Propofol-induced calcium signalling and actin reorganization within breast carcinoma cells.
OBJECTIVE
MDA-MB-468 breast carcinoma cells respond to non-volatile anaesthetics such as propofol with an increased migration. Here we investigated the relationship between GABA-A receptor modulators, the mode of calcium oscillation and actin reorganization with regard to breast carcinoma cell migration.


METHODS
Expression of the GABA-A receptor was determined by Western blot analysis. Calcium-imaging experiments of individual MDA-MB-468 cells as well as visualization of the F-actin distribution were performed by confocal laser scanning microscopy. Cell migration was investigated in a three-dimensional collagen matrix by time-lapse video microscopy. The GABA agonist propofol was used in a final concentration of 6 microg mL(-1). GABA-A receptor antagonist bicuculline (50 micromol) and selective L-type calcium channel blocker verapamil (5 micromol) were used to modulate the propofol effects.


RESULTS
A functional GABA-A receptor is expressed by MDA-MB-468 cells. Activation with propofol resulted in sustained increased intracellular calcium concentrations concomitant with actin reorganization and induction of migration in MDA-MB-468 cells. These propofol effects were completely blocked by verapamil. Spontaneous migration of MDA-MB-468 cells (64.4 +/- 7.0%) was significantly increased by propofol to 85.0 +/- 5.0%. MDA-MB-468 cells co-treated with propofol and verapamil showed a migratory activity of 63.0 +/- 2.0% indicating that verapamil blocked the propofol effect. Similar results were achieved with the GABA-A receptor inhibitor bicuculline (control: 56.3 +/- 8.5%; propofol: 80.5 +/- 7.1%; propofol + bicuculline: 52.5 +/- 8.6%).


CONCLUSIONS
Activation of GABA-A receptor by propofol correlated with an increased migration of MDA-MB-468 breast carcinoma cells, mediated by calcium influx via L-type calcium channels and reorganization of the actin cytoskeleton.
Garib
V
V
University of Witten/Herdecke, Institute of Immunology, Witten, Germany.
Lang
K
K
Niggemann
B
B
Zänker
K S
KS
Brandt
L
L
Dittmar
T
T
D000199:Actins / Q000378:metabolism*; D018686:Anesthetics, Intravenous / Q000494:pharmacology*; D015153:Blotting, Western; D001943:Breast Neoplasms / Q000378:metabolism / Q000503:physiopathology*; D002121:Calcium Channel Blockers / Q000494:pharmacology; D020746:Calcium Channels, L-Type / Q000187:drug effects; D020013:Calcium Signaling / Q000187:drug effects*; D045744:Cell Line, Tumor; D002465:Cell Movement / Q000187:drug effects; D003599:Cytoskeleton / Q000187:drug effects; D005260:Female; D006801:Humans; D018613:Microscopy, Confocal; D015742:Propofol / Q000494:pharmacology*; D011963:Receptors, GABA-A / Q000187:drug effects; D014700:Verapamil / Q000494:pharmacology
D000199:Actins; D018686:Anesthetics, Intravenous; D002121:Calcium Channel Blockers; D020746:Calcium Channels, L-Type; D011963:Receptors, GABA-A; D014700:Verapamil; D015742:Propofol