Perfluorocarbon Nanoparticles Research Articles

Perfluorocarbons: A perspective of theranostic applications and challenges.

Perfluorocarbon (PFC) are biocompatible compounds, chemically and biologically inert, and lacks toxicity as oxygen carriers. PFCs nanoemulsions and nanoparticles (NPs) are highly used in diagnostic imaging and enable novel imaging technology in clinical imaging modalities to notice and image pathological and physiological alterations. Therapeutics with PFCs such as the innovative approach to preventing thrombus formation, PFC nanodroplets utilized in ultrasonic medication delivery in arthritis, or PFC-based NPs such as Perfluortributylamine (PFTBA), Pentafluorophenyl (PFP), Perfluorohexan (PFH), Perfluorooctyl bromide (PFOB), and others, recently become renowned for oxygenating tumors and enhancing the effects of anticancer treatments as oxygen carriers for tumor hypoxia. In this review, we will discuss the recent advancements that have been made in PFC's applications in theranostic (therapeutics and diagnostics) as well as assess the benefits and drawbacks of these applications.

Redox modulation with a perfluorocarbon nanoparticle to reverse Treg-mediated immunosuppression and enhance anti-tumor immunity.

Tumor hypoxia and high glutathione (GSH) expression promote regulatory T cell (Treg) infiltration and maintain its immunosuppressive function, which significantly reduces the response rate of cancer immunotherapy. Here, we developed an immunomodulatory nano-formulation (FEM@PFC) to reverse Treg-mediated immunosuppression by redox regulation in the tumor microenvironment (TME). Oxygen carried in perfluorocarbon (PFC) was delivered to the TME, thus relieving the hypoxic condition and inhibiting Treg infiltration. More importantly, GSH depletion by the prodrug efficiently restricted the Foxp3 expression and immunosuppressive function of Tregs, thus breaking the shackles of tumor immunosuppression. Additionally, the supplement of oxygen cooperated with the consumption of GSH to enhance the irradiation-induced immunogenic cell death and subsequent dendritic cell (DC) maturation, thereby efficiently promoting the activation of effector T cells and restricting the immunosuppression of Tregs. Collectively, the FEM@PFC nano-formulation reverses Treg-mediated immunosuppression and regulates the redox balance in the TME to boost anti-tumor immunity and prolong the survival of tumor-bearing mice, which provides a new immunoregulatory strategy from the perspective of redox modulation.

Modified Nanoparticles for the Diagnosis and Treatment of Ischemic Stroke

Stroke is a disease that will affect both physical health and mental health of people. Scientists are developing different methods to detect and cure this disease. Nanotechnology has achieved successful results in diagnosis as well as treatment of ischemic stroke. Stroke will cause blood-brain barrier dysfunction which provides chances for detection and treatment to process. Researchers have developed and evaluated a variety of nanoparticles in vivo or in vitro, including gold nanoparticles, perfluorocarbon nanoparticles, PLGA nanoparticles and iron oxide nanoparticles. These nanoparticles are being modified and achieve good results in diagnosis including magnetic resonance imaging, microwave imaging and fluorescence imaging, and treatment including thrombolysis and stem cell transplantation. Nanotechnology has several benefits such as tiny size and ease to modified which will fasten future development in stroke detection and treatment. This review paper will outline several different modification methods of various nanoparticles in laboratory.

Simultaneous Inhibition of Thrombosis and Inflammation Is Beneficial in Treating Acute Myocardial Infarction.

Myocardial ischemia reperfusion injury (IRI) in acute coronary syndromes is a condition in which ischemic/hypoxic injury to cells subtended by the occluded vessel continues despite successful resolution of the thrombotic obstruction. For decades, most efforts to attenuate IRI have focused on interdicting singular molecular targets or pathways, but none have successfully transitioned to clinical use. In this work, we investigate a nanoparticle-based therapeutic strategy for profound but local thrombin inhibition that may simultaneously mitigate both thrombosis and inflammatory signaling pathways to limit myocardial IRI. Perfluorocarbon nanoparticles (PFC NP) were covalently coupled with an irreversible thrombin inhibitor, PPACK (Phe[D]-Pro-Arg-Chloromethylketone), and delivered intravenously to animals in a single dose prior to ischemia reperfusion injury. Fluorescent microscopy of tissue sections and 19F magnetic resonance images of whole hearts ex vivo demonstrated abundant delivery of PFC NP to the area at risk. Echocardiography at 24 h after reperfusion demonstrated preserved ventricular structure and improved function. Treatment reduced thrombin deposition, suppressed endothelial activation, inhibited inflammasome signaling pathways, and limited microvascular injury and vascular pruning in infarct border zones. Accordingly, thrombin inhibition with an extraordinarily potent but locally acting agent suggested a critical role for thrombin and a promising therapeutic strategy in cardiac IRI.

Rapamycin Perfluorocarbon Nanoparticle Mitigates Cisplatin-Induced Acute Kidney Injury.

For nearly five decades, cisplatin has played an important role as a standard chemotherapeutic agent and been prescribed to 10-20% of all cancer patients. Although nephrotoxicity associated with platinum-based agents is well recognized, treatment of cisplatin-induced acute kidney injury is mainly supportive and no specific mechanism-based prophylactic approach is available to date. Here, we postulated that systemically delivered rapamycin perfluorocarbon nanoparticles (PFC NP) could reach the injured kidneys at sufficient and sustained concentrations to mitigate cisplatin-induced acute kidney injury and preserve renal function. Using fluorescence microscopic imaging and fluorine magnetic resonance imaging/spectroscopy, we illustrated that rapamycin-loaded PFC NP permeated and were retained in injured kidneys. Histologic evaluation and blood urea nitrogen (BUN) confirmed that renal structure and function were preserved 48 h after cisplatin injury. Similarly, weight loss was slowed down. Using western blotting and immunofluorescence staining, mechanistic studies revealed that rapamycin PFC NP significantly enhanced autophagy in the kidney, reduced the expression of intercellular adhesion molecule 1 (ICAM-1) and vascular cell adhesion molecule 1 (VCAM-1), as well as decreased the expression of the apoptotic protein Bax, all of which contributed to the suppression of apoptosis that was confirmed with TUNEL staining. In summary, the delivery of an approved agent such as rapamycin in a PFC NP format enhances local delivery and offers a novel mechanism-based prophylactic therapy for cisplatin-induced acute kidney injury.

Alveolar Macrophages-Mediated Translocation of Intratracheally Delivered Perfluorocarbon Nanoparticles to Achieve Lung Cancer 19F-MR Imaging.

Recent advances in intratracheal delivery strategies have sparked considerable biomedical interest in developing this promising approach for lung cancer diagnosis and treatment. However, there are very few relevant studies on the behavior and mechanism of imaging nanoparticles (NPs) after intratracheal delivery. Here, we found that nanosized perfluoro-15-crown-5-ether (PFCE NPs, ∼200 nm) exhibite significant 19F-MRI signal-to-noise ratio (SNR) enhancement than perfluorooctyl bromide (PFOB NPs) up to day 7 after intratracheal delivery. Alveolar macrophages (AMs) engulf PFCE NPs, become PFCE NPs-laden AMs, and then migrate into the tumor margin, resulting in increased tumor PFCE concentration and 19F-MRI signals. AMs-mediated translocation of PFCE NPs to lung draning lymph nodes (dLNs) decreases the background PFCE concentration. Our results shed light on the dynamic AMs-mediated translocation of intratracheally delivered PFC NPs for effective lung tumor visualization and reveal a pathway to develop and promote the clinical translation of an intratracheal delivery-based imaging strategy.

Novel combination strategy of high intensity focused ultrasound (HIFU) and checkpoint blockade boosted by bioinspired and oxygen-supplied nanoprobe for multimodal imaging-guided cancer therapy

BackgroundHigh-intensity focused ultrasound (HIFU) has shown considerable promise in treating solid tumors, but its ultrasonic energy is easily attenuated, resulting in insufficient energy accumulation in the target area. Moreover, HIFU...

Fluorinated Hyaluronic Acid Encapsulated Perfluorocarbon Nanoparticles as Tumor-Targeted Oxygen Carriers to Enhance Radiotherapy.

The efficacy of radiotherapy is significantly constricted by tumor hypoxia. To overcome this obstacle, one promising approach is to use the perfluorocarbon-based O2 carriers combined with hyperoxic respiration to relieve tumor hypoxia. However, this passively transported oxygen carrier during hyperoxic respiration is prone to cause systemic oxidative stress and toxicity, which further limits its clinical application. Herein, we fabricate O2@PFC@FHA NPs for safe and specific oxygen delivery into tumors by using the fluorinated hyaluronic acid to encapsulate O2-saturated perfluorocarbon. Due to the interaction between HA and CD44 receptors, more FHA@PFC NPs accumulated in the tumor and the O2@PFC@FHA NPs significantly relieved tumor hypoxia. Notably, RT plus O2@PFC@FHA NPs resulted in almost threefold therapeutic improvement compared with RT without obvious systemic toxicity. Therefore, the O2@FHA@PFC NPs may have great potential to enhance the therapeutic efficacy of radiotherapy in the clinic.

Safety Profile of Rapamycin Perfluorocarbon Nanoparticles for Preventing Cisplatin-Induced Kidney Injury.

Cancer treatment-induced toxicities may restrict maximal effective dosing for treatment and cancer survivors’ quality of life. It is critical to develop novel strategies that mitigate treatment-induced toxicity without affecting the efficacy of anti-cancer therapies. Rapamycin is a macrolide with anti-cancer properties, but its clinical application has been hindered, partly by unfavorable bioavailability, pharmacokinetics, and side effects. As a result, significant efforts have been undertaken to develop a variety of nano-delivery systems for the effective and safe administration of rapamycin. While the efficacy of nanostructures carrying rapamycin has been studied intensively, the pharmacokinetics, biodistribution, and safety remain to be investigated. In this study, we demonstrate the potential for rapamycin perfluorocarbon (PFC) nanoparticles to mitigate cisplatin-induced acute kidney injury with a single preventative dose. Evaluations of pharmacokinetics and biodistribution suggest that the PFC nanoparticle delivery system improves rapamycin pharmacokinetics. The safety of rapamycin PFC nanoparticles was shown both in vitro and in vivo. After a single dose, no disturbance was observed in blood tests or cardiac functional evaluations. Repeated dosing of rapamycin PFC nanoparticles did not affect overall spleen T cell proliferation and responses to stimulation, although it significantly decreased the number of Foxp3+CD4+ T cells and NK1.1+ cells were observed.

Perfluorocarbons Therapeutics in Modern Cancer Nanotechnology for Hypoxiainduced Anti-tumor Therapy.

With an estimated failure rate of about 90%, immunotherapies that are intended for the treatment of solid tumors have caused an anomalous rise in the mortality rate over the past decades. It is apparent that resistance towards such therapies primarily occurs due to elevated levels of HIF-1 (Hypoxia-induced factor) in tumor cells, which are caused by disrupted microcirculation and diffusion mechanisms. With the advent of nanotechnology, several innovative advances were brought to the fore; and, one such promising direction is the use of perfluorocarbon nanoparticles in the management of solid tumors. Perfluorocarbon nanoparticles enhance the response of hypoxia-based agents (HBAs) within the tumor cells and have been found to augment the entry of HBAs into the tumor micro-environment. The heightened penetration of HBAs causes chronic hypoxia, thus aiding in the process of cell quiescence. In addition, this technology has also been applied in photodynamic therapy, where oxygen self-enriched photosensitizers loaded perfluorocarbon nanoparticles are employed. The resulting processes initiate a cascade, depleting tumour oxygen and turning it into a reactive oxygen species eventually to destroy the tumour cell. This review elaborates on the multiple applications of nanotechnology based perfluorocarbon formulations that are being currently employed in the treatment of tumour hypoxia.

Abstract 13192: Local Delivery of Thrombin Inhibiting Nanoparticles Preserves Cardiac Function and Modulates NLRP3 Inflammasome Processes in Acute Myocardial Infarction

Introduction: The role of thrombin in acute myocardial infarction (AMI) has been well described, with recent attention having turned to its effect on NLRP3 inflammasome activation and the role that plays in the pathogenesis of AMI. Perfluorocarbon nanoparticles conjugated to phenylalanine-proline-arginine-chloromethylketone (PPACK NPs) are extremely potent local inhibitors of thrombin, but their role in therapy for AMI remains unclear. We hypothesize that pre-treatment with sustained locally acting PPACK NPs preserves cardiac function by attenuating thrombin-induced inflammatory processes, including those driven by the NLRP3 inflammasome. Methods: Nine mice underwent left anterior descending (LAD) occlusion for 45 minutes. At 30 minutes before LAD occlusion, mice were injected with PPACK (n=5) or control NPs (n=4). 24 hours post-reperfusion, hearts were excised and perfused. LAD was re-occluded and Lectin-488 perfused through the excised heart. Echo was performed pre- and post-reperfusion to assess cardiac function. Hearts were sectioned for follow up histological and protein analysis. Results: PPACK NP treated mice exhibited evidence of preserved cardiac function 24 hours post-reperfusion (Figure 1, A-B), reduced nuclear translocation of p65 in infarcted myocardium (Figure 1, C-D), and reduced inflammatory markers with better vessel preservation in the area adjacent to uninjured myocardium (Figure 1, E-F). The PPACK NP group also demonstrated suppression of NLRP3 inflammasome activation (Figure 2). Conclusion: Local inhibition of thrombin with anti-inflammatory PPACK NPs preserves cardiac function when administered systemically as pre-treatment.

Sustained local inhibition of thrombin preserves renal microarchitecture and function after onset of acute kidney injury

Acute kidney injury (AKI) management remains mainly supportive as no specific therapeutic agents directed at singular signaling pathways have succeeded in clinical trials. Here, we report that inhibition of thrombin-driven clotting and inflammatory signaling with use of locally-acting thrombin-targeted perfluorocarbon nanoparticles (PFC NP) protects renal vasculature and broadly modulates diverse inflammatory processes that cause renal ischemia reperfusion injury. Each PFC NP was complexed with ~13,650 copies of the direct thrombin inhibitor, PPACK (proline-phenylalanine-arginine-chloromethyl-ketone). Mice treated after the onset of AKI with PPACK PFC NP exhibited downregulated VCAM-1, ICAM-1, PGD2 prostanoid, M-CSF, IL-6, and mast cell infiltrates. Microvascular architecture, tubular basement membranes, and brush border components were better preserved. Non-reperfusion was reduced as indicated by reduced red blood cell trapping and non-heme iron. Kidney function and tubular necrosis improved at 24 hours versus the untreated control group, suggesting a benefit for dual inhibition of thrombosis and inflammation by PPACK PFC NP.

Local direct thrombin inhibition preserves renal function by mitigating vascular damage and modulating pathophysiologic processes after onset of acute kidney injury

Objective : To determine if thrombin-inhibiting nanoparticles preserve renal function when administered after onset of ischemia-reperfusion acute kidney injury (AKI), and to determine physiologic mechanisms by which this occurs. Hypothesis AKI therapy remains mainly supportive, as recent clinical trials of promising therapeutic agents have failed to preserve renal function. It has been previously shown that delivery of direct thrombin inhibiting nanoparticles prior to onset of AKI in mice has successfully preserved renal function. We hypothesized that inhibition of thrombin clotting and inflammatory signaling with the use of a sustained locally acting nanoparticle formulation might both preserve renal vasculature and broadly modulate pathophysiologic processes that contribute to renal ischemia reperfusion injury even after its onset. Methods C57BL/6 mice underwent bilateral warm ischemia for 17 minutes at 37°C followed by reperfusion. Two hours after reperfusion, mice were injected with either direct thrombin-inhibiting (n=10) or control (n=12) perfluorocarbon nanoparticles (PFC NP). The treatment PFC NP contained ~ 13650 copies per nanoparticle of the direct thrombin inhibitor, PPACK (Proline-Phenylalanine-Arginine-Chloromethyl-Ketone). After 24 hours, blood and kidneys were collected for evaluation of BUN, inflammatory eicosanoids and cytokines, histological analysis of vascular damage, endothelial activation, and cellular infiltrates. Results : Mice treated after AKI with direct thrombin-inhibiting PPACK NP exhibited significantly improved kidney function at 24 hours versus the control group (BUN: 62.10±8.71mg/dL vs 110.96 ±6.21mg/dL, p=0.0002). Vascular integrity was preserved as evidenced by increased expression of CD31 in both cortex (4.28±0.62% vs 1.75±0.34%, p=0.0018) and medulla (3.24±0.38% vs 1.91±0.29%; p=0.0073). Additionally, the PPACK NP group demonstrated significantly less acute tubular necrosis (ATN), further mitigating vascular damage (ATN: 24.44±1.76% vs 37.00±4.96%, p=0.035). Treatment reduced red blood cell trapping and subsequent iron accumulation in both cortex (3.37±0.50% vs 5.34±0.42%, p=0.0083) and medulla (0.50%±0.10% vs 1.01%±0.12%, p=0.006). Inflammatory markers were also reduced in the PPACK NP group, including endothelial VCAM-1 (positive area in medulla 0.49±0.12% vs 1.41±0.60%, p=0.0073), ICAM-1 (positive area in medulla 3.07±0.51% vs 4.46±0.35%, p=0.030). and serum M-CSF and IL-6. Mast cell infiltration and prostaglandin D2 (PGD2) were also decreased. Conclusion Nanoparticle delivery of local thrombin inhibitors that have a known minimal effect on systemic clotting parameters successfully protects renal function by preserving renal vasculature, reducing ATN and iron accumulation, and broadly attenuating thrombin-induced inflammatory mechanisms even when delivered after onset of AKI.

Repetitive optical coherence elastography measurements with blinking nanobombs.

Excitation of dye-loaded perfluorocarbon nanoparticles (nanobombs) can generate highly localized axially propagating longitudinal shear waves (LSW) that can be used to quantify tissue mechanical properties without transversal scanning of the imaging beam. In this study, we used repetitive excitations of dodecafluoropentane (C5) and tetradecafluorohexane (C6) nanobombs by a nanosecond-pulsed laser to produce multiple LSWs from a single spot in a phantom. A 1.5 MHz Fourier-domain mode-locked laser in combination with a phase correction algorithm was used to perform elastography. Multiple nanobomb activations were also monitored by detecting photoacoustic signals. Our results demonstrate that C6 nanobombs can be used for repetitive generation of LSW from a single spot for the purpose of material elasticity assessment. This study opens new avenues for continuous quantification of tissue mechanical properties using single delivery of the nanoparticles.

Abstract 2784: Intratracheally delivered perflurocarbon nanoparticles to enhance radiotherapy against lung cancer

Abstract Radiotherapy (RT) is a major treatment modality for lung cancer. Despite of technological advances, the five-year survival rate remains low. There is an urgent need of new and effective approaches that can selectively sensitize lung cancer cells to radiation. In this proof-of-concept study, we tested whether intratracheally(IT) delivered perfluorocarbon nanoparticles (PFC NPs) can enhance radiotherapy against lung cancer. We hypothesize that the approach can capitalize on the oxygen-loading capacity of PFC NPs and solve the unfavorable delivery problem associated with systemically injected PFC NPs. Therapy studies were performed in mice bearing subcutaneously inoculated H460 tumors and in orthotopicVX2 tumor models established on New Zealand white rabbits. PET/CT, 19F-MRI, and DCE-MRI were employed to assess PFC NPs delivery and treatment outcomes. 1H-MRS was performed on tumors from different treatment groups and the results were compared with in vivo imaging. For both tumor models, animals were divided into four groups (n=3 for rabbits and 5 for mice): (1) control; (2) PFC NPs only; (3) radiotherapy only; and (4) RT+PFC NPs group. Tumor tissues were subjected to pathology analysis and the results were compared with imaging data. Urine samples were collected and analyzed by UPLC-Q-TOF-MS/MS to assess metastasis. Our results showed that combining IT delivered PFC NPs and radiotherapy led to significantly enhanced tumor growth inhibition. Specifically, 19F-MRI confirmed that PFC NPs can deliver O2 to tumors and increase the mean pO2. DCE-MRI showed distinct tumor blood perfusion behaviors in the RT+PFC NPs group (P<0.05).We also compared the 18F-FDG accumulation in lesions in the early dynamic perfusion phase with the standard static metabolic phase by analyzing the peak value of the SUV mean, time to peak value, and the rate of the SUVmean increase. We found significant difference between the two phases in the RT+PFCNPs group. 1H-MRS found a decreased Cho/Cr ratio in animals treated by RT+PFC, suggesting that the combination treatment improved tumor suppression. Meanwhile, urine glutamine content is elevated in the RT+PFCNPs group, indicating a tendency to return to normal after treatment. Overall, our studies suggest the potential of IT delivered PFCNPs to enhance lung cancer radiotherapy. The delivery of the particles can be image-guided for efficient and site-specific radiosensitization. The approach holds great promise in clinical translation. Citation Format: Lina Wu, Jin Xie. Intratracheally delivered perflurocarbon nanoparticles to enhance radiotherapy against lung cancer [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 2784.

Targeted Myoglobin Delivery as a Strategy for Enhancing the Sensitivity of Hypoxic Cancer Cells to Radiation.

SummaryThe effectiveness of cancer radiotherapy is frequently hindered by the hypoxia of the tumor microenvironment. Direct delivery of oxygen to hypoxic tumor tissues is an attractive strategy to overcome this hypoxia-associated radioresistance. Herein, we report the generation of submicron-sized particles comprising myoglobin fused to the crystal-forming domain of Cry3Aa protein for the targeted delivery of oxygen to cancer cells. We demonstrate that myoglobin-containing particles were successfully produced in Bacillus thuringiensis with the assistance of the Cry3Aa domain I. Furthermore, these particles could be genetically modified to incorporate the cell penetrating peptide TAT and cell targeting peptide A549.1, resulting in particles that exhibited improved cellular uptake and targeting toward A549 cells. Notably, these myoglobin-containing particles increased the intracellular oxygen levels of A549 cells and thereby sensitized them to radiation. These findings suggest that the targeted delivery of O2-bound myoglobin could be an effective approach to enhance the efficacy of radiotherapy.

Enhanced antitumor efficacy in colon cancer using EGF functionalized PLGA nanoparticles loaded with 5-Fluorouracil and perfluorocarbon

BackgroundTumor recurrence and metastasis occur at a high rate in patients with colon cancer. Identification of effective strategies for the treatment of colon cancer is critical. Recently, poly (lactic-co-glycolic acid) (PLGA) has been shown to have potential as a broad therapeutic drug delivery system. We designed a dual-loaded nanoparticle drug delivery system to overcome the limitations of chemotherapeutic drugs used to treat colon cancer.MethodsWe developed epidermal growth factor (EGF) functionalized PLGA nanoparticles (NPs) co-loaded with 5-fluorouracil (5Fu) and perfluorocarbon (PFC) (EGF-PLGA@5Fu/PFC) for targeted treatment of colon cancer. CCK-8 assay, Hoechst33342 staining and flow cytometry were performed to investigate the functions of EGF-PLGA@5Fu/PFC NPs in SW620 cells. Beside, animal experiment, histological analysis and immunofluorescence staining were adopted to further confirm the role of EGF-PLGA@5Fu/PFC NPs in vivo.ResultsThe findings showed that EGF-PLGA@5Fu /PFC NPs had an average size 200 nm and a 5Fu-loading efficiency of 7.29%. Furthermore, in vitro release was pH-sensitive. Targeted EGF-PLGA@5Fu/PFC NPs exhibited higher cellular uptake than non-targeted NPs into colon cancer cells. In addition, EGF-PLGA@5Fu/PFC NPs suppressed cell viability and induced apoptosis in SW620 cells to a greater extent than non-targeted NPs. In tumor xenografted mice, EGF-PLGA@5Fu/PFC NPs suppressed tumor growth more effectively than 5Fu, PLGA@5Fu or PLGA@5Fu/PFC NPs. Histopathological analysis further demonstrated that EGF-targeted NPs inhibited tumor growth to a greater extent than non-targeted or non-NP treatments. The improved therapeutic outcomes observed in this study were due to relief of tumor hypoxia by transport of oxygen by PFC to the tumors.ConclusionWe constructed a biocompatible nanodrug delivery system based on functionalized nanoparticles that provided a novel strategy for selective delivery of chemotherapy drugs to tumors.

Nanotherapy delivery of c-myc inhibitor targets Protumor Macrophages and preserves Antitumor Macrophages in Breast Cancer.

Tumor-associated macrophages (TAMs) enhance tumor growth in mice and are correlated with a worse prognosis for breast cancer patients. While early therapies sought to deplete all macrophages, current therapeutics aim to reprogram pro-tumor macrophages (M2) and preserve those necessary for anti-tumor immune responses (M1). Recent studies have shown that c-MYC (MYC) is induced in M2 macrophages in vitro and in vivo where it regulates the expression of tumor-promoting genes. In a myeloid lineage MYC KO mouse model, MYC had important roles in macrophage maturation and function leading to reduced tumor growth. We therefore hypothesized that targeted delivery of a MYC inhibitor to established M2 TAMs could reduce polarization toward an M2 phenotype in breast cancer models.Methods: In this study, we developed a MYC inhibitor prodrug (MI3-PD) for encapsulation within perfluorocarbon nanoparticles, which can deliver drugs directly to the cytosol of the target cell through a phagocytosis independent mechanism. We have previously shown that M2-like TAMs express significant levels of the vitronectin receptor, integrin β3, and in vivo targeting and therapeutic potential was evaluated using αvβ3 integrin targeted rhodamine-labeled nanoparticles (NP) or integrin αvβ3-MI3-PD nanoparticles.Results: We observed that rhodamine, delivered by αvβ3-rhodamine NP, was incorporated into M2 tumor promoting macrophages through both phagocytosis-independent and dependent mechanisms, while NP uptake in tumor suppressing M1 macrophages was almost exclusively through phagocytosis. In a mouse model of breast cancer (4T1-GFP-FL), M2-like TAMs were significantly reduced with αvβ3-MI3-PD NP treatment. To validate this effect was independent of drug delivery to tumor cells and was specific to the MYC inhibitor, mice with integrin β3 knock out tumors (PyMT-Bo1 β3KO) were treated with αvβ3-NP or αvβ3-MI3-PD NP. M2 macrophages were significantly reduced with αvβ3-MI3-PD nanoparticle therapy but not αvβ3-NP treatment.Conclusion: These data suggest αvβ3-NP-mediated drug delivery of a c-MYC inhibitor can reduce protumor M2-like macrophages while preserving antitumor M1-like macrophages in breast cancer.

Formulation and Characterization of Antithrombin Perfluorocarbon Nanoparticles.

Thrombin, a major protein involved in the clotting cascade by the conversion of inactive fibrinogen to fibrin, plays a crucial role in the development of thrombosis. Antithrombin nanoparticles enable site-specific anticoagulation without increasing bleeding risk. Here we outline the process of making and the characterization of bivalirudin and D-phenylalanyl-L-prolyl-L-arginyl-chloromethyl ketone (PPACK) nanoparticles. Additionally, the characterization of these nanoparticles, including particle size, zeta potential, and quantification of PPACK/bivalirudin loading, is also described.

P702Anti-thrombin nanoparticles for reduce vascular damage and promote functional recovery in acute ischemic kidney injury well after reperfusion

Abstract Introduction We have shown previously that pretreatment of acute ischemic kidney injury (AKI) in mice prior to reperfusion with anti-thrombin perfluorocarbon nanoparticles (PFC NP) limits damage to endothelium and hastens functional recovery. However, whether such treatments are effective after AKI is established is not known. We hypothesized that thrombin would continue to exert deleterious clotting and molecular signaling effects in AKI well after reperfusion that would respond to sustained local inhibition with long acting anti-thrombin nanoparticles. Methods 23 C57Bl6 mice underwent bilateral kidney ischemia for 17 min, followed by 2 hours reperfusion and i.v. injection of anti-thrombin PPACK (D-phenylalanyl-L-prolyl-L-arginine chloromethyl ketone)-conjugated PFC NP (∼ 13,000 PPACK per PFC NP), or plain PFC NP (control: no drug). At 24 hours BUN was measured, and mice were euthanized for kidney histological assessment (H&E), protein expression (western blot) and eicosanoid mediators of inflammation (LC-MS/MS: AB SCIEX 5500 QTRAP). Results BUN at 24 hours after AKI was 63.29±9.09 vs 110.96±6.21 (P<0.002), for treated versus untreated mice, respectively, a 43% improvement. Western blots (Figure) indicated 40% reduction of canonical NF-kB signaling pathway protein p65 (p<0.01) and 2.2 fold increases in Bcl-xL: Bax ratio (P<0.01). Vascular damage, as indicated by glomerular and mesangial hemorrhage (Figure), was reduced, as was tubular cell swelling and edema. Levels of inflammatory procoagulant eicosanoids (e.g., PGE1, TBX2, PGA2, 15-HETE, 5-HETE, etc.) generally were higher in renal medulla than in cortex, and were suppressed by PPACK PFC NP. Discussion Continued inhibition of thrombin in AKI with locally-acting PPACK PFC NP preserved vascular integrity, limited renal hemorrhage, mitigated inflammation and tubular cell death, and accelerated functional recovery even when administered 2 hours after reperfusion. Because these PPACK PFC NP do not prolong bleeding times or coagulation parameters beyond ∼30–60 min after injection, yet maintain prolonged local surveillance against activated thrombin, they represent a potentially useful therapeutic strategy for established AKI after an ischemic insult. Acknowledgement/Funding DK102691