Tumor-secreted dickkopf2 accelerates aerobic glycolysis and promotes angiogenesis in clorectal cancer
Tumor-secreted dickkopf2 accelerates aerobic glycolysis and promotes angiogenesis in clorectal cancer
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肿瘤分泌的 dickkopf2 加速结直肠癌的有氧糖酵解并促进血管生成
DOI：
10.7150/thno.30056
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发表时间：
2019-01-01
期刊：
影响因子：
12.4
通讯作者：
Zhao, Liang
中科院分区：
文献类型：
--
作者：
Deng, Fengliu;Zhou, Rui;Zhao, Liang
血管生成是肿瘤进展和转移的一个基本过程。血管内皮生长因子（VEGF）家族及其受体被认为是血管生成最重要的调节因子。然而，抗vegf /VEGFR治疗的临床疗效并不理想，需要进一步了解肿瘤血管生成的机制。在这里，我们发现Dickkopf相关蛋白2 （DKK2）是一种在转移性结直肠癌组织中高度表达的分泌蛋白，可以通过经典的VEGF/VEGFR独立途径刺激血管生成。方法：从8对非转移性和转移性人结直肠癌（CRC）组织基因表达谱的微阵列数据中筛选出DKK2。采用免疫荧光组织化学染色（IHC）检测DKK2在结直肠癌组织中的表达及血管生成情况。采用鸡绒毛膜尿囊膜（CAM）法和人脐静脉内皮细胞（HUVEC）小管形成法分别进行体外和体内血管生成研究。采用酶联免疫吸附法（ELISA）测定培养基中乳酸和葡萄糖的浓度。荧光素酶报告基因检测用于验证miR-493-5p与DKK2的3'UTR之间的相互作用。结果：DKK2通过加速结直肠癌细胞的有氧糖酵解，使葡萄糖产生乳酸并在肿瘤微环境中积累，从而促进血管生成。乳酸作为DDK2的最终执行者刺激内皮细胞的管状形成，乳酸转运蛋白（MCT）抑制剂阻断乳酸分泌，在体内和体外都能显著中和结直肠癌的进展和转移。DKK2可与葡萄糖摄取所需的脂蛋白受体相关蛋白6协同，激活下游mTOR信号通路，加速乳酸分泌。此外，DKK2的表达通过miR-493-5p的去甲基化开启，这使得miR-493-5p与DKK2的3 ' - utr分离，并以自分泌或旁分泌的方式启动其对CRC进展的刺激作用。结论：DKK2通过一种新的不依赖vegf但与能量代谢相关的途径促进肿瘤转移和血管生成。DKK2可能是晚期结直肠癌患者临床治疗中一种潜在的抗血管生成靶点。
Angiogenesis is a fundamental process that involves in tumor progression and metastasis. Vascular endothelial growth factor (VEGF) family and their receptors are identified as the most prominent regulators of angiogenesis. However, the clinical efficacy of anti-VEGF/VEGFR therapy is not ideal, prompting the needs to further understand mechanisms behind tumor angiogenesis. Here, we found that Dickkopf associated protein 2 (DKK2), a secretory protein highly expressed in metastatic colorectal cancer tissues, could stimulate angiogenesis via a classic VEGF/VEGFR independent pathway. Methods: DKK2 was screened out from microarray data analyzing gene expression profiles of eight pairs of non-metastatic and metastatic human colorectal cancer (CRC) tissues. Immunofluorescence histochemical staining (IHC) was used to detect the expression of DKK2 and angiogenesis in CRC tissues. Chicken chorioallantoic membrane (CAM) assay and Human umbilical vein endothelial cells (HUVEC) tubule formation assay was used for in vitro and in vivo angiogenesis study, respectively. Lactate and glucose concentration in the culture medium was measured by enzyme-linked immunosorbent assay (ELISA). Luciferase reporter assay was used to verify the interaction between miR-493-5p and the 3'UTR of DKK2. Results: DKK2 could stimulate angiogenesis via accelerating the aerobic glycolysis of CRC cells, through which lactate is produced from glucose and accumulated in tumor microenvironment. Lactate functions as the final executor of DDK2 to stimulate tube formation of endothelial cells, and blockage of lactate secretion by lactate transporter (MCT) inhibitors dramatically neutralize the progression and metastasis of CRC both in vitro and in vivo. DKK2 could cooperate with lipoprotein receptor-related protein 6, which is required for glucose uptake, and activated the downstream mTOR signal pathway to accelerate lactate secretion. In addition, the expression of DKK2 is switched on via the demethylation of miR-493-5p, which allows the dissociated of miR-493-5p from the 3′-UTRs of DKK2 and initiates its stimulatory role on CRC progression in an autocrine or paracrine manner. Conclusion: DKK2 promotes tumor metastasis and angiogenesis through a novel VEGF-independent, but energy metabolism related pathway. DKK2 might be a potential anti-angiogenic target in clinical treatment for the advanced CRC patients.