Anti-cancer activity of a new dihydropyridine derivative, VdiE-2N, in head and neck squamous cell carcinoma

Two-Dimensional Cu(II)-MOF with Lewis Acid-Base Bifunctional Sites for Chemical Fixation of CO2 and Bioactive 1,4-DHP Synthesis via Hantzsch Condensation

Five- and six-membered heterocycles containing nitrogen or oxygen have been considered as privileged scaffolds in organic chemistry and the chemical industry because of their usage in high-value commodities. Herein, we report a two-dimensional (2D) Cu(II)-based MOF catalyst, IITKGP-40, via the strategic employment of ample Lewis acid-base bifunctional sites (open metal nodes and free pyrazine moieties) along the pore wall. IITKGP-40 could convert toxic CO2 to cyclic carbonates in an atom-economical manner under solvent-free conditions and aromatic aldehyde to bioactive 1,4-DHPs via Hantzsch condensation. Exceptional catalytic performance (99%) and turnover number under mild reaction conditions for CO2 fixation using sterically hindered styrene oxide, and good-to-excellent yields for a wide range of aromatic aldehydes toward 1,4-dihydropyridines (1,4-DHPs) make IITKGP-40 promising as a multipurpose heterogeneous catalyst. Moreover, to demonstrate the practical utility of the catalyst, two biologically important drug molecules, diludine and nitrendipine analogue, have also been synthesized. IITKGP-40 is recyclable for at least three consecutive runs without significant loss of activity, making it promising for real-time applications.

Accumulation of sphingosine kinase 2 protein induces malignant transformation in oral keratinocytes associated with stemness, autophagy, senescence, and proliferation

Sphingosine-1-phosphate (S1P) signaling has been widely explored as a therapeutic target in cancer. Sphingosine kinase 2 (SK2), one of the kinases that phosphorylate sphingosine, has a cell type and cell location-dependent mechanism of action, so the ability of SK2 to induce cell cycle arrest, apoptosis, proliferation, and survival is strongly influenced by the cell-context. In contrast to SK1, which is widely studied in different types of cancer, including head and neck cancer, the role of SK2 in the development and progression of oral cancer is still poorly understood. In order to elucidate SK2 role in oral cancer, we performed the overexpression of SK2 in non-tumor oral keratinocyte cell (NOK SK2) and in oral squamous cell carcinoma (HN12 SK2), and RNA interference for SK2 in another oral squamous cell carcinoma (HN13 shSK2). In our study we demonstrate for the first time that accumulation of SK2 can be a starting point for oncogenesis and transforms a non-tumor oral keratinocyte (NOK-SI) into highly aggressive tumor cells, even acting on cell plasticity. Furthermore, in oral metastatic cell line (HN12), SK2 contributed even more to the tumorigenesis, inducing proliferation and tumor growth. Our work reveals the intriguing role of SK2 as an oral tumor promoter and regulator of different pathways and cellular processes.

Synthesis and cytotoxicity evaluation of novel 1,8-acridinedione derivatives bearing phthalimide moiety as potential antitumor agents

In this study, we aimed to develop hybrid antitumor compounds by synthesizing and characterizing novel N-substituted acrididine-1,8-dione derivatives, designed as hybrids of phthalimide and acridine-1,8-diones. We employed a three-step synthetic strategy and characterized all compounds using IR, 1H NMR, 13C NMR, and LC-MS. The cytotoxicity and antitumor activity of five compounds (8c, 8f, 8h, 8i, and 8L) against four cancer cell lines (H460, A431, A549, and MDA-MB-231) compared to human skin fibroblast cells were evaluated. Among the synthesized compounds, compound 8f showed promising activity against skin and lung cancers, with favorable IC50 values and selectivity index. The relative changes in mRNA expression levels of four key genes (p53, TOP2B, p38, and EGFR) in A431 cells treated with the five synthesized compounds (8c, 8f, 8h, 8i, and 8L) were also investigated. Additionally, molecular docking studies revealed that compound 8f exhibited high binding affinity with TOP2B, p38, p53, and EGFR, suggesting its potential as a targeted anticancer therapy. The results obtained indicate that N-substituted acrididine-1,8-dione derivatives have the potential to be developed as novel antitumor agents with a dual mechanism of action, and compound 8f is a promising candidate for further investigation.

Synthesis of 4-Alkylated 1,4-Dihydropyridines: Fe(II)-Mediated Oxidative Cascade Cyclization Reaction of Cyclic Ethers with Enaminones

Syntheses of highly functionalized 4-alkylated 1,4-dihydropyridines (1,4-DHPs) from cyclic ethers and enaminones via iron(II)-mediated oxidative free radical cascade C(sp3)-H bond functionalization/C(sp3)-O bond cleavage/cyclization reaction have been first developed. This novel synthetic strategy offers an alternative method for the construction of 1,4-DHPs by using esters as the C4 sources, as well as expands the application of ethers in heterocycle synthesis.

3-Methyl 5-{3-[(4-Methylbenzenesulfonyl)oxy]propyl} 4-(2,3-Dichlorophenyl)-2,6-dimethyl-1,4-dihydropyridine-3,5-dicarboxylate

The 1,4-dihydropyridine is a ubiquitous scaffold employed not only in medicinal chemistry but also in organic synthesis, given its ability to act as a hydrogen transfer reagent, thus emulating NAD(P)H reducing agents. In this work, we describe the synthesis of 3-methyl 5-{3-[(4-methylbenzenesulfonyl)oxy]propyl} 4-(2,3-dichlorophenyl)-2,6-dimethyl-1,4-dihydropyridine-3,5-dicarboxylate as scaffold, which enables downstream derivatization towards new 1,4-dihydropyridine molecules. Inspired by the literature, a new two-step synthesis was planned that involved: (i) synthesis of a silylated 1,4-dihydropyridine derivative and (ii) deprotection and tosylation in one step using tosyl fluoride.

Highly Efficient Electrocarboxylation Method to Synthesize Novel Acid Derivatives of 1,4-Dihydropyridines and to Study Their Antimicrobial Activity

1,4-Dihydropyridines (1,4-DHPs) hold a top-notch position in the pharmaceutical world due to a broader spectrum of applications, whereas the carboxylic moiety has been an integral part of the physiological world, effective food preservatives, and antimicrobial agents. Seeking the enormous potential and applications of these two classes, we worked to combine these to synthesize 2,2'-[3,5-bis(ethoxycarbonyl)-4-phenyl-1,4-dihydropyridine-2,6-diyl]diacetic acid the novel dicarboxylic derivatives of 1,4-DHP (9a-k) achieved via the electro-carboxylation of tetrasubstituted-1,4-dihydropyridines (8a-k) derivatives using Mg-Pt electrodes in an undivided cell. The targeted compounds were established by ¹H, ¹³C NMR, IR, and ESI-MS. Further, the synthesized compounds show excellent resistance against various microbes and the activity increased 2-3 folds after the introduction of acid groups. Compound 9b (against E. coli, S. aureus, B. subtilis, A. niger, and P. glabrum), 9d (against E. coli, K. pneumonia, S. aureus, A. janus, and F. oxysporum), 9f (against E. coli and P. fluorescens), and 9k (against F. oxysporum and P. glabrum) were found to be highly active at 4 μg/mL with reference to standard amoxicillin and fluconazole. Further, the present synthetic protocol would open new gates for other researchers to develop new molecules by bioisosteres of these substrates.

5-Oxo-hexahydroquinoline and 5-oxo-tetrahydrocyclopentapyridine derivatives as promising antiproliferative agents with potential apoptosis-inducing capacity

Discovery of novel anticancer agents is of crucial importance to expand the therapeutic options for cancer patients. In this study, a series of 49 5-oxo-hexahydroquinoline and 5-oxo-tetrahydrocyclopentapyridine analogs, containing different pyridine alkyl carboxylates at C₃ and various aliphatic, aromatic, and heteroaromatic substitutions at the C₄ position of the central core, were synthesized. The target compounds were tested for antiproliferative effect against three human cancer cell lines including MOLT-4 (acute lymphoblastic leukemia), K562 (chronic myelogenous leukemia), and MCF-7 (breast adenocarcinoma) by MTT assay, and the effect of the most potent derivatives on cell cycle was evaluated by RNase/propidium iodide (PI) flow cytometric assay. Generally, 5-oxo-hexahydroquinoline derivatives (E series) possessed superior antiproliferative activities compared to their 5-oxo-tetrahydrocyclopentapyridine counterparts (F series). 5-Oxo-hexahydroquinoline compounds bearing 2-pyridyl propyl carboxylate (group D) and 3-pyridyl propyl carboxylate (group E) were better antiproliferative agents than those bearing other pyridyl alkyl carboxylates. Five best compounds with IC₅₀ values in the range of 9.5-22.9 µM against MOLT-4 cells were selected for cell-cycle analysis, which revealed that derivatives D5, E3, and E5 with 2,3-dichlorophenyl, 3-nitrophenyl, and 2-nitrophenyl substitutions at C₄ position, respectively, may induce apoptosis in MOLT-4 cells. Molecular docking analysis, which was employed to make some predictions on the interaction of the most active derivatives with the binding site of Bcl-2 and Bcl-xL proteins, suggested that the compounds may be well accommodated within the binding sites of these anti-apoptotic proteins via hydrogen-bonding and hydrophobic interactions. The findings of this study present 5-oxo-hexahydroquinoline derivatives as antiproliferative agents with potential apoptosis-inducing ability in cancer cells.

Exploring the therapeutic potential of mitochondrial uncouplers in cancer

BACKGROUND

Mitochondrial uncouplers are well-known for their ability to treat a myriad of metabolic diseases, including obesity and fatty liver diseases. However, for many years now, mitochondrial uncouplers have also been evaluated in diverse models of cancer in vitro and in vivo. Furthermore, some mitochondrial uncouplers are now in clinical trials for cancer, although none have yet been approved for the treatment of cancer.

SCOPE OF REVIEW

In this review we summarise published studies in which mitochondrial uncouplers have been investigated as an anti-cancer therapy in preclinical models. In many cases, mitochondrial uncouplers show strong anti-cancer effects both as single agents, and in combination therapies, and some are more toxic to cancer cells than normal cells. Furthermore, the mitochondrial uncoupling mechanism of action in cancer cells has been described in detail, with consistencies and inconsistencies between different structural classes of uncouplers. For example, many mitochondrial uncouplers decrease ATP levels and disrupt key metabolic signalling pathways such as AMPK/mTOR but have different effects on reactive oxygen species (ROS) production. Many of these effects oppose aberrant phenotypes common in cancer cells that ultimately result in cell death. We also highlight several gaps in knowledge that need to be addressed before we have a clear direction and strategy for applying mitochondrial uncouplers as anti-cancer agents.

MAJOR CONCLUSIONS

There is a large body of evidence supporting the therapeutic use of mitochondrial uncouplers to treat cancer. However, the long-term safety of some uncouplers remains in question and it will be critical to identify which patients and cancer types would benefit most from these agents.

Synthesis, biological evaluation and molecular docking studies of novel 1,2,3-triazole-quinazolines as antiproliferative agents displaying ERK inhibitory activity

ERK1/2 inhibitors have attracted special attention concerning the ability of circumventing cases of innate or log-term acquired resistance to RAF and MEK kinase inhibitors. Based on the 4-aminoquinazoline pharmacophore of kinases, herein we describe the synthesis of 4-aminoquinazoline derivatives bearing a 1,2,3-triazole stable core to bridge different aromatic and heterocyclic rings using copper-catalysed azide-alkyne cycloaddition reaction (CuAAC) as a Click Chemistry strategy. The initial screening of twelve derivatives in tumoral cells (CAL-27, HN13, HGC-27, and BT-20) revealed that the most active in BT-20 cells (25a, IC₅₀ 24.6 μM and a SI of 3.25) contains a more polar side chain (sulfone). Furthermore, compound 25a promoted a significant release of lactate dehydrogenase (LDH), suggesting the induction of cell death by necrosis. In addition, this compound induced G0/G1 stalling in BT-20 cells, which was accompanied by a decrease in the S phase. Western blot analysis of the levels of p-STAT3, p-ERK, PARP, p53 and cleaved caspase-3 revealed p-ERK1/2 and p-STA3 were drastically decreased in BT-20 cells under 25a incubation, suggesting the involvement of these two kinases in the mechanisms underlying 25a-induced cell cycle arrest, besides loss of proliferation and viability of the breast cancer cell. Molecular docking simulations using the ERK-ulixertinib crystallographic complex showed compound 25a could potentially compete with ATP for binding to ERK in a slightly higher affinity than the reference ERK1/2 inhibitor. Further in silico analyses showed comparable toxicity and pharmacokinetic profiles for compound 25a in relation to ulixertinib.

Novel ureido-dihydropyridine scaffolds as theranostic agents

In this work, the synthesis of interesting urea derivatives 5 based on 1,4-dihydropyridines 3 is described for the first time. Considering that both families exhibit potential as drugs to treat various diseases, their activity as anticancer agents has been evaluated in HeLa (cervix), Jurkat (leukaemia) and A549 (lung) cancer cell lines as well as on healthy mice in vivo. In general, whereas 1,4-dihydropyridines show a moderate cytotoxic activity, their urea analogues cause an extraordinary increase in their antiproliferative activity, specially towards HeLa cells. Because of the chiral nature of these compounds, enantiomerically enriched samples were also tested, showing different cytotoxic activity than the racemic mixture. Although the reason is not clear, it could be caused by a complex amalgam of physical and chemical contributions. The studied compounds also exhibit luminescent properties, which allow performing a biodistribution study in cancer cells. They have emission maxima between 420 and 471 nm, being the urea derivatives in general red shifted. Emission quenching was observed for those compounds containing a nitro group (3e,f and 5e,f). Fluorescence microscopy showed that 1,4-dihydropyridines 3a and 3g localised in the lysosomes, in contrast to the urea derivatives 5h that accumulated in the cell membrane. This different distribution could be key to explain the differences found in the cytotoxic activity and in the mechanism of action. Interestingly, a preliminary in vivo study regarding the acute toxicity of some of these compounds on healthy mice has been conducted, using a concentration up to 7200 times higher than the corresponding IC₅₀ value. No downgrade in the welfare of the tested mice was observed, which could support their use in preclinical tumour models.

An overview of spirooxindole as a promising scaffold for novel drug discovery

Introduction: Spirooxindole, a unique and versatile scaffold, has been widely studied in some fields such as pharmaceutical chemistry and synthetic chemistry. Especially in the application of medicine, quite a few compounds featuring spirooxindole motif have displayed excellent and broad pharmacological activities. Many identified candidate molecules have been used in clinical trials, showing promising prospects.Areas covered: This article offers an overview of different applications and developments of spirooxindoles (including the related natural products and their derivatives) in the process of drug innovation, including such as in anticancer, antimicrobial, anti-inflammatory, analgesic, antioxidant, antimalarial, and antiviral activities. Furthermore, the crucial structure-activity relationships, molecular mechanisms, pharmacokinetic properties, and main synthetic methods of spirooxindoles-based derivatives are also reviewed.Expert opinion: Recent progress in the biological activity profiles of spirooxindole derivatives have demonstrated their significant position in present-day drug discovery. Furthermore, we believe that the multidirectional development of novel drugs containing this core scaffold will continue to be the research hotspot in medicinal chemistry in the future.

Four-Component Fusion Protocol with NiO/ZrO2 as a Robust Recyclable Catalyst for Novel 1,4-Dihydropyridines

Nickel oxide loaded on zirconia (NiO/ZrO₂) as an expedient catalyst is reported for the synthesis of 18 unsymmetrical 1,4-dihydropyridine derivatives. The Lewis acidic nature of the catalyst proved an excellent choice for the one-pot, four-component fusion reaction with excellent yields of 89-98% and a completion time of 20-45 min. Mechanistic studies show that enamine and imine functionalities are the two possible pathways for the formation of 1,4-dihydropyridines with high selectivity. Crystal structures of two novel compounds (5a, 5c) were reported. The catalyst demonstrated reusability up to six cycles. The reaction at room temperature and ethanol as a solvent make this protocol green and economical.

1,4-Dihydropyridine: A Dependable Heterocyclic Ring with the Promising and the Most Anticipable Therapeutic Effects

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Nowadays, heterocyclic compounds act as a scaffold and are the backbone of medicinal chemistry. Among all of the heterocyclic scaffolds, 1,4-Dihydropyridine (1,4-DHP) is one of the most important heterocyclic rings that possess prominent therapeutic effects in a very versatile manner and plays an important role in synthetic, medicinal, and bioorganic chemistry. The main aim of the study is to review and encompass relevant studies related to 1,4-DHP and excellent therapeutic benefits of its derivatives. An extensive review of Pubmed-Medline, Embase and Lancet’s published articles was done to find all relevant studies on the activity of 1,4-DHP and its derivatives. 1,4-DHP is a potent Voltage-Gated Calcium Channel (VGCC) antagonist derivative which acts as an anti-hypertensive, anti- anginal, anti-tumor, anti-inflammatory, anti-tubercular, anti-cancer, anti-hyperplasia, anti-mutagenic, anti-dyslipidemic, and anti-ulcer agent. From the inferences of the study, it can be concluded that the basic nucleus, 1,4-DHP which is a voltage-gated calcium ion channel blocker, acts as a base for its derivatives that possess different important therapeutic effects. There is a need of further research of this basic nucleus as it is a multifunctional moiety, on which addition of different groups can yield a better drug for its other activities such as anti-convulsant, anti-oxidant, anti-mutagenic, and anti-microbial. This review would be significant for further researches in the development of several kinds of drugs by representing successful matrix for the medicinal agents.

Unsymmetric dihydropyridines bearing 2-pyridyl methyl carboxylate as modulators of P-glycoprotein; synthesis and biological evaluation in resistant and non-resistant cancer cells

Multi-drug resistance (MDR) in cancer cells is often associated with overexpression of P-glycoprotein (P-gp or ABCB1 or MDR1); therefore, modulators of this transporter might be helpful in overcoming MDR. In this study, 16 novel unsymmetrical dihydropyridine (DHP) derivatives bearing 2-pyridyl methyl carboxylate at C3 and a nitroimidazole or nitrophenyl ring at C4 positions of the DHP ring were synthesized. Their cytotoxicity was tested against four human cancer cells by MTT assay. The reversal capacity of MDR was examined in P-gp overexpressing cells (MES-SA/DX5) by measuring the alteration of doxorubicin’s IC50 and performing flow cytometric determination of intracellular rhodamine 123 accumulation. The calcium channel blocking (CCB) activity, as a side effect of DHPs, was tested on the ileum of a guinea pig. Molecular docking was performed to explain the binding mode of compounds. Two derivatives, 4a and 4c, containing 4-nitrophenyl at C4 and possessing methyl (4a) and iso-propyl (4c) carboxylates at the C5 position of DHP core demonstrated superior cytotoxic and MDR reversal activities and lower CCB effect. Docking analysis confirmed the importance of the 4-nitrophenyl ring for P-gp inhibitory activity. Some of the synthesized DHP derivatives with considerable MDR reversal capacity could be promising compounds for further discovery of useful agents for management of drug resistant cancer.

Crystal structure of diethyl 2-(4-methoxyphenyl)-1-phenyl-1,2-dihydropyridine-3,5-dicarboxylate, C24H25NO5

C24H25NO5, triclinic, P1̄, a = 9.2625(8) Å, b = 10.5974(10) Å, c = 11.7431(11) Å, α = 77.836(8)°, β = 87.564(8)°, γ = 66.951(9)°, V = 1035.83(17) Å3, Z = 2, R gt(F) = 0.0404, wR ref(F 2) = 0.0985, T = 107.5 K.

Increased Expression of LAMTOR5 Predicts Poor Prognosis and Is Associated with Lymph Node Metastasis of Head and Neck Squamous Cell Carcinoma

Late endosomal/lysosomal adaptor and MAPK and mTOR activator 5 (LAMTOR5) is a novel oncoprotein associated with several human malignancies, but its clinical role in head and neck squamous cell carcinoma (HNSCC) remains unclear. The present study aims to investigate the clinical and pathological significance of LAMTOR5 in HNSCC. We utilized immunohistochemical staining of human tissue microarrays (210 primary HNSCC, 42 normal oral mucosae, 69 oral epithelial dysplasia, and 68 metastasis lymph nodes) to explore the clinical and pathological significance of LAMTOR5 in HNSCC. Additionally, expression level of LAMTOR5 in immunoreactivity of Pten conditional knock out (Pten cKO) mice HNSCC was also assessed. We found LAMTOR5 was overexpressed in human and Pten cKO mice HNSCC, and its expression was significantly associated with patients' overall survival, lymph node metastasis and lymph node grade. Furthermore, LAMTOR5 expression was significantly correlated with the expression of p-Akt^Ser473, p-S6^Ser235/236, immune checkpoints (PD-L1, Galectin 9, VISTA and B7-H4) and macrophage markers (CD68 and CD163). In Pten cKO mice HNSCC, it was also significantly correlated with VISTA and F4/80. Consequently, we consider that high expression of LAMTOR5 might be a poor prognostic indicator and correlated with the immunosuppression of tumor microenvironment.