Tavares-Valente Diana, Sousa Bárbara, Schmitt Fernando, Baltazar Fátima, Queirós Odília
Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho, 4710-057 Braga, Portugal.
PT Government Associate Laboratory, ICVS/3B's-Life and Health Sciences Research Institute/ Biomaterials, Biodegradables and Biomimetics, 4710-057 Braga/Guimarães, Portugal.
Pharmaceutics. 2021 Feb 9;13(2):242. doi: 10.3390/pharmaceutics13020242.
The reverse pH gradient is a major feature associated with cancer cell reprogrammed metabolism. This phenotype is supported by increased activity of pH regulators like ATPases, carbonic anhydrases (CAs), monocarboxylate transporters (MCTs) and sodium-proton exchangers (NHEs) that induce an acidic tumor microenvironment, responsible for the cancer acid-resistant phenotype. In this work, we analyzed the expression of these pH regulators and explored their inhibition in breast cancer cells as a strategy to enhance the sensitivity to chemotherapy. Expression of the different pH regulators was evaluated by immunofluorescence and Western blot in two breast cancer cell lines (MDA-MB-231 and MCF-7) and by immunohistochemistry in human breast cancer tissues. Cell viability, migration and invasion were evaluated upon exposure to the pH regulator inhibitors (PRIs) concanamycin-A, cariporide, acetazolamide and cyano-4-hydroxycinnamate. Additionally, PRIs were combined with doxorubicin to analyze the effect of cell pH dynamic disruption on doxorubicin sensitivity. Both cancer cell lines expressed all pH regulators, except for MCT1 and CAXII, only expressed in MCF-7 cells. There was higher plasma membrane expression of the pH regulators in human breast cancer tissues than in normal breast epithelium. Additionally, pH regulator expression was significantly associated with different molecular subtypes of breast cancer. pH regulator inhibition decreased cancer cell aggressiveness, with a higher effect in MDA-MB-231. A synergistic inhibitory effect was observed when PRIs were combined with doxorubicin in the breast cancer cell line viability. Our results support proton dynamic disruption as a breast cancer antitumor strategy and the use of PRIs to boost the activity of conventional therapy.
反向pH梯度是与癌细胞重编程代谢相关的一个主要特征。这种表型由诸如ATP酶、碳酸酐酶(CAs)、单羧酸转运体(MCTs)和钠-质子交换体(NHEs)等pH调节剂活性增加所支持,这些调节剂会诱导酸性肿瘤微环境,导致癌症的耐酸表型。在这项研究中,我们分析了这些pH调节剂的表达,并探索了在乳腺癌细胞中对它们的抑制作用,以此作为增强化疗敏感性的一种策略。通过免疫荧光和蛋白质印迹法在两种乳腺癌细胞系(MDA-MB-231和MCF-7)中评估了不同pH调节剂的表达,并通过免疫组织化学法在人乳腺癌组织中进行了评估。在暴露于pH调节剂抑制剂(PRIs) concanamycin-A、cariporide、乙酰唑胺和氰基-4-羟基肉桂酸酯后,评估了细胞活力、迁移和侵袭情况。此外,将PRIs与阿霉素联合使用,以分析细胞pH动态破坏对阿霉素敏感性的影响。两种癌细胞系均表达所有pH调节剂,但MCT1和CAXII除外,后者仅在MCF-7细胞中表达。人乳腺癌组织中pH调节剂的质膜表达高于正常乳腺上皮。此外,pH调节剂的表达与乳腺癌的不同分子亚型显著相关。pH调节剂抑制降低了癌细胞的侵袭性,对MDA-MB-231的影响更大。当PRIs与阿霉素联合用于乳腺癌细胞系活力时,观察到了协同抑制作用。我们的结果支持质子动态破坏作为一种乳腺癌抗肿瘤策略,以及使用PRIs来增强传统疗法的活性。