Insulin-like growth factor-I receptor expression and localization in benign and malignant rat mammary tumors.
The aim of this study was to investigate the expression and localization of the insulin growth factor type 1 receptor (IGF-IR) in malignant and benign mammary tumors induced in rats by N-nitroso-N-methylurea (NMU) and its correlation with histopathology and hormone dependence. Also, protein tyrosine kinase activities (PTKs) were analyzed in order to study the activation of the intracellular cascade. The results showed that IGF-IR is present in NMU tumors (analyzed by binding assay and Western blot), that a variable content is expressed in tumors that continued growing post-ovariectomy (OVX) of rats, and that it is undetectable in tumors that regressed post-OVX. IGF-IR was principally localized (by immunohistochemistry) in the epithelial cells of malignant tumors and in the fibrous cells of benign ones. Also, a significantly lower expression of both cytosolic and microsomal PTKs were found in benign tumors. Our results suggest a different expression and role of IGF-IR in benign and malignant tumors.
Cocca
Claudia
C
Radioisotopes Laboratory, School of Pharmacy and Biochemistry and, University of Buenos Aires, Argentina.
Randi
Andrea
A
Gutiérrez
Alicia
A
Núñez
Mariel
M
Croci
Máximo
M
Martín
Gabriela
G
Cricco
Graciela
G
Medina
Vanina
V
Mohamad
Nora
N
Rivera
Elena
E
Kleiman
Diana
D
Bergoc
Rosa
R
D000818:Animals; D015153:Blotting, Western; D018450:Disease Progression; D005260:Female; D007150:Immunohistochemistry; D008325:Mammary Neoplasms, Experimental / Q000201:enzymology / Q000378:metabolism* / Q000473:pathology; D009376:Neoplasms, Hormone-Dependent / Q000201:enzymology / Q000378:metabolism / Q000473:pathology; D011505:Protein-Tyrosine Kinases / Q000378:metabolism; D011869:Radioligand Assay; D051381:Rats; D017207:Rats, Sprague-Dawley; D017526:Receptor, IGF Type 1 / Q000096:biosynthesis / Q000378:metabolism*
D011505:Protein-Tyrosine Kinases; D017526:Receptor, IGF Type 1