Browsing by Author "Varas, Manuel"

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    Angiotensin-(1-9) regulates cardiac hypertrophy in vivo and in vitro
    (LIPPINCOTT WILLIAMS & WILKINS, 2010) Paz Ocaranza, Maria; Lavandero, Sergio; Jalil, Jorge E.; Moya, Jaqueline; Pinto, Melissa; Novoa, Ulises; Apablaza, Felipe; Gonzalez, Leticia; Hernandez, Carol; Varas, Manuel; Lopez, Rene; Godoy, Ivan; Verdejo, Hugo; Chiong, Mario
    Background Angiotensin-(1-9) is present in human and rat plasma and its circulating levels increased early after myocardial infarction or in animals treated with angiotensin-converting enzyme inhibitor. However, the cardiovascular effects of this peptide are unknown.
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    Enalapril attenuates downregulation of angiotensin-converting enzyme 2 in the late phase of ventricular dysfunction in myocardial infarcted rat
    (LIPPINCOTT WILLIAMS & WILKINS, 2006) Ocaranza, Maria Paz; Godoy, Ivan; Jalil, Jorge E.; Varas, Manuel; Collantes, Patricia; Pinto, Melissa; Roman, Maritza; Ramirez, Cristian; Copaja, Miguel; Diaz Araya, Guillermo; Castro, Pablo; Lavandero, Sergio
    The early and long-term effects of coronary artery ligation on the plasma and left ventricular angiotensin-converting enzyme (ACE and ACE2) activities, ACE and ACE2 mRNA levels, circulating angiotensin (Ang) levels [Ang I, Ang-(1-7), Ang-(1-9), and Ang II], and cardiac function were evaluated 1 and 8 weeks after experimental myocardial infarction in adult Sprague Dawley rats. Sham-operated rats were used as controls. Coronary artery ligation caused myocardial infarction, hypertrophy, and dysfunction 8 weeks after surgery. At week 1, circulating Ang II and Ang-(1-9) levels as well as left ventricular and plasma ACE and ACE2 activities increased in myocardial-infarcted rats as compared with controls. At 8 weeks post-myocardial infarction, circulating ACE activity, ACE mRNA levels, and Ang II levels remained higher, but plasma and left ventricular ACE2 activities and mRNA levels and circulating levels of Ang-(1-9) were lower than in controls. No changes in plasma Ang-(1-7) levels were observed at any time. Enalapril prevented cardiac hypertrophy and dysfunction as well as the changes in left ventricular ACE, left ventricular and plasmatic ACE2, and circulating levels of Ang II and Ang-(1-9) after 8 weeks postinfafction. Thus, the decrease in ACE2 expression and activity and circulating Ang-(1-9) levels in late ventricular dysfunction post-myocardial infarction were prevented with enalapril. These findings suggest that in this second arm of the renin-angiotensin system, ACE2 may act through Ang-(1-9), rather than Ang-(1-7), as a counterregulator of the first arm, where ACE catalyzes the formation of Ang II.
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    Targeting antisense mitochondrial ncRNAs inhibits murine melanoma tumor growth and metastasis through reduction in survival and invasion factors
    (IMPACT JOURNALS LLC, 2016) Lobos Gonzalez, Lorena; Silva, Veronica; Araya, Mariela; Restovic, Franko; Echenique, Javiera; Oliveira Cruz, Luciana; Fitzpatrick, Christopher; Briones, Macarena; Villegas, Jaime; Villota, Claudio; Vidaurre, Soledad; Borgna, Vincenzo; Socias, Miguel; Valenzuela, Sebastian; Lopez, Constanza; Socias, Teresa; Varas, Manuel; Diaz, Jorge; Burzio, Luis O.; Burzio, Veronica A.
    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.