Bioinspired artificial exosomes based on lipid nanoparticles carrying let-7b-5p promote angiogenesis in vitro and in vivo.

MicroRNAs (miRNAs) regulate gene expression by post-transcriptional inhibition of target genes. Proangiogenic small extracellular vesicles (sEVs; popularly identified with the name "exosomes") with a composite cargo of miRNAs are secreted by cultured stem cells and present in human biological fluids. Lipid nanoparticles (LNPs) represent an advanced platform for clinically approved delivery of RNA therapeutics. In this study, we aimed to (1) identify the miRNAs responsible for sEV-induced angiogenesis; (2) develop the prototype of bioinspired "artificial exosomes" (AEs) combining LNPs with a proangiogenic miRNA, and (3) validate the angiogenic potential of the bioinspired AEs. We previously reported that human sEVs from bone marrow (BM)-CD34+ cells and pericardial fluid (PF) are proangiogenic. Here, we have shown that sEVs secreted from saphenous vein pericytes and BM mesenchymal stem cells also promote angiogenesis. Analysis of miRNA datasets available in-house or datamined from GEO identified the let-7 family as common miRNA signature of the proangiogenic sEVs. LNPs with either hsa-let-7b-5p or cyanine 5 (Cy5)-conjugated Caenorhabditis elegans miR-39 (Cy5-cel-miR-39; control miRNA) were prepared using microfluidic micromixing. let-7b-5p-AEs did not cause toxicity and transferred functionally active let-7b-5p to recipient endothelial cells (ECs). let-7b-AEs also improved EC survival under hypoxia and angiogenesis in vitro and in vivo. Bioinspired proangiogenic AEs could be further developed into innovative nanomedicine products targeting ischemic diseases.

Triggered-release polymeric conjugate micelles for on-demand intracellular drug delivery.

Nanoscale drug delivery platforms have been developed over the past four decades that have shown promising clinical results in several types of cancer and inflammatory disorders. These nanocarriers carrying therapeutic payloads are maximizing the therapeutic outcomes while minimizing adverse effects. Yet one of the major challenges facing drug developers is the dilemma of premature versus on-demand drug release, which influences the therapeutic regiment, efficacy and potential toxicity. Herein, we report on redox-sensitive polymer-drug conjugate micelles for on-demand intracellular delivery of a model active agent, curcumin. Biodegradable methoxy poly(ethylene glycol)-poly(lactic acid) copolymer (mPEG-PLA) was conjugated with curcumin via a disulfide bond or ester bond (control), respectively. The self-assembled redox-sensitive micelles exhibited a hydrodynamic size of 115.6 ± 5.9 (nm) with a zeta potential of -10.6 ± 0.7 (mV). The critical micelle concentration was determined at 6.7 ± 0.4 (µg mL(-1)). Under sink conditions with a mimicked redox environment (10 mM dithiothreitol), the extent of curcumin release at 48 h from disulfide bond-linked micelles was nearly three times higher compared to the control micelles. Such rapid release led to a lower half maximal inhibitory concentration (IC50) in HeLa cells at 18.5 ± 1.4 (µg mL(-1)), whereas the IC50 of control micelles was 41.0 ± 2.4 (µg mL(-1)). The cellular uptake study also revealed higher fluorescence intensity for redox-sensitive micelles. In conclusion, the redox-sensitive polymeric conjugate micelles could enhance curcumin delivery while avoiding premature release, and achieving on-demand release under the high glutathione concentration in the cell cytoplasm. This strategy opens new avenues for on-demand drug release of nanoscale intracellular delivery platforms that ultimately might be translated into pre-clinical and future clinical practice.

The immunostimulatory nature of mRNA lipid nanoparticles.

mRNA-Lipid nanoparticles (LNPs) are at the forefront of global medical research. With the development of mRNA-LNP vaccines to combat the COVID-19 pandemic, the clinical potential of this platform was unleashed. Upon administering 16 billion doses that protected billions of people, it became clear that a fraction of them witnessed mild and in some cases even severe adverse effects. Therefore, it is paramount to define the safety along with the therapeutic efficacy of the mRNA-LNP platform for the successful translation of new genetic medicines based on this technology. While mRNA was the effector molecule of this platform, the ionizable lipid component of the LNPs played an indispensable role in its success. However, both of these components possess the ability to induce undesired immunostimulation, which is an area that needs to be addressed systematically. The immune cell agitation caused by this platform is a two-edged sword as it may prove beneficial for vaccination but detrimental to other applications. Therefore, a key challenge in advancing the mRNA-LNP drug delivery platform from bench to bedside is understanding the immunostimulatory behavior of these components. Herein, we provide a detailed overview of the structural modifications and immunogenicity of synthetic mRNA. We discuss the effect of ionizable lipid structure on LNP functionality and offer a mechanistic overview of the ability of LNPs to elicit an immune response. Finally, we shed some light on the current status of this technology in clinical trials and discuss a few challenges to be addressed to advance the field.

Delivery of nucleic acid based genome editing platforms via lipid nanoparticles: Clinical applications.

CRISPR/Cas technology presents a promising approach for treating a wide range of diseases, including cancer and genetic disorders. Despite its potential, the translation of CRISPR/Cas into effective in-vivo gene therapy encounters challenges, primarily due to the need for safe and efficient delivery mechanisms. Lipid nanoparticles (LNPs), FDA-approved for RNA delivery, show potential for delivering also CRISPR/Cas, offering the capability to efficiently encapsulate large mRNA molecules with single guide RNAs. However, achieving precise targeting in-vivo remains a significant obstacle, necessitating further research into optimizing LNP formulations. Strategies to enhance specificity, such as modifying LNP structures and incorporating targeting ligands, are explored to improve organ and cell type targeting. Furthermore, the development of base and prime editing technology presents a potential breakthrough, offering precise modifications without generating double-strand breaks (DSBs). Prime editing, particularly when delivered via targeted LNPs, holds promise for treating diverse diseases safely and precisely. This review assesses both the progress made and the persistent challenges faced in using LNP-encapsulated CRISPR-based technologies for therapeutic purposes, with a particular focus on clinical translation.

Mechanisms and Barriers in Nanomedicine: Progress in the Field and Future Directions.

In recent years, steady progress has been made in synthesizing and characterizing engineered nanoparticles, resulting in several approved drugs and multiple promising candidates in clinical trials. Regulatory agencies such as the Food and Drug Administration and the European Medicines Agency released important guidance documents facilitating nanoparticle-based drug product development, particularly in the context of liposomes and lipid-based carriers. Even with the progress achieved, it is clear that many barriers must still be overcome to accelerate translation into the clinic. At the recent conference workshop "Mechanisms and Barriers in Nanomedicine" in May 2023 in Colorado, U.S.A., leading experts discussed the formulation, physiological, immunological, regulatory, clinical, and educational barriers. This position paper invites open, unrestricted, nonproprietary discussion among senior faculty, young investigators, and students to trigger ideas and concepts to move the field forward.

Lipid nanoparticles-loaded with toxin mRNA represents a new strategy for the treatment of solid tumors.

Background and rationale: Cancer therapy have evolved remarkably over the past decade, providing new strategies to inhibit cancer cell growth using immune modulation, with or without gene therapy. Specifically, suicide gene therapies and immunotoxins have been investigated for the treatment of tumors by direct cancer cell cytotoxicity. Recent advances in mRNA delivery also demonstrated the potential of mRNA-based vaccines and immune-modulators for cancer therapeutics by utilizing nanocarriers for mRNA delivery. Methods: We designed a bacterial toxin-encoding modified mRNA, delivered by lipid nanoparticles into a B16-melanoma mouse model. Results: We showed that local administration of LNPs entrapping a modified mRNA that encodes for a bacterial toxin, induced significant anti-tumor effects and improved overall survival of treated mice. Conclusions: We propose mmRNA-loaded LNPs as a new class of anti-tumoral, toxin-based therapy.

Transport by circulating myeloid cells drives liposomal accumulation in inflamed synovium.

The therapeutic potential of liposomes to deliver drugs into inflamed tissue is well documented. Liposomes are believed to largely transport drugs into inflamed joints by selective extravasation through endothelial gaps at the inflammatory sites, known as the enhanced permeation and retention effect. However, the potential of blood-circulating myeloid cells for the uptake and delivery of liposomes has been largely overlooked. Here we show that myeloid cells can transport liposomes to inflammatory sites in a collagen-induced arthritis model. It is shown that the selective depletion of the circulating myeloid cells reduces the accumulation of liposomes up to 50-60%, suggesting that myeloid-cell-mediated transport accounts for more than half of liposomal accumulation in inflamed regions. Although it is widely believed that PEGylation inhibits premature liposome clearance by the mononuclear phagocytic system, our data show that the long blood circulation times of PEGylated liposomes rather favours uptake by myeloid cells. This challenges the prevailing theory that synovial liposomal accumulation is primarily due to the enhanced permeation and retention effect and highlights the potential for other pathways of delivery in inflammatory diseases.

Principles for designing an optimal mRNA lipid nanoparticle vaccine.

mRNA Lipid nanoparticles (LNPs) have recently been propelled onto the center stage of therapeutic platforms due to the success of the SARS-CoV-2 mRNA LNP vaccines (mRNA-1273 and BNT162b2), with billions of mRNA vaccine doses already shipped worldwide. While mRNA vaccines seem like an overnight success to some, they are in fact a result of decades of scientific research. The advantage of mRNA-LNP vaccines lies in the modularity of the platform and the rapid manufacturing capabilities. However, there is a multitude of choices to be made when designing an optimal mRNA-LNP vaccine regarding efficacy, stability and toxicity. Herein, we provide a brief on what we consider to be the most important aspects to cover when designing mRNA-LNPs from what is currently known and how to optimize them. Lastly, we give our perspective on which of these aspects is most crucial and what we believe are the next steps required to advance the field.

Dual-Targeted Lipid Nanotherapeutic Boost for Chemo-Immunotherapy of Cancer.

Chemo-immunotherapy is a combination of "standard-of-care" chemotherapy with immunotherapy and it is considered the most advanced therapeutic modality for various types of cancers. However, many cancer patients still poorly respond to current regimen of chemo-immunotherapy and suggest nanotherapeutics as a boosting agent. Recently, heme oxygenase-1 (HO1) is shown to act as an immunotherapeutic molecule in tumor myeloid cells, in addition to general chemoresistance function in cancer cells suggesting that HO1-targeted therapeutics can become a novel, optimal strategy for boosting chemo-immunotherapy in the clinic. Currently the available HO1-inhibitors demonstrate serious adverse effects in clinical use. Herein, tumor myeloid cell- and cancer cell-dual targeted HO1-inhibiting lipid nanotherapeutic boost (T-iLNTB) is developed using RNAi-loaded lipid nanoparticles. T-iLNTB-mediated HO1-inhibition sensitizes cancer cells to "standard-of-care" chemotherapeutics by increasing immunogenic cell death, and directly reprograms tumor myeloid cells with distinguished phenotype. Furthermore, tumor myeloid cell reprogramming by T-iLNTB induces CD8+ cytotoxic T cell recruitment, which drives "Cold-to-Hot" transition and correlates with improved responsiveness to immune checkpoint inhibitor in combination therapy. Finally, ex vivo study proves that HO1-inhibition directly affects tumor macrophage differentiation. This study demonstrates the potential of T-iLNTB as a novel therapeutic modality for boosting chemo-immunotherapy.

A lipid nanoparticle platform for mRNA delivery through repurposing of cationic amphiphilic drugs.

Since the recent clinical approval of siRNA-based drugs and COVID-19 mRNA vaccines, the potential of RNA therapeutics for patient healthcare has become widely accepted. Lipid nanoparticles (LNPs) are currently the most advanced nanocarriers for RNA packaging and delivery. Nevertheless, the intracellular delivery efficiency of state-of-the-art LNPs remains relatively low and safety and immunogenicity concerns with synthetic lipid components persist, altogether rationalizing the exploration of alternative LNP compositions. In addition, there is an interest in exploiting LNP technology for simultaneous encapsulation of small molecule drugs and RNA in a single nanocarrier. Here, we describe how well-known tricyclic cationic amphiphilic drugs (CADs) can be repurposed as both structural and functional components of lipid-based NPs for mRNA formulation, further referred to as CADosomes. We demonstrate that selected CADs, such as tricyclic antidepressants and antihistamines, self-assemble with the widely-used helper lipid DOPE to form cationic lipid vesicles for subsequent mRNA complexation and delivery, without the need for prior lipophilic derivatization. Selected CADosomes enabled efficient mRNA delivery in various in vitro cell models, including easy-to-transfect cancer cells (e.g. human cervical carcinoma HeLa cell line) as well as hard-to-transfect primary cells (e.g. primary bovine corneal epithelial cells), outperforming commercially available cationic liposomes and state-of-the-art LNPs. In addition, using the antidepressant nortriptyline as a model compound, we show that CADs can maintain their pharmacological activity upon CADosome incorporation. Furthermore, in vivo proof-of-concept was obtained, demonstrating CADosome-mediated mRNA delivery in the corneal epithelial cells of rabbit eyes, which could pave the way for future applications in ophthalmology. Based on our results, the co-formulation of CADs, helper lipids and mRNA into lipid-based nanocarriers is proposed as a versatile and straightforward approach for the rational development of drug combination therapies.

RNAi-mediated CCR5 silencing by LFA-1-targeted nanoparticles prevents HIV infection in BLT mice.

RNA interference (RNAi)-mediated knockdown of gene expression offers a novel treatment strategy for human immunodeficiency virus (HIV) infection. However, the major hurdle for clinical use is a practical strategy for small interfering RNA (siRNA) delivery to the multiple immune cell types important in viral pathogenesis. We have developed a novel immunoliposome method targeting the lymphocyte function-associated antigen-1 (LFA-1) integrin expressed on all leukocytes and evaluated it for systemic delivery of siRNA in a humanized mouse model. We show that in vivo administration of the LFA-1 integrin-targeted and stabilized nanoparticles (LFA-1 I-tsNPs) results in selective uptake of siRNA by T cells and macrophages, the prime targets of HIV. Further, in vivo administration of anti-CCR5 siRNA/LFA-1 I-tsNPs resulted in leukocyte-specific gene silencing that was sustained for 10 days. Finally, humanized mice challenged with HIV after anti-CCR5 siRNA treatment showed enhanced resistance to infection as assessed by the reduction in plasma viral load and disease-associated CD4 T-cell loss. This study demonstrates the potential in vivo applicability of LFA-1-directed siRNA delivery as anti-HIV prophylaxis.

An ovarian spheroid based tumor model that represents vascularized tumors and enables the investigation of nanomedicine therapeutics.

The failure of cancer therapies in clinical settings is often attributed to the lack of a relevant tumor model and pathological heterogeneity across tumor types in the clinic. The objective of this study was to develop a robust in vivo tumor model that better represents clinical tumors for the evaluation of anti-cancer therapies. We successfully developed a simple mouse tumor model based on 3D cell culture by injecting a single spheroid and compared it to a tumor model routinely used by injecting cell suspension from 2D monolayer cell culture. We further characterized both tumors with cellular markers for the presence of myofibroblasts, pericytes, endothelial cells and extracellular matrix to understand the role of the tumor microenvironment. We further investigated the effect of chemotherapy (doxorubicin), nanomedicine (Doxil®), biological therapy (Avastin®) and their combination. Our results showed that the substantial blood vasculature in the 3D spheroid model enhances the delivery of Doxil® by 2.5-fold as compared to the 2D model. Taken together, our data suggest that the 3D tumors created by simple subcutaneous spheroid injection represents a robust and more vascular murine tumor model which is a clinically relevant platform to test anti-cancer therapy in solid tumors.

CRISPR-Cas9 genome editing using targeted lipid nanoparticles for cancer therapy.

Harnessing CRISPR-Cas9 technology for cancer therapeutics has been hampered by low editing efficiency in tumors and potential toxicity of existing delivery systems. Here, we describe a safe and efficient lipid nanoparticle (LNP) for the delivery of Cas9 mRNA and sgRNAs that use a novel amino-ionizable lipid. A single intracerebral injection of CRISPR-LNPs against PLK1 (sgPLK1-cLNPs) into aggressive orthotopic glioblastoma enabled up to ~70% gene editing in vivo, which caused tumor cell apoptosis, inhibited tumor growth by 50%, and improved survival by 30%. To reach disseminated tumors, cLNPs were also engineered for antibody-targeted delivery. Intraperitoneal injections of EGFR-targeted sgPLK1-cLNPs caused their selective uptake into disseminated ovarian tumors, enabled up to ~80% gene editing in vivo, inhibited tumor growth, and increased survival by 80%. The ability to disrupt gene expression in vivo in tumors opens new avenues for cancer treatment and research and potential applications for targeted gene editing of noncancerous tissues.

Leukocyte-specific siRNA delivery revealing IRF8 as a potential anti-inflammatory target.

Interferon regulatory factor 8 (IRF8) protein plays a critical role in the differentiation, polarization, and activation of mononuclear phagocytic cells. In light of previous studies, we explored the therapeutic potential of IRF8 inhibition as immunomodulatory therapy for inflammatory bowel disease (IBD). To this end, we utilized siRNA-loaded lipid-based nanoparticles (siLNPs) and demonstrated a ∼90% reduction of IRF8 mRNA levels in vitro (PV < 0.0001), alongside a notable reduction in IRF8 protein. Moreover, silencing IRF8 ex vivo in splenocytes lead to a profound downregulation of IRF8 protein, followed by an immunomodulatory effect, as represented by a decrease in the secretion of TNFα, IL6 and IL12/IL23 (IL12p40) proinflammatory cytokines (PV = 0.0045, 0.0330, <0.0001, respectively). In order to silence IRF8 in vivo, selectively in inflammatory leukocytes, we used siLNPs that were coated with anti-Ly6C antibodies via our recently published ASSET targeting approach. Through this strategy, we have demonstrated a selective binding of the targeted-LNPs (T-LNPs) to Ly6C + inflammatory leukocytes. Finally, an immunomodulatory effect was demonstrated in vivo in an IBD mouse model with a profound decrease of TNFα, IL6, IL12/IL23, and IL1ß pro-inflammatory cytokines (n = 5, PV < 0.0001, <0.0001, <0.0001, 0.02, respectively) and an improvement of colon-morphology as assessed by colon-length measurements and colonoscopy (PV < 0.0001). Overall, using antibody-targeted siLNPs, we showed a notable reduction of IRF8 mRNA and protein and demonstrated a targeted immunomodulation therapeutic effect ex vivo and in vivo, in the DSS colitis model. We claim that a selective silencing of IRF8 in inflammatory leukocytes (such as Ly6C+) may serve as a therapeutic approach for treating inflammatory disorders.

Triggered ferroptotic polymer micelles for reversing multidrug resistance to chemotherapy.

Drug-tolerant persister cancer cells (PCCs) play an important role in the development of multidrug resistance (MDR) to anti-cancer drugs. This is due to the strong link between PCCs formation and epithelial-mesenchymal transition (EMT), as well as the low numbers of PCCs. In addition, PCC removal by traditional cytotoxic agents is poor due to the intrinsic high MDR activity in these cells. As a novel programmed cell death pathway, ferroptosis shows high potency to eliminate cells at the EMT state via manipulating intracellular redox homeostasis. The aim of this work was to utilize triggered ferroptotic polymer micelles for PCCs removal and MDR reversal both in vitro and in vivo. The micelles were made of arachidonic acid-conjugated amphiphilic copolymer that can enable rapid cargo release upon free radical-triggering in the tumor microenvironment. A potent ferroptotic inducer, RSL3 was encapsulated in the micelles to target the glutathione peroxidase 4 (GPX4). In the model resistant human ovarian adenocarcinoma cells, the RSL3 micelles were 30-fold more toxic than activatable control micelles due to the ferroptotic machinery. The lipid peroxidation-induced intracellular glutathione level reduction also made a contribution, which enhanced the potency of RSL3 for ferroptosis induction and enabled the drug-loaded micelles all-active. As an index of PCCs population, the level of CD133+ and aldehyde dehydrogenase (ALDH+) biomarker was significantly lower for the ferroptotic micelles in contrast to the control. The potency of ferroptotic micelles regarding PCCs reduction was proved by the in vitro soft agar colony forming assay. The in vivo anti-tumor efficacy of triggered micelles was further demonstrated in tumor-bearing nude mice in terms of PCCs biomarkers, tumor growth inhibition, mice survival, and GPX4 inhibition. This work demonstrates a novel strategy to overcome cancer MDR via the tailored ferroptotic micelles, which opens new avenues for managing resistant tumors.

A modular platform for targeted RNAi therapeutics.

Previous studies have identified relevant genes and signalling pathways that are hampered in human disorders as potential candidates for therapeutics. Developing nucleic acid-based tools to manipulate gene expression, such as short interfering RNAs1-3 (siRNAs), opens up opportunities for personalized medicine. Yet, although major progress has been made in developing siRNA targeted delivery carriers, mainly by utilizing monoclonal antibodies (mAbs) for targeting4-8, their clinical translation has not occurred. This is in part because of the massive development and production requirements and the high batch-to-batch variability of current technologies, which rely on chemical conjugation. Here we present a self-assembled modular platform that enables the construction of a theoretically unlimited repertoire of siRNA targeted carriers. The self-assembly of the platform is based on a membrane-anchored lipoprotein that is incorporated into siRNA-loaded lipid nanoparticles that interact with the antibody crystallizable fragment (Fc) domain. We show that a simple switch of eight different mAbs redirects the specific uptake of siRNAs by diverse leukocyte subsets in vivo. The therapeutic potential of the platform is demonstrated in an inflammatory bowel disease model by targeting colon macrophages to reduce inflammatory symptoms, and in a Mantle Cell Lymphoma xenograft model by targeting cancer cells to induce cell death and improve survival. This modular delivery platform represents a milestone in the development of precision medicine.

Hyaluronan is a key component in cryoprotection and formulation of targeted unilamellar liposomes.

Lyophilized unilamellar liposomes (ULV), the dosage form of choice for shelf-life, revert upon reconstitution to the larger multilamellar liposomes (MLV), which is detrimental to the many carrier-mediated therapies that require small particles. High doses of sugars such as trehalose, sucrose and others, included in the original formulations for cryoprotection, were shown to prevent the conversion to MLV. In this study we set out to test whether hyaluronan (HA), the surface-bound ligand in our previously developed targeted bioadhesive liposomes (BAL), can also act as a cryoprotectant. The studies included structural and physicochemical characterization of original and reconstituted hyaluronan-ULV (HA-ULV). For each HA-ULV, similar regular ULV (RL-ULV) served as controls. Four properties were tested: particle size, zeta potential, encapsulation efficiency and half-life of drug release (tau(1/2)), for three drugs-chloramphenicol (CAM), vinblastine (VIN) and mitomycin C (MMC). Encapsulation efficiencies of the original systems were quite alike for similar RL-ULV and HA-ULV ranging from 25% to 70%. All systems acted as sustained-release drug depots, tau(1/2) ranging from 1.3 to 5.3 days. Drug species and lipid composition were the major determinants of encapsulation and release magnitudes. By all tests, as anticipated, lyophilization generated significant changes in the reconstituted RL-ULV: 17-fold increase in diameter; tripling of zeta potential; 25-60% drop in encapsulation efficiencies; 25-30% decrease in tau(1/2). In contrast, the reconstituted HA-ULV retained the same dimensions, zeta potentials, encapsulation efficiencies and tau(1/2) of the original systems. These data clearly show HA to be a cryoprotectant, adding another clinically relevant advantage to HA-BAL. We propose that, like the sugars, HA cryoprotects by providing substitute structure-stabilizing H-bonds.

Tumor-targeted hyaluronan nanoliposomes increase the antitumor activity of liposomal Doxorubicin in syngeneic and human xenograft mouse tumor models.

Naturally occurring high-Mr hyaluronan, bound to the surface of nanoliposomes (denoted targeted hyaluronan liposomes, or tHA-LIP), is a candidate for active targeting to tumors, many of which overexpress the hyaluronan receptors CD44 and RHAMM. The surface-bound hyaluronan also provides a hydrophilic coat that, similar to polyethylene glycol, may promote long-term circulation. We recently reported the successful targeting of mitomycin C, mediated by tHA-LIP, in tumor-bearing syngeneic mice. Hypothesizing that this targeting is carrier-specific, rather than drug-specific, we report here studies with doxorubicin (DXR)-loaded tHA-LIP, in syngeneic and human xenograft models. Saline, free DXR, DXR-loaded nontargeted liposomes (nt-LIP), and Doxil served as controls. The tHA-LIP were long-circulating, more than all controls, in healthy and tumor-bearing (C57BL/6/B16F10.9; BALB/c/C-26) mice. Mediated by tHA-LIP, DXR accumulation in tumor-bearing lungs was 30-, 6.7-, and 3.5-fold higher than free DXR, nt-LIP, and Doxil, respectively. Key indicators of therapeutic responses--tumor progression, metastatic burden, and survival--were superior (P < .001) in animals receiving DXR-loaded tHA-LIP compared with controls, in tumor-bearing syngeneic mice (BDF1/P388/ADR ascites, C57BL/6/B16F10.9 lung metastasis, and BALB/c/C-26 solid tumors), and in nude mice bearing PANC-1 solid tumors. In conclusion, tHA-LIP, performing as tumor-targeted carriers, have the potential to join the arsenal of carrier-formulated anticancer drugs.

Modulating cancer multidrug resistance by sertraline in combination with a nanomedicine.

Inherent and acquired multiple drug resistance (MDR) to chemotherapeutic drugs is a major obstacle in cancer treatment. The ATP Binding Cassettes (ABC) transporter super family that act as extrusion pumps such as P-glycoprotein and multidrug-resistance-associated-proteins have prominent roles in cancer MDR. One of the most efficient strategies to modulate this active drug efflux from the cells is to physically block the pump proteins and thus change the balance between drug influx and efflux toward an accumulation of drug inside the cell, which eventually cumulates into cell death. MDR modulators (also known as chemosensitizers) were found among drugs approved for non-cancer indications. Yet, toxicity, adverse effects, and poor solubility at doses required for MDR reversal prevent their clinical application. Previous reports have shown that drugs belonging to the selective serotonin reuptake inhibitors (SSRI) family, which are clinically used as antidepressants, can act as effective chemosensitizers both in vitro and in vivo in tumor bearing mouse models. Here, we set out to explore whether sertraline (Zoloft®), a molecule belonging to the SSRI family, can be used as an MDR modulator. Combining sertraline with another FDA approved drug, Doxil® (pegylated liposomal doxorubicin), is expected to enhance the effect of chemotherapy while potentially reducing adverse effects. Our findings reveal that sertraline acts as a pump modulator in cellular models of MDR. In addition, in an aggressive and highly resistant human ovarian xenograft mouse model the use of sertraline in combination with Doxil® generated substantial reduction in tumor progression, with extension of the median survival of tumor-bearing mice. Taken together, our results show that sertraline could act as a clinically relevant cancer MDR inhibitor. Moreover, combining two FDA approved drugs, DOXIL®, which favor the influx of chemotherapy inside the malignant cell with sertraline, which blocks the extrusion pumps, could readily be available for clinical translation in the battle against resistant tumors.

Optimizing the biofabrication process of omentum-based scaffolds for engineering autologous tissues.

Omentum-based matrices fabricated by decellularization have the potential to serve as autologous scaffolds for tissue engineering. Transplantation of such scaffolds prepared from the patient's own biomaterial may reduce the immunogenic response after transplantation. Recently we reported on the potential of the decellularized omentum to support the assembly of functional vascularized cardiac patches. Here we compared five distinct protocols for omentum decellularization, utilizing chemical, physical and biological processes. We analyzed the efficiency of cell removal, scaffold macro and micro structure, biochemical composition and the ability of seeded cells to attach and proliferate in the matrix. Moreover, we assessed the ability of the distinct scaffolds to promote the organization of cardiac tissue.