PIK3CA E542K 和 E545K 突变通过诱导宫颈癌中的β-连环蛋白/SIRT3 信号通路促进糖酵解和增殖。
The PIK3CA E542K and E545K mutations promote glycolysis and proliferation via induction of the β-catenin/SIRT3 signaling pathway in cervical cancer.
机构信息
Department of Gynecological Oncology, Fudan University Shanghai Cancer Center, Fudan University, Shanghai, 200032, China.
Department of Oncology, Shanghai Medical College, Fudan University, 270 Dong'an Road, Shanghai, 200032, China.
出版信息
J Hematol Oncol. 2018 Dec 14;11(1):139. doi: 10.1186/s13045-018-0674-5.
BACKGROUND
The study aims to present the effect of PIK3CA E542K and E545K mutations on glucose metabolism and proliferation and identify their underlying mechanisms in cervical cancer.
METHODS
The maximum standard uptake value (SUV) of tumors was detected byF-FDG PET/CT scan. In vitro, glycolysis analysis, extracellular acidification rate analysis, and ATP production were used to evaluate the impact of PIK3CA E542K and E545K mutations on glucose metabolism. The expression level of key glycolytic enzymes was evaluated by western blotting and immunohistochemical staining in cervical cancer cells and tumor tissues, respectively. Immunofluorescence analysis was used to observe the nuclear translocation of β-catenin. The target gene of β-catenin was analyzed by using luciferase reporter system. The glucose metabolic ability of the xenograft models was assessed by SUV from microPET/CT scanning.
RESULTS
Cervical cancer patients with mutant PIK3CA (E542K and E545K) exhibited a higher SUV value than those with wild-type PIK3CA (P = 0.037), which was confirmed in xenograft models. In vitro, enhanced glucose metabolism and proliferation was observed in SiHa and MS751 cells with mutant PIK3CA. The mRNA and protein expression of key glycolytic enzymes was increased. AKT/GSK3β/β-catenin signaling was highly activated in SiHa and MS751 cells with mutant PIK3CA. Knocking down β-catenin expression decreased glucose uptake and lactate production. In addition, the nuclear accumulation of β-catenin was found in SiHa cells and tumors with mutant PIK3CA. Furthermore, β-catenin downregulated the expression of SIRT3 via suppressing the activity of the SIRT3 promotor, and the reduced glucose uptake and lactate production due to the downregulation of β-catenin can be reversed by the transfection of SIRT3 siRNA in SiHa cells with mutant PIK3CA. The negative correlation between β-catenin and SIRT3 was further confirmed in cervical cancer tissues.
CONCLUSIONS
These findings provide evidence that the PI3K E542K and E545K/β-catenin/SIRT3 signaling axis regulates glucose metabolism and proliferation in cervical cancers with PIK3CA mutations, suggesting therapeutic targets in the treatment of cervical cancers.
TRIAL REGISTRATION
FUSCC 050432-4-1212B. Registered 24 December 2012 (retrospectively registered).
背景
本研究旨在探讨 PIK3CA E542K 和 E545K 突变对葡萄糖代谢和增殖的影响，并确定其在宫颈癌中的潜在机制。
方法
通过 F-FDG PET/CT 扫描检测肿瘤的最大标准摄取值（SUV）。在体外，通过糖酵解分析、细胞外酸化率分析和 ATP 产生来评估 PIK3CA E542K 和 E545K 突变对葡萄糖代谢的影响。通过蛋白质印迹和免疫组织化学染色分别评估宫颈癌细胞和肿瘤组织中关键糖酵解酶的表达水平。免疫荧光分析用于观察 β-连环蛋白的核转位。利用荧光素酶报告系统分析 β-连环蛋白的靶基因。通过 microPET/CT 扫描评估异种移植模型的葡萄糖代谢能力。
结果
与野生型 PIK3CA 相比，携带突变型 PIK3CA（E542K 和 E545K）的宫颈癌患者 SUV 值更高（P=0.037），这在异种移植模型中得到了证实。在体外，SiHa 和 MS751 细胞中存在突变型 PIK3CA 时，葡萄糖代谢和增殖增强。关键糖酵解酶的 mRNA 和蛋白表达增加。SiHa 和 MS751 细胞中存在突变型 PIK3CA 时，AKT/GSK3β/β-连环蛋白信号通路高度激活。下调 β-连环蛋白表达可减少葡萄糖摄取和乳酸生成。此外，在 SiHa 细胞和携带突变型 PIK3CA 的肿瘤中发现了 β-连环蛋白的核积累。此外，β-连环蛋白通过抑制 SIRT3 启动子的活性而下调 SIRT3 的表达，SiHa 细胞中突变型 PIK3CA 导致的葡萄糖摄取和乳酸生成减少可通过 SIRT3 siRNA 的转染逆转。在宫颈癌组织中进一步证实了 β-连环蛋白和 SIRT3 之间的负相关关系。
结论
这些发现为 PI3K E542K 和 E545K/β-连环蛋白/SIRT3 信号轴调节具有 PIK3CA 突变的宫颈癌中的葡萄糖代谢和增殖提供了证据，提示了治疗宫颈癌的治疗靶点。
试验注册
FUSCC 050432-4-1212B。2012 年 12 月 24 日注册（追溯注册）。
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