Molecular cloning and characterization of a putative OGG_N domain from the camel, Camelus dromedarius

Reactive oxygen species (ROS) oxidize the guanine base in the DNA to 8-oxoguanine (8-oxoG). This lesion, if left unrepaired, causes the transversion of G:C pair to T:A following replication. 8-oxoG is targeted by one of the DNA glycosylases, namely OGG1. Arabian camel (one humped camel, Camelus dromedarius) is adapted to live in desert climate conditions under direct exposure to endogenous and exogenous ROS-producing conditions, among of them the sunlight. In the recent study, partial sequence of camel OGG-1 gene was cloned and analyzed for the first time. A DNA fragment of 567 bases was amplified by reverse transcription PCR. It is equivalent to about 55% from the coding region of the known transcript of many organisms. The level of expression of OGG-1 in different camel tissues (liver, kidney, spleen, lung and testis) was examined using real time-PCR. The highest level of OGG-1 transcript was found in the camel liver (represented as 100%) followed by testis (85%), spleen (78%), kidney (37%) and lung (3%) using 18S ribosomal subunit as endogenous control. The obtained cDNA sequence of OGG-1 showed high similarity with Ailuropoda melanoleuca (86%), Sus scrofa (86%), Canis familiaris (85%), Bos taurus (85%), Macaca mulatta (85%), Homo sapiens (84%), Pan troglodytes (84%) and Pongo abelii (82%).Keywords: Camelus dromedarius, cloning, OGG1, gene expression, DNA glycosylas

Frequent Activation of Notch Signaling Pathway in Colorectal Cancers and Its Implication in Patient Survival Outcome

Colorectal cancer is a major health concern as it ranks third in incidence and second major cause of cancer-related deaths worldwide. A leading cause of treatment failure has been attributed to cancer stem cells that can invariably resist existing chemotherapeutic regimens. Notch signaling pathway has been involved in the maintenance of stem cells besides being crucial in cell fate decision and embryonic development. This pathway has also been implicated in several human malignancies including colorectal cancer. We investigated mRNA expression of four Notch receptors (Notch1–4), five ligands (Jag1, Jag2, Dll1, Dll3, and Dll4), and four target genes (Hes1, Hes5, Hey1, and Hey2) using highly specific TaqMan gene expression assays in colorectal adenomas and cancers. Upregulated expression of Notch receptors ranged between 29 and 73% in colorectal cancers and between 11 and 56% in adenomas. Expression of Notch3 and Notch4 receptors was significantly higher in colorectal cancers compared to normal and adenoma tissues. The Jagged and Delta-like ligands were overexpressed between 25 and 52% in colorectal cancers, while in adenomas, it ranged between 0 and 33%. Combining the data for upregulation of receptors and ligands suggests that 86% colorectal cancers and 56% adenomas exhibited overexpression of Notch pathway genes in our cohort. Notch target genes were upregulated between 24 and 33% in colorectal cancers and between 11 and 22% in adenomas. Collating upregulation of Notch receptors and ligands with the target genes showed concordance in 58% colorectal tumors. Additionally, we evaluated expression of Notch receptors, ligands, and target genes with prognosis using the TCGA mRNA expression dataset. Patients overexpressing Notch3, Notch4, and Hey1 had significantly poorer overall survival relative to those having lower levels of these genes. Taken together, Notch signaling components are aberrantly overexpressed in colorectal tumors, and development of therapeutics targeting the Notch pathway may prove to be beneficial in the management of colorectal cancers

Description of SNPs present in Wnt pathway genes that were analyzed.

*<p>Source – dbSNP, National Center for Biotechnology Information.</p

Comparison of genotype frequencies of SNPs in Wnt pathway genes between ER- breast cancers versus controls.

<p>BC. Breast Cancer; ER-. Estrogen Receptor negative; OR 95% CI. Odds Ratio and 95% Confidence Interval.</p>*<p>P<0.05 was considered significant and are depicted in bold.</p

Genotype frequencies of Wnt pathway gene polymorphism in breast cancers and Controls.

<p>BC. Breast Cancer; OR 95% CI. Odds Ratio and 95% Confidence Interval.</p>*<p>P<0.05 was considered significant and are depicted in bold.</p

Expression and Polymorphism of Toll-Like Receptor 4 and Effect on NF-κB Mediated Inflammation in Colon Cancer Patients

<div><p>Our aim was to evaluate the association between the expression and the polymorphism of TLR4/NF-κB pathways and colon cancer. TLR4 (<i>rs4986790</i>, <i>rs10759932</i>, <i>rs10759931</i> and <i>rs2770150</i>) were genotyped in blood samples from Colorectal patients and healthy controls. TLR4 and cytokines inflammatory expression were evaluated by real time PCR on 40 matching normal and colon tissues and the protein level by Immunohistochemistry. The high level of TLR4 expression in colon cancer tissues is mainly due to infections by bacteria in the human colon and leads to induction of an acute secretion of inflammatory cytokines mediated by NF-κB. Also, we report here a clear evidence for an association between TLR4 <i>rs10759931</i> polymorphism (OR = 0.086, CI: 0.04–0.18, P = <0.00001). This polymorphism affects the entire population without being specific to either gender or to any age group. In contrast, the <i>rs2770150</i> is associated with colon cancer in women aged over 50 years and is closely linked with the decreased levels of female sex hormones during the post-menopausal period (OR = 0.188, CI: 0.074–0.48, P = <0.00084). <i>rs10759932</i> and <i>rs4986790</i> appear to have any association with colon cancer. Our data suggest that TLR4 SNPs could possibly serve as biomarkers for decision making in colon cancer treatment.</p></div