Synthetic Dna Nanomaterials For Drug Delivery And 3D Cell Culture

Interest in the use of DNA nanotechnology in biomedical applications has increased tremendously in the last decade due to the uniqueness of DNA properties that allow precise and predictable construction of synthetic DNA building blocks, which later form higher complex DNA structures. Moreover, the synthetic DNA structures can be manipulated by the same molecular toolkits as natural DNA and naturally degraded to metabolite by-products. Thus far, most of the biomedical applications employing DNA nanomaterials are related to gene delivery and detection due to Watson-Crick base pairing rules. For example, the DNA nanostructures have been used in detecting DNA and RNA in biological systems by an innate hybridization property between the DNA nanostructures and target oligonucleotides. Moreover, the DNA nanostructures have been used as a carrier for antisense DNA or siRNA. Here, we present the use of synthetic branched DNA nanomaterials for a co-delivery of Doxorubicin and siRNA and a hydrogel-based scaffold for 3D cell culture. First, we demonstrate the development of the novel DNA-lipid co-delivery nanocarriers called DNAsomes. The DNAsomes can be loaded with both siRNA and hydrophobic drugs that promote synergistic effects. The DNAsomes exhibit lower doses of drugs required for therapy. Furthermore, we propose a novel DNA hydrogel-based scaffold for 3D cell culture. Cells grow, proliferate, and form multicellular spheroids (MCS) inside the DNA hydrogels. The DNA hydrogels are naturally degraded by effects of FBS in the culture media and by-products secreted from the cells. In addition, the DNA hydrogels can be degraded on-demand by a DNase I enzymatic reaction to release cultured MCS without any disruption to the MCS. Also, re-encapsulation of released MCS is possible allowing several downstream applications of the MCS. Lastly, we demonstrate the potential use of DNA hydrogels for 3D siRNA delivery. The siRNA hybridize to the DNA building blocks forming siRNA hydrogels. The time-specific release of siRNA can occur in the presence of RNase H only degrading RNA/DNA hybrids bridging the DNA hydrogels and siRNA. By adding different amount of RNase H, the siRNA controlled release profiles are different. The siRNA hydrogels can potentially be used to culture and transfect the MCS at the same time

Purification and identification of novel antioxidant peptides derived from Bombyx mori pupae hydrolysates

The biological importance of antioxidant peptides was the focus of new natural sources of food preservatives. Bombyx mori pupae are considered a valuable by-product of the silk-reeling industry due to their high-quality protein content. This study aimed to purify and identify the antioxidant peptides obtained from enzymatically hydrolyzed B. mori pupae, which could be used as new sources of natural food preservatives. Among the prepared hydrolysates, pepsin hydrolysate with the highest antioxidant activities was purified sequentially using ultrafiltration and reversed-phase high-performance liquid chromatography (RP-HPLC). The DPPH radical scavenging and ferrous ion chelating activity were used to evaluate antioxidant activity. Fractions with high activity were further analyzed by liquid chromatography-tandem mass spectrometry (LC–MS/MS). Three peptides were identified as Glu-Asn-Ile-Ile-Leu-Phe-Arg (ENIILFR), Leu-Asn-Lys-Asp-Leu-Met-Arg (LNKDLMR), and Met-Leu-Ile-Ile-Ile-Met-Arg (MLIIIMR), respectively. All three novel identified peptides exhibited significantly stronger antioxidant capacity than synthetic antioxidants used in the food industry, including butylated hydroxyanisole (BHA), and butylated hydroxytoluene (BHT). ENIILFR showed the best antioxidant activity. These findings indicate that the three peptides have potential applications as natural antioxidants in the food industry

Baicalein Inhibits Metastatic Phenotypes in Nasopharyngeal Carcinoma Cells via a Focal Adhesion Protein Integrin β8

Baicalein, a prominent flavonoid from the indigenous herbal plant Scutellaria baicalensis Georgi, possesses broad-spectrum anticancer activities. However, the biological effects of baicalein on nasopharyngeal carcinoma (NPC) and its underlying mechanisms remain unclarified. Thus, in this study, we examined the effects of baicalein on NPC cell lines and investigated the corresponding molecular mechanism through transcriptome profiling. In the study, four NPC cell lines were treated with various concentrations of baicalein at different time points. Cellular toxicity and proliferative inhibition of baicalein were examined by MTT assay. Metastatic phenotypes of NPC cells were investigated by wound healing, transwell, and adhesion assays. Additionally, microarray experiments were performed to determine the cellular pathways affected by baicalein. The expression and localization of the integrin β8 were validated by western immunoblotting and immunofluorescence. Our results revealed that baicalein exhibited its cytotoxicity and antiproliferative activity on all tested NPC cell lines. It also significantly inhibited metastatic phenotypes at sub-lethal concentrations. Transcriptomic analysis showed that baicalein significantly affected the focal adhesion pathway in NPC, where integrin β8 was greatly diminished. Thus, the present study results suggested that baicalein inhibits the metastatic phenotypes of NPC cells by modulating integrin β8, one of the major molecules in a focal adhesion pathway