Natural Dibenzo[b,f]oxepines, Pacharin and Bauhiniastatin-1, Isolated from Bauhinia acuruana Induce Apoptosis on Breast Cancer Cells via MCL-1 Protein Reduction.

Herein, we describe the antiproliferative effects of two natural dibenzo [b,f]oxepines, pacharin and bauhiniastatin-1, isolated from Bauhinia acuruana on a breast cancer cell line and the mode of action underlying the cytotoxicity. Both compounds were cytotoxic in a panel of six tumor lines analyzed by the MTT assay, and IC50 values ranged from 7.8 to 45.1 µM, including human breast adenocarcinoma (MCF-7) cells. In contrast, none of the compounds were cytotoxic on normal human peripheral blood mononuclear cells (IC50 > 100 µM). Human breast adenocarcinoma (MCF-7) cells treated with pacharin or bauhiniastatin-1 20 µM for 24 h presented a reduction in cell volume and intensification of chromatin condensation, DNA fragmentation, and apoptotic cells. These findings became more evident after 48 h of exposure. Antiapoptotic B-cell lymphoma-2 family members, such as myeloid cell leukemia-1 and B-cell lymphoma-extra large, are important targets in cancer cells since their overexpression confers resistance to cancer treatments. A significant reduction of the myeloid cell leukemia-1 protein levels in human breast adenocarcinoma (MCF-7) cells after 24 h of treatment with pacharin or bauhiniastatin-1 at 20 µM was observed, while the B-cell lymphoma-extra large protein content was reduced in bauhiniastatin-1-treated cells at 40 µM only. The cytotoxic effects of pacharin and bauhiniastatin-1 are likely linked to myeloid cell leukemia-1 inhibition, which leads to the apoptosis of breast adenocarcinoma cells.

Chloroquine and hydroxychloroquine in antitumor therapies based on autophagy-related mechanisms.

Chloroquine (CQ) and hydroxychloroquine (HCQ) are the most common drugs used to relieve acute and chronic inflammatory diseases. In this article, we present a review about the use of CQ and HCQ in antitumor therapies based on autophagy mechanisms. These molecules break/discontinue autophagosome-lysosome fusions in initial phases and enhance antiproliferative action of chemotherapeutics. Their sensitizing effects of chemotherapy when used as an adjuvant option in clinical trials against cancer. However, human related-MDR genes are also under risk to develop chemo or radioresistance because cancer cells have ability to throw 4-aminoquinolines out from digestive vacuoles well. Additionally, they also have antitumor mechanism unrelated to autophagy, including cell death from apoptosis and necroptosis and immunomodulatory/anti-inflammatory properties. However, the link between some anticancer mechanisms, clinical efficacy and pharmacological safety has not yet been fully defined.

Pharmacological and physicochemical profile of arylacetamides as tools against human cancers.

Arylacetamides are widely used as synthetic intermediates to obtain medicinal substances. This work evaluated in vitro antiproliferative activity of ten 2-Chloro-N-arylacetamides on human normal and cancer cells and detailed in vivo toxicological and anticancer investigations. Initially, cytotoxic colorimetric assays were performed using tumor lines, peripheral blood mononuclear cells (PBMC) and erythrocytes. Compounds 2, 3 and 4 were tested for acute toxicity (50, 150 and 300 mg/kg) and for subacute antitumoral capacity in HCT-116 colon carcinoma-bearing xenograft mice for 15 days at 25 mg/kg/day. Most compounds revealed cytotoxic action on tumor lines and PBMC, but activity on human erythrocytes were not detected. Molecular dipole moment, lipophilicity and electronic constant of aryl substituents had effects upon in vitro antiproliferative capacity. More common in vivo acute behavioral signals with compounds 2, 3 and 4 were muscle relaxation, reduction of spontaneous locomotor activity and number of entries in closed arms and increased number of falls andtime spent in open arms, suggesting diazepam-like anxiolytic properties. Decrease of grabbing strength and overall activity were common, but palpebral ptosis and deaths occurred at 300 mg/kg only. Compounds 2 and 3 reduced colon carcinoma growth (21.2 and 27.5%, respectively, p < 0.05) without causing apparent signals of organ-specific toxicity after subacute exposure. The structural chemical simplicity of arylacetamides make them cost-effective alternatives and justifies further improvements to enhance activity, selectivity and the development of pharmaceutical formulations.

Ru(II)-Thymine Complex Causes Cell Growth Inhibition and Induction of Caspase-Mediated Apoptosis in Human Promyelocytic Leukemia HL-60 Cells.

Ruthenium-based compounds represent a class of potential antineoplastic drugs. Recently, we designed, synthesized, and identified the Ru(II)-thymine complex [Ru(PPh3)2(Thy)(bipy)]PF6 (where PPh = triphenylphosphine, Thy = thymine and bipy = 2,2'-bipyridine) as a potent cytotoxic agent with the ability to bind to DNA and human and bovine serum albumins. In this study, the underlying cytotoxic mechanism of the [Ru(PPh3)2(Thy)(bipy)]PF6 complex was assessed. This complex displayed potent cytotoxicity in different cancer cell lines; the morphology that is associated with apoptotic cell death, increased internucleosomal DNA fragmentation without cell membrane permeability, loss of the mitochondrial transmembrane potential, increased phosphatidylserine externalization, and caspase-3 activation were observed in human promyelocytic leukemia HL-60 cells that were treated with the complex. Moreover, pretreatment of HL-60 cells with Z-VAD(OMe)-FMK, a pan-caspase inhibitor, partially reduced the apoptosis that was induced by the complex, indicating that the apoptotic cell death occurred through a caspase-mediated pathway. In conclusion, the [Ru(PPh3)2(Thy)(bipy)]PF6 complex displays potent cytotoxicity to different cancer cells and induces caspase-mediated apoptosis in HL-60 cells.

Anti-liver cancer activity in vitro and in vivo induced by 2-pyridyl 2,3-thiazole derivatives.

A total of 24 hybrid compounds containing pyridyl and 1,3-thiazole moieties were screened against HL-60 (leukemia), MCF-7 (breast adenocarcinoma), HepG2 (hepatocellular carcinoma), NCI-H292 (lung carcinoma) human tumor cell lines and non-tumor cells (PBMC, human peripheral blood mononuclear cells). Most of them were highly potent in at least one cell line tested (IC50≤3µM), being HL-60 the most sensitive and HepG2 the most resistant cell line. Among them, TAP-07 and TP-07 presented cytotoxic activity in all tumor cell lines, including HepG2 (IC50 2.2 and 5.6µM, respectively) without antiproliferative effects to normal cells (PBMC) (IC50>30µM), making TAP-07 and TP-07, the compounds with the most favorable selectivity index. TAP-07 and TP-07 induced apoptosis in HepG2 cells and presented in vivo antitumor activity in hepatocellular xenograft cancer model in C.B-17 severe combined immunodeficient mice. Systemic toxicological verified by biochemical and histopathological techniques reveled no major signs of toxicity after treatment with TAP-07 and TP-07. Together the results indicated the anti-liver cancer activity of 2-pyridyl 2,3-thiazole derivatives.

Molecular Modeling and Physicochemical Properties of Supramolecular Complexes of Limonene with α- and ß-Cyclodextrins.

This study evaluated three different methods for the formation of an inclusion complex between alpha- and beta-cyclodextrin (α- and ß-CD) and limonene (LIM) with the goal of improving the physicochemical properties of limonene. The study samples were prepared through physical mixing (PM), paste complexation (PC), and slurry complexation (SC) methods in the molar ratio of 1:1 (cyclodextrin:limonene). The complexes prepared were evaluated with thermogravimetry/derivate thermogravimetry, infrared spectroscopy, X-ray diffraction, complexation efficiency through gas chromatography/mass spectrometry analyses, molecular modeling, and nuclear magnetic resonance. The results showed that the physical mixing procedure did not produce complexation, but the paste and slurry methods produced inclusion complexes, which demonstrated interactions outside of the cavity of the CDs. However, the paste obtained with ß-cyclodextrin did not demonstrate complexation in the gas chromatographic technique because, after extraction, most of the limonene was either surface-adsorbed by ß-cyclodextrin or volatilized during the procedure. We conclude that paste complexation and slurry complexation are effective and economic methods to improve the physicochemical character of limonene and could have important applications in pharmacological activities in terms of an increase in solubility.

Promising Effects of Casearins in Tumor-Bearing Mice and Antinociceptive Action against Oncologic Pain: Molecular Docking and In Vivo Findings.

Safer analgesic drugs remain a hard challenge because of cardiovascular and/or gastrointestinal toxicity, mainly. So, this study evaluated in vivo the antiproliferative actions of a fraction with casearins (FC) from Casearia sylvestris leaves against human colorectal carcinomas and antihyperalgesic effects on inflammatory- or opiate-based pain relief and oncologic pain in Sarcoma 180 (S180)-bearing mice. Moreover, docking investigations evaluated the binding among Casearin X and NMDA(N-methyl-D-aspartate)-type glutamate receptors. HCT-116 colorectal carcinoma-xenografted mice were treated with FC for 15 days. Antinociceptive assays included chemically induced algesia and investigated mechanisms by pharmacological blockade. Intraplantar region S180-bearing animals received a single dose of FC and were examined for mechanical allodynia and behavior alterations. AutoDock Vina determined molecular interactions among Cas X and NMDA receptor subunits. FC reduced tumor growth at i.p. (5 and 10 mg/kg) and oral (25 mg/kg/day) doses (31.12-39.27%). FC reduced abdominal pain, as confirmed by formalin and glutamate protocols, whose antinociception activity was blocked by naloxone and L-NAME (neurogenic phase) and naloxone, atropine, and flumazenil (inflammatory phase). Meanwhile, glibenclamide potentiated the FC analgesic effects. FC increased the paw withdrawal threshold without producing changes in exploratory parameters or motor coordination. Cas X generated a more stable complex with active sites of the NMDA receptor GluN2B subunits. FC is a promising antitumor agent against colorectal carcinomas, has peripheral analgesic effects by desensitizing secondary afferent neurons, and inhibits glutamate release from presynaptic neurons and/or their action on cognate receptors. These findings emphasize the use of clerodane diterpenes against cancer-related pain conditions.

Toxic profile of marinobufagin from poisonous Amazon toads and antitumoral effects on human colorectal carcinomas.

ETHNOPHARMACOLOGICAL RELEVANCE: South Americans natives have extensively used the toad "kururu" to reduce/treat skin infections, cutaneous lesions and sores. They release secretions rich in bufadienolides, polyhydroxy steroids with well-documented cardiotonic and antiproliferative actions, but in vivo antitumoral evaluations in mammals are rare, and toxicological safety has been left in second place. AIMS OF THE STUDY: This investigation used in silico, in vitro and in vivo tools to evaluate acute and subacute toxic effects of marinobufagin and the anticancer action in tumor-bearing mice models. MATERIALS AND METHODS: Initially, in silico toxic predictions were performed, followed by in vitro assays using human and murine normal and tumor lines. Next, acute and subacute studies on mice investigated the behavior, hematological and intestinal transit profile and antitumoral activity of marinobufagin in sarcoma 180- and HCT-116 colorectal carcinoma-transplanted mice for 7 and 15 days, respectively. Ex vivo and in vivo cytogenetic assays in Sarcoma 180 and bone marrow cells and histopathological examinations were also executed. RESULTS: In silico studies revealed ecotoxicological effects on crustaceans (Daphnia sp.), fishes (Pimephales promelas and Oryzias latipes), and algae. A 24-h marinobufagin-induced acute toxicity included signals of central activity, mainly (vocal frenzy, absence of body tonus, increased ventilation, ataxia, and equilibrium loss), and convulsions and death at 10 mg/kg. The bufadienolide presented effective in vitro cytotoxic action on human lines of colorectal carcinomas in a similar way to ouabain and tumor reduction in marinobufagin-treated SCID-bearing HCT-116 heterotopic xenografts. Animals under subacute nonlethal doses exhibited a decrease in creatinine clearance with normal levels of blood urea, probably as a result of a marinobufagin-induced renal perfusion fall. Nevertheless, only minor morphological side effects were identified in kidneys, livers, hearts and lungs. CONCLUSIONS: Marinobufagin has in vitro and in vivo anticancer action on colorectal carcinoma and mild and reversible alterations in key metabolic organs without direct chemotherapy-induced gastrointestinal effects at subacute exposure, but it causes acute ataxia, equilibrium loss, convulsions and death at higher acute exposure.

Arsenic Trioxide Triggers Apoptosis of Metastatic Oral Squamous Cells Carcinoma with Concomitant Downregulation of GLI1 in Hedgehog Signaling.

Given the lack of advances in Oral Squamous Cell Carcinoma (OSCC) therapy in recent years, pharmacological strategies to block OSCC-related signaling pathways have gained prominence. The present study aimed to evaluate the therapeutic potential of Arsenic Trioxide (ATO) concerning its antitumoral effects and the inhibition of the Hedgehog (HH) pathway in OSCC. Initially, ATO cytotoxicity was assessed in a panel of cell lines. Cell viability, cell cycle, death patterns, and cell morphology were analyzed, as well as the effect of ATO on the expression of HH pathway components. After the cytotoxic assay, HSC3 cells were chosen for all in vitro assays. ATO increased apoptotic cell death and nuclear fragmentation in the sub-G1 cell cycle phase and promoted changes in cell morphology. In addition, the reduced expression of GLI1 indicated that ATO inhibits HH activity. The present study provides evidence of ATO as an effective cytotoxic drug for oral cancer treatment in vitro.

Cytotoxicity of δ-tocotrienols from Kielmeyera coriacea against cancer cell lines.

In the search for new anti-cancer compounds, Brazilian Cerrado plant species have been investigated. The hexane root bark extract of Kielmeyera coriacea lead to a mixture of δ-tocotrienol (1) and its dimer (2). The structures of both compounds 1 and 2 were established based on detailed 1D and 2D NMR and EI-MS analyses. The cytotoxicity of the mixture was tested against four human tumor cell lines in the following cultures: MDA-MB-435 (melanoma), HCT-8 (colon), HL-60 (leukemia), and SF-295 (glioblastoma), and displayed IC(50) values ranging from 8.08 to 23.58µg/mL. Additional assays were performed in order to investigate the mechanism of action of the mixture (1+2) against the human leukemia cell line HL-60. The results suggested that the mixture suppressed leukemia growth and reduced cell survival, triggering both apoptosis and necrosis, depending on the concentration.

Aminoquinolines as Translational Models for Drug Repurposing: Anticancer Adjuvant Properties and Toxicokinetic-Related Features.

The indiscriminate consumption of antimalarials against coronavirus disease-2019 emphasizes the longstanding clinical weapons of medicines. In this work, we conducted a review on the antitumor mechanisms of aminoquinolines, focusing on the responses and differences of tumor histological tissues and toxicity related to pharmacokinetics. This well-defined analysis shows similar mechanistic forms triggered by aminoquinolines in different histological tumor tissues and under coexposure conditions, although different pharmacological potencies also occur. These molecules are lysosomotropic amines that increase the antiproliferative action of chemotherapeutic agents, mainly by cell cycle arrest, histone acetylation, physiological changes in tyrosine kinase metabolism, inhibition of PI3K/Akt/mTOR pathways, cyclin D1, E2F1, angiogenesis, ribosome biogenesis, triggering of ATM-ATR/p53/p21 signaling, apoptosis, and presentation of tumor peptides. Their chemo/radiotherapy sensitization effects may be an adjuvant option against solid tumors, since 4-aminoquinolines induce lysosomal-mediated programmed cytotoxicity of cancer cells and accumulation of key markers, predominantly, LAMP1, p62/SQSTM1, LC3 members, GAPDH, beclin-1/Atg6, α-synuclein, and granules of lipofuscin. Adverse effects are dose-dependent, though most common with chloroquine, hydroxychloroquine, amodiaquine, and other aminoquinolines are gastrointestinal changes, blurred vision ventricular arrhythmias, cardiac arrest, QTc prolongation, severe hypoglycemia with loss of consciousness, and retinopathy, and they are more common with chloroquine than with hydroxychloroquine and amodiaquine due to pharmacokinetic features. Additionally, psychological/neurological effects were also detected during acute or chronic use, but aminoquinolines do not cross the placenta easily and low quantity is found in breast milk despite their long mean residence times, which depends on the coexistence of hepatic diseases (cancer-related or not), first pass metabolism, and comedications. The low cost and availability on the world market have converted aminoquinolines into "star drugs" for pharmaceutical repurposing, but a continuous pharmacovigilance is necessary because these antimalarials have multiple modes of action/unwanted targets, relatively narrow therapeutic windows, recurrent adverse effects, and related poisoning self-treatment. Therefore, their use must obey strict rules, ethical and medical prescriptions, and clinical and laboratory monitoring.

Cytotoxic and Antifungal Amides Derived from Ferulic Acid: Molecular Docking and Mechanism of Action.

Amides derived from ferulic acid have a wide spectrum of pharmacological activities, including antitumor and antifungal activity. In the present study, a series of ten amides were obtained by coupling reactions using the reagents (benzotriazol-1-yloxy) tripyrrolidinophosphonium hexafluorophosphate (PyBOP) and N,N'-dicyclohexylcarbodiimide (DCC). All the compounds were identified on the basis of their IR, 1H- and 13C-NMR, HRMS data, and with yields ranging from 43.17% to 91.37%. The compounds were subjected to cytotoxic tests by the alamar blue technique and antifungal screening by the broth microdilution method to determine the minimum inhibitory concentration (MIC). The amides 10 and 11 displayed the best result in both biological evaluations, and compound 10 was the most potent and selective in HL-60 cancer cells, with no cytotoxicity on healthy cells. This amide had antifungal activity in all strains and had the lowest MIC against Candida albicans and Candida tropicalis. The possible mechanism of antifungal action occurs via the fungal cell wall. Molecular modeling suggested that compounds 10 and 11 interact with the enzymes GWT1 and GSC1, which are essential for the development of C. albicans. The findings of the present study demonstrated that compounds 10 and 11 may be used as a platform in drug development in the future.

Hedgehog pathway activation in oral squamous cell carcinoma: cancer-associated fibroblasts exhibit nuclear GLI-1 localization.

The purpose of this study was to evaluate the expression of Hedgehog (HH) signaling molecules (SHH and GLI-1) by cancer-associated fibroblasts (CAF) in oral squamous cell carcinoma (OSCC). Immunohistochemistry was used to detect molecular HH signaling and CAF-related protein expression, including α-SMA and S100A4, in 70 samples of human OSCC. The colocalization of α-SMA and S100A4 with SHH was also evaluated by double-staining. In vitro study was performed using primary normal oral fibroblast (NOF) and CAF through immunofluorescence and Western Blot for CAF-proteins, SHH, and GLI-1. Forty-five cases (64.28%) were positive for α-SMA exclusively in tumor stroma, and S100A4 was identified in the cytoplasm of CAFs in 94.28% (n = 66) of the cases. With respect to stromal cells, 64 (91.43%) OSCC cases were positive for SHH, and 31 were positive for GLI-1 (44.29%); positive correlations were found between SHH and α-SMA (p < 0.0001, φ = 0.51), as well as between SHH and S100A4 (p = 0.087, φ = 0.94). Protein expression of SHH and GLI-1 was observed in primary CAFs and NOFs. Although SHH was found to be localized in the cellular cytoplasm of both cell types, GLI-1 was present only in the nuclei of CAF. Our results indicate that CAFs are not only potential sources of HH ligands in tumor stroma, but may also respond to HH signaling through nuclear GLI-1 activation. We further observed that elevated SHH expression by OSCC cells was associated with higher CAF density, reinforcing the chemoattractant role played by these molecules.

Inhibition of CAL27 Oral Squamous Carcinoma Cell by Targeting Hedgehog Pathway With Vismodegib or Itraconazole.

Oral Squamous Cell Carcinoma (OSCC) presents an important challenge for the health systems worldwide. Thus, unraveling the biological mechanisms involved in OSCC pathogenesis is essential to the discovery of new drugs with anticancer potential. The Hedgehog (HH) pathway has shown promising results as a therapeutic target both in vitro and in vivo. This study aimed to investigate the effects of vismodegib and itraconazole on the expression of Hedgehog (HH) genes (PTCH1, SMO, and GLI1), cell cycle and cell death in OSCC cells. Alamar Blue assay was used to assess the cytotoxicity of vismodegib and itraconazole in a panel of oral cancer cell lines, including CAL27. The expression of HH signaling components after treatment with vismodegib and itraconazole, at concentrations of 25 or 50 µg/ml was evaluated by qPCR. Cell cycle and apoptosis were evaluated by flow cytometry after 72 h treatment with 50 µg/ml of vismodegib or itraconazole. HH signaling was activated in OSCC cell lines CAL27, SCC4, SCC9, and HSC3. Vismodegib and itraconazole significantly reduced CAL27 cell viability after 48 h of treatment. Gene expression of PTCH1, SMO, and GLI1 decreased in response to 24 h of treatment with vismodegib or itraconazole. Furthermore, CAL27 cells exhibited alterations in morphology, cell size, and cellular granularity. An increase in the DNA fragmentation was observed after treatment and both inhibitors induced apoptosis after 72 h. In conclusion, SMO inhibitors vismodegib and itraconazole demonstrably reduced the expression of HH genes in CAL27 OSCC cell line. In addition, treatment with vismodegib and itraconazole reduced cellular viability and altered the morphology of CAL27 cells, and also induced apoptosis.

Characterization of ß-cyclodextrin/myrtenol complex and its protective effect against nociceptive behavior and cognitive impairment in a chronic musculoskeletal pain model.

Myrtenol has gained wide interest because of its pharmacological profiles, mainly for treatment of chronic diseases. To improve the solubility of myrtenol, the formation of inclusion complexes with ß-cyclodextrin was performed by physical mixture, kneading process or slurry complexation (SC) methods and characterized using thermal analysis, XRD, SEM and NMR. From these results, myrtenol complexed by SC was successfully complexed into ß-cyclodextrin cavity. The interaction between myrtenol and ß-cyclodextrin was confirmed by molecular docking. Hence, the SC ß-cyclodextrin-myrtenol complex was evaluate for its anti-hyperalgesic, anxiolytic and antioxidant activity in a fibromyalgia model. Results show that myrtenol and ß-cyclodextrin form a stable complex and have anti-hyperalgesic effect, improve the cognitive impairment caused and have an anxiolytic-like effect. Furthermore, the ß-cyclodextrin/myrtenol complex decrease lipoperoxidation, increased catalase activity and a reduce SOD/CAT ratio. Therefore, ß-cyclodextrin/myrtenol complex reduce painful behavior, improves motor skills and emotional behavior and decreases oxidative stress in a fibromyalgia model.

An investigation into the interaction between piplartine (piperlongumine) and human serum albumin.

Piplartines are alkaloid amides present in the roots and stems of different pepper species which have promising pharmacological properties including cancer prevention. Some recent studies have determined pharmacokinetic parameters of piplartine in rat blood plasma but without pointing to any molecular target or describing the physicochemical forces of the interaction. The present study investigated the interaction between piplartine and human serum albumin (HSA) the predominant protein in blood plasma. Fluorescence spectroscopy was utilized to observe the complex HSA-piplartine formation. Thermodynamic parameter analysis indicates that the process occurs spontaneously and is enthalpically driven; the affinity constant suggests that this interaction is reversible. This was reinforced by the binding density function method and by the displacement analysis that the piplartine binds on HSA at a single site, which was determined to be the IIA sub-domain. In silico analysis (molecular docking) identified the main residues involved in binding and the corresponding forces, which corroborates well with the experimental results.

Antitumor activity of two derivatives from 2-acylamine-1, 4-naphthoquinone in mice bearing S180 tumor.

Drugs containing a quinone moiety, such as anthracyclines, mitoxantrones and lapachol, show excellent anticancer activity. In this study, 2-butanoylamine-1,4-naphthoquinone (1) and 2-propanoylamine-1,4-naphthoquinone (2) derivatives from 2-amine-1 ,4-naphthoquinone were synthesized, and their antitumor activity in mice bearing Sarcoma 180 tumor were examined. In addition, hematology and biochemistry analyses, as well as, histopathological and morphological analyses were performed in order to evaluate the toxicological aspects of the naphthoquinones treatment. Both naphthoquinones showed potente antitumor activity. The inhibition rates were 33.48 and 42.35% for (1) and 37.65 and 55.24% for (2) at the dose of 25 and 50 mg/kg/day, respectively. In the histopathological analysis, the naphthoquinones showed only weak toxicity. Neither enzimatic activity of transaminases (aspartate aminotransferase-AST nor alanine aminotransferase-ALT), urea level nor hematological paramenter were significantly modified after naphthoquinones treatment. These data reinforce the anticancer potential of naphthoquinones derivatives.

Evaluation of the genotoxicity of piplartine, an alkamide of Piper tuberculatum, in yeast and mammalian V79 cells.

The genus Piper belongs to the Piperaceae family, and includes species of commercial and medicinal importance. Chemical studies on Piper species resulted in the isolation of several biologically active molecules, including alkaloid amides, such as piplartine. This molecule, isolated from Piper tuberculatum, has significant cytotoxic activity against tumor cell lines, and presents antifungal, anti-platelet aggregation, anxiolytic, and antidepressant effects. In order to understand the biological properties of piplartine, this study investigated the genotoxicity and the induction of apoptosis by piplartine in V79 cells and its mutagenic and recombinogenic potential in Saccharomyces cerevisiae. Piplartine induced dose-dependent cytotoxicity in S. cerevisiae cultures in either stationary -- or exponential growth phase. In addition, piplartine was not mutagenic when cells were treated during exponential-growth phase and kept in buffer solution, but it increased the frequencies of point, frameshift, and forward mutations when cells were treated in medium during growth. Piplartine treatment induced DNA strand breaks in V79 cells, as detected by neutral and alkaline comet assay. In cell cycle analysis, piplartine induced G2/M cell cycle arrest, probably as a consequence of the DNA damage induced and repair. Moreover, piplartine treatment induced apoptosis in a dose-dependent manner, as observed by a decrease in mitochondrial membrane potential and an increase in internucleosomal DNA fragmentation. These data suggest that the DNA damage caused by piplartine induces G2/M cell cycle arrest, followed by apoptosis. Moreover, we suggest that cells surviving piplartine-induced DNA damage can accumulate mutations, since this alkaloid was mutagenic and recombinogenic in S. cerevisiae assays.

A ruthenium-based 5-fluorouracil complex with enhanced cytotoxicity and apoptosis induction action in HCT116 cells.

Combination of multifunctionalities into one compound is a rational strategy in medicinal chemical design, and have often been used with metallodrug-based compounds. In the present study, we synthesized a novel ruthenium-based 5-fluorouracil complex [Ru(5-FU)(PPh3)2(bipy)]PF6 (PPh3 = triphenylphosphine; and bipy = 2,2'-bipyridine) with enhanced cytotoxicity in different cancer cells, and assessed its apoptosis induction action in human colon carcinoma HCT116 cells. The complex was characterized by infrared, cyclic voltammetry, molar conductance measurements, elemental analysis, NMR experiments and X-ray crystallographic analysis. In both 2D and 3D cell culture models, the complex presented cytotoxicity to cancer cells more potent than 5-FU. A typical morphology of apoptotic cell death, increased internucleosomal DNA fragmentation, without cell membrane permeability, loss of the mitochondrial transmembrane potential, increased phosphatidylserine externalization and caspase-3 activation were observed in complex-treated HCT116 cells. Moreover, the pre-treatment with Z-DEVD-FMK, a caspase-3 inhibitor, reduced the apoptosis induced by the complex, indicating cell death by apoptosis through caspase-dependent and mitochondrial intrinsic pathways. The complex failed to induce reactive oxygen species production and DNA intercalation. In conclusion, the novel complex displays enhanced cytotoxicity to different cancer cells, and is able to induce caspase-mediated apoptosis in HCT116 cells.

Antimalarials and macrolides: a review of off-label pharmacotherapies during the first wave of the SARS-CoV-2 pandemic

Abstract We critically analyzed clinical trials performed with chloroquine (CQ) and hydroxychloroquine (HCQ) with or without macrolides during the first wave of COVID-19 and discussed the design and limitations of peer-reviewed studies from January to July 2020. Seventeen studies were eligible for the discussion. CQ and HCQ did not demonstrate clinical advantages that justified their inclusion in therapeutic regimens of free prescription for treatment or prophylactic purposes, as suggested by health authorities, including in Brazil, during the first wave. Around August 2020, robust data had already indicated that pharmacological effects of CQ, HCQ and macrolides as anti-SARS-CoV-2 molecules were limited to in vitro conditions and largely based on retrospective trials with low quality and weak internal validity, which made evidence superficial for decision-making. Up to that point, most randomized and nonrandomized clinical trials did not reveal beneficial effects of CQ or HCQ with or without macrolides to reduce lethality, rate of intubation, days of hospitalization, respiratory support/mechanical ventilation requirements, duration, type and number of symptoms, and death and were unsuccessful in increasing virus elimination and/or days alive in hospitalized or ambulatory patients with COVID-19. In addition, many studies have demonstrated that side effects are more common in CQ-or HCQ-treated patients.