EXPRESSION OF EPITHELIAL CADHERIN (Ecad) IN HUMAN BREAST CANCER CELL LINES IBH-4 AND IBH-6

LAPYCKYJ, LARA; MATOS, MARÍA LAURA; CASTILLO, LILIAN; LENTZ, EZEQUIEL; GABRIELLI, NIEVES; LUTHY, ISABEL; VAZQUEZ-LEVIN, MÓNICA HEBE

Huerta Grande, Córdoba, Argentina.

Congreso; I Reunión Conjunta de Sociedades de Biología de la República Argentina”.; 2007

Introduction: Ecad is a 120 kDa transmembrane protein involved in cell-cell adhesion. Human breast cancer cell lines IBH-4 and IBH-6 are highly invasive and have a distinct C-term truncated 89 KDa Ecad form (Ecad89). Objective: To further characterize Ecad expression in IBH-4/IBH-6 cell lines. Methods: Protein analysis involved immunocytochemistry and Western immunoblotting with antibodies to different Ecad domains. Protein levels were estimated by densitometry using rec-Ecad as mass standard. mRNA analysis was done by RT-PCR. MCF-7 cells served as control. Results: In IBH-6 and IBH-4 cells: 1) Ecad protein levels decreased to 30% and 10% compared to MCF-7 (0.6 ng/mg cell protein) and 2) Ecad localization was weak and patchy along the cell. Ecad protein changes did not result from culture stress (similar results in cultures with 10/2/0% FCS). No accumulation of 35KDa Ecad was detected, and Ecad89 did not co-migrate with the Ecad ectodomain. Ecad mRNA levels were low in IBH-4 and IBH-6, and mapping studies revealed major changes in its 3’end. Conclusion: significant changes in Ecad expression (mRNA and protein) were found in IBH-4 and IBH-6 cells.