Análise de assinaturas mutacionais no prognóstico de pacientes com adenocarcinoma gástrico e infecção por EBV / Mutational signature analysis in gastric cancer patients' prognosis and EBV infection

Adenocarcinoma gástrico (AdG) possui uma alta incidência na população mundial e brasileira. É um tipo tumoral cujos sintomas são bastante inespecíficos no seu início, resultando no diagnóstico já em estadios avançados. Recentemente, foi proposta uma nova classificação, estratificando o AdG em quatro subtipos, sendo um deles caracterizado pela infecção pelo Epstein Barr vírus (EBV). Neste subtipo, por sua vez, não são totalmente conhecidos os mecanismos subjacentes à infecção, os quais podem estar relacionados à instabilidade genômica e mecanismos adicionais de tumorigênese. Deste modo, o presente estudo fez uso de abordagens de Bioinformática para análise de dados públicos (TCGA) e sua validação no painel gênico de pacientes com AdG do A.C.Camargo Cancer Center, buscando assinaturas mutacionais relacionadas à instabilidade genômica na presença de EBV. A partir dos dados obtidos do consórcio TCGA, observamos expressão aumentada de APOBEC3s no subtipo molecular de AdG EBV positivo. Também foi possível ver maior taxa mutacional, no contexto TCW, nesse subtipo molecular, condizente com a ação de APOBECs. Na coorte do A.C.Camargo Cancer Center, foram obtidas amostras de tecido e de suco gástrico de 240 pacientes com AdG (caso) e 137 controles saudáveis. Nos pacientes caso, foi possível observar 6% de amplificação de fragmento de EBV na biópsia e 11,1% no Suco Gástrico. Os achados do TCGA foram validados na coorte do hospital, utilizando painel gênico. Foi possível cofirmar que a ação da família APOBEC3 está mais presente em amostras EBV positivas, indicando a ação viral na instabilidade gênica em AdG, através da família APOBEC

Gastric adenocarcinoma (GA) is highly frequent in the world and in Brazilian population. It's symptoms are rather nonspecific in the beginning, being diagnosed in advanced stages. Recently, a new classification was proposed, stratifying GA in four subtypes, one characterized by Epstein Barr Virus (EBV) infection. Yet, in this subtype, the underlying mechanisms of infection are not fully understood, which may be related to genomic instability and additional mechanisms of tumorigenesis. Thus, the present study made use of Bioinformatics approaches for public data analysis (TCGA) and its validation in the gene panel of A.C.Camargo Cancer Center patients with GA, searching for mutational signatures related to genomic instability in the presence of EBV. Analysing data from TCGA consortium, we observed increased expression of APOBEC3s in the EBV positive GA molecular subtype. It was also possible to observe a higher mutational rate, in TCW context, in GA with EBV infection, consistent with APOBECs action. In A.C.Camargo Cancer Center cohort, tissue samples and gastric juice were collected from 240 GA patients (case) and 137 healthy controls. It was possible to observe 6% EBV fragment amplification in biopsy and 11.1% in Gastric Juice. TCGA findings were validated in the hospital cohort, by gene panel. It was possible to confirm that APOBEC3 family members are more abundant in EBV positive samples, indicating a viral action in GA genomic instability through APOBEC3 members

H2O2 promotes neutrophil adherence and injury of human umbilical vein endothelial cells / 生理学报

To explore the role of hydrogen peroxide (H2O2) in promoting polymorphonuclear neutrophils adherence and injury of human umbilical vein endothelial cells (HUVECs), the ordinary optical microscope and scanning electron microscopy were used to observe the adherence and injury after HUVECs co-cultured with neutrophils pretreated by extracellular H2O2 (HUVECs and neutrophils co-culture without H2O2 pretreatment as control), and the adhesion rates of neutrophils were measured through cell count test. The percentages of HUVECs expressing intercellular adhesion molecule 1 (ICAM-1) and Apo2.7 were detected by flow cytometry. After being cocultured with the neutrophils pretreated by extracellular H2O2, HUVECs showed obvious injury changes, such as round or oval shape, shortened or disappeared microvilli, and membrane structural damage; The adhesion rate of neutrophils was (57.74 ± 9.18)%, which was significantly higher than that in control [(23.12 ± 6.43)%, P < 0.01, n = 8]; The percentages of HUVECs expressing ICAM-1 and Apo2.7 were (44.69 ± 1.52)% and (39.29 ± 1.81)% respectively, which were significantly higher than those in control [(21.79 ± 1.43)% and (9.79 ± 1.43)%] (P < 0.01, n = 8). The results suggest that extracellular H2O2 can promote the neutrophils adherence and injury of HUVECs.