Amplified Cancer Immunotherapy of a Surface-Engineered Antigenic Microparticle Vaccine by Synergistically Modulating Tumor Microenvironment

Hyperthermia/glutathione-triggered ferritin nanoparticles amplify the ferroptosis for synergistic tumor therapy

Breast cancer is the most diagnosed malignancy in women globally, and drug resistance is among the major obstacles to effective breast cancer treatment. Emerging evidence indicates that photothermal therapy and ferroptosis are both promising therapeutic techniques for the treatment of drug-resistant breast tumors. In this study, we proposed a thermal/ferroptosis/magnetic resonance imaging (MRI) triple functional nanoparticle (I@P-ss-FRT) in which ferritin, an iron storage material with excellent cellular uptake capacity, was attached via disulfide bonds onto polydopamine coated iron oxide nanoparticle (I@P) as photothermal transduction agent and MRI probe. I@P-ss-FRT converted the near-infrared light (NIR) into localized heat which accelerated the release of ferrous ions from ferritin accomplished by glutathione reduction and subsequently induced ferroptosis. The drug-resistant cancer cell lines exhibited a more significant uptake of I@P-ss-FRT and sensitivity to PTT/ferroptosis compared with normal cancer cell lines. In vivo, I@P-ss-FRT plus NIR displayed the best tumor-killing potential with inhibitory rate of 83.46 %, along with a decline in GSH/GPX-4 content and an increase in lipid peroxides generation at tumor sites. Therefore, I@P-ss-FRT can be applied to combat drug-resistant breast cancer.

Bioinspired ginsenoside Rg3 PLGA nanoparticles coated with tumor-derived microvesicles to improve chemotherapy efficacy and alleviate toxicity

Breast cancer, a pervasive malignancy affecting women, demands a diverse treatment approach including chemotherapy, radiotherapy, and surgical interventions. However, the effectiveness of doxorubicin (DOX), a cornerstone in breast cancer therapy, is limited when used as a monotherapy, and concerns about cardiotoxicity persist. Ginsenoside Rg3, a classic compound of traditional Chinese medicine found in Panax ginseng C. A. Mey., possesses diverse pharmacological properties, including cardiovascular protection, immune modulation, and anticancer effects. Ginsenoside Rg3 is considered a promising candidate for enhancing cancer treatment when combined with chemotherapy agents. Nevertheless, the intrinsic challenges of Rg3, such as its poor water solubility and low oral bioavailability, necessitate innovative solutions. Herein, we developed Rg3-PLGA@TMVs by encapsulating Rg3 within PLGA nanoparticles (Rg3-PLGA) and coating them with membranes derived from tumor cell-derived microvesicles (TMVs). Rg3-PLGA@TMVs displayed an array of favorable advantages, including controlled release, prolonged storage stability, high drug loading efficiency and a remarkable ability to activate dendritic cells in vitro. This activation is evident through the augmentation of CD86+CD80+ dendritic cells, along with a reduction in phagocytic activity and acid phosphatase levels. When combined with DOX, the synergistic effect of Rg3-PLGA@TMVs significantly inhibits 4T1 tumor growth and fosters the development of antitumor immunity in tumor-bearing mice. Most notably, this delivery system effectively mitigates the toxic side effects of DOX, particularly those affecting the heart. Overall, Rg3-PLGA@TMVs provide a novel strategy to enhance the efficacy of DOX while simultaneously mitigating its associated toxicities and demonstrate promising potential for the combined chemo-immunotherapy of breast cancer.

Emerging nanoparticle platforms for CpG oligonucleotide delivery

Unmethylated cytosine-phosphate-guanine (CpG) oligodeoxynucleotides (ODNs), which were therapeutic DNA with high immunostimulatory activity, have been applied in widespread applications from basic research to clinics as therapeutic agents for cancer immunotherapy, viral infection, allergic diseases and asthma since their discovery in 1995. The major factors to consider for clinical translation using CpG motifs are the protection of CpG ODNs from DNase degradation and the delivery of CpG ODNs to the Toll-like receptor-9 expressed human B-cells and plasmacytoid dendritic cells. Therefore, great efforts have been devoted to the advances of efficient delivery systems for CpG ODNs. In this review, we outline new horizons and recent developments in this field, providing a comprehensive summary of the nanoparticle-based CpG delivery systems developed to improve the efficacy of CpG-mediated immune responses, including DNA nanostructures, inorganic nanoparticles, polymer nanoparticles, metal-organic-frameworks, lipid-based nanosystems, proteins and peptides, as well as exosomes and cell membrane nanoparticles. Moreover, future challenges in the establishment of CpG delivery systems for immunotherapeutic applications are discussed. We expect that the continuously growing interest in the development of CpG-based immunotherapy will certainly fuel the excitement and stimulation in medicine research.

The Role of Extracellular Vesicles in the Treatment of Prostate Cancer

Prostate cancer (PCa) has become a public health concern in elderly men due to an ever-increasing number of estimated cases. Unfortunately, the available treatments are unsatisfactory because of a lack of a durable response, especially in advanced disease states. Extracellular vesicles (EVs) are lipid-bilayer encircled nanoscale vesicles that carry numerous biomolecules (e.g., nucleic acids, proteins, and lipids), mediating the transfer of information. The past decade has witnessed a wide range of EV applications in both diagnostics and therapeutics. First, EV-based non-invasive liquid biopsies provide biomarkers in various clinical scenarios to guide treatment; EVs can facilitate the grading and staging of patients for appropriate treatment selection. Second, EVs play a pivotal role in pathophysiological processes via intercellular communication. Targeting key molecules involved in EV-mediated tumor progression (e.g., proliferation, angiogenesis, metastasis, immune escape, and drug resistance) is a potential approach for curbing PCa. Third, EVs are promising drug carriers. Naïve EVs from various sources and engineered EV-based drug delivery systems have paved the way for the development of new treatment modalities. This review discusses the recent advancements in the application of EV therapies and highlights EV-based functional materials as novel interventions for PCa.

Tumor-derived microvesicles for cancer therapy

Extracellular vesicles (EVs) are vesicles with lipid bilayer structures shed from the plasma membrane of cells. Microvesicles (MVs) are a subset of EVs containing proteins, lipids, nucleic acids, and other metabolites. MVs can be produced under specific cell stimulation conditions and isolated by modern separation technology. Due to their tumor homing and large volume, tumor cell-derived microvesicles (TMVs) have attracted interest recently and become excellent delivery carriers for therapeutic vaccines, imaging agents or antitumor drugs. However, preparing sufficient and high-purity TMVs and conducting clinical transformation has become a challenge in this field. In this review, the recent research achievements in the generation, isolation, characterization, modification, and application of TMVs in cancer therapy are reviewed, and the challenges facing therapeutic applications are also highlighted.

In Situ Vaccination with An Injectable Nucleic Acid Hydrogel for Synergistic Cancer Immunotherapy

Recently, therapeutic cancer vaccines have emerged as promising candidates for cancer immunotherapy. Nevertheless, their efficacies are frequently impeded by challenges including inadequate antigen encapsulation, insufficient immune activation, and immunosuppressive tumor microenvironment. Herein, we report a three-in-one hydrogel assembled by nucleic acids (NAs) that can serve as a vaccine to in situ trigger strong immune response against cancer. Through site-specifically grafting the chemodrug, 7-ethyl-10-hydroxycamptothecin (also known as SN38), onto three component phosphorothioate (PS) DNA strands, a Y-shaped motif (Y-motif) with sticky ends is self-assembled, at one terminus of which an unmethylated cytosine-phosphate-guanine (CpG) segment is introduced as an immune agonist. Thereafter, programmed cell death ligand-1 (PD-L1) siRNA that performs as immune checkpoint inhibitor is designed as a crosslinker to assemble with the CpG- and SN38-containing Y-motif, resulting in the formation of final NA hydrogel vaccine. With three functional agents inside, the hydrogel can remarkably induce the immunogenic cell death to enhance the antigen presentation, promoting the dendritic cell maturation and effector T lymphocyte infiltration, as well as relieving the immunosuppressive tumor environment. When inoculated twice at tumor sites, the vaccine demonstrates a substantial antitumor effect in melanoma mouse model, proving its potential as a general platform for synergistic cancer immunotherapy.

Multifunctional nanocomposites modulating the tumor microenvironment for enhanced cancer immunotherapy

Cancer immunotherapy has gained momentum for treating malignant tumors over the past decade. Checkpoint blockade and chimeric antigen receptor cell therapy (CAR-T) have shown considerable potency against liquid and solid cancers. However, the tumor microenvironment (TME) is highly immunosuppressive and hampers the effect of currently available cancer immunotherapies on overall treatment outcomes. Advancements in the design and engineering of nanomaterials have opened new avenues to modulate the TME. Progress in the current nanocomposite technology can overcome immunosuppression and trigger robust immunotherapeutic responses by integrating synergistic functions of different molecules. We will review recent advancements in nanomedical applications and discuss specifically designed nanocomposites modulating the TME for cancer immunotherapy. In addition, we provide information on the current landscape of clinical-stage nanocomposites for cancer immunotherapy.

Engineered tumor microvesicles modified by SP94 peptide for arsenic trioxide targeting drug delivery in liver cancer therapy

Liver cancer is among the leading cause of cancer related death worldwide. There is growing interest in using traditional Chinese medicines such as arsenic trioxide (ATO) to treat liver cancer. ATO have attracted attention due to its wide range of anti-cancer activities. However, the current ATO formulations are associated with drawbacks such as short half-life, lack of targeting ability towards solid tumors and apparent toxic side effects. Tumor microvesicles (TMVs) has shown encouraging results for the delivery of drugs to solid tumor. In this work, we designed ATO loaded TMVs further modified by SP94 peptide as liver cancer specific ligand (ATO@SP94-TMVs). This drug delivery system utilized SP94 peptide that selectively targets liver cancer cells while TMVs increase the accumulation of ATO at tumor site and activate immune response owing to the associated antigens. ATO@SP94-TMVs exhibited high encapsulation efficiency and tumor microenvironment triggered enhanced release of ATO in vitro. Cytotoxicity and uptake studies revealed remarkable inhibition and specific targeting of H22 cells. In addition, excellent immune response was detected in vitro, enhancing anti-tumor efficacy. Furthermore, a tumor inhibition rate of about 53.23 % was observed in H22 bearing tumor model. Overall, these results confirm that ATO@SP94-TMVs can be a promising nano drug delivery system for the future liver cancer therapy and improve its clinical applications.

Biomimetic Systems Involving Macrophages and Their Potential for Targeted Drug Delivery

The concept of targeted drug delivery can be described in terms of the drug systems' ability to mimic the biological objects' property to localize to target cells or tissues. For example, drug delivery systems based on red blood cells or mimicking some of their useful features, such as long circulation in stealth mode, have been known for decades. On the contrary, therapeutic strategies based on macrophages have gained very limited attention until recently. Here, we review two biomimetic strategies associated with macrophages that can be used to develop new therapeutic modalities: first, the mimicry of certain types of macrophages (i.e., the use of macrophages, including tumor-associated or macrophage-derived particles as a carrier for the targeted delivery of therapeutic agents); second, the mimicry of ligands, naturally absorbed by macrophages (i.e., the use of therapeutic agents specifically targeted at macrophages). We discuss the potential applications of biomimetic systems involving macrophages for new advancements in the treatment of infections, inflammatory diseases, and cancer.

Orchestrating antigen delivery and presentation efficiency in lymph node by nanoparticle shape for immune response

Activating humoral and cellular immunity in lymph nodes (LNs) of nanoparticle-based vaccines is critical to controlling tumors. However, how the physical properties of nanovaccine carriers orchestrate antigen capture, lymphatic delivery, antigen presentation and immune response in LNs is largely unclear. Here, we manufactured gold nanoparticles (AuNPs) with the same size but different shapes (cages, rods, and stars), and loaded tumor antigen as nanovaccines to explore their disparate characters on above four areas. Results revealed that star-shaped AuNPs captured and retained more repetitive antigen epitopes. On lymphatic delivery, both rods and star-shaped nanovaccines mainly drain into the LN follicles region while cage-shaped showed stronger paracortex retention. A surprising finding is that the star-shaped nanovaccines elicited potent humoral immunity, which is mediated by CD4+ T helper cell and follicle B cell cooperation significantly preventing tumor growth in the prophylactic study. Interestingly, cage-shaped nanovaccines preferentially presented peptide-MHC I complexes to evoke robust CD8+ T cell immunity and showed the strongest therapeutic efficacy when combined with the PD-1 checkpoint inhibitor in established tumor study. These results highlight the importance of nanoparticle shape on antigen delivery and presentation for immune response in LNs, and our findings support the notion that different design strategies are required for prophylactic and therapeutic vaccines.

Research progress of nanovaccine in anti-tumor immunotherapy

Tumor vaccines aim to activate dormant or unresponsive tumor-specific T lymphocytes by using tumor-specific or tumor-associated antigens, thus enhancing the body's natural defense against cancer. However, the effectiveness of tumor vaccines is limited by the presence of tumor heterogeneity, low immunogenicity, and immune evasion mechanisms. Fortunately, multifunctional nanoparticles offer a unique chance to address these issues. With the advantages of their small size, high stability, efficient drug delivery, and controlled surface chemistry, nanomaterials can precisely target tumor sites, improve the delivery of tumor antigens and immune adjuvants, reshape the immunosuppressive tumor microenvironment, and enhance the body's anti-tumor immune response, resulting in improved efficacy and reduced side effects. Nanovaccine, a type of vaccine that uses nanotechnology to deliver antigens and adjuvants to immune cells, has emerged as a promising strategy for cancer immunotherapy due to its ability to stimulate immune responses and induce tumor-specific immunity. In this review, we discussed the compositions and types of nanovaccine, and the mechanisms behind their anti-tumor effects based on the latest research. We hope that this will provide a more scientific basis for designing tumor vaccines and enhancing the effectiveness of tumor immunotherapy.

Adjuvant physiochemistry and advanced nanotechnology for vaccine development

Vaccines comprising innovative adjuvants are rapidly reaching advanced translational stages, such as the authorized nanotechnology adjuvants in mRNA vaccines against COVID-19 worldwide, offering new strategies to effectively combat diseases threatening human health. Adjuvants are vital ingredients in vaccines, which can augment the degree, extensiveness, and longevity of antigen specific immune response. The advances in the modulation of physicochemical properties of nanoplatforms elevate the capability of adjuvants in initiating the innate immune system and adaptive immunity, offering immense potential for developing vaccines against hard-to-target infectious diseases and cancer. In this review, we provide an essential introduction of the basic principles of prophylactic and therapeutic vaccination, key roles of adjuvants in augmenting and shaping immunity to achieve desired outcomes and effectiveness, and the physiochemical properties and action mechanisms of clinically approved adjuvants for humans. We particularly focus on the preclinical and clinical progress of highly immunogenic emerging nanotechnology adjuvants formulated in vaccines for cancer treatment or infectious disease prevention. We deliberate on how the immune system can sense and respond to the physicochemical cues (e.g., chirality, deformability, solubility, topology, and chemical structures) of nanotechnology adjuvants incorporated in the vaccines. Finally, we propose possible strategies to accelerate the clinical implementation of nanotechnology adjuvanted vaccines, such as in-depth elucidation of nano-immuno interactions, antigen identification and optimization by the deployment of high-dimensional multiomics analysis approaches, encouraging close collaborations among scientists from different scientific disciplines and aggressive exploration of novel nanotechnologies.

Tumor-Associated Macrophages Regulating a Polymer Nanoplatform for Synergistic Treatment of Breast Tumors

Tumor-associated macrophages (TAMs) play a critical role in tumor progression and metastasis. Modulation of TAM polarization is one of the most effective strategies to change the immunosuppressive tumor microenvironment (TME). In this study, organic polymer nanoparticles (CPHT) were prepared using hyaluronic acid (HA)-conjugated disulfide-bonded polyethylene imide (PEIS) as a carrier through a self-assembly strategy. These nanoparticles were modified by transferrin (Tf) and loaded with chlorin e6 (Ce6). The results showed that CPHT had good dispersion with a particle size of about 30 nm. CPHT gradually disintegrated under the exposure with a high concentration of glutathione (GSH) in tumor cells, proving the possibility for the controlled release of Ce6 and photodynamic therapy. An in vitro test showed that the uptake of CPHT in tumor cells was mediated by both HA and Tf, indicating the active tumor-targeting capacity of CPHT. CPHT significantly downregulated the ratio of CD206/CD86 and triggered the upregulation of immune factors such as TNF-α and iNOS, suggesting the repolarization of TAMs. We also found that CPHT effectively induced ferroptosis in tumor cells through lipid peroxide accumulation, GSH depletion, and downregulation of lipid peroxidase (GPX4) expression. Animal experiments confirmed that CPHT not only effectively inhibited the growth of tumors in situ but also significantly decelerated the growth of the distal tumor. Elevated levels of CD86 and IFN-γ and decreased expression of CD206 were observed at the tumor sites post CPHT treatment. These results confirmed the value of CPHT as a multifunctional nanoplatform that can tune the TME and provide new hope for tumor treatment.

Immune checkpoint inhibition mediated with liposomal nanomedicine for cancer therapy

Immune checkpoint blockade (ICB) therapy for cancer has achieved great success both in clinical results and on the market. At the same time, success drives more attention from scientists to improve it. However, only a small portion of patients are responsive to this therapy, and it comes with a unique spectrum of side effects termed immune-related adverse events (irAEs). The use of nanotechnology could improve ICBs' delivery to the tumor, assist them in penetrating deeper into tumor tissues and alleviate their irAEs. Liposomal nanomedicine has been investigated and used for decades, and is well-recognized as the most successful nano-drug delivery system. The successful combination of ICB with liposomal nanomedicine could help improve the efficacy of ICB therapy. In this review, we highlighted recent studies using liposomal nanomedicine (including new emerging exosomes and their inspired nano-vesicles) in associating ICB therapy.

Self-delivery photodynamic-hypoxia alleviating nanomedicine synergizes with anti-PD-L1 for cancer immunotherapy

The low level of T-lymphocyte infiltration in tumor is a key issue in cancer immunotherapy. Stimulating anti-tumor immune responses and improving the tumor microenvironment are essential for enhancing anti-PD-L1 immunotherapy. Herein, atovaquone (ATO), protoporphyrin IX (PpIX), and stabilizer (ATO/PpIX NPs) were constructed to self-assemble with hydrophobic interaction and passively targeted to tumor for the first time. The studies have indicated that PpIX-mediated photodynamic induction of immunogenic cell death combined with relieving tumor hypoxia by ATO, leading to maturation of dendritic cells, polarization of M2-type tumor-associated macrophages (TAMs) towards M1-type TAMs, infiltration of cytotoxic T lymphocytes, reduction of regulatory T cells, release of pro-inflammatory cytokines, resulting in an effective anti-tumor immune response synergized with anti-PD-L1 against primary tumor and pulmonary metastasis. Taken together, the combined nanoplatform may be a promising strategy to enhance cancer immunotherapy.

"Trojan horse" nanoparticle-delivered cancer cell membrane vaccines to enhance cancer immunotherapy by overcoming immune-escape

Cancer cell membranes (CCMs) have emerged as advanced cancer treatment vaccines to boost the immune response against cancer and have shown great potential in cancer immunotherapy. However, the CCM vaccine confronts the challenges of a weak and short immune response, ascribed to the immune escape and low accumulation of the CCM in antigen presentation cells (APCs). To overcome these shortcomings, we devised a "Trojan horse" CCM nano-vaccine delivered by layered double hydroxide (LDH) nanoparticles with mannose targeting and bovine serum albumin (BSA) coating to overcome the immune escape challenge, efficiently boosting the immune response to cancer cells. This "Trojan horse" CCM nano-vaccine, named LGCMB, is constructed by assembling the CCM antigen on CpG-LDH (LG), followed by mannose-BSA coating for the APC target and BSA coating to mask immune-escape protein on the CCM. The in vitro cellular uptake and maturation data have clearly shown that the BSA coating strategy with mannose as a "Trojan horse" efficiently targeted APCs (macrophages and DCs) and effectively inhibited the immune escape of the CCM, competently stimulating the APC maturation. Moreover, LGCMB can migrate to the draining lymph nodes (LNs) and trigger tumor-specific CD8⁺ T cell responses in vivo. As expected, the LGCMB nano-vaccine significantly suppressed tumor growth in vivo, showing great potential as a precision cancer vaccine.

Apoptotic tumor cell-derived microparticles loading Napabucasin inhibit CSCs and synergistic immune therapy

BACKGROUND

Cancer stem cells (CSCs) are crucial for the growth, metastasis, drug resistance, recurrence, and spread of tumors. Napabucasin (NAP) could effectively inhibit CSC, but its mechanism has not been fully explained. Additionally, NAP also has the drawbacks of poor water solubility and low utilization. Therefore, this study not only elaborated the new mechanism of NAP inhibiting CSCs, but also built NAP-loaded nanoprobes using apoptotic tumor-derived microparticles (TMPs) as carriers to combine diagnose and treat of colon cancer and lessen the adverse effects of NAP.

RESULTS

The study discovered a new mechanism for NAP inhibiting tumors. NAP, in addition to inhibiting STAT3, may also inhibit STAT1, thereby inhibiting the expression of CD44, and the stemness of colon cancer. N₃-TMPs@NAP was successfully synthesized, and it possessed a lipid bilayer with a particle size of 220.13 ± 4.52 nm, as well as strong tumor binding ability and anti-tumor effect in vitro. In static PET/CT imaging studies, the tumor was clearly visible and showed higher uptake after N₃-TMPs@NAP injection than after oral administration. The average tumor volume and weight of the N₃-TMPs@NAP group on day 14 of the treatment studies were computed to be 270.55 ± 107.59 mm³ and 0.30 ± 0.12 g, respectively. These values were significantly lower than those of the other groups. Additionally, N₃-TMPs@NAP might prevent colon cancer from spreading to the liver. Furthermore, due to TMPs' stimulation of innate immunity, N₃-TMPs@NAP might stimulate anti-tumor.

CONCLUSIONS

As a combined diagnostic and therapeutic nanoprobe, N₃-TMPs@NAP could successfully conduct PET/CT imaging, suppress CSCs, and synergistically stimulate anticancer immune responses. Additionally, this nanoprobe might someday be employed in clinical situations because TMPs for it can be produced from human tissue and NAP has FDA approval.

Optimized Cationic Lipid-assisted Nanoparticle for Delivering CpG Oligodeoxynucleotides to Treat Hepatitis B Virus Infection

PURPOSE

Hepatitis B virus (HBV) infection is such a global health problem that hundreds of millions of people are HBV carriers. Current anti-viral agents can inhibit HBV replication, but can hardly eradicate HBV. Cytosine-phosphate-guanosine (CpG) oligodeoxynucleotides (ODNs) are an adjuvant that can activate plasmacytoid dendritic cells (pDCs) and conventional dendritic cells (cDCs) to induce therapeutic immunity for HBV eradication. However, efficient delivery of CpG ODNs into pDCs and cDCs remains a challenge. In this study, we constructed a series of cationic lipid-assisted nanoparticles (CLANs) using different cationic lipids to screen an optimal nanoparticle for delivering CpG ODNs into pDCs and cDCs.

METHODS

We constructed different CLAN_CpG using six cationic lipids and analyzed the cellular uptake of different CLAN_CpG by pDCs and cDCs in vitro and in vivo, and further analyzed the efficiency of different CLAN_CpG for activating pDCs and cDCs in both wild type mice and HBV-carrier mice.

RESULTS

We found that CLAN fabricated with 1,2-Dioleoyl-3-trimethylammonium propane (DOTAP) showed the highest efficiency for delivering CpG ODNs into pDCs and cDCs, resulting in strong therapeutic immunity in HBV-carrier mice. By using CLAN_CpG as an immune adjuvant in combination with the injection of recombinant hepatitis B surface antigen (rHBsAg), HBV was successfully eradicated and the chronic liver inflammation in HBV-carrier mice was reduced.

CONCLUSION

We screened an optimized CLAN fabricated with DOTAP for efficient delivery of CpG ODNs to pDCs and cDCs, which can act as a therapeutic vaccine adjuvant for treating HBV infection.

Cell-Based Drug Delivery Systems Participate in the Cancer Immunity Cycle for Improved Cancer Immunotherapy

Immunotherapy aims to activate the cancer patient's immune system for cancer therapy. The whole process of the immune system against cancer referred to as the "cancer immunity cycle", gives insight into how drugs can be designed to affect every step of the anticancer immune response. Cancer immunotherapy such as immune checkpoint inhibitor (ICI) therapy, cancer vaccines, as well as small molecule modulators has been applied to fight various cancers. However, the effect of immunotherapy in clinical applications is still unsatisfactory due to the limited response rate and immune-related adverse events. Mounting evidence suggests that cell-based drug delivery systems (DDSs) with low immunogenicity, superior targeting, and prolonged circulation have great potential to improve the efficacy of cancer immunotherapy. Therefore, with the rapid development of cell-based DDSs, understanding their important roles in various stages of the cancer immunity cycle guides the better design of cell-based cancer immunotherapy. Herein, an overview of how cell-based DDSs participate in cancer immunotherapy at various stages is presented and an outlook on possible challenges of clinical translation and application in future development.

Engineering magnetic nano-manipulators for boosting cancer immunotherapy

Cancer immunotherapy has shown promising therapeutic results in the clinic, albeit only in a limited number of cancer types, and its efficacy remains less than satisfactory. Nanoparticle-based approaches have been shown to increase the response to immunotherapies to address this limitation. In particular, magnetic nanoparticles (MNPs) as a powerful manipulator are an appealing option for comprehensively regulating the immune system in vivo due to their unique magnetically responsive properties and high biocompatibility. This review focuses on assessing the potential applications of MNPs in enhancing tumor accumulation of immunotherapeutic agents and immunogenicity, improving immune cell infiltration, and creating an immunotherapy-sensitive environment. We summarize recent progress in the application of MNP-based manipulators to augment the efficacy of immunotherapy, by MNPs and their multiple magnetically responsive effects under different types of external magnetic field. Furthermore, we highlight the mechanisms underlying the promotion of antitumor immunity, including magnetically actuated delivery and controlled release of immunotherapeutic agents, tracking and visualization of immune response in real time, and magnetic regulation of innate/adaptive immune cells. Finally, we consider perspectives and challenges in MNP-based immunotherapy.

Extracellular-Vesicle-Based Drug Delivery Systems for Enhanced Antitumor Therapies through Modulating the Cancer-Immunity Cycle

Although immunotherapy harnessing activity of the immune system against tumors has made great progress, the treatment efficacy remains limited in most cancers. Current anticancer immunotherapy is primarily based on T-cell-mediated cellular immunity, which highly relies on efficiency of triggering the cancer-immunity cycle, namely, tumor antigen release, antigen presentation by antigen presenting cells, T cell activation, recruitment and infiltration of T cells into tumors, and recognition and killing of tumor cells by T cells. Unfortunately, these immunotherapies are restricted by inefficient drug delivery and acting on only a single step of the cancer-immunity cycle. Due to high biocompatibility, low immunogenicity, intrinsic cell targeting, and easy chemical and genetic manipulation, extracellular vesicle (EV)-based drug delivery systems are widely used to amplify anticancer immune responses by serving as an integrated platform for multiple drugs or therapeutic strategies to synergistically activate several steps of cancer-immunity cycle. This review summarizes various mechanisms related to affecting cancer-immunity cycle disorders. Meanwhile, preparation and application of EV-based drug delivery systems in modulating cancer-immunity cycle are introduced, especially in the improvement of T cell recruitment and infiltration into tumors. Finally, opportunities and challenges of EV-based drug delivery systems in translational clinical applications are briefly discussed.

Prodrug nanoparticles potentiate tumor chemo-immunometabolic therapy by disturbing oxidative stress

Constant oxidative stress and lactate accumulation are two main causes of tumor immunosuppression, their concurrent reduction plays a dominant role in effective antitumor immunity, but remains challenging. Herein, reactive oxygen species (ROS) responsive prodrug nanoparticles (designed as DHCRJ) are constructed for metabolic amplified chemo-immunotherapy against triple-negative breast cancer (TNBC) by modulating oxidative state and hyperglycolysis. Specifically, DHCRJ is prepared by the self-assembly of DOX prodrug-tethered ROS consuming bond-bridged copolymers with the loading of bromodomain-containing protein 4 inhibitor (BRD4i) JQ1. Interestingly, the nanoparticle polymer network could reduce ROS to relieve tumor hypoxia and realize the dense-to-loose structure inversion arising from ROS-triggered network collapse, which favors JQ1 release and hyaluronidase (Hyal)-activatable DOX prodrugs generation. More importantly, disruption of oxidative stress decreases glucose uptake and assists JQ1 to down-regulate oncogene c-Myc driven tumor glycolysis for blocking the source of lactate and reshaping immunosuppressive tumor microenvironment (ITME). Meanwhile, benefiting from the synergistic effect of DOX prodrugs and JQ1, DHCRJ is able to facilitate tumor immunogenicity and potentiate systemic immune responses through antigen processing and presentation pathway. In this manner, DHCRJ significantly suppresses tumor growth and metastasis with prolonged survival. Collectively, this study represents a proof of concept antioxidant-enhanced chemo-immunometabolic therapy strategy using ROS-reducing nanoparticles for efficient synergistic therapeutic modality of TNBC.

Phenylboronic ester-modified polymeric nanoparticles for promoting TRP2 peptide antigen delivery in cancer immunotherapy

The tremendous development of peptide-based cancer vaccine has attracted incremental interest as a powerful approach in cancer management, prevention and treatment. As successful as tumor vaccine has been, major challenges associated with achieving efficient immune response against cancer are (1) drainage to and retention in lymph nodes; (2) uptake by dendritic cells (DCs); (3) activation of DCs. In order to overcome these barriers, here we construct PBE-modified TRP2 nanovaccine, which comprises TRP2 peptide tumor antigen and diblock copolymer PEG-b-PAsp grafted with phenylboronic ester (PBE). We confirmed that this TRP2 nanovaccine can be effectively trapped into lymph node, uptake by dendritic cells and induce DC maturation, relying on increased negative charge, ROS response and pH response. Consistently, this vehicle loaded with TRP2 peptide could boost the strongest T cell immune response against melanoma in vivo and potentiate antitumor efficacy both in tumor prevention and tumor treatment without any exogenous adjuvant. Furthermore, the TRP2 nanovaccine can suppress the tumor growth and prolong animal survival time, which may result from its synergistic effect of inhibiting tumor immunosuppression and increasing cytotoxic lymphocyte (CTL) response. Hence this type of PBE-modified nanovaccine would be widely used as a simple, safe and robust platform to deliver other antigen in cancer immunotherapy.

Phospholipid-Membrane-Based Nanovesicles Acting as Vaccines for Tumor Immunotherapy: Classification, Mechanisms and Applications

Membrane vesicles, a group of nano- or microsized vesicles, can be internalized or interact with the recipient cells, depending on their parental cells, size, structure and content. Membrane vesicles fuse with the target cell membrane, or they bind to the receptors on the cell surface, to transfer special effects. Based on versatile features, they can modulate the functions of immune cells and therefore influence immune responses. In the field of tumor therapeutic applications, phospholipid-membrane-based nanovesicles attract increased interest. Academic institutions and industrial companies are putting in effort to design, modify and apply membrane vesicles as potential tumor vaccines contributing to tumor immunotherapy. This review focuses on the currently most-used types of membrane vesicles (including liposomes, bacterial membrane vesicles, tumor- and dendritic-cell-derived extracellular vesicles) acting as tumor vaccines, and describes the classification, mechanism and application of these nanovesicles.

Toll-like receptor 9 agonists and combination therapies: strategies to modulate the tumour immune microenvironment for systemic anti-tumour immunity

Over the past decade, tremendous progress has taken place in tumour immunotherapy, relying on the fast development of combination therapy strategies that target multiple immunosuppressive signaling pathways in the immune system of cancer patients to achieve a high response rate in clinical practice. Toll-like receptor 9 (TLR9) agonists have been extensively investigated as therapeutics in monotherapy or combination therapies for the treatment of cancer, infectious diseases and allergies. TLR9 agonists monotherapy shows limited efficacy in cancer patients; whereas, in combination with other therapies including antigen vaccines, radiotherapies, chemotherapies and immunotherapies exhibit great potential. Synthetic unmethylated CpG oligodeoxynucleotide (ODN), a commonly used agonist for TLR9, stimulate various antigen-presenting cells in the tumour microenvironment, which can initiate innate and adaptive immune responses. Novel combination therapy approaches, which co-deliver immunostimulatory CpG-ODN with other therapeutics, have been tested in animal models and early human clinical trials to induce anti-tumour immune responses. In this review, we describe the basic understanding of TLR9 signaling pathway; the delivery methods in most studies; discuss the key challenges of each of the above mentioned TLR9 agonist-based combination immunotherapies and provide an overview of the ongoing clinical trial results from CpG-ODN based combination therapies in cancer patients.

In situ generation of micrometer-sized tumor cell-derived vesicles as autologous cancer vaccines for boosting systemic immune responses

Cancer vaccine, which can promote tumor-specific immunostimulation, is one of the most important immunotherapeutic strategies and holds tremendous potential for cancer treatment/prevention. Here, we prepare a series of nanoparticles composed of doxorubicin- and tyrosine kinase inhibitor-loaded and hyaluronic acid-coated dendritic polymers (termed HDDT nanoparticles) and find that the HDDT nanoparticles can convert various cancer cells to micrometer-sized vesicles (1.6-3.2 μm; termed HMVs) with ~100% cell-to-HMV conversion efficiency. We confirm in two tumor-bearing mouse models that the nanoparticles can restrain tumor growth, induce robust immunogenic cell death, and convert the primary tumor into an antigen depot by producing HMVs in situ to serve as personalized vaccines for cancer immunotherapy. Furthermore, the HDDT-healed mice show a strong immune memory effect and the HDDT treatment can realize long-term protection against tumor rechallenge. Collectively, the present work provides a general strategy for the preparation of tumor-associated antigen-containing vesicles and the development of personalized cancer vaccines.

Nanoparticle-Based Drug Delivery Systems Targeting Tumor Microenvironment for Cancer Immunotherapy Resistance: Current Advances and Applications

Cancer immunotherapy has shown impressive anti-tumor activity in patients with advanced and early-stage malignant tumors, thus improving long-term survival. However, current cancer immunotherapy is limited by barriers such as low tumor specificity, poor response rate, and systemic toxicities, which result in the development of primary, adaptive, or acquired resistance. Immunotherapy resistance has complex mechanisms that depend on the interaction between tumor cells and the tumor microenvironment (TME). Therefore, targeting TME has recently received attention as a feasibility strategy for re-sensitizing resistant neoplastic niches to existing cancer immunotherapy. With the development of nanotechnology, nanoplatforms possess outstanding features, including high loading capacity, tunable porosity, and specific targeting to the desired locus. Therefore, nanoplatforms can significantly improve the effectiveness of immunotherapy while reducing its toxic and side effects on non-target cells that receive intense attention in cancer immunotherapy. This review explores the mechanisms of tumor microenvironment reprogramming in immunotherapy resistance, including TAMs, CAFs, vasculature, and hypoxia. We also examined whether the application of nano-drugs combined with current regimens is improving immunotherapy clinical outcomes in solid tumors.

Engineered extracellular vesicles: A novel platform for cancer combination therapy and cancer immunotherapy

Extracellular vesicles (EVs), phospholipid membrane-bound vesicles, produced by most cells, contribute to cell-cell communication. They transfer several proteins, lipids, and nucleic acids between cells both locally and systemically. Owing to the biocompatibility and immune activity of EVs, therapeutic approaches using these vesicles as drug delivery systems are being developed. Different methods are used to design more effective engineered EVs, which can serve as smart tools in cancer therapy and immunotherapy. Recent progress in the field of targeted-cancer therapy has led to the gradual use of engineered EVs in combinational therapy to combat heterogeneous tumor cells and multifaceted tumor microenvironments. The high plasticity, loading ability, and genetic manipulation capability of engineered EVs have made them the ideal platforms to realize numerous combinations of cancer therapy approaches. From the combination therapy view, engineered EVs can co-deliver chemotherapy with various therapeutic agents to target tumor cells effectively, further taking part in immunotherapy-related cancer combination therapy. However, a greater number of studies were done in pre-clinical platforms and the clinical translation of these studies needs further scrutiny because some challenges are associated with the application of engineered EVs. Given the many therapeutic potentials of engineered EVs, this review discusses their function in various cancer combination therapy and immunotherapy-related cancer combination therapy. In addition, this review describes the opportunities and challenges associated with the clinical application of engineered EVs.

Novel insights into noncanonical open reading frames in cancer

With technological advances, previously neglected noncanonical open reading frames (nORFs) are drawing ever-increasing attention. However, the translation potential of numerous putative nORFs remains elusive, and the functions of noncanonical peptides have not been systemically summarized. Moreover, the relationship between noncanonical peptides and their counterpart protein or RNA products remains elusive and the clinical implementation of noncanonical peptides has not been explored. In this review, we highlight how recent technological advances such as ribosome profiling, bioinformatics approaches and CRISPR/Cas9 facilitate the research of noncanonical peptides. We delineate the features of each nORF category and the evolutionary process underneath the nORFs. Most importantly, we summarize the diversified functions of noncanonical peptides in cancer based on their subcellular location, which reflect their extensive participation in key pathways and essential cellular activities in cancer cells. Meanwhile, the equilibrium between noncanonical peptides and their corresponding transcripts or counterpart products may be dysregulated under pathological states, which is essential for their roles in cancer. Lastly, we explore their underestimated potential in clinical application as diagnostic biomarkers and treatment targets against cancer.

Identification and Validation of Genomic Subtypes and a Prognostic Model Based on Antigen-Presenting Cells and Tumor Microenvironment Infiltration Characteristics in Hepatocellular Carcinoma

Currently, the prognosis of hepatocellular carcinoma (HCC) is poor, and there is a lack of effective targeted therapy. As key mediators of the immune response, the prognostic value of antigen-presenting cells (APCs) in HCC still remains unclear. In this study, we aimed to identify APC-related genomic subtypes and develop a novel prognostic model in HCC. Our results indicated that overall survival (OS) and the level of immune infiltration significantly differed between different APC clusters. By analyzing the gene expression profile between APC clusters, APC-related genomic subtypes were identified. There was a significant difference in OS and tumor microenvironment infiltration in HCC patients with different genomic subtypes. With the aid of genomic subtypes, significantly differentially expressed genes were screened to generate a novel prognostic model. The risk score of the model had a significant positive correlation with APCs and was associated with immune checkpoint expressions. Through the clinical cohort collected from the First Affiliated Hospital of Wenzhou Medical University, the prognostic value of the risk score was further validated. Moreover, after the risk score and clinical characteristics were combined, a nomogram was constructed to evaluate the prognosis for HCC patients. In conclusion, we mainly identified the APC-related genomic subtypes and generated a novel prognostic model to improve the prognostic prediction and targeted therapy for HCC patients.

Nanoparticles mediated tumor microenvironment modulation: current advances and applications

The tumor microenvironment (TME) plays a key role in cancer development and emergence of drug resistance. TME modulation has recently garnered attention as a potential approach for reprogramming the TME and resensitizing resistant neoplastic niches to existing cancer therapies such as immunotherapy or chemotherapy. Nano-based solutions have important advantages over traditional platform and can be specifically targeted and delivered to desired sites. This review explores novel nano-based approaches aimed at targeting and reprogramming aberrant TME components such as macrophages, fibroblasts, tumor vasculature, hypoxia and ROS pathways. We also discuss how nanoplatforms can be combined with existing anti-tumor regimens such as radiotherapy, immunotherapy, phototherapy or chemotherapy to enhance clinical outcomes in solid tumors.

Microparticles: biogenesis, characteristics and intervention therapy for cancers in preclinical and clinical research

Extracellular vesicles (EVs), spherical biological vesicles, mainly contain nucleic acids, proteins, lipids and metabolites for biological information transfer between cells. Microparticles (MPs), a subtype of EVs, directly emerge from plasma membranes, and have gained interest in recent years. Specific cell stimulation conditions, such as ultraviolet and X-rays irradiation, can induce the release of MPs, which are endowed with unique antitumor functionalities, either for therapeutic vaccines or as direct antitumor agents. Moreover, the size of MPs (100–1000 nm) and their spherical structures surrounded by a lipid bilayer membrane allow MPs to function as delivery vectors for bioactive antitumor compounds, with favorable phamacokinetic behavior, immunostimulatory activity and biological function, without inherent carrier-specific toxic side effects. In this review, the mechanisms underlying MP biogenesis, factors that influence MP production, properties of MP membranes, size, composition and isolation methods of MPs are discussed. Additionally, the applications and mechanisms of action of MPs, as well as the main hurdles for their applications in cancer management, are introduced.

Engineered extracellular vesicles: potentials in cancer combination therapy

Extracellular vesicles (EVs) are a group of secretory vesicles with cell-derived membrane and contents. Due to the cargo delivery capability, EVs can be designed as drug delivery platforms for cancer therapy. Biocompatibility and immune compatibility endow EVs with unique advantages compared with other nanocarriers. With the development of this field, multiple ingenious modification methods have been developed to obtain engineered EVs with desired performance. Application of engineered EVs in cancer therapy has gradually shifted from monotherapy to combinational therapy to fight against heterogeneous cancer cells and complex tumor microenvironment. In addition, the strong plasticity and load capacity of engineered EV make it potential to achieve various combinations of cancer treatment methods. In this review, we summarize the existing schemes of cancer combination therapy realized by engineered EVs, highlight the mechanisms and representative examples of these schemes and provide guidance for the future application of engineered EVs to design more effective cancer combination treatment plans.

Nano dimensions/adjuvants in COVID-19 vaccines

A favorable outcome of the COVID-19 crisis might be achieved with massive vaccination. The proposed vaccines contain several different vaccine active principles (VAP), such as inactivated virus, antigen, mRNA, and DNA, which are associated with either standard adjuvants or nanomaterials (NM) such as liposomes in Moderna's and BioNTech/Pfizer's vaccines. COVID-19 vaccine adjuvants may be chosen among liposomes or other types of NM composed for example of graphene oxide, carbon nanotubes, micelles, exosomes, membrane vesicles, polymers, or metallic NM, taking inspiration from cancer nano-vaccines, whose adjuvants may share some of their properties with those of viral vaccines. The mechanisms of action of nano-adjuvants are based on the facilitation by NM of targeting certain regions of immune interest such as the mucus, lymph nodes, and zones of infection or blood irrigation, the possible modulation of the type of attachment of the VAP to NM, in particular VAP positioning on the NM external surface to favor VAP presentation to antigen presenting cells (APC) or VAP encapsulation within NM to prevent VAP degradation, and the possibility to adjust the nature of the immune response by tuning the physico-chemical properties of NM such as their size, surface charge, or composition. The use of NM as adjuvants or the presence of nano-dimensions in COVID-19 vaccines does not only have the potential to improve the vaccine benefit/risk ratio, but also to reduce the dose of vaccine necessary to reach full efficacy. It could therefore ease the overall spread of COVID-19 vaccines within a sufficiently large portion of the world population to exit the current crisis.

Hyperthermia based individual in situ recombinant vaccine enhances lymph nodes drainage for de novo antitumor immunity

The continuing challenges that limit effectiveness of tumor therapeutic vaccines were high heterogeneity of tumor immunogenicity, low bioactivity of antigens, as well as insufficient lymph nodes (LNs) drainage of antigens and adjuvants. Transportation of in situ neoantigens and adjuvants to LNs may be an effective approach to solve the abovementioned problems. Therefore, an FA-TSL/AuNCs/SV nanoplatform was constructed by integrating simvastatin (SV) adjuvant loaded Au nanocages (AuNCs) as cores (AuNCs/SV) and folic acid modified thermal-sensitive liposomes (FA-TSL) as shells to enhance de novo antitumor immunity. After accumulation in tumor guided by FA, AuNCs mediated photothermal therapy (PTT) induced the release of tumor-derived protein antigens (TDPAs) and the shedding of FA-TSL. Exposed AuNCs/SV soon captured TDPAs to form in situ recombinant vaccine (AuNCs/SV/TDPAs). Subsequently, AuNCs/SV/TDPAs could efficiently transport to draining LNs owing to the hyperthermia induced vasodilation effect and small particle size, achieving co-delivery of antigens and adjuvant for initiation of specific T cell response. In melanoma bearing mice, FA-TSL/AuNCs/SV and laser irradiation effectively ablated primary tumor, against metastatic tumors and induced immunological memory. This approach served a hyperthermia enhanced platform drainage to enable robust personalized cancer vaccination.

Metal-free bioorthogonal click chemistry in cancer theranostics

Bioorthogonal chemistry is a powerful tool to site-specifically activate drugs in living systems. Bioorthogonal reactions between a pair of biologically reactive groups can rapidly and specifically take place in a mild physiological milieu without perturbing inherent biochemical processes. Attributed to their high selectivity and efficiency, bioorthogonal reactions can significantly decrease background signals in bioimaging. Compared with metal-catalyzed bioorthogonal click reactions, metal-free click reactions are more biocompatible without the metal catalyst-induced cytotoxicity. Although a great number of bioorthogonal chemistry-based strategies have been reported for cancer theranostics, a comprehensive review is scarce to highlight the advantages of these strategies. In this review, recent progress in cancer theranostics guided by metal-free bioorthogonal click chemistry will be depicted in detail. The elaborate design as well as the advantages of bioorthogonal chemistry in tumor theranostics are summarized and future prospects in this emerging field are emphasized.

Binary regulation of the tumor microenvironment by a pH-responsive reversible shielding nanoplatform for improved tumor chemo-immunotherapy

The limited infiltration of specific T cells in an immunosuppressive microenvironment is a major challenge for cancer immunotherapy. Reversing tumor microenvironment and inducing an antitumor immune response are crucial for cancer therapy. Here, phenylboronic acid (PBA) derivative-stabilized ultrasmall platinum nanoparticles (PBA-Pt) and dextran-coated BLZ-945 nanoparticles (DNPs) were co-assembled through a pH-responsive borate ester bond to construct a versatile reversible shielding multifunctional nanoplatform (Pt@DNPs) for the first time. Pt@DNPs dissociated into two individual components, namely PBA-Pt and DNPs, in the tumor acid microenvironment. Both in vitro and in vivo studies revealed that Pt@DNPs induced immunogenic cell death (ICD) (through multimechanisms involving Pt^Ⅱ release and a multienzyme catalytic process by PBA-Pt) and relieved immunosuppressive microenvironment (depletion of tumor-associated macrophages by BLZ-945), which led to tumor-associated antigen release, maturation of dendritic cells, and infiltration of cytotoxic T cells for efficient antitumor immune response against both primary tumor and pulmonary metastatic tumor nodules. Therefore, Pt@DNPs is a promising option for cancer chemo-immunotherapy. STATEMENT OF SIGNIFICANCE: A versatile reversible shielding multifunctional nanoplatform (Pt@DNPs) was engineered for the first time for combinational cancer chemo-immunotherapy. Multimechanisms involving induction of immunogenic cell death by PBA-Pt and sufficient TAM depletion by DNPs could efficiently relieve tumor immunosuppressive microenvironment and activate the antitumor immune response. The synergistic effect not only increased the infiltration of specific T cells in primary tumor, but it also induced a strong immune response against pulmonary metastatic nodules. Collectively, this nanoplatform may represent a promising strategy for combinational chemo-immunotherapy for cancers.

Tumor associated macrophage and microbe: The potential targets of tumor vaccine delivery

The occurrence and development of tumors depend on the tumor microenvironment (TME), which is made of various immune cells, activated fibroblasts, basement membrane, capillaries, and extracellular matrix. Tumor associated macrophages (TAMs) and microbes are important components in TME. Tumor cells can recruit and educate TAMs and microbes, and the hijacked TAMs and microbes can promote the progression of tumor reciprocally. Tumor vaccine delivery remodeling TME by targeting TAM and microbes can not only enhance the specificity and immunogenicity of antigens, but also contribute to the regulation of TME. Tumor vaccine design benefits from nanotechnology which is a suitable platform for antigen and adjuvant delivery to catalyze new candidate vaccines applying to clinical therapy at unparalleled speed. In view of the characteristics and mechanisms of TME development, vaccine delivery targeting and breaking the malignant interactions among tumor cells, TAMs, and microbes may serve as a novel strategy for tumor therapy.

Remodeling Macrophages by an Iron Nanotrap for Tumor Growth Suppression

Tumor-associated macrophages (TAMs) that infiltrate in most tumor tissues are closely correlated with proliferation and metastasis of tumor cells. Immunomodulation of TAMs from pro-tumorigenic M2 phenotype to anti-tumorigenic M1 phenotype is crucial for oncotherapy. Herein, an iron nanotrap was utilized to remodel TAMs for tumor growth inhibition. In the formulation, the ultrasmall nanotrap could capture and targetedly transport endogenous iron into TAMs even inside the tumor. Upon exposing to the lysosomal acidic conditions and intracellular H₂O₂, iron was released from the nanotrap and produced the generation of oxidative stress, which could reprogram TAMs. The activated M1 macrophages could induce immune responses and suppress tumor growth ultimately. Meanwhile, this metal-free nanotrap with degradability by H₂O₂ possessed favorable biocompatibility. Our work would present potential opportunities of utilizing endogenous substances for secure treatment of various diseases.

DNA Nanodevice-Based Drug Delivery Systems

DNA, a natural biological material, has become an ideal choice for biomedical applications, mainly owing to its good biocompatibility, ease of synthesis, modifiability, and especially programmability. In recent years, with the deepening of the understanding of the physical and chemical properties of DNA and the continuous advancement of DNA synthesis and modification technology, the biomedical applications based on DNA materials have been upgraded to version 2.0: through elaborate design and fabrication of smart-responsive DNA nanodevices, they can respond to external or internal physical or chemical stimuli so as to smartly perform certain specific functions. For tumor treatment, this advancement provides a new way to solve the problems of precise targeting, controllable release, and controllable elimination of drugs to a certain extent. Here, we review the progress of related fields over the past decade, and provide prospects for possible future development directions.

A multimodal strategy of Fe3O4@ZIF-8/GOx@MnO2 hybrid nanozyme via TME modulation for tumor therapy

Weak acidity (6.5-6.9) and limited H₂O₂ level in the tumor microenvironment (TME) usually impact the therapeutic effect of chemodynamic therapy (CDT) for cancer. A Specific TME promotes the formation of an immunosuppressive microenvironment and results in high rate of recurrence and metastasis of cancer. Fe₃O₄@ZIF-8/GOx@MnO₂ multi-layer core shell nanostructure was constructed as a hybrid nanozyme. After magnetic targeting of the tumor site, the outermost MnO₂ shell catalyzed H₂O₂ in TME to produce O₂ and was broken due to the reaction with glutathione. Due to the acid response, the ZIF-8 layer would crack and release glucose oxidase (GOx) and Fe₃O₄. The generated O₂ was utilized by GOx in starvation therapy to consume glucose and produce H₂O₂ and gluconic acid. The Fenton reaction efficiency of Fe(II) was improved by the increased H₂O₂ concentration and the enhanced acidity in TME. At the same time, the intrinsic photothermal effect of Fe₃O₄ upon 808 nm laser irradiation promoted the activity of MnO₂ and GOx as oxidase, and Fe(II) as catalase-like, and ablated the primary tumor. Moreover, the hybrid nanozyme can facilitate the transformation of M2-type macrophages to M1-type, and strong systemic antitumor immune effect was induced. A synergy of multiple therapeutic modes including starvation therapy, CDT, photothermal therapy (PTT), and immunotherapy can be realized in the hybrid nanozyme for tumor therapy.

Intratumor heterogeneity: the hidden barrier to immunotherapy against MSI tumors from the perspective of IFN-γ signaling and tumor-infiltrating lymphocytes

In this era of precision medicine, with the help of biomarkers, immunotherapy has significantly improved prognosis of many patients with malignant tumor. Deficient mismatch repair (dMMR)/microsatellite instability (MSI) status is used as a biomarker in clinical practice to predict favorable response to immunotherapy and prognosis. MSI is an important characteristic which facilitates mutation and improves the likelihood of a favorable response to immunotherapy. However, many patients with dMMR/MSI still respond poorly to immunotherapies, which partly results from intratumor heterogeneity propelled by dMMR/MSI. In this review, we discuss how dMMR/MSI facilitates mutations in tumor cells and generates intratumor heterogeneity, especially through type II interferon (IFN-γ) signaling and tumor-infiltrating lymphocytes (TILs). We discuss the mechanism of immunotherapy from the perspective of dMMR/MSI, molecular pathways and TILs, and we discuss how intratumor heterogeneity hinders the therapeutic effect of immunotherapy. Finally, we summarize present techniques and strategies to look at the tumor as a whole to design personalized regimes and achieve favorable prognosis.

Tackling TAMs for Cancer Immunotherapy: It's Nano Time

The tumor microenvironment (TME) is a highly complex environment that surrounds tumors. Interactions between cancer cells/non-cancerous cells and cells/non-cell components in the TME support tumor initiation, development, and metastasis. Of the cell types in the TME, tumor-associated macrophages (TAMs) have gained attention owing to their crucial roles in supporting tumors and conferring therapy resistance. Recent developments in nanotechnology raise opportunities for the application of nano targeted drug-delivery systems (Nano-TDDS) in cancer therapy. We focus our discussion on current knowledge of TAMs, and describe recent examples of Nano-TDDS-based TAM modulation, highlighting strategies to overcome in vivo delivery barriers associated with the TME and their potential for clinical translation.

Immune Cell Modulation of the Extracellular Matrix Contributes to the Pathogenesis of Pancreatic Cancer

Pancreatic ductal adenocarcinoma (PDAC) is a highly lethal malignancy with a five-year survival rate of only 9%. PDAC is characterized by a dense, fibrotic stroma composed of extracellular matrix (ECM) proteins. This desmoplastic stroma is a hallmark of PDAC, representing a significant physical barrier that is immunosuppressive and obstructs penetration of cytotoxic chemotherapy agents into the tumor microenvironment (TME). Additionally, dense ECM promotes hypoxia, making tumor cells refractive to radiation therapy and alters their metabolism, thereby supporting proliferation and survival. In this review, we outline the significant contribution of fibrosis to the pathogenesis of pancreatic cancer, with a focus on the cross talk between immune cells and pancreatic stellate cells that contribute to ECM deposition. We emphasize the cellular mechanisms by which neutrophils and macrophages, specifically, modulate the ECM in favor of PDAC-progression. Furthermore, we investigate how activated stellate cells and ECM influence immune cells and promote immunosuppression in PDAC. Finally, we summarize therapeutic strategies that target the stroma and hinder immune cell promotion of fibrogenesis, which have unfortunately led to mixed results. An enhanced understanding of the complex interactions between the pancreatic tumor ECM and immune cells may uncover novel treatment strategies that are desperately needed for this devastating disease.

The Combination of Liposomes and Metallic Nanoparticles as Multifunctional Nanostructures in the Therapy and Medical Imaging-A Review

Nanotechnology has introduced a new quality and has definitely developed the possibilities of treating and diagnosing various diseases. One of the scientists' interests is liposomes and metallic nanoparticles (LipoMNPs)-the combination of which has introduced new properties and applications. However, the field of creating hybrid nanostructures consisting of liposomes and metallic nanoparticles is relatively little understood. The purpose of this review was to compile the latest reports in the field of treatment and medical imaging using of LipoMNPs. The authors focused on presenting this issue in the direction of improving the used conventional treatment and imaging methods. Most of all, the nature of bio-interactions between nanostructures and cells is not sufficiently taken into account. As a result, overcoming the existing limitations in the implementation of such solutions in the clinic is difficult. We concluded that hybrid nanostructures are used in a very wide range, especially in the treatment of cancer and magnetic resonance imaging. There were also solutions that combine treatments with simultaneous imaging, creating a theragnostic approach. In the future, researchers should focus on the description of the biological interactions and the long-term effects of the nanostructures to use LipoMNPs in the treatment of patients.

Enhanced Antitumor Immune Responses via a Self-Assembled Carrier-Free Nanovaccine

Nanovaccines have emerged as promising agents for cancer immunotherapy. However, insufficient antitumor immunity caused by inefficient antigen/adjuvant loading and complicated preparation processes are the major obstacles that limit their clinical application. Herein, two adjuvants, monophosphatidyl A (MPLA) and CpG ODN, with antigens were designed into a nanovaccine to overcome the above obstacles. This nanovaccine was constructed with adjuvants (without additional materials) through facile self-assembly, which not only ensured a high loading efficacy and desirable safety but also facilitated clinical translation for convenient fabrication. More importantly, the selected adjuvants could achieve a notable immune response through synergistic activation of Toll-like receptor 4 (TLR4) and TLR9 signaling pathways, and the resulting nanovaccine remarkably inhibited the tumor growth and prolonged the survival of tumor-implanted mice. This nanovaccine system provides an effective strategy to construct vaccines for cancer immunotherapy.

Cascade Catalytic Nanoplatform Based on "Butterfly Effect" for Enhanced Immunotherapy

The unique tumor microenvironment (TME) characteristics such as immunosuppression impeded traditional cancer treatments. In contrast, developing cascade catalytic nanoplatforms by fully making use of substances in TME for cancer therapy may deserve full credit. Herein, a cascade catalytic nanoplatform based on glucose oxidase (GOD) modified mesoporous iron oxide nanoparticles (IONP) loaded with Artemisinin (ART) is developed, which is designed as IONP-GOD@ART. GOD can catalyze the oxidization of glucose into gluconic acid and H₂ O₂ , which not only realizes tumor starvation therapy, but also provides H₂ O₂ for IONP mediated Fenton reaction. Simultaneously, mesoporous IONP releases Fe²⁺ and Fe³⁺ ions in acidic TME. On the one hand, iron ions undergo Fenton reaction to generate hydroxyl radicals for chemodynamic therapy. On the other hand, the endoperoxide bridge in ART is broken in presence of Fe²⁺ and further generates reactive oxygen species (ROS) to achieve therapeutic purpose. In this sense, IONP-GOD@ART manipulates TME characteristics and leads to "butterfly effect", which brings out a large amount of ROS for eliciting immunogenic cell death, inducing M1-TAMs polarization, and further reprogramming immunosuppressive TME for enhanced immunotherapy. By this delicate design, the cascade catalytic nanoplatform of IONP-GOD@ART realizes potent cancer immunotherapy for tumor regression and metastasis prevention.

On-demand responsive nanoplatform mediated targeting of CAFs and down-regulating mtROS-PYK2 signaling for antitumor metastasis

The desmoplastic tumor microenvironment (DTME), including overexpressed stromal cells and extracellular matrix, formed the first barrier for the accumulation and penetration of nanoparticles in tumors, which compromised the therapeutic efficacy and prognosis. In some metastatic cells, overactivity of the tricarboxylic cycle could overload the electron transport chain resulting in increased mtROS production, which triggered the mitochondria-driven tumor migration and metastasis. Hence, we developed HPBC@TRP/NPs for down-regulating the mtROS-PYK2 pathway and remodeling the DTME to inhibit tumor growth and metastasis for the first time. TPP-RSV prodrugs were synthesized and targeted at mitochondria, resulting in the scavenging of mtROS, lower PYK2 expression, and activation of the mitochondria-driven apoptotic pathway. Pirfenidone fully remodeled the DTME through inhibiting the expression of CAFs, hyaluronan and collagen I, thereby reducing IFP, eliminating the immunosuppressive microenvironment by decreasing the expression of TGF-β, and increasing the infiltration of cytotoxic T lymphocytes. The combination therapy of different mechanisms via targeting the mtROS-PYK2 pathway and CAFs might provide deeper insights into the inhibition of malignant breast cancer growth and metastasis.