The Kv10.1 voltage gated potassium ion channel modulates the cell adhesion and cell migration hallmarks of cancer

by Ioannis Alexopoulos
Doctoral thesis
Date of Examination:2015-06-15
Date of issue:2015-06-23
Advisor:Prof. Dr. Walter Stühmer
Referee:Prof. Dr. Walter Stühmer
Referee:Dr. Dieter Klopfenstein
Referee:Dr. Luis A. Pardo
Referee:Prof. Dr. Frauke Alves
Referee:Prof. Dr. Mikael Simons
Referee:Prof. Dr. Matthias Dobbelstein
Persistent Address: http://dx.doi.org/10.53846/goediss-5147

 

 

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Abstract

English

A characteristic of the Kv10.1 voltage-gated potassium ion channel is its overexpression in a number of cancerous tissues and cancer cell lines, even though it should normally be restricted to the adult brain and myoblasts. This compelled us to investigate the role this ion channel may play in cancer, where we initially localized it in filopodia, lamellipodial regions and at cell-cell or cell-surface adhesion interfaces, all of which are important for cell migration, a hallmark of cancer. Therefore, to further study how Kv10.1 affects cell motility and adhesion, we generated two HT-1080 cell lines stably overexpressing either Kv10.1-mVenus or only mVenus, both of which were then tasked to migrate induced by means of the scratch assay. However, cell behavior may be affected by the recording method used. We therefore conducted a methodological survey of a number of previously undescribed image acquisition scenarios, which enabled us to identify hardware settings with the least influence on cell behavior. Semi-automated, live-cell microscopy and image analysis revealed then that Kv10.1 overexpression lead to faster scratch-closure speeds with an accompanying loss of cell-cell adhesion, when compared to the control. Individual cell tracking showed that Kv10.1 overexpression enabled HT-1080 cells to migrate at a faster maximum speed, but along a less directed, longer and more complex path, given the same timespan. Additional experiments using interference reflection microscopy and a novel quantification algorithm, enabled us to detect cell-surface adhesion deficits due to Kv10.1 overexpression, which are present in stationary cells and likely cause the less coordinated, more invasive and faster migration with more degrees of freedom. We confirmed Kv10.1 overexpression to be the cause of the aberrant cell behavioral effects by the use of Kv10.1-specific antibody mAb56, as well as the antihistaminic drug astemizole. The results of this study indicate that the hallmarks of reduced cell adhesion and increased cell migration in cancer may depend on the abnormal Kv10.1 expression, the understanding of which may yield new diagnostic and treatment targets.
Keywords: migration; adhesion; cancer; IRM; scratch; eag1; Kv10.1; laser effect
Schlagwörter: migration; adhesion; cancer; IRM; scratch; eag1; Kv10.1; laser effect
 
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