| First Author | Elizalde PV | Year | 1997 |
| Journal | Medicina (B Aires) | Volume | 57 Suppl 2 |
| Pages | 70-4 | PubMed ID | 9580484 |
| Mgi Jnum | J:43369 | Mgi Id | MGI:1097549 |
| Citation | Elizalde PV, et al. (1997) [Growth hormones and oncogenes in mammary adenocarcinomas induced by medroxy- progesterone acetate in BALB/c mice]. Medicina (B Aires) 57 Suppl 2:70-4 |
| abstractText | We have studied the involvement of growth factors (GF), their receptors (GF-R) and oncogenes in modulating tumor growth in the medroxyprogesterone acetate (MPA)-induced mammary tumor model in BALB/c mice. We demonstrated the presence of both ligands of the insulin-like growth factor family (IGF-I, IGF-II) and the two types of receptors (IGF-RI, IGF-RII). MPA upregulated IGF-II mRNA and protein levels in hormone-dependent lines (MPA-D). The progression to a hormone-independent phenotype was accompanied by a high constitutive expression of IGF-II and by a significant decrease in IGF-IIR number. An antisense strategy used to evaluate the role of IGF in the MPA-induced growth of epithelial MPA-D cells showed that IGF mediate progestin-induced mammary tumor growth by autocrine/intracrine pathways. We also studied the role of heregulins (HRG), the recently identified ligands for the c-erbB3 and c-erbB4 oncogenes. HRG mRNA expression was restricted to tumors of ductal origin. MPA induced an in vivo up-regulation of HRG expression. Finally, we also found that MPA may be exerting its proliferative effect on MPA-D lines by inhibiting the expression of transforming growth factor beta 1, (TGF-beta 1) and the lack of expression of TGF-beta 1 in hormone-independent tumors may be related to the acquisition of autonomous growth. |
