Results 1 - 10 of 2552
Results 1 - 10 of 2552. Search took: 0.027 seconds
|Sort by: date | relevance|
[en] Highlights: • We characterized NGF variants predicted by FoldX protein design algorithm to have an altered binding to TrkA and p75NTR. • I31 was identified as a key residue within NGF that distinguishes between TrkA and p75NTR binding. • The I31R NGF selectively binds and activates p75NTR, while it did not exhibit the biological activity at TrkA receptor. Nerve growth factor (NGF) is the prototypic member of the neurotrophin family and binds two receptors, TrkA and the 75 kDa neurotrophin receptor (p75NTR), through which diverse and sometimes opposing effects are mediated. Using the FoldX protein design algorithm, we generated eight NGF variants with different point mutations predicted to have altered binding to TrkA or p75NTR. Of these, the I31R NGF variant exhibited specific binding to p75NTR. The generation of this NGF variant with selective affinity for p75NTR can be used to enhance understanding of neurotrophin receptor imbalance in diseases and identifies a key targetable residue for the development of small molecules to disrupt binding of NGF to TrkA with potential uses in chronic pain.
[en] Immunohistochemistry staining of p53 is a cheap and simple method to detect aberrant function of p53. However, there are some discrepancies between the result of immunohistochemistry staining and mutation analysis. This study attempted to find a new definition of p53 staining by its staining pattern. Immunohistochemistry staining of p53 and TP53 gene mutation analysis were performed in 148 gastric cancer patients. Also SNP-CGH array analysis was conducted to four cases. Positive staining of p53 was observed in 88 (59.5%) tumors. Tumors with positive p53 staining showed malignant features compared to negative tumors. Mutation of TP53 gene was observed in 29 (19.6%) tumors with higher age and differentiated type. In positive p53 tumors, two types could be distinguished; aberrant type and scattered type. With comparison to TP53 gene mutation analysis, all the scattered type had wild-type TP53 gene (P = 0.0003). SNP-CGH array showed that scattered-type tumors had no change in the structure of chromosome 17. P53-scattered-type staining tumors may reflect a functionally active nonmutated TP53 gene. In interpretation of p53 immunohistochemistry staining, distinguishing p53-positive tumors by their staining pattern may be important in gastric cancer
[en] Lung cancer is the leading cause of cancer deaths, with an overall survival of 15% at five years. Biomarkers that can sensitively and specifically detect lung cancer at early stage are crucial for improving this poor survival rate. Sputum has been the target for the discovery of non-invasive biomarkers for lung cancer because it contains airway epithelial cells, and molecular alterations identified in sputum are most likely to reflect tumor-associated changes or field cancerization caused by smoking in the lung. Sputum-based molecular biomarkers include morphology, allelic imbalance, promoter hypermethylation, gene mutations and, recently, differential miRNA expression. To improve the sensitivity and reproducibility of sputum-based biomarkers, we recommend standardization of processing protocols, bronchial epithelial cell enrichment, and identification of field cancerization biomarkers
[en] The mutations of the TP 53 and MTS1 (p16) gene have been described in numerous neoplasms but their relation with a response to the treatment is still little described. The aim of this work was to evaluate the value of the p53 status(serology, immunohistochemistry and molecular biology) and of the MTS1 gene( protein p16) for the response to the pre surgery radio chemotherapy in a troop of patients suffering from esophagus epidermoid cancer. The p53 serology is positive in 40% of cases and is statistically associated to a bad response. The lost of alleles for MTS1 has been found in 20% of cases but non predictive to the response. A prospective study would be interesting. (N.C.)
[en] A phylogenetic analysis of family Solanaceae was conducted using sequence data from the chloroplast intergenic atp beta-rbcL spacer. Sequence data was generated from 17 species representing 09 out of 14 genera of Solanaceae from Pakistan. Cladogram was constructed using maximum parsimony method and results indicate that Solanaceae is mainly divided into two subfamilies; Solanoideae and Cestroideae. Four major clades within Solanoideae represent tribes; Physaleae, Capsiceae, Datureae and Solaneae are supported by high bootstrap value and the relationships among them are not corroborating with the previous studies. The findings established that subfamily Cestroideae comprised of three genera; Cestrum, Lycium and Nicotiana with high bootstrap support. Position of Nicotiana inferred with atp beta-rbcL sequence is congruent with traditional classification, which placed the taxa in Cestroideae. In the current study Lycium unexpectedly nested with Nicotiana with 100% bootstrap support and identified as a member of tribe Nicotianeae. Expanded sampling of other genera from Pakistan could be valuable towards improving our understanding of intrafamilial relationships within Solanaceae. (author)
[en] We identified a bifunctional regulatory element located between nt 374 and 431 upstream of TATA box of porcine adenovirus (PAV) 3 E1A promoter. Deletion of the element dramatically reduced the steady-state level of E1A mRNA, but increased that of E1B, which lies immediately downstream of E1A. The mutant virus displayed defective replication at early times of infection, but replicated nearly as efficiently as wild-type PAV-3 at late times of infection. This defect was complemented with coinfecting wild-type virus in a mixed infection. The results indicated that the upstream activation sequences (UAS) of E1A overlap the upstream repression sequences (URS) of E1B, although both transcription units are transcribed from different promoters
[en] Isocitrate dehydrogenase 1 and 2 (IDH1 and IDH2) are key metabolic enzymes that convert isocitrate to α-ketoglutarate. Somatic point mutations in IDH1/2 confer a gain-of-function in cancer cells, resulting in overproduction of an oncometabolite, 2-hydroxyglutarate (2HG). 2HG interferes with cellular metabolism and epigenetic regulation, contributing to oncogenesis. Given that IDH1 and IDH2 are attracting attention as promising therapeutic targets, better evaluation of the incidence of IDH1 and IDH2 mutations and 2HG level in human cancers is clinically important. This is the first study to assess their incidence in esophageal squamous cell carcinomas (ESCCs). First, we established pyrosequencing assays for IDH1 and IDH2 mutations and revealed that these mutations were absent in 10 ESCC cell lines and 96 ESCC tissues. Second, utilizing IDH1 and IDH2 overexpression vectors, we demonstrated that LC-MS/MS assays can accurately evaluate 2HG level and found that some ESCC cases presented a high level of 2HG. In conclusion, IDH1 or IDH2 mutations play a limited role in the development of ESCC. 2HG is potentially synthesized to high levels in the absence of IDH1 and IDH2 mutations, and this may correlate with progression of ESCCs.
[en] Highlights: • The CCN3 thrombospondin type-1 (TSP1) domain is required for its secretion. • The TSP1 domain is also involved in CNN3 intracellular function. • Residue C241 is important for CNN3 secretion, but not its intracellular function. • Palmitoylation at C241 is necessary for CCN3 secretion. • Zinc finger DHHC-type containing 22 interacts with CCN3. Normal extracellular secretion of nephroblastoma overexpressed (NOV, also known as CCN3) is important for the adhesion, migration, and differentiation of cells. In previous studies, we have shown that the intracellular accumulation of CCN3 inhibits the growth of prominent neurons. Increased intracellular CCN3 can be induced through various processes, such as transcription, detoxification, and posttranslational modification. In general, posttranslational modifications are very important for protein secretion. However, it is unclear whether posttranslational modification is necessary for CCN3 secretion. In this study, we have conducted mutational analysis of CCN3 to demonstrate that its thrombospondin type-1 (TSP1) domain is important for CCN3 secretion and intracellular function. Point mutation analysis confirmed that CCN3 secretion was inhibited by cysteine (C)241 mutation, and overexpression of CCN3-C241A inhibited neuronal axonal growth in vivo. Furthermore, we demonstrated that palmitoylation is important for the extracellular secretion of CCN3 and that zinc finger DHHC-type containing 22 (ZDHHC22), a palmityoltransferase, can interact with CCN3. Taken together, our results suggest that palmitoylation by ZDHHC22 at C241 in the CCN3 TSP1 domain may be required for the secretion of CCN3. Aberrant palmitoylation induces intracellular accumulation of CCN3, inhibiting neuronal axon growth.
[en] Mutations in genes that are part of the splicing machinery for myelodysplastic syndromes (MDS), including MDS without ring sideroblasts (RS), have been widely investigated. The effects of these mutations on clinical outcomes have been diverse and contrasting. We examined a cohort of 129 de novo MDS patients, who did not harbor RS, for mutations affecting three spliceosomal genes (SF3B1, U2AF1, and SRSF2). The mutation rates of SF3B1, U2AF1, and SRSF2 were 7.0 %, 7.8 %, and 10.1 %, respectively. Compared with previously reported results, these rates were relatively infrequent. The SRSF2 mutation strongly correlated with old age (P < 0.001), while the mutation status of SF3B1 did not affect overall survival (OS), progression-free survival (PFS), or acute myeloid leukemia (AML) transformation. In contrast, MDS patients with mutations in U2AF1 or SRSF2 exhibited inferior PFS. The U2AF1 mutation was associated with inferior OS in low-risk MDS patients (P = 0.035). The SRSF2 mutation was somewhat associated with AML transformation (P = 0.083). Our findings suggest that the frequencies of the SF3B1, U2AF1, and SRSF2 splicing gene mutations in MDS without RS were relatively low. We also demonstrated that the U2AF1 and SRSF2 mutations were associated with an unfavorable prognostic impact in MDS patients without RS. The online version of this article (doi:10.1186/s12885-015-1493-5) contains supplementary material, which is available to authorized users
[en] Knowledge about tumour gene mutation status is essential for the treatment of increasing numbers of cancer patients, and testing quality has a major impact on treatment response and cost. In 2012, 4,629 tests for BRAF p.V600 were performed in France, in patients with melanomas. Two batches of unstained melanoma sections were sent, in May and November 2012, to the 46 laboratories supported by the French National Institute of Cancer (INCa). An external quality assessment (EQA) evaluated mutation status, response times and compliance with INCa recommendations. All the French laboratories involved in testing participated in the EQA. Fourteen different methods were used to detect BRAF mutations, most consisting of combinations of in-house techniques. False responses were noted in 25/520 cases (4.8%), 11 of which concerned confusion between p.V600E and p.V600K. Thus, 2.7% of responses would have led to inappropriate treatment. Within six months, mean response times decreased from 22 to 12 days (P<0.001), and the percentage of samples evaluated by a pathologist for tumour cell content increased, from 75.2% to 96.9% (P<0.001). Despite the use of non-certified methods, the false response rate was low. Nationwide EQA can improve the quality of molecular pathology tests on tumours