Search

[Display omitted] • A DNA tetrahedron linked with the targeting aptamer MUC1 (MUC1-TD) was constructed. • Daunorubicin (DAU) and acridine orange (AO) intercalatively bound to MUC1-TD. • The presence of AO in the ternary system weakened the binding of DAU to MUC1-TD. • The combined DAU and AO had a synergistic cytotoxicity on drug-resistant cells. • The loading of MUC1-TD augmented the cytotoxic effects of DAU and AO. Chemotherapy–phototherapy (CTPT) combination drugs co-loaded by targeted DNA nanostructures can achieve controlled drug delivery, reduce toxic side effects and overcome multidrug resistance. Herein, we constructed and characterized a DNA tetrahedral nanostructure (MUC1-TD) linked with the targeting aptamer MUC1. The interaction of daunorubicin (DAU)/acridine orange (AO) alone and in combination with MUC1-TD and the influence of the interaction on the cytotoxicity of the drugs were evaluated. Potassium ferrocyanide quenching analysis and DNA melting temperature assays were used to demonstrate the intercalative binding of DAU/AO to MUC1-TD. The interactions of DAU and/or AO with MUC1-TD were analyzed by fluorescence spectroscopy and differential scanning calorimetry. The number of binding sites, binding constant, entropy and enthalpy changes of the binding process were obtained. The binding strength and binding sites of DAU were higher than those of AO. The presence of AO in the ternary system weakened the binding of DAU to MUC1-TD. In vitro cytotoxicity studies demonstrated that the loading of MUC1-TD augmented the inhibitory effects of DAU and AO and the synergistic cytotoxic effects of DAU + AO on MCF-7 cells and MCF-7/ADR cells. Cell uptake studies showed that the loading of MUC1-TD was beneficial in promoting the apoptosis of MCF-7/ADR cells due to its enhanced targeting to the nucleus. This study has important guiding significance for the combined application of DAU and AO co-loaded by DNA nanostructures to overcome multidrug resistance. [ABSTRACT FROM AUTHOR]

[Display omitted] • • The binding of mithramycin dimers to DNA nanotrains (AS1411NTrs) was investigated. • • The effect of Mg2+, Zn2+, and Mn2+ on the binding was compared. • • The binding parameters were correlated with drug loading, release and cytotoxicity. • • High drug loading, sustained release and specific targeting were confirmed. Self-assembled DNA nanostructures, as a novel type of nano-biomaterials, are widely used for smart and targeted drug delivery due to their precise structures and versatile functions. The binding affinity of drugs to DNA nanostructures plays an important role in drug loading, release and efficacy. The interaction of mithramycin (MTR) with AS1411-tethered DNA nanotrains (AS1411NTrs) in the presence of different divalent metal ions (Mg2+, Zn2+, and Mn2+) was studied by fluorescence spectroscopy, differential scanning calorimetry and viscosity measurement. The binding mode between the MTR dimers and AS1411NTrs was determined by viscosity experiment and melting temperature measurement. The thermodynamic parameters of the binding process (binding stoichiometry, binding constant, enthalpy change, entropy change and Gibbs free energy change) were determined by fluorescence spectroscopy and differential scanning calorimetry, and the effect of different metal ions on the binding was compared. The release of the MTR dimers loaded by AS1411NTrs in the absence and presence of DNase I was analyzed. The in vitro cytotoxicity of the MTR dimers to HepG2 cancer cells and L02 normal cells and their intracellular uptake efficiency were evaluated. The binding parameters were correlated with the loading, release and cytotoxicity of the MTR dimers. These studies showed that AS1411NTrs had high drug loading and sustained release effect on (MTR) 2 Mg2+, (MTR) 2 Zn2+ and (MTR) 2 Mn2+. This drug loading system improved the lethality to cancer cells and reduced the side effects on normal cells. This study may provide a theoretical basis for the clinical application of MTR loaded by DNA nanostructures. [ABSTRACT FROM AUTHOR]

DNA nanostructures-based chemotherapy-phototherapy (CTPT) combination therapy can achieve targeted release and effectively overcome multidrug resistance (MDR). The therapeutic effect of CTPT combination drugs loaded in DNA nanostructures is related to the interactions among them. Herein, based on our previous research on AS1411NTrs loading with a single drug of DOX, the interactions between a single drug (toluidine blue O, TBO) or combination drugs (doxorubicin and toluidine blue O, DOX + TBO) and AS1411 aptamer-tethered DNA nanotrains (AS1411NTrs) were investigated. By fluorescence spectroscopy and isothermal titration calorimetry technique, the corresponding thermodynamic parameters were obtained, including the number of binding sites, binding constant, enthalpy change and entropy change. By combining with the differential scanning calorimetry and ferrocyanide ion quenching analysis, the binding mode-thermodynamic parameters were correlated. In addition, the effect of the binding affinity of DOX and TBO to AS1411NTrs on the drugs release rate was studied. Finally, the in vitro cytotoxicity and confocal laser scanning microscopy imaging of AS1411NTrs + TBO + DOX was investigated. The results showed that this drug delivery system could increase its in vitro cytotoxicity and overcome drug resistance in DOX-resistant human breast cancer cells (MCF-7/ADR). The work would provide important information for the combination therapy of DOX and TBO to overcome MDR effectively. Unlabelled Image • Doxorubicin (DOX) and toluidine blue O (TBO) were intercalated into DNA nanotrains. • The binding affinity of DOX with DNA nanotrains was stronger than that of TBO. • The addition order of DOX and TBO could affect the stability of DNA nanotrains. • Due to the stronger binding to DNA nanotrains, DOX released more slowly than TBO. • DOX + TBO combination drugs loaded in DNA nanotrains could overcome drug resistance. [ABSTRACT FROM AUTHOR]

• AS1411-DNA nanotrains (AS1411NTrs) were constructed by hybridization chain reaction (HCR). • DOX, EPI and DAU interacted with AS1411NTrs through the intercalative binding mode. • The constructed AS1411NTrs had high drug payload capacity. • The drug release from AS1411NTrs followed first-order release model. • The drug-loaded AS1411NTrs could target to specific cancer cells. As one of the most promising drug delivery carriers, self-assembled DNA nanostructures are characterized of well-defined sizes, excellent biocompatibility, high drug loading and ability to control drug release. Studying the interactions between anticancer drugs and DNA nanostructures can help to associate microstructure-drug loading-release rate-therapeutic effect. Herein AS1411 aptamer-tethered DNA nanotrains (AS1411NTrs) were constructed and used as anthracyclines carrier with high payload for targeted delivery. The bindings of doxorubicin (DOX), epirubicin (EPI), and daunorubicin (DAU) to AS1411NTrs were investigated by isothermal titration calorimetry and fluorescence spectroscopy, and thermodynamic parameters were obtained. The high drug payload capacity of AS1411NTrs was verified by the large number of binding sites (~20). The binding mode was determined by differential scanning calorimetry and potassium iodide (KI) quenching experiments. The release experiment data showed that DNase I facilitated drug release and the release followed the first-order kinetic model. MTT cell viability assay demonstrated that the drug-loaded AS1411NTrs had significantly higher cytotoxicity against target HeLa cells than normal human liver L02 cells. These findings revealed that AS1411NTrs had high payload and targeted release capacity for DOX, EPI, and DAU. This result can provide a theoretical basis for constructing reasonable DNA nanostructures based on drug carriers. Image, graphical abstract [ABSTRACT FROM AUTHOR]