Resiquimod-loaded cationic liposomes cure mice with peritoneal carcinomatosis and induce specific anti-tumor immunity.

Peritoneal carcinomatosis (PC) is characterized by a high recurrence rate and mortality following cytoreductive surgery and hyperthermic intraperitoneal chemotherapy (HIPEC), primarily due to incomplete cancer elimination. To enhance the standard of care for PC, we developed two cationic liposomal formulations aimed at localizing a toll-like receptor agonist, resiquimod (R848), in the peritoneal cavity to activate the immune system locally to specifically eradicate residual tumor cells. These formulations effectively extended R848 retention in the peritoneum by >10-fold, resulting in up to a 2-fold increase in interferon α (IFN-α) induction in the peritoneal fluid, without increasing the plasma levels. In a CT26 colon cancer model with peritoneal metastases, these liposomal R848 formulations, when combined with oxaliplatin (OXA)-an agent used in HIPEC that induces immunogenic cell death-increased tumor infiltration of effector immune cells, including DCs, CD4, and CD8 T cells. This led to the complete elimination of PC in 60-70% of the mice, while the control mice reached humane endpoints by 30 days. The cured mice developed specific antitumor immunity, as re-challenging them with the same tumor cells did not result in tumor establishment. However, inoculation with a different tumor line led to tumor development. Additionally, exposing CT26 tumor antigens to the splenocytes isolated from the cured mice induced the expansion of CD4 and CD8 T cells and the release of IFN-γ, demonstrating long-term immune memory to the specific tumor. The anti-tumor efficacy of these liposomal R848 formulations was mediated via CD8 T cells with different levels of involvement of CD4 and B cells, and the combination with an anti-PD-1 antibody achieved a cure rate of 90%.

Intranasal delivery of low-dose anti-CD124 antibody enhances treatment of chronic rhinosinusitis with nasal polyps.

Frequent injections of anti-CD124 monoclonal antibody (αCD124) over long periods of time are used to treat chronic rhinosinusitis with nasal polyps (CRSwNP). Needle-free, intranasal administration (i.n.) of αCD124 is expected to provide advantages of localized delivery, improved efficacy, and enhanced medication adherence. However, delivery barriers such as the mucus and epithelium in the nasal tissue impede penetration of αCD124. Herein, two novel protamine nanoconstructs: allyl glycidyl ether conjugated protamine (Nano-P) and polyamidoamine-linked protamine (Dendri-P) were synthesized and showed enhanced αCD124 penetration through multiple epithelial layers compared to protamine in mice. αCD124 was mixed with Nano-P or Dendri-P and then intranasally delivered for the treatment of severe CRSwNP in mice. Micro-CT and pathological changes in nasal turbinates showed that these two nano-formulations achieved ∼50 % and ∼40 % reductions in nasal polypoid lesions and eosinophil count, respectively. Both nano-formulations provided enhanced efficacy in suppressing nasal and systemic Immunoglobulin E (IgE) and nasal type 2 inflammatory biomarkers, such as interleukin 13 (IL-13) and IL-25. These effects were superior to those in the protamine formulation group and subcutaneous (s.c.) αCD124 given at a 12.5-fold higher dose. Intranasal delivery of protamine, Nano-P, or Dendri-P did not induce any measurable toxicities in mice.

Protamine-mediated efficient transcellular and transmucosal delivery of proteins.

Proteins and peptides often require frequent needle-based administrations. Here, we report a non-parenteral delivery method for proteins through physical mixing with protamine, an FDA-approved peptide. Protamine was shown to promote tubulation and rearrangement of cellular actin, leading to enhanced intracellular delivery of proteins compared to poly(arginine)8 (R8). While the R8-mediated delivery resulted in significant lysosomal accumulation of the cargo, protamine directed the proteins to the nuclei with little lysosomal uptake. Intranasal delivery of insulin mixed with protamine effectively reduced blood glucose levels in diabetic mice 0.5 h after administration and the effect lasted for ∼6 h, comparable to subcutaneously injected insulin at the same dose. In mice, protamine was shown to overcome mucosal and epithelial barriers and modulate adherens junctions, promoting insulin penetration to the lamina propria layer for systemic absorption.

Chemically engineering the drug release rate of a PEG-paclitaxel conjugate using click and steric hindrance chemistries for optimal efficacy.

A small molecule drug with poor aqueous solubility can be conjugated to a hydrophilic polymer like poly(ethylene glycol) (PEG) to form an amphiphilic polymer-drug conjugate that self-assembles to form nanoparticles (NPs) with improved solubility and enhanced efficacy. This strategy has been extensively applied to improve the delivery of several small molecule drugs. However, very few reports have succeeded to tune the rate of drug release from these NPs. To the best of our knowledge, there have been no reports of utilizing click and steric hindrance chemistry to modulate the drug release of self-assembling polymer-drug conjugates. In this study, we utilized click chemistry to conjugate methoxy-PEG (mPEG) to an anti-tumor drug, paclitaxel (PTX). A focused library of PTX-Rx-mPEG (x = 0, 1, 2) conjugates were synthesized with different chemical modalities next to the cleavable ester bond to study the effect of increasing steric hindrance on the self-assembly process and the physicochemical properties of the resulting PTX-NPs. PTX-R0-mPEG had no added steric hindrance (x = 0; minimal), PTX-R1-mPEG consisted of two methyl groups (x = 1: moderate), and PTX-R2-mPEG consisted of a phenyl group (x = 2: significant). Drug release studies showed that PTX-NPs released PTX at a decreased rate with increasing steric hindrance. Pharmacokinetic studies showed that the AUC of released PTX from the moderate-release PTX-R1-NP was approximately 20-, 6-, and 3-fold higher than that from free PTX, PTX-R0-NP and PTX-R2-NP, respectively. As a result, among these different PTX formulations, PTX-R1-NP showed superior efficacy in inducing tumor regression and prolonging the animal survival. The tumors treated with PTX-R1-NP displayed the lowest tumor progression markers (Ki68 and CD31) and the highest apoptotic marker (TUNEL) compared to the others. This work emphasizes the importance of taking a systematic approach in designing self-assembling polymer drug conjugates and highlights the potential of utilizing steric hindrance as a tool to tune the drug release rate from such systems.

Development of a child-friendly oral drug formulation using liposomal multilamellar vesicle technology.

Many medicines are only available in solid dosage forms suitable for adults, and extemporaneous compounding is required to prepare formulations for children. However, this common practice often results in inaccurate dosing and unpleasant taste, reducing the medication adherence. Here, we report the development of a new method to prepare and compound child-friendly oral formulations based on a liposomal multilamellar vesicle (MLV) platform. MLVs composed of a phospholipid (DSPC) and cholesterol (55/45, molar ratio) were prepared using the standard thin film hydration method with 300 mM citric acid (pH 2), followed by an addition of aqueous sodium carbonate to adjust the exterior pH to 8-10 for creating a transmembrane pH gradient. Weak-base drugs, such as chloroquine (CQ) and hydroxychloroquine (HCQ), could be actively and completely loaded into the MLVs at a drug-to-lipid ratio of 15-20 wt%. This technique formulated weak-base drugs from the powder or tablet form into a liquid preparation, and the complete drug encapsulation would prevent contact between the drug molecules and the taste buds. The gradient MLV formulation could be preserved by lyophilization and stored at room temperature for at least 8 weeks. Upon reconstitution with water, the MLV formulation could completely encapsulate CQ at 20 wt%, which was comparable to the freshly prepared MLVs. The CQ-loaded MLV formulation could be stored at 4 °C for 2 weeks without drug leakage. In vitro release studies indicated that MLV could retain CQ in the simulated saliva, but released up to 50% and 30% of the drug in the simulated gastric and intestinal fluids, respectively. The orally delivered MLV-CQ formulation displayed higher CQ absorption in mice, with a 2-fold increase in the area under the curve (AUC) of the plasma profile compared to CQ solution. Our data suggest that the new MLV method could serve as a platform to prepare child-friendly oral formulation for weak-base drugs.

Interplay between the linker and polymer molecular weight of a self-assembling prodrug on the pharmacokinetics and therapeutic efficacy.

Poorly water-soluble small hydrophobic compounds can be conjugated to a hydrophilic polymer such as methoxypolyethylene glycol (mPEG) to form amphiphilic prodrugs that can self-assemble into nanoparticles (NPs) with increased aqueous solubility, prolonged circulation, and improved delivery. There have been numerous reports utilizing this strategy to improve delivery of small molecule drugs, but few reports take systematic, structure-activity relationship (SAR)-based approaches to develop optimal prodrug conjugates. Additionally, it is important to study interplay of different components within the conjugate, such as polymer molecular weight (M.W.) and linker to obtain optimal efficacy and safety. In this study, we developed a click chemistry platform to conjugate mPEG of three different M.W. (low: 550 Da; medium: 2000 Da; high: 5000 Da) to a small molecular anti-tumor drug, gambogic acid (GA) via two different linkers (ester: fast release; amide: slow release) to generate six distinct conjugates. NPs formed from conjugates of mPEG550 displayed significantly higher hemolytic toxicity compared to those with higher M.W. (<10%), regardless of the linker type. Drug release studies showed that NPs with an amide linker displayed insignificant drug release (<0.5% per day) compared to those with an ester linker (1-2% per day). NPs formed with mPEG5000 using an ester linker (5000-E-NP) possessed the optimal balance between prolonged circulation (223-fold higher AUC1-24 h than free GA) and sufficient drug release (1.68 ± 0.13% per day), leading to superior anti-tumor efficacy compared to other formulations, while the corresponding amides (5000-A-NP) displayed the most prolonged circulation but only moderate efficacy likely due to insufficient drug release. Our work highlights the importance of diligently studying SAR on drug conjugates to improve drug delivery and confirms the robustness of using the click platform to generate a conjugate library with chemical diversity.

Simultaneous Chromatographic Quantitation of Drug Substance and Excipients in Nanoformulations Using a Combination of Evaporative Light Scattering and Absorbance Detectors.

Nanomedicines including lipid- and polymer-based nanoparticles and polymer-drug conjugates enable targeted drug delivery for the treatment of numerous diseases. Quantitative analysis of components in nanomedicines is routinely performed to characterize the products to ensure quality and property consistency but has been mainly focused on the active pharmaceutical ingredients (APIs) in academic publications. It has been increasingly recognized that excipients in nanomedicines are critical in determining the product quality, stability, consistency, and safety. APIs are often analyzed by high-performance liquid chromatography (HPLC), and it would be convenient if the same method can be applied to excipients to robustly quantify all components in nanomedicines. Here, we report the development of a HPLC method that combined an evaporative light scattering (ELS) detector with an UV-vis detector to simultaneously analyze drugs and excipients in nanomedicines. This method was tested on diverse nanodrug delivery systems, including a niosomal nanoparticle encapsulating a phytotherapeutic, a liposome encapsulating an immune boosting agent, and a PEGylated peptide. This method can be utilized for a variety of applications, such as monitoring drug loading, studying drug release, and storage stability. The information obtained from the analyses is of importance for nanomedicine formulation development.

Reversal of pancreatic desmoplasia by a tumour stroma-targeted nitric oxide nanogel overcomes TRAIL resistance in pancreatic tumours.

OBJECTIVE: Stromal barriers, such as the abundant desmoplastic stroma that is characteristic of pancreatic ductal adenocarcinoma (PDAC), can block the delivery and decrease the tumour-penetrating ability of therapeutics such as tumour necrosis factor-related apoptosis-inducing ligand (TRAIL), which can selectively induce cancer cell apoptosis. This study aimed to develop a TRAIL-based nanotherapy that not only eliminated the extracellular matrix barrier to increase TRAIL delivery into tumours but also blocked antiapoptotic mechanisms to overcome TRAIL resistance in PDAC. DESIGN: Nitric oxide (NO) plays a role in preventing tissue desmoplasia and could thus be delivered to disrupt the stromal barrier and improve TRAIL delivery in PDAC. We applied an in vitro-in vivo combinatorial phage display technique to identify novel peptide ligands to target the desmoplastic stroma in both murine and human orthotopic PDAC. We then constructed a stroma-targeted nanogel modified with phage display-identified tumour stroma-targeting peptides to co-deliver NO and TRAIL to PDAC and examined the anticancer effect in three-dimensional spheroid cultures in vitro and in orthotopic PDAC models in vivo. RESULTS: The delivery of NO to the PDAC tumour stroma resulted in reprogramming of activated pancreatic stellate cells, alleviation of tumour desmoplasia and downregulation of antiapoptotic BCL-2 protein expression, thereby facilitating tumour penetration by TRAIL and substantially enhancing the antitumour efficacy of TRAIL therapy. CONCLUSION: The co-delivery of TRAIL and NO by a stroma-targeted nanogel that remodels the fibrotic tumour microenvironment and suppresses tumour growth has the potential to be translated into a safe and promising treatment for PDAC.

Liposomal Resiquimod for Enhanced Immunotherapy of Peritoneal Metastases of Colorectal Cancer.

Colorectal cancer with peritoneal metastases is currently treated by cytoreductive surgery and locoregional chemotherapeutics. This standard treatment is associated with high morbidity, mortality, and recurrence rate. To augment the existing therapy, we developed a liposome-based delivery system containing 1,2-stearoyl-3-trimethylammonium-propane chloride (DSTAP), a cationic lipid, to localize a toll-like receptor agonist, resiquimod (R848), in the peritoneal cavity (PerC) for enhancing the immune response against cancer that had spread to the PerC. The liposomes delivered by intraperitoneal injection increased peritoneal retention of R848 by 14-fold while retarding its systemic absorption, leading to a 5-fold decreased peak plasma concentration compared to free R848 in mice. Within the PerC, the DSTAP-liposomes were found in ~40% of the dendritic cells by flow cytometry. DSTAP-R848 significantly upregulated interferon α (IFN-α) in the peritoneal fluid by 2-fold compared to free R848, without increasing the systemic level. Combined with oxaliplatin, a cytotoxic agent inducing immunogenic cell death, DSTAP-R848 effectively inhibited the progression of CT26 murine colorectal tumor in the PerC, while the combination with free R848 only showed a mild effect. Moreover, the combination of oxaliplatin and DSTAP-R848 significantly increased infiltration of CD8+ T cells in the PerC compared to oxaliplatin combined with free R848, indicating enhanced immune response against the tumor. The results suggest that DSTAP-R848 exhibits potential in augmenting existing therapies for treating colorectal cancer with peritoneal metastases via immune activation.

Altering the intra-liver distribution of phospholipid-free small unilamellar vesicles using temperature-dependent size-tunability.

We demonstrated that phospholipid-free small unilamellar vesicles (PFSUVs) composed of TWEEN 80 and cholesterol (25/75, mol%) could be fabricated using a staggered herringbone micromixer with precise controlling of their mean size between 54 nm and 147 nm. Increasing the temperature or decreasing the flow rate led to an increase in the resulting particle diameter. In zebrafish embryos, 120-nm PFSUVs showed 3-fold higher macrophage clearance compared to the 60-nm particles, which exhibited prolonged blood circulation. In mice, the 60-nm particles showed dominant accumulation in the liver hepatocytes (66% hepatocytes positive), while the 120-nm particles were delivered equally to the liver and spleen macrophages. Accordingly, in a murine model of acetaminophen-induced hepatotoxicity the 60-nm particles loaded with chlorpromazine reduced the serum alanine aminotransferase level and liver necrosis 2- to 4-fold more efficiently than their 120-nm counterparts and the free drug, respectively. This work showed that the intra-liver distribution of PFSUVs was largely determined by the size. Most other nanoparticles published to date are predominantly cleared by the liver Kupffer cells. The 60-nm PFSUVs, on the other hand, focused the delivery to the hepatocytes with significant advantages for the therapy of liver diseases.

Lipid-based nanoparticle technologies for liver targeting.

Liver diseases such as hepatitis, cirrhosis, and hepatocellular carcinoma are global health problems accounting for approximately 800 million cases and over 2 million deaths per year worldwide. Major drawbacks of standard pharmacological therapies are the inability to deliver a sufficient concentration of a therapeutic agent to the diseased liver, and nonspecific drug delivery leading to undesirable systemic side effects. Additionally, depending on the specific liver disease, drug delivery to a subset of liver cells is required. In recent years, lipid nanoparticles have been developed to passively and actively target drugs to the liver. The success of this approach has been highlighted by the FDA-approval of the first liver-targeting lipid nanoparticle, ONPATTRO, in 2018 and many other promising candidate technologies are expected to follow. This review summarizes recent developments of various lipid-based liver-targeting technologies, namely solid-lipid nanoparticles, liposomes, niosomes and micelles, and discusses the challenges and future perspectives in this field.

Mechanical stretch induces hair regeneration through the alternative activation of macrophages.

Tissues and cells in organism are continuously exposed to complex mechanical cues from the environment. Mechanical stimulations affect cell proliferation, differentiation, and migration, as well as determining tissue homeostasis and repair. By using a specially designed skin-stretching device, we discover that hair stem cells proliferate in response to stretch and hair regeneration occurs only when applying proper strain for an appropriate duration. A counterbalance between WNT and BMP-2 and the subsequent two-step mechanism are identified through molecular and genetic analyses. Macrophages are first recruited by chemokines produced by stretch and polarized to M2 phenotype. Growth factors such as HGF and IGF-1, released by M2 macrophages, then activate stem cells and facilitate hair regeneration. A hierarchical control system is revealed, from mechanical and chemical signals to cell behaviors and tissue responses, elucidating avenues of regenerative medicine and disease control by demonstrating the potential to manipulate cellular processes through simple mechanical stimulation.

Combined delivery of sorafenib and a MEK inhibitor using CXCR4-targeted nanoparticles reduces hepatic fibrosis and prevents tumor development.

Liver damage and fibrosis are precursors of hepatocellular carcinoma (HCC). In HCC patients, sorafenib-a multikinase inhibitor drug-has been reported to exert anti-fibrotic activity. However, incomplete inhibition of RAF activity by sorafenib may also induce paradoxical activation of the mitogen-activated protein kinase (MAPK) pathway in malignant cells. The consequence of this effect in non-malignant disease (hepatic fibrosis) remains unknown. This study aimed to examine the effects of sorafenib on activated hepatic stellate cells (HSCs), and develop effective therapeutic approaches to treat liver fibrosis and prevent cancer development. Methods: We first examined the effects of sorafenib in combination with MEK inhibitors on fibrosis pathogenesis in vitro and in vivo. To improve the bioavailability and absorption by activated HSCs, we developed CXCR4-targeted nanoparticles (NPs) to co-deliver sorafenib and a MEK inhibitor to mice with liver damage. Results: We found that sorafenib induced MAPK activation in HSCs, and promoted their myofibroblast differentiation. Combining sorafenib with a MEK inhibitor suppressed both paradoxical MAPK activation and HSC activation in vitro, and alleviated liver fibrosis in a CCl4-induced murine model of liver damage. Furthermore, treatment with sorafenib/MEK inhibitor-loaded CXCR4-targeted NPs significantly suppressed hepatic fibrosis progression and further prevented fibrosis-associated HCC development and liver metastasis. Conclusions: Our results show that combined delivery of sorafenib and a MEK inhibitor via CXCR4-targeted NPs can prevent activation of ERK in activated HSCs and has anti-fibrotic effects in the CCl4-induced murine model. Targeting HSCs represents a promising strategy to prevent the development and progression of fibrosis-associated HCC.

Docetaxel-carboxymethylcellulose nanoparticles ameliorate CCl4-induced hepatic fibrosis in mice.

Chronic liver diseases have recently garnered substantial attention as a leading cause of death around the world. During the progression of liver fibrosis/cirrhosis induced by chronic liver injury, hepatic stellate cells (HSCs) play key roles in the regulation of liver fibrogenesis and can even accelerate the progression of hepatocellular carcinoma (HCC). Thus, inhibition of HSC activation or suppression of inflammatory cytokine secretion by HSCs may be an efficient therapeutic strategy to ameliorate liver fibrosis/cirrhosis. In this study, we demonstrated that Cellax NPs (Carboxymethylcellulose - docetaxel-conjugated nanoparticles), which are nanoscale Pegylated carboxymethylcellulose - DTX conjugates, selectively target activated HSCs and abrogate their fibrogenic properties in vitro. Furthermore, Cellax NPs alleviated CCl4-induced hepatic fibrosis and suppressed HCC progression in a clinically relevant HCC model associated with underlying liver fibrosis in vivo. Taken together, Cellax NPs demonstrate great therapeutic promise as a treatment for liver fibrosis and cancer.