RESUMO
Herein, by directly introducing mismatched reactant DNA, high-reactivity and high-threshold enzyme-free target recycling amplification (EFTRA) is explored. The developed high-efficiency EFTRA (HEEFTRA) was applied as a programmable DNA signal converter, possessing higher conversion efficiency than the traditional one with perfect complement owing to the more negative reaction standard free energy (ΔG). Once traces of input target miRNA interact with the mismatched reactant DNA, amounts of ferrocene (Fc)-labeled output DNA could be converted via the EFTRA. Impressively, the Fc-labeled output DNA could be easily captured by the DNA tetrahedron nanoprobes (DTNPs) on the electrode surface to form triplex-forming oligonucleotide (TFO) at pH = 7.0 for sensitive electrochemical signal generation and the DTNPs could be regenerated at pH = 10.0, from which the conversion efficiency (N) will be accurately obtained, benefiting the selection of suitable mismatched bases to obtain high-efficiency EFTRA (HEEFTRA). As a proof of concept, the HEEFTRA as an evolved DNA signal converter is successfully applied for the ultrasensitive detection of miRNA-21, which gives impetus to the design of other signal converters with excellent efficiency for ultimate applications in sensing analysis, clinical diagnosis, and other areas.
RESUMO
Breast cancer is the most common cancer among women worldwide. Chemoresistance remains to be a considerable obstacle in breast cancer therapy and it is often involves dysregulation of a variety of microRNAs (miRNAs). miR-485-5p functions as a tumor suppressor in several types of human cancers. However, its role in breast cancer chemosensitivity have not been determined. In the present study, we demonstrated that overexpression of miR-485-5p suppresses breast cancer progression and enhances chemosensitivity both in vitro and in vivo. Further study demonstrated that miR-485-5p directly targeted the 3'-untranslated region of survivin and overexpression of survivin overcomes the miR-485-5p induced effects on breast cancer. In conclusion, our study identified that miR-485-5p suppresses cancer progression and enhances the chemosensitivity by targeting survivin. Targeting survivin by miR-485-5p may provide a potential approach to reverse chemosensitivity in breast cancer cells.
Assuntos
Neoplasias da Mama/genética , Neoplasias da Mama/terapia , Proteínas Inibidoras de Apoptose/antagonistas & inibidores , MicroRNAs/genética , MicroRNAs/uso terapêutico , Regiões 3' não Traduzidas , Animais , Neoplasias da Mama/metabolismo , Linhagem Celular Tumoral , Proliferação de Células/genética , Progressão da Doença , Resistencia a Medicamentos Antineoplásicos/genética , Feminino , Regulação Neoplásica da Expressão Gênica , Marcação de Genes , Genes Supressores de Tumor , Humanos , Proteínas Inibidoras de Apoptose/genética , Proteínas Inibidoras de Apoptose/metabolismo , Células MCF-7 , Camundongos , Camundongos SCID , Invasividade Neoplásica/genética , Survivina , Regulação para Cima , Ensaios Antitumorais Modelo de XenoenxertoRESUMO
BACKGROUND: Breast cancer is the most common cancer among women worldwide and metastasis is the leading cause of death among patients with breast cancer. The transforming growth factor-ß (TGF-ß) pathway plays critical roles during breast cancer epithelial-mesenchymal transition (EMT) and metastasis. SMAD2, a positive regulator of TGF-ß signaling, promotes breast cancer metastasis through induction of EMT. METHODS: The expression of miR-190 and SMAD2 in breast cancer tissues, adjacent normal breast tissues and cell lines were determined by RT-qPCR. The protein expression levels and localization were analyzed by western blotting and immunofluorescence. ChIP and dual-luciferase report assays were used to validate the regulation of ZEB1-miR-190-SMAD2 axis. The effect of miR-190 on breast cancer progression was investigated both in vitro and in vivo. RESULTS: miR-190 down-regulation is required for TGF-ß-induced EMT. miR-190 suppresses breast cancer metastasis both in vitro and in vivo by targeting SMAD2. miR-190 expression is down-regulated and inversely correlates with SMAD2 in breast cancer samples, and its expression level was associated with outcome in patients with breast cancer. Furthermore, miR-190 is transcriptionally regulated by ZEB1. CONCLUSIONS: Our data uncover the ZEB1-miR-190-SMAD2 axis and provide a mechanism to explain the TGF-ß network in breast cancer metastasis.
