Search results for: Mahmoud Toulany

Items from 1 to 20 out of 20 results

article

Cell-line dependent effects of hypoxia prior to irradiation in squamous cell carcinoma lines

Franziska Hauth, Mahmoud Toulany, Daniel Zips, Apostolos Menegakis

Clinical and Translational Radiation Oncology > 2017 > 5 > C > 12-19

To assess the impact of hypoxia exposure on cellular radiation sensitivity and survival of tumor cells with diverse intrinsic radiation sensitivity under normoxic conditions.Three squamous cell carcinoma (SCC) cell lines, with pronounced differences in radiation sensitivity, were exposed to hypoxia prior, during or post irradiation. Cells were seeded in parallel for colony formation assay (CFA) and...

article

Phosphatidylinositol 3-kinase/Akt signaling as a key mediator of tumor cell responsiveness to radiation

Mahmoud Toulany, H. Peter Rodemann

Seminars in Cancer Biology > 2015 > 35 > Complete > 180-190

The phosphatidylinositol 3-kinase (PI3K)/Akt pathway is a key cascade downstream of several protein kinases, especially membrane-bound receptor tyrosine kinases, including epidermal growth factor receptor (EGFR) family members. Hyperactivation of the PI3K/Akt pathway is correlated with tumor development, progression, poor prognosis, and resistance to cancer therapies, such as radiotherapy, in human...

article

AMPK-independent autophagy promotes radioresistance of human tumor cells under clinical relevant hypoxia in vitro

Hassan Chaachouay, Birgit Fehrenbacher, Mahmoud Toulany, Martin Schaller, more

Radiotherapy and Oncology > 2015 > 116 > 3 > 409-416

Blocking of the autophagy-signaling has the potential to improve cancer therapy. In the present study, the role of autophagy for radioresistance of human tumor cells was tested under clinically relevant hypoxia (1% O₂).Non-small cell lung cancer cell lines A549 and H460, head and neck squamous cell carcinoma FaDu, colon carcinoma cell line HCT116 and mouse-embryo-fibroblasts were analyzed under normoxic...

article

Cisplatin-mediated radiosensitization of non-small cell lung cancer cells is stimulated by ATM inhibition

Mahmoud Toulany, Julia Mihatsch, Marina Holler, Hassan Chaachouay, more

Radiotherapy and Oncology > 2014 > 111 > 2 > 228-236

Cisplatin activates ataxia-telangiectasia-mutated (ATM), a protein with roles in DNA repair, cell cycle progression and autophagy. We investigated the radiosensitizing effect of cisplatin with respect to its effect on ATM pathway activation.Non-small cell lung cancer cells (NSCLC) cell lines (A549, H460) and human fibroblast (ATM-deficient AT5, ATM-proficient 1BR3) cells were used. The effects of...

article

Acquired resistance to cetuximab is associated with the overexpression of Ras family members and the loss of radiosensitization in head and neck cancer cells

Mohammad Saki, Mahmoud Toulany, H. Peter Rodemann

Radiotherapy and Oncology > 2013 > 108 > 3 > 473-478

Cetuximab in combination with radiation therapy is used to treat patients with head and neck squamous cell carcinoma (HNSCC). In the present study, the mechanism of acquired resistance to cetuximab in HNSCC cells was investigated in vitro.The HNSCC cell lines UT5 and SAS and UT5 cells with acquired resistance to cetuximab (UT5R9) were used. The radiotoxicity potentials of cetuximab and inhibitors...

article

The impact of erythrocyte age on eryptosis

Mehrdad Ghashghaeinia, Judith C. A. Cluitmans, Ahmed Akel, Peter Dreischer, more

British Journal of Haematology > 157 > 5 > 606 - 614

Mature, circulating erythrocytes undergo senescence, which limits their life span to approximately 120 d. Upon injury, erythrocytes may undergo suicidal erythrocyte death or eryptosis, which may accelerate senescence and shorten their survival. Eryptosis is defined as cell shrinkage and exposure of phosphatidylserine at the cell surface. Triggers of eryptosis include oxidative stress. The present...

article

Roles of the NFκB and glutathione pathways in mature human erythrocytes

Mehrdad Ghashghaeinia, Mahmoud Toulany, Mohammad Saki, H. Peter Rodemann, more

Cellular & Molecular Biology Letters > 2012 > 17 > 1 > 11-20

Anucleated erythrocytes were long considered as oxygen-transporting cells with limited regulatory functions. Components of different nuclear signaling pathways have not been investigated in those cells, yet. Surprisingly, we repeatedly found significant amounts of transcription factors in purified erythrocyte preparations, i.e. nuclear factor κB (NFκB), and major components of the canonical NFκB signaling...

article

K-RAS(V12) Induces Autocrine Production of EGFR Ligands and Mediates Radioresistance Through EGFR-Dependent Akt Signaling and Activation of DNA-PKcs

Minjmaa Minjgee, Mahmoud Toulany, Rainer Kehlbach, Klaudia Giehl, more

International Journal of Radiation Oncology, Biology, Physics > 2011 > 81 > 5 > 1506-1514

It is known that postirradiation survival of tumor cells presenting mutated K-RAS is mediated through autocrine activation of epidermal growth factor receptor (EGFR). In this study the molecular mechanism of radioresistance of cells overexpressing mutated K-RAS(V12) was investigated.Head-and-neck cancer cells (FaDu) presenting wild-type K-RAS were transfected with empty vector or vector expressing...

article

Function of erbB receptors and DNA-PKcs on phosphorylation of cytoplasmic and nuclear Akt at S473 induced by erbB1 ligand and ionizing radiation

Mahmoud Toulany, Tim-Andre Schickfluß, Kazi R. Fattah, Kyung-Jong Lee, more

Radiotherapy and Oncology > 2011 > 101 > 1 > 140-146

In the present study effect of erbB2 as well as DNA-PKcs on ionizing radiation (IR)- and erbB1 ligand-induced phosphorylation of Akt at S473 in cytoplasmic and nuclear fractions was investigated.DNA-PKcs proficient and deficient syngeneic colon carcinoma sublines of HCT116 and the glioblastoma cell lines MO59K and MO59J as well as the lung carcinoma cell line A549 were used. Akt-S473 phosphorylation...

article

Autophagy contributes to resistance of tumor cells to ionizing radiation

Hassan Chaachouay, Petra Ohneseit, Mahmoud Toulany, Rainer Kehlbach, more

Radiotherapy and Oncology > 2011 > 99 > 3 > 287-292

Autophagy signaling is a novel important target to improve anticancer therapy. To study the role of autophagy on resistance of tumor cells to ionizing radiation (IR), breast cancer cell lines differing in their intrinsic radiosensitivity were used.Breast cancer cell lines MDA-MB-231 and HBL-100 were examined with respect to clonogenic cell survival and induction of autophagy after radiation exposure...

article

Selection of radioresistant tumor cells and presence of ALDH1 activity in vitro

Julia Mihatsch, Mahmoud Toulany, Petra M. Bareiss, Sabrina Grimm, more

Radiotherapy and Oncology > 2011 > 99 > 3 > 300-306

Tumor resistance to radiotherapy has been hypothesized to be mediated by a tumor subpopulation, called cancer stem cells (CSCs). Based on the proposed function of CSCs in radioresistance, we explored the cancer stem cell properties of cells selected for radioresistance phenotype.A549 and SK-BR-3 cells were radioselected with four single doses of 4 or 3Gy in intervals of 10–12days and used for colony...

article

Impact of oncogenic K-RASon YB-1 phosphorylation induced by ionizing radiation

Mahmoud Toulany, Tim-Andre Schickfluß, Wolfgang Eicheler, Rainer Kehlbach, more

Breast Cancer Research > 2011 > 13 > 2 > 1-14

Introduction Expression of Y-box binding protein-1 (YB-1) is associated with tumor progression and drug resistance. Phosphorylation of YB-1 at serine residue 102 (S102) in response to growth factors is required for its transcriptional activity and is thought to be regulated by cytoplasmic signaling phosphatidylinositol 3-kinase (PI3K)/Akt and mitogen-activated protein kinase/extracellular signal-regulated...

article

ErbB2 expression through heterodimerization with erbB1 is necessary for ionizing radiation- but not EGF-induced activation of Akt survival pathway

Mahmoud Toulany, Minjmaa Minjgee, Rainer Kehlbach, Jianyong Chen, more

Radiotherapy and Oncology > 2010 > 97 > 2 > 338-345

ErbB1-dependent Akt phosphorylation improves post-irradiation cellular survival. In the present study, we investigated the contribution of erbB2 as a heterodimerization partner of erbB1 in activation of Akt survival signaling after irradiation or EGF treatment.Pattern of receptor dimerization and protein phosphorylation were investigated by Western and immunoblotting as well as immunoprecipitation...

article

Radiocontrast media affect radiation-induced DNA damage repair in vitro and in vivo by affecting Akt signalling

Mahmoud Toulany, Rainer Kehlbach, H. Peter Rodemann, Hossein Mozdarani

Radiotherapy and Oncology > 2010 > 94 > 1 > 110-116

The study was performed to investigate cytogenetic effects of ionic and non-ionic radiocontrast media (RCM) meglumine, iohexol alone and in combination with irradiation in mouse bone marrow cells in vivo and in vitro.Micronuclei assay was performed in bone marrow cells (BMC) of Balb/C mice intraperitoneally injected with RCM in the presence or absence of whole-body irradiation of 50mGy. DNA repair...

article

Interplay of EGF receptor and DNA damage pathways

H. Peter Rodemann, Klaus Dittmann, Mahmoud Toulany, Minjmaa Minjgee

Toxicology Letters > 2009 > 189 > Supplement > S21-S22

article

2-Methoxyestradiol-induced radiosensitization is independent of SOD but depends on inhibition of Akt and DNA-PKcs activities

Urszula Florczak, Mahmoud Toulany, Rainer Kehlbach, H. Peter Rodemann

Radiotherapy and Oncology > 2009 > 92 > 3 > 334-338

2-Methoxyestradiol (2-ME) is described as an inhibitor of the superoxide dismutase (SOD) enzyme activity. However, it attenuates PI3K/Akt pathway and induces radiosensitization in human tumor cells as well. Since the activation of catalytic subunit of DNA-protein kinase (DNA-PKcs) is partially regulated by Akt activity, in the present study we investigated whether 2-ME-induced radiosensitization is...

article

PI3K-Akt signaling regulates basal, but MAP-kinase signaling regulates radiation-induced XRCC1 expression in human tumor cells in vitro

Mahmoud Toulany, Klaus Dittmann, Birgit Fehrenbacher, Martin Schaller, more

DNA Repair > 2008 > 7 > 10 > 1746-1756

As demonstrated recently, ionizing radiation (IR) can mediate phosphorylation of DNA-PKcs in human tumor cells through stimulation of the PI3K/Akt pathway. It is also known that DNA-PKcs directly interacts the X-ray repair cross-complementing group 1 protein (XRCC1) involved in base excision repair (BER). Therefore, in the present study we investigated the role of PI3K/Akt activity and DNA-PKcs on...

article

Radioresistance of K-Ras mutated human tumor cells is mediated through EGFR-dependent activation of PI3K-AKT pathway

Mahmoud Toulany, Klaus Dittmann, Maren Krüger, Michael Baumann, more

Radiotherapy and Oncology > 2005 > 76 > 2 > 143-150

In the context of EGFR-targeting strategies we investigated autocrine/paracrine factors leading to in vitro radioresistance of K-Ras mutated tumor cells through activation of EGFR mediated signal transduction.Ras mutated (Ras _mt ) and normal Ras (Ras _wt ) presenting human tumor cell lines were used to analyze the potential of conditioned media (CM) of both cell types to mediate radioresistance...

article

Radiosensitization of Ras-mutated human tumor cells in vitro by the specific EGF receptor antagonist BIBX1382BS

Mahmoud Toulany, Klaus Dittmann, Michael Baumann, H. Peter Rodemann

Radiotherapy and Oncology > 2005 > 74 > 2 > 117-129

To investigate the cellular and molecular consequences of antagonizing radiation-induced EGFR-activation in vitro.The effect of the EGFR tyrosine kinase inhibitor BIBX1382BS on radiation sensitivity was determined after single- and fractionated-dose irradiation in human cell lines of bronchial carcinoma (A549), breast adeno-carcinoma (MDA-MB-231), pharyngeal squamous-cell carcinoma (FaDu), squamous-cell...

article

Selective Radioprotection of Normal Tissues by Bowman-Birk Proteinase Inhibitor (BBI) in Mice

Klaus Dittmann, Mahmoud Toulany, Johannes Classen, Vanessa Heinrich, more

Strahlentherapie und Onkologie > 2005 > 181 > 3 > 191-196

Background and Purpose: The efficacy of radiotherapy is limited by the response of normal tissues within the radiation field. The application of normal-tissue-specific radioprotectors may improve the therapeutic benefit of radiotherapy. The purpose of the present study was to explore the in vivo normal-tissue radioprotective potential of Bowman-Birk proteinase inhibitor (BBI), which acts as a normal-cell-specific...

Filter options

Publication date

Set your own date range

INFONA - science communication portal

Search results for: Mahmoud Toulany

Add recipient

Sending message cancelled

Are you sure you want to cancel sending this message?

Send message

Filter options

Publication date

Date range setting

Set the date range to filter the displayed results. You can set a starting date, ending date or both. You can enter the dates manually or choose them from the calendar.

Content availability

Keywords

Data set

Journal

Reporting an error / abuse

Sending the report failed

Accessibility options