INSERM, SAINBIOSE U1059 Team DVH, Universite de Lyon, UJM-Saint-Etienne, F-42023, SAINT-ETIENNE, France.
Universite de Lyon, UJM-Saint-Etienne, SNA-EPIS, EA4607, F-42023, SAINT-ETIENNE, France.
Curr Mol Pharmacol. 2018;11(2):133-139. doi: 10.2174/1874467208666161128152518.
The high degree of malignancy of tumour cells is linked to alterations of many physiological parameters like the intracellular pH (pHi). The pHi in cancer cell line is regulated by the carbonic anhydrase IX (CA IX). The main enzymatic function of the CA IX protein is to catalyze the hydration of carbon dioxide into bicarbonate ions and protons. CA IX expression in a broad variety of human tumor tissues is associated with resistance to therapy. One promising approach is to target the mechanism regulating pH homeostasis with carbonic anhydrase inhibitors like sulfamides and coumarins families.
In this work we have evaluated effects of umbelliferone and acetazolamide in a high resistant melanoma cell line (A375) over expressing CA IX. Impact of effective doses of CA IX inhibitors on apoptosis, intracellular pH (pHi), CA IX protein expression and functionality have been investigated. Determination of effective doses of CA IX inhibitors was performed with MTT tests. We also evaluated sensitization effect of CA inhibitors to conventional therapy as dacarbazin.
We have used 10 µM Umbelliferone and 100 µM Acetazolamide as effective doses for 24h. These doses did not induce any apoptosis. Umbelliferone induced a more important pHi decrease than Acetalozamide from 7.3 to 7.08 and to 7.12 respectively, and a more important decrease in s-CA IX fraction showing a decrease in CA IX function. We have demonstrated that pre-treatment with umbelliferone or acetazolamide allows a better dacarbazin efficacy.
We have demonstrated that inhibitors modify intracellular pH and CAIX functionality and sensitize cells to Dacarbazin. These original results complete the knowledge on Sulfamide CA IX inhibitors, bring new insights about Coumarin compounds and offer new possibilities in high grade melanoma therapies.
肿瘤细胞的高恶性程度与许多生理参数的改变有关，如细胞内 pH 值（pHi）。癌细胞系的 pHi 由碳酸酐酶 IX（CA IX）调节。CA IX 蛋白的主要酶功能是催化二氧化碳水合生成碳酸氢根离子和质子。CA IX 在广泛的人类肿瘤组织中的表达与治疗抵抗有关。一种有前途的方法是用碳酸酐酶抑制剂（如磺胺类和香豆素类家族）靶向调节 pH 平衡的机制。
在这项工作中，我们评估了伞形酮和乙酰唑胺在高耐药黑色素瘤细胞系（A375）中对 CA IX 过表达的影响。研究了 CA IX 抑制剂的有效剂量对细胞凋亡、细胞内 pH 值（pHi）、CA IX 蛋白表达和功能的影响。用 MTT 试验测定 CA IX 抑制剂的有效剂量。我们还评估了 CA 抑制剂对常规治疗如达卡巴嗪的增敏作用。
我们使用 10 µM 伞形酮和 100 µM 乙酰唑胺作为 24 小时的有效剂量。这些剂量不会诱导任何凋亡。伞形酮诱导的 pHi 下降比乙酰唑胺更显著，从 7.3 下降到 7.08 和 7.12，并且 s-CA IX 分数下降更显著，表明 CA IX 功能下降。我们证明，用伞形酮或乙酰唑胺预处理可以提高达卡巴嗪的疗效。
我们证明了抑制剂可以改变细胞内 pH 值和 CAIX 功能，并使细胞对达卡巴嗪敏感。这些原始结果补充了磺胺类 CA IX 抑制剂的知识，为香豆素类化合物提供了新的见解，并为高级黑色素瘤治疗提供了新的可能性。
