Amino alcohol acrylonitriles as broad spectrum and tumour selective cytotoxic agents

Next-generation of BBQ analogues that selectively target breast cancer

We previously reported on the interaction of 10-chloro-7H-benzo[de]benzo[4,5]imidazo[2,1-a]isoquinolin-7-one (10-Cl-BBQ) with the Aryl hydrocarbon Receptor (AhR) and selective growth inhibition in breast cancer cell lines. We now report on a library of BBQ analogues with substituents on the phenyl and naphthyl rings for biological screening. Herein, we show that absence of the phenyl Cl of 10-Cl-BBQ to produce the simple BBQ molecule substantially enhanced the growth inhibitory effect with GI50 values of 0.001-2.1 μM in select breast cancer cell lines MCF-7, T47D, ZR-75-1, SKBR3, MDA-MB-468, BT20, BT474 cells, while having modest effects of 2.1-7 μM in other cell lines including HT29, U87, SJ-G2, A2780, DU145, BE2-C, MIA, MDA-MB-231 or normal breast cells, MCF10A (3.2 μM). The most potent growth inhibitory effect of BBQ was observed in the triple negative cell line, MDA-MB-468 with a GI50 value of 0.001 μM, presenting a 3,200-fold greater response than in the normal MCF10A breast cells. Additions of Cl, CH3, CN to the phenyl ring and ring expansion from benzoimidazole to dihydroquinazoline hindered the growth inhibitory potency of the BBQ analogues by blocking potential sites of CYP1 oxidative metabolism, while addition of Cl or NO2 to the naphthyl rings restored potency. In a cell-based reporter assay all analogues induced 1.2 to 10-fold AhR transcription activation. Gene expression analysis confirmed the induction of CYP1 oxygenases by BBQ. The CYP1 inhibitor α-naphthoflavone, and the SULT1A1 inhibitor quercetin significantly reduced the growth inhibitory effect of BBQ, confirming the importance of both phase I and II metabolic activation for growth inhibition. Conventional molecular modelling/docking revealed no significant differences between the binding poses of the most and least active analogues. More detailed DFT analysis at the DSD-PBEP86/Def-TZVPP level of theory could not identify significant geometric or electronic changes which would account for this varied AhR activation. Generation of Fukui functions at the same level of theory showed that CYP1 metabolism will primarily occur at the phenyl head group of the analogues, and substituents within this ring lead to lower cytotoxicity.

A pyrazolopyridine as a novel AhR signaling activator with anti-breast cancer properties in vitro and in vivo

Breast cancer is one of the main causes of malignancy-related deaths globally and has a significant impact on women's quality of life. Despite significant therapeutic advances, there is a medical need for targeted therapies in breast cancer. Aryl hydrocarbon receptor (AhR), a ligand-dependent transcription factor mediates responses to environment stimuli, is emerging as a unique pleiotropic target. Herein, a combined molecular simulation and in vitro investigations identified 3-(3-fluorophenyl)-1H-pyrazolo[3,4-b]pyridine (3FPP) as a novel AhR ligand in T47D and MDA-MB-231 breast cancer cells. Its agonistic effects induced formation of the AhR-AhR nuclear translocator (Arnt) heterodimer and prompted its binding to the penta-nucleotide sequence, called xenobiotic-responsive element (XRE) motif. Moreover, 3FPP augmented the promoter-driven luciferase activities and expression of AhR-regulated genes encoding cytochrome P450 1A1 (CYP1A1) and microRNA (miR)-212/132 cluster. It reduced cell viability, migration, and invasion of both cell lines through AhR signaling. These anticancer properties were concomitant with reduced levels of B-cell lymphoma 2 (BCL-2), SRY-related HMG-box4 (SOX4), snail family zinc finger 2 (SNAI2), and cadherin 2 (CDH2). In vivo, 3FPP suppressed tumor growth and activated AhR signaling in an orthotopic mouse model. In conclusion, our results introduce the fused pyrazolopyridine 3FPP as a novel AhR agonist with AhR-specific anti-breast cancer potential in vitro and in vivo.

Novel piperazine-1,2,3-triazole leads for the potential treatment of pancreatic cancer

From lead 1, (N-(4-((4-(3-(4-(3-methoxyphenyl)-1H-1,2,3-triazol-1-yl)propyl)piperazin-1-yl)sulfonyl)-phenyl)acetamide), a S100A2-p53 protein-protein interaction inhibitor based on an in silico modelling driven hypothesis, four focused libraries were designed and synthesised. Growth inhibition screening was performed against 16 human cancer cell lines including the pancreatic cell lines MiaPaCa2, BxPC3, AsPC-1, Capan-2, HPAC, PANC-1 and the drug resistant CFPAC1. Modification of 1's phenylacetamide moiety, gave Library 1 with only modest pancreatic cancer activity. Modification of the 3-OCH3Ph moiety (Library 2) gave 4-CH3 (26), 4-CH2CH3 (27), 4-CF3 (31) and 4-NO2 (32) with sterically bulky groups more active. A 4-CF3 acetamide replacement enhanced cytotoxicity (Library 3). The 4-C(CH3)336 resulted in a predicted steric clash in the S100A2-p53 binding groove, with a potency decrease. Alkyl moieties afforded more potent analogues, 34 (4-CH3) and 35 (CH2CH3), a trend evident against pancreatic cancer: GI50 3.7 (35; BxPC-3) to 18 (40; AsPC-1) μM. Library 4 analogues with a 2-CF3 and 3-CF3 benzenesulfonamide moiety were less active than the corresponding Library 3 analogues. Two additional analogues were designed: 51 (4-CF3; 4-OCH3) and 52 (4-CF3; 2-OCH3) revealed 52 to be 10-20 fold more active than 51, against the pancreatic cancer cell lines examined with sub-micromolar GI50 values 0.43 (HPAC) to 0.61 μM (PANC-1). MOE calculated binding scores for each pose are also consistent with the observed biological activity with 52. The obtained SAR data is consistent with the proposed interaction within the S100A2-p53 bonding groove.

Aryl Hydrocarbon Receptor as an Anticancer Target: An Overview of Ten Years Odyssey

Aryl hydrocarbon receptor (AhR), a ligand-activated transcription factor belonging to the basic helix-loop-helix (bHLH)/per-Arnt-sim (PAS) superfamily, is traditionally known to mediate xenobiotic metabolism. It is activated by structurally diverse agonistic ligands and regulates complicated transcriptional processes through its canonical and non-canonical pathways in normal and malignant cells. Different classes of AhR ligands have been evaluated as anticancer agents in different cancer cells and exhibit efficiency, which has thrust AhR into the limelight as a promising molecular target. There is strong evidence demonstrating the anticancer potential of exogenous AhR agonists including synthetic, pharmaceutical, and natural compounds. In contrast, several reports have indicated inhibition of AhR activity by antagonistic ligands as a potential therapeutic strategy. Interestingly, similar AhR ligands exert variable anticancer or cancer-promoting potential in a cell- and tissue-specific mode of action. Recently, ligand-mediated modulation of AhR signaling pathways and the associated tumor microenvironment is emerging as a potential approach for developing cancer immunotherapeutic drugs. This article reviews advances of AhR in cancer research covering publication from 2012 to early 2023. It summarizes the therapeutic potential of various AhR ligands with an emphasis on exogenous ligands. It also sheds light on recent immunotherapeutic strategies involving AhR.

2-{[4-(4-Bromophenyl)piperazin-1-yl)]methyl}-4-(3-chlorophenyl)-5-(4-methoxyphenyl)-2,4-dihydro-3H-1,2,4-triazole-3-thione

The novel compound 2-{[4-(4-bromophenyl)piperazin-1-yl)]methyl}-4-(3-chlorophenyl-5-(4-methoxyphenyl)-2,4-dihydro-3H-1,2,4-triazole-3-thione is obtained in good yield via a three-step protocol. The product’s structure is assigned by HRMS, IR, 1H and 13C NMR experiments.

Aryl acrylonitriles synthesis enabled by palladium-catalyzed α-alkenylation of arylacetonitriles with vinyl halides/triflates

Aryl acrylonitriles are an important subclass of acrylonitriles in the medicinal chemistry and pharmaceutical industry. Herein, an efficient synthesis of aryl acrylonitrile derivatives using a Palladium/NIXANTPHOS-based catalyst system was developed. This approach furnishes a variety of substituted and functionalized aryl acrylonitriles (up to 95% yield). The scalability of the transformation and the synthetic versatility of aryl acrylonitrile were demonstrated.

The Role of the Aryl Hydrocarbon Receptor (AhR) and Its Ligands in Breast Cancer

Breast cancer is a complex disease which is defined by numerous cellular and molecular markers that can be used to develop more targeted and successful therapies. The aryl hydrocarbon receptor (AhR) is overexpressed in many breast tumor sub-types, including estrogen receptor -positive (ER+) tumors; however, the prognostic value of the AhR for breast cancer patient survival is not consistent between studies. Moreover, the functional role of the AhR in various breast cancer cell lines is also variable and exhibits both tumor promoter- and tumor suppressor- like activity and the AhR is expressed in both ER-positive and ER-negative cells/tumors. There is strong evidence demonstrating inhibitory AhR-Rα crosstalk where various AhR ligands induce ER degradation. It has also been reported that different structural classes of AhR ligands, including halogenated aromatics, polynuclear aromatics, synthetic drugs and other pharmaceuticals, health promoting phytochemical-derived natural products and endogenous AhR-active compounds inhibit one or more of breast cancer cell proliferation, survival, migration/invasion, and metastasis. AhR-dependent mechanisms for the inhibition of breast cancer by AhR agonists are variable and include the downregulation of multiple genes/gene products such as CXCR4, MMPs, CXCL12, SOX4 and the modulation of microRNA levels. Some AhR ligands, such as aminoflavone, have been investigated in clinical trials for their anticancer activity against breast cancer. In contrast, several publications have reported that AhR agonists and antagonists enhance and inhibit mammary carcinogenesis, respectively, and differences between the anticancer activities of AhR agonists in breast cancer may be due in part to cell context and ligand structure. However, there are reports showing that the same AhR ligand in the same breast cancer cell line gives opposite results. These differences need to be resolved in order to further develop and take advantage of promising agents that inhibit mammary carcinogenesis by targeting the AhR.

Amino Alcohols as Potential Antibiotic and Antifungal Leads

Five focused compound libraries (forty-nine compounds), based on prior studies in our laboratory were synthesized and screened for antibiotic and anti-fungal activity against S. aureus, E. coli, K. pneumoniae, P. aeruginosa, A. baumannii, C. albicans and C. neoformans. Low levels of activity, at the initial screening concentration of 32 μg/mL, were noted with analogues of (Z)-2-(3,4-dichlorophenyl)-3-phenylacrylonitriles which made up the first two focused libraries produced. The most promising analogues possessing additional substituents on the terminal aromatic ring of the synthesised acrylonitriles. Modifications of the terminal aromatic moiety were explored through epoxide installation flowed by flow chemistry mediated ring opening aminolysis with discreet sets of amines to the corresponding amino alcohols. Three new focused libraries were developed from substituted anilines, cyclic amines, and phenyl linked heterocyclic amines. The aniline-based compounds were inactive against the bacterial and fungal lines screened. The introduction of a cyclic, such as piperidine, piperazine, or morpholine, showed >50% inhibition when evaluated at 32 μg/mL compound concentration against methicillin-resistant Staphylococcus aureus. Examination of the terminal aromatic substituent via oxirane aminolysis allowed for the synthesis of three new focused libraries of afforded amino alcohols. Aromatic substituted piperidine or piperazine switched library activity from antibacterial to anti-fungal activity with ((Z)-2-(3,4-dichlorophenyl)-3-(4-(2-hydroxy-3-(4-methylpiperazin-1-yl)propoxy)phenyl)acrylonitrile), ((Z)-2-(3,4-dichlorophenyl)-3-(4-(2-hydroxy-3-(4-(4-hydroxyphenyl)piperazin-1-yl)propoxy)-phenyl)acrylonitrile) and ((Z)-3-(4-(3-(4-cyclohexylpiperazin-1-yl)-2-hydroxypropoxy)-phenyl)-2-(3,4-dichlorophenyl)-acrylonitrile) showing >95% inhibition of Cryptococcus neoformans var. grubii H99 growth at 32 μg/mL. While (Z)-3-(4-(3-(cyclohexylamino)-2-hydroxypropoxy)phenyl)-2-(3,4-dichlorophenyl)-acrylonitrile, (S,Z)-2-(3,4-dichlorophenyl)-3-(4-(2-hydroxy-3-(piperidin-1-yl)propoxy)phenyl)acrylonitrile, (R,Z)-2-(3,4-dichlorophenyl)-3-(4-(2-hydroxy-3-(piperidin-1-yl)propoxy)phenyl)acrylonitrile, (Z)-2-(3,4-dichlorophenyl)-3-(4-(2-hydroxy-3-(D-11-piperidin-1-yl)propoxy)phenyl)-acrylonitrile, and (Z)-3-(4-(3-(4-cyclohexylpiperazin-1-yl)-2-hydroxypropoxy)-phenyl)-2-(3,4-dichlorophenyl)-acrylonitrile 32 μg/mL against Staphylococcus aureus.