Nanoliposome-mediated targeting of antibodies to tumors: IVIG antibodies as a model

A landscape of recent advances in lipid nanoparticles and their translational potential for the treatment of solid tumors

Lipid nanoparticles (LNPs) are biocompatible drug delivery systems that have found numerous applications in medicine. Their versatile nature enables the encapsulation and targeting of various types of medically relevant molecular cargo, including oligonucleotides, proteins, and small molecules for the treatment of diseases, such as cancer. Cancers that form solid tumors are particularly relevant for LNP-based therapeutics due to the enhanced permeation and retention effect that allows nanoparticles to accumulate within the tumor tissue. Additionally, LNPs can be formulated for both locoregional and systemic delivery depending on the tumor type and stage. To date, LNPs have been used extensively in the clinic to reduce systemic toxicity and improve outcomes in cancer patients by encapsulating chemotherapeutic drugs. Next-generation lipid nanoparticles are currently being developed to expand their use in gene therapy and immunotherapy, as well as to enable the co-encapsulation of multiple drugs in a single system. Other developments include the design of targeted LNPs to specific cells and tissues, and triggerable release systems to control cargo delivery at the tumor site. This review paper highlights recent developments in LNP drug delivery formulations and focuses on the treatment of solid tumors, while also discussing some of their current translational limitations and potential opportunities in the field.

A comprehensive review on transethosomes as a novel vesicular approach for drug delivery through transdermal route

Drug delivery through transdermal route is one of the effective methods for the application of drugs. It overcomes many drawbacks which are encountered with the oral route. Moreover, many drugs are not able to pass through the stratum corneum, which is the main barrier for the transdermal drug delivery. Formation of ultra-deformable vesicles (UDVs) is a novel technique for the transdermal applications of the drugs. Transethosomes (TEs), ethosomes, and transferosomes are all part of the UDV. Because of the presence of increased concentrations of ethanol, phospholipids, and edge activators, TEs provide improved drug permeation through the stratum corneum. Because of the elasticity of TEs, drug penetration into the deeper layer of skin also increases. TEs can be prepared using a variety of techniques, including the cold method, hot method, thin film hydration method, and the ethanol injection method. It increases patient adherence and compliance because it is a non-invasive procedure of administering drugs. Characterization of the TEs includes pH determination, size and shape, zeta potential, particle size determination, transition temperature, drug content, vesicle stability, and skin permeation studies. These vesicular systems can be utilized to deliver a variety of medications transdermally, including analgesics, antibiotics, antivirals, and anticancer and arthritis medications. This review aims to describe vesicular approaches that had been used to overcome the barrier for the transdermal delivery of drug and also describes brief composition, method of preparation, characterization tests, mechanism of penetration of TEs, as well as highlighted various applications of TEs in medicine.

Optimizing nanoliposomal formulations: Assessing factors affecting entrapment efficiency of curcumin-loaded liposomes using machine learning

BACKGROUND

Curcumin faces challenges in clinical applications due to its low bioavailability and poor water solubility. Liposomes have emerged as a promising delivery system for curcumin. This study aims to apply ensemble learning, a machine learning technique, to determine the most effective experimental conditions for formulating stable curcumin-loaded liposomes with a high entrapment efficiency (EE).

METHODS

Two liposomal formulations composed of HSPC:DPPG:Chol:DSPE-mPEG2000 and HSPC:Chol:DSPE-mPEG2000 at 55:5:35:5 and 55:40:5 M ratios, respectively, were prepared using the remote loading method, and their particle size and polydispersity index (PDI) were determined using Dynamic Light Scattering. To model the impact of five factors (molar ratios, particle size, sonication time, pH, and PDI) on EE%, the Least-squares boosting (LSBoost) ensemble learning algorithm was employed due to its capability to effectively handle nonlinear and non-stationary problems. The implementation and optimization of LSBoost were performed using MATLAB R2020a. The dataset was randomly split into training and testing sets, with 70% allocated for training. The mean absolute error (MAE) was used as the cost function to evaluate model performance. Additionally, a novel approach was employed to visualize the results using 3D plots, facilitating practical interpretation.

RESULTS

The optimal model exhibited an MAE of 3.61, indicating its robust predictive capability. The study identified several optimal conditions for achieving the highest EE value of 100%. However, to ensure both the highest EE value and a suitable particle size, it is recommended to set the following conditions: a molar ratio of 55:5:35:5, a PDI within the range of 0.09-0.13, a particle size of approximately 130 nm, a sonication time of 30 min, and a pH within the range of 7.2-8. It is worth mentioning that adjusting the molar ratio to 55:40:5 resulted in a maximum EE of 88.38%.

CONCLUSION

These findings underscore the high performance of ensemble learning in accurately predicting and optimizing the EE of the curcumin-loaded liposomes. The application of this technique provides valuable insights and holds promise for the development of efficient drug delivery systems.

Application of ensemble machine learning approach to assess the factors affecting size and polydispersity index of liposomal nanoparticles

Liposome nanoparticles have emerged as promising drug delivery systems due to their unique properties. Assessing particle size and polydispersity index (PDI) is critical for evaluating the quality of these liposomal nanoparticles. However, optimizing these parameters in a laboratory setting is both costly and time-consuming. This study aimed to apply a machine learning technique to assess the impact of specific factors, including sonication time, extrusion temperature, and compositions, on the size and PDI of liposomal nanoparticles. Liposomal solutions were prepared and subjected to sonication with varying values for these parameters. Two compositions: (A) HSPC:DPPG:Chol:DSPE-mPEG2000 at 55:5:35:5 molar ratio and (B) HSPC:Chol:DSPE-mPEG2000 at 55:40:5 molar ratio, were made using remote loading method. Ensemble learning (EL), a machine learning technique, was employed using the Least-squares boosting (LSBoost) algorithm to accurately model the data. The dataset was randomly split into training and testing sets, with 70% allocated for training. The LSBoost algorithm achieved mean absolute errors of 1.652 and 0.0105 for modeling the size and PDI, respectively. Under conditions where the temperature was set at approximately 60 °C, our EL model predicted a minimum particle size of 116.53 nm for composition (A) with a sonication time of approximately 30 min. Similarly, for composition (B), the model predicted a minimum particle size of 129.97 nm with sonication times of approximately 30 or 55 min. In most instances, a PDI of less than 0.2 was achieved. These results highlight the significant impact of optimizing independent factors on the characteristics of liposomal nanoparticles and demonstrate the potential of EL as a decision support system for identifying the best liposomal formulation. We recommend further studies to explore the effects of other independent factors, such as lipid composition and surfactants, on liposomal nanoparticle characteristics.

Nanoliposomal VEGF-R2 peptide vaccine acts as an effective therapeutic vaccine in a murine B16F10 model of melanoma

Background

The vascular endothelial growth factor receptor-2 (VEGFR-2) plays an important role in melanoma development and progression. Peptide vaccines have shown great potential in cancer immunotherapy by targeting VEGFR-2 as a tumor-associated antigen and boosting the immune response against both tumor cells and tumor endothelial cells. Despite this, the low efficiency of peptide vaccines has resulted in moderate therapeutic results in the majority of studies. Enhancing the delivery of peptide vaccines using nanoliposomes is an important strategy for improving the efficacy of peptide vaccines. In this regard, we designed VEGFR-2-derived peptides restricted to both mouse MHC I and human HLA-A*02:01 using immunoinformatic tools and selected three peptides representing the highest binding affinities. The peptides were encapsulated in nanoliposomal formulations using the film method plus bath sonication and characterized for their colloidal properties.

Results

The mean diameter of peptide-encapsulated liposomes was around 135 nm, zeta potential of - 17 mV, and encapsulation efficiency of approximately 70%. Then, vaccine formulations were injected subcutaneously in mice bearing B16F10-established melanoma tumors and their efficiency in triggering immunological, and anti-tumor responses was evaluated. Our results represented that one of our designed VEGFR-2 peptide nanoliposomal formulations (Lip-V1) substantially activated CD4+ (p < 0.0001) and CD8+ (P < 0.001) T cell responses and significantly boosted the production of IFN-γ (P < 0.0001) and IL-4 (P < 0.0001). Furthermore, this formulation led to a significant decrease in tumor volume (P < 0.0001) and enhanced survival (P < 0.05) in mice.

Conclusion

Our findings suggest that the nanoliposomal formulation containing VEGFR-2 peptides could be a promising therapeutic vaccination approach capable of eliciting strong antigen-specific immunologic and anti-tumor responses.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12645-023-00213-7.

Engineered nanomedicines for augmenting the efficacy of colorectal cancer immunotherapy

Colorectal cancer (CRC) is one of the most devastating diseases worldwide. Immunotherapeutic agents for CRC treatment have shown limited efficacy due to the immunosuppressive tumor microenvironment (TME). In this context, various types of nanoparticles (NPs) have been used to reverse the immunosuppressive TME, potentiate the effect of immunotherapeutic agents and reduce their systemic side effects. Many advantages could be offered by NPs, related to drug-loading efficiency, particle size and others that can potentially aid the delivery of immunotherapeutic agents. The recent research on how nano-based immunotherapy can remodel the immunosuppressive TME of CRC and hence boost the antitumor immune response, as well as the challenges that face clinical translation of NPs and future perspectives, are summarized in this review article.

The modern pharmacological approach to diabetes: innovative methods of monitoring and insulin treatment

INTRODUCTION

Diabetes mellitus, commonly known as just diabetes, is a group of metabolic disorders characterised by a high blood sugar level over a prolonged period of time. In order to maintain this blood glucose value in normal parameters, a careful monitoring of it and insulin administration are necessary.

AREAS COVERED

Thus, to facilitate this procedure, new blood glucose monitoring systems have been studied. The smart lens, the nano tattoo, non-invasive sensors based on reverse ionthophoresis and glucose oxidase - based continuous blood glucose monitoring systems, are the methods described in this study. Of course, not only is blood glucose monitoring important, but also the lifestyle of a drug or the way a drug is administered, especially in the cae of insulin. How insulin is administered is also a topic that we address in this article. In an attempt to promote compliance with the administration, we have discussed about new forms of administering insulin such as: oral, intranasal, administration on the oral mucosa and last but not least, transdermal administration.

EXPERT OPINION

Further, the attention of specialists should be directed to devices based on sensors, with a role in the interruption of insulin administration, in case of detection of hypoglycemia or the additional dose of insulin, if hyperglycemia is detected.

Docetaxel in combination with metformin enhances antitumour efficacy in metastatic breast carcinoma models: a promising cancer targeting based on PEGylated liposomes

OBJECTIVES

Metformin has been shown to kill cancer stem-like cells in genetically various types of breast carcinoma. With the aim to simultaneously eradicate the bulk population of tumour cells and the rare population of cancer stem-like cells in breast cancer tissues, we used the combination chemotherapy of docetaxel (DTX) with metformin (MET). Furthermore, we introduce an active loading method based on ammonium sulphate 250 mM (SA) for encapsulating docetaxel into liposomes.

METHODS

Docetaxel and metformin encapsulated into PEGylated liposomes with two different methods based on remote or passive loading methods, respectively. The size and surface charge of the liposomes were characterized. DTX content in the nanoliposomes was measured by the high-performance liquid chromatography method. The drug release profiles were evaluated in phosphate-buffered dextrose 5% with the pH of 6.5 and 7.4. We examined the antitumour activity of Taxotere (TAX), and liposomal formulation of DTX and MET as a monotherapy or combination therapy. The biodistribution of liposomes was also investigated using 99mTc hexamethyl propylene amine oxime method in BALB/c mice bearing 4T1 breast carcinoma tumours.

KEY FINDINGS

The final formulations were prepared according to the best physicochemical characteristics which were HSPC/mPEG2000-DSPE/Chol (DTX liposomes) and HSPC/DPPG/mPEG2000-DSPE/Chol (MET liposomes), at molar ratios of 85/5/10 and (55/5/5/35), respectively. In vivo experiments showed that when free or liposomal metformin used in combination with liposomal docetaxel, they prolonged median survival time (MST) from 31 in the control group to 46 days, which demonstrates their promising effects on the survival of the 4T1 breast carcinoma mice models. Moreover, combination therapies could significantly increase life span in comparison with phosphate-buffered saline (PBS) and Taxotere groups at the same dose. Furthermore, in the combination therapy study, treatment with DTX liposomes prepared by ammonium sulphate 250 mM buffer alone resulted in similar therapeutic efficacy to combination therapy. The biodistribution study exhibited significant accumulation of DTX liposomes in the tumours due to the Enhanced Permeability and Retention effect.

CONCLUSIONS

This study also showed that metformin-based combinatorial chemotherapies have superior efficacy versus their corresponding monotherapy counterparts at same doses. The findings confirm that liposomes based on ammonium sulphate 250 mM could be as a promising formulation for efficient DTX delivering and cancer targeting and therefore merit further investigations.

A Novel Multiepitope Vaccine Against Bladder Cancer Based on CTL and HTL Epitopes for Induction of Strong Immune Using Immunoinformatics Approaches

Bladder cancer is well-known cancer in two forms of muscle-invasive and non-muscle-invasive bladder cancer which is responsible for annual deaths worldwide. Common therapies methods are somewhat successful; however, these methods have the limitations such as the side effects of chemotherapy which necessitate the requirement for new preventive methods against bladder cancer. Hence, we explain a novel designed multi-epitope vaccine against bladder cancer using the immunoinformatics tool. Three well-known BLCAP, PRAM, and BAGE4 antigens were evaluated due to most repetitive CTL and HTL epitopes binding. IFNγ and IL10 inducer potential of selected epitopes were investigated, as well as liner and conformational B-cell epitopes. Human beta-defensin 3 and PADRE sequence were added to construct as adjuvants, along with EAAAK, AAY, and GGGS linkers to fuse CTL and HTL epitopes. Results showed this construct encodes a soluble, non-toxic, and non-allergic protein with 70 kDa molecular weight. Modeled 3D structure of vaccine was docked whit Toll-Like Receptors (TLR) of 7/8. Docking, molecular dynamics simulation and MMBPSA analysis confirmed stability of vaccine-TLR complexes. The immunogenicity showed this construct could elicit humoral and cellular immune responses. In silico and immunoinformatics evaluations suggest that this construct is a recombinant candidate vaccine against bladder cancer.

Development of a novel formulation method to prepare liposomal Epacadostat

BACKGROUND

One of the important metabolic pathways in cancer progression is tryptophan catabolism by the indoleamin-2,3-dioxygenase (IDO) enzyme, which suppresses the immune system and induces tolerance. Inhibition of IDO1 is an important therapeutic goal for immunotherapy in many cancers such as metastatic melanoma. Epacadostat (EPA) is a very strong inhibitor of IDO1, and its clinical studies are being performed in a higher clinical phase than other inhibitors. In this study, we have developed a new liposomal EPA formulation to reduce the dose, side effects, and treatment costs.

METHODS

Liposomes containing EPA were formulated using a novel remote loading method. Their morphology, particle size, surface charge, total phospholipid content, and drug loading were evaluated. Validation method studies to assay of EPA were carried out according to ICHQ2B guidelines. For in-vivo study, B16F10 melanoma bearing C57BL/6 mice were treated with the free or liposomal forms of EPA, and then monitored for tumor size and survival rate.

RESULTS

A validated method for EPA determination in liposomal form using UV-visible spectrophotometry was developed which was a precise, accurate and robust method. The particle size, zeta potential, and encapsulation efficacy of liposomes was 128.1 ± 1.1 nm, -16.5 ± 1 mV, and 64.9 ± 3.5, respectively. The half maximal inhibitory concentration (IC50) of liposomal EPA was 64 ng/ml that was lower than free EPA (128 ng/ml). In-vivo results also showed that tumor growth was slower in mice receiving liposomal EPA than in the group receiving free EPA.

CONCLUSION

A new method was developed to load EPA into liposomes. Moreover, the use of the nanoliposomal EPA showed more efficacy than EPA in inhibiting the tumor growth in melanoma model. Therefore, it might be used in further clinical studies as a good candidate for immunotherapy alone or in combination with other treatments.

Tumor-Targeting Liposomes with Transient Holes Allowing Intact Rituximab Internally

In this study, the strategy of transient generation of holes in the liposome surface has been shown to enable safe encapsulation of a high-molecular weight antibody (rituximab, M_w ∼140 kDa) within liposomes. These transient holes generated using our magnetoporation method allowed rituximab to safely enter the liposomes, and then the holes were plugged using hyaluronic acid grafted with 3-diethylaminopropylamine (DEAP). In the tumor microenvironment, the resulting liposomal rituximab was destabilized because of the ionization of the DEAP moiety at the acidic pH 6.5, resulting in extensive release of rituximab. Consequently, the rituximab released from the liposomes accumulated at high levels in tumors and bound to the CD20 receptors overexpressed on Burkitt lymphoma Ramos cells. This event led to significant enhancement in tumor cell ablation through rituximab-mediated complement-dependent cytotoxicity and Bcl-2 signaling inhibition-induced cell apoptosis.

Preparation of liposomes containing IFN-gamma and their potentials in cancer immunotherapy: In vitro and in vivo studies in a colon cancer mouse model

The purpose of this study was to prepare non-PEGylated (HSPC/DSPG/Chol, LIPF1) and PEGylated (HSPC/DSPG/Chol/mPEG2000-DSPE, LIPF2) liposomal formulations containing Interferon-gamma (IFN-γ) and evaluation their effects on macrophages and their antitumor properties. The results showed that the size of liposomal formulations LIP-F1 and LIP-F2 was 120 and 135 nm, respectively. The encapsulation efficiencies of LIP-F1 and LIP-F2 were 52.79% and 49.2%, respectively. Nitric Oxide Synthase (INOS) and arginase assays showed an increase in nitric oxide (NO) level and a reduction in arginase level after the treatment of M2 phenotype macrophage cell line with IFN-γ liposomes. The biodistribution study illustrated the amplitude of iodinated-IFN-γ liposomal formulations in the tumor site, the circulation time and tumor accumulation of LIP-F2 was significantly more than LIPF1. As a result, PEGylated liposomes containing IFN-γ induced significant antitumor responses due to the increased delivery of the cargo to the immune cells and induction of antitumor immune responses.

Encapsulated Checkpoint Blocker Before Chemotherapy: The Optimal Sequence of Anti-CTLA-4 and Doxil Combination Therapy

INTRODUCTION

Today, a new paradigm has emerged for cancer treatment introducing combination therapies. Doxil, a liposomal doxorubicin serving as a chemotherapeutic agent, is an effective immunogenic killer of cancer cells. Anti-CTLA-4 has been approved for the treatment of some cancers, including melanoma, but side effects have limited its therapeutic potential.

METHODS

In this study, two approaches were utilized to increase treatment efficiency and decrease the side effects of anti-CTLA-4, combining it with chemotherapy and encapsulation in a PEGylated liposome. A different sequence of anti-CTLA-4 and Doxil was assessed in combination therapy using non-liposomal and liposomal anti-CTLA-4.

RESULTS

Our results showed that liposomal anti-CTLA-4 reduced the size of established tumors and increased survival in comparison with non-liposomal anti-CTLA-4 in a well-established B16 mouse melanoma model. In combination therapy with Doxil, only the administration of anti-CTLA-4 before Doxil showed synergism in both non-liposomal and liposomal form and increased the CD8+/regulatory T cell ratio.

DISCUSSION

In summary, our results demonstrate the potential of utilizing a nanocarrier system for the delivery of checkpoint blockers, such as anti-CTLA-4 which further showed potential in a combination therapy, especially when administered before chemotherapy.

Meta-Analysis of Nanoparticle Delivery to Tumors Using a Physiologically Based Pharmacokinetic Modeling and Simulation Approach

Numerous studies have engineered nanoparticles with different physicochemical properties to enhance the delivery efficiency to solid tumors, yet the mean and median delivery efficiencies are only 1.48% and 0.70% of the injected dose (%ID), respectively, according to a study using a nonphysiologically based modeling approach based on published data from 2005 to 2015. In this study, we used physiologically based pharmacokinetic (PBPK) models to analyze 376 data sets covering a wide range of nanomedicines published from 2005 to 2018 and found mean and median delivery efficiencies at the last sampling time point of 2.23% and 0.76%ID, respectively. Also, the mean and median delivery efficiencies were 2.24% and 0.76%ID at 24 h and were decreased to 1.23% and 0.35%ID at 168 h, respectively, after intravenous administration. While these delivery efficiencies appear to be higher than previous findings, they are still quite low and represent a critical barrier in the clinical translation of nanomedicines. We explored the potential causes of this poor delivery efficiency using the more mechanistic PBPK perspective applied to a subset of gold nanoparticles and found that low delivery efficiency was associated with low distribution and permeability coefficients at the tumor site (P < 0.01). We also demonstrate how PBPK modeling and simulation can be used as an effective tool to investigate tumor delivery efficiency of nanomedicines.

Immunoenhancement of Recombinant Neisseria meningitides PorB Protein on Porcine Circovirus Type 2 and Mycoplasma hyopneumoniae Genetically Engineered Vaccines

BACKGROUND

Porcine circovirus and Mycoplasma hyopneumoniae can cause respiratory diseases in pigs, which cause serious economic loss in the worldwide pig industry. Currently, these infections are mainly prevented and controlled by vaccination. The new vaccines on the market are mainly composed of subunits and inactivated vaccines but usually have lower antigenicity than traditional live vaccines. Thus, there is an increasing need to develop new adjuvants that can cause rapid and long-lasting immunity to enhance the antigenic efficacy for vaccines. Studies have shown that meningococcal porin PorB can act as a ligand to combine with Toll-like receptors to activate the production of immunological projections and act as a vaccine immunological adjuvant.

OBJECTIVE

In this article, we expressed and purified the recombinant PorB protein and verified its immunogenicity against porcine circovirus type 2 and Mycoplasma hyopneumoniae genetically engineered vaccine.

METHODS

In this article, we used prokaryotic expression to express and purify recombinant PorB protein, four different concentrations of PorB protein, Freund's adjuvant with two genetically engineered vaccines were combined with subcutaneous immunization of mice.

RESULTS

Our study shows that the appropriate dose of the recombinant protein PorB can enhance the levels of humoral and cellular responses induced by two genetically engineered vaccines in a short period of time in mice. The PorB adjuvant group may cause statistically higher antibody titers for both genetically engineered vaccines compared to Freund's commercial adjuvant (P<0.001).

CONCLUSION

The recombinant protein PorB may be a good candidate adjuvant for improving the protective effect of vaccines against porcine circovirus type 2 and Mycoplasma hyopneumoniae, and the protein can be used for future practical applications.

Preparation, in vitro and in vivo evaluation of PLGA/Chitosan based nano-complex as a novel insulin delivery formulation

The smart self-regulated drug delivery systems for insulin administration are desirable to achieve glycemic control, and decrease the long-term micro- and macro vascular complications. In this study, we developed an injectable nano-complex formulation for closed-loop insulin delivery after subcutaneous administration and release of insulin in response to increased blood glucose levels. The nano-complex was prepared by mixing oppositely charged chitosan and PLGA nanoparticles. PLGA nanoparticles were prepared using double-emulsion solvent diffusion method, and were loaded with glucose oxidase (GOx) and catalase (CAT) enzymes. These negatively charged particles decrease micro-environmental pH, by gluconic acid production in the glucose molecules presence. Positively charged chitosan nanoparticles were prepared using ionic gelation method, and were loaded with insulin. These nanoparticles (NPs) released insulin by dissociation in acidic pH caused by the GOx activity. Following in vitro studies, in vivo evaluation of nano-complex formulations in streptozocin induced diabetic rats showed significant glycemic regulation up to 98 h after subcutaneous administration.

Nanotargeted agents: an emerging therapeutic strategy for breast cancer

Breast cancer is the most common female cancer worldwide and represents 12% of all cancer cases. Improvements in survival rates are largely attributed to improved screening and diagnosis. Conventional chemotherapy remains an important treatment option but it is beset with poor cell selectivity, serious side effects and resistance. Nanoparticle drug delivery systems bring promising opportunities to breast cancer treatment. They may improve chemotherapy by targeting drugs to tumors, generating high drug concentrations at tumors providing slow release of the drug, increased drug stability and concomitant reductions in side effects. The nanotechnology-based drug delivery approaches and the current research and application status of nano-targeted agents for breast cancer are discussed in this review to provide a basis for further study on targeted drug delivery systems.

Cell cytotoxicity, immunostimulatory and antitumor effects of lipid content of liposomal delivery platforms in cancer immunotherapies. A comprehensive in-vivo and in-vitro study

Liposome is one of the promising technologies for antigen delivery in cancer immunotherapies. It seems that the phospholipid content of liposomes can act as immunostimulatory molecules in cancer immunotherapy. In the present study, the immunological properties of different phospholipid content of liposomal antigen delivery platforms were investigated. To this aim, F1 to F4 naïve liposomes (without tumor-specific loaded antigens) of positively charged DOTAP/Cholesterol/DOPE (4/4/4 mol ratio), negatively charged DMPC/DMPG/Cholesterol/DOPE (15/2/3/5), negatively charged DSPC/DSPG/Cholesterol/DOPE (15/2/3/5) and PEGylated HSPC/mPEG2000-DSPE/Cholesterol (13/110) liposomal compositions were administered in mice bearing C26 colon carcinoma to assess tumor therapy. Moreover, In-vitro studies were conducted, including cytotoxicity assay, serum cytokines measurements, IFN-γ and IL-4 ELISpot assay, T cells subpopulation frequencies assay. The liposomes containing DOTAP and DOPE (F1 liposomes) were able to stimulate cytotoxic T lymphocytes signals such as IFN-γ secretions. In parallel, the aforementioned phospholipids stimulated secretion of IL-4 and IL-17 cytokines from T helper cells. However, these liposomes did not improve survival indices in mice. As conclusion, DOTAP and DOPE contained liposomes (F1 liposomes) stimulate a mixture of Th1 and Th2 immune responses in a tumor-specific antigens-free manner in mice bearing C26 colon carcinoma. Therefore, phospholipid composition of liposomes merits consideration in designing antigen-containing liposomes for cancer immunotherapy.

Synergistic antitumor effect of anti-PD-L1 combined with oxaliplatin on a mouse tumor model

Oxaliplatin (OXP) can change tumor microenvironment from immune-suppressive toward the immune-favorable condition. Almost all of the antitumor agents cannot totally cure cancer as monotherapy. So the current focus of cancer research became combining therapy using different treatment regimen, especially chemotherapy with checkpoint blockers. In this study, we assessed the activity of combining regimen using anti-PD-L1 with OXP in CT26 tumor-bearing BALB/c mice. We further analyzed the immune cell phenotypes in tumor site, lymph nodes, and spleen by flow cytometry analysis. Our study showed that combination therapy with OXP and anti-PD-L1 significantly increased survival in vivo and inhibited tumor growth of tumor-bearing mice. Inconsistent with better antitumor activity, our combination therapy led to an increase in tumor-infiltrating activated CD8+ T cells. In draining lymph nodes and spleen, regulatory T cells decreased significantly. Mice receiving either anti-PD-L1 or OXP alone had a larger tumor and lower survival rate in comparison with combination therapy receiving group. The time and order of administration of each component of the combination therapy affected antitumor response.

Recent development in biodegradable nanovehicle delivery system-assisted immunotherapy

A schematic illustration of BNDS biodegradation and release antigen delivery for assisting immunotherapy.

Checkpoint Inhibition: Will Combination with Radiotherapy and Nanoparticle-Mediated Delivery Improve Efficacy?

Checkpoint inhibition (CPI) has been a rare success story in the field of cancer immunotherapy. Knowledge gleaned from preclinical studies and patients that do not respond to these therapies suggest that the presence of tumor-infiltrating lymphocytes and establishment of immunostimulatory conditions, prior to CPI treatment, are required for efficacy of CPI. To this end, radiation therapy (RT) has been shown to promote immunogenic cell-death-mediated tumor-antigen release, increase infiltration and cross-priming of T cells, and decreasing immunosuppressive milieu in the tumor microenvironment, hence allowing CPI to take effect. Preclinical and clinical studies evaluating the combination of RT with CPI have been shown to overcome the resistance to either therapy alone. Additionally, nanoparticle and liposome-mediated delivery of checkpoint inhibitors has been shown to overcome toxicities and improve therapeutic efficacy, providing a rationale for clinical investigations of nanoparticle, microparticle, and liposomal delivery of checkpoint inhibitors. In this review, we summarize the preclinical and clinical studies of combined RT and CPI therapies in various cancers, and review findings from studies that evaluated nanoparticle and liposomal delivery of checkpoint inhibitors for cancer treatments.

Nanotechnology-mediated immunochemotherapy combined with docetaxel and PD-L1 antibody increase therapeutic effects and decrease systemic toxicity

Immunotherapy has exhibited enormous practice in the treatment of melanoma because of the intrinsic properties of tumor. Tumor can downmodulate immune function via multiple mechanisms such as immune checkpoint pathways. The PD-L1 monoclonal antibodies that block the PD1/PD-L1 pathway, which induced tumor cells to evade an immune attack, can delay tumor growth efficiently with inevitable disadvantages such as low selectivity and systemic toxicity. Nanomedicine is clearly an approach that holds tremendous potential for addressing the shortcomings and assisting delivery of drugs with proper biodistribution. Herein, we developed a smart nanoplatform with precisely active targeting liposome co-loaded chemotherapy and immunotherapy drugs for synergistic antitumor effects while decreasing systemic toxicity. Immunoliposomes have stable pharmaceutical properties and show a significant antitumor effect in vivo and in vitro. Cellular uptake in vitro and biodistribution in vivo demonstrated that immunoliposomes could be delivered and accumulated more in tumor tissues. These immunoliposomes exhibited effective tumor inhibition and prolonged survival time due to activation of tumor-specific CD8+ T cell and highly selective tumor killing. In addition, safety evaluation of liposomes also demonstrated their increased tumor accumulation and decreased systemic toxicity. Hence, this smart pH-sensitive nanoplatform has promising potential for clinical applications and possibly provides a well-controlled design for combination of chemotherapy with various immunotherapies for further exploration.

Exosomes derived from TRAIL-engineered mesenchymal stem cells with effective anti-tumor activity in a mouse melanoma model

Exosomes are biological nano-sized vesicles (~30-200 nm in diameter) that are produced by a wide range of cells and play several roles in cell-cell communications. These vesicles contain membrane and cytoplasmic components of producing cells. Mesenchymal stem cells (MSCs) are the ideal producer of exosomes. The secreted vesicles from MSCs are promising biological vehicles for cell-free therapy in regenerative medicine, cancer therapy and targeted delivery of therapeutic agents to the tumor cells. Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) is a promising member of the TNF family with selective effect on cancerous cells. Recent evidences showed that the membrane TRAIL-armed exosomes possess anti-tumor activity. However, the effect of in vivo administration of TRAIL-armed exosomes has not been reported so far. In the current study, mesenchymal stem cells expressing TRAIL/GFP proteins were prepared with the help of a non-viral vector based on polyethylenimine 25 kDa. Then, exosomes containing TRAIL protein (Exo-TRAIL) were isolated from the supernatant of genetically engineered MSCs and characterized. Antitumor activity of both MSC-derived exosomes and Exo-TRAIL was investigated in vitro and in vivo in three models. The results indicated that the co-injection of both Exo-TRAIL and tumor cells delayed the tumor appearance. Besides, the tumor volume/weight was efficiently decreased in tumor bearing mice. Moreover, it was shown that multi-dose injections of Exo-TRAIL reduced the tumor size while single dose treatment with Exo-TRAIL did not show significant anti-tumor activity. To conclude, these results suggested that MSC-derived Exo-TRAIL has a potential capacity for cancer treatment. [corrected].

Application of Antibody-Mediated Therapy for Treatment and Prevention of Clostridium difficile Infection

Clostridium difficile causes antibiotic- and healthcare-associated diarrhea, which is characterized by a high mortality rate (5–15%) and high recurrence rate of 20% or more. Therapeutic alternatives to antibiotics are urgently needed to improve the overall cure rate. Among these, therapeutic antibodies have shown promising results in clinical studies. Herein, the authors review current monoclonal and polyclonal anti- C. difficile antibodies that have entered the clinical development stage, either for systemic administration or by the oral route. The antibodies can be applied as monotherapy or in combination with standard-of-care to treat an infection with C. difficile or to protect from a recurrence. Bezlotoxumab is the first antibody for secondary prevention of recurrence of C. difficile infection approved by the regulatory agencies in US and Europe. The human monoclonal antibody is administered systemically to patients receiving oral standard-of–care antibiotics. Other antibodies are currently in the clinical pipeline, and some are intended for oral use. They show a good safety profile, high efficacy and low production costs, and can be considered promising therapies of the future. The most promising orally administered drug candidate is a bovine antibody from hyperimmune colostral milk, which is in an advanced clinical development stage. Which antibody will enter the market is dependent on its bioavailability at the site of infection as well as its activity against C. difficile toxins, protection against colonization and possible action on spore formation. The antibody must demonstrate a clear benefit in comparison with other available treatment options to be considered for use by clinicians.

Effect of Zuoguiwan on osteoporosis in ovariectomized rats through RANKL/OPG pathway mediated by β2AR

ETHNOPHARMACOLOGICAL RELEVANCE

The deficiency of kidney Yin is the main pathogenesis of postmenopausal osteoporosis (PMOP) according to traditional Chinese medicine (TCM). Zuoguiwan (ZGW) is among the classical prescriptions in TCM and has been applied to various diseases that are due to deficiency of kidney Yin, including osteoporosis, fractures, menopausal syndromes. However, the underlying mechanism of ZGW in treating PMOP remains poorly understood.

AIM OF THE STUDY

ZGW, a traditional Chinese prescription, has been used to nourish Yin and reinforce the kidney since ancient times. The investigation aimed to explore the mechanism of ZGW via the receptor activator of nuclear factor kappa-B ligand (RANKL)/osteoprotegerin (OPG) signaling pathway as mediated by the β2-adrenergic receptor (β2AR) in an osteoporosis rat model.

MATERIALS AND METHODS

An osteoporosis model induced by ovariectomy was established in rats. A total of 40 female Sprague-Dawley rats were randomly assigned into bilateral ovariectomy group (OVX), sham operated group (Sham), 17β-estradiol-treated positive group (E2, 25 μg/kg/d), ZGW low-dose group (ZGW-L, 2.3 g/kg/d lyophilized powder) and ZGW high-dose group (ZGW-H, 4.6 g/kg/d lyophilized powder). The serum markers of bone turnover were measured using enzyme-linked immunosorbent assay (ELISA). The morphological structure changes in bones were detected through H&E staining. Local bone mineral density (BMD) and trabecular bone microarchitecture of the right distal femur were measured and evaluated by using micro-CT. Furthermore, the mRNA and protein expressions levels of β2AR, OPG and RANKL were measured by qPCR and Western blot analysis.

RESULTS

Compared with the OVX group, ZGW groups showed significantly reduced levels of serum tartrate-resistant acid phosphatase 5b (TRACP-5b) and β-cross-linked c-telopeptide of type I collagen (β-CTX) (P ＜ 0.01), increased levels of serum bone-specific alkaline phosphatase (BALP) (P ＜ 0.01) and OPG (P ＜ 0.05), prevention of OVX-induced bone loss, and improved microarchitecture of the trabecular bone of distal femur. Moreover, ZGW mediated the osteoporosis syndrome by reducing the empty bone lacunae, promoting the ordered arrangement of trabeculae structure, and increasing the trabeculae structure thickness. Furthermore, in ZGW groups, the protein expression of OPG in the tibia was notably up-regulated (P ＜ 0.01), whereas the mRNA and protein expression of β2AR in the hippocampus (P ＜ 0.01), and the protein expressions levels of β2AR (P ＜ 0.01) and RANKL (P ＜ 0.05) in the tibia were down-regulated compared with OVX group.

CONCLUSIONS

ZGW through its protective effects, stimulates bone formation and suppresses bone resorption. The underlying mechanism of ZGW in improving perimenopausal syndrome and increasing bone mass might be attributed to the regulation of RANKL/OPG, as mediated by β2AR. Therefore, ZGW may be used as an alternative treatment for PMOP.

Liposomal CpG-ODN: An in vitro and in vivo study on macrophage subtypes responses, biodistribution and subsequent therapeutic efficacy in mice models of cancers

CpG oligodeoxynucleotides (CpG-ODN), a common immune stimulator and vaccine adjuvant, was reported to switch Tumor Associated Macrophages (TAMs) from M2 to M1 phenotype inducing anti-tumor responses. Liposomes are of the successfully applied carriers for CpG-ODN. The aim of present study was design and preparation of a liposomal formulation containing phosphodiester CpG-ODN, evaluation of its effect on macrophages responses, and subsequent antitumor responses in mice. Liposomal formulations containing phosphodiester CpG-ODN or non-CpG-ODN were prepared and characterized. MTT reduction assay in four different cell lines, uptake, arginase and iNOS activity evaluation in macrophage cell lines, biodistribution study and therapeutic anti-tumor effects of formulations in mice bearing C26 colon carcinoma or B16F0 melanoma were carried out. The size of liposomes containing CpG-ODN was ~200 nm with the encapsulation efficiency of 33%. The iNOS activity assay showed high nitric oxide (NO) level in M2 phenotype of macrophage cell lines treated by liposomes containing CpG-ODN. In mice which received liposomes containing CpG-ODN as a monotherapy, maximum tumor growth delay with remarkable survival improvement was observed compared to control groups. Biodistribution study showed the accumulation of liposomal formulation in tumor micro-environment. In conclusion, considerable anti-tumor responses observed by liposomes containing CpG-ODN was due to enhanced delivery of CpG-ODN to immune cells and subsequent initiation of anti-tumoral immune responses.

Nanoliposomes carrying HER2/neu-derived peptide AE36 with CpG-ODN exhibit therapeutic and prophylactic activities in a mice TUBO model of breast cancer

This study was designed to prepare and characterize nanoliposomal vaccine formulation encapsulating AE36 HER2/neu-derived peptide with or without CpG and evaluate the immunologic and therapeutic responses of that in BALB/c mice model of Her2 overexpressing breast cancer. AE36 was encapsulated in liposomes composed of DOTAP, DOPE and Cholesterol (DDC) or DD with. The formulations could induce both CD8+ and CD4+ responses and stimulate production of cytokines which was detected by Enzyme-linked immunospot assay (ELISpot) kits, cytotoxicity test and intracellular cytokine assay by flow cytometry. The formulation showed both therapeutic and prophylactic effects in BALB/c mice bearing Her2⁺ breast cancer. DDC+CpG showed the best effect in prophylactic study and DD+pG showed the best effect in therapeutic study, which both of them decreased the size of tumors significantly. The engineered nanoliposomes containing AE36 could be a candidate vaccine for the treatment or prophylaxis of HER2⁺ breast cancer and merits further investigation.

Application of nanostructured drug delivery systems in immunotherapy of cancer: a review

The cancer immunotherapy method uses the specificity of the immune system to provide a more effective than more conventional treatments, such as chemotherapy and radiotherapy. Immunotherapy has two main strategies (passive or active) to organize the immune system. Passive strategies use advantage of tumor-hyperpermeable cells, which have enhanced permeability and retention effects. Nanoparticles due to their better accumulation within tissues and cells of the immune system are well suitable for delivery of immune therapies such as vaccines or adjuvants. In this review, we explained application of nanotechnology in immunotherapy of cancer.

The anti-tumor effects of cordycepin-loaded liposomes on the growth of hepatoma 22 tumors in mice and human hepatoma BEL-7402 cells in culture

Liposomes have successfully been used for decades to encapsulate and protect drugs that are prone to deactivation in the body. The present study aimed to demonstrate the use of liposomes to encapsulate cordycepin, an adenosine analog that quickly loses its activity in vivo. The cordycepin-loaded liposomes were prepared by the ammonium sulfate gradient approach, and its in vitro and in vivo antitumour activities were evaluated using BEL-7402 cells and hepatocellular carcinoma H22 transplanted tumors, respectively. An MTT assay was used to observe the cytotoxicity of cells treated with cordycepin and cordycepin-loaded liposomes in vitro. High-content screening (HSC) was carried out using Hoechst 33342 to detect apoptotic cells and the ratio of cells in different cell cycle stages. The data demonstrated that both the cordycepin and the cordycepin-loaded liposomes resulted in clear cytotoxicity with IC50 values of 18.97 and 29.39 μg/mL, respectively. The latter showed significantly strong inhibitory effects on H22 tumor growth in mice, while the former did not show any inhibitory effects on tumor growth. In addition, the HSC assay showed that the cordycepin-loaded liposomes resulted in a higher rate of apoptosis than the cordycepin alone in BEL-7402 cells. Further data analysis revealed that the cells treated with cordycepin-loaded liposomes were predominately arrested at the G2/M phase (p < 0.05), while those treated with cordycepin alone were arrested in the G0/G1 phase (p < 0.05). In conclusion, these results suggest that liposomes can enhance and maintain the in vivo anti-tumor activity of cordycepin.

Targeting CD44 expressing cancer cells with anti-CD44 monoclonal antibody improves cellular uptake and antitumor efficacy of liposomal doxorubicin

Although liposomes improve the safety and pharmacokinetic properties of free drugs, they have not sufficiently enhanced the therapeutic efficacy compared to them. To address this problem, targeted therapy of tumor cells holds great promise to further enhance therapeutic index and decreases off-target effects compared with non-targeted liposomes. In the context of antibody-mediated targeted cancer therapy, we evaluated the anti-tumor activity and therapeutic efficacy of Doxil, and that of Doxil modified with a monoclonal antibody (mAb) against CD44, which is one of the most well-known surface markers associated with Cancer Stem Cells (CSCs). Flow cytometry analyses and confocal laser scanning microscopy results showed significant enhanced cellular uptake of CD44-targeted Doxil (CD44-Doxil) in CD44-positive C-26 cells compared to Doxil. However, CD44-negative NIH-3T3 cells showed a similar uptake and in vitro cytotoxicity with both CD44-Doxil and non-targeted Doxil. In BALB/c mice bearing C-26 murine carcinoma, CD44-Doxil groups exhibited significantly higher doxorubicin concentration (than Doxil) inside the tumor cells, while their circulation time and distribution profile remained comparable. CD44-Doxil at doses of either 10 or 15 mg/kg resulted in superior tumor growth inhibition and higher inclination to tumor, indicating the potential of anti-CD44 mAb targeting in therapeutic efficacy improvement. This study provides proof-of-principle for actively tumor-targeting concept and merits further investigations.