Fluorocoxib A loaded nanoparticles enable targeted visualization of cyclooxygenase-2 in inflammation and cancer

Fluorescent Probes for Disease Diagnosis

The identification and detection of disease-related biomarkers is essential for early clinical diagnosis, evaluating disease progression, and for the development of therapeutics. Possessing the advantages of high sensitivity and selectivity, fluorescent probes have become effective tools for monitoring disease-related active molecules at the cellular level and in vivo. In this review, we describe current fluorescent probes designed for the detection and quantification of key bioactive molecules associated with common diseases, such as organ damage, inflammation, cancers, cardiovascular diseases, and brain disorders. We emphasize the strategies behind the design of fluorescent probes capable of disease biomarker detection and diagnosis and cover some aspects of combined diagnostic/therapeutic strategies based on regulating disease-related molecules. This review concludes with a discussion of the challenges and outlook for fluorescent probes, highlighting future avenues of research that should enable these probes to achieve accurate detection and identification of disease-related biomarkers for biomedical research and clinical applications.

Novel biocatalysts based on enzymes in complexes with nano- and micromaterials

In today's world, there is a wide array of materials engineered at the nano- and microscale, with numerous applications attributed to these innovations. This review aims to provide a concise overview of how nano- and micromaterials are utilized for enzyme immobilization. Enzymes act as eco-friendly biocatalysts extensively used in various industries and medicine. However, their widespread adoption faces challenges due to factors such as enzyme instability under different conditions, resulting in reduced effectiveness, high costs, and limited reusability. To address these issues, researchers have explored immobilization techniques using nano- and microscale materials as a potential solution. Such techniques offer the promise of enhancing enzyme stability against varying temperatures, solvents, pH levels, pollutants, and impurities. Consequently, enzyme immobilization remains a subject of great interest within both the scientific community and the industrial sector. As of now, the primary goal of enzyme immobilization is not solely limited to enabling reusability and stability. It has been demonstrated as a powerful tool to enhance various enzyme properties and improve biocatalyst performance and characteristics. The integration of nano- and microscale materials into biomedical devices is seamless, given the similarity in size to most biological systems. Common materials employed in developing these nanotechnology products include synthetic polymers, carbon-based nanomaterials, magnetic micro- and nanoparticles, metal and metal oxide nanoparticles, metal-organic frameworks, nano-sized mesoporous hydrogen-bonded organic frameworks, protein-based nano-delivery systems, lipid-based nano- and micromaterials, and polysaccharide-based nanoparticles.

Development of Pluoronic nanoparticles of fluorocoxib A for endoscopic fluorescence imaging of colonic adenomas

Significance

Current white light colonoscopy suffers from many limitations that allow 22% to 32% of preneoplastic lesions to remain undetected. This high number of false negatives contributes to the appearance of interval malignancies, defined as neoplasms diagnosed between screening colonoscopies at a rate of 2% to 6%.

Aim

The shortcomings of today's white light-based colorectal cancer screening are addressed by colonoscopic fluorescence imaging of preneoplastic lesions using targeted fluorescent agents to enhance contrast between the lesion and the surrounding normal colonic epithelium.

Approach

We describe the development of Pluronic® nanoparticles of fluorocoxib A (FA), a fluorescent cyclooxygenase-2 (COX-2) inhibitor that enables targeted imaging of inflammation and cancer in numerous animal models, for endoscopic florescence imaging of colonic adenomas.

Results

We formulated FA, a fluorescent COX-2 inhibitor, or fluorocoxib negative control (FNC), a nontargeted fluorophore and a negative control for FA, in micellar nanoparticles of FDA approved Pluronic tri-block co-polymer using a bulk solvent evaporation method. This afforded FA-loaded micellar nanoparticles (FA-NPs) or FNC-loaded micellar nanoparticles (FNC-NPs) with the hydrodynamic diameters (D h ) of 45.7 ± 2.5    nm and 44.9 ± 3.8    nm and the zeta potentials ( ζ ) of - 1.47 ± 0.3    mV and - 1.64 ± 0.5    mV , respectively. We intravenously injected B6;129 mice bearing colonic adenomas induced by azoxymethane and dextran-sodium sulfate with FA-loaded Pluronic nanoparticles (FA-NPs). The diffusion-mediated local FA release and its binding to COX-2 enzyme allowed for clear detection of adenomas with high signal-to-noise ratios. The COX-2 targeted delivery and tumor retention were validated by negligible tumor fluorescence detected upon colonoscopic imaging of adenoma-bearing mice injected with Pluronic nanoparticles of FNC or of animals predosed with the COX-2 inhibitor, celecoxib, followed by intravenous dosing of FA-NPs.

Conclusions

These results demonstrate that the formulation of FA in Pluronic nanoparticles overcomes a significant hurdle to its clinical development for early detection of colorectal neoplasms by fluorescence endoscopy.

ROS-Responsive Glycopolymeric Nanoparticles for Enhanced Drug Delivery to Macrophages

Macrophages play a diverse, key role in many pathologies, including inflammatory diseases, cardiovascular diseases, and cancer. However, many therapeutic strategies targeting macrophages suffer from systemic off-target toxicity resulting in notoriously narrow therapeutic windows. To address this shortcoming, the development of poly(propylene sulfide)-b-poly(methacrylamidoglucopyranose) [PPS-b-PMAG] diblock copolymer-based nanoparticles (PMAG NPs) capable of targeting macrophages and releasing drug in the presence of reactive oxygen species (ROS) is reported. PMAG NPs have desirable physicochemical properties for systemic drug delivery, including slightly negative surface charge, ≈100 nm diameter, and hemo-compatibility. Additionally, due to the presence of PPS in the NP core, PMAG NPs release drug cargo preferentially in the presence of ROS. Importantly, PMAG NPs display high cytocompatibility and are taken up by macrophages in cell culture at a rate ≈18-fold higher than PEGMA NPs-NPs composed of PPS-b-poly(oligoethylene glycol methacrylate). Computational studies indicate that PMAG NPs likely bind with glucose transporters such as GLUT 1/3 on the macrophage cell surface to facilitate high levels of internalization. Collectively, this study introduces glycopolymeric NPs that are uniquely capable of both receptor-ligand targeting to macrophages and ROS-dependent drug release and that can be useful in many immunotherapeutic settings.

Discovery of a Redox-Activatable Chemical Probe for Detection of Cyclooxygenase-2 in Cells and Animals

Cyclooxygenase-2 (COX-2) expression is up-regulated in inflammatory tissues and many premalignant and malignant tumors. Assessment of COX-2 protein in vivo, therefore, promises to be a powerful strategy to distinguish pathologic cells from normal cells in a complex disease setting. Herein, we report the first redox-activatable COX-2 probe, fluorocoxib Q (FQ), for in vivo molecular imaging of pathogenesis. FQ inhibits COX-2 selectively in purified enzyme and cell-based assays. FQ exhibits extremely low fluorescence and displays time- and concentration-dependent fluorescence enhancement upon exposure to a redox environment. FQ enters the cells freely and binds to the COX-2 enzyme. FQ exhibits high circulation half-life and metabolic stability sufficient for target site accumulation and demonstrates COX-2-targeted uptake and retention in cancer cells and pathologic tissues. Once taken up, it undergoes redox-mediated transformation into a fluorescent compound fluorocoxib Q-H that results in high signal-to-noise contrast and differentiates pathologic tissues from non-pathologic tissues for real-time in vivo imaging.

Optimizing an Antioxidant TEMPO Copolymer for Reactive Oxygen Species Scavenging and Anti-Inflammatory Effects in Vivo

Oxidative stress is broadly implicated in chronic, inflammatory diseases because it causes protein and lipid damage, cell death, and stimulation of inflammatory signaling. Supplementation of innate antioxidant mechanisms with drugs such as the superoxide dismutase (SOD) mimetic compound 2,2,6,6-tetramethylpiperidin-1-oxyl (TEMPO) is a promising strategy for reducing oxidative stress-driven pathologies. TEMPO is inexpensive to produce and has strong antioxidant activity, but it is limited as a drug due to rapid clearance from the body. It is also challenging to encapsulate into micellar nanoparticles or polymer microparticles, because it is a small, water soluble molecule that does not efficiently load into hydrophobic carrier systems. In this work, we pursued a polymeric form of TEMPO [poly(TEMPO)] to increase its molecular weight with the goal of improving in vivo bioavailability. High density of TEMPO on the poly(TEMPO) backbone limited water solubility and bioactivity of the product, a challenge that was overcome by tuning the density of TEMPO in the polymer by copolymerization with the hydrophilic monomer dimethylacrylamide (DMA). Using this strategy, we formed a series of poly(DMA-co-TEMPO) random copolymers. An optimal composition of 40 mol % TEMPO/60 mol % DMA was identified for water solubility and O2•- scavenging in vitro. In an air pouch model of acute local inflammation, the optimized copolymer outperformed both the free drug and a 100% poly(TEMPO) formulation in O2•- scavenging, retention, and reduction of TNFα levels. Additionally, the optimized copolymer reduced ROS levels after systemic injection in a footpad model of inflammation. These results demonstrate the benefit of polymerizing TEMPO for in vivo efficacy and could lead to a useful antioxidant polymer formulation for next-generation anti-inflammatory treatments.

Targeted molecular imaging of head and neck squamous cell carcinoma: a window into precision medicine

Tumor biomarkers play important roles in tumor growth, invasion, and metastasis. Imaging of specific biomarkers will help to understand different biological activities, thereby achieving precise medicine for each head and neck squamous cell carcinoma (HNSCC) patient. Here, we describe various molecular targets and molecular imaging modalities for HNSCC imaging. An extensive search was undertaken in the PubMed database with the keywords including “HNSCC,” “molecular imaging,” “biomarker,” and “multimodal imaging.” Imaging targets in HNSCC consist of the epidermal growth factor receptor, cluster of differentiation 44 variant 6 (CD44v6), and mesenchymal-epithelial transition factor and integrins. Targeted molecular imaging modalities in HNSCC include optical imaging, ultrasound, magnetic resonance imaging, positron emission tomography, and single-photon emission computed tomography. Making the most of each single imaging method, targeted multimodal imaging has a great potential in the accurate diagnosis and therapy of HNSCC. By visualizing tumor biomarkers at cellular and molecular levels in vivo, targeted molecular imaging can be used to identify specific genetic and metabolic aberrations, thereby accelerating personalized treatment development for HNSCC patients.

3-B-RUT, a derivative of RUT, protected against alcohol-induced liver injury by attenuating inflammation and oxidative stress

Alcoholic liver disease (ALD) is the most common chronic liver disease worldwide. Currently, there is no definitive treatment for alcohol-induced liver injury (ALI). Inflammatory response and oxidative stress play a crucial role in ALI. Cyclooxygenase 2 (COX-2) can be induced by inflammation and it has been reported that the enhanced expression of COX-2 in alcoholic liver injury. Rutaecarpine (RUT) was extracted from evodia rutaecarpa. RUT has a wide range of pharmacological activities. In order to increase its anti-inflammatory activity, our group introduced sulfonyl group to synthesized the 3-[2-(trifluoromethoxy)benzenesulfonamide]-rutaecarpine (3-B-RUT). In this study, we explored the protective effect of 3-B-RUT on alcoholic liver injury in vivo and in vitro and preliminarily explore its mechanism. Mice ALI model was established according to the chronic-plus-binge ethanol model. Results showed that 3-B-RUT (20 μg/kg) attenuated alcohol-induced liver injury and suppressed liver inflammation and oxidative stress, and the effect was comparable to RUT (20 mg/kg). In vitro results are consistent with in vivo results. Mechanistically, the 3-B-RUT might suppress inflammatory response and oxidative stress by regulating activation of NF-κB/COX-2 pathway. In summary, 3-B-RUT, a derivative of RUT, may be a promising clinical candidate for ALI treatment.

Targeted Detection of Cyclooxygenase-1 in Ovarian Cancer

Overexpression of cyclooxygenase-1 (COX-1) is associated with the initiation and progression of ovarian cancer, and targeted imaging of COX-1 is a promising strategy for early detection of this disease. We report the discovery of N-[(5-carboxy-X-rhodaminyl)but-4-yl]-3-(1-(4-methoxyphenyl)-5-(p-tolyl)-1H-pyrazol-3-yl)propenamide (CMP) as the first COX-1-targeted optical agent for imaging of ovarian cancer. CMP exhibits light emission at 604 nm (λ_max), thereby minimizing tissue autofluorescence interference. In both purified enzyme and COX-1-expressing human ovarian adenocarcinoma (OVCAR-3) cells, CMP inhibits COX-1 at low nanomolar potencies (IC₅₀ = 94 and 44 nM, respectively). CMP's selective binding to COX-1 in OVCAR-3 cells was visualized microscopically as intense intracellular fluorescence. In vivo optical imaging of xenografts in athymic nude mice revealed COX-1-dependent accumulation of CMP in COX-1-expressing mouse ovarian surface epithelial carcinoma (ID8-NGL) and OVCAR-3 cells. These results establish proof-of-principle for the feasibility of targeting COX-1 in the development of new imaging and therapeutic strategies for ovarian cancer.

Molecular Imaging of Inflammation in Osteoarthritis Using a Water-Soluble Fluorocoxib

Clinical imaging approaches to detect inflammatory biomarkers, such as cyclooxygenase-2 (COX-2), may facilitate the diagnosis and therapy of inflammatory diseases. To this end, we report the discovery of N-[(rhodamin-X-yl)but-4-yl]-2-[1-(4-chlorobenzoyl)-5-methoxy-2-methyl-1H-indol-3-yl]acetamide chloride salt (fluorocoxib D), a hydrophilic analog of fluorocoxib A. Fluorocoxib D inhibits COX-2 selectively in purified enzyme preparations and cells. It exhibits adequate photophysical properties to enable detection of COX-2 in intact cells, in a mouse model of carrageenan-induced acute footpad inflammation and inflammation in a mouse model of osteoarthritis. COX-2-selectivity was verified either by blocking the enzyme's active site with celecoxib or by molecular imaging with nontargeted 5-carboxy-X-rhodamine dye. These data indicate that fluorocoxib D is an ideal candidate for early detection of inflammatory or neoplastic lesions expressing elevated levels of COX-2.

Design and Synthesis of a Novel NIR Celecoxib-Based Fluorescent Probe for Cyclooxygenase-2 Targeted Bioimaging in Tumor Cells

Cyclooxygenase-2 (COX-2) imaging agents are potent tools for early cancer diagnosis. Almost all of the COX2 imaging agents using celecoxib as backbone were chemically modified in the position of N-atom in the sulfonamide group. Herein, a novel COX-2 probe (CCY-5) with high targeting ability and a near-infrared wavelength (achieved by attaching a CY-5 dye on the pyrazole ring of celecoxib using a migration strategy) was evaluated for its ability to probe COX-2 in human cancer cells. CCY-5 is expected to have high binding affinity for COX-2 based on molecular docking and enzyme inhibition assay. Meanwhile, CCY-5 caused stronger fluorescence imaging of COX-2 overexpressing cancer cells (Hela and SCC-9 cells) than that of normal cell lines (RAW 264.7 cells). Lipopolysaccharide (LPS) treated RAW264.7 cells revealed an enhanced fluorescence as LPS was known to induce COX-2 in these cells. In inhibitory studies, a markedly reduced fluorescence intensity was observed in cancer cells, when they were co-treated with a COX-2 inhibitor celecoxib. Therefore, CCY-5 may be a selective bioimaging agent for cancer cells overexpressing COX-2 and could be useful as a good monitoring candidate for effective diagnosis and therapy in cancer treatment.

Pharmacokinetic characterization of fluorocoxib D, a cyclooxygenase-2-targeted optical imaging agent for detection of cancer

SIGNIFICANCE

Fluorocoxib D, N-[(rhodamin-X-yl)but-4-yl]-2-[1-(4-chlorobenzoyl)-5-methoxy-2-methyl-1H-indol-3-yl]acetamide, is a water-soluble optical imaging agent to detect cyclooxygenase-2 (COX-2)-expressing cancer cells.

AIM

We evaluated the pharmacokinetic and safety properties of fluorocoxib D and its ability to detect cancer cells in vitro and in vivo.

APPROACH

Pharmacokinetic parameters of fluorocoxib D were assessed from plasma collected at designated time points after intravenous administration of 1  mg  /  kg fluorocoxib D in six research dogs using a high-performance liquid chromatography analysis. Safety of fluorocoxib D was assessed for 3 days after its administration using physical assessment, complete blood count, serum chemistry profile, and complete urinalysis in six research dogs. The ability of fluorocoxib D to detect COX-2-expressing cancer cells was performed using human 5637 cells in vitro and during rhinoscopy evaluation of specific fluorocoxib D uptake by canine cancer cells in vivo.

RESULTS

No evidence of toxicity and no clinically relevant adverse events were noted in dogs. Peak concentration of fluorocoxib D (114.8  ±  50.5  ng  /  ml) was detected in plasma collected at 0.5 h after its administration. Pretreatment of celecoxib blocked specific uptake of fluorocoxib D in COX-2-expressing human 5637 cancer cells. Fluorocoxib D uptake was detected in histology-confirmed COX-2-expressing head and neck cancer during rhinoscopy in a client-owned dog in vivo. Specific tumor-to-normal tissue ratio of detected fluorocoxib D signal was in an average of 3.7  ±  0.9 using Image J analysis.

CONCLUSIONS

Our results suggest that fluorocoxib D is a safe optical imaging agent used for detection of COX-2-expressing cancers and their margins during image-guided minimally invasive biopsy and surgical procedures.

Lipoxin A4 attenuates uric acid-activated, NADPH oxidase-dependent oxidative stress by interfering with translocation of p47phox in human umbilical vein endothelial cells

LipoxinA4 (LXA4) is a well-known key mediator of endogenous anti-inflammation and of the resolution of inflammation. Considerable oxidative stress occurs during inflammation due to the generation of reactive oxidative species (ROS). Moreover, high levels of uric acid (UA) contribute to endothelial cell dysfunction, which can promote disease-related morbidity, and NADPH oxidase-derived ROS are crucial regulatory factors in these responses. However, LXA4 also has the potential to reduce oxidative stress. The aim of the present study was to examine whether LXA4 could suppress UA-induced oxidative stress in human umbilical vein endothelial cells (HUVECs) and to investigate its mechanisms of action in vitro. HUVECs were incubated with or without LXA4, followed by the addition of UA. ROS levels were then measured using 2,7-dichlorodihydrofluorescein diacetate and lucigenin-enhanced chemiluminescence was used to evaluate NADPH oxidase activity. p47phox or p22phox small interfering (si)RNA were transfected into HUVECs and protein levels of p47phox were detected using western blot analysis. LXA4 significantly inhibited UA-induced generation of ROS to the same extent as the NADPH oxidase inhibitor, diphenyleneiodonium chloride. Notably, transfection of p47phox siRNA attenuated the generation of ROS and the activation of NADPH oxidase. Cells transfected with p22phox siRNA demonstrated a significant reduction in the expression of p47phox on the membrane. Further experiments demonstrated that LXA4 interfered with the transfer of p47phox from the cytoplasm to the cell membrane. These findings suggested that LXA4 inhibited the release of NADPH oxidase derived ROS in HUVECs stimulated by UA. A potential mechanism of action underlying this effect could be LXA4-mediated suppression of NADPH oxidase activity, leading to inhibition of p47phox translocation from the cytoplasm to the cell membrane.

Tuning Ligand Density To Optimize Pharmacokinetics of Targeted Nanoparticles for Dual Protection against Tumor-Induced Bone Destruction

Breast cancer patients are at high risk for bone metastasis. Metastatic bone disease is a major clinical problem that leads to a reduction in mobility, increased risk of pathologic fracture, severe bone pain, and other skeletal-related events. The transcription factor Gli2 drives expression of parathyroid hormone-related protein (PTHrP), which activates osteoclast-mediated bone destruction, and previous studies showed that Gli2 genetic repression in bone-metastatic tumor cells significantly reduces tumor-induced bone destruction. Small molecule inhibitors of Gli2 have been identified; however, the lipophilicity and poor pharmacokinetic profile of these compounds have precluded their success in vivo. In this study, we designed a bone-targeted nanoparticle (BTNP) comprising an amphiphilic diblock copolymer of poly[(propylene sulfide)-block-(alendronate acrylamide-co-N,N-dimethylacrylamide)] [PPS-b-P(Aln-co-DMA)] to encapsulate and preferentially deliver a small molecule Gli2 inhibitor, GANT58, to bone-associated tumors. The mol % of the bisphosphonate Aln in the hydrophilic polymer block was varied in order to optimize BTNP targeting to tumor-associated bone by a combination of nonspecific tumor accumulation (presumably through the enhanced permeation and retention effect) and active bone binding. Although 100% functionalization with Aln created BTNPs with strong bone binding, these BTNPs had highly negative zeta-potential, resulting in shorter circulation time, greater liver uptake, and less distribution to metastatic tumors in bone. However, 10 mol % of Aln in the hydrophilic block generated a formulation with a favorable balance of systemic pharmacokinetics and bone binding, providing the highest bone/liver biodistribution ratio among formulations tested. In an intracardiac tumor cell injection model of breast cancer bone metastasis, treatment with the lead candidate GANT58-BTNP formulation decreased tumor-associated bone lesion area 3-fold and increased bone volume fraction in the tibiae of the mice 2.5-fold. Aln conferred bone targeting to the GANT58-BTNPs, which increased GANT58 concentration in the tumor-associated bone relative to untargeted NPs, and also provided benefit through the direct antiresorptive therapeutic function of Aln. The dual benefit of the Aln in the BTNPs was supported by the observations that drug-free Aln-containing BTNPs improved bone volume fraction in bone-tumor-bearing mice, while GANT58-BTNPs created better therapeutic outcomes than both unloaded BTNPs and GANT58-loaded untargeted NPs. These findings suggest GANT58-BTNPs have potential to potently inhibit tumor-driven osteoclast activation and resultant bone destruction in patients with bone-associated tumor metastases.

Reactive oxygen species-responsive drug delivery systems for the treatment of neurodegenerative diseases

Neurodegenerative diseases and disorders seriously impact memory and cognition and can become life-threatening. Current medical techniques attempt to combat these detrimental effects mainly through the administration of neuromedicine. However, drug efficacy is limited by rapid dispersal of the drugs to off-target sites while the site of administration is prone to overdose. Many neuropathological conditions are accompanied by excessive reactive oxygen species (ROS) due to the inflammatory response. Accordingly, ROS-responsive drug delivery systems have emerged as a promising solution. To guide intelligent and comprehensive design of ROS-responsive drug delivery systems, this review article discusses the two following topics: (1) the biology of ROS in both healthy and diseased nervous systems and (2) recent developments in ROS-responsive, drug delivery system design. Overall, this review article would assist efforts to make better decisions about designing ROS-responsive, neural drug delivery systems, including the selection of ROS-responsive functional groups.

Systemic delivery of a Gli inhibitor via polymeric nanocarriers inhibits tumor-induced bone disease

Solid tumors frequently metastasize to bone and induce bone destruction leading to severe pain, fractures, and other skeletal-related events (SREs). Osteoclast inhibitors such as bisphosphonates delay SREs but do not prevent skeletal complications or improve overall survival. Because bisphosphonates can cause adverse side effects and are contraindicated for some patients, we sought an alternative therapy to reduce tumor-associated bone destruction. Our previous studies identified the transcription factor Gli2 as a key regulator of parathyroid hormone-related protein (PTHrP), which is produced by bone metastatic tumor cells to promote osteoclast-mediated bone destruction. In this study, we tested the treatment effect of a Gli antagonist GANT58, which inhibits Gli2 nuclear translocation and PTHrP expression in tumor cells. In initial testing, GANT58 did not have efficacy in vivo due to its low water solubility and poor bioavailability. We therefore developed a micellar nanoparticle (NP) to encapsulate and colloidally stabilize GANT58, providing a fully aqueous, intravenously injectable formulation based on the polymer poly(propylene sulfide)₁₃₅-b-poly[(oligoethylene glycol)₉ methyl ether acrylate]₁₇ (PPS₁₃₅-b-POEGA₁₇). POEGA forms the hydrophilic NP surface while PPS forms the hydrophobic NP core that sequesters GANT58. In response to reactive oxygen species (ROS), PPS becomes hydrophilic and degrades to enable drug release. In an intratibial model of breast cancer bone metastasis, treatment with GANT58-NPs decreased bone lesion area by 49% (p<.01) and lesion number by 38% (p<.05) and resulted in a 2.5-fold increase in trabecular bone volume (p<.001). Similar results were observed in intracardiac and intratibial models of breast and lung cancer bone metastasis, respectively. Importantly, GANT58-NPs reduced tumor cell proliferation but did not alter mesenchymal stem cell proliferation or osteoblast mineralization in vitro, nor was there evidence of cytotoxicity after repeated in vivo treatment. Thus, inhibition of Gli2 using GANT58-NPs is a potential therapy to reduce bone destruction that should be considered for further testing and development toward clinical translation.

Silk fibroin-based nanotherapeutics: application in the treatment of colonic diseases

The incidence of colonic diseases (e.g., inflammatory bowel diseases and colon cancer) is rapidly rising. Nanotherapeutic has been considered as a promising strategy in the treatment of colonic diseases. Silk fibroin (SF) has been widely used as a drug-carrier matrix. Interestingly, SF-based nanoparticles (SFNPs) have intrinsic anti-inflammatory activity, wound healing capacity and lysosomal environment-responsive drug-release property. With further investigations, the sequences of SF molecules could be precisely modified through chemical reactions or transgenic techniques to greatly improve the properties of SFNPs. Here, we review recent advances in the application of SFNPs toward the treatment of colonic diseases. We also discuss future developments that might improve the anti-inflammatory and anti-colon cancer activities of SF-based nanotherapeutics.

Detection of tyrosine kinase inhibitors-induced COX-2 expression in bladder cancer by fluorocoxib A

Among challenges of targeted therapies is the activation of alternative pro-survival signaling pathways in cancer cells, resulting in an acquired drug resistance. Cyclooxygenase-2 (COX-2) is overexpressed in bladder cancer cells, making it an attractive molecular target for the detection and treatment of cancer. Fluorocoxib A is an optical imaging agent that selectively targets COX-2. In this study, we evaluated the ability of fluorocoxib A to monitor the responses of bladder cancer to targeted therapies in vivo. The effects of several tyrosine kinase inhibitors (TKIs: axitinib, AB1010, toceranib, imatinib, erlotinib, gefitinib, imatinib, sorafenib, vandetanib, SP600125, UO126, and AZD 5438) on COX-2 expression were validated in ten human and canine bladder cancer cell lines (J82, RT4, T24, UM-UC-3, 5637, SW780, TCCSUP, K9TCC#1Lillie, K9TCC#2Dakota, K9TCC#5Lilly) in vitro. The effects of TKIs on bladder cancer in vivo were evaluated using the COX-2-expressing K9TCC#5Lilly xenograft mouse model and detected by fluorocoxib A. The increased COX-2 expression was detected by all tested TKIs in at least one of the tested COX-2-expressing bladder cancer cell lines (5637, SW780, TCCSUP, K9TCC#1Lillie, K9TCC#2Dakota, and K9TCC#5Lilly) in vitro. In addition, fluorocoxib A uptake correlated with the AB1010- and imatinib-induced COX-2 expression in the K9TCC#5Lilly xenografts in vivo. In conclusion, these results indicate that fluorocoxib A could be used for the monitoring the early responses to targeted therapies in COX-2-expressing bladder cancer.

A novel near-infrared fluorescent probe for monitoring cyclooxygenase-2 in inflammation and tumor

Targeting cyclooxygenase-2 (COX-2) for molecular imaging is an attractive approach applicable for its overexpression in inflammation and many malignancies. Herein, for monitoring COX-2, we synthesize a specific COX-2 probe celecoxib-MPA probe (CMP), based on celecoxib and a water-soluble near-infrared dye dye ICG-Der-02 (MPA). Its high affinity for binding to COX-2 is verified by molecular docking, dynamics simulation and inhibition assay. At cellular level, CMP selectively accumulates in cytoplasm of COX-2-positive cells. in vivo assays, probe guided-imaging in inflamed or cancerous tissues confirms that CMP can bind to the locally endogenic COX-2 and exhibit intense fluorescence. Importantly, we further prove the targeting specificity of CMP as the fluorescence is significantly reduced by blocking COX-2 active site through preinjection with celecoxib. The results suggest that the probe CMP, with favorable hydrophilic property, good biocompatibility, long-term observation, excellent targeting ability and optical imaging capability, could serve as a promising probe for real-time monitoring COX-2 in inflammation and tumor.

ROS-Responsive Chalcogen-Containing Polycarbonates for Photodynamic Therapy

Reactive oxygen species (ROS)-responsive polymers have attracted attention for their potential in photodynamic therapy. Herein, we report the ROS-responsive aliphatic polycarbonates prepared by the ring-opening polymerization (ROP) of three six-membered cyclic carbonate monomers with ethyl selenide, phenyl selenide or ethyl telluride groups. Under catalysis of 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU), all three monomers underwent the controlled anionic ROP, showing a feature of equilibrium polymerization due to the bulky effect of 5,5-disubstituents. With PEG macroinitiator, three series amphiphilic block copolymers were prepared. They could form spherical nanoparticles of ∼100 nm, which were stable in neutral phosphate buffer but dissociated rapidly under triggering of H₂O₂. We studied the H₂O₂-induced oxidation profiles of selenide- or telluride-containing small molecules by ¹H NMR and revealed the factors that affect the oxidation kinetics and products. On this basis, the oxidative degradation mechanism of the copolymer nanoparticles has been clarified. Under the same oxidative condition, the telluride-containing nanoparticle degraded with the fastest rate while the phenyl selenide-based one degraded most slowly. These ROS-responsive nanoparticles could load photosensitizer chlorin e6 (Ce6) and anticancer drug doxorubicin (DOX). Under red light irradiation, Ce6-sensitized production of ¹O₂ that triggered the degradation of nanoparticles, resulting in an accelerated payload release. In vitro cytotoxicity assays demonstrate that the nanoparticles coloaded with DOX and Ce6 exhibited a synergistic cell-killing effect to MCF-7 cells, representing a novel responsive nanoplatform for PDT and/or chemotherapy.

Thermogelling, ABC Triblock Copolymer Platform for Resorbable Hydrogels with Tunable, Degradation-Mediated Drug Release

Clinical application of injectable, thermoresponsive hydrogels is hindered by lack of degradability and controlled drug release. To overcome these challenges, a family of thermoresponsive, ABC triblock polymer-based hydrogels has been engineered to degrade and release drug cargo through either oxidative or hydrolytic/enzymatic mechanisms dictated by the "A" block composition. Three ABC triblock copolymers are synthesized with varying "A" blocks, including oxidation-sensitive poly(propylene sulfide), slow hydrolytically/enzymatically degradable poly(ε-caprolactone), and fast hydrolytically/enzymatically degradable poly(D,L-lactide-co-glycolide), forming the respective formulations PPS135-b-PDMA152-b-PNIPAAM225 (PDN), PCL85-b-PDMA150-b-PNIPAAM150 (CDN), and PLGA60-b-PDMA148-b-PNIPAAM152 (LGDN). For all three polymers, hydrophilic poly(N,N-dimethylacrylamide) and thermally responsive poly(N-isopropylacrylamide) comprise the "B" and "C" blocks, respectively. These copolymers form micelles in aqueous solutions at ambient temperature that can be preloaded with small molecule drugs. These solutions quickly transition into hydrogels upon heating to 37 °C, forming a supra-assembly of physically crosslinked, drug-loaded micelles. PDN hydrogels are selectively degraded under oxidative conditions while CDN and LGDN hydrogels are inert to oxidation but show differential rates of hydrolytic/enzymatic decomposition. All three hydrogels are cytocompatible in vitro and in vivo, and drug-loaded hydrogels demonstrate differential release kinetics in vivo corresponding with their specific degradation mechanism. These collective data highlight the potential cell and drug delivery use of this tunable class of ABC triblock polymer thermogels.

New perspectives in nanotherapeutics for chronic respiratory diseases

According to the World Health Organization (WHO), hundreds of millions of people of all ages and in all countries suffer from chronic respiratory diseases, with particular negative consequences such as poor health-related quality of life, impaired work productivity, and limitations in the activities of daily living. Chronic obstructive pulmonary disease, asthma, occupational lung diseases (such as silicosis), cystic fibrosis, and pulmonary arterial hypertension are the most common of these diseases, and none of them are curable with current therapies. The advent of nanotechnology holds great therapeutic promise for respiratory conditions, because non-viral vectors are able to overcome the mucus and lung remodeling barriers, increasing pharmacologic and therapeutic potency. It has been demonstrated that the extent of pulmonary nanoparticle uptake depends not only on the physical and chemical features of nanoparticles themselves, but also on the health status of the organism; thus, the huge diversity in nanotechnology could revolutionize medicine, but safety assessment is a challenging task. Within this context, the present review discusses some of the major new perspectives in nanotherapeutics for lung disease and highlights some of the most recent studies in the field.

Homing in on an intracellular target for delivery of loaded nanoparticles functionalized with a histone deacetylase inhibitor

Functionalized nanoparticles (NPs) are usually used to enhance cellular penetration for targeted drug delivery that can improve efficacy and reduce side effects. However, it is difficult to exploit intracellular targets for similar delivery applications. Herein we describe the targeted delivery of functionalized NPs by homing in on an intracellular target, histone deacetylases (HDACs). Specifically, a modified poly-lactide-co-glycolideacid (FPLGA) was yielded by conjugation with an HDAC inhibitor. Subsequently, FPLGA was used to prepare functionalized FPLGA NPs. Compared to unmodified NPs, FPLGA NPs were more efficiently uptaken or retained by MCF-7 cells and showed longer retention time intracellular. In vivo fluorescence imaging also revealed that they had a higher accumulation and a slower elimination than unmodified NPs. FPLGA NPs loaded with paclitaxel exhibited superior anticancer efficacy compared with unmodified NPs. These results offer a promising approach for intracellular drug delivery through elevating the concentration of NPs.

Zwitterionic Nanocarrier Surface Chemistry Improves siRNA Tumor Delivery and Silencing Activity Relative to Polyethylene Glycol

Although siRNA-based nanomedicines hold promise for cancer treatment, conventional siRNA-polymer complex (polyplex) nanocarrier systems have poor pharmacokinetics following intravenous delivery, hindering tumor accumulation. Here, we determined the impact of surface chemistry on the in vivo pharmacokinetics and tumor delivery of siRNA polyplexes. A library of diblock polymers was synthesized, all containing the same pH-responsive, endosomolytic polyplex core-forming block but different corona blocks: 5 kDa (benchmark) and 20 kDa linear polyethylene glycol (PEG), 10 kDa and 20 kDa brush-like poly(oligo ethylene glycol), and 10 kDa and 20 kDa zwitterionic phosphorylcholine-based polymers (PMPC). In vitro, it was found that 20 kDa PEG and 20 kDa PMPC had the highest stability in the presence of salt or heparin and were the most effective at blocking protein adsorption. Following intravenous delivery, 20 kDa PEG and PMPC coronas both extended circulation half-lives 5-fold compared to 5 kDa PEG. However, in mouse orthotopic xenograft tumors, zwitterionic PMPC-based polyplexes showed highest in vivo luciferase silencing (>75% knockdown for 10 days with single IV 1 mg/kg dose) and 3-fold higher average tumor cell uptake than 5 kDa PEG polyplexes (20 kDa PEG polyplexes were only 2-fold higher than 5 kDa PEG). These results show that high molecular weight zwitterionic polyplex coronas significantly enhance siRNA polyplex pharmacokinetics without sacrificing polyplex uptake and bioactivity within tumors when compared to traditional PEG architectures.

Mechanisms that determine nanocarrier targeting to healthy versus inflamed lung regions

Inflamed organs display marked spatial heterogeneity of inflammation, with patches of inflamed tissue adjacent to healthy tissue. To investigate how nanocarriers (NCs) distribute between such patches, we created a mouse model that recapitulates the spatial heterogeneity of the inflammatory lung disease ARDS. NCs targeting the epitope PECAM strongly accumulated in the lungs, but were shunted away from inflamed lung regions due to hypoxic vasoconstriction (HVC). In contrast, ICAM-targeted NCs, which had lower whole-lung uptake than PECAM/NCs in inflamed lungs, displayed markedly higher NC levels in inflamed regions than PECAM/NCs, due to increased regional ICAM. Regional HVC, epitope expression, and capillary leak were sufficient to predict intra-organ of distribution of NCs, antibodies, and drugs. Importantly, these effects were not observable with traditional spatially-uniform models of ARDS, nor when examining only whole-organ uptake. This study underscores how examining NCs' intra-organ distribution in spatially heterogeneous animal models can guide rational NC design.

Luminescent iridium(iii) complexes as COX-2-specific imaging agents in cancer cells

This is the first application of iridium(iii) complexes as imaging agents for COX-2.

Kinsenoside screening with a microfluidic chip attenuates gouty arthritis through inactivating NF-κB signaling in macrophages and protecting endothelial cells

Gouty arthritis is a rheumatic disease that is characterized by the deposition of monosodium urate (MSU) in synovial joints cause by the increased serum hyperuricemia. This study used a three-dimensional (3D) flowing microfluidic chip to screen the effective candidate against MSU-stimulated human umbilical vein endothelial cell (HUVEC) damage, and found kinsenoside (Kin) to be the leading active component of Anoectochilus roxburghi, one of the Chinese medicinal plant widely used in the treatment of gouty arthritis clinically. Cell viability and apoptosis of HUVECs were evaluated, indicating that direct Kin stimulation and conditioned medium (CM) from Kin-treated macrophages both negatively modulated with MSU crystals. Additionally, Kin was capable of attenuating MSU-induced activation of nuclear factor-κB/mitogen-activated protein kinase (NF-κB/MAPK) signaling, targeting IκB kinase-α (IKKα) and IKKβ kinases of macrophages and influencing the expressions of NF-κB downstream cytokines and subsequent HUVEC bioactivity. Inflammasome NLR pyrin domain-containing 3 (NALP3) and toll-like receptor 2 (TLR2) were also inhibited after Kin treatment. Also, Kin downregulated CD14-mediated MSU crystals uptake in macrophages. In vivo study with MSU-injected ankle joints further revealed the significant suppression of inflammatory infiltration and endothelia impairment coupled with alleviation of ankle swelling and nociceptive response via Kin treatments. Taken together, these data implicated that Kin was the most effective candidate from Anoectochilus roxburghi to treat gouty arthritis clinically.