Antonysamy M A, Moticka E J, Ramkumar V
Department of Pharmacology, Southern Illinois University School of Medicine, Springfield 62794, USA.
J Immunol. 1995 Sep 15;155(6):2813-21.
CTLL-2 cells are a clone of CTL that are dependent on IL-2 for proliferation. In addition to various cytokine receptors, we observed that these cells express three subtypes of adenosine receptors (ARs). In an initial attempt to delineate the functions of these receptors in CTLL-2 cells, we tested their role in proliferation. Elimination of endogenous adenosine with adenosine deaminase (ADA) markedly suppressed IL-2-dependent proliferation of these cells. This proliferative response was restored by addition of R-phenylisopropyladenosine (R-PIA), a non-hydrolyzable adenosine analogue. The stimulatory response to R-PIA was attenuated following blockade of ARs by 0.5 mM theophylline and 10 microM BW-A1433, but not by blockade of the A1AR with 100 nM xanthine amine congener. The rank order of potency of adenosine analogues in proliferation assays was R-PIA > or = N-ethylcarboxamide adenosine > S-PIA > PAPA-APEC (a substituted ethylamino-5'-N-ethylcarboxamidoadenosine). These data suggest a potential role of the A3AR in the proliferative response. R-PIA stimulates production of 1,4,5-inositol trisphosphate in CTLL-2 cells, suggesting a role of the phospholipase C signaling pathway in the proliferative response. A23187 (100 nM) and phorbol 12,13 dibutyrate (10 nM), but not 4 alpha-phorbol (10 nM), were able to restore IL-2-dependent CTLL-2 proliferation in the presence of ADA. Furthermore, inhibition of protein kinase C by staurosporine (10 nM) and of phospholipase C by tricyclodecan-9-yl-xanthogenate (D609) blocked R-PIA-mediated cell proliferation. These data demonstrate an obligatory role of adenosine in IL-2-dependent proliferation of CTLL-2 cells and support the involvement of an AR-stimulated phospholipase C signaling pathway in this process.
CTLL-2细胞是一种依赖白细胞介素-2进行增殖的细胞毒性T淋巴细胞克隆。除了各种细胞因子受体外，我们观察到这些细胞表达三种亚型的腺苷受体（ARs）。在初步尝试描绘这些受体在CTLL-2细胞中的功能时，我们测试了它们在增殖中的作用。用腺苷脱氨酶（ADA）消除内源性腺苷可显著抑制这些细胞依赖白细胞介素-2的增殖。通过添加R-苯异丙基腺苷（R-PIA），一种不可水解的腺苷类似物，这种增殖反应得以恢复。在用0.5 mM茶碱和10 microM BW-A1433阻断ARs后，对R-PIA的刺激反应减弱，但用100 nM黄嘌呤胺类似物阻断A1AR则没有这种效果。腺苷类似物在增殖试验中的效力顺序为R-PIA≥N-乙基甲酰胺腺苷＞S-PIA＞PAPA-APEC（一种取代的乙氨基-5'-N-乙基甲酰胺腺苷）。这些数据表明A3AR在增殖反应中可能发挥作用。R-PIA刺激CTLL-2细胞中1,4,5-肌醇三磷酸的产生，表明磷脂酶C信号通路在增殖反应中发挥作用。在ADA存在的情况下，A23187（100 nM）和佛波醇12,13-二丁酸酯（10 nM），但不是4α-佛波醇（10 nM），能够恢复依赖白细胞介素-2的CTLL-2增殖。此外，星形孢菌素（10 nM）对蛋白激酶C的抑制以及三环癸烷-9-基-黄原酸酯（D609）对磷脂酶C的抑制阻断了R-PIA介导的细胞增殖。这些数据证明了腺苷在CTLL-2细胞依赖白细胞介素-2的增殖中的必要作用，并支持AR刺激的磷脂酶C信号通路参与这一过程。
