Design, Synthesis, and Biological Evaluation of Novel 1,3,4-Thiadiazole Derivatives as Potential Antitumor Agents against Chronic Myelogenous Leukemia: Striking Effect of Nitrothiazole Moiety

Emerging synthetic strategies and pharmacological insights of 1,3,4-thiadiazole derivatives: a comprehensive review

This review meticulously examines the synthesis techniques for 1,3,4-thiadiazole derivatives, focusing on cyclization, condensation reactions and functional group transformations. It enhances the understanding of these chemical methods that re crucial for tailoring derivative properties and functionalities. This study is considered to be vital for researchers, detailing established effects such as antioxidant, antimicrobial and anticancer activities, and revealing emerging pharmacological potentials such as neuroprotective, antiviral and antidiabetic properties. It also discusses the molecular mechanisms underlying these effects. In addition, this article covers structure-activity relationship studies and computational modelling that are essential for designing potent, selective 1,3,4-thiadiazole compounds. This work lays a foundation for future research and targeted therapeutic development.

Techniques and Strategies in Drug Design and Discovery

The process of drug discovery constitutes a highly intricate and formidable undertaking, encompassing the identification and advancement of novel therapeutic entities [...].

The Progress of Small Molecule Targeting BCR-ABL in the Treatment of Chronic Myeloid Leukemia

Chronic myelogenous leukemia (CML) is a malignant myeloproliferative disease. According to the American Cancer Society's 2021 cancer data report, new cases of CML account for about 15% of all leukemias. CML is generally divided into three stages: chronic phase, accelerated phase, and blast phase. Nearly 90% of patients are diagnosed as a chronic phase. Allogeneic stem cell transplantation and chemotherapeutic drugs, such as interferon IFN-α were used as the earliest treatments for CML. However, they could generate obvious side effects, and scientists had to seek new treatments for CML. A new era of targeted therapy for CML began with the introduction of imatinib, the first-generation BCR-ABL kinase inhibitor. However, the ensuing drug resistance and mutant strains led by T315I limited the further use of imatinib. With the continuous advancement of research, tyrosine kinase inhibitors (TKI) and BCR-ABL protein degraders with novel structures and therapeutic mechanisms have been discovered. From biological macromolecules to classical target protein inhibitors, a growing number of compounds are being developed to treat chronic myelogenous leukemia. In this review, we focus on summarizing the current situation of a series of candidate small-molecule drugs in CML therapy, including TKIs and BCR-ABL protein degrader. The examples provided herein describe the pharmacology activity of small-molecule drugs. These drugs will provide new enlightenment for future treatment directions.

Synthesis of 1,3,4-Thiadiazole Derivatives and Their Anticancer Evaluation

Thiadiazole derivatives have garnered significant attention in the field of medicinal chemistry due to their diverse pharmacological activities, including anticancer properties. This article presents the synthesis of a series of thiadiazole derivatives and investigates their chemical characterization and potential anticancer effects on various cell lines. The results of the nuclear magnetic resonance (NMR) analyses confirmed the successful formation of the target compounds. The anticancer potential was evaluated through in silico and in vitro cell-based assays using LoVo and MCF-7 cancer lines. The assays included cell viability, proliferation, apoptosis, and cell cycle analysis to assess the compounds' effects on cancer cell growth and survival. Daphnia magna was used as an invertebrate model for the toxicity evaluation of the compounds. The results revealed promising anticancer activity for several of the synthesized derivatives, suggesting their potential as lead compounds for further drug development. The novel compound 2g, 5-[2-(benzenesulfonylmethyl)phenyl]-1,3,4-thiadiazol-2-amine, demonstrated good anti-proliferative effects, exhibiting an IC50 value of 2.44 µM against LoVo and 23.29 µM against MCF-7 after a 48-h incubation and little toxic effects in the Daphnia test.

Synthesis and biological assessment of indole derivatives containing penta-heterocycles scaffold as novel anticancer agents towards A549 and K562 cells

Herein, a new series of 2-chloro-N-(5-(2-oxoindolin-3-yl)-4H-pyrazol-3-yl) acetamide derivatives containing 1,3,4-thiadiazole (10a-i) and 4H-1,2,4-triazol-4-amine (11a-r) moiety was designed, synthesised as novel anticancer agents. The antiproliferative activity values indicated that compound 10 b stood as the most potent derivative with IC₅₀ values of 12.0 nM and 10 nM against A549 and K562 cells, respectively. Mechanism investigation and docking studies of 10 b indicated that it possessed good apoptosis characteristic and dose-dependent growth arrest of A549 and K562 cells, blocked cell cycle into G2/M phase. Interestingly, 10 b suppressed the growth of A549 and K562 cells via modulation of EGFR and p53-MDM2 mediated pathway.

Design, synthesis, and biological evaluation of thiazole/thiadiazole carboxamide scaffold-based derivatives as potential c-Met kinase inhibitors for cancer treatment

As part of our continuous efforts to discover novel c-Met inhibitors as antitumor agents, four series of thiazole/thiadiazole carboxamide-derived analogues were designed, synthesised, and evaluated for the in vitro activity against c-Met and four human cancer cell lines. After five cycles of optimisation on structure-activity relationship, compound 51am was found to be the most promising inhibitor in both biochemical and cellular assays. Moreover, 51am exhibited potency against several c-Met mutants. Mechanistically, 51am not only induced cell cycle arrest and apoptosis in MKN-45 cells but also inhibited c-Met phosphorylation in the cell and cell-free systems. It also exhibited a good pharmacokinetic profile in BALB/c mice. Furthermore, the binding mode of 51am with both c-Met and VEGFR-2 provided novel insights for the discovery of selective c-Met inhibitors. Taken together, these results indicate that 51am could be an antitumor candidate meriting further development.

New insight into the bioactivity of substituted benzimidazole derivatives: Repurposing from anti-HIV activity to cell migration inhibition targeting hnRNP M

Drug repurposing is a distinguished approach for drug development that saves a great deal of time and money. Based on our previous successful repurposing of a compound BMMP from anti-HIV-1 therapy to anti-cancer metastatic activity, we adopted the same techniques for repurposing benzimidazole derivatives considering MM-1 as a lead compound. An extensive structure-activity relationship (SAR) study afforded three promising compounds, MM-1d, MM-1h, and MM-1j, which inhibited cell migration in a similar fashion to BMMP. These compounds suppressed CD44 mRNA expression, whereas only MM-1h further suppressed mRNA expression of the epithelial-mesenchymal transition (EMT) marker zeb 1. Using benzimidazole instead of methyl pyrimidine as in BMMP resulted in better affinity for heterogeneous nuclear ribonucleoprotein (hnRNP) M protein and higher anti-cell migration activity. In conclusion, our study identified new agents that surpass the affinity of BMMP for hnRNP M and have anti-EMT activity, which makes them worthy of future attention and optimization.

Effect of Antibiotic Amphotericin B Combinations with Selected 1,3,4-Thiadiazole Derivatives on RPTECs in an In Vitro Model

4-(5-methyl-1,3,4-thiadiazole-2-yl) benzene-1,3-diol (C1) and 4-[5-(naphthalen-1-ylmethyl)-1,3,4-thiadiazol-2-yl] benzene1,3-diol (NTBD) are representative derivatives of the thiadiazole group, with a high antimycotic potential and minimal toxicity against normal human fibroblast cells. The present study has proved its ability to synergize with the antifungal activity of AmB. The aim of this work was to evaluate the cytotoxic effects of C1 or NTBD, alone or in combination with AmB, on human renal proximal tubule epithelial cells (RPTECs) in vitro. Cell viability was assessed with the MTT assay. Flow cytometry and spectrofluorimetric techniques were used to assess the type of cell death and production of reactive oxygen species (ROS), respectively. The ELISA assay was performed to measure the caspase-2, -3, and -9 activity. ATR-FTIR spectroscopy was used to evaluate biomolecular changes in RPTECs induced by the tested formulas. The combinations of C1/NTBD and AmB did not exert a strong inhibitory effect on the viability/growth of kidney cells, as evidenced by the negligible changes in the apoptotic/necrotic rate and caspase activity, compared to the control cells. Both NTBD and C1 displayed stronger anti-oxidant activity when combined with AmB. The relatively low nephrotoxicity of the thiadiazole derivative combinations and the protective activity against AmB-induced oxidative stress may indicate their potential use in the therapy of fungal infections.

The lymphocyte-specific protein tyrosine kinase-specific inhibitor A-770041 attenuates lung fibrosis via the suppression of TGF-β production in regulatory T-cells

Background

Lymphocyte-specific protein tyrosine kinase (Lck) is a member of the Src family of tyrosine kinases. The significance of Lck inhibition in lung fibrosis has not yet been fully elucidated, even though lung fibrosis is commonly preceded by inflammation caused by infiltration of T-cells expressing Lck. In this study, we examined the effect of Lck inhibition in an experimental mouse model of lung fibrosis. We also evaluated the effect of Lck inhibition on the expression of TGF-β1, an inhibitory cytokine regulating the immune function, in regulatory T-cells (Tregs).

Methods

Lung fibrosis was induced in mice by intratracheal administration of bleomycin. A-770041, a Lck-specific inhibitor, was administrated daily by gavage. Tregs were isolated from the lung using a CD4⁺CD25⁺ Regulatory T-cell Isolation Kit. The expression of Tgfb on Tregs was examined by flow cytometry and quantitative polymerase chain reaction. The concentration of TGF-β in bronchoalveolar lavage fluid (BALF) and cell culture supernatant from Tregs was quantified by an enzyme-linked immunosorbent assay.

Results

A-770041 inhibited the phosphorylation of Lck in murine lymphocytes to the same degree as nintedanib. A-770041 attenuated lung fibrosis in bleomycin-treated mice and reduced the concentration of TGF-β in BALF. A flow-cytometry analysis showed that A-770041 reduced the number of Tregs producing TGF-β1 in the lung. In isolated Tregs, Lck inhibition by A-770041 decreased the Tgfb mRNA level as well as the concentration of TGF-β in the supernatant.

Conclusions

These results suggest that Lck inhibition attenuated lung fibrosis by suppressing TGF-β production in Tregs and support the role of Tregs in the pathogenesis of lung fibrosis.

A New 1,2-Naphthoquinone Derivative with Anti-lung Cancer Activity

1,2-Naphthoquinone (2-NQ) is a nucleophile acceptor that non-selectively makes covalent bonds with cysteine residues in various cellular proteins, and is also found in diesel exhaust, an air pollutant. This molecule has rarely been considered as a pharmacophore of bioactive compounds, in contrast to 1,4-naphthoquinone. We herein designed and synthesized a compound named N-(7,8-dioxo-7,8-dihydronaphthalen-1-yl)-2-methoxybenzamide (MBNQ), in which 2-NQ was hybridized with the nuclear factor-κB (NF-κB) inhibitor dehydroxymethylepoxyquinomicin (DHMEQ) as a nucleophile acceptor. Although 50 µM MBNQ did not inhibit NF-κB signaling, 10 µM MBNQ induced cell death in the lung cancer cell line A549, which was insensitive to 2-NQ (10 µM). In contrast, MBNQ was less toxic in normal lung cells than 2-NQ. A mechanistic study showed that MBNQ mainly induced apoptosis, presumably via the activation of p38 mitogen-activated protein kinase (MAPK). Collectively, the present results demonstrate that the introduction of an appropriate substituent into 2-NQ constitutes a new biologically active entity, which will lead to the development of 2-NQ-based drugs.

Biological activity of oxadiazole and thiadiazole derivatives

Abstract

The 5-membered oxadiazole and thiadiazole scaffolds are the most privileged and well-known heterocycles, being a common and essential feature of a variety of natural products and medicinal agents. These scaffolds take up the center position and are the core structural components of numerous drugs that belong to different categories. These include antimicrobial, anti-tubercular, anti-inflammatory, analgesic, antiepileptic, antiviral, and anticancer agents. In this review, we mostly talk about the isomers 1,2,4-oxadiazole and 1,3,4-thiadiazole because they have important pharmacological properties. This is partly because they are chemical and heat resistant, unlike other isomers, and they can be used as bio-isosteric replacements in drug design. We are reviewing the structural modifications of different oxadiazole and thiadiazole derivatives, more specifically, the anti-tubercular and anticancer pharmacological activities reported over the last 5 years, as we have undertaken this as a core area of research. This review article desires to do a thorough study and analysis of the recent progress made in the important biological isomers 1,2,4-oxadiazole and 1,3,4-thiadiazol. This will be a great place to start for future research.

Key points

• Five-membered heterocyclic compound chemistry and biological activity recent survey.

• Synthesis and pharmacological evolution of 1,2,4-oxadiazole and 1,3,4-thiadiazole are discussed in detail.

• The value and significance of heterocyclic compounds in the field of drug designing are highlighted.

Supplementary Information

The online version contains supplementary material available at 10.1007/s00253-022-11969-0.

A New Series of Indeno[1,2-c]pyrazoles as EGFR TK Inhibitors for NSCLC Therapy

Non-small cell lung cancer (NSCLC) is the leading cause of cancer-related death throughout the world. Due to the shortcomings of traditional chemotherapy, targeted therapies have come into prominence for the management of NSCLC. In particular, epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor (TKI) therapy has emerged as a first-line therapy for NSCLC patients with EGFR-activating mutations. In this context, new indenopyrazoles, which were prepared by an efficient microwave-assisted method, were subjected to in silico and in vitro assays to evaluate their potency as EGFR TK-targeted anti-NSCLC agents. Compound 4 was the most promising antitumor agent towards A549 human lung adenocarcinoma cells, with an IC₅₀ value of 6.13 µM compared to erlotinib (IC₅₀ = 19.67 µM). Based on its low cytotoxicity to peripheral blood mononuclear cells (PBMCs), it can be concluded that compound 4 exerts selective antitumor action. This compound also inhibited EGFR TK with an IC₅₀ value of 17.58 µM compared to erlotinib (IC₅₀ = 0.04 µM) and induced apoptosis (56.30%). Taking into account in silico and in vitro data, compound 4 stands out as a potential EGFR TKI for the treatment of NSCLC.

Investigations on Anticancer Potentials by DNA Binding and Cytotoxicity Studies for Newly Synthesized and Characterized Imidazolidine and Thiazolidine-Based Isatin Derivatives

Imidazolidine and thiazolidine-based isatin derivatives (IST-01-04) were synthesized, characterized, and tested for their interactions with ds-DNA. Theoretical and experimental findings showed good compatibility and indicated compound-DNA binding by mixed mode of interactions. The evaluated binding parameters, i.e., binding constant (Kb), free energy change (ΔG), and binding site sizes (n), inferred comparatively greater and more spontaneous binding interactions of IST-02 and then IST-04 with the DNA, among all compounds tested under physiological pH and temperature (7.4, 37 °C). The cytotoxic activity of all compounds was assessed against HeLa (cervical carcinoma), MCF-7 (breast carcinoma), and HuH-7 (liver carcinoma), as well as normal HEK-293 (human embryonic kidney) cell lines. Among all compounds, IST-02 and 04 were found to be cytotoxic against HuH-7 cell lines with percentage cell toxicity of 75% and 66%, respectively, at 500 ng/µL dosage. Moreover, HEK-293 cells exhibit tolerance to the increasing drug concentration, suggesting these two compounds are less cytotoxic against normal cell lines compared to cancer cell lines. Hence, both DNA binding and cytotoxicity studies proved imidazolidine (IST-02) and thiazolidine (IST-04)-based isatin derivatives as potent anticancer drug candidates among which imidazolidine (IST-02) is comparatively the more promising.

A Novel Approach to the Synthesis of 1,3,4-Thiadiazole-2-amine Derivatives

The main purpose of the study was the development of a new method for synthesis of 1,3,4-thiadiazol-2-amine derivatives in a one-pot manner using the reaction between a thiosemicarbazide and carboxylic acid without toxic additives such as POCl₃ or SOCl₂. The reaction was investigated in the presence of polyphosphate ester (PPE). It was found that, in the presence of PPE, the reaction between the thiosemicarbazide and carboxylic acid proceeds in one-pot through three steps with the formation of corresponding 2-amino-1,3,4-thiadiazole. Using the developed approach five, 2-amino-1,3,4-thiadiazoles were synthesized. The structures of all compounds were proven by mass spectrometry, IR, and NMR spectroscopies.

A New Series of Antileukemic Agents: Design, Synthesis, In Vitro and In Silico Evaluation of Thiazole-Based ABL1 Kinase Inhibitors

BACKGROUND

After the approval of imatinib, more than 25 antitumor agents targeting kinases have been approved, and several promising candidates are at various stages of clinical evaluation.

OBJECTIVES

Due to the importance of the thiazole scaffold in targeted anticancer drug discovery, the goal of this work is to identify new thiazolyl hydrazones as potent ABL1 kinase inhibitors for the management of Chronic Myeloid Leukemia (CML).

METHODS

New thiazolyl hydrazones (2a-p) were synthesized and investigated for their cytotoxic effects on the K562 CML cell line. Compounds 2h, 2j and 2l showed potent anticancer activity against K562 cell line. The cytotoxic effects of these compounds on other leukemia (HL-60, MT-2 and Jurkat) and HeLa human cervical carcinoma cell lines were also investigated. Furthermore, their cytotoxic effects on Mitogen-Activated Peripheral Blood Mononuclear Cells (MA-PBMCs) were evaluated to determine their selectivity. Due to its selective and potent anticancer activity, compound 2j was benchmarked for its apoptosis-inducing potential on K562 cell line and inhibitory effects on eight different Tyrosine Kinases (TKs), including ABL1 kinase. In order to investigate the binding mode of compound 2j into the ATP binding site of ABL1 kinase (PDB: 1IEP), a molecular docking study was conducted using MOE 2018.01 program. The QikProp module of Schrödinger's Molecular modelling package was used to predict the pharmacokinetic properties of compounds 2a-p.

RESULTS

4-(4-(Methylsulfonyl)phenyl)-2-[2-((1,3-benzodioxol-4-yl)methylene)hydrazinyl]thiazole (2j) showed antiproliferative activity against K562 cell line with an IC₅₀ value of 8.87±1.93 μM similar to imatinib (IC50= 6.84±1.11μM). Compound 2j was found to be more effective than imatinib on HL-60, Jurkat and MT-2 cells. Compound 2j also showed cytotoxic activity against HeLa cell line similar to imatinib. The higher selectivity index value of compound 2j than imatinib indicated that its antiproliferative activity was selective. Compound 2j also induced apoptosis in K562 cell line more than imatinib. Among eight TKs, compound 2j showed the strongest inhibitory activity against ABL1 kinase enzyme (IC₅₀= 5.37±1.17μM). According to molecular docking studies, compound 2j exhibited high affinity to the ATP binding site of ABL1 kinase, forming significant intermolecular interactions. On the basis of in silico studies, this compound did not violate Lipinski's rule of five and Jorgensen's rule of three.

CONCLUSION

Compound 2j stands out as a potential orally bioavailable ABL1 kinase inhibitor for the treatment of CML.

Discovery and Protein Modeling Studies of Novel Compound Mutations Causing Resistance to Multiple Tyrosine Kinase Inhibitors in Chronic Myeloid Leukemia

OBJECTIVE

BCR-ABL fusion oncogene is the hallmark of chronic myeloid leukemia (CML), causing genomic instability which leads to accumulation of mutations in BCR-ABL as well as other genes. BCR-ABL mutations are the cause of tyrosine kinase inhibitors (TKIs) resistance in CML. Recently, compound BCR-ABL mutations have been reported to resist all FDA approved TKIs. Therefore, finding novel compound BCR-ABL mutations can help and clinically manage CML. Therefore, our objective was to find out novel drug-resistant compound BCR-ABL mutations in CML and carry out their protein modelling studies.

METHODOLOGY

Peripheral blood samples were collected from ten imatinib resistant CML patients receiving nilotinib treatment. BCR-ABL transcript mutations were investigated by employing capillary sequencing. Patient follow-up was carried out using European LeukemiaNet guidelines. Protein modeling  studies were carried out for new compound mutations using PyMol to see the effects of mutations at structural level.

RESULTS

A novel compound mutation (K245N mutation along with G250W mutation) and previously known T351I utation was detected in two of the nilotinib resistance CML patients respectively while in the rest of 8 nilotinib responders, no resistant mutations were detected. Protein modelling studies indicated changes in BCR-ABL mutant protein which may have negatively impacted its binding with nilotinib leading to drug resistance.

CONCLUSION

We report a novel nilotinib resistant BCR-ABL compound mutation (K245N along with G250W mutation) which impacts structural modification in BCR-ABL mutant protein leading to drug resistance. As compound mutations pose a new threat by causing resistance to all FDA approved tyrosine kinase inhibitors in BCR-ABL+ leukemias, our study opens a new direction for in vitro characterization of novel BCR-ABL compound mutations and their resistant to second  generation and third generation TKIs.

Structure activity study of S-trityl-cysteamine dimethylaminopyridine derivatives as SIRT2 inhibitors: Improvement of SIRT2 binding and inhibition

Sirtuin proteins are a highly conserved class of nicotinamide adenine dinucleotide (NAD+)-dependent lysine deacylases. The pleiotropic human isoform 2 of Sirtuins (SIRT2) has been engaged in the pathogenesis of cancer in a plethora of reports around the globe. Thus, SIRT2 modulation is deemed as a promising approach for pharmaceutical intervention. Previously, we reported S-Trityl-l-Cysteine (STLC)-ornamented dimethylaminopyridine chemical entity named STC4 with a significant SIRT2 inhibitory capacity; this was separate from the conventional application of STLC scaffold as a kinesin-5 inhibitor. An interactive molecular docking study of SIRT2 and STC4 showed interaction between Asn168 of SIRT2 and the methyl ester of STC4, that appears to hinder STC4 to reach the selective pocket of the protein unlike strong SIRT2 inhibitor SirReal2. To improve its activity, herein, we utilized S-trityl cysteamine pharmacophore lacking the methyl ester. Nine compounds were synthesized and assayed affording three biopertinent SIRT2 inhibitors, and two of them, STCY1 and STCY6 showed higher inhibitory activity than STC4. These compounds have pronounced anti-proliferative activities against different cancer cell lines. A molecular docking study was executed to shed light on the supposed binding mode of the lead compound, STCY1, into the selective pocket of SIRT2 by interaction of the nitrogen of pyridine ring of the compound and Ala135 of the protein. The outcome of the study exposes that the active compounds are effective intermediates to construct more potent biological agents.

Cytotoxic Properties of 1,3,4-Thiadiazole Derivatives-A Review

During recent years, small molecules containing five-member heterocyclic moieties have become the subject of considerable growing interest for designing new antitumor agents. One of them is 1,3,4-thiadiazole. This study is an attempt to collect the 1,3,4-thiadiazole and its derivatives, which can be considered as potential anticancer agents, reported in the literature in the last ten years.

Thiadiazole derivatives as anticancer agents

In spite of substantial progress made toward understanding cancer pathogenesis, this disease remains one of the leading causes of mortality. Thus, there is an urgent need to develop novel, more effective anticancer therapeutics. Thiadiazole ring is a versatile scaffold widely studied in medicinal chemistry. Mesoionic character of this ring allows thiadiazole-containing compounds to cross cellular membrane and interact strongly with biological targets. Consequently, these compounds exert a broad spectrum of biological activities. This review presents the current state of knowledge on thiadiazole derivatives that demonstrate in vitro and/or in vivo efficacy across the cancer models with an emphasis on targets of action. The influence of the substituent on the compounds' activity is depicted. Furthermore, the results from clinical trials assessing thiadiazole-containing drugs in cancer patients are summarized.

Nano magnetic liposomes-encapsulated parthenolide and glucose oxidase for ultra-efficient synergistic antitumor therapy

Multifunctional nanoplatforms yield extremely high synergistic therapeutic effects on the basis of low biological toxicity. Based on the unique tumor microenvironment (TME), a liposomes (Lips)-based multifunctional antitumor drug delivery system known as GOD-PTL-Lips@MNPs was synthesized for chemotherapy, chemodynamic therapy (CDT), starvation therapy, and magnetic targeting synergistic therapy. Evidence has suggested that parthenolide (PTL) can induce apoptosis and consume excessive glutathione (GSH), thereby increasing the efficacy of chemodynamic therapy. On the other hand, glucose oxidase (GOD) can consume intratumoral glucose, lower pH and increase the level of H₂O₂ in the tumor tissue. Integrated Fe₃O₄ magnetic nanoparticles (MNPs) containing Fe²⁺ and Fe³⁺ effectively catalyzes H₂O₂ to a highly toxic hydroxyl radical (•OH) and provide magnetic targeting. During the course of in vitro and in vivo experiments, GOD-PTL-Lips@MNPs demonstrated remarkable synergistic antitumor efficacy. In particular, in mice receiving a 14 day treatment of GOD-PTL-Lips@MNPs, tumor growth was significantly inhibited, as compared with the control group. Moreover, toxicology study and histological examination demonstrated low biotoxicity of this novel therapeutic approach. In summary, our data suggests great antitumor potential for GOD-PTL-Lips@MNPs which could provide an alternative means of further improving the efficacy of anticancer therapies.

New aryl Schiff bases of thiadiazole derivative of ibuprofen as DNA binders and potential anticancer drug candidates

The work presented in this paper describes the synthesis of two new aryl Schiff bases [(E)-N-(4-(benzyloxy)-3-methoxybenzylidene)-5-(1-(4-isobutylphenyl)ethyl)-1,3,4-thiadiazol-2-amine] (ASB-1) and [(E)-N-(4-(benzyloxy)benzylidene)-5-(1-(4-isobutylphenyl)ethyl)-1,3,4-thiadiazol-2-amine] (ASB-2). These compounds were characterized by different analytical techniques and then studied for DNA binding. Binding studies were carried out at neutral pH (7.0) and at 37 °C by theoretical and experimental methods including DFT, molecular docking, spectroscopy (UV-visible, fluorescence), cyclic voltammetry (CV) and viscometry. Further investigations of these compounds were done on hepatocellular carcinoma; Huh-7 cancer cell line. Binding constant, free energy change and binding site size, i.e. K_b, ΔG and n were evaluated which indicated that both ASB-1 and ASB-2 bind significantly and spontaneously with the DNA. However, data revealed relatively greater binding of ASB-1 with DNA. Spectral and voltammetric results were found supportive of each other. Binding site sizes and viscosity measurements verified the mixed binding mode of interactions as observed in molecular docking analysis, i.e. intercalation with groove binding. DNA binding studies were very well correlated with the in-vitro studies performed on Huh-7 cell line as well as normal HEK-293 cell lines. The compound ASB-1 not only showed greater binding affinity toward DNA but also showed greater anticancer potency with least IC₅₀ value as compared to ASB-2.

Nanomagnetic liposome-encapsulated parthenolide and indocyanine green for targeting and chemo-photothermal antitumor therapy

Aim: To synthesize a drug-delivery system with chemo-photothermal function and magnetic targeting, to validate its antitumor effect. Materials & methods: Parthenolide (PTL), employing chemotherapy and indocyanine green (ICG) providing phototherapy, were encased separately in the lipid and aqueous phases of liposomes (Lips). The Fe₃O₄ nanoparticles (MNPs), endowing magnetic targeting, were modified on the surface of Lips. The antitumor effects were investigated in vitro and in vivo. Results: ICG-PTL-Lips@MNPs showed outstanding synergistic antitumor efficacy in vitro and in vivo. Especially, after 14-day treatment, the tumor volumes decreased significantly and the biotoxicity was very low. Conclusion: The designed ICG-PTL-Lips@MNPs possess synergistic effects of chemotherapy, photothermal and targeting therapy, which are expected to provide an alternative way to further improve antitumor efficacy.

Quantitative assessment of the nature of noncovalent interactions in N-substituted-5-(adamantan-1-yl)-1,3,4-thiadiazole-2-amines: insights from crystallographic and QTAIM analysis

Three adamantane-1,3,4-thiadiazole hybrid derivatives namely; N-ethyl-5-(adamantan-1-yl)-1,3,4-thiadiazole-2-amine I, N-(4-fluorophenyl)-5-(adamantan-1-yl)-1,3,4-thiadiazole-2-amine II and (4-bromophenyl)-5-(adamantan-1-yl)-N-1,3,4-thiadiazole-2-amine III, have been synthesized and crystal structures have been determined at low temperature. The structures revealed that the orientation of the amino group is different in non-halogenated structures. Intra- and intermolecular interactions were characterized on the basis of the quantum theory of atoms-in-molecules (QTAIM) approach. Intermolecular interaction energies for different molecular pairs have been obtained using the PIXEL method. Hirshfeld surface analysis and 2D-fingerprint plots revealed that the relative contributions of different non-covalent interactions are comparable in compounds with halogen (Br and F) substitutions. Crystal structures of II and III show isostructural behaviour with 1D supramolecular constructs. In all three structures, the N-H⋯N hydrogen bond was found to be stronger among other noncovalent interactions. The H-H bonding showed a closed shell in nature and played significant roles in the stabilization of these crystal structures.

Effects of Glycyrrhetic Acid on Human Chronic Myelogenous Leukemia Cells

Objectives

Chronic myelogenous leukemia (CML) is a type of blood cancer that is initially treated with imatinib (first Abl kinase inhibitor). However, some patients with CML develop imatinib resistance. Several new generation drugs have been developed, but do not overcome this problem. Glycyrrhetic acid (GA) is a plant-derived pentacyclic triterpenoid that exhibits multiple pharmacological properties for the treatment of cancers. The current study aimed to investigate the effects of GA on the K562 cell line (Bcr-Abl positive leukemia).

Materials and Methods

The MTT cell proliferation assay was employed to evaluate the cytotoxic effect of GA compared with imatinib (positive control) against leukemia and normal blood cells. For detection of cell death, an apoptotic/necrotic/healthy assay was performed against the K562 cell line. To investigate the kinase inhibitory activity of GA, the Abl1 kinase profiling assay and a molecular docking study were performed.

Results

GA showed Abl kinase inhibitory activity with an IC₅₀ value of 29.2 μM and induced apoptosis in the K562 cell line after 6 h of treatment.

Conclusion

The current findings indicate that this class of plant extract could be a potential candidate for treatment of CML.

Anticancer activity of Turkish marine extracts: a purple sponge extract induces apoptosis with multitarget kinase inhibition activity

Marine natural products have drawn a great deal of attention as a vital source of new drugs for the last five decades. However, marine organisms in the seas surrounding Turkey (the Black Sea, the Aegean Sea and the Mediterranean Sea) haven't been yet extensively explored. In the present study, three marine organisms (Dysidea avara, Microcosmus sabatieri and Echinaster sepositus) were sampled from the Dardanelles (Turkish Straits System, Western Turkey) by scientific divers, transferred to the laboratory and then were extracted with 70% ethanol. The extracts were tested for their cytotoxic effect against K562, KMS-12PE, A549, and A375 cancer cell lines. The sponge extract elicited the most promising cytotoxic activity, thus it was further evaluated against H929, MCF-7, HeLa, and HCT116 cancer cells. Most of the designated cells showed a considerable sensitivity for the sponge extract particularly H929, K562, KMS-12PE and HeLa cells with IC₅₀ less than 10 μg/mL. On the contrary, the other two extracts exhibited no cytotoxic activity on all cells at 100 μg/mL concentration. The sponge extract was tested for its capacity to induce apoptosis in cancer cells and to inhibit a panel of tyrosine kinases showing remarkable results. The outcome of this study represents a platform for discovery of new chemotherapeutic agents of marine natural origin.

Antileukemic Activity of Twig Components of Caucasian Beech in Turkey

Despite the development of a range of anti-cancer agents, cancer diagnoses are still increasing in number, remaining a leading cause of death. Anticancer drug treatment is particularly important for leukemia. We screened Turkish plants and found the unique antileukemic activity of twig components in Turkish Caucasian beech, selectively inducing apoptosis in leukemia cells. This effect is unique among some kinds of beeches, presumably related to oxidative stress. This study would lead to effective use of discarded material, i.e., twig of beech, and a new anti-leukemic drug based on large tree.

Radwan M, E. Ozturk S, Ulusoy NG, Sozer E, E. Ellakwa D, Ocak Z, Can M, F.S. Ali T, I. Abd-Alla H, Yayli N, Tateishi H, Otsuka M, Fujita M. Design, Synthesis and Biological Evaluation of Pentacyclic Triterpene Derivatives: Optimization of Anti-ABL Kinase Activity

Imatinib, an Abelson (ABL) tyrosine kinase inhibitor, is a lead molecular-targeted drug against chronic myelogenous leukemia (CML). To overcome its resistance and adverse effects, new inhibitors of ABL kinase are needed. Our previous study showed that the benzyl ester of gypsogenin (1c), a pentacyclic triterpene, has anti-ABL kinase and a subsequent anti-CML activity. To optimize its activities, benzyl esters of carefully selected triterpenes (PT1-PT6), from different classes comprising oleanane, ursane and lupane, and new substituted benzyl esters of gypsogenin (GP1-GP5) were synthesized. All of the synthesized compounds were purified and charachterized by different spectroscopic methods. Cytotoxicity of the parent triterpenes and the synthesized compounds against CML cell line K562 was examined; revealing three promising compounds PT5, GP2 and GP5 (IC50 5.46, 4.78 and 3.19 μM, respectively). These compounds were shown to inhibit extracellular signal-regulated kinase (ERK) downstream signaling, and induce apoptosis in K562 cells. Among them, PT5 was identified to have in vitro activity (IC50 = 1.44 μM) against ABL1 kinase, about sixfold of 1c, which was justified by molecular docking. The in vitro activities of GP2 and GP5 are less than PT5, hence they were supposed to possess other more mechanisms of cytotoxicity. In general, our design and derivatizations resulted in enhancing the activity against ABL1 kinase and CML cells.

Antiproliferative S-Trityl-l-Cysteine -Derived Compounds as SIRT2 Inhibitors: Repurposing and Solubility Enhancement

S-trityl-l-cysteine (STLC) is a well-recognized lead compound known for its anticancer activity owing to its potent inhibitory effect on human mitotic kinesin Eg5. STLC contains two free terminal amino and carboxyl groups that play pivotal roles in binding to the Eg5 pocket. On the other hand, such a zwitterion structure complicates the clinical development of STLC because of the solubility issues. Masking either of these radicals reduces or abolishes STLC activity against Eg5. We recently identified and characterized a new class of nicotinamide adenine dinucleotide-dependent deacetylase isoform 2 of sirtuin protein (SIRT2) inhibitors that can be utilized as cytotoxic agents based on an S-trityl-l-histidine scaffold. Herein, we propose new STLC-derived compounds that possess pronounced SIRT2 inhibition effects. These derivatives contain modified amino and carboxyl groups, which conferred STLC with SIRT2 bioactivity, representing an explicit repurposing approach. Compounds STC4 and STC11 exhibited half maximal inhibitory concentration values of 10.8 ± 1.9 and 9.5 ± 1.2 μM, respectively, against SIRT2. Additionally, introduction of the derivatizations in this study addressed the solubility limitations of free STLC, presumably due to interruption of the zwitterion structure. Therefore, we could obtain drug-like STLC derivatives that work by a new mechanism of action. The new derivatives were designed, synthesized, and their structure was confirmed using different spectroscopic approaches. In vitro and cellular bioassays with various cancer cell lines and in silico molecular docking and solubility calculations of the synthesized compounds demonstrated that they warrant attention for further refinement of their bioactivity.

Anti-cancer activity of the cell membrane-permeable phytic acid prodrug

Phytic acid (IP6) is an ingredient in cereals and legumes, and limited amounts of this compound are considered to enter the cell and exert anti-cancer effects. These effects have been seen by studying cells treated with around 1-5 mM IP6. However, such a large amount of IP6 chelates metals and changes the pH in cell culture medium. To overcome this problem, we synthesized a prodrug of IP6 (Pro-IP6) and elucidated generation of IP6 from Pro-IP6 in cells. Cellular experiments using Pro-IP6 demonstrated selective anti-cancer effects including apoptosis and inhibition of Akt activation. Furthermore, an in vivo study using mice with adult T-cell leukemia also showed that Pro-IP6 reduced the size of the cancer. Taken together, Pro-IP6 is a useful biological tool and may lead to development of new anti-cancer drugs.

Synthesis and Anticancer Activity of New ((Furan-2-yl)-1,3,4-thiadiazolyl)-1,3,4-oxadiazole Acyclic Sugar Derivatives

New sugar hydrazones incorporating furan and/or 1,3,4-thiadiazole ring systems were synthesized by reaction of the corresponding hydrazide with different aldose sugars. Heterocyclization of the formed hydrazones afforded the derived acyclic nucleoside analogues possessing the 1,3,4-oxadiazoline as modified nucleobase via acetylation followed by the heterocyclization process. The anticancer activity of the synthesized compounds was studied against human liver carcinoma cell (HepG-2) and at human normal retina pigmented epithelium cells (RPE-1). High activities were revealed by compounds 3, 12 and 14 with IC₅₀ values near to that of the reference drug doxorubicin.

Synthesis and Evaluation of a Series of 1,3,4-Thiadiazole Derivatives as Potential Anticancer Agents

BACKGROUND AND METHODS

In an attempt to develop potent antitumor agents, the synthesis of a series of N-(6-substituted benzothiazol-2-yl)-2-[(5-(arylamino)-1,3,4-thiadiazol-2-yl)thio]acetamides (1-14) was described and their cytotoxic effects on A549 human lung adenocarcinoma, MCF-7 human breast adenocarcinoma, HepG2 human hepatocellular carcinoma and NIH/3T3 mouse embryonic fibroblast cell lines were investigated using MTT assay.

RESULTS

Phenyl-substituted compounds (8-14) were found to be more effective than naphthyl-substituted compounds (1-7) on cancer cells. Compounds 8, 9, 10, 12, 13 and 14 were identified as the most potent anticancer agents on MCF-7 and HepG2 cell lines and therefore their effects on DNA synthesis and apoptosis/necrosis in MCF-7 cell line were evaluated. Among these compounds, N-(6-methoxybenzothiazol-2-yl)-2-[(5- (phenylamino)-1,3,4-thiadiazol-2-yl)thio]acetamide (13) was the most selective anticancer agent against MCF-7 and HepG2 cell lines with a SI value of 100. On the other hand, compounds 8, 9, 10, 12, 13 and 14 inhibited DNA synthesis in MCF-7 cell line in a dose-dependent manner. Flow cytometric analyses clearly indicated that the compounds showed significant anticancer activity against MCF-7 cell line via the induction of apoptosis dose dependently.

CONCLUSION

According to in vitro assays, compounds 8, 9, 10, 12, 13 and 14 stand out as promising candidates for further studies.

New SIRT2 inhibitors: Histidine-based bleomycin spin-off

Bleomycin is considered to exert its antitumor activity via DNA cleavage mediated by activated oxygen generated from the iron complex in its chelator moiety. Spin-offs from this moiety, HPH-1Trt and HPH-2Trt, with anti-cancer activities were recently synthesized. In this paper, we developed inhibitors of nicotinamide adenine dinucleotide-dependent deacetylase isoform 2 of Sirtuin protein (SIRT2), based on HPH-1Trt/HPH-2Trt, and aimed to generate new anti-cancer drugs. HPH-1Trt and HPH-2Trt had in vitro anti-SIRT2 inhibitory activity with 50% inhibitory concentration (IC₅₀) values of 5.5 and 8.8 μM, respectively. A structural portion of HPH-1Trt/HPH-2Trt, a tritylhistidine derivative TH-1, had stronger activity (IC₅₀ = 1.7 μM), and thus, fourteen derivatives of TH-1 were synthesized. Among them, TH-3 had the strongest activity (IC₅₀ = 1.3 μM). Selective binding of TH-3 in the pocket of SIRT2 protein was confirmed with a molecular docking study. Furthermore, TH-3 strongly lowered viability of the breast cancer cell line MCF7 with an IC₅₀ of 0.71 μM. A structure-activity relationship study using cell lines suggested that the mechanism of TH-3 to suppress MCF7 cells involves not only SIRT2 inhibition, but also another function. This compound may be a new candidate anti-cancer drug.

Synthesis, theoretical, spectroscopic and electrochemical DNA binding investigations of 1, 3, 4-thiadiazole derivatives of ibuprofen and ciprofloxacin: Cancer cell line studies

Two new 1,3,4-thiadiazole derivatives of ibuprofen and ciprofloxacin namely {(5-(1-(4-isobutylphenyl)ethyl)-1,3,4-thiadiazol-2-amine)} 1 and {(3-(5-amino-1,3,4-thiadiazol-2-yl)-1-cyclopropyl-6-fluoro-7-(piperazin-1-yl)quinolin-4(1H)-one)} 2 were synthesized and characterized by spectroscopic and elemental analysis. DFT and molecular docking were done initially for theoretical binding possibilities of the investigated compounds. In vitro DNA binding investigations were carried out with UV-visible spectroscopic, fluorescence spectroscopic, cyclic voltammetric (CV) experiments under physiological conditions of the stomach (4.7) and blood (7.4) pH and at normal body temperature (37 °C). Both theoretical and experimental results suggested spontaneous and significant intercalative binding of the compounds with DNA. Kinetic and thermodynamic parameters (K_b, ΔG) were evaluated greater for compound 2 which showed comparatively more binding and more spontaneity of 2 than 1 to bind with DNA at both pH values. Binding site sizes were found greater (n > 1) and revealed the possibility of other sites for interactions along with intercalation. Overall results for DNA binding were found more significant for 2 at Stomach (4.7) pH. Viscometric studies further verified intercalation as a prominent binding mode for both compounds. IC₅₀ values obtained from human hepatocellular carcinoma (Huh-7) cell line studies revealed 2 as potent anticancer agent than 1 as value found 25.75 μM (lesser than 50 μM). Theoretical and experimental DNA binding studies showed good correlation with cancer cell (Huh-7) line activity of 1 and 2 and further suggested that these compounds could act as potential anti-cancer drug candidates.

Past, present, and future of Bcr-Abl inhibitors: from chemical development to clinical efficacy

Bcr-Abl inhibitors paved the way of targeted therapy epoch. Imatinib was the first tyrosine kinase inhibitor to be discovered with high specificity for Bcr-Abl protein resulting from t(9, 22)-derived Philadelphia chromosome. Although the specific targeting of that oncoprotein, several Bcr-Abl-dependent and Bcr-Abl-independent mechanisms of resistance to imatinib arose after becoming first-line therapy in chronic myelogenous leukemia (CML) treatment.Consequently, new specific drugs, namely dasatinib, nilotinib, bosutinib, and ponatinib, were rationally designed and approved for clinic to override resistances. Imatinib fine mechanisms of action had been elucidated to rationally develop those second- and third-generation inhibitors. Crystallographic and structure-activity relationship analysis, jointly to clinical data, were pivotal to shed light on this topic. More recently, preclinical evidence on bafetinib, rebastinib, tozasertib, danusertib, HG-7-85-01, GNF-2, and 1,3,4-thiadiazole derivatives lay promising foundations for better inhibitors to be approved for clinic in the near future.Notably, structural mechanisms of action and drug design exemplified by Bcr-Abl inhibitors have broad relevance to both break through resistances in CML treatment and develop inhibitors against other kinases as targeted chemotherapeutics.