Cyclin A expression in experimental models of breast cancer with different levels of progesterone receptor isoforms

MELINA E. BILINSKI; VICTORIA T. FABRIS; MARINA AYRE; CLAUDIA LANARI; BRITTA M. JACOBSEN

Mar del Plata

Congreso; Reunión Anual de la Sociedad Argentina de Investigación Clínica; 2016

SAIC

Deregulation of cyclins expression is frequently found in breast cancer and has been associated with aneuploidy. We have previously reported an overexpression of cyclin A in two aneuploid antiprogestin resistant tumors derived from C4-HD, a mammary carcinoma induced by medroxyprogesterone acetate (MPA) that shows a progestin dependent pattern of tumor growth and high levels of progesterone receptors (PR). Taking into account that antiprogestin sensitive tumors show higher levels of isoform A of progesterone receptor (PRA) than isoform B (PRB) and that antiprogestin resistant variants show the opposite ratio, we decided to study the expression of cyclin A in other experimental models of breast cancer bearing different ploidy levels and different PRA/PRB ratios. An increase in cyclin A expression was observed by Western blots in the acquired resistant variant C7-2-HIR and in the constitutive resistant C7-HI tumor (1.7 fold and 1.5 fold, respectively) compared to the responsive tumor C7-2-HI (p