Development of an oral nanotherapeutics using redox nanoparticles for treatment of colitis-associated colon cancer

Toward a Nanoencapsulated EPR Imaging Agent for Clinical Use

PURPOSE

Progress toward developing a novel radiocontrast agent for determining pO2 in tumors in a clinical setting is described. The imaging agent is designed for use with electron paramagnetic resonance imaging (EPRI), in which the collision of a paramagnetic probe molecule with molecular oxygen causes a spectroscopic change which can be calibrated to give the real oxygen concentration in the tumor tissue.

PROCEDURES

The imaging agent is based on a nanoscaffold of aluminum hydroxide (boehmite) with sizes from 100 to 200 nm, paramagnetic probe molecule, and encapsulation with a gas permeable, thin (10-20 nm) polymer layer to separate the imaging agent and body environment while still allowing O2 to interact with the paramagnetic probe. A specially designed deuterated Finland trityl (dFT) is covalently attached on the surface of the nanoparticle through 1,3-dipolar addition of the alkyne on the dFT with an azide on the surface of the nanoscaffold. This click-chemistry reaction affords 100% efficiency of the trityl attachment as followed by the complete disappearance of the azide peak in the infrared spectrum. The fully encapsulated, dFT-functionalized nanoparticle is referred to as RADI-Sense.

RESULTS

Side-by-side in vivo imaging comparisons made in a mouse model made between RADI-Sense and free paramagnetic probe (OX-071) showed oxygen sensitivity is retained and RADI-Sense can create 3D pO2 maps of solid tumors CONCLUSIONS: A novel encapsulated nanoparticle EPR imaging agent has been described which could be used in the future to bring EPR imaging for guidance of radiotherapy into clinical reality.

Recent Progress in Anti-Tumor Nanodrugs Based on Tumor Microenvironment Redox Regulation

The growth state of tumor cells is strictly affected by the specific abnormal redox status of the tumor microenvironment (TME). Moreover, redox reactions at the biological level are also central and fundamental to essential energy metabolism reactions in tumors. Accordingly, anti-tumor nanodrugs targeting the disruption of this abnormal redox homeostasis have become one of the hot spots in the field of nanodrugs research due to the effectiveness of TME modulation and anti-tumor efficiency mediated by redox interference. This review discusses the latest research results of nanodrugs in anti-tumor therapy, which regulate the levels of oxidants or reductants in TME through a variety of therapeutic strategies, ultimately breaking the original "stable" redox state of the TME and promoting tumor cell death. With the gradual deepening of study on the redox state of TME and the vigorous development of nanomaterials, it is expected that more anti-tumor nano drugs based on tumor redox microenvironment regulation will be designed and even applied clinically.

Drug-Loaded Polydopamine Nanoparticles for Chemo/Photothermal Therapy against Colorectal Cancer Cells

Colorectal cancer (CRC) is a common and deadly malignancy, ranking second in terms of mortality and third in terms of incidence on a global scale. The survival rates for CRC patients are unsatisfactory primarily because of the absence of highly effective clinical strategies. The efficacy of existing CRC treatments, such as chemotherapy (CT), is constrained by issues such as drug resistance and damage to healthy tissues. Alternative approaches such as photothermal therapy (PTT), while offering advantages over traditional therapies, suffer instead from a low efficiency in killing tumor cells when used alone. In this context, nanostructures can efficiently contribute to a selective and targeted treatment. Here, we combined CT and PTT by developing a nanoplatform based on polydopamine nanoparticles (PDNPs), selected for their biocompatibility, drug-carrying capabilities, and ability to produce heat upon exposure to near-infrared (NIR) irradiation. As a chemotherapy drug, sorafenib has been selected, a multikinase inhibitor already approved for clinical use. By encapsulating sorafenib in polydopamine nanoparticles (Sor-PDNPs), we were able to successfully improve the drug stability in physiological media and the consequent uptake by CRC cells, thereby increasing its therapeutic effects. Upon NIR stimulus, Sor-PDNPs can induce a temperature increment of about 10 °C, encompassing both PTT and triggering a localized and massive drug release. Sor-PDNPs were tested on healthy colon cells, showing minimal adverse outcomes; conversely, they demonstrated excellent efficacy against CRC cells, with a strong capability to hinder cancer cell proliferation and induce apoptosis. Obtained findings pave the way to new synergistic chemo-photothermal approaches, maximizing the therapeutic outcomes against CRC while minimizing side effects on healthy cells.

β-Glycosidase sensitive oral nanoparticles for combined photothermal and chemo treatment of colorectal cancer

Colorectal cancer is one of the most common malignant tumors in the world, and its treatment strategies mainly include surgical resection, chemotherapy, adjuvant radiotherapy, and immunotherapy. Among them, chemotherapy inevitably produces systemic toxicity due to the lack of tumor targeting properties and drug resistance caused by long-term medication frequently occurs, immensely constraining the efficacy of chemotherapy alone. To solve the above-mentioned problems, rhamnolipid was used to encapsulate the chemotherapeutic drug 5-FU and photothermal agent bismuthene nanosheets (BiNS), chitosan was applied as the shell of the nanoparticle, and BiNS@RHL-CS/5-FU NPs for oral administration was successfully prepared. When transported in the stomach and small intestine, the double protection of rhamnolipid and chitosan shell prevented the early release of BiNS and 5-FU. When transported to the colon, β-glycosidase existing in the microenvironment along with elevated pH degraded the chitosan shell, and the reduction in particle size was beneficial for tumor tissue to uptake nanoparticles, thus greatly improving the tumor targeting ability of 5-FU and reducing the systemic toxicity. Due to the presence of BiNS, 1.0 W cm-2 808 nm laser irradiation significantly increased the temperature of the tumor site, not only killing tumor cells directly but also promoting cell uptake and penetration of nanoparticles in the tumor tissue, accelerating the release of 5-FU and improving the sensitivity of tumor cells to chemotherapy, eventually solving the shortcomings of traditional chemotherapy alone. Excellent anti-tumor efficacy has been achieved in both in vitro and in vivo experiments.

Effect of Low Concentration of Nitroxides on SH-SY5Y Cells Transfected with the Tau Protein

Nitroxides, stable synthetic free radicals, are promising antioxidants, showing many beneficial effects both at the cellular level and in animal studies. However, the cells are usually treated with high millimolar concentrations of nitroxides which are not relevant to the concentrations that could be attained in vivo. This paper aimed to examine the effects of low (≤10 μM) concentrations of three nitroxides, 2,2,6,6-tetramethylpiperidin-1-oxyl (TEMPO), 4-hydroxy-TEMPO (TEMPOL) and 4-amino-TEMPO (TEMPAMINE), in pure chemical systems and on SH-SY5Y cells transfected with the human tau protein (TAU cells), a model of chronic cellular oxidative stress, and transfected with the empty plasmid (EP cells). All nitroxides were active in antioxidant-activity tests except for the 2,2'-azinobis-(3-ethylbenzthiazolin-6-sulfonate) radical (ABTS•) decolorization assay and reduced Fe3+, inhibited autoxidation of adrenalin and pyrogallol and oxidation of dihydrorhodamine123 by 3-morpholino-sydnonimine SIN-1. TEMPO protected against fluorescein bleaching from hypochlorite, but TEMPAMINE enhanced the bleaching. Nitroxides showed no cytotoxicity and were reduced by the cells to non-paramagnetic derivatives. They decreased the level of reactive oxygen species, depleted glutathione, and increased mitochondrial-membrane potential in both types of cells, and increased lipid peroxidation in TAU cells. These results demonstrate that even at low micromolar concentrations nitroxides can affect the cellular redox equilibrium and other biochemical parameters.

Design of Antioxidant Nanoparticle, which Selectively Locates and Scavenges Reactive Oxygen Species in the Gastrointestinal Tract, Increasing The Running Time of Mice

Excess reactive oxygen species (ROS) produced during strong or unfamiliar exercise cause exercise-induced gastrointestinal syndrome (EIGS), leading to poor health and decreased exercise performance. The application of conventional antioxidants can neither ameliorate EIGS nor improve exercise performance because of their rapid elimination and severe side effects on the mitochondria. Hence, a self-assembling nanoparticle-type antioxidant (RNPO ) that is selectively located in the gastrointestinal (GI) tract for an extended time after oral administration is developed. Interestingly, orally administered RNPO significantly enhances the running time until exhaustion in mice with increasing dosage, whereas conventional antioxidants (TEMPOL) tends to reduce the running time with increasing dosage. The running (control) and TEMPOL groups show severe damage in the GI tract and increased plasma lipopolysaccharide (LPS) levels after 80 min of running, resulting in fewer red blood cells (RBCs) and severe damage to the skeletal muscles and liver. However, the RNPO group is protected against GI tract damage and elevation of plasma LPS levels, similar to the nonrunning (sedentary) group, which prevents damage to the whole body, unlike in the control and TEMPOL groups. Based on these results, it is concluded that continuous scavenging of excessive intestinal ROS protects against gut damage and further improves exercise performance.

Efficacy of redox nanoparticles for improving survival of transplanted cells in a mouse model of ischemic stroke

The success of cell transplantation therapy for ischemic stroke is hindered by the low cell survival rate in poststroke brain, due in part to high free radical production and ensuing oxidative stress. We have developed redox nanoparticles to eliminate reactive oxygen species. In this study, we tested the protective efficacy of these redox nanoparticles in cell culture and a mouse model of ischemic stroke. Induced human dental pulp stem cells were subjected to oxygen-glucose deprivation and reoxygenation to recapitulate ischemia and reperfusion in the penumbra surrounding a cerebral infarct. Cell viability using WST-8 assay, apoptosis using TUNEL, free radicals using MitoSOX, and inflammatory cytokines using ELISA kit were measured in the presence and absence of redox nanoparticles after oxygen-glucose deprivation and reoxygenation. The scavenging activity of redox nanoparticles against reactive oxygen species was detected by electron spin resonance. Moreover, induced cells were transplanted intracerebrally into to the distal middle cerebral artery occlusion model with and without redox nanoparticles, and the survival rate measured. Cell viability was enhanced, while apoptosis, free radical generation, and inflammatory cytokine expression levels were reduced in cultures with redox nanoparticles. Further, reduced redox nanoparticles were detected in the cytoplasm, indicating free radical scavenging. Addition of redox nanoparticles also improved the survival rate of transplanted cells after 6 weeks in vivo. These redox nanoparticles may increase the applicability and success of induced stem cell therapy for ischemic stroke patents by promoting long-term survival.

A sequential delivery system based on MoS2 nanoflower doped chitosan/oxidized dextran hydrogels for colon cancer treatment

A sequential delivery system based on MoS₂ nanoflower (MoS₂ NF) doped chitosan (CS)/oxidized dextran (OD) hydrogels is developed for the treatment of colon cancer. 5-Fluorouracil (5-FU) is combined with polyethylenimine (PEI) decorated MoS₂ NF via electrostatic attraction and hydrogen bonding, and the obtained 5-FU/PEI/MoS₂ is encapsulated by 1-tetradecanol (TD), a commonly used phase transition material. The resultant TD/5-FU/PEI/MoS₂ (TFPM) is then co-encapsulated with methotrexate (MTX) in the CS/OD hydrogels generated via Schiff base reaction and electrostatic attraction. Because the electrostatic attraction between CS and OD is pH-sensitive, MTX and TD/5-FU/PEI/MoS₂ can be easily released from the hydrogels at pH 7.4. MoS₂ is an outstanding photothermal agent, and the generated hyperthermia under near infrared (NIR) irradiation can lead to the melting of TD and the consequent release of 5-FU encapsulated. More importantly, the generated hyperthermia under NIR irradiation can realize the chemo-photothermal synergistic tumor therapy. Finally, the practicability of the developed sequential delivery system is demonstrated by cytotoxicity test.

Design of a new self-assembling antioxidant nanomedicine to ameliorate oxidative stress in zebrafish embryos

Oxidative stress, which is a persistent state of elevated reactive oxygen species (ROS), is implicated in the pathogeneses of several diseases, making antioxidant-based therapeutics the aptest intervention. Nevertheless, the clinical failure of conventional low-molecular-weight (LMW) antioxidants in oxidative stress-related diseases to yield favorable therapeutic outcomes and an increased mortality rate attributable to their poor pharmacokinetic characteristics, necessitates the development of alternative therapeutics. In light of this, we designed and synthesized a new amphiphilic polymer functionalized with a clinically safe base polymer of poly(styrene-co-maleic anhydride) copolymer conjugated with the LMW pleiotropic antioxidant TEMPO (a potent antioxidant) and biocompatible poly(ethylene glycol) (TEMPO-installed PSMA-g-PEG), which self-assembles into nano-sized micelles (SMAPo^TN) under physiological conditions. We investigated its safety and antioxidant ability using zebrafish models. Common LMW antioxidants, such as 4-hydroxy-TEMPO (TEMPOL), vitamin C, N-acetyl-L-cysteine, and edaravone exposure induced phenotypic distortions, a manifestation of developmental toxicity, and resulted in high lethality in zebrafish larvae. LMW TEMPOL also adversely affected embryo hatchability, induced arrhythmia and cardiac edema, and failed to protect against oxidative stress. In contrast, exposure of zebrafish embryos to SMAPo^TN increased the hatchability, protected embryos against various inducers of oxidative stress, and did not induce any phenotypic alterations or discernible toxicity. Taken together, we conclude that SMAPo^TN surpasses LMW TEMPOL in terms of the ability to protect zebrafish, attributable to efficient ROS scavenging without perturbing normal redox homeostasis. These results imply that SMAPo^TN can be used as a therapeutic intervention against various oxidative stress-induced diseases. STATEMENT OF SIGNIFICANCE: Failure of low molecular weight (LMW) antioxidants to improve therapeutic index in various oxidative stress-related pathogenesis, attributable to their poor pharmacokinetic characteristics, greatly limits their clinical translation. To overcome this limitation, we developed a self-assembling antioxidant nanoparticle (SMAPo^TN) comprised of amphiphilic polymer; poly(styrene-co-maleic anhydride) conjugated with TEMPO as an antioxidant and biocompatible poly(ethylene glycol). Preliminary studies carried out in the in vivo models of zebrafish embryos confirmed that exposure of LMW antioxidant resulted in acute developmental toxicity, high lethality, and failure to rescue embryos against oxidative stress inducers. In contrast, SMAPo^TN did not exert discernible toxicity and significantly improved their survival under oxidative stress. Our finding establishes antioxidant nanoparticles as more suitable therapeutic intervention for oxidative stress-induced diseases than LMW antioxidants.

Probiotic Spore-Based Oral Drug Delivery System for Enhancing Pancreatic Cancer Chemotherapy by Gut-Pancreas-Axis-Guided Delivery

The chemotherapeutic effectiveness of pancreatic ductal adenocarcinoma (PDAC) is severely hampered by insufficient intratumoral delivery of antitumor drugs. Here, we demonstrate that enhanced pancreatic cancer chemotherapy can be achieved by probiotic spore-based oral drug delivery system via gut-pancreas axis translocation. Clostridium butyricum spores resistant to harsh external stress are extracted as drug carriers, which are further covalently conjugated with gemcitabine-loaded mesoporous silicon nanoparticles (MGEM). The spore-based oral drug delivery system (SPORE-MGEM) migrates upstream into pancreatic tumors from the gut, which increases intratumoral drug accumulation by ∼3-fold compared with MGEM. In two orthotopic PDAC mice models, tumor growth is markedly suppressed by SPORE-MGEM without obvious side effects. Leveraging the biological contact of the gut-pancreas axis, this probiotic spore-based oral drug delivery system reveals a new avenue for enhancing PDAC chemotherapy.

Microfluidized Dextran Microgels Loaded with Cisplatin/SPION Lipid Nanotherapeutics for Local Colon Cancer Treatment via Oral Administration

Multifunctional sequential targeted delivery system is developed as an efficient therapeutic strategy against malignant tumors with selective accumulation and minimal systemic drug absorption. The therapeutic system is comprised of microfluidized dextran microgels encapsulating cisplatin/superparamagnetic iron oxide nanoparticles (SPIONs)-loaded trilaurin-based lipid nanoparticles (LNPs). The microgel system is imparted hierarchically dual targeting via dextran and folic acid (FA) residues, leading to increases both in retention of the microgels in colon and in cellular uptake of the therapeutic LNPs by colon cancer cells while being used for oral therapeutic delivery. Encapsulation of the therapeutic LNPs into dextran microgels attained by microfluidized crosslinking reaction reduces gastrointestinal adhesion and prevents the FA-modified LNPs from cellular transport by proton-coupled FA transporters in small intestine during their oral delivery to colon. Upon enzymatic degradation of the dextran microgels by dextranase present exclusively in colon, LNPs thus released become more recognizable and readily internalized by FA receptor-overexpressing colon cancer cells. The combined chemo/magnetothermal therapeutic effect of dual targeted lipid nanoparticle-loaded microgels from entrapped lipidized cisplatin and alternating magnetic field-treated SPIONs significantly inhibits tumor growth and suppresses metastatic peritoneal carcinomatosis in orthotopic colon cancer-bearing mice.

Intestinal-targeted nanotubes-in-microgels composite carriers for capsaicin delivery and their effect for alleviation of Salmonella induced enteritis

Salmonella is a word-wide food-borne pathogen, which can cause severe enteritis and intestinal microbiota imbalance. Capsaicin (Cap), a food-based bioactive ingredient, has antibacterial and anti-inflammatory properties. However, its low solubility, low bioavailability and the irritation to digestive tract greatly limit its applications. Here, an intestinal responsively "nanotubes-in-microgel" composite carrier was constructed by capturing α-lactalbumin (α-lac) nanotubes in low-methoxy pectin microgels (LMP-NT) (52 μm). Cap was loaded in such system via hydrophobic interaction with a loading capacity of 38.02 mg/g. The LMP microgels remained stable and protected NT/Cap from early releasing in the gastric condition. It showed an excellent mucoadhesive capacity, which can prolong the intestinal retention up to 12 h and control release NT/Cap in intestine. Afterward, NT/Cap could penetrate across the mucus layer deeply and enter the intestinal villi epithelial cells efficiently. LMP-NT microgels achieved a mucoadhesive-to-penetrating transition in response to intestinal pH, improving the epithelium absorption and the in vivo bioavailability of Cap. Oral administration of LMP-NT/Cap could effectively alleviate enteritis caused by Salmonella infection and maintain the homeostasis of gut microbiota. Overall, this work suggested that LMP-NT composite microgels were promising for intestine-targeted and oral delivery of hydrophobic bioactive food compounds.

Orally administrable polyphenol-based nanoparticles achieve anti-inflammation and antitumor treatment of colon diseases

Colorectal cancer is the third most common malignancy that leads to significant mortality around the world. Chronic colonic inflammation could induce a protumor effect by the massive release of pro-inflammatory cytokines, facilitating migration, invasion, and metastasis of malignant cells in colorectal cancer. Therefore, developing a combination regimen of anti-inflammation and antitumor therapies is a promising strategy for the treatment of colorectal cancer. Here, we report that tannic acid-containing nanoparticles, formed by a turbulent-mixing technique, have exhibited uniform size, high stability, and pH-triggered drug release in the gastrointestinal tract, and could overcome intestinal mucosa for drug delivery in the colorectal region. As a drug carrier itself, with potent antioxidant and anti-inflammatory properties, tannic acid-containing nanoparticles showed great therapeutic effect in preventing the development of colitis-associated colorectal cancer (CAC) through oral administration. Furthermore, we used a therapeutic nanocarrier to deliver chemotherapeutic drugs for CAC treatment, generating lower systemic toxicity and superior antitumor performance through concurrent anti-inflammation and antitumor treatment. As a result, we confirmed that the drug carrier itself with therapeutic function could improve the overall therapeutic performance, and provided a safe and effective tannic acid-containing nanoplatform for the prevention and treatment of colon diseases.

Zn-dipicolylamine-based reactive oxygen species-responsive lipids for siRNA delivery and in vivo colitis treatment

The reduction of ROS and inflammatory factor levels plays important role in the treatment of colitis. A series of ROS-responsive lipids (ZnDPA-R) based on the thioketal structure were designed and synthesized. It was hoped that the lipidic materials could combine ROS consumption and siRNA delivery capacity to achieve synergistic treatment of colitis. The target liposomes could combine with the phosphate backbone of siRNA to form lipoplexes with the size of ∼100 nm, and could deliver siRNA cargo into the cell. The results of in vitro anti-inflammatory experiments showed that the lipids may effectively consume ROS in cells. Meanwhile, the lipoplexes significantly reduced the expression levels of TNF-α mRNA and related inflammatory factors in macrophages. After PEGylation, the lipoplex was used for the treatment of mouse colitis, and biodistribution results proved that the lipoplexes effectively aggregated in the intestine. The delivery system could not only response to the high ROS level at colitis via thioketal breaking, but also could assist in the treatment of inflammation by ROS consumption. The treatment results revealed that the levels of TNF-α mRNA and related inflammatory factors at the colon lesion were largely reduced, and the inflammatory symptoms were significantly relieved. Hematology test results indicated that the treatment was safe and induced no obvious side effects on mice. This study may shed light on the synergistic treatment for colitis via anti-inflammatory siRNA delivery and ROS depletion strategies. STATEMENT OF SIGNIFICANCE: Downregulation of inflammatory factors and reactive oxygen species (ROS) levels is critical in treating colitis. In the present study, a series of ROS-responsive lipid molecules based on the Zn-DPA headgroup and thioketal linkage were synthesized for delivering TNF-α siRNA and for treating colitis. In addition to silencing the expression of TNF-α mRNA and the related inflammatory factors, the material also achieved synergistic treatment by simultaneous consumption of ROS in the colon lesion. In vitro cell experiments and in vivo colitis treatment in mice showed that the lipoplex exerted a satisfactory therapeutic effect on colitis, and the symptoms of colitis in mice were significantly alleviated. The present study may shed light on the synergistic treatment for colitis through anti-inflammatory siRNA delivery and ROS depletion strategies.

A silica-based antioxidant nanoparticle for oral delivery of Camptothecin which reduces intestinal side effects while improving drug efficacy for colon cancer treatment

Camptothecin (CPT) is a potent anticancer agent for the treatment of colorectal cancer; however, it exhibits some limitations, including poor solubility, low stability, and low bioavailability via oral administration, which restrict its usability in clinical treatments. In addition, overproduction of reactive oxygen species (ROS) during chemotherapy induces drug resistance and severe intestinal side effects. In this study, silica-installed ROS scavenging nanoparticles (siRNP) with 50-60 nm in diameter were employed to overcome the aforementioned drawbacks of CPT. The solubility of CPT was significantly improved by incorporating it into the core of the nanoparticle, forming CPT-loaded siRNP (CPT@siRNP). The anticancer activity of CPT@siRNP against colorectal cancer cells (C-26) in vitro was significantly improved as compared to free CPT through higher efficiency of intracellular internalization and induction of apoptosis. Owing to its antioxidant properties, CPT@siRNP reduced cytotoxicity to normal endothelial cells, which was in sharp contrast to the high toxicity of free CPT. Oral administration of CPT and CPT@siRNP to the C-26 tumor-bearing mice exhibited antitumor activity, accompanied by effective suppression of tumor growth. Although CPT treatment suppressed tumor progression, it caused severe side effects, including intestinal damage and significant bodyweight loss. Interestingly, such noticeable side effects were not observed in the mice treated with CPT@siRNP, and the effect of tumor growth inhibition tended to be similar to or higher than that of CPT treatment. The results obtained in this study indicate that CPT@siRNP is a potential therapeutic nanomedicine for the treatment of colon cancer. STATEMENT OF SIGNIFICANCE: Here we employed silica-containing antioxidant nanoparticle (siRNP) as promising oral delivery nanocarrier of campothecin (CPT) to treat colon cancer. The design of siRNP via covalent conjugation of antioxidant nitroxide radicals and the silanol groups in the polymer backbone contributes to a significant increase in the absorption of hydrophobic drug molecules inside the core and enhances the stability of nanoparticles in the gastrointestinal environment for oral drug delivery. CPT-loaded siRNP (CPT@siRNP) significantly improved solubility of CPT. As compared to free CTP, the CPT@siRNP treatment showed a significantly higher toxicity to colon cancer cell, inhibition of cancer cell migration, and induction of apopotosis. With the antioxidant feature, siRNP also significantly suppressed the intestinal side effects caused by CPT treatment in tumor-bearing mouse model.

All-in-one theranostic nano-platform based on polymer nanoparticles for BRET/FRET-initiated bioluminescence imaging and synergistically anti-inflammatory therapy for ulcerative colitis

Background

Ulcerative colitis (UC), a subtype of inflammatory bowel disease (IBD), has evolved into a global burden given its high incidence. There is a clinical need to create better diagnostic and therapeutic approaches to UC.

Results

We fabricated P-selectin binding peptide-decorated poly lactic-co-glycolic acid (PBP-PLGA-NP) doped with two lipophilic dyes, DiL and DiD. Meanwhile, two low-toxic anti-inflammatory natural products (betulinic acid [BA] and resveratrol [Res]) were co-loaded in the PBP-PLGA-NP system. The BA/Res-loaded NPs had an average size of around 164.18 nm with a negative zeta potential (− 25.46 mV). Entrapment efficiencies of BA and Res were 74.54% and 52.33%, respectively, and presented a sustained drug release profile. Further, the resulting PBP-PLGA-NP could be internalized by RAW 264.7 cells and Colon-26 cells efficiently in vitro and preferentially localized to the inflamed colon. When intravenously injected with luminol, MPO-dependent bioluminescence imaging to visualize tissue inflammation was activated by the bioluminescence and fluorescence resonance energy transfer (BRET-FRET) effect. Importantly, injected NPs could remarkably alleviate UC symptoms yet maintain intestinal microbiota homeostasis without inducing organ injuries in the mice models of colitis.

Conclusions

This theranostic nano-platform not only serves as a therapeutic system for UC but also as a non-invasive and highly-sensitive approach for accurately visualizing inflammation.

Graphical Abstract

Supplementary Information

The online version contains supplementary material available at 10.1186/s12951-022-01299-8.

Nanodiamond-based multifunctional platform for oral chemo-photothermal combinational therapy of orthotopic colon cancer

Combination therapy system has become a promising strategy for achieving favorable antitumor efficacy. Herein, a novel oral drug delivery system with colon localization and tumor targeting functions was designed for orthotopic colon cancer chemotherapy and photothermal combinational therapy. The polydopamine coated nanodiamond (PND) was used as the photothermal carrier, through the coupling of sulfhydryl-polyethylene glycol-folate (SH-PEG-FA) on the surface of PND to achieve systematic colon tumor targeting, curcumin (CUR) was loaded as the model drug, and then coated with chitosan (CS) to achieve the long gastrointestinal tract retention and colon localization functions to obtain PND-PEG-FA/CUR@CS nanoparticles. It has high photothermal conversion efficiency and good photothermal stability and exhibited near-infrared (NIR) laser-responsive drug release behavior. Folate (FA) modification effectively promotes the intracellular uptake of nanoparticles by CT26 cells, and the combination of chemotherapy and photothermal therapy (CT/PTT) can enhance cytotoxicity. Compared with free CUR group, nanoparticles prolonged the gastrointestinal tract retention time, accumulated more in colon tumor tissues, and exhibited good photothermal effect in vivo. More importantly, the CT/PTT group exhibited satisfactory tumor growth inhibition effects with good biocompatibility in vivo. In summary, this oral drug delivery system is an efficient platform for chemotherapy and photothermal combinational therapy of orthotopic colon cancer.

Development of nanotechnology-mediated precision radiotherapy for anti-metastasis and radioprotection

Radiotherapy (RT), including external beam RT and internal radiation therapy, uses high-energy ionizing radiation to kill tumor cells.

SHARP hydrogel for the treatment of inflammatory bowel disease

Inflammatory bowel disease (IBD) is a relapsing and remitting inflammatory disease affecting millions of people worldwide. The active phase of IBD is characterized by excessive formation of reactive oxygen species (ROS) in the intestinal mucosa, which further accelerates the inflammatory process. A feasible strategy for the IBD treatment is thus breaking the oxidation-inflammation vicious circle by scavenging excessive ROS with the use of a suitable antioxidant. Herein, we have developed a novel hydrogel system for oral administration utilizing sterically hindered amine-based redox polymer (SHARP) incorporating covalently bound antioxidant SHA groups. SHARP was prepared via free-radical polymerization by covalent crosslinking of 2-hydroxyethyl methacrylate (HEMA), poly(ethylene oxide) methyl ether methacrylate (PEGMA) and a SHA-based monomer, N-(2,2,6,6-tetramethyl-piperidin-4-yl)-methacrylamide. The SHARP hydrogel was resistant to hydrolysis and swelled considerably (∼90% water content) under the simulated gastrointestinal tract (GIT) conditions, and exhibited concentration-dependent antioxidant properties in vitro against different ROS. Further, the SHARP hydrogel was found to be non-genotoxic, non-cytotoxic, non-irritating, and non-absorbable from the gastrointestinal tract. Most importantly, SHARP hydrogel exhibited a statistically significant, dose-dependent therapeutic effect in the mice model of dextran sodium sulfate (DSS)-induced acute colitis. Altogether, the obtained results suggest that the SHARP hydrogel strategy holds a great promise with respect to IBD treatment.

Nanozymes Regulate Redox Homeostasis in ROS-Related Inflammation

Reactive oxygen species (ROS), in moderate amounts, play an essential role in regulating different physiological functions in organisms. However, increased amounts of ROS may cause oxidative stress and damage to biomolecules, leading to a variety of diseases including inflammation and even cancer. Therefore, ROS scavenging reagents are needed to maintain healthy levels of ROS. With considerable advances in nanotechnology, nanozymes possess SOD or CAT-like activities with outstanding free radical scavenging activity, facile synthesis conditions, and excellent biocompatibility. Based on these extraordinary properties, nanozymes has been used to modulate the redox homeostasis and relieve the ROS-related injury. This has led to the emergence of nanozyme-based therapies. In the current review, we presented recently developed applications of nanozymes to treat ROS-dependent disorders with an emphasis on inflammatory and brain diseases.

'Green' nanotherapeutics from tea leaves for orally targeted prevention and alleviation of colon diseases

Although synthesized nanotherapeutics (NTs) are attractive for the oral treatment of colon diseases, their clinical translations are constrained by the unsatisfactory therapeutic outcomes, potential adverse effects, and high cost of mass production. Here, we report the development of tea leaf-derived natural NTs with desirable particle sizes (140.0 nm) and negative surface charge (-14.6 mV). These natural exosome-like NTs were found to contain large amounts of lipids, some functional proteins, and many bioactive small molecules. Specifically, galactose groups on the surface of NTs could mediate their specific internalization by macrophages via galactose receptor-mediated endocytosis. Moreover, these NTs were able to reduce the production of reactive oxygen species, inhibit the expression of pro-inflammatory cytokines, and increase the amount of anti-inflammatory IL-10 secreted by macrophages. Orally administered NTs could efficiently inhibit the inflammatory bowel responses, restore disrupted colonic barriers and enhance the diversity and overall abundance of gut microbiota, thereby preventing or alleviating inflammatory bowel disease and colitis-associated colon cancer. The present study brings new insights to the facile application of a versatile and robust natural nanoplatform for the prevention and treatment of colon diseases.

Orally Administrable Therapeutic Nanoparticles for the Treatment of Colorectal Cancer

Colorectal cancer (CRC) is one of the most common and lethal human malignancies worldwide; however, the therapeutic outcomes in the clinic still are unsatisfactory due to the lack of effective and safe therapeutic regimens. Orally administrable and CRC-targetable drug delivery is an attractive approach for CRC therapy as it improves the efficacy by local drug delivery and reduces systemic toxicity. Currently, chemotherapy remains the mainstay modality for CRC therapy; however, most of chemo drugs have low water solubility and are unstable in the gastrointestinal tract (GIT), poor intestinal permeability, and are susceptible to P-glycoprotein (P-gp) efflux, resulting in limited therapeutic outcomes. Orally administrable nanoformulations hold the great potential for improving the bioavailability of poorly permeable and poorly soluble therapeutics, but there are still limitations associated with these regimes. This review focuses on the barriers for oral drug delivery and various oral therapeutic nanoparticles for the management of CRC.

Antioxidant Nanomedicine Significantly Enhances the Survival Benefit of Radiation Cancer Therapy by Mitigating Oxidative Stress-Induced Side Effects

Oxidative stress-induced off-target effects limit the therapeutic window of radiation therapy. Although many antioxidants have been evaluated as radioprotective agents, none of them are in widespread clinical use, owing to the side effects of the antioxidants themselves and the lack of apparent benefit. Aiming for a truly effective radioprotective agent in radiation cancer therapy, the performance of a self-assembling antioxidant nanoparticle (herein denoted as redox nanoparticle; RNP) is evaluated in the local irradiation of a subcutaneous tumor-bearing mouse model. Since RNP is covered with a biocompatible shell layer and possesses a core-shell type structure of several tens of nanometers in size, its lifetime in the systemic circulation is prolonged. Moreover, since 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO), one of the most potent antioxidants, is covalently encapsulated in the core of RNP, it exerts intense antioxidant activity and induces fewer adverse effects by avoiding leakage of the TEMPO molecules. Preadministration of RNP to the mouse model effectively mitigates side effects in normal tissues and significantly extends the survival benefit of radiation cancer therapy. Moreover, RNP pretreatment noticeably increases the apoptosis/necrosis ratio of radiation-induced cell death, a highly desirable property to reduce the chronic side effects of ionizing irradiation.

Cerium oxide nanoparticles acts as a novel therapeutic agent for ulcerative colitis through anti-oxidative mechanism

BACKGROUND

Cerium (IV) oxide (CeO₂) exhibit anti-inflammatory activity via scavenge free radicals and decreasing the oxygen species (ROS) production. Here we aimed to exhibit the therapeutic effect of this nanoparticle in experimental colitis models.

METHODS

Cerium oxide nanoparticles (CeONPs) were synthesized via using UiO-66 as a precursor. We used dextran sodium sulfate (DSS) to induce colitis in experimental models to investigate the anti-inflammatory effect of CeONPs. Colitis models are divided into four groups to receive the treatment, including control, colitis, cerium oxide, and sulfasalazine. We evaluated the therapeutic effects of CeONPs for the increased colitis clinical symptoms and attenuated the histological damage to colon tissue in colitis.

RESULT

This nanoparticle was significantly able to reduce the clinical symptoms of colitis. Moreover, CeONPs can enhance the disease activity index such as body lose weight, diarrhea, rectal bleeding, colon length, and spleen weight. Moreover, CeONPs showed a significant reduction in the histological characteristics of the colitis models.

CONCLUSION

These results suggest that CeONPs can be considered as promising therapeutic agents in treating the ulcerative colitis.

Therapeutic effect of an anti-tuberculosis agent, isoniazid, and its nano-isoform in ulcerative colitis

BACKGROUND

Isoniazid (INH) is well known as a first-line anti-tuberculosis, while some studies demonstrate that it has anti-inflammatory activity via a different mechanism such as inhibitionthe production of IL-1, ROS, activation of PPARγ expression, inhibition of the transcriptional regulatory activity of NF-κB and AP-1. The aim of this study, investigate the anti-inflammatory effect of INH and INH combined with Sulfasalazine-loaded nanoparticles (NPs) in the ulcerative colitis mouse model.

METHODS

To investigate the anti-inflammatory effect of INH and NPs in the ulcerative colitis mice model, we evaluated the effect of INH clinical symptoms and colonic mucosal histology in colitis.

RESULT

The present study demonstrates that combination therapy of INH with sulfasalazine as well as NPs reduces the symptom of ulcerative colitis and improved disease activity index include body lose weight, diarrhea, rectal bleeding, colonic length, spleen weight, and colon histopathological score in DSS-induced colitis mice model.

CONCLUSION

Our results suggest that the nanoforms of INH with sulfasalazine enhances the therapeutic effect of the drugs in the treatment of ulcerative colitis.

Oral delivery of antioxidant enzymes for effective treatment of inflammatory disease

Oral administration of protein is very challenging for therapeutic applications due to its instability and easy degradation in the gastrointestinal tract. Herein, we reported an approach to encapsulate native anti-inflammatory proteins in wind chimes like cyclodextrin (WCC) for efficient oral protein delivery. The amphiphilic WCC can self-assemble into nanoparticles in aqueous solution and achieve superior encapsulation of two antioxidant enzymes such as superoxide dismutase (SOD) and catalase (CAT) by simply mixing with protein solution, avoiding any extra cumbersome steps that might inactivate protein. WCC nanovehicles can effectively protect enzyme activity and enhance their intracellular delivery. SOD and CAT co-loaded WCC nanoparticles (SC/WCC) can integrate the synergistic effect of SOD and CAT for enhancing the removal of reactive oxygen species (ROS), effectively inhibit the inflammatory response by reducing the secretion of proinflammatory factors and protect cells from ROS-induced oxidative damage. In the mouse colitis model, SC/WCC administered orally was able to efficiently accumulate in the inflamed colon, significantly inhibited the expression of proinflammatory mediators and notably alleviated the symptoms related to colitis. Therefore, we believe that the strategies we described here may provide a convenient and powerful platform for the treatment of other inflammatory diseases.

Newly Developed Self-Assembling Antioxidants as Potential Therapeutics for the Cancers

Elevated reactive oxygen species (ROS) have been implicated as significant for cancer survival by functioning as oncogene activators and secondary messengers. Hence, the attenuation of ROS-signaling pathways in cancer by antioxidants seems a suitable therapeutic regime for targeting cancers. Low molecular weight (LMW) antioxidants such as 2,2,6,6-tetramethylpyperidine-1-oxyl (TEMPO), although they are catalytically effective in vitro, exerts off-target effects in vivo due to their size, thus, limiting their clinical use. Here, we discuss the superior impacts of our TEMPO radical-conjugated self-assembling antioxidant nanoparticle (RNP) compared to the LMW counterpart in terms of pharmacokinetics, therapeutic effect, and adverse effects in various cancer models.

Regulation of Hedgehog Signaling by miRNAs and Nanoformulations: A Possible Therapeutic Solution for Colorectal Cancer

Hedgehog (Hh) signaling aberrations trigger differentiation and proliferation in colorectal cancer (CRC). However, the current approaches which inhibit this vital cellular pathway provoke some side effects. Therefore, it is necessary to look for new therapeutic options. MicroRNAs are small molecules that modulate expression of the target genes and can be utilized as a potential therapeutic option for CRC. On the other hand, nanoformulations have been implemented in the treatment of plethora of diseases. Owing to their excessive bioavailability, limited cytotoxicity and high specificity, nanoparticles may be considered as an alternative drug delivery platform for the Hh signaling mediated CRC. This article reviews the Hh signaling and its involvement in CRC with focus on miRNAs, nanoformulations as potential diagnostic/prognostic and therapeutics for CRC.

Management of tumor growth and angiogenesis in triple-negative breast cancer by using redox nanoparticles

In cancer, angiogenesis is a critical phenomenon of nascent blood vessel development to facilitate the oxygen and nutrient supply prerequisite for tumor progression. Therefore, targeting tumors at the angiogenesis step may be significant to prevent their advanced progression and metastasis. Although angiogenesis inhibitors can limit the further growth of tumors, complete eradication of tumors may not be possible by monotherapy alone. Therefore, a therapeutic regimen targeting both tumor growth and its vasculature is essential. Because reactive oxygen species (ROS) are fundamental to both angiogenesis and tumor growth, the use of antioxidants may be an effective dual approach to inhibit tumors. We previously confirmed that our original antioxidant nitroxide radical-containing nanoparticles (RNPs) such as pH-sensitive RNP^N_, and pH-insensitive RNP^O, effectively attenuates the tumorigenic and metastasis potentials of triple-negative breast cancer. In this study, we further investigated the efficacy of RNPs to limit the tumor progression by inhibiting the ROS-regulated cancer angiogenesis in a triple-negative breast cancer model. Here, we confirmed that RNPs significantly inhibited in vitro angiogenesis, attributed to the downregulation of the ROS-regulated angiogenesis inducer, vascular endothelial growth factor (VEGF) in the breast cancer cell line (MDA-MB231) and human umbilical vein endothelial cells (HUVEC), which was consistent with decreased cellular ROS. TEMPOL, a low-molecular-weight (LMW) control antioxidant, exhibited anti-angiogenic effects accompanied by cytotoxicity to the endothelial cells. In an in vivo xenograft model for breast cancer, RNPs exerted significant anti-tumor effect due to the decreased expression of tumor VEGF, which prevented accumulation of the endothelial cells. It should be noted that such efficacy of RNPs was obtained with negligible off-target effects. On the other hand, TEMPOL, because of its size, exerted anti-angiogenesis effect accompanied with injuries to the kidneys, which corroborated with previous reports. Our findings imply that RNPs are more potential antioxidants than their LMW counterparts, such as TEMPOL, for the management of breast cancers.

Fibrinolytic tissue plasminogen activator installed redox-active nanoparticles (t-PA@iRNP) for cancer therapy

Favorable blood flow within solid tumors has become the principal strategy for drug delivery. The use of thrombolytic drugs, such as tissue plasminogen activator (t-PA), in combination with other drugs or drug carriers may increase their therapeutic effect by increasing drug delivery near the solid tumor through fibrin degradation and blood flow restoration. We, therefore, designed t-PA-installed redox-active nanoparticles (t-PA@iRNP) to improve the perfusion of antioxidant nanoparticles in tumors, via fibrin degradation to decompress tumor vessels. Additionally, antioxidant iRNP was developed for tumor inhibition by reduction of critically elevated levels of reactive oxygen species (ROS) in tumors. The t-PA@iRNP, when administered to a colon cancer model, degraded the deposited fibrin and improved the iRNP and immune cells penetration in tumor tissues via the restored blood flow, thus more effectively inhibited tumor growth. The anti-tumor effect of iRNP was attributed to ROS-reduction mediated downregulation of crucial a transcriptional factor, NF-κB. Conclusively, this study provides a new strategy to enhance the delivery of nanotherapeutics into solid tumors.

Anlar G, A. Hussein E, Elzatahry A, C. Yalcin H. Effect of Flow-Induced Shear Stress in Nanomaterial Uptake by Cells: Focus on Targeted Anti-Cancer Therapy

Recently, nanomedicines have gained a great deal of attention in diverse biomedical applications, including anti-cancer therapy. Being different from normal tissue, the biophysical microenvironment of tumor cells and cancer cell mechanics should be considered for the development of nanostructures as anti-cancer agents. Throughout the last decades, many efforts devoted to investigating the distinct cancer environment and understanding the interactions between tumor cells and have been applied bio-nanomaterials. This review highlights the microenvironment of cancer cells and how it is different from that of healthy tissue. We gave special emphasis to the physiological shear stresses existing in the cancerous surroundings, since these stresses have a profound effect on cancer cell/nanoparticle interaction. Finally, this study reviews relevant examples of investigations aimed at clarifying the cellular nanoparticle uptake behavior under both static and dynamic conditions.

Redox injectable gel protects osteoblastic function against oxidative stress and suppresses alveolar bone loss in a rat peri-implantitis model

Dental implant surgery is a routine treatment in clinical dentistry. However, implant surgery is associated with an increased risk of bacterially induced peri-implantitis and the production of reactive oxygen species (ROS), with no established treatment. We recently designed a new redox injectable gel (RIG) containing nitroxide radicals for the treatment of peri-implantitis. Here, we investigated the antioxidative effect of RIG as a preventive therapy for ROS-associated peri-implantitis in a rat model of alveolar bone resorption and in vitro. In each rat, the maxillary first molar tooth was replaced with a screw-type implant, and rats were assigned to one of four groups: an implant alone, an implant with infection, implant with infection and treatment with nRIG (a non-nitroxide radical-containing injectable hydrogel) or RIG. We confirmed the long-term retention of RIG in the peri-implant region and found that RIG significantly protected the alveolar bone volume and decreased lipid peroxidation. In culture, we found that RIG restored osteoblast proliferation and differentiation in the presence of hydrogen peroxide (H₂O₂)-induced oxidative stress. Moreover, using a malondialdehyde assay of lipid peroxidation, we found that RIG suppressed oxidative stress in H₂O₂-treated rat osteoblasts. Overall, RIG is anticipated as a prophylactic treatment for peri-implantitis and may help preserve oral function. Statement of Significance 1. Implant surgery is associated with an increased risk of bacterially induced peri-implantitis and the production of reactive oxygen species (ROS). We designed a novel redox injectable gel (RIG) containing nitroxide radicals for the treatment of peri-implantitis. In this study, we investigated the antioxidative effect of RIG as a preventive therapy for ROS-associated peri-implantitis in a rat model and in vitro. 2. We showed that treatment with RIG reduces oxidative damage in a rat peri-implantitis model, protecting against bone resorption and a loss of bone density. We showed that RIG inhibits H₂O₂-mediated decreases in proliferation, osteoblast differentiation, and mineralization, and also against lipid peroxidation in vitro. Our results indicate that RIG has an antioxidative effect of peri-implantitis.

Self-assembled polydopamine nanoparticles improve treatment in Parkinson's disease model mice and suppress dopamine-induced dyskinesia

Although Levodopa (l-DOPA), a dopamine precursor, exhibits a high risk of dyskinesia, it remains the primary treatment in Parkinson's disease (PD), a progressive neurodegenerative disorder. In this study, we designed poly(l-DOPA)-based self-assembled nanodrug (Nano^DOPA) from amphiphilic block copolymer possessing poly(l-DOPA(OAc)₂), which is a precursor of l-DOPA as a hydrophobic segment, for treatment in a PD model mouse. Under physiological enzyme treatment, the poly(l-DOPA(OAc)₂) in the block copolymer was hydrolyzed to liberate l-DOPA gradually. Using the MPTP-induced PD mouse model, we observed that mice treated with Nano^DOPA demonstrated a significant improvement of PD symptoms compared to the l-DOPA treatment. Interestingly, the Nano^DOPA treatment did not cause the dyskinesia symptoms, which was clearly observed in the l-DOPA-treated mice. Furthermore, Nano^DOPA exhibited remarkably lower toxicity in vitro compared to l-DOPA, in addition with no noticeable Nano^DOPA toxicity observed in the treated mice. These results suggested that self-assembled Nano^DOPA is a promising therapeutic in the treatment of PD. STATEMENT OF SIGNIFICANCE: In this study, we proposed a therapeutic approach for the effective treatment of Parkinson's disease (PD) using newly designed poly(l-DOPA)-based self-assembled nanodrug (Nano^DOPA) prepared from amphiphilic block copolymers possessing poly(l-DOPA(OAc)₂), which is a precursor of l-DOPA as a hydrophobic segment, for treatment in a PD model mouse. Under physiological enzyme treatments, Nano^DOPA was hydrolyzed to liberate l-DOPA gradually, improving the pharmacokinetic value of l-DOPA. The mice treated with Nano^DOPA significantly improved PD symptoms compared to the l-DOPA treatment in a neurotoxin-induced PD mouse model. Interestingly, Nano^DOPA treatment did not cause dyskinesia symptoms, which was observed in the l-DOPA-treated mice. The obtained results in this study suggested that self-assembled Nano^DOPA is a promising therapeutic in the treatment of PD.

Ultrasmall Rhodium Nanozyme with RONS Scavenging and Photothermal Activities for Anti-Inflammation and Antitumor Theranostics of Colon Diseases

Colitis-associated colorectal cancer (CAC), in which chronic inflammation is a well-recognized carcinogen, requires concurrent anti-inflammation and antitumor treatments in the clinic. Herein, we report polyethylene glycol (PEG)-coated (PEGylated) ultrasmall rhodium nanodots (Rh-PEG NDs) can serve as a metallic nanozyme with reactive oxygen and nitrogen species (RONS) scavenging properties as well as photothermal activities for anti-inflammation and antitumor theranostics in colon diseases. Benefiting from multienzyme activities against RONS, Rh-PEG NDs can decrease the levels of pro-inflammatory cytokines (TNF-α, IL-6), resulting in good anti-inflammatory effect on dextran sulfate sodium-induced colitis. By virtue of high photothermal conversion efficiency (48.9%), Rh-PEG NDs demonstrate complete ablation of CT-26 colon tumor without any recurrence. Most importantly, Rh-PEG NDs exhibit good biocompatibility both at the cellular and animal levels. Our findings provide a paradigm to utilize metallic nanozymes for the potential management of colon diseases.

Oral Targeted Delivery by Nanoparticles Enhances Efficacy of an Hsp90 Inhibitor by Reducing Systemic Exposure in Murine Models of Colitis and Colitis-Associated Cancer

BACKGROUND AND AIMS

Heat shock protein 90 [Hsp90]-targeted therapy has been proposed as a promising strategy for the treatment of ulcerative colitis [UC] and colitis-associated cancer [CAC]. Systemic administration of the Hsp90 inhibitor, 17-AAG, was found to be profoundly protective in preclinical mouse models of inflammatory bowel disease [IBD]. However, the therapeutic potential of 17-AAG is limited by potential side effects associated with its systemic exposure and the modest bioavailability afforded by its oral administration.

METHODS

To address these issues, we used a versatile single-step surface-functionalizing technique to prepare a 17-AAG oral delivery system using PLGA/PLA-PEG-FA nanoparticles [NP-PEG-FA/17-AAG].

RESULTS

NP-PEG-FA could be efficiently taken up by mouse Colon-26 cells and activated Raw 264.7 cells in vitro and by inflamed mouse colitis tissues in vivo. The therapeutic efficacy of orally administrated NP-PEG-FA/17-AAG was evaluated in in vivo models using dextran sulphate sodium [DSS]-induced UC and azoxymethane [AOM]/DSS-induced CAC, and the results indicated that NP-PEG-FA/17-AAG significantly alleviated the symptoms of UC and CAC. More importantly, our inflamed colitis-targeted 17-AAG nano-formulation reduced systemic exposure and provided a degree of therapeutic response similar to that obtained by systemic administration [intraperitoneal] of 17-AAG, but at a ten-fold lower dose.

CONCLUSIONS

We describe a convenient, orally administrated 17-AAG delivery system that exhibits enhanced efficacy in UC and CAC therapy while reducing systemic exposure. This system may represent a promising therapeutic approach for treating UC and CAC.

A Multifunctional Nanotherapy for Targeted Treatment of Colon Cancer by Simultaneously Regulating Tumor Microenvironment

Colitis-associated colon cancer (CAC) is a widely recognized cancer, while treatment with the existing chemotherapeutic drugs affords limited clinical benefits. Herein we proposed a site-specific, combination nanotherapy strategy for targeted treatment of CAC by the oral route. Methods: A reactive oxygen species (ROS)-responsive and hydrogen peroxide-eliminating material OCD was synthesized, which was further produced into a functional nanoparticle (OCD NP). The antioxidative stress and anti-inflammatory effects of OCD NP were examined by in vitro and in vivo experiments. By packaging an anticancer drug camptothecin-11 (CPT-11) into OCD NP, a ROS-responsive nanotherapy CPT-11/OCD NP was obtained, and its antitumor activity was evaluated by both in vitro and in vivo studies. Preliminary safety studies were also performed for CPT-11/OCD NP in mice. Results: OCD NP significantly attenuated oxidative stress and inhibited inflammatory response in different cells and mice with induced colitis. CPT-11/OCD NP could selectively release drug molecules under intestinal pH conditions and at high levels of ROS. In C26 murine colon carcinoma cells, this nanotherapy showed significantly higher antitumor activity compared to free CPT-11 and a non-responsive CPT-11 nanotherapy. Correspondingly, oral delivery of CPT-11/OCD NP notably inhibited tumorigenesis and tumor growth in mice with induced CAC. By combination therapy with the nanovehicle OCD NP in the inflammatory phase, more desirable therapeutic effects were achieved. Furthermore, CPT-11/OCD NP displayed excellent safety profile for oral administration at a dose that is 87.3-fold higher than that employed in therapeutic studies. Conclusions: Anticancer nanotherapies derived from intrinsic anti-inflammatory nanocarriers are promising for targeted combination treatment of inflammation-associated tumors by simultaneously shaping pro-inflammatory microenvironment toward a relatively normal niche sensitive to chemotherapy.

Redox Nano-Architectures: Perspectives and Implications in Diagnosis and Treatment of Human Diseases

SIGNIFICANCE

Efficient targeted therapy with minimal side-effects is the need of the hour. Locally altered redox state is observed in several human ailments, such as inflammation, sepsis, and cancer. This has been taken advantage of in designing redox-responsive nanodrug carriers. Redox-responsive nanosystems open a door to a multitude of possibilities for the control of diseases over other drug delivery systems. Recent Advances: The first-generation nanotherapy relies on novel properties of nanomaterials to shield the drug and deliver it to the diseased tissue or organ. The second generation is based on targeting the drug or diagnostic material to the diseased cell-specific receptors, or to a particular organ to improve the efficacy of the drug. The third and the latest generation of nanocarriers, the stimuli-responsive nanocarriers exploit the disease condition or environment to specifically deliver the drug or diagnostic probe for the best diagnosis and treatment. Several different kinds of stimuli such as temperature, magnetic field, pH, and altered redox state-responsive nanosystems have educed immense promise in the field of nanomedicine and therapy.

CRITICAL ISSUES

We describe the evolution of nanomaterial since its inception with an emphasis on stimuli-responsive nanocarriers, especially redox-sensitive nanocarriers. Importantly, we discuss the future perspectives of redox-responsive nanocarriers and their implications.

FUTURE DIRECTIONS

Redox-responsive nanocarriers achieve a near-to-zero premature release of the drug, thus avoiding off-site toxicity associated with the free drug. This bears great potential for the development of more effective drug delivery with better pharmacokinetics and pharmacodynamics.

Intestine-penetrating, pH-sensitive and double-layered nanoparticles for oral delivery of doxorubicin with reduced toxicity

Herein, CMC-coated double-layered nanoparticles were prepared to induce the oral toxicity of doxorubicin via the intestinal absorption effect.

Redox nanoparticles: synthesis, properties and perspectives of use for treatment of neurodegenerative diseases

Oxidative stress (OS) and nitrative stress (NS) accompany many diseases, including Alzheimer's disease (AD) and Parkinson's disease (PD). Antioxidants have been proposed to counteract OS/NS in these diseases. Nevertheless, the effects of antioxidants are limited and new, more efficient antioxidants are searched for. Redox-active nanoparticles (RNPs), containing antioxidants create a new therapeutical perspective. This review examines the recent literature describing synthesis and potential applications of cerium oxide RNPs, boron cluster-containing and silica containing RNPs, Gd₃N_@C₈₀ encapsulated RNPs, and concentrates on nitroxide-containing RNPs. Nitroxides are promising antioxidants, preventing inter alia glycation and nitration, but their application poses several problems. It can be expected that application of RNPs containing covalently bound nitroxides, showing low toxicity and able to penetrate the blood-brain barrier will be more efficient in the treatment of neurodegenerative disease, in particular AD and PD basing on their effects in cellular and animal models of neurodegenerative diseases.

Dietary Supplementation of Selenoneine-Containing Tuna Dark Muscle Extract Effectively Reduces Pathology of Experimental Colorectal Cancers in Mice

Selenoneine is an ergothioneine analog with greater antioxidant activity and is the major form of organic selenium in the blood, muscles, and other tissues of tuna. The aim of this study was to determine whether a selenoneine-rich diet exerts antioxidant activities that can prevent carcinogenesis in two types of colorectal cancer model in mice. We administrated selenoneine-containing tuna dark muscle extract (STDME) to mice for one week and used azoxymethane (AOM) and dextran sodium sulfate (DSS) for inducing colorectal carcinogenesis. Next, we examined the incidence of macroscopic polyps and performed functional analysis of immune cells from the spleen. In the AOM/DSS-induced colitis-associated cancer (CAC) model, the oral administration of STDME significantly decreased tumor incidence and inhibited the accumulation of myeloid-derived suppressor cells (MDSCs) while also inhibiting the downregulation of interferon-γ (IFN-γ) production during carcinogenesis. These results suggest that dietary STDME may be an effective agent for reducing colorectal tumor progression.

[Design of New Cancer Nanotherapeutics Which Controls Active Gaseous Molecules in Vivo]

　Reactive oxygen species (ROS) are known to play a variety of roles in many important events in vivo. However, the overproduction of ROS causes serious adverse effects to living beings. Numerous drugs have been developed and applied to reduce overproduced ROS, but these have failed to be clinically approved. Since most of these antioxidants are low molecular weight (LMW) compounds, they not only eliminate ROS related to diseases, but also destroy the essential redox reactions necessary for basic energy production in living bodies. In the mitochondria of normal cells, ATP production by electron transport chain is carried out, and a large amount of ROS is thus generated; however, LMW antioxidants also nonspecifically enter normal cells and affect essential oxidation. To improve selective antioxidant properties without damage to these normal redox reactions, we designed new polymer antioxidants. These polymers have self-assembling properties and form nanoparticles (RNPs) in which nitroxide radicals covalently attach as a side chain of the hydrophobic segment in the amphiphilic block copolymers, which are then compartmentalized into the solid core of the nanoparticles. Unlike LMW antioxidants, RNPs have extremely poor in vivo toxicity, as they are less likely to be taken up by healthy cells. Since one of RNPs, RNP^N has pH-sensitive disintegration properties, it disintegrates at pH lower than 7.0 such as solid tumors and inflammation. It can therefore be used in pH responsive bioimaging and therapy. We have used RNPs experimentally in the treatment of several diseases and confirmed their effectiveness.

Protection of Coral Larvae from Thermally Induced Oxidative Stress by Redox Nanoparticles

Coral reefs are one of the most biologically diverse and economically important ecosystems on earth. However, the destruction of coral reefs has been reported worldwide owing to rising seawater temperature associated with global warming. In this study, we investigated the potential of a redox nanoparticle (RNP^O) to scavenge reactive oxygen species (ROS), which are overproduced under heat stress and play a crucial role in causing coral mortality. When reef-building coral (Acropora tenuis) larvae, without algal symbionts, were exposed to thermal stress at 33 °C, RNP^O treatment significantly increased the survival rate. Proteome analysis of coral larvae was performed using nano-liquid chromatography-tandem mass spectrometry for the first time. The results revealed that several proteins related to ROS-induced oxidative stress were specifically identified in A. tenuis larvae without RNP^O treatment, whereas these proteins were absent in RNP^O-treated larvae, which suggested that RNP^O effectively scavenged ROS from A. tenuis larvae. Results from this study indicate that RNP^O treatment can reduce ROS in aposymbiotic coral larvae and would be a promising approach for protecting corals from thermal stress.

Nitroxide radical-containing nanoparticles attenuate tumorigenic potential of triple negative breast cancer

The critical importance of reactive oxygen species (ROS) as oncogene activators and essential secondary messengers in cancer cell survival have been widely reported. Since oxidative stress has been implicated as being pivotal in various cancers, antioxidant therapy seems an apt strategy to abrogate ROS-mediated cellular processes to attenuate cancers. We therefore synthesized ROS scavenging nitroxide radical-containing nanoparticles (RNPs); pH insensitive RNP^O and pH sensitive RNP^N, to impede the proliferative and metastatic characteristics of the triple negative breast cancer cell line, MDA-MB-231, both in vitro and in vivo. RNPs significantly curtailed the proliferative and clonogenic potential of MDA-MB-231 and MCF-7 cell lines. Inhibition of ROS-mediated migratory and invasive characteristics of MDA-MB-231, via down regulation of NF-κB and MMP-2, was also confirmed. Furthermore, a significant anti-tumor and anti-metastatic potential of RNPs was observed in an MDA-MB-231 mouse xenograft model. Such tumoricidal effects of RNPs were attained with negligible adverse effects, compared to conventional low molecular weight antioxidants, TEMPOL. Thus, the tumoricidal effects of RNPs are suggestive of insights on precedence of nanoparticle-based therapeutics over current low molecular weight antioxidants to curtail ROS-induced tumorigenesis of various cancers.

Nitroxide radical polymers – a versatile material class for high-tech applications

A comprehensive summary of synthetic strategies for the preparation of nitroxide radical polymer materials and a state-of-the-art perspective on their latest and most exciting applications.