Targeting antisense mitochondrial ncRNAs inhibits murine melanoma tumor growth and metastasis through reduction in survival and invasion factors.

// Lorena Lobos-Gonzalez 1, 2, 3 , Veronica Silva 1, 2 , Mariela Araya 1, 2 , Franko Restovic 1, 2, 8 , Javiera Echenique 1, 2 , Luciana Oliveira-Cruz 1, 2 , Christopher Fitzpatrick 1, 2, 4 , Macarena Briones 1, 2 , Jaime Villegas 1, 2, 4 , Claudio Villota 1, 2, 4 , Soledad Vidaurre 1, 5 , Vincenzo Borgna 1, 2, 6 , Miguel Socias 7 , Sebastian Valenzuela 2 , Constanza Lopez 1, 2 , Teresa Socias 1, 2 , Manuel Varas 2 , Jorge Diaz 3 , Luis O. Burzio 1, 2, 4 , Veronica A. Burzio 1, 2, 4 1 Andes Biotechnologies SpA, Santiago, Chile 2 Fundacion Ciencia & Vida, Santiago, Chile 3 Facultad de Medicina, Universidad de Chile, Independencia, Santiago, Chile 4 Facultad de Ciencias Biologicas, Universidad Andres Bello, Republica, Santiago, Chile 5 Facultad de Salud, Deporte y Recreacion, Universidad Bernardo O’Higgins, Santiago, Chile 6 Servicio de Urologia, Hospital Barros-Lucco-Trudeau, Santiago, Chile 7 Clinica Alemana, Santiago, Chile 8 Present address: Facultad de Ciencias Biologicas, Pontificia Universidad Catolica de Chile, Santiago, Chile Correspondence to: Veronica A. Burzio, email: vburzio@gmail.com Luis O. Burzio, email: lburzio@gmail.com Keywords: mitochondria, noncoding RNA, melanoma, metastasis, antisense therapy Received: May 02, 2016     Accepted: July 19, 2016     Published: August 06, 2016 ABSTRACT We reported that knockdown of the antisense noncoding mitochondrial RNAs (ASncmtRNAs) induces apoptotic death of several human tumor cell lines, but not normal cells, suggesting this approach for selective therapy against different types of cancer. In order to translate these results to a preclinical scenario, we characterized the murine noncoding mitochondrial RNAs (ncmtRNAs) and performed in vivo knockdown in syngeneic murine melanoma models. Mouse ncmtRNAs display structures similar to the human counterparts, including long double-stranded regions arising from the presence of inverted repeats. Knockdown of ASncmtRNAs with specific antisense oligonucleotides (ASO) reduces murine melanoma B16F10 cell proliferation and induces apoptosis in vitro through downregulation of pro-survival and metastasis markers, particularly survivin. For in vivo studies, subcutaneous B16F10 melanoma tumors in C57BL/6 mice were treated systemically with specific and control antisense oligonucleotides (ASO). For metastasis studies, tumors were resected, followed by systemic administration of ASOs and the presence of metastatic nodules in lungs and liver was assessed. Treatment with specific ASO inhibited tumor growth and metastasis after primary tumor resection. In a metastasis-only assay, mice inoculated intravenously with cells and treated with the same ASO displayed reduced number and size of melanoma nodules in the lungs, compared to controls. Our results suggest that ASncmtRNAs could be potent targets for melanoma therapy. To our knowledge, the ASncmtRNAs are the first potential non-nuclear targets for melanoma therapy.