Carbonic anhydrase 2 (CAII) supports tumor blood endothelial cell survival under lactic acidosis in the tumor microenvironment
Carbonic anhydrase 2 (CAII) supports tumor blood endothelial cell survival under lactic acidosis in the tumor microenvironment
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DOI：
10.1186/s12964-019-0478-4
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发表时间：
2019-12-17
影响因子：
8.4
通讯作者：
Hida, Kyoko
中科院分区：
文献类型：
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作者：
Annan, Dorcas A.;Maishi, Nako;Hida, Kyoko
背景肿瘤内皮细胞(TECs)执行肿瘤血管生成，这是肿瘤生长和转移所必需的。肿瘤细胞通过糖酵解产生大量乳酸；然而，TECs在高乳酸条件下存活并使肿瘤血管生成的机制仍不清楚。方法采用毛细管电泳联用飞行时间质谱仪分析血管内皮细胞和正常内皮细胞的代谢产物。用定量逆转录-聚合酶链式反应检测pH调节因子在TECs和NECs中的表达。用四甲基偶氮唑蓝比色法检测细胞增殖。Western blotting和ELISA法分别检测细胞内单羧酸转运体1和碳酸氢酶2(CAII)蛋白的表达。建立人肿瘤移植瘤模型，观察CA抑制对肿瘤血管生成的影响。免疫组织化学染色观察CAII表达、肿瘤微血管密度、微血管周细胞覆盖率和缺氧情况。结果与NECs不同的是，TECs在乳酸介质中增殖。TECS在体外和体内均可上调CAII的表达。在乳酸酸中毒和营养充足的条件下，CAII基因敲除降低了TEC的存活率。血管内皮生长因子A和血管内皮生长因子受体信号转导诱导神经内皮细胞表达CAII。乙酰唑胺抑制CAII可最小限度地减少体内肿瘤血管生成。然而，在乙酰唑胺治疗后，成熟血管数量增加，与贝伐单抗治疗相似。此外，服用乙酰唑胺的小鼠肺转移减少。结论CAII等pH调节剂对血管成熟度有影响，是抗血管生成治疗的有效靶点。
Background Tumor endothelial cells (TECs) perform tumor angiogenesis, which is essential for tumor growth and metastasis. Tumor cells produce large amounts of lactic acid from glycolysis; however, the mechanism underlying the survival of TECs to enable tumor angiogenesis under high lactic acid conditions in tumors remains poorly understood. Methodology The metabolomes of TECs and normal endothelial cells (NECs) were analyzed by capillary electrophoresis time-of-flight mass spectrometry. The expressions of pH regulators in TECs and NECs were determined by quantitative reverse transcription-PCR. Cell proliferation was measured by the MTS assay. Western blotting and ELISA were used to validate monocarboxylate transporter 1 and carbonic anhydrase 2 (CAII) protein expression within the cells, respectively. Human tumor xenograft models were used to access the effect of CA inhibition on tumor angiogenesis. Immunohistochemical staining was used to observe CAII expression, quantify tumor microvasculature, microvessel pericyte coverage, and hypoxia. Results The present study shows that, unlike NECs, TECs proliferate in lactic acidic. TECs showed an upregulated CAII expression both in vitro and in vivo. CAII knockdown decreased TEC survival under lactic acidosis and nutrient-replete conditions. Vascular endothelial growth factor A and vascular endothelial growth factor receptor signaling induced CAII expression in NECs. CAII inhibition with acetazolamide minimally reduced tumor angiogenesis in vivo. However, matured blood vessel number increased after acetazolamide treatment, similar to bevacizumab treatment. Additionally, acetazolamide-treated mice showed decreased lung metastasis. Conclusion These findings suggest that due to their effect on blood vessel maturity, pH regulators like CAII are promising targets of antiangiogenic therapy.