Prognostic Significance of Cyclin D1 Over-expression in Colorectal Cancer: An Experience from Madinah,Saudi Arabia

Background and study aim: Cyclin D1 is a key regulatory protein in the cell cycle and is over-expressed inmany tumors, including endometrial, thyroid, urothelial, breast, brain gliomas, and esophageal cancers. The mainaim of the present study is to examine the expression pattern of cyclin D1 and its correlation with the differentclinicopathological features in patients with colorectal camcer (CRC) from the Madinah region of Saudi Arabia.Patients and methods: The archival tumor blocks were analyzed using immunohistochemistry for Cyclin D1over-expression in 324 CRC patients diagnosed from January 2006 to December 2017, at the Department of Pathology,King Fahad Hospital, Madinah, Saudi Arabia. Results: Cyclin D1 over-expression was absent in normal mucosa, while15% cases of adenoma showed its over-expression. In CRC, Cyclin D1 was expressed at high levels in 24.1% of case.No significant correlation was observed between Cyclin D1 over-expression and age, gender, tumor size, type andlocation. However, Cyclin D1 over-expression exhibited a significant correlation with tumor differentiation (p=0.04),lymph node involvement (p=0.001), lymphovascular invasion (p=0.001), distant metastasis (p=0.006) and AJCC staging(p=0.001). The Kaplan-Meir analysis revealed a shorter period of survival with Cyclin D1 over-expression (p=0.000).The Cox-regression model analysis showed that Cyclin D1 over-expression was an independent prognostic markerin CRC (p=0.000). Conclusion: Cyclin D1 over-expression increases during normal-adenoma-carcinoma sequence.The significant association observed between Cyclin D1 over-expression, advanced tumor stage and short survivalperiod clearly suggest the role of Cyclin D1 in the carcinogenesis and progression of CRC.     

Rare β-Globin Gene Mutations in Pakistan

The aim of this study was to analyze the rare β-thalassemia (β-thal) mutations in the Pakistani population. A total of 8716 unrelated Pakistani individuals having children with transfusion-dependent thalassemia were investigated by amplification refractory mutation system-polymerase chain reaction (ARMS-PCR) for the previously reported common and rare β-thal mutations. Genomic sequencing of the β-globin gene and its immediate 5' and 3' flanking regions was done where no known mutation was found. Out of the 8716 individuals studied, 88 (1.0%) were not characterized by ARMS-PCR. Genomic sequencing revealed that 67 (0.82%) individuals had 19 different β-thal mutations including one novel mutation (HBB: c.136delT). The remaining 21 (0.26%) individuals did not show any mutation on the β-globin gene and its immediate flanking regions. The characterized alleles included seven (0.09%) in the 5' untranslated region (5'UTR), 29 (0.35%) in the coding regions, and 31 (0.38%) in the splice junction regions. HBB: c.92+1G>A and HBB: c.113G>A were the most frequently seen rare mutations. The spectrum of β-thal mutations in the Pakistani population is very diverse. In addition to the already reported mutations, another 19 different types of mutations were found. Interestingly, 21 individuals who had children with transfusion-dependent thalassemia and one known β-thal mutation, did not show any mutation on the β-globin gene. HBB: c.92+1G>A and HBB: c.113G>A are the most frequently seen rare mutations in Pakistan.     

In vivo brain microdialysis: advances in neuropsychopharmacology and drug discovery

INTRODUCTION: Microdialysis is an important in vivo sampling technique, useful in the assay of extracellular tissue fluid. The technique has both pre-clinical and clinical applications but is most widely used in neuroscience. The in vivo microdialysis technique allows measurement of neurotransmitters such as acetycholine (ACh), the biogenic amines including dopamine (DA), norepinephrine (NE) and serotonin (5-HT), amino acids such as glutamate (Glu) and gamma aminobutyric acid (GABA), as well as the metabolites of the aforementioned neurotransmitters, and neuropeptides in neuronal extracellular fluid in discrete brain regions of laboratory animals such as rodents and non-human primates. AREAS COVERED: In this review we present a brief overview of the principles and procedures related to in vivo microdialysis and detail the use of this technique in the pre-clinical measurement of drugs designed to be used in the treatment of chemical addiction, neurodegenerative diseases such as Alzheimer's disease (AD), Parkinson's disease (PD) and as well as psychiatric disorders such as attention-deficit/hyperactivity disorder (ADHD) and schizophrenia. This review offers insight into the tremendous utility and versatility of this technique in pursuing neuropharmacological investigations as well its significant potential in rational drug discovery. EXPERT OPINION: In vivo microdialysis is an extremely versatile technique, routinely used in the neuropharmacological investigation of drugs used for the treatment of neurological disorders. This technique has been a boon in the elucidation of the neurochemical profile and mechanism of action of several classes of drugs especially their effects on neurotransmitter systems. The exploitation and development of this technique for drug discovery in the near future will enable investigational new drug candidates to be rapidly moved into the clinical trial stages and to market thus providing new successful therapies for neurological diseases that are currently in demand.     

Autozygosity mapping of a large consanguineous Pakistani family reveals a novel non-syndromic autosomal recessive mental retardation locus on 11p15-tel

Autosomal recessive inherited mental retardation is an extremely heterogeneous disease and accounts for approximately 25% of all non-syndromic mental retardation cases. Autozygosity mapping of a large consanguineous Pakistani family revealed a novel locus for non-syndromic autosomal recessive mental retardation (NS-ARMR). The affected individuals showed low IQ and cognitive impairment without any neurological, skeletal, and biochemical abnormalities. All known NS-ARMR genes were excluded by STS markers, so autozygosity mapping by microarray single-nucleotide polymorphism (SNP) analysis were done in all sampled individuals in the family. The nuclear central loop in the five generation family showed homozygosity for a 6-Mb telomeric region on 11p15, whereas all other linkage regions were excluded by calculation of logarithm of odds (LOD) for the SNP microarray data. A maximum LOD score of Z = 3.31 was calculated for the mapped region. These results suggest a novel genetic locus, MRT17, for NS-ARMR.     

Chemopreventive Effects of RXR-Selective Rexinoid Bexarotene on Intestinal Neoplasia of ApcMin/+ Mice

Retinoid X receptor (RXR) has been implicated in several neoplastic diseases. Previously, we have shown that RXR-α is downregulated in human and rodent colonic tumors, suggesting a potential target for colon cancer prevention (http://www.cancer.org/Cancer/ColonandRectumCancer/DetailedGuide/colorectal-cancer-key-statistics). Experiments were designed to assess the chemopreventive efficacy of the selective RXR agonist bexarotene for the suppression of intestinal tumorigenesis in Apc^Min/+ mice. Before the efficacy studies, we determined that the maximal tolerated dose in C57BL/6J mice was less than 400 ppm. For the efficacy study, 6-week-old male and female C57BL/6J-Apc^Min/+ mice (nine mice per group) were fed diets containing 0, 30, and 60 ppm of bexarotene or 200 ppm of bexarotene for 80 days before intestinal tumors were evaluated. Dietary administration of 30 and 60 ppm of bexarotene suppressed the intestinal polyp formation by 38% (P < .015) and 60% (P < .0001) in males, respectively, and by 8.5% and 37% (P < .007) in females, respectively. Also, significant inhibition (50%–100%) of colonic tumor formation was observed in both male and female mice with bexarotene treatment. Administration of 200 ppm of bexarotene showed significant suppression of tumor formation (66%, P < .0001); however, it had significant toxicity. Intestinal tumors of bexarotene-fed mice showed significantly reduced expression of proliferating cell nuclear antigen (60%, P < .0001), cyclin D1, and cyclooxygenase 2 and increased RXR-α messenger RNA and uptake of oleate (34%, P < .01). Also, bexarotene-fed mice showed dose-dependent suppression of serum triglycerides (25%–72%, P < .0001) and inflammatory cytokines.     

p53-stabilizing Agent CP-31398 Prevents Growth and Invasion of Urothelial Cancer of the Bladder in Transgenic UPII-SV40T Mice

The high prevalence of bladder cancer and its recurrence make it an important target for chemoprevention. About half of invasive urothelial tumors have mutations in p53. We determined the chemopreventive efficacy of a p53-stabilizing agent, CP-31398, in a transgenic UPII-SV40T mouse model of bladder transitional cell carcinoma (TCC) that strongly resembles human TCC. After genotyping, six-week-old UPII-SV40T mice (n = 30/group) were fed control (AIN-76A) or experimental diets containing 150 or 300 ppm of CP-31398 for 34 weeks. Progression of bladder cancer growth was monitored by magnetic resonance imaging. At 40 weeks of age, all mice were killed; urinary bladders were collected to determine weights, tumor incidence, and histopathology. There was a significant increase in bladder weights of transgenic versus wild-type mice (male: 140.2 mg vs 27.3 mg, P < .0001; female: 34.2 mg vs 14.8 mg, P < .0001). A significant decrease in the bladder tumor weights (by 68.6–80.2%, P < .0001 in males and by 36.9–55.3%, P < .0001 in females) was observed in CP-31398-treated mice. Invasive papillary TCC incidence was 100% in transgenic mice fed control diet. Both male and female mice exposed to CP-31398 showed inhibition of invasive TCC. CP-31398 (300 ppm) completely blocked invasion in female mice. Molecular analysis of the bladder tumors showed an increase in apoptosis markers (p53, p21, Bax, and Annexin V) with a decrease in vascular endothelial growth factor in transgenic mice fed CP-31398. These results suggest that p53-modulating agents can serve as potential chemopreventive agents for bladder TCC.     

Childhood tumors of the brain: demographic pattern over a ten-year period in the Kashmir Valley

Brain tumors in children represent the second most frequent tumors in this age group after hematologic malignancies. We highlight the demographic pattern after retrospective analysis of brain tumors in children from geographically and ethnically distinct Kashmir Valley managed in our center between 2000 and 2009. We had a total of 248 pediatric patients with brain tumors. The parameters analyzed were age, gender, location of tumors and histopathological subtypes as well as WHO grade of tumor. We also did a comparison between the frequencies of common varieties of tumor in the first and second 5-year periods. We found that 111 tumors (44.75%) were supratentorial, and 137 (55.25%) were infratentorial. The male-to-female ratio was 1.4:1. The proportions of low-grade and high-grade tumors were 60 and 40%, respectively. The most common tumor in our series was astrocytoma. The most common tumors in the supratentorial and infratentorial compartments were craniopharyngioma and medulloblastoma, respectively. Our experience reflects a different demographic profile of pediatric brain tumors as compared with other regions of the world.