located between the two kappaB elements. Two distinct signalling pathways, one mediated by TPA and the other by TNF-alpha, were shown to interact, functionally defining a threshold important in the inhibitory or stimulatory effect of PDTC on kappaB-dependent gene expression. Evidence that PDTC induced AP-1 DNA binding and AP-1 reporter gene activity, raised the hypothesis that the effect of PDTC was mediated by an interaction between the AP-1 pathway and p65(RelA). Co-transfection with expression vectors for p65(RelA) and the AP-1 subunits c-Fos and c-Jun resulted in a decrease in the stimulatory effect of PDTC on HIV-1 LTR activity. Co-transfection of p65(RelA) with Tam67, a dominant negative mutant of c-Jun defective in transactivation, stimulated the effect of PDTC on HIV-1 LTR activity. Evidence that the stimulatory effect of Tam67 with PDTC was reduced with c-Jun is consistent with the hypothesis.
在人原单核细胞U937细胞系中，吡咯烷二硫代氨基甲酸盐（PDTC）是佛波酯12 - O - 十四酰佛波醇 - 13 - 乙酸酯（TPA）诱导的核因子 - κB（NF - κB）信号通路的有效抑制剂。然而，PDTC并不抑制肿瘤坏死因子 - α（TNF - α）诱导的NF - κB DNA结合活性，反而增强了TNF - α对κB依赖性基因表达的作用。对于含有两个突变κB结合位点的HIV - 1 LTR报告基因构建体或两个κB元件之间的激活蛋白（AP） - 2结合位点发生突变的构建体，未观察到PDTC与TNF - α的刺激作用。结果表明，由TPA介导的和由TNF - α介导的两条不同信号通路相互作用，从功能上确定了一个阈值，该阈值对于PDTC对κB依赖性基因表达的抑制或刺激作用很重要。有证据表明PDTC诱导AP - 1 DNA结合和AP - 1报告基因活性，这提出了一个假设，即PDTC的作用是由AP - 1通路与p65（RelA）之间的相互作用介导的。用p65（RelA）以及AP - 1亚基c - Fos和c - Jun的表达载体共转染，导致PDTC对HIV - 1 LTR活性的刺激作用降低。p65（RelA）与Tam67（一种反式激活缺陷的c - Jun显性负突变体）共转染，刺激了PDTC对HIV - 1 LTR活性的作用。有证据表明，c - Jun会降低Tam67与PDTC的刺激作用，这与该假设一致。
J Transl Med. 2011-5-13
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