Effect of extracellular matrix on adhesion, viability, actin cytoskeleton and K+ currents of cells expressing human
Claudia Toral1, M Eugenia Mendoza-Garrido, Erika Azorín
1Pharmacology Section, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, Mexico City, Mexico.
Abstract:
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.
Insights
Extracellular matrix components affect cancer-promoting Ether à go-go (EAG) potassium channels. EAG channels interact with the actin cytoskeleton, influencing cell behavior and potentially cancer progression.
Area of Science:
- Cell Biology
- Molecular Biology
- Biophysics
Background:
- Ether à go-go (EAG) potassium channels exhibit oncogenic properties, making them significant for cancer research.
- EAG channel function is influenced by cell cycle regulation and cytoskeletal interactions.
- The extracellular matrix (ECM) and cytoskeleton play crucial roles in cancer development.
Purpose of the Study:
- To investigate the impact of ECM components on cell adhesion, viability, actin organization, and EAG currents.
- To compare wild-type Chinese Hamster Ovary (CHO-wt) cells with those expressing human EAG channels (CHO-hEAG).
- To explore the association between hEAG channels, integrins, and actin filaments.
Main Methods:
- Cell culture of CHO-wt and CHO-hEAG cells on various ECM substrates (collagen, heparin, poly-lysine, fibronectin).
- Assessment of cell adhesion, viability, and actin cytoskeleton organization using microscopy.
- Measurement of EAG currents using electrophysiology.
- Confocal microscopy and immunoblotting to determine protein localization and interactions.
Main Results:
- CHO-hEAG cells showed reduced adhesion and viability on certain ECMs but survived serum starvation.
- Distinct actin organization patterns were observed in CHO-hEAG cells on different ECMs, indicating a dynamic cytoskeleton.
- EAG current density decreased on collagen at early time points.
- Strong co-localization of hEAG channels with actin filaments was confirmed, with channels found in the cytoskeleton-associated insoluble fraction.
Conclusions:
- ECM components modulate the behavior of oncogenic EAG-expressing cells.
- A significant relationship exists between potassium channels, the cytoskeleton, ECM, and cancer progression.
- hEAG channels are associated with the actin cytoskeleton, suggesting a role in cellular mechanics relevant to cancer.
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