Browsing by Author "Villota, Claudio"
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Item Mitochondrial ncRNA targeting induces cell cycle arrest and tumor growth inhibition of MDA-MB-231 breast cancer cells through reduction of key cell cycle progression factors(2019) Fitzpatrick, Christopher; Bendek, Maximiliano F.; Briones, Macarena; Farfán, Nicole; Silva, Valeria A.; Nardocci, Gino; Montecino, Martín; Boland, Anne; Deleuze, Jean-Francois; Villegas, Jaime; Villota, Claudio; Silva, Verónica; Lobos-González, Lorena; Borgna, Vincenzo; Barrey, Eric; Burzio, Luis O.; Burzio, Verónica A.The family of long noncoding mitochondrial RNAs (ncmtRNAs), comprising sense (SncmtRNA), and antisense (ASncmtRNA-1 and ASncmtRNA-2) members, are differentially expressed according to cell proliferative status; SncmtRNA is expressed in all proliferating cells, while ASncmtRNAs are expressed in normal proliferating cells, but is downregulated in tumor cells. ASncmtRNA knockdown with an antisense oligonucleotide induces massive apoptosis in tumor cell lines, without affecting healthy cells. Apoptotic death is preceded by proliferation blockage, suggesting that these transcripts are involved in cell cycle regulation. Here, we show that ASncmtRNA knockdown induces cell death preceded by proliferative blockage in three different human breast cancer cell lines. This effect is mediated by downregulation of the key cell cycle progression factors cyclin B1, cyclin D1, CDK1, CDK4, and survivin, the latter also constituting an essential inhibitor of apoptosis, underlying additionally the onset of apoptosis. The treatment also induces an increase in the microRNA hsa-miR-4485-3p, whose sequence maps to ASncmtRNA-2 and transfection of MDA-MB-231 cells with a mimic of this miRNA induces cyclin B1 and D1 downregulation. Other miRNAs that are upregulated include nuclear-encoded hsa-miR-5096 and hsa-miR-3609, whose mimics downregulate CDK1. Our results suggest that ASncmtRNA targeting blocks tumor cell proliferation through reduction of essential cell cycle proteins, mediated by mitochondrial and nuclear miRNAs. This work adds to the elucidation of the molecular mechanisms behind cell cycle arrest preceding tumor cell apoptosis induced by ASncmtRNA knockdown. As proof-of-concept, we show that in vivo knockdown of ASncmtRNAs results in drastic inhibition of tumor growth in a xenograft model of MDA-MB-231 subcutaneous tumors, further supporting this approach for the development of new therapeutic strategies against breast cancer.Item Targeting antisense mitochondrial noncoding RNAs induces bladder cancer cell death and inhibition of tumor growth through reduction of survival and invasion factors.(Ivyspring International Publisher, 2020) Borgna, Vincenzo; Lobos-González, Lorena; Guevara, Francisca; Landerer, Eduardo; Bendek, Maximiliano; Ávila, Rodolfo; Silva, Verónica; Villota, Claudio; Araya, Mariela; Rivas, Alexis; López, Constanza; Socías, Teresa; Castillo, Jorge; Alarcón, Luis; Burzio, Luis; Burzio, Verónica; Villegas, JaimeKnockdown of the antisense noncoding mitochondrial RNAs (ASncmtRNAs) induces apoptotic death of several human tumor cell lines, but not normal cells, supporting a selective therapy against different types of cancer. In this work, we evaluated the effects of knockdown of ASncmtRNAs on bladder cancer (BCa). We transfected the BCa cell lines UMUC-3, RT4 and T24 with the specific antisense oligonucleotide Andes-1537S, targeted to the human ASncmtRNAs. Knockdown induced a strong inhibition of cell proliferation and increase in cell death in all three cell lines. As observed in UMUC-3 cells, the treatment triggered apoptosis, evidenced by loss of mitochondrial membrane potential and Annexin V staining, along with activation of procaspase-3 and downregulation of the anti-apoptotic factors survivin and Bcl-xL. Treatment also inhibited cell invasion and spheroid formation together with inhibition of N-cadherin and MMP 11. In vivo treatment of subcutaneous xenograft UMUC-3 tumors in NOD/SCID mice with Andes-1537S induced inhibition of tumor growth as compared to saline control. Similarly, treatment of a high-grade bladder cancer PDX with Andes-1537S resulted in a strong inhibition of tumor growth. Our results suggest that ASncmtRNAs could be potent targets for bladder cancer as adjuvant therapy.