Tumor-associated Carbonic Anhydrase Research Articles

Novel 3-substituted coumarins inspire a custom pharmacology prediction pipeline: an anticancer discovery adventure.

Aim: This research aims to expand the established pharmacological space of tumor-associated carbonic anhydrases (TACAs) by exploring the synthetically accessible chemical space of 3-substituted coumarins, with the help of insilico pharmacology prediction.Materials & methods: 52 novel 3-substituted coumarins were sketched, prioritizing synthetic feasibility. Their pharmacological potentials were estimated using a custom machine-learning approach. 17 compounds were predicted as cytotoxic against HeLa cells by interfering with TACAs. Those compounds were synthesized and biologically tested against HeLa cells. The three most potent compounds were assayed against multiple carbonic anhydrases, and their enzyme binding mechanism(s) were studied using molecular docking.Results: Experimental results exhibited pronounced consensus with in silico pharmacology predictions.Conclusion: Novel 3-substituted coumarins are herein dispatched to the cancer therapeutics space.

Discovery of new sulfonamide-tethered 2-aryl-4-anilinoquinazolines as the first-in-class dual carbonic anhydrase and EGFR inhibitors

In today's medical field, there is a growing trend of exploiting a single small molecule to target two different molecular targets concurrently. This approach is proving to be highly effective in fighting against cancer. The 4-anilinoquinazoline scaffold, known for its potential in cancer therapy and its effectiveness as a leading class of tyrosine kinase inhibitors, was employed to develop a novel series of anilinoquinazoline-sulfonamides (AQSs) (8a-d, 9a-f, and 10a-d) as dual inhibitors of the tumor-associated carbonic anhydrases (CA) IX/XII and EGFR. 2-(3-Methoxyphenyl)quinazoline bearing p-sulfanilamide 10b elicited superior hCA IX and XII inhibition in the low nanomolar range (KIs = 38.4 and 8.9 nM, respectively). Also, 10b shined as a potent and selective EGFR inhibitor, boasting an impressive IC50 value of 51.2 ± 0.97 nM, surpassing the reference EGFR inhibitor Erlotinib (IC50 = 80 ± 2.0 nM). Compound 10b exhibited broadest-spectrum antiproliferative activity against the NCI-tumor panel with a mean GI% value of 68 %. Of special interest, 10b demonstrated potent growth inhibition (GI% ≥ 80–97 %) toward cell lines reported to express high levels of EGFR belonging to renal, colon, breast, and lung cancers. Compound 10b's molecular docking in the CA IX/XII and EGFR active sites revealed binding modes that justify its potent enzyme inhibitory effects. Additionally, molecular dynamic simulations demonstrated strong and stable interactions of 10b with the binding sites of these targets.

Glucoimines incorporating classical and non-classical carbonic anhydrase pharmacophores: Design, synthesis, conformational analysis, biological evaluation, and docking simulations

In this report, a series of glucoimines has been prepared by reaction of d-glucosamine and aromatic aldehydes incorporating classical and non-classical carbonic anhydrase pharmacophores. The conformational behavior of veratrole glucoimine was studied in solution and in crystalline form, by NMR and X-ray diffraction analysis, which revealed that pyranose ring adopted a 4C1 conformation. All glucoimines were tested against four isozymes of carbonic anhydrase: hCAs I and II (cytosolic, ubiquitous isozymes) and hCAs IX and XII (tumor-associated isozymes). In this study, per-O-acetylated and deprotected sulfonamide were identified as potent inhibitors of tumor-associated carbonic anhydrase isoforms. Molecular docking simulation was performed inside the active site of hCA II to evaluate the binding modes of veratrole and sulfonamide glucoimines. The last ones demonstrated the most favorable docking scores, indicating strong binding affinity towards hCAII in correlation with experimental inhibition activities. Interestingly, interaction analyses revealed distinct binding modes for ligand-hCAII complexes primarily due to the sulfonamide group.

1,3-Diaryl Triazenes Incorporating Disulfonamides Show Both Antiproliferative Activity and Effective Inhibition of Tumor-associated Carbonic Anhydrases IX and XII.

The aim of this study was to synthesize a library of novel di-sulfa drugs containing 1,3- diaryltriazene derivatives TS (1-13) by conjugation of diazonium salts of primary sulfonamides with sulfa drugs to investigate the cytotoxic effect of these new compounds in different cancer types and to determine their inhibitory activity against tumor-associated carbonic anhydrases IX and XII. A carbonic anhydrase inhibitory activity of the obtained compounds was evaluated against four selected human carbonic anhydrase isoforms (hCA I, hCA II, hCA IX and hCA XII) by a stoppedflow CO2 hydrase assay. In addition, in vitro, cytotoxicity studies were applied by using A549 (lung cancer), BEAS-2B (normal lung), MCF-7 (breast cancer), MDA-MB-231 (breast cancer), CRL-4010 (normal breast epithelium), HT-29 (colon cancer), and HCT -116 (colon cancer) cell lines. As a result of the inhibition data, the 4-aminobenzenesulfonamide derivatives were more active than their 3-aminobenzenesulfonamide counterparts. More specifically, compounds TS-1 and TS-2, both of which have primary sulfonamides on both sides of the triazene linker, showed the best inhibitory activity against hCA IX with Ki values of 19.5 and 13.7 nM and also against hCA XII with Ki values of 6.6 and 8.3 nM, respectively. In addition, in vitro cytotoxic activity on the human breast cancer cell line MCF-7 showed that some derivatives of di-sulfa triazenes, such as TS-5 and TS-13, were more active than SLC-0111. With the aim of developing more potent and isoform-selective CA inhibitors, these novel hybrid molecules containing sulfa drugs, triazene linkers, and the classical primary sulfonamide chemotype may be considered an interesting example of effective enzyme inhibitors and important anticancer agents.

Isocoumarins incorporating chalcone moieties act as isoform selective tumor-associated carbonic anhydrase inhibitors.

Aim: A series of isocoumarin-chalcone hybrids were prepared and assays for the inhibition of four isoforms of human carbonic anhydrase (hCA; EC 4.2.1.1), hCA I, II, IX and XII. Materials & methods: Isocoumarin-chalcone hybrids were synthesized by condensing acetyl-isocoumarin with aromatic aldehydes. They did not significantly inhibit off-target cytosolic isoforms hCA I and II (KI>100μM) but acted as low micromolar or submicromolar inhibitors for the tumor-associated isoforms hCA IX and XII. Results & conclusion: Our work provides insights into a new and scarcely investigated chemotype which provides interesting tumor-associated CA inhibitors, considering that some such derivatives like sulfonamide SLC-0111 are in advanced clinical trials for the management of metastatic advanced solid tumors.

Exploring the potency of diazo-coumarin containing hybrid molecules: Selective inhibition of tumor-associated carbonic anhydrase isoforms IX and XII.

This study introduces a series of ten hybrid molecules DK(1-10), which combine diazo and coumarin moieties along with diverse aromatic substitutions. The primary objective was to evaluate the inhibitory capabilities of these compounds against four prominent isoforms: the cytosolic hCA I and II, as well as the tumor-associated membrane-bound hCA IX and XII. Impressively, the majority of the tested compounds exhibited significant inhibition activity against the tumor-associated isoforms hCA IX and XII, with KI values ranging from 29.2 to 293.3 nM. Notably, compound DK-8 displayed particularly robust inhibitory activity against the tumor-associated membrane-bound isoforms, hCA IX and XII, yielding KI values of 32.5 and 29.2 nM, respectively. Additionally, another derivative, DK-9, containing a primary sulfonamide, exhibited notable inhibition against hCA XII with a KI value of 36.4 nM. This investigation aimed to explore the structure-activity relationships within these compounds, shedding light on how various substitutions and structural components influence their inhibitory potential. As a result, these compounds present promising candidates for further exploration in medicinal and pharmacological research. Their ability to selectively inhibit specific isoforms, particularly those associated with hypoxic tumors, suggests their potential as foundational compounds for the development of novel therapeutic agents.

Co-vulnerabilities of inhibiting carbonic anhydrase IX in ferroptosis-mediated tumor cell death

The tumour-associated carbonic anhydrases (CA) IX and XII are upregulated by cancer cells to combat cellular and metabolic stress imparted by hypoxia and acidosis in solid tumours. Owing to its tumour-specific expression and function, CAIX is an attractive therapeutic target and this has driven intense efforts to develop pharmacologic agents to target its activity, including small molecule inhibitors. Many studies in multiple solid tumour models have demonstrated that targeting CAIX activity with the selective CAIX/XII inhibitor, SLC-0111, results in anti-tumour efficacy, particularly when used in combination with chemotherapy or immune checkpoint blockade, and has now advanced to the clinic. However, it has been observed that sustainability and durability of CAIX inhibition, even in combination with chemotherapy agents, is limited by the occurrence of adaptive resistance, resulting in tumour recurrence. Importantly, the data from these models demonstrates that CAIX inhibition may sensitize tumour cells to cytotoxic drugs and evidence now points to ferroptosis, an iron-dependent form of regulated cell death (RCD) that results from accumulation of toxic levels of phospholipid peroxidation as a major mechanism involved in CAIX-mediated sensitization to cancer therapy. In this mini-review, we discuss recent advances demonstrating the mechanistic role CAIX plays in sensitizing cancer cells to ferroptosis.

Investigation of the effect of CA IX enzyme inhibition on the EZH2 gene and histone 3 modifications

Abstract Objectives Colon cancer is the most common gastrointestinal cancer worldwide with high morbidity and mortality rates. The main purpose of our study is to elucidate the interaction mechanism of the H+ ion concentration effect in the CO2/HCO3 − buffer system of tumor-associated carbonic anhydrase IX (CA IX) enzyme inhibition in the HT-29 colon cancer cell line on cell epigenetic modifications. Methods Cell culture was performed using the human colon cancer cell line HT-29. CA IX enzyme inhibitor Acetazolamide (AZA) was administered. The results of the cell viability test and inhibition were evaluated. Extracellular pH measurements were performed. Total histone protein isolation was performed and Histone H3 modifications were analyzed by ELISA method. After RNA isolation, complementary DNA (cDNA) synthesis was carried out. RT-PCR was performed to determine the gene expression levels of hypoxia-inducible factor 1A (HIF1A), enhancer of zeste homolog 2 (EZH2) and CA IX. Results CA IX enzyme inhibition in the HT-29 cell line decreased the expression of CA IX (p<0.05) and HIF1A (p<0.01) genes and increased the expression of the EZH2 (p<0.05). There was a significant decrease in the expression of CA IX (p<0.05) and HIF1A genes as a result of inhibition with AZA performed under hypoxic conditions. It was observed that CA IX enzyme inhibition increases the expression of the EZH2 gene by more than 3 times (p<0.01). As a result of AZA inhibition, methylation levels were observed to increase in normoxic conditions, while methylation levels were observed to decrease in hypoxic conditions. Conclusions Observing the changes in the H3 modifications and changes in the expression of CA IX, HIF1A and EZH2 genes in this study supports that CA IX enzyme inhibition plays an active role in epigenetic modifications.

Potent inhibitors of tumor associated carbonic anhydrases endowed with cathepsin B inhibition.

Twenty-one novel extended analogs of acetazolamide were synthesized and screened in vitro for their inhibition efficacy against human carbonic anhydrase (hCA) isoforms I, II, IX, XII, and cathepsin B. The majority of the compounds were found to be effective inhibitors of tumor-associated hCA IX and XII, and poor inhibitors of cytosolic hCA I. Despite the strong to moderate inhibition potential possessed by these compounds toward another cytosolic isoform hCA II, some of them demonstrated better potency against hCA IX and/or XII isoforms as compared to hCA II. Four compounds (11f, 11g, 12c, and 12g) effectively inhibited hCA IX and/or XII isoforms with considerable selectivity over the off-targets hCA I and II. Interestingly, five compounds,including 11f, 11g, 12c, 12d, and 12g, inhibited hCA IX even better than the clinically used acetazolamide. Some of the novel synthesized compounds exhibited higher anti-cathepsin B potential than acetazolamide, with % inhibition of around 50%, at a concentration of 10-7 M. Further, two compounds (12g and 12c) that showed effective and selective inhibition activity profiles against hCA IX and XII were additionally found to be effective inhibitors of cathepsin B.

First clinical experience with fractionated intracavitary radioimmunotherapy using [177Lu]Lu-6A10-Fab fragments in patients with glioblastoma: a pilot study

BackgroundFollowing resection and standard adjuvant radio- and chemotherapy, approved maintenance therapies for glioblastoma are lacking. Intracavitary radioimmunotherapy (iRIT) with 177Lu-labeled 6A10-Fab fragments targeting tumor-associated carbonic anhydrase XII and injected into the resection cavity offers a novel and promising strategy for improved tumor control.MethodsThree glioblastoma patients underwent tumor resection followed by standard radio- and chemotherapy. These patients with stable disease following completion of standard therapy underwent iRIT on compassionate grounds. After surgical implantation of a subcutaneous injection reservoir with a catheter into the resection cavity, a leakage test with [99mTc]Tc-DTPA was performed to rule out leakage into other cerebral compartments. IRIT comprised three consecutive applications over three months for each patient, with 25%, 50%, 25% of the total activity injected. A dosimetry protocol was included with blood sampling and SPECT/CT of the abdomen to calculate doses for the bone marrow and kidneys as potential organs at risk.ResultsAll three patients presented without relevant leakage after application of [99mTc]Tc-DTPA. Two patients underwent three full cycles of iRIT (592 MBq and 1228 MBq total activity). One patient showed histologically proven tumor progression after the second cycle (526 MBq total activity). No relevant therapy-associated toxicities or adverse events were observed. Dosimetry did not reveal absorbed doses above upper dose limits for organs at risk.ConclusionsIn first individual cases, iRIT with [177Lu]Lu-6A10-Fab appears to be feasible and safe, without therapy-related side effects. A confirmatory multicenter phase-I-trial was recently opened and is currently recruiting.

Coumarin-pyrazoline Hybrids as Selective Inhibitors of the Tumor-associated Carbonic Anhydrase IX and XII.

Human carbonic anhydrase (CA, EC 4.2.1.1) isoforms IX and XII are validated antitumor/ antimetastatic drug and tumor imaging targets with sulfonamide inhibitors and monoclonal antibodies in clinical development. Coumarins act as isoform-selective inhibitors of these isoforms over the cytosolic and mitochondrial ones. We report the synthesis and in vitro CA inhibitory evaluation of a large panel of coumarins incorporating pyrazole-1-carboxamide moieties. Compounds were fully characterized before the assessment of their inhibitory activity. A stopped-flow CO2 hydrase assay was performed for the biological test. These coumarins did not inhibit the widespread, off-target isoforms CA I and II (KI >50 μM), but they were sub-micromolar CA IX/XII inhibitors with an interesting selectivity index higher than the reference compound. Selectivity between α- and β-class of CAs was also promising. These compounds may be used as leads for the rational design and development of non-sulfonamide CA IX/XII effective inhibitors.

Coumarin and Piperazine Conjugates as Selective Inhibitors of the Tumor-associated Carbonic Anhydrase IX and XII Isoforms.

Carbonic Anhydrases (CAs) are a family of metalloenzymes that catalyze the reversible interconversion of CO2 and water to bicarbonate and proton. CA isoforms I, II, IX, and XII are considered physiologically and pharmacologically relevant. The objective of this study is to synthesize potent and selective tumor-associated CA IX and XII inhibitors. A library of 17 coumarin derivatives clubbed with piperazine and benzyl moiety was designed, synthesized and evaluated for its inhibitory effects and selectivity profile towards physiologically and pharmacologically relevant CA isoforms I, II, IX, and XII. All the derivatives were found to be active against the tumor-associated isoforms IX and XII. The most active compound against hCA (human Carbonic Anhydrase) IX was found to possess a Ki of 229 nM, while the one against hCA XII had a Ki of 294.2 nM. Additionally, two of the compounds were found to have exquisite selectivity towards the off-target hCA I and II isoforms. Moreover, they were found to be approximately 20-fold more selective towards hCA IX than XII. The selectivity of the compounds was further investigated via molecular modeling techniques. Coumarin-piperazine hybrids were identified as potent and selective CA IX and XII inhibitors. Molecular modeling techniques provided interesting cues pertaining to observed selectivity.

Conformationally Restricted Glycoconjugates Derived from Arylsulfonamides and Coumarins: New Families of Tumour-Associated Carbonic Anhydrase Inhibitors.

The involvement of carbonic anhydrases (CAs) in a myriad of biological events makes the development of new inhibitors of these metalloenzymes a hot topic in current Medicinal Chemistry. In particular, CA IX and XII are membrane-bound enzymes, responsible for tumour survival and chemoresistance. Herein, a bicyclic carbohydrate-based hydrophilic tail (imidazolidine-2-thione) has been appended to a CA-targeting pharmacophore (arylsulfonamide, coumarin) with the aim of studying the influence of the conformational restriction of the tail on the CA inhibition. For this purpose, the coupling of sulfonamido- or coumarin-based isothiocyanates with reducing 2-aminosugars, followed by the sequential acid-promoted intramolecular cyclization of the corresponding thiourea and dehydration reactions, afforded the corresponding bicyclic imidazoline-2-thiones in good overall yield. The effects of the carbohydrate configuration, the position of the sulfonamido motif on the aryl fragment, and the tether length and substitution pattern on the coumarin were analysed in the in vitro inhibition of human CAs. Regarding sulfonamido-based inhibitors, the best template turned out to be a d-galacto-configured carbohydrate residue, meta-substitution on the aryl moiety (9b), with Ki against CA XII within the low nM range (5.1 nM), and remarkable selectivity indexes (1531 for CA I and 181.9 for CA II); this provided an enhanced profile in terms of potency and selectivity compared to more flexible linear thioureas 1-4 and the drug acetazolamide (AAZ), used herein as a reference compound. For coumarins, the strongest activities were found for substituents devoid of steric hindrance (Me, Cl), and short linkages; derivatives 24h and 24a were found to be the most potent inhibitors against CA IX and XII, respectively (Ki = 6.8, 10.1 nM), and also endowed with outstanding selectivity (Ki > 100 µM against CA I, II, as off-target enzymes). Docking simulations were conducted on 9b and 24h to gain more insight into the key inhibitor-enzyme interactions.

Arylidine extensions of 3-methyl-5-oxo-4,5-dihydro-1H-pyrazol-benzenesulfonamide derivatives: Synthesis, computational simulations and biological evaluation as tumor-associated carbonic anhydrase inhibitors

Several pyrazole-benzene sulfonamides were reported as human carbonic anhydrase inhibitors. In this research work, a design of Arylidine-extented 5-oxo-pyrazole benzenesulfonamides (4a-i), (8a-d) and (10a-e) were reported based on tail-approach design. Beside the reported synthetic procedures and confirmation by different analytical procedures, a DFT study was employed to confirm the Z- conformer of the synthesized compounds. In vitro biological assay against four different human carbonic anhydrases took place and based on the results, SAR study was illustrated and selectivity indexes were discussed. Compounds 4g and 8a exhibited the best inhibitory activity among the target compounds with values (hCAIX: KI = 71.2 nM, hCAXII: KI = 22.5 nM), (hCAIX: KI = 34.3 nM, hCAXII: KI = 74.3 nM); respectively. Both of them were subjected to cellular assay against two different cancer cell lines with expressing nature to hCA isoforms under both normoxic and hypoxic conditions. Compound 4g showed the highest cytotoxic activity against MCF-7 cancer cell line (IC50 = 4.15 µM under hypoxic conditions and IC50 = 8.59 µM under normoxic conditions) compared to the reference drug doxorubicin under normoxic, (IC50 = 4.34 µM), and hypoxic, (IC50 = 2.23 µM), conditions. Further cellular investigations were employed to study the effect of this compound on the cell cycle of the affected cell line. Finally, molecular docking supported by molecular dynamic simulation was utilized to understand the mechanism of the inhibitory activity of two of these compounds – as representative examples- based on the designed rational.

Differential CMS-Related Expression of Cell Surface Carbonic Anhydrases IX and XII in Colorectal Cancer Models-Implications for Therapy.

Tumor-associated carbonic anhydrases IX (CAIX) and XII (CAXII) have long been in the spotlight as potential new targets for anti-cancer therapy. Recently, CAIX/CAXII specific inhibitor SLC-0111 has passed clinical phase I study and showed differential response among patients with colorectal cancer (CRC). CRC can be classified into four different consensus molecular subgroups (CMS) showing unique expression patterns and molecular traits. We questioned whether there is a CMS-related CAIX/CAXII expression pattern in CRC predicting response. As such, we analyzed transcriptomic data of tumor samples for CA9/CA12 expression using Cancertool. Protein expression pattern was examined in preclinical models comprising cell lines, spheroids and xenograft tumors representing the CMS groups. Impact of CAIX/CAXII knockdown and SLC-0111 treatment was investigated in 2D and 3D cell culture. The transcriptomic data revealed a characteristic CMS-related CA9/CA12 expression pattern with pronounced co-expression of both CAs as a typical feature of CMS3 tumors. Protein expression in spheroid- and xenograft tumor tissue clearly differed, ranging from close to none (CMS1) to strong CAIX/CAXII co-expression in CMS3 models (HT29, LS174T). Accordingly, response to SLC-0111 analyzed in the spheroid model ranged from no (CMS1) to clear (CMS3), with moderate in CMS2 and mixed in CMS4. Furthermore, SLC-0111 positively affected impact of single and combined chemotherapeutic treatment of CMS3 spheroids. In addition, combined CAIX/CAXII knockdown and more effective treatment with SLC-0111 reduced clonogenic survival of CMS3 modelling single cells. In conclusion, the preclinical data support the clinical approach of targeted CAIX/CAXII inhibition by showing linkage of expression with response and suggest that patients with CMS3-classified tumors would most benefit from such treatment.

Selective carbonic anhydrase IX and XII inhibitors based around a functionalized coumarin scaffold.

Inhibition of specific carbonic anhydrase (CA) enzymes is a validated strategy for the development of agents to target cancer. The CA isoforms IX and XII are overexpressed in various human solid tumors wherein they play a critical role in regulating extracellular tumor acidification, proliferation, and progression. A series of novel sulfonamides based on the coumarin scaffold were designed, synthesized and characterized as potent and selective CA inhibitors. Selected compounds show significant activity and selectivity over CA I and CA II to target the tumor-associated CA IX and CA XII with high inhibition activity at the single digit nanomolar level. Twelve compounds were identified to be more potent compared with acetazolamide (AAZ) control to inhibit CA IX while one was also more potent than AAZ to inhibit CA XII. Compound 18f (Ki's = 955 nM, 515 nM, 21 nM and 5 nM for CA's I, II, IX, and XII, respectively) is highlighted as a novel CA IX and XII inhibitor for further development.

DDEL-09. FRACTIONATED INTRACAVITARY RADIOIMMUNOTHERAPY WITH LU-177 LABELED 6A10 FAB FRAGMENTS IN PATIENTS WITH GLIOBLASTOMA

Abstract Background Radio-immunotherapy (RIT) with Lu- 177 labeled 6A10-Fab fragments, targeting tumor-associated carbonic anhydrase XII (CA12) and applied directly into the resection cavity, offers a promising strategy to address hibernating tumor burden after resection and completion of adjuvant treatment for glioblastoma. We report on the first in human applications. METHODS Three patients underwent microsurgical resection of glioblastoma. After completion of adjuvant radio- and chemotherapy, RIT was offered in a compassionate use setting. After implantation of an injection reservoir into the tumor cavity, three consecutive doses of Lu-177 labeled 6A10 Fab fragments were administered over three months, corresponding to 25% - 50% - 25% of the total activity. The injected dose was adapted to the size of the resection cavity. Dosimetry was performed with planar whole-body scintigraphy and SPECT/CT 12h, 24h, 48h, 76h and 5-7 days after injection. RESULTS Patient 1 (IDH1-Mutation) received three doses of RIT (total of 592 MBq) with stable disease 12 months after therapy and 26 months after initial diagnosis. Patient 2(IDH-Wildtype) had histologically proven tumor progression after the second cycle (total of 526 MBq). Patient 3 (IDH-Wildtype) has so far received one cycle of RIT (327 MBq of a planned total of 1300 MBq). No toxicity according to CTCAE version 6.0 or other adverse events related to RIT were observed. Dosimetry did not reveal absorbed doses above the upper dose limits for organs at risk. Conclusions Intracavitary radioimmunotherapy with Lu-177 labeled 6A10-Fab fragments appears to be a safe maintenance therapy for glioblastoma patients, albeit only assessed in three compassionate use situations far. A multicenter confirmatory phase-I-trial will be was initiated in May 2022 (EudraCT-No: 2015-004417-25) to determine the maximum tolerated dose and safety of adjuvant RIT with Lu-177 labeled 6A10-Fab fragments.

Development of benzene and benzothiazole-sulfonamide analogues as selective inhibitors of the tumor-associated carbonic anhydrase IX

With an aim to develop novel potential antitumor agents, two series of benzene- and benzothiazole-sulfonamide derivatives, acting as effective human carbonic anhydrase (hCA, EC 4.2.1.1) inhibitors, have been developed using the tail approach. The synthesized compounds (XS-1 to XS-22) were assayed for the inhibition of physiologically relevant isoforms of hCA, the cytosolic CA I and II, the membrane-bound CA IV and tumor-associated CA IX. It was found the compounds of both series displayed low to medium nanomolar range inhibition against CA I, II and IX, and weak inhibition against CA IV. Some of the derivatives displayed selective inhibition towards tumor-associated CA IX isoform, within the nanomolar range. These potent compounds were also screened for their selective toxicity to evaluate their in vitro anti-proliferative effects on Human Gingival Fibroblasts (HGFs) and breast adenocarcinoma cell line (MCF7). Lastly, molecular docking studies were carried out to explain those structural requirements that were liable for the discrimination among selected human carbonic anhydrase isoforms.

Carbonic anhydrase XII as biomarker and therapeutic target in ovarian carcinomas.

Targeting the tumor-associated carbonic anhydrase XII (CA XII) is considered a promising strategy to improve cancer treatment. As such progress is highly demanded for ovarian carcinomas, the present study aimed to provide deeper information about their CA XII expression profile. A large collection of tissue specimens was stained immunohistochemically with a specific anti-CA XII antibody to evaluate the expression in neoplastic and non-neoplastic epithelial ovarian cells. In addition, flow cytometry was used to measure CA XII expression on tumor cells from malignant ascites fluid. Binding of the antibody revealed a significant CA XII expression in most ovarian carcinoma tissue samples and ascites-derived ovarian carcinoma cells. Moreover, CA XII was expressed at higher levels in ovarian carcinomas as compared to borderline ovarian tumors and non-neoplastic ovarian epithelia. Within the carcinoma tissues, high expression of CA XII was associated with higher tumor grading and a trend towards shorter overall survival. Our results indicate that CA XII plays a crucial role for the malignancy of ovarian carcinoma cells and emphasize the potential of CA XII as a diagnostic marker and therapeutic target in the management of ovarian carcinomas.

Squaramide-Tethered Sulfonamides and Coumarins: Synthesis, Inhibition of Tumor-Associated CAs IX and XII and Docking Simulations.

(1) Background: carbonic anhydrases (CAs) are attractive targets for the development of new anticancer therapies; in particular, CAs IX and XII isoforms are overexpressed in numerous tumors. (2) Methods: following the tail approach, we have appended a hydrophobic aromatic tail to a pharmacophore responsible for the CA inhibition (aryl sulfonamide, coumarin). As a linker, we have used squaramides, featured with strong hydrogen bond acceptor and donor capacities. (3) Results: Starting from easily accessible dimethyl squarate, the title compounds were successfully obtained as crystalline solids, avoiding the use of chromatographic purifications. Interesting and valuable SARs could be obtained upon modification of the length of the hydrocarbon chain, position of the sulfonamido moiety, distance of the aryl sulfonamide scaffold to the squaramide, stereoelectronic effects on the aromatic ring, as well as the number and type of substituents on C-3 and C-4 positions of the coumarin. (4) Conclusions: For sulfonamides, the best profile was achieved for the m-substituted derivative 11 (Ki = 29.4, 9.15 nM, CA IX and XII, respectively), with improved selectivity compared to acetazolamide, a standard drug. Coumarin derivatives afforded an outstanding selectivity (Ki > 10,000 nM for CA I, II); the lead compound (16c) was a strong CA IX and XII inhibitor (Ki = 19.2, 7.23 nM, respectively). Docking simulations revealed the key ligand-enzyme interactions.