Nanovaccine Displaying Immunodominant T Cell Epitopes of Fibroblast Activation Protein Is Effective Against Desmoplastic Tumors

Cancer-associated fibroblasts (CAFs), which are dominant cell types in the tumor microenvironment (TME), support tumor growth by secreting cytokines and forming an extracellular matrix (ECM) that hampers the penetration of chemical and biological therapeutics within the tumor and thereby limits their therapeutic efficacy. Here, we report a cancer nanovaccine targeting fibroblast activation protein α (FAP)-expressing CAFs as a potential pan-tumor vaccine. We predicted immunodominant FAP-specific epitope peptides in silico and selected two candidate peptides after in vitro and in vivo screening for immunogenicity and antitumor efficacy. Next, we developed a nanoparticle-based vaccine that displays the two selected epitope peptides on the surface of lipid nanoparticles encapsulating CpG adjuvant (FAPPEP-SLNPs). Immunization with one of two FAPPEP-SLNP nanovaccines led to considerable growth inhibition of various tumors, including desmoplastic tumors, by depleting FAP+ CAFs and thereby reducing ECM production in the TME while causing little appreciable adverse effects. Furthermore, when combined with a chemotherapeutic drug, the FAPPEP-SLNP nanovaccine increased drug accumulation and resulted in a synergistic antitumor efficacy far better than that of each corresponding monotherapy. These findings suggest that our FAPPEP-SLNP nanovaccine has potential for use as an “off-the-shelf” pan-tumor vaccine applicable to a variety of tumors and may be a suitable platform for use in various combination therapies

Facile Immobilization of Biomolecules onto Various Surfaces Using Epoxide-Containing Antibiofouling Polymers

The surface modifications of plastic or glass substrate and the subsequent immobilization of biomolecules onto the surfaces has been a central feature of the fabrication of biochips. To this end, we designed and synthesized new epoxide-containing random copolymers that form stable polymer adlayers on plastic or glass surface and subsequently react with amine or sulfhydryl functional groups of biomolecules under aqueous conditions. Epoxide-containing random copolymers were synthesized by radical polymerization of three functional monomers: a monomer acting as an anchor to the surfaces, a PEG group for preventing nonspecific protein adsorption, and an epoxide group for conjugating to biomolecules. Polymer coating layers were facilely formed on cyclic olefin copolymer (COC) or glass substrate by simply dipping each substrate into a solution of each copolymer. The polymer-coated surfaces characterized by a contact angle analyzer and X-ray photoelectron spectroscopy (XPS) showed very low levels of nonspecific immunoglobulin G (IgG) adsorption compared to the uncoated bare surface (control). Using a microcontact printing (μCP) method, antibodies as representative biomolecules could be selectively attached onto the copolymers-coated glass or COC surface with high signal-to-noise ratios

A Novel Approach to Oral Delivery of Insulin by Conjugating with Low Molecular Weight Chitosan

A new oral delivery system for insulin was developed aiming to improve bioavailability based on a conjugate between insulin and low molecular weight chitosan (LMWC) of narrow molecular weight distribution. The conjugate was synthesized from the reaction between site-specifically modified insulin at the lysine residue of the B-chain and sulfhydryl-modified LMWC. To investigate the effect of MWs of LMWC on oral bioavailability of insulin, various LMWCs (3, 6, 9, and 13k average MW) with narrow MW distribution were used to synthesize LMWC−insulin conjugates. The content of insulin in the LMWC−insulin conjugates was calculated by UV spectrophotometer: 62%, 44%, 38%, and 29% for 3, 6, 9, and 13 kDa LMWC, respectively. The biological activity of insulin in LMWC(6k)−insulin conjugate in vivo was 43 ± 0.7%. LMWC−insulin conjugates after oral administration to diabetic rat models could control blood glucose levels effectively for several hours. Of those conjugates, LMWC(9k)-insulin exhibited the highest pharmacodynamic bioavailability of 3.7 ± 0.3% relative to that of subcutaneously (s.c.) injected insulin (100%)

A Drug-Loaded Aptamer−Gold Nanoparticle Bioconjugate for Combined CT Imaging and Therapy of Prostate Cancer

Computed tomography (CT) is one of the most useful diagnostic tools among commonly used biomedical imaging techniques, which also include magnetic resonance imaging (MRI), positron emission tomography (PET), and ultrasound. However, currently available CT contrast agents, which are based on small iodinated molecules, possess a number of limitations, including a lack of targeted molecular imaging, short imaging time, and renal toxicity. Here, we report a multifunctional nanoparticle for targeted molecular CT imaging and therapy of prostate cancer. By functionalizing the surface of gold nanoparticles (GNPs) with a prostate-specific membrane antigen (PSMA) RNA aptamer that binds to PSMA, we established a targeted molecular CT imaging system capable of specific imaging of prostate cancer cells that express the PSMA protein. The resulting PSMA aptamer-conjugated GNP showed more than 4-fold greater CT intensity for a targeted LNCaP cell than that of a nontargeted PC3 cell. Furthermore, the PSMA aptamer-conjugated GNPs after loading of doxorubicin were significantly more potent against targeted LNCaP cells than against nontargeted PC3 cells

Carbon Nanosyringe Array as a Platform for Intracellular Delivery

We report a novel platform for intracellular delivery of genetic material and nanoparticles, based on vertically aligned carbon nanosyringe arrays (CNSAs) of controllable height. Using this technology, we have shown that plasmid and quantum dots can be efficiently delivered to the cytoplasm of cancer cells and human mesenchymal stem cells. The CNSA platform holds great promise for a myriad of applications including cell-based therapy, imaging, and tracking in vivo, and in biological studies aimed at understanding cellular function

Protein Patterning Based on Electrochemical Activation of Bioinactive Surfaces with Hydroquinone-Caged Biotin

We report a protein attachment and patterning method based on a hydroquinone-caged biotin surface that generates bioactive biotin by mild electrochemical perturbation. The electrochemical activation proceeds under the buffered aqueous environment at neutral pH. It also allows site-selective generation of bioactive biotin for the immobilization of target protein by using prepatterned electrode arrays

Dual Functional, Polymeric Self-Assembled Monolayers as a Facile Platform for Construction of Patterns of Biomolecules

We report a facile approach to the construction of patterns of biomolecules based on polymeric self-assembled monolayers (pSAMs) that possess dual functions:  “bio-reactive (post-functionalizable)” and “bio-inert (anti-biofouling)” properties. To prepare pSAMs on Si/SiO2 wafers were synthesized new random copolymers by radical polymerization of poly(ethylene glycol) methyl ether methacrylate (PEGMA), 3-(trimethoxysilyl)propyl methacrylate (TMSMA), and N-acryloxysuccinimide (NAS), and referred to as poly(TMSMA-r-PEGMA-r-NAS). Poly(TMSMA-r-PEGMA-r-NAS) was designed to play triple roles:  “surface-reactive”, “bio-reactive”, and “bio-inert” ones. The pSAMs of poly(TMSMA-r-PEGMA-r-NAS) were formed on Si/SiO2 wafers with 1 h incubation of the substrates in the polymer solution, which showed approximately a 1 nm-thick film as measured by ellipsometry. After the formation of the pSAMs, the feasibility of the pSAMs as a dual functional surface (bio-inert and bio-reactive properties) was examined. The ability of the pSAMs to block nonspecific adsorption of proteins was evaluated against bovine serum albumin as a model protein. High-resolution N(1s) X-ray photoelectron spectroscopy (XPS) analysis on the protein adsorption revealed that significant reduction up to ∼97% was observed compared to the unmodified Si/SiO2 wafer. In addition, micropatterns of streptavidin with high signal-to-noise ratios were achieved using microcontact printing (μCP) of NH2-bearing biotin onto the pSAMs of poly(TMSMA-r-PEGMA-r-NAS) on glass slides, which suggests that other biomolecules could also be efficiently immobilized onto the pSAMs with high specificity while minimizing nonspecific adsorption. On the other hand, the surface density of both bio-reactive and anti-biofouling functionality could be tailored by simply changing initial feed ratios of each monomer in the polymer synthesis:  different molar ratios of the bio-reactive group (NAS:  33%, 20%, and 10%, respectively) were employed. When micropatterns of streptavidin were constructed, the pSAMs with 33% NAS moiety showed the highest immobilization of the protein. Taken together, the present dual functional, random copolymers may have warrant applications in the field of biosensors and biochips

Bilirubin Nanoparticle-Assisted Delivery of a Small Molecule-Drug Conjugate for Targeted Cancer Therapy

Despite growing interest in targeted cancer therapy with small molecule drug conjugates (SMDCs), the short half-life of these conjugates in blood associated with their small size has limited their efficacy in cancer therapy. In this report, we propose a new approach for improving the antitumor efficacy of SMDCs based on nanoparticle-assisted delivery. Ideally, a nanoparticle-based delivery vehicle would prolong the half-life of an SMDC in blood and then release it in response to stimuli in the tumor microenvironment (TME). In this study, PEGylated bilirubin-based nanoparticles (BRNPs) were chosen as an appropriate delivery carrier because of their ability to release drugs in response to TME-associated reactive oxygen species (ROS) through rapid particle disruption. As a model SMDC, ACUPA-SN38 was synthesized by linking the prostate-specific membrane antigen (PSMA)-targeting ligand, ACUPA, to the chemotherapeutic agent, SN38. ACUPA-SN38 was loaded into BRNPs using a film-formation and rehydration method. The resulting ACUPA-SN38@BRNPs exhibited ROS-mediated particle disruption and rapid release of the SMDC, resulting in greater cytotoxicity toward PSMA-overexpressing prostate cancer cells (LNCaP) than toward ROS-unresponsive ACUPA-SN38@Liposomes. In a pharmacokinetic study, the circulation time of ACUPA-SN38@BRNPs in blood was prolonged by approximately 2-fold compared with that of the SMDC-based micellar nanoparticles. Finally, ACUPA-SN38@BRNPs showed greater antitumor efficacy in a PSMA-overexpressing human prostate xenograft tumor model than SN38@BRNPs or the SMDC alone. Collectively, these findings suggest that BRNPs are a viable delivery carrier option for various cancer-targeting SMDCs that suffer from short circulation half-life and limited therapeutic efficacy

pH-Sensitive Polymer Nanospheres for Use as a Potential Drug Delivery Vehicle

We report the development and characterization of pH-sensitive poly(2-tetrahydropyranyl methacrylate) [poly(THPMA)] nanospheres and demonstrate their feasibility as an effective drug delivery vehicle. Poly(THPMA) nanospheres were prepared using either the double emulsion or single emulsion method for the encapsulation of, respectively, water soluble (rhodamine B) or organic soluble (paclitaxel) payloads. The resulting nanospheres showed pH-dependent dissolution behavior, resulting in significant morphologic changes and loss of nanoparticle mass under mild acidic conditions (pH 5.1) with a half-life of 3.3 days, as compared to physiologic condition (pH 7.4) with a half-life of 6.2 days. The in vitro drug release profile of the paclitaxel-loaded poly(THPMA) nanospheres revealed that the rate of drug release in pH 5.1 acetate buffer was relatively faster than that in pH 7.4 HEPES buffer. Furthermore, poly(THPMA) nanospheres showed lower cytotoxicity and higher cellular uptake as compared to the FDA-approved PLGA-based nanospheres currently in clinical practice