Publications by authors named "Mekky Abouzied"

21 Publications

  • Page 1 of 1

Identification of Chemo and Radio-resistant Sub-population of Stem Cells in Human Cervical Cancer HeLa Cells.

Cancer Invest 2021 Jun 2:1-27. Epub 2021 Jun 2.

Department of Regenerative Medicine, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, 2630 Sugitani, Toyama 930-0194, Japan.

Background: Cervical cancer ranks the second female malignancy after breast cancer. Cancer stem cells (CSCs) are hard to be eradicated, so can recur. We aim to isolate and characterize CSCs from HeLa cells.

Methods: These cells express clusters of differentiation (CDs), 44 and 24, to be sorted by fluorescence-activated cell sorting (FACS).

Results: CD44 + CD24+ cells showed potential to form spheres, tumorigenicity, stemness genes and higher resistance to cisplatin, X-ray.

Conclusion: CD44CD24 HeLa cells hold characteristics of CSCs, , studies, suggested that targeting of them lead to screening of new anti-cancer therapies.
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http://dx.doi.org/10.1080/07357907.2021.1931875DOI Listing
June 2021

Generation of Combinatorial Lentiviral Vectors Expressing Multiple Anti-Hepatitis C Virus shRNAs and Their Validation on a Novel HCV Replicon Double Reporter Cell Line.

Viruses 2020 09 18;12(9). Epub 2020 Sep 18.

Department of Molecular Medicine, University of Padua, 35121 Padua, Italy.

Despite the introduction of directly acting antivirals (DAAs), for the treatment of hepatitis C virus (HCV) infection, their cost, patient compliance, and viral resistance are still important issues to be considered. Here, we describe the generation of a novel JFH1-based HCV subgenomic replicon double reporter cell line suitable for testing different antiviral drugs and therapeutic interventions. This cells line allowed a rapid and accurate quantification of cell growth/viability and HCV RNA replication, thus discriminating specific from unspecific antiviral effects caused by DAAs or cytotoxic compounds, respectively. By correlating cell number and virus replication, we could confirm the inhibitory effect on the latter of cell over confluency and characterize an array of lentiviral vectors expressing single, double, or triple cassettes containing different combinations of short hairpin (sh)RNAs, targeting both highly conserved viral genome sequences and cellular factors crucial for HCV replication. While all vectors were effective in reducing HCV replication, the ones targeting viral sequences displayed a stronger antiviral effect, without significant cytopathic effects. Such combinatorial platforms as well as the developed double reporter cell line might find application both in setting-up anti-HCV gene therapy approaches and in studies aimed at further dissecting the viral biology/pathogenesis of infection.
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http://dx.doi.org/10.3390/v12091044DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7551853PMC
September 2020

The metabolic disorders associated with chronic consumption of soft and energy drinks in rats.

Acta Biochim Pol 2020 Mar;67(1):79-84

1Department of Pharmacology and Toxicology (subdivision of Biochemistry), College of Pharmacy, Taibah University, Medina, Kingdom of Saudi Arabia; 2Department of Biochemistry, Faculty of Pharmacy, Minia University, Minia, Egypt.

Background: Energy Drinks (EDs) and Soft Drinks (SDs) are widely consumed among adolescents and young adults. These drinks contain variable amounts of caffeine which is a central nervous system stimulator; in addition to sugar, taurine, vitamins and herbal extracts. Several adverse effects have been reported for the excessive consumption of caffeine and sugar.

Aim: This work aimed at providing a comparison between the effect of chronic consumption of both drinks on metabolism biochemically as well as at the histopathological level.

Methods: Adult albino rats were randomly divided into three groups and treated for 4 weeks. Animals received water (control, group 1), 12.5 ml/kg/day of either Pepsi® (SD, group 2) or Power Horse® (ED, group 3). All animals had free access to water and standard animal chow.

Results: ED and SD groups showed a significant weight gain compared to control. ED animals showed a significant increase in serum urea, hyperlipidemia and hyperglycemia in comparison to control and SD groups. Serum uric acid significantly increased in ED and SD groups. ED group showed congestion and inflammation in their renal tissues in addition to splenomegaly and increased phagocyte infiltration.

Conclusion: The high caffeine-sugar content in ED exerts a more significant influence on the metabolic pathways than SDs. Both increase the incidence of cardiovascular diseases and tissue inflammation due to their effect on lipid profile and blood glucose. The other ingredients in EDs may play a role in the observed metabolic disturbances. Chronic use of EDs should be especially discouraged to avoid these negative effects.
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http://dx.doi.org/10.18388/abp.2020_2914DOI Listing
March 2020

Antioxidant, anti-inflammatory and anti-fibrotic effects of gum resin in CCl-induced hepatotoxicity.

Exp Ther Med 2020 Feb 19;19(2):1313-1321. Epub 2019 Dec 19.

Department of Pharmacology and Toxicology, College of Pharmacy, Taibah University, Medina 11564, Kingdom of Saudi Arabia.

The present study aims to investigate the potential antioxidant, anti-inflammatory and anti-fibrotic effects of Boswellia serrate (BS) gum resin against carbon tetrachloride (CCl)-induced liver damage. Four groups consisting of eight rats each were designated: Group I, normal healthy control; group II, CCl-induced liver fibrosis; group III, CCl-induced liver fibrosis followed by BS treatment daily for two weeks; and group IV, CCl-induced liver fibrosis followed by silymarin treatment daily for two weeks. Expression of tumor necrosis factor-α (TNF-α) and nuclear factor κB (NF-κB), interleukin-6 (IL-6), transforming growth factor-β (TGF-β) and cyclooxygenase-2 (COX-2) were assessed, in addition to histopathological and fibrotic changes in liver tissues isolated from the rats. BS significantly ameliorated CCl-induced increases in serum aspartate (AST) and alanine transaminase (ALT) levels, reduced lactate dehydrogenase (LDH) activities in addition to restoring total bilirubin, triglyceride and albumin levels. BS treatment also alleviated oxidative stress and improved total antioxidant capacity in the liver, and reduced the expression of TNF-α, NF-κB, TGF-β, IL-6 and COX-2. On a histopathological level, BS treatment also exhibited antifibrotic activity. In conclusion, these findings suggest that BS contains potentially hepatoprotective effects against CCl4-induced liver injury via its antioxidant, anti-inflammatory and antifibrotic characteristics.
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http://dx.doi.org/10.3892/etm.2019.8353DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6966228PMC
February 2020

Molecular Mechanisms of Natural Honey Against H. pylori Infection Via Suppression of NF-κB and AP-1 Activation in Gastric Epithelial Cells.

Arch Med Res 2016 07;47(5):340-348

Department of Biochemistry, Faculty of Pharmacy, Minia University, Minia, Egypt.

Background And Aims: Natural honey has been used as a medicine since ancient times. Honey is widely known for its antibacterial properties against H. pylori; however, the mechanisms of its antibacterial activity are not fully known. The present study was performed to examine the molecular mechanisms by which natural honey can inhibit H. pylori infection in gastric epithelial cells.

Methods: Electrophoretic mobility shift assay was used to measure NF-κB- and AP-1-DNA binding activity. Western blotting was used to detect IκB-α and COX-2 expression.

Results: H. pylori induced NF-κB and AP-1 DNA-binding activity in gastric epithelial cells. Manuka honey inhibited H. pylori-induced NF-κB and AP-1 in a time- and dose-dependent manner. Maximum inhibition of H. pylori-induced NF-κB and AP-1 by manuka honey was observed at concentrations of 20% at 1-2 h. Pre-treatment of AGS cells with other commercial natural honeys also inhibited H. pylori-induced NF-κB and AP-1 DNA-binding activity. Honey prevented H. pylori-induced degradation of IκB-α protein and downregulated COX-2 protein levels.

Conclusions: Our findings suggest that natural honey exerts its inhibitory effects against H. pylori by inhibiting NF-κB and AP-1 activation and downregulation of COX-2 expression. These results provide new mechanistic insights into honey effects in the suppression of H. pylori infection.
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http://dx.doi.org/10.1016/j.arcmed.2016.09.002DOI Listing
July 2016

Hepatoprotective activity of ethanolic extract of Salix subserrata against CCl4-induced chronic hepatotoxicity in rats.

BMC Complement Altern Med 2016 Jul 29;16:263. Epub 2016 Jul 29.

Department of Pharmacology and Toxicology, College of Pharmacy, Taibah University, Medina, Kingdom of Saudi Arabia.

Background: The liver performs diverse functions that are essential for life. In the absence of reliable liver protective drugs, a large number of natural medicinal preparations are used for the treatment of liver diseases. Therefore the present study aims to investigate the hepatoprotective effects of Salix subserrata Willd flower ethanolic extract (SFEE) against carbon tetrachloride (CCl4)-induced liver damage.

Methods: Rats were divided into 4 groups of 10 animals each. Group I served as the normal healthy control, groups II rats were intoxicated with CCl4 i.p. (0.8 ml/kg body weight CCl4/olive oil, twice weekly for 9 weeks), group III rats received CCl4 i.p. and SFEE orally (150 mg/kg daily) and group IV rats received CCl4 i.p. and Silymarin orally (100 mg/kg, daily). The hepatoprotective potential of SFEE in rats was evaluated by measuring the protein levels of two inflammatory biomarkers; tumor necrosis factor-alpha (TNF-α) and nuclear factor kappa-B (NF-kB) in addition to other liver biomarkers. Histopathological changes in the liver were assessed using hematoxylin and eosin staining (HE).

Results: The administration of SFEE showed hepatic protection at an oral dose of 150 mg/kg. SFEE significantly reduced the elevated serum levels of intracellular liver enzymes as well as liver biomarkers in comparison to CCl4- intoxicated group. Notably, SFEE significantly reduced the expression levels of TNF-α and NFkB proteins compared to their levels in CCl4 intoxicated group. These findings were confirmed with the histopathological observations, where SFEE was capable of reversing the toxic effects of CCl4 on liver cells compared to that observed in CCl4-intoxicated animals.

Conclusion: Our results show that SFEE has potential hepatoprotective effects at 150 mg/kg. These effects can be regarded to the antioxidant and anti-inflammatory properties of the extract.
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http://dx.doi.org/10.1186/s12906-016-1238-2DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4966707PMC
July 2016

Experimental evidence for the therapeutic potential of tempol in the treatment of acute liver injury.

Mol Cell Biochem 2016 Jan 6;411(1-2):107-15. Epub 2015 Oct 6.

Department of Pharmacology & Toxicology, Faculty of Medicine, Assiut University, Assiut, Egypt.

Oxidative stress is one of the mechanisms involved in the acute carbon tetrachloride (CCl4)-induced hepatotoxicity. Since 4-hydroxy-2,2,6,6-tetramethylpiperidin-1-oxyl, known as tempol, has powerful antioxidant properties, we investigated its potential hepatoprotective effects and the underlying mechanisms that may add further benefits for its clinical usefulness using an acute model of CCl4-induced hepatotoxicity. One hour after CCl4 induction of acute hepatotoxicity, mice were treated with a daily dose of 20 mg/kg/day tempol for 3 days. It was found that treatment of animals with tempol significantly negated the pathological changes in liver function parameters as well as histology induced by CCl4. In addition, tempol significantly ameliorated CCl4-induced lipid peroxidation and GSH depletion, and improved catalase activity. Furthermore, tempol alleviated the inflammation induced by CCl4 as indicated by reducing the liver expression level of nuclear factor-kappa B (NF-κB) and tumor necrosis factor-α (TNF-α). Finally, tempol significantly reduced expression level of the B-cell lymphoma-2 protein (Bcl-2) and active caspase-3 which are known markers of apoptosis. In conclusion, the present study provides important evidences for the promising hepatoprotective effects of tempol that can be explained by amelioration of oxidative stress mainly through replenishment of GSH, restoration of antioxidant enzyme activities, and reduction of lipid peroxides alongside its anti-inflammatory properties.
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http://dx.doi.org/10.1007/s11010-015-2572-2DOI Listing
January 2016

Comparative effects of Aliskiren and Telmisartan in high fructose diet-induced metabolic syndrome in rats.

Eur J Pharmacol 2015 Aug 25;760:145-53. Epub 2015 Apr 25.

Department of Pharmacology and Toxicology, Faculty of Pharmacy, Minia University, El-Minia, Egypt.

Fructose is a commonly used sweetener associated with diets that increase the prevalence of metabolic syndrome (MS). Inhibition of the renin-angiotensin system (RAS) has been consistently demonstrated to reduce MS. However, there has been no direct comparison among different pharmacological modes of inhibiting the RAS concerning their effects on MS. This study investigated the effect of aliskiren, a direct renin inhibitor, versus telmisartan, an angiotensin II-receptor blocker, in the treatment of fructose-induced MS in rats. MS was induced by high fructose (FRC) diet feeding for 12 weeks. Oral administrations of telmisartan (TEL, 5 mg/kg), aliskiren (ALS, 30 mg/kg) or vehicle were started in the last 4 weeks. Results showed that administration of either TEL or ALS with FRC diet equally ameliorated the metabolic parameters (glucose level, oral glucose tolerance test, insulin resistance and serum lipids profile), systolic blood pressure and oxidative stress markers (malondialdehyde, nitric oxide, reduced glutathione levels and catalase activity). Additionally, the effects of TEL and ALS were associated with a decrease in body composition index and attenuation of liver index, serum liver enzyme activities and hepatic expressions of inflammatory and fibrotic markers (tumor necrosis factor-α, nuclear factor kappa-B and transforming growth factor-β) with a significant increase in hepatic glucose transporter-2 and peroxisome proliferator-activated receptors-alpha and gamma expressions. The results suggested that, at indicated dosage, ALS has ameliorative effect equal to that of TEL against FRC-induced metabolic and hepatic disorders; implying that drugs which inhibit the RAS, by different mode of inhibition, profoundly affect fructose-induced MS in rats.
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http://dx.doi.org/10.1016/j.ejphar.2015.04.019DOI Listing
August 2015

Estimation of leucine aminopeptidase and 5-nucleotidase increases alpha-fetoprotein sensitivity in human hepatocellular carcinoma cases.

Asian Pac J Cancer Prev 2015 ;16(3):959-63

Departments of Pharmacology and Toxicology, College of Pharmacy, Taibah University, Medina, Kingdom of Saudi Arabia E-mail :

Purpose: To find parameters that can increase alpha-fetoprotein (AFP) sensitivity and so help in accurate diagnosis and rapid management of hepatocullular carcinoma (HCC), as AFP has limited utility of distinguishing HCC from benign hepatic disorders for its high false-positive and false negative rates.

Materials And Methods: Serum levels of AFP, 5'-nucleotidase enzyme activity (5-NU) and leucine aminopeptidase enzyme (LAP) activity were measured in 40 individuals.

Results: LAP and 5'NU were elevated in HCC at p<0.001. Pearson correlation coefficients showed that changes in AFP exhibited positive correlation with both 5'-NU and LAP at (p<0.001). The complementary use of LAP only with AFP resulted in an increase in sensitivity of AFP from 75% to 90% in detecting HCC. The complementary use of both LAP and 5-NU with AFP resulted in an increased sensitivity of AFP in detecting HCC from 75% to 95%.

Conclusions: LAP and 5-FU can be determined in HCC patients in combination with AFP to improve its sensitivity and decrease false negative results.
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http://dx.doi.org/10.7314/apjcp.2015.16.3.959DOI Listing
December 2015

Curcumin ameliorate DENA-induced HCC via modulating TGF-β, AKT, and caspase-3 expression in experimental rat model.

Tumour Biol 2015 Mar 18;36(3):1763-71. Epub 2014 Dec 18.

Department of Pharmacology and Toxicology, College of Pharmacy, Taibah University, El- Madinah El-Munawarah, P.O. Box 30001, Saudi Arabia,

Hepatocellular carcinoma (HCC) is one of the most common malignancies worldwide. In laboratory animal models, diethylnitrosamine (DENA) is a well-known agent that has a potent hepatocarcinogenic effect that is used to induce HCC. As curcumin has a potent anti-inflammatory effect with strong therapeutic potential against a variety of cancers, our present study aims to investigate its curative effects and the possible mechanisms of action against DENA-induced HCC in male rats. Investigation of biochemical and molecular parameters of HCC animal model liver showed an overexpression of TGF-β and Akt proteins accompanied with a significant reduction of the proapoptotic marker caspase-3. DENA-induced hepatic cellular injury resulted also in a significant increase in liver function marker enzymes aspartate aminotransferase (AST), alanine aminotransferase (ALT), and lipid peroxides in this group. Curcumin treatment partially reversed DENA-induced damage as it reduced the overexpression of the angiogenic and anti-apoptotic factors TGF-β and Akt and improved caspase-3 expression. Also, it could partially normalize the serum values of liver marker enzymes and lipid peroxidation and improve liver architecture. Curcumin shows a unique chemotherapeutic effect in reversing DENA-induced HCC in rat model. This effect is possibly mediated through its proapoptotic, antioxidant, anti-angiogenic, as well as antimitotic effects. It interferes and modulates cell signaling pathways and hence turns death signals and apoptosis on within tumor cells.
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http://dx.doi.org/10.1007/s13277-014-2778-zDOI Listing
March 2015

Tempol ameliorates cardiac fibrosis in streptozotocin-induced diabetic rats: role of oxidative stress in diabetic cardiomyopathy.

Naunyn Schmiedebergs Arch Pharmacol 2013 Dec 16;386(12):1071-80. Epub 2013 Aug 16.

Department of Pharmacology and Toxicology, Faculty of Pharmacy, Minia University, 61511, Minya, Egypt,

Long-standing diabetes is associated with increased oxidative stress and cardiac fibrosis. This, in turn, contributes to the progression of cardiomyopathy. The present study was sought to investigate whether the free radical scavenger, 4-hydroxy-2,2,6,6-tetramethyl piperidinoxyl (tempol) can protect against diabetic cardiomyopathy and to explore the specific underlying mechanism(s) in this setting. Diabetes was induced in rats by a single intraperitoneal injection dose of streptozotocin (50 mg/kg). These animals were treated with tempol (18 mg kg(-1) day(-1), orally) for 8 weeks. Our results showed significant increases in collagen IV and fibronectin protein levels and a marked decrease in matrix metalloproteinase-2 (MMP-2) activity measured by gelatin-gel zymography alongside elevated cardiac transforming growth factor (TGF)-β level determined using ELISA or immunohistochemistry in cardiac tissues of diabetic rats compared with control. This was accompanied by an increased in the oxidative stress as evidenced by increased reactive oxygen species (ROS) production and decreased antioxidant enzyme capacity along with elevated lactate dehydrogenase (LDH) and creatine kinase (CK-MB) serum levels as compared with the control. Tempol treatment significantly corrected the changes in the cardiac extracellular matrix, TGF-β, ROS or serum LDH, CK-MB levels, and normalized MMP-2 activity along with preservation of cardiac tissues integrity of diabetic rats against damaging responses. Moreover, tempol normalized the elevated systolic blood pressure and improved some cardiac functions in diabetic rats. Collectively, our data suggest a potential protective role of tempol against diabetes-associated cardiac fibrosis in rats via reducing oxidative stress and extracellular matrix remodeling.
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http://dx.doi.org/10.1007/s00210-013-0904-xDOI Listing
December 2013

Cardioprotective effects of nicorandil, a mitochondrial potassium channel opener against doxorubicin-induced cardiotoxicity in rats.

Basic Clin Pharmacol Toxicol 2013 Sep 1;113(3):158-66. Epub 2013 Jun 1.

Department of Pharmacology and Toxicology, Faculty of Pharmacy, Damanhour University, Damanhour, Egypt.

Doxorubicin is a chemotherapeutic drug used to treat solid and haematopoietic tumours. Its use is limited by a major side effect of cardiotoxicity. It was reported that doxorubicin-induced cardiotoxicity is mediated through oxidative stress coupled with impaired NO bioavailability and NF-κB activation. Nicorandil, a mitochondrial ATP-dependent potassium (KATP ) channel opener, was reported to be cardioprotective on ischaemic myocardium. However, the effect of nicorandil against doxorubicin-induced cardiotoxicity has not yet been clarified. Accordingly, six groups of rats were used. The first three groups were injected with vehicle, nicorandil (3 mg/kg) orally and doxorubicin (a single intraperitoneal injection of 20 mg/kg), respectively. Group four was treated with nicorandil, whereas group five was treated with glibenclamide and then nicorandil starting 2 days before doxorubicin and continued for five consecutive days. Group six was treated with glibenclamide alone. At the end of the experiment, the rats were killed. Cardiac enzyme indexes were measured in serum. Heart tissues were processed for determination of nitrite/nitrate, NF-κB protein expression, glutathione (GSH), lipid peroxide (TBARS) levels and superoxide production. In addition to body-weight reduction, doxorubicin produced cardiotoxicity as indicated from the increase in lactate dehydrogenase (LDH), creatine kinase (CK) activities, TBARS, superoxide production, NF-κB expression and caspase-3 activity. Moreover, doxorubicin decreased GSH and nitrite/nitrate levels. Histopathological examination of doxorubicin-treated hearts revealed degenerative changes. On the other hand, nicorandil protected cardiac tissues against doxorubicin cardiotoxicity as demonstrated from normalization of cardiac biochemical and oxidative stress parameters and amelioration of histopathological changes. Glibenclamide, a blocker of the KATP channel, reversed most of the cardiac effects of nicorandil.
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http://dx.doi.org/10.1111/bcpt.12078DOI Listing
September 2013

Hepatoma-derived growth factor and nucleolin exist in the same ribonucleoprotein complex.

BMC Biochem 2013 Jan 10;14. Epub 2013 Jan 10.

Institute of Biochemistry and Molecular Biology, University of Bonn, Nussallee 11, Bonn 53115, Germany.

Background: Hepatoma-derived growth factor (HDGF) is a protein which is highly expressed in a variety of tumours. HDGF has mitogenic, angiogenic, neurotrophic and antiapoptotic activity but the molecular mechanisms by which it exerts these activities are largely unknown nor has its biological function in tumours been elucidated. Mass spectrometry was performed to analyse the HDGFStrep-tag interactome. By Pull-down-experiments using different protein and nucleic acid constructs the interaction of HDGF and nucleolin was investigated further.

Results: A number of HDGFStrep-tag copurifying proteins were identified which interact with RNA or are involved in the cellular DNA repair machinery. The most abundant protein, however, copurifying with HDGF in this approach was nucleolin. Therefore we focus on the characterization of the interaction of HDGF and nucleolin in this study. We show that expression of a cytosolic variant of HDGF causes a redistribution of nucleolin into the cytoplasm. Furthermore, formation of HDGF/nucleolin complexes depends on bcl-2 mRNA. Overexpression of full length bcl-2 mRNA increases the number of HDGF/nucleolin complexes whereas expression of only the bcl-2 coding sequence abolishes interaction completely. Further examination reveals that the coding sequence of bcl-2 mRNA together with either the 5' or 3' UTR is sufficient for formation of HDGF/nucleolin complexes. When bcl-2 coding sequence within the full length cDNA is replaced by a sequence coding for secretory alkaline phosphatase complex formation is not enhanced.

Conclusion: The results provide evidence for the existence of HDGF and nucleolin containing nucleoprotein complexes which formation depends on the presence of specific mRNAs. The nature of these RNAs and other components of the complexes should be investigated in future.
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http://dx.doi.org/10.1186/1471-2091-14-2DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3551658PMC
January 2013

Overexpression of hepatoma-derived growth factor in melanocytes does not lead to oncogenic transformation.

BMC Cancer 2011 Oct 20;11:457. Epub 2011 Oct 20.

Institute of Biochemistry and Molecular Biology, University of Bonn, Nussallee 11, 53115 Bonn, Germany.

Background: HDGF is a growth factor which is overexpressed in a wide range of tumors. Importantly, expression levels were identified as a prognostic marker in some types of cancer such as melanoma.

Methods: To investigate the presumed oncogenic/transforming capacity of HDGF, we generated transgenic mice overexpressing HDGF in melanocytes. These mice were bred with mice heterozygous for a defective copy of the Ink4a tumor suppressor gene and were exposed to UV light to increase the risk for tumor development both genetically and physiochemically. Mice were analyzed by immunohistochemistry and Western blotting. Furthermore, primary melanocytes were isolated from different strains created.

Results: Transgenic animals overexpressed HDGF in hair follicle melanocytes. Interestingly, primary melanocytes isolated from transgenic animals were not able to differentiate in vitro whereas cells isolated from wild type and HDGF-deficient animals were. Although, HDGF-/-/Ink4a+/- mice displayed an increased number of epidermoid cysts after exposure to UV light, no melanomas or premelanocytic alterations could be detected in this mouse model.

Conclusions: The results therefore provide no evidence that HDGF has a transforming capacity in tumor development. Our results in combination with previous findings point to a possible role in cell differentiation and suggest that HDGF promotes tumor progression after secondary upregulation and may represent another protein fitting into the concept of non-oncogene addiction of tumor tissue.
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http://dx.doi.org/10.1186/1471-2407-11-457DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3213223PMC
October 2011

Hepatoma-derived growth factor-related protein-3: a new neurotrophic and neurite outgrowth-promoting factor for cortical neurons.

J Neurosci Res 2010 Dec 1;88(16):3610-20. Epub 2010 Oct 1.

Institut für Biochemie und Molekularbiologie, Rheinische Friedrich-Wilhelms Universität, Bonn, Germany.

Hepatoma-derived growth factor-related proteins (HRPs) make up a family of six members. Hepatoma-derived growth factor-related protein-3 (HRP-3) is the only family member whose expression is almost restricted to nervous tissue. Here we show that soluble HRP-3 acts as a novel neurotrophic factor for cultured primary cortical neurons. Antibody-mediated neutralization of HRP-3 function results in neuronal degeneration. In contrast, HRP-3 as the only addition to a culture medium not supporting neuronal survival rescues neurons to an extent comparable to the addition of FCS. Besides this neuroprotective capability, the protein exerts a neurite outgrowth-promoting effect when it is presented as a coated substrate but not as a soluble factor. This study points to an important role of HRP-3 during the development of the nervous system.
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http://dx.doi.org/10.1002/jnr.22507DOI Listing
December 2010

Misfolded endoplasmic reticulum retained subunits cause degradation of wild-type subunits of arylsulfatase A heteromers.

FEBS J 2010 Aug 14;277(16):3404-14. Epub 2010 Jul 14.

Institut für Biochemie und Molekularbiologie, Rheinische-Friedrich-Wilhelms Universität Bonn, Bonn, Germany.

Arylsulfatase A is an oligomeric lysosomal enzyme. In the present study, we use this enzyme as a model protein to examine how heteromerization of wild-type and misfolded endoplasmic reticulum-degraded arylsulfatase A polypeptides affects the quality control of wild-type arylsulfatase A subunits. Using a conformation sensitive monoclonal antibody, we show that, within heteromers of misfolded and wild-type arylsulfatase A, the wild-type subunits are not fully folded. The results obtained show that arylsulfatase A polypeptide complexes, rather than the monomers, are subject to endoplasmic reticulum quality control and that, within a heteromer, the misfolded subunit exerts a dominant negative effect on the wild-type subunit. Although it has been shown that mature lysosomal arylsulfatase A forms dimers at neutral pH, the results obtained in the present study demonstrate that, in the early biosynthetic pathway, arylsulfatase A forms oligomers with more than two subunits.
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http://dx.doi.org/10.1111/j.1742-4658.2010.07745.xDOI Listing
August 2010

Hepatoma-derived growth factor-related protein-3 interacts with microtubules and promotes neurite outgrowth in mouse cortical neurons.

J Biol Chem 2009 Apr 23;284(17):11637-51. Epub 2009 Feb 23.

Institut für Biochemie und Molekularbiologie, Rheinische Friedrich-Wilhelms Universität, Nussallee 11, 53115 Bonn, Germany.

Hepatoma-derived growth factor-related proteins (HRP) comprise a family of 6 members, which the biological functions are still largely unclear. Here we show that during embryogenesis HRP-3 is strongly expressed in the developing nervous system. At early stages of development HRP-3 is located in the cytoplasm and neurites of cortical neurons. Upon maturation HRP-3 relocalizes continuously to the nuclei and in the majority of neurons of adult mice it is located exclusively in the nucleus. This redistribution from neurites to nuclei is also found in embryonic cortical neurons maturing in cell culture. We show that HRP-3 is necessary for proper neurite outgrowth in primary cortical neurons. To identify possible mechanisms of how HRP-3 modulate neuritogenesis we isolated HRP-3 interaction partners and demonstrate that it binds tubulin through the N-terminal so called HATH region, which is strongly conserved among members of the HRP family. It promotes tubulin polymerization, stabilizes and bundles microtubules. This activity depends on the extranuclear localization of HRP-3. HRP-3 thus could play an important role during neuronal development by its modulation of the neuronal cytoskeleton.
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http://dx.doi.org/10.1074/jbc.M901101200DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2670168PMC
April 2009

Hepatoma-derived growth factor (HDGF) is dispensable for normal mouse development.

Dev Dyn 2008 Jul;237(7):1875-85

Institute of Physiological Chemistry, University of Bonn, Bonn, Germany.

Hepatoma-derived growth factor (HDGF) is suggested to be involved in organ development and exhibits proliferative, angiogenic, and neurotrophic activity. The in vivo functions are, however, so far unknown. In this study, we generated HDGF-deficient mice, in which parts of the HDGF gene were replaced by a gene encoding green fluorescent protein (eGFP). HDGF-/- mice are viable with no apparent morphological abnormalities. Cultured HDGF-deficient dermal fibroblasts show unaltered proliferation rates and cell-cycle distributions. In contrast to previous studies, our data demonstrate that signal pathways involved in the response to extracellular HDGF do not depend on the presence of intracellular HDGF. Contrary to the reported role of HDGF as a modulator of apoptosis, similar apoptotic rates were found between wild-type and HDGF-deficient fibroblasts following tumor necrosis factor alpha (TNFalpha) -induced apoptosis or cellular stress. The lack of obvious biochemical and morphological phenotypes in HDGF-deficient mice demonstrates that in vivo HDGF is dispensable for normal development in mice.
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http://dx.doi.org/10.1002/dvdy.21589DOI Listing
July 2008

Expression of hepatoma-derived growth factor family members in the adult central nervous system.

BMC Neurosci 2006 Jan 23;7. Epub 2006 Jan 23.

Institut für Physiologische Chemie, Rheinische Friedrich-Wilhelms Universität, Nussallee 11, 53115 Bonn, Germany.

Background: Hepatoma-derived growth factor (HDGF) belongs to a polypeptide family containing five additional members called HDGF related proteins 1-4 (HRP-1 to -4) and Lens epithelial derived growth factor. Whereas some family members such as HDGF and HRP-2 are expressed in a wide range of tissues, the expression of others is very restricted. HRP-1 and -4 are only expressed in testis, HRP-3 only in the nervous system. Here we investigated the expression of HDGF, HRP-2 and HRP-3 in the central nervous system of adult rats on the cellular level by immunohistochemistry. In addition we performed Western blot analysis of various brain regions as well as neuronal and glial cell cultures.

Results: HDGF was rather evenly expressed throughout all brain regions tested with the lowest expression in the substantia nigra. HRP-2 was strongly expressed in the thalamus, prefrontal and parietal cortex, neurohypophysis, and the cerebellum, HRP-3 in the bulbus olfactorius, piriform cortex and amygdala complex. HDGF and HRP-2 were found to be expressed by neurons, astrocytes and oligodendrocytes. In contrast, strong expression of HRP-3 in the adult nervous system is restricted to neurons, except for very weak expression in oligodendrocytes in the brain stem. Although the majority of neurons are HRP-3 positive, some like cerebellar granule cells are negative.

Conclusion: The coexpression of HDGF and HRP-2 in glia and neurons as well as the coexpression of all three proteins in many neurons suggests different functions of members of the HDGF protein family in cells of the central nervous system that might include proliferation as well as cell survival. In addition the restricted expression of HRP-3 point to a special function of this family member for neuronal cells.
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http://dx.doi.org/10.1186/1471-2202-7-6DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1363353PMC
January 2006

Hepatoma-derived growth factor. Significance of amino acid residues 81-100 in cell surface interaction and proliferative activity.

J Biol Chem 2005 Mar 17;280(12):10945-54. Epub 2005 Jan 17.

Institut für Physiologische Chemie, Rheinische Friedrich-Wilhelms Universität, Nussallee 11, 53115 Bonn, Germany.

Hepatoma-derived growth factor (HDGF) has proliferative, angiogenic, and neurotrophic activity. It plays a putative role in the development and progression of cancer. When expressed in cells, the mitogenic activity of HDGF depends on its nuclear localization, but it also stimulates proliferation when added to the cell culture medium. A cell surface receptor for HDGF has not been identified so far. We investigated the interaction of various purified recombinant HDGF fusion proteins with the cell surface of NIH 3T3 fibroblasts. We showed that binding of a HDGF-beta-galactosidase fusion protein to the cell surface of NIH 3T3 fibroblasts was saturable, occurred with high affinity (K(D) = 14 nm), and had a proliferative effect. We identified a peptide comprising amino acid residues 81-100 within the amino-terminal part of HDGF that bound to the cell surface of NIH 3T3 cells with saturation and affinity values similar to those of HDGF. When added to primary human fibroblasts, this peptide stimulated proliferation. Substitution of a single amino acid (K96A) within this peptide was sufficient to abolish its binding to the cell surface and its proliferative activity. In contrast, when expressed transiently in NIH 3T3 cells, a HDGF-beta-galactosidase fusion protein in which amino acid residues 81-100 were deleted still had proliferative activity, whereas a fusion protein containing only the 81-100 peptide did not. Our results suggest the existence of a plasma membrane-located HDGF receptor for which signaling depends on amino acid residues 81-100 of HDGF. This region differs from the one that has been recently identified to be essential for mitogenic activity depending on the nuclear localization of HDGF. Thus, HDGF exerts its proliferative activity via two different pathways.
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http://dx.doi.org/10.1074/jbc.M414652200DOI Listing
March 2005

Expression patterns and different subcellular localization of the growth factors HDGF (hepatoma-derived growth factor) and HRP-3 (HDGF-related protein-3) suggest functions in addition to their mitogenic activity.

Biochem J 2004 Feb;378(Pt 1):169-76

Institut für Physiologische Chemie, Rheinische Friedrich-Wilhelms Universität, Nussallee 11, 53115 Bonn, Germany.

HDGF (hepatoma-derived growth factor) and the HRPs (HDGF-related proteins) comprise a family of six proteins which display high identity in their N-terminus, but differ at the C-terminus. Here we investigate the patterns of expression of HDGF and HRP-3, by generating antisera specifically recognizing each growth factor. Whereas HRP-3 protein is expressed only in brain, HDGF can be found in a broad range of tissues, with highest levels in brain, testis, lung and spleen. The expression of HDGF and HRP-3 was found to be regulated during brain development, with highest levels around birth, followed by a decline until postnatal day 9. Interestingly, expression of HRP-3 increases again in adult brain. In situ hybridization and immunohistochemistry of cerebellar, cerebral and hippocampal brain slices showed that expression of both growth factors is not limited to areas of high proliferative activity. Both mRNAs and proteins are expressed in neuronal as well as glial cells. Immunocytochemistry of cultured neocortical neurons revealed that HDGF and HRP-3 can be found in the nucleus as well as the cytoplasm. HDGF is restricted to the neuronal soma, whereas HRP-3 can also be found in neurites. Thus the expression of HDGF and HRP-3 in differentiated cells, post-mitotic neurons and primary cultures of rat neocortex points to functions in brain that might not be limited to proliferation. In addition, their simultaneous expression in the same cell and their different subcellular localization in cultured neurons suggest different functions of HDGF and HRP-3 within single cells.
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http://dx.doi.org/10.1042/BJ20030916DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1223924PMC
February 2004