A 2-DIMENSIONAL MODEL OF CELL-MOVEMENT - WELL-DIFFERENTIATED HUMAN RECTAL ADENOCARCINOMA CELLS MOVE AS COHERENT SHEETS UPON TPA STIMULATION

We previously found that 12-O-tetradecanoylphorbol-13-acetate (TPA)-en hanced invasion of Matrigel was associated with augmentation of cell m otility but not with metalloproteinase activity in a highly metastatic variant (L-10) of human rectal adenocarcinoma cell line RCM-1. In the present study, with a two-dimensional cell motility assay, we investi gated morphology of TPA-induced motility and biochemical pathways that may be involved in the induction of such a motile response to TPA. TP A induced active cell locomotion in L-10 cells with characteristic mor phology: the cells moved outwards from the cell islands mainly as a lo calized coherent sheet of cells with few single moved out cells, but n ot cell proliferation. The front cells showed locomotor morphologies w ith front-tail polarity and well-spread leading lamella. Thus, this TP A-induced L-10 cell spreading and motility system seems to be a good m odel to investigate how well-differentiated adenocarcinoma cells move as cohesive cell nests. Agents which selectively modulate the adenylat e cyclase or G protein-related pathways, e.g., 2',5'-dideoxyadenosine and pertussis toxin, had negligible effect upon motility. In contrast, the membrane-permeable synthetic diacyl-glycerol 1-oleoyl-2-acetyl-gl ycerol, which has been reported to activate protein kinase C (PKC) dir ectly, could induce cell spreading and motility. Unexpectedly, PKC inh ibitors staurosporine and H-7 enhanced TPA-induced cell spreading and motility. Staurosporine itself could induce cell spreading and motilit y. Taken together, these observations suggested possible involvement o f PKC in TPA-induced L-10 cell spreading and motility and that stauros porine might have PKC agonist effect on induction of the spreading and motility.