Synthetic and Medicinal Perspective of Fused-Thiazoles as Anticancer Agents

Synthesis, Antimicrobial Evaluation, and In Silico Studies of 2-Substituted-Phenyl-3-(5-Aryl/Heteroaryl Substituted Thiazol-2-yl) Thiazolidin-4-One Derivatives

In a one-pot reaction involving 3-(2-aminothiazol-5-yl)-2H-chromen-2-one/5-(naphthalen-1-yl)thiazol-2-amines 5-6 with various substituted aldehydes and mercaptoacetic acid, we obtained the corresponding 2-(4-substituted-phenyl)-3-[5-(2-oxo-2H-chromen-3-yl)thiazol-2-yl] thiazolidin-4-ones 8(a-h) and 2-(4-substituted-phenyl)-3-[5-(naphthalen-1-yl)thiazol-2-yl] thiazolidin-4-ones 9(a-h). The antimicrobial activity of all compounds was evaluated against Pseudomonas aeruginosa (MTCC-424), Salmonella typhi (MTCC-531), Staphylococcus aureus (MTCC-737), and Candida albican (MTCC-227). Molecular docking further supported the findings, which showed that the compounds 8d and 9d had excellent antibacterial action against all tested pathogens.

Efficient Synthesis of Thiazole-Fused Bisnoralcohol Derivatives as Potential Therapeutic Agents

Thiazole derivatives are known for a wide range of therapeutic properties. Bisnoralcohol is an inexpensive natural product obtained by the biodegradation of sterols. This article describes an efficient synthesis of a library of thiazole-fused bisnoralcohol derivatives. These novel compounds have been studied for their antineoplastic and antibacterial properties, which led to the discovery of hit compounds with therapeutic potential. The antibacterial compound is noncytotoxic and nonhemolytic against cancer cell lines and sheep red blood cells, respectively. Several of the antineoplastic compounds showed activity against human cancer cell lines with growth inhibition at submicromolar concentration.

Thiazole, Isatin and Phthalimide Derivatives Tested in vivo against Cancer Models: A Literature Review of the Last Six Years

BACKGROUND

Cancer is a disease characterized by the abnormal multiplication of cells and is the second leading cause of death in the world. The search for new effective and safe anticancer compounds is ongoing due to factors such as low selectivity, high toxicity, and multidrug resistance. Thus, heterocyclic compounds derived from isatin, thiazole and phthalimide that have achieved promising in vitro anticancer activity have been tested in vivo and in clinical trials.

OBJECTIVE

This review focused on the compilation of promising data from thiazole, isatin, and phthalimide derivatives, reported in the literature between 2015 and 2022, with in vivo anticancer activity and clinical trials.

METHODS

A bibliographic search was carried out in the PUBMED, MEDLINE, ELSEVIER, and CAPES PERIODIC databases, selecting relevant works for each pharmacophoric group with in vivo antitumor activity in the last 6 years.

RESULTS

In our study, 68 articles that fit the scope were selected and critically analyzed. These articles were organized considering the type of antitumor activity and their year of publication. Some compounds reported here demonstrated potent antitumor activity against several tumor types.

CONCLUSION

This review allowed us to highlight works that reported promising structures for the treatment of various cancer types and also demonstrated that the privileged structures thiazole, isatin and phthalimide are important in the design of new syntheses and molecular optimization of compounds with antitumor activity.

Synthesis, DPPH Radical Scavenging, Cytotoxic Activity, and Apoptosis Induction Efficacy of Novel Thiazoles and Bis-thiazoles

BACKGROUND

Heterocyclic materials-containing thiazoles exhibited incredible importance in pharmaceutical chemistry and drug design due to their extensive biological properties.

METHODS

Synthesis of thiazoles and bis-thiazoles from the reaction of 2-((6-Nitrobenzo[ d][1,3]dioxol-5-yl)methylene)hydrazine-1-carbothioamide with hydrazonoyl chlorides in dioxane and in the existence of triethylamine as basic catalyst. The antioxidant, in vitro antiproliferative, and cytotoxicity efficacy of thiazoles and bis-thiazoles were measured.

RESULTS

In this work, novel series of 5-methyl-2-(2-(-(6-nitrobenzo[d][1,3]dioxol-5-yl)methylene) hydrazinyl)-4-(aryldiazenyl)thiazoles (4a-f) were prepared via the reaction of hydrazonoyl chlorides 2a-f with 2-((6-nitrobenzo[d][1,3]dioxol-5-yl)methylene)hydrazine-1-carbothioamide (1) in dioxane and employing triethylamine as basic catalyst. Following the same procedure, bisthiazoles (6, 8, and 10) have been synthesized by utilizing bis-hydrazonoyl chlorides (5, 7, and 9) and carbothioamide 1 in a molar ratio (1:2), respectively. The distinctive features in the structure of isolated products were elucidated by spectroscopic tools and elemental analyses. The antioxidant, in vitro anti-proliferative, cytotoxicity, and anti-cancer efficacy of thiazoles and bis-thiazoles were evaluated. Compounds 4d and 4f were the most potent antioxidant agents. Gene expression of apoptosis markers and fragmentation assay of DNA were assessed to explore the biochemical mechanism of synthesized products. Thiazoles significantly inhibited cell growth and proliferation more than bis-thiazoles. They induced apoptosis through induction of apoptotic gene expression P53 and downregulation of antiapoptotic gene expression Bcl-2. Moreover, they induced fragmentation of DNA in cancer cells, indicating that they could be employed as anticancer agents by inhibiting tumor growth and progression and can be considered effective compounds in the strategy of anti-cancer agents' discovery.

CONCLUSION

Synthesis, DPPH Radical Scavenging, Cytotoxic activity, and Apoptosis Induction Efficacy based on Novel Thiazoles and Bis-thiazoles.

Design, synthesis, and antitumor screening of new thiazole, thiazolopyrimidine, and thiazolotriazine derivatives as potent inhibitors of VEGFR-2

New thiazole, thiazolopyrimidine, and thiazolotriazine derivatives 3-12 and 14a-f were synthesized. The newly synthesized analogs were tested for in vitro antitumor activity against HepG2, HCT-116, MCF-7, HeP-2, and Hela cancer cells. Results indicated that compound 5 displayed the highest potency toward the tested cancer cells. Compound 11b possessed enhanced effectiveness over MCF-7, HepG2, HCT-116, and Hela cancer cells. In addition, compounds 4 and 6 showed promising activity toward HCT-116, MCF-7, and Hela cancer cells and eminent activity against HepG2 and HeP-2 cells. Moreover, compounds 3-6 and 11b were tested for their capability to inhibit vascular endothelial growth factor receptor-2 (VEGFR-2) activity. The obtained results showed that compound 5 displayed significant inhibitory activity against VEGFR-2 (half-maximal inhibitory concentration [IC50 ] = 0.044 μM) comparable to sunitinib (IC50  = 0.100 μM). Also, the synthesized compounds 3-6 and 11b were subjected to in vitro cytotoxicity tests over WI38 and WISH normal cells. It was found that the five tested compounds displayed significantly lower cytotoxicity than doxorubicin toward normal cell lines. Cell cycle analysis proved that compound 5 induces cell cycle arrest in the S phase for HCT-116 and Hela cancer cell lines and in the G2/M phase for the MCF-7 cancer cell line. Moreover, compound 5 induced cancer cell death through apoptosis accompanied by a high ratio of BAX/BCL-2 in the screened cancer cells. Furthermore, docking results revealed that compound 5 showed the essential interaction bonds with VEGFR-2, which agreed with in vitro enzyme assay results. In silico studies showed that most of the analyzed compounds complied with the requirements of good oral bioavailability with minimal toxicity threats in humans.

Fennel affects porcine ovarian cell functions: The interrelationships with the environmental contaminant benzene

The objective of this study was to examine the direct effects of the medicinal plant fennel on basic functions of ovarian cells, including proliferation, apoptosis, and release of progesterone and insulin-like growth factor I (IGFI), as well as to prevent the influence of the environmental contaminant benzene on these cells. Porcine ovarian granulosa cells were cultured with or without fennel extract alone or in combination with benzene. The expression of the proliferation marker PCNA and the apoptosis marker bax was analyzed by quantitative immunocytochemistry and enzyme-linked immunosorbent assay (ELISA). Fennel was able to promote proliferation and IGF-I release, but to suppress apoptosis and progesterone release. Benzene promoted the accumulation of both the proliferation and apoptosis markers, as well as IGF-I release, but it inhibited progesterone secretion. The presence of fennel did not prevent the effects of benzene on any of the measured parameters, while benzene prevented the effects of fennel on cell proliferation, apoptosis, and IGF-I but not progesterone output. These observations demonstrate the direct influence of fennel and benzene on basic ovarian cell functions. Furthermore, they show the inability of fennel to prevent the effects of benzene on these cells. On the other hand, the environmental contaminant benzene can block the response of ovarian cells to the medicinal plant fennel.

2-Aminothiazole-Flavonoid Hybrid Derivatives Binding to Tau Protein and Responsible for Antitumor Activity in Glioblastoma

Tau protein has been described for several decades as a promoter of tubulin assembly into microtubules. Dysregulation or alterations in Tau expression have been related to various brain cancers, including the highly aggressive and lethal brain tumor glioblastoma multiform (GBM). In this respect, Tau holds significant promise as a target for the development of novel therapies. Here, we examined the structure-activity relationship of a new series of seventeen 2-aminothiazole-fused to flavonoid hybrid compounds (TZF) on Tau binding, Tau fibrillation, and cellular effects on Tau-expressing cancer cells. By spectrofluorometric approach, we found that two compounds, 2 and 9, demonstrated high affinity for Tau and exhibited a strong propensity to inhibit Tau fibrillation. Then, the biological activity of these compounds was evaluated on several Tau-expressing cells derived from glioblastoma. The two lead compounds displayed a high anti-metabolic activity on cells related to an increased fission of the mitochondria network. Moreover, we showed that both compounds induced microtubule bundling within newly formed neurite-like protrusions, as well as with defection of cell migration. Taken together, our results provide a strong experimental basis to develop new potent molecules targeting Tau-expressing cancer cells, such as GBM.

Antitumor Activity of PEGylated and TEGylated Phenothiazine Derivatives: Structure–Activity Relationship

The paper aims to investigate the antitumor activity of a series of phenothiazine derivatives in order to establish a structure–antitumor activity relationship. To this end, PEGylated and TEGylated phenothiazine have been functionalized with formyl units and further with sulfonamide units via dynamic imine bonds. Their antitumor activity was monitored in vitro against seven human tumors cell lines and a mouse one compared to a human normal cell line by MTS assay. In order to find the potential influence of different building blocks on antitumor activity, the antioxidant activity, the ability to inhibit farnesyltransferase and the capacity to bind amino acids relevant for tumor cell growth were investigated as well. It was established that different building blocks conferred different functionalities, inducing specific antitumor activity against the tumor cells.

Synthesis and Development of N-2,5-Dimethylphenylthioureido Acid Derivatives as Scaffolds for New Antimicrobial Candidates Targeting Multidrug-Resistant Gram-Positive Pathogens

The growing antimicrobial resistance to last-line antimicrobials among Gram-positive pathogens remains a major healthcare emergency worldwide. Therefore, the search for new small molecules targeting multidrug-resistant pathogens remains of great importance. In this paper, we report the synthesis and in vitro antimicrobial activity characterisation of novel thiazole derivatives using representative Gram-negative and Gram-positive strains, including tedizolid/linezolid-resistant S. aureus, as well as emerging fungal pathogens. The 4-substituted thiazoles 3h, and 3j with naphthoquinone-fused thiazole derivative 7 with excellent activity against methicillin and tedizolid/linezolid-resistant S. aureus. Moreover, compounds 3h, 3j and 7 showed favourable activity against vancomycin-resistant E. faecium. Compounds 9f and 14f showed broad-spectrum antifungal activity against drug-resistant Candida strains, while ester 8f showed good activity against Candida auris which was greater than fluconazole. Collectively, these data demonstrate that N-2,5-dimethylphenylthioureido acid derivatives could be further explored as novel scaffolds for the development of antimicrobial candidates targeting Gram-positive bacteria and drug-resistant pathogenic fungi.

Discovery of 5-Methylthiazole-Thiazolidinone Conjugates as Potential Anti-Inflammatory Agents: Molecular Target Identification and In Silico Studies

A series of previously synthesized 5-benzyliden-2-(5-methylthiazole-2-ylimino)thiazoli- din-4-one were evaluated for their anti-inflammatory activity on the basis of PASS predictive outcomes. The predictive compounds were found to demonstrate moderate to good anti-inflammatory activity, and some of them displayed better activity than indomethacin used as the reference drug. Structure-activity relationships revealed that the activity of compounds depends not only on the nature of the substituent but also on its position in the benzene ring. The most active compounds were selected to investigate their possible mechanism of action. COX and LOX activity were determined and found that the title compounds were active only to COX-1 enzymes with an inhibitory effect superior to the reference drug naproxen. As for LOX inhibitory activity, the derivatives failed to show remarkable LOX inhibition. Therefore, COX-1 has been identified as the main molecular target for the anti-inflammatory activity of our compounds. The docking study against COX-1 active site revealed that the residue Arg 120 was found to be responsible for activity. In summary, the 5-thiazol-based thiazolidinone derivatives have been identified as a novel class of selective COX-1 inhibitors.

Evaluation of anti-glioma effects of benzothiazoles as efficient apoptosis inducers and DNA cleaving agents

Glioma is the fast-growing, aggressive, and prevalent brain cancer with a great level of morbidity and mortality. Current therapy is usually found insufficient for glioma treatment. In the course of our research attempting to identify effective anti-glioma agents, three benzothiazole derivatives (1-3) were examined on U251 glioma cells. Among these derivatives, compound 3 was found to have the strongest cytotoxic effect on glioma cells with an IC₅₀ value of 9.84 ± 0.64 μM in reference to cisplatin (IC₅₀ = 8.41 ± 1.27 μM). Further mechanism of anti-glioma effects of compound 3 was characterized by the determination of its apoptotic effects in glioma cells and DNA cleaving capacity. Compound 3 caused a significant apoptotic death of U251 cell line. Besides, this compound cleaved DNA with FeSO₄, H₂O₂ and ascorbic acid system. Molecular docking results also showed that compound 3 possessed a significant binding potential to DNA via important π-π stacking interaction with DG-16. Some pharmacokinetic determinants of compound 3 complied with standard limits making it as an efficient bioavailable anti-glioma drug candidate for upcoming exploration.

Recent updates on the anticancer activity of quinoxaline hybrids (Jan. 2017-Jan. 2022)

Abstract:

Cancer as one of the leading causes of death among non-communicable diseases has already posed a heavy burden on the world health system. Chemotherapy is one of the most effective approaches for cancer treatment, but multidrug resistance, lack of efficacy, and toxic side effects hamper efficacious cancer chemotherapy, creating an urgent need to develop novel, more effective and less toxic anticancer therapeutics. Quinoxalines as fascinating structures constitute an important class of heterocycles in drug discovery. Quinoxaline hybrids could exert anticancer activity through diverse mechanisms and possess profound in vitro and in vivo efficacy against various cancers including multidrug-resistant forms. Thus, quinoxaline hybrids represent useful templates for the control and eradication of cancer. The purpose of the present review article is to provide an emphasis on the recent developments (Jan. 2017-Jan. 2022) in quinoxaline hybrids with insights into their in vitro and in vivo anticancer potential as well as structure-activity relationships (SARs) to facilitate further rational design of more effective candidates.

Pyrrolo[2,1-f][1,2,4]triazine: a promising fused heterocycle to target kinases in cancer therapy

Cancer is the second leading cause of death worldwide responsible for about 10 million deaths per year. To date several approaches have been developed to treat this deadly disease including surgery, chemotherapy, radiation therapy, hormonal therapy, targeted therapy, and synthetic lethality. The targeted therapy refers to targeting only specific proteins or enzymes that are dysregulated in cancer rather than killing all rapidly dividing cells, has gained much attention in the recent past. Kinase inhibition is one of the most successful approaches in targeted therapy. As of 30 March 2021, FDA has approved 65 small molecule protein kinase inhibitors and most of them are for cancer therapy. Interestingly, several kinase inhibitors contain one or more fused heterocycles as part of their structures. Pyrrolo[2,1-f][1,2,4]triazine is one the most interesting fused heterocycle that is an integral part of several kinase inhibitors and nucleoside drugs viz. avapritinib and remdesivir. This review articles focus on the recent advances made in the development of kinase inhibitors containing pyrrolo[2,1-f][1,2,4]triazine scaffold.