Biswas D K, Ahlers C M, Dezube B J, Pardee A B
Division of Cell Growth and Regulation, Dana-Farber Cancer Institute, Boston, Massachusetts 02115, USA.
Mol Med. 1994 Nov;1(1):31-43.
This investigation deals with the molecular mechanism of anti-human immunodeficiency virus type 1 (HIV-1) action of pentoxifylline (PTX) [1-(5'-oxohexyl)-3, 7-dimethylxanthine] a drug widely used for the treatment of conditions involving defective regional microcirculation.
The inhibition by PTX of protein kinase C (PKC) or cAMP-dependent protein kinase (PKA)-mediated activation by phorbol ester (PMA) and tumor necrosis factor alpha (TNF-alpha) of HIV-1-LTR-regulated reporter gene expression was studied in human CD4+ T lymphocytes (Jurkat) and human embryo kidney cells (293-27-2). A protein kinase C is involved in activation of NF-kappa B in whole cells, identified by using inhibitors specific for PKC- or PKA-catalyzed NF-kappa B activation in whole cell and cell-free systems.
PTX inhibited PKC- or PKA-catalyzed activation of NF-kappa B in cytoplasmic extracts from unstimulated Jurkat or 293-27-2 cells, but not interaction of preactivated NF-kappa B with its motifs. Calphostin C, a specific inhibitor of PKC, inhibited NF-kappa B activation and HIV-1 LTR-driven reporter gene expression in both PMA- and TNF-alpha-treated cells. In contrast, although H88 specifically inhibited PKA activity in the cell-free extract, it did not affect NF-kappa B action in PMA- or TNF-alpha-treated cells.
The mechanism of inhibitory action of PTX on virus replication and NF-kappa B-induced transactivation of HIV-1 gene expression has been elucidated as due to blocking PKC-dependent PMA- or TNF-alpha-induced activation of NF-kappa B in Jurkat and 293-27-2 cells. Other protein kinase inhibitors may be useful in down regulating transcription of HIV-1 provirus and thereby virus replication in HIV-infected patients.
本研究探讨己酮可可碱（PTX）[1-(5'-氧代己基)-3,7-二甲基黄嘌呤]抗人免疫缺陷病毒1型（HIV-1）作用的分子机制，PTX是一种广泛用于治疗局部微循环缺陷相关病症的药物。
在人CD4+ T淋巴细胞（Jurkat）和人胚肾细胞（293-27-2）中研究了PTX对蛋白激酶C（PKC）或环磷酸腺苷依赖性蛋白激酶（PKA）介导的佛波酯（PMA）和肿瘤坏死因子α（TNF-α）激活HIV-1长末端重复序列（LTR）调控的报告基因表达的抑制作用。通过在全细胞和无细胞系统中使用对PKC或PKA催化的NF-κB激活具有特异性的抑制剂，确定PKC参与全细胞中NF-κB的激活。
PTX抑制未刺激的Jurkat或293-27-2细胞胞质提取物中PKC或PKA催化的NF-κB激活，但不抑制预激活的NF-κB与其基序的相互作用。PKC的特异性抑制剂钙泊三醇C抑制PMA和TNF-α处理细胞中的NF-κB激活以及HIV-1 LTR驱动的报告基因表达。相比之下，尽管H88在无细胞提取物中特异性抑制PKA活性，但它不影响PMA或TNF-α处理细胞中的NF-κB作用。
已阐明PTX对病毒复制和NF-κB诱导的HIV-1基因表达反式激活的抑制作用机制是由于阻断Jurkat和293-27-2细胞中PKC依赖性PMA或TNF-α诱导的NF-κB激活。其他蛋白激酶抑制剂可能有助于下调HIV-1原病毒的转录，从而抑制HIV感染患者体内的病毒复制。
