88 research outputs found
TGFBR1 variants TGFBR1*6A and Int7G24A are not associated with an increased familial colorectal cancer risk
Variants of the transforming growth factor-beta receptor type 1 (TGFBR1) gene, TGFBR1*6A and Int7G24A, have been suggested to act as low-penetrance tumour susceptibility alleles with TGFBR1*6A being causally responsible for some cases of familial colorectal cancer (CRC). We performed a case–control study of 262 unrelated familial CRC cases; 83 hereditary non-polyposis colorectal cancer (HNPCC) and 179 non-HNPCC. Patients were genotyped for TGFBR1*6A and Int7G24A and compared with 856 controls. Further, we screened the coding region of TGFBR1 in affected members of a large family with CRC linked to 9q22.32-31.1. TGFBR1*6A allelic frequency was not significantly different in all of the familial cases compared with controls (0.107 and 0.106, respectively; P=0.915). In a subgroup analysis allele frequencies were, however, different between HNPCC and non-HNPCC familial cases (0.157 and 0.084, respectively; P=0.013). TGFBR1*6A genotype did not influence age of onset. Int7G24A allele frequencies were similar in cases and controls. No germ-line mutation was identified in the family with CRC linked to this chromosomal region. Our study provides no substantial support for the hypothesis that the polymorphic variants TGFBR1*6A or Int7G24A contribute to familial CRC risk. We cannot, however, exclude the possibility that TGFBR1 variants have a modifying effect on inherited risk per se
Analysis of the Mitogen-activated protein kinase kinase 4 (MAP2K4) tumor suppressor gene in ovarian cancer
<p>Abstract</p> <p>Background</p> <p><it>MAP2K4 </it>is a putative tumor and metastasis suppressor gene frequently found to be deleted in various cancer types. We aimed to conduct a comprehensive analysis of this gene to assess its involvement in ovarian cancer.</p> <p>Methods</p> <p>We screened for mutations in <it>MAP2K4 </it>using High Resolution Melt analysis of 149 primary ovarian tumors and methylation at the promoter using Methylation-Specific Single-Stranded Conformation Polymorphism analysis of 39 tumors. We also considered the clinical impact of changes in <it>MAP2K4 </it>using publicly available expression and copy number array data. Finally, we used siRNA to measure the effect of reducing <it>MAP2K4 </it>expression in cell lines.</p> <p>Results</p> <p>In addition to 4 previously detected homozygous deletions, we identified a homozygous 16 bp truncating deletion and a heterozygous 4 bp deletion, each in one ovarian tumor. No promoter methylation was detected. The frequency of <it>MAP2K4 </it>homozygous inactivation was 5.6% overall, and 9.8% in high-grade serous cases. Hemizygous deletion of <it>MAP2K4 </it>was observed in 38% of samples. There were significant correlations of copy number and expression in three microarray data sets. There was a significant correlation between <it>MAP2K4 </it>expression and overall survival in one expression array data set, but this was not confirmed in an independent set. Treatment of JAM and HOSE6.3 cell lines with <it>MAP2K4 </it>siRNA showed some reduction in proliferation.</p> <p>Conclusions</p> <p><it>MAP2K4 </it>is targeted by genetic inactivation in ovarian cancer and restricted to high grade serous and endometrioid carcinomas in our cohort.</p
Resveratrol increases BRCA1 and BRCA2 mRNA expression in breast tumour cell lines
International audienceThe phytochemical resveratrol, found in grapes, berries and peanuts, has been found to possess cancer chemopreventive effects by inhibiting diverse cellular events associated with tumour initiation, promotion and progression. Resveratrol is also a phyto-oestrogen, binds to and activates oestrogen receptors that regulate the transcription of oestrogen-responsive target genes such as the breast cancer susceptibility genes BRCA1 and BRCA2. We investigated the effects of resveratrol on BRCA1 and BRCA2 expression in human breast cancer cell lines (MCF7, HBL 100 and MDA-MB 231) using quantitative real-time RT-PCR, and by perfusion chromatography of the proteins. All cell lines were treated with 30 microM resveratrol. The expressions of BRCA1 and BRCA2 mRNAs were increased although no change in the expression of the proteins were found. These data indicate that resveratrol at 30 micro M can increase expression of genes involved in the aggressiveness of human breast tumour cell lines
Regulation of BRCA1 expression and its relationship to sporadic breast cancer
Germ-line mutations in the BRCA1 tumour suppressor gene contribute to familial breast tumour formation, but there is no evidence for direct mutation of the BRCA1 gene in the sporadic form of the disease. In contrast, decreased expression of the BRCA1 gene has been shown to be common in sporadic tumours, and the magnitude of the decrease correlates with disease progression. BRCA1 expression is also tightly regulated during normal breast development. Determining how these developmental regulators of BRCA1 expression are co-opted during breast tumourigenesis could lead to a better understanding of sporadic breast cancer aetiology and the generation of novel therapeutic strategies aimed at preventing sporadic breast tumour progression
Phenolic and furanic compounds of Portuguese chestnut and French, American and Portuguese oak wood chips
Botanical species used on aging process must
be wisely and judiciously chosen, and for this selection, a
basic knowledge of the chemical composition of woods is
warranted. Aiming to contribute to extend the knowledge
of the chemical composition of several wood species useful
for enological purposes, we have focused our studies on
Portuguese chestnut and French, American and Portuguese
oak chips. The profile of low molecular weight phenolic
composition of these chips was achieved, using an optimized
extraction method based on pressurized liquid
extraction, followed by the quantification of phenolic acids,
phenolic aldehydes and furanic derivatives by high-performance
liquid chromatography (HPLC-DAD). The
identification of those compounds was also confirmed by
LC-DAD/ESI-MS. This study allowed the determination of
the low molecular phenolic composition of Portuguese
chestnut and French, American and Portuguese oak wood.
According to our results, the influence of the botanical
species seems to be more relevant than the geographic
origin of the wood species
Genomes of cryptic chimpanzee Plasmodium species reveal key evolutionary events leading to human malaria
African apes harbour at least six Plasmodium species of the subgenus Laverania, one of which gave rise to human Plasmodium falciparum. Here we use a selective amplification strategy to sequence the genome of chimpanzee parasites classified as Plasmodium reichenowi and Plasmodium gaboni based on the subgenomic fragments. Genome-wide analyses show that these parasites indeed represent distinct species, with no evidence of cross-species mating. Both P. reichenowi and P. gaboni are 10-fold more diverse than P. falciparum, indicating a very recent origin of the human parasite. We also find a remarkable Laverania-specific expansion of a multigene family involved in erythrocyte remodelling, and show that a short region on chromosome 4, which encodes two essential invasion genes, was horizontally transferred into a recent P. falciparum ancestor. Our results validate the selective amplification strategy for characterizing cryptic pathogen species, and reveal evolutionary events that likely predisposed the precursor of P. falciparum to colonize humans
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