N-acetylcysteine (NAC), often used as an antioxidant-scavenging reactive oxygen species (ROS) in vitro, was recently shown to increase the cytotoxicity of other compounds through ROS-dependent and ROS-independent mechanisms. In this study, NAC itself was found to induce extensive ROS production in human leukemia HL-60 and U937 cells. The cytotoxicity depends on ROS-modulating enzyme expression. In HL-60 cells, NAC activated NOX2 to produce superoxide (O2•-). Its subsequent conversion into H2O2 by superoxide dismutase 1 and 3 (SOD1, SOD3) and production of ClO- from H2O2 by myeloperoxidase (MPO) was necessary for cell death induction. While the addition of extracellular SOD potentiated NAC-induced cell death, extracellular catalase (CAT) prevented cell death in HL-60 cells. The MPO inhibitor partially reduced the number of dying HL-60 cells. In U937 cells, the weak cytotoxicity of NAC is probably caused by lower expression of NOX2, SOD1, SOD3, and by the absence of MOP expression. However, even here, the addition of extracellular SOD induced cell death in U937 cells, and this effect could be reversed by extracellular CAT. NAC-induced cell death exhibited predominantly apoptotic features in both cell lines. Conclusions: NAC itself can induce extensive production of O2•- in HL-60 and U937 cell lines. The fate of the cells then depends on the expression of enzymes that control the formation and conversion of ROS: NOX, SOD, and MPO. The mode of cell death in response to NAC treatment bears apoptotic and apoptotic-like features in both cell lines.
- MeSH
- acetylcystein farmakologie MeSH
- HL-60 buňky MeSH
- katalasa genetika MeSH
- leukemie farmakoterapie genetika metabolismus MeSH
- lidé MeSH
- NADPH-oxidasa 2 genetika MeSH
- oxidační stres účinky léků MeSH
- peroxidasa genetika MeSH
- proliferace buněk účinky léků MeSH
- reaktivní formy kyslíku metabolismus MeSH
- regulace genové exprese u nádorů účinky léků MeSH
- stanovení celkové genové exprese MeSH
- superoxiddismutasa genetika MeSH
- U937 buňky MeSH
- viabilita buněk účinky léků MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
The pharmaceutical industry has to tackle the explosion of high amounts of poorly soluble APIs. This phenomenon leads to numerous sophisticated solutions. These include the use of multifactorial data analysis identifying correlations between the components and dosage form properties, laboratory and production process parameters with respect to the API liberation Example of such API is bicalutamide. Improved liberation is achieved by particle size reduction. Laboratory batches, with different PSD of API, were filled into gelatinous capsules and consequently granulated for tablet compression. Comparative dissolution profiles with Casodex 150 mg (Astra Zeneca) were performed. The component analysis was used for the statistical evaluation of f1 and f2 factors and D(v,0.9) and D[4,3] parameters of PSD to identify optimal PSD values. Suitable PSD limits for API were statistically confirmed in laboratory and in commercial scale with respect to optimized tablet properties. The tablets were bioequivalent with originator (n = 20; 90% CI for ln AUC0-120: 99.8-111.9%; 90% CI for ln cmax: 101.1-112.9%). In conclusion, the micronisation of the API is still an efficient and inexpensive method improving the bioavailability, although there are more complicated and expensive methods available. Statistical multifactorial methods improved the safety and reproducibility of production.
- MeSH
- anilidy chemická syntéza metabolismus MeSH
- biologická dostupnost MeSH
- farmaceutická chemie metody MeSH
- multivariační analýza MeSH
- nitrily chemická syntéza metabolismus MeSH
- tablety MeSH
- terapeutická ekvivalence MeSH
- tosylové sloučeniny chemická syntéza metabolismus MeSH
- Publikační typ
- časopisecké články MeSH
V rámci této experimentální studie byly připraveny biodegradovatelné mikročástice (MČ) na bázi kopolymeru kyseliny mléčné a glykolové (PLGA) metodou odpaření rozpouštědla z jednoduché emulze o/v. Mikročástice obsahovaly nerozpustné antidepresivum mirtazapin. Příprava mikročástic zahrnovala formulační proměnné, a to obsah polymeru (700, 900 nebo 1200 mg), dichlormethanu (5 nebo 10 ml), a/nebo léčiva (200 nebo 400 nebo 600 mg) a objem vodné fáze emulze (400, 600 nebo 800 ml). U sledovaných parametrů byl pozorován vliv na velikost mikročástic a jejich morfologii, enkapsulační účinnost a disoluční chování. Všechny mikročástice byly úspěšně připraveny a jejich velikost se pohybovala v intervalu 165,34 ± 42,88 až 360,17 ± 121,59 μm. Mikročástice vykazovaly prodloužené uvolňování léčiva (v rámci dní), přičemž u některých z nich byl pozorován vícefázový charakter. Bylo zjištěno, že při použití vyššího počátečního množstvím PLGA byly připraveny větší MČ s delším lag time, a to až 34,3 hodin. Na druhé straně vyšší množství použitého léčiva vedlo ke zkrácení lag time. Snížení objemu vnější fáze a násobně vyšší množství dichlormethanu zpomalilo uvolňování mirtazapinu a snížilo enkapsulační účinnost. Výsledky byly dále potvrzeny vícerozměrnou analýzou dat.
In this experimental study, the biodegradable polylactide-co-glycolide (PLGA) microparticles (MP) loaded with the insoluble antidepressant mirtazapine were prepared by the simple o/w solvent evaporation method. The formation involved intrinsic variables, such as the content of polymer (700, 900 or 1200 mg), dichloromethane (5 or 10 ml) and/or drug (200 or 400 or 600 mg), and the volume of the aqueous emulsion phase (400, 600 or 800 ml). The influence of these parameters on the size and morphology of microparticles, encapsulation efficiency, and drug release behavior was observed. All MP were successfully prepared, and their size ranged between 165.34 ± 42.88 and 360.17 ± 121.59 μm. MP exhibited prolonged drug release (days), and some profiles had multiphasic character. It was found that the samples prepared with a higher initial amount of PLGA were bigger with prolonged lag time up to 34.3 hours. On the other hand, higher drug concentrations reduced the lag time. The external phase volume reduction and multiplication of dichloromethane amount prolonged the mirtazapine release and decreased the encapsulation efficiency. These observations were further confirmed by multivariate data analysis.
- Klíčová slova
- PLGA, metoda odpaření rozpouštědla,
- MeSH
- léky s prodlouženým účinkem MeSH
- lidé MeSH
- mirtazapin * farmakologie MeSH
- nanočástice MeSH
- nanočásticový lékový transportní systém MeSH
- příprava léků MeSH
- Check Tag
- lidé MeSH
Glioblastoma multiforme (GBM) is the most common primary brain tumor in adults and has a poor prognosis. Complex genetic alterations and the protective effect of the blood-brain barrier (BBB) have so far hampered effective treatment. Here, we investigated the cytotoxic effects of heat shock protein 90 (HSP90) inhibitors, geldanamycin (GDN) and 17-allylamino-17-demethoxygeldanamycin (17-AAG, tanespimycin), in a panel of glioma tumor cell lines with various genetic alterations. We also assessed the ability of the main drug transporters, ABCB1 and ABCG2, to efflux GDN and 17-AAG. We found that GDN and 17-AAG induced extensive cell death with the morphological and biochemical hallmarks of apoptosis in all studied glioma cell lines at sub-micro-molar and nanomolar concentrations. Moderate efflux efficacy of GDN and 17-AAG mediated by ABCB1 was observed. There was an insignificant and low efflux efficacy of GDN and 17-AAG mediated by ABCG2. Conclusion: GDN and 17-AAG, in particular, exhibited strong proapoptotic effects in glioma tumor cell lines irrespective of genetic alterations. GDN and 17-AAG appeared to be weak substrates of ABCB1 and ABCG2. Therefore, the BBB would compromise their cytotoxic effects only partially. We hypothesize that GBM patients may benefit from 17-AAG either as a single agent or in combination with other drugs.
- Publikační typ
- časopisecké články MeSH
Lysosomal sequestration of anticancer therapeutics lowers their cytotoxic potential, reduces drug availability at target sites, and contributes to cancer resistance. Only recently has it been shown that lysosomal sequestration of weak base drugs induces lysosomal biogenesis mediated by activation of transcription factor EB (TFEB) which, in turn, enhances their accumulation capacity, thereby increasing resistance to these drugs. Here, we addressed the question of whether lysosomal biogenesis is the only mechanism that increases lysosomal sequestration capacity. We found that lysosomal sequestration of some tyrosine kinase inhibitors (TKIs), gefitinib (GF) and imatinib (IM), induced expansion of the lysosomal compartment. However, an expression analysis of lysosomal genes, including lysosome-associated membrane proteins 1, 2 (LAMP1, LAMP2), vacuolar ATPase subunit B2 (ATP6V1B2), acid phosphatase (ACP), and galactosidase beta (GLB) controlled by TFEB, did not reveal increased expression. Instead, we found that both studied TKIs, GF and IM, induced lysosomal fusion which was dependent on nicotinic acid adenine dinucleotide phosphate (NAADP) mediated Ca2+signaling. A theoretical analysis revealed that lysosomal fusion is sufficient to explain the enlargement of lysosomal sequestration capacity. In conclusion, we demonstrated that extracellular TKIs, GF and IM, induced NAADP/Ca2+ mediated lysosomal fusion, leading to enlargement of the lysosomal compartment with significantly increased sequestration capacity for these drugs without apparent lysosomal biogenesis.
- MeSH
- biogeneze organel MeSH
- buňky K562 MeSH
- chemorezistence účinky léků MeSH
- gefitinib farmakologie MeSH
- imatinib mesylát farmakologie MeSH
- lidé MeSH
- lyzozomy účinky léků metabolismus MeSH
- nádorové buněčné linie MeSH
- protinádorové látky farmakologie MeSH
- signální transdukce účinky léků MeSH
- transkripční faktory BHLH-Zip účinky léků metabolismus MeSH
- tyrosinkinasy antagonisté a inhibitory MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
The Lysosomal sequestration of weak-base anticancer drugs is one putative mechanism for resistance to chemotherapy but it has never been directly proven. We addressed the question of whether the lysosomal sequestration of tyrosine kinase inhibitors (TKIs) itself contributes to the drug resistance in vitro. Our analysis indicates that lysosomal sequestration of an anticancer drug can significantly reduce the concentration at target sites, only when it simultaneously decreases its extracellular concentration due to equilibrium, since uncharged forms of weak-base drugs freely diffuse across cellular membranes. Even though the studied TKIs, including imatinib, nilotinib, and dasatinib, were extensively accumulated in the lysosomes of cancer cells, their sequestration was insufficient to substantially reduce the extracellular drug concentration. Lysosomal accumulation of TKIs also failed to affect the Bcr-Abl signaling. Cell pre-treatment with sunitinib significantly enhanced the lysosomal accumulation of the TKIs used; however, without apparent lysosomal biogenesis. Importantly, even increased lysosomal sequestration of TKIs neither decreased their extracellular concentrations nor affected the sensitivity of Bcr-Abl to TKIs. In conclusion, our results clearly show that the lysosomal sequestration of TKIs failed to change their concentrations at target sites, and thus, can hardly contribute to drug resistance in vitro.
- MeSH
- buňky K562 MeSH
- chemorezistence * MeSH
- extracelulární prostor účinky léků metabolismus MeSH
- inhibitory proteinkinas farmakologie MeSH
- lidé MeSH
- lyzozomy účinky léků metabolismus MeSH
- sunitinib farmakologie MeSH
- tyrosinkinasy metabolismus MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
The interaction between ABCB1 transporter and its substrates takes place in cell membranes but the available data precludes quantitative analysis of the interaction between transporter and substrate molecules. Further, the amount of transporter is usually expressed as a number of ABCB1 molecules per cell. In contrast, the substrate concentration in cell membranes is estimated by determination of substrate-lipid partition coefficient, as examples. In this study, we demonstrate an approach, which enables us to estimate the concentration of ABCB1 molecules within plasma membranes. For this purpose, human leukemia K562 cells with varying expression levels of ABCB1 were used: drug selected K562/Dox and K562/HHT cells with very high transporter expression, and K562/DoxDR2, K562/DoxDR1, and K562/DoxDR05 cells with gradually decreased expression of ABCB1 derived from K562/Dox cells using RNA interference technology. First, we determined the absolute amount of ABCB1 in cell lysates using immunoblotting and recombinant ABCB1 as a standard. We then determined the relative portion of transporter residing in the plasma membrane using immunohistochemistry in nonpermeabilized and permeabilized cells. These results enabled us to estimate the concentration of ABCB1 in the plasma membrane in resistant cells. The ABCB1 concentrations in the plasma membrane of drug selected K562/Dox and K562/HHT cells containing the highest amount of transporter reached millimolar levels. Concentrations of ABCB1 in the plasma membrane of resistant K562/DoxDR2, K562/DoxDR1, and K562/DoxDR05 cells with lower transporter expression were proportionally decreased.
- MeSH
- buněčná membrána metabolismus MeSH
- buňky K562 MeSH
- fluorescenční protilátková technika MeSH
- lidé MeSH
- P-glykoproteiny genetika metabolismus MeSH
- RNA interference MeSH
- viabilita buněk genetika fyziologie MeSH
- western blotting MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
The synthetic curcumin analogue, 3,5-bis[(2-fluorophenyl)methylene]-4-piperidinone (EF-24), suppresses NF-κB activity and exhibits antiproliferative effects against a variety of cancer cells in vitro. Recently, it was reported that EF-24-induced apoptosis was mediated by a redox-dependent mechanism. Here, we studied the effects of N-acetylcysteine (NAC) on EF-24-induced cell death. We also addressed the question of whether the main drug transporters, ABCB1 and ABCG2, affect the cytotoxic of EF-24. We observed that EF-24 induced cell death with apoptotic hallmarks in human leukemia K562 cells. Importantly, the loss of cell viability was preceded by production of reactive oxygen species (ROS), and by a decrease of reduced glutathione (GSH). However, neither ROS production nor the decrease in GSH predominantly contributed to the EF-24-induced cell death. We found that EF-24 formed an adduct with GSH, which is likely the mechanism contributing to the decrease of GSH. Although NAC abrogated ROS production, decreased GSH and prevented cell death, its protective effect was mainly due to a rapid conversion of intra- and extra-cellular EF-24 into the EF-24-NAC adduct without cytotoxic effects. Furthermore, we found that neither overexpression of ABCB1 nor ABCG2 reduced the antiproliferative effects of EF-24. In conclusion, a redox-dependent-mediated mechanism only marginally contributes to the EF-24-induced apoptosis in K562 cells. The main mechanism of NAC protection against EF-24-induced apoptosis is conversion of cytotoxic EF-24 into the noncytotoxic EF-24-NAC adduct. Neither ABCB1 nor ABCG2 mediated resistance to EF-24.
- MeSH
- ABC transportér z rodiny G, člen 2 genetika metabolismus MeSH
- acetylcystein metabolismus MeSH
- apoptóza účinky léků MeSH
- benzylidenové deriváty farmakologie MeSH
- glutathion metabolismus MeSH
- leukemie metabolismus MeSH
- lidé MeSH
- nádorové buněčné linie MeSH
- nádorové proteiny genetika metabolismus MeSH
- oxidační stres * MeSH
- P-glykoproteiny genetika metabolismus MeSH
- piperidony farmakologie MeSH
- protinádorové látky farmakologie MeSH
- reaktivní formy kyslíku metabolismus MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
CONTEXT: The preparation of liquisolid systems (LSS) represents a promising method for enhancing a dissolution rate and bioavailability of poorly soluble drugs. The release of the drug from LSS tablets is affected by many factors, including the disintegration time. OBJECTIVE: The evaluation of differences among LSS containing varying amounts and types of commercially used superdisintegrants (Kollidon® CL-F, Vivasol® and Explotab®). MATERIALS AND METHODS: LSS were prepared by spraying rosuvastatin solution onto Neusilin® US2 and further processing into tablets. Varying amounts of superdisintegrants were used and the differences among LSS were evaluated. The multiple scatter plot method was used to visualize the relationships within the obtained data. RESULTS AND DISCUSSION: All disintegrants do not showed negative effect on the flow properties of powder blends. The type and concentration of superdisintegrant had an impact on the disintegration time and dissolution profiles of tablets. Tablets with Explotab® showed the longest disintegration time and the smallest amount of released drug. Fastest disintegration and dissolution rate were observed in tablets containing Kollidon® CL-F (≥2.5% w/w). Also tablets with Vivasol® (2.5-4.0% w/w) showed fast disintegration and complete drug release. CONCLUSION: Kollidon® CL-F and Vivasol® in concentration ≥2.5% are suitable superdisintegrants for LSS with enhanced release of drug.
- MeSH
- anticholesteremika aplikace a dávkování chemie MeSH
- farmaceutické pomocné látky chemie MeSH
- povidon chemie MeSH
- příprava léků MeSH
- rosuvastatin kalcium aplikace a dávkování chemie MeSH
- rozpustnost MeSH
- silikáty chemie MeSH
- škrob analogy a deriváty chemie MeSH
- sloučeniny hliníku chemie MeSH
- sloučeniny hořčíku chemie MeSH
- tablety chemie MeSH
- uvolňování léčiv MeSH
- Publikační typ
- časopisecké články MeSH
Recently, it has been suggested that imatinib (IM) and nilotinib (NIL) could be studied beyond their original application, as inhibitors of the drug efflux pump ABCB1 (P-glycoprotein, MDR1). Since the reversal of ABCB1-mediated resistance has never been successfully demonstrated in the clinic, we addressed the question of whether IM and NIL may actually serve as efficient inhibitors of ABCB1. Here we define an efficient inhibitor as a compound that achieves full (90-100%) reversal of drug efflux at a concentration that does not exhibit significant off-target toxicity in vitro. In this study, human leukemia K562 cells expressing various levels of ABCB1 were used. We observed that cells expressing higher ABCB1 levels required higher concentrations of IM and NIL to achieve full reversal of drug efflux. Among the well-known ABCB1 inhibitors, a similar effect was found for cyclosporin A (CsA) but not for zosuquidar. IM was efficient only in cells with the low and moderate ABCB1 expression at high concentrations that were cytotoxic in the absence of Bcr-Abl. In contrast, NIL was as efficient an inhibitor of ABCB1 as CsA. Low and moderate expression levels of ABCB1 could be efficiently inhibited by NIL concentrations without cytotoxic effects in the absence of Bcr-Abl. However, high expression levels of ABCB1 required higher NIL concentrations with off-target cytotoxic effects. In conclusion, application of NIL, but not of IM, in clinics is promising, however, only in cells with low ABCB1 expression levels. We hypothesize that some patients may benefit from an inhibitor exhibiting an ABCB1 expression-dependent effect.
- MeSH
- imatinib mesylát farmakologie MeSH
- lidé MeSH
- nádorové buňky kultivované MeSH
- P-glykoproteiny antagonisté a inhibitory metabolismus MeSH
- proliferace buněk účinky léků MeSH
- pyrimidiny farmakologie MeSH
- viabilita buněk účinky léků MeSH
- vztah mezi dávkou a účinkem léčiva MeSH
- vztahy mezi strukturou a aktivitou MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
