URTREGER Alejandro Jorge
congresos y reuniones científicas
All-Trans Retinoic Acid and Pharmacological Inhibition of PKCa Synergize to Inhibit Tumour Progression and Impairs Self-renewal of Cancer Stem Cells in a Triple Negative Mammary Cancer Model
DAMIAN E. BERARDI; MARIA I. DIAZ BESSONE; STÉFANO M. CIRIGLIANO; AGUSTINA TARUSELLI; ELISA D. BAL DE KIER JOFFE; ALEJANDRO J. URTREGER; LAURA B. TODARO
Ciudad Autónoma de Buenos Aires
Simposio; Simposio Internacional: Ganando la Guerra Contra el Cáncer; 2016
Ministerio de Ciencia y Técnica
Introduction: Retinoids exert different effects on malignant phenotype reversion through the crosstalk with PKC pathway. We proposed to: A) Evaluate the combined effect of All-Trans Retinoic Acid (ATRA) and PKCa inhibitor (Go6976) on: 1) cell proliferation, migration and cancer stem cells (CSC) self-renewal and differentiation 2) Retinoic Acid Receptors (RARs) levels B) Study the effect of ATRA/PKCa inhibitor treatment on tumor progression in vivo.Methods: We employed a murine mammary triple negative cell model (LM38-LP), composed by luminal (LEP), myoepithelial (MEP) and CSC. We perform RT-PCR to measure RARs. Drug interaction was analyzed by Chou-Talalay?s method. Migration potential was studied by wound-healing assay. We employed mammoesphere assays to evaluated CSC. 3D culture in Matrigel to evaluate differentiation. LM38-LP cells were inoculated orthotopically to get tumors in BALB/c mice?s, for in vivo studies.Results: We found an inhibitory effect on cell proliferation exerted by ATRA/PKCa inhibitor that was synergistic by Chou-Talalay?s method. Furthermore, ATRA/PKCa inhibitor treatment reduced LM38-LP migration more efficiently than each treatment alone, showing a synergic effect. In a 3D matrigel culture assay, ATRA pre-treated CSC formed polarized colonies with presence of lumen. PKCa inhibition impairs lumen formation induced by ATRA but led to smaller colonies. ATRA/PKCa inhibitor treatment synergized to reduce mammospheres growth. Surprisingly, ATRA treatment induced CSC self-renewal but the blockage of PKCa activity impairs this effect. Interestingly, we found that ATRA treatment increased RARb2 and RARg2 in CSC. In addition, we observed that only the combined treatment induced a decrease of RARg2 in the migratory MEP cells and impairs RARg2 induction by ATRA in CSC. Finally, we observed that the combined treatment reduced LM38-LP tumor growth and metastatic spread in a synergic manner.Conclusions: Our findings suggest that ATRA and PKCa inhibition synergize to inhibit tumor progression in vitro and in vivo possibly through the decrease of RARg2.