Sheddable Prodrug Vesicles Combating Adaptive Immune Resistance for Improved Photodynamic Immunotherapy of Cancer.

Photodynamic therapy (PDT) capable of eliciting a robust antitumor immune response has been considered an attractive therapeutic approach. However, adaptive immune resistance in PDT underlines the need to develop alternative strategies. The exquisite power of checkpoint blockade can be harnessed to reinvigorate antitumor immune response. Here, we demonstrate that PDT-triggered adaptive immune resistance can be overcome by inactivating indoleamine 2,3-dioxygenase 1 (IDO-1). We rationally designed a tumor-microenvironment-sheddable prodrug vesicle by integrating a PEGylated photosensitizer (PS) and a reduction-sensitive prodrug of IDO-1 inhibitor. The prodrug vesicles were inert during the blood circulation, whereas they specifically accumulated and penetrated at the tumor site through matrix metalloproteinase-2 (MMP-2)-mediated cleavage of the PEG corona to achieve fluorescence-imaging-guided photodynamic therapy (PDT). Compared to PDT alone, the prodrug-vesicle-mediated combination immunotherapy provoked augmented antitumor immunity to eradicate the tumor in both CT26 colorectal and 4T1 breast immunocompetent mouse models. The prodrug vesicles dramatically suppressed tumor reoccurrence, particularly in overexpressing IDO-1 tumor models, i.e., CT26. This study might provide novel insight into the development of new nanomedicine to enhance the efficacy of photodynamic immunotherapy while addressing the adaptive immune resistance.

Molecular Imaging for Cancer Immunotherapy: Seeing Is Believing.

The importance of the immune system in cancer therapy has been reaffirmed by the success of the immune checkpoint blockade. The complex tumor microenvironment and its interaction with the immune system, however, remain mysteries. Molecular imaging may shed light on fundamental aspects of the immune response to elucidate the mechanism of cancer immunotherapy. In this review, we discuss various imaging approaches that offer in-depth insight into the tumor microenvironment, checkpoint blockade therapy, and T cell-mediated antitumor immune responses. Recent advances in the molecular imaging modalities, including magnetic resonance imaging (MRI), positron electron tomography (PET), and optical imaging (e.g., fluorescence and intravital imaging) for in situ tracking of the immune response, are discussed. It is envisaged that the integration of imaging with immunotherapy may broaden our understanding to predict a particular antitumor immune response.

Non-viral gene delivery for cancer immunotherapy.

Recent decades have witnessed the revolutionary development of cancer immunotherapies, which boost cancer-specific immune responses for long-term tumor regression. However, immunotherapy still has limitations, including off-target side effects, long processing times and limited patient responses. These disadvantages of current immunotherapy are being addressed by improving our understanding of the immune system, as well as by establishing combinational approaches. Advanced biomaterials and gene delivery systems overcome some of these delivery issues, harnessing adverse effects and amplifying immunomodulatory effects, and are superior to standard formulations with respect to eliciting antitumor immunity. Nucleic acid-based nanostructures have diverse functions, ranging from gene expression and gene regulation to pro-inflammatory effects, as well as the ability to specifically bind different molecules. A brief overview is provided of the recent advances in the non-viral gene delivery methods that are being used to activate cancer-specific immune responses. Furthermore, the tumor microenvironment-responsive synergistic strategies that modulate the immune response by targeting various signaling pathways are discussed. Nanoparticle-based non-viral gene delivery strategies have great potential to be implemented in the clinic for cancer immunotherapy.

The Transition from Metal-Based to Metal-Free Contrast Agents for T1 Magnetic Resonance Imaging Enhancement.

Magnetic resonance imaging (MRI) has received significant attention as the noninvasive diagnostic technique for complex diseases. Image-guided therapeutic strategy for diseases such as cancer has also been at the front line of biomedical research, thanks to the innovative MRI, enhanced by the prior delivery of contrast agents (CAs) into patients' bodies through injection. These CAs have contributed a great deal to the clinical utility of MRI but have been based on metal-containing compounds such as gadolinium, manganese, and iron oxide. Some of these CAs have led to cytotoxicities such as the incurable Nephrogenic Systemic Fibrosis (NSF), resulting in their removal from the market. On the other hand, CAs based on organic nitroxide radicals, by virtue of their structural composition, are metal free and without the aforementioned drawbacks. They also have improved biocompatibility, ease of functionalization, and long blood circulation times, and have been proven to offer tissue contrast enhancement with longitudinal relaxivities comparable with those for the metal-containing CAs. Thus, this Review highlights the recent progress in metal-based CAs and their shortcomings. In addition, the remarkable goals achieved by the organic nitroxide radical CAs in the enhancement of MR images have also been discussed extensively. The focal point of this Review is to emphasize or demonstrate the crucial need for transition into the use of organic nitroxide radicals-metal-free CAs-as against the metal-containing CAs, with the aim of achieving safer application of MRI for early disease diagnosis and image-guided therapy.

Overview of recent advances in liposomal nanoparticle-based cancer immunotherapy.

The clinical performance of conventional cancer therapy approaches (surgery, radiotherapy, and chemotherapy) has been challenged by tumor metastasis and recurrence that is mainly responsible for cancer-caused mortalities. The cancer immunotherapy is being emerged nowadays as a promising therapeutic modality in order to achieve a highly efficient therapeutic performance while circumventing tumor metastasis and relapse. Liposomal nanoparticles (NPs) may serve as an ideal platform for systemic delivery of the immune modulators. In this review, we summarize the cutting-edge progresses in liposomal NPs for cancer immunotherapy, with focus on dendritic cells, T cells, tumor cells, natural killer cells, and macrophages. The review highlights the major challenges and provides a perspective regarding the clinical translation of liposomal nanoparticle-based immunotherapy.

Porous Gold Nanoshells on Functional NH2 -MOFs: Facile Synthesis and Designable Platforms for Cancer Multiple Therapy.

AuroShell nanoparticles (sealed gold nanoshell on silica) are the only inorganic materials that are approved for clinical trial for photothermal ablation of solid tumors. Based on that, porous gold nanoshell structures are thus critical for cancer multiple theranostics in the future owing to their inherent cargo-loading ability. Nevertheless, adjusting the diverse experimental parameters of the reported procedures to obtain porous gold nanoshell structures is challenging. Herein, a series of amino-functionalized porous metal-organic frameworks (NH2 -MOFs) nanoparticles are uncovered as superior templates for porous gold nanoshell deposition (NH2 -MOFs@Aushell ) by means of a more facile and general one-step method, which combines the enriched functionalities of NH2 -MOFs with those of porous gold nanoshells. Moreover, in order to illustrate the promising applications of this method in biomedicine, platinum nanozymes-encapsulated NH2 -MOFs are further designed with porous gold nanoshell coating and photosensitizer chlorin e6 (Ce6)-loaded nanoparticles with continuous O2 -evolving ability (Pt@UiO-66-NH2 @Aushell -Ce6). The combination of photodynamic and photothermal therapy is then carried out both in vitro and in vivo, achieving excellent synergistic therapeutic outcomes. Therefore, this work not only presents a facile strategy to fabricate functionalized porous gold nanoshell structures, but also illustrates an excellent synergistic tumor therapy strategy.

PROTAC Prodrug-Integrated Nanosensitizer for Potentiating Radiation Therapy of Cancer.

Radiation therapy (RT) is one of the primary options for clinical cancer therapy, in particular advanced head and neck squamous cell carcinoma (HNSCC). Herein, the crucial role of bromodomain-containing protein 4 (BRD4)-RAD51 associated protein 1 (RAD51AP1) axis in sensitizing RT of HNSCC is revealed. A versatile nanosensitizer (RPB7H) is thus innovatively engineered by integrating a PROteolysis TArgeting Chimeras (PROTAC) prodrug (BPA771) and hafnium dioxide (HfO2) nanoparticles to downregulate BRD4-RAD51AP1 pathway and sensitize HNSCC tumor to RT. Upon intravenous administration, the RPB7H nanoparticles selectively accumulate at the tumor tissue and internalize into tumor cells by recognizing neuropilin-1 overexpressed in the tumor mass. HfO2 nanoparticles enhance RT effectiveness by amplifying X-ray deposition, intensifying DNA damage, and boosting oxidative stress. Meanwhile, BPA771 can be activated by RT-induced H2O2 secretion to degrade BRD4 and inactivate RAD51AP1, thus impeding RT-induced DNA damage repair. This versatile nanosensitizer, combined with X-ray irradiation, effectively regresses HNSCC tumor growth in a mouse model. The findings introduce a PROTAC prodrug-based radiosensitization strategy by targeting the BRD4-RAD51AP1 axis, may offer a promising avenue to augment RT and more effective HNSCC therapy.

Facile synthesis of gold nanocages with silver nanocubes templates dual metal effects enabled SERS imaging and catalytic reduction.

Silver (Ag) nanomaterials featuring a cubic shape particularly represent supreme class of advance nanomaterials. This work explored a new precursor and its effect on morphological features of silver (Ag) nanocubes (NCs) serving as sacrificial templates for facile synthesis of gold NCs. The AgNCs were initially prepared utilizing sodium thiosulphate (Na2S2O3) as relatively stable S2- producing species along with a soft etchant source KCl. The effects of different potassium halides were evaluated to grasp control over seed mediated growth of Ag nanocubes. Taking the advantages of dual metallic properties, Ag@4MBA@AuNCs nanostructure was synthesized using 4-mercaptobenzoic acid (4MBA) as a Raman reporter molecule. This nanostructure showed 1010-times enhancement in surface enhanced Raman scattering (SERS) signal, leading to a highly sensitive imaging probe for the detection of even three breast cancer cells (MCF-7 cells) in vitro. Subsequently, the oxidative nanopeeling well accompanied by incorporation of Au/Ag alloy nanoparticles on AuNCs corona assembly was achieved, which facilitated the catalytic reduction of toxic nitrophenol to eco-friendly aminophenol. Such sophisticated and engineered nanoassemblies possess broad applications in bioanalysis.

Seed-Based System for Cost-Effective Production of Vaccine Against Chronic Respiratory Disease in Chickens.

The production of vaccines in plant cells, termed plant-made pharmaceuticals or molecular farming, is a promising technology for scalable production. Compared to mammalian cell lines, like Chinese Hamster Ovary (CHO) or bacterial cells, plants can be grown with less cost on a large scale to make vaccines antigens and therapeutics affordable and accessible worldwide. An innovative application of this alternative system is the production of vaccines in edible tissues that can be consumed orally to deliver protein antigen without any further processing. In this project, we report stable expression of amino acid sequences corresponding to the TM-1 gene of Mycoplasma gallisepticum as a candidate vaccine antigen against Chronic Respiratory Disease (CRD) in chickens using wheat seed's tissues as a production host. Molecular and immunoblotting analysis confirmed the ubiquitous expression of a recombinant 41.8-kDa protein with an expression level of 1.03 mg/g dry weight in the endosperm tissues. When orally delivered, the plant-made vaccine was effective in terms of developing antibody response in animal model i.e., chicken without any detectable weight loss. Two doses of orally delivered plant-made TM-1 vaccine candidate elicited the immune response and protective effect against MG virus challenge at the level comparable to commercially available inactivated vaccine against CRD. Our study demonstrates that plant-made vaccines are not only safe but also scalable and cost-effective with prolonged stability at room temperature.

Self-Immolated Nanoadjuvant for In Situ Vaccination Immunotherapy of Colorectal Cancer.

Vaccination immunotherapy has revolutionized cancer treatment modalities. Although the immunomodulatory adjuvant generally employs for potentiating vaccine response, systemic administration may drive immune-related side effects, even immune tolerance. Therefore, tunable immunoadjuvants are highly desirable to simultaneously stimulate the immune response and mitigate systemic toxicity. Self-immolated nanoadjuvants are herein reported to potentiate vaccination immunotherapy of cancer. The nanoadjuvants are engineered by co-assembling an intracellular acidity-ionizable polymeric agonist of toll-like receptor 7/8 resiquimod (R848) and polymeric photosensitizer pyropheophorbide a (PPa). The resultant nanoadjuvants specifically accumulate at the tumor site via passive targeting and are dissociated in the acidic endosome versicles to activate PPa via protonation of the polymer backbone. Upon 671 nm laser irradiation, PPa performed photodynamic therapy to induce immunogenic cell death of tumor cells and subsequently releases R848 in a customized manner, which synergistically activates dendritic cells (DCs), promotes antigen cross-presentation, and eventually recruits cytotoxic T lymphocytes for tumor regression. Furthermore, the synergistic in situ vaccination immunotherapy with immune checkpoint blockade induce sustained immunological memory to suppress tumor recurrence in the rechallenged colorectal tumor model.

Acid-Ionizable Iron Nanoadjuvant Augments STING Activation for Personalized Vaccination Immunotherapy of Cancer.

The critical challenge for cancer vaccine-induced T-cell immunity is the sustained activation of antigen cross-presentation in antigen-presenting cells (APCs) with innate immune stimulation. In this study, it is first discovered that the clinically used magnetic contrast agents, iron oxide nanoparticles (IONPs), markedly augment the type-I interferon (IFN-I) production profile of the stimulator of interferon genes (STING) agonist MSA-2 and achieve a 16-fold dosage-sparing effect in the human STING haplotype. Acid-ionizable copolymers are coassembled with IONPs and MSA-2 into iron nanoadjuvants to concentrate STING activation in the draining lymph nodes. The top candidate iron nanoadjuvant (PEIM) efficiently delivers the model antigen ovalbumin (OVA) to CD169+ APCs and facilitates antigen cross-presentation to elicit a 55-fold greater frequency of antigen-specific CD8+ cytotoxic T-lymphocyte response than soluble antigen. PEIM@OVA nanovaccine immunization induces potent and durable antitumor immunity to prevent tumor lung metastasis and eliminate established tumors. Moreover, PEIM nanoadjuvant is applicable to deliver autologous tumor antigen and synergizes with immune checkpoint blockade therapy for prevention of postoperative tumor recurrence and distant metastasis in B16-OVA melanoma and MC38 colorectal tumor models. The acid-ionizable iron nanoadjuvant offers a generalizable and readily translatable strategy to augment STING cascade activation and antigen cross-presentation for personalized cancer vaccination immunotherapy.

Dual-targeting prodrug nanotheranostics for NIR-â ¡ fluorescence imaging-guided photo-immunotherapy of glioblastoma.

Glioblastoma (GBM) therapy is severely impaired by the blood-brain barrier (BBB) and invasive tumor growth in the central nervous system. To improve GBM therapy, we herein presented a dual-targeting nanotheranostic for second near-infrared (NIR-II) fluorescence imaging-guided photo-immunotherapy. Firstly, a NIR-Ⅱ fluorophore MRP bearing donor-acceptor-donor (D-A-D) backbone was synthesized. Then, the prodrug nanotheranostics were prepared by self-assembling MRP with a prodrug of JQ1 (JPC) and T7 ligand-modified PEG5k-DSPE. T7 can cross the BBB for tumor-targeted delivery of JPC and MRP. JQ1 could be restored from JPC at the tumor site for suppressing interferon gamma-inducible programmed death ligand 1 expression in the tumor cells. MRP could generate NIR-II fluorescence to navigate 808 nm laser, induce a photothermal effect to trigger in-situ antigen release at the tumor site, and ultimately elicit antitumor immunogenicity. Photo-immunotherapy with JPC and MRP dual-loaded nanoparticles remarkably inhibited GBM tumor growth in vivo. The dual-targeting nanotheranostic might represent a novel nanoplatform for precise photo-immunotherapy of GBM.

Nanobiomaterial-based vaccination immunotherapy of cancer.

Cancer immunotherapies including cancer vaccines, immune checkpoint blockade or chimeric antigen receptor T cells have been exploited as the attractive treatment modalities in recent years. Among these approaches, cancer vaccines that designed to deliver tumor antigens and adjuvants to activate the antigen presenting cells (APCs) and induce antitumor immune responses, have shown significant efficacy in inhibiting tumor growth, preventing tumor relapse and metastasis. Despite the potential of cancer vaccination strategies, the therapeutic outcomes in preclinical trials are failed to promote their clinical translation, which is in part due to their inefficient vaccination cascade of five critical steps: antigen identification, antigen encapsulation, antigen delivery, antigen release and antigen presentation to T cells. In recent years, it has been demonstrated that various nanobiomaterials hold great potential to enhance cancer vaccination cascade and improve their antitumor performance and reduce the off-target effect. We summarize the cutting-edge advances of nanobiomaterials-based vaccination immunotherapy of cancer in this review. The various cancer nanovaccines including antigen peptide/adjuvant-based nanovaccines, nucleic acid-based nanovaccines as well as biomimetic nanobiomaterials-based nanovaccines are discussed in detail. We also provide some challenges and perspectives associated with the clinical translation of cancer nanovaccines.

Acidity-Activatable Dynamic Nanoparticles Boosting Ferroptotic Cell Death for Immunotherapy of Cancer.

Immunotherapy shows promising therapeutic potential for long-term tumor regression. However, current cancer immunotherapy displays a low response rate due to insufficient immunogenicity of the tumor cells. To address these challenges, herein, intracellular-acidity-activatable dynamic nanoparticles for eliciting immunogenicity by inducing ferroptosis of the tumor cells are engineered. The nanoparticles are engineered by integrating an ionizable block copolymer and acid-liable phenylboronate ester (PBE) dynamic covalent bonds for tumor-specific delivery of the ferroptosis inducer, a glutathione peroxidase 4 inhibitor RSL-3. The nanoparticles can stably encapsulate RSL-3 inside the hydrophobic core via π-π stacking interaction with the PBE groups at neutral pH (pH = 7.4), while releasing the payload in the endocytic vesicles (pH = 5.8-6.2) by acidity-triggered cleavage of the PBE dynamic covalent bonds. Furthermore, the nanoparticles can perform acid-activatable photodynamic therapy by protonation of the ionizable core, and significantly recruit tumor-infiltrating T lymphocytes for interferon gamma secretion, and thus sensitize the tumor cells to RSL-3-inducible ferroptosis. The combination of nanoparticle-induced ferroptosis and blockade of programmed death ligand 1 efficiently inhibits growth of B16-F10 melanoma tumor and lung metastasis of 4T1 breast tumors, suggesting the promising potential of ferroptosis induction for promoting cancer immunotherapy.

From Design to Clinic: Engineered Nanobiomaterials for Immune Normalization Therapy of Cancer.

The tumor immune microenvironment (TIME) is comprised of a complex milieu that contributes to stunting antitumor immune responses by restricting T cells to accumulate in the vicinity of the tumor. Nanomedicine-based strategies are being proposed as a salvage effort to reinvigorate antitumor immunity. Various strategies, however, often fail to unleash the antitumor immune response because of the paucity of appropriate therapeutic targets in the complex TIME, invigorating a fervor of investigation into mechanisms underlying the TIME to resist nanomedicines. In this review article, effective nano/biomaterial-based delivery and TIME normalization approaches that promote T cell-mediated antitumor immune response will be discussed, with a focus on emerging preclinical and clinical strategies for immune normalization. Based on currently available evidence, it seems as if the ultimate success of cancer immunotherapy and nanomedicine hinges on the capacity to normalize the TIME. Here, how nanomedicines target immunosuppressive cells and signaling pathways to broaden the impact of cancer immunotherapy are explored. Acquisition of the urgently needed knowledge of nanomedicine-mediated immune normalization will guide researchers and scientists towards clinical applications of cancer immunotherapy.

Regulating Glucose Metabolism with Prodrug Nanoparticles for Promoting Photoimmunotherapy of Pancreatic Cancer.

The low immunogenicity, insufficient infiltration of T lymphocytes, and dismal response to immune checkpoint blockade therapy pose major difficulties in immunotherapy of pancreatic cancer. Photoimmunotherapy by photodynamic therapy (PDT) can induce an antitumor immune response by triggering immunogenic cell death in the tumor cells. Notwithstanding, PDT-driven oxygen consumption and microvascular damage can further aggravate hypoxia to exaggerates glycolysis, leading to lactate accumulation and immunosuppressive tumor microenvironment. Herein, a supramolecular prodrug nanoplatform codelivering a photosensitizer and a prodrug of bromodomain-containing protein 4 inhibitor (BRD4i) JQ1 for combinatory photoimmunotherapy of pancreatic cancer are demonstrated. The nanoparticles are fabricated by host-guest complexation between cyclodextrin-grafted hyaluronic acid (HA-CD) and adamantine-conjugated heterodimers of pyropheophorbide a (PPa) and JQ1, respectively. HA can achieve active tumor targeting by recognizing highly expressed CD44 on the surface of pancreatic tumors. PPa-mediated PDT can enhance the immunogenicity of the tumor cells and promote intratumoral infiltration of the cytotoxic T lymphocytes. Meanwhile, JQ1 combats PDT-mediated immune evasion through inhibiting expression of c-Myc and PD-L1, which are key regulators of tumor glycolysis and immune evasion. Collectively, this study presents a novel strategy to enhance photoimmunotherapy of the pancreatic cancer by provoking T cells activation and overcoming adaptive immune resistance.

Engineering Stimuli-Activatable Boolean Logic Prodrug Nanoparticles for Combination Cancer Immunotherapy.

Prodrug nanoparticles that codeliver the immune modulators to the tumor site are highly recommendable for cancer immunotherapy yet remain challenging. However, effective stimuli-responsive strategies that exploit the endogenous hallmarks of the tumor have paved the way for cancer immunotherapy. For the first time, the development of the Boolean logic prodrug nanoparticles (BLPNs) for tumor-targeted codelivery of immune modulators (e.g., immune activator and immune inhibitor) and combination immunotherapy is reported herein. A library of stimuli-activatable BLPNs is fabricated yielding YES/AND logic outputs by adjusting the input combinations, including extracellular matrix metalloproteins 2/9 (MMP-2/9), intracellular acidity (pH = 5.0-6.0), and reduction (glutathione) in the tumor microenvironment. Tunable and selective control over BLPNs dissociation and prodrug activation is achieved by specifying the connectivity of orthogonal stimuli-labile spacers while exploiting the endogenous signals at the tumor sites. The tumor-specific distribution of the BLPNs and stimuli-activation of the immune modulators for highly efficient cancer immunotherapy are further demonstrated. The results reported in this study may open a new avenue for tumor-specific delivery of immune therapeutics and precise cancer immunotherapy.

Supramolecular Prodrug Nanovectors for Active Tumor Targeting and Combination Immunotherapy of Colorectal Cancer.

Immunotherapy aiming to harness the exquisite power of the immune system has emerged as a crucial part of clinical cancer management. However, only a subset of cancer patients responds to current immunotherapy because of low immunogenicity of the tumor cells and immunosuppressive tumor microenvironment. Herein, host-guest prodrug nanovectors are reported for active tumor targeting and combating immune tolerance in tumors. The prodrug nanovectors are designed by integrating hyaluronic acid (HA) and reduction-labile heterodimer of Pheophorbide A (PPa) and NLG919 into the supramolecular nanocomplexes, where PPa and NLG919 act as a photosensitizer and potent inhibitor of indoleamine 2,3-dioxygenase 1 (IDO-1), respectively. Meanwhile, HA is employed to achieve active tumor targeting by recognizing CD44 overexpressed on the surface of tumor cell membranes. Near infrared (NIR) laser irradiation triggers the release of reactive oxygen species to provoke antitumor immunogenicity and intratumoral infiltration of cytotoxic T lymphocytes (CTLs). Meanwhile, the immunosuppressive tumor microenvironment (ITM) is reversed by NLG919-mediated IDO-1 inhibition. Combination of photodynamic immunotherapy and IDO-1 blockade efficiently eradicates CT26 colorectal tumors in the immunocompetent mice. The host-guest nanoplatform capable of eliciting effective antitumor immunity by inactivating inhibitory immune response can be applied to other immune modulators for improved cancer immunotherapy.