Phylogenetic analysis of probable non-human genes of group A rotaviruses isolated from children with acute gastroenteritis in Belém, Brazil.

Rotaviruses (RVs) are the main cause of acute viral gastroenteritis in both humans and young animals of various species such as calves, horses, pigs, dogs, cats, and birds. The genetic diversity of RVs is related to a variety of evolutionary mechanisms, including point mutation, and genome reassortment. The objective of this study was to characterize molecularly genes that encode structural and nonstructural proteins in unusual RV strains. The clinical specimens selected for this study were obtained from children and newborn with RV gastroenteritis, who participated in research projects on viral gastroenteritis conducted at the Evandro Chagas Institute. Structural (VP1-VP4, VP6, and VP7) and nonstructural (NSP1-NSP6) genes were amplified from stool samples by the polymerase chain reaction and subsequently sequenced. Eight unusual RV strains isolated from children and newborn with gastroenteritis were studied. Reassortment between genes of animal origin were observed in 5/8 (62.5%) strains analyzed. These results demonstrate that, although rare, interspecies (animal-human) transmission of RVs occurs in nature, as observed in the present study in strains NB150, HSP034, HSP180, HST327, and RV10109. This study is the first to be conducted in the Amazon region and supports previous data showing a close relationship between genes of human and animal origin, representing a challenge to the large-scale introduction of RV vaccines in national immunization programs.

Influence of the interaction between nodal fibroblast and breast cancer cells on gene expression.

Our aim was to evaluate the interaction between breast cancer cells and nodal fibroblasts, by means of their gene expression profile. Fibroblast primary cultures were established from negative and positive lymph nodes from breast cancer patients and a similar gene expression pattern was identified, following cell culture. Fibroblasts and breast cancer cells (MDA-MB231, MDA-MB435, and MCF7) were cultured alone or co-cultured separated by a porous membrane (which allows passage of soluble factors) for comparison. Each breast cancer lineage exerted a particular effect on fibroblasts viability and transcriptional profile. However, fibroblasts from positive and negative nodes had a parallel transcriptional behavior when co-cultured with a specific breast cancer cell line. The effects of nodal fibroblasts on breast cancer cells were also investigated. MDA MB-231 cells viability and migration were enhanced by the presence of fibroblasts and accordingly, MDA-MB435 and MCF7 cells viability followed a similar pattern. MDA-MB231 gene expression profile, as evaluated by cDNA microarray, was influenced by the fibroblasts presence, and HNMT, COMT, FN3K, and SOD2 were confirmed downregulated in MDA-MB231 co-cultured cells with fibroblasts from both negative and positive nodes, in a new series of RT-PCR assays. In summary, transcriptional changes induced in breast cancer cells by fibroblasts from positive as well as negative nodes are very much alike in a specific lineage. However, fibroblasts effects are distinct in each one of the breast cancer lineages, suggesting that the inter-relationships between stromal and malignant cells are dependent on the intrinsic subtype of the tumor.

Gene expression profile associated with response to doxorubicin-based therapy in breast cancer.

PURPOSE: This study was designed to identify genes that could predict response to doxorubicin-based primary chemotherapy in breast cancer patients. EXPERIMENTAL DESIGN: Biopsy samples were obtained before primary treatment with doxorubicin and cyclophosphamide. RNA was extracted and amplified and gene expression was analyzed using cDNA microarrays. RESULTS: Response to chemotherapy was evaluated in 51 patients, and based on Response Evaluation Criteria in Solid Tumors guidelines, 42 patients, who presented at least a partial response (> or =30% reduction in tumor dimension), were classified as responsive. Gene profile of samples, divided into training set (n = 38) and independent validation set (n = 13), were at first analyzed against a cDNA microarray platform containing 692 genes. Unsupervised clustering could not separate responders from nonresponders. A classifier was identified comprising EMILIN1, FAM14B, and PBEF, which however could not correctly classify samples included in the validation set. Our next step was to analyze gene profile in a more comprehensive cDNA microarray platform, containing 4,608 open reading frame expressed sequence tags. Seven samples of the initial training set (all responder patients) could not be analyzed. Unsupervised clustering could correctly group all the resistant samples as well as at least 85% of the sensitive samples. Additionally, a classifier, including PRSS11, MTSS1, and CLPTM1, could correctly distinguish 95.4% of the 44 samples analyzed, with only two misclassifications, one sensitive sample and one resistant tumor. The robustness of this classifier is 2.5 greater than the first one. CONCLUSION: A trio of genes might potentially distinguish doxorubicin-responsive from nonresponsive tumors, but further validation by a larger number of samples is still needed.

Correlação entre o polimorfismo do códoo 72 do gene p53 e a presença de DNA de papilomavírus humano (HPV) em carcinoma de pênis / Correlation between the polymorphism of chromium 72 of the p53 gene and the presence of human papillomavirus (HPV) DNA in penile carcinoma

O papilomavírus humano está fortemente associado ao desenvolvimento de neoplasias ano genitais. As oncoproteínas E6 e E7 dos HPV s de alto risco têm um papel importante na transformação celular. A proteína E6 forma um complexo com a p53, levando esta proteína à degradação através do mecanismo proteolitico dependente de ubiquitina. O gene p53 possui um polimorfismo no códon 72 do exon 4, que apresenta as variantes alélicas: arginina (p53Arg) e prolina (p53Pro ). As freqüências destes alelos se distribuem de forma diferente entre os grupos étnicos, assim como nos diferentes tipos de tumores observados. Recentemente, sugeriu-se que a variante arginina é mais susceptível à degradação pela interação da proteína E6 de HPV; além disto verificou-se que indivíduos homozigotos para arginina (p53Arg/ Arg) têm maior risco de desenvolver lesões malignas de colo de útero e cutâneas associadas ao HPV. Com base nesses resultados, objetivamos determinar o possível envolvimento deste polimorfismo como fator de nsco para o desenvolvimento de neoplasia de pênis, em casos positivos e negativos para a presença de DNA de HPV no tecido tumoral. Nossos resultados mostraram que entre os 65 casos de câncer de pênis e 247 amostras controles, os indivíduos heterozigotos foram mais freqüentes nos casos do que nos controles (OR, 1,8; 95 % CI, 1,05-3,16; P = 0,03), além de risco de 2,3 vezes maior de ser portador de câncer de pênis no grupo branco (95 %, 1,21-5, 12; P = 0,0 12). Além disso, o ale lo p53Pro apresentou um risco aumentado de 3 vezes para o mesmo grupo, enquanto que o alelo p53Arg sugere um risco positivo no grupo negro ou mulato, mas este resultado não mostrou diferença significativa. Entretanto, nenhuma evidência de correlação entre a presença de HPV e o polimorfismo do códon 72 do gene p53 no câncer de pênis foi observada neste estudo, mas observou-se uma associação positiva entre os portadores do alelo p53Arg de apresentarem tumores HPV negativos para qualquer grupo étnico. Isto poderia indicar que, os carcinomas de pênis HPV positivos e negativos se originariam através de mecanismos diferentes.

The human papillomaviruses (HPV) are associated with cervical cancer and another anogenital cancers. The E6 and E7 oncoproteins ofhigh-risk HPV types have the important role in cellular transformation. The E6 protein binds to as cellular tumor-suppressor protein p53 and directs its degradation through the ubiquitin pathway. The p53 gene has a common polymorphism at codon 72 of exon 4, encoding either variants arginine (p53Arg) o r proline (p52Pro ). Frequencies o fallelic variants of p53 differ widely depending on tumor type and ethnical group of the subjects under study. Recently, it has been suggested that individuais homozygous for p53Arg at codon 72 ofthe p53 gene are about 7 times more susceptible to HPVrelated carcinogenesis than heterozygotes. Based on these fmdings, we investigated the possible correlation between this polymorphism and risk of penile cancer associated with HPV infection from 65 cases and 247 controls. Our results show that the heterozygotes were more frequent among cases than controls (OR 1.8; 95 % CI 1.05-3.16; p=0.03) and they were 2.3 times more associated with cancer in the Caucasian group (95% CI 1.21 -5.12; p=O.Ol2). Moreover, the allele p53Pro shovved a 3-fold increase in risk in the same group, while p53Arg was positively associated among Blacks and Mulattos. This difference, however, did not reach statistical significance. No evidence of correlation between p53 polymorphism on codon 72 and penile cancer was found in relation to HPV infection in our population sample, but a positive association with p53Arg was observed in patients with HPV-negative cancers, in both ethnic groups. These results suggest that different mechanisms may be involved in the genesis o f penile cancers according to their HPV status.