One obstacle to the successful delivery of nanodrugs into solid tumors is the heterogeneity of an enhanced permeability and retention (EPR) effect as a result of occluded or embolized tumor blood vessels. Therefore, the augmentation of the EPR effect is critical for satisfactory anticancer nanomedicine. In this study, we focused on one vascular mediator involved in the EPR effect, carbon monoxide (CO), and utilized two CO generating agents, one is an extrinsic CO donor (SMA/CORM2 micelle) and another is an inducer of endogenous CO generation via heme oxygenase-1 (HO-1) induction that is carried out using pegylated hemin. Both agents generated CO selectively in solid tumors, which resulted in an enhanced EPR effect and a two- to three-folds increased tumor accumulation of nanodrugs. An increase in drug accumulation in the normal tissue did not occur with the treatment of CO generators. In vivo imaging also clearly indicated a more intensified fluorescence of macromolecular nanoprobe in solid tumors when combined with these CO generators. Consequently, the combination of CO generators with anticancer nanodrugs resulted in an increased anticancer effect in the different transplanted solid tumor models. These findings strongly warrant the potential application of these CO generators as EPR enhancers in order to enhance tumor detection and therapy using nanodrugs.

• Klíčová slova
• EPR effect, PDT, carbon monoxide, nanomedicine, nanoprobe,
• Publikační typ
• časopisecké články MeSH

The Enhanced Permeability and Retention (EPR) effect is extensively used in drug delivery research. Taking into account that EPR is a highly variable phenomenon, we have here set out to evaluate if contrast-enhanced functional ultrasound (ceUS) imaging can be employed to characterize EPR-mediated passive drug targeting to tumors. Using standard fluorescence molecular tomography (FMT) and two different protocols for hybrid computed tomography-fluorescence molecular tomography (CT-FMT), the tumor accumulation of a ~10 nm-sized near-infrared-fluorophore-labeled polymeric drug carrier (pHPMA-Dy750) was evaluated in CT26 tumor-bearing mice. In the same set of animals, two different ceUS techniques (2D MIOT and 3D B-mode imaging) were employed to assess tumor vascularization. Subsequently, the degree of tumor vascularization was correlated with the degree of EPR-mediated drug targeting. Depending on the optical imaging protocol used, the tumor accumulation of the polymeric drug carrier ranged from 5 to 12% of the injected dose. The degree of tumor vascularization, determined using ceUS, varied from 4 to 11%. For both hybrid CT-FMT protocols, a good correlation between the degree of tumor vascularization and the degree of tumor accumulation was observed, within the case of reconstructed CT-FMT, correlation coefficients of ~0.8 and p-values of <0.02. These findings indicate that ceUS can be used to characterize and predict EPR, and potentially also to pre-select patients likely to respond to passively tumor-targeted nanomedicine treatments.

• Klíčová slova
• Cancer, Drug targeting, EPR, HPMA, Nanomedicine, Theranostics,
• MeSH
• akrylamidy aplikace a dávkování   MeSH
• enbukrylát MeSH
• kontrastní látky aplikace a dávkování   MeSH
• krevní objem MeSH
• mikrobubliny MeSH
• myši nahé MeSH
• nádorové buněčné linie MeSH
• nádory krevní zásobení   diagnostické zobrazování   metabolismus   patofyziologie   MeSH
• permeabilita MeSH
• regionální krevní průtok MeSH
• systémy cílené aplikace léků * MeSH
• tomografie metody   MeSH
• ultrasonografie MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• akrylamidy MeSH
• enbukrylát MeSH
• kontrastní látky MeSH

Tumors are characterized by leaky blood vessels, and by an abnormal and heterogeneous vascular network. These pathophysiological characteristics contribute to the enhanced permeability and retention (EPR) effect, which is one of the key rationales for developing tumor-targeted drug delivery systems. Vessel abnormality and heterogeneity, however, which typically result from excessive pro-angiogenic signaling, can also hinder efficient drug delivery to and into tumors. Using histidine-rich glycoprotein (HRG) knockout and wild type mice, and HRG-overexpressing and normal t241 fibrosarcoma cells, we evaluated the effect of genetically induced and macrophage-mediated vascular normalization on the tumor accumulation and penetration of 10-20 nm-sized polymeric drug carriers based on poly(N-(2-hydroxypropyl)methacrylamide). Multimodal and multiscale optical imaging was employed to show that normalizing the tumor vasculature improves the accumulation of fluorophore-labeled polymers in tumors, and promotes their penetration out of tumor blood vessels deep into the interstitium.

• Klíčová slova
• Drug delivery, EPR, HRG, Nanomedicine, Tumor targeting, Vascular normalization, pHPMA,
• MeSH
• kyseliny polymethakrylové metabolismus   farmakokinetika   MeSH
• myši inbrední C57BL MeSH
• myši knockoutované MeSH
• myši MeSH
• nádorové buněčné linie MeSH
• nádory krevní zásobení   genetika   metabolismus   MeSH
• nosiče léků metabolismus   farmakokinetika   MeSH
• permeabilita MeSH
• proteiny genetika   metabolismus   MeSH
• systémy cílené aplikace léků metody   MeSH
• tkáňová distribuce MeSH
• upregulace MeSH
• zvířata MeSH
• Check Tag
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• Duxon MeSH Prohlížeč
• histidine-rich proteins MeSH Prohlížeč
• kyseliny polymethakrylové MeSH
• nosiče léků MeSH
• proteiny MeSH

In our study, EPR spin-trapping technique was employed to study dark production of two reactive oxygen species, hydroxyl radicals (OH.) and singlet oxygen ((1)O2), in spinach photosystem II (PSII) membrane particles exposed to elevated temperature (47 degrees C). Production of OH., evaluated as EMPO-OH adduct EPR signal, was suppressed by the enzymatic removal of hydrogen peroxide and by the addition of iron chelator desferal, whereas externally added hydrogen peroxide enhanced OH. production. These observations reveal that OH. is presumably produced by metal-mediated reduction of hydrogen peroxide in a Fenton-type reaction. Increase in pH above physiological values significantly stimulated the formation of OH., whereas the presence of chloride and calcium ions had the opposite effect. Based on our results it is proposed that the formation of OH. is linked to the thermal disassembly of water-splitting manganese complex on PSII donor side. Singlet oxygen production, followed as the formation of nitroxyl radical TEMPO, was not affected by OH. scavengers. This finding indicates that the production of these two species was independent and that the production of (1)O2 is not closely linked to PSII donor side.

• MeSH
• elektronová paramagnetická rezonance metody   MeSH
• fotosystém II - proteinový komplex chemie   metabolismus   MeSH
• intracelulární membrány metabolismus   MeSH
• reaktivní formy kyslíku metabolismus   MeSH
• spin trapping metody   MeSH
• teplota * MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• fotosystém II - proteinový komplex MeSH
• reaktivní formy kyslíku MeSH

Enhanced permeability and retention (EPR) effect-based nanomedicine is a promising strategy for successful anticancer therapy. The EPR effect is based on tumor blood flow. Because advanced large tumors, as frequently seen in clinical settings, are heterogeneous, with regions of defective vasculature and blood flow, achieving the desired tumor drug delivery is difficult. Here, we utilized the EPR effect to increase drug delivery. To augment the EPR effect for improved therapeutic effects of nanomedicine, we exploited vascular mediators-the nitric oxide (NO) generators nitroglycerin (NG), hydroxyurea, and l-arginine. These compounds generate NO in tumors with relatively high selectivity. Using different nanosized drugs in our protocol significantly increased (1.5-2 times) delivery of nanomedicines to different solid tumor models, along with markedly improving (2-3-fold) the antitumor effects of these drugs. Also, in 7,12-dimethylbenz[a]anthracene-induced advanced end-stage breast cancer, often seen in clinical settings, 2 mg/kg polymer-conjugated pirarubicin (P-THP) with NG (0.2 mg/mouse) showed better effects than did 5 mg/kg P-THP, and 5 mg/kg P-THP used with NG resulted in cures or stable tumors (no tumor growth) for up to 120 days. Moreover, in a murine autochthonous azoxymethane/dextran sulfate sodium-induced colon cancer model, NO donors markedly improved the therapeutic effects of P-THP even after just one injection, results that were comparable with those achieved with three weekly P-THP treatments. These findings strongly suggest the potential usefulness of NO donors as EPR effect enhancers to improve the therapeutic efficacy of nanomedicines.

• MeSH
• antitumorózní látky farmakologie   MeSH
• arginin farmakologie   MeSH
• donory oxidu dusnatého farmakologie   MeSH
• doxorubicin analogy a deriváty   farmakologie   MeSH
• hydroxymočovina farmakologie   MeSH
• makromolekulární látky farmakologie   MeSH
• modely nemocí na zvířatech MeSH
• myši MeSH
• nádory krevní zásobení   patologie   MeSH
• nanočástice chemie   MeSH
• nanomedicína * MeSH
• nitroglycerin farmakologie   MeSH
• oxid dusnatý biosyntéza   MeSH
• permeabilita MeSH
• potkani Sprague-Dawley MeSH
• zvířata MeSH
• Check Tag
• mužské pohlaví MeSH
• myši MeSH
• ženské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• antitumorózní látky MeSH
• arginin MeSH
• donory oxidu dusnatého MeSH
• doxorubicin MeSH
• hydroxymočovina MeSH
• makromolekulární látky MeSH
• nitroglycerin MeSH
• oxid dusnatý MeSH
• pirarubicin MeSH Prohlížeč

Quinolinate (pyridine-2,3-dicarboxylic acid, Quin) is a neurotoxic tryptophan metabolite produced mainly by immune-activated macrophages. It is implicated in the pathogenesis of several brain disorders including HIV-associated dementia. Previous evidence suggests that Quin may exert its neurotoxic effects not only as an agonist on the NMDA subtype of glutamate receptor, but also by a receptor-independent mechanism. In this study we address ability of ferrous quinolinate chelates to generate reactive oxygen species. Autoxidation of Quin-Fe(II) complexes, followed in Hepes buffer at pH 7.4 using ferrozine as the Fe(II) detector, was found to be markedly slower in comparison with iron unchelated or complexed to citrate or ADP. The rate of Quin-Fe(II) autoxidation depends on pH (squared hydroxide anion concentration), is catalyzed by inorganic phosphate, and in both Hepes and phosphate buffers inversely depends on Quin concentration. These observations can be explained in terms of anion catalysis of hexaaquairon(II) autoxidation, acting mainly on the unchelated or partially chelated pool of iron. In order to follow hydroxyl radical generation in the Fenton chemistry, electron paramagnetic resonance (EPR) spin trapping with 5,5-dimethyl-1-pyrroline-N-oxide (DMPO) was employed. In the mixture consisting of 100 mM DMPO, 0.1 mM Fe(II), and 8.8 mM hydrogen peroxide in phosphate buffer pH 7.4, 0.5 mM Quin approximately doubled the yield of DMPO-OH adduct, and higher Quin concentration increased the spin adduct signal even more. When DMPO-OH was pre-formed using Ti3+ /hydrogen peroxide followed by peroxide removal with catalase, only addition of Quin-Fe(II), but not Fe(II), Fe(III), or Quin-Fe(III), significantly promoted decomposition of pre-formed DMPO-OH. Furthermore, reaction of Quin-Fe(II) with hydrogen peroxide leads to initial iron oxidation followed by appearance of iron redox cycling, detected as slow accumulation of ferrous ferrozine complex. This phenomenon cannot be abolished by subsequent addition of catalase. Thus, we propose that redox cycling of iron by a Quin derivative, formed by initial attack of hydroxyl radicals on Quin, rather than effects of iron complexes on DMPO-OH stability or redox cycling by hydrogen peroxide, is responsible for enhanced DMPO-OH signal in the presence of Quin. The present observations suggest that Quin-Fe(II) complexes display significant pro-oxidant characteristics that could have implications for Quin neurotoxicity.

• MeSH
• elektronová paramagnetická rezonance MeSH
• hydroxylový radikál chemie   metabolismus   MeSH
• kyselina chinolinová chemie   metabolismus   MeSH
• oxidace-redukce MeSH
• peroxid vodíku chemie   MeSH
• železo chemie   metabolismus   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• hydroxylový radikál MeSH
• kyselina chinolinová MeSH
• peroxid vodíku MeSH
• železo MeSH

Polymer carriers based on N-(2-hydroxypropyl)methacrylamide (HPMA) copolymers with incorporated organic nitrates as nitric oxide (NO) donors were designed with the aim to localise NO generation in solid tumours, thus highly increasing the enhanced permeability and retention (EPR) effect. The NO donors were coupled to the polymer carrier either through a stable bond or through a hydrolytically degradable, pH sensitive, bond. In vivo, the co-administration of the polymer NO donor and HPMA copolymer-bound cytotoxic drug (doxorubicin; Dox) resulted in an improvement in the treatment of murine EL4 T-cell lymphoma. The polymer NO donors neither potentiated the in vitro toxicity of the cytotoxic drug nor exerted any effect on in vivo model without the EPR effect, such as BCL1 leukaemia. Thus, an increase in passive accumulation of the nanomedicine carrying cytotoxic drug via NO-enhanced EPR effect was the operative mechanism of action. The most significant improvement in the therapy was observed in a combination treatment with such a polymer conjugate of Dox, which is characterised by increased circulation in the blood and efficient accumulation in solid tumours. Notably, the combination treatment enabled the development of an anti-tumour immune response, which was previously demonstrated as an important feature of HPMA-based polymer cytotoxic drugs.

• Klíčová slova
• Drug delivery, EL4 lymphoma, HPMA copolymers, anti-tumour immune response, enhanced EPR effect, polymer NO donor, polymer cytotoxic drugs, solid tumour treatment,
• MeSH
• antitumorózní látky aplikace a dávkování   metabolismus   MeSH
• donory oxidu dusnatého aplikace a dávkování   metabolismus   MeSH
• experimentální nádory farmakoterapie   metabolismus   patologie   MeSH
• myši inbrední BALB C MeSH
• myši inbrední C57BL MeSH
• myši MeSH
• nádorové buněčné linie MeSH
• nanočástice aplikace a dávkování   metabolismus   MeSH
• nosiče léků aplikace a dávkování   metabolismus   MeSH
• oxid dusnatý metabolismus   MeSH
• polymery aplikace a dávkování   metabolismus   MeSH
• tumor burden účinky léků   fyziologie   MeSH
• výsledek terapie MeSH
• zvířata MeSH
• Check Tag
• myši MeSH
• ženské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• antitumorózní látky MeSH
• donory oxidu dusnatého MeSH
• nosiče léků MeSH
• oxid dusnatý MeSH
• polymery MeSH

Recently, numerous polymer materials have been employed as drug carrier systems in medicinal research, and their detailed properties have been thoroughly evaluated. Water-soluble polymer carriers play a significant role between these studied polymer systems as they are advantageously applied as carriers of low-molecular-weight drugs and compounds, e.g., cytostatic agents, anti-inflammatory drugs, antimicrobial molecules, or multidrug resistance inhibitors. Covalent attachment of carried molecules using a biodegradable spacer is strongly preferred, as such design ensures the controlled release of the drug in the place of a desired pharmacological effect in a reasonable time-dependent manner. Importantly, the synthetic polymer biomaterials based on N-(2-hydroxypropyl) methacrylamide (HPMA) copolymers are recognized drug carriers with unique properties that nominate them among the most serious nanomedicines candidates for human clinical trials. This review focuses on advances in the development of HPMA copolymer-based nanomedicines within the passive and active targeting into the place of desired pharmacological effect, tumors, inflammation or bacterial infection sites. Specifically, this review highlights the safety issues of HPMA polymer-based drug carriers concerning the structure of nanomedicines. The main impact consists of the improvement of targeting ability, especially concerning the enhanced and permeability retention (EPR) effect.

• Klíčová slova
• EPR effect, HPMA copolymers, controlled release, drug delivery, nanomedicines,
• Publikační typ
• časopisecké články MeSH
• přehledy MeSH

Tumor-targeted photodynamic therapy (PDT) using polymeric photosensitizers is a promising therapeutic strategy for cancer treatment. In this study, we synthesized a pHPMA conjugated pyropheophorbide-a (P-PyF) as a cancer theranostic agent for PDT and photodynamic diagnostics (PDD). Pyropheophorbide-a has one carboxyl group which was conjugated to pHPMA via amide bond yielding the intended product with high purity. In aqueous solutions, P-PyF showed a mean particle size of ∼200 nm as it forms micelle which exhibited fluorescence quenching and thus very little singlet oxygen (1O2) production. In contrast, upon disruption of micelle strong fluorescence and 1O2 production were observed. In vitro study clearly showed the PDT effect of P-PyF. More potent 1O2 production and PDT effect were observed during irradiation at ∼420 nm, the maximal absorbance of pyropheophorbide-a, than irradiation at longer wavelength (i.e., ∼680 nm), suggesting selection of proper absorption light is essential for successful PDT. In vivo study showed high tumor accumulation of P-PyF compared with most of normal tissues due to the enhanced permeability and retention (EPR) effect, which resulting in superior antitumor effect under irradiation using normal xenon light source of endoscope, and clear tumor imaging profiles even in the metastatic lung cancer at 28 days after administration of P-PyF. On the contrary irradiation using long wavelength (i.e., ∼680 nm), the lowest Q-Band, exhibited remarkable tumor imaging effect with little autofluorescence of background. These findings strongly suggested P-PyF may be a potential candidate-drug for PDT/PDD, particularly using two different wavelength for treatment and detection/imaging, respectively.

• Klíčová slova
• EPR effect, Macromolecular photosensitizers, Polymeric micelles, Pyropheoporbide-a, Singlet oxygen, Tumor targeting,
• MeSH
• časové faktory MeSH
• chlorofyl aplikace a dávkování   analogy a deriváty   farmakokinetika   MeSH
• fluorescence MeSH
• fotochemoterapie metody   MeSH
• fotosenzibilizující látky aplikace a dávkování   MeSH
• kyseliny polymethakrylové chemie   MeSH
• micely MeSH
• myši inbrední BALB C MeSH
• myši inbrední C57BL MeSH
• myši MeSH
• nádory plic diagnóza   farmakoterapie   MeSH
• permeabilita MeSH
• polymery chemie   MeSH
• teranostická nanomedicína metody   MeSH
• tkáňová distribuce MeSH
• velikost částic MeSH
• zvířata MeSH
• Check Tag
• mužské pohlaví MeSH
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• chlorofyl MeSH
• Duxon MeSH Prohlížeč
• fotosenzibilizující látky MeSH
• kyseliny polymethakrylové MeSH
• micely MeSH
• polymery MeSH
• pyropheophorbide a MeSH Prohlížeč

In this study, we compared the enhanced permeability and retention (EPR) effect, toxicity, and therapeutic effect of the conjugate of the linear polymer poly(N-(2-hydroxypropyl)methacrylamide) (HPMA) with pirarubicin with an Mw below the renal threshold (39g/mol) (named LINEAR) and the disulfide-linked tandem-polymeric dimer of the poly(HPMA)-pirarubicin conjugate with an Mw above the renal threshold (93g/mol) (named DIBLOCK). The DIBLOCK conjugate, which was susceptible to reductive degradation, showed both a better EPR effect (tumor delivery) (2.5 times greater at 24h) and a prolonged plasma half-life. In addition, DIBLOCK had a better antitumor effect, as judged by percent survival, than did LINEAR (80% vs 65% at 150days), without any apparent toxicity in an S180 tumor model. However, the LD50 value of LINEAR was slightly higher than that of DIBLOCK (50mg/kg vs 37.5mg/kg, respectively). DIBLOCK required a longer time than LINEAR to reach maximum accumulation in the tumor. DIBLOCK also showed a greater time-dependent increase in the concentration in the tumor compared with the plasma concentration.

• Klíčová slova
• EPR effect, PHPMA conjugate, Pirarubicin, Tandem-diblock PHPMA conjugate, Tumor drug targeting,
• MeSH
• antitumorózní látky škodlivé účinky   chemie   farmakologie   MeSH
• biologická dostupnost MeSH
• biologický transport MeSH
• doxorubicin škodlivé účinky   analogy a deriváty   chemie   farmakologie   MeSH
• kyseliny polymethakrylové chemická syntéza   MeSH
• lidé MeSH
• molekulová hmotnost MeSH
• myši MeSH
• nádorové buněčné linie MeSH
• nosiče léků chemická syntéza   MeSH
• poločas MeSH
• renální reabsorpce MeSH
• tkáňová distribuce MeSH
• uvolňování léčiv MeSH
• vysokoúčinná kapalinová chromatografie metody   MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• mužské pohlaví MeSH
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• srovnávací studie MeSH
• Názvy látek
• antitumorózní látky MeSH
• doxorubicin MeSH
• Duxon MeSH Prohlížeč
• kyseliny polymethakrylové MeSH
• nosiče léků MeSH
• pirarubicin MeSH Prohlížeč