Efficient Doxorubicin Research Articles

Dual-responsive doxorubicin-loaded nanomicelles for enhanced cancer therapy

BackgroundThe enhancement of tumor retention and cellular uptake of drugs are important factors in maximizing anticancer therapy and minimizing side effects of encapsulated drugs. Herein, a delivery nanoplatform, armed with a pH-triggered charge-reversal capability and self-amplifiable reactive oxygen species (ROS)-induced drug release, is constructed by encapsulating doxorubicin (DOX) in pH/ROS-responsive polymeric micelle.ResultsThe surface charge of this system was converted from negative to positive from pH 7.4 to pH 6.8, which facilitated the cellular uptake. In addition, methionine-based system was dissociated in a ROS-rich and acidic intracellular environment, resulting in the release of DOX and α-tocopheryl succinate (TOS). Then, the exposed TOS segments further induced the generation of ROS, leading to self-amplifiable disassembly of the micelles and drug release.ConclusionsWe confirms efficient DOX delivery into cancer cells, upregulation of tumoral ROS level and induction of the apoptotic capability in vitro. The system exhibits outstanding tumor inhibition capability in vivo, indicating that dual stimuli nano-system has great potential to function as an anticancer drug delivery platform.

Targeted doxorubicin-loaded mesenchymal stem cells-derived exosomes as a versatile platform for fighting against colorectal cancer

Exosomes hold great potential for cancer treatment to deliver therapeutics due to its inherent low immunogenicity. Exosomes are biocompatible cell-exocytosed secreted vesicles by most cell types, which can be used to construct novel biomanufacturing platform for drug delivery and cancer therapy. In this study, we implemented nano-sized vesicles which were secreted by mesenchymal stem cell (MSC), to encapsulate doxorubicin (DOX) through electroporation method (DOX@exosome). DOX was loaded into exosomes, with an encapsulation efficiency of up to 35% and separated by ultracentrifugation.Subsequently, carboxylic acid-end MUC1 aptamer was used to covalently decorate the surface amine groups of the exosomes via amide bond formation to provide selective guided drug delivery (DOX@exosome-apt).The data showed that the DOX@exosome-apt provided highly efficient DOX transportation to MUC1-positive cancer cells in vitro as confirmed by MTT and flow cytometry experiments. Moreover, in vivo study on ectopic model of C26 (mouse colon adenocarcinoma) in BALB/c mice indicated that the single dose intravenous injection of DOX@exosome-apt significantly suppress tumor growth in comparison with free DOX. Ex vivo fluorescent imaging also verified the desirable biodistribution of DOX@exosome-apt by exhibiting higher tumor accumulation and faster liver clearance in comparison with DOX@exosome and free DOX. It could be concluded that MUC1 aptamer-decorated exosomes can be implemented therapeutically for the safe and versatile delivery of DOX to colon adenocarcinoma, thus offering valuable platform for clinical applications.

Abstract 1061: Increasing potency of anticancer drugs through Sortilin receptor-mediated cancer therapy: A new targeted approach for the treatment of ovarian cancer

Abstract Rational : The development of personalized therapies against ovarian cancer remains highly challenging even in current modern oncology. One strategy to achieve greater selectivity and better anticancer drug delivery into cancer cells is to conjugate cytotoxic agents to peptide ligands that selectively target receptors abundantly and/or exclusively expressed in these tumor cells. Increased expression of Sortilin (SORT1), a scavenging receptor also known as neurotensin receptor-3, has been observed in invasive ovarian cancer biopsies. In addition, increased SORT1 expression correlated with breast tumor grades. Procedures : In light of these observations, we developed a peptide conjugation platform to target SORT1 and to increase cell selectivity and internalization of anticancer agents. As a proof-of-concept, doxorubicin and docetaxel were conjugated to a Sortilin-binding proprietary peptide (TH19P01). Results : In vitro, significant intracellular delivery of the doxorubicin-TH19P01 conjugate (TH1904) and docetaxel-TH19P01 conjugate (TH1902) were observed in a ES-2 ovarian cancer cell line model while preserving efficient doxorubicin or docetaxel cytotoxic mechanism. TH19P01 and drug conjugate uptake in ovarian cancer cells assays were reduced when SORT1 expression was specifically silenced using siRNA or upon competition with the SORT1 ligands neurotensin and progranulin. Importantly, drug-TH19P01 conjugates were found to bypass the P-glycoprotein (P-gp) efflux pump in MDCK-MDR1 cells overexpressing P-gp as the uptake of conjugates was unaffected by the P-gp inhibitor Cyclosporin A. In vivo, TH1904 and TH1902 caused a more potent inhibition of human ovarian tumor xenografts grown in mice and were better tolerated than their unconjugated parent drugs. Conclusion : These results strongly support future clinical development of this targeted technology platform to generate novel personalized therapeutics with specific indications in Sortilin-positive cancers. Citation Format: Michel Demeule, Jean-Christophe Currie, Cyndia Charfi, Alain Larocque, Alain Zgheib, Sophie Kozelko, Richard Béliveau, Christian Marsolais, Borhane Annabi. Increasing potency of anticancer drugs through Sortilin receptor-mediated cancer therapy: A new targeted approach for the treatment of ovarian cancer [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 1061.

Efficient Doxorubicin Loading to Isolated Dexosomes of Immature JAWSII Cells: Formulated and Characterized as the Bionanomaterial.

Immature dendritic cells (IDc), ‘dexosomes’, are promising natural nanomaterials for cancer diagnose and therapy. Dexosomes were isolated purely from small-scale-up production by using t25-cell-culture flasks. Total RNA was measured as 1.43 ± 0.33 ng/106 cell. Despite the fact that they possessed a surface that is highly abundant in protein, this did not become a significant effect on the DOX loading amount. Ultrasonication was used for doxorubicin (DOX) loading into the IDc dexosomes. In accordance with the literature, three candidate DOX formulations were designed as IC50 values; dExoIII, 1.8 µg/mL, dExoII, 1.2 µg/mL, and dExoI, 0.6 µg/mL, respectively. Formulations were evaluated by MTT test against highly metastatic A549 (CCL-185; ATTC) cell line. Confocal images of unloaded (naïve) were obtained by CellMaskTM membrane staining before DOX loading. Although, dexosome membranes were highly durable subsequent to ultrasonication, it was observed that dexosomes could not be stable above 70 °C during the SEM-image analyses. dExoIII displayed sustained release profile. It was found that dynamic light scattering (DLS) and nanoparticle tracking analysis (NTA) results were in good agreement with each other. Zeta potentials of loaded dexosomes have approximately between −15 to −20 mV; and, their sizes are 150 nm even after ultrasonication. IDcJAWSII dexosomes can be able to be utilized as the “BioNanoMaterial” after DOX loading via ultrasonication technique.

Multi-transformable nanocarrier with tumor extracellular acidity-activated charge reversal, size reduction and ligand reemergence for in vitro efficient doxorubicin loading and delivery.

Various nanoparticles as drug delivery system provide significant improvements in the cancer treatment. However, their clinical success remains elusive in large part due to their inability to overcome both systemic and tumor tissue barriers. The nanosystems with nanoproperty-transformability (surface, size, stability and target) hold great promise for achieving enhanced delivery efficacy. However, currently available systems that are mainly polymer-based assemblies usually suffer from the intrinsic drawbacks of poor stability, premature leakage and low drug loading as well as limited transformability. In this study, we designed a facile strategy to build a novel multi-transformable MSNs@GO nanosystem for efficient doxorubicin (DOX) loading and delivery. This novel nanosystem was well characterized and investigated in vitro. The results indicated that the MSNs@GO can realize a very high drug loading ability due to the large pore surface area of MSNs and the demonstrated donor-acceptor (boron‑nitrogen) coordination interactions between phenylboronic acid-containing nanocarriers and electron donor-containing DOX. More importantly, the novel nanocarriers can simultaneously achieve charge reversal, size reduction and ligand reemergence by shielding/deshielding transition via acid-cleavable dynamic boronate bonds under in vitro simulated acidic microenvironment of tumor tissues, opening a new avenue for improving delivery efficiency of chemotherapeutics.

PH-Controlled Intracellular in Situ Reversible Assembly of a Photothermal Agent for Smart Chemo-Photothermal Synergetic Therapy and ATP Imaging.

To advance anti-tumor efficiency and lessen the adverse effect caused by nanodrug residues in the body, a smart nanoagent system is developed and successfully used in intracellular ATP imaging and in vivo chemo-photothermal synergetic therapy. The nanoagent system is facilely prepared using a DNA complex to modify gold nanoparticles (AuNPs). The DNA complex is formed by three oligonucleotides (ATP aptamer, rC-DNA, and rG-DNA). The CG-rich structure in a ternary DNA complex could be exploited for payload of chemotherapeutic medicine doxorubicin (DOX), thus making efficient DOX transport into the tumor site possible. In tumor cells, especially in acidic organelles (e.g., endosome and lysosome), DOX could be rapidly released via the dual stimuli of overexpressed ATP and pH. What is more, the specific recognition of a fluorescently labeled aptamer strand to ATP can achieve the intracellular ATP imaging. pH-controlled reversible folding and unfolding of intermolecular i-motif formed by C-rich strands can lead to intracellular in situ assembly of AuNP aggregates with high photothermal conversion efficiency and promote relatively facile renal clearance of AuNPs through the disassociation of the aggregates in extracellular environments. Experiments in vivo and vitro present feasibility for a synergetic chemo-photothermal therapy. Such an in situ reversible assembly strategy of a chemo-photothermal agent also presents a new paradigm for a smart and highly efficient disease treatment with reduced side effects.

Engineered borate ester conjugated protein-polymer nanoconjugates for pH-responsive drug delivery.

To improve the clinical efficiency of cytotoxic anticancer drugs e.g. doxorubicin (DOX), reduce the severe off-target side effects, and allow the more biocompatible and biodegradable drug penetration into tumor cells, our research efforts developed a new DOX-conjugated protein polymer nanoconjugates (PPNCs) prodrugs delivery system. Briefly, DOX was conjugated to bovine serum albumin (BSA) and the complex was treated with lactobionic acid (LA) as well as folic acid (FA) to enhance drug endocytosis and targeting selectivity. Such functionalized BSA could be conjugated with a designed phenylboronic acid functionalized poly(N-isopropylacrylamide) (PNIPAAm) via forming a pH-sensitive borate ester bond to give the functionalized PPNCs prodrugs. The potential of the PPNCs prodrugs on tumor cells therapy was systematically evaluated in dose/time-dependent effects. In vitro results showed a rapid accumulation of the prodrugs into the MDA-MB-231 tumor cell during the first 30 min and reached maximum at 24 h. Moreover, the cell-killing effect was observed quickly after 4 h incubation with an IC50 of 0.5 mg/mL (≈4 μM/L). In general, given the efficient pH-dependent DOX release of these constructed nanoconjugates, it is anticipated to contribute a potential delivery strategy for cancer therapy.

H2O2-responsive polymeric micelles with a benzil moiety for efficient DOX delivery and AIE imaging.

Nano drug delivery is a promising domain in biomedical theranostics and has aroused more and more attention in recent years. We report here an amphiphilic polymer TPG1, bearing a H2O2-sensitive benzil and an AIE fluorophore tetraphenylethene (TPE) unit, which is able to self-assemble into spherical nanosized micelles in aqueous solution. Doxorubicin (DOX) can be encapsulated into TPG1 micelles efficiently with the loading capability of up to 59% by weight. The benzil moiety could be cleaved via the Baeyer-Villiger type reaction in the presence of H2O2, leading to the decomposition of TPG1 micelles and release of DOX. In vitro studies indicated that DOX-loaded TPG1 micelles can be internalized by cancer cells, followed by unloading encapsulated DOX under the stimulation of H2O2. The drug release process can be monitored by the AIE fluorescence from the degradation products containing a TPE moiety. MTT assays against HeLa and HepG2 cancer cells demonstrated that DOX-loaded micelles showed good anticancer efficacy. The polymer TPG1 and the corresponding decomposed products showed great biocompatibility. Our data suggest that TPG1 has the potential to be employed for the controlled drug delivery system.

Gelatin-poly (ethylene glycol) methyl ether-functionalized porous Nanosilica for efficient doxorubicin delivery

Porous nanosilica (PNS) has been receiving wider attention in the fabrication of nanocarriers for drug delivery. However, unmodified PNS nanoparticles have shown an initial rapid release of encapsulated drugs, which may limit their potential applications in the clinical setting. In this report, in order to improve the efficiency of drug delivery, PNS nanoparticles were first synthesized and then surface conjugated with gelatin-poly (ethylene glycol) methyl ether (GEL-mPEG) to form PNS-GEL-mPEG nanocarriers for doxorubicin (DOX) delivery. The co-polymer structure and morphology of the obtained nanocarriers were analyzed using Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), thermogravimetric analysis (TGA), transmission electron microscopy (TEM) and dynamic light scattering (DLS). The loading capacity, encapsulation efficiency and DOX release behavior of DOX@PNS-GEL-mPEG nanocarriers were also evaluated. Results showed that the conjugated PNS nanocarriers were spherical shape with an average diameter of 69.60 ± 3.27 nm, as compared to 58.93 ± 2.42 nm of PNS nanocarriers. Also, the PNS-GEL-mPEG nanoparticles showed their ability to effectively encapsulate DOX. In detail, DOX was significantly encapsulated into PNS-GEL-mPEG nanocarriers to form DOX@PNS-GEL-mPEG nanocarriers with high loading efficiency of 85.88 ± 0.15%. Moreover, the synthesized DOX@PNS-GEL-mPEG nanoparticles exhibited a sustainable release of DOX up to 96 h, without a burst release, as compared with less than 2 h from unconjugated PNS nanocarriers, and exhibited a pH-dependent drug release behavior of DOX in acidic media. These results indicated that DOX@PNS-GEL-mPEG nanocarriers have high potential applications for efficient DOX loading and release in cancer therapy.

Development of doxorubicin hydrochloride loaded pH-sensitive liposomes: Investigation on the impact of chemical nature of lipids and liposome composition on pH-sensitivity

This study investigates the impact of the chemical nature of lipids and additive on the formulation and properties of pH sensitive liposomes. The objective is to understand the respective role of the formulation parameters on the liposome properties in order to optimize the conditions for efficient encapsulation of doxorubicin (DOX). These liposomes should be stable at physiological pH, and disrupt in slightly acidic media such as the tumor microenvironment to release their DOX load. The major challenge for encapsulating DOX in pH sensitive liposomes lies in the fact that this drug is soluble at low pH (when the pH-sensitive liposomes are not stable), but the DOX aqueous solubility decreases in the pH conditions corresponding to the stability of the pH-sensitive liposomes. The study of pH-sensitivity of liposomes was conducted using carboxyfluorescein (CF) encapsulated in high concentration, i.e. quenched, and following the dye dequenching as sensor of the liposome integrity. We studied the impact of (i) the chemical nature of lipids (dioleoyl phosphatidyl ethanolamine (DOPE), palmitoyl-oleoyl phosphatidyl ethanolamine (POPE) and dimyristoyl phosphatidyl ethanolamine (DMPE)) and (ii) the lipid/stabilizing agent ratio (alpha-tocopheryl succinate), on the pH sensitivity of the liposomes. Optimized liposome formulations were then selected for the encapsulation of DOX by an active loading procedure, i.e. driven by a difference in pH inside and outside the liposomes. Numerous experimental conditions were explored, in function of the pH gradient and liposome composition, which allowed identifying critical parameters for the efficient DOX encapsulation in pH-sensitive liposomes.

GQDs-MSNs nanocomposite nanoparticles for simultaneous intracellular drug delivery and fluorescent imaging

Although number of stimuli-responsive drug delivery systems based on mesoporous silica nanoparticles (MSNs) have been developed, the simultaneous real-time monitoring of carrier in order to guarantee proper drug targeting still remains as a challenge. GQDs-MSNs nanocomposite nanoparticles composed of graphene quantum dots (GQDs) and MSNs are proposed as efficient doxorubicin delivery and fluorescent imaging agent, allowing to monitor intracellular localization of a carrier and drug diffusion route from the carrier.Graphene quantum dots (average diameter 3.65 ± 0.81 nm) as a fluorescent agent were chemically immobilized onto mesoporous silica nanoparticles (average diameter 44.08 ± 7.18 nm) and loaded with doxorubicin. The structure, morphology, chemical composition, and optical properties as well as drug release behavior of doxorubicin (DOX)-loaded GQDs-MSNs were investigated. Then, the in vitro cytotoxicity, cellular uptake, and intracellular localization studies were carried out. Prepared GQDs-MSNs form stable suspensions exhibiting excitation-dependent photoluminescence (PL) behavior. These nanocomposite nanoparticles can be easily DOX-loaded and show pH- and temperature-dependent release behavior. Cytotoxicity studies proved that GQDs-MSNs nanocomposite nanoparticles are nontoxic; however, when loaded with drug, they enable the therapeutic activity of DOX via its active delivery and release. GQDs-MSNs owing to their fluorescent properties and efficient in vitro cellular internalization via caveolae/lipid raft-dependent endocytosis show a high potential for the optical imaging, including the simultaneous real-time optical tracking of the loaded drug during its delivery and release.Graphical abstractᅟ

Sialic-Acid-Anchored Micelles: A Hierarchical Targeting Device for Enhanced Tumor Tissue Accumulation and Cellular Internalization.

Targeted drug delivery systems (TDDS) have attracted wide attention for their reduced drug side effects and improved antitumor efficacy in comparison with traditional preparations. While targeting moieties in existing TDDS have principally focused on recognition of receptors on the surface of tumor cells, accumulation into tumor tissue only could be performed by enhanced permeability and retention effects and active transportation into tumor cells. Doxorubicin (DOX)-loaded sialic acid-dextran (Dex)-octadecanoic acid (OA) micelles (SA-Dex-OA/DOX) were designed for targeting hepatocellular carcinoma effectively. The synthesized conjugates could self-aggregate to form micelles with a critical micelle concentration of 27.6 μg·mL-1 and diameter of 54.53 ± 3.23 nm. SA-Dex-OA micelles incorporated with 4.36% DOX-loading content could prolong in vitro drug release to 96 h with 80% of final release. Cellular transportation studies revealed that SA-Dex-OA micelles mediated more efficient DOX delivery into Bel-7402 cells than those without SA modification. In vivo biodistribution testing demonstrated that SA-Dex-OA/ICG micelles showed 3.05-fold higher accumulation into Bel-7402 tumors. The recognition of overexpressed E-selectin in inflammatory tumor vascular endothelial cells led to a large accumulation of SA-Dex-OA/ICG micelles into tumor tissue, and the E-selectin upregulated on the surface of tumor cells contributed to active cellular transportation into tumor cells. Accordingly, SA-Dex-OA/DOX exhibited prior suppression of Bel-7402 tumor growth greater than that of Dex-OA/DOX micelles and free DOX (the tumor inhibition: 79.2% vs 61.0 and 51.3%). These results suggest that SA-functionalized micelles with dual targeting properties have high potential for liver cancer therapy.

Tumor Microenvironment‐Responsive Mesoporous MnO2‐Coated Upconversion Nanoplatform for Self‐Enhanced Tumor Theranostics

AbstractThe insufficient blood flow and oxygen supply in solid tumor cause hypoxia, which leads to low sensitivity of tumorous cells and thus causing poor treatment outcome. Here, mesoporous manganese dioxide (mMnO2) with ultrasensitive biodegradability in a tumor microenvironment (TME) is grown on upconversion photodynamic nanoparticles for not only TME‐enhanced bioimaging and drug release, but also for relieving tumor hypoxia, thereby markedly improving photodynamic therapy (PDT). In this nanoplatform, mesoporous silica coated upconversion nanoparticles (UCNPs@mSiO2) with covalently loaded chlorin e6 are obtained as near‐infrared light mediated PDT agents, and then a mMnO2 shell is grown via a facile ultrasonic way. Because of its unique mesoporous structure, the obtained nanoplatform postmodified with polyethylene glycol can load the chemotherapeutic drug of doxorubicin (DOX). When used for antitumor application, the mMnO2 degrades rapidly within the TME, releasing Mn2+ ions, which couple with trimodal (upconversion luminescence, computed tomography (CT), and magnetic resonance imaging) imaging of UCNPs to perform a self‐enhanced imaging. Significantly, the degradation of mMnO2 shell brings an efficient DOX release, and relieve tumor hypoxia by simultaneously inducing decomposition of tumor endogenous H2O2 and reduction of glutathione, thus achieving a highly potent chemo‐photodynamic therapy.

A Novel AS1411 Aptamer-Based Three-Way Junction Pocket DNA Nanostructure Loaded with Doxorubicin for Targeting Cancer Cells in Vitro and in Vivo.

Active targeting of nanostructures containing chemotherapeutic agents can improve cancer treatment. Here, a three-way junction pocket DNA nanostructure was developed for efficient doxorubicin (Dox) delivery into cancer cells. The three-way junction pocket DNA nanostructure is composed of three strands of AS1411 aptamer as both a therapeutic aptamer and nucleolin target, the potential biomarker of prostate (PC-3 cells) and breast (4T1 cells) cancers. The properties of the Dox-loaded three-way junction pocket DNA nanostructure were characterized and verified to have several advantages, including high serum stability and a pH-responsive property. Cellular uptake studies showed that the Dox-loaded DNA nanostructure was preferably internalized into target cancer cells (PC-3 and 4T1 cells). MTT cell viability assay demonstrated that the Dox-loaded DNA nanostructure had significantly higher cytotoxicity for PC-3 and 4T1 cells compared to that of nontarget cells (CHO cells, Chinese hamster ovary cell). The in vivo antitumor effect showed that the Dox-loaded DNA nanostructure was more effective in prohibition of the tumor growth compared to free Dox. These findings showed that the Dox-loaded three-way junction pocket DNA nanostructure could significantly reduce the cytotoxic effects of Dox against nontarget cells.

Development and Evaluation of Tri-Functional Immunoliposomes for the Treatment of HER2 Positive Breast Cancer.

Trastuzumab combined with Doxorubicin (DOX) demonstrates significant clinical activity in human epidermal growth factor receptor-2 (HER2)-positive breast cancer (BC). However, emergence of treatment resistance and trastuzumab associated cardiotoxicity remain clinical challenges. In an effort to improve patient outcome, we have developed and evaluated novel tri-functional immunoliposomes (TFIL) that target HER2-receptors on BC cells and CD3-receptors on T-lymphocytes, and deliver DOX. Trastuzumab (anti-HER2) and OKT-3 (anti-CD3) antibodies were conjugated to liposomes using a micelle-transfer method. Cytotoxicity of targeted immunoliposomes loaded with DOX was examined in vitro on HER2-positive BC cells (BT474), with peripheral blood monocytic cells (PBMC) as immune effector cells. TFIL demonstrated high antibody-liposome conjugation ratios (100-130μg protein/μmol phospholipid) and cargo capacity (0.21mol:mol drug:lipid), highly efficient DOX loading (>90%), a particle size favorable for extended circulation (~150nm), and good stability (up to 3months at 4°C). In the presence of PBMCs, TFIL showed complete killing of BT474 cells, and were superior to mono-targeted trastuzumab-bearing liposomes, non-targeted liposomes, and free Trastuzumab and DOX. Novel anti-HER2xCD3 + DOX TFIL show promise as a means to both engage immune cells against HER2 positive breast cancer cells and deliver chemotherapy, and have the potential to improve clinical outcomes.

PH-sensitive doxorubicin-conjugated prodrug micelles with charge-conversion for cancer therapy

Intelligent drug delivery systems with prolonged circulation time, reduced drug leakage in blood, target site-triggered drug release and endosomal escape are attractive and ideal for malignant tumor therapy. Herein, doxorubicin (DOX)-conjugated smart polymeric micelles based on 4-carboxy benzaldehyde-grafted poly (L-lysine)-block-poly (methacryloyloxyethyl phosphorylcholine) (PLL(CB/DOX)-b-PMPC) copolymer are prepared. DOX and electronegative 4-carboxy benzaldehyde are conjugated to the PLL block via an imine linkage and as a result, the drug loaded micelles exhibited the pH-triggered charge-conversion property and accelerated drug release at tumor pH. In vitro cytotoxicity studies of these DOX-loaded micelles exhibited great tumor inhibition against HeLa and 4T1 cells. Moreover, in mice models of breast cancer, these DOX-loaded micelles showed better anti-tumor efficacy and less organ toxicity than free drug. In summary, these polymeric micelles could be applied as potential nanocarriers for cancer therapy. Statement of SignificanceAs a typical anti-cancer drug, Doxorubicin (DOX) exhibited remarkable tumor inhibition but was limited by its low drug utilization and strong toxicity to organs. To overcome these challenges, we developed a DOX-conjugated polymeric micelle as a nano drug carrier which was endowed with pH-sensitivity and charge-conversion function. The structure of micelles would quickly disintegrate with surface charge-conversion in acidic environment, which would contribute to the endosomal escape and accelerated drug release. These DOX-conjugated micelles would provide a promising platform for the efficient DOX delivery and better anti-cancer efficiency.

Protease-activatable cell-penetrating peptide possessing ROS-triggered phase transition for enhanced cancer therapy

Reactive oxygen species (ROS)- or protease-responsive materials have been utilized as carriers in cancer therapies because ROS and specific proteases are overproduced in cancer cells. Methionine-based polypeptides containing a thioether group are promising candidates due to their ROS-responsiveness which provides a phase transition. Herein, we developed protease-activatable cell-penetrating peptide containing a ROS-responsive methionine, a cell permeable lysine chain, and a matrix metalloproteinase (MMP)-cleavable linker. We designed a poly(l-methionine-block-l-lysine)-PLGLAG-PEG (MLMP) and doxorubicin (DOX) was loaded into the micelle core. The MLMP exhibited MMP-sensitive cleavage and ROS-induced DOX release. Moreover, we confirmed efficient DOX delivery into cancer cells and induction of the apoptotic capability in vitro. In a bio-distribution study, IR-780 dye encapsulated MLMP showed superior tumor targetability with long retention. Furthermore, MLMP (DOX) exhibited outstanding tumor inhibition capability with non-toxicity compared to free DOX, indicating that dual stimuli-MLMP has great potential as an anticancer drug delivery platform.

PH-responsive poly(ethylene glycol)-poly(ϵ-caprolactone)-poly(glutamic acid) polymersome as an efficient doxorubicin carrier for cancer therapy

The synthesis, characterization and potential application in doxorubicin (Dox) delivery system of an biodegradable polypeptide-based block copolymer: poly(ethylene glycol)2000-poly(e-caprolactone)6000-poly(glutamic acid)1000 (PEG2000-PCL6000-PGA1000) were investigated. The copolymer was synthesized via ring-opening polymerization (ROP) and characterized by 1H-NMR and FTIR. The synthesized copolymer could self-assemble into aggregates and the critical aggregation concentration was 0.23 mg/mL. Transmission electron microscope (TEM) indicated that the spherical polymersomes formed with a desirable size about 180 nm. Therefore Dox was encapsulated into these polymersomes, and then investigated its applications in drug delivery system. This Dox-loaded polymersomes (PolyDox) were characterized by dynamic light scattering (DLS), zeta potential and pH responsiveness measurements. In vitro drug release indicated the release rate of drug from PolyDox was pH-responsive and significantly decreased. The drug pharmacokinetic parameters were improved in comparsion to the group treated with free Dox, which proved the prolonged Dox release from PolyDox. WST-1 assay indicated a low toxicity and good compatibility of copolymer to cells within 48 h. The results also showed PolyDox appeared to induce higher antitumor effect. Cell uptake results indicated that PolyDox displayed higher cellular uptaken in A549 cells. Endocytosis inhibition results demonstrated the internalization of PolyDox was mostly mediated by fluid-phase endocytosis pathway.

Abstract 5146: Increasing penetration of anticancer drugs through sortilin receptor-mediated cancer therapy: A new targeted and personalized Approach in the treatment of ovarian cancer

Abstract The development of personalized therapies against ovarian cancer remains highly challenging in current modern oncology. One way to achieve greater selectivity and better anticancer drug delivery into cancer cells is to conjugate cytotoxic agents to specific peptide ligands that will selectively target receptors abundantly and/or exclusively expressed on these cells. Increased expression of Sortilin, a scavenging receptor, has been clinically observed in several human cancers including breast, prostate, colon, pancreas, skin, and pituitary. In particular, Sortilin has also been reported to be overexpressed in ovarian cancers as compared to non-malignant ovarian tissue. In light of this, we developed a peptide conjugation platform using a new Sortilin receptor-mediated vectorization strategy to increase cell targeting selectivity and cell delivery efficacy of anticancer agents. As a proof-of-concept, Doxorubicin was conjugated to peptide sequences, termed Katana peptides (KA). In vitro, significantly increased Sortilin mediated intracellular delivery of the Doxorubicin-Katana peptide conjugate (DoxKA) was observed in SKOV3 and ES-2 ovarian cancer cell line models, with conserved efficient Doxorubicin cytotoxic mechanism. Uptake of DoxKA in ES-2 ovarian cancer cells was reduced when Sortilin expression was specifically silenced by using siRNA or upon competition with the Sortilin ligands neurotensin and progranulin. In addition, DoxKA was found to bypass the P-glycoprotein (P-gp) efflux pump since, in contrast to Doxorubicin uptake in MDCK-MDR1 cells overexpressing the P-gp efflux pump, the uptake of DoxKA was unaffected by the P-gp inhibitor Cyclosporin A. In vivo, DoxKA was better tolerated and caused a more potent inhibition of human ovarian tumor xenografts growth than did Doxorubicin alone. These results provide strong evidence for the potential of this drug development platform in the generation of novel personalized therapeutics with specific targeting of SORT1-positive cancer cells. Citation Format: Michel Demeule, Jean-Christophe Curie, Alain Larocque, Cyndia Charfi, Richard Béliveau, Claude Vezeau, Borhane Annabi. Increasing penetration of anticancer drugs through sortilin receptor-mediated cancer therapy: A new targeted and personalized Approach in the treatment of ovarian cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 5146. doi:10.1158/1538-7445.AM2017-5146

Riboflavin-containing telodendrimer nanocarriers for efficient doxorubicin delivery: High loading capacity, increased stability, and improved anticancer efficacy.

We have developed two linear-dendritic telodendrimers (TDs) with rational design using amphiphilic riboflavin (Rf) as building blocks for efficient doxorubicin (DOX) delivery. Micellar TD nanoparticles (NPs) are composed of a hydrophilic polyethylene glycol (PEG) shell and a Rf-containing affinitive core for DOX encapsulation. Strong DOX-Rf interactions and amphiphilic Rf structure render these nanocarriers with an ultra-high DOX loading capacity (>1/1, DOX/TD, w/w), ∼100% loading efficiency, the sustained drug release and the optimal particle sizes (20-40nm) for efficient tumor-targeted drug delivery. These nanoformulations significantly prolonged DOX circulation time in the blood without the accelerated clearance observed after multiple injections. DOX-TDs target several types of tumors efficiently invivo, e.g. Raji lymphoma, MDA-MB-231 breast cancer, and SKOV-3 ovarian cancer. Invivo maximum tolerated dose (MTD) of DOX was increased by 2-2.5 folds for the nanoformulations in mice relative to those of free DOX and Doxil®. These nanoformulations significantly inhibited tumor growth and prolonged survival of mice bearing SKOV-3 ovarian cancer xenografts. In summary, Rf-containing nanoformulations with high DOX loading capacity, improved stability and efficient tumor targeting lead to superior antitumor efficacy, which merit the further development for clinical application.