Outlines:

A small population of K562 adhered to plastic dishes after 24 hours of incubation with tumor promoters such as PDBu (phorbol 12,13-dibutylate) or teleocidin. During this process, many blebs appear on the cell surface with in 10 minutes of PDBu addition and that these blebs disappeared spontaneously after 12 hours. Not only the tumor promoting activity but also PKC inhibitory activity can be assayed since the bleb formation was inhibited in the presence of the inhibitors of PKC. Bleb forming assay: K562 cells were seeded at a density of 1 x 104 cells per well into 96-multiwell plates, which were then incubated with/without 2uM of PDBu in the presence of test compounds. Cell morphology was observed under a microscope. Ten nM of staurosporine inhibited the bleb formation of K562 completely under these conditions.

(hours)	(a)	(b)	(c)
0
2
12
24
Microscopic observationof morphological changes. K562 (a), HL60 (b), and Friend leukemica cells (c) were treated with 1 uM of PDBu for indicated time. (Ref:1)

PBDu (●) and teleocidin B (○) were added to K562 at a concentration of 1 uM.(Ref:1)

References:

1. H. Osada, J. Magae, C. Watanabe, K. Isono.
   Rapid screening method for inhibitors of protein kinase C.
   J. Antibiot., 41, 925-931 (1988).