The insulin receptor content is increased in breast cancers initiated by three different oncogenes in transgenic mice.
The Insulin Receptor (IR) is a potential oncogene for mammary epithelial cells since its content is increased in most human breast cancer specimens, and both ligand-dependent malignant transformation and ligand-dependent enhanced growth occurs in cultured breast cells overexpressing the IR. To better understand whether the IR plays a role in mammary carcinogenesis which is independent of other initiation factors, we measured IR content in transgenic mouse models of breast cancer induced by 3 known oncogenes (Wnt-1, Neu, and Ret). Insulin receptor content was measured by a specific radioimmunoassay. In normal mammary gland tissues IR content was 14.6 +/- 1.4 ng/mg of protein (mean +/- SEM, n = 6). In the 3 cancers IR content was elevated (Neu = 36.1 +/- 4.6, n = 8, p < 0.002; Wnt-1 = 38.3 +/- 2.6, n = 13, p < 0.001; and Ret = 53.6 +/- 7.1, n = 7, p < 0.001). These data indicate that IR overexpression, in addition to being a potential oncogene, is increased in mouse tumors initiated by other oncogenes, and therefore may also play a supportive role in the growth of breast cancers.
Frittitta
L
L
Istituto di Medicina Interna, Endocrinologia e Malattie del Metabolismo, Università di Catania, Ospedale Garibaldi, Italy.
Cerrato
A
A
Sacco
M G
MG
Weidner
N
N
Goldfine
I D
ID
Vigneri
R
R
D000818:Animals; D005260:Female; D008297:Male; D008321:Mammary Glands, Animal / Q000737:chemistry; D015674:Mammary Neoplasms, Animal / Q000737:chemistry* / Q000235:genetics / Q000473:pathology; D051379:Mice; D008822:Mice, Transgenic; D009857:Oncogenes / Q000235:genetics*; D011863:Radioimmunoassay; D011972:Receptor, Insulin / Q000032:analysis*
D011972:Receptor, Insulin