Abstract：
BACKGROUND: Cyclic guanosine monophosphate (cGMP)-dependent protein kinase I (PKG-I), a serine/threonine kinase, is important in tumor development. The present study determines that the cGMP/PKG I pathway is essential for promoting cell proliferation and survival in human ovarian cancer cells, whereas cGMP analog has been shown to lead to growth inhibition and apoptosis of various cancer cells. The role of cGMP/PKG I pathway in epithelial ovarian cancer (EOC), therefore, remains controversial. We investigated the effect of cGMP/PKG I pathway and the underlying mechanism in EOC.
RESULTS: The results showed that exogenous 8-Bromoguanosine-3\', 5\'-cyclic monophosphate (8-Br-cGMP) (cGMP analog) could antagonize the effects by EGF, including suppressing proliferation, invasion and migration of EOC cells. In vivo, 8-Br-cGMP hampered the growth of the xenograft tumor. Additionally, the expressions of epidermal growth factor receptor (EGFR), matrix metallopeptidase 9 (MMP9), proliferating cell nuclear antigen and Ki67 in xenograft tumor were decreased after 8-Br-cGMP intervention. Further research demonstrated that 8-Br-cGMP decreased the phosphorylation of EGFR (Y992) and downstream proteins phospholipase Cγ1 (PLC γ1) (Y783), calmodulin kinase II (T286) and inhibited cytoplasmic Ca2+ release as well as PKC transferring to cell membrane. It\'s worth noting that the inhibition was 8-Br-cGMP dose-dependent and 8-Br-cGMP showed similar inhibitory effect on EOC cells compared with U-73122, a specific inhibitor of PLC γ1.
CONCLUSIONS: The activation of endogenous PKG I by addition of exogenous 8-Br-cGMP could inhibit EOC development probably via EGFR/PLCγ1 signaling pathway. 8-Br-cGMP/PKG I provide a new insight and strategy for EOC treatment.
RESULTS: The results showed that exogenous 8-Bromoguanosine-3\', 5\'-cyclic monophosphate (8-Br-cGMP) (cGMP analog) could antagonize the effects by EGF, including suppressing proliferation, invasion and migration of EOC cells. In vivo, 8-Br-cGMP hampered the growth of the xenograft tumor. Additionally, the expressions of epidermal growth factor receptor (EGFR), matrix metallopeptidase 9 (MMP9), proliferating cell nuclear antigen and Ki67 in xenograft tumor were decreased after 8-Br-cGMP intervention. Further research demonstrated that 8-Br-cGMP decreased the phosphorylation of EGFR (Y992) and downstream proteins phospholipase Cγ1 (PLC γ1) (Y783), calmodulin kinase II (T286) and inhibited cytoplasmic Ca2+ release as well as PKC transferring to cell membrane. It\'s worth noting that the inhibition was 8-Br-cGMP dose-dependent and 8-Br-cGMP showed similar inhibitory effect on EOC cells compared with U-73122, a specific inhibitor of PLC γ1.
CONCLUSIONS: The activation of endogenous PKG I by addition of exogenous 8-Br-cGMP could inhibit EOC development probably via EGFR/PLCγ1 signaling pathway. 8-Br-cGMP/PKG I provide a new insight and strategy for EOC treatment.
摘要：
背景：环磷酸鸟苷（cGMP）依赖性蛋白激酶I（PKG-I），丝氨酸/苏氨酸激酶，在肿瘤的发展中很重要。本研究确定cGMP/PKGI通路对于促进人卵巢癌细胞的增殖和存活至关重要。而cGMP类似物已被证明可导致各种癌细胞的生长抑制和凋亡。cGMP/PKGI通路在上皮性卵巢癌(EOC)中的作用,因此,仍然有争议。我们研究了cGMP/PKGI通路在EOC中的作用及其潜在机制。
结果：结果表明，外源8-溴鸟苷-3'，5'-环单磷酸酯（8-Br-cGMP）（cGMP类似物）可以拮抗EGF的作用，包括抑制增殖，EOC细胞的侵袭和迁移。在体内,8-Br-cGMP阻碍了异种移植肿瘤的生长。此外,表皮生长因子受体（EGFR）的表达，基质金属肽酶9（MMP9），8-Br-cGMP干预后，异种移植瘤的增殖细胞核抗原和Ki67降低。进一步研究表明，8-Br-cGMP降低了EGFR（Y992）和下游蛋白磷脂酶Cγ1（PLCγ1）（Y783）的磷酸化，钙调蛋白激酶II（T286）并抑制细胞质Ca2释放以及PKC向细胞膜的转移。值得注意的是，这种抑制作用是8-Br-cGMP剂量依赖性的，与PLCγ1的特异性抑制剂U-73122相比，8-Br-cGMP对EOC细胞具有相似的抑制作用。
结论：通过添加外源性8-Br-cGMP激活内源性PKGI可能通过EGFR/PLCγ1信号通路抑制EOC的发展。8-Br-cGMP/PKGI为EOC治疗提供了新的思路和策略。
结果：结果表明，外源8-溴鸟苷-3'，5'-环单磷酸酯（8-Br-cGMP）（cGMP类似物）可以拮抗EGF的作用，包括抑制增殖，EOC细胞的侵袭和迁移。在体内,8-Br-cGMP阻碍了异种移植肿瘤的生长。此外,表皮生长因子受体（EGFR）的表达，基质金属肽酶9（MMP9），8-Br-cGMP干预后，异种移植瘤的增殖细胞核抗原和Ki67降低。进一步研究表明，8-Br-cGMP降低了EGFR（Y992）和下游蛋白磷脂酶Cγ1（PLCγ1）（Y783）的磷酸化，钙调蛋白激酶II（T286）并抑制细胞质Ca2释放以及PKC向细胞膜的转移。值得注意的是，这种抑制作用是8-Br-cGMP剂量依赖性的，与PLCγ1的特异性抑制剂U-73122相比，8-Br-cGMP对EOC细胞具有相似的抑制作用。
结论：通过添加外源性8-Br-cGMP激活内源性PKGI可能通过EGFR/PLCγ1信号通路抑制EOC的发展。8-Br-cGMP/PKGI为EOC治疗提供了新的思路和策略。
