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1.
Ann Neurol ; 91(1): 23-32, 2022 01.
Artigo em Inglês | MEDLINE | ID: mdl-34786756

RESUMO

OBJECTIVE: Perfusion imaging identifies anterior circulation stroke patients who respond favorably to endovascular thrombectomy (ET), but its role in basilar artery occlusion (BAO) is unknown. We hypothesized that BAO patients with limited regions of severe hypoperfusion (time to reach maximum concentration in seconds [Tmax] > 10) would have a favorable response to ET compared to patients with more extensive regions involved. METHODS: We performed a multicenter retrospective cohort study of BAO patients with perfusion imaging prior to ET. We prespecified a Critical Area Perfusion Score (CAPS; 0-6 points), which quantified severe hypoperfusion (Tmax > 10) in cerebellum (1 point/hemisphere), pons (2 points), and midbrain and/or thalamus (2 points). Patients were dichotomized into favorable (CAPS ≤ 3) and unfavorable (CAPS > 3) groups. The primary outcome was a favorable functional outcome 90 days after ET (modified Rankin Scale = 0-3). RESULTS: One hundred three patients were included. CAPS ≤ 3 patients (87%) had a lower median National Institutes of Health Stroke Scale score (NIHSS; 12.5, interquartile range [IQR] = 7-22) compared to CAPS > 3 patients (13%; 23, IQR = 19-36; p = 0.01). Reperfusion was achieved in 84% of all patients, with no difference between CAPS groups (p = 0.42). Sixty-four percent of reperfused CAPS ≤ 3 patients had a favorable outcome compared to 8% of nonreperfused CAPS ≤ 3 patients (odds ratio [OR] = 21.0, 95% confidence interval [CI] = 2.6-170; p < 0.001). No CAPS > 3 patients had a favorable outcome, regardless of reperfusion. In a multivariate regression analysis, CAPS ≤ 3 was a robust independent predictor of favorable outcome after adjustment for reperfusion, age, and pre-ET NIHSS (OR = 39.25, 95% CI = 1.34->999, p = 0.04). INTERPRETATION: BAO patients with limited regions of severe hypoperfusion had a favorable response to reperfusion following ET. However, patients with more extensive regions of hypoperfusion in critical brain regions did not benefit from endovascular reperfusion. ANN NEUROL 2022;91:23-32.


Assuntos
Imagem de Perfusão/métodos , Trombectomia , Resultado do Tratamento , Insuficiência Vertebrobasilar/diagnóstico por imagem , Insuficiência Vertebrobasilar/cirurgia , Adulto , Idoso , Estudos de Coortes , Procedimentos Endovasculares/métodos , Feminino , Humanos , Imageamento por Ressonância Magnética/métodos , Masculino , Pessoa de Meia-Idade , Neuroimagem/métodos , Reperfusão/métodos , Estudos Retrospectivos , Tomografia Computadorizada por Raios X/métodos , Insuficiência Vertebrobasilar/patologia
2.
Angew Chem Int Ed Engl ; 62(10): e202217233, 2023 03 01.
Artigo em Inglês | MEDLINE | ID: mdl-36628505

RESUMO

AuI -carbene and PtIV -AuI -carbene prodrugs display low to sub-µM activity against several cancer cell lines and overcome cisplatin (cisPt) resistance. Linking a cisPt-derived PtIV (phenylbutyrate) complex to a AuI -phenylimidazolylidene complex 2, yielded the most potent prodrug. While in vivo tests against Lewis Lung Carcinoma showed that the prodrug PtIV (phenylbutyrate)-AuI -carbene (7) and the 1 : 1 : 1 co-administration of cisPt: phenylbutyrate:2 efficiently inhibited tumor growth (≈95 %), much better than 2 (75 %) or cisPt (84 %), 7 exhibited only 5 % body weight loss compared to 14 % for 2, 20 % for cisPt and >30 % for the co-administration. 7 was much more efficient than 2 at inhibiting TrxR activity in the isolated enzyme, in cells and in the tumor, even though it was much less efficient than 2 at binding to selenocysteine peptides modeling the active site of TrxR. Organ distribution and laser-ablation (LA)-ICP-TOFMS imaging suggest that 7 arrives intact at the tumor and is activated there.


Assuntos
Antineoplásicos , Pró-Fármacos , Antineoplásicos/química , Fenilbutiratos , Pró-Fármacos/química , Linhagem Celular Tumoral , Cisplatino/química
3.
Angew Chem Int Ed Engl ; 62(42): e202310774, 2023 10 16.
Artigo em Inglês | MEDLINE | ID: mdl-37646232

RESUMO

A multitargeting prodrug (2) that releases gemcitabine, oxaliplatin, and doxorubicin in their active form in cancer cells is a potent cytotoxic agent with nM IC50s ; it is highly selective to cancer cells with mean selectivity indices to human (136) and murine (320) cancer cells. It effectively induces release of DAMPs (CALR, ATP & HMGB1) in CT26 cells facilitating more efficient phagocytosis by J774 macrophages than the FDA drugs or their co-administration. The viability of CT26 cells co-cultured with J774 macrophages and treated with 2 was reduced by 32 % compared to the non-treated cells, suggesting a synergistic antiproliferative effect between the chemical and immune reactions. 2 inhibited in vivo tumor growth in two murine models (LLC and CT26) better than the FDA drugs or their co-administration with significantly lower body weight loss. Mice inoculated with CT26 cells treated with 2 showed slightly better tumor free survival than doxorubicin.


Assuntos
Antineoplásicos , Neoplasias , Pró-Fármacos , Camundongos , Humanos , Animais , Oxaliplatina/farmacologia , Gencitabina , Pró-Fármacos/farmacologia , Pró-Fármacos/uso terapêutico , Morte Celular Imunogênica , Antineoplásicos/farmacologia , Antineoplásicos/uso terapêutico , Doxorrubicina/farmacologia , Doxorrubicina/uso terapêutico , Linhagem Celular Tumoral
4.
J Anim Ecol ; 91(8): 1612-1626, 2022 08.
Artigo em Inglês | MEDLINE | ID: mdl-35603988

RESUMO

The management of sustainable harvest of animal populations is of great ecological and conservation importance. Development of formal quantitative tools to estimate and mitigate the impacts of harvest on animal populations has positively impacted conservation efforts. The vast majority of existing harvest models, however, do not simultaneously estimate ecological and harvest impacts on demographic parameters and population trends. Given that the impacts of ecological drivers are often equal to or greater than the effects of harvest, and can covary with harvest, this disconnect has the potential to lead to flawed inference. In this study, we used Bayesian hierarchical models and a 43-year capture-mark-recovery dataset from 404,241 female mallards Anas platyrhynchos released in the North American midcontinent to estimate mallard demographic parameters. Furthermore, we model the dynamics of waterfowl hunters and habitat, and the direct and indirect effects of anthropogenic and ecological processes on mallard demographic parameters. We demonstrate that density dependence, habitat conditions and harvest can simultaneously impact demographic parameters of female mallards, and discuss implications for existing and future harvest management models. Our results demonstrate the importance of controlling for multicollinearity among demographic drivers in harvest management models, and provide evidence for multiple mechanisms that lead to partial compensation of mallard harvest. We provide a novel model structure to assess these relationships that may allow for improved inference and prediction in future iterations of harvest management models across taxa.


Assuntos
Efeitos Antropogênicos , Ecossistema , Animais , Teorema de Bayes , Patos , Feminino , Dinâmica Populacional
5.
Chem Biodivers ; 19(10): e202200695, 2022 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-36026613

RESUMO

α-Lipoic acid, known for its anti-inflammatory and antioxidant activity, represents a promising ligand for Pt(IV) prodrugs. Three new Pt(IV) lipoate complexes were synthesized and characterized by NMR spectroscopy (1 H, 13 C, 195 Pt), mass spectrometry and elemental analysis. Due to the low solubility of the complex containing two axial lipoate ligands, further experiments to examine the biological activity were performed with two Pt(IV) complexes containing just one axial lipoate ligand. Both complexes exhibit anticancer activity and produce reactive oxygen species (ROS) in the cell lines tested. Especially, the monosubstituted complex can be reduced by ascorbic acid and forms adducts with 9-methylguanine (9MeG), which is favorable for the formation of DNA-crosslinks in the cells.


Assuntos
Antineoplásicos , Pró-Fármacos , Ácido Tióctico , Antineoplásicos/química , Antioxidantes , Ácido Ascórbico , Linhagem Celular Tumoral , DNA , Ligantes , Estrutura Molecular , Pró-Fármacos/farmacologia , Pró-Fármacos/química , Espécies Reativas de Oxigênio/metabolismo
6.
Inorg Chem ; 59(7): 5182-5193, 2020 Apr 06.
Artigo em Inglês | MEDLINE | ID: mdl-32207294

RESUMO

Multiaction Pt(IV) prodrugs can overcome resistance associated with the FDA approved Pt(II) drugs like cisplatin. Intracellular reduction of the octahedral Pt(IV) derivatives of cisplatin releases cisplatin and the two axial ligands. When the released axial ligands act synergistically with cisplatin to kill the cancer cells, we have multiaction prodrugs. Most Pt(IV) multiaction prodrugs have bioactive ligands possessing a carboxylate that is conjugated to the Pt(IV) because breaking the Pt(IV)-ligand bond releases the active moiety. As many drugs that act synergistically with cisplatin do not have carboxylates, a major challenge is to prepare multiaction Pt(IV) complexes with drugs that have amino groups or hydroxyl groups such that following reduction, the drugs are released in their active form. Our objective was to prepare multiaction Pt(IV) prodrugs that release bioactive molecules having amino groups. Because we cannot conjugate amino groups to the axial position of Pt(IV), we developed a novel and efficient approach for the synthesis of Pt(IV)-carbamato complexes and demonstrated that following reduction of the Pt(IV), the released carbamates undergo rapid decarboxylation, releasing the free amine, as in the case of the PARP-1 inhibitor 3-aminobenzamide and the amino derivative of the HDAC inhibitor SAHA. Pt(IV)-carbamato complexes are stable in cell culture medium and are reduced by ascorbate. They are reduced slower than their carboxylato and carbonato analogues. We believe that this approach paves the way for preparing novel classes of multiaction Pt(IV) prodrugs with amino containing bioactive molecules that up to now were not accessible.


Assuntos
Antineoplásicos/farmacologia , Carbamatos/farmacologia , Complexos de Coordenação/farmacologia , Pró-Fármacos/farmacologia , Antineoplásicos/síntese química , Benzamidas/farmacologia , Carbamatos/síntese química , Linhagem Celular Tumoral , Cisplatino/farmacologia , Complexos de Coordenação/síntese química , Ensaios de Seleção de Medicamentos Antitumorais , Humanos , Ligantes , Oxirredução , Platina/química , Pró-Fármacos/síntese química
7.
Angew Chem Int Ed Engl ; 59(18): 7069-7075, 2020 04 27.
Artigo em Inglês | MEDLINE | ID: mdl-32017379

RESUMO

PtII complexes are commonly used to treat cancer. To reduce their side effects and improve their pharmacological properties, PtIV complexes are being developed as prodrug candidates that are activated by reduction in cancer cells. Concomitantly, RuII polypyridine complexes have gained much attention as photosensitizers for use in photodynamic therapy due to their attractive characteristics. In this article, a novel PtIV -RuII conjugate, which combines cancer activated chemotherapy with PDT, is presented. Upon entering the cancer cell, the PtIV centre is reduced to PtII and the axial ligands including the RuII complex and phenylbutyrate are released. As each component has its individual targets, the conjugate exerts a multi-target and multi-action effect with (photo-)cytotoxicity values upon irradiation up to 595 nm in the low nanomolar range in various (drug resistant) 2D monolayer cancer cells and 3D multicellular tumour spheroids.


Assuntos
Antineoplásicos/farmacologia , Complexos de Coordenação/farmacologia , Resistencia a Medicamentos Antineoplásicos/efeitos dos fármacos , Fotoquimioterapia , Fármacos Fotossensibilizantes/farmacologia , Platina/farmacologia , Rutênio/farmacologia , Antineoplásicos/síntese química , Antineoplásicos/química , Linhagem Celular , Proliferação de Células/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Complexos de Coordenação/síntese química , Complexos de Coordenação/química , Ensaios de Seleção de Medicamentos Antitumorais , Quimioterapia Combinada , Humanos , Raios Infravermelhos , Estrutura Molecular , Fármacos Fotossensibilizantes/síntese química , Fármacos Fotossensibilizantes/química , Platina/química , Rutênio/química
8.
Chemistry ; 25(20): 5235-5245, 2019 Apr 05.
Artigo em Inglês | MEDLINE | ID: mdl-30740808

RESUMO

Dual- or multi-action PtIV prodrugs represent a new generation of platinum anticancer drugs. The important property of these PtIV prodrugs is that their antitumor action combines several different mechanisms owing to the presence of biologically active axial ligands. This work describes the synthesis and some biological properties of a "triple-action" prodrug that releases in cancer cells cisplatin and two different epigenetically acting moieties, octanoate and phenylbutyrate. It is demonstrated, with the aid of modern methods of molecular and cellular biology and pharmacology, that the presence of three different functionalities in a single molecule of the PtIV prodrug results in a selective and high potency in tumor cells including those resistant to cisplatin [the IC50 values in the screened malignant cell lines ranged from as low as 9 nm (HCT-116) to 74 nm (MDA-MB-231)]. It is also demonstrated that cellular activation of the PtIV prodrug results in covalent modification of DNA through the release of the platinum moiety accompanied by inhibition of the activity of histone deacetylases caused by phenylbutyrate and by global hypermethylation of DNA by octanoate. Thus, the PtIV prodrug introduced in this study acts as a true "multi-action" prodrug, which is over two orders of magnitude more active than clinically used cisplatin, in both 2D monolayer culture and 3D spheroid cancer cells.


Assuntos
Antineoplásicos/química , Cisplatino/química , Dano ao DNA , Epigênese Genética , Pró-Fármacos/química , Antineoplásicos/farmacologia , Transporte Biológico , Caprilatos/química , Caprilatos/farmacologia , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Cisplatino/farmacologia , Metilação de DNA , Ensaios de Seleção de Medicamentos Antitumorais , Histona Desacetilases/metabolismo , Humanos , Fenilbutiratos/química , Fenilbutiratos/farmacologia , Pró-Fármacos/farmacologia
9.
Inorg Chem ; 58(24): 16676-16688, 2019 Dec 16.
Artigo em Inglês | MEDLINE | ID: mdl-31790216

RESUMO

Pt(II) complexes, such as cisplatin and oxaliplatin, are in widespread use as anticancer drugs. Their use is limited by the toxic side effects and the ability of tumors to develop resistance to the drugs. A popular approach to overcome these drawbacks is to use their kinetically inert octahedral Pt(IV) derivatives that act as prodrugs. The most successful Pt(IV) complex in clinical trials to date is satraplatin, cct-[Pt(NH3)(c-hexylamine)Cl2(OAc)2], that upon cellular reduction releases the cytotoxic cis-[Pt(NH3)(c-hexylamine)Cl2]. In an attempt to obtain water-soluble and more effective cytotoxic Pt(IV) complexes, we prepared a series of dual- and triple-action satraplatin analogues, where the equatorial chlorido ligands were replaced with acetates and the axial ligands include innocent and bioactive ligands. Replacement of the chlorides with acetates enhanced the water solubility of the compounds and, with one exception, all of the compounds were very stable in buffer. In general, compounds with one or two axial hydroxido ligands were reduced by ascorbate significantly more quickly than compounds with two axial carboxylates. While replacement of the chlorides with acetates in satraplatin led to a reduction in cytotoxicity, the dual- and triple-action analogues with equatorial acetates had low- to sub-micromolar IC50 values in a panel of eight cancer cells. The triple-action compound cct-[Pt(NH3)(c-hexylamine)(OAc)2(PhB)(DCA)] was active in all cell lines, causing DNA damage that induced cell cycle inhibition and apoptosis. Its good activity against CT26 cells in vitro translated into good in vivo efficacy against the CT26 allograft, an in vivo model with intrinsic satraplatin resistance. This indicates that multiaction Pt(IV) derivatives of diamine dicarboxylates are interesting anticancer drug candidates.

10.
Angew Chem Int Ed Engl ; 58(50): 18218-18223, 2019 12 09.
Artigo em Inglês | MEDLINE | ID: mdl-31599054

RESUMO

Most multi-action PtIV prodrugs have bioactive ligands containing carboxylates. This is probably due to the ease of carboxylating the OH axial ligands and because following reduction, the active drug is released. A major challenge is to expand the arsenal of bioactive ligands to include those without carboxylates. We describe a general approach for synthesis of PtIV prodrugs that release drugs with OH groups. We linked the OH groups of gemcitabine (Gem), paclitaxel (Tax), and estramustine (EM) to the PtIV derivative of cisplatin by a carbonate bridge. Following reduction, the axial ligands lost CO2 , rapidly generating the active drugs. In contrast, succinate-linked drugs did not readily release the free drugs. The carbonate-bridged ctc-[Pt(NH3 )2 (PhB)(Gem-Carb)Cl2 ] was significantly more cytotoxic than the succinate-bridged ctc-[Pt(NH3 )2 (PhB)(Gem-Suc)Cl2 ], and more potent and less toxic than gemcitabine, cisplatin, and co-administration of cisplatin and gemcitabine.


Assuntos
Antineoplásicos/química , Antineoplásicos/farmacologia , Compostos Organoplatínicos/química , Compostos Organoplatínicos/farmacologia , Animais , Antineoplásicos/síntese química , Protocolos de Quimioterapia Combinada Antineoplásica/farmacologia , Carbonatos/química , Carcinoma Pulmonar de Lewis/tratamento farmacológico , Linhagem Celular Tumoral , Cisplatino/administração & dosagem , Cisplatino/química , Desoxicitidina/administração & dosagem , Desoxicitidina/análogos & derivados , Desoxicitidina/química , Ensaios de Seleção de Medicamentos Antitumorais , Estramustina/química , Feminino , Humanos , Ligantes , Masculino , Camundongos Endogâmicos C57BL , Compostos Organoplatínicos/síntese química , Paclitaxel/química , Pró-Fármacos , Proibitinas , Relação Estrutura-Atividade , Gencitabina
11.
Angew Chem Int Ed Engl ; 58(24): 8109-8114, 2019 06 11.
Artigo em Inglês | MEDLINE | ID: mdl-30945417

RESUMO

A novel and highly efficient dual-targeting platform was designed to ensure targeted in vivo delivery of dual-action PtIV prodrugs. The dual targeting was established by liposomal encapsulation of PtIV complexes, thereby utilizing the enhanced permeability and retention (EPR) effect as the first stage of targeting to attain a high accumulation of the drug-loaded liposomes in the tumor. After the release of the PtIV prodrug inside cancer cells, a second stage of targeting directed a portion of the PtIV prodrugs to the mitochondria. Upon intracellular reduction, these PtIV prodrugs released two bioactive molecules, acting both on the mitochondrial and on the nuclear DNA. Our PtIV system showed excellent activity in vitro and in vivo, characterized by a cytotoxicity in a low micromolar range and complete tumor remission, respectively. Notably, marked in vivo activity was accompanied by reduced kidney toxicity, highlighting the unique therapeutic potential of our novel dual-targeting dual-action platform.


Assuntos
Antineoplásicos/uso terapêutico , Rim/efeitos dos fármacos , Platina/uso terapêutico , Antineoplásicos/farmacologia , Humanos , Platina/farmacologia
12.
Angew Chem Int Ed Engl ; 56(38): 11539-11544, 2017 09 11.
Artigo em Inglês | MEDLINE | ID: mdl-28759160

RESUMO

We developed a novel PtIV prodrug that simultaneously releases four different bioactive moieties inside the cancer cell. Its cytotoxicity against monolayer cultures (2D) and spheroid (3D) cancer cells is significantly better than cisplatin. It is 200-450-fold more potent than cisplatin against KRAS mutated pancreatic and colon cancers and is 40-fold more selective towards KRAS mutated cells compared to non-cancerous. This is important since RAS proteins play a role in regulating cell differentiation, proliferation, and survival and KRAS is mutated in 90 % of pancreatic adenocarcinomas, 45 % of colorectal cancers, and 35 % of lung adenocarcinomas. The selectivity index, determined by dividing the IC50 value in non-cancerous cells by that of a cancerous cell line, is two-fold better than cisplatin, attesting to preferential cytotoxicity towards neoplastic cells.


Assuntos
Antineoplásicos/farmacologia , Compostos Organoplatínicos/farmacologia , Pró-Fármacos/farmacologia , Proteínas Proto-Oncogênicas p21(ras)/antagonistas & inibidores , Antineoplásicos/química , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Relação Dose-Resposta a Droga , Ensaios de Seleção de Medicamentos Antitumorais , Humanos , Compostos Organoplatínicos/química , Pró-Fármacos/química , Proteínas Proto-Oncogênicas p21(ras)/genética , Proteínas Proto-Oncogênicas p21(ras)/metabolismo , Relação Estrutura-Atividade
13.
BMC Genomics ; 16: 1100, 2015 Dec 23.
Artigo em Inglês | MEDLINE | ID: mdl-26699284

RESUMO

BACKGROUND: Understanding the mechanisms by which neurons are generated and specified, and how they integrate into functional circuits is key to being able to treat disorders of the nervous system and acute brain trauma. Much of what we know about neuronal differentiation has been studied in developing embryos, but differentiation steps may be very different during adult neurogenesis. For this reason, we compared the transcriptomes of newly differentiated neurons in zebrafish embryos and adults. RESULTS: Using a 4tU RNA labeling method, we isolated and sequenced mRNA specifically from cells of one day old embryos and adults expressing the transgene HA-uprt-mcherry under control of the neuronal marker elavl3. By categorizing transcript products into different protein classes, we identified similarities and differences of gene usage between adult and embryonic neuronal differentiation. We found that neurons in the adult brain and in the nervous system of one day old embryos commonly use transcription factors - some of them identical - during the differentiation process. When we directly compared adult differentiating neurons to embryonic differentiating neurons, however, we found that during adult neuronal differentiation, the expression of neuropeptides and neurotransmitter pathway genes is more common, whereas classical developmental signaling through secreted molecules like Hedgehog or Wnt are less enriched, as compared to embryonic stages. CONCLUSIONS: We conclude that both adult and embryonic differentiating neurons show enriched use of transcription factors compared to surrounding cells. However, adult and embryonic developing neurons use alternative pathways to differentiate. Our study provides evidence that adult neuronal differentiation is distinct from the better characterized embryonic neuronal differentiation process. This important insight and the lists of enriched genes we have identified will now help pave the way to a better understanding of the mechanisms of embryonic and adult neuronal differentiation and how to manipulate these processes.


Assuntos
Perfilação da Expressão Gênica/métodos , Neurogênese , Neurônios/citologia , Peixe-Zebra/embriologia , Peixe-Zebra/genética , Animais , Diferenciação Celular , Regulação da Expressão Gênica , Neuropeptídeos/genética , Análise de Sequência de RNA/métodos , Transdução de Sinais , Fatores de Transcrição/genética
14.
Development ; 139(9): 1691-9, 2012 May.
Artigo em Inglês | MEDLINE | ID: mdl-22492359

RESUMO

To understand the molecular mechanisms of development it is essential to be able to turn genes on and off at will and in a spatially restricted fashion. Morpholino oligonucleotides (MOs) are very common tools used in several model organisms with which it is possible to block gene expression. Recently developed photo-activated MOs allow control over the onset of MO activity. However, deactivation of photo-cleavable MO activity has remained elusive. Here, we describe photo-cleavable MOs with which it is possible to activate or de-activate MO function by UV exposure in a temporal and spatial manner. We show, using several different genes as examples, that it is possible to turn gene expression on or off both in the entire zebrafish embryo and in single cells. We use these tools to demonstrate the sufficiency of no tail expression as late as tailbud stage to drive medial precursor cells towards the notochord cell fate. As a broader approach for the use of photo-cleavable MOs, we show temporal control over gal4 function, which has many potential applications in multiple transgenic lines. We demonstrate temporal manipulation of Gal4 transgene expression in only primary motoneurons and not secondary motoneurons, heretofore impossible with conventional transgenic approaches. In another example, we follow and analyze neural crest cells that regained sox10 function after deactivation of a photo-cleavable sox10-MO at different time points. Our results suggest that sox10 function might not be critical during neural crest formation.


Assuntos
Regulação da Expressão Gênica no Desenvolvimento/efeitos da radiação , Morfolinos/efeitos da radiação , Fatores de Transcrição SOXE/metabolismo , Raios Ultravioleta , Proteínas de Peixe-Zebra/metabolismo , Peixe-Zebra/embriologia , Peixe-Zebra/metabolismo , Animais , Diferenciação Celular/efeitos da radiação , Proteínas de Ligação a DNA/metabolismo , Proteínas Fetais , Regulação da Expressão Gênica no Desenvolvimento/genética , Imuno-Histoquímica , Morfolinos/genética , Morfolinos/metabolismo , Neurônios Motores/metabolismo , Crista Neural/citologia , Crista Neural/metabolismo , Notocorda/citologia , Notocorda/embriologia , Proteínas com Domínio T/metabolismo , Fatores de Transcrição/metabolismo , Peixe-Zebra/genética
15.
Opt Lett ; 40(21): 5074-7, 2015 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-26512522

RESUMO

We demonstrate a low-loss, repeatable, and robust splice between single-mode silica fiber and single-mode chalcogenide (CHG) fiber. These splices are particularly difficult to create because of the significant difference in the two fibers' glass transition temperatures (∼1000°C) as well as the large difference in the coefficients of thermal expansion between the fibers (∼20×10(-6)/°C). With 90% light coupled through the silica-CHG fiber splice, predominantly in the fundamental circular-symmetric mode, into the core of the CHG fiber and with 0.5 dB of splice loss measured around the wavelength of 2.5 µm, after correcting only for the Fresnel loss, the silica-CHG splice offers excellent beam quality and coupling efficiency. The tensile strength of the splice is greater than 12 kpsi, and the laser damage threshold is greater than 2 W (CW) and was limited by the available laser pump power. We also utilized this splicing technique to demonstrate 2 to 4.5 µm ultrabroadband supercontinuum generation in a monolithic all-fiber system comprising a CHG fiber and a high peak power 2 µm pulsed Raman-shifted thulium fiber laser. This is a major development toward compact form factor commercial applications of soft-glass mid-IR fibers.


Assuntos
Calcogênios/química , Tecnologia de Fibra Óptica/instrumentação , Vidro/química , Raios Infravermelhos , Lasers , Dióxido de Silício/química , Módulo de Elasticidade , Transferência de Energia , Desenho de Equipamento , Análise de Falha de Equipamento , Temperatura Alta , Luz , Teste de Materiais , Espalhamento de Radiação , Integração de Sistemas
16.
Chemistry ; 21(7): 3108-14, 2015 Feb 09.
Artigo em Inglês | MEDLINE | ID: mdl-25529335

RESUMO

The design of Pt(IV) pro-drugs as anticancer agents is predicated on the assumption that they will not undergo substitution reactions before entering the cancer cell. Attempts to improve the cytotoxic properties of Pt(IV) pro-drugs included the use of haloacetato axial ligands. Herein, we demonstrate that Pt(IV) complexes with trifluoroacetato (TFA) or dichloroacetato (DCA) ligands can be unstable under biologically relevant conditions and readily undergo hydrolysis, which results in the loss of the axial TFA or DCA ligands. The half-lives for Pt(IV) complexes with two TFA or DCA ligands at pH 7 and 37 °C range from 6 to 800 min, which is short relative to the duration of cytotoxicity experiments that last 24-96 h. However, complexes with two monochloroacetato (MCA) or acetato axial ligands are stable under biologically relevant conditions. The loss of the axial ligands depends primarily on the electron-withdrawing strength of the axial ligands, but also upon the nature of the equatorial ligands. We were unable to find obvious correlations between the structures of the Pt(IV) complexes and the rates of decay of the parent compounds. The X-ray crystal structures of the bis-DCA and bis-MCA Pt(IV) derivatives of oxaliplatin did not reveal any significant structural differences that could explain the observed differences in stability.


Assuntos
Platina/química , Pró-Fármacos/química , Humanos , Hidrólise , Ligantes , Espectroscopia de Ressonância Magnética , Estrutura Molecular , Estereoisomerismo
17.
Nanomedicine ; 10(7): 1465-75, 2014 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-24486857

RESUMO

Carbon nanotubes (CNTs) are promising drug delivery systems due to their external functionalizable surface and their hollowed cavity that can encapsulate several bioactive molecules. In this study, the chemotherapeutic drug cisplatin or an inert platinum(IV) complex were entrapped inside functionalized-multi-walled-CNTs and intravenously injected into mice to investigate the influence of CNTs on the biodistribution of Pt-based molecules. The platinum levels in vital organs suggested that functionalized-CNTs did not affect cisplatin distribution, while they significantly enhanced the accumulation of Pt(IV) sample in some tissues (e.g. in the lungs, suggesting their potential application in lung cancer therapy) and reduced both kidney and liver accumulation (thus decreasing eventual nephrotoxicity, a typical side effect of cisplatin). Concurrently, CNTs did not induce any intrinsic abnormal immune response or inflammation, as confirmed by normal cytokine levels and histological evaluations. Therefore, functionalized nanotubes represent an efficient nano-carrier to improve accumulation of Pt species in targeted tissues/organs. From the clinical editor: In this preclinical study functionalized carbon nanotubes are reported to be safe and efficient for targeted delivery of platinum-containing compounds in rodents. Approaches like this may improve the treatment of specific cancers, since platinum based chemotherapies are commonly used, yet limited by toxicity and relatively poor target tissue concentration.


Assuntos
Antineoplásicos/farmacocinética , Nanotubos de Carbono , Compostos de Platina/farmacocinética , Animais , Portadores de Fármacos , Feminino , Camundongos , Camundongos Endogâmicos BALB C , Distribuição Tecidual
18.
J Assist Reprod Genet ; 31(7): 889-97, 2014 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-24789167

RESUMO

PURPOSE: To identify an association between amino acids (AAs) metabolism and reproductive outcome. METHODS: Prospective collection, observational study, in patients undergoing fresh, double embryo transfer (ET), in a tertiary hospital referral IVF unit. Spent day 1 and day 3 media were collected. Concentrations of taurine, aspartic acid, proline, and serine in the medium were determined using a liquid-chromatography mass-spectrometer (LCMS/MS). Data was analyzed according to excretion versus uptake, and a cut-off value was calculated based on a receiver operating curve (ROC). Pregnancy rates were also calculated after stratification into subgroups in accordance with AA metabolism. RESULTS: Seven out of 19 patients conceived (36.8 %). The ORs for pregnancy when the zygotes secreted aspartic acid, serine and proline above the cut-off value were 2.9, 5.67 and 5.21 (p < 0.05). When both transferred embryos were above the cut-off value of serine the PR's were 62.5 %, 12.5 % when both were below, and 33.3 % when one was above and the other below (p = 0.04). Similar results were obtained for proline; PR's were 66.7, 18.7 and 28.6 % respectively, but with a borderline statistical significance (p = 0.08). The same trend was observed in the case of aspartic acid but not near statistical significance. No differences in PRs were found in association with taurine turnover during fertilization or any of the studied AAs during the cleavage stage. There was no correlation between zygote or embryo AAs metabolism and embryo morphology. CONCLUSIONS: Serine and possibly proline decreased uptake from the fertilization medium is associated with pregnancy and might be useful for embryo selection.


Assuntos
Meios de Cultura/química , Fertilização in vitro , Serina/metabolismo , Zigoto/efeitos dos fármacos , Adulto , Fase de Clivagem do Zigoto/metabolismo , Implantação do Embrião/efeitos dos fármacos , Transferência Embrionária , Feminino , Humanos , Gravidez , Prolina/metabolismo , Prolina/farmacologia , Serina/farmacologia , Zigoto/crescimento & desenvolvimento , Zigoto/metabolismo
19.
J Med Chem ; 67(11): 9745-9758, 2024 Jun 13.
Artigo em Inglês | MEDLINE | ID: mdl-38819023

RESUMO

Herein, we describe the general design, synthesis, characterization, and biological activity of new multitargeting Pt(IV) prodrugs that combine antitumor cisplatin and dasatinib, a potent inhibitor of Src kinase. These prodrugs exhibit impressive antiproliferative and anti-invasive activities in tumor cell lines in both two-dimensional (2D) monolayers of cell cultures and three-dimensional (3D) spheroids. We show that the cisplatin moiety and dasatinib in the investigated Pt(IV) complexes are both involved in the mechanism of action in MCF7 breast cancer cells and act synergistically. Thus, combining dasatinib and cisplatin into one molecule, compared to using individual components in a mix, may bring several advantages, such as significantly higher activity in cancer cell lines and higher selectivity for tumor cells. Most importantly, Pt(IV)-dasatinib complexes hold significant promise for potential anticancer therapies by targeting epithelial-mesenchymal transition, thus preventing the spread and metastasis of tumors, a value unachievable by a simple combination of both individual components.


Assuntos
Antineoplásicos , Cisplatino , Dasatinibe , Sinergismo Farmacológico , Pró-Fármacos , Dasatinibe/farmacologia , Dasatinibe/química , Dasatinibe/síntese química , Humanos , Pró-Fármacos/farmacologia , Pró-Fármacos/química , Pró-Fármacos/síntese química , Cisplatino/farmacologia , Antineoplásicos/farmacologia , Antineoplásicos/química , Antineoplásicos/síntese química , Proliferação de Células/efeitos dos fármacos , Linhagem Celular Tumoral , Células MCF-7 , Ensaios de Seleção de Medicamentos Antitumorais , Compostos Organoplatínicos/farmacologia , Compostos Organoplatínicos/química , Compostos Organoplatínicos/síntese química
20.
Inorg Chem Front ; 11(2): 534-548, 2024 Jan 16.
Artigo em Inglês | MEDLINE | ID: mdl-38235273

RESUMO

While platinum-based chemotherapeutic agents have established themselves as indispensable components of anticancer therapy, they are accompanied by a variety of side effects and the rapid occurrence of drug resistance. A promising strategy to address these challenges is the use of platinum(iv) prodrugs, which remain inert until they reach the tumor tissue, thereby mitigating detrimental effects on healthy cells. Typically, platinum drugs are part of combination therapy settings. Consequently, a very elegant strategy is the development of platinum(iv) prodrugs bearing a second, clinically relevant therapeutic in axial position. In the present study, we focused on gemcitabine as an approved antimetabolite, which is highly synergistic with platinum drugs. In addition, to increase plasma half-life and facilitate tumor-specific accumulation, an albumin-binding maleimide moiety was attached. Our investigations revealed that maleimide-cisplatin(iv)-gemcitabine complexes cannot carry sufficient amounts of gemcitabine to induce a significant effect in vivo. Consequently, we designed a carboplatin(iv) analog, that can be applied at much higher doses. Remarkably, this novel analog demonstrated impressive in vivo results, characterized by significant improvements in overall survival. Notably, these encouraging results could also be transferred to an in vivo xenograft model with acquired gemcitabine resistance, indicating the high potential of this approach.

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