Design and synthesis of DNA-intercalative naphthalimide-benzothiazole/cinnamide derivatives: cytotoxicity evaluation and topoisomerase-IIα inhibition

An Overview of Naphthylimide as Specific Scaffold for New Drug Discovery

Naphthylimides play a pivotal role as aromatic heterocyclic compounds, serving as the foundational structures for numerous pharmacologically significant drugs. These drugs encompass antibacterial, antifungal, anticancer, antimalarial, antiviral, anti-inflammatory, antithrombotic, and antiprotozoal agents. The planar and heteroaromatic characteristics of naphthylimides grant them a strong ability to intercalate into DNA. This intercalation property renders naphthylimide derivatives highly valuable for various biological activities. The advantageous pharmacological activity and ease of synthesis associated with naphthylimides and their derivatives provide significant benefits in the design and development of new compounds within this class. Currently, only a few such molecules are undergoing preclinical and clinical evaluations. In this paper, we have compiled the literature on naphthylimides reported by researchers from 2006 to 2024. Our focus lies on exploring the pharmacological activities of their analogues from a drug development and discovery perspective, while examining their structure-activity relationship and mechanisms of action.

In vitro anti-breast cancer study of hybrid cinnamic acid derivatives bearing 2-thiohydantoin moiety

Aim: To synthesize new hybrid cinnamic acids (10a, 10b and 11) and ester derivatives (7, 8 and 9) and investigate their anti-breast cancer activities.Materials & methods: Compounds 7-11 were evaluated (in vitro) for their cytotoxic activities against the MCF-7 cell line. A flow cytometry examination was performed. Protein levels of nuclear factor erythroid 2-related factor 2 (Nrf2), topoisomerase II and caspase-9 were measured by qRT-PCR. Molecular docking studies were conducted.Results: Several components were discovered to be active, mainly component 11, which induced arrest in the cell cycle at phase S, greatly decreased the expression of Nrf2 and topoisomerase II; and upregulated the expression of caspase-9.Conclusion: The newly thiohydantoin-cinnamic acid hybrids can contribute to creating promising candidates for cancer drugs.

Microwave-Assisted Ru(II)-Catalyzed Regioselective Methyl Acylation of 2-Arylbenzoazoles: Synthesis of Benzofuran Conjugates via C-H Activation/Annulation

An efficient Ru(II)-catalyzed C-H functionalization protocol for 2-arylbenzoazoles as the directing group and sulfoxonium ylide has been developed. Gratifyingly, concomitant annulation was observed when 3-(benzo[d]azol-2-yl) phenol was used, enabling the construction of benzofuran conjugates. Notably, the utilization of water as the solvent and an energy efficient approach makes the reaction greener, contributing to overall sustainability. This protocol exhibits excellent scalability up to the gram scale with a diverse array of substitutions. Furthermore, the mechanism was examined by ESI-MS, and photophysical studies were also performed.

Benzothiazole-based apoptosis inducers: A comprehensive overview and future prospective

Cancer has become a major concern in healthcare globally, and over time, incidences and prevalence of cancer are increasing. To counter this, a lot of anticancer drugs are approved and are in clinical use, playing a pivotal role in its treatment. Due to drug resistance and adverse effects, a continuous demand for novel, potent, and safe candidates to treat cancer is always there. Over the last few decades, various heterocyclic ring-based derivatives have been explored and reported in the literature. In this regard, benzothiazole scaffold-based compound emerged as the versatile ring for developing novel and safe anticancer candidates. In this article, we have reported various benzothiazole heterocyclic ring-based derivatives demonstrating potent antiproliferative activity by induction of apoptosis via an intrinsic pathway in a dose-dependent manner. These compounds also displayed inhibition of different enzymes, for example, Aurora kinase, epidermal growth factor receptor, vascular endothelial growth factor receptor, phosphoinositide kinases, DNA topoisomerase, and tubulin polymerases. This study focused on a comprehensive overview of antiproliferative activity, structure-activity relationship, apoptosis induction activity, and enzyme inhibition by benzothiazole-based compounds.

Synthesis, Characterization, Cytotoxicity, Cellular Imaging, Molecular Docking, and ADMET Studies of Piperazine-Linked 1,8-Naphthalimide-Arylsulfonyl Derivatives

To reduce the mortality and morbidity associated with cancer, new cancer theranostics are in high demand and are an emerging area of research. To achieve this goal, we report the synthesis and characterization of piperazine-linked 1,8-naphthalimide-arylsulfonyl derivatives (SA1-SA7). These compounds were synthesized in good yields following a two-step protocol and characterized using multiple analytical techniques. In vitro cytotoxicity and fluorescent cellular imaging of the compounds were assessed against non-cancerous fibroblast (3T3) and breast cancer (4T1) cell lines. Although the former study indicated the safe nature of the compounds (viability = 82-95% at 1 μg/mL), imaging studies revealed that the designed probes had good membrane permeability and could disperse in the whole cell cytoplasm. In silico studies, including molecular docking, molecular dynamics (MD) simulation, and ADME/Tox results, indicated that the compounds had the ability to target CAIX-expressing cancers. These findings suggest that piperazine-linked 1,8-naphthalimide-arylsulfonyl derivatives are potential candidates for cancer theranostics and a valuable backbone for future research.

Research Progress on Structure-Activity Relationship of 1,8-Naphthalimide DNA Chimeras Against Tumor

The development of 1,8-naphthalimide derivatives as cell probes, DNA targeting agents, and anti-tumor drugs is one of the research hotspots in the field of medicine. Naphthalimide compounds are a kind of DNA embedder, which can change the topological structure of DNA by embedding in the middle of DNA base pairs, and then affect the recognition and action of topoisomerase on DNA. Aminofide and mitonafide are the first 2 drugs to undergo clinical trials. They have good DNA insertion ability, can embed DNA double-stranded structure, and induce topoisomerase II to cut part of pBR322DNA, but not yet entered the market due to their toxicity. In this paper, the design and structure-activity relationship of mononaphthalimide and bisaphthalimide compounds were studied, and the relationship between the structure of naphthalimide and anti-tumor activity was analyzed and discussed. It was found that a variety of structural modifications were significant in improving anti-tumor activity and reducing toxicity.

AIEE activated Pyrene-Dansyl coupled FRET probe for discriminating detection of lethal Cu2+ and CN-: Bio-Imaging, DNA binding studies and prompt prognosis of Menke's disease

In present work a pyrene-dansyl dyad functionalized chemoreceptor, DPNS is unveiled towards ultrasensitive chromo-fluorogenic detection of heavy and transition metal ions (HTMs) like Cu2+ and pernicious CN-. It demonstrated distinct chromogenic responses; colorless to faint yellow (Cu2+), intense yellow (CN-) from contaminant aqueous sources. Cu2+ instigated alteration in DPNS fluorescence from feeble emission to sparkling green with LOD: 37.75 × 10-9 M, cyan emission for CN- having LOD 61.51 × 10-8M. In particular, chemical scaffold of DPNS consists of -C = N, O = S = O donor entitities that escalates overall polarity thereby providing an excellent binding pocket for simultaneous Cu2+ and CN- recognition with distinct photophysical signaling. Impressively, presence of two fluorophoric moieties triggers FRET, CHEF phenomenon. The conceivable host:guest interactive pathway is manifested by LMCT- FRET-PET-CHEF, C = N isomerization for Cu2+ and ICT-H-bonding for CN-. An exquisite experimental and theoretical corroboration further strengthened the recognition phenomenon. In addition owing to pyrene excimer formation, DPNS exhibits AIEE with increasing water fraction. Notably, DPNS could successfully undergo intracellular tracking of Cu2+ in Tecoma Stans, Peperomia Pellucida. DPNS•••Cu2+ adduct displayed significant intercalative DNA binding activity rationalized by spectral investigation, competitive EB binding, viscosity study. The overall findings, excellent properties endows DPNS a potential contender towards discriminative detection of Cu2+ and CN- like toxic industrial contaminants.

Prospects of Topoisomerase Inhibitors as Promising Anti-Cancer Agents

Topoisomerases are very important enzymes that regulate DNA topology and are vital for biological actions like DNA replication, transcription, and repair. The emergence and spread of cancer has been intimately associated with topoisomerase dysregulation. Topoisomerase inhibitors have consequently become potential anti-cancer medications because of their ability to obstruct the normal function of these enzymes, which leads to DNA damage and subsequently causes cell death. This review emphasizes the importance of topoisomerase inhibitors as marketed, clinical and preclinical anti-cancer medications. In the present review, various types of topoisomerase inhibitors and their mechanisms of action have been discussed. Topoisomerase I inhibitors, which include irinotecan and topotecan, are agents that interact with the DNA-topoisomerase I complex and avert resealing of the DNA. The accretion of DNA breaks leads to the inhibition of DNA replication and cell death. On the other hand, topoisomerase II inhibitors like etoposide and teniposide, function by cleaving the DNA-topoisomerase II complex thereby effectively impeding the release of double-strand DNA breaks. Moreover, the recent advances in exploring the therapeutic efficacy, toxicity, and MDR (multidrug resistance) issues of new topoisomerase inhibitors have been reviewed in the present review.

A review on the design, synthesis, and structure-activity relationships of benzothiazole derivatives against hypoxic tumors

There has been a growing body of studies on benzothiazoles and benzothiazole derivatives as strong and effective antitumor agents against lung, liver, pancreas, breast, and brain tumors. Due to highly proliferative nature of the tumor cells, the oxygen levels get lower than that of a normal tissue in the tumor microenvironment. This situation is called as hypoxia and has been associated with increased ability for carcinogenesis. For the drug design and development strategies, hypoxic nature of the tumor tissues has been exploited more aggressively. Hypoxia itself acts as a signal initiating system to activate the pathways that eventually lead to the spread of the tumor cells into the different tissues, increases the rate of DNA damage and eventually ends up with more mutation levels that may increase the drug resistance. As one of the major mediators of hypoxic response, hypoxia inducible factors (HIFs) has been shown to activate to angiogenesis, metastasis, apoptosis resistance, and many other protumorigenic responses in cancer development. In the current review, we will be discussing the design, synthesis and structure-activity relationships of benzothiazole derivatives against hypoxic tumors such lung, liver, pancreas, breast and brain as potential anticancer drug candidates. The focus points of the study will be the biology behind carcinogenesis and how hypoxia contributes to the process, recent studies on benzothiazole and its derivatives as anti-cancer agents against hypoxic cancers, conclusions and future perspectives. We believe that this review will be useful for the researchers in the field of drug design during their studies to generate novel benzothiazole-containing hybrids against hypoxic tumors with higher efficacies.

Thiazole and Related Heterocyclic Systems as Anticancer Agents: A Review on Synthetic Strategies, Mechanisms of Action and SAR Studies

Background:

Cancer is the second leading cause of death throughout the world. Many anticancer drugs are commercially available, but lack of selectivity, target specificity, cytotoxicity and development of resistance lead to serious side effects. There have been several experiments going on to develop compounds with minor or no side effects.

Objective:

This review mainly emphasizes synthetic strategies, SAR studies, and mechanism of action for thiazole, benzothiazole, and imidazothiazole containing compounds as anticancer agents.

Methods:

Recent literature related to thiazole and thiazole-related derivatives endowed with encouraging anticancer potential is reviewed. This review emphasizes contemporary strategies used for the synthesis of thiazole and related derivatives, mechanistic targets, and comprehensive structural activity relationship studies to provide perspective into the rational design of high-efficiency thiazole-based anticancer drug candidates.

Results:

Exhaustive literature survey indicated that thiazole derivatives are associated with properties of inducing apoptosis and disturbing tubulin assembly. Thiazoles are also associated with the inhibition of NFkB/mTOR/PI3K/AkT and regulation of estrogen-mediated activity. Furthermore, thiazole derivatives have been found to modulate critical targets such as topoisomerase and HDAC.

Conclusion:

Thiazole derivatives seem to be quite competent and act through various mechanisms. Some of the thiazole derivatives, such as compounds 29, 40, 62, and 74a with IC50 values of 0.05 μM, 0.00042 μM, 0.18 μM, and 0.67 μM, respectively not only have anticancer activity but they also have lower toxicity and better absorption. Therefore, some other similar compounds could be investigated to aid in the development of anticancer pharmacophores.

Combining structure-based and 3D QSAR pharmacophore models to discover diverse ligands against EGFR in oral cancer

Background: Epidermal growth factor receptor-tyrosine kinase (EGFR-TK) is a well-known hallmark of oral and oropharyngeal cancers, as its overexpression leads to poor prognosis and malignancy. The activating EGFR mutations (particularly T790M and L858R double mutant) are a major challenge causing drug resistance, especially in the treatment of oral cancers. Methodology: This paper is an effort to exploit both structure-based and ligand-based pharmacophore modeling to discover EGFR-TK inhibitors, which show inhibition of proliferation of erlotinib-resistant FaDu and Cal27 oral cancer cells. Interestingly, the hit compound H2 also showed an effect on the downstream glucose and lactate metabolism pathways. Conclusion: The results indicate the potential of H2 to be developed as an EGFR-based metabolic inhibitor for oral cancer treatment.

Expedition of sulfur-containing heterocyclic derivatives as cytotoxic agents in medicinal chemistry: A decade update

This review article proposes a comprehensive report of the design strategies engaged in the development of various sulfur-bearing cytotoxic agents. The outcomes of various studies depict that the sulfur heterocyclic framework is a fundamental structure in diverse synthetic analogs representing a myriad scope of therapeutic activities. A number of five-, six- and seven-membered sulfur-containing heterocyclic scaffolds, such as thiazoles, thiadiazoles, thiazolidinediones, thiophenes, thiopyrans, benzothiazoles, benzothiophenes, thienopyrimidines, simple and modified phenothiazines, and thiazepines have been discussed. The subsequent studies of the derivatives unveiled their cytotoxic effects through multiple mechanisms (viz. inhibition of tyrosine kinases, topoisomerase I and II, tubulin, COX, DNA synthesis, and PI3K/Akt and Raf/MEK/ERK signaling pathways), and several others. Thus, our concise illustration explains the design strategy and anticancer potential of these five- and six-membered sulfur-containing heterocyclic molecules along with a brief outline on seven-membered sulfur heterocycles. The thorough assessment of antiproliferative activities with the reference drug allows a proficient assessment of the structure-activity relationships (SARs) of the diversely synthesized molecules of the series.

Photochemical synthesis, intercalation with DNA and antitumor evaluation in vitro of benzo[d]thiazolo[3,2-a]quinolin-10-ium derivatives

A new anticancer benzo[d]thiazolo[3,2-a]quinolin-10-ium derivatives were synthesized and characterized. Anticancer evaluation in vitro against four cancer cell lines including adenocarcinomic human alveolar basal epithelial cells (A549), hepatocellular carcinoma (HepG2), prostate cancer (PC3) and breast cancer (MCF7) indicated that some of prepared compounds shows higher selectivity in comparison with doxorubicin. DNA interaction studies by optical, CD, NMR spectroscopies showed the high affinity of benzothiazole ligands towards the dsDNA. The ligand-DNA interaction occurs through the intercalation of benzo[d]thiazolo[3,2-a]quinolin-10-ium derivatives with nucleic acid. The investigation of formed ligand - DNA complexes by docking and molecular dynamic calculations was applied for analysis of the relationship between structure and anticancer activity. The results suggested that benzo[d]thiazolo[3,2-a]quinolin-10-ium derivatives might serve as a novel scaffold for the future development to new antitumor agents.

Yb/Chitosan Catalyzed Synthesis of Highly Substituted Piperidine Derivatives for Potential Nuclease Activity and DNA Binding Study

BACKGROUND

Herein, a new chitosan-supported ytterbium nano-catalyst has been prepared and used in a mild, efficient, and expeditious method for the synthesis of substituted piperidine derivatives via threecomponent condensation of substituted anilines, formaldehyde and different cyclic/acyclic active methylene compounds at room temperature.

METHODS

The catalyst was characterized by FTIR, XRD, SEM, EDX, TEM, ICP-AES and the stability of the catalyst was evaluated by TG analysis. The synthesized compound 3,3,11,11-Tetramethyl-15-(phenyl)-15- azadispiro[5.1.5.3]hexadecane-1,5,9,13-tetrone (3a) was explored for pBR322 DNA cleavage activity and genotoxicity. Further, the interaction of 3a with CT-DNA was investigated through UV-vis, fluorescence and viscosity.

RESULTS

The preparation of Yb/chitosan nano-catalyst was verified and the catalyst was found effective towards substituted piperidine formations with the catalyst reusability. Compound 3a was successfully tested for DNA cleavage activity. In addition, fluorescence results revealed that compound 3a interacted with DNA with a binding affinity of 4.84 x 10⁴ M^-1.

CONCLUSION

Our findings suggest that compounds bearing spiro-piperidine scaffold, synthesized using reusable nano-catalyst, could be effective biological agents.

Synthesis and in Vitro Cytotoxicity Evaluation of Phenanthrene Linked 2,4- Thiazolidinediones as Potential Anticancer Agents

OBJECTIVE

To synthesize a series of phenanthrene-thiazolidinedione hybrids and explore their cytotoxic potential against human cancer cell lines of A-549 (lung cancer), HCT-116 and HT-29 (colon cancer), MDA MB-231 (triple-negative breast cancer), BT-474 (breast cancer) and (mouse melanoma) B16F10 cells.

METHODS

A new series of phenanthrene-thiazolidinedione hybrids was synthesized via Knoevenagel condensation of phenanthrene-9-carbaldehyde and N-alkylated thiazolidinediones. The cytotoxicity (IC₅₀) of the synthesized compounds was determined by MTT assay. Apoptotic assays like (AO/EB) and DAPI staining, cell cycle analysis, JC-1 staining and Annexin V binding assay studies were performed for the most active compound (Z)- 3-(4-bromobenzyl)-5-((2,3,6,7-tetramethoxyphenanthren-9-yl)methylene)thiazolidine-2,4-dione (17b). Molecular docking, dynamics and evaluation of pharmacokinetic (ADME/T) properties were also carried out by using Schrödinger.

RESULTS AND DISCUSSION

From the series of tested compounds, 17b unveiled promising cytotoxic action with an IC₅₀ value of 0.985±0.02μM on HCT-116 human colon cancer cells. The treatment of HCT-116 cells with 17b demonstrated distinctive apoptotic morphology like shrinkage of cells, horseshoe-shaped nuclei formation and chromatin condensation. The flow-cytometry analysis revealed the G0/G1 phase cell cycle arrest in a dosedependent fashion. The AO/EB, DAPI, DCFDA, Annexin-V and JC-1 staining studies were performed in order to determine the effect of the compound on cell viability. Computational studies were performed by using Schrödinger to determine the stability of the ligand with the DNA.

CONCLUSION

The current study provides an insight into developing a series of phenanthrene thiazolidinedione derivatives as potential DNA interactive agents which might aid in colon cancer therapy.

Synthesis of Triphenylethylene-Naphthalimide Conjugates as topoisomerase-IIα inhibitor and HSA binder

A series of triphenylethylene-naphthalimide (TPE-naph) conjugates was synthesized by a molecular hybridization technique, and their anticancer activity was evaluated in vitro on 60 human cancer cell lines through their cytotoxicity. The ratios of E and Z isomers were determined on the basis of HPLC methodology and NMR spectroscopy. The structure-activity relationship for anticancer activity was deduced on the basis of the nature and bulkiness of the amine attached to the C-4 position of the naphthalene ring. Experimental and molecular modeling studies of the most active TPE-naph conjugate bearing a morpholinyl group showed that it was able to inhibit topoisomerase-II (TOPO-II) as a possible intracellular target. Moreover, the transportation behavior of TPE-naph conjugate towards human serum albumin (HSA) indicated efficient binding affinity. The steady-state and time-dependent fluorescent results suggested that this conjugate quenched HSA significantly through static as well as dynamic quenching. Thus, this report discloses the scope of triphenylethylene-naphthalimide (TPE-naph) conjugates as efficient anticancer agents.

Benzothiazole derivatives as anticancer agents

Benzothiazole (BTA) belongs to the heterocyclic class of bicyclic compounds. BTA derivatives possesses broad spectrum biological activities such as anticancer, antioxidant, anti-inflammatory, anti-tumour, antiviral, antibacterial, anti-proliferative, anti-diabetic, anti-convulsant, analgesic, anti-tubercular, antimalarial, anti-leishmanial, anti-histaminic and anti-fungal among others. The BTA scaffolds showed a crucial role in the inhibition of the metalloenzyme carbonic anhydrase (CA). In this review an extensive literature survey over the last decade discloses the role of BTA derivatives mainly as anticancer agents. Such compounds are effective against various types of cancer cell lines through a multitude of mechanisms, some of which are poorly studied or understood. The inhibition of tumour associated CAs by BTA derivatives is on the other hand better investigated and such compounds may serve as anticancer leads for the development of agents effective against hypoxic tumours.

Design and synthesis of thiadiazolo-carboxamide bridged β-carboline-indole hybrids: DNA intercalative topo-IIα inhibition with promising antiproliferative activity

The conjoining of salient pharmacophoric properties directing the development of prominent cytotoxic agents was executed by constructing thiadiazolo-carboxamide bridged β-carboline-indole hybrids. On the evaluation of in vitro cytotoxic potential, 12c exhibited prodigious cytotoxicity among the synthesized new molecules 12a-k, with an IC50 < 5 μM in all the tested cancer cell lines (A549, MDA-MB-231, BT-474, HCT-116, THP-1) and the best cytotoxic potential was expressed in lung cancer cell line (A549) with an IC50 value of 2.82 ± 0.10 μM. Besides, another compound 12a also displayed impressive cytotoxicity against A549 cell line (IC50: 3.00 ± 1.40 μM). Further target-based assay of these two compounds 12c and 12a revealed their potential as DNA intercalative topoisomerase-IIα inhibitors. Additionally, the antiproliferative activity of compound 12c was measured in A549 cells by traditional apoptosis assays revealing the nuclear, morphological alterations, and depolarization of membrane potential in mitochondria and externalization of phosphatidylserine in a concentration-dependent manner. Cell cycle analysis unveiled the G0/G1 phase inhibition and wound healing assay inferred the inhibition of in vitro cell migration by compound 12c in lung cancer cells. Remarkably, the safety profile of compound 12c was disclosed by screening against normal human lung epithelial cell line (BEAS-2B: IC50: 71.2 ± 7.95 μM) with a selectivity index range of 14.9-25.26. Moreover, Molecular modeling studies affirm the intercalative binding of compound 12c and 12a in the active pocket of topo-IIα. Furthermore, in silico prediction of physico-chemical parameters divulged the propitious drug-like properties of the synthesized derivatives.

Development of β-carboline-benzothiazole hybrids via carboxamide formation as cytotoxic agents: DNA intercalative topoisomerase IIα inhibition and apoptosis induction

In quest of promising anticancer agents, the pharmacophores of natural (β-carboline) and synthetic origin (benzothiazole) were adjoined by a carboxamide bridge and three-point diversification was accomplished. The in vitro cytotoxic ability of the compounds was established on adherent and suspension human cancer cell lines and compounds 8u and 8f advanced as pre-eminent molecules with IC₅₀ values of 1.46 and 1.81 μM respectively in A549 cell line. The cytospecificity was entrenched for potent compounds 8u and 8f by evaluating against normal human lung epithelial cells and selectivity index was calculated. Furthermore, EtBr displacement, relative viscosity and gel-based topoisomerase II target assays unveiled the intercalative topo-II inhibitory capability and DNA binding studies (absorbance) revealed the dissociation constant (K_d) for compounds 8u and 8f as 98 and 103 μM respectively. Additionally, cell-based flow cytometric assays like Annexin-V/PI dual staining aids in the quantification of apoptosis induced and JC-1 staining disclosed the depolarization of mitochondrial membrane potential by compound 8u in A549 cells in a dose-dependent manner. Moreover, wound healing assay established the inhibition of in vitro cell migration by compound 8u on A549 cells. In addition, molecular docking studies proved the binding of compounds 8u and 8f in the active site of DNA complexed with topo IIα and stabilized by interactions with DNA base pairs and amino acid residues. Remarkably, the compounds 8u and 8f follow Lipinski's rule of five and are in the recommended range for Jorgensen's rule of three with a minimal violation and other pharmacokinetic parameters revealing druggability of the synthesized hybrids.

Synthesis and biological evaluation of substituted N-(2-(1H-benzo[d]imidazol-2-yl)phenyl)cinnamides as tubulin polymerization inhibitors

A new series of N-(2-(1H-benzo[d]imidazol-2-yl)phenyl) cinnamides was prepared and evaluated for their in vitro cytotoxic activity using various cancer cell lines viz. A549 (human non-small cell lung cancer), MDA-MB-231 (human triple negative breast cancer), B16-F10 (mouse melanoma), BT-474 (human breast cancer), and 4 T1 (mouse triple negative breast cancer). In the series of tested compounds, 12h showed potent cytotoxic activity against non-small cell lung cancer cell line with IC₅₀ value of 0.29 ± 0.02 µM. The cytoxicity of most potent compound 12h was also tested on NRK-52E (normal rat kidney epithelial cell line) and showed less cytotoxicity compared to cancer cells. Tubulin polymerization assay indicated that the compound 12h was able to impede the cell division by inhibiting tubulin polymerization. Moreover, molecular docking study also suggested the binding of 12h at the colchicine-binding site of the tubulin protein. Cell cycle analysis revealed that the compound 12h arrests G2/M phase. In addition, 12h induced apoptosis in A549 cell lines was evaluated by various staining studies like acridine orange, DAPI, analysis of mitochondrial membrane potential, annexin V-FITC, and DCFDA assays.

A novel naphthalimide that selectively targets breast cancer via the arylhydrocarbon receptor pathway

We report that the naphthalimide analogue 2-(2-aminophenyl)-1H-benzo[de]isoquinoline-1,3(2H)-dione (NAP-6) is a highly potent and selective breast cancer targeting molecule. These effects are mediated via the aryl hydrocarbon receptor (AHR) pathway and the subsequent induction of CYP1 metabolising monooxygenases in breast cancer cell line models. Indeed the triple negative breast cancer cell line MDA-MB-468 with a GI₅₀ value of 100 nM is greater than 500-fold more sensitive to NAP-6 compared with other tumour derived cell models. Within 1 h exposure of these cells to NAP-6, CYP1A1 expression increases 25-fold, rising to 250-fold by 24 h. A smaller concurrent increase in CYP1A2 and CYP1B1 is also observed. Within 24 h these cells present with DNA damage as evident by enhanced H2AXγ expression, cell cycle checkpoint activation via increased CHK2 expression, S-phase cell cycle arrest and cell death. Specific small molecule inhibitors of the AHR and CYP1 family ameliorate these events. A positive luciferase reporter assay for NAP-6 induced XRE binding further confirms the role of the AHR in this phenomenon. Non-sensitive cell lines fail to show these biological effects. For the first time we identify 2-(2-aminophenyl)-1H-benzo[de]isoquinoline-1,3(2H)-dione as a new AHR ligand that selectively targets breast cancer.

A Review on Anticancer Potentials of Benzothiazole Derivatives

Benzothiazole is an organic compound bearing a heterocyclic nucleus (thiazole) which imparts a broad spectrum of biological activities to it. The significant and potent activity of benzothiazole moiety influenced distinctively by nature and position of substitutions. This review summarizes the effect of various substituents in recent trends and approaches to design and develop novel benzothiazole derivatives for anticancer potential in different cell lines by interpreting the Structure- Activity Relationship (SAR) and mechanism of action of a wide range of derivatives. The list of derivatives is categorized into different groups and reviewed for their anticancer activity. The structure-activity relationship for the various derivatives revealed an excellent understanding of benzothiazole moiety in the field of cancer therapy against different cancer cell line. Data obtained from the various articles showed the potential effect of benzothiazole moiety and its derivatives to produce the peculiar and significant lead compound. The important anticancer mechanisms found are tyrosine kinase inhibition, topoisomerase inhibition and induction of apoptosis by Reactive Oxygen Species (ROS) activation. Therefore, the design and development of novel benzothiazole have broad scope in cancer chemotherapy.

Benzoxazines as new human topoisomerase I inhibitors and potential poisons

BACKGROUND

The numbers of topoisomerase I targeted drugs on the market are very limited although they are used clinically for treatment of solid tumors. Hence, studies about finding new chemical structures which specifically target topoisomerase I are still remarkable.

OBJECTIVES

In this present study, we tested previously synthesized 3,4-dihydro-2H-1,4-benzoxazin-3-one derivatives to reveal their human DNA topoisomerase I inhibitory potentials.

METHODS

We investigated inhibitory activities of 3,4-dihydro-2H-1,4-benzoxazin-3-one derivatives on human topoisomerase I by relaxation assay to clarify inhibition mechanisms of effective derivatives with EMSA and T4 DNA ligase based intercalation assay. With SAR study, it was tried to find out effective groups in the ring system.

RESULTS

While 10 compounds showed catalytic inhibitory activity, 8 compounds were found to be potential topoisomerase poisons. 4 of them also exhibited both activities. 2-hydroxy-3,4-dihydro-2H-1,4-benzoxazin-3-one (BONC-001) was the most effective catalytic inhibitor (IC₅₀:8.34 mM) and ethyl 6-chloro-4-methyl-3-oxo-3,4-dihydro-2H-1,4-benzoxazin-2-acetate (BONC-013) was the strongest potential poison (IC₅₀:0.0006 mM). BONC-013 was much more poisonous than camptothecin (IC₅₀:0.034 mM). Intercalation assay showed that BONC-013 was not an intercalator and BONC-001 most probably prevented enzyme-substrate binding in an unknown way. Another important result of this study was that OH group instead of ethoxycarbonylmethyl group at R position of benzoxazine ring was important for hTopo I catalytic inhibition while the attachment of a methyl group of R1 position at R₂ position were play a role for increasing of its poisonous effect.

CONCLUSION

As a result, we presented new DNA topoisomerase I inhibitors which might serve novel constructs for future anticancer agent designs. Graphical abstract.