Mechanism of growth inhibition by calpain inhibitor in MCF-7 cells.
BACKGROUND
A calpain inhibitor, calpeptin, inhibited the cell growth of ER (estrogen receptor) positive breast cancer cells, such as MCF-7, T-47D, and ZR-75-1 in the presence of E2. The mechanism of this inhibition has not been clarified yet.


METHODS
MCF-7 cells were employed to investigate the mechanism of the inhibition. We studied the effect of calpeptin on the secretion of insulin-like growth factor-I (IGF-I) and transforming growth factor (TGF-alpha).


RESULTS
The secretion of IGF-I or TGF-alpha was not changed by calpeptin either in the presence or absence of E2. Moreover, the binding of IGF-I or TGF-alpha to MCF-7 cells augmented by the addition of E2 was not affected by calpeptin.


CONCLUSIONS
These results indicated that the inhibition of cell growth in MCF-7 by calpeptin was not due to the modulation of autocrine growth factors and their receptors.
Shiba
E
E
Department of Surgical Oncology, Osaka University Medical School, Suita, Japan.
Kim
S J
SJ
Kambayashi
J
J
Kawamura
I
I
Lacey
E
E
Manda
T
T
Shimomura
K
K
Taguchi
T
T
Takai
S
S
D001943:Breast Neoplasms; D002154:Calpain / Q000037:antagonists & inhibitors*; D002455:Cell Division / Q000187:drug effects; D015853:Cysteine Proteinase Inhibitors / Q000494:pharmacology; D004151:Dipeptides / Q000494:pharmacology*; D066246:ErbB Receptors / Q000187:drug effects / Q000378:metabolism; D004958:Estradiol / Q000494:pharmacology*; D005260:Female; D006801:Humans; D007334:Insulin-Like Growth Factor I / Q000096:biosynthesis / Q000378:metabolism*; D007700:Kinetics; D017526:Receptor, IGF Type 1 / Q000187:drug effects / Q000378:metabolism; D011960:Receptors, Estrogen / Q000187:drug effects / Q000378:metabolism; D011980:Receptors, Progesterone / Q000187:drug effects / Q000378:metabolism; D016211:Transforming Growth Factor alpha / Q000096:biosynthesis / Q000378:metabolism*; D014407:Tumor Cells, Cultured
D015853:Cysteine Proteinase Inhibitors; D004151:Dipeptides; D011960:Receptors, Estrogen; D011980:Receptors, Progesterone; D016211:Transforming Growth Factor alpha; C071482:calpeptin; D004958:Estradiol; D007334:Insulin-Like Growth Factor I; D066246:ErbB Receptors; D017526:Receptor, IGF Type 1; D002154:Calpain