Targeting EGFR tyrosine kinase: Synthesis, in vitro antitumor evaluation, and molecular modeling studies of benzothiazole-based derivatives

Benzothiazole derivatives in the design of antitumor agents

Benzothiazoles are a class of heterocycles with multiple applications as anticancer, antibiotic, antiviral, and anti-inflammatory agents. Benzothiazole is a privileged scaffold in drug discovery programs for modulating a variety of biological functions. This review focuses on the design and synthesis of new benzothiazole derivatives targeting hypoxic tumors. Cancer is a major health problem, being among the leading causes of death. Tumor-hypoxic areas promote proliferation, malignancy, and resistance to drug treatment, leading to the dysregulation of key signaling pathways that involve drug targets such as vascular endothelial growth factor, epidermal growth factor receptor, hepatocyte growth factor receptor, dual-specificity protein kinase, cyclin-dependent protein kinases, casein kinase 2, Rho-related coil formation protein kinase, tunica interna endothelial cell kinase, cyclooxygenase-2, adenosine kinase, lysophosphatidic acid acyltransferases, stearoyl-CoA desaturase, peroxisome proliferator-activated receptors, thioredoxin, heat shock proteins, and carbonic anhydrase IX/XII. In turn, they regulate angiogenesis, proliferation, differentiation, and cell survival, controlling the cell cycle, inflammation, the immune system, and metabolic alterations. A wide diversity of benzothiazoles were reported over the last years to interfere with various proteins involved in tumorigenesis and, more specifically, in hypoxic tumors. Many hypoxic targets are overexpressed as a result of the hypoxia-inducible factor activation cascade and may not be present in normal tissues, providing a potential strategy for selectively targeting hypoxic cancers.

Lead Optimization of BIBR1591 To Improve Its Telomerase Inhibitory Activity: Design and Synthesis of Novel Four Chemical Series with In Silico, In Vitro, and In Vivo Preclinical Assessments

Herein, modifications to the previously reported BIBR1591 were conducted to obtain bioisosteric candidates with improved activities. The % inhibition of the newly afforded candidates against the telomerase target was investigated. Notably, 6f achieved superior telomerase inhibition (63.14%) compared to BIBR1532 and BIBR1591 (69.64 and 51.58%, respectively). In addition, 8a and 8b showed comparable promising telomerase inhibition with 58.65 and 55.57%, respectively, which were recorded to be frontier to that of BIBR1591. 6f, 8a, and 8b were tested against five cancer cell lines related to the lung and liver subtypes. Moreover, 6f was examined on both cell cycle progression and apoptosis induction in HuH7 cancer cells. Furthermore, the in vivo antitumor activity of 6f was further assessed in female mice with solid Ehrlich carcinoma. In addition, molecular docking and molecular dynamics simulations were carried out. Collectively, 6f, 8a, and 8b could be considered potential new telomerase inhibitors to be subjected to further investigation and/or optimization.

2-Aminobenzothiazoles in anticancer drug design and discovery

Cancer is one of the major causes of mortality and morbidity worldwide. Substantial research efforts have been made to develop new chemical entities with improved anticancer efficacy. 2-Aminobenzothiazole is an important class of heterocycles containing one sulfur and two nitrogen atoms, which is associated with a broad spectrum of medical and pharmacological activities, including antitumor, antibacterial, antimalarial, anti-inflammatory, and antiviral activities. In recent years, an extraordinary collection of potent and low-toxicity 2-aminobenzothiazole compounds have been discovered as new anticancer agents. Herein, we provide a comprehensive review of this class of compounds based on their activities against tumor-related proteins, including tyrosine kinases (CSF1R, EGFR, VEGFR-2, FAK, and MET), serine/threonine kinases (Aurora, CDK, CK, RAF, and DYRK2), PI3K kinase, BCL-XL, HSP90, mutant p53 protein, DNA topoisomerase, HDAC, NSD1, LSD1, FTO, mPGES-1, SCD, hCA IX/XII, and CXCR. In addition, the anticancer potentials of 2-aminobenzothiazole-derived chelators and metal complexes are also described here. Moreover, the design strategies, mechanism of actions, structure-activity relationships (SAR) and more advanced stages of pre-clinical development of 2-aminobenzothiazoles as new anticancer agents are extensively reviewed in this article. Finally, the examples that 2-aminobenzothiazoles showcase an advantage over other heterocyclic systems are also highlighted.

Recent insights into antibacterial potential of benzothiazole derivatives

Antimicrobial resistance (AMR) is a worldwide concern among infectious diseases due to increased mortality, morbidity and treatment cost. According to WHO 2019 report, among the 32 antibiotics in the clinical trials, only six were classified as innovative and containing novel moiety. The remaining antibiotics from this list contain previously known moiety (WHO AMR 2019). Therefore, the development of novel antibiotics to control resistance problems is crucial. Benzothiazole derivatives are of great interest due to their wide range of biological activities and medicinal applications. Reported data indicated that benzothiazole derivatives displayed antibacterial activity by inhibiting the dihydroorotase, DNA gyrase, uridine diphosphate-n-acetyl enol pyruvyl glucosamine reductase (MurB), peptide deformylase, aldose reductase, casdihydrofolate reductase, enoyl acyl carrier protein reductase, dialkylglycine decarboxylase, dehydrosqualene synthase, dihydropteroate synthase and tyrosine kinase. The present review analyzed the synthesis, structure-activity relationship (SAR) and mechanism of action studies of benzothiazole derivatives as antibacterial agents reported by various research groups in the last five years (2018-2022). Different patents on the antimicrobial activity of benzothiazole derivatives have also been summarized. The finding of the present review will be beneficial for the researchers in the development of novel antibacterial molecules based on benzothiazole moiety.

Graphical Abstract

Development of certain aminoquinazoline scaffolds as potential multitarget anticancer agents with apoptotic and anti-proliferative effects: Design, synthesis and biological evaluation

Newly designed 4 - aminoquinazoline derivatives (5a-f, 6a, b, 7, 8, 9, 10a-c, 11a, b, 12a, b and 13a, b) have been synthesized and evaluated for their potential multitarget anticancer activities, apoptotic and anti-proliferative effects. Thereupon, in vitro cytotoxic activities of all the synthesized compounds were screened against NCI 60 human cancer cell lines (nine subpanels) at NCI, USA. Successfully, 2-morpholino-N-(quinazolin-4-yl) acetohydrazide 5e was granted an NSC code, owing to its significant potency and broad spectrum of activity against various cancer cell lines; leukemia K-562, non-small cell lung cancer NCI-H522 cells, colon cancer SW-620, melanoma LOX IMVI, MALME-3M, renal cancer RXF 393, ACHN and breast cancer MDA-MB231/ATCC (GI% = 99.6, 161, 126.03, 90.22, 174.47, 139.7, 191 and 97, respectively). Compound 5e showed the best inhibitory activity (GI₅₀ = 1.3 µM) against melanoma LOX IMVI, when tested at five doses against NCI 60 cell lines. Furthermore, compound 5e showed comparable EGFR and CDK2 inhibitory activity results (IC₅₀ = 0.093 ± 0.006 μM and 0.143 ± 0.008 μM, respectively) to those of lapatinib and ribociclib (IC₅₀ = 0.03 ± 0.002 μM and 0.067 ± 0.004 μM, respectively). Western blotting analysis of compound 5e against melanoma LOX IMVI marked out significant reduced EGFR and CDK2 protein expression percentages, up to 32.97% and 34.09%, respectively, if compared to lapatinib (31.18%) and ribociclib (29.66%). Moreover, compound 5e caused clear cell cycle arrests at S phase of renal UO-31 cells and at G1 phase of both breast cancer MCF7 and ovarian cancer IGROV1, associated with remarkable increase of DNA content of the controls. In accordance, it demonstrated promising anti- proliferative and apoptotic activities, showing a significant increase in total apoptotic percentages of renal cancer UO-31, breast cancer MCF7 and ovarian IGROV1 cancer cell lines, if compared to the control untreated cells (from 1.79% to 46.72%, 2.19% to 39.02% and 1.66 to 42.51%, respectively). Molecular modelling and dynamic simulation study results supported the main objectives of the present work.

Design and synthesis of new heterocyclic compounds containing 5-[(1H-1,2,4-triazol-1-yl)methyl]-3H-1,2,4-triazole-3-thione structure as potent hEGFR inhibitors

EGFR is one of the important mediators of the signaling cascade that determines key roles in various biological processes such as growth, differentiation, metabolism and apoptosis in the cell in response to external and internal stimuli. In recent years, it has been proven that although this enzyme activity is tightly regulated in normal cells, if the enzyme activity cannot be controlled, it can lead to malignancy. EGFR is also considered a prominent macromolecule in targeted cancer chemotherapy. For this purpose, a comprehensive modeling studies were conducted against EGFR protein and novel molecules containing 5-[(1H-1,2,4-triazol-1-yl)methyl]-3H-1,2,4-triazole-3-thione structure were suggested to be synthesized. Among the synthesized molecules, compounds 7c, 8c, 8f and 8g were determined to have significant IC50 values. Compound 8g was found to have the IC50 value closest to the very well-known EGFR inhibitor Gefitinib with its noncompetitive inhibition form. Ki value of compound 8g was calculated as 0.00232 µM.Communicated by Ramaswamy H. Sarma.

New Benzimidazole-, 1,2,4-Triazole-, and 1,3,5-Triazine-Based Derivatives as Potential EGFRWT and EGFRT790M Inhibitors: Microwave-Assisted Synthesis, Anticancer Evaluation, and Molecular Docking Study

A new series of benzimidazole, 1,2,4-triazole, and 1,3,5-triazine derivatives were designed and synthesized using a microwave irradiation synthetic approach utilizing 2-phenylacetyl isothiocyanate (1) as a key starting material. All the new analogues were evaluated as anticancer agents against a panel of cancer cell lines utilizing doxorubicin as a standard drug. Most of the tested derivatives exhibited selective cytotoxic activity against MCF-7 and A-549 cancer cell lines. Furthermore, the new target compounds 5, 6, and 7 as the most potent antiproliferative agents have been assessed as in vitro EGFR^WT and EGFR^T790M inhibitors compared to the reference drugs erlotinib and AZD9291. They represented more potent suppression activity against the mutated EGFR^T790M than the wild-type EGFR^WT. Moreover, the compounds 5, 6, and 7 down-regulated the oncogenic parameter p53 ubiquitination. A docking simulation of compound 6b was carried out to correlate its molecular structure with its significant EGFR inhibition potency and its possible binding interactions within the active site of EGFR^WT and the mutant EGFR^T790M.

A medicinal chemist's perspective towards structure activity relationship of heterocycle based anti-cancer agents

AIM

To describe structure activity relationship of heterocyclic derivatives with multi-targeted anticancer activity.

OBJECTIVES

With the following goals in mind, this review tries to describe significant recent advances in the medicinal chemistry of heterocycle-based compounds: (1) To shed light on recent literature focused on heterocyclic derivatives' anticancer potential; (2) To discuss recent advances in the medicinal chemistry of heterocyclic derivatives, as well as their biological implications for cancer eradication; (3) To summarise the comprehensive correlation of structure activity relationship (SAR) with pharmacological outcomes in cancer therapy.

BACKGROUND

Cancer remains one of the major serious health issues devastating the world today. Cancer is a complex disease in which improperly altered cells proliferate at an uncontrolled, rapid, and severe rate. Variables such as poor dietary habits, high stress, age, and smoking, can all contribute to the development of cancer. Cancer can affect almost any organ or tissue, although the brain, breast, liver, and colon are the most frequently affected organs. From several years, surgical operations and irradiation are in use along with chemotherapy as a primary treatment of cancer but still effective treatment of cancer remains a huge challenge. Chemotherapy is now one of the most effective strategies to eradicate cancer, although it has been shown to have a number of cytotoxic and unfavourable effects on normal cells. Despite all of these cancer treatments, there are several other targets for anticancer drugs. Cancer can be effectively eradicated by focusing on these targets, which include both cell-specific and receptor-specific targets such as tyrosine kinase receptors (TKIs). Heterocyclic scaffolds also have a variety of applications in drug development and are a common moiety in the pharmaceutical, agrochemical, and textile industries.

METHODS

The association between structural activity relationship data of many powerful compounds and their anticancer potential in vitro and in vivo has been studied. SAR of powerful heterocyclic compounds can also be generated using molecular docking simulations, as reported vastly in literature.

CONCLUSIONS

Heterocycles have a wide range of applications, from natural compounds to synthesised derivatives with powerful anticancer properties. To avoid cytotoxicity or unfavourable effects on normal mammalian cells due to a lack of selectivity towards the target site, as well as to reduce the occurrence of drug resistance, safer anticancer lead compounds with higher potency and lower cytotoxicity are needed. This review emphasizes on design and development of heterocyclic lead compounds with promising anticancer potential.

Epidermal growth factor receptor inhibitors as potential anticancer agents: An update of recent progress

Epidermal growth factor receptor (EGFR) is a vital intermediate in cell signaling pathway including cell proliferation, angiogenesis, apoptosis, and metastatic spread and also having four divergent members with similar structural features, such as EGFR (HER1/ErbB1), ErbB2 (HER2/neu), ErbB3 (HER3), and ErbB4 (HER4). Despite this, clinically exploited inhibitors of EGFR (including erlotinib, lapatinib, gefitinib, selumetinib, etc.) are not specific thus provoking unenviable adverse effects. Some of the paramount obstacles to generate and develop new lead molecules of EGFR inhibitors are drug resistance, mutation, and also selectivity which inspire medicinal chemists to generate novel chemotypes. The discovery of therapeutic agents that inhibit the precise stage in tumorous cells such as EGFR is one of the chief successful targets in many cancer therapies, including lung and breast cancers. This review aims to compile the various recent progressions (2016-2021) in the discovery and development of diverse epidermal growth factor receptor (EGFR) inhibitors belonging to distinct structural classes like pyrazoline, pyrazole, imidazole, pyrimidine, coumarin, benzothiazole, etc. We have summarized preclinical and clinical data, structure-activity relationships (SAR) containing mechanistic and in silico studies to provide proposals for the design and invention of new EGFR inhibitors with therapeutic significance. The detailed progress of the work in the field will provide inexorable scope for the development of novel drug candidates with greater selectivity and efficacy.

Advances in 2-substituted benzothiazole scaffold-based chemotherapeutic agents

Targeted therapy plays a pivotal role in cancer therapeutics by countering the drawbacks of conventional treatment like adverse events and drug resistance. Over the last decade, heterocyclic derivatives have received considerable attention as cytotoxic agents by modulating various signaling pathways. Benzothiazole is an important heterocyclic scaffold that has been explored for its therapeutic potential. Benzothiazole-based derivatives have emerged as potent inhibitors of enzymes such as EGFR, VEGFR, PI3K, topoisomerases, and thymidylate kinases. Several researchers have designed, synthesized, and evaluated benzothiazole scaffold-based enzyme inhibitors. Of these, several inhibitors have entered various phases of clinical trials. This review describes the recent advances and developments of benzothiazole architecture-based derivatives as potent anticancer agents.