THE EFFECT OF NEW ANTI-ERBB2 THERAPIES AND RETINOIC ACID IN HUMAN BREAST CANCER CELL PROLIFERATION

REDONDO ANALIA; VANDERHOEVEN FIORELLA; FLAMINI MARINA INÉS; VARGAS ROIG LAURA; MARTÍNEZ ANA LAURA; SANCHEZ MATÍAS

Congreso; XXXIV Reunión Científica Anual de la Sociedad de Biología de Cuyo; 2016

Sociedad de Biología de Cuyo

Breast cancer is classified in molecular subtypes according to the presence/absence of estrogen receptor, progesterone receptor and ErbB-2. Tumors overexpressing ErbB-2 are more aggressive and metastatic; hence patients have a poor prognosis. Therefore, anti-ErbB2 strategies have been developed, for instance the monoclonal antibody Trastuzumab. Currently they are being used in clinic treatments. Despite this progress, not all patients respond to the treatment. Thus, it is necessary to develop new therapeutic approaches based on the combination of different existing drugs. Retinoids have been proposed in the adjuvant treatment of breast carcinoma because of their ability to inhibit cell growth. Objectives: 1) To evaluate the effect of different concentrations of trastuzumab and retinoic acid (RA) on cell proliferation. 2) To determine whether the combination of both drugs exerts a synergistic effect on the reduction of cell proliferation. Methodology: SKBR-3 and BT-474 breast cancer cell lines were used. The MTT assay and immunofluorescence were performed. Results: Seventy two hours treatments of SKBR-3 and BT-474 cells with different doses of Trastuzumab (0.1-1-10-100 μg/ml) and retinoic acid (10-8- 10-7-10-6- 10-5 M) are effective decreasing cell proliferation in a dose-dependent manner. Additionally, combination of both drugs (Trastuzumab 1-10-100 μg/ml and retinoic acid 10-6 M) yields a potentiating effect on cell proliferation reduction which was observed in SKBR-3 cells but not in BT-474 cells. Conclusion: the sensibility to anti-Erb2 therapies could be even greater with RA coadministration in ER-/ErbB-2+ tumors.