A novel benzotriazole derivative inhibits proliferation of human hepatocarcinoma cells by increasing oxidative stress concomitant mitochondrial damage

Carborane derivatives of 1,2,3-triazole depolarize mitochondria by transferring protons through the lipid part of membranes

Boron containing polyhedra (carboranes) are three-dimensional delocalized aromatic systems. These structures have been shown to transport protons through lipid membranes and mitochondria. Conjugation of carboranes to various organic moieties is aimed at obtaining biologically active compounds with novel properties. Taking advantage of 1,2,3-triazoles as the scaffolds valuable in medicinal chemistry, we synthesized 1-(o-carboranylmethyl)-4-pentyl-1,2,3-triazole (c-triazole) and 1-(o-carboranylmethyl)-4-pentyl-1,2,3-triazolium iodide (c-triazolium). Both compounds interacted with model lipid membranes and exhibited a proton carrying activity in planar bilayers and liposomes in a concentration- and pH-dependent manner. Importantly, mechanisms of the protonophoric activity differed; namely, protonation-deprotonation reactions of the triazole and the o-carborane moieties were involved in the transport cycles of c-triazole and c-triazolium, respectively. At micromolar concentrations, c-triazole and c-triazolium stimulated respiration of isolated rat liver mitochondria and depolarized their membrane potential, with c-triazole being more potent. In living K562 (human chronic myelogenous leukemia) cells, both c-triazolium and c-triazole altered the mitochondrial membrane potential as determined by a decreased intracellular accumulation of the potential-dependent dye tetramethylrhodamine ethyl ester. Finally, cell viability testing demonstrated a cytotoxic potency of c-triazolium and, to a lesser extent, of c-triazole against K562 cells, whereas non-malignant fibroblasts were much less sensitive. In all tests, the reference boron-free benzyl-4-pentyl-1,2,3-triazole showed little-to-no effects. These results demonstrated that carboranyltriazoles carry protons across biological membranes, a property potentially important in anticancer drug design.

Transcriptional and cellular effects of benzotriazole UV stabilizers UV-234 and UV-328 in the freshwater invertebrates Chlamydomonas reinhardtii and Daphnia magna

Benzotriazole ultra violet stabilizers (BZT-UVs) are compounds used in many applications and products to prevent photochemical degradation. Despite their widespread presence in aquatic ecosystems and persistence in the environment, there are very limited data on their effects and toxicity, and their modes of action remain largely unknown. The objectives of the present study were to evaluate the chronic effects of 2 BZT-UVs, 2-(2H-benzotriazol-2-yl)-4,6-bis(1-methyl-1-phenylethyl)phenol (UV-234) and 2-(2H-benzotriazol-2-yl)-4,6-di-tert-pentylphenol (UV-328), on the freshwater green algae Chlamydomonas reinhardtii and the freshwater crustacean Daphnia magna. Organisms were exposed to 0.01 and 10 μg/L of UV-234, UV-328, as well as a mixture of the 2 compounds. Life-history endpoints (viability, reproduction, and growth) and oxidative stress-related biomarkers (gene transcription, reactive oxygen species [ROS] production, and lipid peroxidation) were measured. Daphnia magna growth, reproduction, and gene transcription were not impacted by 21-d individual or mixed exposure. After 96-h of exposure, no differences were observed on the cellular viability of C. reinhardtii for either of the 2 BZT-UVs. In the algae, results showed increased ROS production in response to UV-328 and lipid peroxidation following exposure to UV-234. Synergistic effects of the 2 BZT-UVs were evident at the transcriptional level with 2 to 6 times up-regulation of glutathione peroxidase (gp_x ) in response to the mixture for all treatment conditions. The transcription of superoxide dismutase (sod), catalase (cat), and ascorbic peroxidase (apx) was also regulated by UV-234 and UV-328 in the green algae, most likely as a result of ROS production and lipid peroxidation. Results from the present study suggest potential impacts of UV-234 and UV-328 exposure on the antioxidant defense system in C. reinhardtii. Environ Toxicol Chem 2017;36:3333-3342. © 2017 Crown in the Right of Canada. Published by Wiley Periodicals Inc., on behalf of SETAC.

Benzotriazole: An overview on its versatile biological behavior

Discovered in late 1960, azoles are heterocyclic compounds class which constitute the largest group of available antifungal drugs. Particularly, the imidazole ring is the chemical component that confers activity to azoles. Triazoles are obtained by a slight modification of this ring and similar or improved activities as well as less adverse effects are reported for triazole derivatives. Consequently, it is not surprising that benzimidazole/benzotriazole derivatives have been found to be biologically active. Since benzimidazole has been widely investigated, this review is focused on defining the place of benzotriazole derivatives in biomedical research, highlighting their versatile biological properties, the mode of action and Structure Activity Relationship (SAR) studies for a variety of antimicrobial, antiparasitic, and even antitumor, choleretic, cholesterol-lowering agents.

Facile synthesis of 1-alkoxy-1H-benzo- and 7-azabenzotriazoles from peptide coupling agents, mechanistic studies, and synthetic applications

(1H-Benzo[d][1,2,3]triazol-1-yloxy)tris(dimethylamino)phosphonium hexafluorophosphate (BOP), 1H-benzo[d][1,2,3]triazol-1-yl 4-methylbenzenesulfonate (Bt-OTs), and 3H-[1,2,3]triazolo[4,5-b]pyridine-3-yl 4-methylbenzenesulfonate (At-OTs) are classically utilized in peptide synthesis for amide-bond formation. However, a previously undescribed reaction of these compounds with alcohols in the presence of a base, leads to 1-alkoxy-1H-benzo- (Bt-OR) and 7-azabenzotriazoles (At-OR). Although BOP undergoes reactions with alcohols to furnish 1-alkoxy-1H-benzotriazoles, Bt-OTs proved to be superior. Both, primary and secondary alcohols undergo reaction under generally mild reaction conditions. Correspondingly, 1-alkoxy-1H-7-azabenzotriazoles were synthesized from At-OTs. Mechanistically, there are three pathways by which these peptide-coupling agents can react with alcohols. From (31)P{(1)H}, [(18)O]-labeling, and other chemical experiments, phosphonium and tosylate derivatives of alcohols seem to be intermediates. These then react with BtO(-) and AtO(-) produced in situ. In order to demonstrate broader utility, this novel reaction has been used to prepare a series of acyclic nucleoside-like compounds. Because BtO(-) is a nucleofuge, several Bt-OCH2Ar substrates have been evaluated in nucleophilic substitution reactions. Finally, the possible formation of Pd π-allyl complexes by departure of BtO(-) has been queried. Thus, alpha-allylation of three cyclic ketones was evaluated with 1-(cinnamyloxy)-1H-benzo[d][1,2,3]triazole, via in situ formation of pyrrolidine enamines and Pd catalysis.

Oxidative stress induced in nurses by exposure to preparation and handling of antineoplastic drugs in Mexican hospitals: a multicentric study

The impact of involuntary exposure to antineoplastic drugs (AD) was studied in a group of nurses in diverse hospitals in Mexico. The results were compared with a group of unexposed nurses. Anthropometric characteristics and the biochemical analysis were analyzed in both groups. Also, lipid peroxidation level (LPX), protein carbonyl content (PCC), and activity of the antioxidant enzymes superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx) were evaluated in blood of study participants as oxidative stress (OS) biomarkers. The group of occupationally exposed (OE) nurses consisted of 30 individuals ranging in age from 25 to 35 years. The control group included 30 nurses who were not occupationally exposed to the preparation and handling of AD and whose anthropometric and biochemical characteristics were similar to those of the OE group. All biomarkers evaluated were significantly increased (P < 0.5) in OE nurses compared to the control group. Results show that the assessment of OS biomarkers is advisable in order to evaluate exposure to AD in nurses.

Modular synthesis of N-vinyl benzotriazoles

A modular approach to N1-vinyl benzotriazoles by azide-aryne cycloadditions and Julia-Kocienski reactions is described. Reactions of azidomethyl phenyl-1H-tetrazol-5-yl (PT) sulfide with arynes gave methyl(PT-sulfanyl)-substituted benzotriazoles in 68-89% yields. Oxidation of the sulfides to the sulfones gave the benzotriazole-substituted Julia-Kocienski reagents. Olefination reactions of aldehydes and a ketone with reagents derived from benzyne, 2,3-naphthyne, and 4,5-dimethoxybenzyne precursors proceeded to give various N1-vinyl benzotriazole derivatives. Olefination stereoselectivities are tunable for electron-rich aldehydes, but not for electron-deficient aldehydes and alkanals, where they proceed with good to excellent Z-stereoselectivity.

Benzyl isothiocyanate (BITC) and phenethyl isothiocyanate (PEITC)-mediated generation of reactive oxygen species causes cell cycle arrest and induces apoptosis via activation of caspase-3, mitochondria dysfunction and nitric oxide (NO) in human osteogenic sarcoma U-2 OS cells

Benzyl isothiocyanate (BITC) and phenethyl isothiocyanate (PEITC), a member of the isothiocyanate family, have been shown to exhibit antineoplastic ability against many human cancer cells. In this study, we found that exposure of human osteogenic sarcoma U-2 OS cells to BITC and PEITC led to induce morphological changes and to decrease the percentage of viable cells in a time- and dose-dependent manner. BITC and PEITC induced cell cycle arrest at G2/M phase at 48 h treatment and inhibited the levels of cell cycle regulatory proteins such as cyclin A and B1 in U-2 OS cells but promoted the level of Chk1 and p53 that led to G2/M arrest. BITC and PEITC induced a marked increase in apoptosis (DNA fragmentation) and poly(ADP-ribose)polymerase (PARP) cleavage, which was associated with mitochondrial dysfunction and the activation of caspase-9 and -3. BITC and PEITC also promoted the ROS production in U-2 OS cells and the N-acetylcysteine (NAC, an antoxidant agent) was pretreated and then treated with both compounds which led to decrease the levels of ROS and increase the cell viability. Interestingly, BITC and PEITC promoted the levels of NO production and increased the iNOS enzyme. Confocal laser microscope also demonstrated that BITC and PEITC promoted the release of cytochrome c and AIF, suggesting that both compounds induced apoptosis through ROS, caspase-3 and mitochondrial, and NO signaling pathways. Taken together, these molecular alterations and signaling pathways offer an insight into BITC and PEITC-caused growth inhibition, G2/M arrest, and apoptotic death of U-2 OS cells.

Synthesis, characterization, crystal structure and DFT studies on 3-(1H-benzo[d][1,2,3]triazol-1-yl)-1-oxo-1-m-tolylpropan-2-yl-nicotinate

3-(1H-Benzo[d][1,2,3]triazol-1-yl)-1-oxo-1-m-tolylpropan-2-yl-nicotinate (BOTN) has been synthesized and characterized by elemental analysis, IR, UV-vis and fluorescence spectroscopy. Its crystal structure has also been determined by X-ray single crystal diffraction. For BOTN, density functional theory (DFT) calculations of the structure and vibrational frequencies have been performed at B3LYP/6-311G** level. The comparisons between the experimental vibrational frequencies and the predicted data show that B3LYP/6-311G** method can simulate the IR of BOTN on the whole. Based on the vibration analysis, thermodynamic properties of BOTN have been calculated. The correlative equations between the thermodynamic properties and the temperatures have also been listed. The experimental UV-vis spectra present two peaks and theoretical UV-vis spectra obtained by TD-DFT method exhibit three peaks. The comparison between them suggests that the B3LYP/6-311G** method can only approximately simulate the UV-vis spectra of BOTN. The fluorescence determination reveals two emission bands at 423 and 489 nm, respectively.

Discovery of 1H-benzo[d][1,2,3]triazol-1-yl 3,4,5-trimethoxybenzoate as a potential antiproliferative agent by inhibiting histone deacetylase

Twenty-one benzotriazoles (3-16 and 18-24) were synthesized and half of them (5, 8-16, 20, and 21) were reported for the first time. Their antiproliferative activities against three human cancer cells were assayed. It revealed that 1H-benzo[d][1,2,3]triazol-1-yl 3,4,5-trimethoxybenzoate (9) showed considerable activity against three human cancer cell lines with the half maximal inhibitory concentration (IC(50)) values of 1.2-2.4 nM, which were close to the value of the positive control, doxorubicin. Further investigation indicated compound 9 was a potential histone deacetylase inhibitor (IC(50)=9.4 μM) and its binding mode was simulated using docking method.

Mitochondrially targeted anti-cancer agents

Cancer is an ever-increasing problem that is yet to be harnessed. Frequent mutations make this pathology very variable and, consequently, a considerable challenge. Intriguingly, mitochondria have recently emerged as novel targets for cancer therapy. A group of agents with anti-cancer activity that induce apoptosis by way of mitochondrial destabilisation, termed mitocans, have been a recent focus of research. Of these compounds, many are hydrophobic agents that associate with various sub-cellular organelles. Clearly, modification of such structures with mitochondria-targeting moieties, for example tagging them with lipophilic cations, would be expected to enhance their activity. This may be accomplished by the addition of triphenylphosphonium groups that direct such compounds to mitochondria, enhancing their activity. In this paper, we will review agents that possess anti-cancer activity by way of destabilizing mitochondria and their possible targets. We propose that mitochondrial targeting, in particular where the agent associates directly with the target, results in more specific and efficient anti-cancer drugs of potential high clinical relevance.

Diethyl (6-amino-9H-purin-9-yl) methylphosphonate induces apoptosis and cell cycle arrest in hepatocellular carcinoma BEL-7402 cells: Role of reactive oxygen species

The primary purpose of this work was to study the mechanism of the anti-proliferation activity of compound diethyl (6-amino-9H-purin-9-yl) methylphosphonate (DaMP), a novel acyclic nucleoside phosphonate. Using cell survival MTT assay, flow cytometry analysis, DNA laddering, DCF fluorescence detection and caspases assays, this study investigated the effects of this compound on cell apoptosis, cell cycle regulation and reactive oxygen species in human hepatocarcinoma BEL-7402 cell lines. Exposure to DaMP at 80 microM for 24 h, BEL-7402 cells displayed a marked retardation of S-phase progression, leading to a severe perturbation of normal cell cycle. In addition, DaMP also significantly inhibited cell proliferation by inducing apoptosis, disrupting DNA synthesis and increasing the activities of caspase-3 and -9, while the antioxidants could significantly inhibit these effects. This study was the first to demonstrate that DaMP could induce apoptosis and cell cycle arrest by producing reactive oxygen species and activating caspase-3 and -9.

Synthesis, characterization, crystal structure and DFT studies on 3-(1H-benzo[d][1,2,3]triazol-1-yl)-1-(4-ethylphenyl)-1-oxopropan-2-yl-4-ethylbenzoate

3-(1H-benzo[d][1,2,3]triazol-1-yl)-1-(4-ethylphenyl)-1-oxopropan-2-yl-4-ethyl-benzoate (BEOE) has been synthesized and characterized by elemental analysis, IR, UV-vis and fluorescence spectroscopy. Its crystal structure has also been determined by X-ray single crystal diffraction. For the title compound, density functional theory (DFT) calculations of the structure and vibrational frequencies have been performed at B3LYP/6-31G* level of theory. Based on the vibration analysis, thermodynamic properties of the title compound have been calculated. The correlative equations between the thermodynamic properties and temperatures have also been listed. By using TD-DFT method, electron spectra of the title compound have been predicted, which suggests the B3LYP/6-31G* method can approximately simulate the electron spectra for the system presented here.

Anticancer properties of Ganoderma lucidum methanol extracts in vitro and in vivo

Anticancer activities of various extracts of the medicinal mushroom, Ganoderma lucidum, have been widely demonstrated and are mainly associated with the presence of different bioactive polysaccharides and triterpenoids. We have evaluated and compared in vitro and in vivo the antitumor effects of two preparations from Ganoderma lucidum: a methanol extract containing total terpenoids (GLme) and a purified methanol extract containing mainly acidic terpenoids (GLpme). Both extracts inhibited tumor growth of B16 mouse melanoma cells inoculated subcutaneously into syngeneic C57BL/6 mice and reduced viability of B16 cells in vitro, whereby GLme exhibited stronger effect. Furthermore, anticancer activity of GLme was demonstrated for the first time against two other rodent tumor cell lines, L929-mouse fibrosarcoma and C6-rat astrocytoma. The mechanism of antitumor activity of GLme comprised inhibition of cell proliferation and induction of caspase-dependent apoptotic cell death mediated by upregulated p53 and inhibited Bcl-2 expression. Moreover, the antitumor effect of the GLme was associated with intensified production of reactive oxygen species, whereas their neutralization by the antioxidant, N-acetyl cysteine, resulted in partial recovery of cell viability. Thus, our results suggest that GLme might be a good candidate for treatment of diverse forms of cancers.