Research on the Inhibitory Effect of Doxorubicin-loaded Liposomes Targeting GFAP for Glioma Cells.

BACKGROUND: Glioma is the most common and devastating brain tumor. In recent years, doxorubicin (DOX) is one of the drugs used in the treatment of gliomas, but it has side effects and poor clinical outcomes. Therefore, the delivery of drugs to the tumor site by targeted transport is a new approach to tumor treatment. OBJECTIVE: This study focuses on the anti-tumor effects of GFAP-modified drug-carrying liposomes loaded with DOX (GFAP-DOX-LPs) on gliomas. METHODS: GFAP-DOX-LPs were prepared by solvent evaporation method. After characterization analysis of GFAP-DOX-LPs, the encapsulation efficiency, the drug loading capacity and in vitro release performance were determined. Then, the MTT method was used to investigate the cytotoxicity and proliferative behavior of U251 and U87 cell lines. After that, flow cytometry was used to investigate the effect of the drug administration group on tumor cell apoptosis. Eventually, the anti-tumor activity was tested in vivo. RESULTS: The average particle size of GFAP-DOX-LPs was determined to be 116.3 ± 6.2 nm, and the average potential was displayed as 22.8 ± 7.2 mv. Besides, the morphology of the particle indicated a spherical shape. The encapsulation rate and drug loading were calculated and determined, which were 91.84 ± 0.41% and 9.27 ± 0.55%. In an acidic medium, the DOX release rate reached about 87%. GFAP-DOX-LPs could target glioma cells with low cytotoxicity and inhibit glioma cell proliferation with high efficiency, resulting in promoting apoptosis. The anti-tumor effect of GFAP-DOX-LPs was significantly enhanced. At the same time, the number of GFAPpositive cells in tumor tissues was significantly lower after treatment. Therefore, the overall survival time could be significantly prolonged. CONCLUSION: The prepared GFAP-DOX-LPs had good targeting and glioma cell inhibition ability. This demonstrated the promising application of the prepared liposomes in tumor targeting, especially in the field of targeted drug delivery for the treatment of brain tumor.

A non-cationic nucleic acid nanogel for the delivery of the CRISPR/Cas9 gene editing tool.

Herein, we report a non-cationic DNA-crosslinked nanogel for intracellular delivery of a Cas9 and single guide RNA (Cas9/sgRNA) complex. A DNA-grafted polycaprolactone brush (DNA-g-PCL) is first loaded with the Cas9/sgRNA complex and then crosslinked by DNA linkers via nucleic acid hybridization to form a nanosized hydrogel, in which the gene editing tools are embedded and protected inside. With compact architecture, the Cas9/sgRNA complex-containing nanogel exhibited excellent physiological stability against nuclease digestion and enhanced cellular uptake efficiency, making the delivery system a promising tool for target genome editing.

pH-Responsive and Gemcitabine-Containing DNA Nanogel To Facilitate the Chemodrug Delivery.

Herein, we construct a structure-switchable gemcitabine (Ge)-containing DNA nanogel that can respond to the intracellular acidic environment, subsequently facilitating the chemodrug release inside the cells. Based on the structural similarity between Ge and deoxycytidine (dC), dC nucleotides in the component DNA strands used for nanogel assembly are fully replaced by Ge during their synthesis. By changing the designed sequences, two Ge-containing Y-shaped motifs with different sticky ends are first assembled and then associated together to form nanogel by sticky-end hybridizations. In particular, one of the sticky-end sequences is arbitrarily designed to be rich of Ge and the other is designed to be partially complementary to the first Ge-rich sticky end. At the neutral or basic condition, the Ge-rich sticky ends hybridize with the partially complementary sticky ends on the second Y motifs, keeping the assembled nanogel stable. Upon being exposed to the acidic condition, Ge-rich sticky ends intend to form intramolecular i-motif-like quadruplex structures, resulting in the disassembly of the nanogel. On the one hand, the nanosized feature enables the Ge-containing nanogel with rapid cellular uptake behavior. On the other hand, the pH-responsive feature endows the rapid disassembly of the nanogel to facilitate the enzymatic drug release inside the cell, resulting in the enhanced anticancer activity of the DNA-based drug delivery system.