Kinase inhibitor screening reveals aurora-a kinase is a potential therapeutic and prognostic biomarker of gastric cancer.

Gastric cancer is one of the most common and deadly types of cancer in the world, and poor prognosis with treatment failure is widely reported in the literature. In this context, kinases have been considered a relevant choice for targeted therapy in gastric cancer. Here, we explore the antiproliferative and antimigratory effects of the AURKA inhibitor and the prognostic and therapeutic value as a biomarker of gastric cancer. A total of 145 kinase inhibitors were screened to evaluate the cytotoxic or cytostatic effects in the gastric cancer cell line. Using the Alamar Blue assay, flow cytometry, quantitative polymerase chain reaction, and observation of caspase 3/7 activity and cell migration, we investigated the antiproliferative, proapoptotic, and antimigratory effects of the AURKA inhibitor. Moreover, AURKA overexpression was evaluated in the gastric cell lines and the gastric tumor tissue. Out of the 145 inhibitors, two presented the highest antiproliferative effect. Both molecules can induce apoptosis by the caspases 3/7 pathway in addition to inhibiting cancer cell migration, mainly the AURKA inhibitor. Moreover, molecular docking analysis revealed that GW779439X interacts in the active site of the AURKA enzyme with similar energy as a well-described inhibitor. Our study identified AURKA overexpression in the gastric cancer cell line and gastric tumor tissue, revealing that its overexpression in patients with cancer is correlated with low survival. Therefore, it is feasible to suggest AURKA as a potential marker of gastric cancer, besides providing robust information for diagnosis and estimated survival of patients. AURKA can be considered a new molecular target used in the prognosis and therapy of gastric cancer.

Effect of APE1 T2197G (Asp148Glu) polymorphism on APE1, XRCC1, PARP1 and OGG1 expression in patients with colorectal cancer.

It has been hypothesized that genetic variation in base excision repair (BER) might modify colorectal adenoma risk. Thus, we evaluated the influence of APE1 T2197G (Asp148Glu) polymorphism on APE1, XRCC1, PARP1 and OGG1 expression in normal and tumor samples from patients with colorectal cancer. The results indicate a downregulation of OGG1 and an upregulation of XRCC1 expression in tumor tissue. Regarding the anatomical location of APE1, OGG1 and PARP-1, a decrease in gene expression was observed among patients with cancer in the rectum. In patients with or without some degree of tumor invasion, a significant downregulation in OGG1 was observed in tumor tissue. Interestingly, when taking into account the tumor stage, patients with more advanced grades (III and IV) showed a significant repression for APE1, OGG1 and PARP-1. XRCC1 expression levels were significantly enhanced in tumor samples and were correlated with all clinical and histopathological data. Concerning the polymorphism T2197G, GG genotype carriers exhibited a significantly reduced expression of genes of the BER repair system (APE1, XRCC1 and PARP1). In summary, our data show that patients with colorectal cancer present expression changes in several BER genes, suggesting a role for APE1, XRCC1, PARP1 and OGG1 and APE1 polymorphism in colorectal carcinogenesis.

Effect of MLH1 -93G>A on gene expression in patients with colorectal cancer.

The DNA repair machinery plays a key role in maintaining genomic stability by preventing the emergence of mutations. Furthermore, the -93G>A polymorphism in the MLH1 gene has been associated with an increased risk of developing colorectal cancer. Therefore, the aim of this study was to examine the expression pattern and effect of this polymorphism in normal and tumour samples from patients with colorectal cancer. The MLH1 -93G>A (rs1800734) polymorphism was detected by PCR-RFLP in 49 cases of colorectal cancer. MLH1 expression was investigated using real-time quantitative PCR. The results indicate a significant decrease in MLH1 expression in tumour samples compared to their normal counterparts. The MLH1 gene was also significantly repressed in samples from patients who had some degree of tumour invasion into other organs. Similarly, those patients who were in a more advanced tumour stage (TNM III and IV) exhibited a significant reduction in MLH1 gene expression. Finally, the mutant genotype AA of MLH1 was associated with a significant decrease in the expression of this gene. This finding suggests that this polymorphism could increase the risk of developing colorectal cancer by a defective mismatch repair system, particularly through the loss of MLH1 expression in an allele-specific manner.

TP53 mutations in astrocytic gliomas: an association with histological grade, TP53 codon 72 polymorphism and p53 expression.

TP53 mutations and polymorphisms have been widely related to many cancers as long as these alterations may impair its capacity to induce cell cycle arrest, DNA repair mechanisms, and apoptosis. Although TP53 alterations have been studied in astrocytic tumors, there is a lack of analysis considering specific TP53 mutations and their associations with p53 immunostainning, polymorphisms and their significance among the histological grades. Thus, we analyzed TP53 alterations in exons 2-11, including the codon 72 polymorphism, using DNA sequencing in 96 astrocytic gliomas (18 grade I, 20 grade II, 14 grade III, and 44 grade IV). Also, immunohistochemistry was assessed to evaluate the p53 protein expression. In this study, we found that the higher histological grades were statistically associated with TP53 mutations. Some of these mutations, such as TP53 P98T and TP53 G244S, seemed to be a specific marker for the higher grades, and the TP53 E286K mutation appears to be a World Health Organization grade III-IV progression marker. Also, the TP53 P98T mutation, in exon 4, is very likely to be important on the stabilization of the p53 protein, leading to its immunopositivity and it is potentially associated with the TP53 72Pro/Pro genotype.

Interrelationship between TP53 gene deletion, protein expression and chromosome 17 aneusomy in gastric adenocarcinoma.

BACKGROUND: This study evaluates the existence of numerical alterations of chromosome 17 and TP53 gene deletion in gastric adenocarcinoma. The p53 protein expression was also evaluated, as well as, possible associations with clinicopathological characteristics. METHODS: Dual-color fluorescence in situ hybridization and immunostaining were performed in twenty gastric cancer samples of individuals from Northern Brazil. RESULTS: Deletion of TP53 was found in all samples. TP53 was inactivated mainly by single allelic deletion, varying to 7-39% of cells/case. Aneusomy of chromosome 17 was observed in 85% of cases. Chromosome 17 monosomy and gain were both observed in about half of cases. Cells with gain of chromosome 17 frequently presented TP53 deletion. The frequency of cells with two chr17 and one TP53 signals observed was higher in diffuse than in intestinal-type GC. Immunoreactivity of p53 was found only in intestinal-type samples. The frequency of cells with two chr17 and two TP53 signals found was higher in samples with positive p53 expression than in negative cases in intestinal-type GC. CONCLUSION: We suggest that TP53 deletion and chromosome 17 aneusomy is a common event in GC and other TP53 alterations, as mutation, may be implicated in the distinct carcinogenesis process of diffuse and intestinal types.

Fatores de risco associados a trombose em pacientes do estado do Ceará / Risk factors of thrombosis in patients of the state of Ceará

Trombose refere-se à formação de constituintes sanguíneos de massa anormal dentro dos vasos e envolve a interação de fatores vasculares, celulares e humorais na corrente sanguínea circulante e pode desenvolver-se em artérias ou veias, sendo designada arterial ou venosa. Tanto a trombose arterial quanto a venosa são patologias de grande interesse médico com alto índice de morbidade e mortalidade. Este estudo objetivou verificar a associação de fatores de risco e o desenvolvimento de trombose venosa e arterial em pacientes do Centro de Hematologia e Hemoterapia do Estado do Ceará (Hemoce). Foram entrevistados 189 pacientes com eventos tromboembólicos e 349 voluntários saudáveis quanto aos fatores ambientais sabidamente envolvidos no desenvolvimento de trombose. Em análises univariadas e multivariadas, fumo (OR- 17,3, 14,9 e 33,3), o álcool (OR- 6,4, 5,8 e 13,5), a idade acima de 40 anos (OR-2) e o sexo feminino (OR- 3,7 e 4,1) foram estatisticamente significativos. O uso do fumo e do álcool, a idade avançada e o sexo feminino contribuíram para a ocorrência de trombose nos pacientes do estado do Ceará.

Thrombosis is the development of a solid mass or plug formed in the living heart or vessels from constituents of the blood and involves vascular, cells and humors factors. Arterial and venous thrombosis are very interesting of medicine because of the high-risk mortality and morbidly. This study aimed of to look at the association between of the factors risk and development of arterial and venous thrombosis in patients of the Hemoterapy and Hematology Center of Ceará (Hemoce). The participants comprised 189 patients with thrombo-embolic events and 349 health control group. At univariate multivariate analysis the factors studied, tabagism (OR- 17,3, 14,9 e 33,3), age > 40 years old (OR-2), alchol (OR- 6,4, 5,8 e 13,5) and femele (OR- 3,7 e 4,1) were significant statistic.

Relationship between EBV infection and expression of cellular proteins c-Myc, Bcl-2, and Bax in gastric carcinomas.

BACKGROUND: Epstein-Barr virus (EBV) has been related to tumorigenesis in about 10% of all gastric carcinomas. Several studies have demonstrated strong evidence of its involvement in this process, but most of the mechanisms used by the virus to control this process are still unknown. Previous studies in vitro have indicated a relationship between the virus and some cellular genes involved in processes such as proliferation and apoptosis. OBJECTIVE: The aim of the present study was to investigate a possible EBV-induced tumorigenic pathway involving the cellular proteins Bcl-2, Bax, and c-Myc. STUDY DESIGN: One hundred patients of gastric carcinoma, obtained from 2 hospitals in Fortaleza, Brazil were assessed for the presence of EBV by in situ hybridization, for the expression of Bcl-2, Bax, and c-Myc (nuclear and cytoplasmic staining) proteins by immunohistochemistry techniques, and for the apoptotic index. RESULTS: EBV was detected in 8 (8%) patients showing strong staining situated in the nuclei of the tumor cells, 6 of them displaying a diffuse pattern, and 2 demonstrating a focal pattern of staining. The correlation with the immunohistochemistry results demonstrated that none of the EBV-positive cases exhibited Bcl-2 staining. On the other hand, Bax and c-Myc (nuclear) proteins demonstrated a significant positivity index and staining scores (labeling index and H-score) in the EBV-positive group; however, the values were lower than those obtained in the EBV-negative group, notably for c-Myc nuclear protein. In contrast, the cytoplasmic staining of c-Myc protein revealed slightly higher staining values in the EBV-positive group. The balance between Bcl-2 and Bax proteins demonstrated that the majority of the evaluated cases exhibited apoptosis orientation; however, in 62.5% of the EBV-positive cases neither protein was observed. The average apoptotic index was 4.58%, demonstrating a slightly lower average in the EBV-positive group. CONCLUSIONS: EBV is not related to the overexpression of Bcl-2 and c-Myc (nuclear) in gastric carcinomas; however, the results point to a possible EBV involvement with the transport mechanisms of the nuclear membrane, resulting in cytoplasmic c-Myc accumulation. The suppression of Bax expression could represent an alternative viral mechanism for inhibition of apoptosis.

Expression of Ki-67, topoisomerase IIalpha and c-MYC in astrocytic tumors: correlation with the histopathological grade and proliferative status.

Astrocytomas represent the most frequent primary tumors of the central nervous system. Recently, the determination of the proliferative index of astrocytic tumors by different methods has been proposed as a valuable tool for tumor grading and also as a prognostic marker. The aim of the present study was to evaluate the expression of cell proliferation-related proteins in human astrocytic tumors of different histopathological grades (WHO). An immunohistochemical study of the Ki-67, Topoisomerase IIalpha (Topo IIalpha) and c-MYC proteins using the avidin-biotin-peroxidase method was performed in 55 astrocytomas (13 grade I, 14 grade II, 7 grade III and 21 grade IV) and five samples of non-tumor brain tissue (control group). Ki-67, Topo IIalpha and c-MYC positive indices tended to increase according to malignant progression, were absent in non-tumor brain tissue and showed maximum values in high-grade astrocytomas (III and IV). A gradual increase in Ki-67 antigen expression was observed in agreement with mitotic index and histopathological classification. The same was not observed for Topo IIalpha and c-MYC. Ki-67 antigen detection in more than 8.0% of the tumor cells distinguished astrocytoma grade IV, while a labeling index between 1.5 and 8.0% characterized astrocytomas grade III and values below 1.5% discriminated low-grade tumors (I and II). These results indicate that Topo IIalpha and c-MYC expression is associated with cell proliferation in astrocytomas, although not in an exclusive way. Moreover, Ki-67 antigen was found to be the best marker of cellular proliferation, and its expression predicts the grade of astrocytic tumors.

Rastreamento familiar do fator V de Leiden: a importância da deteccão de portadores heterozigotos / Familiar tracking of factor V Leiden: the importance of detection in heterozygous carriers

O fator de Leiden é uma mutacão genética que predispõe seus portadores ao tromboembolismo venoso. O objetivo do estudo foi investigar a distribuicão dos alelos em 21 membros da família de três pacientes portadores de trombose com a presenca da mutacão do fator V de Leiden. A deteccão da mutacão no gene do fator V foi realizada entre portadores da mutacão no estado heterozigoto. Este estudo foi realizado no Centro de Hematologia e Hemoterapia do Ceará - Hemoce. Observou-se a presenca da mutacão no estado heterozigoto na família 1 (83,3 por cento), na família 2 (40 por cento) e na família 3 (50 por cento). No total de 24 membros (pacientes e familiares) analisados, 50 por cento (12/24) apresentaram a mutacão, todos no estado heterozigoto, 66,7 por cento (8/12) não apresentaram trombose. A deteccão do fator V de Leiden em pacientes portadores de eventos trombóticos é recomendado para esclarecimento das causas e para efetuar o rastreamento em membros de sua família, ainda sem o aparecimento de eventos trombóticos, de forma a avaliar os riscos associados e assim determinar um acompanhamento médico preventivo.