Practice guidelines for the management of Helicobacter pylori infection: The Saudi H. pylori Working Group recommendations

The eradication rates for Helicobacter pylori globally are decreasing with a dramatic increase in the prevalence of antibiotic resistant bacteria all over the world, including Saudi Arabia. There is no current consensus on the management of H. pylori in Saudi Arabia. The Saudi Gastroenterology Association developed these practice guidelines after reviewing the local and regional studies on the management of H. pylori. The aim was to establish recommendations to guide healthcare providers in managing H. pylori in Saudi Arabia. Experts in the areas of H. pylori management and microbiology were invited to write these guidelines. A literature search was performed, and all authors participated in writing and reviewing the guidelines. In addition, international guidelines and consensus reports were reviewed to bridge the gap in knowledge when local and regional data were unavailable. There is limited local data on treatment of H. pylori. The rate of clarithromycin and metronidazole resistance is high; therefore, standard triple therapy for 10–14 days is no longer recommended in the treatment of H. pylori unless antimicrobial susceptibility testing was performed. Based on the available data, bismuth quadruple therapy for 10–14 days is considered the best first-line and second-line therapy. Culture and antimicrobial susceptibility testing should be considered following two treatment failures. These recommendations are intended to provide the most relevant evidence-based guidelines for the management of H. pylori infection in Saudi Arabia. The working group recommends further studies to explore more therapeutic options to eradicate H. pylori

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

Expression and Polymorphism of TSLP/TSLP Receptors as Potential Diagnostic Markers of Colorectal Cancer Progression

Colorectal cancer (CRC) is the third most common malignancy and the fourth leading cause of cancer-related mortality worldwide. Inflammation is considered as a critical driver for CRC development and growth. We investigated the association between polymorphisms/expression levels of thymic stromal lymphopoietin (TSLP) /TSLP receptors and CRC risk in Saudi population. DNA samples were isolated from blood samples from 220 participants. Case subjects were 112 patients diagnosed with CRC, while control subjects were 108 healthy individuals, who were not diagnosed with any type of malignancy. We selected two single nucleotide polymorphisms (SNPs) located in the thymic stromal lymphopoietin gene (rs10043985 and rs2289276), three SNPs in TSLP receptor gene (TSLPR; rs36139698, rs36177645, and rs36133495), and two other SNPs in interleukin-7 receptor gene (IL-7R; rs12516866 and rs1053496), and designated these SNPs for a case-control genotyping study. The gene expression was analyzed using quantitative RT-PCR and immunohistochemistry assays array on 20 matching colorectal cancer/normal tissues. mRNA expressions and protein levels of TSLP, TSLPR-α subunit, and IL-7R-α subunit showed a 4-fold increase in colon cancer tissues when compared to normal colon tissues. Furthermore, two SNPs (rs10043985 of TSLP and rs1053496 of IL-7R) showed statistically significant correlations with CRC susceptibility. Interestingly, only rs10043985 showed a statistically significant association (p < 0.0001) in the genotypic and phenotypic levels with CRC for all clinical parameters (age, gender, and tumor location) tested. However, IL-7R rs1053496 genotyping results presented a significant correlation (p < 0.05) in male CRC patients and in individuals under 57 years of age. TSLP rs2289276, IL-7R rs12516866, and all TSLPR variants did not display any significant genotypic or phenotypic correlations in all tested clinical parameters. This study identified that TSLP rs10043985 and IL-7R rs1053496 SNPs, and the expression levels of TSLP and TSLPR-α subunit, can be used as markers for CRC development and treatment. However, additional investigations are required on larger group of patients from diverse ethnicities to confirm the genetic association of these variants to CRC

The expression of telomere-related proteins and DNA damage response and their association with telomere length in colorectal cancer in Saudi patients.

BACKGROUND:Colorectal cancer is the leading cause of cancer-related deaths in Saudi Arabia. Cancer has a multifactorial nature and can be described as a disease of altered gene expression. The profiling of gene expression has been used to identify cancer subtypes and to predict patients' responsiveness. Telomere-associated proteins that regulate telomere biology are essential molecules in cancer development. Thus, the present study examined their contributions to colorectal cancer progression in Saudi patients. METHODS:The expression of hTERT, TRF1, TRF2, POT1, ATR, ATM, Chk1 and Chk2 were measured via real-time PCR in matched cancerous and adjacent tissues of CRC patients. The protein level of hTERT, TRF1, TRF2, ATR, ATM, Chk1 and Chk2 were measured using immunohistochemistry. A region of hTERT core promoter was sequenced via Sanger sequencing. Methylation of CTCF binding site was examined via methylation-specific PCR. Finally, the length of telomere was estimated using q-PCR. RESULTS:Our results showed that POT1, ATR, Chk1 and Chk2 show increased expression in CRC relative to the adjacent mucosa. The expression levels of each gene were associated with clinicopathological characteristics of patients with CRC. There was a positive correlation between the age of the patients and hTERT expression. Regarding tumor site, telomere length, ATR, ATM and Chk1 were shown to be altered. No somatic mutation was detected in hTERT core promoter, and no differences in methylation patterns at CTCF binding site in the promoter between normal and cancer tissues. CONCLUSION:Analysis of targeted genes expression in colorectal cancer based on the clinical variables revealed that tumor location and age could have a role in gene expression and telomere length variations and this could be taken under consideration during CRC diagnosis and therapy. Other epigenetic mechanisms could influence hTERT expression in cancers. Our findings warrant further validation through experiments involving a larger number of patients

Expression and new exon mutations of the human Beta defensins and their association on colon cancer development.

The development of cancer involves genetic predisposition and a variety of environmental exposures. Genome-wide linkage analyses provide evidence for the significant linkage of many diseases to susceptibility loci on chromosome 8p23, the location of the human defensin gene cluster. Human β-defensins (hBDs) are important molecules of innate immunity. This study was designed to analyze the expression and genetic variations in hBDs (hBD-1, hBD-2, hBD-3 and hBD-4) and their putative association with colon cancer. hBD gene expression and relative protein expression were evaluated by Real-Time polymerase chain reaction (qPCR) and immunohistochemistry, respectively, from 40 normal patients and 40 age-matched patients with colon cancer in Saudi Arabia. In addition, hBD polymorphisms were genotyped by exon sequencing and by promoter methylation. hBD-1, hBD-2, hBD-3 and hBD-4 basal messenger RNA expression was significantly lower in tumor tissues compared with normal tissues. Several insertion mutations were detected in different exons of the analyzed hBDs. However, no methylation in any hBDs promoters was detected because of the limited number of CpG islands in these regions. We demonstrated for the first time a link between hBD expression and colon cancer. This suggests that there is a significant link between innate immunity deregulation through disruption of cationic peptides (hBDs) and the potential development of colon cancer

Clinical data of patients diagnosed with colon cancer via colonoscopy.

<p>Clinical data of patients diagnosed with colon cancer via colonoscopy.</p

Differents structures of hBDs: hBD-1 (panel A), hBD2 (Panel B), and hBD3mutant and wild type (panel C and D).

<p>Differents structures of hBDs: hBD-1 (panel A), hBD2 (Panel B), and hBD3mutant and wild type (panel C and D).</p

Human beta defensin (hBD) protein expression in colon cancer tissues.

<p>Tissues were immunostained using specific hBD antibodies (Panel 2A). hBD- positive cells in the tissues were estimated as follows: 0 points, no positive color; 1 point, <20% positive staining; 2 points, 21‑50% positive staining; 3 points, 51–75% positive staining; and 4 points, >75% positive staining. This is presented in Panel B.</p

Predicted effect of the mutations affecting hBD-3 on protein structure stability.

<p>^apredicted protein thermal stability change (∆∆G in Kcal/mol) of mutation from CUPSAT program.</p><p>^brelative solvent accessibility of the wild type residue computed from PoP MuSiC program.</p><p>^cpridected protein stability change (∆∆G in Kcal/mol) of mutation from PoP MuSiC program.</p><p>Predicted effect of the mutations affecting hBD-3 on protein structure stability.</p

Summary of hBDs mutations and their nature/location found in colon cancer tissues.

<p>N = Normal colon tissue</p><p>T = Tumor</p><p>Summary of hBDs mutations and their nature/location found in colon cancer tissues.</p