Effects of high and low dietary fat and indomethacin on tumour growth, hormone receptor status and growth factor expression in DMBA-induced rat breast cancer.
The effects of high and low dietary fat (20% vs. 0.5% corn oil), and of the prostaglandin synthetase inhibitor indomethacin (0.005% w/w), on tumour incidence, tumour growth, hormone-receptor status and growth-factor expression were examined in dimethylbenzanthracene (DMBA)-induced rat breast cancer. The high dietary-fat group showed a significantly higher tumour incidence, larger tumour size and larger number of bromodeoxyuridine(BrdU)-positive cells of tumours as compared with those in the low dietary-fat group. Indomethacin reduced tumour incidence significantly, but conversely increased the tumour size and the number of BrdU-positive cells in both the high and the low dietary-fat groups. No significant difference was noted in the hormone-receptor status of the tumours. Growth factors (TGF-alpha and IGF-II) were somewhat highly expressed in the high dietary-fat group as compared with the low dietary-fat group, but indomethacin rather reduced the growth-factor expression. It is concluded that high dietary fat stimulates tumour incidence and tumour proliferation, while indomethacin has dual effects: a stimulating effect on tumour proliferation, but an inhibiting effect on tumour incidence. It is also suggested that hormone-receptor status and growth-factor expression do not play an important role in their stimulating effects on tumour proliferation.
Mizukami
Y
Y
Pathology Section, Kanazawa University Hospital, Japan.
Nonomura
A
A
Noguchi
M
M
Taniya
T
T
Thomas
M
M
Nakamura
S
S
Miyazaki
I
I
D015127:9,10-Dimethyl-1,2-benzanthracene; D000818:Animals; D001835:Body Weight / Q000187:drug effects; D001973:Bromodeoxyuridine; D002455:Cell Division / Q000187:drug effects; D004042:Dietary Fats, Unsaturated / Q000008:administration & dosage*; D005260:Female; D006133:Growth Substances / Q000032:analysis*; D007150:Immunohistochemistry; D015994:Incidence; D007213:Indomethacin / Q000494:pharmacology*; D008325:Mammary Neoplasms, Experimental / Q000139:chemically induced* / Q000378:metabolism / Q000473:pathology / Q000517:prevention & control; D051381:Rats; D017207:Rats, Sprague-Dawley; D011960:Receptors, Estrogen / Q000187:drug effects*; D011980:Receptors, Progesterone / Q000187:drug effects*
D004042:Dietary Fats, Unsaturated; D006133:Growth Substances; D011960:Receptors, Estrogen; D011980:Receptors, Progesterone; D015127:9,10-Dimethyl-1,2-benzanthracene; D001973:Bromodeoxyuridine; D007213:Indomethacin