Synthetic MIR143-3p Suppresses Cell Growth in Rhabdomyosarcoma Cells by Interrupting RAS Pathways Including PAX3–FOXO1

• Main Authors: Nobuhiko Sugito, Kazuki Heishima, Yuko Ito, Yukihiro Akao
• Format: Article
• Language: English
• Published: MDPI AG 2020-11-01
• Series: Cancers
• Subjects: RMS; PAX3-FOXO1; MIR143-3p; KRAS; NRAS
• Online Access: https://www.mdpi.com/2072-6694/12/11/3312

Rhabdomyosarcoma (RMS) is a soft tissue sarcoma most frequently found in children. In RMS, there are two major subtypes, embryonal RMS (ERMS) and alveolar RMS (ARMS). ARMS has the worse prognosis of the two owing to the formation of the chimeric <i>PAX3–FOXO1</i> gene. A novel therapeutic method is required for treating ARMS. In our previous study, we found that the ectopic expression of chemically modified MIR143-3p#12 (CM-MIR143#12), which is RNase-resistant and shows the highest anti-proliferation activity among the synthesized MIR143 derivatives that were tested, induces significant cell growth suppression by targeting <i>KRAS</i>, <i>AKT</i>, and <i>ERK</i> in colorectal cancer cells. The expression of MIR143-3p in RMS was dramatically downregulated compared with that of normal tissue. Ectopic expression of CM-MIR143#12 in RMS cells resulted in a significant growth inhibitory effect through the induction of apoptosis and autophagy. Interestingly, we found that CM-MIR143#12 also silenced the expression of chimeric <i>PAX3–FOXO1</i> directly and, using siR-KRAS or siR-AKT, that KRAS networks regulated the expression of PAX3–FOXO1 in ARMS cells. In ERMS harboring NRAS mutation, CM-MIR143#12 silenced mutated <i>NRAS</i>. These findings indicate that CM-MIR143#12 efficiently perturbed the RAS signaling pathway, including the ARMS-specific KRAS/PAX3–FOXO1 networks.