Huijuan Song

An injectable, thermosensitive and multicompartment hydrogel for simultaneous encapsulation and independent release of a drug cocktail as an effective combination therapy platform.

Combination chemotherapy is potent to combat diseases. Simultaneous and segregated delivery of multiple drugs in a single vehicle is essential to achieve this objective. In the present study, an injectable, thermosensitive and multicompartment hydrogel (MCH) was developed by the facile cooperative and incompatible assembly of PEGylated hydrocarbon nanoparticles with PEGylated fluorocarbon nanoparticles. The cooperative assembly behavior was investigated by fluorescence resonance energy transfer (FRET) technology, and the result demonstrated that the incompatible nanoparticle cores possibly accounted for the multicompartment formation in hydrogel. Paclitaxel and doxorubicin could be easily and separately integrated into the different compartments of MCH serving as a sustained drug cocktail formulation. In vitro drug release indicated drugs were liberated in a simultaneous but independent manner without any effect on each other. In vitro and in vivo antitumor activity indicated that peritumoral injection of drug cocktail encapsulated MCH formulation could well achieve the combination effect, which significantly improved the tumor growth inhibition efficiency as well as minimized the drug-associated side effects compared to intravenous injection of free drug cocktail. Furthermore, such a delivery device would allow precise adjustment of drug dosage to the desired effect, achieve spatial-temporal simultaneous and synchronized presence of combination drugs in the target tissue and obviate repeated drug administrations to improve patient compliance. The thermosensitive multicompartment hydrogel cocktail formulation holds great promise for simultaneous and segregated delivery of multiple bioactive agents for sustained combination therapy.

Acid-responsive PEGylated doxorubicin prodrug nanoparticles for neuropilin-1 receptor-mediated targeted drug delivery.

Self-assembled prodrug nanoparticles have demonstrated great promise in cancer chemotherapy. In the present study, we developed a new kind of prodrug nanoparticles for targeted drug delivery. PEGylated doxorubicin conjugate with an acid-cleavable cis-aconityl spacer was prepared. Then it was functionalized with a tumor-penetrating peptide, Cys-Arg-Gly-Asp-Lys (CRGDK), providing the prodrug nanoparticles with the specific binding ability to neurophilin-1 receptor. In acid mediums, doxorubicin could be released from the prodrug nanoparticles with an accumulative release around 60% through the acid-triggered hydrolysis of cis-aconityl bond and nanoparticle disassembly. Whereas, drug release was slow under a neutral pH and the accumulative drug release was less than 16%. In the cell culture tests, our prodrug nanoparticles showed enhanced endocytosis and cytotoxicity in cancer cells including HepG2, MCF-7 and MDA-MB-231 cells, but lower cytotoxicity in human cardiomyocyte H2C9. In the animal experiments, the prodrug nanoparticles were intravenously injected into Balb/c nude mice bearing MDA-MB-231 tumors. Enhanced drug penetration and accumulation in tumors, accompanying with a rapid early tumor-binding behavior, was observed after intravenous injection of the peptide modified prodrug nanoparticles. These data suggests that the acid-sensitive and tumor-targeting PEGylated doxorubicin prodrug nanoparticle may be an efficient drug delivery system for cancer chemotherapy.

Targeted antigen delivery to dendritic cell via functionalized alginate nanoparticles for cancer immunotherapy

Abstract The purpose of the present study was to identify an “easy‐to‐adopt” strategy to enhance immune responses using functionalized alginate (ALG) nanoparticles (MAN‐ALG/ALG=OVA NPs), which were prepared by CaCl2 cross‐linking of two different types of ALG. The mannose (MAN) modified ALG (MAN‐ALG) was used for dendritic cell targeting. The other component, composed of ovalbumin (OVA), a model antigen, is conjugated to ALG (ALG=OVA) via pH sensitive Schiff base bond. Grafting of alginate was demonstrated by FT‐IR and 1H NMR, while the morphological structure, particle size, Zeta potential of MAN‐ALG/ALG=OVA NPs were measured using TEM and DLS. The OVA releasing behavior of MAN‐ALG/ALG=OVA NPs was determined as a function of pH. Antigen uptake was examined by flow cytometry and confocal laser scanning microscopy in vitro using mouse bone marrow dendritic cells (BMDCs). The results showed that MAN‐ALG/ALG=OVA NPs facilitated antigen uptake of BMDCs and cytosolic release of the antigen. Significant up‐regulation of cytokine secretion and expression levels of the surface co‐stimulatory molecules were also observed in MAN‐ALG/ALG=OVA NPs‐treated BMDCs, compared to free OVA. In vivo bio‐distribution study using Cy7 (a near‐infrared fluorescence dye) labeled MAN‐ALG/ALG=OVA NPs showed efficient in vivo trafficking of the nanoparticles from the injection site to the draining lymph nodes. Moreover, MAN‐ALG/ALG=OVA NPs were found to enhance cross‐presentation of OVA to B3Z T cell hybridoma in vitro. Subcutaneous administration of MAN‐ALG/ALG=OVA NPs also induced major cytotoxic T lymphocytes (CTL) response and inhibition of E.G7 tumor growth in C57BL/6 mice. In summary, we report here that the MAN‐ALG/ALG=OVA NPs have the potential as a potent nanovaccine for cancer immunotherapy. Graphical abstract Figure. No Caption available.

Self-assembled PEG–poly(L-valine) hydrogels as promising 3D cell culture scaffolds

Self-assembled polypeptide aggregates have shown great promise in biomedical fields including drug delivery, tissue regeneration and regenerative medicine. In this study, we report self-assembled hydrogels based on mPEG-block-poly(l-valine) (PEV) copolymers. PEV copolymers with varying poly(l-valine) chain lengths were prepared by the ring-opening polymerization of N-carboxy anhydrides of l-valine using mPEG-NH2 as the initiator. 1H NMR and GPC confirmed their well-defined chemical structures. FT-IR analysis and DSC curves indicated the combined α-helix and β-sheet secondary polypeptide conformation and the PEG crystallization microphase in bulk solid state, respectively. Moreover, the poly(l-valine) block restricted the crystallization of PEG segment. DLS, TEM and circular dichroism spectra were employed to study the self-assembly profiles of PEV copolymers in aqueous solution. The results manifested that in diluted solution, PEV copolymers showed a combination of typical β-sheet and α-helical polypeptide structures and self-assembled into nanostructures with diverse morphologies and sizes. For concentrated PEV solutions, clear hydrogel phases were observed and dynamic rheological analyses demonstrated that the hydrogel modulus was sensitive to the polypeptide length, angular frequency, shear strain and temperature. The hydrogel formation was possibly dominated by the physical aggregation of PEV nanoassemblies as well as driven by the formation of particular polypeptide secondary structures. Human fibroblast NIH/3T3 cells were encapsulated and cultured within the hydrogel scaffolds. The encapsulated cells exhibited high viability, suggesting that PEV hydrogels have excellent cytocompatibility and could be used as three-dimensional (3D) cell culture matrices. Collectively, self-assembled PEGylated poly(l-valine) conjugate hydrogels represented a new kind of biomaterial scaffold in biomedical fields including but not limited to 3D cell culture.

Engineering Dendritic-Cell-Based Vaccines and PD-1 Blockade in Self-Assembled Peptide Nanofibrous Hydrogel to Amplify Antitumor T-Cell Immunity

Dendritic cells (DCs) are increasingly used in cancer vaccines due to their ability to regulate T-cell immunity. Major limitations associated with the present DC adoptive transfer immunotherapy are low cell viability and transient duration of transplanted DCs at the vaccination site and the lack of recruitment of host DCs, leading to unsatisfactory T-cell immune response. Here, we developed a novel vaccine nodule comprising a simple physical mixture of the peptide nanofibrous hydrogel, anti-PD-1 antibodies, DCs, and tumor antigens. Upon subcutaneous injection, the vaccine nodule maintained the viability and biological function including the antigen uptake and maturation of encapsulated DCs and simultaneously recruited a number of host DCs and promoted the drainage of activated DCs to lymph nodes, resulting in enhanced proliferation of antigen-specific splenocytes and provoking potent cellular immune responses. Compared with adoptive transfer of DCs and subcutaneous administration of antigen vaccine, such a vaccine nodule shows superior antitumor immunotherapy efficiency in both prophylactic and therapeutic tumor models including delayed tumor growth and prolonged mice survival due to effective stimulation of antitumor T-cell immunity and increased infiltration of activated CD8+ effector T-cells in the tumor. Our findings provide a simple and robust vaccination strategy for DC-based vaccines and also a unique vaccine product for stimulating and enhancing T-cell immunity, holding great promise for immunotherapy against cancer and infectious diseases.

Co-delivery of doxorubicin and pheophorbide A by pluronic F127 micelles for chemo-photodynamic combination therapy of melanoma

Combined chemotherapy and photodynamic therapy (PDT) is a promising strategy to enhance the anticancer efficacy of both drugs via combination effects. In this work, doxorubicin (DOX)-loaded pheophorbide A (PheoA)-modified Pluronic F127 (F127) micelles (DOX/F127-PheoA micelles) were developed for combined chemo-photodynamic therapy of melanoma. DOX/F127-PheoA micelles were characterized in terms of size and size distribution, zeta potential, surface morphology, drug loading efficiency, and drug-releasing properties. It was observed that the DOX/F127-PheoA micelles were spherical, with a mean particle size of 146.5 nm and a zeta potential of -3.2 mV. Confocal laser scanning microscopy showed that DOX/F127-PheoA micelles were internalized by B16 melanoma cells and capable of dual-delivery of both DOX and PheoA into tumor cells. Upon light irradiation, DOX/F127-PheoA micelles could generate reactive oxygen species (ROS) both in vitro and in vivo. The in vitro cytotoxic activity of DOX/F127-PheoA micelles in B16 melanoma cells were evaluated by CCK-8 assay. In vivo antitumor efficacy was also assessed using C57 mice bearing B16 tumors, and the DOX/F127-PheoA micelles were administrated intravenously. Under light irradiation, DOX/F127-PheoA micelles significantly inhibited tumor growth compared with free DOX and DOX/F127-PheoA micelles without light irradiation. The mean tumor growth inhibition rate of DOX/F127-PheoA micelles with light irradiation was 73.5%, compared with 42.3% for DOX/F127-PheoA micelles without light irradiation and 26.5% for free DOX. These results suggest that DOX/F127-PheoA micelles are a versatile and effective drug delivery system for combinational chemo-photodynamic therapy against melanoma.