Ahmad Shariftabrizi

Naltrexone, an opioid receptor antagonist, attenuates liver fibrosis in bile duct ligated rats

Aim: The aim of this study was to investigate the hypothesis that the opioid system is involved in the development of hepatic fibrosis. Methods: The effect of naltrexone (an opioid receptor antagonist) on hepatic fibrosis in bile duct ligated (BDL) or sham rats was assessed by histology and hepatic hydroxyproline levels. Liver matrix metalloproteinase 2 (MMP-2) was measured by zymography, and α smooth muscle actin (α-SMA) and CD45 (leucocyte common antigen) by immunohistochemistry. The redox state of the liver was assessed by hepatic glutathione (GSH)/oxidised glutathione (GSSG) and S-nitrosothiol levels. Subtypes of opioid receptors in cultured hepatic stellate cells (HSCs) were characterised by reverse transcriptase-polymerase chain reaction, and the effects of selective δ opioid receptor agonists on cellular proliferation, tissue inhibitor of metalloproteinase 1 (TIMP-1), and procollagen I expression in HSCs determined. Results: Naltrexone markedly attenuated the development of hepatic fibrosis as well as MMP-2 activity (p<0.01), and decreased the number of activated HSCs in BDL rats (p<0.05). The development of biliary cirrhosis altered the redox state with a decreased hepatic GSH/GSSG ratio and increased concentrations of hepatic S-nitrosothiols, which were partially or completely normalised by treatment with naltrexone, respectively. Activated rat HSCs exhibited expression of δ1 receptors, with increased procollagen I expression, and increased TIMP-1 expression in response to δ1 and δ2 agonists, respectively. Conclusions: This is the first study to demonstrate that administration of an opioid antagonist prevents the development of hepatic fibrosis in cirrhosis. Opioids can influence liver fibrogenesis directly via the effect on HSCs and regulation of the redox sensitive mechanisms in the liver.

Differential Expression of Cancer Stem Cell Markers ALDH1 and CD133 in Various Lung Cancer Subtypes

Cancer stem cells (CSCs) are hypothesized to be the main culprit of lung cancer progression. Clinicopathological significance of stem cell markers CD133 and ALDH1 in a large group of lung cancer patients was evaluated. ALDH1 and CD133 had higher expression levels in the NSCLC compared to the SCLC. Over-expression of both ALDH1 and CD133 markers was exclusively found in SCC and ADC. Low level of ALDH1 expression was strongly correlated with poor differentiation in ADC cases. Thus, ALDH1high/CD133high phenotype can be considered as a CSC marker in some lung cancer subtypes.

ALDH1 in Combination with CD44 as Putative Cancer Stem Cell Markers are Correlated with Poor Prognosis in Urothelial Carcinoma of the Urinary Bladder

BACKGROUND The aldehyde dehydrogenase 1 family member A1 (ALDH1A1) is one of the promising markers for identifying cancer stem cells in many cancer types, along with other markers including CD44. The aim of the present study was to evaluate the expression and clinical significance of putative cancer stem cell markers, CD44 and ALDH1A1, in a series of urothelial carcinomas of urinary bladder (UCUB) by tissue microarray (TMA). MATERIALS AND METHODS A total of 159 Urothelial Carcinomas (UC) including 96 (60%) low grade and 63 (40%) high grade carcinomas were immunohistochemically examined for the expression of CD44 and ALDH1A1. Correlations of the relative expression of these markers with clinicopathological parameters were also assessed. RESULTS High level expression of ALDH1A1 was found in 16% (25/159) of bladder UC which was significantly correlated with increased tumor size (p value=0.002), high grade (p value<0.001), pathologic stage (T1, p value=0.007 and T2, p value<0.001) and increased rate of recurrence (p value=0.013). A high level of CD44 expression was found in 43% (68/159) of cases, being positively correlated with histologic grade (p value=0.032) and recurrence (p value=0.039). CONCLUSIONS Taken together, our results showed that ALDH1 was concurrently expressed in a fraction of CD44+ tumors and its expression correlated with poor prognosis in UCs. ALDH1A1 could be an ideal marker for targeted therapy of UCs in combination with conventional therapies, particularly in patients with high grade carcinomas. These findings indicate that cells expressing ALDH1A1 along with CD44 can be a potential therapeutic target in bladder carcinomas.

Expression of Stem Cell Markers, CD133 and CD44, in Pediatric Solid Tumors: A Study Using Tissue Microarray

Based on the cancer stem cell (CSC) concept model, a small population of cells with unique self-renewal properties and malignant potential exists in tumors. Immunohistochemistry was performed to detect the expression of CSC markers, CD133 and CD44, in a series of pediatric tumors. The association between expression of these markers and tumor characteristics was then analyzed. In Wilms tumors (WT), a significant positive correlation was found between expression of CD133 and the National Wilms Tumor Stage (NWTS) (p = 0.047). In neuroblastomas (NB), expression of CD133 was positively correlated with the International Neuroblastoma Staging System (INSS) (p-value = 0.012), indicating that the rate of CD133 positivity increased with the stage of these tumors. CD133, as a putative stem cell marker, is associated with more advanced stages of Wilms and NB tumors; therefore, this molecule can be a potential clinical prognostic marker in children suffering from NB or Wilms tumor.

Anti-leukemic and anti-angiogenesis efficacy of arsenic trioxide in new cases of acute promyelocytic leukemia

Arsenic trioxide is now considered the standard agent in treatment of refractory cases of acute promyelocytic leukemia (APL). This drug is also shown to have anti-angiogenesis effect against APL cells in vitro. This study evaluated clinical efficacy and anti-angiogenesis effect of arsenic trioxide in 17 new cases of APL. Arsenic trioxide was given in a dosage of 0.15 mg kg−1 and remission rate, survival rate, toxicities and effect on vascular density of bone marrow was studied. The bone marrow vascular density was examined using immunohistochemistry for von Willebrand Factor (vWF) and CD31 markers. Bone marrow vascular density was determined by calculating mean vessel number in 3 hot spot, high power microscopic fields. Bone marrow vascular density was reduced as identified by anti-vWF immunohistochemical staining (Mean before treatment = 201.6 mm−2 ± 20.4 (SEM), mean after treatment = 109.4 ± 17.2 (SEM), p < 0.001) and anti-CD31 immunostaining (mean before treatment = 199.17 mm−2 ± 21.5 (SEM), mean after treatment = 99.5 mm−2 ± 22.1 (SEM), p < 0.05). Treatment efficacy results showed 100% complete remission rate after median of 30 days and 72% survival rate after median 860 days of follow-up. Main toxicities included hyper-leukocytosis, hepatic toxicity and APL differentiation syndrome. The results imply that arsenic trioxide is an effective anti-leukemia and anti-angiogenesis agent in new cases of APL.

Clinical significance of putative cancer stem cell marker CD44 in different histological subtypes of lung cancer

BACKGROUND According to the cancer stem cell theory, tumors originate from a subset of cells known as cancer stem cells (CSCs) that are responsible for tumor initiation, resistance and relapse. CD44 is a cell adhesion molecule that can aid in the identification of CSCs in various malignancies. OBJECTIVE The purpose of the current study is to evaluate the expression level and clinical significance of CD44 in lung cancer samples. METHODS One hundred and ninety-five lung tumor samples including 74 (38%) squamous cell carcinomas (SCC), 61 (31%) adenocarcinomas (ADC), 23 (12%) large cell carcinoma (LCC) in non-small cell lung cancer (NSCLC) group and 37 (19%) small cell lung cancer (SCLC) samples were examined for the expression of CD44 using immunohistochemistry method. The correlation of CD44 expression with clinicopathological parameters as well as Ki-67 status was also assessed. RESULTS Univariate analysis demonstrated that CD44 expression was significantly higher in NSCLC compared to SCLC (P < 0.001). Among NSCLC, higher level of CD44 expression was found in SCC compared to ADC (P< 0.001) and LCC (P=0.046). Increased expression of CD44 was significantly correlated with higher grade tumors which correspond to poor prognosis in SCC (P=0.012) and the lower level of CD44 expression was more often found in well differentiated ADC tumors (P=0.03). In addition, high expression of CD44 was significantly associated with decreased level of proliferative marker Ki-67 (P=0.04). CONCLUSIONS CD44 could be a valuable tool for the study of lung CSCs and provide a novel therapeutic target for treatment of the patients with lung cancer in combination with conventional therapy.

Dose-dependent modulation of systemic lipid peroxidation and activity of anti-oxidant enzymes by vitamin E in the rat

Abstract The objective of this work was to examine the time-dependent pro-oxidant versus antioxidant effect of various doses of vitamin E used commonly in experimental studies. Erythrocyte activity of superoxide dismutase (SOD), glutathione peroxidase (GPX), catalase (CAT) and plasma lipid peroxidation levels were investigated following biweekly intramuscular administration of 100, 300 and 600 mg/kg of vitamin E at a baseline time point, and additionally at 2, 4 and 6 weeks after initiating treatment. Vitamin E had an antioxidant effect when administered at low doses over short time periods, and increased the activity of antioxidant enzymes. At higher doses and over longer time periods, it increased the level of lipid peroxidation, and attenuated the activity of antioxidant enzymes. These results suggest that time-dependent variations in vitamin E effects should be considered in design and interpretation of experimental antioxidant studies, as well as during clinical trials.

Opioid system blockade decreases collagenase activity and improves liver injury in a rat model of cholestasis

Background:  Following bile duct ligation (BDL) endogenous opioids accumulate in plasma and play a role in the pathophysiology and manifestation of cholestasis. Evidence of centrally mediated induction of liver injury by exogenous opioid agonist administration, prompts the question of whether opioid receptor blockade by naltrexone can affect cholestasis‐induced liver injury.

Comparative expression analysis of putative cancer stem cell markers CD44 and ALDH1A1 in various skin cancer subtypes

Introduction Skin cancers, particularly melanoma, are initiated and maintained by a subpopulation of tumor cells expressing stemness markers that are called cancer stem cells (CSCs). This study aimed to evaluate the expression levels and clinicopathological significance of the putative CSC markers CD44 and ALDH1A1 in patients with skin cancer. Methods The expression levels of CD44 and ALDH1A1 were investigated in 107 skin cancer specimens including 58 (54%) basal cell carcinomas (BCC), 37 (35%) squamous cell carcinomas (SCC), and 12 (11%) melanomas using the tissue microarray (TMA) technique. The correlation of the expression levels of these markers and clinicopathological parameters was then analyzed. Results The expression levels of CD44 and ALDH1A1 were significantly higher in melanoma patients than patients with SCC or BCC (p<0.001 and p = 0.002, respectively). A higher level of CD44 expression was more often found in melanoma tumor cells with a higher rate of recurrence (p = 0.029) and in SCC cases with ulceration (p = 0.01), while there was no significant correlation between ALDH1A1 expression and other clinicopathological parameters. Similarly, coexpression of CD44 and ALDH1A1 (CD44high/ALDH1A1high) was significantly observed in melanoma samples (p<0.001). Conclusions These findings suggest that a CD44high/ALDH1A1high phenotype in melanoma and a CD44high phenotype in SCC can be considered candidates for targeted therapy of skin cancers aiming at CSCs.

Time- and dose-dependent differential regulation of copper-zinc superoxide dismutase and manganese superoxide dismutase enzymatic activity and mRNA level by vitamin E in rat blood cells

Abstract Background Vitamin E is the most important lipid-soluble antioxidant. Recently, it has been proposed as a gene regulator, and its gene modulation effects have been observed at different levels of gene expression and cell signaling. This study was performed to investigate the effects of vitamin E on the activity and expression of the most important endogenous antioxidant enzyme, superoxide dismutase (SOD), in rat plasma. Methods Twenty-eight male Sprauge–Dawley rats were divided into four groups: control group and three dosing groups. The control group received the vehicle (liquid paraffin), and the dosing groups received twice-weekly intraperitoneal injections of 10, 30, and 100 mg/kg of vitamin E ((±)-α-Tocopherol) for 6 weeks. Quantitative real-time reverse transcription-polymerase chain reaction and enzyme assays were used to assess the levels of Cu/Zn-SOD and Mn-SOD mRNA and enzyme activity levels in blood cells at 0, 2, 4, and 6 weeks following vitamin E administration. Catalase enzyme activity and total antioxidant capacity were also assessed in plasma at the same time intervals. Results Mn-SOD activity was significantly increased in the 100 and 30 mg/kg dosing groups after 4 and 6 weeks, with corresponding significant increase in their mRNA levels. Cu/Zn-SOD activity was not significantly changed in response to vitamin E administration at any time points, whereas Cu/Zn-SOD mRNA levels were significantly increased after longer time points with high doses (30 and 100 mg/kg) of vitamin E. Catalase enzyme activity was transiently but significantly increased after 4 weeks of vitamin E treatment in 30 and 100 mg/kg dosing groups. Total antioxidant status was significantly increased after 4 and 6 weeks in the 100 mg/kg dosing group. Conclusion Only the chronic administration of higher doses of alpha-tocopherol is associated with the increased activity and expression of Mn-SOD in rats. Cu/Zn-SOD activity and expression does not dramatically change in response to vitamin E.