Inhibition of protein kinase C delta has negative effect on anchorage-independent growth of BCR-ABL-transformed Rat1 cells

The BCR-ABL oncoprotein transmits transformation signals mainly through pat hways involving Ras. Myc and P13 kinase. Here we report that inhibition of protein kinase C (PKC) delta had negative influence on anchorage-independen t growth of Rat1 cells transformed by BCR-ABL. The effect was observed with delta isoform-specific inhibitor rottlerin. but not with Go6976 that inhib its only conventional isoforms. The kinase activity of delta isoform was fo und to be roughly two-fold higher in BCR-ABL-expressing Rat1 cells than tha t in mock, Although overexpression of wild type PKC delta did not enhance s oft agar colony number by BCR-ABL-transformed Rat1 cells, that of dominant- negative delta isoform reduced it by approximately 40%. (C) 2001 Elsevier S cience Ltd. All rights reserved.