|
Mohri T, Kameshita I, Suzuki S, Hioki K, Tokunaga R, Takatani S.
Rapid adhesion and spread of non-adherent colon cancer Colo201 cells induced
by the protein kinase inhibitors, K252a and KT5720 and suppression of the
adhesion by the immunosuppressants FK506 and cyclosporin A.
Cell Struct Funct. 1998 Oct;23(5):255-64.
Second Department of Surgery, Kansai Medical University,
Moriguchi, Osaka, Japan
We examined alterations in cell morphology and expression of
adhesion molecules in response to a general protein kinase
inhibitor K252a treatment of non-adherent colon adenocarcinoma
Colo201 cells. K252a induced rapid cell adhesion and spreading
with concomitant formation of actin stress fibers. A protein
kinase A inhibitor KT5720 also induced cell adhesion, but the
rate of spread was slower than that seen with K252a. These
adhesions were mediated by integrin molecules since cell
adhesion required Mg2+, Mn2+ or Ca2+, and was inhibited by
monoclonal antibodies for integrins alpha2 and beta1. Indirect
immunofluorescence microscopic observations revealed that
integrin alpha2 and beta1 molecules in K252a-treated cells were
concentrated at sites of focal adhesion, but expressions of
integrin molecules were not modulated. Tyrosine phosphorylation
of focal adhesion kinase (FAK) and paxillin increased during
K252a- or KT5720-induced cell adhesion. Immunosuppressants FK506
and cyclosporin A suppressed the K252a-induced cell adhesion and
abolished tyrosine phosphorylation of cellular proteins
including FAK and paxillin. Furthermore, W7 and calmidazolium,
inhibitors of calmodulin, also inhibited the cell adhesion.
Based on findings that FK506 and cyclosporin A are inhibitors of
the calcium calmodulin-dependent protein phosphatase,
calcineurin, this phosphatase may regulate integrin-dependent
cell adhesion and spread of Colo201 cells. This Colo201 cell
model provides a pertinent system for studying molecules
involved in signal transduction pathways and can shed light on
mechanisms of metastasis and invasion of colon carcinoma cells
PMID: 9872566 |
