Cellular and radiobiological effects of carbonic anhydrase IX in human breast cancer cells

Abstract

Hypoxia-induced carbonic anhydrase IX (CAIX) is involved in intracellular and extracellular pH regulation, which is critical for tumor growth and metastasis. CAIX is overexpressed in breast cancer and is associated with the poor survival of patients after radiotherapy. Therefore, we evaluated the cellular and radiobiological effects of CAIX inhibition in human breast cancer cells. We used CA9 siRNA and the CA inhibitor (CAI) U104, respectively, to inhibit CAIX expression and activity in basal triple-negative MDA-MB-231 and luminal MCF-7 cells under hypoxic conditions. We investigated the effects of CAIX inhibition on CA9 mRNA and CAIX protein level, as well as on CAIX activity, intracellular pH, proliferation, apoptosis, clonogenic survival, migration, cell cycle distribution and radiosensitivity. CA9 siRNA and CAI U104 decreased CA9 mRNA and CAIX protein level in MDA-MB-231 and MCF-7 cells. Furthermore, incubation with CAI U104 significantly decreased carbonic anhydrase activity and reduced the intracellular pH. Additionally, CA9 siRNA or U104 reduced clonogenic survival, migration and the number of cells in the G 0 /G 1 phase, induced apoptosis and demonstrated additive or synergistic effects in combination with irradiation. In conclusion, combination of CAIX inhibition and irradiation is a promising treatment strategy against breast cancer with hypoxia-induced CAIX expression.

Carbonic Anhydrase Inhibitors Targeting Metabolism and Tumor Microenvironment

“…Other groups also used SLC-0111 in various biomedical studies in which selective inhibition of some CA isoforms was needed. These include the effects on prostate cancer cells of SLC-0111 alone or in combination with daunorubicin [ 184 ], radiobiological effects of CA IX inhibition in human breast cancer cells [ 185 ], microvascular endothelial cell pH regulation [ 186 ], glycolysis and migration suppression in pulmonary microvascular endothelial cells [ 187 ], and the involvement of CA isoforms in mitochondrial biogenesis and in the control of lactate production in human Sertoli cells [ 188 ]. All these studies confirm the usefulness of this clinical candidate in tumors and other biomedical conditions.…”

Preclinical Evaluation of Ureidosulfamate Carbonic Anhydrase IX/XII Inhibitors in the Treatment of Cancers

“…Ureido-substituted benzenesulfonamide Compound 25 (4-([(3’-nitrophenyl)carbamoyl]amino) benzenesulfonamide) showed a strong anti-metastatic effect in the 4T1 (murine breast carcinoma) intravenous model [31]. Treating MDA-MB-231 and MCF-7 cells with U-104 led to a significant reduction in CAIX expression and activity, coinciding with a reduction in clonogenic survival, migration and cells in G0/G1 phase, and an increase in the level of apoptotic cells [32]. U-104 (SLC-0111) (4-[[[(4-fluorophenyl)amino]carbonyl]amino]-benzenesulfonamide) significantly inhibited primary tumour growth in the orthotopic MDA-MB-231 model and inhibited metastases formation in the 4T1 experimental metastasis model [33].…”

“…In combination with chemotherapy drug paclitaxel, U-104 was able to target the Paclitaxel-resistant cells, reducing the primary tumour growth and metastasis formation. U-104 sensitised MDA-MB-231 and MCF-7 breast cancer cells to irradiation [32]. Carbohydrate-based sulfamates CAXII inhibitors (here compounds 1, 2 and 4) are highly effective in human cancer cell lines expressing different levels of CAXII and P-glycoprotein (Pgp), a drug efflux transporter which contributes to multidrug resistance.…”

“…In particular, therapies to target the treatment-resistant populations associated with hypoxic niches are much sought after. Some CAIX/XII-selective compounds based on the sulfamate or benzenesulfonamide scaffold inhibit proliferation and increase apoptosis of different cancer cells in normoxic conditions [18,45] or more prominent under hypoxic conditions [15,17,32,46]. The increased apoptosis is associated with a reduced expression of CAIX, suggesting that apoptosis is induced in high CAIX expressing cells.…”

Inhibitory activity against carbonic anhydrase IX and XII as a candidate selection criterion in the development of new anticancer agents

“…Arguably, h CA XII is widely distributed in the human body and considered a marker for less malignant tumours 11 . Targeting the catalytic activity of the cell surface carbonic anhydrases has been and continues to be considered a promising therapeutic approach in the antineoplastic field, either for suppressing tumour growth or overcoming drug resistance of cancer cells 12 , 13 . …”