The microphthalmia-associated transcription factor is involved in gastrointestinal stromal tumor growth

• Published in: Cancer gene therapy Vol. 30; no. 2; pp. 245 - 255
• Main Authors: Proaño-Pérez, Elizabeth, Serrano-Candelas, Eva, García-Valverde, Alfonso, Rosell, Jordi, Gómez-Peregrina, David, Navinés-Ferrer, Arnau, Guerrero, Mario, Serrano, César, Martín, Margarita
• Format: Journal Article
• Language: English
• Published: New York Nature Publishing Group US 01.02.2023; Nature Publishing Group
• Subjects: 13; 13/2; 42/89; 631/67/1504/1829; 692/699/67/1504; Adaptor proteins; Apoptosis; Biomedical and Life Sciences; Biomedicine; Cell cycle; Cell survival; Cell Transformation, Neoplastic; Cell viability; Gastrointestinal cancer; Gastrointestinal Stromal Tumors - pathology; Gene Expression; Gene Therapy; Humans; Intermediates; Isoforms; Mesenchyme; Microphthalmia-associated transcription factor; Microphthalmia-Associated Transcription Factor - genetics; Microphthalmia-Associated Transcription Factor - metabolism; Mutation; Proto-Oncogene Proteins c-kit - genetics; Proto-Oncogene Proteins c-kit - metabolism; Signal Transduction; Survival factor; Transcription factors; Tumorigenesis
• ISSN: 0929-1903; 1476-5500
• DOI: 10.1038/s41417-022-00539-1

Gastrointestinal stromal tumors (GISTs) are the most common neoplasms of mesenchymal origin, and most of them emerge due to the oncogenic activation of KIT or PDGFRA receptors. Despite their relevance in GIST oncogenesis, critical intermediates mediating the KIT/PDGFRA transforming program remain mostly unknown. Previously, we found that the adaptor molecule SH3BP2 was involved in GIST cell survival, likely due to the co-regulation of the expression of KIT and Microphthalmia-associated transcription factor (MITF). Remarkably, MITF reconstitution restored KIT expression levels in SH3BP2 silenced cells and restored cell viability. This study aimed to analyze MITF as a novel driver of KIT transforming program in GIST. Firstly, MITF isoforms were characterized in GIST cell lines and GIST patients’ samples. MITF silencing decreases cell viability and increases apoptosis in GIST cell lines irrespective of the type of KIT primary or secondary mutation. Additionally, MITF silencing leads to cell cycle arrest and impaired tumor growth in vivo. Interestingly, MITF silencing also affects ETV1 expression, a linage survival factor in GIST that promotes tumorigenesis and is directly regulated by KIT signaling. Altogether, these results point to MITF as a key target of KIT/PDGFRA oncogenic signaling for GIST survival and tumor growth.