Metal ions and nanometallic materials in antitumor immunity: Function, application, and perspective

Controlled release of manganese and magnesium ions by microsphere-encapsulated hydrogel enhances cancer immunotherapy

Despite the considerable potential of immune checkpoint blockade (ICB) therapy in treating various cancer types, it faces several challenges, of which the constrained objective response rate and relatively short duration of response observed in patients with cancer are the most important. This study introduces an injectable temperature-sensitive hydrogel, Pluronic F-127 (PF-127)@MnCl2/ alginate microspheres (ALG-MS)@MgCl2, that enhances the therapeutic efficacy of programmed cell death-ligand 1 (PD-L1) in cancer cells. The hydrogel material used in this study facilitated the rapid release of a significant amount of manganese ions (Mn2+) and the gradual and sustained release of magnesium ions (Mg2+) within the tumor microenvironment. This staged release profile promotes an immune microenvironment conducive to the cytotoxicity of CD8+ T cells and natural killer cells, thereby enhancing the efficacy of ICB therapy. Furthermore, the PF-127@MnCl2/ALG-MS@MgCl2 composite hydrogel exhibits the ability to convert drug-resistant tumor ("cold tumor") with a low PD-L1 response to a "hot tumor" with a high PD-L1 response. In summary, the PF-127@MnCl2/ALG-MS@MgCl2 hydrogel manipulates the immune microenvironment through the precise discharge of Mg2+ and Mn2+, thus, augmenting the efficacy of ICB therapy.

Transition Metal Oxide Nanomaterials: New Weapons to Boost Anti-Tumor Immunity Cycle

Semiconductor nanomaterials have emerged as a significant factor in the advancement of tumor immunotherapy. This review discusses the potential of transition metal oxide (TMO) nanomaterials in the realm of anti-tumor immune modulation. These binary inorganic semiconductor compounds possess high electron mobility, extended ductility, and strong stability. Apart from being primary thermistor materials, they also serve as potent agents in enhancing the anti-tumor immunity cycle. The diverse metal oxidation states of TMOs result in a range of electronic properties, from metallicity to wide-bandgap insulating behavior. Notably, titanium oxide, manganese oxide, iron oxide, zinc oxide, and copper oxide have garnered interest due to their presence in tumor tissues and potential therapeutic implications. These nanoparticles (NPs) kickstart the tumor immunity cycle by inducing immunogenic cell death (ICD), prompting the release of ICD and tumor-associated antigens (TAAs) and working in conjunction with various therapies to trigger dendritic cell (DC) maturation, T cell response, and infiltration. Furthermore, they can alter the tumor microenvironment (TME) by reprogramming immunosuppressive tumor-associated macrophages into an inflammatory state, thereby impeding tumor growth. This review aims to bring attention to the research community regarding the diversity and significance of TMOs in the tumor immunity cycle, while also underscoring the potential and challenges associated with using TMOs in tumor immunotherapy.

Osteogenic Induction and Anti-Inflammatory Effects of Calcium-Chlorogenic Acid Nanoparticles Remodel the Osteoimmunology Microenvironment for Accelerating Bone Repair

Successful bone regeneration requires close cooperation between bone marrow mesenchymal stem cells (BMSCs) and macrophages, but the low osteogenic differentiation efficiency of stem cells and the excessive inflammatory response of immune cells hinder the development of bone repair. It is necessary to develop a strategy that simultaneously regulates the osteogenic differentiation of BMSCs and the anti-inflammatory polarization of macrophages for accelerating the bone regeneration. Herein, calcium-chlorogenic acid nanoparticles (Ca-CGA NPs) are synthesized by combining the small molecules of chlorogenic acid (CGA) with Ca2+. Ca-CGA NPs internalized by cells can be dissolved to release free CGA and Ca2+ under low pH conditions in lysosomes. In vitro results demonstrate that Ca-CGA NPs can not only enhance the osteogenic differentiation of BMSCs but also promote the phenotype transformation of macrophages from M1 to M2. Furthermore, in vivo experiments confirm that Ca-CGA NPs treatment facilitates the recovery of rat skull defect model through both osteoinduction and immunomodulation. This study develops a new Ca-CGA NPs-based strategy to induce the differentiation of BMSCs into osteoblasts and the polarization of macrophages into M2 phenotype, which is promising for accelerating bone repair.

Dendritic nanoparticles for immune modulation: a potential next-generation nanocarrier for cancer immunotherapy

Immune activation, whether occurring from direct immune checkpoint blockade or indirectly as a result of chemotherapy, is an approach that has drastically impacted the way we treat cancer. Utilizing patients' own immune systems for anti-tumor efficacy has been translated to robust immunotherapies; however, clinically significant successes have been achieved in only a subset of patient populations. Dendrimers and dendritic polymers have recently emerged as a potential nanocarrier platform that significantly improves the therapeutic efficacy of current and next-generation cancer immunotherapies. In this paper, we highlight the recent progress in developing dendritic polymer-based therapeutics with immune-modulating properties. Specifically, dendrimers, dendrimer hybrids, and dendronized copolymers have demonstrated promising results and are currently in pre-clinical development. Despite their early stage of development, these nanocarriers hold immense potential to make profound impact on cancer immunotherapy and combination therapy. This overview provides insights into the potential impact of dendrimers and dendron-based polymers, offering a preview of their potential utilities for various aspects of cancer treatment.

Immune regulation enhances osteogenesis and angiogenesis using an injectable thiolated hyaluronic acid hydrogel with lithium-doped nano-hydroxyapatite (Li-nHA) delivery for osteonecrosis

Osteonecrosis is a devastating orthopedic disease in clinic that generally occurs in the femoral head associating with corticosteroid use up to 49 % in patients. In particular, glucocorticoids induced osteonecrosis of the femoral head is closely related to the local immune response that characterized by abnormal macrophage activation and inflammatory cell infiltration at the necrotic site, forming a pro-inflammatory microenvironment dominated by M1 macrophages, and thus leads to failure of bone repair and regeneration. Here, we report a bone regeneration strategy that constructs an immune regulatory biomaterial platform using an injectable thiolated hyaluronic acid hydrogel with lithium-doped nano-hydroxyapatite (Li-nHA@Gel) delivery for osteonecrosis treatment. Li-nHA@Gel achieved a sustain and longterm release of Li ions, which might enhance M2 macrophage polarization through the activation of the JAK1/STAT6/STAT3 signaling pathway, and the following induced pro-repair immune microenvironment mediated the enhancement of the osteogenic and angiogenic differentiation. Moreover, both in vitro and in vivo studies indicated that Li-nHA@Gel enhanced M2 macrophage polarization, osteogenesis, and angiogenesis, and thus promoted the bone and blood vessel formation. Taken together, this novel bone immunomodulatory biomaterial platform that promotes bone regeneration by enhancing M2 macrophage polarization, osteogenesis, and angiogenesis could be a promising strategy for osteonecrosis treatment.

Nanomaterial-mediated modulation of the cGAS-STING signaling pathway for enhanced cancer immunotherapy

Despite the current promise of immunotherapy, many cancer patients still suffer from challenges such as poor immune response rates, resulting in unsatisfactory clinical efficacy of existing therapies. There is an urgent need to combine emerging biomedical discoveries and innovations in traditional therapies. Modulation of the cGAS-STING signalling pathway represents an important innate immunotherapy pathway that serves as a crucial DNA sensing mechanism in innate immunity and viral defense. It has attracted increasing attention as an emerging target for cancer therapy. The recent advancements in nanotechnology have led to the significant utilization of nanomaterials in cancer immunotherapy, owing to their exceptional physicochemical properties such as large specific surface area and efficient permeability. Given the rapid development of cancer immunotherapy driven by the cGAS-STING activation, this study reviews the latest research progress in employing nanomaterials to modulate this signaling pathway. Based on the introduction of the main activation mechanisms of cGAS-STING pathway, this review focuses on nanomaterials that mediate the agonists involved and effectively activate this signaling pathway. In addition, combination nanotherapeutics based on the activation of the cGAS-STING signaling pathway are also discussed, including emerging strategies combining nanoformulated agonists with chemotherapy, radiotherapy as well as other immunomodulation in tumor targeting therapy. STATEMENT OF SIGNIFICANCE: Given the rapid development of cancer immunotherapy driven by the cGAS / STING activation, this study reviews the latest research advances in the use of nanomaterials to modulate this signaling pathway. Based on the introduction of key cGAS-STING components and their activation mechanisms, this review focuses on nanomaterials that can mediate the corresponding agonists and effectively activate this signaling pathway. In addition, combination nanotherapies based on the activation of the cGAS-STING signaling pathway are also discussed, including emerging strategies combining nanoformulated agonists with chemotherapy, radiotherapy as well as immunomodulation in cancer therapy,.

Non-bone-derived exosomes: a new perspective on regulators of bone homeostasis

Accumulating evidence indicates that exosomes help to regulate bone homeostasis. The roles of bone-derived exosomes have been well-described; however, recent studies have shown that some non-bone-derived exosomes have better bone targeting ability than bone-derived exosomes and that their performance as a drug delivery vehicle for regulating bone homeostasis may be better than that of bone-derived exosomes, and the sources of non-bone-derived exosomes are more extensive and can thus be better for clinical needs. Here, we sort non-bone-derived exosomes and describe their composition and biogenesis. Their roles and specific mechanisms in bone homeostasis and bone-related diseases are also discussed. Furthermore, we reveal obstacles to current research and future challenges in the practical application of exosomes, and we provide potential strategies for more effective application of exosomes for the regulation of bone homeostasis and the treatment of bone-related diseases. Video Abstract.

Fe3+ mediated shikonin and PPA coloaded liposomes induce robust immunogenic cell death by integrating ROS enhancement and GSH depletion

Reactive oxygen species (ROS) can not only induce cellular oxidative stress, but also trigger antitumor immune response. However, single ROS generated therapy is usually not enough to induce efficient antitumor immune response. Furthermore, the adaptive antioxidant mechanisms coupled with overexpressed ROS can also decrease the antitumor capacity of ROS therapy. To circumvent this problem, we designed a synergistic strategy for inducing robust ROS based ICD effect by constructing a coloaded liposomes (PPA, Pyropheophorbide-alpha and SHK, shikonin) with Fe3+ gradient to simultaneously enhance ROS mediated oxidative stress and glutathione depletion. Interestingly, the coloaded liposome possesses an acid/GSH dual triggered release profile. More importantly, with the help of depleting GSH, LipoPS (coloaded liposome of SHK and PPA) can excite robust ROS and demonstrate synergistic antitumor efficacy with amplified ICD effect. Summarized, the established coloaded liposome LipoPS exhibits good therapeutic security and synergistic antitumor effect with strong antitumor immune activation, providing potential for further development.

Evolving approaches in glioma treatment: harnessing the potential of copper metabolism modulation

The key properties and high versatility of metal nanoparticles have shed new perspectives on cancer therapy, with copper nanoparticles gaining great interest because of the ability to couple the intrinsic properties of metal nanoparticles with the biological activities of copper ions in cancer cells. Copper, indeed, is a cofactor involved in different metabolic pathways of many physiological and pathological processes. Literature data report on the use of copper in preclinical protocols for cancer treatment based on chemo-, photothermal-, or copper chelating-therapies. Copper nanoparticles exhibit anticancer activity via multiple routes, mainly involving the targeting of mitochondria, the modulation of oxidative stress, the induction of apoptosis and autophagy, and the modulation of immune response. Moreover, compared to other metal nanoparticles (e.g. gold, silver, palladium, and platinum), copper nanoparticles are rapidly cleared from organs with low systemic toxicity and benefit from the copper's low cost and wide availability. Within this review, we aim to explore the impact of copper in cancer research, focusing on glioma, the most common primary brain tumour. Glioma accounts for about 80% of all malignant brain tumours and shows a poor prognosis with the five-year survival rate being less than 5%. After introducing the glioma pathogenesis and the limitation of current therapeutic strategies, we will discuss the potential impact of copper therapy and present the key results of the most relevant literature to establish a reliable foundation for future development of copper-based approaches.

pH-Responsive Zinc Ion Regulating Immunomodulatory Nanoparticles for Effective Cancer Immunotherapy

Herein, we introduce a novel approach involving the utilization of a human serum albumin-coated zeolite imidazolate framework-8 containing a photosensitizer (HPZ) that exhibits targeted recognition of the tumor microenvironment, enabling the rapid elevation of zinc ion concentrations while facilitating the controlled release of an encapsulated photosensitizer (PS). At a physiological pH of 7.4, HPZ demonstrates a size of approximately 170 nm, significantly decreasing to less than 10 nm under pH 6.5 acidic conditions. Acid-induced decomposition of HPZ triggers a rapid increase in zinc ion concentration, eliciting potent cytotoxic effects against colorectal, breast, and pancreatic cancers. Additionally, upon laser irradiation, the encapsulated PS within HPZ initiates the generation of reactive oxygen species, synergistically augmenting the cytotoxicity induced by zinc ions. Intravenous administration of HPZ in a CT26 tumor-bearing mouse model resulted in a notable expansion of CD3+CD4+ helper T cells and CD3+CD8+ cytotoxic T cells, accompanied by a reduction in the CD4+CD25+Foxp3+ regulatory T-cell population. These changes led to significant inhibition of tumor growth, highlighting the efficacy of HPZ in this experimental model. Importantly, HPZ exhibits favorable safety characteristics, displaying no toxicity toward vital organs and inducing no weight loss. Thus, HPZ holds immense promise as a standalone treatment or in combination with diverse anticancer immunotherapies, underscoring its potential in the field of anticancer immunotherapy.

Copper-induced injectable hydrogel with nitric oxide for enhanced immunotherapy by amplifying immunogenic cell death and regulating cancer associated fibroblasts

BACKGROUND

Immunogenic cell death (ICD) induced by different cancer treatments has been widely evaluated to recruit immune cells and trigger the specific antitumor immunity. However, cancer associated fibroblasts (CAFs) can hinder the invasion of immune cells and polarize the recruited monocytes to M2-type macrophages, which greatly restrict the efficacy of immunotherapy (IT).

METHODS

In this study, an injectable hydrogel induced by copper (Cu) has been designed to contain antibody of PD-L1 and nitric oxide (NO) donor. The therapeutic efficacy of hydrogel was studied in 4T1 cells and CAFs in vitro and 4T1 tumor-bearing mice in vivo. The immune effects on cytotoxic T lymphocytes, dendritic cells (DCs) and macrophages were analyzed by flow cytometry. Enzyme-linked immunosorbent assay, immunofluorescence and transcriptome analyses were also performed to evaluate the underlying mechanism.

RESULTS

Due to the absorbance of Cu with the near-infrared laser irradiation, the injectable hydrogel exhibits persistent photothermal effect to kill cancer cells. In addition, the Cu of hydrogel shows the Fenton-like reaction to produce reactive oxygen species as chemodynamic therapy, thereby enhancing cancer treatment and amplifying ICD. More interestingly, we have found that the released NO can significantly increase depletion of CAFs and reduce the proportion of M2-type macrophages in vitro. Furthermore, due to the amplify of ICD, injectable hydrogel can effectively increase the infiltration of immune cells and reverse the immunosuppressive tumor microenvironment (TME) by regulating CAFs to enhance the therapeutic efficacy of anti-PD-L1 in vivo.

CONCLUSIONS

The ion induced self-assembled hydrogel with NO could enhance immunotherapy via amplifying ICD and regulating CAFs. It provides a novel strategy to provoke a robust antitumor immune response for clinical cancer immunotherapy.

Prospects for the Use of Metal-Based Nanoparticles as Adjuvants for Local Cancer Immunotherapy

Immunotherapy is among the most effective approaches for treating cancer. One of the key aspects for successful immunotherapy is to achieve a strong and stable antitumor immune response. Modern immune checkpoint therapy demonstrates that cancer can be defeated. However, it also points out the weaknesses of immunotherapy, as not all tumors respond to therapy and the co-administration of different immunomodulators may be severely limited due to their systemic toxicity. Nevertheless, there is an established way through which to increase the immunogenicity of immunotherapy-by the use of adjuvants. These enhance the immune response without inducing such severe adverse effects. One of the most well-known and studied adjuvant strategies to improve immunotherapy efficacy is the use of metal-based compounds, in more modern implementation-metal-based nanoparticles (MNPs), which are exogenous agents that act as danger signals. Adding innate immune activation to the main action of an immunomodulator makes it capable of eliciting a robust anti-cancer immune response. The use of an adjuvant has the peculiarity of a local administration of the drug, which positively affects its safety. In this review, we will consider the use of MNPs as low-toxicity adjuvants for cancer immunotherapy, which could provide an abscopal effect when administered locally.

Combining Copper and Zinc into a Biosensor for Anti-Chemoresistance and Achieving Osteosarcoma Therapeutic Efficacy

Due to its built-up chemoresistance after prolonged usage, the demand for replacing platinum in metal-based drugs (MBD) is rising. The first MBD approved by the FDA for cancer therapy was cisplatin in 1978. Even after nearly four and a half decades of trials, there has been no significant improvement in osteosarcoma (OS) therapy. In fact, many MBD have been developed, but the chemoresistance problem raised by platinum remains unresolved. This motivates us to elucidate the possibilities of the copper and zinc (CuZn) combination to replace platinum in MBD. Thus, the anti-chemoresistance properties of CuZn and their physiological functions for OS therapy are highlighted. Herein, we summarise their chelators, main organic solvents, and ligand functions in their structures that are involved in anti-chemoresistance properties. Through this review, it is rational to discuss their ligands' roles as biosensors in drug delivery systems. Hereafter, an in-depth understanding of their redox and photoactive function relationships is provided. The disadvantage is that the other functions of biosensors cannot be elaborated on here. As a result, this review is being developed, which is expected to intensify OS drugs with higher cure rates. Nonetheless, this advancement intends to solve the major chemoresistance obstacle towards clinical efficacy.