In Situ Tumor Vaccine for Lymph Nodes Delivery and Cancer Therapy Based on Small Size Nanoadjuvant

Lymph node metastasis in cancer: Clearing the clouds to see the dawn

Lymph node metastasis (LNM) is often regarded as an indicator of poor prognosis in various cancers. Despite over three centuries of exploration since its discovery, the molecular mechanisms underlying LNM remain inconclusive. This review summarizes the molecular mechanisms of LNM, using the "PUMP+" principle for clarification. Pathological examination remains the gold standard for LNM diagnosis, yet there is a need to explore early diagnostic strategies that can effectively improve patient outcomes. With the advent of immunotherapy, discussions on the fate of lymph nodes (LN) have emerged, emphasizing the importance of preserving LN integrity prior to immunotherapy. This, in turn, poses higher demands for diagnostic accuracy and precision treatment of LNM. This review comprehensively discusses the molecular mechanisms, diagnostic methods, and treatment strategies for cancer lymph node metastasis, along with current bottlenecks and future directions in this field.

ROS-Responsive Injectable Hydrogel Loaded with SLC7A11-modRNA Inhibits Ferroptosis and Mitigates Intervertebral Disc Degeneration in Rats

Intervertebral disc degeneration (IVDD) is the primary cause of low back pain, with oxidative stress being a recognized factor that causes its development. Presently, low back pain imposes a significant global economic burden. However, the effectiveness of treatments for IVDD remains extremely limited. Therefore, this study aims to explore innovative and effective IVDD treatments by focusing on oxidative stress as a starting point. In this study, an injectable reactive oxygen species-responsive hydrogel (PVA-tsPBA@SLC7A11 modRNA) is developed, designed to achieve rapid loading and selective release of chemically synthesized modified mRNA (modRNA). SLC7A11 modRNA is specifically used to upregulate the expression of the ferroptosis marker SLC7A11. The local injection of PVA-tsPBA@SLC7A11 modRNA into the degenerated intervertebral disc (IVD) results in the cleavage of PVA-tsPBA, leading to the release of enclosed SLC7A11 modRNA. The extent of SLC7A11 modRNA release is directly proportional to the severity of IVDD, ultimately ameliorating IVDD by inhibiting ferroptosis in nucleus pulposus cells (NPCs). This study proposes an innovative system of PVA-tsPBA hydrogel-encapsulated modRNA, representing a potential novel treatment strategy for patients with early-stage IVDD.

Nanoreactors with Cascade Catalytic Activity Reprogram the Tumor Microenvironment for Enhanced Immunotherapy by Synchronously Regulating Treg and Macrophage Cells

Immunotherapy has been extensively utilized and studied as a prominent therapeutic strategy for tumors. However, the presence of a hypoxic immunosuppressive tumor microenvironment significantly reduces the efficacy of the treatment, thus impeding its application. In addition, the hypoxic microenvironment can also lead to the enrichment of immunosuppressive cells and reduce the effectiveness of tumor immunotherapy; nanoparticles with biocatalytic activity have the ability to relieve hypoxia in tumor tissues and deliver drugs to target cells and have been widely concerned and applied in the field of tumor therapy. The present study involved the development of a dual nanodelivery system that effectively targets the immune system to modify the tumor microenvironment (TME). The nanodelivery system was developed by incorporating R848 and Imatinib (IMT) into Pt nanozyme loaded hollow polydopamine (P@HP) nanocarriers. Subsequently, their surface was modified with specifically targeted peptides that bind to M2-like macrophages and regulatory T (Treg) cells, thereby facilitating the precise targeting of these cells. When introduced into the tumor model, the nanocarriers were able to selectively target immune cells in tumor tissue, causing M2-type macrophages to change into the M1 phenotype and reducing Treg activation within the tumor microenvironment. In addition, the carriers demonstrated exceptional biocatalytic activity, effectively converting H2O2 into oxygen and water at the tumor site while the drug was active, thereby alleviating the hypoxic inhibitory conditions present in the tumor microenvironment. Additionally, this further enhanced the infiltration of M1-type macrophages and cytotoxic T lymphocytes. Moreover, when used in conjunction with immune checkpoint therapy, the proposed approach demonstrated enhanced antitumor immunotherapeutic effects. The bimodal targeted immunotherapeutic strategy developed in the present study overcomes the drawbacks of traditional immunotherapy approaches while offering novel avenues for the treatment of cancer.

Dynamic Covalent Hydrogel as a Single-Dose Vaccine Adjuvant for Sustained Antigen Release and Significantly Elevated Humoral Immunity

Vaccine is the most important way for fighting against infection diseases. However, multiple injections and unsatisfied immune responses are the main obstacles for current vaccine application. Herein, a dynamic covalent hydrogel (DCH) is used as a single-dose vaccine adjuvant for eliciting robust and sustained humoral immunity. By adjusting the mass ratio of the DCH gel, 10-30 d constant release of the loaded recombinant protein antigens is successfully realized, and it is proved that sustained release of antigens can significantly improve the vaccine efficacy. When loading SARS-CoV-2 RBD (Wuhan and Omicron BA.1 strains) antigens into this DCH gel, an over 32 000 times and 8000 times improvement is observed in antigen-specific antibody titers compared to conventional Aluminum adjuvanted vaccines. The universality of this DCH gel adjuvant is confirmed in a Nipah G antigen test as well as a H1N1 influenza virus antigen test, with much improved protection of C57BL/6 mice against H1N1 virus infection than conventional Aluminum adjuvanted vaccines. This sustainably released, single-dose DCH gel adjuvant provides a new promising option for designing next-generation infection vaccines.

Lymphoid organ-targeted nanomaterials for immunomodulation of cancer, inflammation, and beyond

Nanomaterials exhibit significant potential for stimulating immune responses, offering both local and systemic modulation across a variety of diseases. The lymphoid organs, such as the spleen and lymph nodes, are home to various immune cells, including monocytes and dendritic cells, which contribute to both the progression and prevention/treatment of diseases. Consequently, many nanomaterial formulations are being rationally designed to target these organs and engage with specific cell types, thereby inducing therapeutic and protective effects. In this review, we explore crucial cellular interactions and processes involved in immune regulation and highlight innovative nano-based immunomodulatory approaches. We outline essential considerations in nanomaterial design with an emphasis on their impact on biological interactions, targeting capabilities, and treatment efficacy. Through selected examples, we illustrate the strategic targeting of therapeutically active nanomaterials to lymphoid organs and the subsequent immunomodulation for infection resistance, inflammation suppression, self-antigen tolerance, and cancer immunotherapy. Additionally, we address current challenges, discuss emerging topics, and share our outlook on future developments in the field.

Engineered Bacteriophage-Based In Situ Vaccine Remodels a Tumor Microenvironment and Elicits Potent Antitumor Immunity

In situ vaccines (ISVs) utilize the localized delivery of chemotherapeutic agents or radiotherapy to stimulate the release of endogenous antigens from tumors, thereby eliciting systemic and persistent immune activation. Recently, a bioinspired ISV strategy has attracted tremendous attention due to its features such as an immune adjuvant effect and genetic plasticity. M13 bacteriophages are natural nanomaterials with intrinsic immunogenicity, genetic flexibility, and cost-effectiveness for large-scale production, demonstrating the potential for application in cancer vaccines. In this study, we propose an ISV based on the engineered M13 bacteriophage targeting CD40 (M13CD40) for dendritic cell (DC)-targeted immune stimulation, named H-GM-M13CD40. We induce immunogenic cell death and release tumor antigens through local delivery of (S)-10-hydroxycamptothecin (HCPT), followed by intratumoral injection of granulocyte-macrophage colony stimulating factor (GM-CSF) and M13CD40 to enhance DC recruitment and activation. We demonstrate that this ISV strategy can result in significant accumulation and activation of DCs at the tumor site, reversing the immunosuppressive tumor microenvironment. In addition, H-GM-M13CD40 can synergize with the PD-1 blockade and induce abscopal effects in cold tumor models. Overall, our study verifies the immunogenicity of the engineered M13CD40 bacteriophage and provides a proof of concept that the engineered M13CD40 phage can function as an adjuvant for ISVs.

Construction of lymph nodes-targeting tumor vaccines by using the principle of DNA base complementary pairing to enhance anti-tumor cellular immune response

Tumor vaccines, a crucial immunotherapy, have gained growing interest because of their unique capability to initiate precise anti-tumor immune responses and establish enduring immune memory. Injected tumor vaccines passively diffuse to the adjacent draining lymph nodes, where the residing antigen-presenting cells capture and present tumor antigens to T cells. This process represents the initial phase of the immune response to the tumor vaccines and constitutes a pivotal determinant of their effectiveness. Nevertheless, the granularity paradox, arising from the different requirements between the passive targeting delivery of tumor vaccines to lymph nodes and the uptake by antigen-presenting cells, diminishes the efficacy of lymph node-targeting tumor vaccines. This study addressed this challenge by employing a vaccine formulation with a tunable, controlled particle size. Manganese dioxide (MnO2) nanoparticles were synthesized, loaded with ovalbumin (OVA), and modified with A50 or T20 DNA single strands to obtain MnO2/OVA/A50 and MnO2/OVA/T20, respectively. Administering the vaccines sequentially, upon reaching the lymph nodes, the two vaccines converge and simultaneously aggregate into MnO2/OVA/A50-T20 particles through base pairing. This process enhances both vaccine uptake and antigen delivery. In vitro and in vivo studies demonstrated that, the combined vaccine, comprising MnO2/OVA/A50 and MnO2/OVA/T20, exhibited robust immunization effects and remarkable anti-tumor efficacy in the melanoma animal models. The strategy of controlling tumor vaccine size and consequently improving tumor antigen presentation efficiency and vaccine efficacy via the DNA base-pairing principle, provides novel concepts for the development of efficient tumor vaccines.

Nanoparticles Targeting Lymph Nodes for Cancer Immunotherapy: Strategies and Influencing Factors

Immunotherapy has emerged as a potent strategy in cancer treatment, with many approved drugs and modalities in the development stages. Despite its promise, immunotherapy is not without its limitations, including side effects and suboptimal efficacy. Using nanoparticles (NPs) as delivery vehicles to target immunotherapy to lymph nodes (LNs) can improve the efficacy of immunotherapy drugs and reduce side effects in patients. In this context, this paper reviews the development of LN-targeted immunotherapeutic NP strategies, the mechanisms of NP transport during LN targeting, and their related biosafety risks. NP targeting of LNs involves either passive targeting, influenced by NP physical properties, or active targeting, facilitated by affinity ligands on NP surfaces, while alternative methods, such as intranodal injection and high endothelial venule (HEV) targeting, have uncertain clinical applicability and require further research and validation. LN targeting of NPs for immunotherapy can reduce side effects and increase biocompatibility, but risks such as toxicity, organ accumulation, and oxidative stress remain, although strategies such as biodegradable biomacromolecules, polyethylene glycol (PEG) coating, and impurity addition can mitigate these risks. Additionally, this work concludes with a future-oriented discussion, offering critical insights into the field.

Nanomedicines for an Enhanced Immunogenic Cell Death-Based In Situ Cancer Vaccination Response

Cancer vaccines have shown tremendous potential in preventing and treating cancer by providing immunogenic antigens to initiate specific tumor immune responses. An in situ vaccine prepared from an autologous tumor can mobilize a patient's own tumor cell lysate as a reservoir of specific antigens, thus triggering a broad immune response and diverse antitumor immunity in an individually tailored manner. Its efficacy is much better than that of conventional vaccines with a limited number of epitopes. Several conventional therapies, including radiotherapy (RT), chemotherapeutics, photodynamic therapy (PDT), and photothermal therapy (PTT) can activate an anticancer in situ vaccine response by inducing immunogenic cell death (ICD), triggering the exposure of tumor-associated antigens (TAAs), cancerous testis antigens, neoantigens, and danger-associated molecular patterns (DAMPs) with low cost. However, the immunogenicity of dying tumor cells is low, making released antigens and DAMPs insufficient to initiate a robust immune response against malignant cancer. Moreover, the immunosuppressive tumor microenvironment (TME) severely hinders the infiltration and sensitization of effector immune cells, causing tolerogenic immunological effects.Herein, we mainly focus on the research in developing nanoplatforms to surmount the major challenges met by ICD-based in situ vaccines. We first summarized a variety of nanotechnologies that enable enhanced immunogenicity of dying cancer cells by enhancing antigenicity and adjuvanticity. The robust antigenicity was obtained via regulating the tumor cells death mode or the dying state to amplify the recognition of tumor debris by professional antigen-presenting cells (APCs). The adjuvanticity was potentiated by raising the level or intensifying the activity of endogenous adjuvants or promoting the intelligent delivery of exogenous immunostimulants to activate immune cell recruitment and promote antigen presentation. Additionally, versatile approaches to reverse immunosuppressive TME to boost the in situ tumor vaccination response are also highlighted in detail. On one hand, by modulating the cell metabolism in TME, the expansion and activity of effector versus immunosuppressive cells can be optimized to improve the efficiency of in situ vaccines. On the other hand, regulating cellular components in TME, such as reversing adverse immune cell phenotypes or inhibiting the activity of interstitial cells, can also significantly enhance the ICD-based antitumor immunotherapy effect. Finally, our viewpoint on the future challenges and opportunities in this hopeful area is presented. We expect that this Account can offer much more insight into the design, planning, and development of cutting-edge in situ tumor vaccine platforms, promoting more attention and academic-industry collaborations, accelerating the advanced progress of in situ tumor vaccine-based immunotherapy in the clinic.

Self-Adjuvanting Polyguanidine Nanovaccines for Cancer Immunotherapy

Tapping into the innate immune system's power, nanovaccines can induce tumor-specific immune responses, which is a promising strategy in cancer immunotherapy. However, traditional vaccine design, requiring simultaneous loading of antigens and adjuvants, is complex and poses challenges for mass production. Here, we developed a tumor nanovaccine platform that integrates adjuvant functions into the delivery vehicle, using branched polyguanidine (PolyGu) nanovaccines. These nanovaccines were produced by modifying polyethylenimine (PEI) with various guanidine groups, transforming PEI's cytotoxicity into innate immune activation. The PolyGu nanovaccines based on poly(phenyl biguanidine ) (Poly-PBG) effectively stimulated dendritic cells, promoted their maturation via the TLR4 and NLRP3 pathways, and displayed robust in vivo immune activity. They significantly inhibited tumor growth and extended mouse survival. The PolyGu also showed promise for constructing more potent mRNA-based nanovaccines, offering a platform for personalized cancer vaccine. This work advances cancer immunotherapy toward potential clinical application by introducing a paradigm for developing self-adjuvanting nanovaccines.

Zwitterionic Injectable Hydrogel-Combined Chemo- and Immunotherapy Medicated by Monomolecular Micelles to Effectively Prevent the Recurrence of Tumor Post Operation

Surgical resection remains the most common method of tumor treatment; however, the high recurrence and metastasis after surgery need to be solved urgently. Herein, we report an injectable zwitterionic hydrogel based on "thiol-ene" click chemistry containing doxorubicin (DOX) and a macrophage membrane (MM)-coated 1-methyl-tryptophan (1-MT)-loaded polyamide-amine dendrimer (P-DOX/1MT) for preventing the postoperative recurrence of tumors. The results indicated that P-DOX/1MT@MM exhibited enhanced recognition and uptake of the dendrimer by tumor cells and induced the immunogenic cell death. In the mice tumor model, the P-DOX/1MT@MM-Gel exhibited high therapeutic efficiency, which could significantly reduce the recurrence of the tumor, including suppressing tumor growth, promoting dendritic cell maturation, and increasing tumor-infiltrating cytotoxic T lymphocytes. The mechanism analysis revealed that the hydrogel greatly reduces the side effects to normal tissues and significantly improves its therapeutic effect. 1MT in the hydrogel is released more rapidly, improving the tumor suppressor microenvironment and increasing the tumor cell sensitivity to DOX. Then, the DOX in the P-DOX/1MT@MM effectively eliminatedo the residual tumor cells and exerted enhanced toxicity. In conclusion, this novel injectable hydrogel that combines chemotherapy and immunotherapy has the property of sequential drug release and is a promising strategy for preventing the postoperative recurrence of tumors.

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.

Advances in Cancer Vaccine Research

The use of cancer vaccines is considered a promising therapeutic strategy in clinical oncology, which is achieved by stimulating antitumor immunity with tumor antigens delivered in the form of cells, peptides, viruses, and nucleic acids. The ideal cancer vaccine has many advantages, including low toxicity, specificity, and induction of persistent immune memory to overcome tumor heterogeneity and reverse the immunosuppressive microenvironment. Many therapeutic vaccines have entered clinical trials for a variety of cancers, including melanoma, breast cancer, lung cancer, and others. However, many challenges, including single antigen targeting, weak immunogenicity, off-target effects, and impaired immune response, have hindered their broad clinical translation. In this review, we introduce the principle of action, components (including antigens and adjuvants), and classification (according to applicable objects and preparation methods) of cancer vaccines, summarize the delivery methods of cancer vaccines, and review the clinical and theoretical research progress of cancer vaccines. We also present new insights into cancer vaccine technologies, platforms, and applications as well as an understanding of potential next-generation preventive and therapeutic vaccine technologies, providing a broader perspective for future vaccine design.

Biomembrane nanostructures: Multifunctional platform to enhance tumor chemoimmunotherapy via effective drug delivery

Chemotherapeutic drugs have been found to activate the immune response against tumors by inducing immunogenic cell death, in addition to their direct cytotoxic effects toward tumors, therefore broadening the application of chemotherapy in tumor immunotherapy. The combination of other therapeutic strategies, such as phototherapy or radiotherapy, could further strengthen the therapeutic effects of immunotherapy. Nanostructures can facilitate multimodal tumor therapy by integrating various active agents and combining multiple types of therapeutics in a single nanostructure. Biomembrane nanostructures (e.g., exosomes and cell membrane-derived nanostructures), characterized by superior biocompatibility, intrinsic targeting ability, intelligent responsiveness and immune-modulating properties, could realize superior chemoimmunotherapy and represent next-generation nanostructures for tumor immunotherapy. This review summarizes recent advances in biomembrane nanostructures in tumor chemoimmunotherapy and highlights different types of engineering approaches and therapeutic mechanisms. A series of engineering strategies for combining different biomembrane nanostructures, including liposomes, exosomes, cell membranes and bacterial membranes, are summarized. The combination strategy can greatly enhance the targeting, intelligence and functionality of biomembrane nanostructures for chemoimmunotherapy, thereby serving as a stronger tumor therapeutic method. The challenges associated with the clinical translation of biomembrane nanostructures for chemoimmunotherapy and their future perspectives are also discussed.