Synthesis, cytotoxic evaluation and molecular docking study of 2-alkylthio-4-(2,3,4-trimethoxyphenyl)-5-aryl-thiazoles as tubulin polymerization inhibitors

In vitro activity, ultrastructural analysis and in silico pharmacokinetic properties (ADMET) of thiazole compounds against adult worms of Schistosoma mansoni

The present work aimed to carry out in vitro biological assays of thiazole compounds against adult worms of Schistosoma mansoni, as well as the in silico determination of pharmacokinetic parameters to predict the oral bioavailability of these compounds. In addition to presenting moderate to low cytotoxicity against mammalian cells, thiazole compounds are not considered hemolytic. All compounds were initially tested at concentrations ranging from 200 to 6.25 μM against adult worms of S. mansoni parasites. The results showed the best activity of PBT2 and PBT5 at a concentration of 200 μM, which caused 100% mortality after 3 h of incubation. While at 6 h of exposure, 100% mortality was observed at the concentration of 100 µM. Subsequent studies with these same compounds allowed classifying PBT5, PBT2, PBT6 and PBT3 compounds, which were considered active and PBT1 and PBT4 compounds, which were considered inactive. In the ultrastructural analysis the compounds PBT2 and PBT5 (200 µM) promoted integumentary changes with exposure of the muscles, formation of integumentary blisters, integuments with abnormal morphology and destruction of tubercles and spicules. Therefore, the compounds PBT2 and PBT5 are promising antiparasitics against S. mansoni.

Design, Synthesis, and Antipoliferative Activities of Novel Substituted Imidazole-Thione Linked Benzotriazole Derivatives

A new series of benzotriazole moiety bearing substituted imidazol-2-thiones at N1 has been designed, synthesized and evaluated for in vitro anticancer activity against the different cancer cell lines MCF-7(breast cancer), HL-60 (Human promyelocytic leukemia), and HCT-116 (colon cancer). Most of the benzotriazole analogues exhibited promising antiproliferative activity against tested cancer cell lines. Among all the synthesized compounds, BI9 showed potent activity against the cancer cell lines such as MCF-7, HL-60 and HCT-116 with IC₅₀ 3.57, 0.40 and 2.63 µM, respectively. Compound BI9 was taken up for elaborate biological studies and the HL-60 cells in the cell cycle were arrested in G₂/M phase. Compound BI9 showed remarkable inhibition of tubulin polymerization with the colchicine binding site of tubulin. In addition, compound BI9 promoted apoptosis by regulating the expression of pro-apoptotic protein BAX and anti-apoptotic proteins Bcl-2. These results provide guidance for further rational development of potent tubulin polymerization inhibitors for the treatment of cancer.

Design, synthesis and biological evaluation of novel thiazole-naphthalene derivatives as potential anticancer agents and tubulin polymerisation inhibitors

A novel series of thiazole-naphthalene derivatives as tubulin polymerisation inhibitors were designed, synthesised, and evaluated for the anti-proliferative activities. The majority of the tested compounds exhibited moderate to potent antiproliferative activity on the MCF-7 and A549 cancer cell lines. Among them, compound 5b was found to be the most active compound with IC₅₀ values of 0.48 ± 0.03 and 0.97 ± 0.13 μM. Moreover, mechanistic studies revealed that 5b significantly inhibited tubulin polymerisation with an IC₅₀ value of 3.3 µM, as compared to the standard drug colchicine (IC₅₀ = 9.1 μM). Further cellular mechanism studies elucidated that 5b arrested the cell cycle at G2/M phase and induced apoptosis in MCF-7 cancer cells. Molecular modelling study indicated that 5b binds well to the colchicine binding site of tubulin. In summary, these results suggest that 5b represents a promising tubulin polymerisation inhibitor worthy of further investigation as potential anticancer agents.

Triarylpyrazole Derivatives as Potent Cytotoxic Agents; Synthesis and Bioactivity Evaluation "Pyrazole Derivatives as Anticancer Agent"

BACKGROUND

During the last recent years, several anti-cancer agents were introduced for the treatment of diverse kinds of cancer. Despite their potential in the treatment of cancer, drug resistance and adverse toxicity such as peripheral neuropathy are some of the negative criteria of anti-cancer agents and for this reason, the design and synthesis of new anti-cancer agents are important.

OBJECTIVE

Design, synthesis, and anticancer activity evaluation of some pyrazole derivatives.

METHODS

A series of Target compounds were prepared using multistep synthesis. Their cytotoxic activity against three different human cancer cell lines namely human colon carcinoma cells (HT-29), epithelial carcinoma cells (U-87MG), pancreatic cancerous cells (Panc-1) as well as AGO1522 normal cell line using in vitro 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay was investigated.

RESULTS

1,3-Diaryl-5-(3,4,5-trimethoxyphenyl)-4,5-dihydro-1H-pyrazole and 1,3-Diaryl-5-(3,4,5-trimethoxyphenyl)- 1H-pyrazole were synthesized in good yields and their structure and purity were confirmed using ¹H-NMR, ¹³C-NMR, and elemental analysis. Generally, the synthesized scaffolds exhibited good cytotoxicity against cancerous cell lines in comparison to the reference standard, paclitaxel. Compounds 3A: and 3C: , in Annexin V/ PI staining assay, exerted remarkable activity in apoptosis induction in HT-29 cell lines. Both of them also led to cell cycle arrest in the sub-G1 phase which is inconsistent with the results of apoptosis assay.

CONCLUSION

Concerning obtained results, it is interesting to synthesis more pyrazole derivatives as anticancer agents.

Design, synthesis, and evaluation of new 2-oxoquinoline arylaminothiazole derivatives as potential anticancer agents

A series of novel 2-oxoquinoline derivatives containing arylaminothiazole were designed and synthesized as potential antitumor agents. The synthesized compounds were evaluated for their in vitro cytotoxicity activity against HeLa, NCI-H460, T24 and SKOV3 cancer cell lines using MTT assay. Among them, compound A7 exhibited the most potent activity against the test cancer cell lines, with the IC₅₀ values ranged from 4.4 to 8.7 µM. The results of tubulin polymerization assay showed that compound A7 could inhibit tubulin polymerization in vitro. Meanwhile, molecular docking study revealed that A7 can bind to the colchicine site of tubulin and formed hydrogen bonds with key amino acid residues in the active site. Further mechanism study demonstrated that compound A7 blocked cell cycle arrest at G2/M phase, induced cell apoptosis and depolarized mitochondria of HeLa cells. Collectively, our findings suggest that A7 could serve as a promising lead for the development of more efficient microtubule polymerization inhibitors for cancer therapy.

Exploring Diverse-Ring Analogues on Combretastatin A4 (CA-4) Olefin as Microtubule-Targeting Agents

Combretastatin-4 (CA-4) as a tubulin polymerization inhibitor draws extensive attentions. However, due to its weak stability of cis-olefin and poor metabolic stability, structure modifications on cis-configuration are being performed. In this work, we constructed a series of novel CA-4 analogues with linkers on olefin containing diphenylethanone, cis-locked dihydrofuran, α-substituted diphenylethanone, cyclobutane and cyclohexane on its cis-olefin. Cytotoxic activity of all analogues was measured by an SRB assay. Among them, compound 6b, a by-product in the preparation of diphenylethanone analogues, was found to be the most potent cytotoxic agents against HepG2 cells with IC₅₀ values of less than 0.5 μM. The two isomers of 6b induced cellular apoptosis tested by Annexin V-FITC and propidium iodide (PI) double staining, arrested cells in the G2/M phase by PI staining analysis, and disrupted microtubule network by immunohistochemistry study in HepG2 cells. Moreover, 6b-(E) displayed a dose-dependent inhibition effect for tubulin assembly in in vitro tubulin polymerization assay. In addition, molecular docking studies showed that two isomers of 6b could bind efficiently at colchicine binding site of tubulin similar to CA-4.

Thiazole-containing compounds as therapeutic targets for cancer therapy

In the last few decades, considerable progress has been made in anticancer agents development, and several new anticancer agents of natural and synthetic origin have been produced. Among heterocyclic compounds, thiazole, a 5-membered unique heterocyclic motif containing sulphur and nitrogen atoms, serves as an essential core scaffold in several medicinally important compounds. Thiazole nucleus is a fundamental part of some clinically applied anticancer drugs, such as dasatinib, dabrafenib, ixabepilone, patellamide A, and epothilone. Recently, thiazole-containing compounds have been successfully developed as possible inhibitors of several biological targets, including enzyme-linked receptor(s) located on the cell membrane, (i.e., polymerase inhibitors) and the cell cycle (i.e., microtubular inhibitors). Moreover, these compounds have been proven to exhibit high effectiveness, potent anticancer activity, and less toxicity. This review presents current research on thiazoles and elucidates their biological importance in anticancer drug discovery. The findings may aid researchers in the rational design of more potent and bio-target specific anticancer drug molecules.

Synthesis, Anti-proliferative Evaluation, and Molecular Docking Studies of 3-(alkylthio)-5,6-diaryl-1,2,4-triazines as Tubulin Polymerization Inhibitors

Background:

The role of microtubules in cell division and signaling, intercellular transport, and mitosis has been well known. Hence, they have been targeted for several anti-cancer drugs.

Methods:

A series of 3-(alkylthio)-5,6-diphenyl-1,2,4-triazines were prepared and evaluated for their cytotoxic activities in vitro against three human cancer cell lines; human colon carcinoma cells HT-29, human breast adenocarcinoma cell line MCF-7, human Caucasian gastric adenocarcinoma cell line AGS as well as fibroblast cell line NIH-3T3 by MTT assay. Docking simulation was performed to insert these compounds into the crystal structure of tubulin at the colchicine binding site to determine a probable binding model. Compound 5d as the most active compound was selected for studying of microtubule disruption.

Results:

Compound 5d showed potent cytotoxic activity against all cell lines. The molecular modeling study revealed that some derivatives of triazine strongly bind to colchicine binding site. The tubulin polymerization assay kit showed that the cytotoxic activity of 5d may be related to inhibition of tubulin polymerization.

Conclusion:

The cytotoxicity and molecular modeling study of the synthesized compounds with their inhibition activity in tubulin polymerization demonstrate the potential of triazine derivatives for development of new anti-cancer agents.

Constructing novel dihydrofuran and dihydroisoxazole analogues of isocombretastatin-4 as tubulin polymerization inhibitors through [3+2] reactions

[3+2] reactions play a key role in constructing various pharmaceutical moleculars. In this study, using Mn(OAc)₃ mediated and 1,3-dipolar [3+2] cyclization reactions, 38 novel dihydrofuran and dihydroisoxazole analogues of isoCA-4 were synthesized as inhibitors of tubulin polymerization. Among them, compound 6g was found to be the most potent cytotoxic agents against PC-3 cells with IC₅₀ value of 0.47μM, and compound 5p exhibted highest activity on HeLa cells with IC₅₀ vaule of 2.32µM. Tubulin polymerization assay revealed that 6g was a dose-dependent and effective inhibitor of tubulin assembly. Immunohistochemistry studies and cell cycle distribution analysis indicated that 6g severely disrupted microtubule network and significantly arrested most cells in the G2/M phase of the cell cycle in PC-3 cells. In addition, molecular docking studies showed that two chiral isomers of 6g can bind efficiently and similarly at colchicine binding site of tubulin.

Recent advances in combretastatin based derivatives and prodrugs as antimitotic agents

The dynamic and crucial role of tubulin in different cellular functions rendered it a promising target in anticancer drug development. Combretastatin A-4 (CA-4), an inhibitor of tubulin polymerization isolated from natural sources, is a lead molecule with significant cytotoxicity against tumour cells. Owing to its non polar nature it exhibits low solubility in natural biological fluids, thereby prompting the development of new CA-4 based derivatives. The modification of this lead molecule was mostly carried out by keeping the crucial cis-orientation of the double bond intact, along with a trimethoxyphenyl aromatic ring, by employing different approaches. The issue of solubility was also addressed by the development of water soluble prodrugs of CA-4. The present review highlights the investigations into the parallel development of both new CA-4 based derivatives and prodrugs in the past few years.

Enantioselective construction of novel chiral spirooxindoles incorporating a thiazole nucleus

Enantioselective synthesis of novel thiazole-fused spirooxindoles has been realized via chiral thiourea catalyzed asymmetric cascade Michael addition/cyclization of thiazolones and 3-ylideneoxindoles.

Combretastatins: more than just vascular targeting agents?

Several prodrugs of the naturally occurring combretastatins have undergone extensive clinical evaluation as vascular targeting agents (VTAs). Their increased selectivity toward endothelial cells together with their innate ability to rapidly induce vascular shutdown and inhibit tumor growth at doses up to 10-fold less than the maximum tolerated dose led to the clinical evaluation of combretastatins as VTAs. Tubulin is well established as the molecular target of the combretastatins and the vast majority of its synthetic derivatives. Furthermore, tubulin is a highly validated molecular target of many direct anticancer agents routinely used as front-line chemotherapeutics. The unique vascular targeting properties of the combretastatins have somewhat overshadowed their development as direct anticancer agents and the delineation of the various cell death pathways and anticancer properties associated with such chemotherapeutics. Moreover, the ongoing clinical trial of OXi4503 (combretastatin-A1 diphosphate) together with preliminary preclinical evaluation for the treatment of refractory acute myelogenous leukemia has successfully highlighted both the indirect and direct anticancer properties of combretastatins. In this review, we discuss the development of the combretastatins from nature to the clinic. The various mechanisms underlying combretastatin-induced cell cycle arrest, mitotic catastrophe, cell death, and survival are also reviewed in an attempt to further enhance the clinical prospects of this unique class of VTAs.

Synthesis of aryl dihydrothiazol acyl shikonin ester derivatives as anticancer agents through microtubule stabilization

The high incidence of cancer and the side effects of traditional anticancer drugs motivate the search for new and more effective anticancer drugs. In this study, we synthesized 17 kinds of aryl dihydrothiazol acyl shikonin ester derivatives and evaluated their anticancer activity through MTT assay. Among them, C13 showed better antiproliferation activity with IC50=3.14 ± 0.21 μM against HeLa cells than shikonin (IC50=5.75 ± 0.47 μM). We then performed PI staining assay, cell cycle distribution, and cell apoptosis analysis for C13 and found that it can cause cell arrest in G2/M phase, which leads to cell apoptosis. This derivative can also reduce the adhesive ability of HeLa cells. Docking simulation and confocal microscopy assay results further indicated that C13 could bind well to the tubulin at paclitaxel binding site, leading to tubulin polymerization and mitotic disruption.

Recent applications of 1,3-thiazole core structure in the identification of new lead compounds and drug discovery

1,3-Thiazole is one of the most important scaffolds in heterocyclic chemistry and drug design and discovery. It is widely found in diverse pharmacologically active substances and in some naturally-occurring compounds. Thiazole is a versatile building-block for lead generation, and is easily access of diverse derivatives for subsequent lead optimization. In the recent years, many thiazole derivatives have been synthesized and subjected to varied biological activities. In this article we intended to review the most important biological effects of thiazole-based compounds and highlight their roles in new leads identification and drug discovery. This article is also intended to help researches for finding potential future directions on the development of more potent and specific analogs of thiazole-based compounds for various biological targets.

Semi-synthesis and anti-lung cancer activity evaluation of aryl dihydrothiazol acyl podophyllotoxin ester derivatives

S12, the best anticancer agent among the 17 podophyllotoxin derivatives, showed a proliferative inhibition effect via inhibiting tubulin polymerization.