Synthesis and biological evaluation of pyrrolo[2,3- b ]pyridine analogues as antiproliferative agents and their interaction with calf thymus DNA

Identification of hydroxyphenyl cyanovinyl thiazoles as new structural scaffold of potential antibacterial agents

Unique hydroxyphenyl cyanovinyl thiazoles (HCTs) as new structural scaffolds of potential antibacterial agents were developed to overcome global increasingly serious drug resistance. Some synthesized HCTs could suppress the growth of the tested strains, especially, benzothiophenyl HCT 5c exhibited superior anti-Escherichia coli activity with a lower MIC of 0.5 μg/mL to norfloxacin (MIC = 1 μg/mL). The active benzothiophenyl HCT 5c displayed no obvious hemolysis, low cytotoxicity and a much lower trend for the development of drug-resistance than norfloxacin. Further exploration revealed that benzothiophenyl HCT 5c could intercalate to DNA to form a DNA-5c complex, which disturbed the biological functions to facilitate bacterial death. ADME analysis indicated that compound 5c possessed favorable druggability and promising pharmacokinetic properties. This work provided an insight into further developing hydroxyphenyl cyanovinyl thiazoles as new structural scaffold of promising antibacterial candidates.

A Unique Hybridization Route to Access Hydrazylnaphthalimidols as Novel Structural Scaffolds of Multitargeting Broad-Spectrum Antifungal Candidates

This study developed a class of novel structural antifungal hydrazylnaphthalimidols (HNs) with multitargeting broad-spectrum potential via multicomponent hybridization to confront increasingly severe fungal invasion. Some prepared HNs exhibited considerable antifungal potency; especially nitrofuryl HN 4a (MIC = 0.001 mM) exhibited a potent antifungal activity against Candida albicans, which is 13-fold higher than that of fluconazole. Furthermore, nitrofuryl HN 4a displayed low cytotoxicity, hemolysis and resistance, as well as a rapid fungicidal efficacy. Preliminary mechanistic investigations revealed that nitrofuryl HN 4a could inhibit lactate dehydrogenase to decrease metabolic activity and promote the accumulation of reactive oxygen species, leading to oxidative stress. Moreover, nitrofuryl HN 4a did not exhibit membrane-targeting ability; it could embed into DNA to block DNA replication but could not cleave DNA. These findings implied that HNs are promising as novel structural scaffolds of potential multitargeting broad-spectrum antifungal candidates for treating fungal infection.

Design and synthesis of Meldrum's acid based 7-azaindole anchored 1,2,3-triazole hybrids as anticancer agents

A series of Meldrum's acid, 7-azaindole and 1,2,3-triazole hybrids were synthesized and evaluated for their in vitro anticancer activity against five different cancer cell lines viz. MCF-7 (breast cancer), HeLa (cervical cancer), DU-145 (prostate cancer), HepG2 (liver cancer) and K562 (myelogenous leukemia cell). Among the series, compound 6b containing a 4-methyl substitution showed potent activity against HeLa cell line. Cell cycle analysis revealed that compound 6b induced cell cycle arrest at the G2/M phase and induced apoptosis. Apoptotic activity was further confirmed by Hoechst staining and Annexin V-FITC assay. Compound 6b has been found to exhibit higher activity in all four cell lines, with IC50 values of 6.67 ± 0.39 μM, 4.44 ± 0.32 μM, 12.38 ± 0.51 μM and 9.97 ± 0.25 μM against MCF-7, HeLa, DU-145 and HepG2 cell lines respectively. Compounds 6m (9.68 ± 0.10 μM) and 6n (9.52 ± 0.38 μM), which have dimethoxy and trimethoxy substitutions, respectively, have demonstrated significant anticancer activity against HeLa cells compared to the other cells. The molecular docking study of ligand 6b against the crystal structure of EGFR and Mcl-1 scored notable binding energy values and displayed important interactions like H-bond, π-cation and other hydrophobic interactions.

Identification of unique indolylcyanoethylenyl sulfonylanilines as novel structural scaffolds of potential antibacterial agents

The increasing incidence of antibiotic resistance has forced the development of unique antimicrobials with novel multitargeting mechanisms to combat infectious diseases caused by multidrug-resistant pathogens. Structurally unique indolylcyanoethylenyl sulfonylanilines (ISs) were exploited as novel promising antibacterial agents to confront stubborn drug resistance. Some prepared ISs possessed favorable bacteriostatic action towards the tested bacteria. Especially, hydroxyethyl IS 14a exerted 8-fold more potent inhibitory efficacy against multidrug-resistant A. baumannii and E. coli 25922 with the low MIC of 0.5 μg/mL than norfloxacin, and showed low cell toxicity and rapid bactericidal property. Moreover, this compound also possessed obvious effect of eradicating bacterial biofilm, which could effectually relieve the development of drug resistance. A preliminary assessment of the antibacterial mechanism indicated that compound 14a could disintegrate membrane integrity leading to the leakage of intracellular protein, inactivation of lactate dehydrogenase and metabolism inhibition. Hydroxyethyl IS 14a mediated the accumulation of excess reactive oxygen species, which further contributed to reducing glutathione, resulting in oxidative damage to bacteria. Furthermore, IS 14a could intercalate into DNA to hinder the biological function of DNA. Quantum chemical study disclosed that IS 14a with the lowest energy gap was conducive to displaying high bioactivity. These findings demonstrated that hydroxyethyl IS 14a as a prospective antimicrobial candidate for combating A. baumannii and E. coli 25922 would be a promising starting point.

New pyrrole derivatives as DNA gyrase and 14α-demethylase inhibitors: Design, synthesis, antimicrobial evaluation, and molecular docking

An efficient one-pot reaction utilizing readily available chemical reagents was used to prepare novel 2-amino-1,5-diaryl-1H-pyrrole-3-carbonitrile derivatives and the structures of these compounds were validated by spectroscopic data and elemental analyses. All the synthetic compounds were evaluated for their antimicrobial activities (MZI assay). The tested compounds proved high activities on Staphylococcus aureus (Gram-positive bacteria) and Candida albicans (Pathogenic fungi). However, they did not show any activity on Escherichia coli (Gram-negative bacteria). The most effective compounds in MZI assay 7c, 9a, 9b, 11a, and 11b were selected to determine their MIC on S. aureus and C. albicans. Furthermore, DNA gyrase and 14-α demethylase inhibitory assays were performed to study the inhibitory activities of 7c, 9a, 9b, 11a, and 11b. The results illustrated that compound 9b was the most DNA gyrase inhibitor (IC50 of 0.0236 ± 0.45 µM, which was 1.3- fold higher than gentamicin reference IC50 values of 0.0323 ± 0.81 µM). In addition, compound 9b demonstrated the highest 14-α demethylase inhibitory effect with IC50 of 0.0013 ± 0.02 µM, compared to ketoconazole (IC50 of 0.0008 ± 0.03 µM) and fluconazole (IC50 of 0.00073 ± 0.01 µM), as antifungal reference drugs. Lastly, docking studies were performed to rationalize the dual inhibitory activities of the highly active compounds on both DNA gyrase and 14-α demethylase enzymes.

Identification of pyrrolo[3',4':3,4]cyclohepta[1,2-d][1,2]oxazoles as promising new candidates for the treatment of lymphomas

Unsatisfactory outcomes for relapsed/refractory lymphoma patients prompt continuing efforts to develop new therapeutic strategies. Our previous studies on pyrrole-based anti-lymphoma agents led us to synthesize a new series of twenty-six pyrrolo[3',4':3,4]cyclohepta[1,2-d] [1,2]oxazole derivatives and study their antiproliferative effects against a panel of four non-Hodgkin lymphoma cell lines. Several candidates showed significant anti-proliferative effects, with IC50's reaching the sub-micromolar range in at least one cell line, with compound 3z demonstrating sub-micromolar growth inhibitory effects towards the entire panel. The VL51 cell line was the most sensitive, with an IC50 value of 0.10 μM for 3z. Our earlier studies had shown that tubulin was a prominent target of many of our oxazole derivatives. We therefore examined their effects on tubulin assembly and colchicine binding. While 3u and 3z did not appear to target tubulin, good activity was observed with 3d and 3p. Molecular docking and molecular dynamics simulations allowed us to rationalize the binding mode of the synthesized compounds toward tubulin. All ligands exhibited a better affinity for the colchicine site, confirming their specificity for this binding pocket. In particular, a better affinity and free energy of binding was observed for 3d and 3p. This result was confirmed by experimental data, indicating that, although both 3d and 3p significantly affected tubulin assembly, only 3d showed activity comparable to that of combretastatin A-4, while 3p was about 4-fold less active. Cell cycle analysis showed that compounds 3u and especially 3z induced a block in G2/M, a strong decrease in S phase even at low compound concentrations and apoptosis through the mitochondrial pathway. Thus, the mechanism of action of 3u and 3z remains to be elucidated. Very high selectivity toward cancer cells and low toxicity in human peripheral blood lymphocytes were observed, highlighting the good potential of these agents in cancer therapy and encouraging further exploration of this compound class to obtain new small molecules as effective lymphoma treatments.

Discovery of novel phenylhydrazone-based oxindole-thiolazoles as potent antibacterial agents toward Pseudomonas aeruginosa

With the soaring of bacterial infection and drug resistance, it is imperative to exploit new efficient antibacterial agents. This work constructed a series of unique phenylhydrazone-based oxindole-thiolazoles to combat monstrous bacterial resistance. Some target molecules showed potent antibacterial activity, among which oxindole-thiolimidazole derived carboxyphenylhydrazone 4e exhibited an 8-fold stronger inhibitory ability than norfloxacin on the growth of P. aeruginosa, with MIC value of 1 μg/mL. Compound 4e with imperceptible hemolysis could hamper bacterial biofilm formation and significantly impede the development of bacterial resistance. Subsequent mechanism studies demonstrated that 4e could destruct bacterial cytoplasmic membrane, causing the leakage of cellular contents (protein and nucleic acid). Moreover, metabolic stagnation and intracellular oxidative stress caused by 4e expedited the death of bacteria. Furthermore, molecule 4e existed supramolecular interactions with DNA to block DNA proliferation. These research results provided a promising light for phenylhydrazone-based oxindole-thiolazoles as novel potential antibacterial agents.

Design, synthesis and structure-activity relationship studies of novel spirochromanone hydrochloride analogs as anticancer agents

Aim: Literature reports suggest spirochromanone derivatives exhibit anticancer activity. Methodology: The authors designed and synthesized 18 spirochromanone derivatives (Csp 1-18). The compounds were characterized and evaluated for anticancer activity against human breast cancer (MCF-7) and murine melanoma (B16F10) cell lines. Results: The anticancer activity ranged from 4.34 to 29.31 μm. The most potent compounds, Csp 12 and Csp 18, were less toxic against the human embryonic kidney (HEK-293) cell line and ∼ two/∼four fold selective toward MCF-7 than B16F10 in comparison to the reference, BG-45. Csp 12 caused 28.6% total apoptosis, leading to significant cytotoxicity, and arrested the G2 phase of the cell cycle in B16F10 cells. A molecular docking study of Csp 12 exhibited effective binding at the active site of the epidermal growth factor receptor kinase domain. Conclusion: This study highlights the importance of spirochromanones as anticancer agents.

A facile reaction to access novel structural sulfonyl-hybridized imidazolyl ethanols as potential DNA-targeting antibacterial agents

A novel type of sulfonyl-hybridized imidazolyl ethanols as potential DNA-targeting antibacterial agents was constructed via the unique ring-opened reaction of oxiranes by imidazoles for the first time. Some developed target hybrids showed potential antimicrobial potency against the tested microbes. Especially, imidazole derivative 5f could strongly suppressed the growth of MRSA (MIC = 4 μg/mL), which was 2-fold and 16-fold more potent than the positive control sulfathiazole and norfloxacin. This compound exhibited quite low propensity to induce bacterial resistance. Antibacterial mechanism exploration indicated that compound 5f could embed in MRSA DNA to form steady 5f-DNA complex, which possibly hinder DNA replication to exert antimicrobial behavior. Molecular docking showed that molecule 5f could bind with dihydrofolate synthetase through hydrogen bonds. These results implied that imidazole derivative 5f could be served as a promising molecule for the exploration of novel antibacterial candidates.

1,2,3-Triazole-Containing Compounds as Anti-Lung Cancer Agents: Current Developments, Mechanisms of Action, and Structure-Activity Relationship

Lung cancer is the most common malignancy and leads to around one-quarter of all cancer deaths. Great advances have been achieved in the treatment of lung cancer with novel anticancer agents and improved technology. However, morbidity and mortality rates remain extremely high, calling for an urgent need to develop novel anti-lung cancer agents. 1,2,3-Triazole could be readily interact with diverse enzymes and receptors in organisms through weak interaction. 1,2,3-Triazole can not only be acted as a linker to tether different pharmacophores but also serve as a pharmacophore. This review aims to summarize the recent advances in 1,2,3-triazole-containing compounds with anti-lung cancer potential, and their structure-activity relationship (SAR) together with mechanisms of action is also discussed to pave the way for the further rational development of novel anti-lung cancer candidates.

Design, synthesis and biological evaluation of 1H-pyrrolo[2,3-b]pyridine derivatives as potent fibroblast growth factor receptor inhibitors

Abnormal activation of FGFR signaling pathway plays an essential role in various types of tumors. Therefore, targeting FGFRs represents an attractive strategy for cancer therapy. Herein, we report a series of 1H-pyrrolo[2,3-b]pyridine derivatives with potent activities against FGFR1, 2, and 3. Among them, compound 4h exhibited potent FGFR inhibitory activity (FGFR1–4 IC₅₀ values of 7, 9, 25 and 712 nM, respectively). In vitro, 4h inhibited breast cancer 4T1 cell proliferation and induced its apoptosis. In addition, 4h also significantly inhibited the migration and invasion of 4T1 cells. Furthermore, 4h with low molecular weight would be an appealing lead compound which was beneficial to the subsequent optimization. In general, this research has been developing a class of 1H-pyrrolo[2,3-b]pyridine derivatives targeting FGFR with development prospects.

Discovery of a new class of 1H- pyrrorole [2,3-b]pyridine FGFR inhibitors with high ligand efficiency.

Molecular design and preparation of 2-aminothiazole sulfanilamide oximes as membrane active antibacterial agents for drug resistant Acinetobacter baumannii

A series of 2-aminothiazole sulfanilamide oximes were developed as new membrane active antibacterial agents to conquer the microbial infection. Benzoyl derivative 10c was preponderant for the treatment of drug-resistant A. baumannii infection in contrast to norfloxacin and exerted excellent biocompatibility against mammalian cells including erythrocyte and LO2 cell line. Meanwhile, it had ability to eradicate established biofilm to alleviate the resistance burden. Mechanism investigation elucidated that compound 10c was able to disturb the membrane effectively and inhibit lactic dehydrogenase, which led to cytoplasmic content leakage. The cellular redox homeostasis was interfered via the production of reactive oxygen and nitrogen species (RONS), which further contributed to respiratory pathway inactivation and reduction of GSH activity. This work indicated that 2-aminothiazole sulfanilamide oximes could be a promising start for the exploitation of novel antibacterial agents against pathogens.

Design, synthesis and biological evaluation of 7-(5-((substituted - amino)-methyl)-thiophen-2-yl)-spiro-[chroman-2,4'-piperidin]-4-one hydrochloride analogues as anticancer agents

A series of thirty-one novel 7-(5-((amino)-methyl)-thiophen-2-yl)-spiro-[chroman-2,4'-piperidin]-4-one hydrochloride analogues (Cst 1 - 31) have been designed, synthesized and characterized by ¹H NMR, ¹³C NMR and MS spectral analysis. Here, we evaluated the anticancer potential and biological results of low-molecular-weight bridgehead oxygen and nitrogen-containing spirochromanones on proliferation and apoptosis of the human breast cancer cell line (MCF-7) and Murine melanoma (B16F10). The anticancer activity ranged from 2.9 to 35.0 µM. The most potent compounds Cst-22, Cst-24 and Cst-31 were found to be less toxic against human embryonic kidney (HEK-293) cell lines. Cst-24 and Cst-31 were found to be causing significant cytotoxicity through apoptotic cell death and also G2 phase arrest of cell cycle in B16F10 cells. In-silico ADME prediction stidies of the titled compounds were found within the rules outlined, and these compounds may not face any pharmacokinetic associated issues in the mere future upon developmental stage. These conjugates may serve as a lead for the discovery of potential anticancer drug candidate with better therapeutic profile.

Unique para-aminobenzenesulfonyl oxadiazoles as novel structural potential membrane active antibacterial agents towards drug-resistant methicillin resistant Staphylococcus aureus

A class of structurally unique para-aminobenzenesulfonyl oxadiazoles as new potential antimicrobial agents was designed and synthesized from acetanilide. Some target para-aminobenzenesulfonyl oxadiazoles showed antibacterial potency. Noticeably, hexyl derivative 8b (MIC = 1 μg/mL) was more active than norfloxacin against drug resistant MRSA. Compound 8b was able to disturb the membrane effectively and intercalate into deoxyribonucleic acid (DNA) to form a steady 8b-DNA complex, which might be responsible for bacterial metabolic inactivation. Molecular docking indicated that 8b could interact with DNA topoisomerase IV through noncovalent interactions to form a supramolecular complex and hinder the function of this enzyme. These results indicated that hexyl derivative 8b deserved further investigation as a new lead compound.

An unexpected discovery toward novel membrane active sulfonyl thiazoles as potential MRSA DNA intercalators

Aim: With the increasing emergence of drug-resistant bacteria, the need for new antimicrobial agents has become extremely urgent. This work was to develop sulfonyl thiazoles as potential antibacterial agents. Results & methodology: Novel hybrids of sulfonyl thiazoles were developed from commercial acetanilide and acetylthiazole. Hybrids 6e and 6f displayed excellent inhibitory efficacy against clinical methicillin-resistant Staphylococcus aureus (MRSA) (minimum inhibitory concentration = 1 μg/ml) without obvious toxicity toward normal mammalian cells (RAW 264.7). The combination uses were found to improve the antimicrobial ability. Further preliminary antibacterial mechanism experiments showed that the active molecule 6f could effectively interfere with MRSA membrane and insert into MRSA DNA. Conclusion: Compounds 6e and 6f could serve as potential DNA-targeting templates toward the development of promising antimicrobial agents.

Bioactive pyrrole-based compounds with target selectivity

The discovery of novel synthetic compounds with drug-like properties is an ongoing challenge in medicinal chemistry. Natural products have inspired the synthesis of compounds for pharmaceutical application, most of which are based on N-heterocyclic motifs. Among these, the pyrrole ring is one of the most explored heterocycles in drug discovery programs for several therapeutic areas, confirmed by the high number of pyrrole-based drugs reaching the market. In the present review, we focused on pyrrole and its hetero-fused derivatives with anticancer, antimicrobial, and antiviral activities, reported in the literature between 2015 and 2019, for which a specific target was identified, being responsible for their biological activity. It emerges that the powerful pharmaceutical and pharmacological features provided by the pyrrole nucleus as pharmacophore unit of many drugs are still recognized by medicinal chemists.

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Pyrrole nucleus is one of the most explored heterocycle in drug discovery.

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Pyrrole derivatives exhibit antitumor, antimicrobial and antiviral activities.

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Targets involved in their biological activities were identified.

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SAR to underline their most important features were discussed.

1,2,3-Triazole-containing hybrids as potential anticancer agents: Current developments, action mechanisms and structure-activity relationships

Anticancer agents are critical for the cancer treatment, but side effects and the drug resistance associated with the currently used anticancer agents create an urgent need to explore novel drugs with low side effects and high efficacy. 1,2,3-Triazole is privileged building block in the discovery of new anticancer agents, and some of its derivatives have already been applied in clinics or under clinical trials for fighting against cancers. Hybrid molecules occupy an important position in cancer control, and hybridization of 1,2,3-triazole framework with other anticancer pharmacophores may provide valuable therapeutic intervention for the treatment of cancer, especially drug-resistant cancer. This review emphasizes the recent advances in 1,2,3-triazole-containing hybrids with anticancer potential, covering articles published between 2015 and 2019, and the structure-activity relationships, together with mechanisms of action are also discussed.

A new exploration towards aminothiazolquinolone oximes as potentially multi-targeting antibacterial agents: Design, synthesis and evaluation acting on microbes, DNA, HSA and topoisomerase IV

This work did a new exploration towards aminothiazolquinolone oximes as potentially multi-targeting antimicrobial agents. A class of novel hybrids of quinolone, aminothiazole, piperazine and oxime fragments were designed for the first time, conveniently synthesized as well as characterized by ¹H NMR, ¹³C NMR and HRMS spectra. Biological activity showed that some of the synthesized compounds exhibited good antimicrobial activities in comparison with the reference drugs. Especially, O-methyl oxime derivative 10b displayed excellent inhibitory efficacy against MRSA and S. aureus 25923 with MIC values of 0.009 and 0.017 mM, respectively. Further studies indicated that the highly active compound 10b showed low toxicity toward BEAS-2B and A549 cell lines and no obvious propensity to trigger the development of bacterial resistance. Quantum chemical studies have also been conducted and rationally explained the structural features essential for activity. The preliminarily mechanism exploration revealed that compound 10b could not only exert efficient membrane permeability by interfering with the integrity of cells, bind with topoisomerase IV-DNA complex through hydrogen bonds and π-π stacking, but also form a steady biosupramolecular complex by intercalating into DNA to exert the efficient antibacterial activity. The supramolecular interaction between compound 10b and human serum albumin (HSA) was a static quenching, and the binding process was spontaneous, where hydrogen bonds and van der Waals force played vital roles in the supramolecular transportation of the active compound 10b by HSA.

Novel naphthalimide nitroimidazoles as multitargeting antibacterial agents against resistant Acinetobacter baumannii

Aim: The increasing emergence of resistant bacteria imposed an urgent request to discover novel antibacterial agents. This work was to develop naphthalimide nitroimidazoles as potentially antibacterial agents. Results/methodology: Compound 9e showed the strong antibacterial activity (minimal inhibitory concentration = 0.013 μmol/ml) against resistant Acinetobacter baumannii (A. baumannii) with rapid killing effect and no obvious triggering of the development of resistance. Its combination use with chloromycin, norfloxacin or clinafloxacin improved the antibacterial potency. It could not only effectively permeate membrane of resistant A. baumannii bacteria, but also intercalate into resistant A. baumannii DNA to form 9e–DNA complex. The interaction with bacterial DNA gyrase B was driven by hydrogen bonds. Conclusion: Compound 9e should be a potentially multitargeting antibacterial agent against resistant A. baumannii.

Cytotoxicity of Aconitum alkaloid and its interaction with calf thymus DNA by multi-spectroscopic techniques

The cytotoxicities of three aconitum alkaloids- aconitine, hypaconitine and mesaconitine, and their abilities to bind DNA have been explored. Rat myocardial cells H9c2 were treated with aconitum alkaloids and assessed the cytotoxicities by using MTT assay and flow cytometry. Apoptosis was evidenced by the results of the annexin V/propidium iodide (PI) assay. Aconitine was found to be the most toxic in rat myocardial cells H9c2 in three aconitum alkaloids. At the same time, DNA adducts were isolated and then analyzed by UV-Vis spectroscopy after exposure to alkaloids, which indicated that three alkaloids could bind to DNA in rat myocardial cells H9c2. Furthermore, their binding modes were investigated by UV-Visible, fluorescence, DNA melting studies and ionic strength effect. Results indicated that the interaction between three alkaloids and DNA were intercalation coupled with electrostatic effect. The estimated binding constants were between 4.83 × 105 M-1 to 9.85 × 105 M-1 for three alkaloids at 298 K.

Multi-targeting exploration of new 2-aminothiazolyl quinolones: Synthesis, antimicrobial evaluation, interaction with DNA, combination with topoisomerase IV and penetrability into cells

A series of new potentially multi-targeting antimicrobial 2-aminothiazolyl quinolones were designed, synthesized and characterized by ¹H NMR, ¹³C NMR, IR, MS and HRMS spectra. Bioactive assay manifested that some of the prepared compounds showed moderate to good antibacterial and antifungal activities. Noticeably, compound 10f could effectively inhibit the growth of B. typhi and MRSA with MIC values of 1 and 8 μg/mL, respectively. Experimental results revealed that compound 10f was membrane-active and had the ability to rapidly kill the tested strains and effectively prevent the development of bacterial resistance. Moreover, this compound also exhibited low toxicity against L929 cells. Molecular docking indicated that compound 10f could bind with topoisomerase IV-DNA complexes through hydrogen bonds and hydrophobic interactions. Quantum chemical studies were also performed on 10f to understand the structural features essential for activity. The preliminary mechanism research suggested that compound 10f could intercalate into calf thymus DNA to form a steady supramolecular complex which might block DNA replication to exert the powerful bioactivities.

Novel Anthra[1,2-c][1,2,5]Thiadiazole-6,11-Diones as Promising Anticancer Lead Compounds: Biological Evaluation, Characterization & Molecular Targets Determination

The novel compounds NSC745885 and NSC757963 developed at our laboratory were tested against a panel of 60 cancer cell lines at the National Cancer Institute, USA, and a panel of 39 cancer cell lines at the Japanese Foundation of Cancer Research. Both compounds demonstrated selective unique multi-log differential patterns of activity, with GI₅₀ values in the sub-micro molar range against cancer cells rather than normal cardiac cells. NSC757963 showed high selectivity towards the leukemia subpanel. Activities of both compounds strongly correlated to expression of NFKB1 and CSNK2B genes, implying that they may inhibit the NF-κB pathway. Immunocytochemical microscopy of OVCAR-3 cells showed clear cytosolic accumulation of the NF-κB p65 subunit following treatment. Western blotting showed dose dependent inhibition of the nuclear expression of the NF-κB p65 subunit with subsequent accumulation in the cytosol following treatment. Docking experiments showed binding of both compounds to the NF-κB activator IKKβ subunit preventing its translocation to the nucleus. Collectively, these results confirm the ability of our compounds to inhibit the constitutively active NF-κB pathway of OVCAR-3 cells. Furthermore, COMPARE analysis indicated that the activity of NSC757963 is similar to the antituberculosis agent rifamycin SV, this was confirmed by testing the antimycobacterial activity of NSC757963 against Mycobacterium tuberculosis, results revealed potent activity suitable for use in clinical practice. Molecular properties and Lipinski’s parameters predicted acceptable bioavailability properties with no indication of mutagenicity, tumorigenicity, irritability and reproductive effects. Oral absorption experiments using the human Caco-2 model showed high intestinal absorption of NSC745885 by passive transport mechanism with no intestinal efflux or active transport mechanisms. The unique molecular characterization as well as the illustrated anticancer spectra of activity and bioavailability properties warrant further development of our compounds and present a foundation brick in the pre-clinical investigations to implement such compounds in clinical practice.

Studies on the structures, cytotoxicity and apoptosis mechanism of 8-hydroxylquinoline rhodium(iii) complexes in T-24 cells

Two rhodium(iii) complexes showed good cytotoxicity. The underlying investigation of the apoptosis mechanism suggested that the mitochondrial apoptotic pathway was involved.