Modulation of alpha-actinin levels affects cell motility and confers tumorigenicity on 3T3 cells.
alpha-Actinin is an abundant actin crosslinking protein, also localized at adherens type junctions. In adhesion plaques, alpha-actinin can link the actin filaments to integrin via vinculin and talin, or directly by binding to the cytoplasmic domain of beta 1-integrin. The expression of alpha-actinin is rapidly elevated in growth-activated quiescent cells, and is reduced in SV40-transformed 3T3 cells and various differentiating cell types (reviewed by Glück, U., Kwiatkowski, D. J. and Ben-Ze'ev, A. Proc. Nat. Acad. Sci. USA 90, 383-387, 1993). To study the effect of changes in alpha-actinin levels on cell behavior, alpha-actinin expression was elevated in 3T3 cells by transfection with a full-length human nonmuscle alpha-actinin cDNA. To suppress alpha-actinin levels, 3T3 cells were transfected with an antisense alpha-actinin cDNA construct. Cells overexpressing alpha-actinin by 40-60% displayed a significant reduction in cell motility, as demonstrated by their slower locomotion into an artificial wound, and by forming shorter phagokinetic tracks on colloidal gold-coated substrata. 3T3 cells in which the expression of alpha-actinin was reduced to 25-60% of control levels, after antisense alpha-actinin transfection, had an increased cell motility. Moreover, such alpha-actinin-deficient 3T3 cells formed tumors upon injection into nude mice. The results demonstrate that modulations in alpha-actinin expression can affect, in a major way, the motile and tumorigenic properties of cells, and support the view that decreased alpha-actinin expression could be a common regulatory pathway to malignant transformation of 3T3 cells.
Glück
U
U
Department of Molecular Genetics and Virology, Weizmann Institute of Science, Rehovot, Israel.
Ben-Ze'ev
A
A
D016475:3T3 Cells; D000185:Actinin / Q000032:analysis / Q000096:biosynthesis* / Q000302:isolation & purification; D000818:Animals; D002465:Cell Movement; D002471:Cell Transformation, Neoplastic; D018076:DNA, Complementary / Q000378:metabolism; D004591:Electrophoresis, Polyacrylamide Gel; D005822:Genetic Vectors; D006801:Humans; D051379:Mice; D008819:Mice, Nude; D009374:Neoplasms, Experimental / Q000473:pathology; D015183:Restriction Mapping; D013539:Simian virus 40; D014162:Transfection
D018076:DNA, Complementary; D000185:Actinin