Effects of CD44 Ligation on Signaling and Metabolic Pathways in Acute Myeloid Leukemia

Handle URI:
http://hdl.handle.net/10754/623479
Title:
Effects of CD44 Ligation on Signaling and Metabolic Pathways in Acute Myeloid Leukemia
Authors:
Madhoun, Nour Y. ( 0000-0003-0056-3172 )
Abstract:
Acute myeloid leukemia (AML) is characterized by a blockage in the differentiation of myeloid cells at different stages. CD44-ligation using anti-CD44 monoclonal antibodies (mAbs) has been shown to reverse the blockage of differentiation and to inhibit the proliferation of blasts in most AML-subtypes. However, the molecular mechanisms underlying this property have not been fully elucidated. Here, we sought to I) analyze the effects of anti-CD44 mAbs on downstream signaling pathways, including the ERK1/2 (extracellular signal-regulated kinase 1 and 2) and mTOR (mammalian target of rapamycin) pathways and II) use state-of-the-art Nuclear Magnetic Resonance (NMR) technology to determine the global metabolic changes during differentiation induction of AML cells using anti-CD44 mAbs and other two previously reported differentiation agents. In the first objective (Chapter 4), our studies provide evidence that CD44-ligation with specific mAbs in AML cells induced an increase in ERK1/2 phosphorylation. The use of the MEK inhibitor (U0126) significantly inhibited the CD44-induced differentiation of HL60 cells, suggesting that ERK1/2 is critical for the CD44-triggered differentiation in AML. In addition, this was accompanied by a marked decrease in the phosphorylation of the mTORC1 and mTORC2 complexes, which are strongly correlated with the inhibition of the PI3K/Akt pathway. In the second objective (Chapter 5), 1H NMR experiments demonstrated that considerable changes in the metabolic profiles of HL60 cells were induced in response to each differentiation agent. These most notable metabolites that significantly changed upon CD44 ligation were involved in the tricarboxylic acid (TCA) cycle and glycolysis such as, succinate, fumarate and lactate. Therefore, we sought to analyze the mechanisms underlying their alterations. Our results revealed that anti-CD44 mAbs treatment induced upregulation in fumarate hydratase (FH) expression and its activity which was accompanied by a decrease in succinate dehydrogenase (SDH) activity. Interestingly, our results indicated that FH induced by anti-CD44 mAb is regulated through the activation of the ERK1/2 pathway. Therefore, our findings highlight new elements in support for the use of anti-CD44 mAbs in AML therapies and open new perspectives to use metabolic profiling as a tool to support the potential possibilities for the development of CD44-targeted therapy of AML.
Advisors:
Merzaban, Jasmeen ( 0000-0002-7276-2907 )
Committee Member:
Arold, Stefan T. ( 0000-0001-5278-0668 ) ; Kosel, Jürgen ( 0000-0002-8998-8275 ) ; Johnson, Pauline
KAUST Department:
Biological and Environmental Sciences and Engineering (BESE) Division
Program:
Bioscience
Issue Date:
Apr-2017
Type:
Dissertation
Appears in Collections:
Dissertations

Full metadata record

DC FieldValue Language
dc.contributor.advisorMerzaban, Jasmeenen
dc.contributor.authorMadhoun, Nour Y.en
dc.date.accessioned2017-05-14T05:49:39Z-
dc.date.available2017-05-14T05:49:39Z-
dc.date.issued2017-04-
dc.identifier.urihttp://hdl.handle.net/10754/623479-
dc.description.abstractAcute myeloid leukemia (AML) is characterized by a blockage in the differentiation of myeloid cells at different stages. CD44-ligation using anti-CD44 monoclonal antibodies (mAbs) has been shown to reverse the blockage of differentiation and to inhibit the proliferation of blasts in most AML-subtypes. However, the molecular mechanisms underlying this property have not been fully elucidated. Here, we sought to I) analyze the effects of anti-CD44 mAbs on downstream signaling pathways, including the ERK1/2 (extracellular signal-regulated kinase 1 and 2) and mTOR (mammalian target of rapamycin) pathways and II) use state-of-the-art Nuclear Magnetic Resonance (NMR) technology to determine the global metabolic changes during differentiation induction of AML cells using anti-CD44 mAbs and other two previously reported differentiation agents. In the first objective (Chapter 4), our studies provide evidence that CD44-ligation with specific mAbs in AML cells induced an increase in ERK1/2 phosphorylation. The use of the MEK inhibitor (U0126) significantly inhibited the CD44-induced differentiation of HL60 cells, suggesting that ERK1/2 is critical for the CD44-triggered differentiation in AML. In addition, this was accompanied by a marked decrease in the phosphorylation of the mTORC1 and mTORC2 complexes, which are strongly correlated with the inhibition of the PI3K/Akt pathway. In the second objective (Chapter 5), 1H NMR experiments demonstrated that considerable changes in the metabolic profiles of HL60 cells were induced in response to each differentiation agent. These most notable metabolites that significantly changed upon CD44 ligation were involved in the tricarboxylic acid (TCA) cycle and glycolysis such as, succinate, fumarate and lactate. Therefore, we sought to analyze the mechanisms underlying their alterations. Our results revealed that anti-CD44 mAbs treatment induced upregulation in fumarate hydratase (FH) expression and its activity which was accompanied by a decrease in succinate dehydrogenase (SDH) activity. Interestingly, our results indicated that FH induced by anti-CD44 mAb is regulated through the activation of the ERK1/2 pathway. Therefore, our findings highlight new elements in support for the use of anti-CD44 mAbs in AML therapies and open new perspectives to use metabolic profiling as a tool to support the potential possibilities for the development of CD44-targeted therapy of AML.en
dc.language.isoenen
dc.subjectCD44en
dc.subjectMetabolomicsen
dc.subjectAcute Myeloid Leukemiaen
dc.subjectSignalingen
dc.titleEffects of CD44 Ligation on Signaling and Metabolic Pathways in Acute Myeloid Leukemiaen
dc.typeDissertationen
dc.contributor.departmentBiological and Environmental Sciences and Engineering (BESE) Divisionen
thesis.degree.grantorKing Abdullah University of Science and Technologyen_GB
dc.contributor.committeememberArold, Stefan T.en
dc.contributor.committeememberKosel, Jürgenen
dc.contributor.committeememberJohnson, Paulineen
thesis.degree.disciplineBioscienceen
thesis.degree.nameDoctor of Philosophyen
dc.person.id101722en
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