http://repositorio.ufc.br/handle/riufc/24047 2026-04-06T08:08:03Z 2026-04-06T08:08:03Z Brandão, Larisse Cadeira http://repositorio.ufc.br/handle/riufc/85090 2026-03-05T18:59:08Z 2026-01-01T00:00:00Z

Título: Caracterização estrutural e bioquímica da l-asparaginase ans-z de bacillus subtilis e avaliação de sua atividade antiproliferativa em linhagens de células tumorais hematológicas Autor(es): Brandão, Larisse Cadeira Abstract: L-asparaginase catalyzes the hydrolysis of L-asparagine into aspartic acid and ammonia. It is found in animals, plants, and microorganisms and is part of a therapeutic strategy based on the restriction of essential amino acids, as are other enzymes that exploit the dependence of cancer cells on these nutrients to survive. Therefore, microbial sources are preferred for large-scale production due to their efficiency and ease of cultivation. In this study, we recombinantly produced and characterized an L-asparaginase from Bacillus subtilis (Asp- Z). Asp-Z was heterologously expressed in Escherichia coli and purified by affinity chromatography, resulting in a soluble protein with optimal activity at 55 °C and pH 7.5. The kinetic parameters under these conditions were a Km of 0.47 mM and a Vmax of 52.13 U/mg. Asp-Z proved specific for L-asparagine, showing no detectable glutaminase activity, and exhibited antiproliferative effects against hematologic cancer cell lines, particularly RAJI and JURKAT, with IC₅₀ values in the micromolar range. In silico analyses revealed distinct immunogenic epitopes between Asp-Z and commercial E. coli L-asparaginase, suggesting divergent antigenic profiles, while crystallographic data revealed a conserved tetrameric structure with a highly flexible active site loop. Taken together, these findings highlight Asp-Z as a thermostable enzyme, free of glutaminase activity and with low immunogenicity, representing a promising structure for optimization through protein engineering, targeting therapeutic and biotechnological applications. Tipo: Tese

2026-01-01T00:00:00Z Araujo, Francisco Jonathan dos Santos http://repositorio.ufc.br/handle/riufc/83184 2025-10-21T20:18:55Z 2025-01-01T00:00:00Z

Título: Cribriform morphology in prostate cancer: an integrated approach combining digital pathology and transcriptomic analysis Autor(es): Araujo, Francisco Jonathan dos Santos Abstract: Cribriform morphology has been increasingly recognized as a histological marker of aggressiveness in prostate cancer, being associated with a higher risk of recurrence, metastasis, and cancer-specific mortality. However, the molecular mechanisms underlying this architectural pattern remain poorly understood. This thesis proposes a multidimensional approach to investigate the morphological and molecular determinants associated with tumor aggressiveness in prostate cancer, with a particular focus on cribriform architecture. In the first chapter, 72 radical prostatectomy samples were analyzed using quantitative digital pathology. Through whole-slide imaging and the QuPath software, immunohistochemical markers PTEN, Ki-67, ATM, and CD8 and key morphological features—such as Gleason pattern 4 percentage, tumor extent, and cribriform morphology—were quantified. The analysis identified a group of markers associated with increased tumor aggressiveness, with cribriform morphology showing significant correlation with higher pathological stage and absence of organ confinement. A logistic regression model combining Gleason pattern 4 percentage and ATM expression accurately predicted the presence of cribriform morphology (AUC = 0.79). In the second chapter, an in silico RNA-Seq analysis was conducted using publicly available data (GEO- NCBI) to characterize the gene expression profile associated with cribriform morphology. A total of 55 differentially expressed genes were identified between cribriform and non- cribriform tumors. Genes such as CPNE4, PLA2G7, PTPRJ, GCNT1, AMACR, AR, and ERG were linked to immune evasion, lipid metabolism, and hormonal signaling pathways. Functional enrichment analysis revealed transcriptional reprogramming consistent with aggressive tumor behavior. Although methodologically independent, the two chapters present complementary findings that reinforce the association between cribriform morphology and a biologically aggressive phenotype in prostate cancer, contributing to the identification of prognostic biomarkers and potential therapeutic targets Tipo: Tese

2025-01-01T00:00:00Z Albuquerque, Aline de Oliveira http://repositorio.ufc.br/handle/riufc/80786 2025-05-08T19:19:19Z 2025-01-01T00:00:00Z

Título: Desenho de biobetters baseados no anticorpo anti-Notch1 Brontictuzumabe usando abordagens de otimização in silico Autor(es): Albuquerque, Aline de Oliveira Abstract: Cancer, one of the leading causes of global mortality, represents a set of diseases with multifactorial etiologies that encompass genetic and epigenetic alterations, including mutations in cell signaling pathways such as Notch, crucial for processes such as differentiation and apoptosis. Activating mutations or overexpression of the Notch1 receptor, for example, are found in patients with chronic lymphocytic leukemia, diffuse large B-cell lymphoma, and adenoid cystic carcinoma. In this context, the monoclonal antibody Brontictuzumab (BRON), which blocks Notch1 activation by binding to its Negative Regulatory Region (NRR), emerges as a promising basis for the development of new biobetters with therapeutic potential. This study aimed to computationally design new antibodies based on Brontictuzumab, focusing on affinity maturation and the proposal of single-chain fragment variables (scFvs), with the goal of enhancing its therapeutic potential. Initially, the three-dimensional structure of BRON was modeled and used to predict interactions with NRR through molecular docking. The complex was simulated via molecular dynamics, with interaction and dissociation energy predictions. The predominant conformations identified were used for optimizations through saturation mutagenesis, CDR grafting, inverse folding and generalized language models. Solubility and other development parameters for therapeutic antibodies were evaluated. BRON-based scFvs were also modeled and their interactions analyzed. Thus, the binding mode of the BRON-NRR complex was identified, suggesting a new inhibition mechanism mediated by BRON's CDR-H2, which reduces accessibility to the S2 cleavage site, essential for Notch1 activation. A total of 10,072 mutants were tested, identifying hot spots in residues such as Thr28, Thr74, Gly101, and Gly104 in the heavy chain and Gly52 in the light chain. The AbSeldon R3 design demonstrated stability, solubility and ΔGbind comparable to native BRON, increasing the participation of the light chain at the interface and being compatible with biophysical parameters of other therapeutic antibodies. Among the scFvs constructed, the one with a 12-amino acid linker showed stability and interactions with S2. Thus, this work resulted in the proposal of promising biobetters, paving the way for new anti-Notch1 antineoplastic therapies based on Brontictuzumab. Keywords: Notch; Brontictuzumab; biobetter. Tipo: Tese

2025-01-01T00:00:00Z Marques, Gabriela Fernandes Oliveira http://repositorio.ufc.br/handle/riufc/78841 2024-11-11T16:37:18Z 2020-01-01T00:00:00Z

Título: Estudo da toxicidade e da atividade anti-inflamatória do chá e dos polissacarídeos obtidos das cascas de Ximenia americana L. em modelos de inflamação aguda e artrite induzidos por zimosan em roedores Autor(es): Marques, Gabriela Fernandes Oliveira Abstract: Rheumatoid arthritis (RA) is a severe arthropathy that affects 0.5-1% of world population, characterized by peripheral joints impairement, persistent synovitis and pain. The therapeutical approach of this pathology includes anti-inflammatory/analgesic drugs and implies high costs, and involving serious side effects. The use of medicinal plants has been a universal popular practice, which enables them as tools of ethnopharmacological studies. Ximenia americana (Olacaceae family) or “ameixa-do-sertão” is used popularly in Northeast Brazil, contains a diversity of bioactive compounds, including polysaccharides. Several parts of the plant are used in folk medicine to treat inflammatory and/or painful disorders. Studies involving experimental models of acute and chronic inflammation in rodents, have demonstrated anti-inflammatory action of its aqueous and hydroethanolic extracts. Additionally, the aqueous extract and the polysaccharide fractions showed antinociceptive action in a model of pancreatitis in mice. In addition, tea of the barks inhibits inflammatory parameters in an experimental gastritis model. Thus, this study focuses on investigating the effect and mechanisms involved in the anti-inflammatory action of tea and polysaccharides from the barks of Ximenia americana in models of acute inflammation and arthritis induced by zimosan, as well as the toxicity resulting from its treatment. Tea (50, 100, 150 mg/kg; v.o.), containing carbohydrates (44.8%) and polyphenols (28.3%); and polysaccharide fractions (FI, FII: 1 mg/kg; e.v.) were administered to Swiss Mice before (induction of edema or peritonitis) or to Wistar Rats after (arthritis induction) stimulation with zimosan. Then, the evaluations of the inflammatory parameters (edema, cell migration, hypernociception, histopathological analyzes) were made from 0 to 24 hours, and until the 14th day, for others evaluations (hematological, plasma biochemical, histopathological and behavioral parameters). The results of the study showed that tea and polysaccharides from X. americana inhibited inflammatory parameters such as edema, cell migration and pain, both visceral and articular, induced by zimosan. In addition, the data also suggest that the use of tea by mouth is relatively safe, as it has not shown any lethality, or has induced significant physiological and/or behavioral changes in animals. This study is relevant because it scientifically validates the popular use of this plant in inflammatory and painful processes. Tipo: Tese

2020-01-01T00:00:00Z