Insulin-like growth factors I and II induce cell death in Wilms's tumour cells.
OBJECTIVE
To study the effects of insulin-like growth factors (IGFs) on the growth phenotype of a Wilms's tumour cell line (WCCS-1).


METHODS
WCCS-1 cells were cultured in vitro and exposed to IGF-I and IGF-II, as well as their antagonists, IGF binding protein 2 and the type I receptor blocking antibody IGF-IRalpha. The effects on proliferation and cell cycle parameters were assayed by assessing cell numbers, autoradiography after labelling with tritiated thymidine, and flow cytometry after double staining with fluorescein isothiocyanate (FITC) labelled annexin V and propidium iodide.


RESULTS
The addition of IGF-I as well as IGF-II in physiological doses induced cell death in Wilms's tumour cells. Cell numbers decreased most dramatically on the fifth to sixth day after growth factor addition. The occurrence of apoptosis as well as necrosis was confirmed by annexin-V staining of cell cultures. S-phase indices were comparable, irrespective of whether the cells were exposed to IGFs or not, which suggests that WCCS-1 cells undergo cell death at random during the cell cycle rather that from the prereplicative phase. To exclude any influences of the IGF binding proteins (IGFBPs), all results were repeated with Des(1-3)IGF-I, which is unable to bind to any of the IGFBPs. However, this peptide was equally potent in inducing cell death. Finally, the addition of IGFBP-2 or the type 1 receptor blocking antibody IGF-IRalpha partly abrogated the death inducing effects of IGF-I and IGF-II.


CONCLUSIONS
Insulin like growth factors induce cell death--apoptosis as well as necrosis--in cultured Wilms's tumour cells. Furthermore, it is proposed that this effect is mediated by the type 1 receptor.
Granérus
M
M
Department of Pathology, Faculty of Veterinary Medicine, Swedish University of Agricultural Sciences, Uppsala.
Johannisson
A
A
Ekblom
P
P
Engström
W
W
D017209:Apoptosis / Q000187:drug effects; D016923:Cell Death / Q000187:drug effects; D002455:Cell Division / Q000187:drug effects; D005434:Flow Cytometry; D006801:Humans; D007334:Insulin-Like Growth Factor I / Q000494:pharmacology*; D007335:Insulin-Like Growth Factor II / Q000494:pharmacology*; D007680:Kidney Neoplasms / Q000473:pathology*; D011994:Recombinant Proteins / Q000494:pharmacology; D014407:Tumor Cells, Cultured; D009396:Wilms Tumor / Q000473:pathology*
D011994:Recombinant Proteins; D007334:Insulin-Like Growth Factor I; D007335:Insulin-Like Growth Factor II