Percorrer por autor "Prazeres, Hugo"
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- Exploring the genetic links between voltage-gated potassium channels and familial non-medullary thyroid carcinoma: a family studyPublication . Teixeira, Elisabete; Rodrigues, Lia; Cardoso, Marta; Fernandes, Cláudia; Paula, Arnaud da Cruz; Lima, Raquel; Ferreira, Marta; Martins, Teresa; Fernandes, Andreia; Rodrigues, Fernando; Prazeres, Hugo; Soares, Paula; Rodrigues, LiaOur team identified a family where 5 elements developed thyroid cancer between the ages of 26 and 38. Since no syndromic form of the disease was found, the diagnosis was of familial non-medullary thyroid carcinoma (FNMTC). Our team employed Whole-Exome Sequencing (WES) and identified a new potentially pathogenic germline mutation in the KCNB2 gene [ p.(Gly106Arg)]. KCNB2 encodes a voltage-gated potassium channel (vgKCN), and the detected missense mutation is localized in the tetramerization domain of the protein, possibly affecting its assembly and KC efflux. Since KC efflux by the cell is a necessary condition for cellular homeostasis, channel disruption can impact the function of other ion channels nearby. Mice studies showed that KCNE2 disruption indirectly impairs sodium-iodide symporter (NIS) function, and therefore iodide uptake by the cell, resulting in hypothyroidism or follicular nodular disease. Hypothesis By indirect effect on NIS function vgKCN mutations may increase predisposition to thyroid cancer and interfere with radioiodine (RAI) therapy response. We conducted in silico studies using two different NGS databases, TCGA and one in-house oncocytic tumors database (513 and 18 patients, respectively). Alterations in 59 genes were searched for copy-number variation, point mutations and other genetic alterations. in vitro assays using the FRTL-5 cell line are being performed. FRTL-5 cells were transfected with overexpression vectors containing either KCNB2 wild-type or KCNB2 mutated sequences, and the empty vector (EV) as a negative control. Expression of thyroid markers (e.g. NIS, TSH receptor, Thyroglobulin and TPO) was evaluated by qPCR and cell viability by PrestoBlue assay. Protein expression of thyroid markers will be assessed by Western blot. Cell cycle and apoptosis through flow cytometry, cell morphology by phalloidin assay, and cell colony formation by crystal violet. Transformed cells will further be treated with Guangxitoxin-1E, a potent KCNB1 / KCNB2 inhibitor. Our in silico results show that vgKCN mutations are rare events in thyroid cancer [19/488 (4%) in TCGA; 3/18 (17%) in our in-house database]. BRAF and NRAS alterations are frequent events in vgKCN altered tumors (58% and 16%, respectively). No KCNB2 pathogenic mutations were observed. vgKCN mutations were not correlated with patient prognosis. Our in vitro preliminary results show that KCNB2 mutated cells present higher expression of the channel than KCNB2 wild-type cells. No differences in cell viability were found between KCNB2 wild-type and mutated cells. If confirmed, vgKCN mutations may identify patients with altered RAI response, serving as thyroid cancer markers and potential pharmacological targets.
- Frequency of TERT promoter mutations in human cancersPublication . Vinagre, João; Almeida, Ana; Pópulo, Helena; Batista, Rui; Lyra, Joana; Pinto, Vasco; Coelho, Ricardo; Celestino, Ricardo; Prazeres, Hugo; Lima, Luís; Melo, Miguel; Rocha, Adriana Gaspar; Preto, Ana; Castro, Patrícia; Castro, Ligia; Pardal, Fernando; Lopes, José Manuel; Santos, Lúcio; Reis, Rui Manuel; Cameselle-Teijeiro, José; Sobrinho-Simões, Manuel; Lima, Jorge; Máximo, Valdemar; Soares, PaulaReactivation of telomerase has been implicated in human tumorigenesis, but the underlying mechanisms remain poorly understood. Here we report the presence of recurrent somatic mutations in the TERT promoter in cancers of the central nervous system (43%), bladder (59%), thyroid (follicular cell-derived, 10%) and skin (melanoma, 29%). In thyroid cancers, the presence of TERT promoter mutations (when occurring together with BRAF mutations) is significantly associated with higher TERT mRNA expression, and in glioblastoma we find a trend for increased telomerase expression in cases harbouring TERT promoter mutations. Both in thyroid cancers and glioblastoma, TERT promoter mutations are significantly associated with older age of the patients. Our results show that TERT promoter mutations are relatively frequent in specific types of human cancers, where they lead to enhanced expression of telomerase.
- TERT promoter mutations are a major indicator of poor outcome in differentiated thyroid carcinomasPublication . Melo, Miguel; Gaspar Da Rocha, Adriana; Vinagre, João; Batista, Rui; Peixoto, Joana; Tavares, Catarina; Celestino, Ricardo; Almeida, Ana; Salgado, Catarina; Eloy, Catarina; Castro, Patrícia; Prazeres, Hugo; Lima, Jorge; Amaro, Teresina; Lobo, Cláudia; Martins, Maria João; Moura, Margarida; Cavaco, Branca; Leite, Valeriano; Cameselle-Teijeiro, José; Carrilho, Francisco; Carvalheiro, Manuela; Maximo, Valdemar; Sobrinho-Simões, Manuel; Soares, PaulaContext: Telomerase promoter mutations (TERT) were recently described in follicular cell-derived thyroid carcinomas (FCDTC) and seem to be more prevalent in aggressive cancers. Objectives: We aimed to evaluate the frequency of TERT promoter mutations in thyroid lesions and to investigate the prognostic significance of such mutations in a large cohort of patients with differentiated thyroid carcinomas (DTCs). Design: This was a retrospective observational study. Setting and Patients: We studied 647 tumors and tumor-like lesions. A total of 469 patients with FCDTC treated and followed in five university hospitals were included. Mean follow-up (±SD) was 7.8 ± 5.8 years. Main Outcome Measures: Predictive value of TERT promoter mutations for distant metastasization, disease persistence at the end of follow-up, and disease-specific mortality. Results: TERT promoter mutations were found in 7.5% of papillary carcinomas (PTCs), 17.1% of follicular carcinomas, 29.0% of poorly differentiated carcinomas, and 33.3% of anaplastic thyroid carcinomas. Patients with TERT-mutated tumors were older (P < .001) and had larger tumors (P = .002). In DTCs, TERT promoter mutations were significantly associated with distant metastases (P < .001) and higher stage (P < .001). Patients with DTC harboring TERT promoter mutations were submitted to more radioiodine treatments (P = .009) with higher cumulative dose (P = .004) and to more treatment modalities (P = .001). At the end of follow-up, patients with TERT-mutated DTCs were more prone to have persistent disease (P = .001). TERT promoter mutations were significantly associated with disease-specific mortality [in the whole FCDTC (P < .001)] in DTCs (P < .001), PTCs (P = .001), and follicular carcinomas (P < .001). After adjusting for age at diagnosis and gender, the hazard ratio was 10.35 (95% confidence interval 2.01–53.24; P = .005) in DTC and 23.81 (95% confidence interval 1.36–415.76; P = .03) in PTCs. Conclusions: TERT promoter mutations are an indicator of clinically aggressive tumors, being correlated with worse outcome and disease-specific mortality in DTC. TERT promoter mutations have an independent prognostic value in DTC and, notably, in PTC.