Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 50
Filtrar
1.
Cancers (Basel) ; 16(8)2024 Apr 11.
Artigo em Inglês | MEDLINE | ID: mdl-38672540

RESUMO

AIM: The complex medical care of synchronous metastatic colorectal (smCRC) patients requires prudent multidisciplinary planning and treatments due to various challenges caused by the primary tumor and its metastases. The role of primary tumor resection (PTR) is currently uncertain; strong arguments exist for and against it. We aimed to define its effect and find its best place in our therapeutic methodology. METHOD: We performed retrospective data analysis to investigate the clinical course of 449 smCRC patients, considering treatment modalities and the location of the primary tumor and comparing the clinical results of the patients with or without PTR between 1 January 2013 and 31 December 2018 at the Institute of Oncotherapy of the University of Pécs. RESULTS: A total of 63.5% of the 449 smCRC patients had PTR. Comparing their data to those whose primary tumor remained intact (IPT), we observed significant differences in median progression-free survival with first-line chemotherapy (mPFS1) (301 vs. 259 days; p < 0.0001; 1 y PFS 39.2% vs. 26.6%; OR 0.56 (95% CI 0.36-0.87)) and median overall survival (mOS) (760 vs. 495 days; p < 0.0001; 2 y OS 52.4 vs. 26.9%; OR 0.33 (95% CI 0.33-0.53)), respectively. However, in the PTR group, the average ECOG performance status was significantly better (0.98 vs. 1.1; p = 0.0456), and the use of molecularly targeted agents (MTA) (45.3 vs. 28.7%; p = 0.0005) and rate of metastasis ablation (MA) (21.8 vs. 1.2%; p < 0.0001) were also higher, which might explain the difference partially. Excluding the patients receiving MTA and MA from the comparison, the effect of PTR remained evident, as the mOS differences in the reduced PTR subgroup compared to the reduced IPT subgroup were still strongly significant (675 vs. 459 days; p = 0.0009; 2 y OS 45.9 vs. 24.1%; OR 0.37 (95% CI 0.18-0.79). Further subgroup analysis revealed that the site of the primary tumor also had a major impact on the outcome considering only the IPT patients; shorter mOS was observed in the extrapelvic IPT subgroup in contrast with the intrapelvic IPT group (422 vs. 584 days; p = 0.0026; 2 y OS 18.2 vs. 35.9%; OR 0.39 (95% CI 0.18-0.89)). Finally, as a remarkable finding, it should be emphasized that there were no differences in OS between the smCRC PTR subgroup and metachronous mCRC patients (mOS 760 vs. 710 days, p = 0.7504, 2 y OS OR 0.85 (95% CI 0.58-1.26)). CONCLUSIONS: The role of PTR in smCRC is still not professionally justified. Our survey found that most patients had benefited from PTR. Nevertheless, further prospective trials are needed to clarify the optimal treatment sequence of smCRC patients and understand this cancer disease's inherent biology.

2.
Sci Rep ; 14(1): 4286, 2024 02 21.
Artigo em Inglês | MEDLINE | ID: mdl-38383592

RESUMO

Cigarette smoking is a major preventable cause of morbidity and mortality. While quitting smoking is the best option, switching from cigarettes to non-combustible alternatives (NCAs) such as e-vapor products is a viable harm reduction approach for smokers who would otherwise continue to smoke. A key challenge for the clinical assessment of NCAs is that self-reported product use can be unreliable, compromising the proper evaluation of their risk reduction potential. In this cross-sectional study of 205 healthy volunteers, we combined comprehensive exposure characterization with in-depth multi-omics profiling to compare effects across four study groups: cigarette smokers (CS), e-vapor users (EV), former smokers (FS), and never smokers (NS). Multi-omics analyses included metabolomics, transcriptomics, DNA methylomics, proteomics, and lipidomics. Comparison of the molecular effects between CS and NS recapitulated several previous observations, such as increased inflammatory markers in CS. Generally, FS and EV demonstrated intermediate molecular effects between the NS and CS groups. Stratification of the FS and EV by combustion exposure markers suggested that this position on the spectrum between CS and NS was partially driven by non-compliance/dual use. Overall, this study highlights the importance of in-depth exposure characterization before biological effect characterization for any NCA assessment study.


Assuntos
Sistemas Eletrônicos de Liberação de Nicotina , Expossoma , Abandono do Hábito de Fumar , Produtos do Tabaco , Vaping , Humanos , Estudos Transversais , Multiômica
3.
Cancers (Basel) ; 15(21)2023 Oct 26.
Artigo em Inglês | MEDLINE | ID: mdl-37958320

RESUMO

AIM: The oncologic treatment of elderly patients is going on with a lack of evidence due to their underrepresentation in clinical trials. Many data suggest that certain groups of elderly patients, like their younger counterparts, may benefit from the systemic treatment of their metastatic colorectal tumors (mCRC). METHOD: We performed retrospective data analysis to investigate the clinical course of care and clinical outcomes of 515 patients who received first-line mFOLFIRI-based chemotherapy for mCRC between 1 January 2013 and 31 December 2018 at the Institute of Oncotherapy of the University of Pécs, focusing on a comparison of patients over and under 70 years of age, defined as the cut-off value. RESULTS: 28.7% of the 515 patients were 70 years old and older (median age 73.5 years). Compared to the data of the elderly patients, the younger group (median age 61.1 years) had a performance status that was significantly better (average ECOG 1.07 vs. 0.83, p < 0.0001), and significantly more patients received molecularly targeted agents (MTA) (21.6% vs. 51.8%, p < 0.0001); nevertheless, mPFS (241 vs. 285 days, p = 0.3960) and mOS (610 vs. 698 days, p = 0.6305) results did not differ significantly. Considering the 1y PFS OR and the 2ys OS OR values (0.94 [95%CI 0.63-1.41] and 0.72 [95%CI 0.47-1.09], respectively), only a non-significant trend was observed in OS favouring the younger population. Additional analysis of our data proved that the survival in patients over 70 years was positively affected by the addition of MTAs to the doublet chemotherapies, and the reasonable modifications/reductions in dose intensity and the addition of local interventions had similar positive effects as observed in the younger patients' group. CONCLUSIONS: Age stratification of mCRC patients is not professionally justified. Patients over 70 years of age with good performance status and controlled co-morbidities benefit from systemic therapy, its modifications and local treatment to the same extent as younger patients. With the increasing incidence of age-related cancers due to the rising average lifespan, prospective randomised clinical trials are needed to determine the real value of systemic therapy in the elderly and the rational, objective methods of patient selection.

4.
J Biotechnol ; 377: 43-52, 2023 Nov 20.
Artigo em Inglês | MEDLINE | ID: mdl-37890533

RESUMO

In this study we assessed the applicability of the recently reported ancestral l-amino acid oxidase (AncLAAO), for the development of an enzyme-coupled phenylalanine ammonia-lyase (PAL) activity assay. Firstly, the expression and isolation of the AncLAAO-N1 was optimized, followed by activity tests of the obtained octameric N-terminal His-tagged enzyme towards various phenylalanine analogues to assess the compatibility of its substrate scope with that of the well-characterized PALs. AncLAAO-N1 showed high catalytic efficiency towards phenylalanines mono-, di-, or multiple-substituted in the meta- or para-positions, with ortho- substituted substrates being poorly transformed, these results highlighting the significant overlap between its substrate scope and those of PALs. After successful set-up of the AncLAAO-PAL coupled solid phase assay, in a 'proof of concept' approach we demonstrated its applicability for the high-throughput activity screens of PAL-libraries, by screening the saturation mutagenesis-derived I460NNK variant library of PAL from Petroselinum crispum, using p-MeO-phenylalanine as model substrate. Notably, the hits revealed by the coupled assay comprised all the active PAL variants: I460V, I460T, I460S, I460L, previously identified from the tested PAL-library by other assays. Our results validate the applicability of AncLAAO for coupled enzyme systems with phenylalanine ammonia-lyases, including cell-based assays suitable for the high-throughput screening of directed evolution-derived PAL-libraries.


Assuntos
L-Aminoácido Oxidase , Fenilalanina Amônia-Liase , Fenilalanina Amônia-Liase/química , Fenilalanina/metabolismo , Catálise
5.
BMC Genomics ; 24(1): 516, 2023 Sep 04.
Artigo em Inglês | MEDLINE | ID: mdl-37667170

RESUMO

BACKGROUND: Anatabine, although being one of four major tobacco alkaloids, is never accumulated in high quantity in any of the naturally occurring species from the Nicotiana genus. Previous studies therefore focused on transgenic approaches to synthetize anatabine, most notably by generating transgenic lines with suppressed putrescine methyltransferase (PMT) activity. This led to promising results, but the global gene expression of plants with such distinct metabolism has not been analyzed. In the current study, we describe how these plants respond to topping and the downstream effects on alkaloid biosynthesis. RESULTS: The surge in anatabine accumulation in PMT transgenic lines after topping treatment and its effects on gene expression changes were analyzed. The results revealed increases in expression of isoflavone reductase-like (A622) and berberine bridge-like enzymes (BBLs) oxidoreductase genes, previously shown to be crucial for the final steps of nicotine biosynthesis. We also observed significantly higher methylputrescine oxidase (MPO) expression in all plants subjected to topping treatment. In order to investigate if MPO suppression would have the same effects as that of PMT, we generated transgenic plants. These plants with suppressed MPO expression showed an almost complete drop in leaf nicotine content, whereas leaf anatabine was observed to increase by a factor of ~ 1.6X. CONCLUSION: Our results are the first concrete evidence that suppression of MPO leads to decreased nicotine in favor of anatabine in tobacco roots and that this anatabine is successfully transported to tobacco leaves. Alkaloid transport in plants remains to be investigated to higher detail due to high variation of its efficiency among Nicotiana species and varieties of tobacco. Our research adds important step to better understand pyrrolidine ring biosynthesis and its effects on gene expression and subsequent accumulation of anatabine.


Assuntos
Alcaloides , Nicotiana , Nicotiana/genética , Nicotina , Folhas de Planta/genética , Pirrolidinas , Expressão Gênica
6.
Front Psychol ; 14: 1122339, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-36935987

RESUMO

Introduction: Fear of cancer progression (FoP) is one of the most frequently reported unmet needs invoked by the majority of cancer patients, which may significantly impair the quality of life (QoL) of patients. The major objective of the present cross-sectional study was to investigate the specificities of the relationship between different dimensions and intensity of FoP and different aspects of patients' QoL during the COVID-19 pandemic in Romania. Methods: A nationwide sample of 330 participants completed a survey, including measures of demographic characteristics, medical variables, QoL, and FoP. Multivariate General Linear and Hierarchical Regression Models were conducted in order to assess the relationship between variables. Result: Our results indicate that less than a quarter of the sample experienced low, between 63 and 70% moderate, and 15% high levels of FoP. Our results also indicate that anxiety/worry related to the possibility of progression of the disease, and loss of independence produced significant differences with large effect sizes in all the dimensions of QoL. Discussion: Our results indicate that besides affective reactions, the fear of cancer survivors to lose independence, not being able to attend to their own lives, seems to be a considerable threat, especially in the context of Romanian health system which has difficulties in offering qualitative psychosocial care for cancer patients. The idea that patients will have to rely on others and may not function well independently, not being able to attend to their own lives, seems to be a considerable threat, next to the experienced affective reactions per se.

7.
Appl Microbiol Biotechnol ; 107(4): 1243-1256, 2023 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-36662259

RESUMO

In this study, rational design and saturation mutagenesis efforts for engineering phenylalanine ammonia-lyase from Petroselinum crispum (PcPAL) provided tailored PALs active towards challenging, highly valuable di-substituted substrates, such as the L-DOPA precursor 3,4-dimethoxy-L-phenylalanine or the 3-bromo-4-methoxy-phenylalanine. The rational design approach and saturation mutagenesis strategy unveiled identical PcPAL variants of improved activity, highlighting the limited mutational variety of the substrate specificity-modulator residues, L134, F137, I460 of PcPAL. Due to the restricted catalytic efficiency of the best performing L134A/I460V and F137V/I460V PcPAL variants, we imprinted these beneficial mutations to PALs of different origins. The variants of PALs from Arabidopsis thaliana (AtPAL) and Anabaena variabilis (AvPAL) showed higher catalytic efficiency than their PcPAL homologues. Further, the engineered PALs were also compared in terms of catalytic efficiency with a novel aromatic ammonia-lyase from Loktanella atrilutea (LaAAL), close relative of the metagenome-derived aromatic ammonia-lyase AL-11, reported recently to possess atypically high activity towards substrates with electron-donor aromatic substituents. Indeed, LaAAL outperformed the engineered Pc/At/AvPALs in the production of 3,4-dimethoxy-L-phenylalanine; however, in case of 3-bromo-4-methoxy derivatives it showed no activity, with computational results supporting the occurrence of steric hindrance. Transferring the unique array of selectivity modulator residues from LaAAL to the well-characterized PALs did not enhance their activity towards the targeted substrates. Moreover, applying the rational design strategy valid for these well-characterized PALs to LaAAL decreased its activity. These results suggest that distinct tailoring rationale is required for LaAAL/AL-11-like aromatic ammonia-lyases, which might represent a distinct PAL subclass, with natural reaction and substrate scope modified through evolutionary processes. KEY POINTS: • PAL-activity for challenging substrates generated by protein engineering • Rational/semi-rational protein engineering reveals constrained mutational variability • Engineered PALs are outperformed by novel ALs of distinct catalytic site signature.


Assuntos
Fenilalanina Amônia-Liase , Engenharia de Proteínas , Fenilalanina Amônia-Liase/genética , Fenilalanina Amônia-Liase/metabolismo , Domínio Catalítico , Fenilalanina , Mutação
8.
J Org Chem ; 88(2): 852-862, 2023 01 20.
Artigo em Inglês | MEDLINE | ID: mdl-36583610

RESUMO

An efficient preparative-scale synthetic procedure of l-phenylalanine derivatives has been developed using mutant variants of phenylalanine ammonia-lyase from Arabidopsis thaliana (AtPAL). After rigorous reaction engineering, the AtPAL-catalyzed hydroamination reaction of cinnamic acids provided several unnatural amino acids of high synthetic value, such as (S)-m- and (S)-p-methoxyphenylalanine; (S)-o- and (S)-m-methylphenylalanine; and (S)-o- and (S)-p-bromophenylalanine at preparative scale, significantly surpassing the catalytic efficiency in terms of conversions and yields of the previously reported PcPAL-based biotransformations. The AtPAL variants tolerated high substrate and product concentrations, representing an important extension of the PAL-toolbox, while the engineered biocatalytic procedures of improved E-factor and space-time yields fulfill the requirements of sustainable and green chemistry, providing facile access to valuable amino acid building blocks.


Assuntos
Arabidopsis , Fenilalanina Amônia-Liase , Fenilalanina Amônia-Liase/genética , Fenilalanina Amônia-Liase/química , Fenilalanina Amônia-Liase/metabolismo , Fenilalanina , Aminoácidos , Biocatálise
9.
Molecules ; 27(22)2022 Nov 21.
Artigo em Inglês | MEDLINE | ID: mdl-36432206

RESUMO

There is an increasingly urgent call to shift industrial processes from fossil fuel feedstock to sustainable bio-based resources. This change becomes of high importance considering new budget requirements for a carbon-neutral economy. Such a transformation can be driven by traditionally used plants that are able to produce large amounts of valuable biologically relevant secondary metabolites. Tobacco plants can play a leading role in providing value-added products in remote areas of the world. In this study, we propose a non-exhaustive list of compounds with potential economic interest that can be sourced from the tobacco plant. In order to optimize extraction methodologies, we first analyzed their physico-chemical properties using rapid solubility tests and high-resolution microfractionation techniques. Next, to identify an optimal extraction for a selected list of compounds, we compared 13 different extraction method-solvent combinations. We proceeded with profiling some of these compounds in a total of six varieties from Nicotiana tabacum and Nicotiana rustica species, identifying the optimal variety for each. The estimated expected yields for each of these compounds demonstrate that tobacco plants can be a superior source of valuable compounds with diverse applications beyond nicotine. Among the most interesting results, we found high variability of anatabine content between species and varieties, ranging from 287 to 1699 µg/g. In addition, we found that CGA (1305 µg/g) and rutin (7910 µg/g) content are orders of magnitude lower in the Burley variety as compared to all others.


Assuntos
Fracionamento Químico , Nicotiana , Nicotiana/química , Nicotina/metabolismo
10.
Orv Hetil ; 163(43): 1704-1712, 2022 Oct 23.
Artigo em Húngaro | MEDLINE | ID: mdl-36273353

RESUMO

An increasing proportion of cancer patients remains permanently tumorfree after primary care due to modern curative treatments. However, the life expectancy and quality of life deteriorate significantly in most relapsed cases in spite of different palliative therapies. To detect the early relapse in asymptomatic stage, patients undergo a preplanned care process, targeting primarily their improved survival. Several studies and reviews have been conducted in recent decades to determine the optimal and rational frequency and methods of control examinations. The data of different followup strategies were analyzed from several perspectives. Recommended followup protocols differ significantly based on the origin, histological characteristics, stage, prognostic factors and typical sites of recurrences, such as local, "oligometastatic" or systemic relapse of tumors. In addition to the detection of recurrence, the importance of qual ity of life, monitoring of psychological status and psychosomatic complaints as well as the costeffectiveness of protocols also came to the focus. Involving family doctors or qualified nurses in routine oncology followup may function as an alternative option to reducing the workload of specialists. The COVID­19 pandemic resulted in the use of telemedicine methods in the evaluation of examinations and followup strategies coming to the fore, while at the same time this made the reevaluation of control care algorithms even more important. In this paper, we review the results of studies comparing the different followup strategies, highlighting which protocols help to optimize the use of health care capacity while preserving the survival chance of cancer patients in relapse.


Assuntos
COVID-19 , Qualidade de Vida , Humanos , Recidiva Local de Neoplasia , Pandemias , COVID-19/epidemiologia , Análise Custo-Benefício
11.
J Am Soc Mass Spectrom ; 33(11): 2147-2155, 2022 Nov 02.
Artigo em Inglês | MEDLINE | ID: mdl-36218284

RESUMO

Inhalation as a route for administering drugs and dietary supplements has garnered significant attention over the past decade. We performed real-time analyses of aerosols using secondary electrospray ionization (SESI) technology interfaced with high-resolution mass spectrometry (HRMS), primarily developed for exhaled breath analysis with the goal to detect the main aerosol constituents. Several commercially available inhalation devices containing caffeine, melatonin, cannabidiol, and vitamin B12 were tested. Chemical characterization of the aerosols produced by these devices enabled detection of the main constituents and screening for potential contaminants, byproducts, and impurities in the aerosol. In addition, a programmable syringe pump was connected to the SESI-HRMS system to monitor aerosolized active pharmaceutical ingredients (APIs) such as chloroquine, hydroxychloroquine, and azithromycin. This setup allowed us to detect caffeine, melatonin, hydroxychloroquine, chloroquine, and cannabidiol in the produced aerosols. Azithromycin and vitamin B12 in the aerosols could not be detected; however, our instrument setup enabled the detection of vitamin B12 breakdown products that were generated during the aerosolization process. Positive control was realized by liquid chromatography-HRMS analyses. The compounds detected in the aerosol were confirmed by exact mass measurements of the protonated and/or deprotonated species, as well as their respective collision-induced dissociation tandem mass spectra. These results reveal the potential wide application of this technology for the real-time monitoring of aerosolized active pharmaceutical ingredients that can be administered through the inhalation route.


Assuntos
Canabidiol , Melatonina , Espectrometria de Massas por Ionização por Electrospray/métodos , Cafeína , Azitromicina , Hidroxicloroquina , Aerossóis/análise , Vitamina B 12
12.
Nat Commun ; 13(1): 3127, 2022 06 06.
Artigo em Inglês | MEDLINE | ID: mdl-35668111

RESUMO

Estrogen and progesterone receptor (ER, PR) signaling control breast development and impinge on breast carcinogenesis. ER is an established driver of ER + disease but the role of the PR, itself an ER target gene, is debated. We assess the issue in clinically relevant settings by a genetic approach and inject ER + breast cancer cell lines and patient-derived tumor cells to the milk ducts of immunocompromised mice. Such ER + xenografts were exposed to physiologically relevant levels of 17-ß-estradiol (E2) and progesterone (P4). We find that independently both premenopausal E2 and P4 levels increase tumor growth and combined treatment enhances metastatic spread. The proliferative responses are patient-specific with MYC and androgen receptor (AR) signatures determining P4 response. PR is required for tumor growth in patient samples and sufficient to drive tumor growth and metastasis in ER signaling ablated tumor cells. Our findings suggest that endocrine therapy may need to be personalized, and that abrogating PR expression can be a therapeutic option.


Assuntos
Neoplasias da Mama , Receptores de Progesterona , Animais , Neoplasias da Mama/metabolismo , Estradiol/farmacologia , Estradiol/uso terapêutico , Feminino , Humanos , Camundongos , Progesterona/farmacologia , Receptores de Estrogênio/genética , Receptores de Estrogênio/metabolismo , Receptores de Progesterona/genética , Receptores de Progesterona/metabolismo
13.
Sci Rep ; 12(1): 10606, 2022 06 23.
Artigo em Inglês | MEDLINE | ID: mdl-35739148

RESUMO

Unnatural substituted amino acids play an important role as chiral building blocks, especially for pharmaceutical industry, where the synthesis of chiral biologically active molecules still represents an open challenge. Recently, modification of the hydrophobic binding pocket of phenylalanine ammonia-lyase from Petroselinum crispum (PcPAL) resulted in specifically tailored PcPAL variants, contributing to a rational design template for PAL-activity enhancements towards the differently substituted substrate analogues. Within this study we tested the general applicability of this rational design model in case of PALs, of different sources, such as from Arabidopsis thaliana (AtPAL) and Rhodosporidium toruloides (RtPAL). With some exceptions, the results support that the positions of substrate specificity modulating residues are conserved among PALs, thus the mutation with beneficial effect for PAL-activity enhancement can be predicted using the established rational design model. Accordingly, the study supports that tailoring PALs of different origins and different substrate scope, can be performed through a general method. Moreover, the fact that AtPAL variants I461V, L133A and L257V, all outperformed in terms of catalytic efficiency the corresponding, previously reported, highly efficient PcPAL variants, of identical catalytic site, suggests that not only catalytic site differences influence the PAL-activity, thus for the selection of the optimal PAL-biocatalysts for a targeted process, screening of PALs from different origins, should be included.


Assuntos
Petroselinum , Fenilalanina Amônia-Liase , Sítios de Ligação , Domínio Catalítico , Petroselinum/genética , Fenilalanina Amônia-Liase/metabolismo , Especificidade por Substrato
14.
Sci Rep ; 12(1): 3347, 2022 03 01.
Artigo em Inglês | MEDLINE | ID: mdl-35232989

RESUMO

The interest towards ferulic acid decarboxylase (FDC), piqued by the enzyme's unique 1,3-dipolar cycloaddition mechanism and its atypic prFMN cofactor, provided several applications of the FDC mediated decarboxylations, such as the synthesis of styrenes, or its diverse derivatives, including 1,3-butadiene and the enzymatic activation of C-H bonds through the reverse carboligation reactions. While rational design-based protein engineering was successfully employed for tailoring FDC towards diverse substrates of interest, the lack of high-throughput FDC-activity assay hinders its directed evolution-based protein engineering. Herein we report a toolbox, useful for the directed evolution based and/or structure-guided protein engineering of FDC, which was validated representatively on the well described FDC, originary from Saccharomyces cerevisiae (ScFDC). Accordingly, the developed fluorescent plate-assay allows in premiere the FDC-activity screens of a mutant library in a high-throughput manner. Moreover, using the plate-assay for the activity screens of a rationally designed 23-membered ScFDC variant library against a substrate panel comprising of 16, diversely substituted cinnamic acids, revealed several variants of improved activity. The superior catalytic properties of the hits revealed by the plate-assay, were also supported by the conversion values from their analytical scale biotransformations. The computational results further endorsed the experimental findings, showing inactive binding poses of several non-transformed substrate analogues within the active site of the wild-type ScFDC, but favorable ones within the catalytic site of the variants of improved activity. The results highlight several 'hot-spot' residues involved in substrate specificity modulation of FDC, such as I189, I330, F397, I398 or Q192, of which mutations to sterically less demanding residues increased the volume of the active site, thus facilitated proper binding and increased conversions of diverse non-natural substrates. Upon revealing which mutations improve the FDC activity towards specific substrate analogues, we also provide key for the rational substrate-tailoring of FDC.


Assuntos
Carboxiliases , Carboxiliases/metabolismo , Catálise , Domínio Catalítico , Saccharomyces cerevisiae/genética , Saccharomyces cerevisiae/metabolismo , Especificidade por Substrato
15.
Catal Sci Technol ; 11(16): 5553-5563, 2021 Aug 16.
Artigo em Inglês | MEDLINE | ID: mdl-34745555

RESUMO

Phenylalanine ammonia-lyases (PALs) catalyse the non-oxidative deamination of l-phenylalanine to trans-cinnamic acid, while in the presence of high ammonia concentration, the synthetically attractive reverse reaction occurs. Although they have been intensively studied, the wider application of PALs for the large scale synthesis of non-natural amino acids is still rather limited, mainly due to the decreased operational stability of PALs under the high ammonia concentration conditions of ammonia addition. Herein, we describe the development of a highly stable and active immobilized PAL-biocatalyst obtained through site-specific covalent immobilization onto single-walled carbon nanotubes (SWCNTs), employing maleimide/thiol coupling of engineered enzymes containing surficial Cys residues. The immobilization method afforded robust biocatalysts (by strong covalent attachment to the support) and allowed modulation of enzymatic activity (by proper selection of binding site, controlling the orientation of the enzyme attached to the support). The novel biocatalysts were investigated in PAL-catalyzed reactions, focusing on the synthetically challenging ammonia addition reaction. The optimization of the immobilization (enzyme load) and reaction conditions (substrate : biocatalyst ratio, ammonia source, reaction temperature) involving the best performing biocatalyst SWCNTNH2 -SS-PcPAL was performed. The biocatalyst, under the optimal reaction conditions, showed high catalytic efficiency, providing excellent conversion (c ∼90% in 10 h) of cinnamic acid into l-Phe, and more importantly, possesses high operational stability, maintaining its high efficiency over >7 reaction cycles. Moreover, the site-specifically immobilized PcPAL L134A/S614C and PcPAL I460V/S614C variants were successfully applied in the synthesis of several l-phenylalanine analogues of high synthetic value, providing perspectives for the efficient replacement of classical synthetic methods for l-phenylalanines with a mild, selective and eco-friendly enzymatic alternative.

16.
Inter Econ ; 56(5): 284-287, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34629506

RESUMO

Climate crisis is becoming higher on the agenda of the decision makers of the world. A huge amount of resources have been dedicated to green projects, however far less emphasis has been put on tax policy opportunities. Carbon pricing can increase the burden of CO2 producers, but this does not appear to be enough. We need a Green Tax Reform which focuses on the Pigouvian approach and can correct the distortions of different climate hurting activities. Through tax policy tools, the price structure should be drastically changed and serious incentives should be provided to change the behaviours of the consumers and producers to achieve green policy goals.

17.
Pathol Oncol Res ; 27: 608446, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34257570

RESUMO

Purpose: The aim of this study was to introduce the simultaneous integrated boost (SIB) technique to assess the safety of replacement of the brachytherapy (BT) boost for ineligible patients with cervical cancer receiving radiochemotherapy (RCT). Methods: Fourteen patients were enrolled between 2015 and 2018. SIB was delivered using RapidArc technique at doses of 2.4 Gy per fraction during pelvic irradiation with 50.4/1.8 Gy in seven patients (to a total dose of 67.2 Gy) with limited volume disease. In 7 patients with a more advanced disease stage (>5 cm tumor, parametric invasion both sides), parametric boost therapy was added to the pelvic radiotherapy to a total dose of the macroscopic tumor of 79.2 Gy. All patients received simultaneous cisplatin-based chemotherapy for 5 cycles with a dosage of 40 mg/m2. We examined acute toxicity (CTCAE v4.1) and quality of life (EORTC QLQ30 and CX24). The tumor regression rate was evaluated with RECIST 1.1 after the first 3- to 4-months follow-up Magnetic Resonance Imaging (MRI) scan. We calculated the percentage of tumor regression rate and the local control during the follow-up period and evaluated the survival data. Results: Our patient data are presented at a median follow-up time of 24.5 months. During the treatment period, no grade 3 to 4 toxicity was observed. During the follow-up period, no late-onset toxicity was observed. The tumor regression rate at the first MRI scan was 95.31% on average. Disease free survival (DFS) during the median follow-up of 24 months was 98.6%. Conclusion: In patients with cervical cancer, the SIB technique is amenable as part of definitive RCT. Dose escalation with the SIB technique can be safely administered to cervical cancer patients during definitive RCT if BT is not feasible. However, further randomized clinical studies are needed to validate the method, so routine use of it cannot be recommended yet.


Assuntos
Radioterapia Guiada por Imagem/métodos , Radioterapia de Intensidade Modulada/métodos , Neoplasias do Colo do Útero/radioterapia , Adulto , Idoso , Idoso de 80 Anos ou mais , Quimiorradioterapia/métodos , Feminino , Humanos , Pessoa de Meia-Idade , Projetos Piloto , Estudos Prospectivos , Dosagem Radioterapêutica , Planejamento da Radioterapia Assistida por Computador/métodos
18.
EMBO Mol Med ; 13(7): e14314, 2021 07 07.
Artigo em Inglês | MEDLINE | ID: mdl-34042278

RESUMO

Hormonal contraception exposes women to synthetic progesterone receptor (PR) agonists, progestins, and transiently increases breast cancer risk. How progesterone and progestins affect the breast epithelium is poorly understood because we lack adequate models to study this. We hypothesized that individual progestins differentially affect breast epithelial cell proliferation and hence breast cancer risk. Using mouse mammary tissue ex vivo, we show that testosterone-related progestins induce the PR target and mediator of PR signaling-induced cell proliferation receptor activator of NF-κB ligand (Rankl), whereas progestins with anti-androgenic properties in reporter assays do not. We develop intraductal xenografts of human breast epithelial cells from 36 women, show they remain hormone-responsive and that progesterone and the androgenic progestins, desogestrel, gestodene, and levonorgestrel, promote proliferation but the anti-androgenic, chlormadinone, and cyproterone acetate, do not. Prolonged exposure to androgenic progestins elicits hyperproliferation with cytologic changes. Androgen receptor inhibition interferes with PR agonist- and levonorgestrel-induced RANKL expression and reduces levonorgestrel-driven cell proliferation. Thus, different progestins have distinct biological activities in the breast epithelium to be considered for more informed choices in hormonal contraception.


Assuntos
Androgênios , Progestinas , Animais , Proliferação de Células , Anticoncepcionais , Camundongos
19.
Biomolecules ; 10(6)2020 05 30.
Artigo em Inglês | MEDLINE | ID: mdl-32486192

RESUMO

Phenylalanine ammonia-lyases (PALs) are attractive biocatalysts for the stereoselective synthesis of non-natural phenylalanines. The rational design of PALs with extended substrate scope, highlighted the substrate specificity-modulator role of residue I460 of Petroselinum crispum PAL. Herein, saturation mutagenesis at key residue I460 was performed in order to identify PcPAL variants of enhanced activity or to validate the superior catalytic properties of the rationally explored I460V PcPAL compared with the other possible mutant variants. After optimizations, the saturation mutagenesis employing the NNK-degeneracy generated a high-quality transformant library. For high-throughput enzyme-activity screens of the mutant library, a PAL-activity assay was developed, allowing the identification of hits showing activity in the reaction of non-natural substrate, p-MeO-phenylalanine. Among the hits, besides the known I460V PcPAL, several mutants were identified, and their increased catalytic efficiency was confirmed by biotransformations using whole-cells or purified PAL-biocatalysts. Variants I460T and I460S were superior to I460V-PcPAL in terms of catalytic efficiency within the reaction of p-MeO-Phe. Moreover, I460T PcPAL maintained the high specificity constant of the wild-type enzyme for the natural substrate, l-Phe. Molecular docking supported the favorable substrate orientation of p-MeO-cinnamic acid within the active site of I460T variant, similarly as shown earlier for I460V PcPAL (PDB ID: 6RGS).


Assuntos
Petroselinum/enzimologia , Fenilalanina Amônia-Liase/genética , Biocatálise , Simulação de Acoplamento Molecular , Mutação , Fenilalanina Amônia-Liase/química , Fenilalanina Amônia-Liase/metabolismo
20.
Nat Commun ; 11(1): 1571, 2020 03 26.
Artigo em Inglês | MEDLINE | ID: mdl-32218432

RESUMO

Estrogens and progesterone control breast development and carcinogenesis via their cognate receptors expressed in a subset of luminal cells in the mammary epithelium. How they control the extracellular matrix, important to breast physiology and tumorigenesis, remains unclear. Here we report that both hormones induce the secreted protease Adamts18 in myoepithelial cells by controlling Wnt4 expression with consequent paracrine canonical Wnt signaling activation. Adamts18 is required for stem cell activation, has multiple binding partners in the basement membrane and interacts genetically with the basal membrane-specific proteoglycan, Col18a1, pointing to the basement membrane as part of the stem cell niche. In vitro, ADAMTS18 cleaves fibronectin; in vivo, Adamts18 deletion causes increased collagen deposition during puberty, which results in impaired Hippo signaling and reduced Fgfr2 expression both of which control stem cell function. Thus, Adamts18 links luminal hormone receptor signaling to basement membrane remodeling and stem cell activation.


Assuntos
Proteínas ADAMTS/metabolismo , Hormônios/farmacologia , Glândulas Mamárias Animais/citologia , Nicho de Células-Tronco , Células-Tronco/metabolismo , Proteínas ADAMTS/deficiência , Proteínas ADAMTS/genética , Animais , Antígenos CD/metabolismo , Linhagem Celular , Autorrenovação Celular/efeitos dos fármacos , Epitélio/metabolismo , Matriz Extracelular/efeitos dos fármacos , Matriz Extracelular/metabolismo , Feminino , Fibronectinas/metabolismo , Glicoproteínas/metabolismo , Humanos , Camundongos Endogâmicos C57BL , Modelos Biológicos , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Receptores de Progesterona/metabolismo , Regeneração/efeitos dos fármacos , Transdução de Sinais/efeitos dos fármacos , Nicho de Células-Tronco/efeitos dos fármacos , Células-Tronco/citologia , Células-Tronco/efeitos dos fármacos , Transcrição Gênica/efeitos dos fármacos
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA