Cationic and amphiphilic polymers are known to exert broad-spectrum antibacterial activity by a putative mechanism of membrane disruption. Typically, nonspecific binding to hydrophobic components of the complex biological milieu, such as globular proteins, is considered a deterrent to the successful application of such polymers. To evaluate the extent to which serum deactivates antibacterial polymethacrylates, we compared their minimum inhibitory concentrations in the presence and absence of fetal bovine serum. Surprisingly, we discovered that the addition of fetal bovine serum (FBS) to the assay media in fact enhances the antimicrobial activity of polymers against Gram-positive bacteria S. aureus, whereas the opposite is the case for Gram-negative E. coli. Here, we present these unexpected trends and develop a hypothesis to potentially explain this unusual phenomenon.

• MeSH
• antibakteriální látky farmakologie   MeSH
• bakteriální léková rezistence účinky léků   MeSH
• Escherichia coli účinky léků   MeSH
• hydrofobní a hydrofilní interakce MeSH
• kyseliny polymethakrylové farmakologie   MeSH
• mikrobiální testy citlivosti MeSH
• sérový albumin hovězí farmakologie   MeSH
• Staphylococcus aureus účinky léků   MeSH
• synergismus léků MeSH
• Publikační typ
• časopisecké články MeSH

The aim of the present study was to investigate the suitability of insoluble Eudragit® water dispersions (NE, NM, RL, and RS) for direct high-shear granulation of very soluble levetiracetam in order to decrease its burst effect from HPMC K100M matrices. The process characteristics, ss-NMR analysis, in vitro dissolution behavior, drug release mechanism and kinetics, texture profile analysis of the gel layer, and PCA analysis were explored. An application of water dispersions directly on levetiracetam was feasible only in a multistep process. All prepared formulations exhibited a 12-hour sustained release profile characterized by a reduced burst effect in a concentration-dependent manner. No effect on swelling extent of HPMC K100M was observed in the presence of Eudragit®. Contrary, higher rigidity of formed gel layer was observed using combination of HPMC and Eudragit®. Not only the type and concentration of Eudragit®, but also the presence of the surfactant in water dispersions played a key role in the dissolution characteristics. The dissolution profile close to zero-order kinetic was achieved from the sample containing levetiracetam directly granulated by the water dispersion of Eudragit® NE (5% of solid polymer per tablet) with a relatively high amount of surfactant nonoxynol 100 (1.5%). The initial burst release of drug was reduced to 8.04% in 30 min (a 64.2% decrease) while the total amount of the released drug was retained (97.02%).

• MeSH
• deriváty hypromelózy * chemie   farmakokinetika   farmakologie   MeSH
• kyseliny polymethakrylové * chemie   farmakokinetika   farmakologie   MeSH
• laktosa analogy a deriváty   chemie   farmakokinetika   farmakologie   MeSH
• léky s prodlouženým účinkem farmakokinetika   farmakologie   MeSH
• methylcelulosa analogy a deriváty   chemie   farmakokinetika   farmakologie   MeSH
• nonoxynol * chemie   farmakokinetika   farmakologie   MeSH
• uvolňování léčiv MeSH
• Publikační typ
• časopisecké články MeSH

We have investigated the effects of low-frequency pulsed electromagnetic field (LF-EMF) produced by BEMER device on experimental mouse T-cell lymphoma EL4 growing on conventional and/or athymic (nude) mice. Exposure to EMF-BEMER slowed down the growth of tumor mass and prolonged the survival of experimental animals. The effect was more pronounced in immuno-compromised nude mice compared to conventional ones. Acceleration of tumor growth was never observed. No measurable levels of Hsp 70 or increased levels of specific anti-EL4 antibodies were detected in the serum taken from experimental mice before and at different intervals during the experiment, i.e. before solid tumor appeared, at the time of its aggressive growth, and at the terminal stage of the disease. A significant synergizing antitumor effect was seen when EL4 tumor-bearing mice were simultaneously exposed to EMF-BEMER and treated with suboptimal dose of synthetic HPMA copolymer-based doxorubicin, DOX(HYD)-HPMA. Such a combination may be especially useful for heavily treated patients suffering from advanced tumor and requiring additional aggressive chemotherapy which, however, at that time could represent almost life-threatening way of medication.

• MeSH
• antibiotika antitumorózní aplikace a dávkování   farmakologie   MeSH
• doxorubicin aplikace a dávkování   analogy a deriváty   farmakologie   MeSH
• elektromagnetická pole MeSH
• hostitel s imunodeficiencí MeSH
• kombinovaná terapie MeSH
• kyseliny polymethakrylové aplikace a dávkování   farmakologie   MeSH
• lymfom T-buněčný patologie   terapie   MeSH
• míra přežití MeSH
• myši inbrední C57BL MeSH
• myši nahé MeSH
• myši MeSH
• proteiny tepelného šoku HSP70 metabolismus   MeSH
• vztah mezi dávkou a účinkem léčiva MeSH
• zvířata MeSH
• Check Tag
• myši MeSH
• ženské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Radioactive decay of some radionuclides produces a shower of Auger electrons, potent ionizing radiation within a very short range in living tissue (typically ca. 100 nm). Therefore, they must be brought to DNA-containing cell compartments and preferentially directly to DNA to be fully biologically effective. They may be used for a triple-targeting approach (first targeting, polymer-based system targeting into tumor tissue due to EPR effect; second targeting, pH-controlled release of intercalator-bound Auger electron emitter in slightly acidic tumor tissue or endosome; third targeting, into DNA in cell nucleus by the intercalator) minimizing radiation burden of healthy tissues. We describe a first system of this type, an ellipticine derivative-bound iodine-125 attached to hydrazide moieties containing poly[N-(2-hydroxypropyl)methacrylamide]. The system is stable at pH 7.4 (0% intercalator released after 24 h incubation), while iodine-containing biologically active intercalator is released upon decrease of pH (25% intercalator released after 24 h incubation at pH 5.0-model of late endosomes). Both 2-N-(2-oxobutyl)-9-iodoellipticinium bromide and the noniodinated 2-N-(2-oxobutyl)ellipticinium bromide are potent intercalators, as proven by direct titration with DNA and ethidium displacement assay, and readily penetrate into cell nuclei, as proven by confocal microscopy. They retain chemotherapeutical antiproliferative properties of ellipticine against Raji, EL-4, and 4T1cells with IC(50) in the range 0.27-8.8 μmol/L. Polymer conjugate of 2-N-(2-oxobutyl)-9-iodoellipticinium bromide is internalized into endosomes, releases active drug, possesses cytotoxic activity, and the drug accumulates in cell nuclei.

• MeSH
• buněčné jádro účinky léků   metabolismus   MeSH
• DNA chemie   MeSH
• elektrony MeSH
• elipticiny chemie   farmakologie   MeSH
• hydraziny chemie   MeSH
• koncentrace vodíkových iontů MeSH
• kyseliny polymethakrylové chemická syntéza   chemie   farmakologie   MeSH
• lidé MeSH
• molekulární struktura MeSH
• myši MeSH
• nádorové buněčné linie MeSH
• organely chemie   účinky léků   MeSH
• radioizotopy jodu MeSH
• stereoizomerie MeSH
• tkáňová distribuce MeSH
• viabilita buněk účinky léků   MeSH
• vztah mezi dávkou a účinkem léčiva MeSH
• vztahy mezi strukturou a aktivitou MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

PURPOSE: In vivo efficacy and safety of HPMA-based copolymers armed with doxorubicin via a spacer containing pH-sensitive linkage that can be prepared within a broad range of attached drug contents (1) was tested in murine tumor models. METHODS: Mice bearing T cell lymphoma EL4 or B cell lymphoma 38C13 were treated with a single dose of the conjugate (15, 25, and 75 mg Dox eq./kg i.v.) in a therapeutic regime. Anti-tumor resistance of the cured animals was proved by a second challenge with a lethal dose of tumor cells without additional treatment. RESULTS: The content of drug bound to the polymer is an important parameter in relation to the conjugate therapeutic efficacy. The best anti-tumor effects were produced by conjugates with 10 - 13 wt% of bound doxorubicin. Free doxorubicin up to 4.6% relative to total drug content had no impact on the treatment efficacy and acute toxicity. The conjugates induced a complete cure of mice and regular treatment-dependent development of specific anti-tumor resistance. No myelosuppression or organ damage was observed. CONCLUSIONS: A well-defined HPMA copolymer-doxorubicin conjugate with pH-sensitive drug release is a good candidate for clinical trials as it has remarkable anti-tumor efficacy and a favorable safety profile.

• MeSH
• antibiotika antitumorózní farmakokinetika   farmakologie   MeSH
• doxorubicin analogy a deriváty   chemická syntéza   farmakokinetika   farmakologie   MeSH
• imunomodulace účinky léků   MeSH
• koncentrace vodíkových iontů MeSH
• kyseliny polymethakrylové chemická syntéza   farmakokinetika   farmakologie   MeSH
• myši MeSH
• nádorové buněčné linie MeSH
• nosiče léků chemická syntéza   farmakokinetika   farmakologie   MeSH
• polymery chemická syntéza   farmakokinetika   farmakologie   MeSH
• proliferace buněk účinky léků   MeSH
• xenogenní modely - testy antitumorózní aktivity MeSH
• zvířata MeSH
• Check Tag
• mužské pohlaví MeSH
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

To avoid the side effects of the anti-cancer drug doxorubicin (Dox), we conjugated this drug to a N-(2-hydroxypropyl)methacrylamide (HPMA) copolymer backbone. Dox was conjugated via an amide bond (Dox-HPMA(AM), PK1) or a hydrazone pH-sensitive bond (Dox-HPMA(HYD)). In contrast to Dox and Dox-HPMA(HYD), Dox-HPMA(AM) accumulates within the cell's intracellular membranes, including those of the Golgi complex and endoplasmic reticulum, both involved in protein glycosylation. Flow cytometry was used to determine lectin binding and cell death, immunoblot to characterize the presence of CD7, CD43, CD44, and CD45, and high-performance anion exchange chromatography with pulsed amperometric detector analysis for characterization of plasma membrane saccharide composition. Incubation of EL4 cells with Dox-HPMA(AM) conjugate, in contrast to Dox or Dox-HPMA(HYD), increased the amounts of membrane surface-associated glycoproteins, as well as saccharide moieties recognized by peanut agglutinin, Erythrina cristagalli, or galectin-1 lectins. Only Dox-HPMA(AM) increased expression of the highly glycosylated membrane glycoprotein CD43, while expression of others (CD7, CD44, and CD45) was unaffected. The binding sites for galectin-1 are present on CD43 molecule. Furthermore, we present that EL4 treated with Dox-HPMA(AM) possesses increased sensitivity to galectin-1-induced apoptosis. In this study, we demonstrate that Dox-HPMA(AM) treatment changes glycosylation of the EL4 T cell lymphoma surface and sensitizes the cells to galectin-1-induced apoptosis.

• MeSH
• amidy chemie   MeSH
• antibiotika antitumorózní farmakologie   MeSH
• antigeny CD43 metabolismus   MeSH
• apoptóza MeSH
• doxorubicin analogy a deriváty   farmakologie   MeSH
• endoplazmatické retikulum metabolismus   MeSH
• galektin 1 metabolismus   MeSH
• glykosylace MeSH
• Golgiho aparát metabolismus   MeSH
• kyseliny polymethakrylové farmakologie   MeSH
• lymfom T-buněčný farmakoterapie   metabolismus   patologie   MeSH
• myši MeSH
• nádorové buněčné linie účinky léků   MeSH
• nosiče léků MeSH
• proliferace buněk MeSH
• průtoková cytometrie MeSH
• western blotting MeSH
• zvířata MeSH
• Check Tag
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

BALB/c mice bearing syngeneic BCL1 leukemia, a mouse model of human chronic lymphocytic leukemia, were treated with polymer-bound doxorubicin conjugate targeted with BCL1-specific monoclonal antibody. Such treatment can cure up to 100% of mice and the cured mice show long-lasting resistance to BCL1 leukemia. We show that both CD4+ and CD8+ T cells are required for establishment of the resistance, but only CD8+ T cells are necessary for its maintenance. BCL1 cells express MHC class I and II and also costimulatory molecules CD80 and CD86, which can aid eliciting of antitumor response. On the other hand, BCL1 cells also use several immunoescape mechanisms, such as expression of PD-L1, PD-L2, and interleukin-10. BCL1 cells thus can be recognized by BCL1-specific T cells, but instead of effective priming, such T cells are anergized or deleted by apoptosis. Moreover, BCL1 leukemia progression is accompanied by robust expansion of CD4+CD25+Foxp3+ regulatory T (Treg) cells. Although it has been shown that depletion of Treg cells in tumor-bearing mice can retard tumor growth, direct evidence that expansion of Treg cells can promote tumor growth was lacking. In this study, we provide first direct evidence that expanded Treg cells can indeed promote tumor progression by using mice with selectively expanded Treg cells before inoculation of BCL1 leukemia. Finally, we have also shown that elimination of some immunoescape mechanism (e.g., deletion of Treg) can significantly improve the therapeutic outcome of chemotherapy.

• MeSH
• antibiotika antitumorózní farmakologie   MeSH
• CD8-pozitivní T-lymfocyty imunologie   MeSH
• doxorubicin analogy a deriváty   farmakologie   MeSH
• imunokonjugáty farmakologie   imunologie   MeSH
• kyseliny polymethakrylové farmakologie   MeSH
• leukemie B-buněčná farmakoterapie   imunologie   MeSH
• monoklonální protilátky imunologie   MeSH
• myši inbrední BALB C MeSH
• myši MeSH
• regulační T-lymfocyty imunologie   MeSH
• únik nádoru z imunitní kontroly imunologie   účinky léků   MeSH
• zvířata MeSH
• Check Tag
• myši MeSH
• ženské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• práce podpořená grantem MeSH

Various conjugates of anticancer drug doxorubicin (Dox) covalently bound by the hydrolytically degradable hydrazone bond to the drug carrier based on N-(2-hydroxypropyl)methacrylamide (HPMA) copolymers were synthesised. Structure of the conjugates differed in the type and the content of hydrophobic substituent (dodecyl, oleic acid and cholesterol moieties) introduced into the polymer structure. In aqueous solutions the conjugates self-assembled into high-molecular-weight supramolecular structures, such as polymeric micelles or stable hydrophilic nanoparticles 13-37 nm in diameter, depending on the type and the content of hydrophobic substituents. Treatment of mice bearing EL-4 T cell lymphoma with the conjugates in the therapeutic regime of drug administration (i.v.) resulted in significant tumour regression with up to 100% of long-term survivors, depending on the dose and the detailed structure of the carrier. The nanoparticles formed by the conjugate bearing cholesterol moiety exhibited prolonged blood circulation and enhanced tumour accumulation indicating an important role of the EPR effect in excellent anticancer activity of the conjugate.

• MeSH
• antibiotika antitumorózní farmakokinetika   farmakologie   chemie   MeSH
• doxorubicin analogy a deriváty   farmakokinetika   farmakologie   chemie   MeSH
• financování organizované MeSH
• hydrofobní a hydrofilní interakce MeSH
• kyseliny polymethakrylové farmakokinetika   farmakologie   chemie   MeSH
• lidé MeSH
• methakryláty farmakokinetika   farmakologie   chemie   MeSH
• myši inbrední C57BL MeSH
• myši MeSH
• nádorové buněčné linie MeSH
• nádory farmakoterapie   metabolismus   MeSH
• nosiče léků farmakokinetika   farmakologie   chemie   MeSH
• proliferace buněk účinky léků   MeSH
• transplantace nádorů MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• myši MeSH
• zvířata MeSH

A systematic study was designed to elucidate differences in cytostatic activity in vitro between HPMA-based doxorubicin conjugates synthesized using different polymerization techniques and differing in peptidyl side chain. A polymer-drug conjugate containing doxorubicin (DOX) bound to HPMA copolymer backbone through the enzymaticaly non-cleavable sequence GlyGly shows low but significant cytotoxicity in vitro in seven cancer cell lines of mouse (EL4, 38C13, 3T3, BCL1) and human (SW620, Raji, Jurkat) origin. The low cytotoxicity can be considerably increased by the presence of additional drug-free GlyPheLeuGly side chains. P1 conjugate, i.e. non-targeted HPMA copolymer bearing doxorubicin bound via a biodegradable GlyPheLeuGly sequence, synthesized by direct copolymerization of HPMA with monomeric doxorubicin and thus without additional drug-free GlyPheLeuGly sequences is less effective compared to PK1 synthesized by polymer analogous reaction and thus containing extra drug-free GlyPheLeuGly sequences. Significant activity-enhancing effect was not seen with other amino acid/oligopeptide sequences (e.g., Gly or GlyGly). The activity-enhancing effect of GlyPheLeuGly sequences is more obvious in the conjugate containing doxorubicin bound to HPMA through GlyGly sequence. Derivatization of the terminal carboxyl group of the extra GlyPheLeuGly side chains (amide, N-substituted amide, free carboxyl) does not significantly influence the cytotoxicity of the conjugates. The presence of the GlyPheLeuGly sequence in the conjugate structure increases its rate of intracellular accumulation. Normal cells (Balb/c splenocytes) accumulate less polymer-doxorubicin conjugate compared to cancer cells (T cell lymphoma EL4, B cell lymphoma Raji and T cell leukemia JURKAT).

• MeSH
• antibiotika antitumorózní farmakologie   MeSH
• apoptóza MeSH
• doxorubicin farmakologie   MeSH
• financování organizované MeSH
• kultivované buňky MeSH
• kyseliny polymethakrylové farmakologie   MeSH
• lidé MeSH
• methakryláty chemie   MeSH
• myši inbrední BALB C MeSH
• myši MeSH
• nádorové buněčné linie MeSH
• nekróza MeSH
• oligopeptidy farmakologie   chemie   MeSH
• proliferace buněk účinky léků   MeSH
• slezina cytologie   MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• myši MeSH
• zvířata MeSH

Synthesis and preliminary anticancer activity of new star-shaped immunoglobulin-containing polymer-doxorubicin (DOX) conjugates were investigated. The polymer precursors used for the synthesis of immunoglobulin-polymer-drug conjugates are based on N-(2-hydroxypropyl)methacrylamide (HPMA) copolymers, the anticancer drug DOX is attached to the immunoglobulin-modified polymer via a pH-sensitive hydrazone linkage. Such polymer-DOX conjugates are stable in aqueous solution at pH 7.4 (pH of blood plasma) and the drug is released in mildly acid environment at pH 5-5.5 (pH in endosomes or lysosomes of target cells). Semitelechelic copolymer chains are linked to the immunoglobulin via one-point attachment to avoid branching of the conjugate observed in our earlier studied systems. The cytostatic activity of the conjugates tested on several cancer cell lines was similar to that of free DOX.HCl and correlated with the sensitivity of a particular cell line to DOX. The star-shaped conjugates containing immunoglobulin showed a significantly higher antitumor activity in vivo than immunoglobulin-free non-targeted polymer conjugates when tested in mice bearing EL4 T-cell lymphoma.

• MeSH
• antibiotika antitumorózní aplikace a dávkování   farmakologie   chemie   MeSH
• doxorubicin analogy a deriváty   aplikace a dávkování   farmakologie   chemie   MeSH
• financování organizované MeSH
• imunoglobuliny aplikace a dávkování   chemie   MeSH
• imunokonjugáty aplikace a dávkování   chemie   MeSH
• kyseliny polymethakrylové aplikace a dávkování   farmakologie   chemie   MeSH
• léky antitumorózní - screeningové testy MeSH
• lidé MeSH
• lymfom T-buněčný farmakoterapie   MeSH
• myši inbrední C57BL MeSH
• myši MeSH
• nádorové buněčné linie MeSH
• nosiče léků aplikace a dávkování   chemická syntéza   chemie   MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• mužské pohlaví MeSH
• myši MeSH
• zvířata MeSH