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Cellular interactions of HAMLET and their role in cell death

Trulsson, Maria LU (2011) In Lund Unviersity, Faculty of Medicine Doctoral Dissertation Series 2011:96.
Abstract
HAMLET is a protein-lipid complex that selectively kills tumor cells. In this thesis, we identified new mechanisms, whereby HAMLET initiates and executes tumor cell death. HAMLET targets several cellular compartments ranging from the plasma membrane to the nucleus. HAMLET rapidly binds to the plasma membrane of tumor cells and the resulting changes in membrane shape and lipid composition activate ion channels and rapid ion fluxes (paper I). Through macropinocytosis, large amounts of HAMLET enter tumor cells, thus reaching intracellular targets (paper II). By interacting with alpha-actinins, HAMLET facilitates tumor cell detachment and perturbs FAK signaling (paper III). Furthermore, HAMLET interacts with HK1, a member of the glycolytic... (More)
HAMLET is a protein-lipid complex that selectively kills tumor cells. In this thesis, we identified new mechanisms, whereby HAMLET initiates and executes tumor cell death. HAMLET targets several cellular compartments ranging from the plasma membrane to the nucleus. HAMLET rapidly binds to the plasma membrane of tumor cells and the resulting changes in membrane shape and lipid composition activate ion channels and rapid ion fluxes (paper I). Through macropinocytosis, large amounts of HAMLET enter tumor cells, thus reaching intracellular targets (paper II). By interacting with alpha-actinins, HAMLET facilitates tumor cell detachment and perturbs FAK signaling (paper III). Furthermore, HAMLET interacts with HK1, a member of the glycolytic machinery, and thereby disrupts tumor cell metabolism (paper IV). HAMLET also triggers ER stress (paper I).



This provides a framework for HAMLET’s ability to rapidly kill a wide range of tumor cells and addresses three major HAMLET questions. 1. How are the tumor cells killed? 2. How is HAMLET internalized by tumor cells? 3. Why do normal differentiated cells survive? We show that HAMLET-induced cell death is initiated at the plasma membrane and requires functional ion channels and p38 MAPK signaling. We identify macropinocytosis as a route for HAMLET internalization and distinguish this process from cell death. Finally, we show that the HAMLET sensitivity reflects tumor cell characteristics, such as c-Myc oncogene expression and altered metabolism, as inhibition of glycolysis increased HAMLET sensitivity. Interestingly, HAMLET does not appear to perturb the membranes of normal differentiated cells, further explaining the tumor selectivity. (Less)
Please use this url to cite or link to this publication:
author
supervisor
opponent
  • Qasba, Pradman K, Center for Cancer Research, National Cancer Institute, NIH, USA
organization
publishing date
type
Thesis
publication status
published
subject
keywords
HAMLET, alpha-lactalbumin, cancer, cell death, ion channels, p38, cell detachment, alpha-actinin, endocytosis, macropinocytosis, c-Myc, glycolysis
in
Lund Unviersity, Faculty of Medicine Doctoral Dissertation Series
volume
2011:96
pages
198 pages
publisher
Department of Microbiology, Immunology and Glycobiology, Lund University
defense location
Segerfalksalen, Wallenberg Neurocentrum, BMC, Lund
defense date
2011-11-18 09:00
ISSN
1652-8220
ISBN
978-91-86871-45-1
language
English
LU publication?
yes
id
a632e3a8-6936-4758-a92b-cf9bc55fd123 (old id 2199760)
date added to LUP
2011-11-01 10:57:51
date last changed
2016-09-19 08:44:45
@phdthesis{a632e3a8-6936-4758-a92b-cf9bc55fd123,
  abstract     = {HAMLET is a protein-lipid complex that selectively kills tumor cells. In this thesis, we identified new mechanisms, whereby HAMLET initiates and executes tumor cell death. HAMLET targets several cellular compartments ranging from the plasma membrane to the nucleus. HAMLET rapidly binds to the plasma membrane of tumor cells and the resulting changes in membrane shape and lipid composition activate ion channels and rapid ion fluxes (paper I). Through macropinocytosis, large amounts of HAMLET enter tumor cells, thus reaching intracellular targets (paper II). By interacting with alpha-actinins, HAMLET facilitates tumor cell detachment and perturbs FAK signaling (paper III). Furthermore, HAMLET interacts with HK1, a member of the glycolytic machinery, and thereby disrupts tumor cell metabolism (paper IV). HAMLET also triggers ER stress (paper I). <br/><br>
<br/><br>
This provides a framework for HAMLET’s ability to rapidly kill a wide range of tumor cells and addresses three major HAMLET questions. 1. How are the tumor cells killed? 2. How is HAMLET internalized by tumor cells? 3. Why do normal differentiated cells survive? We show that HAMLET-induced cell death is initiated at the plasma membrane and requires functional ion channels and p38 MAPK signaling. We identify macropinocytosis as a route for HAMLET internalization and distinguish this process from cell death. Finally, we show that the HAMLET sensitivity reflects tumor cell characteristics, such as c-Myc oncogene expression and altered metabolism, as inhibition of glycolysis increased HAMLET sensitivity. Interestingly, HAMLET does not appear to perturb the membranes of normal differentiated cells, further explaining the tumor selectivity.},
  author       = {Trulsson, Maria},
  isbn         = {978-91-86871-45-1},
  issn         = {1652-8220},
  keyword      = {HAMLET,alpha-lactalbumin,cancer,cell death,ion channels,p38,cell detachment,alpha-actinin,endocytosis,macropinocytosis,c-Myc,glycolysis},
  language     = {eng},
  pages        = {198},
  publisher    = {Department of Microbiology, Immunology and Glycobiology, Lund University},
  school       = {Lund University},
  series       = {Lund Unviersity, Faculty of Medicine Doctoral Dissertation Series},
  title        = {Cellular interactions of HAMLET and their role in cell death},
  volume       = {2011:96},
  year         = {2011},
}