Avaliação de tecnologias e dispositivos para a bioimpressão 3D de tecidos aplicados à área médica

A tecnologia de bioimpressão 3D é uma tecnologia inovadora que possui diversas aplicabilidades na área da saúde. Na área médica, a bioimpressão 3D é utilizada para produção de peças cirúrgicas, implantações e produção de próteses, e para fabricação de tecidos e órgãos. O objetivo deste estudo foi destrinchar os dados acerca desta tecnologia e sua atual aplicabilidade na área médica. O método consistiu na condução de uma revisão bibliográfica da literatura sobre as tecnologias de bioimpressão 3D na área de ciências da saúde, de acordo com os parâmetros determinados pela declaração PRISMA. Os resultados da revisão demonstraram que a tecnologia tem sido bastante inovadora e importante para o avanço de pesquisas na área médica, porém ainda apresenta alguns entraves para sua implementação na prática clínica como a nutrição tecidual, contaminação de amostra e alguns fatores de expressão dos tecidos. Assim, pode-se afirmar que o tecido bioimpresso é eficiente, uma vez que se assemelha muito bem ao tecido humano. Os estudos de toxicidade em relação a drogas, de investigação de microambiente tecidual e tumoral são de extrema relevância para futuramente gerar tratamentos personalizados e individualizados, melhorando assim a terapia de diversas doenças. Em conclusão, nossa pesquisa demonstrou que os avanços na área de impressão tridimensional permitiram que a tecnologia fosse capaz de imprimir tecidos biológicos vivos e funcionais, de extrema relevância na aplicabilidade médica

Biomarcadores de progressão em carcinomas orais

Os carcinomas de células escamosas orais (CCEOs) são tumores malignos da cavidade oral que abrangem aproximadamente 50% de todos os cânceres de cabeça e pescoço, e são a sexta causa de morte por câncer em todo o mundo. Acredita-se que 16-62% destes carcinomas se desenvolvam de lesões potencialmente malignas (OPMLs) conhecidas como leucoplasias orais. Embora se saiba que os CCEOs possam se desenvolver a partir de leucoplasias, a avaliação clínica e histológica existente possue um valor prognóstico limitado para predizer quais dessas OPMLs progredirão a carcinoma. Neste contexto, a busca por marcadores genéticos associados ao prognóstico de leucoplasias é importante, uma vez que estes seriam utilizados como ferramentas mais robustas para a predição da transformação maligna das leucoplasias orais. Apesar de alguns estudos mostrarem alterações genéticas envolvidas na progressão do câncer oral, genes capazes de predizer a transformação maligna de leucoplasias à carcinoma permanecem desconhecidos. A aplicação de análises genômicas em ampla escala, como as utilizadas este estudo, possui potencial para superar este problema, uma vez que permite a identificação de genes/vias específicas envolvidos nesta doença. Além disso, a inclusão de amostras sequênciais de leucoplasias que progrediram e CCEOs de um mesmo paciente, permite uma comparação mais acurada de modificações genéticas que ocorrem nestas lesões durante a progressão oral. Para tal, aplicamos a análise de expressão de microRNAs e a análise do número de cópias do DNA para a identificação de alterações genéticas associadas com a progressão do câncer oral. Este estudo foi o primiero a identificar uma assinatura de miRNAs (miR-146a, miR- 181b, miR-184, miR-21, miR-345, miR-518b, miR-520g, miR-649, miR-196a e miR-206) foi identificada como associada com a progressão ao câncer oral...Not Availabl

Activin A triggers angiogenesis via regulation of VEGFA and its overexpression is associated with poor prognosis of oral squamous cell carcinoma

Poor prognosis associated with the dysregulated expression of activin A in a number of malignancies has been related to with numerous aspects of tumorigenesis, including angiogenesis. The present study investigated the prognostic significance of activin A immunoexpression in blood vessels and cancer cells in a number of oral squamous cell carcinoma (OSCC) cases and appliedin vitrostrategies to determine the impact of activin A on angiogenesis. In a cohort of 95 patients with OSCC, immunoexpression of activin A in both blood vessels and tumor cells was quantified and the association with clinicopathological parameters and survival was analyzed. Effects of activin A on the tube formation, proliferation and migration of human umbilical vein endothelial cells (HUVECs) were evaluated in gain-of-function (treatment with recombinant activin A) or loss-of-function [treatment with activin A-antagonist follistatin or by stable transfection with short hairpin RNA (shRNA) targeting activin A] conditions. Conditioned medium from an OSCC cell line with shRNA-mediated depletion of activin A was also tested. The profile of pro- and anti-angiogenic factors regulated by activin A was assessed with a human angiogenesis quantitative PCR (qPCR) array. Vascular endothelial growth factor A (VEGFA) and its major isoforms were evaluated by reverse transcription-qPCR and ELISA. Activin A expression in blood vessels demonstrated an independent prognostic value in the multivariate analysis with a hazard ratio of 2.47 [95% confidence interval (CI), 1.30-4.71; P=0.006) for disease-specific survival and 2.09 (95% CI, 1.07-4.08l: P=0.03) for disease-free survival. Activin A significantly increased tubular formation of HUVECs concomitantly with an increase in proliferation. This effect was validated by reduced proliferation and tubular formation of HUVECs following inhibition of activin A by follistatin or shRNA, as well as by treatment of HUVECs with conditioned medium from activin A-depleted OSCC cells. Activin A-knockdown increased the migration of HUVECs. In addition, activin A stimulated the phosphorylation of SMAD2/3 and the expression and production of total VEGFA, significantly enhancing the expression of its pro-angiogenic isoform 121. The present fndings suggest that activin A is a predictor of the prognosis of patients with OSCC, and provide evidence that activin A, in an autocrine and paracrine manner, may contribute to OSCC angiogenesis through differential expression of the isoform 121 of VEGFA.Peer reviewe

H19-DMR allele-specific methylation analysis reveals epigenetic heterogeneity of CTCF binding site 6 but not of site 5 in head-and-neck carcinomas:a pilot case-control analysis

Aberrant methylation of seven potential binding sites of the CTCF factor in the differentially methylated region upstream of the H19 gene (H19-DMR) has been suggested as critical for the regulation of IGF2 and H19 imprinted genes. In this study, we analyzed the allele-specific methylation pattern of CTCF binding sites 5 and 6 using methylationsensitive restriction enzyme PCR followed by RFLP analysis in matched tumoral and lymphocyte DNA from head-and-neck squamous cell carcinoma (HNSCC) patients, as well as in lymphocyte DNA from control individuals who were cancer-free. The monoallelic methylation pattern was maintained in CTCF binding site 5 in 22 heterozygous out of 91 samples analyzed. Nevertheless, a biallelic methylation pattern was detected in CTCF binding site 6 in a subgroup of HNSCC patients as a somatic acquired feature of tumor cells. An atypical biallelic methylation was also observed in both tumor and lymphocyte DNA from two patients, and at a high frequency in the control group (29 out of 64 informative controls). Additionally, we found that the C/T transition detected by HhaI RFLP suppressed one dinucleotide CpG in critical CTCF binding site 6, of a mutation showing polymorphic frequencies. Although a heterogeneous methylation pattern was observed after DNA sequencing modified by sodium bisulfite, the biallelic methylation pattern was confirmed in 9 out of 10 HNSCCs. These findings are likely to be relevant in the epigenetic regulation of the DMR, especially in pathological conditions in which the imprinting of IGF2 and H19 genes is disrupted

Combining discovery and targeted proteomics reveals a prognostic signature in oral cancer

Different regions of oral squamous cell carcinoma (OSCC) have particular histopathological and molecular characteristics limiting the standard tumor-node-metastasis prognosis classification. Therefore, defining biological signatures that allow assessing the prognostic outcomes for OSCC patients would be of great clinical significance. Using histopathology-guided discovery proteomics, we analyze neoplastic islands and stroma from the invasive tumor front (ITF) and inner tumor to identify differentially expressed proteins. Potential signature proteins are prioritized and further investigated by immunohistochemistry (IHC) and targeted proteomics. IHC indicates low expression of cystatin-B in neoplastic islands from the ITF as an independent marker for local recurrence. Targeted proteomics analysis of the prioritized proteins in saliva, combined with machine-learning methods, highlights a peptide-based signature as the most powerful predictor to distinguish patients with and without lymph node metastasis. In summary, we identify a robust signature, which may enhance prognostic decisions in OSCC and better guide treatment to reduce tumor recurrence or lymph node metastasis.Peer reviewe

Combining discovery and targeted proteomics reveals a prognostic signature in oral cancer

Abstract Different regions of oral squamous cell carcinoma (OSCC) have particular histopathological and molecular characteristics limiting the standard tumor−node−metastasis prognosis classification. Therefore, defining biological signatures that allow assessing the prognostic outcomes for OSCC patients would be of great clinical significance. Using histopathology-guided discovery proteomics, we analyze neoplastic islands and stroma from the invasive tumor front (ITF) and inner tumor to identify differentially expressed proteins. Potential signature proteins are prioritized and further investigated by immunohistochemistry (IHC) and targeted proteomics. IHC indicates low expression of cystatin-B in neoplastic islands from the ITF as an independent marker for local recurrence. Targeted proteomics analysis of the prioritized proteins in saliva, combined with machine-learning methods, highlights a peptide-based signature as the most powerful predictor to distinguish patients with and without lymph node metastasis. In summary, we identify a robust signature, which may enhance prognostic decisions in OSCC and better guide treatment to reduce tumor recurrence or lymph node metastasis