Insulin-like growth factor II mRNA expression in human breast cancer.
Insulin-like growth factor II is a growth factor important in fetal development. Several cancer tissues and cell lines have been reported to express IGF-II and rat IGF-II is mitogenic for breast cancer cell lines. Using Northern analysis and ribonuclease protection assays, IGF-II mRNA was detected in normal fibroblasts and in the established breast cancer cell line, T47D. In this cell line, steady state levels of IGF-II message were increased by treatment with estradiol. 10 nM IGF-II, purified from human serum, was mitogenic for breast cancer cell lines. In vitro, IGF-II may act as an autocrine growth factor for some cell lines. RNA derived from breast cancer, pathologically normal breast tissue, and benign breast disease also contained IGF-II mRNA. When paired samples of normal and cancer tissue were obtained from the breast of the same patient, the level of IGF-II mRNA expression in the normal tissue was at least that found in the cancer. This is consistent with previous observations that show IGF-II is expressed in mesenchyme. These findings suggest that in breast cancer IGF-II is produced by stromal tissue elements and potentially by the malignant epithelial cells. Therefore, IGF-II may function as an autocrine or a paracrine growth factor in different breast tumors.
Yee
D
D
Medical Breast Cancer Section National Cancer Institute, Bethesda, Maryland.
Cullen
K J
KJ
Paik
S
S
Perdue
J F
JF
Hampton
B
B
Schwartz
A
A
Lippman
M E
ME
Rosen
N
N
D015152:Blotting, Northern; D001943:Breast Neoplasms / Q000378:metabolism* / Q000473:pathology; D004967:Estrogens / Q000494:pharmacology; D005260:Female; D005786:Gene Expression Regulation / Q000187:drug effects; D006801:Humans; D007335:Insulin-Like Growth Factor II / Q000235:genetics* / Q000494:pharmacology; D012333:RNA, Messenger / Q000032:analysis*; D013002:Somatomedins / Q000235:genetics*; D014407:Tumor Cells, Cultured
D004967:Estrogens; D012333:RNA, Messenger; D013002:Somatomedins; D007335:Insulin-Like Growth Factor II