Zhang Jia, Zhao Zhilong, Zu Chao, Hu Haijian, Shen Hui, Zhang Mingxin, Wang Jiansheng
Department of Surgical Oncology, First Affiliated Hospital of Medical School, Xi'an Jiaotong University, Xi'an, Shaanxi 710061, P.R. China.
Oncol Lett. 2013 Aug;6(2):407-414. doi: 10.3892/ol.2013.1425. Epub 2013 Jun 25.
Atrial natriuretic peptide (ANP) and brain NP (BNP) belong to the NP family that regulates mammalian blood volume and blood pressure. ANP signaling through NP receptor A (NPR-A)/cyclic guanosine 3'5'-monophosphate (cGMP)/ cGMP-dependent protein kinase (PKG) activates various downstream effectors involved in cell growth, apoptosis, proliferation and inflammation. Evidence has shown the critical role of plasma K channels in the regulation of tumor cell proliferation. However, the role of ANP in the proliferation of gastric cancer cells is not clear. In the present study, the expression of NPR-A in the human gastric cancer cell line, AGS, and the effect of ANP on the proliferation of AGS cells were investigated using western blotting, immunofluorescence, qPCR and patch clamp assays. The K current was also analyzed in the effect of ANP on the proliferation of AGS cells. NPR-A was expressed in the human gastric cancer AGS cell line. Lower concentrations of ANP promoted the proliferation of the AGS cells, although higher concentrations decreased their proliferation. Significant increases in the levels of cGMP activity were observed in the AGS cells treated with 10, 10 and 10 M ANP compared with the controls, but no significant differences were observed in the 10 and 10 M ANP groups. The patch clamp results showed that 10 M ANP significantly increased the tetraethylammonium (TEA)- and 293B-sensitive K current, while 10 M ANP significantly decreased the TEA- and 293B-sensitive K current. The results showed that 10 and 10 M ANP significantly upregulated the expression of potassium voltage-gated channel, KQT-like subfamily, member 1 (KCNQ1) at the protein and mRNA levels, although 10 and 10 M ANP significantly downregulated the expression of KCNQ1. The data indicated that lower and higher concentrations of ANP have opposite effects on the proliferation of AGS cells through cGMP-dependent or -independent pathways. KCNQ1 upregulation and downregulation by lower and higher concentrations of ANP, respectively, have separate effects on the promotion and inhibition of proliferation.
心房利钠肽（ANP）和脑钠肽（BNP）属于调节哺乳动物血容量和血压的钠肽家族。通过钠肽受体A（NPR-A）/环鸟苷3',5'-单磷酸（cGMP）/cGMP依赖性蛋白激酶（PKG）的ANP信号传导激活参与细胞生长、凋亡、增殖和炎症的各种下游效应器。有证据表明血浆钾通道在调节肿瘤细胞增殖中起关键作用。然而，ANP在胃癌细胞增殖中的作用尚不清楚。在本研究中，使用蛋白质印迹、免疫荧光、qPCR和膜片钳测定法研究了NPR-A在人胃癌细胞系AGS中的表达以及ANP对AGS细胞增殖的影响。还分析了K电流在ANP对AGS细胞增殖影响中的作用。NPR-A在人胃癌AGS细胞系中表达。较低浓度的ANP促进AGS细胞的增殖，尽管较高浓度会降低其增殖。与对照组相比，用10、10和10 μM ANP处理的AGS细胞中cGMP活性水平显著增加，但在10和10 μM ANP组中未观察到显著差异。膜片钳结果表明，10 μM ANP显著增加了四乙铵（TEA）和293B敏感的K电流，而10 μM ANP显著降低了TEA和293B敏感的K电流。结果表明，10和10 μM ANP在蛋白质和mRNA水平上显著上调钾电压门控通道、KQT样亚家族成员1（KCNQ1）的表达，尽管10和10 μM ANP显著下调KCNQ1的表达。数据表明，较低和较高浓度的ANP通过cGMP依赖性或非依赖性途径对AGS细胞的增殖具有相反的作用。较低和较高浓度的ANP分别对KCNQ1的上调和下调对增殖的促进和抑制具有单独的作用。
