Efficacious delivery of protein drugs to prostate cancer cells by PSMA-targeted pH-responsive chimaeric polymersomes
Graphical abstract
Long-circulating and PSMA-targeting pH-sensitive degradable chimaeric polymersomes (Acupa-CPs) efficiently load, deliver and release potent apoptotic proteins like granzyme B to PSMA-overexpressing prostate cancer cells, inducing specific and superior anticancer effects.
Introduction
Protein drugs are one of the most potent biotherapeutics that have shown a tremendous potential in cancer therapy [1], [2], [3]. In compared with chemotherapeutics, protein drugs have advantages of high therapeutic activity, high selectivity, and low toxicity to healthy cells. In the past years, many apoptotic proteins such as TRAIL, herceptin, cytochrome C (CC) and granzyme B (GrB) have been investigated for cancer therapy [4], [5], [6], [7]. The direct administration of protein drugs, however, resulted in typically diminished therapeutic efficacy due to rapid degradation and elimination, poor bioavailability, possible immune response, and low cell permeability. In order to potentiate protein therapy for cancers, different nanosystems ranging from liposomes, nanocapsules, lipid-like nanoparticles, to nanogels have been designed and investigated in vitro and in vivo for intracellular delivery of apoptotic proteins such as antibodies, CC, apoptin, caspase 3, ricin and saporin [8], [9], [10], [11], [12]. Ying et al. recently reported that micellar herceptin nanocomplexes demonstrated longer blood half-life, better tumor selectivity and growth reduction than free herceptin [13]. In particular, polymersomes containing a watery interior are among the most ideal nanocarriers for loading and delivery of therapeutic proteins [14], [15]. It should be noted, nevertheless, that current polymersomes are not optimal as they usually show low protein loading, poor cellular uptake, and/or slow protein release in the target cells.
Enhanced drug and protein release can be achieved via designing stimuli-sensitive polymersomes [16], [17], [18], [19]. In the past years, several stimuli-sensitive polymersome systems that release proteins in response to a signal like acidic pH, glucose or cytoplasmic glutathione have been developed [20], [21], [22], [23]. pH-Sensitive polymersomes are especially appealing because there exists a lower pH in the endosomes and lysosomes of cancer cells (pH 4.0–6.0) as well as in the tumor tissues (pH 6.8–7.2) [24], [25]. We reported previously that acid-degradable polymersomes based on poly(ethylene glycol)-b-poly(2,4,6-trimethoxybenzylidene-pentaerythritol carbonate) (PEG-PTMBPEC) diblock copolymer exhibited accelerated release of chemotherapeutics like doxorubicin hydrochloride (hydrophilic) and paclitaxel (hydrophobic) [26]. However, vesicles have a typically low loading efficacy toward hydrophilic drugs including proteins due to a small volume partition of vesicular core. We found that chimaeric polymersomes (CPs) self-assembled from asymmetric PEG-PCL-PDEA triblock copolymers could efficiently encapsulate various proteins due to active interactions between proteins and PDEA inside of the vesicles [27].
In order to achieve targeted cancer treatment with therapeutic proteins, polymersomes have to be functionalized with cancer homing ligands [28]. In the past years, polymersomes decorated with various ligands like antibody, peptide, or folate have been explored for tumor-targeted chemotherapeutics or siRNA delivery [29], [30], [31], [32], [33]. It should be noted, however, that there are few reports on tumor-targeted polymersomes for controlled delivery of therapeutic proteins. Kokkoli et al. reported that PR_b peptide coupled polymersomes loaded with tumor necrosis factor-alpha showed dramatically enhanced cytotoxicity to LNCaP prostate cancer cells as compared to non-targeting polymersomes [15]. Galactose-decorated reduction-sensitive polymersomes were found to efficiently load and chaperone GrB into hepatocellular carcinoma cells [34].
In this article, we report that 2-[3-[5-amino-1-carboxypentyl]-ureido] pentanedioic acid (Acupa)-decorated pH-responsive chimaeric polymersomes (Acupa-CPs) efficiently deliver therapeutic proteins, CC and GrB, into prostate cancer cells (Scheme 1). Prostate cancer is one of the most common non-cutaneous malignancies in men and is fatal following metastasis. The prostate specific membrane antigen (PSMA) is a clinically validated transmembrane receptor that is over-expressed on the surface of prostate cancer cells as well as in the neovasculature of nearly all non prostate solid tumors [35], [36]. Acupa-installed nanoparticles have proved to actively target to prostate cancer in vitro and in vivo [36], [37], [38]. Notably, Acupa-directed docetaxel-loaded PEG-PLGA nanoparticles have entered Phase II clinical trials for advanced tumor treatments. Here, Acupa-CPs were constructed from poly(ethylene glycol)-b-poly(2,4,6-trimethoxybenzylidene-pentaerythritol carbonate)-b-poly(succinic acid carbonate) (PEG-PTMBPEC-PSAC) and Acupa-PEG-PTMBPEC-PSAC triblock copolymers. The preparation of pH-sensitive degradable Acupa-CPs, loading and pH-triggered release of proteins, PSMA-targeted intracellular protein release, in vitro antitumor activity of protein-loaded Acupa-CPs, as well as in vivo circulation of Acupa-CPs were investigated.
Section snippets
Synthesis of Acupa-PEG-PTMBPEC-PSAC
Acupa-PEG-PTMBPEC-PSAC was synthesized in three steps. Firstly, under a nitrogen atmosphere, to a stirred anhydrous DCM (7.0 mL) solution of NHS-PEG-OH (6.6 kg/mol, 0.33 g, 50 μmol) and TMBPEC (0.75 g, 2.2 mmol) was added a stock solution of zinc bis[bis(trimethylsilyl)amide] in DCM (20 mg/mL, 0.75 mL, 39 μmol). The reaction vessel was sealed and placed in an oil bath thermostated at 40 °C. The polymerization proceeded with magnetic stirring for 4 d. A sample was taken for the determination of monomer
Results and discussion
The clinical translation of polymersomal protein drugs to cancer therapy demands high protein loading, selective recognition and internalization by cancer cells, and fast release of protein inside the cancer cells. It is also equally important that polymersomes are based on biocompatible and degradable polymers and are easy to prepare. To this end, we have designed and developed Acupa-decorated pH-sensitive degradable chimaeric polymersomes (Acupa-CPs) for PSMA-targeted delivery of apoptotic
Conclusions
We have demonstrated that PSMA-targeting pH-sensitive degradable chimaeric polymersomes (Acupa-CPs) could efficiently load, deliver and release apoptotic proteins including cytochrome C and granzyme B to PSMA-overexpressing LNCaP cells, resulting in specific and exceptional anticancer effects. The initial in vivo studies showed that Acupa-CPs had a long circulation time. These multifunctional polymersomes offer several appealing features for targeted protein therapy: (i) they are readily
Acknowledgments
This work is financially supported by research grants from the National Natural Science Foundation of China (NSFC 51273139 and 51473111), the National Science Fund for Distinguished Young Scholars (NSFC 51225302), Ph.D. Programs Foundation of Ministry of Education of China (20133201110005), the Major Program of the Natural Science Foundation of Jiangsu Province (14KJA150008) and a Project Funded by the Priority Academic Program Development (PAPD) of Jiangsu Higher Education Institutions.
References (45)
- et al.
Chitosan-based delivery systems for protein therapeutics and antigens
Adv. Drug Deliv. Rev.
(2010) - et al.
Lapatinib with trastuzumab for HER2-positive early breast cancer (NeoALTTO): a randomised, open-label, multicentre, phase 3 trial
Lancet
(2012) - et al.
TRAIL on trial: preclinical advances in cancer therapy
Trends Mol. Med.
(2013) - et al.
Degradable polymeric nanocapsule for efficient intracellular delivery of a high molecular weight tumor-selective protein complex
Nano Today
(2013) - et al.
The targeted intracellular delivery of cytochrome C protein to tumors using lipid-apolipoprotein nanoparticles
Biomaterials
(2012) - et al.
Near-infrared labeled, ovalbumin loaded polymeric nanoparticles based on a hydrophilic polyester as model vaccine: in vivo tracking and evaluation of antigen-specific CD8 + T cell immune response
Biomaterials
(2015) - et al.
Polymersome carriers: from self-assembly to siRNA and protein therapeutics
Eur. J. Pharm. Biopharm.
(2009) - et al.
Stimuli-responsive nanomaterials for therapeutic protein delivery
J. Control. Release
(2014) - et al.
Reduction and pH dual-bioresponsive crosslinked polymersomes for efficient intracellular delivery of proteins and potent induction of cancer cell apoptosis
Acta Biomater.
(2014) - et al.
Design and development of polymeric micelles with cleavable links for intracellular drug delivery
Prog. Polym. Sci.
(2013)
pH-Sensitive degradable polymersomes for triggered release of anticancer drugs: a comparative study with micelles
J. Control. Release
The highly efficient delivery of exogenous proteins into cells mediated by biodegradable chimaeric polymersomes
Biomaterials
The in vivo behavior and antitumor activity of doxorubicin-loaded poly(gamma-benzyl l-glutamate)-block-hyaluronan polymersomes in Ehrlich ascites tumor-bearing BalB/c mice
Nanomedicine
Polymersomes conjugated with des-octanoyl ghrelin and folate as a BBB-penetrating cancer cell-targeting delivery system
Biomaterials
Functionalized polymersomes with outlayered polyelectrolyte gels for potential tumor-targeted delivery of multimodal therapies and MR imaging
J. Control. Release
Nanomedicine in cancer therapy: challenges, opportunities, and clinical applications
J. Control. Release
Advanced drug and gene delivery systems based on functional biodegradable polycarbonates and copolymers
J. Control. Release
Redox and pH-responsive degradable micelles for dually activated intracellular anticancer drug release
J. Control. Release
Galactose-installed photo-crosslinked pH-sensitive degradable micelles for active targeting chemotherapy of hepatocellular carcinoma in mice
J. Control. Release
Entry and trafficking of granzyme B in target cells during granzyme B-perforin–mediated apoptosis
Blood
Antibody therapeutics in cancer
Science
Drug carriers for the delivery of therapeutic peptides
Biomacromolecules
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