CHARACTERIZATION OF ACYL-COA SINTHETASE 4 (ACSL4) PROMOTER IN HUMAN BREAST CANCER CELLS

DATTILO MELINA; BENZO YANINA; LOPEZ PAULA; MORDUCHOWICZ NATALIA; CASTILLO ANA FERNANADA; MALOBERTI PAULA

Mar del Plata

Congreso; LXI REUNIÓN ANUAL DE LA SOCIEDAD ARGENTINA DE INVESTIGACIÓN CLÍNICA (SAIC); 2016

ACSL4 expression in human breast cancer cells correlates withtumor aggressiveness but its regulation remains unknown. Ourobjective is to characterize the transcriptional regulation of ACSL4in breast cancer cells according to their level of aggressiveness(MDA-MB-231 and MCF-7). A 1.8 kb fragment of promoter wascloned upstream Nluc gene, a luminiscent reporter. Deletions weremade from both 5? and 3? ends. Results show there is at least o neelement in 5? region that downregulates the promoter activity inboth cell lines. Unidirectional deletion of 3? end shows a positiveregulatory 43 bp region only in MDA-MB-231 as responsible ofthe higher expression of ACSL4. Bioinformatic identification ofpossible transcription factors involved in this regulation showedconsensus sites for RORa in the 5? region and E2FF consensussites in 3? region of the promoter among others sites like CREB,SP1 and ERSS. Mutations were constructed for consensus sites potentially involved. RORa mutation increased activity in both celllines suggesting this transcription factor is involved at least inpart in the negative regulation of promoter activity in the 5? end inthese breast cancer cells. For the 3? region, E2FF mutants siteswere obtained within the region related to the differential promoteractivity. A transcriptional activity decrease was observed only inMDA-MB-231. Thus E2FF is enhancing at least in part the promoteractivity in the 3? end only in MDA-MB-231. Overexpressionof ERa in MDA-MB-231 reduced promoter activity, indicating thatERa is a negative regulator of ACSL4 expression. In regard theepigenetic mechanisms, a histone deacetylases inhibitor increasestranscription in both cell lines and a cytosine methylation inhibitorincreases transcription only in MDA-MB-231. Therefore, withthese results we could observe different transcription factors andepigenetic mechanisms that could regulate differentially ACSL4promoter in both breast cancer cell lines.