The Oncogenic Signaling Pathways in <i>BRAF</i>-Mutant Melanoma Cells Are Modulated by Naphthalene Diimide-Like G-Quadruplex Ligands

• Main Authors: Marta Recagni, Martina Tassinari, Filippo Doria, Graziella Cimino-Reale, Nadia Zaffaroni, Mauro Freccero, Marco Folini, Sara N. Richter
• Format: Article
• Language: English
• Published: MDPI AG 2019-10-01
• Series: Cells
• Subjects: <i>bcl-2</i>; g-quadruplex; <i>kit</i>; melanoma; naphthalene diimides; oncogene promoter
• Online Access: https://www.mdpi.com/2073-4409/8/10/1274

Melanoma is the most aggressive and deadly type of skin cancer. Despite the advent of targeted therapies directed against specific oncogene mutations, melanoma remains a tumor that is very difficult to treat, and ultimately remains incurable. In the past two decades, stabilization of the non-canonical nucleic acid G-quadruplex structures within oncogene promoters has stood out as a promising approach to interfere with oncogenic signaling pathways in cancer cells, paving the way toward the development of G-quadruplex ligands as antitumor drugs. Here, we present the synthesis and screening of a library of differently functionalized core-extended naphthalene diimides for their activity against the <i>BRAFV600E</i>-mutant melanoma cell line. The most promising compound was able to stabilize G-quadruplexes that formed in the promoter regions of two target genes relevant to melanoma, <i>KIT</i> and <i>BCL-2</i>. This activity led to the suppression of protein expression and thus to interference with oncogenic signaling pathways involved in <i>BRAF</i>-mutant melanoma cell survival, apoptosis, and resistance to drugs. This G-quadruplex ligand thus represents a suitable candidate for the development of melanoma treatment options based on a new mechanism of action and could reveal particular significance in the context of resistance to targeted therapies of <i>BRAF</i>-mutant melanoma cells.