Constitutive insulin-like growth factor-II expression interferes with the enterocyte-like differentiation of CaCo-2 cells.
In this study we have examined the role of insulin-like growth factor-II (IGF-II) in the differentiation of the CaCo-2 human colon carcinoma cell line. We have shown previously that IGF-II is an autocrine growth factor for CaCo-2 cells. IGF-II expression is high in proliferating, undifferentiated CaCo-2 cells and markedly decreases when cells become confluent and start to differentiate. To evaluate whether differentiation of CaCo-2 cells depends on an IGF-II related pathway, we treated cells with a blocking antibody to the IGF-I receptor that mediates most IGF-II biological effects. Treatment of preconfluent CaCo-2 cells with this antibody decreased by 40% autonomous cell proliferation and induced differentiation as shown by an increase in sucrase isomaltase activity and apolipoprotein A-I (apoA-I) mRNA levels. To examine the significance of autocrine IGF-II production in CaCo-2 cell differentiation, we generated stable CaCo-2 cell lines that constitutively express rat IGF-II under the control of a Rous sarcoma virus promoter. Sustained expression of IGF-II resulted in: (a) increased proliferative rate; (b) high IGF-I receptor number, even after reaching confluence; (c) increased capability of anchorage-independent growth; (d) inhibition of the expression of apoA-I and SI mRNAs. Analysis of several independent IGF-II-transfected clones showed an inverse correlation between IGF-II mRNA levels and expression of the differentiation markers, the cells expressing the higher levels of the transfected IGF-II being the less differentiated ones. Our data suggest that perturbation of IGF-II-mediated cell proliferation interferes with the enterocyte-like differentiation pathway of CaCo-2 cells.
Zarrilli
R
R
Centro di Endocrinologia ed Oncologia Sperimentale del CNR, Università "Federico II," 80131 Napoli, Italy.
Romano
M
M
Pignata
S
S
Casola
S
S
Bruni
C B
CB
Acquaviva
A M
AM
D016632:Apolipoprotein A-I / Q000378:metabolism; D018938:Caco-2 Cells; D002448:Cell Adhesion; D002454:Cell Differentiation; D002455:Cell Division; D015870:Gene Expression; D006801:Humans; D007335:Insulin-Like Growth Factor II / Q000502:physiology*; D007413:Intestinal Mucosa / Q000166:cytology*; D012333:RNA, Messenger / Q000235:genetics; D017526:Receptor, IGF Type 1 / Q000502:physiology; D013394:Sucrase-Isomaltase Complex / Q000378:metabolism
D016632:Apolipoprotein A-I; D012333:RNA, Messenger; D007335:Insulin-Like Growth Factor II; D017526:Receptor, IGF Type 1; D013394:Sucrase-Isomaltase Complex