Brown Foundation Institute of Molecular Medicine for the Prevention of Human Diseases, The University of Texas Health Science Center at Houston, 1825 Pressler Street, Houston, TX 77030, USA.
Nitric Oxide. 2010 Jan 1;22(1):43-50. doi: 10.1016/j.niox.2009.11.007. Epub 2009 Dec 3.
Our previous studies demonstrate a differential expression of nitric oxide (NO) signaling components in ES cells and our recent study demonstrated an enhanced differentiation of ES cells into myocardial cells with NO donors and soluble guanylyl cyclase (sGC) activators. Since NO-cGMP pathway exhibits a diverse role in cancer, we were interested in evaluating the role of the NO-receptor sGC and other components of the pathway in regulation of the tumor cell proliferation. Our results demonstrate a differential expression of the sGC subunits, NOS-1 and PKG mRNA and protein levels in various human cancer models. In contrast to sGC alpha(1), robust levels of sGC beta(1) were observed in OVCAR-3 (ovarian) and MDA-MB-468 (breast) cancer cells which correlated well with the sGC activity and a marked increase in cGMP levels upon exposure to the combination of a NO donor and a sGC activator. NOC-18 (DETA NONOate; NO donor), BAY41-2272 (3-(4-amino-5-cyclopropylpyrimidin-2-yl)-1-(2-fluorobenzyl)-1H-pyrazolo[3,4-b]pyridine); sGC activator), NOC-18+BAY41-2272, IBMX (3-isobutyl-1-methylxanthine; phosphodiesterase inhibitor) and 8-bromo-cGMP (cGMP analog) caused growth inhibition and apoptosis in various cancer cell lines. To elucidate the molecular mechanisms involved in growth inhibition, we evaluated the effect of activators/inhibitors on ERK phosphorylation. Our studies indicate that BAY41-2272 or the combination NOC-18+BAY41-2272 caused inhibition of the basal ERK1/2 phosphorylation in OVCAR-3 (high sGC activity), SK-OV-3 and SK-Br-3 (low sGC activity) cell lines and in some cases the inhibition was rescued by the sGC inhibitor ODQ (1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one). These studies suggest that the effects of activators/inhibitors of NO-sGC-cGMP in tumor cell proliferation is mediated by both cGMP-dependent and independent mechanisms.
我们之前的研究表明，一氧化氮（NO）信号成分在胚胎干细胞中的表达存在差异，而我们最近的研究表明，NO 供体和可溶性鸟苷酸环化酶（sGC）激活剂可增强胚胎干细胞向心肌细胞的分化。由于 NO-cGMP 途径在癌症中表现出多种作用，我们有兴趣评估 NO 受体 sGC 和该途径的其他成分在调节肿瘤细胞增殖中的作用。我们的研究结果表明，在各种人类癌症模型中，sGC 亚基、NOS-1 和 PKG mRNA 和蛋白水平的表达存在差异。与 sGC alpha(1) 相反，在 OVCAR-3（卵巢）和 MDA-MB-468（乳腺）癌细胞中观察到稳健的 sGC beta(1) 水平，这与 sGC 活性以及暴露于 NO 供体和 sGC 激活剂组合时 cGMP 水平的显著增加很好地相关。NOC-18（DETA NONOate；NO 供体）、BAY41-2272（3-(4-氨基-5-环丙基嘧啶-2-基）-1-(2-氟苄基)-1H-吡唑并[3,4-b]吡啶）；sGC 激活剂）、NOC-18+BAY41-2272、IBMX（3-异丁基-1-甲基黄嘌呤；磷酸二酯酶抑制剂）和 8-溴-cGMP（cGMP 类似物）在各种癌细胞系中引起生长抑制和细胞凋亡。为了阐明参与生长抑制的分子机制，我们评估了激活剂/抑制剂对 ERK 磷酸化的影响。我们的研究表明，BAY41-2272 或 NOC-18+BAY41-2272 组合导致 OVCAR-3（高 sGC 活性）、SK-OV-3 和 SK-Br-3（低 sGC 活性）细胞系中基础 ERK1/2 磷酸化的抑制，并且在某些情况下，这种抑制可被 sGC 抑制剂 ODQ（1H-[1,2,4]噁二唑并[4,3-a]喹喔啉-1-酮）挽救。这些研究表明，NO-sGC-cGMP 激活剂/抑制剂在肿瘤细胞增殖中的作用是通过 cGMP 依赖性和非依赖性机制介导的。
