Effect of extracellular matrix on adhesion, viability, actin cytoskeleton and K+ currents of cells expressing human ether à go-go channels.
Ether à go-go (EAG) potassium channels possess oncogenic properties and have gained great interest as research tools for cancer detection and therapy. Besides, EAG electrophysiological properties are regulated through the cell cycle and determined by cytoskeletal interactions. Thus, because of the pivotal role of extracellular matrix (ECM) and cytoskeleton in cancer progression, we studied the effect of ECM components on adhesion, viability, actin organization and EAG currents in wild-type CHO cells (CHO-wt) and cells expressing human EAG channels (CHO-hEAG). At short incubation times, adhesion and viability of CHO-hEAG cells grown on collagen, heparin or poly-lysine were lower than CHO-wt cells, however, only CHO-hEAG sustained growing under total serum starvation. CHO-hEAG cells grown on poly-lysine did not organize their cytoskeleton but when grown on collagen or fibronectin displayed lamellipodia and stress fibers, respectively. Interestingly, EAG expressing cells displayed special actin structures suggesting a dynamic actin cytoskeleton, such structures were not exhibited by wild-type cells. EAG current density was significantly lower in cells grown on collagen at short incubation times. Finally, we studied potential associations between hEAG channels and integrins or actin filaments by confocal microscopy. No association between beta1-integrins and hEAG channels was found, however, a very strong co-localization was observed between hEAG channels and actin filaments, supported by immunoblot experiments in which hEAG channels were found in the insoluble fraction (associated to cytoskeleton). Our results suggest ECM components as potential modulators of oncogenic human-EAG expressing cells and emphasize the relationship between potassium channels, cytoskeleton, ECM and cancer.
Toral
Claudia
C
Pharmacology Section, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, Mexico City, Mexico.
Mendoza-Garrido
M Eugenia
ME
Azorín
Erika
E
Hernández-Gallegos
Elizabeth
E
Gomora
Juan Carlos
JC
Delgadillo
Dulce María
DM
Solano-Agama
Carmen
C
Camacho
Javier
J
D000199:Actins / Q000096:biosynthesis*; D000818:Animals; D016466:CHO Cells; D002448:Cell Adhesion / Q000502:physiology*; D049109:Cell Proliferation; D002470:Cell Survival / Q000502:physiology; D006224:Cricetinae; D003412:Cricetulus; D003599:Cytoskeleton / Q000378:metabolism*; D004594:Electrophysiology; D051638:Ether-A-Go-Go Potassium Channels / Q000096:biosynthesis* / Q000235:genetics; D005109:Extracellular Matrix / Q000502:physiology*; D005455:Fluorescent Antibody Technique; D017930:Genes, Reporter; D049452:Green Fluorescent Proteins / Q000096:biosynthesis; D006801:Humans; D007150:Immunohistochemistry; D039641:Integrin beta Chains / Q000096:biosynthesis; D018613:Microscopy, Confocal; D018408:Patch-Clamp Techniques; D014162:Transfection
D000199:Actins; D051638:Ether-A-Go-Go Potassium Channels; D039641:Integrin beta Chains; D049452:Green Fluorescent Proteins