Yanfang Yang

Dual-modified liposomes with a two-photon-sensitive cell penetrating peptide and NGR ligand for siRNA targeting delivery.

Tumor-oriented nanocarrier drug delivery approaches with photosensitivity have drawn considerable attention over the years. However, due to its low penetrability and ability to harm tissues, the use of UV light for triggered nanocarrier release in in vivo applications has been limited. Compared with UV light, near-infrared (NIR) light deeply penetrates tissues and is less damaging to cells. In this study, we devised and tested a strategy for functional siRNA delivery to cells by loading siRNA into cationic liposomes bearing a photolabile-caged cell-penetrating peptide (pcCPP) and asparagine-glycine-arginine peptide (NGR) molecules attached to the liposome surface (pcCPP/NGR-LP). Here, the positive charges of the lysine residues on the CPP were temporarily caged by the photosensitive group (PG), neutralizing its charges and thereby forming a pcCPP. This event subsequently led to conditional NIR light-dependent cell-penetrating functionality. After administration, the pcCPP/NRG-LP was inactivated in the circulatory system as it could not penetrate the tumor cell membrane. The NGR moiety selectively bound to CD13-positive tumors, which facilitated the active accumulation of pcCPP/NGR-LP in tumor tissues. Then, upon illumination using NIR light at the tumor site, the PG was uncaged, the interaction of the CPP with the cell membrane was restored and the activated dual-modified liposomes exhibited enhanced tumor cellular uptake and selectivity due to the synergistic effect of CPP-mediated cellular entry and NGR-mediated endocytosis. Subsequent research demonstrated that the pcCPP/NGR-LP showed good physicochemical properties, effective cellular uptake, endosomal escape and significant gene silencing in HT-1080 cells in vitro. Additionally, after systemic administration in mice, pcCPP/NGR-LP accumulated in the tumor, augmented c-myc silencing and delayed tumor progression. In conclusion, the combined application of these pcCPP and NGR modifications may provide a reasonable approach for the selectively targeted delivery of siRNA.

A novel subcutaneous infusion delivery system based on osmotic pump: in vitro and in vivo evaluation

Abstract An economical, convenient portable drug delivery system combining osmotic pump with subcutaneous infusion was developed, which was composed of three primary components: water chamber, osmotic pump chamber and support base. Ceftriaxone sodium (CRO) was selected as the model drug and osmotic pump tablets were prepared. The influence of osmotic agents on drug release profiles was evaluated. As the adjustment made by the osmotic agents was limited, the compositions of semipermeable membrane were investigated to determine significant associations of factors based on orthogonal design. The in vitro release profiles of the optimum formulation achieved to the predetermined value (15 ± 3 min for the initial release time Ti and 5.75 ± 0.25 h for the extent release time Te). The pharmacokinetic profiles of this drug delivery system were evaluated in Beagle dogs. In vivo results demonstrated that the osmotic pump subcutaneous infusion administration was equivalent to intravenous injection administration in terms of bioavailability. Moreover, constant drug plasma levels with minimized fluctuations could be achieved with this osmotic pump subcutaneous infusion system, compared with intravenous injection.

A photo-responsive peptide- and asparagine–glycine–arginine (NGR) peptide-mediated liposomal delivery system

Abstract The conjugation of tunable peptides or materials with nanocarriers represents a promising approach for drug delivery to tumor cells. In this study, we report the development of a novel liposomal carrier system that exploits the cell surface binding synergism between photo-sensitive peptides (PSPs) and targeting ligands. The positive charges of the lysine residues on the cell-penetrating peptides (CPPs) were temporarily caged by the photolabile-protective groups (PG), thereby forming a PSP. Furthermore, this PSP enhances specific uptake into cancer cells after rapidly uncaging the PG via near-infrared (NIR) light illumination. In the circulatory system, the cell penetrability of PSP was hindered. In contrast, the asparagine–glycine–arginine (NGR) peptide moieties, selectively bind to CD13-positive tumors, were attached to the nanocarrier to facilitate the active accumulation of this liposomal carrier in tumor tissue. The dual-modified liposomes (PSP/NGR-L) were prepared by emulsification method, and the concentrations of DSPE-PEG2000-psCPP and DSPE-PEG5000-NGR in the liposomes were chosen to be 4% and 1% (molar ratio), respectively. The mean particle size of the PSP/NGR-L was about 95 nm, and the drug entrapment efficiency was more than 90%. Cellular uptake results demonstrated that the proposed PSP/NGR-L had an enhancement of cancer cell recognition and specific uptake. Furthermore, the PSP/NGR-L demonstrated a stronger antitumor efficacy in the HT-1080 tumor model in nude mice with the aid of NIR illumination.

Preparation, Characterization, and Pharmacodynamics of Thermosensitive Liposomes Containing Docetaxel

A novel thermosensitive liposome (TL) containing docetaxel (DTX) was designed to enhance DTX-targeted delivery and antitumor effect. TL loading DTX (DTX-TL) were prepared by thin film hydration. The mean particle size of the liposomes was about 100 nm, and the drug entrapment efficiency was more than 95%. The phase transition temperature of liposomes was about 42 °C. In vitro drug release showed that drug released at 37 °C was obviously less than that at 42 °C. For in vivo experiments, the human breast tumor model was established by subcutaneous xenotransplantation on nude mice; liposomes and injection containing DTX were injected i.v. in nude mice, followed by exposure of the tumors to hyperthermia (HT) for 30 min after administration. The tumor inhibition ratio of DTX-TL group was significantly higher than the normal injection group. Combining TL with HT enhanced the delivery of DTX and thereby its antitumor effects. The liposomes reported in this paper could potentially produce viable clinical strategies for improved targeting and delivery of DTX for the treatment of breast cancer.

Preparation and characterization of photo-responsive cell-penetrating peptide-mediated nanostructured lipid carrier

Abstract Tumor-oriented nanocarrier drug delivery approaches with photo-sensitivity have been drawing considerable attention over the years. Here we described a nanostructured lipid carrier (NLC) modified with photo-responsive cell-penetrating peptides (pCPP-NLC). The conventional cell penetrating peptide (CPP)-mediated intracellular drug delivery system sometimes seemed limited due to the lack of target selectivity of the cell penetrating activity. In this study, pCPP (CKRRMKNvocWKNvo0cKNvoc), a photo-responsive CPP originated from the CPP (CKRRMKWKK), was endowed photo-responsiveness after masking of lysines in the sequence of CPP with photolabile-protective groups, and was introduced onto the surface of NLC. Accordingly, upon reaching the tumor tissues, pCPP-NLC enhance specific cancer cellular uptake after rapidly cleaving the photolabile-protective group, in this case, illumination in the presence of UV-light. In contrast, in circulation, the penetration was shielded. The pCPP-NLC carrying paclitaxel (PTX) prepared in this work possessed suitable physiochemical properties such as small particle size, high drug encapsulation efficiency, and good stability. The strong cellular uptake and cytotoxic activity of pCPP-NLC in HT-1080 cells verified the correlation with illumination. The remarkable penetration into HT-1080 multicellular tumor spheroids confirmed that the temporary mask of the photolabile-protective group in pCPP does not disturb the penetration ability of CPP in the tumor microenvironment with illumination. Furthermore, the triggered activation exhibited higher antitumor efficacy with the tumor spheroids compared with the non-modified NLC (N-NLC) and Taxol®. In conclusion, the application of pCPP modifications may be an approach for the selectively targeted delivery of anti-tumor agents.

Ultrasound-responsive nanobubbles contained with peptide-camptothecin conjugates for targeted drug delivery.

Abstract To improve the targeting delivery efficiency of anticancer drug to tumor sites, a new strategy combining cell-permeable peptide (CPP) and ultrasound was reported in this article. In this study, we devised and tested a strategy for functional payload delivery to cells by loading CPP–camptothecin conjugate (CPP–CPT) into nanobubble (CPP–CPT NB). Here, CPP existing in the conjugation form of CPP and CPT was hidden in nanobubble to cloak the penetration activity of CPP. Meanwhile, local tumor ultrasound was utilized to achieve specific targeting of CPP–CPT to the tumor cells. The mean particle size of the prepared CPP–CPT NB was ∼200 nm, and the drug entrapment efficiency was >80%. Stimulated by ultrasound, over 90% of the entrapped CPP–CPTs would release from the nanobubbles. Subsequent research demonstrated that the CPP–CPT NB showed effective cellular uptake and significant cytotoxic activity in HeLa cells in vitro. Additionally, after systemic administration in mice, CPP–CPT NB with ultrasound showed a higher tumor inhibition effect in nude mice xenografted HeLa cells tumors and excellent body safety when compared with normal CPT injection group. In conclusion, the carrier constructed in this study would be a safe and efficiently drug delivery system for specific cancer treatment.

Polymer Nanoparticles Modified with Photo- and pH-Dual-Responsive Polypeptides for Enhanced and Targeted Cancer Therapy.

The cationic nature of cell penetrating peptides (CPPs) and their absence of cell selectivity restrains their applications in vivo. In this work, polymer nanoparticles (NPs) modified with photo- and pH-responsive polypeptides (PPPs) were successfully developed and respond to near-infrared (NIR) light illumination at the tumor site and a lowered tumor extracellular pH (pHe). In PPPs, the internalization function of CPPs (positively charged) is quenched by a pH-sensitive inhibitory peptide (negatively charged), which is linked via a photocleavable group. Small interfering RNA (siRNA) was loaded into NPs by a double-emulsion technique. In vivo experiments included siRNA loading, cellular uptake, cell apoptosis, siRNA transfection, tumor targeting delivery, and the in vivo antitumor efficacy. Results showed that the prepared PPP-NPs could selectively accumulate at the tumor sites and internalized into the tumor cells by the NIR light illumination and the lowered pHe at the tumor site. These studies demonstrated that PPP-NPs are a promising carrier for future tumor gene delivery.

In Vitro and In Vivo Evaluations of PLGA Microspheres Containing Nalmefene

Poor patient compliance, untoward reactions and unstable blood drug levels after the bolus administration are impeding the pharmacotherapy for insobriety. A long-acting preparation may address these limitations. The aim of this paper was to further investigate the in vitro characteristics and in vivo performances of nalmefene microspheres. Nalmefene was blended with poly (lactide-co-glycolide) (PLGA) to prepare the target microspheres by an O/O emulsification solvent evaporation method. The prepared microspheres exhibited a controlled release profile of nalmefene in vitro over 4 weeks, which was well fitted with a first-order model. In vitro degradation study showed that the drug release in vitro was dominated by both drug diffusion and polymer degradation mechanisms. Pharmacokinetics study indicated that the prepared microspheres could provide a relatively constant of nalmefene plasma concentration for at least one month in rats. The in vivo pharmacokinetics profile was well correlated with the in vitro drug release. Pharmacodynamics studies revealed that the drug loaded microspheres could produce a long-acting antagonism efficacy on rats. These results demonstrated the promising application of injectable PLGA microspheres containing nalmefene for the long-term treatment of alcohol dependence.

Photo-Responsive and NGR-Mediated Multifunctional Nanostructured Lipid Carrier for Tumor-Specific Therapy

A novel nanostructured lipid carrier (NLC) modified with photon-sensitive cell penetrating peptides (psCPP) and Asn-Gly-Arg (NGR) was designed to enhance paclitaxel (PTX)-targeted delivery and antitumor effect. The NGR moiety selectively binds to CD13-positive tumors. On other hand, the psCPP moiety enhance specific cancer cellular uptake after rapidly cleaving the two-photon excitation-responsive protective group, in this case, illumination in the presence of near-IR (NIR) light at the tumor site. The dual-modified NLC (psCPP/NGR-NLC) were prepared by emulsification method, and the concentrations of 1,2-distearoyl-sn-glycero-3-phosphoethanolamine-polyethylene glycol 2000-psCPP (DSPE-PEG2000 -psCPP) and DSPE-PEG5000 -NGR in the NLC were chosen to be 4% and 1% (molar ratio), respectively. The mean particle size of the psCPP/NGR-NLC was about 100 nm, and the drug entrapment efficiency was more than 90%. Stability study showed that the prepared NLCs were physically and chemically stable at 2°C-8°C up to 1 month. Cellular uptake results demonstrated that the proposed psCPP/NGR-NLC had an enhancement of cancer cell recognition and specific uptake. Pharmacokinetic study showed that the prepared psCPP/NGR-NLC possessed the long-circulation characteristic with the t1/2 of 6.112 ± 0.304 h. Pharmacodynamics results confirmed that, with the aid of NIR illumination and NGR, the tumor inhibition ratio of psCPP/NGR-NLC group was significantly higher than the other PTX groups.

Cell-penetrating peptide-siRNA conjugate loaded YSA-modified nanobubbles for ultrasound triggered siRNA delivery.

Due to the absence of effective in vivo delivery systems, the employment of small interference RNA (siRNA) in the clinic has been hindered. In this paper, a new siRNA targeting system for EphA2-positive tumors was developed, based on ultrasound-sensitive nanobubbles (NBs) and cell-permeable peptides (CPPs). Here, a CPP-siRNA conjugate (CPP-siRNA) was entrapped in an ephrin mimetic peptide (YSA peptide)-modified NB (CPP-siRNA/YSA-NB) and the penetration of the CPP-siRNA was temporally masked; local ultrasound stimulation triggered the release of CPP-siRNA from the NBs and activated its penetration. Subsequent research demonstrated that the CPP-siRNA/YSA-NBs had particle sizes of approximately 200 nm and a siRNA entrapment efficiency of more than 85%. The in vitro release results showed that over 90% of the encapsulated CPP-siRNA released from the NBs in the presence of ultrasound, while less than 1.5% of that (30 min) released without ultrasound. Cell experiments showed a the higher CPP-siRNA cellular uptake of CPP-siRNA/YSA-NB among the various formulations in human breast adenocarcinoma cells (MCF-7, EphA2 positive cells). Additionally, after systemic administration in mice, CPP-siRNA/YSA-NB accumulated in the tumor, augmented c-Myc silencing and delayed tumor progression. In conclusion, the application of CPP-siRNA/YSA-NB with ultrasound may provide a strategy for the selective and efficient delivery of siRNA.