[Progression on Multifunctional Nanoparticles Interfering with Cell Membrane Transporters-associated Drug Resistance].

Multi-drug resistance(MDR)refers to the loss of sensitivity of tumor cells to traditional chemotherapeutics agents under the mediation of various mechanisms,resulting in the reduction of chemotherapy efficacy.Current studies suggest that a variety of factors,including cell membrane transporter-mediated efflux of anti-tumor drugs,special microenvironment in tumor tissue,DNA self-repair and anti-apoptotic process,and epithelial-mesenchymal cell transformation,may contribute to the formation of MDR.Cell membrane transporter-mediated drug efflux refers to an increase in the amount of anti-tumor drug pumped out of the cell through the up-regulation of the ATP-binding cassette transporter on tumor cell membrane,which reduces the concentration of the drug in the cell,thus forming MDR.An effective method to inhibit the efflux pump caused by overexpression of membrane transporters plays an important role in overcoming MDR.As a promising drug delivery system,multifunctional nanoparticles have demonstrated many advantages in antitumor therapy.Meanwhile,nanoparticles with tailored design are capable of overcoming MDR when combined with a variety of strategies.This paper described in detail the studies relevant to the use of multifunctional nano-sized drug delivery system combined with different strategies,such as co-delivery of agents,external responsiveness or target modification for intervention with efflux pump in order to reverse MDR.This paper provides reference for the development of nano-sized drug delivery system and the formulation of reversal strategy in the future.

Targeted delivery of bone mesenchymal stem cells by ultrasound destruction of microbubbles promotes kidney recovery in acute kidney injury.

The aim of the present study was to explore whether ultrasound microbubble destruction augments site-targeted engraftment of bone marrow mesenchymal stem cells (BM-MSCs) to kidney tissue and promotes recovery of the kidney in acute kidney injury (AKI) in rats. AKI was induced by the subcutaneous injection of mercuric chloride (HgCl2). Forty Sprague-Dawley (SD) rats were randomly divided into the following groups after the establishment of rat models of AKI (n = 10): (1) Model group alone (control group); (2) 1.0 W/cm² ultrasound (US) + microbubble (MB) (US/MB group); (3) MSCs group; and (4) 1.0 W/cm² US+MB + MSCs group (US/MB + MSCs group). The number of 4',6-diamidino-2-phenylindole (DAPI) labelled MSCs was evaluated by fluorescence microscopy and real-time polymerase chain reaction (RT-PCR) and Western blotting and histological examination were performed 7 days after MSCs transplantation. It was observed via fluorescence microscopy that the number of DAPI-labelled MSCs in the kidney for the US/MB + MSCs group was significantly more than the MSCs group (p < 0.05). The results from RT-PCR revealed that the US/MB and US/MB + MSCs groups markedly increased the level of inter-cellular adhesion molecule 1 (ICAM-1) messenger ribonucleic acid (mRNA) compared with the control group and the MSCs group (p < 0.05). Western blot analysis showed that the expression of hepatocyte growth factor (HGF) and epidermal growth factor (EGF) in the US/MB + MSCs group were markedly increased compared with the all other groups (p < 0.01). The extent of tubular necrosis and dilation was significantly milder in the US/MB + MSCs group (acoustic exposure conditions: 5s at 1 MHz and 1.0 W/cm² with a 5s pause, totalling 60 s) than the all other groups (p < 0.05). Microbubble destruction by 1.0 W/cm² ultrasound can promote both the homing of BM-MSCs to kidney tissue and the recovery of the kidney in AKI in rats.

The treatment of liver fibrosis induced by hepatocyte growth factor-directed, ultrasound-targeted microbubble destruction in rats.

OBJECTIVE: The purpose of this study was to explore the feasibility of using ultrasound-targeted microbubble destruction to treat liver fibrosis induced by hepatocyte growth factor (HGF). METHODS: Forty Wistar rats were divided into five groups after the models of liver fibrosis were prepared: (1) HGF, ultrasound, and microbubbles (HGF+US/MB); (2) HGF and ultrasound (HGF+US); (3) HGF and microbubbles (HGF+MB); (4) HGF (HGF); and (5) model alone (MA). All rats were killed after being transfected for 14 days. Recovery of the liver was detect by diffusion-weighted imaging (DWI) and pathological methods. Collagen I expression was detected by immunohistochemistry. Hepatocyte growth factor expression in the liver was detect by western blotting. RESULTS: The results of DWI and pathological examination showed the recovery of liver in HGF+US/MB group were better than those of other groups. In HGF+US/MB group, collagen I expression was less, and HGF protein was the highest among all the groups. CONCLUSIONS: Ultrasound-targeted microbubble destruction could deliver HGF into the fibrotic liver and produce an antifibrosis effect, which could provide a novel strategy for gene therapy of liver fibrosis.

Transfection efficiency of TDL compound in HUVEC enhanced by ultrasound-targeted microbubble destruction.

The aim of the present study was to explore the gene transfection efficiency of Tat peptide/plasmid DNA/ liposome (TDL) compound combined with ultrasound-targeted microbubble destruction (UTMD) in human umbilical vein endothelial cell (HUVEC). Tat peptide, plasmid DNA (pIRES2-EGFP-HGF) and Lipofectamine 2000 were used to prepare the TDL compound. Microbubbles were prepared using mechanic vibration. The expression of the report gene enhanced green fluorescent protein (EGFP) was observed using fluorescent microscopy and flow cytometry. The viability of HUVEC was measured by MTT assay. mRNA and protein of HGF was analyzed by reverse transcription-polymerase chain reaction and Western Blot. The intensity of green fluorescence and the gene transfection efficiency of TDL compound + microbubbles + ultrasound group were higher than those of other groups, and no significantly different viability was found between TDL compound + microbubbles + ultrasound group and the other groups. The HGF mRNA and HGF protein of TDL compound + microbubbles + ultrasound group were higher than those of other groups. Our finding demonstrated that UTMD could enhance the transfection efficiency of TDL compound without obvious effects on the cell viability of HUVEC, suggesting that the combination of UTMD and TDL compound might be a useful tool for the gene therapy of ischemic heart disease.

[Therapeutic angiogenesis induced by hepatocyte growth factor directed by ultrasound-targeted microbubble destruction].

OBJECTIVE: To explore the feasibility of therapeutic angiogenesis in myocardial infarction induced by hepatocyte growth factor (HGF) mediated by ultrasound-targeted microbubble destruction. METHODS: Forty Wistar rats were divided into 4 groups after the models of myocardial infarction were established: HGF + ultrasound + microbubble (HGF + US/MB) groups, HGF and ultrasound (HGF + US) group, HGF and microbubble (HGF + MB) group, and surgery alone (SA) group. Ultrasound-targeted destruction microbubble loaded with HGF gene with ECG trigger was performed in HGF + US group. Microbubble loaded with HGF gene was infused intravenously in HGF + MB group, and normal saline were infused in SA group. All rats were killed 14 days after transfection. The CD34 expression was detected by immunohistochemistry (IHC), and microvessel density (MVD) was counted in high power field. The HGF expression on myocardium was detected by ELISA, and the correlation between the contents of HGF and MVD in myocardium was analyzed. RESULTS: IHC results showed that CD34 expressions, shown as brown granules, were located on the membrane and endochylema of vascular endothelial cells. The MVD in HGF + US/MB group [ (266.9 +/- 39.8) /HPF] were highest among all the groups. The contents of HGF in myocardium were highest in HGF + US/MB group [(5.54 +/- 0.81) ng/g], and the contents of HGF in anterior wall were significantly higher than those in posterior wall (P < 0.05); the difference was also significant when compared with others groups (P < 0.01). The correlation analysis showed the contents of HGF was positively correlated with MVD in myocardium. CONCLUSION: Ultrasound-targeted microbubble destruction can effectively deliver HGF into the infracted myocardium and facilitate angiogenesis, which provides a novel way in the gene therapy of myocardial infarction.