Navegando por Autor "Vidal, Amanda Ferreira"

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Exome sequencing of native populations from the Amazon reveals patterns on the peopling of South America
(Frontiers Media SA, 2020-10-29) Ribeiro-dos-Santos, André M.; Vidal, Amanda Ferreira; Vinasco-Sandoval, Tatiana; Guerreiro, João; Santos, Sidney; Ribeiro-dos-Santos, Ândrea; Souza, Sandro José de
Studies on the peopling of South America have been limited by the paucity of sequence data from Native Americans, especially from the east part of the Amazon region. Here, we investigate the whole exome variation from 58 Native American individuals (eight different populations) from the Amazon region and draw insights into the peopling of South America. By using the sequence data generated here together with data from the public domain, we confirmed a strong genetic distinction between Andean and Amazonian populations. By testing distinct demographic models, our analysis supports a scenario of South America occupation that involves migrations along the Pacific and Atlantic coasts. Occupation of the southeast part of South America would involve migrations from the north, rather than from the west of the continent
Identification of NUDT15 gene variants in Amazonian Amerindians and admixed individuals from northern Brazil
(2020-04-15) Rodrigues, Juliana Carla Gomes; Souza, Tatiane Piedade de; Pastana, Lucas Favacho; Santos, André Maurício Ribeiro dos; Fernandes, Marianne Rodrigues; Pinto, Pablo; Wanderley, Alayde Vieira; Souza, Sandro José de; Kroll, José Eduardo; Pereira, Adenilson Leão; Magalhães, Leandro; Mercês, Laís Reis das; Vidal, Amanda Ferreira; Vinasco-Sandoval, Tatiana; Cavalcante, Giovanna Chaves; Guerreiro, João Farias; Assumpção, Paulo Pimentel de; Ribeiro-dos-Santos, Ândrea; Santos, Sidney; Santos, Ney Pereira Carneiro dos
Introduction The nudix hydrolase 15 (NUDT15) gene acts in the metabolism of thiopurine, by catabolizing its active metabolite thioguanosine triphosphate into its inactivated form, thioguanosine monophosphate. The frequency of alternative NUDT15 alleles, in particular those that cause a drastic loss of gene function, varies widely among geographically distinct populations. In the general population of northern Brazilian, high toxicity rates (65%) have been recorded in patients treated with the standard protocol for acute lymphoblastic leukemia, which involves thiopurine-based drugs. The present study characterized the molecular profile of the coding region of the NUDT15 gene in two groups, non-admixed Amerindians and admixed individuals from the Amazon region of northern Brazil. Methods The entire NUDT15 gene was sequenced in 64 Amerindians from 12 Amazonian groups and 82 admixed individuals from northern Brazil. The DNA was extracted using phenol-chloroform. The exome libraries were prepared using the Nextera Rapid Capture Exome (Illumina) and SureSelect Human All Exon V6 (Agilent) kits. The allelic variants were annotated in the ViVa® (Viewer of Variants) software. Results Four NUDT15 variants were identified: rs374594155, rs1272632214, rs147390019, andrs116855232. The variants rs1272632214 and rs116855232 were in complete linkage disequilibrium, and were assigned to the NUDT15*2 genotype. These variants had high frequencies in both our study populations in comparison with other populations catalogued in the 1000 Genomes database. We also identified the NUDT15*4 haplotype in our study populations, at frequencies similar to those reported in other populations from around the world. Conclusion Our findings indicate that Amerindian and admixed populations from northern Brazil have high frequencies of the NUDT15 haplotypes that alter the metabolism profile of thiopurines.
Incidence of hereditary gastric cancer may be much higher than reported
(MDPI AG, 2022-12) Assumpção, Paula Baraúna de; Assumpção, Paulo Pimentel de; Moreira, Fabiano Cordeiro; Santos, Andrea Kely Campos Ribeiro dos; Vidal, Amanda Ferreira; Magalhães, Leandro; Khayat, André Salim; Santos, André Mauricio Ribeiro dos; Cavalcante, Giovanna Chaves; Pereira, Adenilson Leão; Medeiros, Inácio Gomes; Souza, Sandro José de; Burbano, Rommel Mario Rodríguez; Souza, Jorge Estefano Santana de; Santos, Sidney Emanuel Batista dos
Hereditary gastric cancers (HGCs) are supposed to be rare and difficult to identify. Nonetheless, many cases of young patients with gastric cancer (GC) fulfill the clinical criteria for considering this diagnosis but do not present the defined pathogenic mutations necessary to meet a formal diagnosis of HGC. Moreover, GC in young people is a challenging medical situation due to the usual aggressiveness of such cases and the potential risk for their relatives when related to a germline variant. Aiming to identify additional germline alterations that might contribute to the early onset of GC, a complete exome sequence of blood samples from 95 GC patients under 50 and 94 blood samples from non-cancer patients was performed and compared in this study. The number of identified germline mutations in GC patients was found to be much higher than that from individuals without a cancer diagnosis. Specifically, the number of high functional impact mutations, including those affecting genes involved in medical diseases, cancer hallmark genes, and DNA replication and repair processes, was much higher, strengthening the hypothesis of the potential causal role of such mutations in hereditary cancers. Conversely, classically related HGC mutations were not found and the number of mutations in genes in the CDH1 pathway was not found to be relevant among the young GC patients, reinforcing the hypothesis that existing alternative germline contributions favor the early onset of GC. The LILRB1 gene variants, absent in the world's cancer datasets but present in high frequencies among the studied GC patients, may represent essential cancer variants specific to the Amerindian ancestry's contributions. Identifying non-reported GC variants, potentially originating from under-studied populations, may pave the way for additional discoveries and translations to clinical interventions for GC management. The newly proposed approaches may reduce the discrepancy between clinically suspected and molecularly proven hereditary GC and shed light on similar inconsistencies among other cancer types. Additionally, the results of this study may support the development of new blood tests for evaluating cancer risk that can be used in clinical practice, helping physicians make decisions about strategies for surveillance and risk-reduction interventions
Role of miRNAs in sigmoid colon cancer: a search for potential biomarkers
(MDPI, 2020-11-10) Correa, Romualdo da Silva; Marques, Diego; Costa, Layse Raynara Ferreira; Costa, Lorenna Larissa Ferreira; Oliveira, Ana Beatriz Bezerra; Ramos, Carlos Cesar de Oliveira; Sandoval, Tatiana Vinasco; Lopes, Katia de Paiva; Vialle, Ricardo Assunção; Vidal, Amanda Ferreira; Silbiger, Vivian Nogueira; Santos, Ândrea Ribeiro dos
The aberrant expression of microRNAs in known to play a crucial role in carcinogenesis. Here, we evaluated the miRNA expression profile of sigmoid colon cancer (SCC) compared to adjacent-to-tumor (ADJ) and sigmoid colon healthy (SCH) tissues obtained from colon biopsy extracted from Brazilian patients. Comparisons were performed between each group separately, considering as significant p-values < 0.05 and |Log2(Fold-Change)| > 2. We found 20 differentially expressed miRNAs (DEmiRNAs) in all comparisons, two of which were shared between SCC vs. ADJ and SCC vs. SCH. We used miRTarBase, and miRTargetLink to identify target-genes of the differentially expressed miRNAs, and DAVID and REACTOME databases for gene enrichment analysis. We also used TCGA and GTEx databases to build miRNA-gene regulatory networks and check for the reproducibility in our results. As findings, in addition to previously known miRNAs associated with colorectal cancer, we identified three potential novel biomarkers. We showed that the three types of colon tissue could be clearly distinguished using a panel composed by the 20 DEmiRNAs. Additionally, we found enriched pathways related to the carcinogenic process in which miRNA could be involved, indicating that adjacent-to-tumor tissues may be already altered and cannot be considered as healthy tissues. Overall, we expect that these findings may help in the search for biomarkers to prevent cancer progression or, at least, allow its early detection, however, more studies are needed to confirm our results.

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Navegando por Autor "Vidal, Amanda Ferreira"