Discovery of Novel Hydroxyimine-Tethered Benzenesulfonamides as Potential Human Carbonic Anhydrase IX/XII Inhibitors.

To discover novel carbonic anhydrase (CA, EC 4.2.1.1) inhibitors for cancer treatment, a series of 4-{4-[(hydroxyimino)methyl]piperazin-1-yl}benzenesulfonamides were designed and synthesized using SLC-0111 as the lead molecule. The developed novel compounds 27-34 were investigated for the inhibition of human (h) isoforms hCA I, hCA II, hCA IX, and hCA XII. The hCA I was inhibited by compound 29 with a Ki value of 3.0 nM, whereas hCA II was inhibited by compound 32 with a Ki value of 4.4 nM. The tumor-associated hCA IX isoform was inhibited by compound 30 effectively with an Ki value of 43 nM, whereas the activity of another cancer-related isoform, hCA XII, was significantly inhibited by 29 and 31 with a Ki value of 5 nM. Molecular modeling showed that drug molecule 30 participates in significant hydrophobic and hydrogen bond interactions with the active site of the investigated hCAs and binds to zinc through the deprotonated sulfonamide group.

Synthesis and Anticancer Evaluation of Novel Indole Based Arylsulfonylhydrazides against Human Breast Cancer Cells.

A series of novel indole based sulfonohydrazide derivatives (5a-k) containing morpholine heterocyclic ring were synthesized through multistep chemical reactions. The target compounds (5a-k) were prepared by the reaction of substituted phenyl sulfonylhydrazides (2a-k) with morpholine derivative of indole 3-carboxaldehyde. All the target compounds were screened for their anticancer activity in vitro against the estrogen receptor-positive breast cancer line MCF-7 and triple-negative breast cancer cell line, MDA-MB-468. It was found that among all the evaluated compounds, the chemotype 4-chloro-N'-((1-(2-morpholinoethyl)-1H-indol-3-yl)methylene)benzenesulfonohydrazide (5f) showed promising inhibition of both MCF-7 and MDA-MB-468 cancer cells with the respective IC50 values of 13.2 µM and 8.2 µM. Compound 5f was found to be nontoxic against HEK 293 noncancerous cells in the studied concentration range, therefore indicating that such chemotypes inhibit the proliferation of cancerous cells selectively and significantly.

Development of Oxadiazole-Sulfonamide-Based Compounds as Potential Antibacterial Agents.

In this work, substituted 1,2,4-oxadiazoles (OX1-OX27) were screened against five bacterial strains, identified to be OX7 and OX11 as growth inhibitors with minimum inhibitory concentration (MIC) values of 31.25 and 15.75 µg/mL, respectively. The growth inhibitory property of OX7 and OX11 was further validated by disk diffusion, growth curve, and time kill curve assays. Both disrupted biofilm formation with 92-100% reduction examined by the XTT assay were further visualized by scanning electron microscopy analysis. These compounds in combination with ciprofloxacin also exhibit synergy against Escherichia coli cells. With insignificant cytotoxic behavior on HEK293 cells, human red blood cells, and Galleria mellonella larvae, OX11 was tested against 28 multidrug resistant environmental isolates of bacteria and showed inhibition of Kluyvera georgiana and Citrobacter werkmanii strains with 32 and 16 µg/mL MIC values, respectively. The synergistic behavior of OX11 with ampicillin showed many fold reductions in MIC values against K. georgiana and Klebsiella pneumoniae multidrug resistant strains. Further, transmission electron microscopy analysis of OX11-treated E. coli cells showed a significantly damaged cell wall, which resulted in the loss of integrity and cytosolic oozing. OX11 showed significant changes in the secondary structure of human serum albumin (HSA) in the presence of OX11, enhancing HSA stability. Overall, the study provided a suitable core for further synthetic alterations and development as an antibacterial agent.

Advances in Drug Discovery against Neglected Tropical Diseases: Human African and American Trypanosomiasis.

Human African and American trypanosomiasis are the vector-borne parasitic diseases that have killed millions of people early, and many people are yet suffering from these neglected diseases. The causative agents of these infections are parasitic protozoans of the genus Trypanosoma. Current treatment regimens against these endemic diseases have several limitations in terms of safety, efficacy, route of administration, and some of them have lost efficacy due to the emergence of resistance in their respective parasites. In this review, the most promising compounds identified by different strategies of drug development against these neglected diseases including target-based approach, the phenotypic high-throughput screening, the drug repurposing approach and combination therapy are emphasized. The potent heterocyclic compounds currently undergoing pre-clinical or clinical studies have also been assessed to ascertain an effective class of organic compounds having significant therapeutic potential against these tropical diseases. The molecular hybridization of outlined motifs may result in more active compounds and circumvent the development of resistance by specific targets in future.

Deciphering the key heterocyclic scaffolds in targeting microtubules, kinases and carbonic anhydrases for cancer drug development.

Heterocyclic scaffolds are widely utilized for drug design by taking into account the molecular structure of therapeutic targets that are related to a broad spectrum of ailments, including tumors. Such compounds display various covalent and non-covalent interactions with the specific residues of the target proteins while causing their inhibition. There is a substantial number of heterocyclic compounds approved for cancer treatment, and these compounds function by interacting with different therapeutic targets involved in tumorogenesis. In this review, we trace and emphasize the privileged heterocyclic pharmacophores that have immense potency against several essential chemotherapeutic tumor targets: microtubules, kinases and carbonic anhydrases. Potent compounds currently undergoing pre-clinical and clinical studies have also been assessed for ascertaining the effective class of chemical scaffolds that have significant therapeutic potential against multiple malignancies. In addition, we also describe briefly the role of heterocyclic compounds in various chemotherapy regimens. The optimized molecular hybridization of delineated motifs may result in the discovery of more active anticancer therapeutics and circumvent the development of resistance by specific targets in the future.

Design and Development of Small-Molecule Arylaldoxime/5-Nitroimidazole Hybrids as Potent Inhibitors of MARK4: A Promising Approach for Target-Based Cancer Therapy.

Microtubule affinity-regulating kinase 4 (MARK4), a member of the serine/threonine kinase family, is an emerging therapeutic target in anticancer drug discovery paradigm due to its involvement in regulation of microtubule dynamics, cell cycle regulation, and cancer progression. Therefore, to identify the novel chemical architecture for the design and development of novel MARK4 inhibitors with concomitant radical scavenging property, a series of small-molecule arylaldoxime/5-nitroimidazole conjugates were designed and synthesized via multistep chemical reactions following the pharmacophoric hybridization approach. Compound 4h was identified as a promising MARK4 inhibitor with high selectivity toward MARK4 inhibition as compared to the panel of screened 30 kinases pertaining to the serine/threonine family, which was validated by molecular docking and fluorescence binding studies. The comprehensive cell-based examination divulged the promising apoptotic, antiproliferative, and antioxidant potential for the chemotype 4h. The compound 4h was endowed with the K a value of 3.6 × 103 M-1 for human serum albumin, which reflects its remarkable transportation and delivery properties to the target site via blood. The present study impedes that in the future, such compounds may stand as optimized pharmacological lead candidates in drug discovery for targeting cancer via MARK4 inhibition with a remarkable anticancer profile.

Synthesis of metronidazole based thiazolidinone analogs as promising antiamoebic agents.

Metronidazole and its derivatives are widely used for the treatment of amoebiasis. However, metronidazole is considered as the standard drug but it has many side effects. The present study describes the synthesis of a series of metronidazole based thiazolidinone analogs via Knoevenagel condensation of 4-[2-(2-methyl-5-nitro-1H-imidazole-1-yl)ethoxy]benzaldehyde 1 with various thiazolidinone derivatives 2-14 to get the new scaffold (15-27) having better activity and lesser toxicity. Six compounds have shown better efficacy and lesser cytotoxicity than the standard drug metronidazole towards HM1: IMSS strain of Entamoeba histolytica. These compounds may combat the problem of drug resistance and might be effective in identifying potential alternatives for future drug discovery against EhOASS.

Discovery of 4-(2-(dimethylamino)ethoxy)benzohydrazide derivatives as prospective microtubule affinity regulating kinase 4 inhibitors.

Microtubule affinity regulating kinase 4 (MARK4) is a Ser/Thr kinase, considered as a potential drug target for cancer, diabetes and neurodegenerative diseases. Due to its significant role in the development and progression of cancer, different in-house libraries of synthesized small molecules were screened to identify potential MARK4 inhibitors. A small library of hydrazone compounds showed a considerable binding affinity to MARK4. The selected compounds were further scrutinized using an enzyme inhibition assay and finally two hydrazone derivatives (H4 and H19) were selected that show excellent inhibition (nM range). These compounds have a strong binding affinity for MARK4 and moderate binding with human serum albumin. Anticancer studies were performed on MCF-7 and A549 cells, suggesting H4 and H19 selectively inhibit the growth of cancer cells. The IC50 value of compound H4 and H19 was found to be 27.39 µM and 34.37 µM for MCF-7 cells, while for A549 cells it was 45.24 µM and 61.50 µM, respectively. These compounds inhibited the colonogenic potential of cancer cells and induced apoptosis. Overall findings reflect that hydrazones/hydrazone derivatives could be exploited as potential lead molecules for developing effective anticancer therapies via targeting MARK4.

CID-6033590 inhibits p38MAPK pathway and induces S-phase cell cycle arrest and apoptosis in DU145 and PC-3 cells.

Metastatic prostate cancer, with no effective treatment, is among the leading causes of cancer-associated deaths in men. Overexpression of p38αMAPK has been observed in neuroendocrine prostate cancer patients and in both DU145 and PC-3 cell lines and represents a good drug target. Sulfonamide derivatives have shown biological activities against many human diseases, including cancer. CID-6033590, a sulfonylhydrazide compound, screened from PubChem database by molecular docking with p38αMAPK, was evaluated for anti-cancerous activities. CID-6033590 induced toxicity in both DU145 and PC-3 cells in a concentration and time-dependent manner with an IC50 value of 60 µM and 66 µM, respectively. Sub-cytotoxic concentrations of the compound significantly induced S-phase cell cycle arrest, inhibited cyclinA/CDK2 complex and blocked cell proliferation. Further, CID-6033590 downregulated phosphorylation of p38MAPK (P-p38) as well as its downstream targets, Activating transcription factor 2 (ATF-2) and Heat shock protein 27 (Hsp27). The compound increased ROS and decreased mitochondrial membrane potential (Δψm), downregulated Bcl-2 and survivin and cleaved poly ADP ribose polymerase (PARP) and caspase-3, indicating the induction of apoptosis. The evaluaion of the compound on noncancerous, human prostatic epithelial cell line RWPE-1, and healthy murine tissues yielded no significant toxicity. Taken together, we suggest CID-6033590 as a potential candidate for prostate cancer therapy.

Antioxidant and apoptotic effects of Callistemon lanceolatus leaves and their compounds against human cancer cells.

Callistemon lanceolatus (Myrtaceae) has been utilized in folk medicine and its pharmacological properties are widely studied. Phytochemicals are effectively recognized as bases of pharmacologically potent drugs for the development of anticancer therapeutics. The free radical scavenging potential of numerous extracts of C. lanceolatus leaves, Hexane leaf extract (HLE), Chloroform leaf extract (CLE), Ethyl acetate leaf extract (ELE), Methanol leaf extract (MLE), and Aqueous leaf extract (ALE)) were determined by Biochemical assay. We evaluated the anticancer activity of C. lanceolatus leaves extracts against different human cancer cell lines viz liver cancer cells (HepG2), breast cancer cells (MCF7), and normal human embryonic kidney (HEK 293) cell line. The ELE and MLE extracts of C. lanceolatus leaves showed potential antiproliferative effects on HepG2 cells. On the basis of free radical scavenging potential and cytotoxicity studies, ELE and MLE extracts of C. lanceolatus leaves are further evaluated in detail for numerous biological activities. ELE and MLE extracts reduced the cell growth, ROS generation, lowering the potential of cell migration and inhibits the metastatic activity in HepG2 cell lines. ELE and MLE extracts treated HepG2 cells showed down-regulation of STAT3 and up-regulation of p53 and inhibition of cdk2 and cyclin A activity. Phytochemicals analysis have shown that the ELE and MLE possess some anticancer compounds like 4-Fluoro-2-trifluoromethylbenzoic acid, neopentyl ester; fumaric acid, di(pent-4-en-2-yl) ester; 2,3-Dihydro-3,5-dihydroxy-6-methyl-4H-pyran-4-one and 2-Furancarboxaldehyde,5-(hydroxymethyl). Molecular docking results demonstrate that interactions of compounds present in ELE and MLE extracts with the SH2 domain of STAT3, might be responsible for their inhibitory effects. We have further concluded that the ELE and MLE extracts of C. lanceolatus arrests the cells at S and G2/M phase and subsequently induced cell death by regulating the DNA damage in HepG2 cells.

Synthesis, characterization and biological evaluation of tertiary sulfonamide derivatives of pyridyl-indole based heteroaryl chalcone as potential carbonic anhydrase IX inhibitors and anticancer agents.

In the quest for novel effective carbonic anhydrase inhibitors, some sulfonamide derivatives of pyridyl-indole based chalcone were synthesized and screened in vitro for inhibitory activity against human carbonic anhydrase IX isoform. Among all the synthesized compounds (SC2 -SC11), only three compounds SC3, SC7 and SC10 were found to have better binding affinity as shown by molecular docking and fluorescence binding studies. Further, the enzyme inhibition assay and in vitro anti-tumor evaluation against MCF-7 and HepG-2 cell lines revealed that the compounds SC3, SC7 and SC10 inhibited the CA IX selectively, possessed predominant anti-proliferative potential and significantly induced apoptosis in cancerous cells.

Clinical and radiological outcome for Trufit Plug in the treatment of chondral and osteochondral lesions at a minimum of 2 years.

The aim of this study was to evaluate the functional and radiological outcome of TruFit plugs. We retrospectively reviewed 10 patients who underwent treatment for a symptomatic chondral/osteochondral lesion using one or more Trufit Plugs. Full incorporation of the bony portion of the plug occurred in only 3 and partial incorporation in 7 lesions. The remaining portion of these 7 lesions looked cystic on MRI. The significance of this cystic change is not clear. Though all 10 patients showed some improvement on the IKDC scoring system but the amount of the improvement was small.

Synthesis, antiamoebic activity and docking studies of metronidazole-triazole-styryl hybrids.

A series of 22 novel metronidazole-triazole-styryl hybrids were synthesized and evaluated for their in vitro antiamoebic activity against HM1: IMSS strain of Entamoeba histolytica. Some of the hybrids were found to be more active (IC50 = 0.12-0.35 µM) than the reference drug metronidazole (IC50 = 1.79 µM). The most active compounds were found to be non-toxic (up to 50 µM) against the Vero cells showing a good safety profile of these hybrids. The docking and ADMET studies were also conducted to investigate the probable mode of action. Docking studies showed significant binding affinity in the active site of E. histolytica thioredoxin reductase (EhTrR) protein.

Effect of triazole-tryptophan hybrid on the conformation stability of bovine serum albumin.

The effect of a potent antimicrobial compound bearing 1,2,3-triazole core and a tryptophan tail, triazole-tryptophan hybrid (TTH), with bovine serum albumin (BSA) have been explored using various spectroscopic and molecular docking methods. Studies revealed that TTH strongly quenches the intrinsic fluorophore of BSA by a static quenching mechanism. Time-resolved fluorescence spectra further confirmed the involvement of static quenching for TTH-BSA system. The calculated thermodynamic parameters; ΔH, ΔS, and ΔG showed that the binding process was spontaneous, exothermic and entropy driven. Synchronous fluorescence, three-dimensional (3D) fluorescence and circular dichroism data revealed that TTH induces the structural alteration in BSA and enhances its stability. In silico study of TTH-BSA system showed that it binds with BSA at the site I of subdomain IIA. Both the experimental and in silico study showed that the hydrophobic and electrostatic interactions play a major role in TTH-BSA binding.

Design, synthesis and biological evaluation of novel pyridine-thiazolidinone derivatives as anticancer agents: Targeting human carbonic anhydrase IX.

In order to obtain novel Human carbonic anhydrase IX (CAIX) inhibitors, a series of pyridine-thiazolidinone derivatives was synthesized and characterized by various spectroscopic techniques. The binding affinity of the compounds was measured by fluorescence binding studies and enzyme inhibition activity using esterase assay of CAIX. It was observed that compound 8 and 11 significantly inhibit the CAIX activity with the IC50 value, 1.61 µM and 1.84 µM, respectively. The binding-affinity of compound 8 and 11 for CAIX was significantly high with their KD values 11.21 µM and 2.32 µM, respectively. Docking studies revealed that compound 8 and 11 efficiently binds in the active site cavity of CA IX by forming sufficient numbers of H-bonds and van der Waals interactions with active side residues. All the compounds were further screened in vitro for anticancer activity and found that compound 8 and 11 exhibit considerable anticancer activity against MCF-7 and HepG-2 cell lines. All these findings suggest that compound 8 and 11 may be further exploited as a novel pharmacophore model for the development of anticancer agents.

Biological evaluation of p-toluene sulphonylhydrazone as carbonic anhydrase IX inhibitors: An approach to fight hypoxia-induced tumors.

To find potential inhibitors of human carbonic anhydrase IX (CAIX), we have successfully deigned, synthesized and characterized three p-toluene sulphonylhydrazone derivatives (1-3). Molecular docking studies provided the structural basis of CAIX inhibition and a deeper insight into the protein-ligand interactions. p-Toluene sulphonylhydrazone derivatives show a well organized conformational compatibility with the active site of CAIX. The protein-ligand complex was stabilized by several non-covalent interactions offered by residues present in the active site cavity. The actual binding affinity of synthesized compounds with CAIX was experimentally measured by fluorescence and isothermal titration calorimetry (ITC). Results of both fluorescence binding and ITC measurements show the binding affinity of p-Toluene sulphonylhydrazone derivatives to the CAIX in the µM range. CAIX enzyme inhibition assay showed the IC50 values in nM range. Though all the three compounds (1-3) showed a good binding with CAIX, compound 2 showed the best inhibition of CAIX activity. These compounds were non-toxic on normal cell lines (HEK-293) and significantly inhibit the proliferation of hypoxic cancer cells. All compounds induce apoptosis in the hypoxic cancer cells. These compounds may be further exploited as promising therapeutic agents to control the hypoxia-induced tumors.

Understanding the Role and Mechanism of Carbonic Anhydrase V in Obesity and its Therapeutic Implications.

Obesity is a metabolic syndrome leading to several health problems such as hypertension, heart attack, type II diabetes, and even cancer. Carbonic anhydrase VA (CAVA) is a mitochondrial enzyme which is directly associated with the glucose homeostasis and considered as a promising target for obesity and other associated diseases in humans. So far, numerous inhibitors have been designed to inhibit the catalytic activity of CAVA with an assumption for its possible therapeutic uses against type II diabetes and other metabolic diseases. Among these, sulphonamide inhibitors and various non-classical inhibitors are extensively used. The focus of this review is to understand the mechanism and role CAVA in glucose homeostasis to ascertain as a potential drug target of obesity. We have further highlighted different types of inhibitors and their mode of binding and possible consequences with an aim to investigate possible therapeutic used for the treatment of obesity and associated diseases. Along with classical inhibitors, various non-classical inhibitors have proved to be potential inhibitors of CAV which may be employed to combat obesity. Certain phytochemicals are utilized as therapeutic molecules to fight obesity. These phytochemicals have been discussed in detail here.

Inhibitory growth evaluation and apoptosis induction in MCF-7 cancer cells by new 5-aryl-2-butylthio-1,3,4-oxadiazole derivatives.

BACKGROUND: Cancer has become one of the global health issues and it is the life-threatening disease characterized by unrestrained growth of cells. Despite various advances being adopted by chemotherapeutic management, the use of the current anticancer drugs such as Doxorubicin, Asparginase, Methotrexate, Vincristine remains limited due to high toxicity, side effects and developing drug resistance. Apoptosis is a crucial cellular process and improper regulation of apoptotic signaling pathways may lead to cancer formation. Subsequently, the synthesis of effective chemotherapeutic agents that can induce apoptosis in tumor cell has emerged as a significant approach in cancer drug discovery. METHODS: The goal of this work is to develop a potential antitumor agent exerting significant inhibitory effects on cancer cell and low cytotoxicity, for which we focused on the structural features of 1,3,4-oxadiazoles as it a privileged scaffold in modern medicinal chemistry and have the ability to inhibit growth factors, enzymes and kinases potentially involved in the attainment of cellular immortality and carcinogenesis. RESULT: In vitro MTT screening assay showed the compound 5-aminophenyl-2-butylthio-1,3,4-oxadiazole (5e) showing the highest inhibitory effect against MCF-7 cancer cell with IC50 value 10.05 ± 1.08 µM while it is much safer and less toxic on normal cell line (HEK-293). The dose-dependent treatment of MCF-7 cells with 5e resulted in inhibition of cell migration in the wound healing assay. The flow-cytometry analysis showed the cells arrested in G0/G1 phase of the cell cycle. Compound 5e induced apoptosis of MCF-7 cells was characterized using DAPI staining and Annexin V-PE/7-AAD dual binding assay. Reduction of NBT by compound 5e showed a reduced generation of ROS. Western blotting studies showed high activation of apoptotic protein Caspase3 and decrease in expression of anti-apoptotic protein BCL-2. CONCLUSION: Based on the results of in vitro studies, it could be concluded that compound 5e showed a significant inhibitory growth effect on MCF-7 cells and have the potential to be developed as lead molecule and further structural modifications may result in promising new anticancer agents.

Anti-leishmanial and cytotoxic activities of amino acid-triazole hybrids: Synthesis, biological evaluation, molecular docking and in silico physico-chemical properties.

According to WHO, leishmaniasis is a major tropical disease, ranking second after malaria. Significant efforts have been therefore invested into finding potent inhibitors for the treatment. In this work, eighteen novel 1,2,3-triazoles appended with l-amino acid (Phe/Pro/Trp) tail were synthesized via azide-alkyne click chemistry with moderate to good yield, and evaluated for their anti-leishmanial activity against promastigote form of Leishmania donovani (Dd8 strain). Among all, compounds 40, 43, and 53 were identified with promising anti-leishmanial activity with IC50=88.83±2.93, 96.88±12.88 and 94.45±6.51µM respectively and displayed no cytotoxicity towards macrophage cells. Moreover, compound 43 showed highest selectivity index (SI=8.05) among all the tested compounds. Supported by docking studies, the lead inhibitors (40, 43 and 53) showed interactions with key residues in the catalytic site of trypanothione reductase. The results of pharmacokinetic parameters suggest that these selected inhibitors can be carried forward for further structural optimization and pharmacological investigation.

New antiprotozoal agents: Synthesis and biological evaluation of different 4-(7-chloroquinolin-4-yl) piperazin-1-yl)pyrrolidin-2-yl)methanone derivatives.

In an endeavor to develop efficacious antiprotozoal agents 4-(7-chloroquinolin-4-yl) piperazin-1-yl)pyrrolidin-2-yl)methanone derivatives (5-14) were synthesized, characterized and biologically evaluated for antiprotozoal activity. The compounds were screened in vitro against the HM1: IMSS strain of Entamoeba histolytica and NF54 chloroquine-sensitive strain of Plasmodium falciparum. Among the synthesized compounds six exhibited promising antiamoebic activity with IC50 values (0.14-1.26µM) lower than the standard drug metronidazole (IC50 1.80µM). All nine compounds exhibited antimalarial activity (IC50 range: 1.42-19.62µM), while maintaining a favorable safety profile to host red blood cells. All the compounds were less effective as an antimalarial and more toxic (IC50 range: 14.67-81.24µM) than quinine (IC50: 275.6±16.46µM) against the human kidney epithelial cells. None of the compounds exhibited any inhibitory effect on the viability of Anopheles arabiensis mosquito larvae.