Stimuli-responsive polymer-doxorubicin conjugate: Antitumor mechanism and potential as nano-prodrug

Stimuli-sensitive polymer prodrug nanocarriers by reversible-deactivation radical polymerization

Polymer prodrugs are based on the covalent linkage of therapeutic molecules to a polymer structure which avoids the problems and limitations commonly encountered with traditional drug-loaded nanocarriers in which drugs are just physically entrapped (e.g., burst release, poor drug loadings). In the past few years, reversible-deactivation radical polymerization (RDRP) techniques have been extensively used to design tailor-made polymer prodrug nanocarriers. This synthesis strategy has received a lot of attention due to the possibility of fine tuning their structural parameters (e.g., polymer nature and macromolecular characteristics, linker nature, physico-chemical properties, functionalization, etc.), to achieve optimized drug delivery and therapeutic efficacy. In particular, adjusting the nature of the drug-polymer linker has enabled the easy synthesis of stimuli-responsive polymer prodrugs for efficient spatiotemporal drug release. In this context, this review article will give an overview of the different stimuli-sensitive polymer prodrug structures designed by RDRP techniques, with a strong focus on the synthesis strategies, the macromolecular architectures and in particular the drug-polymer linker, which governs the drug release kinetics and eventually the therapeutic effect. Their biological evaluations will also be discussed.

Nanoplatform based on carbon nanoparticles loaded with doxorubicin enhances apoptosis by generating reactive oxygen species for effective cancer therapy

At present, due to its wide application and relatively low cost, chemotherapy remains a clinically important cancer treatment option; however, a number of chemotherapeutic drugs have important limitations, such as lack of specificity, high toxicity and side effects, and multi-drug resistance. The emergence of nanocarriers has removed numerous clinical application limitations of certain antitumor chemotherapy drugs and has been widely used in the treatment of tumors with nanodrugs. The present study used carbon nanoparticles (CNPs) as a nanocarrier for doxorubicin (DOX) to form the novel nanomedicine delivery system (CNPs@DOX)was demonstrated by UV-vis and fluorescence spectrophotometry, ζ potential and TEM characterization experiments. The results confirmed the successful preparation of CNPs@DOX nanoparticles with a particle size of 96±17 nm, a wide range of absorption and a negatively charged surface. Furthermore, CNPs@DOX produced more reactive oxygen species and induced apoptosis, and thus exhibited higher cytotoxicity than DOX, which is a small molecule anticancer drug without a nanocarrier delivery system.. The present study provides a strategy for the treatment of tumors with nanomedicine.

Janus ACSP Nanoparticle for Synergistic Chemodynamic Therapy and Radiosensitization

Protective autophagy and DNA damage repair lead to tumor radio-resistance. Some hypoxic tumors exhibit a low radiation energy absorption coefficient in radiation therapy. High doses of X-rays may lead to side effects in the surrounding normal tissues. In order to overcome the radio-resistance and improve the efficacy of radiotherapy based on the characteristics of the tumor microenvironment, the development of radiosensitizers has attracted much attention. In this study, a Janus ACSP nanoparticle (NP) was developed for chemodynamic therapy and radiosensitization. The reactive oxygen species generated by the Fenton-like reaction regulated the distribution of cell cycles from a radioresistant phase to a radio-sensitive phase. The high-Z element, Au, enhanced the production of hydroxyl radicals (•OH) under X-ray radiation, promoting DNA damage and cell apoptosis. The NP delayed DNA damage repair by interfering with certain proteins involved in the DNA repair signaling pathway. In vivo experiments demonstrated that the combination of the copper-ion-based Fenton-like reaction and low-dose X-ray radiation enhanced the effectiveness of radiotherapy, providing a novel approach for synergistic chemodynamic and radiosensitization therapy. This study provides valuable insights and strategies for the development and application of NPs in cancer treatment.

Doxorubicin conjugates: a practical approach for its cardiotoxicity alleviation

INTRODUCTION

Doxorubicin (DOX) emerges as a cornerstone in the arsenal of potent chemotherapeutic agents. Yet, the clinical deployment of DOX is tarnished by its proclivity to induce severe cardiotoxic effects, culminating in heart failure and other consequential morbidities. In response, a panoply of strategies has undergone rigorous exploration over recent decades, all aimed at attenuating DOX's cardiotoxic impact. The advent of encapsulating DOX within lipidic or polymeric nanocarriers has yielded a dual triumph, augmenting DOX's therapeutic efficacy while mitigating its deleterious side effects.

AREAS COVERED

Recent strides have spotlighted the emergence of DOX conjugates as particularly auspicious avenues for ameliorating DOX-induced cardiotoxicity. These conjugates entail the fusion of DOX through physical or chemical bonds with diminutive natural or synthetic moieties, polymers, biomolecules, and nanoparticles. This spectrum encompasses interventions that impinge upon DOX's cardiotoxic mechanism, modulate cellular uptake and localization, confer antioxidative properties, or refine cellular targeting.

EXPERT OPINION

The endorsement of DOX conjugates as a compelling stratagem to mitigate DOX-induced cardiotoxicity resounds from this exegesis, amplifying safety margins and the therapeutic profile of this venerated chemotherapeutic agent. Within this ambit, DOX conjugates stand as a beacon of promise in the perpetual pursuit of refining chemotherapy-induced cardiac compromise.

Targeted Nanoparticles: the Smart Way for the Treatment of Colorectal Cancer

Colorectal cancer (CRC) is a widespread cancer that starts in the digestive tract. It is the third most common cause of cancer deaths around the world. The World Health Organization (WHO) estimates an expected death toll of over 1 million cases annually. The limited therapeutic options as well as the drawbacks of the existing therapies necessitate the development of non-classic treatment approaches. Nanotechnology has led the evolution of valuable drug delivery systems thanks to their ability to control drug release and precisely target a wide variety of cancers. This has also been extended to the treatment of CRC. Herein, we shed light on the pertinent research that has been performed on the potential applications of nanoparticles in the treatment of CRC. The various types of nanoparticles in addition to their properties, applications, targeting approaches, merits, and demerits are discussed. Furthermore, innovative therapies for CRC, including gene therapies and immunotherapies, are also highlighted. Eventually, the research gaps, the clinical potential of such delivery systems, and a future outlook on their development are inspired.

Combination of Chlorambucil and Mercaptopurine Show Effective Anti-Cancer Effects in Mice Model

Background

Combination therapy employing multiple drugs has been shown to enhance the efficacy of cancer treatment. Chlorambucil (Chl) and 6-mercaptopurine (6MP) are the first-line medicines for chronic lymphocytic leukemia and ovarian cancer. However, both were limited by their short half-life of disintegration, unsatisfactory water solubility, and adverse reactions.

Methods

In this work, the drug Chl and 6MP were introduced into the polymerized N-(2-hydroxypropyl) methacrylamide (polyHPMA) by pH and glutathione responsive linker to construct the polymer nanodrug delivery system for effective co-delivery.

Results

The drug load capacities, release, morphology, and cytotoxicity of the pro-drug were systematic. The two drugs showed satisfactory synergism with a combination index of 0.81, and a better ability to induce apoptosis. In and ex vivo fluorescence imaging showed a rapid systemic distribution of the conjugate within mice, majorly metabolized by liver and kidneys and eliminated after 24 hr. No significant pathological damage was observed in the major organs. This polymeric prodrug system holds promise for improved therapeutic efficiency and reduced side effects through the synergistic delivery of various chemotherapeutics.

Conclusion

The introduction of HPMA as a carrier not only enhanced the solubility and biocompatibilities of Chl and 6 MP but also improved their drug effect. This strategy might be a promising alternative for constructing multi-drug-release system.

Comparison of the Therapeutic Efficacy of Antibiotic-Loaded Polymeric Tissue Scaffold and Bone Cement in the Regeneration of Infected Bone Tissue

Background Local antibiotic applications have been used in chronic osteomyelitis and have been defined as an adjunctive treatment method. Biodegradable materials are also used for the same purpose by adding antibiotics. The fact that it does not require additional surgery to be removed is an important advantage. In this study, we intended to develop a new biodegradable drug-loaded polymeric scaffold with good antibiotic release and compare the microbiological results with antibiotic-impregnated bone cement. Methodology A tissue scaffold containing poly(2-hydroxyethyl methacrylate) (PHEMA) was prepared in our laboratory and loaded with ertapenem and daptomycin antibiotics. The surface morphology and pore geometries of drug-loaded and unloaded scaffolds were analyzed by a scanning electron microscope under vacuum. The dose-dependent antiproliferative effects of PHEMA scaffold, drug-loaded scaffold, cement, and drug-loaded cement on osteoblast cells were investigated. To evaluate drug release kinetics, the absorbance values of the scaffold loaded with ertapenem and daptomycin were measured with the spectrometer. For microbiological tests, ertapenem and daptomycin-impregnated cement and scaffold, as well as the control scaffold and cement samples, were investigated for their antibacterial activities on Staphylococcus aureus and Klebsiella pneumoniae strains using the disc diffusion method. These microorganisms are one of the most common microorganisms in osteomyelitis. Results The efficacy of antibiotic-impregnated scaffold and cement on both gram-negative and gram-positive microorganisms was investigated. The daptomycin zone diameter in S. aureus ATCC 29233 strain was 17 mm, whereas it was 24 mm for scaffold and 22 mm for cement. Scaffold was found to be more effective than cement against S. aureus strain. The K. pneumoniae ATCC BAA-2814 strain was found to be resistant to ertapenem, but the zone diameter was 21 mm for scaffold and 20 mm for cement. Ertapenem-loaded scaffold was found to be more effective than cement. It was found that the antimicrobial activity of the scaffold was higher than cement. When we evaluated the release profiles, for the daptomycin-loaded cement group, 98% of daptomycin was cumulatively released within 30 minutes, and for the daptomycin-loaded scaffold group, 100% of daptomycin was cumulatively released in six days. To compare ertapenem-loaded cement and scaffold, 98% of ertapenem was cumulatively released within 10 minutes in the cement group. For the scaffold group, 100% of ertapenem was cumulatively released in 17 days. We found that the scaffold released the antibiotic more slowly and for a longer duration. Therefore, it was thought that the scaffold would be more effective on biofilm and the treatment of osteomyelitis would be more successful. Conclusions The produced scaffold was compared with cement, and it was concluded that the scaffold had better release and antimicrobial efficacy. Scaffold is more advantageous than cement because it is bioeliminable. Thus, there is no need for a second surgical intervention with the likely prevention of mortality and morbidity. Because of all these features, the scaffold seems promising in the local treatment of osteomyelitis.

Hollow Mesoporous Silica Nanoparticles for Dual Chemo-starvation Therapy of Hepatocellular Carcinoma

PURPOSE

This study aims at chemotherapy and starvation therapy of HCC via starvation and apoptosis.

METHODS

Hollow mesoporous organosilica nanoparticles (HMONs) with the thioether-hybrid structure were developed using an organic/inorganic co-templating assembly approach. Hydrofluoric acid was used to remove the internal MSN core for yielding large radial mesopores for loading drug cargos. The morphology and structure of NPs were determined using TEM and SEM. HMONs were stepwise surface modified with glucose oxidase (GOx), oxygen (O2) and Doxorubicin (DOX), and cancer cell membrane (CCM) for yielding CCM-coated HMONs (targeted stealth biorobots; TSBRs) for starvation, apoptotic, and enhanced cell uptake properties, respectively. The surface area and pore size distribution were determined via BET and BJH assays. The catalytic ability of GOx-modified NPs was measured using in vitro glucose conversion approach authenticated by H2O2 and pH determination assays. MTT assay was used to determine the cytotoxicities of NPs. Cell uptake and apoptotic assay were used for the NPs internalization and apoptosis mechanisms. The subcutaneous HepG2 tumor model was established in mice. The long-term in vivo toxicity was determined using blood assays.

RESULTS

The prepared NPs were spherical, hollow and mesoporous with excellent surface area and pore size distribution. The GOx-modified NPs exhibited excellent catalytic activity. The TSBRs showed better cytotoxicity and reduce the tumor size and weight. The NPs showed long-term safety in vivo.

CONCLUSION

TSBRs destroyed cancer cells by starvation and chemotherapy in both in-vitro and in-vivo settings which demonstrates its anti-cancer potential.

Temperature and pH-responsive PNIPAM@PAA Nanospheres with a Core-Shell Structure for Controlled Release of Doxorubicin in Breast Cancer Treatment

Stimuli-responsive polymers have been of great interest in the fabrication of advanced drug delivery systems. In this study, a facile approach was developed to synthesize a dually temperature/pH-responsive drug delivery system with a core-shell structure to control the release of doxorubicin (DOX) at the target site. For this purpose, poly(acrylic acid) (PAA) nanospheres were first synthesized using the precipitation polymerization technique and were used as pH-responsive polymeric cores. Then, poly(N-isopropylacrylamide) (PNIPAM) with thermo-responsivity properties was coated on the outer surface of PAA cores via seed emulsion polymerization technique to render monodisperse PNIPAM-coated PAA (PNIPAM@PAA) nanospheres. The optimized PNIPAM@PAA nanospheres with an average particle size of 116.8 nm (PDI= 0.243), had a high negative surface charge (zeta potential= -47.6 mV). Then, DOX was loaded on PNIPAM@PAA nanospheres and the entrapment efficiency (EE) and drug loading (DL) capacity were measured to be 92.7% and 18.5%, respectively. The drug-loaded nanospheres exhibited a low leakage at neutral pH and physiological temperature, but drug release significantly enhanced at acidic pH (pH= 5.5), indicating the tumor-environment responsive drug release behavior of the prepared nanospheres. Also, kinetics studies showed that, the sustained release of DOX from PNIPAM@PAA nanospheres was consistent with the Fickian diffusion mechanism. Moreover, the anticancer efficacy of DOX-loaded nanospheres was evaluated in vitro against MCF-7 breast cancer cells. The obtained results revealed that, the incorporation of DOX into PNIPAM@PAA nanospheres increases its cytotoxicity against cancer cells compared to the free DOX. Our results suggest that, PNIPAM@PAA nanospheres can be considered as a promising vector to release anticancer drugs with dual-stimuli responsivity to pH and temperature.

Oxidation Responsive PEGylated Polyamino Acid Bearing Thioether Pendants for Enhanced Anticancer Drug Delivery

Reactive oxygen species (ROS) in biological tissues are in a state of dynamic balance. However, many diseases such as cancer and inflammation, are accompanied by a long-term increase in ROS. This situation inspires researchers to use ROS-sensitive nanocarriers for a site-specific release of cargo in pathological areas. Polyamino acid materials with good biodegradability, biocompatibility, and regular secondary structure are widely used in the biomedical field. Herein, a new oxidation responsive PEGylated polyamino acid is synthesised for anticancer drug delivery by ring-opening polymerisation of N-carboxyanhydrides bearing thioether pendants. The obtained block copolymer mPEG-b-PMLG self-assembles into spherical nanoparticles (NPs) in water with diameter ≈68.3 nm. NMR measurement demonstrated that the hydrophobic thioether pendants in the NPs can be selectively oxidised to hydrophilic sulfoxide groups by H₂ O₂ , which will lead to the disassociation of NPs. In vitro drug release results indicated that the encapsulated Nile red is selectively released in the trigger of 10 mM H₂ O₂ in PBS. Finally, anticancer drug doxorubicin (DOX) is encapsulated to the NPs, and the obtained NPs/DOX exhibits an improved antitumor efficacy in 4T1 tumour-bearing mice and lower cardiotoxicity than free DOX. These results indicates that the mPEG-b-PMLG NPs are promising for anticancer drug delivery.

Boosting Doxorubicin-Induced Mitochondria Apoptosis for the Monodrug-Mediated Combination of Chemotherapy and Chemodynamic Therapy

Doxorubicin (Dox)-mediated generation of reactive oxygen radicals (ROS) for mitochondrial apoptosis is identified as a new cytotoxic mechanism in addition to the well-established one via nuclear DNA replication interference. However, this mechanism contributes far less than the latter to Dox therapy. This newly identified pathway to make Dox therapy function like the combination of chemodynamic therapy (CDT) and chemotherapy-mediated by Dox alone would be amplified. One-pot nanoconstruction (HEBD) is fabricated based on the chemical reactions driven assemblies among epigallocatechin gallate (EGCG), buthionine sulfoximine (BSO) and formaldehyde in aqueous mediums followed by Dox adsorption. Acid tumor microenvironments allow the liberation of EGCG, BSO, and Dox due to the breakage of Schiff base bonds. EGCG component in HEBD is responsible for targeting mitochondria and disrupting mitochondrial electron transport chain (mETC) to compel electrons leakage in favor of their capture by Dox to produce more ROS. EGCG-induced mETC disruption results in mitochondrial respiration inhibition with alleviated hypoxia in tumor cells while BSO inhibits glutathione biosynthesis to protect ROS from redox depletion, further boosting Dox-induced CDT. This strategy of amplifying CDT pathway for the Dox-mediated combined therapy could largely improve antitumor effect, extend lifespan of tumor-bearing mice, reduce risks of cardiotoxicity and metastasis.

ROS-responsive Galactosylated-nanoparticles with Doxorubicin Entrapment for Triple Negative Breast Cancer Therapy

Background

Triple negative breast cancer (TNBC) is one of the most aggressive tumors with high metastasis and mortality, which constitutes 15~20% of all breast cancers. Chemotherapy remains main therapeutic option in the treatment of patients with TNBC.

Methods

We developed reactive oxygen species (ROS)-responsive galactosylated nanoparticles (DOX@NPs) as an efficiently targeted carrier for doxorubicin (DOX) delivery to inhibit the growth of TNBC in vitro and in vivo. DOX@NPs were composed of polyacrylate galactose and phenylboronic derivatives conjugation. The in vitro cytotoxicity, cellular uptake, cell apoptosis and cycle distribution of tumor cells treated with different formulations were investigated. Meanwhile in vivo biodistribution and antitumor effects were investigated in a 4T1 tumor-bearing mouse model.

Results

DOX@NPs showed good ROS responsiveness and rapid DOX release in the presence of H₂O₂. Furthermore, our data suggested that DOX@NPs could effectively trigger tumor cells apoptosis and cycle arrest, efficiently accumulate into tumor sites, and suppress tumor growth without adverse side effects.

Conclusion

Our results suggested DOX@NP with potent potential as a promising nanocarrier for TNBC therapy, which deserved further investigation for other cancer treatment.

New Nanosized Systems Doxorubicin-Amphiphilic Copolymers of N-Vinylpyrrolidone and (Di)methacrylates with Antitumor Activity

Nanosized systems of DOX with antitumor activity on the base of micelle-like particles of amphiphilic thermosensitive copolymers of N-vinylpyrrolidone (VP) with triethylene glycol dimethacrylate (TEGDM), and N-vinylpyrrolidone and methacrylic acid (MAA) with TEGDM were explored. They were investigated in aqueous solutions by electron absorption spectroscopy, dynamic light scattering and cyclic voltammetry. Experimental data and quantum-chemical modeling indicated the formation of a hydrogen bond between oxygen-containing groups of monomer units of the copolymers and H-atoms of OH and NH₂ groups of DOX; the energies and H-bond lengths in the considered structures were calculated. A simulation of TDDFT spectra of DOX and its complexes with the VP and TEGDM units was carried out. Electrochemical studies in PBS have demonstrated that the oxidation of encapsulated DOX appeared to be easier than that of the free one, and its reduction was somewhat more difficult. The cytotoxicity of VP-TEGDM copolymer compositions containing 1, 5 and 15 wt% DOX was studied in vitro on HeLa cells, and the values of IC₅₀ doses were determined at 24 and 72 h of exposure. The copolymer compositions containing 5 and 15 wt% DOX accumulated actively in cell nuclei and did not cause visual changes in cell morphology.

pH/redox-responsive core cross-linked based prodrug micelle for enhancing micellar stability and controlling delivery of chemo drugs: An effective combination drug delivery platform for cancer therapy

Core-crosslinking of micelles (CCMs) appears to be a favorable strategy to enhance micellar stability and sustained release of the loaded drug. In this study, the DOX-conjugated pH-sensitive polymeric prodrug Methoxy Poly (ethylene oxide)-b-Poly (Aspartate-Hydrazide) (mPEG-P [Asp-(Hyd-DOX)] was created using ring-opening polymerization. To further enhance the micellar system, 3,3'-diselanediyldipropanoic acid (DSeDPA) was applied to link the hydrophobic segment via click reaction to form pH/redox-responsive CCMs. Dual anti-cancer drugs, DOX as a pro-drug and SN-38 as a targeting drug, were used to enhance inhibition. DLS confirmed that the non-cross-linked micelle (NCMs) showed a higher (96.43 nm) particle size compared to the CCMs (72.63 nm). Due to micellar shrinkage after crosslinking, CCMs displayed SN-38 drug loading (7.32 %) and encapsulation efficiency (86.23 %). The mPEG-P(Asp-Hyd) copolymer's in vitro cytotoxicity on HeLa and HaCaT cell lines found that 84.52 % of the cells are alive, and zebrafish (Danio rerio) embryos and larvae are highly biocompatible. The DOX/SN-38@CCMs had a sustained discharge profile in vitro, unlike the DOX/SN-38@NCMs. In DOX/SN-38@CCMs, HeLa cells were inhibited 50.90 % more than HaCaT (14.25 %) at the maximum drug dose (10 μg/mL). The CCMs successfully targeted and supplied DOX/SN-38 in HeLa cells rather than HaCaT cells, based on cellular uptake of 2D cell culture. CCMs, unlike NCMs, inhibit the growth of spheroids for extended periods of time due to the prolonged release of the loaded drug. Overall, CCMs are good-looking for use as regulated delivery of DOX/SN-38 in cancer cells because of all of these appealing characteristics.

Polymer-drug conjugates: Design principles, emerging synthetic strategies and clinical overview

Adagen, an enzyme replacement treatment for adenosine deaminase deficiency, was the first protein-polymer conjugate to be approved in early 1990s. Post this regulatory approval, numerous polymeric drugs and polymeric nanoparticles have entered the market as advanced or next-generation polymer-based therapeutics, while many others have currently been tested clinically. The polymer conjugation to therapeutic moiety offers several advantages, like enhanced solubilization of drug, controlled release, reduced immunogenicity, and prolonged circulation. The present review intends to highlight considerations in the design of therapeutically effective polymer-drug conjugates (PDCs), including the choice of linker chemistry. The potential synthetic strategies to formulate PDCs have been discussed along with recent advancements in the different types of PDCs, i.e., polymer-small molecular weight drug conjugates, polymer-protein conjugates, and stimuli-responsive PDCs, which are under clinical/preclinical investigation. Current impediments and regulatory hurdles hindering the clinical translation of PDC into effective therapeutic regimens for the amelioration of disease conditions have been addressed.

Tumor microenvironment-responsive versatile "Trojan horse" theranostic nanoplatform for magnetic resonance imaging-guided multimodal synergistic antitumor treatment

A natural killer (NK)-92 cell membrane-camouflaged mesoporous MnO₂-enveloped Au@Pd (Au@Pd@MnO₂) nanoparticles (denoted as APMN NPs)-based versatile biomimetic theranostic nanoplatform was developed for magnetic resonance (MR) imaging-guided multimodal synergistic antitumor treatments. In this core-shell nanostructure, an Au@Pd core induced near-infrared (NIR)-activatable hyperthermal effects and nanozyme catalytic activity, while a mesoporous MnO₂ shell not only afforded a high drug-loading capability, tumor microenvironment (TME)-triggered MR imaging and drug release, but also endowed catalase-, glutathione peroxidase-, and Fenton-like activities. Furthermore, the NK-92 cell membrane camouflaging endowed the NPs with enhanced tumor-targeting capability, immune escape function, and membrane protein-mediated tumoral uptake property. The doxorubicin-loaded APMN (D-APMN) NPs exhibited TME-responsive drug release properties. Furthermore, the cellular uptake, in vivo MR imaging, and NIR thermal imaging confirmed the active tumor-targeting capability and TME-responsive MR imaging property of these biomimetic NPs. An antitumor efficacy test, histological analyses, and blood biochemical profiles suggested that the developed D-APMN NPs possessed a high antitumor activity and biosafety in tumor-bearing nude mice. Therefore, the developed APMN NPs held great potential as an intelligent and comprehensive theranostic nanoplatform for tumor-specific bioimaging and TME-responsive multimodality treatment based on photothermal therapy, chemodynamic therapy, and chemotherapy. STATEMENT OF SIGNIFICANCE: Exploring intelligent and comprehensive theranostic nanoplatforms to integrate tumor-specific bioimaging and TME-responsive multimodal therapy effectively is a challenge. Herein, we successfully developed a new kind of NK-92 cell membrane-camouflaged mesoporous MnO₂-enveloped Au@Pd nanoparticles (APMN NPs)-based versatile biomimetic theranostic nanoplatform for the potential MR imaging-guided multimodal synergistic antitumor treatments. These NPs could integrate unique structural, optical, multiple-catalytic, paramagnetic, and biological merits of NK-92 cell membrane, Au@Pd cores and mesoporous MnO₂ shell in a single nanoplatform. The NK-92 cell membrane camouflaging endowed the NPs with enhanced tumor-targeting capability, immune escape function, and membrane protein-mediated tumoral uptake property. The new information obtained from this study may be beneficial to promote the development of novel TME-responsive versatile "Trojan horse" theranostic nanoplatforms for efficient MR imaging-guided multimodal synergistic treatment.

Green synthesis of DOX-loaded hollow MIL-100 (Fe) nanoparticles for anticancer treatment by targeting mitochondria

Fe-based Metal-Organic Frameworks (MOFs) are promising drug delivery materials due to their large surface area, high stability, and biocompatibility. However, their drug loading capacity is constrained by their small pore size, and a further improvement in their drug capacity is needed. In this work, we report an effective and green structural modification strategy to improve drug loading capacity for Fe-based MOFs. Our strategy is to grow MIL-100 (Fe) on carboxylate-terminated polystyrene (PS-COOH) via a sustainable route, which creates a large inner cavity as well as exposure of more functional groups that benefit drug loading capacity. We perform the scanning electron microscope and transmission electron microscope to confirm the hollow structure of MIL-100 (Fe). Up to 30% of drug loading capacity has been demonstrated in our study. We also conduct cell viability tests to investigate its therapeutic effects on breast cancer cells (MDA-MB-231). Confocal laser scanning microscopy imaging confirms cellular uptake and mitochondrial targeting function of doxorubicin-loaded H-M (DOX@H-M) nanoparticles. JC-1 staining of cancer cells reveals a significant change in the mitochondrial membrane potential, indicating the mitochondrial dysfunction and apoptosis of tumor cells. Our study paves the way for facile synthesis of hollow structural MOFs, and demonstrates the potential of applying Fe-based MOFs in breast cancer treatment.

Stimulus-responsive self-assembled prodrugs in cancer therapy

Small-molecule prodrugs have become the main toolbox to improve the unfavorable physicochemical properties of potential therapeutic compounds in contemporary anti-cancer drug development. Many approved small-molecule prodrugs, however, still face key challenges in their pharmacokinetic (PK) and pharmacodynamic (PD) properties, thus severely restricting their further clinical applications. Self-assembled prodrugs thus emerged as they could take advantage of key benefits in both prodrug design and nanomedicine, so as to maximize drug loading, reduce premature leakage, and improve PK/PD parameters and targeting ability. Notably, temporally and spatially controlled release of drugs at cancerous sites could be achieved by encoding various activable linkers that are sensitive to chemical or biological stimuli in the tumor microenvironment (TME). In this review, we have comprehensively summarized the recent progress made in the development of single/multiple-stimulus-responsive self-assembled prodrugs for mono- and combinatorial therapy. A special focus was placed on various prodrug conjugation strategies (polymer-drug conjugates, drug-drug conjugates, etc.) that facilitated the engineering of self-assembled prodrugs, and various linker chemistries that enabled selective controlled release of active drugs at tumor sites. Furthermore, some polymeric nano-prodrugs that entered clinical trials have also been elaborated here. Finally, we have discussed the bottlenecks in the field of prodrug nanoassembly and offered potential solutions to overcome them. We believe that this review will provide a comprehensive reference for the rational design of effective prodrug nanoassemblies that have clinic translation potential.

Recycling of SLC38A1 to the plasma membrane by DSCR3 promotes acquired temozolomide resistance in glioblastoma

PURPOSE

Glioblastoma multiforme (GBM) is a primary brain tumor with devastating prognosis. Although the O⁶-methylguanine-DNA methyltransferase (MGMT) leads to inherent temozolomide (TMZ) resistance, approximately half of GBMs were sufficient to confer acquired TMZ resistance, which express low levels of MGMT. The purpose of this study was to investigate the underlying mechanisms of the acquired TMZ resistance in MGMT-deficient GBM.

METHODS

The function of Down syndrome critical region protein 3 (DSCR3) on MGMT-deficient GBM was investigated in vitro and in an orthotopic brain tumor model in mice. Purification of plasma membrane proteins by membrane-cytoplasmic separation and subsequent label free-based quantitative proteomics were used to identified potential protein partners for DSCR3. Immunofluorescence was performed to show the reverse transport of solute carrier family 38 member 1 (SLC38A1) mediated by DSCR3.

RESULTS

DSCR3 is upregulated in MGMT-deficient GBM cells during TMZ treatment. Both DSCR3 and SLC38A1 were highly expressed in recurrent GBM patients. Silencing DSCR3 or SLC38A1 expression can increase TMZ sensitivity in MGMT-deficient GBM cells. Combination of proteomics and in vitro experiments show that DSCR3 directly binds internalized SLC38A1 to mediate its sorting into recycling pathway, which maintains the abundance on plasma membrane and enhances uptake of glutamine in MGMT-deficient GBM cells.

CONCLUSIONS

DSCR3 is a crucial regulator of acquired TMZ resistance in MGMT-deficient GBM. The DSCR3-dependent recycling of SLC38A1 maintains its abundance on plasma membrane, leading to tumor progression and acquired TMZ resistance in MGMT-deficient GBM.

Tuning the Hydrophilic-Hydrophobic Balance of Molecular Polymer Bottlebrushes Enhances their Tumor Homing Properties

Nanoparticle (NP)-based drug delivery systems are promising in anticancer therapy, capable of delivering cargo with superior selectivity and achieving enhanced tumor accumulation compared to small-molecule therapeutics. As more efforts are being devoted to NP development, molecular polymer bottlebrushes (MPBs) have gained attention as a potential drug delivery vehicle. To date, the influence of various MPB parameters such as size, shape, and surface charge in determining tumor penetrability have been systematically probed. However, the role of amphiphilicity, specifically the hydrophilic-hydrophobic balance, remains unexplored. In this study, a series of MPBs are employed with varied hydrophobicity levels to reveal a dependence between MPB composition, cell association, and tumor homing. The data indicates that increasing levels of hydrophobicity in MPBs (to a certain level) demonstrate only marginal effects in vitro but reveals enhanced tumor homing in a mouse model of ovarian cancer in vivo, where more hydrophilic MPBs exhibit low tissue deposition and low tumor homing. In contrast, more hydrophobic MPBs show significant tumor accumulation and homing due to their engineered hydrophobicity.

Single and Multiple Stimuli-Responsive Polymer Particles for Controlled Drug Delivery

Polymers that can change their properties in response to an external or internal stimulus have become an interesting platform for drug delivery systems. Polymeric nanoparticles can be used to decrease the toxicity of drugs, improve the circulation of hydrophobic drugs, and increase a drug’s efficacy. Furthermore, polymers that are sensitive to specific stimuli can be used to achieve controlled release of drugs into specific areas of the body. This review discusses the different stimuli that can be used for controlled drug delivery based on internal and external stimuli. Internal stimuli have been defined as events that evoke changes in different characteristics, inside the body, such as changes in pH, redox potential, and temperature. External stimuli have been defined as the use of an external source such as light and ultrasound to implement such changes. Special attention has been paid to the particular chemical structures that need to be incorporated into polymers to achieve the desired stimuli response. A current trend in this field is the incorporation of several stimuli in a single polymer to achieve higher specificity. Therefore, to access the most recent advances in stimuli-responsive polymers, the focus of this review is to combine several stimuli. The combination of different stimuli is discussed along with the chemical structures that can produce it.

Fabrication of hyaluronic acid-based micelles with glutathione-responsiveness for targeted anticancer drug delivery

Hyaluronic acid (HA), a natural polymer, has gained much attention recently because of its good biocompatibility and extensive availability. Herein, a novel drug delivery system based on hyaluronic acid-tetraphenyl ethylene conjugate (HA-SS-TPE) with glutathione (GSH)-responsiveness for targeted drug delivery is designed. During the self-assembly of HA-SS-TPE, doxorubicin (DOX) is loaded to form DOX-loaded polymeric micelles. These as-prepared DOX-loaded polymeric micelles not only exhibit fluorescent emission, but also fast glutathione-triggered dissociation to unload DOX by responding to tumor microenvironments. In-vitro investigations showed that the DOX-loaded polymeric micelles presented a higher intracellular release ratio in CD44-positive cells (ES2 and Hela) than in CD44-negative cells (MCF-7 and L929). Notably, in vivo investigations showed that DOX@HA-SS-TPE significantly suppressed tumor growth. As a result, such a GSH-responsive drug delivery system with fluorescent feature provides a potential treatment for CD44-overexpressing cancers.

An Efficient Carbon-Based Drug Delivery System for Cancer Therapy through the Nucleus Targeting and Mitochondria Mediated Apoptotic Pathway

The emergence of nanocarriers solves the problems of antitumor drugs such as non-targeting, huge side effects, etc., and has been widely used in tumor therapy. Some kinds of antitumor drugs such as doxorubicin (DOX) mainly act on the nucleic acid causing DNA damage, interfering with transcription, and thereby disrupting or blocking the process of cancer cell replication. Herein, a new nanodrug delivery system, the carbon-based nanomaterials (CBNs)-Pluronic F127-DOX (CPD), is designed by using CBNs as a nanocarrier for DOX. As a result, the tumor growth inhibition rate of CPD group is as high as 79.42 ± 2.83%, and greatly reduces the side effects. The targeting rate of the CPD group of DOX in the tumor nucleus is 36.78%, and the %ID/g in tumor tissue is 30.09%. The CPD regulates the expression levels of Caspase-3, p53, and Bcl-2 genes by increasing intracellular reactive oxygen species (ROS) levels and reducing mitochondrial membrane potential, which indicates that mitochondrial-mediated pathways are involved in apoptosis. The CPD nanodrug delivery system increases the effective accumulation of DOX in tumor cell nuclei and tumor tissues, and generates massive ROS, thereby inhibiting tumor growth in vivo, representing a promising agent for anticancer applications.

Targeted delivery by pH-responsive mPEG-S-PBLG micelles significantly enhances the anti-tumor efficacy of doxorubicin with reduced cardiotoxicity

Stimuli-responsive nanotherapeutics hold great promise in precision oncology. In this study, a facile strategy was used to develop a new class of pH-responsive micelles, which contain methoxy polyethylene glycol (mPEG) and poly(carbobenzoxy-l-glutamic acid, BLG) as amphiphilic copolymer, and β-thiopropionate as acid-labile linkage. The mPEG-S-PBLG copolymer was synthesized through one-step ring-opening polymerization (ROP) and thiol-ene click reaction, and was able to efficiently encapsulate doxorubicin (DOX) to form micelles. The physicochemical characteristics, cellular uptake, tumor targeting, and anti-tumor efficacy of DOX-loaded micelles were investigated. DOX-loaded micelles were stable under physiological conditions and disintegrated under acidic conditions. DOX-loaded micelles can be internalized into cancer cells and release drugs in response to low pH in endosomes/lysosomes, resulting in cell death. Furthermore, the micellar formulation significantly prolonged the blood circulation, reduced the cardiac distribution, and selectively delivered more drugs to tumor tissue. Finally, compared with free DOX, DOX-loaded micelles significantly improved the anti-tumor efficacy and reduced systemic and cardiac toxicity in two different tumor xenograft models. These results suggest that mPEG-S-PBLG micelles have translational potential in the precise delivery of anti-cancer drugs.

Description of Release Process of Doxorubicin from Modified Carbon Nanotubes

The article discusses the release process of doxorubicin hydrochloride (DOX) from multi-wall carbon nanotubes (MWCNTs). The studies described a probable mechanism of release and actions between the surface of functionalized MWCNTs and anticancer drugs. The surface of carbon nanotubes (CNTs) has been modified via treatment in nitric acid to optimize the adsorption and release process. The modification efficiency and physicochemical properties of the MWCNTs+DOX system were analyzed by using SEM, TEM, EDS, FTIR, Raman Spectroscopy and UV-Vis methods. Based on computer simulations at pH 7.4 and the experiment at pH 5.4, the kinetics and the mechanism of DOX release from MWNT were discussed. It has been experimentally observed that the acidic pH (5.4) is appropriate for the efficient release of the drug from CNTs. It was noted that under acidic pH conditions, which is typical for the tumour microenvironment almost 90% of the drug was released in a relatively short time. The kinetics models based on different mathematical functions were used to describe the release mechanism of drugs from MWCNTs. Our studies indicated that the best fit of experimental kinetic curves of release has been observed for the Power-law model and the fitted parameters suggest that the drug release mechanism of DOX from MWCNTs is controlled by Fickian diffusion. Molecular dynamics simulations, on the other hand, have shown that in a neutral pH solution, which is close to the blood pH, the release process does not occur keeping the aggregation level constant. The presented studies have shown that MWCNTs are promising carriers of anticancer drugs that, depending on the surface modification, can exhibit different adsorption mechanisms and release.

Nanoparticulation of Prodrug into Medicines for Cancer Therapy

This article provides a broad spectrum about the nanoprodrug fabrication advances co-driven by prodrug and nanotechnology development to potentiate cancer treatment. The nanoprodrug inherits the features of both prodrug concept and nanomedicine know-how, attempts to solve underexploited challenge in cancer treatment cooperatively. Prodrugs can release bioactive drugs on-demand at specific sites to reduce systemic toxicity, this is done by using the special properties of the tumor microenvironment, such as pH value, glutathione concentration, and specific overexpressed enzymes; or by using exogenous stimulation, such as light, heat, and ultrasound. The nanotechnology, manipulating the matter within nanoscale, has high relevance to certain biological conditions, and has been widely utilized in cancer therapy. Together, the marriage of prodrug strategy which shield the side effects of parent drug and nanotechnology with pinpoint delivery capability has conceived highly camouflaged Trojan horse to maneuver cancerous threats.

Dynamic precise dual-drug-backboned nano-prodrugs for selective chemotherapy

To achieve an ideal drug delivery platform with precise composition and high tumor selectivity, the PEGylated dual-drug backboned prodrug was synthesized via the copolymerization between diamine monomer of ortho ester and cisplatin- demethylcantharidin conjugate (Pt(IV)-1), and then terminated by mPEG550-active ester. The amphipathic prodrug could self-assemble into nano-prodrugs, which endowed the precise structure and high drug loading. Moreover, the nano-prodrugs exhibited physicochemical stability at physiological pH (7.4) for stable blood circulation, DePEGylation and dynamic size change for selective tumor accumulation and enhanced cellular internalization at tumoral extracellular pH (6.8), and efficient drug release for synergetic apoptosis and cytotoxicity at tumoral intracellular pH (5.0)/glutathione. Thus, the precise dual-drug backboned nano-prodrugs with detachable PEGylation, dynamic size change and efficient drug release could be potentially translated for clinically selective cancer treatment. STATEMENT OF SIGNIFICANCE: Few nanomedicines have been clinically used for cancer treatment and little progress has been made in the last decades due to the unprecise composition and unsatisfactory tumor selectivity. Herein, the PEGylated dual-drug backboned nano-prodrugs were successfully constructed by rational design and endowed the defined structure, precise drug ratio, extraordinary high drug loading and reduction/pH dual sensitivity. The nano-prodrugs further exhibited the stable storage and blood circulation through PEGylation and low critical micelle concentration, enhanced tumor accumulation and cellular uptake via extracellular DePEGylation and dynamic size translation, and synergetic cytotoxicity via intracellular efficient drug release, respectively. This study can open a new avenue for easy industrial manufacture and quality control, and highly selective chemotherapy appealing for clinical translation. .

Triple negative breast cancer and non-small cell lung cancer: Clinical challenges and nano-formulation approaches

Triple negative breast cancer (TNBC) and non-small cell lung cancer (NSCLC) are amongst the most aggressive forms of solid tumors. TNBC is highlighted by absence of genetic components of progesterone receptor, HER2/neu and estrogen receptor in breast cancer. NSCLC is characterized by integration of malignant carcinoma into respiratory system. Both cancers are associated with poor median and overall survival rates with low progression free survival with high incidences of relapse. These cancers are characterized by tumor heterogeneity, genetic mutations, generation of cancer-stem cells, immune-resistance and chemoresistance. Further, these neoplasms have been reported for tumor cross-talk into second primary cancers for each other. Current chemotherapeutic regimens include usage of multiple agents in tandem to affect tumor cells through multiple mechanisms with various such combinations being clinically tested. However, lack of controlled delivery and effective temporospatial presence of chemotherapeutics has resulted in suboptimal therapeutic response. Consequently, passive targeted albumin bound paclitaxel and PEGylated liposomal doxorubicin have been clinically used and tested with newer drugs for improved therapeutic efficacy in these cancers. Active targeting of nanocarriers against surface overexpressed proteins in both neoplasms have been explored. However, use of single agent nanoparticulate formulations against both cancers have failed to elicit desired outcomes. This review aims to identify clinical unmet need in these cancers while establishing a correlation with tested nano-formulation approaches and issues with preclinical to clinical translation. Lipid and polymer-based drug-drug and drug-gene combinatorial nanocarriers delivering multiple chemotherapeutics simultaneously to desired site of action have been detailed. Finally, emerging opportunities such as pharmacological targets (immune check point and epigentic modulators) as well as gene-based modulation (siRNA/CRISPR/Cas9) and the nano-formulation challenges for effective treatment of both cancers have been explored.

Amphiphilic branched polymer-nitroxides conjugate as a nanoscale agent for potential magnetic resonance imaging of multiple objects in vivo

BACKGROUND

In order to address the potential toxicity of metal-based magnetic resonance imaging (MRI) contrast agents (CAs), a concept of non-metallic MRI CAs has emerged. Currently, paramagnetic nitroxides (such as (2,2,5,5-tetramethylpyrrolidine-1-oxyl, PROXYL), (2,2,6,6-tetramethylpiperidine-1-oxide, TEMPO), etc.) are being extensively studied because their good stability and imaging mechanism are similar to metal-based contrast agents (such as Gd3+ chelate-based clinical CAs). However, a lower relaxivity and rapid in vivo metabolism of nitroxides remain to be addressed. Previous studies have demonstrated that the construction of macromolecular nitroxides contrast agents (mORCAs) is a promising solution through macromolecularization of nitroxides (i.e., use of large molecules to carry nitroxides). Macromolecular effects not only increase the stability of nitroxides by limiting their exposure to reductive substances in the body, but also improve the overall 1H water relaxation by increasing the concentration of nitroxides and slowing the molecular rotation speed.

RESULTS

Branched pDHPMA-mPEG-Ppa-PROXYL with a high molecular weight (MW = 160 kDa) and a nitroxides content (0.059 mmol/g) can form a nanoscale (~ 28 nm) self-assembled aggregate in a water environment and hydrophobic PROXYL can be protected by a hydrophilic outer layer to obtain strong reduction resistance in vivo. Compared with a small molecular CA (3-Carboxy-PROXYL (3-CP)), Branched pDHPMA-mPEG-Ppa-PROXYL displays three prominent features: (1) its longitudinal relaxivity (0.50 mM- 1 s- 1) is about three times that of 3-CP (0.17 mM- 1 s- 1); (2) the blood retention time of nitroxides is significantly increased from a few minutes of 3-CP to 6 h; (3) it provides long-term and significant enhancement in MR imaging of the tumor, liver, kidney and cardiovascular system (heart and aortaventralis), and this is the first report on nitroxides-based MRI CAs for imaging the cardiovascular system.

CONCLUSIONS

As a safe and efficient candidate metal-free magnetic resonance contrast agent, Branched pDHPMA-mPEG-Ppa-PROXYL is expected to be used not only in imaging the tumor, liver and kidney, but also the cardiovascular system, which expands the application scope of these CAs.

Dual responsive dextran-graft-poly (N-isopropylacrylamide)/doxorubicin prodrug via Schiff base reaction

Stimulus-responsive nanoparticles stand out in studies for cancer treatment since these systems can promote a selective release of the drug in tumor tissues and cells, minimizing the effects caused by conventional chemotherapy. Dextran-graft-poly (N-isopropylacrylamide) copolymers were synthesized via Schiff base formation. The synthesis of copolymers was confirmed by Fourier transform infrared spectroscopy (FTIR) and proton nuclear magnetic resonance (NMR) and the analyses of dynamic light scattering (DLS) showed that the copolymers were thermal and pH dual-responsive. The chemotherapy drug doxorubicin (DOX) was conjugated to the copolymers via Schiff base formation, obtaining nanoparticles by self-assembling with size smaller than 130 nm. A higher percentage of doxorubicin was released at pH 5.0 (59.1 ± 2.1%) compared to physiological pH (34.9 ± 4.8%), confirming a pH-sensitive release profile. The in vitro cytotoxicity assay demonstrated that DOX-loaded nanoparticles can inhibit cancer cell proliferation and promote reduced cytotoxicity in non-tumor cells. The D_45kP_30k-DOX nanoparticles induced morphological changes in HCT-116 cells suggesting cell death and the cell uptake assay indicated that the nanoparticles can be internalized by endocytosis. Therefore, DOX-loaded nanoparticles exhibited potential as smart systems for cancer treatment.

Smart Stimuli-Responsive and Mitochondria Targeting Delivery in Cancer Therapy

Dysfunction in the mitochondria (Mc) contributes to tumor progression. It is a major challenge to deliver therapeutic agents specifically to the Mc for precise treatment. Smart drug delivery systems are based on stimuli-responsiveness and active targeting. Here, we give a whole list of documented pathways to achieve smart stimuli-responsive (St-) and Mc-targeted DDSs (St-Mc-DDSs) by combining St and Mc targeting strategies. We present the formulations, targeting characteristics of St-Mc-DDSs and clarify their anti-cancer mechanisms as well as improvement in efficacy and safety. St-Mc-DDSs usually not only have Mc-targeting groups, molecules (lipophilic cations, peptides, and aptamers) or materials but also sense the surrounding environment and correspondingly respond to internal biostimulators such as pH, redox changes, enzyme and glucose, and/or externally applied triggers such as light, magnet, temperature and ultrasound. St-Mc-DDSs exquisitely control the action site, increase therapeutic efficacy and decrease side effects of the drug. We summarize the clinical research progress and propose suggestions for follow-up research. St-Mc-DDSs may be an innovative and sensitive precision medicine for cancer treatment.

A Mini-Review on Nano Technology in the Tumour Targeting Strategies: Drug Delivery to Cancer Cells

BACKGROUND

Recently, the application of cancer nanotechnology-based drug delivery to cancer cells has arisen as an important method to resolve multiple molecular, biophysical, and biochemical obstacles, which the body is preparing to resist against the productive implementation of chemotherapeutic medications. Drug delivery technologies focused on nanoparticles, which have resolved some of the drawbacks of conventional chemotherapy as, decreased drug viscosity, chemo-resistance, precise malignity, limited medicative measures with low oral bioactivity. Due to their adjustable size and surface properties, the half-life period of a drug can be increased in the bloodstream.

OBJECTIVE

The aim of the current study is to collect and document the data available on the drug delivery system for anticancer drugs. The present study includes some of the drug carriers like liposomes, carbon dots, micelles, carbon nanotubes, magnetic nanoparticles, etc. Methods: To write this review, an exhaustive literature survey was carried out using relevant work published in various SCI, Scopus, and non-SCI indexed journals. The different search engines used to download the research/ review papers are Google search, PubMed, Science Direct, Google Scholar, Scientific Information Database and Research Gate, etc. Results: Nanotechnology offers better pharmacokinetics, reduces the systematic toxicities related to the chemotherapies and a better route of drug administration. In the analysis, we critically highlight recent studies on carcinoma-fighting nanotechnology.

CONCLUSION

In the present study, different kinds of nano-based drug delivery systems have been discussed along with their characteristic features, the encapsulation of anticancer agents into different types of nanometresized vehicles and their general mechanism.

Targeted delivery system using silica nanoparticles coated with chitosan and AS1411 for combination therapy of doxorubicin and antimiR-21

Herein, a novel targeted delivery system was developed for intracellular co-delivery of doxorubicin (DOX) as a chemotherapeutic drug, antimiR-21 as an oncogenic antagomiR. In this system, DOX was loaded into mesoporous silica nanoparticles (MSNs) and chitosan was applied to cover the surface of MSNs. AS1411 aptamer as targeting nucleolin and antimiR-21 were electrostatically attached onto the surface of the chitosan-coated MSNs and formed the final nanocomplex (AACS nanocomplex). The study of drug release was based on DOX release under pH 7.4 and 5.5. Cellular toxicity and cellular uptake assessments of AACS nanocomplex were carried out in nucleolin positive (C26, MCF-7, and 4T1) and nucleolin negative (CHO) cell lines using MTT assay and flow cytometry analysis, respectively. Also, Anti-tumor efficacy of AACS nanocomplex was evaluated in C26 tumor-bearing mice. Overall, the results show that the combination therapy of DOX and antimiR-21, using AACS nanocomplex, could combat the cancer cell growth rate.

Bacterium-mimicking sequentially targeted therapeutic nanocomplexes based on O-carboxymethyl chitosan and their cooperative therapy by dual-modality light manipulation

An integrated gene nanovector capable of overcoming complicated physiological barriers in one vector is desirable to circumvent the challenges imposed by the intricate tumor microenvironment. Herein, a nuclear localization signals (NLS)-decorated element and an iRGD-functionalized element based on O-carboxymethyl chitosan were synthesized, mixed, and coated onto PEI/DNA to fabricate bacterium-mimicking sequentially targeted therapeutic nanocomplexes (STNPs) which were internalized through receptor-mediated endocytosis and other pathways and achieved nuclear translocation of DNA. The endo/lysosomal membrane disruption triggered by reactive oxygen species (ROS) after short-time illumination, together with the DNA nuclear translocation, evoked an enhanced gene expression. Alternatively, the excessive ROS from long-time irradiation induced apoptosis in tumor cells, bringing about greater anti-tumor efficacy owing to the integration of gene and photodynamic therapy. Overall, these results demonstrated bacterium-mimicking STNPs could be a potential candidate for tumor treatments.

Phthalocyanine-Conjugated Glyconanoparticles for Chemo-photodynamic Combination Therapy

Combination cancer therapy based on multifunctional nanomaterials has attracted great attention. The present work focuses on the preparation of the glycopolymeric nanoparticle, which contains a photosensitizer (zinc(II)phthalocyanine, ZnPc) and an anticancer drug (Doxorubicin, Dox). First, a novel mono azide-functional ZnPc-N₃ with seven hydrophilic ethylene oxide chains was synthesized. Next, ZnPc alone or together with Dox bearing glycopolymers was synthesized via the RAFT polymerization method and then self-assembled into glyconanoparticles (GNPs) with narrow particle size distribution. Then the evaluation of the biological activity of GNPs (GNPs-ZnPc and GNPs-ZnPc/Dox) for dual photodynamic therapy (PDT) and chemotherapy against human breast cancer cells was investigated. The constructed GNPs were identified via general characterization methods, including dynamic light scattering (DLS) and transmission electron microscopy (TEM). The prepared GNPs-ZnPc/Dox demonstrated remarkable photophysical and photochemical properties, involving good colloidal stability in biological conditions, pH-responsive drug release, and the capacity to generate singlet oxygen under light irradiation. The outer layer of nanoparticles covered by fructose sugar moieties achieves a targeted cancer therapy owing to GLUT5 (a well-known fructose transporter) overexpression toward breast cancer cells. In vitro experiments were then performed to evaluate the chemo/phototoxicity, cellular uptake, and anticancer efficacy of GNPs-ZnPc/Dox. In comparison with free Dox, human breast cancer cells treated with GNPs-ZnPc/Dox exhibited a higher cellular internalization via GLUT5 targeting. In particular, the GNPs-ZnPc/Dox nanoplatform revealed an excellent synergistic anticancer activity in comparison with free ZnPc-N₃ and free Dox, representing a novel and promising chemo-photodynamic combination therapeutic methodology to improve therapeutic efficacy.

Active-targeting and acid-sensitive pluronic prodrug micelles for efficiently overcoming MDR in breast cancer

Multidrug resistance (MDR) seriously hinders therapeutic efficacy in clinical cancer treatment. Herein, we reported new polymeric prodrug micelles with tumor-targeting and acid-sensitivity properties based on two different pluronic copolymers (F127 and P123) for enhancing tumor MDR reversal and chemotherapy efficiency in breast cancer. Hybrid micelles were composed of phenylboric acid (PBA)-modified F127 (active-targeting group) and doxorubicin (DOX)-grafted P123 (prodrug groups), which were named as FBP-CAD. FBP-CAD exhibited good stability in a neutral environment and accelerated drug release under mildly acidic conditions by the cleavage of β-carboxylic amides bonds. In vitro studies demonstrated that FBP-CAD significantly increased cellular uptake and drug concentration in MCF-7/ADR cells through the homing ability of PBA and the anti-MDR effect of P123. In vivo testing further indicated that hybrid micelles facilitated drug accumulation at tumor sites as well as reduced side effects to normal organs. The synergistic effect of active-targeting and MDR-reversal leads to the highest tumor growth inhibition (TGI 78.2%). Thus, these multifunctional micelles provide a feasible approach in nanomedicine for resistant-cancer treatment.

Reconstituted high density lipoprotein (rHDL), a versatile drug delivery nanoplatform for tumor targeted therapy

rHDL is a synthesized drug delivery nanoplatform exhibiting excellent biocompatibility, which possesses most of the advantages of HDL. rHDL shows almost no toxicity and can be degraded to non-toxic substances in vivo. The severe limitation of the application of various antitumor agents is mainly due to their low bioavailability, high toxicity, poor stability, etc. Favorably, antitumor drug-loaded rHDL nanoparticles (NPs), which are known as an important drug delivery system (DDS), help to change the situation a lot. This DDS shows an outstanding active-targeting ability towards tumor cells and improves the therapeutic effect during antitumor treatment while overcoming the shortcomings mentioned above. In the following text, we will mainly focus on the various applications of rHDL in tumor targeted therapy by describing the properties, preparation, receptor active-targeting ability and antitumor effects of antineoplastic drug-loaded rHDL NPs.

Poly(ester-thioether) microspheres co-loaded with erlotinib and α-tocopheryl succinate for combinational therapy of non-small cell lung cancer

Polymer microspheres are attracting wide attention in localized cancer therapy owing to the excellent biocompatibility and drug loading capacity, controllable biodegradation speeds, and minimized systemic toxicity. Herein, we presented poly(ester-thioether) microspheres, porous and nonporous, as drug depots for localized therapy of non-small cell lung cancer (NSCLC). Specifically, erlotinib and α-tocopheryl succinate (α-TOS), which are respectively an epidermal growth factor receptor (EGFR) inhibitor and mitochondria destabilizer, were efficiently loaded into porous and nonporous poly(ester-thioether) microspheres for the treatment of EGFR-overexpressing NSCLC (A549 cells). The poly(ester-thioether) microspheres significantly improved the bioavailability of both erlotinib and α-TOS in comparison to the free drug combination, realizing synergistic inhibition of A549 cells both in vitro and in vivo. The porous microspheres displayed faster degradation and drug release than the nonporous counterpart, thereby showing better anticancer efficacy. Overall, our study reported a new anticancer strategy of erlotinib and α-TOS combination for therapy of NSCLC, and established that poly(ester-thioether) microspheres could be a robust and biodegradable reservoir for drug delivery and localized cancer therapy.

Biodegradable Polymeric Nanoparticles for Drug Delivery to Solid Tumors

Advances in nanotechnology have favored the development of novel colloidal formulations able to modulate the pharmacological and biopharmaceutical properties of drugs. The peculiar physico-chemical and technological properties of nanomaterial-based therapeutics have allowed for several successful applications in the treatment of cancer. The size, shape, charge and patterning of nanoscale therapeutic molecules are parameters that need to be investigated and modulated in order to promote and optimize cell and tissue interaction. In this review, the use of polymeric nanoparticles as drug delivery systems of anticancer compounds, their physico-chemical properties and their ability to be efficiently localized in specific tumor tissues have been described. The nanoencapsulation of antitumor active compounds in polymeric systems is a promising approach to improve the efficacy of various tumor treatments.

Cathepsin B-responsive and gadolinium-labeled branched glycopolymer-PTX conjugate-derived nanotheranostics for cancer treatment

Multi-modal therapeutics are emerging for simultaneous diagnosis and treatment of cancer. Polymeric carriers are often employed for loading multiple drugs due to their versatility and controlled release of these drugs in response to a tumor specific microenvironment. A theranostic nanomedicine was designed and prepared by complexing a small gadolinium chelate, conjugating a chemotherapeutic drug PTX through a cathepsin B-responsive linker and covalently bonding a fluorescent probe pheophorbide a (Ppa) with a branched glycopolymer. The branched prodrug-based nanosystem was degradable in the tumor microenvironment with overexpressed cathepsin B, and PTX was simultaneously released to exert its therapeutic effect. The theranostic nanomedicine, branched glycopolymer-PTX-DOTA-Gd, had an extended circulation time, enhanced accumulation in tumors, and excellent biocompatibility with significantly reduced gadolinium ion (Gd³⁺) retention after 96 h post-injection. Enhanced imaging contrast up to 24 h post-injection and excellent antitumor efficacy with a tumor inhibition rate more than 90% were achieved from glycopolymer-PTX-DOTA-Gd without obvious systematic toxicity. This branched polymeric prodrug-based nanomedicine is very promising for safe and effective diagnosis and treatment of cancer.

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A cathepsin B-responsive theranostic nanomedicine (glycopolymer-PTX-DOTA-Gd) based on a branched glycopolymer was prepared.

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Glycopolymer-PTX-DOTA-Gd can be specifically degradated and release drug at tumor enviornment.

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Glycopolymer-PTX-DOTA-Gd enhance the contrast of magnetic resonance imaging (MRI) at tumor sites.

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The nanomedicine have good biocompatibility, excellent tumor targeting and anti-tumor efficacy.

Towards precision nanomedicine for cerebrovascular diseases with emphasis on Cerebral Cavernous Malformation (CCM)

Introduction: Cerebrovascular diseases encompass various disorders of the brain vasculature, such as ischemic/hemorrhagic strokes, aneurysms, and vascular malformations, also affecting the central nervous system leading to a large variety of transient or permanent neurological disorders. They represent major causes of mortality and long-term disability worldwide, and some of them can be inherited, including Cerebral Cavernous Malformation (CCM), an autosomal dominant cerebrovascular disease linked to mutations in CCM1/KRIT1, CCM2, or CCM3/PDCD10 genes.Areas covered: Besides marked clinical and etiological heterogeneity, some commonalities are emerging among distinct cerebrovascular diseases, including key pathogenetic roles of oxidative stress and inflammation, which are increasingly recognized as major disease hallmarks and therapeutic targets. This review provides a comprehensive overview of the different clinical features and common pathogenetic determinants of cerebrovascular diseases, highlighting major challenges, including the pressing need for new diagnostic and therapeutic strategies, and focusing on emerging innovative features and promising benefits of nanomedicine strategies for early detection and targeted treatment of such diseases.Expert opinion: Specifically, we describe and discuss the multiple physico-chemical features and unique biological advantages of nanosystems, including nanodiagnostics, nanotherapeutics, and nanotheranostics, that may help improving diagnosis and treatment of cerebrovascular diseases and neurological comorbidities, with an emphasis on CCM disease.

A GSH-Responsive Nanoprodrug System Based on Self-Assembly of Lactose Modified Camptothecin for Targeted Drug Delivery and Combination Chemotherapy

Background

Conventional chemotherapy using small molecular antitumor drugs suffers from several limitations, for instance poor water solubility, high toxicity, and lack of specificity. However, prodrugs constructed by covalent modification of anticancer drugs can overcome these limitations, which are able to release its active form after entering the tumor tissues by specific stimulus response.

Methods

A GSH-responsive glyco-nanoprodrug system has been constructed by self-assembled of amphiphilic lactosemodified camptothecin prodrug molecular (Lac-SS-CPT) for targeting drug delivery and combination therapy.

Results

Using HL7702 cells as experimental models, the cytotoxic effects of Lac-SS-CPT were investigated to 10–30 µmol/L for 48 hours. Notably, the cell viability of Lac-SS-CPT to HL7702 cells was higher compared with free CPT which indicated that Lac-SS-CPT can reduce side-effects. Simultaneously, we have evaluated the anticancer efficiency of doxorubicin hydrochloride (DOX)-loaded Lac-SS-CPT glyco-nanoprodrug system (Lac-SS-CPT@DOX), where Lac-SS-CPT@DOX and free DOX incubated with HpeG2 cells and HL7702 cells for 24, 48, and 72 hours, respectively. It turned out that Lac-SS-CPT@DOX encapsulated anticancer drug (DOX) could decrease DOX side-effect on HL7702 cells and increase DOX anticancer efficiency. More importantly, the CPT and DOX were released from Lac-SS-CPT@DOX in HepG2 cells where a higher GSH concentration exists. Moreover, combination therapy efficiency was evaluated, where free DOX and Lac-SS-CPT@DOX incubated with DOX-resistance HepG2 cells (HepG2-ADR cells), respectively.

Conclusion

The results revealed that the Lac-SS-CPT@DOX could enhance the cytotoxicity of DOX for HepG2-ADR cells and provided a new idea for designing an advanced nano-prodrug system toward combination therapy.

Synthesis and In Vitro Assessment of pH-Sensitive Human Serum Albumin Conjugates of Pirarubicin

In a previous study, we reported on the development of a synthetic polymer conjugate of pirarubicin (THP) that was formed via an acid-labile hydrazone bond between the polymer and the THP. However, the synthetic polymer itself was non-biodegradable, which could lead to unexpected adverse effects. Human serum albumin (HSA), which has a high biocompatibility and good biodegradability, is also a potent carrier for delivering antitumor drugs. The objective of this study was to develop pH-sensitive HSA conjugates of THP (HSA-THP), and investigate the release of THP and the cytotoxicity under acidic conditions in vitro for further clinical development. HSA-THP was synthesized by conjugating maleimide hydrazone derivatives of THP with poly-thiolated HSA using 2-iminothiolane, via a thiol-maleimide coupling reaction. We synthesized two types of HSA-THP that contained different amounts of THP (HSA-THP2 and HSA-THP4). Free THP was released from both of the HSA conjugates more rapidly at an acidic pH, and the rates of release for HSA-THP2 and HSA-THP4 were similar. Moreover, both HSA-THPs exhibited a higher cytotoxicity at acidic pH than at neutral pH, which is consistent with the effective liberation of free THP under acidic conditions. These findings suggest that these types of HSA-THPs are promising candidates for further development.

Synergistic Combination Chemotherapy of Lung Cancer: Cisplatin and Doxorubicin Conjugated Prodrug Loaded, Glutathione and pH Sensitive Nanocarriers

Purpose

Prodrug technology-based combination drug therapy has been exploited as a promising treatment strategy to achieve synergistic lung cancer therapy, reduce drug dose, and decrease side effects. In the present study, we synthesized a pH and glutathione (GSH) sensitive prodrug, cisplatin (CIS) and doxorubicin (DOX) conjugates (CIS-DOXp). CIS-DOXp was loaded by nanocarriers and delivered into the tumor site.

Methods

pH and GSH sensitive CIS-DOX prodrug (CIS-DOXp) was synthesized by conjugating GSH responsive CIS prodrug with pH sensitive DOX prodrug. CIS-DOXp-loaded nanocarriers (CIS-DOXp NC) were prepared using emulsification and solvent evaporation method. The morphology, particle size, polydispersity index (PDI) and zeta potential of nanocarriers were measured. In vitro cytotoxicity of nanocarriers and the corresponding free drugs was examined using the MTT assay. In vivo anti-tumor efficiency and biodistribution behaviors were evaluated on lung cancer mice models.

Results

The size, PDI, zeta potential, CIS loading efficiency, and DOX loading efficiency of CIS-DOXp NC were 128.6 ± 3.2 nm, 0.196 ± 0.021, 15.7 ± 1.7 mV, 92.1 ± 2.1%, and 90.4 ± 1.8%, respectively. The best cell killing ability (the lowest combination index of 0.57) was found at the combination ratio of 1:3 (CIS:DOX, w/w) in the drugs co-loaded formulations, indicating the strongest synergism effect. CIS-DOXp NC showed the best tumor inhibition efficiency (79.9%) in mice with negligible body weight lost.

Conclusion

CIS-DOXp NC could be applied as a promising system for the synergistic chemotherapy of lung cancer.

Glycodendron/pyropheophorbide-a (Ppa)-functionalized hyaluronic acid as a nanosystem for tumor photodynamic therapy

To enhance the drug delivery efficiency of hyaluronic acid (HA), we designed and prepared glycodendron and pyropheophorbide-a (Ppa)-functionalized HA (HA-Ppa-Dendron) as a nanosystem for cancer photodynamic therapy. Linear Ppa-modified HA (HA-Ppa) was also prepared as a control. Cellular uptake of both polymers by MDA-MB-231 cells led to mitochondrial dysfunction and generation of reactive oxygen species under the irradiation of a laser. Compared to the linear polymer, HA-Ppa-Dendron had higher molecular weight, a more compact nanoscale particle size, and a dendritic structure, resulting in a much longer blood circulation time and higher tumor accumulation. HA-Ppa-Dendron outperformed HA-Ppa in inhibiting cell growth, with 60 % of tumors was eradicated under laser irradiation. Tumor growth inhibition (TGI) up to 99.2 % was achieved from HA-Ppa-Dendron, which was much higher than that of HA-Ppa (50.6 %). Therefore, glycodendron-functionalized HAs by integration of HA and dendritic polymers may act as efficient anti-cancer nanomedicine.