Synthesis of bulky-tailed sulfonamides incorporating pyrido[2,3-d][1,2,4]triazolo[4,3-a]pyrimidin-1(5H)-yl) moieties and evaluation of their carbonic anhydrases I, II, IV and IX inhibitory effects

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.

4-(5-Amino-pyrazol-1-yl)benzenesulfonamide derivatives as novel multi-target anti-inflammatory agents endowed with inhibitory activity against COX-2, 5-LOX and carbonic anhydrase: Design, synthesis, and biological assessments

In the current medical era, the single target inhibition paradigm of drug discovery has given way to the multi-target design concept. As the most intricate pathological process, inflammation gives rise to a variety of diseases. There are several drawbacks to the single target anti-inflammatory drugs currently available. Herein, we present the design and synthesis of a novel series of 4-(5-amino-pyrazol-1-yl)benzenesulfonamide derivatives (7a-j) with COX-2, 5-LOX and carbonic anhydrase (CA) inhibitory activities as potential multi-target anti-inflammatory agents. The pharmacophoric 4-(pyrazol-1-yl)benzenesulfonamide moiety in Celecoxib was used as the core scaffold and different substituted phenyl and 2-thienyl tails were grafted via a hydrazone linker to enhance inhibitory activity against hCA IX and XII isoforms, yielding target pyrazoles 7a-j. All reported pyrazoles were evaluated for their inhibitory activity against COX-1, COX-2, and 5-LOX. Pyrazoles 7a, 7b, and 7j showed the best inhibitory activities against the COX-2 isozyme (IC₅₀ = 49, 60 and 60 nM, respectively) and against 5-LOX (IC₅₀ = 2.4, 1.9, and 2.5 μM, respectively) with excellent SI indices (COX-1/COX-2) of 212.24, 208.33, and 158.33, respectively. In addition, the inhibitory activities of pyrazoles 7a-j were evaluated against four different hCA isoforms I, II, IX, and XII. Both transmembrane hCA IX and XII isoforms were potently inhibited by pyrazoles 7a-j with K_I values in the nanomolar range; 13.0-82.1 nM and 5.8-62.0 nM, respectively. Furthermore, pyrazoles 7a and 7b with the highest COX-2 activity and selectivity indices were evaluated in vivo for their analgesic, anti-inflammatory, and ulcerogenic activities. The serum level of the inflammatory mediators was then measured in order to confirm the anti-inflammatory activities of pyrazoles 7a and 7b.

Tail approach synthesis of triazolylthiazolotriazole bearing benzenesulfonamides as carbonic anhydrase inhibitors capable of inducing apoptosis

Inhibition of human carbonic anhydrase (hCA) isoform IX with concurrent induction of apoptosis is a promising approach for targeting cancer in humans. Prompted by the scope, novel benzenesulfonamides containing the 1,2,3-triazolylthiazolotriazole tail were synthesized and screened as inhibitors of hCA isoforms I, II, IV, and IX. The tumor-associated isoform hCA IX was strongly inhibited by the sulfonamides reported here with K_I values ranging from 45 nM to 1.882 μM. Overall, nine compounds showed hCA IX inhibition with K_I  < 250 nM. The glaucoma-associated isoform hCA II was moderately inhibited while the cytosolic isoform hCA I and membrane-bound isoform hCA IV were weakly inhibited by the synthesized sulfonamides. Compound 6Ac (K_I  = 3.6 nM) was found to be an almost three times more potent inhibitor of hCA II as compared to the standard drug acetazolamide (K_I  = 12.1 nM). The selective hCA IX inhibitors were further studied for their apoptotic efficacy in goat ovarian cells and showed better results as compared to the control. A comparative study of previously synthesized compounds and molecular docking study of representative compounds revealed some important generalizations that could prove beneficial in further investigations of isoform-selective hCA inhibitors.

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.

Development of 4-((3-oxo-3-phenylpropyl)amino)benzenesulfonamide derivatives utilizing tail/dual-tail approaches as novel carbonic anhydrase inhibitors

In the current work, we adopted the tail/dual tail approaches to design and synthesize the benzenesulfonamide derivatives 6a-b, 8, 10a-b, 12a-b, 14, and 16 as new SLC-0111 analogs endowed with carbonic anhydrase (CA) inhibitory activity. All the prepared benzenesulfonamide derivatives were tested for their inhibitory action towards hCA isoforms; hCA I, II, IX, and XII. The results revealed their ability to affect the examined isoforms in variable degrees with KI ranges: 49.3-6459 nM for CA I, 5.1-4171 nM for CA II, 9.4-945.1 nM for CA IX, and 5.2-1159 nM for CA XII. As expected, appending a second hydrophilic tail (ethanolamine) in compound 16 significantly enhanced the inhibitory activities towards hCA IX and hCA XII isoforms by about 5-fold in comparison to its single tail analogue 6c (KI = 51.5 and 28.2 nM for 6cvs. 10.2 and 5.2 nM for 16, respectively). Moreover, SAR analysis pointed out the significance of grafting the sulfamoyl functionality at para-position, as well as the incorporation of a bulky hydrophobic tail for CA inhibitory activity. The most potent hCA IX inhibitors (6f and 16) displayed efficient cell growth inhibitory activity against breast cancer cell lines; T-47D (IC50 = 19 and 10.9 μM, respectively) and MCF-7 (IC50 = 7.5 and 5.7 μM, respectively).

A New Reactive Ketenaminal: Synthesis, Coupling Reaction, Tautomeric Study, Docking and Antimicrobial Evaluation of the Products

BACKGROUND

One of the most successful reagents used in the synthesis of the reactive enaminone is DMF-DMA, but it is very expensive with harmful effects on the human health and reacts with special compounds to generate the enaminone such as active methylene centers.

AIM

In this article, we synthesized a new ketenaminal by simple method with inexpensive reagents (through desulfurization in diphenylether).

METHODS

Thus, a novel reactive ketenaminal (enaminone) was synthesized from the desulfurization of 2-((2-(4-chlorophenyl)-2-oxoethyl)thio)-5,7-bis(4-methoxyphenyl)pyrido[2,3-d]pyrimidin- 4(3H)-one with diphenylether. The starting keteneaminal was coupled with diazotized anilines via the known coupling conditions to give a new series of 2-(4-chlorophenyl)-1-(2-(arylhydrazono)-2- oxoethyl)-5,7-bis(4-methoxy-phenyl)pyrido[2,3-d]pyrimidin-4(1H)-ones.

RESULTS

The structures of the new compounds were elucidated based on their IR, 1H-NMR, 13CNMR, and Mass spectra. Moreover, the potency of these compounds as antimicrobial agents has been evaluated. The results showed that some of the products have high activity nearly equal to that of the used standard antibiotic. Additionally, the docking study was done to get the binding mode of the synthesized compounds with the binding site of the DHFR enzyme. The results of molecular docking of the synthesized arylhydrazono compounds are able to fit in DHFR binding site with binding energies ranging from -4.989 to -8.178 Kcal/mol.

CONCLUSION

Our goal was achieved in this context by the synthesis of new ketenaminal from inexpensive reagents, which was utilized in the preparation of bioactive arylhydrazone derivatives.

Synthesis and Biological Evaluation of Coumarin-Linked 4-Anilinomethyl-1,2,3-Triazoles as Potent Inhibitors of Carbonic Anhydrases IX and XIII Involved in Tumorigenesis

A series of coumarin-linked 4-anilinomethyl-1,2,3-triazoles (6a–t) was synthesized via a molecular hybridization approach, through carbon C-6 of the coumarin moiety. The synthesized compounds were evaluated for their inhibition of carbonic anhydrase (CA) isoforms I, II, IX and XIII. CAs IX and XIII were selectively inhibited over the off-target isoforms I and II. The best inhibitory profiles against CA IX were shown by compounds 6a, 6e and 6f (K_i < 50 nM), with compound 6e displaying the best inhibition with a K_i value of 36.3 nM. Compounds 6a, 6b, 6j, 6o and 6q exhibited the best inhibitory profiles against CA XIII (K_i < 100 nM). These compounds can be further explored for the discovery of potent and effective CA IX and CA XIII inhibitors.

Development of novel benzofuran-based SLC-0111 analogs as selective cancer-associated carbonic anhydrase isoform IX inhibitors

In the present study, we describe the design of different series of benzofuran-based derivatives as potential carbonic anhydrase inhibitors (CAIs). The adopted design is based on bioisosteric replacement for the p-fluorophenyl SLC-0111 tail with the lipophilic 2-methylbenzofuran or 5-bromobenzofuran tails to furnish the 2-methylbenzofuran (MBF) sulfonamides (MBFS; 9, 11 and 13) and 5-bromobenzofuran (BBF) sulfonamides (BBFS; 27a-b, 28a-b and 29a-c), respectively. Thereafter, the urea spacer was either elongated to furnish MBFS (17 and 19), and BBFS (30) series, or replaced by a carbamate one to afford MBFS (15). All the designed compounds were synthesized and evaluated for their inhibitory activities against four human (h) CA isoforms: hCA I, II, IX and XII. MBFS (11b and 17) and BBFS (28b, 29a and 30) efficiently inhibited the tumor-related CA IX isoform in the single-digit nanomolar range (K_Is = 8.4, 7.6, 5.5, 7.1 and 1.8 nM, respectively). In particular, MBFS 11b and BBFS 28b exhibited good selectivity toward hCA IX isoform over the main off-target hCA II isoform (S.I. = 26.4 and 58.9, respectively). As a consequence, 11b and 28b were examined for their anticancer and pro-apoptotic activities toward MDA-MB-231 and MCF-7 cancer cell lines.

Novel benzofuran-based sulphonamides as selective carbonic anhydrases IX and XII inhibitors: synthesis and in vitro biological evaluation

Pursuing on our efforts toward searching for efficient hCA IX and hCA XII inhibitors, herein we report the design and synthesis of new sets of benzofuran-based sulphonamides (4a,b, 5a,b, 9a-c, and 10a-d), featuring the zinc anchoring benzenesulfonamide moiety linked to a benzofuran tail via a hydrazine or hydrazide linker. All the target benzofurans were examined for their inhibitory activities toward isoforms hCA I, II, IX, and XII. The target tumour-associated hCA IX and XII isoforms were efficiently inhibited with KIs spanning in ranges 10.0-97.5 and 10.1-71.8 nM, respectively. Interestingly, arylsulfonehydrazones 9 displayed the best selectivity toward hCA IX and XII over hCA I (SIs: 39.4-250.3 and 26.0-149.9, respectively), and over hCA II (SIs: 19.6-57.1 and 13.0-34.2, respectively). Furthermore, the target benzofurans were assessed for their anti-proliferative activity, according to US-NCI protocol, toward a panel of sixty cancer cell lines. Only benzofurans 5b and 10b possessed selective and moderate growth inhibitory activity toward certain cancer cell lines.

Novel 3-substituted coumarins as selective human carbonic anhydrase IX and XII inhibitors: Synthesis, biological and molecular dynamics analysis

In this study, diverse series of coumarin derivatives were developed as potential carbonic anhydrase inhibitors (CAIs). A "tail" approach was adopted by selecting the coumarin motif as a tail that is connected to the ZBG benzenesulfonamide moiety via a hydrazine (4a,b) or hydrazide (5a,b) linker. Thereafter, an aryl sulfone tail was incorporated to afford the dual tailed coumarin-sulfonamide arylsulfonehydrazones (13a-d) and hydrazides (14a,b). Then, the ZBG were removed from compounds 13 and 14 to furnish coumarin arylsulfonehydrazones (11a-d) and hydrazides (12a,b). Coumarin-sulfonamides 4 and 5 emerged as non-selective CAIs as they displayed good inhibitory activities toward all the examined CA isozymes (I, II, IX and XII) in the nanomolar ranges. Interestingly, the "dual-tail" approach (compounds 13 and 14) succeeded in achieving a good activity and selectivity toward CA IX/XII over the physiologically dominant CA I/II. In particular, compounds 13d and 14a were the most selective coumarin-sulfonamide counterparts. Concerning non-sulfonamide coumarin derivatives, coumarins 8 exhibited excellent activity and selectivity profiles against the target hCA IX/XII, whereas, coumarins 11 and 12 reported excellent selectivity profile, but they barely inhibited hCA IX/XII with K_Is spanning in the micromolar ranges. Furthermore, molecular modelling studies were applied to get a deep focus about the feasible affinities and binding interactions for target coumarin-sulfonamides 4, 5, 13 and 14 with the active site for CA II, IX and XII isoforms.

An overview on synthetic and pharmaceutical prospective of pyrido[2,3-d]pyrimidines scaffold

Pyrido[2,3-d]pyrimidine, a fused hetero-bicyclic nucleus containing pyridine and pyrimidine rings has attained the momentary attention in the sphere of multicomponent synthetic protocol and medicinal chemist. Pyrido[2,3-d]pyrimidine derived drugs have manifested diverse pharmacological activities, particularly, anti-inflammatory, cytotoxic, antimicrobial, phosphodiesterase inhibitors and cytokine inhibitors etc. The present review illustrates various modern synthetic strategies adopted, the structure-activity relationship (SAR) aspects and discloses the extensive crucial biological properties (anticancer, anti-infectious, anti-diabetics and CNS agents) of pyrido[2,3-d]pyrimidines.

Synthesis of arylidene hydrazinylpyrido[2,3-d]pyrimidin-4-ones as potent anti-microbial agents

Combination of arylidene hydrazinyl moiety with pyrido[2,3-d]pyrimidin-4-one skeleton in compounds 7‒26 results in the output of unprecedented anti-microbial agents. Arylidene hydrazinyl based on Pyrido[2,3-d]pyrimidin-4-one analoges 7‒26 prepared by the treatment of [2,3-d]pyrimidin-4-ones 6a,b with various aromatic aldehydes. The antimicrobial action for recently synthesized compounds was considered towards gram positive bacterial species (Staphylococcus aurous ATCC- 47077; Bacillus cereus ATCC-12228), gram negative bacterial species (Escherichia coli ATCC-25922; Salmonella typhi ATCC-15566) and Candida albicans ATCC-10231 as fungal strains. The antimicrobial action expanded by expanding the electron donating group in position 2 and 5 for Pyrido[2,3-d]pyrimidin-4-one core. Derivatives 13, 14, 15, 16 and 12; individually appeared hopeful anti-microbial action towards all strains utilized with inhibition zone higher than that of standard reference drug with lowest MIC.

Discovery of Potent Dual-Tailed Benzenesulfonamide Inhibitors of Human Carbonic Anhydrases Implicated in Glaucoma and in Vivo Profiling of Their Intraocular Pressure-Lowering Action

The design of three dual-tailed sulfonamide series 11a-11g, 14a-14h, and 16a-16e as carbonic anhydrase (CA, EC 4.2.1.1) inhibitors are presented. All compounds were evaluated for inhibitory action against pharmacologically relevant human CA isoforms I, II, IV, and VII. Compounds 11a-11g emerged as potent CA inhibitors against the four tested isoforms with a significant selectivity to CA II, which is implicated in glaucoma (K_i in the range 0.36-6.9 nM). X-ray crystallographic analysis of three compounds (11a, 11d, and 11g) bound to CA II showed the validity of the adopted drug design strategy as specific moieties within the ligand structure interacted directly with the hydrophobic and hydrophilic halves of the CA II active site. Compounds 11b-11d and 11g were evaluated for their intraocular pressure-lowering effects in a rabbit model of glaucoma. 11b and 11d showed significant efficacy when compared to the clinically used drug dorzolamide.

Synthesis, biological and molecular dynamics investigations with a series of triazolopyrimidine/triazole-based benzenesulfonamides as novel carbonic anhydrase inhibitors

In the presented work, we report the design and synthesis of different new sets of triazolopyrimidine-based (9a-d) and triazole-based (11a-h, 13a-c, 15a,b, 17a,b and 21a-g) benzenesulfonamides. The newly synthesized sulfonamides were assessed for their inhibitory activities toward four human (h) metalloenzyme carbonic anhydrase (CA, EC 4.2.1.1) isoforms; hCA I, II, IX and XII. The four examined isoforms were inhibited by the prepared sulfonamides (9a-d, 11a-h, 13a-c, 15a,b, 17a,b and 21a-g) in variable degrees with KIs ranges: 94.4-4953.5 nM for hCA I, 6.9-837.6 nM for hCA II, 3.3-85.0 nM for hCA XI, and 4.4-105.0 nM for hCA XII. In particular, sulfonamides 11e, 21a and 21e emerged as single-digit nanomolar hCA IX and hCA XII inhibitors. Interestingly, triazolopyrimidine-based sulfonamide 9d and triazole-based sulfonamide 21e were found to be the most selective hCA IX inhibitors over hCA I (SI = 100.85 and 210.58, respectively) and hCA II (SI = 18.54 and 38.36, respectively). Thereafter, sulfonamides 9d and 21e were docked into the active site of CAs II, IX and XII, then poses showing the best scoring values and favorable binding interactions were subjected to a MM-GBSA based refinement and, limited to CA IX and XII, to a cycle of 100 ns molecular dynamics.

3-Hydrazinoisatin-based benzenesulfonamides as novel carbonic anhydrase inhibitors endowed with anticancer activity: Synthesis, in vitro biological evaluation and in silico insights

Herein we describe the design and synthesis of two series of sulfonamides featuring N-unsubstituted (4a-c) or N-substituted (7a-o) isatin moieties (as tails) connected to benzenesulfonamide moiety via a hydrazine linker. All the prepared sulfonamides (4a-c and 7a-o) showed potent inhibitory activities toward transmembrane tumor-associated human (h) carbonic anhydrase (hCA, EC 4.2.1.1) isoforms, IX and XII with KI range (8.3-65.4 nM) and (11.9-72.9 nM), respectively. Furthermore, six sulfonamides (7e, 7i, 7j, 7m, 7n and 7o) were assessed for their anti-proliferative activity, according to US-NCI protocol, toward a panel of sixty cancer cell lines. Compounds 7j and 7n were the most promising counterparts in this assay displaying broad spectrum anti-proliferative activity toward diverse cell lines. Also, sulfonamide 7n significantly inhibited clonogenicity of HCT-116 cells in a concentration dependent manner in the colony forming assay. Moreover, molecular modeling studies were performed to gain insights for the plausible binding interactions and affinities for the target isatin-based sulfonamides (4a-c and 7a-o) within hCA isoforms II and IX active sites.

Continued exploration and tail approach synthesis of benzenesulfonamides containing triazole and dual triazole moieties as carbonic anhydrase I, II, IV and IX inhibitors

A library of twenty two novel 1,2,3-triazole benzenesulfonamides incorporating thiosemicarbazide, 5(4H)-thione-1,2,4-triazole and variously substituted phenacyl appended 1,2,4-triazole as tail were designed, synthesized and assessed for their efficacy as inhibitors against carbonic anhydrase human (h) isoforms hCA I, II, IV and IX. The physiologically important and off-target cytosolic isoform hCA I was weakly inhibited by most of the newly synthesized sulfonamides while the glaucoma associated isoform hCA II was moderately inhibited with KIs spanning in low nanomolar range (KI = 8.0 nM-0.903 μM). The membrane bound isoform hCA IV, which is known to be involved in glaucoma and retinitis pigmentosa among others, was strongly inhibited by all newly synthesized sulfonamides out of which nine compounds inhibited isoform hCA IV even more effectively as compared to standard drug acetazolamide (AAZ). The membrane bound isoform hCA IX, associated with growth of tumor cells, was moderately inhibited with KIs ranging between 51 nM-3.198 μM. The effect of appending variously substituted tails on heterocyclic moieties over inhibition potential of synthesized sulfonamides is also disclosed which can be of further interest in pharmacological studies for exploring synthesis of isoform selective inhibitors.

Synthesis and biological evaluation of novel 3-(quinolin-4-ylamino)benzenesulfonamidesAQ3 as carbonic anhydrase isoforms I and II inhibitors

Carbonic anhydrases (CAs, EC 4.2.1.1) are crucial metalloenzymes that are involved in diverse bioprocesses. We report the synthesis and biological evaluation of novel series of benzenesulfonamides incorporating un/substituted ethyl quinoline-3-carboxylate moieties. The newly synthesised compounds were in vitro evaluated as inhibitors of the cytosolic human (h) isoforms hCA I and II. Both isoforms hCA I and II were inhibited by the quinolines reported here in variable degrees: hCA I was inhibited with KIs in the range of 0.966-9.091 μM, whereas hCA II in the range of 0.083-3.594 μM. The primary 7-chloro-6-flouro substituted sulphfonamide derivative 6e (KI = 0.083 μM) proved to be the most active quinoline in inhibiting hCA II, whereas, its secondary sulfonamide analog failed to inhibit the hCA II up to 10 μM, confirming the crucial role of the primary sulphfonamide group, as a zinc-binding group for CA inhibitory activity.

Synthesis and anticancer activity of some pyrido[2,3-d]pyrimidine derivatives as apoptosis inducers and cyclin-dependent kinase inhibitors

Aim: Due to emergence of resistance to available anticancer agents, there is a need to search for new cytotoxic agents. Methods: Pyrido[2,3-d]pyrimidines (4-6) and their tricyclic derivatives (7-13) were prepared and screened for their cytotoxicity against breast MCF-7, prostate PC-3 and lung A-549 cancer cell lines as well as normal fibroblasts WI-38. Results: The most active compounds were 6b, 6e and 8d compared with doxorubicin. Moreover, compounds 6b and 8d induced apoptosis in PC-3 and MCF-7, respectively via activation of CASP3 (in PC-3 only), Bax, p53 and down regulation of Bcl2 in addition to CDK4/6 inhibition. Conclusion: Pyrido[2,3-d]pyrimidine represents an important core for discovery of new potent cytotoxic agents acting on the cell cycle via apoptosis induction through either intrinsic or extrinsic pathways.

Synthesis, biological evaluation and in silico studies with 4-benzylidene-2-phenyl-5(4H)-imidazolone-based benzenesulfonamides as novel selective carbonic anhydrase IX inhibitors endowed with anticancer activity

In the presented work, we report the synthesis of a series of 4-benzylidene-2-phenyl-5(4H)-imidazolone-based benzenesulfonamides 7a-fvia the Erlenmeyer-Plöchl reaction. All the prepared imidazolones 7a-f were evaluated as inhibitors of human (h) carbonic anhydrases (CA, EC 4.2.1.1) cytosolic isoforms hCA I and II, as well as transmembrane tumor-associated isoforms hCA IX and XII. All the tested hCA isoforms were inhibited by the prepared imidazolones 7a-f in variable degrees with the following KIs ranges: 673.2-8169 nM for hCA I, 61.2-592.1 nM for hCA II, 23-155.4 nM for hCA XI, and 21.8-179.6 nM for hCA XII. In particular, imidazolones 7a, 7e, and 7f exhibited good selectivity towards the tumor-associated isoforms (CAs IX and XII) over the off-target cytosolic (CAs I and II) with selectivity index (SI) in the range of 6.2-19.4 and 3.3-8, respectively. Moreover, imidazolones 7a-f were screened for their anticancer activity in one dose (10-5 M) assay against a panel of 60 cancer cell lines according to US-NCI protocol. Furthermore, 7a, 7e and 7f were evaluated for their anti-proliferative activity against colorectal cancer HCT-116 and breast cancer MCF-7 cell lines. Furthermore, 7e and 7f were screened for cell cycle disturbance and apoptosis induction in HCT-116 cells. Finally, a molecular docking study was carried out to rationalize the obtained results.

Structure-activity relationship with pyrazoline-based aromatic sulfamates as carbonic anhydrase isoforms I, II, IX and XII inhibitors: Synthesis and biological evaluation

Four new series of aromatic sulfamates were synthesized and investigated for the inhibition of four human (h) isoforms of zinc enzyme carbonic anhydrase (CA, EC 4.2.1.1), hCA I, II, IX, and XII. The reported derivatives, obtained by a sulfamoylation reaction of the corresponding phenolic precursors, bear 3,5-diarylpyrazoline moieties as spacers between the benzenesulfamate fragment which binds the zinc ion from the active site, and the tail of the inhibitor. Pyrazolines are biologically privileged scaffolds, endowed with versatile biological activity, such as an anti-proliferative action. The derivatives were tested for the inhibition of the cytosolic, hCA I and II (off target isoforms) and the trans-membrane, tumor-associated hCA IX and XII enzymes (anticancer drug targets). Generally, hCA I was not effectively inhibited, whereas many low nanomolar inhibitors were evidenced against hCA II (KIs in the range of 0.42-90.1 nM), IX (KIs in the range of 0.72-63.6 nM), and XII (KIs in the range of 0.88-85.2 nM). The best substitution fragments at the pyrazoline ring included for CA II a 4-sulfamic group on the 3-aryl and halogens on the 5-aryl or a methoxy group on the 3-aryl and a 4-sulfamate group on the 5-aryl; for CA IX and CA XII they included the sulfamic group on the 3- or 4-position of the 5-aryl and an electronwithdrawing group on the 4-postion of the 3-aryl ring.

Association between the expression of carbonic anhydrase II and clinicopathological features of hepatocellular carcinoma

The present study aimed to examine the molecular marker associated with the therapy and prognosis of hepatocellular carcinoma (HCC), and further investigate the association between its expression and the clinicopathological features of HCC. To select the core genes closely associated with HCC, differentially expressed genes (DEGs) were analyzed and screened from Gene Expression Omnibus datasets (GSE 36376) using a bioinformatics approach. Tumor and adjacent tissues were collected form 112 patients of HCC who were treated by radical resection. The expression levels of carbonic anhydrase II (CA2) in the tumor and adjacent tissues were determined using reverse transcription-quantitative polymerase chain reaction analysis and immunohistochemistry. The χ² test was applied for observing the association between the expression of CA2 and clinicopathological features of patients with HCC. The effects of the expression of CA2 on the patients' overall survival (OS) and disease-free survival (DFS) were examined via Kaplan-Meier analysis. A total of 83 DEGs were screened and analyzed using gene network analysis, among which CA2 had direct interactions with more than one disease gene of HCC. The results of immunohistochemistry showed that CA2 was expressed at a lower level in the tumor tissues compared with the adjacent tissues (t=3.012, P=0.010). Single factor analysis revealed that the mRNA expression of CA2 was able to predict the recurrence of HCC, and was significantly associated with α-fetoprotein (AFP), microvascular invasion, tumor-node-metastasis (TNM) staging, and recurrence (P<0.05). The expression levels of AFP, CA2 and TNM staging were confirmed to be independent prognostic factors of HCC (P<0.05). Kaplan-Meier analysis demonstrated that the group with a high expression of CA2 showed increased DFS and OS, compared with the low expression group (P<0.05). These findings indicated that elevated CA2 increased DFS and OS of HCC, which suggested that CA2 may be a potential target for HCC therapy.

Novel Diamide-Based Benzenesulfonamides as Selective Carbonic Anhydrase IX Inhibitors Endowed with Antitumor Activity: Synthesis, Biological Evaluation and In Silico Insights

In this work, we present the synthesis and biological evaluation of novel series of diamide-based benzenesulfonamides 5a–h as inhibitors of the metalloenzyme carbonic anhydrase (CA, EC 4.2.1.1) isoforms hCA I, II, IX and XII. The target tumor-associated isoforms hCA IX and XII were undeniably the most affected ones (K_Is: 8.3–123.3 and 9.8–134.5 nM, respectively). Notably, diamides 5a and 5h stood out as a single-digit nanomolar hCA IX inhibitors (K_Is = 8.8 and 8.3 nM). The SAR outcomes highlighted that bioisosteric replacement of the benzylidene moiety, compounds 5a–g, with the hetero 2-furylidene moiety, compound 5h, achieved the best IX/I and IX/II selectivity herein reported with SIs of 985 and 13.8, respectively. Molecular docking simulations of the prepared diamides within CA IX active site revealed the ability of 5h to establish an additional H-bond between the heterocyclic oxygen and HE/Gln67. Moreover, benzenesulfonamides 5a, 5b and 5h were evaluated for their antitumor activity against renal cancer UO-31 cell line. Compound 5h was the most potent derivative with about 1.5-fold more enhanced activity (IC₅₀ = 4.89 ± 0.22 μM) than the reference drug Staurosporine (IC₅₀ = 7.25 ± 0.43 μM). Moreover, 5a and 5h were able to induce apoptosis in UO-31 cells as evidenced by the significant increase in the percent of annexinV-FITC positive apoptotic cells by 22.5- and 26.5-folds, respectively.

Novel synthesized SLC-0111 thiazole and thiadiazole analogues: Determination of their carbonic anhydrase inhibitory activity and molecular modeling studies

In the presented work, we report the design and synthesis of novel SLC-0111 thiazole and thiadiazole analogues (11a-d, 12a-d, 16a-c and 17a-d). A bioisosteric replacement approach was adopted to replace the 4-fluorophenyl tail of SLC-0111 with thiazole and thiadiazole ones, which were thereafter extended with lipophilic un/substituted phenyl moieties. All the newly synthesized SLC-0111 analogues were evaluated in vitro for their inhibitory activity towards a panel of the metalloenzyme carbonic anhydrase (CA, EC 4.2.1.1) isoforms (hCA I, II, IX and XII), using a stopped-flow CO₂ hydrase assay. All the examined isoforms were inhibited by the primary sulfonamide derivatives (11a-d and 12a-d) in variable degrees with the following K_I ranges: 162.6-7136 nM for hCA I, 9.0-833.6 nM for hCA II, 7.9-153.0 nM for hCA IX, and 9.4-94.0 nM for hCA XII. In particular, compounds 12b and 12d displayed 5.5-fold more potent inhibitory activity (K_Is = 8.3 and 7.9 nM, respectively) than SLC-0111 (K_I = 45 nM) towards hCA IX. Molecular docking study was carried out for 12d within the hCA IX (PDB 3IAI) active site, to justify its inhibitory activity.

SLC-0111 enaminone analogs, 3/4-(3-aryl-3-oxopropenyl) aminobenzenesulfonamides, as novel selective subnanomolar inhibitors of the tumor-associated carbonic anhydrase isoform IX

SLC-0111, an ureido substituted benzenesulfonamide, is a selective carbonic anhydrase (CA, EC 4.2.1.1) IX inhibitor that is currently in Phase I/II clinical trials for the treatment of advanced hypoxic tumors complicated with metastases. Herein we report the synthesis of two series of 3/4-(3-aryl-3-oxopropenyl) aminobenzenesulfonamides 5a-i and 6a-j as SLC-0111 enaminone congeners. The prepared enaminones were in vitro investigated as inhibitors of the metalloenzyme carbonic anhydrase (CA, EC 4.2.1.1) isoforms hCA I, II, IV and IX, using a stopped-flow CO₂ hydrase assay. All these isoforms were inhibited by the enaminones reported here in variable degrees. The target tumor-associated isoform hCA IX was undeniably the most affected one (K_Is: 0.21-7.1 nM), with 6- to 21-fold enhanced activity than SLC-0111 (K_I = 45 nM). All the prepared enaminones displayed interesting selectivity towards hCA IX over hCA I (SI: 32 - >35714), hCA II (SI: 2 - 1689) and hCA IV (SI: 11 - >45454). Of particular interest, bioisosteric replacement of phenyl tail with the bulkier 2-naphthyl tail, sulfonamide 6h, achieved the higher II/IX selectivity herein reported with SI of 1689.

Enhancement of the tail hydrophobic interactions within the carbonic anhydrase IX active site via structural extension: Design and synthesis of novel N-substituted isatins-SLC-0111 hybrids as carbonic anhydrase inhibitors and antitumor agents

Herein we report the design and synthesis of novel N-substituted isatins-SLC-0111 hybrids (6a-f and 9a-l). A structural extension approach was adopted via N-alkylation and N-benzylation of isatin moiety to enhance the tail hydrophobic interactions within the carbonic anhydrase (CA) IX active site. Thereafter, a hybrid pharmacophore approach was utilized via merging the pharmacophoric elements of isatin and SLC-0111 in a single chemical framework. As planned, a substantial improvement of inhibitory profile of the target hybrids (K_Is: 4.7-86.1 nM) towards hCA IX in comparison to N-unsubstituted leads IVa-c (K_Is: 192-239 nM), was achieved. Molecular docking of the designed hybrids in CA IX active site unveiled, as planned, the ability of N-alkylated and N-benzylated isatin moieties to accommodate in a wide hydrophobic pocket formed by T73, P75, P76, L91, L123 and A128, establishing strong van der Waals interactions. Hybrid 6c displayed good anti-proliferative activity under hypoxic conditions towards breast cancer MDA-MB-231 and MCF-7 cell lines (IC₅₀ = 7.43 ± 0.28 and 12.90 ± 0.34 μM, respectively). Also, 6c disrupted the MDA-MB-231 cell cycle via alteration of the Sub-G₁ phase and arrest of G₂-M stage. Additionally, 6c displayed significant increase in the percent of annexinV-FITC positive apoptotic cells from 1.03 to 18.54%. Furthermore, 6c displayed potent VEGFR-2 inhibitory activity (IC₅₀ = 260.64 nM). Collectively, these data suggest 6c as a promising lead molecule for the development of effective anticancer agents.

Novel hydrazido benzenesulfonamides-isatin conjugates: Synthesis, carbonic anhydrase inhibitory activity and molecular modeling studies

As a part of our ongoing efforts towards developing novel carbonic anhydrase inhibitors based on the isatin moiety, herein we report the synthesis and biological evaluation of novel sulfonamides (5a-h, 10a-g and 11a-c) incorporating substituted 2-indolinone moiety (as tail) linked to benzenesulfonamide (as zinc anchoring moiety) through a hydrazide linker. The synthesized sulfonamides were evaluated in vitro for their inhibitory activity against the following human (h) carbonic anhydrase (hCA, EC 4.2.1.1) isoforms, hCA I, II, IX and XII. All these isoforms were inhibited by the sulfonamides reported here in variable degrees. hCA I was inhibited with KIs in the range of 671.8: 3549.5 nM, hCA II in the range of 36.8: 892.4 nM; hCA IX in the range of 8.9: 264.5 nM, whereas hCA XII in the range of 9.0: 78.1 nM. In particular, compound 10b emerged as a single-digit nanomolar hCA IX and XII inhibitor (8.9 and 9.2 nM, respectively). Molecular docking studies carried out for compound 10b within the hCA II, IX and XII active sites allowed us to rationalize the obtained inhibition results.

Synthesis, biological evaluation and computational studies of novel iminothiazolidinone benzenesulfonamides as potent carbonic anhydrase II and IX inhibitors

A series of iminothiazolidinone-sulfonamide hybrids (2a-k) was synthesized by heterocyclization of sulfanilamide thioureas with methyl bromoacetate and characterized by spectroscopic techniques, mass and elemental analysis. The synthesized derivatives were screened against four relevant human (h) isoforms of carbonic anydrases (CAs, EC 4.2.1.1) I, II, IV and IX. These enzymes are involved in a variety of diseases, including glaucoma, retinitis pigmentosa, epilepsy, arthritis, and tumors. Derivatives 2a-2k exhibited the best inhibitory activity against the cytosolyc hCA II (KIs are reaching the sub-nanomolar range, 0.41-37.8 nM) and against the tumor-associated isoform hCA IX (KIs are spanning between 24.3 and 368.3 nM). The binding mode of the reported iminothiazolidinone benzenesulfonamides within hCA II and IX catalytic clefts was investigated by docking studies.

An improved synthesis of pyrido[2,3-d]pyrimidin-4(1H)-ones and their antimicrobial activity

The screening of a small chemical library showed 2-thioxodihydropyrido[2,3-d]pyrimidine 10a had broad spectrum antibacterial activity (MIC 0.49–3.9 μg mL⁻¹), and reasonable antifungal activity (MIC 31.25 μg mL⁻¹).