RESUMEN
Utilizing isoquinoline as a carrier ligand, we have evaluated the reactivity of selected transplatinum planar amine (TPA) carboxylate compounds by varying the leaving carboxylate group (acetate, hydroxyacetate, and lactate) in an effort to optimize the cytotoxic and metabolic efficiency. To measure the pharmacological properties of these compounds, a combination of systematic biophysical and biological studies were carried out mainly involving substitution reaction with NAM (N-acetyl-methionine), effects on DNA structural perturbation, cytotoxicity, cellular accumulation, metabolic stability, and cell cycle effects. TPA compounds showed minimal losses in cytotoxic efficacy and outperformed cisplatin after pre-incubation with serum, while displaying a distinct micromolar cytotoxic activity with minimal DNA binding and unaltered cell cycle. Monitoring the TPA compounds with NAM suggests the following trend for the reactivity: hydroxyacetate > lactate > acetate. The same trend was seen for the cytotoxicity in tumor cells and DNA binding, while the rate of drug inactivation/protein binding in cells was not significantly different among these leaving groups. Thus, our results show superior cellular efficacy of TPA compounds and distinct micromolar cytotoxic activities different than cisplatin. Moreover, we found the TPA compounds had prolonged survival and decreased tumor burden compared to the control mice in a relevant human ovarian cancer mouse model with A2780 cells expressing luciferase. Therefore, we propose that further optimization of the basic TPA structure can give further enhanced in vivo activity and may eventually be translated into the development of clinically relevant non-traditional platinum drugs.
Asunto(s)
Antineoplásicos , Neoplasias Ováricas , Humanos , Animales , Femenino , Ratones , Platino (Metal)/farmacología , Platino (Metal)/química , Cisplatino/farmacología , Cisplatino/química , Línea Celular Tumoral , Compuestos Organoplatinos/química , Antineoplásicos/farmacología , Antineoplásicos/química , ADN/química , Acetatos , Lactatos , Glicolatos , Ensayos de Selección de Medicamentos AntitumoralesRESUMEN
The cellular accumulation and the underlying mechanisms for the two ruthenium-based anticancer complexes [RuII(cym)(HQ)Cl] 1 (cym = η6-p-cymene, HQ = 8-hydroxyquinoline) and [RuII(cym)(PCA)Cl]Cl 2 (PCA = N-fluorophenyl-2-pyridinecarbothioamide) were investigated in HCT116 human colorectal carcinoma cells. The results showed that the cellular accumulation of both complexes increased over time and with higher concentrations, and that 2 accumulates in greater quantities in cells than 1. Inhibition studies of selected cellular accumulation mechanisms indicated that both 1 and 2 may be transported into the cells by both passive diffusion and active transporters, similar to cisplatin. Efflux experiments indicated that 1 and 2 are subjected to efflux through a mechanism that does not involve p-glycoprotein, as addition of verapamil did not make any difference. Exploring the influence of the Cu transporter by addition of CuCl2 resulted in a higher accumulation of 1 and 2 whilst the amount of Pt detected was slightly reduced when cells were treated with cisplatin. Complexes 1 and 2 were further explored in zebrafish where accumulation and distribution were determined with ICP-MS and LA-ICP-MS. The results correlated with the in vitro observations and zebrafish treated with 2 showed higher Ru contents than those treated with 1. The distribution studies suggested that both complexes mainly accumulated in the intestines of the zebrafish.
Asunto(s)
Antineoplásicos , Complejos de Coordinación , Rutenio , Animales , Humanos , Pez Cebra , Cisplatino , Rutenio/química , Antineoplásicos/farmacología , Antineoplásicos/química , Complejos de Coordinación/farmacología , Complejos de Coordinación/química , Línea Celular TumoralRESUMEN
Four platinum(IV) prodrugs incorporating a biotin moiety to selectively target cancer cells were synthesised, characterised, and their biological activity assessed. All complexes exhibited exceptional in vitro cytotoxicity against a panel of cancer cell lines, with [Pt(5,6-dimethyl-1,10-phenanthroline)(1S,2S-diaminocyclohexane)(biotin)(hydroxido)](NO3)2, (2) exhibiting the lowest GI50 of 4 nM in the prostate Du145 cancer cell line. Each complex displayed significantly enhanced activity compared to cisplatin, with 2 being 1000-fold more active in the HT29 colon cancer cell line. Against the MCF-7 breast cancer cell line, in which high levels of biotin receptors are expressed, 2, [Pt(4,7-dimethoxy-1,10-phenanthroline)(1S,2S-diaminocyclohexane)(biotin)(hydroxido)](NO3)2, (3), and [Pt(5-methyl-1,10-phenanthroline)(1S,2S-diaminocyclohexane)(biotin)(hydroxido)](NO3)2, (4) exhibited enhanced activity compared to their platinum(II) cores, with 4 being 6-fold more active than its platinum(II) precursor. Furthermore, 3 exhibited 3-fold greater selectivity towards MCF-7 breast cancer cells compared to MCF10A breast healthy cells, and this was further confirmed by platinum uptake studies, which showed 3 to have almost 3-fold greater uptake in MCF-7 cells, compared to MCF10A cells. The results show that lipophilicity and selectivity both contributed to the cellular uptake of 1-4; however, this was not always translated to the observed cytotoxicity.
RESUMEN
Soy isoflavones (SIs) show various health benefits, such as antioxidant and estrogenic effects. It is important to understand the bioaccessibility and bioavailability of SIs due to the close relation to their bioactivities. In this study, the antioxidant capacity, bioaccessibility, and bioavailability of 12 SIs were evaluated using radical-scavenging methods, simulations of human digestion, and Caco-2 cells in Transwell, respectively. All SIs were stable (91.1-99.2%) under gastric digestion conditions compared with the control (100%), whereas acetyl and malonyl conjugates were unstable (38.5% and 65.5%, respectively) under small intestinal digestion conditions. SI aglycones showed higher permeability (7-15 times) and cellular accumulation (8.8 times) than their glucosides. A small amount of SI conjugates was intact in the cell and in the basolateral side of each Transwell. These results suggest that SI conjugates, especially malonyl and acetyl forms, have incidental bioactivity after being metabolized to aglycones inside the cell.
Asunto(s)
Glycine max , Isoflavonas , Antioxidantes , Disponibilidad Biológica , Células CACO-2 , Digestión , HumanosRESUMEN
Widespread Plasmodium falciparum resistance to first-line antimalarials underscores the vital need to develop compounds with novel modes of action and identify new druggable targets. Here, we profile five compounds that potently inhibit P. falciparum asexual blood stages. Resistance selection studies with three carboxamide-containing compounds, confirmed by gene editing and conditional knockdowns, identify point mutations in the parasite transporter ABCI3 as the primary mediator of resistance. Selection studies with imidazopyridine or quinoline-carboxamide compounds also yield changes in ABCI3, this time through gene amplification. Imidazopyridine mode of action is attributed to inhibition of heme detoxification, as evidenced by cellular accumulation and heme fractionation assays. For the copy-number variation-selecting imidazopyridine and quinoline-carboxamide compounds, we find that resistance, manifesting as a biphasic concentration-response curve, can independently be mediated by mutations in the chloroquine resistance transporter PfCRT. These studies reveal the interconnectedness of P. falciparum transporters in overcoming drug pressure in different parasite strains.
Asunto(s)
Antimaláricos , Antagonistas del Ácido Fólico , Malaria Falciparum , Parásitos , Quinolinas , Transportadoras de Casetes de Unión a ATP/genética , Animales , Antimaláricos/farmacología , Antimaláricos/uso terapéutico , Hemo , Malaria Falciparum/tratamiento farmacológico , Malaria Falciparum/parasitología , Proteínas de Transporte de Membrana/genética , Plasmodium falciparum/genética , Plasmodium falciparum/metabolismo , Proteínas Protozoarias/genética , Proteínas Protozoarias/metabolismo , Quinolinas/farmacologíaRESUMEN
The cell envelope structure of Gram-negative bacteria is unique, composed of two lipid bilayer membranes and an aqueous periplasmic space sandwiched in between. The outer membrane constitutes an extra barrier to limit the exchange of molecules between the cells and the exterior environment. Donnan potential is a membrane potential across the outer membrane, resulted from the selective permeability of the membrane, which plays a pivotal role in the permeability of many antibiotics. In this review, we discussed factors that affect the intensity of the Donnan potential, including the osmotic strength and pH of the external media, the osmoregulated periplasmic glucans trapped in the periplasmic space, and the displacement of cell surface charges. The focus of our discussion is the impact of Donnan potential on the cellular permeability of selected antibiotics including fluoroquinolones, tetracyclines, ß-lactams, and trimethoprim.
RESUMEN
Hundreds of millions of people worldwide are exposed to unacceptable levels of carcinogenic inorganic arsenic. Animal models have shown that selenium and arsenic are mutually protective through the formation and elimination of the seleno-bis(S-glutathionyl) arsinium ion [(GS)2AsSe]-. Consistent with this, human selenium deficiency in arsenic-endemic regions is associated with arsenic-induced disease, leading to the initiation of human selenium supplementation trials. In contrast to the protective effect observed in vivo, in vitro studies have suggested that selenite increases arsenite cellular retention and toxicity. This difference might be explained by the rapid conversion of selenite to selenide in vivo. In the current study, selenite did not protect the human hepatoma (HepG2) cell line against the toxicity of arsenite at equimolar concentrations, however selenide increased the IC50 by 2.3-fold. Cytotoxicity assays of arsenite + selenite and arsenite + selenide at different molar ratios revealed higher overall mutual antagonism of arsenite + selenide toxicity than arsenite + selenite. Despite this protective effect, in comparison to 75Se-selenite, HepG2 cells in suspension were at least 3-fold more efficient at accumulating selenium from reduced 75Se-selenide, and its accumulation was further increased by arsenite. X-ray fluorescence imaging of HepG2 cells also showed that arsenic accumulation, in the presence of selenide, was higher than in the presence of selenite. These results are consistent with a greater intracellular availability of selenide relative to selenite for protection against arsenite, and the formation and retention of a less toxic product, possibly [(GS)2AsSe]-.
Asunto(s)
Arsenitos/toxicidad , Sustancias Protectoras/farmacología , Ácido Selenioso/farmacología , Compuestos de Selenio/farmacología , Arsénico/metabolismo , Arsenitos/metabolismo , Células Hep G2 , Humanos , Inactivación Metabólica/efectos de los fármacos , Sustancias Protectoras/metabolismo , Radioisótopos/metabolismo , Ácido Selenioso/metabolismo , Selenio/metabolismo , Compuestos de Selenio/metabolismo , Radioisótopos de Selenio/metabolismoRESUMEN
Drugs that accumulate in lysosomes reach very high tissue concentrations, which is evident in the high volume of distribution and often lower clearance of these compounds. Such a pharmacokinetic profile is beneficial for indications where high tissue penetration and a less frequent dosing regime is required. Here, we show how the level of lysosomotropic accumulation in cells can be predicted solely from molecular structure. To develop quantitative structure-activity relationship (QSAR) models, we used cellular accumulation data for 69 lysosomotropic macrocycles, the pharmaceutical class for which this type of prediction model is extremely valuable due to the importance of cellular accumulation for their anti-infective and anti-inflammatory applications as well as due to the fact that they are extremely difficult to model by computational methods because of their large size (Mw > 500). For the first time, we show that five levels of intracellular lysosomotropic accumulation (as measured by liquid chromatography coupled to tandem mass spectrometry-LC-MS/MS), from low/no to extremely high, can be predicted with 60% balanced accuracy solely from the compound's structure. Although largely built on macrocycles, the eight non-macrocyclic compounds that were added to the set were found to be well incorporated by the models, indicating their possible broader application. By uncovering the link between the molecular structure and cellular accumulation as the key process in tissue distribution of lysosomotropic compounds, these models are applicable for directing the drug discovery process and prioritizing the compounds for synthesis with fine-tuned accumulation properties, according to the desired pharmacokinetic profile.
Asunto(s)
Biología Computacional/métodos , Lisosomas/química , Compuestos Macrocíclicos/farmacocinética , Cromatografía Liquida , Compuestos Macrocíclicos/química , Estructura Molecular , Relación Estructura-Actividad Cuantitativa , Espectrometría de Masas en Tándem , Distribución TisularRESUMEN
Pharmaceutical excipients are no longer considered inert and have been shown to influence the activity of metabolic enzymes and transporters, resulting in altered pharmacokinetics of substrate drugs. In this study, the effect of 25 excipients commonly used in drug formulations were investigated for their effect on P-glycoprotein (P-gp) activity. The effect of excipients on P-gp were assessed by measuring the change in the cellular accumulation of a P-gp substrate, digoxin, in MDCK-MDR1 (Madin Darby canine kidney transfected with multidrug resistance 1 gene) cells. The cells were exposed to low (10 µM) and high (200 µM) concentrations of excipient along with 10 µM digoxin. Excipient concentrations were chosen to span the range of concentrations previously used for investigating activities in vitro. At 10 µM of excipient, an increase in the intracellular digoxin concentration was seen with d-α-tocopherol poly-(ethylene glycol) succinate (Vit-E-PEG; p = 0.002), poly(ethylene oxide)20 sorbitan monooleate (Tween 80; p = 0.001), cetyltrimethylammonium bromide (CTAB; p = 0.021), poly(ethylene oxide)35 modified castor oil (Cremophor EL; p = 0.01), polyethylene glycol15-hydroxystearate (Solutol HS 15; p = 0.006), and poly(ethylene glycol) hexadecyl ether (Brij 58; p = 0.001). At 200 µM, Vit-E-PEG ( p < 0.0001), sodium 1,4-bis (2-ethylhexoxy)-1,4-dioxobutane-2-sulfonate (AOT; p < 0.0001), Tween 80 ( p < 0.0001), CTAB ( p = 0.004), poly(ethylene oxide)20 sorbitan monolaurate (Tween 20; p < 0.0001), Cremophor EL ( p < 0.0001), Solutol HS 15 ( p < 0.0001), Brij 58 ( p < 0.0001), and sodium carboxymethyl cellulose (NaCMC; p = 0.006) increased intracellular digoxin significantly. Concentration-dependent inhibition of P-gp was then investigated for selected excipients giving an IC50 for Vit-E-PEG (12.48 µM), AOT (192.5 µM), Tween 80 (45.29 µM), CTAB (96.67 µM), Tween 20 (74.15 µM), Cremophor EL (11.92 µM), Solutol HS 15 (179.8 µM), Brij 58 (25.22 µM), and NaCMC (46.69 µM). These data add to the growing body of evidence demonstrating that not all excipients are inert and will aid excipient choice for rational formulation development.
Asunto(s)
Composición de Medicamentos/métodos , Excipientes/farmacología , Subfamilia B de Transportador de Casetes de Unión a ATP/antagonistas & inhibidores , Subfamilia B de Transportador de Casetes de Unión a ATP/genética , Subfamilia B de Transportador de Casetes de Unión a ATP/metabolismo , Animales , Digoxina/análisis , Digoxina/metabolismo , Perros , Células de Riñón Canino Madin Darby , TransfecciónRESUMEN
Gliomas are one of the most aggressive and treatment-resistant types of human brain cancer. Identification and evaluation of anticancer properties of compounds found in plants, such as naringenin (N) and 8-prenylnaringenin (8PN), are among the most promising applications in glioma therapy. The prenyl group seems to be crucial to the anticancer activity of flavones, since it may lead to enhanced cell membrane targeting and thus increased intracellular activity. It should be noted that 8PN content in hop cones is 10 to 100 times lower compared to other flavonoids, such as xanthohumol. In the study presented, we used a simple method for the synthesis of 8PN from isoxanthohumol-O-demethylation, with a high yield of 97%. Cellular accumulation and cytotoxicity of naringenin and 8-prenylnaringenin in normal (BJ) and cancer cells (U-118 MG) was also examined. Obtained data indicated that 8-prenylnaringenin exhibited higher cytotoxicity against used cell lines than naringenin, and the effect of both flavones was stronger in U-118 MG cells than in normal fibroblasts. The anticancer properties of 8PN correlated with its significantly greater (37%) accumulation in glioblastoma cells than in normal fibroblasts. Additionally, naringenin demonstrated higher selectivity for glioblastoma cells, as it was over six times more toxic for cancer than normal cells. Our results provide evidence that examined prenylated and non-prenylated flavanones have different biological activities against normal and cancer cell lines, and this property may be useful in designing new anticancer drugs for glioblastoma therapy.
Asunto(s)
Antineoplásicos Fitogénicos/farmacología , Fibroblastos/efectos de los fármacos , Flavanonas/farmacología , Línea Celular Tumoral , Supervivencia Celular/efectos de los fármacos , Flavanonas/síntesis química , Glioblastoma , Humanos , Estructura MolecularRESUMEN
The aim of this study was to investigate lipophilicity and cellular accumulation of rationally designed azithromycin and clarithromycin derivatives at the molecular level. The effect of substitution site and substituent properties on a global physico-chemical profile and cellular accumulation of investigated compounds was studied using calculated structural parameters as well as experimentally determined lipophilicity. In silico models based on the 3D structure of molecules were generated to investigate conformational effect on studied properties and to enable prediction of lipophilicity and cellular accumulation for this class of molecules based on non-empirical parameters. The applicability of developed models was explored on a validation and test sets and compared with previously developed empirical models.
Asunto(s)
Antibacterianos/química , Antibacterianos/farmacocinética , Azitromicina/análogos & derivados , Azitromicina/farmacocinética , Claritromicina/análogos & derivados , Claritromicina/farmacocinética , Humanos , Modelos Biológicos , Modelos Químicos , Conformación Molecular , Simulación de Dinámica MolecularRESUMEN
Solid drug nanoparticles (SDNs) are a nanotechnology with favourable characteristics to enhance drug delivery and improve the treatment of several diseases, showing benefit for improved oral bioavailability and injectable long-acting medicines. The physicochemical properties and composition of nanoformulations can influence the absorption, distribution, and elimination of nanoparticles; consequently, the development of nanoparticles for drug delivery should consider the potential role of nanoparticle characteristics in the definition of pharmacokinetics. The aim of this study was to investigate the pharmacological behaviour of efavirenz SDNs and the identification of optimal nanoparticle properties and composition. Seventy-seven efavirenz SDNs were included in the analysis. Cellular accumulation was evaluated in HepG2 (hepatic) and Caco-2 (intestinal), CEM (lymphocyte), THP1 (monocyte), and A-THP1 (macrophage) cell lines. Apparent intestinal permeability (Papp) was measured using a monolayer of Caco-2 cells. The Papp values were used to evaluate the potential benefit on pharmacokinetics using a physiologically based pharmacokinetic model. The generated SDNs had an enhanced intestinal permeability and accumulation in different cell lines compared to the traditional formulation of efavirenz. Nanoparticle size and excipient choice influenced efavirenz apparent permeability and cellular accumulation, and this appeared to be cell line dependent. These findings represent a valuable platform for the design of SDNs, giving an empirical background for the selection of optimal nanoparticle characteristics and composition. Understanding how nanoparticle components and physicochemical properties influence pharmacological patterns will enable the rational design of SDNs with desirable pharmacokinetics.
RESUMEN
Reduced susceptibility to antimicrobials in Gram-negative bacteria may result from multiple resistance mechanisms, including increased efflux pump activity or reduced porin protein expression. Up-regulation of the efflux pump system is closely associated with multidrug resistance (MDR). To help investigate the role of efflux pumps on compound accumulation, a fluorescence-based assay was developed using fluorescent derivatives of trimethoprim (TMP), a broad-spectrum synthetic antibiotic that inhibits an intracellular target, dihydrofolate reductase (DHFR). Novel fluorescent TMP probes inhibited eDHFR activity with comparable potency to TMP, but did not kill or inhibit growth of wild type Escherichia coli. However, bactericidal activity was observed against an efflux pump deficient E. coli mutant strain (ΔtolC). A simple and quick fluorescence assay was developed to measure cellular accumulation of the TMP probe using either fluorescence spectroscopy or flow cytometry, with validation by LC-MS/MS. This fluorescence assay may provide a simple method to assess efflux pump activity with standard laboratory equipment.
Asunto(s)
Antibacterianos/metabolismo , Escherichia coli/metabolismo , Trimetoprim/metabolismo , Antibacterianos/química , Escherichia coli/química , Escherichia coli/genética , Escherichia coli/crecimiento & desarrollo , Proteínas de Escherichia coli/genética , Proteínas de Escherichia coli/metabolismo , Citometría de Flujo , Proteínas de Transporte de Membrana/genética , Proteínas de Transporte de Membrana/metabolismo , Mutación , Espectrometría de Masas en Tándem , Trimetoprim/químicaRESUMEN
The current study aims to elucidate the possible reasons for the significantly different pharmacological behavior of platinum(IV) complexes with cisplatin-, carboplatin- or nedaplatin-like cores and how this difference can be related to their main physicochemical properties. Chlorido-containing complexes are reduced fast (within hours) by ascorbate and are able to unwind plasmid DNA in the presence of ascorbate, while their tri- and tetracarboxylato analogs are generally inert under the same conditions. Comparison of the lipophilicity, cellular accumulation and cytotoxicity of the investigated platinum compounds revealed the necessity to define new structure-property/activity relationships (SPRs and SARs). The higher activity and improved accumulation of platinum(IV) complexes bearing Cl(-) in equatorial position cannot only be attributed to passive diffusion facilitated by their lipophilicity. Therefore, further platinum accumulation experiments under conditions where active/facilitated transport mechanisms are suppressed were performed. Under hypothermic conditions (4°C), accumulation of dichloridoplatinum(IV) complexes is reduced down to 10% of the amount determined at 37°C. These findings suggest the involvement of active and/or facilitated transport in cellular uptake of platinum(IV) complexes with a cisplatin-like core. Studies with ATP depletion mediated by oligomycin and low glucose partially confirmed these observations, but their feasibility was severely limited in the adherent cell culture setting.
Asunto(s)
Antineoplásicos/farmacología , Complejos de Coordinación/farmacología , Compuestos Organoplatinos/farmacología , Platino (Metal)/química , Adenosina Trifosfato/antagonistas & inhibidores , Adenosina Trifosfato/metabolismo , Antineoplásicos/síntesis química , Transporte Biológico , Carboplatino/química , Línea Celular Tumoral , Supervivencia Celular/efectos de los fármacos , Cisplatino/química , Frío , Complejos de Coordinación/síntesis química , Glucosa/deficiencia , Glucosa/farmacología , Células Hep G2 , Humanos , Interacciones Hidrofóbicas e Hidrofílicas , Ligandos , Oligomicinas/farmacología , Compuestos Organoplatinos/síntesis química , Compuestos Organoplatinos/química , Oxidación-Reducción , Profármacos/química , Profármacos/farmacología , Relación Estructura-ActividadRESUMEN
Kiteplatin, the neglected drug analogous of cisplatin but containing cis-1,4-DACH in place of the two ammines, has been recently reevaluated for its activity against cisplatin- and oxaliplatin-resistant tumors, in particular colo-rectal cancer. With the aim of further improving the pharmacological activity of this drug, Pt(IV) prodrugs were derived by addition of two, differently substituted, benzoate groups in axial positions (X-ray structure). The cytotoxic activity of both compounds resulted markedly potentiated reaching nanomolar concentration against a wide panel of human cancer cells. The ability of benzoate ligands to enhance the activity of kiteplatin most likely originates from their lipophilicity promoting a higher drug accumulation in cancer cells; however, it is to be noted that the increase in pharmacological effect is far greater than the increase in cellular uptake. Overcoming cisplatin- and oxaliplatin-resistance by kiteplatin derivatives appears to relate to the inability of membrane extrusion pumps to remove active Pt species from tumor cells.
Asunto(s)
Antineoplásicos/síntesis química , Benzoatos/química , Compuestos Organoplatinos/síntesis química , Platino (Metal)/química , Profármacos/síntesis química , Células A549 , Antineoplásicos/farmacología , Transporte Biológico , Línea Celular Tumoral , Supervivencia Celular/efectos de los fármacos , Cisplatino/farmacología , Cristalografía por Rayos X , Resistencia a Antineoplásicos/efectos de los fármacos , Humanos , Ligandos , Células MCF-7 , Modelos Moleculares , Compuestos Organoplatinos/farmacología , Oxaliplatino , Profármacos/farmacologíaRESUMEN
A series of Pt(IV) anticancer prodrug candidates, having the equatorial arrangement of cisplatin and bearing two aliphatic carboxylato axial ligands, has been investigated to prove the relationship between lipophilicity, cellular accumulation, DNA platination and antiproliferative activity on the cisplatin-sensitive A2780 ovarian cancer cell line. Unlike cisplatin, no facilitated influx/efflux mechanism appears to operate in the case of the Pt(IV) complexes under investigation, thus indicating that they enter by passive diffusion. While Pt(IV) complexes having lipophilicity comparable to that of cisplatin (negative values of log Po/w) exhibit a cellular accumulation similar to that of cisplatin, the most lipophilic complexes of the series show much higher cellular accumulation (stemming from enhanced passive diffusion), accompanied by greater DNA platination and cell growth inhibition. Even if the Pt(IV) complexes are removed from the culture medium in the recovery process, the level of DNA platination remains very high and persistent in time, indicating efficient storing of the complexes and poor detoxification efficiency.
Asunto(s)
Antineoplásicos/farmacología , Aductos de ADN/metabolismo , Compuestos Organoplatinos/farmacología , Profármacos/farmacología , Adenosina Trifosfatasas/química , Adenosina Trifosfatasas/metabolismo , Antineoplásicos/síntesis química , Antineoplásicos/metabolismo , Ácido Ascórbico/química , Proteínas de Transporte de Catión/química , Proteínas de Transporte de Catión/metabolismo , Línea Celular Tumoral , Proliferación Celular/efectos de los fármacos , Cisplatino/química , Cisplatino/metabolismo , Cisplatino/farmacología , Transportador de Cobre 1 , ATPasas Transportadoras de Cobre , Aductos de ADN/química , Difusión , Glutatión/química , Humanos , Interacciones Hidrofóbicas e Hidrofílicas , Oligopéptidos/química , Compuestos Organoplatinos/síntesis química , Compuestos Organoplatinos/metabolismo , Oxidación-Reducción , Fragmentos de Péptidos , Profármacos/síntesis química , Profármacos/metabolismoRESUMEN
Substitutionally inert Pt(IV) prodrugs, combining bioactive axial ligands with Pt(IV) derivatives of antitumor Pt(II) compounds, represent a new generation of anticancer drugs. The rationale behind these prodrugs is to release, by reductive elimination inside the cancer cell, an active Pt(II) drug which binds nuclear DNA as well as bioactive ligands that may potentiate toxic effects of the Pt(II) drugs by an independent pathway. Platinum prodrugs, such as Pt(IV) derivatives of cisplatin containing axial valproic acid (VPA) ligands, destroy cancer cells with greater efficacy than conventional cisplatin. These axial ligands were chosen because VPA inhibits histone deacetylase (HDAC) activity, thereby decondensing chromatin and subsequently increasing the accessibility of DNA within chromatin to DNA-binding agents. We examined the mechanism of cytotoxic activity of Pt(IV) derivatives of cisplatin with VPA axial ligands. Particular attention was paid to the role of the VPA ligand in these Pt(IV) prodrugs in the mechanism underlying their toxic effects in human ovarian tumor cells. We demonstrate that (i) treatment of the cells with these prodrugs resulted in enhanced histone H3 acetylation and decondensation of heterochromatin markedly more effectively than free VPA; (ii) of the total Pt inside the cells, a considerably higher fraction of Pt from the Pt(IV)-VPA conjugates is bound to DNA than from the conjugates with biologically inactive ligands. The results indicate that the enhanced cytotoxicity of the Pt(IV)-VPA conjugates is a consequence of several processes involving enhanced cellular accumulation, downregulation of HDACs and yet other biochemical processes (not involving HDACs) which may potentiate antitumor effects.
Asunto(s)
Epigénesis Genética , Compuestos Organoplatinos/metabolismo , Neoplasias Ováricas/metabolismo , Ácido Valproico/metabolismo , Acetilación , Línea Celular Tumoral , Femenino , Glutatión/metabolismo , Histona Desacetilasas/metabolismo , Histonas/metabolismo , Humanos , Espectroscopía de Resonancia Magnética , Compuestos Organoplatinos/química , Neoplasias Ováricas/genética , Neoplasias Ováricas/patología , Ácido Valproico/químicaRESUMEN
The novel guanidine compounds trans-[Pt(NH2Me)2{NH=C(NHMe)NR}2](Cl)2 (R=NEt2 [7], NC5H10 [8]) (trans-7,8) were synthesized by the nucleophilic addition of methylamine to dialkylcyanamide ligands of the push-pull nitrile complexes trans-[PtCl2(RCN)2] (R=NEt2, NC5H10). In vitro cytotoxicity tests conducted for the entire series of the guanidine complexes, i.e. trans-7,8, the neutral cis- or trans-[PtCl2{NH=C(NH2)R}2] (cis-1-3 and trans-1-3) and the cationic cis- or trans-[Pt(NH3)2{NH=C(NH2)R}2](Cl)2 (cis-4-6 and trans-4-6) (R=NMe2 [1,4], NEt2 [2,5], NC5H10 [3,6]) in two human cancer cell lines, CH1 (ovarian carcinoma) and SW480 (colon cancer), confirmed that the cytotoxicity of several trans-configured (trans-3,6) complexes is higher than that of cis-congeners (cis-3,6). Cellular platinum levels were analyzed by inductively coupled plasma mass spectrometry upon treatment of SW480 cells, revealing a dependence of cellular accumulation on the geometrical isomerism and the steric hindrance of the variable substituent R on the guanidine ligand. DNA interactions of selected guanidine complexes were studied in order to find hints for the possible reasons for their different activities. Changes induced to the electrophoretic mobility of a dsDNA plasmid confirmed the potency of the guanidine complexes (e.g. trans-1,3,5,6 and cis-1,3,4) to significantly alter DNA secondary structure, indicating DNA as a possible critical target of these compounds.
Asunto(s)
Antineoplásicos/síntesis química , ADN/efectos de los fármacos , Guanidina/síntesis química , Compuestos Organoplatinos/síntesis química , Antineoplásicos/química , Antineoplásicos/farmacología , Línea Celular Tumoral , Guanidina/química , Guanidina/farmacología , Humanos , Ligandos , Estructura Molecular , Neoplasias/tratamiento farmacológico , Compuestos Organoplatinos/química , Compuestos Organoplatinos/farmacología , Platino (Metal)/química , Estereoisomerismo , Relación Estructura-ActividadRESUMEN
ETHNOPHARMACOLOGICAL RELEVANCE: Lotus plumule, the dried young cotyledon and radicle of the Nelumbo nucifera Gaertn. (Fam. Nymphaeaceae) ripe seed, is a famous Traditional Chinese Medicine to remove heat from the heart, anchor the mind, improve seminal emission, and arrest bleeding for centuries in China. Liensinine and its analogs neferine and isoliensinine are the major active components in lotus plumule. Aim of the study is to investigate the association of liensinine, neferine, and isoliensinine with efflux transporters. MATERIALS AND METHODS: Caco-2, MDCK, MDCK-MDR1, and MDCK-MRP2 were used as cell models for the transcellular transport and accumulation studies. RESULTS: The results obtained in Caco-2 cells suggested that P-glycoprotein (P-gp) might be involved in transcellular transport. Cellular accumulation and transport experiments were further performed in MDCK-MDR1 cells. GF120918 and cyclosporine A were found to completely inhibit the efflux, and the net efflux ratios of these alkaloids exhibited saturation over the concentration range. No significant differences in liensinine accumulation and transport were observed between MDCK and MDCK-MRP2 cells. CONCLUSIONS: These results demonstrated that liensinine, neferine, and isoliensinine are substrates of P-gp, whereas MRP2 is not involved in the transport process, suggesting that P-gp might be responsible for the absorption and distribution of the 3 alkaloids.
Asunto(s)
Miembro 1 de la Subfamilia B de Casetes de Unión a ATP/metabolismo , Bencilisoquinolinas/farmacología , Isoquinolinas/farmacología , Fenoles/farmacología , Absorción , Animales , Transporte Biológico , Células CACO-2 , Supervivencia Celular/efectos de los fármacos , Perros , Humanos , Células de Riñón Canino Madin Darby , Proteína 2 Asociada a Resistencia a Múltiples Medicamentos , Proteínas Asociadas a Resistencia a Múltiples Medicamentos/metabolismoRESUMEN
OBJECTIVES: To determine the energy dependency of and the contribution of the membrane potential to the cellular accumulation of the dinuclear complexes [{Ru(phen)2}2{µ-bbn}](4+) (Rubbn) and the mononuclear complexes [Ru(Me4phen)3](2+) and [Ru(phen)2(bb7)](2+) in Staphylococcus aureus and Escherichia coli, and to examine their effect on the bacterial membrane. METHODS: The accumulation of the ruthenium complexes in bacteria was determined using flow cytometry at a range of temperatures. The cellular accumulation of the ruthenium complexes was also determined in cells that had been incubated with the metal complexes in the presence or absence of metabolic stimulators or inhibitors and/or commercial dyes to determine the membrane potential or membrane permeability. RESULTS: The accumulation of ruthenium complexes in the two bacterial strains was shown to increase with increasing incubation temperature, with the relative increase in accumulation greater with E. coli, particularly for Rubb12 and Rubb16. No decrease in accumulation was observed for Rubb12 in ATP-inhibited cells. While carbonyl cyanide m-chlorophenyl hydrazone (CCCP) did depolarize the cell membrane, no reduction in the accumulation of Rubb12 was observed; however, all ruthenium complexes, when incubated with S. aureus at concentrations twice their MIC, depolarized the membrane to a similar extent to CCCP. Except for the mononuclear complex [Ru(Me4phen)3](2+), incubation of any of the other ruthenium complexes allowed a greater quantity of the membrane-impermeable dye TO-PRO-3 to be taken up by S. aureus. CONCLUSIONS: The results indicate that the potential new antimicrobial Rubbn complexes enter the cell in an energy-independent manner, depolarize the cell membrane and significantly permeabilize the cellular membrane.