Ureido-substituted benzenesulfonamides potently inhibit carbonic anhydrase IX and show antimetastatic activity in a model of breast cancer metastasis

Development of a multi-targeted chemotherapeutic approach based on G-quadruplex stabilisation and carbonic anhydrase inhibition

A novel class of compounds designed to hit two anti-tumour targets, G-quadruplex structures and human carbonic anhydrases (hCAs) IX and XII is proposed. The induction/stabilisation of G-quadruplex structures by small molecules has emerged as an anticancer strategy, disrupting telomere maintenance and reducing oncogene expression. hCAs IX and XII are well-established anti-tumour targets, upregulated in many hypoxic tumours and contributing to metastasis. The ligands reported feature a berberine G-quadruplex stabiliser scaffold connected to a moiety inhibiting hCAs IX and XII. In vitro experiments showed that our compounds selectively stabilise G-quadruplex structures and inhibit hCAs IX and XII. The crystal structure of a telomeric G-quadruplex in complex with one of these ligands was obtained, shedding light on the ligand/target interaction mode. The most promising ligands showed significant cytotoxicity against CA IX-positive HeLa cancer cells in hypoxia, and the ability to stabilise G-quadruplexes within tumour cells.

Discovery of novel 1,8-naphthalimide piperazinamide based benzenesulfonamides derivatives as potent carbonic anhydrase IX inhibitors and ferroptosis inducers for the treatment of triple-negative breast cancer

A novel series of 1,8-naphthalimide piperazinamide based benzenesulfonamides derivatives were designed and synthesized as carbonic anhydrase IX (CA IX) inhibitors and ferroptosis inducers for the treatment of triple-negative breast cancer (TNBC). The representative compound 9o exhibited more potent inhibitory activity and selective against CA IX over off-target CA II, compared with positive control SLC-0111. Molecular docking study was also performed to gain insights into the binding interactions of 9o in the binding pocket of CAIX. Moreover, compound 9o exhibited superior antitumor activities against breast cancer cells under hypoxia than that of normoxia conditions. Mechanism studies revealed that compound 9o could act as DNA intercalator and effectively suppressed cell migration, arrested the cell cycle at G1/S phase and induced apoptosis in MDA-MB-231 cells, while inducing ferroptosis accompanied by the dissipation of MMP and the elevation intracellular levels of ROS. Notably, in vivo studies demonstrated that 9o effectively inhibited tumor growth and metastasis in a highly metastatic murine breast cancer 4 T1 xenograft model. Taken together, this study suggests that compound 9o represents a potent and selective CA IX inhibitor and ferroptosis inducer for the treatment of TNBC.

IL-22 regulates MASTL expression in intestinal epithelial cells

Microtubule-associated serine-threonine kinase-like (MASTL) has recently been identified as an oncogenic kinase given its overexpression in numerous cancers. Our group has shown that MASTL expression is upregulated in mouse models of sporadic colorectal cancer and colitis-associated cancer (CAC). CAC is one of the most severe complications of chronic inflammatory bowel disease (IBD), but a limited understanding of the mechanisms governing the switch from normal healing to neoplasia in IBD underscores the need for increased research in this area. However, MASTL levels in patients with IBD and its molecular regulation in IBD and CAC have not been studied. This study reveals that MASTL is upregulated by the cytokine interleukin (IL)-22, which promotes proliferation and has important functions in colitis recovery; however, IL-22 can also promote tumorigenesis when chronically elevated. Upon reviewing the publicly available data, we found significantly elevated MASTL and IL-22 levels in the biopsies from patients with late-stage ulcerative colitis compared with controls, and that MASTL upregulation was associated with high IL-22 expression. Our subsequent in vitro studies found that IL-22 increases MASTL expression in intestinal epithelial cell lines, which facilitates IL-22-mediated cell proliferation and downstream survival signaling. Inhibition of AKT activation abrogated IL-22-induced MASTL upregulation. We further found an increased association of carbonic anhydrase IX (CAIX) with MASTL in IL-22-treated cells, which stabilized MASTL expression. Inhibition of CAIX prevented IL-22-induced MASTL expression and cell survival. Overall, we show that IL-22/AKT signaling increases MASTL expression to promote cell survival and proliferation. Furthermore, CAIX associates with and stabilizes MASTL in response to IL-22 stimulation.NEW & NOTEWORTHY MASTL is upregulated in colorectal cancer; however, its role in colitis and colitis-associated cancer is poorly understood. This study is the first to draw a link between MASTL and IL-22, a proinflammatory/intestinal epithelial recovery-promoting cytokine that is also implicated in colon tumorigenesis. We propose that IL-22 increases MASTL protein stability by promoting its association with CAIX potentially via AKT signaling to promote cell survival and proliferation.

Carbonic anhydrase IX: An atypical target for innovative therapies in cancer

Carbonic anhydrases (CAs), are metallo-enzymes implicated in several pathophysiological processes where tissue pH regulation is required. CA IX is a tumor-associated CA isoform induced by hypoxia and involved in the adaptation of tumor cells to acidosis. Indeed, several tumor-driving pathways can induce CA IX expression, and this in turn has been associated to cancer cells invasion and metastatic features as well as to induction of stem-like features, drug resistance and recurrence. After its functional and structural characterization CA IX targeting approaches have been developed to inhibit its activity in neoplastic tissues, and to date this field has seen an incredible acceleration in terms of therapeutic options and biological readouts. Small molecules inhibitors, hybrid/dual targeting drugs, targeting antibodies and adoptive (CAR-T based) cell therapy have been developed at preclinical level, whereas a sulfonamide CA IX inhibitor and an antibody entered Phase Ib/II clinical trials for the treatment and imaging of different solid tumors. Here recent advances on CA IX biology and pharmacology in cancer, and its therapeutic targeting will be discussed.

Identification and characterization of a new potent inhibitor targeting CtBP1/BARS in melanoma cells

BACKGROUND

The C-terminal-binding protein 1/brefeldin A ADP-ribosylation substrate (CtBP1/BARS) acts both as an oncogenic transcriptional co-repressor and as a fission inducing protein required for membrane trafficking and Golgi complex partitioning during mitosis, hence for mitotic entry. CtBP1/BARS overexpression, in multiple cancers, has pro-tumorigenic functions regulating gene networks associated with "cancer hallmarks" and malignant behavior including: increased cell survival, proliferation, migration/invasion, epithelial-mesenchymal transition (EMT). Structurally, CtBP1/BARS belongs to the hydroxyacid-dehydrogenase family and possesses a NAD(H)-binding Rossmann fold, which, depending on ligands bound, controls the oligomerization of CtBP1/BARS and, in turn, its cellular functions. Here, we proposed to target the CtBP1/BARS Rossmann fold with small molecules as selective inhibitors of mitotic entry and pro-tumoral transcriptional activities.

METHODS

Structured-based screening of drug databases at different development stages was applied to discover novel ligands targeting the Rossmann fold. Among these identified ligands, N-(3,4-dichlorophenyl)-4-{[(4-nitrophenyl)carbamoyl]amino}benzenesulfonamide, called Comp.11, was selected for further analysis. Fluorescence spectroscopy, isothermal calorimetry, computational modelling and site-directed mutagenesis were employed to define the binding of Comp.11 to the Rossmann fold. Effects of Comp.11 on the oligomerization state, protein partners binding and pro-tumoral activities were evaluated by size-exclusion chromatography, pull-down, membrane transport and mitotic entry assays, Flow cytometry, quantitative real-time PCR, motility/invasion, and colony assays in A375MM and B16F10 melanoma cell lines. Effects of Comp.11 on tumor growth in vivo were analyzed in mouse tumor model.

RESULTS

We identify Comp.11 as a new, potent and selective inhibitor of CtBP1/BARS (but not CtBP2). Comp.11 directly binds to the CtBP1/BARS Rossmann fold affecting the oligomerization state of the protein (unlike other known CtBPs inhibitors), which, in turn, hinders interactions with relevant partners, resulting in the inhibition of both CtBP1/BARS cellular functions: i) membrane fission, with block of mitotic entry and cellular secretion; and ii) transcriptional pro-tumoral effects with significantly hampered proliferation, EMT, migration/invasion, and colony-forming capabilities. The combination of these effects impairs melanoma tumor growth in mouse models.  CONCLUSIONS: This study identifies a potent and selective inhibitor of CtBP1/BARS active in cellular and melanoma animal models revealing new opportunities to study the role of CtBP1/BARS in tumor biology and to develop novel melanoma treatments.

Probing benzenesulfonamide-thiazolidinone hybrids as multitarget directed ligands for efficient control of type 2 diabetes mellitus through targeting the enzymes: α-glucosidase and carbonic anhydrase II

Diabetes mellitus is a chronic metabolic disorder characterized by improper expression/function of a number of key enzymes that can be regarded as targets for anti-diabetic drug design. Herein, we report the design, synthesis, and biological assessment of two series of thiazolidinone-based sulfonamides 4a-l and 5a-c as multitarget directed ligands (MTDLs) with potential anti-diabetic activity through targeting the enzymes: α-glucosidase and human carbonic anhydrase (hCA) II. The synthesized sulfonamides were evaluated for their inhibitory activity against α-glucosidase where most of the compounds showed good to potent activities. Compounds 4d and 4e showed potent inhibitory activities (IC50 = 0.440 and 0.3456 μM), comparable with that of the positive control (acarbose; IC50 = 0.420 μM). All the synthesized derivatives were also tested for their inhibitory activities against hCA I, II, IX, and XII. They exhibited different levels of inhibition against these isoforms. Compound 4d outstood as the most potent one against hCA II with Ki equals to 7.0 nM, more potent than the reference standard (acetazolamide; Ki = 12.0 nM). In silico studies for the most active compounds within the active sites of α-glucosidase and hCA II revealed good binding modes that can explain their biological activities. MM-GBSA refinements and molecular dynamic simulations were performed on the top-ranking docking pose of the most potent compound 4d to confirm the formation of stable complex with both targets. Compound 4d was screened for its in vivo antihyperglycemic efficacy by using the oral glucose tolerance test. Compound 4d decreased blood glucose level to 217 mg/dl, better than the standard acarbose (234 mg/dl). Hence, this revealed its synergistic mode of action on post prandial hyperglycemia and hepatic gluconeogenesis. Thus, these benzenesulfonamide thiazolidinone hybrids could be considered as promising multi-target candidates for the treatment of type II diabetes mellitus.

Effective Anticancer Potential of a New Sulfonamide as a Carbonic Anhydrase IX Inhibitor Against Aggressive Tumors

This study examines efficiency of a newly synthesized sulfonamide derivative 2-bromo-N-(4-sulfamoylphenyl)propanamide (MMH-1) on the inhibition of Carbonic Anhydrase IX (CA IX), which is overexpressed in many solid tumors including breast cancer. The inhibitory potential of MMH-1 compound against its four major isoforms, including cytosolic isoforms hCA I and II, as well as tumor-associated membrane-bound isoforms hCA IX and XII, was evaluated. To this context, the cytotoxic effect of MMH-1 on cancer and normal cells was tested and found to selectively affect MDA-MB-231 cells. MMH-1 reduced cell proliferation by holding cells in the G0/G1 phase (72 %) and slowed the cells' wound healing capacity. MMH-1 inhibited CA IX under both hypoxic and normoxic conditions and altered the morphology of triple negative breast cancer cells. In MDA-MB-231 cells, inhibition of CA IX was accompanied by a decrease in extracellular pH acidity (7.2), disruption of mitochondrial membrane integrity (80 %), an increase in reactive oxygen levels (25 %), and the triggering of apoptosis (40 %). In addition, the caspase cascade (CASP-3, -8, -9) was activated in MDA-MB-231 cells, triggering both the extrinsic and intrinsic apoptotic pathways. The expression of pro-apoptotic regulatory proteins (Bad, Bax, Bid, Bim, Cyt-c, Fas, FasL, TNF-a, TNF-R1, HTRA, SMAC, Casp-3, -8, P21, P27, and P53) was increased, while the expression of anti-apoptotic proteins, apoptosis inhibitor proteins (IAPs), and heat shock proteins (HSPs) (Bcl-2, Bcl-w, cIAP-2, HSP27, HSP60, HSP70, Survivin, Livin, and XIAP) was decreased. These results propose that the MMH-1 compound could triggers apoptosis in MDA-MB-231 cells via the pH/MMP/ROS pathway through the inhibition of CA IX. This compound is thought to have high potential and promising anticancer properties in the treatment of aggressive tumors.

Combining BNCT with carbonic anhydrase inhibition for mesothelioma treatment: Synthesis, in vitro, in vivo studies of ureidosulfamido carboranes

Mesothelioma is a malignant neoplasm of mesothelial cells caused by exposure to asbestos. The average survival time after diagnosis is usually nine/twelve months. A multi-therapeutic approach is therefore required to treat and prevent recurrence. Boronated derivatives containing a carborane cage, a sulfamido group and an ureido functionality (CA-USF) have been designed, synthesised and tested, in order to couple Boron Neutron Capture Therapy (BNCT) and the inhibition of Carbonic Anhydrases (CAs), which are overexpressed in many tumours. In vitro studies showed greater inhibition than the reference drug acetazolamide (AZ). To increase solubility in aqueous media, CA-USFs were used as inclusion complexes of hydroxypropyl β-cyclodextrin (HP-β-CD) in all the inhibition and cell experiments. BNCT experiments carried out on AB22 (murine mesothelioma) cell lines showed a marked inhibition of cell proliferation by CA-USFs, and in one case a complete inhibition of proliferation twenty days after neutron irradiation. Finally, in vivo neutron irradiation experiments on a mouse model of mesothelioma demonstrated the efficiency of combining CA IX inhibition and BNCT treatment. Indeed, a greater reduction in tumour mass was observed in treated mice compared to untreated mice, with a significant higher effect when combined with BNCT. For in vivo experiments CA-USFs were administered as inclusion complexes of higher molecular weight β-CD polymers thus increasing the selective extravasation into tumour tissue and reducing clearance. In this way, boron uptake was maximised and CA-USFs demonstrated to be in vivo well tolerated at a therapeutic dose. The therapeutic strategy herein described could be expanded to other cancers with increased CA IX activity, such as melanoma, glioma, and breast cancer.

pH regulators and their inhibitors in tumor microenvironment

As an important characteristic of tumor, acidic tumor microenvironment (TME) is closely related to immune escape, invasion, migration and drug resistance of tumor. The acidity of the TME mainly comes from the acidic products produced by the high level of tumor metabolism, such as lactic acid and carbon dioxide. pH regulators such as monocarboxylate transporters (MCTs), carbonic anhydrase IX (CA IX), and Na+/H+ exchange 1 (NHE1) expel protons directly or indirectly from the tumor to maintain the pH balance of tumor cells and create an acidic TME. We review the functions of several pH regulators involved in the construction of acidic TME, the structure and structure-activity relationship of pH regulator inhibitors, and provide strategies for the development of small-molecule antitumor inhibitors based on these targets.

Identification of thienopyrimidine derivatives tethered with sulfonamide and other moieties as carbonic anhydrase inhibitors: Design, synthesis and anti-proliferative activity

Eighteen novel compounds harboring the privileged thienopyrimidine scaffold (5a-q, and 6a),were designed based on molecular hybridization strategy. These compounds were synthesized and tested for their inhibitory activity against four different carbonic anhydrase isoforms: CA I, II, IX, and XII. Microwave and conventional techniques were applied for their synthesis. Compounds 5b, 5g, 5l, and 5p showed the highest inhibition activity against the four CA isoforms. Compound 5p exhibited promising inhibitory activity against CA II, CA IX and CA XII with KI values of8.6, 13.8, and 19 nM, respectively, relative to AAZ, where KIs = 12, 25, and 5.7 nM, respectively. Also, compound 5 l showed significant activity against the tumor-associated isoform CA IX with KI = 16.1 nM. All the newly synthesized compounds were also screened for their anticancer activity against NCI 60 cancer cell lines at a 10 µM concentration. Compound 5n showed 80.38, 83.95, and 87.39 % growth inhibition against the leukemic cell lines CCRF-CEM, HL-60 (TB), and RPMI-8226, respectively. Also, 5 h showed 87.57 % growth inhibition against breast cancer cell line MDA-MB-468; and 66.58 and 60.95 % inhibitionagainst renal cancer cell lines UO-31, and ACHN, respectively. A molecular docking studywas carried out to predict binding modes of our synthesized compounds in the binding pockets of the four carbonic anhydrase isoforms, and results revealed that compounds 5b, 5g, 5l, and 5p succeeded in mimicking the binding mode of AAZ through metal coordination with Zn+2 ion and binding to the amino acids Thr199, His94, and His96 that are critical for activity.

Novel Carbonic Anhydrase Inhibitors with Dual-Tail Core Sulfonamide Show Potent and Lasting Effects for Glaucoma Therapy

Glaucoma, a leading cause of irreversible vision loss worldwide, is characterized by elevated intraocular pressure (IOP), a well-established risk factor across all its forms. We present the design and synthesis of 39 novel carbonic anhydrase inhibitors by a dual-tailed approach, strategically crafted to interact with distinct hydrophobic and hydrophilic pockets of CA active sites. The series was investigated against the CA isoforms implicated in glaucoma (hCA II, hCA IV, and hCA XII), and the X-ray crystal structures of compounds 25a, 25f, and 26a with CA II, along with 14b in complex with a hCA XII mimic, were determined. Selected compounds (14a, 25a, and 26a) underwent evaluation for their ability to reduce IOP in rabbits with ocular hypertension. Derivative 26a showed significant potency and sustained IOP-lowering effects, surpassing the efficacy of the drugs dorzolamide and bimatoprost. This positions compound 26a as a promising candidate for the development of a novel anti-glaucoma medication.

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.

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

AIM

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.

MATERIALS AND METHODS

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.

RESULTS

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.

CONCLUSION

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.

Thiosemicarbazone-benzenesulfonamide Derivatives as Human Carbonic Anhydrases Inhibitors: Synthesis, Characterization, and In silico Studies

INTRODUCTION

Carbonic anhydrases (CAs) are widespread metalloenzymes with the core function of catalyzing the interconversion of CO2 and HCO3 -. Targeting these enzymes using selective inhibitors has emerged as a promising approach for the development of novel therapeutic agents against multiple diseases.

METHODS

A series of novel thiosemicarbazone-containing derivatives were synthesized, characterized, and tested for their inhibitory activity against pharmaceutically important human CA I (hCA I), II (hCA II), IX (hCA IX), and XII (hCA XII) using the single tail approach.

RESULTS

The compounds generally inhibited the isoenzymes at low nanomolar concentrations, with compound 6b having Ki values of 7.16, 0.31, 92.5, and 375 nM against hCA I, II, IX and XII, respectively. Compound 6e exhibited Ki values of 27.6, 0.34, 872, and 94.5 nM against hCA I, II, IX and XII, respectively.

CONCLUSION

To rationalize the inhibition data, molecular docking studies were conducted, providing insight into the binding mechanisms, molecular interactions, and selectivity of the compounds towards the isoenzymes.

Potent carbonic anhydrase I, II, IX and XII inhibition activity of novel primary benzenesulfonamides incorporating bis-ureido moieties

A novel series of twelve aromatic bis-ureido-substituted benzenesulfonamides was synthesised by conjugation of aromatic aminobenzenesulfonamides with aromatic bis-isocyanates. The obtained bis-ureido-substituted derivatives were tested against four selected human carbonic anhydrase isoforms (hCA I, hCA II, hCA IX and hCA XII). Most of the new compounds showed an effective inhibitory profile against isoforms hCA IX and hCA XII, also having some selectivity with respect to hCA I and hCA II. The inhibition constants of these compounds against isoforms hCA IX and XII were in the range of 6.73-835 and 5.02-429 nM, respectively. Since hCA IX and hCA XII are important drug targets for anti-cancer/anti-metastatic drugs, these effective inhibitors reported here may be considered of interest for cancer related studies in which these enzymes are involved.

Design, synthesis, and biological investigation of selective human carbonic anhydrase II, IX, and XII inhibitors using 7-aryl/heteroaryl triazolopyrimidines bearing a sulfanilamide scaffold

A novel library of human carbonic anhydrase (hCA) inhibitors based on the 2-sulfanilamido[1,2,4]triazolo[1,5-a]pyrimidine skeleton modified at its 7-position was prepared by an efficient convergent procedure. These derivatives were evaluated in vitro for their inhibition properties against a representative panel of hCA isoforms (hCA I, II, IV, IX, and XII). The target tumour-associated isoforms hCA IX and XII were potently inhibited with KIs in the low nanomolar range of 5-96 nM and 4-72 nM, respectively. Compounds 1d, 1j, 1v, and 1x were the most potent hCA IX inhibitors with KIs of 5.1, 8.6, 4.7, and 5.1 nM, respectively. Along with derivatives 1d and 1j, compounds 1r and 1ab potently inhibited hCA XII isoform with KIs in a single-digit nanomolar range of 8.8, 5.4, 4.3, and 9.0 nM, respectively. Compounds 1e, 1m, and 1p exhibited the best selectivity against hCA IX and hCA XII isoforms over off-target hCA II, with selectivity indexes ranging from 5 to 14.

Discovery of new 6-ureido/amidocoumarins as highly potent and selective inhibitors for the tumour-relevant carbonic anhydrases IX and XII

A series of 6-ureido/amidocoumarins (5a-p and 7a-c) has been designed and synthesised to develop potent and isoform- selective carbonic anhydrase hCA XI and XII inhibitors. All coumarin derivatives were investigated for their CA inhibitory effect against hCA I, II, IX, and XII. Interestingly, target coumarins potently inhibited both tumour-related isoforms hCA IX (K_Is: 14.7-82.4 nM) and hCA XII (K_Is: 5.9-95.1 nM), whereas the cytosolic off-target hCA I and II isoforms have not inhibited by all tested coumarins up to 100 μM. These findings granted the target coumarins an excellent selectivity profile towards both hCA IX and hCA XII isoforms, supporting their development as promising anticancer candidates. Moreover, all target molecules were evaluated for their anticancer activities against HCT-116 and MCF-7 cancer cells. The 3,5-bis-trifluoromethylphenyl ureidocoumarin 5i, exerted the best anticancer activity. Overall, ureidocoumarins, particularly compound 5i, could serve as a promising prototype for the development of potent anticancer CAIs.

2H-chromene and 7H-furo-chromene derivatives selectively inhibit tumour associated human carbonic anhydrase IX and XII isoforms

Tumour associated carbonic anhydrases (CAs) IX and XII have been recognised as potential targets for the treatment of hypoxic tumours. Therefore, considering the high pharmacological potential of the chromene scaffold as selective ligand of the IX and XII isoforms, two libraries of compounds, namely 2H-chromene and 7H-furo-chromene derivatives, with diverse substitution patterns were designed and synthesised. The structure of the newly synthesised compounds was characterised and their inhibitory potency and selectivity towards human CA off target isoforms I, II and cancer-associated CA isoforms IX and XII were evaluated. Most of the compounds inhibit CA isoforms IX and XII with no activity against the I and II isozymes. Thus, while the potency was influenced by the substitution pattern along the chromene scaffold, the selectivity was conserved along the series, confirming the high potential of both 2H-chromene and 7H-furo-chromene scaffolds for the design of isozyme selective inhibitors.

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.

4-(3-Phenyl-4-(3,4,5-trimethoxybenzoyl)-1H-pyrrol-1-yl)benzenesulfonamide, a Novel Carbonic Anhydrase and Wnt/β-Catenin Signaling Pathway Dual-Targeting Inhibitor with Potent Activity against Multidrug Resistant Cancer Cells

We synthesized new pyrrole and indole derivatives as human carbonic anhydrase (hCA) inhibitors with the potential to inhibit the Wnt/β-catenin signaling pathway. The presence of both N1-(4-sulfonamidophenyl) and 3-(3,4,5-trimethoxyphenyl) substituents was essential for strong hCA inhibitors. The most potent hCA XII inhibitor 15 (Ki = 6.8 nM) suppressed the Wnt/β-catenin signaling pathway and its target genes MYC, Fgf20, and Sall4 and exhibited the typical markers of apoptosis, cleaved poly(ADP-ribose)polymerase, and cleaved caspase-3. Compound 15 showed strong inhibition of viability in a panel of cancer cells, including colorectal cancer and triple-negative breast cancer cells, was effective against the NCI/ADR-RES DOX-resistant cell line, and restored the sensitivity to doxorubicin (DOX) in HT29/DX and MDCK/P-gp cells. Compound 15 is a novel dual-targeting compound with activity against hCA and Wnt/β-catenin. It thus has a broad targeting spectrum and is an anticancer agent with specific potential in P-glycoprotein overexpressing cell lines.

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.

Screening Campaign and Docking Investigations in Identifying New Hit Compounds as Inhibitors of Human Carbonic Anhydrases Expressed In Tumour Cells

The tumor-expressed human carbonic anhydrase (hCA) isoforms hCA IX and hCA XII have been extensively studied to develop anticancer agents targeting solid tumors in combined therapy. These CA  isoforms are considered key factors in controlling tumor microenvironment (TME) of cancer lines that develop high metastatic activity. Herein, we report the discovery of potent hCA IX/hCA XII inhibitors that were disclosed through a screening campaign on an in-house collection of arylsulfonamides preliminary tested toward other hCAs. Among them, the N-(4-sulfamoylphenyl)naphthalene-2-carboxamide (12) and N-(4-sulfamoylphenyl)-3,4-dihydroisoquinoline-2(1H)-carbothioamide (15) proved to be the most intriguing hCA IX/hCA XII inhibitors displaying favourable selectivity ratios over widespread hCA I and hCA II isoforms. To explore their binding mode, we conducted docking studies that described the poses of the best inhibitors in the catalytic site of hCA IX and hCA XII, thus suggesting the privileged pattern of interactions. These structural findings might further improve the knowledge for a successful identification of new sulfonamides as adjuvant agents in cancer management.

Potent and selective carbonic anhydrase inhibition activities of pyrazolones bearing benzenesulfonamides

This research introduces a series of fourteen 4-aryl-hydrazonopyrazolone sulfonamide derivatives, denoted as 3(a-g) and 4(a-g), which encompass various aromatic substitutions. The aim was to assess the inhibitory potential of these compounds against four significant isoforms, including the cytosolic isoforms hCA I and II, as well as the tumor-associated membrane-bound isoforms hCA IX and XII. Most of the tested compounds exhibited substantial inhibition against the tumor-associated isoform hCA IX, with Ki values spanning from 1.1 to 158.2 nM. Notably, compounds 3e and 3g showed particularly strong inhibitory activity against the tumor-associated membrane-bound isoforms, hCA IX and XII, while maintaining a high selectivity ratio over cytosolic off-target isoforms hCA I and II. This selectivity is vital due to the potential of hCA IX and hCA XII as drug targets for hypoxic tumors. In an effort to create novel analogs that exhibit enhanced carbonic anhydrase inhibitory activity and specificity, we investigated the structure-activity relationships of these compounds and provided a concise interpretation of our findings. Consequently, these compounds merit consideration for subsequent medicinal and pharmacological research, holding potential for developing novel therapeutic agents targeting specific isoforms in hypoxic tumors.

A Carbonic Anhydrase IX/SLC1A5 Axis Regulates Glutamine Metabolism Dependent Ferroptosis in Hypoxic Tumor Cells

The ability of tumor cells to alter their metabolism to support survival and growth presents a challenge to effectively treat cancers. Carbonic anhydrase IX (CAIX) is a hypoxia-induced, metabolic enzyme that plays a crucial role in pH regulation in tumor cells. Recently, through a synthetic lethal screen, we identified CAIX to play an important role in redox homeostasis. In this study, we show that CAIX interacts with the glutamine (Gln) transporter, solute carrier family 1 member 5 (SLC1A5), and coordinately functions to maintain redox homeostasis through the glutathione/glutathione peroxidase 4 (GSH/GPX4) axis. Inhibition of CAIX increases Gln uptake by SLC1A5 and concomitantly increases GSH levels. The combined inhibition of CAIX activity and Gln metabolism or the GSH/GPX4 axis results in an increase in lipid peroxidation and induces ferroptosis, both in vitro and in vivo. Thus, this study demonstrates cotargeting of CAIX and Gln metabolism as a potential strategy to induce ferroptosis in tumor cells.

Keto-bridged dual triazole-linked benzenesulfonamides as potent carbonic anhydrase and cathepsin B inhibitors

Background: Inhibition of human carbonic anhydrase (hCA) isoforms IX and XII with concurrent inhibition of cathepsin B is a promising approach for targeting cancers. Methods/results: 28 keto-bridged dual triazole-containing benzenesulfonamides were synthesized and tested, following the multitarget approach, for their efficacy as inhibitors of cathepsin B and hCA isoforms (I, II, IX, XII). The synthesized compounds showed excellent inhibition of CA isoforms (IX and XII) and cathepsin B. Compound 8i exhibited better and more selective inhibition of the cancer-associated isoform hCA IX as compared with acetazolamide (reference drug) and SLC-0111 (potent lead as carbonic anhydrase inhibitor). Molecular docking studies were also carried out. Conclusion: The present work gives important generalizations for the development of isoform-selective hCA inhibitors endowed with anti-cathepsin properties.

A simple yet multifaceted 90 years old, evergreen enzyme: Carbonic anhydrase, its inhibition and activation

Advances in the carbonic anhydrase (CA, EC 4.2.1.1) research over the last three decades are presented, with an emphasis on the deciphering of the activation mechanism, the development of isoform-selective inhibitors/ activators by the tail approach and their applications in the management of obesity, hypoxic tumors, neurological conditions, and as antiinfectives.

Novel bis-ureido-substituted sulfaguanidines and sulfisoxazoles as carbonic anhydrase and acetylcholinesterase inhibitors

To discover alternative substances to compounds used to treat many diseases, especially treating Alzheimer's disease (AD) and Parkinson's disease targeting carbonic anhydrase (hCA) and acetylcholinesterase (AChE) enzymes, is important. For this purpose, a series of novel bis-ureido-substituted sulfaguanidine (SG1-4) and sulfisoxazole (SO1-4) derivatives were synthesized, and their inhibitory capacities were screened against hCA isoenzymes (hCA I and II) and AChE. Possible binding mechanisms of inhibitors to the active site were elucidated by in silico studies, and the results were supported by in vitro results. Moreover, the percent radical scavenging capacities of the derivatives were also evaluated. The derivatives (SG1-4 and SO1-4) were more effective against hCAs compared to standard drug acetazolamide (KI values of 98.28-439.17 nM for hCA I and II, respectively) and exhibited the highest inhibition with the KIs in the ranges of 2.54 ± 0.50-41.02 ± 7.52 nM for hCA I, 11.20 ± 2.97-67.14 ± 13.58 nM for hCA II, and 257.60 ± 27.84-442.60 ± 52.13 nM for AChE. Also, compounds SG1 and SO1 also showed ABTS radical scavenging activity at the rate of 70% and 78%, respectively. These results will contribute to the literature for the rational design and synthesis of new potent and selective inhibitors targeting hCAs and AChE with multifunctional effects such as radical scavenging as well as inhibition. This study focused on the synthesis and inhibitory effects of bis-ureido-substituted sulfaguanidine (SG1-4) and sulfisoxazole (SO1-4) derivatives against human hCA I and II isoforms and AChE. In order to test synthesized derivatives' free radical scavenging potentials were the DPPH and ABTS assays. In silico studies elucidated possible binding mechanisms of inhibitors to the active site.

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: K_I = 71.2 nM, hCAXII: K_I = 22.5 nM), (hCAIX: K_I = 34.3 nM, hCAXII: K_I = 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.

Design and synthesis of 6-arylpyridine-tethered sulfonamides as novel selective inhibitors of carbonic anhydrase IX with promising antitumor features toward the human colorectal cancer

Hypoxia, a characteristic feature of solid tumors, develops as a result of excessive cell proliferation and rapid tumor growth exceeding the oxygen supply, and can result in angiogenesis activation, increased invasiveness, aggressiveness, and metastasis, leading to improved tumor survival and suppression of anticancer drug therapeutic impact. SLC-0111, a ureido benzenesulfonamide, is a selective human carbonic anhydrase (hCA) IX inhibitor in clinical trials for the treatment of hypoxic malignancies. Herein, we describe the design and synthesis of novel 6-arylpyridines 8a-l and 9a-d as structural analogues of SLC-0111, in the aim of exploring new selective inhibitors for the cancer-associated hCA IX isoform. The para-fluorophenyl tail in SLC-0111 was replaced by the privileged 6-arylpyridine motif. Moreover, both ortho- and meta-sulfonamide regioisomers, as well as an ethylene extended analogous were developed. All 6-arylpyridine-based SLC-0111 analogues were screened in vitro for their inhibitory potential against a panel of hCAs (hCA I, II, IV and IX isoforms) using stopped-flow CO₂ hydrase assay. In addition, the anticancer activity was firstly explored against a panel of 57 cancer cell lines at the USA NCI-Developmental Therapeutic Program. Compound 8g emerged as the best anti-proliferative candidate with mean GI% value equals 44. Accordingly, a cell viability assay (MTS) for 8g was applied on colorectal HCT-116 and HT-29 cancer cell lines as well as on the healthy HUVEC cells. Thereafter, Annexin V-FITC apoptosis detection, cell cycle, TUNEL, and qRT-PCR, colony formation, and wound healing assays were applied to gain mechanistic insights and to understand the behavior of colorectal cancer cells upon the treatment of compound 8g. Also, a molecular docking analysis was conducted to provide in silico insights into the reported hCA IX inhibitory activity and selectivity.

Carbonic anhydrase IX-targeted nanovesicles potentiated ferroptosis by remodeling the intracellular environment for synergetic cancer therapy

Ferroptosis is one critical kind of regulated cell death for tumor suppression, yet it still presents challenges of low efficiency due to the intracellular alkaline pH and aberrant redox status. Herein, we reported a carbonic anhydrase IX (CA IX)-targeted nanovesicle (PAHC NV) to potentiate ferroptosis by remodeling the intracellular environment. CA IX inhibitor 4-(2-aminoethyl) benzene sulfonamide (AEBS) was anchored onto nanovesicles loaded with hemoglobin (Hb) and chlorin e6 (Ce6). Upon reaching tumor regions, PAHC could be internalized by cancer cells specifically by means of CA IX targeting and intervention. Afterwards, the binding of AEBS could elicit intracellular acidification and alter redox homeostasis to boost the lipid peroxidation (LPO) level, thus aggravating the ferroptosis process. Meanwhile, Hb served as an iron reservoir that could efficiently evoke ferroptosis and release O₂ to ameliorate tumor hypoxia. With the help of self-supplied O₂, Ce6 produced a plethora of ¹O₂ for enhanced photodynamic therapy, which in turn favored LPO accumulation to synergize ferroptosis. This study presents a promising paradigm for designing nanomedicines to heighten ferroptosis-based synergetic therapeutics through remodeling the intracellular environment.

Pyrazole-sulfonamide scaffold featuring dual-tail strategy as apoptosis inducers in colon cancer

Dual-tail strategy has been successfully utilized in the development of novel carbonic anhydrase IX (CA IX) inhibitors. Herein we adopted this approach in the design and synthesis of a series of novel pyridine sulfonamide-pyrazole hybrid scaffold mimicking dual-tail inhibitors of CA IX. A library of 15 compounds was synthesized and assessed for their potential cytotoxic effects against colorectal cancer cells. Compounds 3, and 11 induced potential cytotoxic effects against the three cancer cell lines (HCT-116, HT-29, and SW-620) with IC₅₀s' of 45.88, 28.27, and 16.57 uM, 25.01, 8.99, and 3.27 µM, respectively. Both compounds induced cellular apoptosis on HCT-116 and SW-620 cells, while compound 3 induced necrosis as well. In addition, both compounds induced cell cycle arrest on G0/G1, and S phases. Also, compound 11 showed potential autophagy induction on both colon cancer cell lines (HCT-116, and HT-29), and a little bit on metastatic type. Both compounds were less cytotoxic than the reference drug on normal epithelial cell. The migration rates of HCT-116 and the metastatic one SW-620 were reduced by both compounds. Finally, molecular docking of compounds 3 and 11 into the active site of CA IX confirmed in vitro inhibitory activity for both compounds.

Differential Activation of NRF2 Signaling Pathway in Renal-Cell Carcinoma Caki Cell Lines

Renal-cell carcinoma (RCC) is a heterogeneous disease consisting of several subtypes based on specific genomic profiles and histological and clinical characteristics. The subtype with the highest prevalence is clear-cell RCC (ccRCC), next is papillary RCC (pRCC), and then chromophobe RCC (chRCC). The ccRCC cell lines are further subdivided into prognostic expression-based subtypes ccA or ccB. This heterogeneity necessitates the development, availability, and utilization of cell line models with the correct disease phenotypic characteristics for RCC research. In this study, we focused on characterizing proteomic differences between the Caki-1 and Caki-2 cell lines that are commonly used in ccRCC research. Both cells are primarily defined as human ccRCC cell lines. Caki-1 cell lines are metastatic, harboring wild-type VHL, whereas Caki-2 are considered as the primary ccRCC cell lines expressing wild-type von Hippel–Lindau protein (pVHL). Here, we performed a comprehensive comparative proteomic analysis of Caki-1 and Caki-2 cells using tandem mass-tag reagents together with liquid chromatography mass spectrometry (LC/MS) for the identification and quantitation of proteins in the two cell lines. Differential regulation of a subset of the proteins identified was validated using orthogonal methods including western blot, q-PCR, and immunofluorescence assays. Integrative bioinformatic analysis identifies the activation/inhibition of specific molecular pathways, upstream regulators, and causal networks that are uniquely regulated and associated with the two cell lines and RCC subtypes, and potentially the disease stage. Altogether, we have identified multiple molecular pathways, including NRF2 signaling, which is the most significantly activated pathway in Caki-2 versus Caki-1 cells. Some of the differentially regulated molecules and signaling pathways could serve as potential diagnostic and prognostic biomarkers and therapeutic targets amongst ccRCC subtypes.

MM/GBSA prediction of relative binding affinities of carbonic anhydrase inhibitors: effect of atomic charges and comparison with Autodock4Zn

Carbonic anhydrase is an attractive drug target for the treatment of many diseases. This paper examines the ability of end-state MM/GBSA methods to rank inhibitors of carbonic anhydrase in terms of their binding affinities. The MM/GBSA binding energies were evaluated using different atomic charge schemes (Mulliken, ESP and NPA) at different levels of theories, including Hartree-Fock, B3LYP-D3(BJ), and M06-2X with the 6-31G(d,p) basis set. For a large test set of 32 diverse inhibitors, the use of B3LYP-D3(BJ) ESP atomic charges yielded the strongest correlation with experiment (R² = 0.77). The use of the recently enhanced Autodock Vina and zinc optimised AD4_Zn force field also predicted ligand binding affinities with moderately strong correlation (R² = 0.64) at significantly lower computational cost. However, the docked poses deviate significantly from crystal structures. Overall, this study demonstrates the applicability of docking to estimate ligand binding affinities for a diverse range of CA inhibitors, and indicates that more theoretically robust MM/GBSA simulations show promise for improving the accuracy of predicted binding affinities, as long as a validated set of parameters is used.

Expression Dynamics of CA IX Epitope in Cancer Cells under Intermittent Hypoxia Correlates with Extracellular pH Drop and Cell Killing by Ureido-Sulfonamide CA IX Inhibitors

Carbonic anhydrase IX (CA IX) is a membrane-bound CA isozyme over-expressed in many hypoxic tumor cells, where it ensures pH homeostasis and has been implicated in tumor survival, metastasis and resistance to chemotherapy and radiotherapy. Given the functional importance of CA IX in tumor biochemistry, we investigated the expression dynamics of CA IX in normoxia, hypoxia and intermittent hypoxia, which are typical conditions experienced by tumor cells in aggressive carcinomas. We correlated the CA IX epitope expression dynamics with extracellular pH acidification and with viability of CA IX-expressing cancer cells upon treatment with CA IX inhibitors (CAIs) in colon HT-29, breast MDA-MB-231 and ovarian SKOV-3 tumor cell models. We observed that the CA IX epitope expressed under hypoxia by these cancer cells is retained in a significant amount upon reoxygenation, probably to preserve their proliferation ability. The extracellular pH drop correlated well with the level of CA IX expression, with the intermittent hypoxic cells showing a similar pH drop to fully hypoxic ones. All cancer cells showed higher sensitivity to CA IX inhibitors (CAIs) under hypoxia as compared to normoxia. The tumor cell sensitivity to CAIs under hypoxia and intermittent hypoxia were similar and higher than in normoxia and appeared to be correlated with the lipophilicity of the CAI.

Cu(ii)-BODIPY photosensitizer for CAIX overexpressed cancer stem cell therapy

Chemoresistance originating from cancer stem cells (CSCs) is a major cause of cancer treatment failure and highlights the need to develop CSC-targeting therapies. Although enormous progress in both photodynamic therapy (PDT) and chemodynamic therapy (CDT) has been made in recent decades, the efficacy of these modalities against CSC remains limited. Here, we report a new generation photosensitizer, CA9-BPS-Cu(ii), a system that combines three subunits within a single molecule, namely a copper catalyst for CDT, a boron dipyrromethene photosensitizer for PDT, and acetazolamide for CSC targeting via carbonic anhydrase-9 (CA9) binding. A therapeutic effect in MDA-MB-231 cells was observed that is ascribed to elevated oxidative stress mediated by a combined CDT/PDT effect, as well as through copper-catalysed glutathione oxidation. The CSC targeting ability of CA9-BPS-Cu(ii) was evident from the enhanced affinity of CA9-BPS-Cu(ii) towards CD133-positive MDA-MB-231 cells where CA9 is overexpressed vs. CD133-negative cells. Moreover, the efficacy of CA9-BPS-Cu(ii) was successfully demonstrated in a xenograft mouse tumour model.

Novel Thiopyrano[2,3-d]thiazole-pyrazole Hybrids as Potential Nonsulfonamide Human Carbonic Anhydrase IX and XII Inhibitors: Design, Synthesis, and Biochemical Studies

In recent years, molecular hybridization strategies have developed into a potent strategy for drug discovery. A series of novel thiopyrano[2,3-d]thiazoles linked to the pyrazole moiety was designed and developed as anticancer agents by a molecular hybridization. Target compounds were synthesized and characterized by spectroscopic tools as well as X-ray crystallography analysis as in the case of thiopyrano[2,3-d]thiazole derivative 5a. The MTT assay was used to demonstrate the in vitro efficacy of compounds 5a-g and 7a-j on MCF-7 and HePG-2. The results showed that some cycloadducts such as bromophenyl-4-thioxo-2-thiazolidinone 3e, 4-methylphenyl derivative of thiopyrano[2,3-d]thiazole 5d, and 6-substituted-thiopyrano[2,3-d]thiazoles 7e-j displayed good to excellent IC₅₀ in the range of 10.08 ± 1.5 to 25.95 ± 2.8 μg/mL against the MCF-7 cell line and from 7.83 ±2.1 to 13.37 ± 1.2 μg/mL against the HePG-2 cell line. To explore the enzymatic tests for isozymes hCAIX and hCAXII, the most promising eight compounds 3e, 5d, and 7e-j with IC₅₀ ranging from 7.83 ± 2.1 to 25.95 ± 2.8 μM were chosen. Compound 7e exhibited an IC₅₀ (0.067 ± 0.003 μM) similar to that of the standard drug AZA against CAIX (0.059 ± 0.003 μM)). For CAXII, the compound 7i had an IC₅₀ equal to 0.123 ± 0.007 μM compared to that of AZA (0.083 ± 0.005 μM). In addition, using flow cytometry, cell cycle analysis and apoptosis studies in HePG-2 were performed for the two potent anticancer and selective carbonic anhydrase agents (7e and 7i). An enzymatic assay of these two compounds against caspase-9 was also examined. Interestingly, the molecular docking studies revealed that compounds 7e and 7i successfully embedded themselves in the active pockets of the CAIX and CAXII enzymes through different interactions. Overall, the novel thiopyrano[2,3-d]thiazole-pyrazole hybrids (7e and 7i) were suggested to be potent and selective inhibitors of CAIX and CAXII.

Novel Insights on CAI-CORM Hybrids: Evaluation of the CO Releasing Properties and Pain-Relieving Activity of Differently Substituted Coumarins for the Treatment of Rheumatoid Arthritis

Pain control is among the most important healthcare services in patients affected by rheumatoid arthritis (RA), but the current therapeutic options (i.e., disease-modifying anti-rheumatic drugs) are limited by the risk of the side effects. In this context, we proposed an innovative approach based on the hybridization between carbonic anhydrase inhibitors (CAIs) and CO releasing molecules (CORMs). The resulting CAI-CORM hybrids were revealed to possess strong anti-inflammatory effects in in vitro models of diseases and to relieve ache symptoms in an in vivo RA rat model. In this work, we have deepened the study of these promising hybrids, designing a library of coumarin-based compounds, also including internal dicobalt hexacarbonyl systems. The results obtained from the CO releasing study, the CA inhibitory activity, and the in vivo pain-relief efficacy evaluation in the RA rat model confirmed the success of this strategy, allowing us to consider CAI-CORM hybrids promising anti-nociceptive agents against arthritis.

Synthesis, Biological and In Silico Studies of Griseofulvin and Usnic Acid Sulfonamide Derivatives as Fungal, Bacterial and Human Carbonic Anhydrase Inhibitors

Carbonic anhydrases (CAs, EC 4.2.1.1) catalyze the essential reaction of CO₂ hydration in all living organisms, being actively involved in the regulation of a plethora of patho-/physiological conditions. A series of griseofulvin and usnic acid sulfonamides were synthesized and tested as possible CA inhibitors. Since β- and γ- classes are expressed in microorganisms in addition to the α- class, showing substantial structural differences to the human isoforms they are also interesting as new antiinfective targets with a different mechanism of action for fighting the emerging problem of extensive drug resistance afflicting most countries worldwide. Griseofulvin and usnic acid sulfonamides were synthesized using methods of organic chemistry. Their inhibitory activity, assessed against the cytosolic human isoforms hCA I and hCA II, the transmembrane hCA IX as well as β- and γ-CAs from different bacterial and fungal strains, was evaluated by a stopped-flow CO₂ hydrase assay. Several of the investigated derivatives showed interesting inhibition activity towards the cytosolic associate isoforms hCA I and hCA II, as well as the three γ-CAs and Malassezia globosa (MgCA) enzyme. Six compounds (1b-1d, 1h, 1i and 1j) were more potent than AAZ against hCA I while five (1d, 1h, 1i, 1j and 4a) showed better activity than AAZ against the hCA II isoform. Moreover, all compounds appeared to be very potent against MgCA with a Ki lower than that of the reference drug. Furthermore, computational procedures were used to investigate the binding mode of this class of compounds within the active site of human CAs.

Design and synthesis of new adamantyl derivatives as promising antiproliferative agents

A series of adamantyl carboxamide derivatives containing sulfonate or sulfonamide moiety were designed as multitargeted inhibitors of ectonucleotide pyrophosphatases/phosphodiesterases (NPPs) and carbonic anhydrases (CAs). The target compounds were investigated for their antiproliferative activity against NCI-60 cancer cell lines panel. Three main series composed of 3- and 4-aminophenol, 4-aminoaniline, and 5-hydroxyindole scaffolds were designed based on a lead compound (A). Compounds 1e (benzenesulfonyl) and 1i (4-fluorobenzenesulfonyl) of 4-aminophenol backbone exhibited the most promising antiproliferative activity. Both compounds exhibited a broad-spectrum and potent inhibition against all the nine tested cancer subtypes. Both compounds showed nanomolar IC50 values over several cancer cell lines that belong to leukemia and colon cancer such as K-562, RPMI-8226, SR, COLO 205, HCT-116, HCT-15, HT29, KM12, and SW-620 cell lines. Compounds 1e and 1i induced apoptosis in K-562 leukemia cells in a dose-dependent manner. Compound 1i showed the highest cytotoxic activity with IC50 value of 200 nM against HT29 cell line. In addition, compounds 1e and 1i were tested against normal breast cells (HME1) and normal skin fibroblast cells (F180) and the results revealed that the compounds are safe toward normal cells compared to cancers cells. Enzymatic assays against NPP1-3 and carbonic anhydrases II, IX, and XII were performed to investigate the possible molecular target(s) of compounds 1e and 1i. Furthermore, a molecular docking study was performed to predict the binding modes of compounds 1e and 1i in the active site of the most sensitive enzymes subtypes.

Exploration of 1,2,3-triazole linked benzenesulfonamide derivatives as isoform selective inhibitors of human carbonic anhydrase

A novel series of 1,2,3-triazole benzenesulfonamide substituted 1,3-dioxoisoindolin-5-carboxylate (7a-l) inhibitors of human α-carbonic anhydrase (hCA) was designed using a tail approach. The design method relies on the hybridization of a benzenesulfonamide moiety with a tail of 1,3-dioxoisoindoline-5-carboxylate and a zinc-binding group on a 1,2,3-triazole scaffold. Among the synthesized analogues, 2‑iodophenyl (7f, K_I of 105.00 nM and S_I of 2.98) and 2‑naphthyl (7h, K_I of 32.11 nM and S_I of 3.48) analogues (over off-target hCA I) and phenyl (7a, K_I of 50.13 nM and S_I of 2.74) and 2,6‑dimethylphenyl (7d, K_I of 50.60 nM and S_I of 3.35) analogues (over off-target hCA II) exhibited a remarkable selectivity for tumor isoforms hCA IX and XII, respectively. Meanwhile, analogue 7a displayed a potent inhibitory effect against the tumor-associated isoform hCA IX (K_I of 18.29 nM) compared with the reference drug acetazolamide (AAZ, K_I of 437.20 nM), and analogue 7h showed higher potency (K_I of 9.22 nM) than AAZ (K_I of 338.90 nM) against another tumor-associated isoform hCA XII. However, adding the lipophilic large naphthyl tail to the 1,3-dioxoisoindolin-5-carboxylate analogues increased both the hCA inhibitory and selective activities against the target isoform, hCA XII. Additionally, these analogues (7a-l) showed IC₅₀ values against the human lung (A549) adenocarcinoma cancer cell line ranging from 129.71 to 352.26 μM. The results of the molecular docking study suggested that the sulfonamide moiety fits snugly into the hCAs active sites and interacts with the Zn²⁺ ion. At the same time, the tail extension engages in various hydrophilic and hydrophobic interactions with the nearby amino acids, which affects the potency and selectivity of the hybrids.

A novel surface functionalization platform to prime extracellular vesicles for targeted therapy and diagnostic imaging

Extracellular vesicles (EVs), nanovesicles released by cells to effectively exchange biological information, are gaining interest as drug delivery system. Yet, analogously to liposomes, they show short blood circulation times and accumulation in the liver and the spleen. For tissue specific delivery, EV surfaces will thus have to be functionalized. We present a novel platform for flexible modification of EVs with target-specific ligands based on the avidin-biotin system. Genetic engineering of donor cells with a glycosylphosphatidylinositol-anchored avidin (GPI-Av) construct allows the isolation of EVs displaying avidin on their surface, functionalized with any biotinylated ligand. For proof of concept, GPI-Av EVs were modified with i) a biotinylated antibody or ii) de novo designed and synthesized biotinylated ligands binding carbonic anhydrase IX (CAIX), a membrane associated enzyme overexpressed in cancer. Functionalized EVs showed specific binding and uptake by CAIX-expressing cells, demonstrating the power of the system to prepare EVs for cell-specific drug delivery.

Design and synthesis of some new benzoylthioureido phenyl derivatives targeting carbonic anhydrase enzymes

The present study aimed to develop potent carbonic anhydrase inhibitors (CAIs). The design of the target compounds was based on modifying the structure of the ureido-based carbonic anhydrase inhibitor SLC-0111. Six series of a substituted benzoylthioureido core were prepared featuring different zinc-binding groups; the conventional sulphamoyl group 4a-d and 12a-c, its bioisosteric carboxylic acid group 5a-d and 13a-c or the ethyl carboxylate group 6a-d and 14a-c as potential prodrugs. All compounds were assessed for their carbonic anhydrase (CA) inhibitory activity against a panel of four physiologically relevant human CA isoforms hCA I and hCA II, and hCA IX, and hCA XII. Compounds 4a, 4b, 4c, 4d, 5d, 12a, and 12c revealed significant inhibitory activity against hCA I that would highlight these compounds as promising drug candidates for the treatment of glaucoma.

Benzenesulfonamides with different rigidity-conferring linkers as carbonic anhydrase inhibitors: an insight into the antiproliferative effect on glioblastoma, pancreatic, and breast cancer cells

Among the chemotypes studied for selective inhibition of tumour-associated carbonic anhydrases (CAs), SLC-0111, a ureido-bearing benzenesulfonamide CA IX inhibitor, displayed promising antiproliferative effects in cancer cells in vitro and in vivo, being in Phase Ib/II clinical development. To explore the structural characteristics required for better discrimination of less conserved regions of the enzyme, we investigate the incorporation of the urea linker into an imidazolidin-2-one cycle, a modification already explored previously for obtaining CA inhibitors. This new library of compounds inhibited potently four different hCAs in the nanomolar range with a different isoform selectivity profile compared to the lead SLC-0111. Several representative CA IX inhibitors were tested for their efficacy to inhibit the proliferation of glioblastoma, pancreatic, and breast cancer cells expressing CA IX, in hypoxic conditions. Unlike previous literature data on SLC-149, a structurally related sulphonamide to compounds investigated here, our data reveal that these derivatives possess promising anti-proliferative effects, comparable to those of SLC-0111.

Indoline-5-Sulfonamides: A Role of the Core in Inhibition of Cancer-Related Carbonic Anhydrases, Antiproliferative Activity and Circumventing of Multidrug Resistance

The overexpression and activity of carbonic anhydrase (CA, EC 4.2.1.1) isoforms CA IX and CA XII promote the accumulation of exceeding protons and acidosis in the extracellular tumor environment. Sulfonamides are effective inhibitors of most families of CAs. In this study, using scaffold-hopping, indoline-5-sulfonamide analogs 4a-u of the CA IX-selective inhibitor 3 were designed and synthesized to evaluate their biological properties. 1-Acylated indoline-5-sulfonamides demonstrated inhibitory activity against tumor-associated CA IX and XII with K_I values up to 132.8 nM and 41.3 nM. Compound 4f, as one of the most potent inhibitors of CA IX and XII, exhibits hypoxic selectivity, suppressing the growth of MCF7 cells at 12.9 µM, and causes partial inhibition of hypoxia-induced CA IX expression in A431 skin cancer cells. 4e and 4f reverse chemoresistance to doxorubicin of K562/4 with overexpression of P-gp.

Carbonic anhydrase IX: A tumor acidification switch in heterogeneity and chemokine regulation

The primary physiological process of respiration produces carbon dioxide (CO₂) that reacts with water molecules which subsequently liberates bicarbonate (HCO-₃) and protons. Carbonic anhydrases (CAs) are the primary catalyst involved in this conversion. More than 16 isoforms of human CAs show organ or subcellular specific activity. Dysregulation of each CA is associated with multiple pathologies. Out of these members, the overexpression of membrane-bound carbonic anhydrase IX (CAIX) is associated explicitly with hypoxic tumors or various solid cancers. CAIX helps tumors deal with higher CO₂ by sequestering it with bicarbonate ions and helping cancer cells to grow in a comparatively hypoxic or acidic environment, thus acting as a pH adaptation switch. CAIX-mediated adaptations in cancer cells include angiogenesis, metabolic alterations, tumor heterogeneity, drug resistance, and regulation of cancer-specific chemokines. This review comprehensively collects and describe the cancer-specific expression mechanism and role of CAIX in cancer growth, progression, heterogeneity, and its structural insight to develop future combinatorial targeted cancer therapies.

Synthesis and anticancer activity of new benzensulfonamides incorporating s-triazines as cyclic linkers for inhibition of carbonic anhydrase IX

Limited presence of hCA IX in normal physiological tissues and their overexpression only in solid hypoxic tumors made this isoform excellent possible target for developing new anticancer agents. We reported designing and synthesis of two novel series of benzenesulfonamides derivatives as hCA IX inhibitors bearing rigid cyclic linkers (1,3,5-dihydrotriazine in series A and 1,3,5-triazine in series B) in replace of traditional linear linkers. Also, novel cyanoethenyl spacer was assembled next to the 1,3,5-triazine linker in series B. Target compounds of series (A) and (B) were screened against four hCA isoforms. Human CA IX efficiently inhibited in series (A) by compound 5a (K_I = 134.8 nM). Meanwhile, in series (B) the most active inhibitor was 12i (K_I = 38.8 nM). US-NCI protocol was followed to evaluate the anticancer activity of target compounds against panel of sixty cancer cell lines. Compound 12d, exposed the best activity towards breast cancer (MDA-MB-468) with GI% = 62%. The most active analogues, 12d and 12i were further screened for in vitro cytotoxic activity under hypoxic condition against breast cancer (MDA-MB-468) (IC₅₀ = 3.99 ± 0.21 and 1.48 ± 0.08 µM, respectively) and leukemia (CCRF-CM) cell line (IC₅₀ = 4.51 ± 0.24 and 9.83 ± 0.52 µM, respectively). In addition, 12d arrested breast cancer MDA-MB-468 cell cycle in G0-G1 and S phases and induced its apoptosis which indicated by increasing the level of cleaved caspases 3 and 9. Molecular docking was performed for selected analogues to understand their biological alterations. This study revealed that insertion of 1,3,5-triazines as cyclic linkers enhanced the significant anticancer and hCA IX inhibition activity of benzenesulfonamides.

New Sulfamethoxazole Derivatives as Selective Carbonic Anhydrase IX and XII Inhibitors: Design, Synthesis, Cytotoxic Activity and Molecular Modeling

In this study new sulphamethoxazole derivatives (S1-S4, S6-S12, and S14-S22) were designed and synthesized and their structures were fully characterized and validated using NMR, mass, and IR spectroscopy, as well as elemental analyses. All new derivatives (S1-S22) were assayed against human carbonic anhydrase (hCAs IX and XII) for their inhibitory activities. hCAs IX and XII were chosen due to the fact that CAIX expression is recognized as a hypoxia marker with a poor prognosis in breast cancer. When compared to Dorzolamide HCl as a standard reference, derivatives S2, S3, S8, S9, and S15 had the most effective inhibition with low IC₅₀ values. The active compounds were further evaluated against hCAs I and II inhibitory activity and compounds S8, S9 and S15 showed the least inhibitory effect compared to the reference standard, acetazolamide, indicating that their effect in normal cells is the lowest. Cell viability tests for the selected compounds were carried out on MCF7 (normoxia and hypoxia) and on the normal breast cell line (MCF10a) with Staurosporine as a standard. The results showed that compound S15 had a highly potent cytotoxic effect. Furthermore, cell cycle analysis results showed that compound S15 triggered cell cycle arrest and apoptosis in G1/S of MCF7 cancer cells. Finally, molecular docking was performed to point out the possible explanation for the vital structural features and key-interactions exerted by our ligands with hCAs IX and XII that might share additional designs and highlight possible leads for a hopeful anticancer agent. Consequently, sulphamethoxazole Derivative S15 could be the potential lead for emerging selective cytotoxic compounds directing h CAs IX and XII.

Novel 2-substituted thioquinazoline-benzenesulfonamide derivatives as carbonic anhydrase inhibitors with potential anticancer activity

A novel series of 2-thioquinazoline-benzenesulfonamide hybrids were designed as carbonic anhydrase (CA) inhibitors. The design approach relies on molecular hybridization between the benzenesulfonamide scaffold as a Zn²⁺ binding group and 2-substituted thioquinazolines as a tail. Assaying the thioquinazoline-benzenesulfonamide conjugates against four different CA isoforms revealed that compounds 12f and 12p are the most potent derivatives. They exhibit K_i  = 0.09 and 0.05 µM on CA II, 0.32 and 0.47 µM on CA IX, and 0.58 and 0.46 µM on CA XII, respectively. In addition, 12p demonstrated high selectivity for CA II over CA I with selectivity index (SI) = 92, and slightly higher specificity for CA II over CA IX and CA XII with SI = 9.40 and 9.20, respectively. The synthesized compounds were screened for their cytotoxic activity at 10 µM concentration and derivatives 12o, 12n, and 12f turned out to be the most potent ones from the synthesized series; they exhibit mean growth inhibition % values of 89.38%, 58.75%, and 54.71%, respectively, while 12p demonstrated moderate activity against the NCI cancer cell lines, with mean growth inhibition % = 29.62%. The analysis of the MCF-7 cell cycle after treatment with 5.0 µM of 12f displayed that it arrests the cell cycle at the G2/M phase. Molecular docking simulation of the thioquinazoline-benzenesulfonamide hybrids in the CA II active site rationalized the potent activity to the settlement of the sulfonamide moiety at the depth of the CA II active site and its stabilization by performing the important interactions with the Zn²⁺ ion as well as with the key amino acids Thr199 and/or Thr200, while the thioquinazoline moiety with different (un)substituted phenyl tails is stabilized by the formation of various hydrogen bonding and hydrophobic interactions with the surrounding amino acids in the binding site.