Project description:Bilateral retinoblastoma has served as a critical model for studying genetic predisposition to cancer, however international incidence of unilateral retinoblastoma is variable across populations suggesting the involvement of environmental factors. DNA from Human Papilloma Virus (HPV) has been found in human retinoblastoma tissue through polymerase chain reaction based methods in several independent reports. To search for HPV oncoproteins and characterize transcriptional profiles in retinoblastoma, we analyzed tumor tissue obtained after enucleation and cultured for one week from 13 previously untreated Mexican children with retinoblastoma. We identified the presence of E7 HPV oncoproteins using western blot analysis in HPV positive tumors, and using non-supervised methods of classification on gene expression microarrays data, tumors clustered according to the presence or absence of HPV DNA identified by PCR. These methods were unable to discriminate retinoblastoma tissues by laterality. 2,404 genes were differentially expressed between HPV positive and HPV negative retinoblastoma, including a group of genes involved in a transcriptional response to viral infection. This molecular evidence supports the hypothesis that HPV is involved in the molecular pathogenesis of these tumors.
Project description:Since the role of wild rodents/small mammals in hepatitis E virus (HEV) epidemiology has been a subject of considerable debate, this study was conducted to investigate the potential presence of HEV RNA in small rodents collected within their natural habitats and to detect if they can be potential reservoirs of the virus. A total of 483 small rodents were captured using snap traps placed at 11 regions in Croatia. Sampling was undertaken in 2008 and repeated from 2010 to 2014. Liver samples were tested for the presence of HEV RNA. HEV RNA was detected in only one liver sample (0.21%) originated from Apodemus flavicollis from the location Medvednica, nearby Zagreb collected in 2014. According to the sequence analysis, the isolate has shown to be a member of Orthohepevirus A species, genotype HEV-3. The genotyping results confirmed grouping into subtype 3a, general cluster 3abchij.The detected HEV strain showed to be genetically highly related to strains found in humans and/or domestic pigs and wild boars from Croatia. Our finding indicates that wild small mammals could play a role in the epidemiology of HEV-3 infection and therefore should be taken under consideration as potential reservoirs or/and transmitters of the disease. However, further investigation is needed to recognize their potential for maintaining the infection in natural conditions.
Project description:Bilateral retinoblastoma has served as a critical model for studying genetic predisposition to cancer, however international incidence of unilateral retinoblastoma is variable across populations suggesting the involvement of environmental factors. DNA from Human Papilloma Virus (HPV) has been found in human retinoblastoma tissue through polymerase chain reaction based methods in several independent reports. To search for HPV oncoproteins and characterize transcriptional profiles in retinoblastoma, we analyzed tumor tissue obtained after enucleation and cultured for one week from 13 previously untreated Mexican children with retinoblastoma. We identified the presence of E7 HPV oncoproteins using western blot analysis in HPV positive tumors, and using non-supervised methods of classification on gene expression microarrays data, tumors clustered according to the presence or absence of HPV DNA identified by PCR. These methods were unable to discriminate retinoblastoma tissues by laterality. 2,404 genes were differentially expressed between HPV positive and HPV negative retinoblastoma, including a group of genes involved in a transcriptional response to viral infection. This molecular evidence supports the hypothesis that HPV is involved in the molecular pathogenesis of these tumors. The 13 children and tumors examined here, are incident cases participating in a larger case-control study at two Pediatric Hospitals of third level of medical attention in Mexico City, that form part of the public health system. Nine different tumors positive and four negative to HPV by PCR were included in the experimental design. From these, seven are unilateral and six are bilateral and are considered biological replicas. Two unilateral and two bilateral cases were chosen to make technical replicas. From the surgical specimens, two tumor portions were obtained, one was frozen, DNA was extracted from it, and HPV status was assigned using MY09 and MY11 primers by PCR. Another portion of tumor tissue was used to grow in culture, separating viable cells from non viable cells through a ficoll gradient. In the eye, retinoblastoma usually grows into the vitreous which has no cells, and thus the tissue obtained is predominantly formed by tumor cells and few endothelial cells from capillaries in the tumor. Retinoblastoma grow in culture as non adherent cells, and when adherent cells were also present, cell suspension was moved to a new dish to keep retinoblastoma cells as the main or only cellular type as possible. We used a two channel platform with in house spotted microarrays. Since retinoblastoma has known classes: uni and bilateral, we sought to verify these classes or discover new, we used a class discovery approach and a reference experimental design. As the reference sample we used RNA form exponentially growing Saccharomyces cerevisiae because major signaling pathways and basic cellular processes among Saccharomyces cerevisiae and mammalian cells including cell cycle control and DNA repair mechanisms have a high degree of conservation. Also because yeast is easy to grow, and thus a reliable and robust source of reference RNA.