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1.
Cancers (Basel) ; 16(9)2024 Apr 28.
Artigo em Inglês | MEDLINE | ID: mdl-38730672

RESUMO

The incidence of gastric cancer (GC) is expected to increase to 1.77 million cases by 2040. To improve treatment outcomes, GC patients are increasingly treated with neoadjuvant chemotherapy (NAC) prior to curative-intent resection. Although NAC enhances locoregional control and comprehensive patient care, survival rates remain poor, and further investigations should establish outcomes assessment of current clinical pathways. Individually assessed parameters have served as benchmarks for treatment quality in the past decades. The Outcome4Medicine Consensus Conference underscores the inadequacy of isolated metrics, leading to increased recognition and adoption of composite measures. One of the most simple and comprehensive is the "All or None" method, which refers to an approach where a specific set of criteria must be fulfilled for an individual to achieve the overall measure. This narrative review aims to present the rationale for the implementation of a novel composite measure, Textbook Neoadjuvant Outcome (TNO). TNO integrates five objective and well-established components: Treatment Toxicity, Laboratory Tests, Imaging, Time to Surgery, and Nutrition. It represents a desired, multidisciplinary care and hospitalization of GC patients undergoing NAC to identify the treatment- and patient-related data required to establish high-quality oncological care further. A key strength of this narrative review is the clinical feasibility and research background supporting the implementation of the first and novel composite measure representing the "ideal" and holistic care among patients with locally advanced esophago-gastric junction (EGJ) and GC in the preoperative period after NAC. Further analysis will correlate clinical outcomes with the prognostic factors evaluated within the TNO framework.

2.
Nat Struct Mol Biol ; 31(5): 752-756, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38467877

RESUMO

The 20S U5 small nuclear ribonucleoprotein particle (snRNP) is a 17-subunit RNA-protein complex and a precursor of the U4/U6.U5 tri-snRNP, the major building block of the precatalytic spliceosome. CD2BP2 is a hallmark protein of the 20S U5 snRNP, absent from the mature tri-snRNP. Here we report a high-resolution cryogenic electron microscopy structure of the 20S U5 snRNP, shedding light on the mutually exclusive interfaces utilized during tri-snRNP assembly and the role of the CD2BP2 in facilitating this process.


Assuntos
Microscopia Crioeletrônica , Modelos Moleculares , Ribonucleoproteína Nuclear Pequena U5 , Humanos , Ribonucleoproteína Nuclear Pequena U5/química , Ribonucleoproteína Nuclear Pequena U5/metabolismo , Spliceossomos/metabolismo , Spliceossomos/química , Spliceossomos/ultraestrutura , Conformação Proteica , Chaperonas Moleculares/metabolismo , Chaperonas Moleculares/química
3.
Cancers (Basel) ; 16(5)2024 Feb 21.
Artigo em Inglês | MEDLINE | ID: mdl-38473228

RESUMO

The 5th edition of the World Health Organization (WHO) classification of tumors of the digestive system distinguishes four categories of appendiceal tumors (ATs): serrated lesions and polyps, mucinous neoplasms, adenocarcinomas, and neuroendocrine neoplasms (NENs). The differential diagnosis of ATs can be challenging in medical practice, due to their rarity and lack of data from randomized controlled trials on a large, diverse group of patients. ATs are usually noted in specimens obtained during appendectomies due to clinical acute appendicitis. In the European population, most ATs (65%) occur over the age of 50 and among women (56.8%). According to histological type, 54.6% are neuroendocrine tumors (NETs); 26.8% cystic, mucinous, and serous neoplasms; and 18.6% adenocarcinoma not otherwise specified (NOS). On pathologic analysis, most AT findings are benign lesions or small NENs that do not require further therapeutic measures. The presence of appendiceal mucinous neoplasm (AMN) can lead to pseudomyxoma peritonei (PMP). While the multimodal treatment for abdominal malignancies has evolved over the past several decades, the clinical workup and treatment of ATs remain a challenge. Therefore, this review aims to describe the diagnostic possibilities, molecular-based diagnosis, staging, differences in the treatment process, and prognostic factors associated with ATs.

4.
PLoS One ; 19(2): e0297583, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38319910

RESUMO

European data suggests that over 30% of gastric cancer (GC) patients are diagnosed with sarcopenia before surgery, while unintentional weight loss occurs in approximately 30% of patients following gastrectomy. Preoperative sarcopenia significantly increases the risk of major postoperative complications, and preoperative body weight loss remains a superior predictor of outcome and an independent prognostic factor for overall survival (OS) in patients with GC. A standardized approach of nutritional risk screening of GC patients is yet to be established. Therefore, the MOONRISE study aims to prospectively analyze the changes in nutritional status and body composition at each stage of multimodal treatment among GC patients from five Western expert centers. Specifically, we seek to assess the association between nutritional status and body composition on tumor response following neoadjuvant chemotherapy (NAC). Secondary outcomes of the study are treatment toxicity, postoperative complications, quality of life (QoL), and OS. Patients with locally advanced gastric adenocarcinoma scheduled for multimodal treatment will be included in the study. Four consecutive nutritional status assessments will be performed throughout the treatment. The following study was registered in ClinicalTrials.gov (Identifier: NCT05723718) and will be conducted in accordance with the STROBE statement. The anticipated duration of the study is 12-24 months, depending on the recruitment status. Results of this study will reveal whether nutritional status and body composition assessment based on BIA will become a validated and objective tool to support clinical decisions in GC patients undergoing multimodal treatment.


Assuntos
Desnutrição , Sarcopenia , Neoplasias Gástricas , Humanos , Neoplasias Gástricas/patologia , Qualidade de Vida , Sarcopenia/etiologia , Estudos Longitudinais , Impedância Elétrica , Estudos Transversais , Desnutrição/diagnóstico , Estado Nutricional , Complicações Pós-Operatórias/etiologia , Gastrectomia/efeitos adversos , Estudos Multicêntricos como Assunto
5.
Cancers (Basel) ; 16(4)2024 Feb 18.
Artigo em Inglês | MEDLINE | ID: mdl-38398218

RESUMO

Since increasing evidence underlines the prominent role of systemic inflammation in carcinogenesis, the inflammation burden index (IBI) has emerged as a promising biomarker to estimate survival outcomes among cancer patients. The IBI has only been validated in Eastern gastric cancer (GC) patients; therefore, the aim of this study was to evaluate the IBI as a prognostic biomarker in Central European GC patients undergoing multimodal treatment. Ninety-three patients with histologically confirmed GC who underwent multimodal treatment between 2013 and 2021 were included. Patient recruitment started with the standardization of neoadjuvant chemotherapy (NAC). Blood samples were obtained one day prior to surgical treatment. The textbook outcome (TO) served as the measure of surgical quality, and tumor responses to NAC were evaluated according to Becker's system tumor regression grade (TRG). A high IBI was associated with an increased risk of postoperative complications (OR 2.95, 95% CI 1.13-7.72). In multivariate analysis, a high IBI (HR = 2.56, 95% CI 1.28-5.13) and a high neutrophil-to-lymphocyte ratio (NLR, HR = 2.55, 95% CI 1.32-4.94) were associated with an increased risk of death, while NAC administration (HR = 0.40, 95% CI 0.18-0.90) and TO achievement (HR = 0.42, 95% CI 0.22-0.81) were associated with a lower risk of death. The IBI was associated with postoperative complications and mortality among GC patients undergoing multimodal treatment.

6.
Sensors (Basel) ; 24(3)2024 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-38339669

RESUMO

In this paper, we propose the application of a new geometric procedure in order to calculate a set of transmission zeros of a propagation environment. Since the transmission zeros play a crucial role in modern communication systems, there is a need to apply the efficient solutions characterized by a maximum speed operation. It turns out that the classical method based on the Smith-McMillan factorization is time-consuming, so its contribution to the detection of transmission zeros could be unsatisfactory. Therefore, in order to fill the gap, we present a new algorithm strictly dedicated to the multivariable telecommunications systems described by the transfer-function approach. Consequently, a set of new achievements resulted, particularly in terms of computational efforts. Indeed, the proposed procedure allows us to overcome obstacles derived from technological limitations. The representative simulation examples confirm the great potential of this new method. Finally, it has been pointed out that the newly introduced geometric-originated approach has significantly reduced the computational burden. Indeed, for the randomly selected matrix of the 5×5 dimension describing the sensor-related propagation environment, two representative scenarios were performed in order to manifest the crucial properties. In the first scenario, the sets of multiple transmission zeros were analyzed, ultimately leading to intriguing results. The Smith-McMillan solution took three times longer to discover the mentioned sets. On the other hand, the second instance brought us the same result. Naturally, the discussed difference has increased as a function of the number of matrix elements. For the square matrices involving 100 components, we have observed the respective differences, both over QI=100 and QII=60. It should be emphasized that the finding derived from the Smith-McMillan factorization corresponds to the geometric-related approach in the context of some mechanisms. This is particularly visible when appointing the greatest common divisors.

7.
Sci Rep ; 14(1): 3978, 2024 02 17.
Artigo em Inglês | MEDLINE | ID: mdl-38368450

RESUMO

The expression of the HER2 (human epidermal growth factor receptor 2) protein in cancer cells is a well-established cancer marker used for diagnostic and therapeutic purposes in modern treatment protocols, especially in breast cancer. The gold-standard immunohistochemical diagnostic methods with the specific anti-HER2 antibodies are utilized in the clinic to measure expression level of the membrane-bound receptor. However, a soluble extracellular domain (ECD) of HER2 is released to the extracellular matrix, thus the blood assays for HER2 measurements present an attractive way for HER2 level determination. There is a need for accurate and validated assays that can be used to correlate the concentration of the circulating HER2 protein with disease clinical manifestations. Here we describe two monoclonal antibodies binding HER2 with a unique sequence of the complementarity-determining regions that recognize HER2 ECD. Development and validation of the sandwich enzyme-linked immunosorbent assay (ELISA) for quantification of the soluble HER2 in a variety of biological samples is also presented. The assay provides HER2 quantitation within a concentrations range from 1.56 to 100 ng/ml with sensitivity at the level of 0.5 ng/ml that meets the expectations for measurements of HER2 in the blood and tumor tissue samples. The method presents satisfactory intra- and inter-assay precision and accuracy for immunochemical quantification of biomarkers in biological samples. The utility of the generated monoclonal anti-HER2 antibodies has been confirmed for use in the precise measurement of HER2 (both cell-bound and soluble) in several types of biological material, including serum, solid tumor tissue, and cell culture medium. Additionally, the developed immunochemical tools have a potential for HER2 detection, not only in a wide range of sample types but also independently of the sample storage/pre-processing, allowing for comprehensive HER2 analysis in tissue (IHC), cultured cells (immunofluorescence) and blood (ELISA).


Assuntos
Anticorpos Monoclonais , Neoplasias da Mama , Humanos , Feminino , Anticorpos Monoclonais/uso terapêutico , Receptor ErbB-2 , Neoplasias da Mama/metabolismo , Ensaio de Imunoadsorção Enzimática/métodos , Células Cultivadas , Biomarcadores Tumorais
8.
Artigo em Inglês | MEDLINE | ID: mdl-38363605

RESUMO

BACKGROUND: The triad "insulin resistance, prediabetes, diabetes" is three independent neologies with characteristic features and development. In addition, each are characterized by progression and the possibility of transition from one form to other. Due to the fact that diabetes is one of the common diseases associated with high rates of disability, it is necessary to improve diagnostic methods and educational regimens for successful prevention and treatment of the disease. OBJECTIVE: We investigated Band 3 protein (B3p) level, osmotic resistance of erythrocytes, the total antioxidant activity (TAA) of blood serum, level of HbA1 in group patients with insulin resistance (IR), prediabetes, and Type 2 Diabetes Mellitus (T2DM) and comparative with health control group. METHODS: We used original, accurate research methods that measure the essence of the studied quantities. RESULTS: Disruptions of glucose and insulin homeostasis ay lead to the initiation of oxidative stress (in our study demonstrated by a decrease of TAA of blood serum) increased redox-sensitive PTP activity and aberrant band 3 phosphorylation, potentially leading to reduced erythrocyte deformability. At the same time glycation of Hb during T2DM may affect its cross-link with membrane proteins, in particular with B3p, and although appears to limit its cross-linking and decrease its clusterization ability, induces alterations in the cytoskeletal matrix, and thereby decrease erythrocytes' osmotic resistance making them more susceptible to hemolysis. CONCLUSIONS: The osmotic resistance of the erythrocytes can be used as a sensitive marker for the detection of the early stages of hyperglycemia (prediabetes). This set of clinical trials will make it possible to identify diseases that make up the triad at an early stage. Early detection of disorders and continued research in this direction will help in the development of a diagnostic scheme for the prevention of such patients. Based on our data, research into anti-oxidation drugs is very important. With the help of the array of studies described in the article and antioxidant treatment, the likelihood of successful treatment will increase.

9.
Sci Rep ; 14(1): 2201, 2024 01 25.
Artigo em Inglês | MEDLINE | ID: mdl-38273032

RESUMO

Due to the difficulties in retrieving both the time-dependent shapes of the vessels and the generation of numerical meshes for such cases, most of the simulations of blood flow in the cardiac arteries use static geometry. The article describes a methodology for generating a sequence of time-dependent 3D shapes based on images of different resolutions and qualities acquired from ECG-gated coronary artery CT angiography. The precision of the shape restoration method has been validated using an independent technique. The original proposed approach also generates for each of the retrieved vessel shapes a numerical mesh of the same topology (connectivity matrix), greatly simplifying the CFD blood flow simulations. This feature is of significant importance in practical CFD simulations, as it gives the possibility of using the mesh-morphing utility, minimizing the computation time and the need of interpolation between boundary meshes at subsequent time instants. The developed technique can be applied to generate numerical meshes in arteries and other organs whose shapes change over time. It is applicable to medical images produced by other than angio-CT modalities.


Assuntos
Vasos Coronários , Hemodinâmica , Humanos , Vasos Coronários/diagnóstico por imagem , Vasos Coronários/cirurgia , Angiografia Coronária/métodos , Próteses e Implantes , Tomografia Computadorizada por Raios X
10.
Nat Commun ; 14(1): 8482, 2023 Dec 20.
Artigo em Inglês | MEDLINE | ID: mdl-38123540

RESUMO

Cleavage and formation of phosphodiester bonds in nucleic acids is accomplished by large cellular machineries composed of both protein and RNA. Long thought to rely on a two-metal-ion mechanism for catalysis, structure comparisons revealed many contain highly spatially conserved second-shell monovalent cations, whose precise function remains elusive. A recent high-resolution structure of the spliceosome, essential for pre-mRNA splicing in eukaryotes, revealed a potassium ion in the active site. Here, we employ biased quantum mechanics/ molecular mechanics molecular dynamics to elucidate the function of this monovalent ion in splicing. We discover that the K+ ion regulates the kinetics and thermodynamics of the first splicing step by rigidifying the active site and stabilizing the substrate in the pre- and post-catalytic state via formation of key hydrogen bonds. Our work supports a direct role for the K+ ion during catalysis and provides a mechanistic hypothesis likely shared by other nucleic acid processing enzymes.


Assuntos
RNA , Spliceossomos , Spliceossomos/metabolismo , RNA/metabolismo , Splicing de RNA , Catálise , Metais/metabolismo , Potássio/metabolismo , Quelantes/metabolismo , Conformação de Ácido Nucleico , Sítios de Ligação , Cátions Monovalentes/metabolismo
11.
Cancers (Basel) ; 15(22)2023 Nov 20.
Artigo em Inglês | MEDLINE | ID: mdl-38001751

RESUMO

The development of therapies for advanced gastric cancer (GC) has made significant progress over the past few years. The identification of new molecules and molecular targets is expanding our understanding of the disease's intricate nature. The end of the classical oncology era, which relied on well-studied chemotherapeutic agents, is giving rise to novel and unexplored challenges, which will cause a significant transformation of the current oncological knowledge in the next few years. The integration of established clinically effective regimens in additional studies will be crucial in managing these innovative aspects of GC. This study aims to present an in-depth and comprehensive review of the clinical advancements in targeted therapy and immunotherapy for advanced GC.

12.
J Neuroinflammation ; 20(1): 275, 2023 Nov 23.
Artigo em Inglês | MEDLINE | ID: mdl-37996909

RESUMO

BACKGROUND: Regulatory T cells (Tregs) are involved in the systemic immune response after ischemic stroke. However, their role remains unclear, and the effect appears to be both neuroprotective and detrimental. Treg suppressor function may result in immunodepression and promote stroke-associated infection (SAI). Thus we assume that the bidirectional effects of Tregs may be in part attributed to the intracellular transcription factor Helios. Tregs with Helios expression (H+ Tregs) constitute 70-90% of all Treg cells and more frequently than Helios-negative Tregs (H- Tregs) express molecules recognized as markers of Tregs with suppressor abilities. METHODS AND RESULTS: We prospectively assessed the circulating Treg population with flow cytometry in 52 subjects on days 1, 3, 10 and 90 after ischemic stroke and we compared the results with those obtained in concurrent age-, sex- and vascular risk factor-matched controls. At all studied time points the percentage of H+ Tregs decreased in stroke subjects-D1: 69.1% p < 0.0001; D3: 62.5% (49.6-76.6), p < 0.0001; D10: 60.9% (56.5-72.9), p < 0.0001; D90: 79.2% (50.2-91.7), p = 0.014 vs. controls: 92.7% (81.9-97.0) and the percentage of H- Tregs increased accordingly. In patients with SAI the percentage of pro-suppressor H+ Tregs on post-stroke day 3 was higher than in those without infection (p = 0.03). After adjustment for confounders, the percentage of H+ Tregs on day 3 independently correlated with SAI [OR 1.29; CI 95%: 1.08-1.27); p = 0.02]. Although the percentage of H+ Tregs on day 3 correlated positively with NIHSS score on day 90 (rS = 0.62; p < 0.01) and the infarct volume at day 90 (rS = 0.58; p < 0.05), in regression analysis it was not an independent risk factor. CONCLUSIONS: On the first day after stroke the proportion of H+ vs. H- Tregs changes in favor of pro-inflammatory H- Tregs, and this shift continues toward normalization when assessed on day 90. A higher percentage of pro-suppressive H+ Tregs on day 3 independently correlates with SAI and is associated positively with NIHSS score, but it does not independently affect the outcome and stroke area in the convalescent phase of stroke.


Assuntos
AVC Isquêmico , Linfócitos T Reguladores , Humanos , Estudos de Casos e Controles , Fatores de Transcrição Forkhead/metabolismo , AVC Isquêmico/metabolismo , Subpopulações de Linfócitos T/metabolismo
13.
Genes Dev ; 37(21-24): 968-983, 2023 Dec 26.
Artigo em Inglês | MEDLINE | ID: mdl-37977822

RESUMO

The spliceosomal gene SF3B1 is frequently mutated in cancer. While it is known that SF3B1 hotspot mutations lead to loss of splicing factor SUGP1 from spliceosomes, the cancer-relevant SF3B1-SUGP1 interaction has not been characterized. To address this issue, we show by structural modeling that two regions flanking the SUGP1 G-patch make numerous contacts with the region of SF3B1 harboring hotspot mutations. Experiments confirmed that all the cancer-associated mutations in these regions, as well as mutations affecting other residues in the SF3B1-SUGP1 interface, not only weaken or disrupt the interaction but also alter splicing similarly to SF3B1 cancer mutations. Finally, structural modeling of a trimeric protein complex reveals that the SF3B1-SUGP1 interaction "loops out" the G-patch for interaction with the helicase DHX15. Our study thus provides an unprecedented molecular view of a protein complex essential for accurate splicing and also reveals that numerous cancer-associated mutations disrupt the critical SF3B1-SUGP1 interaction.


Assuntos
Neoplasias , Spliceossomos , Humanos , RNA Mensageiro/metabolismo , Spliceossomos/genética , Spliceossomos/metabolismo , Fatores de Processamento de RNA/química , Splicing de RNA/genética , Neoplasias/genética , Neoplasias/metabolismo , Mutação , Fosfoproteínas/metabolismo
14.
Cytokine ; 172: 156389, 2023 12.
Artigo em Inglês | MEDLINE | ID: mdl-37852156

RESUMO

BACKGROUND: Tumour development is greatly influenced by the systemic inflammatory response. Inflammatory factors, such as neutrophil-to-lymphocyte ratio (NLR), platelet-to-lymphcyte ratio (PLR), and lymphocyte-to-monocyte ratio (LMR), mirror the balance between systemic inflammation and anti-tumour response. The current investigation examined the predictive and prognostic value of NLR, PLR, and LMR in advanced gastric cancer (GC) patients. METHODS: This study is a retrospective, observational analysis involving 105 GC patients treated with neoadjuvant chemotherapy (NAC). Thestudy population included patients who met the eligibility criteria.The relationship between NLR, PLR, LMR and demographic and clinical variables was assessed using theΧ2test. Survival data were analysed by Kaplan-Meier curves. RESULTS: High NLR levels were associated with more advanced tumour stage.Higher risk of no tumour regression after NAC was observed if a high pretreatment level of NLR or PLR was found. All patients with an increase in NLR after NAC had a significantly higher risk of no tumor response.In groups high (no change), increase, decrease, and low (no change), NLR and PLR OS medians were: 33, 67, 78, and not reached-NR and 34, 29, 36, and NR, respectively. All patients had a significantly higher risk of death if NLR increased after NAC. An increase in post-NAC PLR level was associated with an increased risk of death only if the PLR baseline value was low. CONCLUSION: NLR and PLR are promising predictive and prognostic factors in advanced GC patients treated with NAC.


Assuntos
Neoplasias Gástricas , Humanos , Neoplasias Gástricas/patologia , Estudos Retrospectivos , Terapia Neoadjuvante , Linfócitos/patologia , Prognóstico , Neutrófilos/patologia , Síndrome de Resposta Inflamatória Sistêmica/patologia
15.
Ann Surg ; 278(5): 823-831, 2023 11 01.
Artigo em Inglês | MEDLINE | ID: mdl-37555342

RESUMO

OBJECTIVE: To assess the rate of textbook outcome (TO) and textbook oncological outcome (TOO) in the European population based on the GASTRODATA registry. BACKGROUND: TO is a composite parameter assessing surgical quality and strongly correlates with improved overall survival. Following the standard of treatment for locally advanced gastric cancer, TOO was proposed as a quality and optimal multimodal treatment parameter. METHODS: TO was achieved when all the following criteria were met: no intraoperative complications, radical resection according to the surgeon, pR0 resection, retrieval of at least 15 lymph nodes, no severe postoperative complications, no reintervention, no admission to the intensive care unit, no prolonged length of stay, no postoperative mortality and no hospital readmission. TOO was defined as TO with the addition of perioperative chemotherapy compliance. RESULTS: Of the 2558 patients, 1700 were included in the analysis. TO was achieved in 1164 (68.5%) patients. The use of neoadjuvant chemotherapy [odds ratio (OR) = 1.33, 95% CI: 1.04-1.70] and D2 or D2+ lymphadenectomy (OR = 1.55, 95% CI: 1.15-2.10) had a positive impact on TO achievement. Older age (OR = 0.73, 95% CI: 0.54-0.94), pT3/4 (OR = 0.79, 95% CI: 0.63-0.99), ASA 3/4 (OR = 0.68, 95% CI: 0.54-0.86) and total gastrectomy (OR = 0.56, 95% CI: 0.45-0.70), had a negative impact on TO achievement. TOO was achieved in 388 (22.8%) patients. Older age (OR = 0.37, 95% CI: 0.27-0.53), pT3 or pT4 (OR = 0.52, 95% CI: 0.39-0.69), and ASA 3 or 4 (OR = 0.58, 95% CI: 0.43-0.79) had a negative impact on TOO achievement. CONCLUSIONS: Despite successively improved surgical outcomes, stage-appropriate chemotherapy in adherence to the current guidelines for multimodal treatment of gastric cancer remains poor. Further implementation of oncologic quality metrics should include greater emphasis on perioperative chemotherapy and adequate lymphadenectomy.


Assuntos
Neoplasias Gástricas , Humanos , Neoplasias Gástricas/cirurgia , Excisão de Linfonodo/efeitos adversos , Linfonodos/patologia , Gastrectomia/efeitos adversos , Complicações Pós-Operatórias/etiologia , Estudos Retrospectivos , Resultado do Tratamento
16.
Plant Cell ; 35(11): 3957-3972, 2023 Oct 30.
Artigo em Inglês | MEDLINE | ID: mdl-37497643

RESUMO

DNA double-stranded breaks (DSBs) generated by the Cas9 nuclease are commonly repaired via nonhomologous end-joining (NHEJ) or homologous recombination (HR). However, little is known about unrepaired DSBs and the type of damage they trigger in plants. We designed an assay that detects loss of heterozygosity (LOH) in somatic cells, enabling the study of a broad range of DSB-induced genomic events. The system relies on a mapped phenotypic marker which produces a light purple color (betalain pigment) in all plant tissues. Plants with sectors lacking the Betalain marker upon DSB induction between the marker and the centromere were tested for LOH events. Using this assay, we detected a tomato (Solanum lycopersicum) flower with a twin yellow and dark purple sector, corresponding to a germinally transmitted somatic crossover event. We also identified instances of small deletions of genomic regions spanning the T-DNA and whole chromosome loss. In addition, we show that major chromosomal rearrangements including loss of large fragments, inversions, and translocations were clearly associated with the CRISPR-induced DSB. Detailed characterization of complex rearrangements by whole-genome sequencing and molecular and cytological analyses supports a model in which a breakage-fusion-bridge cycle followed by chromothripsis-like rearrangements had been induced. Our LOH assay provides a tool for precise breeding via targeted crossover detection. It also uncovers CRISPR-mediated chromothripsis-like events in plants.


Assuntos
Cromotripsia , Sistemas CRISPR-Cas/genética , Quebras de DNA de Cadeia Dupla , Reparo do DNA por Junção de Extremidades , Recombinação Homóloga , Solanum lycopersicum/genética
17.
Chemistry ; 29(50): e202301159, 2023 Sep 06.
Artigo em Inglês | MEDLINE | ID: mdl-37310801

RESUMO

Biochemical reactions occurring in highly crowded cellular environments require different means of control to ensure productivity and specificity. Compartmentalization of reagents by liquid-liquid phase separation is one of these means. However, extremely high local protein concentrations of up to 400 mg/ml can result in pathological aggregation into fibrillar amyloid structures, a phenomenon that has been linked to various neurodegenerative diseases. Despite its relevance, the process of liquid-to-solid transition inside condensates is still not well understood at the molecular level. We thus herein use small peptide derivatives that can undergo both liquid-liquid and subsequent liquid-to-solid phase transition as model systems to study both processes. Using solid-state nuclear magnetic resonance (NMR) and transmission electron microscopy (TEM), we compare the structure of condensed states of leucine, tryptophan and phenylalanine containing derivatives, distinguishing between liquid-like condensates, amorphous aggregates and fibrils, respectively. A structural model for the fibrils formed by the phenylalanine derivative was obtained by an NMR-based structure calculation. The fibrils are stabilised by hydrogen bonds and side-chain π-π interactions, which are likely much less pronounced or absent in the liquid and amorphous state. Such noncovalent interactions are equally important for the liquid-to-solid transition of proteins, particularly those related to neurodegenerative diseases.


Assuntos
Amiloide , Peptídeos , Ressonância Magnética Nuclear Biomolecular , Estrutura Secundária de Proteína , Modelos Moleculares , Espectroscopia de Ressonância Magnética , Amiloide/química , Fenilalanina
18.
ISA Trans ; 140: 84-96, 2023 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-37330386

RESUMO

In this paper, a new perfect control law dedicated to nonminimum-phase unstable LTI MIMO systems governed in the continuous-time state-space domain is proposed. Two algorithms are investigated, one of which has turned out to be definitely accurate. Henceforth, the inverse model control-based formula can be applied to any right-invertible plants having more input than output variables. Last, not least, through the application of some generalized inverses, the perfect control procedure guarantees the structural stability behavior even for unstable systems. Thus, the notion of the nonminimum-phase property should be understood in terms of a possible achieveability covering the entire class of LTI MIMO continuous-time plants. Theoretical and practical simulation examples performed in the Matlab/Simulink environment confirm the feasibility of the newly introduced approach.

19.
Int J Mol Sci ; 24(12)2023 Jun 09.
Artigo em Inglês | MEDLINE | ID: mdl-37373091

RESUMO

While gastrointestinal tumors remain a multifactorial and prevalent group of malignancies commonly treated surgically in combination with chemotherapy and radiotherapy, advancements regarding immunotherapeutic approaches continue to occur. Entering a new era of immunotherapy focused on overcoming resistance to preceding therapies caused the emergence of new therapeutic strategies. A promising solution surfaces with a V-domain Ig suppressor of T-cell activation (VISTA), a negative regulator of a T-cell function expressed in hematopoietic cells. Due to VISTA's ability to act as both a ligand and a receptor, several therapeutic approaches can be potentially developed. A broad expression of VISTA was discovered on various tumor-growth-controlling cells, which proved to increase in specific tumor microenvironment (TME) conditions, thus serving as a rationale behind the development of new VISTA-targeting. Nevertheless, VISTA's ligands and signaling pathways are still not fully understood. The uncertain results of clinical trials suggest the need for future examining inhibitor agents for VISTA and implicating a double immunotherapeutic blockade. However, more research is needed before the breakthrough can be achieved. This review discusses perspectives and novel approaches presented in the current literature. Based on the results of the ongoing studies, VISTA might be considered a potential target in combined therapy, especially for treating gastrointestinal malignancies.


Assuntos
Neoplasias do Sistema Digestório , Neoplasias Gastrointestinais , Humanos , Antígenos B7/metabolismo , Neoplasias Gastrointestinais/terapia , Ativação Linfocitária , Imunoterapia/métodos , Microambiente Tumoral
20.
J Org Chem ; 88(13): 8248-8256, 2023 Jul 07.
Artigo em Inglês | MEDLINE | ID: mdl-37224442

RESUMO

Compared to the well-known conjugated (1,3-dipolar) and cross-conjugated (1,4-dipolar) heterocyclic mesomeric betaines (HMBs), semi-conjugated HMBs are unexplored and almost unknown. The three discrete classes of HMB are defined by the connectivity between their ring 2π heteroatoms and the odd-conjugated fragments that complete the ring. A single example of a stable, fully-characterized semi-conjugate HMB has been reported. This study employs the density functional theory (DFT) methodology to investigate the properties of a series of six-membered semi-conjugated HMBs. The electronic character of ring substituents is found to significantly influence the structure and electronic properties of the ring. The aromaticity measured by HOMA and NICS(1)zz indices is increased by π-electron-donating substituents whereas π-electron-withdrawing substituents decrease the calculated aromatic character and ultimately lead to non-planar boat or chair structures. A notable property of all derivatives is the small energy gap between their frontier orbitals.


Assuntos
Betaína , Elétrons , Estrutura Molecular
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