Infrared Responsive Choline Phosphate Lipids for Synergistic Cancer Therapy

Choline phosphate lipids have been designed and developed as new-generation zwitterionic nanocarriers with excellent biocompatibility and bioorthogonality to provide a more programmable performance for cancer therapy. However, there is a lack of spatiotemporal and reversible control for drug release at target tumor cells, which can lead to severe adverse effects to normal tissue and discounted treatment outcome. Here, light-inducible Lip-cRGDfk/ICG/Dox liposomes were developed for synergistic cancer therapy. ICG can effectively convert light energy into selective heating in a local environment upon laser irradiation, thus inducing thermal ablation of tumor cells, and further reversibly trigger the spatiotemporal release of anticancer drugs (Dox) at tumor cells due to the conformation transformation of CP lipids to synergistically kill tumor cells. That Lip-cRGDfk/ICG/Dox exhibited a significant improvement for breast cancer therapy in vitro and in vivo is also demonstrated, thus it can serve as an efficient platform to noninvasively and spatiotemporally control the activation of cytotoxicity at tumor cells for precision cancer therapy.     

A microRNA-21-responsive doxorubicin-releasing sticky-flare for synergistic anticancer with silencing of microRNA and chemotherapy

A sticky-flare gold nanoparticle probe(AuNP-probe) is designed by the combination of locked nucleic acid functionalized silencing of microRNA technology for intracellular microRNA-21(miRNA-21) sensitively detecting, fluorescence imaging,localizing and silencing. The limit of detection is as low as 0.01 n M. Overexpressed miRNA-21 in cancer cells serves as endogenous drug release stimuli to trigger the release of probe-loaded doxorubicin(Dox), which soon translocates into cell nuclei. This multifunctional Dox-loaded AuNP-probe(Dox-AuNP-probe) could induce cancer cell apoptosis effectively through the synergistic effect of gene silencing and chemotherapy. This Dox-AuNP-probe exhibits superior drug potency compared to free Dox molecules, with a cell inhibition rate of 57%(but only 20% for Dox) to wild-type cancer cells and 30%(but 0% for Dox) to drug-resistent cancer cells after 72 h, and this strategy not only has the function of sensing, but also can effectively bypass drug resistance. In MCF-7 xenograft tumor-bearing mice, the Dox-AuNP-probes show greater inhibition for tumor tissues than miRNA-21 targeted AuNP-probes(Targeting-AuNP-probe) or free Dox molecules. Therefore, the Dox-AuNP-probe represents a promising nanotheranostic platform for future applications in cancer molecular imaging and therapy, especially providing a potential strategy to treat resistant cancers.     

Enzyme‐Responsive Multifunctional Magnetic Nanoparticles for Tumor Intracellular Drug Delivery and Imaging

Enzyme‐responsive, hybrid, magnetic silica nanoparticles have been employed for multifunctional applications in selective drug delivery and intracellular tumor imaging. In this study, doxorubicin (Dox)‐conjugated, enzyme‐cleavable peptide precursors were covalently tethered onto the surface of uniform silica‐coated magnetic nanoparticles through click chemistry. This enzyme‐responsive nanoparticle conjugate demonstrated highly efficient Dox release upon specific enzyme interactions in vitro. It also exhibits multiple functions in selective tumor intracellular drug delivery and imaging in the tumor cells with high cathepsin B expression, whereas it exhibited lower cytotoxicity towards other cells without enzyme expression.     

Reversal of Multidrug Resistance by Apolipoprotein A1-Modified Doxorubicin Liposome for Breast Cancer Treatment

Multidrug resistance (MDR) remains a major problem in cancer therapy and is characterized by the overexpression of p-glycoprotein (P-gp) efflux pump, upregulation of anti-apoptotic proteins or downregulation of pro-apoptotic proteins. In this study, an Apolipoprotein A1 (ApoA1)-modified cationic liposome containing a synthetic cationic lipid and cholesterol was developed for the delivery of a small-molecule chemotherapeutic drug, doxorubicin (Dox) to treat MDR tumor. The liposome-modified by ApoA1 was found to promote drug uptake and elicit better therapeutic effects than free Dox and liposome in MCF-7/ADR cells. Further, loading Dox into the present ApoA1-liposome systems enabled a burst release at the tumor location, resulting in enhanced anti-tumor effects and reduced off-target effects. More importantly, ApoA1-lip/Dox caused fewer adverse effects on cardiac function and other organs in 4T1 subcutaneous xenograft models. These features indicate that the designed liposomes represent a promising strategy for the reversal of MDR in cancer treatment.     

Targeted Tumor Therapy Based on Nanodiamonds Decorated with Doxorubicin and Folic Acid

The fabrication of nanodiamond (ND)‐based drug carriers for tumor‐targeted drug delivery is described. The ND clusters with an average size of 52.84 nm are fabricated using a simple fluidic device combined with a precipitation method and then conjugated with folic acid (FA) and doxorubicin (Dox) via carbodiimide chemistry to obtain FA/Dox‐modified ND (FA/Dox‐ND) clusters. Cell culture experiments revealed that KB (folate receptor‐positive) cells are preferentially ablated by FA/Dox‐ND clusters compared to A549 (folate receptor‐negative) cells. In vivo results revealed that FA/Dox‐ND clusters are specifically accumulated in tumor tissues after intravenous injection into tumor‐bearing mice, effectively reducing the volume of tumor. Based on these results, this study suggests that FA/Dox‐ND clusters can be a good candidate as tumor‐targeted nanovehicles for delivery of antitumor drug.

     

Polyphosphazene nanoparticles for cytoplasmic release of doxorubicin with improved cytotoxicity against Dox-resistant tumor cells

This study involved the construction of self-assembled nanoparticles from novel pH-sensitive amphiphilic polyphosphazenes. These nanoparticles provide fast pH-responsive drug release and have the capability to disturb endosomal membranes. The polymers were prepared by linking N,N-diisopropylethylenediamine (DPA) onto a backbone of PEGylated polyphosphazene. In vitro cell viability measurements demonstrated the superior efficacy of these pH-responsive nanoparticles over free doxorubicin (Dox): the IC50 was over 60 times lower than that of free Dox against a Dox-resistant cell line. Using flow cytometry and confocal microscopy, the further investigation of the intracellular distribution of Dox and fluorescent probes provided evidence that, upon internalization by cells through endocytic pathways, the pH-sensitive polymer would disrupt membranes of endosomal compartments, releasing the cargo drugs into the cytoplasm in a burst-like manner. This resulted in reduced likelihood of drug efflux via exocytosis, and reversal of the drug resistance of the tumor cells. Generally, the pH-responsive nanoparticles designed in this study have achieved their potential as a drug delivery system for tumor therapy applications.     

Chemophototherapeutic Ablation of Doxorubicin-Resistant Human Ovarian Tumor Cells†

Porphyrin-phospholipid (PoP) liposomes loaded with Doxorubicin (Dox) have been demonstrated to be an efficient vehicle for chemophototherapy (CPT). Multidrug resistance (MDR) of cancer cells is a problematic phenomenon in which tumor cells develop resistance to chemotherapy. Herein, we report that Dox-resistant tumor cells can be ablated using our previously described formulation termed long-circulating Dox loaded in PoP liposomes (LC-Dox-PoP), which is a PEGylated formulation containing 2 mol. % of the PoP photosensitizer. In vitro studies using free Dox and LC-Dox-PoP showed that human ovarian carcinoma A2780 cells were more susceptible to Dox compared to the corresponding Dox-resistant A2780-R cells. When CPT was applied with LC-Dox-PoP liposomes, effective killing of both nonresistant and resistant A2780 cell lines was observed. An in vivo study to assess the efficiency of LC-Dox-PoP showed effective tumor shrinkage and prolonged survival of athymic nude mice bearing subcutaneous Dox-resistant A2780-R tumor xenografts when they were irradiated with a red laser. Biodistribution analysis demonstrated enhanced tumoral drug uptake in Dox-resistant tumors with CPT, suggesting that increased drug delivery was sufficient to induce ablation of resistant tumor cells.     

Synthesis of HPMA Copolymers Containing Doxorubicin Bound via a Hydrazone Linkage. Effect of Spacer on Drug Release and in vitro Cytotoxicity

The aim of this study was the synthesis, physico‐chemical characterization and preliminary evaluation of biological activity of novel polymer drugs based on conjugates of anti‐cancer drug doxorubicin (Dox) with water‐soluble polymer drug carriers based on N‐(2‐hydroxypropyl)methacrylamide (HPMA) copolymers. In the conjugates, Dox is attached to the polymer via a pH‐sensitive linkage susceptible to hydrolysis at pH ≈ 5–6, thus enabling intracellular Dox release. Seven Dox‐containing polymer conjugates differing in the length and structure of the single‐amino‐acid or oligopeptide spacer were synthesized (Gly, β‐Ala, 6‐aminohexanoyl, 4‐aminobenzoyl, GlyGly, GlyLeuGly, Gly‐DL ‐PheLeuGly) and the relationship between the spacer structure and the rate of in vitro Dox release was studied at various pH. The rate of Dox release at pH 5 (close to lysosomal pH) ranged from 70 to 96% of total Dox/48 h, depending on the spacer structure and being the highest for the conjugate containing the 6‐aminohexanoyl spacer. The rate of Dox release from most conjugates incubated at pH 7.4 (blood pH) was more than 10 times slower, ca. 4–10% of total Dox/48 h. Molecular weight of the polymer (25 000–115 000 g/mol) did not significantly influence the rate. The presence of lysosomal enzyme cathepsin B in incubation media increased the rate of Dox release from the conjugates with oligopeptide GlyLeuGly and Gly‐DL ‐PheLeuGly spacers by 15–30%, whereas the release from conjugates with other spacers remained unchanged. Cytotoxicity of all hydrazone conjugates for mouse EL‐4 T cell lymphoma cells was much higher and close to that of free Dox (IC₅₀ ≈ 0.1–0.34 μg Dox/mL), in contrast to cytotoxicity of similar classic conjugates bearing Dox attached via an amide bond (IC₅₀ ≈ 19 μg Dox/mL).     

Alternating Magnetic Field Controlled Targeted Drug Delivery Based on Graphene Oxide-Grafted Nanosupramolecules

Graphene oxide (GO)-grafted nanosupramolecules have recently emerged as neoteric nano drug carriers in the therapy of refractory diseases. Herein, a multicomponent nanosupramolecular drug carrier based on a targeted peptide and magnetic GO is reported, the drug-release behavior of which can be regulated by an alternating magnetic field (AMF). This multicomponent nanosupramolecular carrier is composed of β-cyclodextrin (β-CD)/nickel nanoparticle-modified graphene oxide (GONiCD) and mitochondrial ion-targeting peptide (MitP)-grafted hyaluronic acid (HAMitP). Owing to the host–guest interaction between β-cyclodextrin and the cyclohexyl groups on MitP, GONiCD and HAMitP could form supramolecular assemblies during the doxorubicin (Dox) loading process, which not only remarkably enhances the drug-loading capacity, but also improves the drug-release efficiency under AMF stimulus. During co-incubation with tumor cells, the Dox-loaded assemblies could strongly target the tumor mitochondria and damage both the mitochondria and the nuclei, owing to Dox release from the assemblies induced by AMF. This study sheds light on the exploration of peptide caps for controlled drug loading/release of supramolecular nanocarriers for efficient drug delivery and anticancer therapy.     

Fabrication of doxorubicin and chlorotoxin-linked Eu-Gd2O3 nanorods with dual-model imaging and targeted therapy of brain tumor

It is urgent to find a technology accurately to better diagnose and treat to brain tumor.Eu-doped Gd2 O3 nanorods(Eu-Gd2 O3 NRs)with paramagnetic and fluorescent properties were conjugated with doxorubicin(Dox)and chlorotoxin(CTX)via PEGylation,hydrazone bond and sulfur bond(named as CTXNRs-Dox),and these NRs could release more Dox in lower pH environment.The results of cell experiments indicated that CTX-NRs-Dox had obvious targeting and toxic effects on U251 cells,as well as good fluorescence imaging behavior.The orthotopic glioma-transplanted mice models were constructed via the intracranial injection of glioma cells(U87 MG).The result of experiments after the tail-vein injection of the prepared NRs suggested that CTX-NRs-Dox could target to brain tumors via the long-time blood circulation,leading to their obvious contrast enhancement of MR imaging of the intracranial tumor and their significant inhibitory effect on the growth and metastasis of brain tumors.A mechanism of synergistic effect of CTX-NRs-Dox on targeting and inhabiting the brain tumor was proposed.Our research suggested that CTX-NRs-Dox had potential application prospect in the detection and treatment of glioma.     

Tumor‐Specific Chemotherapy by Nanomedicine‐Enabled Differential Stress Sensitization

Most of current nanomedicines are administrated intravenously to favour tumor accumulation through enhanced permeability and retention (EPR) effect, which, however, suffers from several drawbacks such as low drug bioavailability and severe side effect. In this work, we have constructed a doxorubicin(Dox)‐based liposomal nanosystem for tumor‐specific chemotherapy, by enabling differential stress sensitization between cancer and normal cells for restricting the chemodrug toxicity exclusively in tumor regions. 2‐Deoxy‐D‐glucose (2DG) was loaded in the nanoliposome to inhibit glycolysis of cancer cells, which works in synergy with the co‐loaded chemodrug Dox to promote mitochondrial depolarization and subsequent apoptosis. In addition, the starvation effect of 2DG can counteract the toxicity of Dox in normal cells and thus mitigates the harmful side effect of chemotherapy. It is expected that such a differential stress sensitization strategy may greatly benefit future nanomedicine design.     

pH-triggered blooming of 'nano-flowers' for tumor intracellular drug delivery

With the decrease in pH value, the 'nano-flower' exhibited a half-open state to expose the target ligands on the surface under tumor acidic conditions and fully bloomed to release Dox under endosomal acidic conditions.     

Tumor-Specific Chemotherapy by Nanomedicine-Enabled Differential Stress Sensitization

Most of current nanomedicines are administrated intravenously to favour tumor accumulation through enhanced permeability and retention (EPR) effect, which, however, suffers from several drawbacks such as low drug bioavailability and severe side effect. In this work, we have constructed a doxorubicin(Dox)-based liposomal nanosystem for tumor-specific chemotherapy, by enabling differential stress sensitization between cancer and normal cells for restricting the chemodrug toxicity exclusively in tumor regions. 2-Deoxy-D-glucose (2DG) was loaded in the nanoliposome to inhibit glycolysis of cancer cells, which works in synergy with the co-loaded chemodrug Dox to promote mitochondrial depolarization and subsequent apoptosis. In addition, the starvation effect of 2DG can counteract the toxicity of Dox in normal cells and thus mitigates the harmful side effect of chemotherapy. It is expected that such a differential stress sensitization strategy may greatly benefit future nanomedicine design.     

Morphology Regulation in Redox Destructible Amphiphilic Block Copolymers and Impact on Intracellular Drug Delivery

In two ABA type amphiphilic block copolymers (P1, P2), the hydrophobic B block consists of a bioreducible segmented poly(disulfide) (PDS), while poly‐N‐isopropylacrylamide (PNIPAM) or poly(triethyleneglycol)methylether‐methacrylate (PTEGMA) serve as the hydrophilic A blocks in P1 and P2, respectively, leading to the formation of polymersome and micelle, owing to the difference in the packing parameters. Both exhibit comparable doxorubicin (Dox) encapsulation efficiency, but glutathione (GSH) triggered release appears much faster from the polymersome than micelle owing to the complete degradation of the PDS segment in polymersome morphology unlike in micelle. Dox‐loaded polymers (P1‐Dox and P2‐Dox) exhibit minimum toxicity to normal cells like C2C12. By contrast, P1‐Dox shows excellent killing efficiency to the HeLa cells (cancer cell) (in which the GSH concentration is significantly higher). However, P2‐Dox reveals a rather poor activity even to HeLa cells. Fluorescence microscopy studies show comparable cellular uptake of P1‐Dox and P2‐Dox. But the polymersome entrapped dye escapes fast from the cargo and reach the nucleus, while the drug‐loaded micelle remains trapped in the perinuclear zone explaining the significant difference in the drug delivery performance of polymersome and micelle.     

Further investigation of the mechanism of Doxorubicin release from P105 micelles using kinetic models

The kinetics of the release of Doxorubicin from Pluronic P105 micelles during ultrasonication and its subsequent re-encapsulation upon cessation of insonation were investigated. Four mechanisms are proposed to explain the acoustically-triggered Doxorubicin (Dox) release and re-encapsulation from Pluronic P105 micelles. The four mechanisms are: micelle destruction; destruction of cavitating nuclei; reassembly of micelles, and the re-encapsulation of Dox. The first mechanism, the destruction of micelles during insonation, causes the release of Dox into solution. The micelles are destroyed because of cavitation events produced by collapsing nuclei, or bubbles in the insonated solution. The second mechanism, the slow destruction of cavitating nuclei, results in a slow partial recovery phase, when a small amount of Dox is re-encapsulated. The third and fourth mechanisms, the reassembly of micelles and the re-encapsulatin of Dox, are independent of ultrasound. These two mechanism are responsible for maintaining the drug release at a partial level, and for recovery after insonation ceases. A normal distribution was used to describe micellar size. Parameters for the model were determined based upon the best observed fit to experimental data. The resulting model provides a good approximation to experimental data for the release of Dox from Pluronic P105 micelles.     

Albumin-Albumin/Lactosylated Core-Shell Nanoparticles: Therapy to Treat Hepatocellular Carcinoma for Controlled Delivery of Doxorubicin

Doxorubicin (Dox) is the most widely used chemotherapeutic agent and is considered a highly powerful and broad-spectrum for cancer treatment. However, its application is compromised by the cumulative side effect of dose-dependent cardiotoxicity. Because of this, targeted drug delivery systems (DDS) are currently being explored in an attempt to reduce Dox systemic side-effects. In this study, DDS targeting hepatocellular carcinoma (HCC) has been designed, specifically to the asialoglycoprotein receptor (ASGPR). Dox-loaded albumin-albumin/lactosylated (core-shell) nanoparticles (tBSA/BSALac NPs) with low (LC) and high (HC) crosslink using glutaraldehyde were synthesized. Nanoparticles presented spherical shapes with a size distribution of 257 ± 14 nm and 254 ± 14 nm, as well as an estimated surface charge of −28.0 ± 0.1 mV and −26.0 ± 0.2 mV, respectively. The encapsulation efficiency of Dox for the two types of nanoparticles was higher than 80%. The in vitro drug release results showed a sustained and controlled release profile. Additionally, the nanoparticles were revealed to be biocompatible with red blood cells (RBCs) and human liver cancer cells (HepG2 cells). In cytotoxicity assays, Dox-loaded nanoparticles decrease cell viability more efficiently than free Dox. Specific biorecognition assays confirmed the interaction between nanoparticles and HepG2 cells, especially with ASGPRs. Both types of nanoparticles may be possible DDS specifically targeting HCC, thus reducing side effects, mainly cardiotoxicity. Therefore, improving the quality of life from patients during chemotherapy.     

Investigation of the local delivery of an intelligent chitosan-based 188Re thermosensitive in situ-forming hydrogel in an orthotopic hepatoma-bearing rat model

In this study, in vitro and in vivo evaluations of the local delivery of ¹⁸⁸Re-Tin colloid and doxorubicin (Dox) through chitosan (C)-based thermosensitive in situ-forming hydrogels by intratumoral injection in an orthotopic hepatoma-bearing rat model were carried out. Selective internal radiation therapy has been increasingly used as an alternative therapy option for hepatocellular carcinoma (HCC) and combined with biodegradable drug carrier systems to improve drug delivery and systemic toxicity. The C-based thermosensitive hydrogel (C/GP), an injectable thermogelling solution crosslinked between C and β-glycerophosphate (GP), was induced as an implanted carrier to combine the ¹⁸⁸Re-Tin colloid and Dox as a novel treatment strategy. The compounded hydrogel characteristics, including the gelation time, controlled release of Dox, and morphology, were examined. In the animal study, the biodistribution, scintigraphy, therapeutic efficacy, and histopathology were also evaluated. The characterization results reveal that C/GP/Dox hydrogels have similar gelation times of 4–4.5 min and pore sizes of as small as 10 μm compared with C/GP hydrogels. The C/GP/Dox/¹⁸⁸Re-Tin colloids have the longest release time for Dox at 2–3 days. In the in vivo experiments, both the biodistribution and scintigraphy studies have the highest hydrogel uptakes in the tumor at different time points, as well as localized radioactivities for a certain time. The therapeutic evaluation indicates that C/GP/Dox/¹⁸⁸Re-Tin colloids can more significantly inhibit tumors compared with the control group at 2 and 4 weeks post-treatment. These results indicate that this novel treatment system is a promising option for inoperable HCC.     

Microfluidic Synthesis of Rigid Nanovesicles for Hydrophilic Reagents Delivery

We present a hollow‐structured rigid nanovesicle (RNV) fabricated by a multi‐stage microfluidic chip in one step, to effectively entrap various hydrophilic reagents inside, without complicated synthesis, extensive use of emulsifiers and stabilizers, and laborious purification procedures. The RNV contains a hollow water core, a rigid poly (lactic‐co‐glycolic acid) (PLGA) shell, and an outermost lipid layer. The formation mechanism of the RNV is investigated by dissipative particle dynamics (DPD) simulations. The entrapment efficiency of hydrophilic reagents such as calcein, rhodamine B and siRNA inside the hollow water core of RNV is ≈90 %. In comparison with the combination of free Dox and siRNA, RNV that co‐encapsulate siRNA and doxorubicin (Dox) reveals a significantly enhanced anti‐tumor effect for a multi‐drug resistant tumor model.     

Controlled release of doxorubicin from electrospun MWCNTs/PLGA hybrid nanofibers

In this study, multiwalled carbon nanotubes (MWCNTs) were used to encapsulate a model anticancer drug, doxorubicin (Dox). Then, the drug-loaded MWCNTs (Dox/MWCNTs) with an optimized drug encapsulation percentage were mixed with poly(lactide-co-glycolide) (PLGA) polymer solution for subsequent electrospinning to form drug-loaded composite nanofibrous mats. The structure, morphology, and mechanical properties of the formed electrospun Dox/PLGA, MWCNTs/PLGA, and Dox/MWCNTs/PLGA composite nanofibrous mats were characterized using scanning electron microscopy (SEM), Fourier transform infrared spectroscopy, and tensile testing. In vitro viability assay and SEM morphology observation of mouse fibroblast cells cultured onto the MWCNTs/PLGA fibrous scaffolds demonstrate that the developed MWCNTs/PLGA composite nanofibers are cytocompatible. The incorporation of Dox-loaded MWCNTs within the PLGA nanofibers is able to improve the mechanical durability and maintain the three-dimensional structure of the nanofibrous mats. More importantly, our results indicate that this double-container drug delivery system (both PLGA polymer and MWCNTs are drug carriers) is beneficial to avoid the burst release of the drug and able to release the antitumor drug Dox in a sustained manner for 42 days. The developed composite electrospun nanofibrous drug delivery system may be used as therapeutic scaffold materials for post-operative local chemotherapy.     

Catanionic solid lipid nanoparticles carrying doxorubicin for inhibiting the growth of U87MG cells

Catanionic solid lipid nanoparticles (CASLNs), loaded with doxorubicin (Dox) and grafted with anti-epithelial growth factor receptor (EGFR) (anti-EGFR/Dox-CASLNs), were applied to suppressing propagation of malignant U87MG cells. U87MG cells were cultured with anti-EGFR/Dox-CASLNs for assessing the cell viability and EGFR expression. When the concentration of catanionic surfactants, containing hexadecyltrimethylammonium bromide and sodium anionic sodium dodecylsulfate, was 1mM, CASLNs entrapped the largest quantity of Dox. The order of cacao butter (CB) in the entrapment efficiency of Dox was 50% CB>0% CB>100% CB. In addition, the release rate of Dox and the antiproliferative effect on U87MG cells were in the following order: 100% CB>0% CB>50% CB. A high level of CB in anti-EGFR/Dox-CASLNs reduced the cytotoxicity to human brain-microvascular endothelial cells. The immunochemical staining revealed that the crosslinked anti-EGFR on the surface of Dox-CASLNs preserved a high specificity in recognizing EGFR on U87MG cells and inducing growth-inhibition effect. The innovated anti-EGFR/Dox-CASLNs can be an effective delivery system with high targeting efficacy against the growth of brain glioblastomas carcinoma.