MODULATION OF GENES AND PROTEINS RELATED TO METASTATIC PROCESSES IN RETINOIC ACID-SENSITIVE AND RESISTANT BREAST CANCER CELLS

VANDERHOEVEN, FIORELLA; CASTRO-GUIJARRO, ANA CARLA; MONDACA, JOSELINA MAGALÍ; REDONDO, ANALÍA; SANCHEZ, ANGEL MATIAS; FLAMINI, MARINA INÉS

Congreso; XLI Reunión Científica Anual de la Sociedad de Biología de Cuyo; 2023

Breast cancer (BC) is women's most frequent malignant neoplasia and has a high mortality rate. All-trans retinoic acid (RA) is a vitamin Aderived pleiotropic signaling molecule that regulates critical genetic programs. Although RA has demonstrated a potent anticarcinogenicactivity, its use in solid tumors is limited. Previous studies showed that MDA-MB-231, MDA-MB-468, T-47D and SK-BR3, BC cell lines,have different RA sensitivity and RA-growth inhibitory effects. We have previously demonstrated that RA decreases cell migration in RAsensitive BC cells by reducing the expression of movement-fundamental proteins. Furthermore, we determined how RA-pathwayphosphorylates/activates and redistributes these proteins, ultimately inhibiting BC cell migration. Metalloproteases (MMPs) are proteinsinvolved in the degradation of the extracellular matrix, promoting invasion and metastasis. MMPs are closely related to E-Cadherin andVimentin, protein markers of Epithelial/Mesenchymal Transition (EMT), and their levels affect cell adhesion and migration. We propose tocharacterize target gene expression profiles in RA-treated BC cell lines using the Gene Expression Omnibus (GEO) public repository andto determine the effect of RA in RA-sensitive or resistant BC cells on cell viability and proliferation. We also propose to determine the rolein the EMT process. We performed bioinformatics analysis using GEO (GSE103426) to determine differential gene expression in RAresistant cell lines by volcano plots and in-vitro experiments to assess the effect of RA on cell viability by MTT assay and protein expressionby Western Blot in RA-sensitive and RA-resistant cell lines. Differential gene expression analysis of controls vs. treated with RA (100 nM,18 h) MDA-MB-231 and MDA-MB-468 cells showed that RA modulates migration-related gene expression similarly in both lines.Interestingly, genes related to proliferation were not affected. The viability of MDA-MB-231 cells was not reduced after different doses ofRA, demonstrating their resistance to RA. In contrast, RA decreased the viability of T-47D cells, confirming their sensitivity to RA. Wealso observed that retinoic acid receptors (RARα, RARβ and RARγ) were expressed at different levels within BC cells. This fact coincideswith RA-sensitivity reported for BC cells, where T-47D and SK-BR3 are considered RA-sensitive and MDA-MB-231 RA-resistant basedon their high and low expression of RARs, respectively. Finally, RA treatment modulated EMT- related proteins, E-Cadherin, Vimentin,and metalloproteases MMP2 and MMP9 in both cell lines. In conclusion, despite the absence of RAR receptors, RA affects and modulatesmRNA and protein levels in RA-resistant cells and affects the expression of proteins involved in the migratory process in sensitive andresistant cells. These results could be significant as a potential therapy for metastatic breast cancers without specific treatment.