碳酸酐酶催化CO2/HCO3-缓冲反应，对有效H+流动、pH动力学和细胞酸碱感知具有重要意义。然而，碳酸酐酶对癌症和基质细胞功能、它们之间的相互作用以及患者预后的综合影响尚不清楚。我们将（a）人类蛋白质组学数据以及临床病理和预后信息相结合的单细胞和大块转录组数据进行生物信息学分析；（b）基于定量反转录和聚合酶链反应的乳腺组织基因表达的体外实验研究，基于荧光共聚焦显微镜的胞内和胞外pH记录，以及人类和小鼠乳腺癌活检标本中的免疫组织化学蛋白鉴定；以及（c）基于实验性诱导的小鼠乳腺癌进行体内肿瘤大小测量、pH敏感型微电极记录和微透析代谢物分析。特别是细胞外同工酶CA4、CA6、CA9、CA12和CA14在人类和小鼠乳腺癌发生过程中发生了强烈的表达变化。在具有基底样/三阴性乳腺癌的患者中，细胞外碳酸酐酶的高表达负向预测生存，然而令人惊讶的是，细胞外碳酸酐酶在HER2/ErbB2丰富乳腺癌患者中呈正性预测患者生存。碳酸酐酶抑制剂可以减弱人类和小鼠乳腺癌组织中细胞净酸排出和细胞外H+消除的能力。在体内给予碳酸酐酶抑制剂乙酰唑胺可以使ErbB2诱导的小鼠乳腺癌微环境酸化，限制肿瘤免疫浸润（CD3+T细胞、CD19+B细胞、F4/80+巨噬细胞），降低炎症因子（Il1a、Il1b、Il6）和转录因子（Nfkb1）的表达，并加速肿瘤生长。支持碳酸酐酶的免疫调节作用，与HER2丰富乳腺癌中高细胞外碳酸酐酶表达相关的患者生存益处取决于肿瘤炎症特征。乙酰唑胺可以降低乳腺组织和血液中的乳酸水平，而不影响乳腺肿瘤灌注，这表明碳酸酐酶抑制可以降低发酵性糖酵解。因此我们得出结论，碳酸酐酶（a）通过加速癌细胞和间质空间中的H+消除来提高乳腺癌的pH值，（b）在ErbB2/HER2驱动的乳腺癌中提高免疫浸润和炎症，限制肿瘤生长并改善患者预后。

Carbonic anhydrases catalyze CO2/HCO3- buffer reactions with implications for effective H+ mobility, pH dynamics, and cellular acid-base sensing. Yet, the integrated consequences of carbonic anhydrases for cancer and stromal cell functions, their interactions, and patient prognosis are not yet clear.We combine (a) bioinformatic analyses of human proteomic data and bulk and single-cell transcriptomic data coupled to clinicopathologic and prognostic information; (b) ex vivo experimental studies of gene expression in breast tissue based on quantitative reverse transcription and polymerase chain reactions, intracellular and extracellular pH recordings based on fluorescence confocal microscopy, and immunohistochemical protein identification in human and murine breast cancer biopsies; and (c) in vivo tumor size measurements, pH-sensitive microelectrode recordings, and microdialysis-based metabolite analyses in mice with experimentally induced breast carcinomas.Carbonic anhydrases-particularly the extracellular isoforms CA4, CA6, CA9, CA12, and CA14-undergo potent expression changes during human and murine breast carcinogenesis. In patients with basal-like/triple-negative breast cancer, elevated expression of the extracellular carbonic anhydrases negatively predicts survival, whereas, surprisingly, the extracellular carbonic anhydrases positively predict patient survival in HER2/ErbB2-enriched breast cancer. Carbonic anhydrase inhibition attenuates cellular net acid extrusion and extracellular H+ elimination from diffusion-restricted to peripheral and well-perfused regions of human and murine breast cancer tissue. Supplied in vivo, the carbonic anhydrase inhibitor acetazolamide acidifies the microenvironment of ErbB2-induced murine breast carcinomas, limits tumor immune infiltration (CD3+ T cells, CD19+ B cells, F4/80+ macrophages), lowers inflammatory cytokine (Il1a, Il1b, Il6) and transcription factor (Nfkb1) expression, and accelerates tumor growth. Supporting the immunomodulatory influences of carbonic anhydrases, patient survival benefits associated with high extracellular carbonic anhydrase expression in HER2-enriched breast carcinomas depend on the tumor inflammatory profile. Acetazolamide lowers lactate levels in breast tissue and blood without influencing breast tumor perfusion, suggesting that carbonic anhydrase inhibition lowers fermentative glycolysis.We conclude that carbonic anhydrases (a) elevate pH in breast carcinomas by accelerating net H+ elimination from cancer cells and across the interstitial space and (b) raise immune infiltration and inflammation in ErbB2/HER2-driven breast carcinomas, restricting tumor growth and improving patient survival.© 2023. The Author(s).