ABSTRACT
Generation 4 of polyamidoamine dendrimer (G4-PAMAM) has several biological effects due to its tridimensional globular structure, repetitive branched amides, tertiary amines, and amino-terminal subunit groups liked to a common core. G4-PAMAM is cytotoxic due to its positive charges. However, its cytotoxicity could increase in cancer cells due to the excessive intracellular negative charges in these cells. Furthermore, this work reports G4-PAMAM chemical structural characterization using UHPLC-QTOF-MS/MS (LC-MS) by electrospray ionization to measure its population according to its positive charges. Additionally, the antiproliferative effects and intracellular localization were explored in the HMC-1 and K-562 cell lines by confocal microscopy. The LC-MS results show that G4-PAMAM generated multivalent mass spectrum values, and its protonated terminal amino groups produced numerous positive charges, which allowed us to determine its exact mass despite having a high molecular weight. Additionally, G4-PAMAM showed antiproliferative activity in the HMC-1 tumor cell line after 24 h (IC50 = 16.97 µM), 48 h (IC50 = 7.02 µM) and 72 h (IC50 = 5.98 µM) and in the K-562 cell line after 24 h (IC50 = 15.14 µM), 48 h (IC50 = 14.18 µM) and 72 h (IC50 = 9.91 µM). Finally, our results showed that the G4-PAMAM dendrimers were located in the cytoplasm and nucleus in both tumor cell lines studied.
Subject(s)
Dendrimers/pharmacology , Leukemia/drug therapy , Leukemia/metabolism , Nylons/pharmacology , Antineoplastic Agents/analysis , Antineoplastic Agents/pharmacokinetics , Antineoplastic Agents/pharmacology , Cell Line, Tumor , Chromatography, Liquid , Dendrimers/analysis , Dendrimers/pharmacokinetics , Drug Screening Assays, Antitumor/methods , Humans , Inhibitory Concentration 50 , Intracellular Space/drug effects , Intracellular Space/metabolism , K562 Cells , Leukemia/pathology , Nylons/analysis , Nylons/pharmacokinetics , Spectrometry, Mass, Electrospray Ionization , Tandem Mass Spectrometry , Tissue DistributionABSTRACT
ABSTRACT The surface of flat-sheet nylon membranes was modified using bisoxirane as the spacer and polyvinyl alcohol as the coating polymer. The amino acid histidine was explored as a ligand for endotoxins, aiming at its application for endotoxin removal from aqueous solutions. Characterization of the membrane adsorber, analysis of the depyrogenation procedures and the evaluation of endotoxin removal efficiency in static mode are discussed. Ligand density of the membranes was around 7 mg/g dry membrane, allowing removal of up to 65% of the endotoxins. The performance of the membrane adsorber prepared using nylon coated with polyvinyl alcohol and containing histidine as the ligand proved superior to other membrane adsorbers reported in the literature. The lack of endotoxin adsorption on nylon membranes without histidine confirmed that endotoxin removal was due to the presence of the ligand at the membrane surface. Modified membranes were highly stable, exhibiting a lifespan of approximately thirty months.
RESUMO A superfície de membranas planas de nylon foi modificada utilizando-se bisoxirano como espaçador e poli(álcool vinílico) para recobrimento das membranas. O aminoácido histidina foi utilizado como ligante para endotoxinas, visando à sua aplicação na remoção de endotoxinas a partir de soluções aquosas. São discutidas as etapas de caracterização do adsorvedor com membranas, análise do procedimento de despirogenização e avaliação da eficiência de remoção em modo estático. A densidade de ligantes nas membranas foi em torno de 7 mg/g membrana (massa seca), permitindo uma remoção de endotoxinas de até 65%. O desempenho das membranas preparadas com nylon e recobertas com poli(álcool vinílico) contendo histidina como ligante foi superior ao de outros adsorvedores com membranas descritos na literatura. A ausência de adsorção de endotoxinas em membranas sem histidina confirma que a remoção das endotoxinas deve-se exclusivamente à presença do ligante na superfície da membrana. As membranas modificadas mostraram-se bastante estáveis, exibindo um tempo de vida superior a 30 dias.