Synthesis, anti-cancer screening and tyrosyl-DNA phosphodiesterase 1 (Tdp1) inhibition activity of novel piperidinyl sulfamides

Design, synthesis and insecticidal activity of benzenesulfonamide derivatives containing various alkynyl, alkenyl and cyclopropyl groups in para position

Celangulin V is a natural β-dihydrofuran sesquiterpene polyester with anti Mythimna separate activity and unique mechanism of action. Further study showed that its target was the H subunit of V-ATPase in the midgut of M. separate. Thus, combined with the previous work, thirty-two benzene sulfonamide derivatives were systematically synthesised to discover efficient and low-budget insecticidal candidates for the H subunit of V-ATPase. Screening results showed that compounds C2, C4, C5, C6 and C8 could significantly cause death of tested third-instar larvae of M. separate, and provided the corresponding LC50 values of 0.844, 0.953, 0.705, 0.599 and 0.887 mg/mL, which were extremely better than Celangulin V (LC50 = 11.5 mg/mL). The docking results indicated that this novel framework might target H subunit of V-ATPase. Given these excellent bioactivity results, this kind of sulfonamide framework could provide a suitable point for exploring highly efficient insecticidal agents.

A Dual-Sensor-Based Screening System for In Vitro Selection of TDP1 Inhibitors

DNA sensors can be used as robust tools for high-throughput drug screening of small molecules with the potential to inhibit specific enzymes. As enzymes work in complex biological pathways, it is important to screen for both desired and undesired inhibitory effects. We here report a screening system utilizing specific sensors for tyrosyl-DNA phosphodiesterase 1 (TDP1) and topoisomerase 1 (TOP1) activity to screen in vitro for drugs inhibiting TDP1 without affecting TOP1. As the main function of TDP1 is repair of TOP1 cleavage-induced DNA damage, inhibition of TOP1 cleavage could thus reduce the biological effect of the TDP1 drugs. We identified three new drug candidates of the 1,5-naphthyridine and 1,2,3,4-tetrahydroquinolinylphosphine sulfide families. All three TDP1 inhibitors had no effect on TOP1 activity and acted synergistically with the TOP1 poison SN-38 to increase the amount of TOP1 cleavage-induced DNA damage. Further, they promoted cell death even with low dose SN-38, thereby establishing two new classes of TDP1 inhibitors with clinical potential. Thus, we here report a dual-sensor screening approach for in vitro selection of TDP1 drugs and three new TDP1 drug candidates that act synergistically with TOP1 poisons.

Investigation on the Anticancer Activity of Symmetric and Unsymmetric Cyclic Sulfamides

The sulfamide functional group has been extensively employed in organic synthesis to discover probes and drugs in various applications such as cancer, human immunodeficiency virus (HIV), virus, and diabetes. Herein, we describe the synthesis of 7-membered symmetric and unsymmetric sulfamide compounds and their biological evaluation through the National Cancer Institute (NCI) panel of 60 human tumor cell lines (NCI-60) and the mechanism of action study. The results of a study from the NCI-60 cell line exhibited that many synthesized cyclic sulfamide compounds inhibited breast cancer (MDA-MB-468). The mechanism of action study of a representative compound 18 showed the inhibition of proliferation and apoptosis in A549 lung cancer cells.

Novel Inhibitors of DNA Repair Enzyme TDP1 Combining Monoterpenoid and Adamantane Fragments

BACKGROUND AND OBJECTIVE

The DNA repair enzyme tyrosyl-DNA-phosphodiesterase 1 (TDP1) is a current inhibition target to improve the efficacy of cancer chemotherapy. Previous studies showed that compounds combining adamantane and monoterpenoid fragments are active against TDP1 enzyme. This investigation is focused on the synthesis of monoterpenoid derived esters of 1-adamantane carboxylic acid as TDP1 inhibitors.

METHODS

New esters were synthesized by the interaction between 1-adamantane carboxylic acid chloride and monoterpenoid alcohols. The esters were tested against TDP1 and its binding to the enzyme was modeling.

RESULTS

13 Novel ester-based TDP1 inhibitors were synthesized with yields of 21-94%; of these, nine esters had not been previously described. A number of the esters were found to inhibit TDP1, with IC50 values ranging from 0.86-4.08 µM. Molecular modelling against the TDP1 crystal structure showed a good fit of the active esters in the catalytic pocket, explaining their potency. A non-toxic dose of ester, containing a 3,7- dimethyloctanol fragment, was found to enhance the cytotoxic effect of topotecan, a clinically used anti-cancer drug, against the human lung adenocarcinoma cell line A549.

CONCLUSION

The esters synthesized were found to be active against TDP1 in the lower micromolar concentration range, with these findings being corroborated by molecular modeling. Simultaneous action of the ester synthesized from 3,7-dimethyloctanol-1 and topotecan revealed a synergistic effect.

Targeting Tyrosyl-DNA phosphodiesterase I to enhance toxicity of phosphodiester linked DNA-adducts

Our genomic DNA is under constant assault from endogenous and exogenous sources, which needs to be resolved to maintain cellular homeostasis. The eukaryotic DNA repair enzyme Tyrosyl-DNA phosphodiesterase I (Tdp1) catalyzes the hydrolysis of phosphodiester bonds that covalently link adducts to DNA-ends. Tdp1 utilizes two catalytic histidines to resolve a growing list of DNA-adducts. These DNA-adducts can be divided into two groups: small adducts, including oxidized nucleotides, RNA, and non-canonical nucleoside analogs, and large adducts, such as (drug-stabilized) topoisomerase- DNA covalent complexes or failed Schiff base reactions as occur between PARP1 and DNA. Many Tdp1 substrates are generated by chemotherapeutics linking Tdp1 to cancer drug resistance, making a compelling argument to develop small molecules that target Tdp1 as potential novel therapeutic agents. Tdp1's unique catalytic cycle, which is centered on the formation of Tdp1-DNA covalent reaction intermediate, allows for two principally different targeting strategies: (1) catalytic inhibition of Tdp1 catalysis to prevent Tdp1-mediated repair of DNA-adducts that enhances the effectivity of chemotherapeutics; and (2) poisoning of Tdp1 by stabilization of the Tdp1- DNA covalent reaction intermediate, which would increase the half-life of a potentially toxic DNA-adduct by preventing its resolution, analogous to topoisomerase targeted poisons such as topotecan or etoposide. The catalytic Tdp1 mutant that forms the molecular basis of the autosomal recessive neurodegenerative disease spinocerebellar ataxia with axonal neuropathy best illustrates this concept; however, no small molecules have been reported for this strategy. Herein, we concisely discuss the development of Tdp1 catalytic inhibitors and their results.

The Development of Tyrosyl-DNA Phosphodiesterase 1 Inhibitors. Combination of Monoterpene and Adamantine Moieties via Amide or Thioamide Bridges

Eleven amide and thioamide derivatives with monoterpene and adamantine substituents were synthesised. They were tested for their activity against the tyrosyl-DNA phosphodiesterase 1 DNA (Tdp1) repair enzyme with the most potent compound 47a, having an IC50 value of 0.64 M. When tested in the A-549 lung adenocarcinoma cell line, no or very limited cytotoxic effect was observed for the ligands. However, in conjunction with topotecan, a well-established Topoisomerase 1 (Top1) poison in clinical use against cancer, derivative 46a was very cytotoxic at 5 M concentration, displaying strong synergism. This effect was only seen for 46a (IC50—3.3 M) albeit some other ligands had better IC50 values. Molecular modelling into the catalytic site of Tdp1 predicted plausible binding mode of 46a, effectively blocking access to the catalytic site.

Dual DNA topoisomerase 1 and tyrosyl-DNA phosphodiesterase 1 inhibition for improved anticancer activity

Tyrosyl-DNA phosphodiesterase 1 (Tdp1) is a DNA repair enzyme that catalyzes the hydrolysis of the phosphodiester bond in the DNA-topoisomerase 1 (Top1) covalent complex and repairs some other 3'-end DNA adducts. Currently, Tdp1 functions as an important target in cancer drug design owing to its ability to break down various DNA adducts induced by chemotherapeutics. Tdp1 inhibitors may sensitize tumor cells to the action of Top1 poisons, thereby potentiating their effects. This mini-review summarizes findings from studies reporting the combined inhibition of Top1 and Tdp1. Two different approaches have been considered for developing such drug precursors.

The Development of Tyrosyl-DNA Phosphodyesterase 1 (TDP1) Inhibitors Based on the Amines Combining Aromatic/Heteroaromatic and Monoterpenoid Moieties

Background:

Inhibition of the DNA repair enzyme, tyrosyl-DNA phosphodiesterase 1 (TDP1), may increase the efficacy of cancer drugs that cause damage to tumor cell DNA. Among the known TDP1 inhibitors, there are compounds containing moieties of natural substances, e.g., monoterpenoids. In this work, we synthesized several compounds containing aromatic/ heteroaromatic amines and monoterpenoid groups and assessed their TDP1 inhibition potential.

Methods:

Structures of all the synthesized compounds were confirmed by 1H and 13C NMR as well as HRMS. The TDP1 inhibitory activity of the amines was determined by real-time fluorescence oligonucleotide biosensor.

Results:

The synthesized secondary amines had TDP1 inhibitory activity IC50 in the range of 0.79-9.2 µM. The highest activity was found for (–)-myrtenal derivatives containing p-bromoaniline or m-(trifluoromethyl)aniline residue.

Conclusion:

We synthesized 22 secondary amines; of these, 17 amines are novel chemical structures. Many of the amines inhibit TDP1 activity in the low micromolar range. Therefore, these compounds are promising for further study of their antiproliferative activity in conjunction with DNA damaging drugs.

Design, Synthesis, Anti-Proliferative, Anti-microbial, Anti-Angiogenic Activity and In Silico Analysis of Novel Hydrazone Derivatives

BACKGROUND

Cancer is the second leading cause of death globally. Hydrazone and hydrazone derivatives have high activity, and for this reason, these compound are greatly used by researchers to synthesize new anti-cancer drug. The aim of this research work is to synthesize novel anticancer agents.

METHODS

New hydrazone derivatives were synthesized via a reaction between 3-formylphenyl methyl carbonate and benzhydrazide, 4-methylbenzoic hydrazide, 4-tert-butylbenzoic hydrazide, 4-nitrobenzoic hydrazide and 3- methoxybenzoic hydrazide, and were successfully characterized using elemental analysis, ¹H-NMR, ¹³C-NMR, FT-IR and LC-MS techniques. The synthesized compounds were evaluated for their antimicrobial (some grampositive and -negative bacteria, filamentous fungi and yeasts), anti-proliferative (T47D and HCC1428-breast cancer cells) and anti-angiogenic (HUVEC-endothelial cells) activities. The anti-proliferative activities of the hydrazone compounds R1-R5 were studied on these cell lines by MTT assay. The anti-angiogenic potential of the compounds was determined by the endothelial tube formation assay. To identify structural features related to the anti-proliferative activity of these compounds, 2D-QSAR was performed.

RESULT

The results indicated that compound R3 exhibited strong anti-angiogenic and anti-proliferative activity on breast cancer cell lines and healthy cell lines. Also, this compound; possessing a tertiary butyl moiety on the hydrazine, exhibited the highest inhibitory effect against all tested microorganisms; in particular, it inhibited Candida albicans at a lower concentration than ketoconazole. Among the investigated compounds, those bearing methyl, tertiary butyl (compound R2, R3) and methoxy (compound R5) moiety were found to be more successful anticandidal derivatives than standard antifungal antibiotics. The QSAR analysis suggested that the tumor specificity of the hydrazone correlated with their molecular weight, lipophilicity, molar refractivity, water solubility, DipolHybrid:(MOPAC) and ExchangeEnergy:(MOPAC). Absorption, Distribution, Metabolism and Elimination (ADME) analysis of the hydrazone compounds showed that they have favorable pharmacokinetic and drug-likeness properties. The ADME results clarify that R3 is the best compound in terms of pharmacokinetic properties. In contrast to other compounds; target prediction analysis of the compound R3 showed inhibitory activity on estrogen-related receptor alpha transcription factor (ESRRA). The target prediction analysis was supported by molinspiration bioactivity score.

CONCLUSION

The R3 compound is considered to be an important candidate for future studies with its suitability for the Lipinski's rule of five for drug-likeness, and effective in vitro and in silico results.

Novel tyrosyl-DNA phosphodiesterase 1 inhibitors enhance the therapeutic impact of topoteсan on in vivo tumor models

The druggability of the tyrosyl-DNA phosphodiesterase 1 (Tdp1) enzyme was investigated in conjunction with topoisomerase 1 inhibition. A novel class of thiazole, aminothiazole and hydrazonothiazole usnic acid derivatives was synthesized and evaluated as Tdp1 inhibitors and their ability to sensitize tumors to topotecan, a topoisomerase inhibitor in clinical use. Of all the compounds tested, four hydrazinothiazole derivatives, 20c, 20d, 20h and 20i, inhibited the enzyme in the nanomolar range. The activity of the compounds was verified by affinity experiments as well as supported by molecular modelling. The most effective Tdp1 inhibitor, 20d, was ton-toxic and increased the effect of topotecan both in vitro and in vivo in the Lewis lung carcinoma model. Furthermore, 20d showed significant increase in the antitumor and antimetastatic effect of topotecan in mice. The results presented here justify compound 20d to be considered as a drug lead for antitumor therapy.

Synthesis, Spectroscopic Characterization, and In Vitro Antibacterial Evaluation of Novel Functionalized Sulfamidocarbonyloxyphosphonates

Several new sulfamidocarbonyloxyphosphonates were prepared in two steps, namely carbamoylation and sulfamoylation, by using chlorosulfonyl isocyanate (CSI), α-hydroxyphosphonates, and various amino derivatives and related (primary or secondary amines, β-amino esters, and oxazolidin-2-ones). All structures were confirmed by ¹H, ¹³C, and ³¹P NMR spectroscopy, IR spectroscopy, and mass spectroscopy, as well as elemental analysis. Eight compounds were evaluated for their in vitro antibacterial activity against four reference bacteria including Gram-positive Staphylococcus aureus (ATCC 25923), and Gram-negative Escherichia coli (ATCC 25922), Klebsiella pneumonia (ATCC 700603), Pseudomonas aeruginosa (ATCC 27853), in addition to three clinical strains of each studied bacterial species. Compounds 1a⁻7a and 1b showed significant antibacterial activity compared to sulfamethoxazole/trimethoprim, the reference drug used in this study.