Reduced mammary tumor progression in a transgenic mouse model fed an isoflavone-poor soy protein concentrate.
Dietary exposure to soy has been associated with reduced breast cancer incidence. Soy isoflavones and protein components, such as protease inhibitors and the lunasin peptide, have been indicated as potential agents reducing carcinogenesis. In this study, the effect of soy-based diets was evaluated in a transgenic mouse model of breast carcinoma, overexpressing the neu oncogene. Neu female mice were fed for 20 wk a soy- and isoflavone-free diet (IFD), 4RF21 laboratory mouse diet, soy-based, thus isoflavone-rich (STD), or AIN-76-based semisynthetic diets with a soy protein isolate (SPI) or an isoflavone-poor soy protein concentrate (IPSP) as protein source. Mice were then sacrificed and tumors removed. Mammary tumor weights were not different in SPI versus IFD and STD fed mice. In contrast, mice fed IPSP showed reduced tumor progression versus IFD and STD groups (p < 0.05). Moreover, IPSP fed mice showed lower bromo-2'-deoxyuridine (BrdU) incorporation into breast tumor cells compared to STD and SPI fed animals (p < 0.02). Lung metastases were detected in 80% of IFD fed mice, in 70% of mice fed STD and SPI, and only in 50% of the IPSP fed animals. These results indicate that a diet containing an isoflavone-poor soy protein concentrate may inhibit breast tumor progression and metastasis development.
Chiesa
Giulia
G
Department of Pharmacological Sciences, University of Milano, Milan, Italy. giulia.chiesa@unimi.it
Rigamonti
Elena
E
Lovati
Maria R
MR
Disconzi
Emanuela
E
Soldati
Sabina
S
Sacco
Maria G
MG
Catò
Enrica Mira
EM
Patton
Veronica
V
Scanziani
Eugenio
E
Vezzoni
Paolo
P
Arnoldi
Anna
A
Locati
Daniela
D
Sirtori
Cesare R
CR
D000818:Animals; D000972:Antineoplastic Agents, Phytogenic / Q000494:pharmacology*; D049109:Cell Proliferation; D004032:Diet; D018450:Disease Progression; D005260:Female; D007529:Isoflavones / Q000494:pharmacology*; D008325:Mammary Neoplasms, Experimental / Q000178:diet therapy* / Q000517:prevention & control; D051379:Mice; D008822:Mice, Transgenic; D030262:Soybean Proteins / Q000494:pharmacology*
D000972:Antineoplastic Agents, Phytogenic; D007529:Isoflavones; D030262:Soybean Proteins