Context-dependent miR-204 and miR-211 affect the biological properties of amelanotic and melanotic melanoma cells

Abstract

// Marianna Vitiello 1, 2 , Andrea Tuccoli 1 , Romina D’Aurizio 3 , Samanta Sarti 1, 4 , Laura Giannecchini 1 , Simone Lubrano 1, 4 , Andrea Marranci 1, 4 , Monica Evangelista 2 , Silvia Peppicelli 5 , Chiara Ippolito 6 , Ivana Barravecchia 7 , Elena Guzzolino 7 , Valentina Montagnani 8 , Michael Gowen 9 , Elisa Mercoledi 1 , Alberto Mercatanti 2 , Laura Comelli 2 , Salvatore Gurrieri 1 , Lawrence W. Wu 10 , Omotayo Ope 10 , Keith Flaherty 11 , Genevieve M. Boland 11 , Marc R. Hammond 11 , Lawrence Kwong 12 , Mario Chiariello 2, 13 , Barbara Stecca 8 , Gao Zhang 10 , Alessandra Salvetti 14 , Debora Angeloni 7 , Letizia Pitto 2 , Lido Calorini 5 , Giovanna Chiorino 15 , Marco Pellegrini 3 , Meenhard Herlyn 10 , Iman Osman 9 , Laura Poliseno 1, 2 1 Oncogenomics Unit, Core Research Laboratory, Istituto Toscano Tumori (ITT), AOUP, Pisa, Italy 2 Institute of Clinical Physiology (IFC), CNR, Pisa, Italy 3 Laboratory of Integrative Systems Medicine (LISM), Institute of Informatics and Telematics (IIT), CNR, Pisa, Italy 4 University of Siena, Italy 5 Section of Experimental Pathology and Oncology, Department of Experimental and Clinical Biomedical Sciences, University of Firenze, Italy 6 Unit of Histology, Department of Clinical and Experimental Medicine, University of Pisa, Italy 7 Scuola Superiore Sant’Anna, Pisa, Italy 8 Tumor Cell Biology Unit, Core Research Laboratory, Istituto Toscano Tumori (ITT), AOUC, Firenze, Italy 9 New York University, New York, NY, USA 10 The Wistar Institute, Philadelphia, PA, USA 11 Massachusetts General Hospital, Boston, MA, USA 12 MD Anderson Cancer Center, Houston, TX, USA 13 Signal Transduction Unit, Core Research Laboratory, Istituto Toscano Tumori (ITT), AOUS, Siena, Italy 14 Unit of Experimental Biology and Genetics, Department of Clinical and Experimental Medicine, University of Pisa, Italy 15 Fondazione Edo and Elvo Tempia, Biella, Italy Correspondence to: Laura Poliseno, email: laura.poliseno@gmail.com Keywords: melanoma, BRAFV600E, ERK pathway, miR-204 family, context-dependency Received: March 11, 2016      Accepted: February 06, 2017      Published: March 06, 2017 ABSTRACT Despite increasing amounts of experimental evidence depicting the involvement of non-coding RNAs in cancer, the study of BRAFV600E-regulated genes has thus far focused mainly on protein-coding ones. Here, we identify and study the microRNAs that BRAFV600E regulates through the ERK pathway. By performing small RNA sequencing on A375 melanoma cells and a vemurafenib-resistant clone that was taken as negative control, we discover miR-204 and miR-211 as the miRNAs most induced by vemurafenib. We also demonstrate that, although belonging to the same family, these two miRNAs have distinctive features. miR-204 is under the control of STAT3 and its expression is induced in amelanotic melanoma cells, where it acts as an effector of vemurafenib’s anti-motility activity by targeting AP1S2. Conversely, miR-211, a known transcriptional target of MITF, is induced in melanotic melanoma cells, where it targets EDEM1 and consequently impairs the degradation of TYROSINASE (TYR) through the ER-associated degradation (ERAD) pathway. In doing so, miR-211 serves as an effector of vemurafenib’s pro-pigmentation activity. We also show that such an increase in pigmentation in turn represents an adaptive response that needs to be overcome using appropriate inhibitors in order to increase the efficacy of vemurafenib. In summary, we unveil the distinct and context-dependent activities exerted by miR-204 family members in melanoma cells. Our work challenges the widely accepted “same miRNA family = same function” rule and provides a rationale for a novel treatment strategy for melanotic melanomas that is based on the combination of ERK pathway inhibitors with pigmentation inhibitors.