Harnessing Liposome Interactions With the Immune System for the Next Breakthrough in Cancer Drug Delivery

Nanoparticles insertion and dimerization in polymer brushes

Molecular dynamics simulations are conducted to systematically investigate the insertion of spherical nanoparticles (NPs) in polymer brushes as a function of their size, strength of their interaction with the polymers, polymer grafting density, and polymer chain length. For attractive interactions between the NPs and the polymers, the depth of NPs' penetration in the brush results from a competition between the enthalpic gain due to the favorable polymer-NP interaction and the effect of osmotic pressure resulting from displaced polymers by the NP's volume. A large number of simulations show that the average depth of the NPs increases by increasing the strength of the interaction strength. However, it decreases by increasing the NPs' diameter or increasing the polymer grafting density. While the NPs' effect on the polymer density is local, their effect on their conformations is long-ranged and extends laterally over length scales larger than the NP's size. This effect is manifested by the emergence of laterally damped oscillations in the normal component of the chains' radius of gyration. Interestingly, we found that for high enough interaction strength, two NPs dimerize in the polymer brush. The dimer is parallel to the substrate if the NPs' depth in the brush is shallow. However, the dimer is perpendicular to the substrate if the NPs' are deep in the brush. These results imply that polymer brushes can be used as a tool to localize and self-assemble NPs in polymer brushes.

Rheumatoid Arthritis Treatment Potential of Stearic Acid Nanoparticles of Quercetin in Rats

This study aims to assess the anti-inflammatory potential of stearic acid nanoparticles of quercetin in an arthritic rat model. This article describes the fabrication of solid lipid nanoparticles (SLNs) using the hot melt encapsulation method, followed by the anti-inflammatory study of SLNs and other characterizations such as FTIR, XRD, and SEM. Thirty male healthy albino rats were taken and treated with FCA to induce rheumatoid arthritis. Quercetin loading of quercetin to stearic acid was confirmed by FTIR. The efficacy of quercetin-loaded SLNs to reduce inflammation was evaluated with the help of inflammatory biomarker levels. Quercetin-loaded stearic acid nanoparticles were successfully prepared by using a hot melt encapsulation method. Their average size and zeta potential were 100 nm and -25 mV, respectively. Rheumatoid arthritis was significantly (p < 0.001) reduced in the quercetin-loaded SLN group, as indicated by finding out the reduced levels of inflammatory mediators such as tumor necrosis factor (TNF-α) and rheumatoid factor. Quercetin-loaded stearic acid nanoparticles were found to be potentially effective in treating RA.

Protein corona formation on lipidic nanocapsules: Influence of the interfacial PEG repartition

The parameters currently used for characterization of nanoparticles, such as size and zeta potential, were not able to reflect the performance of a nanocarrier in the biological environment. Therefore, more thorough in vitro characterization is required to predict their behavior in vivo, where nanoparticles acquire a new biological identity due to interactions with biomolecules. In this present study, we performed in vitro characterization in biological fluids for lipid nanocapsules (LNCs) with varying means sizes (50 nm and 100 nm), different electrical surface charges and different Poly Ethylene Glycol (PEG) compositions. Then, different methods were applied to show the impact of the protein corona formation on LNCs. Even if all formulations attached to plasmatic proteins, a higher thickness of corona and highest protein binding was observed for certain LNC50 formulations. A better knowledge of the phenomenon of protein adsorption over NPs in the plasmatic media is a cornerstone of clinical translation. In fact, after short blood circulation time, it is not the initially designed nanoparticle but the complex nanoparticle bearing its protein corona which circulates to reach its target.

Inhibition of c-Rel expression in myeloid and lymphoid cells with distearoyl -phosphatidylserine (DSPS) liposomal nanoparticles encapsulating therapeutic siRNA

c-Rel, a member of the nuclear factor kappa B (NF-κB) family, is preferentially expressed by immune cells and is known to regulate inflammation, autoimmune diseases and cancer. However, there is a lack of therapeutic intervention to specifically inhibit c-Rel in immune cells. Recent success with Pfizer and Moderna mRNA lipid-encapsulated vaccines as well as FDA approved medicines based on siRNA prompted us to test a lipid nanoparticle-based strategy to silence c-Rel in immune cells. Specifically, we encapsulated c-Rel-targeting siRNA into distearoyl-phosphatidylserine (DSPS)-containing nanoparticles. DSPS is a saturated phospholipid that serves as the "eat-me" signal for professional phagocytes such as macrophages and neutrophils of the immune system. We demonstrated here that incorporation of DSPS in liposome nanoparticles (LNP) improved their uptake by immune cells. LNP containing high concentrations of DSPS were highly effective to transfect not only macrophages and neutrophils, but also lymphocytes, with limited toxicity to cells. However, LNP containing low concentrations of DSPS were more effective to transfect myeloid cells than lymphoid cells. Importantly, DSPS-LNP loaded with a c-Rel siRNA were highly effective to inhibit c-Rel expression in several professional phagocytes tested, which lasted for several days. Taken together, our results suggest that DSPS-LNP armed with c-Rel siRNA could be exploited to target immune cells to limit the development of inflammatory diseases or cancer caused by c-Rel upregulation. In addition, this newly developed DSPS-LNP system may be further tested to encapsulate and deliver other small molecule drugs to immune cells, especially macrophages, neutrophils, and lymphocytes for the treatment of diseases.

Multimodal imaging distribution assessment of a liposomal antibiotic in an infectious disease model

Liposomes are promising targeted drug delivery systems with the potential to improve the efficacy and safety profile of certain classes of drugs. Though attractive, there are unique analytical challenges associated with the development of liposomal drugs including human dose prediction given these are multi-component drug delivery systems. In this study, we developed a multimodal imaging approach to provide a comprehensive distribution assessment for an antibacterial drug, GSK2485680, delivered as a liposomal formulation (Lipo680) in a mouse thigh model of bacterial infection to support human dose prediction. Positron emission tomography (PET) imaging was used to track the in vivo biodistribution of Lipo680 over 48 h post-injection providing a clear assessment of the uptake in various tissues and, importantly, the selective accumulation at the site of infection. In addition, a pharmacokinetic model was created to evaluate the kinetics of Lipo680 in different tissues. Matrix-assisted laser desorption/ionization (MALDI) imaging mass spectrometry (IMS) was then used to quantify the distribution of GSK2485680 and to qualitatively assess the distribution of a liposomal lipid throughout sections of infected and non-infected hindlimb tissues at high spatial resolution. Through the combination of both PET and MALDI IMS, we observed excellent correlation between the Lipo680-radionuclide signal detected by PET with the GSK2485680 and lipid component signals detected by MALDI IMS. This multimodal translational method can reduce drug attrition by generating comprehensive biodistribution profiles of drug delivery systems to provide mechanistic insight and elucidate safety concerns. Liposomal formulations have potential to deliver therapeutics across a broad array of different indications, and this work serves as a template to aid in delivering future liposomal drugs to the clinic.

Nanomedicine approaches for treatment of hematologic and oncologic malignancies

Cancer is a leading cause of death worldwide. Nowadays, the therapies are inadequate and spur demand for improved technologies. Rapid growth in nanotechnology and novel nanomedicine products represents an opportunity to achieve sophisticated targeting strategies and multi-functionality. Nanomedicine is increasingly used to develop new cancer diagnosis and treatment methods since this technology can modulate the biodistribution and the target site accumulation of chemotherapeutic drugs, thereby reducing their toxicity. Cancer nanotechnology and cancer immunotherapy are two parallel themes that have emerged over the last few decades while searching for a cure for cancer. Immunotherapy is revolutionizing cancer treatment, as it can achieve unprecedented responses in advanced-stage patients, including complete cures and long-term survival. A deeper understanding of the human immune system allows the establishment of combination regimens in which immunotherapy is combined with other treatment modalities (as in the case of the nanodrug Ferumoxytol). Furthermore, the combination of gene therapy approaches with nanotechnology that aims to silence or express cancer-relevant genes via one-time treatment is gradually progressing from bench to bedside. The most common example includes lipid-based nanoparticles that target VEGF-Α and KRAS pathways. This review focuses on nanoparticle-based platforms utilized in recent advances aiming to increase the efficacy of currently available cancer therapies. The insights provided and the evidence obtained in this paper indicate a bright future ahead for immuno-oncology applications of engineering nanomedicines.

Nanoparticle personalized biomolecular corona: implications of pre-existing conditions for immunomodulation and cancer

Nanoparticles (NPs) have demonstrated great promise as immunotherapies for applications ranging from cancer, autoimmunity, and infectious disease. Upon encountering biological fluids, NPs rapidly adsorb biomolecules, forming the "biomolecular corona" (BC), and the altered character of NPs due to their newly acquired biological identity can impact their in vivo fate. Recently, it has been shown that the NP-BC is person-specific, and even minute differences in the biomolecule composition can give rise to altered immune recognition, cellular interactions, pharmacokinetics, and biodistribution. Given the current rise in the development of NP-based therapeutics, it is of utmost importance to better understand how pre-existing conditions, that result in the formation of a personalized BC, can be leveraged to aid in the prediction of the therapeutic outcomes of NPs. In this minireview, we will discuss the formation of the BC, implications of the BC for NP-biological interactions, and its clinical importance in the context of immunomodulation and cancer therapeutics.

Microfluidic Digital Quantitative PCR to Measure Internal Cargo of Individual Liposomes

Lipid nanoparticles serve as drug delivery vehicles for biopharmaceutical products. The lipid membrane shields internal nucleic-acid drug cargo from enzymatic degradation and facilitates cellular uptake of the drug. However, existing methods to assess drug loading within liposomes are limited to averaged bulk measurements, which obscures heterogeneity of the biopharmaceutical formulation. This report describes the development of a single-liposome analysis method to measure copy numbers of DNA within liposomes and assess population heterogeneity. This novel measurement was achieved by integrating two orthogonal polymerase chain reaction (PCR) techniques─digital PCR (dPCR) and quantitative PCR (qPCR)─within a single microfluidic assay. The dPCR dimension quantified liposomes to validate their capture in the single-liposome analysis regime. The qPCR dimension quantified DNA copy numbers packaged within each liposome. The ability of digital quantitative PCR (dqPCR) to analyze large numbers of individual liposomes in parallel revealed significant population heterogeneity, which could not be obtained from standard bulk analysis methods. Our innovative measurement of internal DNA cargo from single liposomes has the potential to inform liposome synthesis procedures and create more uniform liposomal biopharmaceutical formulations to enhance drug safety and efficacy.

Effect of Particle Carriers for Intraperitoneal Drug Delivery on the Course of Ovarian Cancer and Its Immune Microenvironment in a Mouse Model

Novel treatment strategies are needed to provide a better prognosis for ovarian cancer. For this purpose, the current study was designed to evaluate the effects of different types of particle drug carriers on tumor response and on the tumor immune microenvironment (TME) after intraperitoneal (IP) administration in a murine tumor model. Mice with ID8-fLuc ovarian cancer were injected IP with pegylated liposomes, hydroxyapatite, polystyrene, poly(lactic-co-glycolic acid) (PLGA) and calcium carbonate (CaCO₃) microparticles to evaluate the effect of the candidate carriers without drugs. Our results show that several types of microparticle drug carriers caused hyperproliferation of the tumor when injected IP, as reflected in a reduced survival or an accelerated onset of ascites. Alterations of the product formulation of CaCO₃ microparticles could result in less hyperproliferation. The hyperproliferation caused by CaCO₃ and PLGA was largely driven by a strong innate immune suppression. A combination with chemotherapy was not able to sufficiently counteract the tumor progression caused by the drug carriers. This research points towards the importance of evaluating a drug carrier before using it in a therapeutic setting, since drug carriers themselves can detrimentally influence tumor progression and immune status of the TME. However, it remains to be determined whether the hyperproliferation in this model will be of relevance in other cancer models or in humans.

Recent Progress in Nanostructured Smart Drug Delivery Systems for Cancer Therapy: A Review

Traditional treatment approaches for cancer involve intravenous chemotherapy or other forms of drug delivery. These therapeutic measures suffer from several limitations such as nonspecific targeting, poor biodistribution, and buildup of drug resistances. However, significant technological advancements have been made in terms of superior modes of drug delivery over the last few decades. Technical capability in analyzing the molecular mechanisms of tumor biology, nanotechnology─particularly the development of biocompatible nanoparticles, surface modification techniques, microelectronics, and material sciences─has increased. As a result, a significant number of nanostructured carriers that can deliver drugs to specific cancerous sites with high efficiency have been developed. This particular maneuver that enables the introduction of a therapeutic nanostructured substance in the body by controlling the rate, time, and place is defined as the nanostructured drug delivery system (NDDS). Because of their versatility and ability to incorporate features such as specific targeting, water solubility, stability, biocompatibility, degradability, and ability to reverse drug resistance, they have attracted the interest of the scientific community, in general, and nanotechnologists as well as biomedical scientists. To keep pace with the rapid advancement of nanotechnology, specific technical aspects of the recent NDDSs and their prospects need to be reported coherently. To address these ongoing issues, this review article provides an overview of different NDDSs such as lipids, polymers, and inorganic nanoparticles. In addition, this review also reports the challenges of current NDDSs and points out the prospective research directions of these nanocarriers. From our focused review, we conclude that still now the most advanced and potent field of application for NDDSs is lipid-based, while other significantly potential fields include polymer-based and inorganic NDDSs. However, despite the promises, challenges remain in practical implementations of such NDDSs in terms of dosage and stability, and caution should be exercised regarding biocompatibility of materials. Considering these aspects objectively, this review on NDDSs will be particularly of interest for small-to-large scale industrial researchers and academicians with expertise in drug delivery, cancer research, and nanotechnology.

Revisiting the outstanding questions in cancer nanomedicine with a future outlook

The field of cancer nanomedicine has been fueled by the expectation of mitigating the inefficiencies and life-threatening side effects of conventional chemotherapy. Nanomedicine proposes to utilize the unique nanoscale properties of nanoparticles to address the most pressing questions in cancer treatment and diagnosis. The approval of nano-based products in the 1990s inspired scientific explorations in this direction. However, despite significant progress in the understanding of nanoscale properties, there are only very few success stories in terms of substantial increase in clinical efficacy and overall patient survival. All existing paradigms such as the concept of enhanced permeability and retention (EPR), the stealth effect and immunocompatibility of nanomedicine have been questioned in recent times. In this review we critically examine impediments posed by biological factors to the clinical success of nanomedicine. We put forth current observations on critical outstanding questions in nanomedicine. We also provide the promising side of cancer nanomedicine as we move forward in nanomedicine research. This would provide a future direction for research in nanomedicine and inspire ongoing investigations.

L-asparaginase mediated therapy in L-asparagine auxotrophic cancers: A review

Microbial L-asparaginase is the most effective first-line therapeutic used in the treatment protocols of paediatric and adult leukemia. Leukemic cell's auxotrophy for L-asparagine is exploited as a therapeutic strategy to mediate cell death through metabolic blockade of L-asparagine using L-asparaginase. Escherichia coli and Erwinia chrysanthemi serve as the major enzyme deriving sources accepted in clinical practise and the enzyme has bestowed improvements in patient outcomes over the last 40 years. However, an array of side effects generated by the native enzymes due to glutamine co-catalysis and short serum stays augmenting frequent dosages, intended a therapeutic switch towards the development of biobetter alternatives for the enzyme including the formulations resulting in sustained local depletion of L-asparagine. In addition, the treatment with L-asparaginase in few cancer types has proven to elicit drug-induced cytoprotective autophagy mechanisms and therefore warrants concern. Although the off-target glutamine hydrolysis has been viewed in contributing the drug-induced secondary responses in cells deficient with asparagine synthetase machinery, the beneficial role of glutaminase-asparaginase in proliferative regulation of asparagine prototrophic cells has been looked forward. The current review provides an overview on the enzyme's clinical applications in leukemia and possible therapeutic implications in other solid tumours, recent advancements in drug formulations, and discusses the aspects of two-sided roles of glutaminase-asparaginases and drug-induced cytoprotective autophagy mechanisms.

Strategies for Liposome Drug Delivery Systems to Improve Tumor Treatment Efficacy

In the advancement of tumor therapy, in addition to the search for new antitumor compounds, the development of nano-drug delivery systems has opened up new pathways for tumor treatment by addressing some of the limitations of traditional drugs. Liposomes have received much attention for their high biocompatibility, low toxicity, high inclusivity, and improved drug bioavailability. They are one of the most studied nanocarriers, changing the size and surface characteristics of liposomes to better fit the tumor environment by taking advantage of the unique pathophysiology of tumors. They can also be designed as tumor targeting drug delivery vehicles for the precise delivery of active drugs into tumor cells. This paper reviews the current development of liposome formulations, summarizes the characterization methods of liposomes, and proposes strategies to improve the effectiveness of tumor treatment. Finally, it provides an outlook on the challenges and future directions of the field. Graphical abstract.

Liposome Photosensitizer Formulations for Effective Cancer Photodynamic Therapy

Photodynamic therapy (PDT) is a promising non-invasive strategy in the fight against that which circumvents the systemic toxic effects of chemotherapeutics. It relies on photosensitizers (PSs), which are photoactivated by light irradiation and interaction with molecular oxygen. This generates highly reactive oxygen species (such as ¹O₂, H₂O₂, O₂, ·OH), which kill cancer cells by necrosis or apoptosis. Despite the promising effects of PDT in cancer treatment, it still suffers from several shortcomings, such as poor biodistribution of hydrophobic PSs, low cellular uptake, and low efficacy in treating bulky or deep tumors. Hence, various nanoplatforms have been developed to increase PDT treatment effectiveness and minimize off-target adverse effects. Liposomes showed great potential in accommodating different PSs, chemotherapeutic drugs, and other therapeutically active molecules. Here, we review the state-of-the-art in encapsulating PSs alone or combined with other chemotherapeutic drugs into liposomes for effective tumor PDT.

Protein-Based Nanohydrogels for Bioactive Delivery

Hydrogels possess a unique three-dimensional, cross-linked network of polymers capable of absorbing large amounts of water and biological fluids without dissolving. Nanohydrogels (NGs) or nanogels are composed of diverse types of polymers of synthetic or natural origin. Their combination is bound by a chemical covalent bond or is physically cross-linked with non-covalent bonds like electrostatic interactions, hydrophobic interactions, and hydrogen bonding. Its remarkable ability to absorb water or other fluids is mainly attributed to hydrophilic groups like hydroxyl, amide, and sulphate, etc. Natural biomolecules such as protein- or peptide-based nanohydrogels are an important category of hydrogels which possess high biocompatibility and metabolic degradability. The preparation of protein nanohydrogels and the subsequent encapsulation process generally involve use of environment friendly solvents and can be fabricated using different proteins, such as fibroins, albumin, collagen, elastin, gelatin, and lipoprotein, etc. involving emulsion, electrospray, and desolvation methods to name a few. Nanohydrogels are excellent biomaterials with broad applications in the areas of regenerative medicine, tissue engineering, and drug delivery due to certain advantages like biodegradability, biocompatibility, tunable mechanical strength, molecular binding abilities, and customizable responses to certain stimuli like ionic concentration, pH, and temperature. The present review aims to provide an insightful analysis of protein/peptide nanohydrogels including their preparation, biophysiochemical aspects, and applications in diverse disciplines like in drug delivery, immunotherapy, intracellular delivery, nutraceutical delivery, cell adhesion, and wound dressing. Naturally occurring structural proteins that are being explored in protein nanohydrogels, along with their unique properties, are also discussed briefly. Further, the review also covers the advantages, limitations, overview of clinical potential, toxicity aspects, stability issues, and future perspectives of protein nanohydrogels.

Potential Use of Exosomes as Diagnostic Biomarkers and in Targeted Drug Delivery: Progress in Clinical and Preclinical Applications

Exosomes are cell-derived vesicles containing heterogeneous active biomolecules such as proteins, lipids, mRNAs, receptors, immune regulatory molecules, and nucleic acids. They typically range in size from 30 to 150 nm in diameter. An exosome's surfaces can be bioengineered with antibodies, fluorescent dye, peptides, and tailored for small molecule and large active biologics. Exosomes have enormous potential as a drug delivery vehicle due to enhanced biocompatibility, excellent payload capability, and reduced immunogenicity compared to alternative polymeric-based carriers. Because of active targeting and specificity, exosomes are capable of delivering their cargo to exosome-recipient cells. Additionally, exosomes can potentially act as early stage disease diagnostic tools as the exosome carries various protein biomarkers associated with a specific disease. In this review, we summarize recent progress on exosome composition, biological characterization, and isolation techniques. Finally, we outline the exosome's clinical applications and preclinical advancement to provide an outlook on the importance of exosomes for use in targeted drug delivery, biomarker study, and vaccine development.

Life after Cell Death-Survival and Survivorship Following Chemotherapy

Simple Summary

Treatment of aggressive cancers often relies on chemotherapy. This treatment has improved survival rates, but while effective at killing cancer cells, inevitably it also kills or alters the function of others. While many of the known effects are transient and resolve after treatment, as survival rates increase, so does our understanding of the long-term health costs that accompany cancer survivors. Here we provide an overview of common long-term morbidities known to be caused by conventional chemotherapy, including the risk of relapse, but more importantly, the cost of quality of life experienced, especially by those who have cancer in early life. We aim to highlight the importance of the development of targeted therapies to replace the use of conventional chemotherapy, but also that of treating the patients along with the disease to enable not only longer but also healthier life after cancer.

Abstract

To prevent cancer cells replacing and outnumbering their functional somatic counterparts, the most effective solution is their removal. Classical treatments rely on surgical excision, chemical or physical damage to the cancer cells by conventional interventions such as chemo- and radiotherapy, to eliminate or reduce tumour burden. Cancer treatment has in the last two decades seen the advent of increasingly sophisticated therapeutic regimens aimed at selectively targeting cancer cells whilst sparing the remaining cells from severe loss of viability or function. These include small molecule inhibitors, monoclonal antibodies and a myriad of compounds that affect metabolism, angiogenesis or immunotherapy. Our increased knowledge of specific cancer types, stratified diagnoses, genetic and molecular profiling, and more refined treatment practices have improved overall survival in a significant number of patients. Increased survival, however, has also increased the incidence of associated challenges of chemotherapy-induced morbidity, with some pathologies developing several years after termination of treatment. Long-term care of cancer survivors must therefore become a focus in itself, such that along with prolonging life expectancy, treatments allow for improved quality of life.

Specificity of pharmacokinetic modeling of nanomedicines

Nanomedicines have been developed for more than four decades to optimize the pharmacokinetics (PK) of drugs, especially absorption, distribution, and stability in vivo. Unfortunately, only a few drug products have reached the market. One reason among others is the lack of proper PK modeling and evaluation, which impedes the optimization of these promising drug delivery systems. In this review, we discuss the specificity of nanomedicines and propose key parameters to take into account for future accurate PK evaluation of nanomedicine. We believe that this could help these innovative drug products to reach to market and change the fate of many diseases.

Clinical Experience and Recent Advances in the Development of Listeria-Based Tumor Immunotherapies

The promise of tumor immunotherapy to significantly improve survival in patients who are refractory to long-standing therapies, such as chemotherapy and radiation, is now being realized. While immune checkpoint inhibitors that target PD-1 and CTLA-4 are leading the charge in clinical efficacy, there are a number of other promising tumor immunotherapies in advanced development such as Listeria-based vaccines. Due to its unique life cycle and ability to induce robust CTL responses, attenuated strains of Listeria monocytogenes (Lm) have been utilized as vaccine vectors targeting both infectious disease and cancer. In fact, preclinical studies in a multitude of cancer types have found Listeria-based vaccines to be highly effective at activating anti-tumor immunity and eradicating tumors. Several clinical trials have now recently reported their results, demonstrating promising efficacy against some cancers, and unique challenges. Development of the Lm-based immunotherapies continues with discovery of improved methods of attenuation, novel uses, and more effective combinatorial regimens. In this review, we provide a brief background of Listeria monocytogenes as a vaccine vector, discuss recent clinical experience with Listeria-based immunotherapies, and detail the advancements in development of improved Listeria-based vaccine platforms and in their utilization.

Immunologically Inert Nanostructures as Selective Therapeutic Tools in Inflammatory Diseases

The current therapies based on immunosuppressant or new biologic drugs often show some limitations in term of efficacy and applicability, mainly because of their inadequate targeting and of unwanted adverse reactions they generate. To overcome these inherent problems, in the last decades, innovative nanocarriers have been developed to encapsulate active molecules and offer novel promising strategies to efficiently modulate the immune system. This review provides an overview of how it is possible, exploiting the favorable features of nanocarriers, especially with regard to their immunogenicity, to improve the bioavailability of novel drugs that selectively target immune cells in the context of autoimmune disorders and inflammatory diseases. A focus is made on nanoparticles that selectively target neutrophils in inflammatory pathologies.

Nanomaterials-Mediated Immunomodulation for Cancer Therapeutics

Immunotherapy holds great promise in overcoming the limitations of conventional regimens for cancer therapeutics. There is growing interest among researchers and clinicians to develop novel immune-strategies for cancer diagnosis and treatment with better specificity and lesser adversity. Immunomodulation-based cancer therapies are rapidly emerging as an alternative approach that employs the host’s own defense mechanisms to recognize and selectively eliminate cancerous cells. Recent advances in nanotechnology have pioneered a revolution in the field of cancer therapy. Several nanomaterials (NMs) have been utilized to surmount the challenges of conventional anti-cancer treatments like cytotoxic chemotherapy, radiation, and surgery. NMs offer a plethora of exceptional features such as a large surface area to volume ratio, effective loading, and controlled release of active drugs, tunable dimensions, and high stability. Moreover, they also possess the inherent property of interacting with living cells and altering the immune responses. However, the interaction between NMs and the immune system can give rise to unanticipated adverse reactions such as inflammation, necrosis, and hypersensitivity. Therefore, to ensure a successful and safe clinical application of immunomodulatory nanomaterials, it is imperative to acquire in-depth knowledge and a clear understanding of the complex nature of the interactions between NMs and the immune system. This review is aimed at providing an overview of the recent developments, achievements, and challenges in the application of immunomodulatory nanomaterials (iNMs) for cancer therapeutics with a focus on elucidating the mechanisms involved in the interplay between NMs and the host’s immune system.

Complex Factors and Challenges that Affect the Pharmacology, Safety and Efficacy of Nanocarrier Drug Delivery Systems

Major developments in nanomedicines, such as nanoparticles (NPs), nanosomes, and conjugates, have revolutionized drug delivery capabilities over the past four decades. Although nanocarrier agents provide numerous advantages (e.g., greater solubility and duration of systemic exposure) compared to their small-molecule counterparts, there is considerable inter-patient variability seen in the systemic disposition, tumor delivery and overall pharmacological effects (i.e., anti-tumor efficacy and unwanted toxicity) of NP agents. This review aims to provide a summary of fundamental factors that affect the disposition of NPs in the treatment of cancer and why they should be evaluated during preclinical and clinical development. Furthermore, this chapter will highlight some of the translational challenges associated with elements of NPs and how these issues can only be addressed by detailed and novel pharmacology studies.

Biomedical nanomaterials for immunological applications: ongoing research and clinical trials

Research efforts on nanomaterial-based therapies for the treatment of autoimmune diseases and cancer have spiked and have made rapid progress over the past years. Nanomedicine has been shown to contribute significantly to overcome current therapeutic limitations, exhibiting advantages compared to conventional therapeutics, such as sustained drug release, delayed drug degradation and site-specific drug delivery. Multiple nanodrugs have reached the clinic, but translation is often hampered by either low targeting efficiency or undesired side effects. Nanomaterials, and especially inorganic nanoparticles, have gained criticism due to their potential toxic effects, including immunological alterations. However, many strategies have been attempted to improve the therapeutic efficacy of nanoparticles and exploit their unique properties for the treatment of inflammation and associated diseases. In this review, we elaborate on the immunomodulatory effects of nanomaterials, with a strong focus on the underlying mechanisms that lead to these specific immune responses. Nanomaterials to be discussed include inorganic nanoparticles such as gold, silica and silver, as well as organic nanomaterials such as polymer-, dendrimer-, liposomal- and protein-based nanoparticles. Furthermore, various approaches for tuning nanomaterials in order to enhance their efficacy and attenuate their immune stimulation or suppression, with respect to the therapeutic application, are described. Additionally, we illustrate how the acquired insights have been used to design immunotherapeutic strategies for a variety of diseases. The potential of nanomedicine-based therapeutic strategies in immunotherapy is further illustrated by an up to date overview of current clinical trials. Finally, recent efforts into enhancing immunogenic cell death through the use of nanoparticles are discussed.

Potent in vivo antimalarial activity of water-soluble artemisinin nano-preparations

Artemisinin is a remarkable compound whose derivatives and combinations with multiple drugs have been utilized at the forefront of malaria treatment. However, the inherent issues of the parent compound such as poor bioavailability, short serum half-life, and high first-pass metabolism partially limit further applications of this drug. In this study, we enhanced the aqueous phase solubility of artemisinin by encapsulating it in two nanocarriers based on the polymer polycaprolactone (ART-PCL) and lipid-based Large Unilamellar Vesicles (ART-LIPO) respectively. Both nanoformulations exhibit in vitro parasite killing activity against Plasmodium falciparum with the ART-LIPO performing at comparable efficacy to the control drug solubilized in ethanol. These water-soluble formulations showed potent in vivo antimalarial activity as well in the mouse model of malaria at equivalent doses of the parent drug. Additionally, the artemisinin-PCL nanoformulation used in combination with either pyrimethamine or chloroquine increased the survival of the Plasmodium berghei infected mice for more than 34 days and effectively cured the mice of the infection. We highlight the potential for polymer and liposome-based nanocarriers in improving not only the aqueous phase solubility of artemisinin but also concomitantly retaining its therapeutic efficacy in vivo as well.

Extracellular Vesicles - Advanced Nanocarriers in Cancer Therapy: Progress and Achievements

Extracellular vesicles (EVs) are a class of cell-derived, lipid bilayer membrane composed vesicles, and some of them such as exosomes and ectosomes have been proven, playing remarkable roles in transmitting intercellular information, and being involved in each property of cell physiological activities. Nowadays, EVs are considered as potential nanocarriers which could partially resolve the problems of current chemotherapy because of their distinctive advantages. As endogenous membrane encompassed vesicles with nanosize, EVs are able to pass through the natural barriers with prolonged circulation time in vivo and have intrinsic cell targeting properties, they are less toxic, and less immunogenic. Recently, studies focusing on EV-based drug delivery system for cancer therapy have exploded dramatically. This review aims to outline the current applications of EVs as potential nanosized drug carriers in cancer therapy. Firstly, the characteristics and biofunctions of each EV subtype are described. Then the variety of therapeutic cargoes, the loading methods, and the targeting strategy of engineered EVs are emphatically introduced. Thereafter the pros and cons of EVs applied as therapeutic carriers, as well as the future prospects in this field, are discussed.

Immunological and Toxicological Considerations for the Design of Liposomes

Liposomes hold great potential as gene and drug delivery vehicles due to their biocompatibility and modular properties, coupled with the major advantage of attenuating the risk of systemic toxicity from the encapsulated therapeutic agent. Decades of research have been dedicated to studying and optimizing liposomal formulations for a variety of medical applications, ranging from cancer therapeutics to analgesics. Some effort has also been made to elucidate the toxicities and immune responses that these drug formulations may elicit. Notably, intravenously injected liposomes can interact with plasma proteins, leading to opsonization, thereby altering the healthy cells they come into contact with during circulation and removal. Additionally, due to the pharmacokinetics of liposomes in circulation, drugs can end up sequestered in organs of the mononuclear phagocyte system, affecting liver and spleen function. Importantly, liposomal agents can also stimulate or suppress the immune system depending on their physiochemical properties, such as size, lipid composition, pegylation, and surface charge. Despite the surge in the clinical use of liposomal agents since 1995, there are still several drawbacks that limit their range of applications. This review presents a focused analysis of these limitations, with an emphasis on toxicity to healthy tissues and unfavorable immune responses, to shed light on key considerations that should be factored into the design and clinical use of liposomal formulations.

Translational considerations in nanomedicine: The oncology perspective

Nanoparticles can provide effective control of the release rate and tissue distribution of their drug payload, leading to major pharmacokinetic and pharmacodynamic changes vis-à-vis the conventional administration of free drugs. In the last two decades, we have witnessed major progress in the synthesis and characterization of engineered nanoparticles for imaging and treatment of cancers, resulting in the approval for clinical use of several products and in new and promising approaches. Despite these advances, clinical applications of nanoparticle-based therapeutic and imaging agents remain limited due to biological, immunological, and translational barriers. There is a need to make high impact advances toward translation. In this review, we address biological, toxicological, immunological, and translational aspects of nanomedicine and discuss approaches to move the field forward productively. Overcoming these barriers may dramatically improve the development potential and role of nanomedicines in the oncology field and help meet the high expectations.

Repurposing amino-bisphosphonates by liposome formulation for a new role in cancer treatment

Amino-bisphosphonates (N-BPs) have been commercially available for over four decades and are used for the treatment of osteoporosis, Paget's disease, hypercalcemia of malignancy, and bone metastases derived from various cancer types. Zoledronate and alendronate, two of the most potent N-BPs, have demonstrated direct tumoricidal activity on tumor cells and immune modulatory effects on myeloid cells and T cells in vitro and in animal models of cancer. However, the rapid renal clearance and sequestration in mineral bone of these drugs in free form severely limit their systemic exposure and applications in cancer patients. Reformulation of N-BPs by encapsulation in liposomal nanoparticles addresses these pharmacokinetic barriers, and liposomal zoledronate and alendronate formulations have been found to increase the anticancer efficacy of cytotoxic chemotherapies and adoptive T cell immunotherapies in murine cancer models. Herein, we review the differences in pharmacology between N-BPs versus non-N-BPs (e.g., clodronate), free versus liposomal N-BP formulations, and targeted versus non-targeted liposomal N-BPs, and the clinical and preclinical evidence supporting a role for liposomal N-BPs in the treatment of cancer. We propose that pegylated liposomal alendronate (PLA) has the most potential for clinical translation based on favorable therapeutic index, ability to passively target and accumulate in tumors, proven biocompatibility of the liposome carrier, and preclinical anticancer efficacy.

Nanomedicines - Tiny particles and big challenges

After decades of research, nanotechnology has been used in a broad array of biomedical products including medical devices, drug products, drug substances, and pharmaceutical-grade excipients. But like many great achievements in science, there is a fine balance between the risks and opportunities of this new technology. Some materials and surface structures in the nanosize range can exert unexpected toxicities and merit a more detailed safety assessment. Regulatory agencies such as the United States Food and Drug Administration or the European Medicines Agency have started dealing with the potential risks posed by nanomaterials. Considering that a thorough characterization is one of the key aspects of controlling such risks this review presents the regulatory background of nanosafety assessment and provides some practical advice on how to characterize nanomaterials and drug formulations. Further, the challenges of how to maintain and monitor pharmaceutical quality through a highly complex production processes will be discussed.

Challenges and pitfalls in the development of liposomal delivery systems for cancer therapy

Despite considerable advances in the application of liposomal drug delivery systems in cancer treatment, the clinical application of liposomal formulations has been limited by many factors. It seems that there is a wide gap between results of experimental studies and clinical application of liposomes. In this review, we discuss barriers which limit the translation of liposomal delivery systems in cancer therapy. The main focus of this review will be on differences between preclinical and clinical studies and potential approaches to overcome the main pitfalls in the clinical application of liposomal delivery systems.

Liposomes of Quantum Dots Configured for Passive and Active Delivery to Tumor Tissue

The majority of developed and approved anticancer nanomedicines have been designed to exploit the dogma of the enhanced permeability and retention (EPR) effect, which is based on the leakiness of the tumor's blood vessels accompanied by impeded lymphatic drainage. However, the EPR effect has been under scrutiny recently because of its variable manifestation across tumor types and animal species and its poor translation to human cancer therapy. To facilitate the EPR effect, systemically injected NPs should overcome the obstacle of rapid recognition and elimination by the mononuclear phagocyte system (MPS). We hypothesized that circulating monocytes, major cells of the MPS that infiltrate the tumor, may serve as an alternative method for achieving increased tumor accumulation of NPs, independent of the EPR effect. We describe here the accumulation of liposomal quantum dots (LipQDs) designed for active delivery via monocytes, in comparison to LipQDs designed for passive delivery (via the EPR effect), following IV administration in a mammary carcinoma model. Hydrophilic QDs were synthesized and entrapped in functionalized liposomes, conferring passive ("stealth" NPs; PEGylated, neutral charge) and active (monocyte-mediated delivery; positively charged) properties by differing in their lipid composition, membrane PEGylation, and charge (positively, negatively, and neutrally charged). The various physicochemical parameters affecting the entrapment yield and optical stability were examined in vitro and in vivo. Biodistribution in the blood, various organs, and in the tumor was determined by the fluorescence intensity and Cd analyses. Following the treatment of animals (intact and mammary-carcinoma-bearing mice) with disparate formulations of LipQDs (differing by their lipid composition, neutrally and positively charged surfaces, and hydrophilic membrane), we demonstrate comparable tumor uptake of QDs delivered by the passive and the active routes (mainly by Ly-6C^hi monocytes). Our findings suggest that entrapping QDs in nanosized liposomal formulations, prepared by a new facile method, imparts superior structural and optical stability and a suitable biodistribution profile leading to increased tumor uptake of fluorescently stable QDs.