Abstract 202: Spry1 targeting enhances E-cadherin expression in cutaneous melanoma
Authors: Montico Barbara , Giurato Giorgio , Guerrieri Roberto , Salvati Annamaria , Colizzi Francesca , Baboci Lorena , Sigalotti Luca , Covre Alessia , Maio Michele , Steffan Agostino , Nyman Tuula Anneli , Weisz Alessandro , Mongiat Maurizio , Andreuzzi Eva , Fratta Elisabetta 
Published: March 2024

Abstract
Background: Cutaneous melanoma (CM) is a very aggressive malignancy that still represents the deadliest form of skin cancer. About 50% of CM harbors the activating BRAFV600 mutation which exerts most of the oncogenic effects through the MAPK signaling pathway. In the last years, a number of MAPK modulators have been identified, including Spry1. In this context, we have recently reported that Spry1 knockdown (Spry1KO) reduced the expression of several markers of epithelial-mesenchymal transition (EMT) both in vitro and in vivo. Loss of E-cadherin is a hallmark of EMT in CM, and the presence of aberrant E-cadherin expression in CM is usually associated with a significantly worse overall survival. Based on these premises, in this study we wondered to explore whether Spry1 influences EMT through the modulation of E-cadherin expression.
Material and Methods: SPRY1 gene was knocked-out using the CRISPR strategy in BRAF wild-type (wt) and in BRAF-mutant CM cell lines. By using in vitro and in vivo models, the effects of Spry1KO on E-cadherin expression and localization was investigated through RNA-sequencing (RNA-seq), quantitative real-time PCR, western blot, and immunofluorescence analyses. To gain insight into Spry1 interactome, immunoprecipitation coupled to mass spectrometry (IP-MS) was performed.
Results and Discussion: E-cadherin mRNA and protein levels were significantly increased both in vitro and in vivo in Spry1KO clones. In addition, immunofluorescence analysis revealed a sustained redistribution of E-cadherin to the plasma membrane following Spry1 loss, thus confirming that Spry1 plays a role in EMT in CM. E-cadherin requires p120-catenin (p120) to maintain cell adhesion and functional adherens junctions. Indeed, p120 dysregulation results in the rapid turnover of E-cadherin complexes. Intriguingly, IP-MS analyses identified several Spry1 protein partners, including p120. Although a number of functional studies are still ongoing, preliminary western blot analysis of cytosolic and mitochondrial proteins indicated that Spry1 and p120 were mostly located in mitochondria.
Conclusion: Spry1 reduced E-cadherin expression in vitro and in vivo. Starting from preliminary data, we hypothesized that Spry1-p120 interaction might influence E-cadherin distribution over the plasma membrane.
Citation Format: Barbara Montico, Giorgio Giurato, Roberto Guerrieri, Annamaria Salvati, Francesca Colizzi, Lorena Baboci, Luca Sigalotti, Alessia Covre, Michele Maio, Agostino Steffan, Tuula Anneli Nyman, Alessandro Weisz, Maurizio Mongiat, Eva Andreuzzi, Elisabetta Fratta. Spry1 targeting enhances E-cadherin expression in cutaneous melanoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 202.