Reference gene selection for head and neck squamous cell carcinoma gene expression studies

<p>Abstract</p> <p>Background</p> <p>It is no longer adequate to choose reference genes blindly. We present the first study that defines the suitability of 12 reference genes commonly used in cancer studies (<it>ACT, ALAS, B2M, GAPDH, HMBS, HPRT, KALPHA, RPS18, RPL27, RPS29, SHAD </it>and <it>TBP</it>) for the normalization of quantitative expression data in the field of head and neck squamous cell carcinoma (HNSCC).</p> <p>Results</p> <p>Raw expression levels were measured by RT-qPCR in HNSCC and normal matched mucosa of 46 patients. We analyzed the expression stability using geNorm and NormFinder and compared the expression levels between subgroups. In HNSCC and/or normal mucosa, the four best normalization genes were <it>ALAS, GAPDH, RPS18 </it>and <it>SHAD </it>and the most stable combination of two genes was <it>GAPDH-SHAD</it>. We recommend using <it>KALPHA-TBP </it>for the study of T1-T2 tumors, <it>RPL27-SHAD </it>for T3-T4 tumors, <it>KALPHA-SHAD </it>for N0 tumors, and <it>ALAS-TBP </it>for N+ tumors. <it>ACT, B2M, GAPDH, HMBS, HPRT, KALPHA, RPS18, RPS29, SHAD </it>and <it>TBP </it>were slightly misregulated (<1.7-fold) between tumor and normal mucosa but can be used for normalization, depending on the resolution required for the assay.</p> <p>Conclusion</p> <p>In the field of HNSCC, this study will guide researchers in selecting the most appropriate reference genes from among 12 potentially suitable reference genes, depending on the specific setting of their experiments.</p

Pregnane × Receptor (PXR) expression in colorectal cancer cells restricts irinotecan chemosensitivity through enhanced SN-38 glucuronidation

<p>Abstract</p> <p>Background</p> <p>Clinical efficacy of chemotherapy in colorectal cancer is subjected to broad inter-individual variations leading to the inability to predict outcome and toxicity. The topoisomerase I inhibitor irinotecan (CPT-11) is worldwide approved for the treatment of metastatic colorectal cancer and undergoes extensive peripheral and tumoral metabolism. PXR is a xenoreceptor activated by many drugs and environmental compounds regulating the expression of drug metabolism and transport genes in detoxification organs such as liver and gastrointestinal tract. Considering the metabolic pathway of irinotecan and the tissue distribution of Pregnane × Receptor (PXR), we hypothesized that PXR could play a key role in colon cancer cell response to irinotecan.</p> <p>Results</p> <p>PXR mRNA expression was quantified by RT-quantitative PCR in a panel of 14 colon tumor samples and their matched normal tissues. PXR expression was modulated in human colorectal cancer cells LS174T, SW480 and SW620 by transfection and siRNA strategies. Cellular response to irinotecan and its active metabolic SN38 was assessed by cell viability assays, HPLC metabolic profiles and mRNA quantification of PXR target genes. We showed that PXR was strongly expressed in colon tumor samples and displayed a great variability of expression. Expression of hPXR in human colorectal cancer cells led to a marked chemoresistance to the active metabolite SN38 correlated with PXR expression level. Metabolic profiles of SN38 showed a strong enhancement of SN38 glucuronidation to the inactive SN38G metabolite in PXR-expressing cells, correlated with an increase of UDPglucuronosyl transferases UGT1A1, UGT1A9 and UGT1A10 mRNAs. Inhibition of PXR expression by lentivirus-mediated shRNA, led to SN38 chemoresistance reversion concomitantly to a decrease of UGT1A1 expression and SN38 glucuronidation. Similarly, PXR mRNA expression levels correlated to UGT1A subfamily expression in human colon tumor biopsies.</p> <p>Conclusion</p> <p>Our results demonstrate that tumoral metabolism of SN38 is affected by PXR and point to potential therapeutic significance of PXR quantification in the prediction of irinotecan response. Furthermore, our observations are pharmacologically relevant since many patients suffering from cancer diseases are often exposed to co-medications, food additives or herbal supplements able to activate PXR. A substantial part of the variability observed among patients might be caused by such interactions</p

A common polymorphism in NR1H2 (LXRbeta) is associated with preeclampsia

<p>Abstract</p> <p>Background</p> <p>Preeclampsia is a frequent complication of pregnancy and a leading cause of perinatal mortality. Both genetic and environmental risk factors have been identified. Lipid metabolism, particularly cholesterol metabolism, is associated with this disease. Liver X receptors alpha (NR1H3, also known as LXRalpha) and beta (NR1H2, also known as LXRbeta) play a key role in lipid metabolism. They belong to the nuclear receptor superfamily and are activated by cholesterol derivatives. They have been implicated in preeclampsia because they modulate trophoblast invasion and regulate the expression of the endoglin (CD105) gene, a marker of preeclampsia. The aim of this study was to investigate associations between the <it>NR1H3 </it>and <it>NR1H2 </it>genes and preeclampsia.</p> <p>Methods</p> <p>We assessed associations between single nucleotide polymorphisms of <it>NR1H3 </it>(rs2279238 and rs7120118) and <it>NR1H2 </it>(rs35463555 and rs2695121) and the disease in 155 individuals with preeclampsia and 305 controls. Genotypes were determined by high-resolution melting analysis. We then used a logistic regression model to analyze the different alleles and genotypes for those polymorphisms as a function of case/control status.</p> <p>Results</p> <p>We found no association between <it>NR1H3 </it>SNPs and the disease, but the <it>NR1H2 </it>polymorphism rs2695121 was found to be strongly associated with preeclampsia (genotype C/C: adjusted odds ratio, 2.05; 95% CI, 1.04-4.05; <it>p </it>= 0.039 and genotype T/C: adjusted odds ratio, 1.85; 95% CI, 1.01-3.42; <it>p </it>= 0.049).</p> <p>Conclusions</p> <p>This study provides the first evidence of an association between the <it>NR1H2 </it>gene and preeclampsia, adding to our understanding of the links between cholesterol metabolism and this disease.</p

Clinical relevance of nine transcriptional molecular markers for the diagnosis of head and neck squamous cell carcinoma in tissue and saliva rinse

<p>Abstract</p> <p>Background</p> <p>Analysis of 23 published transcriptome studies allowed us to identify nine genes displaying frequent alterations in HNSCC (<it>FN1, MMP1, PLAU, SPARC</it>, <it>IL1RN, KRT4, KRT13, MAL</it>, and <it>TGM3</it>). We aimed to independently confirm these dysregulations and to identify potential relationships with clinical data for diagnostic, staging and prognostic purposes either at the tissue level or in saliva rinse.</p> <p>Methods</p> <p>For a period of two years, we systematically collected tumor tissue, normal matched mucosa and saliva of patients diagnosed with primary untreated HNSCC. Expression levels of the nine genes of interest were measured by RT-qPCR in tumor and healthy matched mucosa from 46 patients. <it>MMP1 </it>expression level was measured by RT-qPCR in the salivary rinse of 51 HNSCC patients and 18 control cases.</p> <p>Results</p> <p>Dysregulation of the nine genes was confirmed by the Wilcoxon test. <it>IL1RN, MAL </it>and <it>MMP1 </it>were the most efficient diagnostic markers of HNSCC, with ROC AUC > 0.95 and both sensitivity and specificity above 91%. No clinically relevant correlation was found between gene expression level in tumor and T stage, N stage, tumor grade, global survival or disease-free survival. Our preliminary results suggests that with 100% specificity, <it>MMP1 </it>detection in saliva rinse is potentially useful for non invasive diagnosis of HNSCC of the oral cavity or oropharynx, but technical improvement is needed since sensitivity was only 20%.</p> <p>Conclusion</p> <p><it>IL1RN, MAL </it>and <it>MMP1 </it>are prospective tumor diagnostic markers for HNSCC. <it>MMP1 </it>overexpression is the most promising marker, and its detection could help identify tumor cells in tissue or saliva.</p

Meta-analysis of SHANK Mutations in Autism Spectrum Disorders: A Gradient of Severity in Cognitive Impairments.

International audienceSHANK genes code for scaffold proteins located at the post-synaptic density of glutamatergic synapses. In neurons, SHANK2 and SHANK3 have a positive effect on the induction and maturation of dendritic spines, whereas SHANK1 induces the enlargement of spine heads. Mutations in SHANK genes have been associated with autism spectrum disorders (ASD), but their prevalence and clinical relevance remain to be determined. Here, we performed a new screen and a meta-analysis of SHANK copy-number and coding-sequence variants in ASD. Copy-number variants were analyzed in 5,657 patients and 19,163 controls, coding-sequence variants were ascertained in 760 to 2,147 patients and 492 to 1,090 controls (depending on the gene), and, individuals carrying de novo or truncating SHANK mutations underwent an extensive clinical investigation. Copy-number variants and truncating mutations in SHANK genes were present in ∼1% of patients with ASD: mutations in SHANK1 were rare (0.04%) and present in males with normal IQ and autism; mutations in SHANK2 were present in 0.17% of patients with ASD and mild intellectual disability; mutations in SHANK3 were present in 0.69% of patients with ASD and up to 2.12% of the cases with moderate to profound intellectual disability. In summary, mutations of the SHANK genes were detected in the whole spectrum of autism with a gradient of severity in cognitive impairment. Given the rare frequency of SHANK1 and SHANK2 deleterious mutations, the clinical relevance of these genes remains to be ascertained. In contrast, the frequency and the penetrance of SHANK3 mutations in individuals with ASD and intellectual disability-more than 1 in 50-warrant its consideration for mutation screening in clinical practice

Utilisation des organostanniques pour la synthèse stéréocontrôlée d'iminosucres

NANTES-BU Sciences (441092104) / SudocSudocFranceF

Enantioselective Synthesis of Branched Allylic Esters via Rhodium-Catalyzed Coupling of Allenes with Carboxylic Acids

We report on the first intermolecular asymmetric catalytic regio- and enantioselective addition of carboxylic acids to terminal allenes to form valuable branched allylic esters, employing a rhodium­(I)/(<i>R,R</i>)-DIOP catalyst system

Stereodivergent synthesis of iminosugars from stannylated derivatives of (S)-vinylglycinol.

International audienceAn original access to iminosugars from a cis/trans mixture of stannylated oxazolidinones 5 is reported. The dehydropiperidines 7-trans and 7-cis were obtained stereoselectively with an RS and SS configuration depending on the order of the Sn-Li transmetalation (followed by electrophilic trapping) and of the ring closing metathesis reactions due to the stereoselective epimerization of the α-aminoanion intermediate. The dehydropiperidines 7-trans and 7-cis were subsequently used for the synthesis of enantiopure homonojirimycin analogs

An efficient and scalable synthesis of N-(benzyloxycarbonyl)- and N-(methyloxycarbonyl)-(S)-vinylglycinol

International audienc

Microwave-assisted synthesis of alpha-ethoxycarbamates

International audienc