Redox-responsive Nanoparticles Research Articles

Novel CD44-Targeted Albumin Nanoparticles: An Innovative Approach to Improve Breast Cancer Treatment.

This study introduces novel CD44-targeted and redox-responsive nanoparticles (FNPs), proposed as doxorubicin (DOX) delivery devices for breast cancer. A cationized and redox-responsive Human Serum Albumin derivative was synthesized by conjugating Human Serum Albumin with cystamine moieties and then ionically complexing it with HA. The suitability of FNPs for cancer therapy was assessed through physicochemical measurements of size distribution (mean diameter of 240 nm), shape, and zeta potential (15.4 mV). Nanoparticles possessed high DOX loading efficiency (90%) and were able to trigger the drug release under redox conditions of the tumor environment (55% release after 2 h incubation). The use of the carrier increased the cytotoxic effect of DOX by targeting the CD44 protein. It was shown that, upon loading, the cytotoxic effect of DOX was enhanced in relation to CD44 protein expression in both 2D and 3D models. DOX@FNPs significantly decrease cellular metabolism by reducing both oxygen consumption and extracellular acidification rates. Moreover, they decrease the expression of proteins involved in the oxidative phosphorylation pathway, consequently reducing cellular viability and motility, as well as breast cancer stem cells and spheroid formation, compared to free DOX. This new formulation could become pioneering in reducing chemoresistance phenomena and increasing the specificity of DOX in breast cancer patients.

PEGylated mesoporous silica core–shell redox-responsive nanoparticles for delivering paclitaxel to breast cancer cells

Controlling the drug release and restricting its presence in healthy organs is extremely valuable. In this study, mesoporous silica nanoparticles (MSN) as the core, loaded with paclitaxel (PTX), were coated with a non-porous silica shell functionalized with disulfide bonds. The nanoparticles were further coated with polyethylene glycol (PEG) via disulfide linkages. We analyzed the physicochemical properties of nanoparticles, including hydrodynamic size via Dynamic Light Scattering (DLS), zeta potential, X-ray Diffraction (XRD) patterns, Fourier-Transform Infrared (FTIR) spectra, and imaging through Transmission Electron Microscopy (TEM) and Scanning Electron Microscopy (SEM). The drug release profile in two distinct glutathione (GSH) concentrations of 2 µM and 10 µM was measured. The cellular uptake of nanoparticles by MCF-7 cell line was determined using Confocal Laser Scanning Microscopy (CLSM) images and flow cytometry. Furthermore, the cell viability and the capability of nanoparticles to induce apoptosis in MCF-7 cell line were studied using the MTT assay and flow cytometry, respectively. Our investigations revealed that the release of PTX from the drug delivery system was redox-responsive. Also, results indicated an elevated level of cellular uptake and efficient induction of apoptosis, underscoring the promising potential of this redox-responsive drug delivery system for breast cancer therapy.

Antitumor effects of redox-responsive nanoparticles containing platinum（Ⅳ）in ovarian cancer

Objectives: To explore the antitumor effects of redox-responsive nanoparticles containing platinum(Ⅳ)-NP@Pt(Ⅳ) in ovarian cancer. Methods: Redox-responsive polymer carriers were synthesized. Polymer carriers and platinum(Ⅳ)-Pt(Ⅳ) can self-assemble into NP@Pt(Ⅳ). Inductively coupled plasma mass spectrometry was performed to detect the platinum release from NP@Pt(Ⅳ) in reducing environment and the platinum content in ovarian cancer cells ES2 treated with cisplatin, Pt(Ⅳ) and NP@Pt(Ⅳ). The proliferation ability of the ovarian cancer cells were detected by 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Cellular apoptosis was assessed by flow cytometry. Collection of primary ovarian cancer tissues from patients with primary high-grade serous ovarian cancer who were surgically treated at the Cancer Hospital of the Chinese Academy of Medical Sciences from October to December 2022. The high-grade serous ovarian cancer patient-derived xenograft (PDX) mice were intravenously injected with Cy7.5 labeled NP@Pt(Ⅳ) followed by in vivo imaging system. Mice were treated with PBS, cisplatin and NP@Pt(Ⅳ). Tumor volume and weight were measured in each group. Necrosis, apoptosis and cell proliferation of tumor tissues were detected by hematoxylin-eosin (HE) staining, TUNEL fluorescence staining and Ki-67 immunohistochemistry staining. Body weight and HE staining of heart, liver, spleen, lung and kidney of mice in each group were measured. Results: The platinum release of NP@Pt(Ⅳ) after 48 hours in reducing environment was 76.29%, which was significantly higher than that of 26.82% in non-reducing environment (P<0.001). The platinum content in ES2 cells after 4 hours and 7 hours of treatment with NP@Pt(Ⅳ) (308.59, 553.15 ng/million cells) were significantly higher than those of Pt(Ⅳ) (100.21, 180.31 ng/million cells) and cisplatin (43.36, 50.36 ng/million cells, P＜0.05). The half inhibitory concentrations of NP@Pt(Ⅳ) in ovarian cancer cells ES2, A2780, A2780DDP were 1.39, 1.42 and 4.62 μmol/L, respectively, which were lower than those of Pt(IV) (2.89, 7.27, and 16.74 μmol/L) and cisplatin (5.21, 11.85, and 71.98 μmol/L). The apoptosis rate of ES2 cells treated with NP@Pt(Ⅳ) was (33.91±3.80)%, which was significantly higher than that of Pt(Ⅳ) [(16.28±2.41)%] and cisplatin [(15.01±1.17)%, P＜0.05]. In high-grade serous ovarian cancer PDX model, targeted accumulation of Cy7.5 labeled NP@Pt(Ⅳ) at tumor tissue could be observed. After the treatment, the tumor volume of mice in NP@Pt(IV) group was (130±98) mm3, which was significantly lower than those in control group [(1 349±161) mm3, P<0.001] and cisplatin group [(715±293) mm3, P=0.026]. The tumor weight of mice in NP@Pt(IV) group was (0.17±0.09)g, which was significantly lower than those in control group [(1.55±0.11)g, P<0.001] and cisplatin group [(0.82±0.38)g, P=0.029]. The areas of tumor necrosis and apoptosis in mice treated with NP@Pt(Ⅳ) were higher than those in mice treated with cisplatin. Immunohistochemical staining revealed that there were low expressions of Ki-67 at tumor tissues of mice treated with NP@Pt(Ⅳ) compared with cisplatin. The change in body weight of mice in NP@Pt(Ⅳ) group was not significantly different from that of the control group [(18.56±2.04)g vs.(20.87±0.79)g, P=0.063]. Moreover, the major organs of the heart, liver, spleen, lung, and kidney were also normal by HE staining. Conclusion: Redox-responsive NP@Pt(Ⅳ), produced in this study can enhance the accumulation of cisplatin in ovarian cancer cells and improve the efficacy of ovarian cancer chemotherapy.

Dual-responsive nanoparticles constructed using light- and redox-responsive linkages

Light- and redox-responsive nanoparticles were synthesized using a simple one-pot emulsion polymerization utilizing mild thiol-disulfide exchange reactions to direct the self-assembly process.

Folic acid-targeted redox responsive polylactic acid-based nanoparticles co-delivering pirarubicin and salinomycin suppress breast cancer tumor growth in vivo.

Targeted cancer therapy using nanocarriers has emerged as a promising solution to the majority of drawbacks associated with conventional chemotherapy. The present research work describes the development of folic acid (FA)-targeted redox responsive [S-(PLA-b-PEG-CONH)]2 polymeric nanoparticles for the co-delivery of pirarubicin (Pira) and salinomycin (Sal). The nanoparticles' redox responsiveness arises from embedded disulfide bonds within the polymer, which gradually break in response to high GSH levels in tumors, enabling sustained drug release. The nanoparticles exhibited a hydrodynamic size of ∼104 nm and a surface charge density of -15.5 mV with low PDI values. Blank nanoparticles (w/o drug) showed negligible toxicity towards both non-malignant human and murine cells and exhibited excellent stability under different environmental conditions for up to 3 weeks. A cellular internalization study conducted using Rho B/C6 dual-dye-encapsulated nanoparticles showed efficient uptake of the nanoparticles after just 1 hour of incubation with SUM-149 2D adherent cells and 3D spheroids. The release of Pira and Sal from Pira/Sal dual-loaded nanoparticles increased significantly in a reducing environment. The % cumulative release of Pira increased from 20.5% ± 1.0 in PBS (pH 7.4) to 40.1% ± 0.4 in dithiothreitol (DTT) after 20 days; similarly, the % cumulative release of Sal increased from 36.2% ± 1.7 in PBS (pH 7.4) to 51.5% ± 1.7 in DTT. The cytotoxicity studies of FA-targeted Pira/Sal dual-loaded nanoparticles with varying Pira : Sal ratios (1 : 1, 3 : 1 and 1 : 3) revealed that the nanoparticles displayed 8-10 fold lower IC50 values than the respective free drug formulations across multiple breast cancer cell lines including SUM-149, MDA-MB-231 and EAC as well as in 3D mammospheres. Balb/c syngeneic mice bearing EAC tumors experienced ∼100% tumor regression upon treatment with FA-targeted Pira/Sal (3 : 1) dual-loaded nanoparticles, indicating synergistic anti-tumor potency. In vivo survival and histopathological studies indicated no significant toxicity in vital organs of the body as compared to free drugs. Based on the performance, the currently investigated FA-targeted Pira/Sal dual-loaded nano-formulation is recommended to be further explored in other cancer types as well as in higher animals for cancer therapy.

Abstract A032: Cell membrane coated- Biomimetic biodegradable nanoparticles for tumor targeted delivery of THP-doxorubicin using polylactic acid based redox responsive polymer

Abstract Chemotherapy is a widely used systemic treatment modality for cancer treatment as it kills the rapidly dividing cells. However, the administered chemo-drugs cause systemic toxicity, have fast degradation rate at physiological conditions hence low bioavailability and poor tumor accumulation. These shortcomings can be mitigated by the use of tumor targeting drug delivery systems. The nanoparticles can further be tailor made according to physiological conditions of the tumor microenvironment. Herein, the redox responsive polymer has been synthesized by introducing the disulphide linkage in the polymer. The drug release profile indicated the release of the drug is more efficient in presence of 10mM Dithiothreitol(reducing agent for disulphide linkage) when compared to 0mM dithiothreitol. In this context, this study investigates the therapeutic efficacy of THP-doxorubicin encapsulated in polylactic acid based redox responsive nanoparticle(NP) whose surface have been modified with tumor (4T1) and macrophage (J774) cell membranes. The coated cell membrane provides advantages such as immune escape, long blood circulation time, specific molecular recognition and cell targeting. The prepared nanoparticles have a hydrodynamic size of 210±10 nm with zeta potential of -30±3 mV. The cellular internalization studies of free drug vs the cell membrane coated NPs (CMNPs) were done and it was confirmed that CMNPs were internalized more efficiently in one hour drug incubation study. The same was confirmed when cancer cell proliferation inhibition assay was done, and half maximal inhibitory concentration of free drug, uncoated NPs and CMNPs were 0.31µM , 0.463µM and 0.137µM respectively. This study provides the synthesis and characterization of redox responsive polymer, preparation of cell membrane coated nanoparticles and in-vitro studies for the same. This study has a future scope in the field of personalized medicine at much cheaper price when compared to active targeting methods by antibodies, CART, proteins etc. Citation Format: Harshdeep Kaur, Harpal Singh, Neetu Singh. Cell membrane coated- Biomimetic biodegradable nanoparticles for tumor targeted delivery of THP-doxorubicin using polylactic acid based redox responsive polymer [abstract]. In: Proceedings of the AACR-NCI-EORTC Virtual International Conference on Molecular Targets and Cancer Therapeutics; 2023 Oct 11-15; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2023;22(12 Suppl):Abstract nr A032.

CD-44 active cystamine-bridged hyaluronic acid-polydopamine nanoparticles for chemo-photothermal cancer therapy

The development of targeted drug delivery systems for cancer treatment has been a topic of great interest in recent years. We developed redox-responsive, NIR-activated, cystamine-bridged hyaluronan-polydopamine (Cys-HA-PDA) nanoparticles (NPs) loaded with doxorubicin (Dox) that bind to CD44 receptors on cancer cells and exhibit enhanced anticancer efficacy due to a chemo-photothermal effect under redox conditions. Synthesized Cys-HA-PDA NPs at 200 µg/mL concentration produced a temperature of 59.5 ℃ at 2 W/cm2, which destroyed tumor cells. The presence of disulfide bonds in Cys-HA-PDA NPs resulted in self-degradability in the cytosol of cancer cells. Furthermore, electrostatic interactions and pi-pi stacking allowed Dox to be successfully encapsulated in Cys-HA-PDA nanoparticles; calculated maximum drug loading and encapsulation efficiency were 21.6% and 88.3%, respectively. The anticancer activity of Dox-loaded NPs on HepG2 cancer cells was increased under NIR laser light (800 nm, 2 W/cm2). Furthermore, interaction with CD44 receptor enhanced the intracellular uptake of Dox-loaded Cys-HA-PDA NPs by HepG2 cells. Overall, the study shows that the use of redox-responsive nanoparticles for CD44-targeted drug delivery is a promising anticancer strategy.

Redox responsive polymeric nanoparticles enhance the efficacy of cyclin dependent kinase 7 inhibitor for enhanced treatment of prostate cancer

Traditional therapies such as surgery and endocrine therapy no longer meet the clinical needs in prostate cancer treatment, and more effective treatments are urgently required. Recent studies have reported that targeted inhibition of the transcription factor cyclin dependent kinase 7 (CDK7) could effectively suppress prostate cancer progression. However, the toxicity of CDK7 inhibitors such as THZ1 is the main limitation of the clinical application. In this work, we synthesized Cys8E (C8E) nanoparticles (NPs) loaded with THZ1 (C8E@THZ1), a novel GSH-targeting and stimuli-responsive nano-delivery platform, and investigated its anti-tumor potential and biosafety properties. In vitro, C8E@THZ1 potently inhibited the proliferation and promoted the apoptosis of prostate cancer cells. On tumor-bearing mice, C8E@THZ1 inhibited tumors by up to 85%, while the damage of THZ1 to liver function was effectively avoided. These results confirmed that inhibition of CDK7 can effectively block the progression of prostate cancer, and that Cys8E NPs is a highly prospective delivery platform to promote the clinical application of CDK7 inhibitors.

Encapsulation of an Antioxidant in Redox-Sensitive Self-Assembled Albumin Nanoparticles for the Treatment of Hepatitis.

Hepatitis is an inflammation of the liver caused by the inadequate elimination of reactive oxygen species (ROS) derived from Kupffer cells. Edaravone is clinically used as an antioxidant but shows poor liver distribution. Herein, we report on the design of a Kupffer cell-oriented nanoantioxidant based on a disulfide cross-linked albumin nanoparticle containing encapsulated edaravone (EeNA) as a therapeutic for the treatment of hepatitis. Since the edaravone is bound to albumin, this results in a soluble and stable form of edaravone in water. Exchanging the intramolecular disulfide bonds to intermolecular disulfide bridges of albumin molecules allowed the preparation of a redox responsive albumin nanoparticle that is stable in the blood circulation but can release drugs into cells. Consequently, EeNA was fabricated by the nanoscale self-assembly of edaravone and albumin nanoparticles without the additives that are contained in commercially available edaravone preparations. EeNA retained its nanostructure under serum conditions, but the encapsulated edaravone was released efficiently under intracellular reducing conditions in macrophages. The EeNA was largely distributed in the liver and subsequently internalized into Kupffer cells within 60 min after injection in a concanavalin-A-induced hepatitis mouse. The survival rate of the hepatitis mice was significantly improved by EeNA due to the suppression of liver necrosis and oxidative stress by scavenging excessive ROS. Moreover, even through the postadministration, EeNA showed an excellent hepatoprotective action as well. In conclusion, EeNA has the potential for use as a nanotherapeutic against various types of hepatitis because of its Kupffer cell targeting ability and redox characteristics.

Biochemical reprogramming of active-targeting and redox responsive nanoparticles for enhancing selective internalization

Selective internalization is urgently needed in accelerating drug release. Herein, the synergistic DOX@PBA-COS/γ-PGA nanoparticles with GGT/SA activate-targeting and pH-H2O2 sensitivities were successively synthetized through the entanglement of chitosan oligosaccharide (COS) chains with phenylboronic acid (PBA) and poly (γ-glutamic acid) (γ-PGA). DOX@PBA-COS/γ-PGA was highly susceptible to gamma-glutamyl transpeptidase (GGT)-targeting than sialic acid (SA)-targeting in HepG2 cells. The selective internalization of DOX@PBA-COS/γ-PGA in the order of HepG2＞HeLa＞MCF-7, due to the clathrin-mediated endocytosis and microtubule polymerization/vesicular transport in HepG2 cells. The innovative strategies to augment selective internalization through the synergistic γ-PGA shielding and redox homeostasis interference provide enlightenment in the hepatocellular carcinoma therapy.

Cysteine-Based Redox-Responsive Nanoparticles for Fibroblast-Targeted Drug Delivery in the Treatment of Myocardial Infarction.

Upon myocardial infarction (MI), activated cardiac fibroblasts (CFs) begin to remodel the myocardium, leading to cardiac fibrosis and even heart failure. No therapeutic approaches are currently available to prevent the development of MI-induced pathological fibrosis. Most pharmacological trials fail from poor local drug activity and side effects caused by systemic toxicity, largely due to the lack of a heart-targeted drug delivery system that is selective for activated CFs. Here, we developed a reduced glutathione (GSH)-responsive nanoparticle platform capable of targeted delivering of drugs to activated CFs within the infarct area of a post-MI heart. Compared with systemic drug administration, CF-targeted delivery of PF543, a sphingosine kinase 1 inhibitor identified in a high-throughput antifibrotic drug screening, had higher therapeutic efficacy and lower systemic toxicity in a MI mouse model. Our results provide a CF-targeted strategy to deliver therapeutic agents for pharmacological intervention of cardiac fibrosis.

PH/redox-responsive self-assembling nanoparticles for combinatorial delivery of 5 fluorouracil and methotrexate in colon cancer therapy

To fulfil the synergistic delivery and on-demand drug release of 5-fluorouracil (5-FU) and methotrexate (MTX) at tumor sites, we innovatively synthesized pH and redox responsive self-assembling nanoparticles based on ZIF-8 frameworks as the 5-FU vehicle decorated with hyaluronic acid-MTX bioconjugates linked with a redox-responsive disulfide bond. The constructed HA-SS-MTX/5-FU@ZIF-8 nanoplatform exhibited monodisperse and spherical shape with a mean hydrodynamic diameter of 161.0nm and loaded about 0.345 g of 5-FU and 0.0508 g of MTX per gram. The preliminary in vitro experiments showed that the as-prepared HA-SS-MTX/5-FU@ZIF-8 nanoparticles (NPs) displayed high inhibiting proliferation and promoting apoptosis performance towards the colon cancer cells.

Study of Cytotoxicity and Internalization of Redox-Responsive Iron Oxide Nanoparticles on PC-3 and 4T1 Cancer Cell Lines.

Redox-responsive and magnetic nanomaterials are widely used in tumor treatment separately, and while the application of their combined functionalities is perspective, exactly how such synergistic effects can be implemented is still unclear. This report investigates the internalization dynamics of magnetic redox-responsive nanoparticles (MNP-SS) and their cytotoxicity toward PC-3 and 4T1 cell lines. It is shown that MNP-SS synthesized by covalent grafting of polyethylene glycol (PEG) on the magnetic nanoparticle (MNP) surface via SS-bonds lose their colloidal stability and aggregate fully in a solution containing DTT, and partially in conditioned media, whereas the PEGylated MNP (MNP-PEG) without S-S linker control remains stable under the same conditions. Internalized MNP-SS lose the PEG shell more quickly, causing enhanced magnetic core dissolution and thus increased toxicity. This was confirmed by fluorescence microscopy using MNP-SS dual-labeled by Cy3 via labile disulfide, and Cy5 via a rigid linker. The dyes demonstrated a significant difference in fluorescence dynamics and intensity. Additionally, MNP-SS demonstrate quicker cellular uptake compared to MNP-PEG, as confirmed by TEM analysis. The combination of disulfide bonds, leading to faster dissolution of the iron oxide core, and the high-oxidative potential Fe3+ ions can synergically enhance oxidative stress in comparison with more stable coating without SS-bonds in the case of MNP-PEG. It decreases the cancer cell viability, especially for the 4T1, which is known for being sensitive to ferroptosis-triggering factors. In this work, we have shown the effect of redox-responsive grafting of the MNP surface as a key factor affecting MNP-internalization rate and dissolution with the release of iron ions inside cancer cells. This kind of synergistic effect is described for the first time and can be used not only in combination with drug delivery, but also in treatment of tumors responsive to ferroptosis.

Histopathological impact of Redox-responsive methacrylamide based micellar nanoparticles on Orthotopic Models of Triple Negative Breast Cancers

The therapeutic efficacy of anticancer nanocarriers ishighly dependent on their size, shape, targeting ability, andstimuli-responsiveness. Herein, we studied the in vivo therapeutic efficacy ofDoxorubicin (Dox) loaded redox responsive micellar-like nanoparticles (MNPs)based on linear 2-hydroxypropyl methacrylamide (HPMA) via histopathologicalevaluations. The therapeutic efficacy of DOX-loaded micellar-like Nanoparticlessignificantly improved while the side effects reduced as confirmed byhistopathological examinations. H&amp;amp;E and tunnel staining of tumor tissuesindicated the higher population of apoptotic tumor cells in both treatmentgroups containing DOX. These redox responsive crosslinked&amp;nbsp;HPMA-basedmicellar-like nanoparticles with acceptable therapeutic efficacy and apoptosisinduction in cancerous cells proved to be promising nanomedicine for breast cancer chemotherapy.

Self-assembled albumin nanoparticles for redox responsive release of curcumin

The synthesis of stimuli-responsive protein-based nanocarriers often involves multi-step processing or use of toxic crosslinkers, which impede their wide-spread utilization as drug delivery systems. In this study, we report a facile, self-assembly based method for the synthesis of redox responsive albumin nanocarriers (<150 nm) without the use of crosslinkers. Curcumin (CUR) was encapsulated into these self-assembled albumin nanoparticles with 83.22% encapsulation efficiency and 8.33% loading capacity. These CUR loaded redox responsive albumin nanoparticles displayed glutathione (GSH) triggered CUR release due to the reduction of disulfide bonds in the protein structure. The release studies show that in the presence of GSH, 61% of the CUR is released, whereas in GSH-free environment only 18% of the drug is released within the first 12 h. In vitro studies performed on triple negative human breast cancer cells (MDA-MB-231) show that encapsulation of CUR provided enhanced cytotoxicity compared to free CUR. Furthermore, studies on the mitochondrial structure of these cells confirm that the drug loaded nanoparticles lead to the changes in mitochondria stress conditions by reacting with the GSH in the cells.

Redox-responsive nanoparticles enhance radiation therapy by altering multifaceted radio-resistance mechanisms in human castration-resistant prostate cancer cells and xenografts

IntroductionRadiation therapy (RT) is a major modality for the treatment of prostate cancer (PCa), especially castration-resistant PCa (CRPC). However, hypoxia, often seen in PCa tumors, leads to radiation-resistance. This work investigates the effect of a novel oxygen-generating polymer-lipid manganese dioxide nanoparticle (PLMDs) on improving RT outcomes in CRPC xenograft models by modulating the tumor microenvironment (TME) both before and after RT. Materials and methodsHuman PC3 and DU145 PCa cells were used to investigate clonogenic inhibition and DNA repair pathways in vitro. Tumor hypoxia and post-RT angiogenesis were evaluated in a PC3-bearing SCID mouse model. PC3 and DU145 xenografts were used to study the efficacy of PLMD in combination with single or fractionated RT. ResultsPLMD plus RT significantly inhibited clonogenic potential, increased DNA double-strand breaks, and reduced DNA damage repair in hypoxic PC3 and DU145 cells as compared to RT alone. PLMD significantly reduced hypoxia-positive areas, hypoxia induced factor 1α (HIF-1α) expression, and protein carbonyl levels (a measure of oxidative stress). Application of PLMD with RT decreased RT-induced angiogenic biomarkers by up to 3-fold. Treatment of the human CRPC xenografts with PLMD plus RT (single or fractionated doses) significantly prolonged median survival of the host compared to RT alone resulting in up to a 40% curative rate. ConclusionPLMD treatment modulated TME and sensitized hypoxic human CRPC cells to RT thus enhancing the efficacy of RT. These results confirmed the potential of PLMD as an adjuvant to RT for the treatment of hypoxic CRPC.

Recent advances in redox-responsive nanoparticles for combined cancer therapy.

The combination of multiple therapeutic modalities has attracted increasing attention as it can achieve better therapeutic effects through different treatment mechanisms. However, traditional small molecule agents are non-specific to the tumor tissue, which leads to off-target toxic effects for healthy tissues. To solve this problem, a number of stimuli-responsive nanoscale drug-delivery systems have been developed. Among these stimuli, a high concentration of reactive oxygen species (ROS) and glutathione (GSH) are characteristic of the tumor microenvironment (TME), which can distinguish it from normal tissue. In this review, we summarize the redox-responsive nanoparticles (NPs) reported in the past three years classified by different functional groups, including GSH-responsive disulfide, ditelluride, and multivalent metal ions, ROS-responsive thioketal, arylboronic ester, aminoacrylate, and bilirubin as well as GSH/ROS dual-responsive diselenide and dicarbonyl thioethers. The prospects and challenges of redox-responsive NPs are also discussed.

An in vitro investigation of the hepatic toxicity of PEGylated polymeric redox responsive nanoparticles.

It can be challenging to deliver drugs to cancer cells in a targeted manner at an effective dose. Polymeric nanoparticles (NPs) are promising drug delivery systems that can be targeted to cancer cells using redox responsive elements. More specifically, intracellular and extracellular levels of the antioxidant glutathione (GSH) are elevated in cancer cells and therefore the use of NPs with a cleavable GSH-responsive element allowing these NPs to target cancer cells and trigger the release of their cargo (e.g. anticancer drugs). The aim of this study was to assess the hepatotoxicity of polymeric NP delivery systems with and without a redox sensitive element. Copolymer poly (lactic-co-glycolic acid) (PLGA) and polyethylene glycol (PEG) NPs with (RR-NPs) and without (nRR-NPs) a redox responsive dithiylethanoate ester linker were synthesised and their toxicity assessed in vitro. As the liver is a primary site of NP accumulation, the C3A hepatocyte cell line was used to assess NP toxicity in vitro via investigation of cytotoxicity, cytokine production, genotoxicity, intracellular reactive oxygen species (ROS) production, intracellular calcium concentration, and hepatocyte function (albumin and urea production). The cellular uptake of NPs was also assessed as this may influence the cellular dose and, therefore, the cellular response. Both NPs had no detrimental impact on cell viability. However, both NPs stimulated an increase in cytokine (IL-1ra) and ROS production and decreased hepatocyte function, with the greatest effect observed for nRR-NPs. Only nRR-NPs caused DNA damage. Cells internalised both NPs and caused a (sub-lethal) increase in intracellular calcium levels. Therefore, whilst the NPs did not have a negative impact on cell viability, the NPs were able to elicit sub-lethal toxicity. By using a battery of tests we were able to demonstrate that RR-NPs may be less toxic than nRR-NPs. Our findings can therefore feed into the development of safer and more effective nanomedicines and into the design of testing strategies to assess polymeric NP safety based on knowledge of their mechanism of toxicity.

LncRNA Uc003xsl.1-Mediated Activation of the NFκB/IL8 Axis Promotes Progression of Triple-Negative Breast Cancer.

These findings identify an epigenetic-driven NFκB/IL8 cascade initiated by a lncRNA, whose aberrant activation contributes to tumor metastasis and poor survival in patients with triple-negative breast cancer.

Mature dendritic cell-derived dendrosomes swallow oxaliplatin-loaded nanoparticles to boost immunogenic chemotherapy and tumor antigen-specific immunotherapy.

The cytomembrane-derived delivery platform represents a promising biomimetic strategy in oncotherapy. To achieve durable and reliable tumor inhibition, mature dendrosomes (mDs), which were isolated from bone marrow-derived dendritic cells undergoing CT26 tumor antigen (TA) stimulation, were fused with redox-responsive nanoparticles (NPs) that were composed of poly(disulfide ester amide) polymers with an intensified disulfide density and hydrophobic oxaliplatin (OXA) prodrugs with the ability to potentiate immunogenicity. In vitro and in vivo results revealed that NP/mDs could induce tumor cell death through mitochondrial pathway and thus created immunogenic microenvironments, but also elicited immunocyte differentiation by TA cross-dressing and infiltration by direct presentation. By further neutralizing immune-regulatory interaction, the administration of PD-L1 antibody (αPD-L1) greatly improved antitumor efficiency of NP/mDs. Furthermore, the effectors of host immune systems effectively inhibited the growth and metastasis of distal tumors, likely because the autologous TA evoked by OXA and allogeneic TA delivered by mDs acted as additional stimuli to reinforce the immune response of tumor-specific T cells and immunosurveillance toward oncogenesis. These results demonstrated that NP/mDs could simultaneously realize immunogenic chemotherapeutics and specific TA delivery. In combination with αPD-L1, the antitumor effect was further enhanced. Therefore, NP/mDs provide a promising strategy for the comprehensive treatment of malignancy.