Department of Clinical Biochemistry, Cancer Research Laboratory, School of Medical Sciences, Tarbiat Modares University, Tehran, Iran.
Cell Biochem Funct. 2012 Apr;30(3):183-90. doi: 10.1002/cbf.1831. Epub 2011 Nov 18.
Activation of protein kinase G (PKG) by cyclic guanosine 3,5-monophosphate (cGMP) has become of considerable interest as a novel molecular approach for the induction of apoptosis in cancer cells. This study was conducted to investigate the role of PKG isoforms in the regulation of cell growth in human breast cancer cell lines MCF-7 and MDA-MB468. The expression levels of PKG isoforms were also examined using real-time reverse transcriptase polymerase chain reaction. No differences in the gene expression of PKG isoforms were observed between MCF-7 and MDA-MB-468 cells. To investigate the effects of PKG isoforms on the regulation of cell growth, the cGMP analogues 8-APT-cGMP (PKGIα activator), 8-Br-PET-cGMP (PKGIβ activator) and 8-pCPT-cGMP (PKGII activator) were employed. Apoptosis was assessed with the Annexin-V-propidium iodide (PI) staining, cell cycle analysis and caspase-3/9 activity assay. Treatment of MCF-7 and MDA-MB-468 cells with 8-Br-PET-cGMP resulted in a concentration-dependent cell growth inhibition and apoptosis, whereas neither PKGIα nor PKGII activators had any effect on the cell growth. The role of PKGIβ in the inhibition of cell growth was confirmed using PKGI and PKGII inhibitors. The present study is the first to demonstrate the involvement of PKGIβ in the inhibition of cell growth and induction of apoptosis in breast cancer cells.
蛋白激酶 G（PKG）的激活是通过环鸟苷酸 3'，5'-单磷酸（cGMP）实现的，这已成为诱导癌细胞凋亡的一种新的分子方法，引起了广泛关注。本研究旨在探讨 PKG 同工型在调节人乳腺癌 MCF-7 和 MDA-MB468 细胞系细胞生长中的作用。还使用实时逆转录聚合酶链反应检查了 PKG 同工型的表达水平。在 MCF-7 和 MDA-MB-468 细胞之间未观察到 PKG 同工型的基因表达差异。为了研究 PKG 同工型对细胞生长调节的影响，使用了 cGMP 类似物 8-APT-cGMP（PKGIα 激活剂）、8-Br-PET-cGMP（PKGIβ 激活剂）和 8-pCPT-cGMP（PKGII 激活剂）。通过 Annexin-V-碘化丙啶（PI）染色、细胞周期分析和 caspase-3/9 活性测定评估细胞凋亡。8-Br-PET-cGMP 处理 MCF-7 和 MDA-MB-468 细胞导致浓度依赖性细胞生长抑制和细胞凋亡，而 PKGIα 或 PKGII 激活剂对细胞生长没有任何影响。使用 PKGI 和 PKGII 抑制剂证实了 PKGIβ 在抑制细胞生长中的作用。本研究首次证明了 PKGIβ 参与了乳腺癌细胞的生长抑制和凋亡诱导。
