Targeted Cancer Immunotherapy: Nanoformulation Engineering and Clinical Translation

Nanomaterials as Microglia Modulators in the Treatment of Central Nervous System Disorders

Microglia play a pivotal role in the central nervous system (CNS) homeostasis, acting as housekeepers and defenders of the surrounding environment. These cells can elicit their functions by shifting into two main phenotypes: pro-inflammatory classical phenotype, M1, and anti-inflammatory alternative phenotype, M2. Despite their pivotal role in CNS homeostasis, microglia phenotypes can influence the development and progression of several CNS disorders such as Alzheimer's disease, Parkinson's disease, amyotrophic lateral sclerosis, multiple sclerosis, ischemic stroke, traumatic brain injuries, and even brain cancer. It is thus clear that the possibility of modulating microglia activation has gained attention as a therapeutic tool against many CNS pathologies. Nanomaterials are an unprecedented tool for manipulating microglia responses, in particular, to specifically target microglia and elicit an in situ immunomodulation activity. This review focuses the discussion on two main aspects: analyzing the possibility of using nanomaterials to stimulate a pro-inflammatory response of microglia against brain cancer and introducing nanostructures able to foster an anti-inflammatory response for treating neurodegenerative disorders. The final aim is to stimulate the analysis of the development of new microglia nano-immunomodulators, paving the way for innovative and effective therapeutic approaches for the treatment of CNS disorders.

Therapeutic Applications of Nanomedicine: Recent Developments and Future Perspectives

The concept of nanomedicine has evolved significantly in recent decades, leveraging the unique phenomenon known as the enhanced permeability and retention (EPR) effect. This has facilitated major advancements in targeted drug delivery, imaging, and individualized therapy through the integration of nanotechnology principles into medicine. Numerous nanomedicines have been developed and applied for disease treatment, with a particular focus on cancer therapy. Recently, nanomedicine has been utilized in various advanced fields, including diagnosis, vaccines, immunotherapy, gene delivery, and tissue engineering. Multifunctional nanomedicines facilitate concurrent medication delivery, therapeutic monitoring, and imaging, allowing for immediate responses and personalized treatment plans. This review concerns the major advancement of nanomaterials and their potential applications in the biological and medical fields. Along with this, we also mention the various clinical translations of nanomedicine and the major challenges that nanomedicine is currently facing to overcome the clinical translation barrier.

Cold to Hot: Tumor Immunotherapy by Promoting Vascular Normalization Based on PDGFB Nanocomposites

Immunotherapy is a promising cancer therapeutic strategy. However, the "cold" tumor immune microenvironment (TIME), characterized by insufficient immune cell infiltration and immunosuppressive status, limits the efficacy of immunotherapy. Tumor vascular abnormalities due to defective pericyte coverage are gradually recognized as a profound determinant in "cold" TIME establishment by hindering immune cell trafficking. Recently, several vascular normalization strategies by improving pericyte coverage have been reported, whereas have unsatisfactory efficacy and high rates of resistance. Herein, a combinatorial strategy to induce tumor vasculature-targeted pericyte recruitment and zinc ion-mediated immune activation with a platelet-derived growth factor B (PDGFB)-loaded, cyclo (Arg-Gly-Asp-D-Phe-Lys)-modified zeolitic imidazolate framework 8 (PDGFB@ZIF8-RGD) nanoplatform is proposed. PDGFB@ZIF8-RGD effectively induced tumor vascular normalization, which facilitated trafficking and infiltration of immune effector cells, including natural killer (NK) cells, M1-like macrophages and CD8+ T cells, into tumor microenvironment. Simultaneously, vascular normalization promoted the accumulation of zinc ions inside tumors to trigger effector cell immune activation and effector molecule production. The synergy between these two effects endowed PDGFB@ZIF8-RGD with superior capabilities in reprogramming the "cold" TIME to a "hot" TIME, thereby initiating robust antitumor immunity and suppressing tumor growth. This combinatorial strategy for improving immune effector cell infiltration and activation is a promising paradigm for solid tumor immunotherapy.

Nanomedicines for reversing immunosuppressive microenvironment of hepatocellular carcinoma

Although immunotherapeutic strategies such as immune checkpoint inhibitors (ICIs) have gained promising advances, their limited efficacy and significant toxicity remain great challenges for hepatocellular carcinoma (HCC) immunotherapy. The tumor immunosuppressive microenvironment (TIME) with insufficient T-cell infiltration and low immunogenicity accounts for most HCC patients' poor response to ICIs. Worse still, the current immunotherapeutics without precise delivery may elicit enormous autoimmune side effects and systemic toxicity in the clinic. With a better understanding of the TIME in HCC, nanomedicines have emerged as an efficient strategy to achieve remodeling of the TIME and superadditive antitumor effects via targeted delivery of immunotherapeutics or multimodal synergistic therapy. Based on the typical characteristics of the TIME in HCC, this review summarizes the recent advancements in nanomedicine-based strategies for TIME-reversing HCC treatment. Additionally, perspectives on the awaiting challenges and opportunities of nanomedicines in modulating the TIME of HCC are presented. Acquisition of knowledge of nanomedicine-mediated TIME reversal will provide researchers with a better opportunity for clinical translation of HCC immunotherapy.

Polymer-mediated nanoformulations: a promising strategy for cancer immunotherapy

Engineering polymer-based nano-systems have attracted many researchers owing to their unique qualities like shape, size, porosity, mechanical strength, biocompatibility, and biodegradability. Both natural and synthetic polymers can be tuned to get desired surface chemistry and functionalization to improve the efficacy of cancer therapy by promoting targeted delivery to the tumor site. Recent advancements in cancer immunoediting have been able to manage both primary tumor and metastatic lesions via activation of the immune system. The combinations of nano-biotechnology and immunotherapeutic agents have provided positive outcomes by enhancing the host immune response in cancer therapy. The nanoparticles have been functionalized using antibodies, targeted antigens, small molecule ligands, and other novel agents that can interact with biological systems at nanoscale levels. Several polymers, such as polyethylene glycol (PEG), poly(lactic-co-glycolic acid) (PLGA), poly(ε-caprolactone) (PCL), and chitosan, have been approved by the Food and Drug Administration for clinical use in biomedicine. The polymeric nanoformulations such as polymers-antibody/antigen conjugates and polymeric drug conjugates are currently being explored as nanomedicines that can target cancer cells directly or target immune cells to promote anti-cancer immunotherapy. In this review, we focus on scientific developments and advancements on engineered polymeric nano-systems in conjugation with immunotherapeutic agents targeting the tumor microenvironment to improve their efficacy and the safety for better clinical outcomes.

Advancing piezoelectric 2D nanomaterials for applications in drug delivery systems and therapeutic approaches

Precision drug delivery and multimodal synergistic therapy are crucial in treating diverse ailments, such as cancer, tissue damage, and degenerative diseases. Electrodes that emit electric pulses have proven effective in enhancing molecule release and permeability in drug delivery systems. Moreover, the physiological electrical microenvironment plays a vital role in regulating biological functions and triggering action potentials in neural and muscular tissues. Due to their unique noncentrosymmetric structures, many 2D materials exhibit outstanding piezoelectric performance, generating positive and negative charges under mechanical forces. This ability facilitates precise drug targeting and ensures high stimulus responsiveness, thereby controlling cellular destinies. Additionally, the abundant active sites within piezoelectric 2D materials facilitate efficient catalysis through piezochemical coupling, offering multimodal synergistic therapeutic strategies. However, the full potential of piezoelectric 2D nanomaterials in drug delivery system design remains underexplored due to research gaps. In this context, the current applications of piezoelectric 2D materials in disease management are summarized in this review, and the development of drug delivery systems influenced by these materials is forecast.

Advances in the variations and biomedical applications of stimuli-responsive nanodrug delivery systems

Chemotherapy is an important cancer treatment modality, but the clinical utility of chemotherapeutics is limited by their toxic side effects, inadequate distribution and insufficient intracellular concentrations. Nanodrug delivery systems (NDDSs) have shown significant advantages in cancer diagnosis and treatment. Variable NDDSs that respond to endogenous and exogenous triggers have attracted much research interest. Here, we summarized nanomaterials commonly used for tumor therapy, such as peptides, liposomes, and carbon nanotubes, as well as the responses of NDDSs to pH, enzymes, magnetic fields, light, and multiple stimuli. Specifically, well-designed NDDSs can change in size or morphology or rupture when induced by one or more stimuli. The varying responses of NDDSs to stimulation contribute to the molecular design and development of novel NDDSs, providing new ideas for improving drug penetration and accumulation, inhibiting tumor resistance and metastasis, and enhancing immunotherapy.

Nanoparticle-based immunoengineering strategies for enhancing cancer immunotherapy

Cancer immunotherapy is a groundbreaking strategy that has revolutionized the field of oncology compared to other therapeutic strategies, such as surgery, chemotherapy, or radiotherapy. However, cancer complexity, tumor heterogeneity, and immune escape have become the main hurdles to the clinical application of immunotherapy. Moreover, conventional immunotherapies cause many harmful side effects owing to hyperreactivity in patients, long treatment durations and expensive cost. Nanotechnology is considered a transformative approach that enhances the potency of immunotherapy by capitalizing on the superior physicochemical properties of nanocarriers, creating highly targeted tissue delivery systems. These advantageous features include a substantial specific surface area, which enhances the interaction with the immune system. In addition, the capability to finely modify surface chemistry enables the achievement of controlled and sustained release properties. These advances have significantly increased the potential of immunotherapy, making it more powerful than ever before. In this review, we introduce recent nanocarriers for application in cancer immunotherapy based on strategies that target different main immune cells, including T cells, dendritic cells, natural killer cells, and tumor-associated macrophages. We also provide an overview of the role and significance of nanotechnology in cancer immunotherapy.

Nanodelivery Systems as a Novel Strategy to Overcome Treatment Failure of Cancer

Despite the tremendous progress in cancer treatment in recent decades, cancers often become resistant due to multiple mechanisms, such as intrinsic or acquired multidrug resistance, which leads to unsatisfactory treatment effects or accompanying metastasis and recurrence, ultimately to treatment failure. With a deeper understanding of the molecular mechanisms of tumors, researchers have realized that treatment designs targeting tumor resistance mechanisms would be a promising strategy to break the therapeutic deadlock. Nanodelivery systems have excellent physicochemical properties, including highly efficient tissue-specific delivery, substantial specific surface area, and controllable surface chemistry, which endow nanodelivery systems with capabilities such as precise targeting, deep penetration, responsive drug release, multidrug codelivery, and multimodal synergy, which are currently widely used in biomedical researches and bring a new dawn for overcoming cancer resistance. Based on the mechanisms of tumor therapeutic resistance, this review summarizes the research progress of nanodelivery systems for overcoming tumor resistance to improve therapeutic efficacy in recent years and offers prospects and challenges of the application of nanodelivery systems for overcoming cancer resistance.

Advances in tumor immunomodulation based on nanodrug delivery systems

Immunotherapy is a therapeutic approach that employs immunological principles and techniques to enhance and amplify the body's immune response, thereby eradicating tumor cells. Immunotherapy has demonstrated effective antitumor effects on a variety of malignant tumors. However, when applied to humans, many immunotherapy drugs fail to target lesions with precision, leading to an array of adverse immune-related reactions that profoundly limit the clinical application of immunotherapy. Nanodrug delivery systems enable the precise delivery of immunotherapeutic drugs to targeted tissues or specific immune cells, enhancing the immune antitumor effect while reducing the number of adverse reactions. A nanodrug delivery system provides a feasible strategy for activating the antitumor immune response by the following mechanisms: 1) increased targeting and uptake of vaccines by DCs, which enhances the efficacy of the immune response; 2) increased tumor cell immunogenicity; 3) regulation of TAMs and other cells by, for example, regulating the polarization of TAMs and interfering with TAN formation, and ECM remodeling by CAFs; and 4) interference with tumor immune escape signaling pathways, namely, the PD-1/PD-L1, FGL1/LAG-3 and IDO signaling pathways. This paper reviews the progress of nanodrug delivery system research with respect to tumor immunotherapy based on tumor immunomodulation over the last few years, discussing the promising future of these delivery systems under this domain.

Specific interaction based drug loading strategies

Drug carriers have been commonly used for drug control release, enhancing drug efficacy and/or minimizing side-effects. However, it is still difficult to get a high loading efficiency when encapsulating super hydrophilic drugs with a narrow therapeutic index, such as many neurotoxins. Increasing the carrier proportion can improve drug loading to a certain degree, while the burst released drug when the formulation enters the body may cause overdose side-effects. Moreover, high-dose carriers themselves may increase the metabolic burden of the body. Hence, new drug carriers and/or loading strategies are urgently needed to promote the applications of these drugs. This minireview will introduce drug loading strategies based on specific interactions (between drugs and carriers) and will discuss the challenges and perspectives of these strategies. This work is expected to provide alternative inspiration for the delivery of hydrophilic drugs.

Four Ounces Can Move a Thousand Pounds: The Enormous Value of Nanomaterials in Tumor Immunotherapy

The application of nanomaterials in healthcare has emerged as a promising strategy due to their unique structural diversity, surface properties, and compositional diversity. In particular, nanomaterials have found a significant role in improving drug delivery and inhibiting the growth and metastasis of tumor cells. Moreover, recent studies have highlighted their potential in modulating the tumor microenvironment (TME) and enhancing the activity of immune cells to improve tumor therapy efficacy. Various types of nanomaterials are currently utilized as drug carriers, immunosuppressants, immune activators, immunoassay reagents, and more for tumor immunotherapy. Necessarily, nanomaterials used for tumor immunotherapy can be grouped into two categories: organic and inorganic nanomaterials. Though both have shown the ability to achieve the purpose of tumor immunotherapy, their composition and structural properties result in differences in their mechanisms and modes of action. Organic nanomaterials can be further divided into organic polymers, cell membranes, nanoemulsion-modified, and hydrogel forms. At the same time, inorganic nanomaterials can be broadly classified as nonmetallic and metallic nanomaterials. The current work aims to explore the mechanisms of action of these different types of nanomaterials and their prospects for promoting tumor immunotherapy.

Biomaterials Facilitating Dendritic Cell-Mediated Cancer Immunotherapy

Dendritic cell (DC)-based cancer immunotherapy has exhibited remarkable clinical prospects because DCs play a central role in initiating and regulating adaptive immune responses. However, the application of traditional DC-mediated immunotherapy is limited due to insufficient antigen delivery, inadequate antigen presentation, and high levels of immunosuppression. To address these challenges, engineered biomaterials have been exploited to enhance DC-mediated immunotherapeutic effects. In this review, vital principal components that can enhance DC-mediated immunotherapeutic effects are first introduced. The parameters considered in the rational design of biomaterials, including targeting modifications, size, shape, surface, and mechanical properties, which can affect biomaterial optimization of DC functions, are further summarized. Moreover, recent applications of various engineered biomaterials in the field of DC-mediated immunotherapy are reviewed, including those serve as immune component delivery platforms, remodel the tumor microenvironment, and synergistically enhance the effects of other antitumor therapies. Overall, the present review comprehensively and systematically summarizes biomaterials related to the promotion of DC functions; and specifically focuses on the recent advances in biomaterial designs for DC activation to eradicate tumors. The challenges and opportunities of treatment strategies designed to amplify DCs via the application of biomaterials are discussed with the aim of inspiring the clinical translation of future DC-mediated cancer immunotherapies.

Highly Mimetic Ex Vivo Lung-Cancer Spheroid-Based Physiological Model for Clinical Precision Therapeutics

Lung cancer remains a major health problem despite the considerable research into prevention and treatment methods. Through a deeper understanding of tumors, patient-specific ex vivo spheroid models with high specificity can be used to accurately investigate the cause, metastasis, and treatment strategies for lung cancer. Biofabricate lung tumors are presented, consisting of patient-derived tumor spheroids, endothelial cells, and lung decellularized extracellular matrix, which maintain a radial oxygen gradient, as well as biophysicochemical behaviors of the native tumors for precision medicine. It is also demonstrated that the developed lung-cancer spheroid model reproduces patient responses to chemotherapeutics and targeted therapy in a co-clinical trial, with 85% accuracy, 86.7% sensitivity, and 80% specificity. RNA sequencing analysis validates that the gene expression in the spheroids replicates that in the patient's primary tumor. This model can be used as an ex vivo predictive model for personalized cancer therapy and to improve the quality of clinical care.

In Vitro Effects of Waterborne Polyurethane 3D Scaffolds Containing Poly(lactic-co-glycolic acid)s of Different Lactic Acid/Glycolic Acid Ratios on the Inflammatory Response

The physical and chemical properties of tissue engineering scaffolds have considerable effects on the inflammatory response at the implant site in soft tissue repair. The development of inflammation-modulating polymer scaffolds for soft tissue repair is attracting increasing attention. In this study, in order to regulate the inflammatory response at the implant site, a series of waterborne polyurethane (WPU) scaffolds with different properties were synthesized using polyethylene glycol (PEG), polycaprolactone (PCL) and poly (lactic acid)–glycolic acid copolymers (PLGAs) with three lactic acid/glycolic acid (LA/GA) ratios as the soft segments. Then, scaffolds were obtained using freeze-drying. The WPU scaffolds exhibited a porous cellular structure, high porosity, proper mechanical properties for repairing nerve tissue and an adjustable degradation rate. In vitro cellular experiments showed that the degradation solution possessed high biocompatibility. The in vitro inflammatory response of C57BL/6 mouse brain microglia (immortalized) (BV2) cells demonstrated that the LA/GA ratio of the PLGA in WPU scaffolds can regulate the external inflammatory response by altering the secretion of IL-10 and TNF-α. Even the IL-10/TNF-α of PU5050 (3.64) reached 69 times that of the control group (0.053). The results of the PC12 culture on the scaffolds showed that the scaffolds had positive effects on the growth, proliferation and differentiation of nerve cells and could even promote the formation of synapses. Overall, these scaffolds, particularly the PU5050, indeed prevent BV2 cells from differentiating into a pro-inflammatory M1 phenotype, which makes them promising candidates for reducing the inflammatory response and repairing nerve tissue. Furthermore, PU5050 had the best effect on preventing the transformation of BV2 cells into the pro-inflammatory M1 phenotype.