CDC42 REVERTS AGGRESSIVENESS OF A TRIPLE NEGATIVE BREAST CANCER CELL LINE TROUGH METHYLATION OF ID4 PROMOTER

NASIF DANIELA; LAURITO SERGIO; CAMPOY, EMANUEL; ROQUÉ MARIA; BRANHAM MARIA T

Congreso; REUNIÓN CONJUNTA DE SOCIEDADES DE BIOCIENCIAS; 2017

Breast cancer constitutes a group of diseases characterized by different morphologies and biological behaviors. Molecularly they can be classified as luminal A, luminal B, human epidermal growth factor receptor 2, and triple-negative breast cancers (TN); lacking ER/PR/HER2. Clinically, the TN subtype has an aggressive nature, higher rates of relapse and shorter overall survival. TN tumors affect younger patients and are more prevalent in African-American and Latin women. Cdc42 is a plasma membrane-associated small GTPase which is involved in the regulation of several cellular functions and its expression is dysregulated in several tumor types. Here we show that Cdc42 overexpression reduced TN aggressive phenotype through the methylation of ID4 (inhibitor of Differentiation) promoter. Briefly, MDA-MB321 cell lines were transfected with a Cdc42GFP vector and afterwards ID4 methylation status was measured by droplet digital and conventional Methyl Specific PCR. MS-MLPA assay revealed that ID4 methylation increased significantly in the Cdc42 transfected cells and interestingly, the methylation values of other genes remained unchanged. WB assay revealed that ID4 protein expression decreased after cdc42 transfection. Since ID4 inversely regulates BRCA1 expression in breast tumors, we evaluated BRCA1 status after transfection. Our results show that BRCA1 protein expression increased in the Cdc42 transfected cells. Migration and Apoptosis assays by wound healing and flow cytometry determined that the transfected cells migrated less (p