The Insulin receptor, c-fos and PCNA expression in rat mammary carcinogenesis.

GUTIÉRREZ, A; MARTÍN G; SAMBUCO, L; NÚÑEZ, M; CRICCO, G; RIVERA, E; ALVAREZ, L; BERGOC, R

Rosario, Argentina

Congreso; XLII Reunión Anual de la Sociedad Argentina de Investigación en Bioquímica y Biología Molecular; 2006

Sociedad Argentina de Investigación en Bioquímica y Biología Molecular

We have developed experimental malignant mammary tumors in normal rats and benign lesions in diabetic ones by three ip injections of N-Nitroso-N-Methylurea (NMU) at 50, 80 and 110 days of animals life. The aim of this work was to study expression of insulin receptor (IR), PCNA and FOS protein in the mammary gland during the carcinogenic process in these animals. Eight groups of rats were used: 1) control; 2) tamoxifen (Tam) treated; 3) NMU injected; 4) NMU injected and Tam treated; 5) diabetic; 6) diabetic and Tam treated; 7) diabetic and NMU injected; 8) diabetic, NMU injected and Tam treated. All gland mammary tissues were processed at 60, 90 and 120 days. Western blot and immunohistochemical methods were employed. The results indicate: A) IR expression is increased in group 3 vs 1 during all the observation period. Group 4 discloses IR expression similar to 3, while group 2 is positively stained only at 120 days. IR is lower in all groups of diabetic rats compared to non diabetic-ones. B) PCNA expression in diabetic rats is lesser than in non diabetic ones. NMU injected groups shows higher PCNA staining than non injected ones. C) FOS expression is slighter in diabetic groups. In summary, the differences observed in proteins expression can be correlated to the more benign histological pattern found in tumors of diabetic vs non diabetic rats. POSTER