Elimination of established tumors with nanodisc-based combination chemoimmunotherapy

Combination Cancer Immunotherapy of Nanoparticle-Based Immunogenic Cell Death Inducers and Immune Checkpoint Inhibitors

Cancer immunotherapy is a promising treatment strategy that aims to strengthen immune responses against cancer. However, the low immunogenicity of tumor cells and inhibition of effector T cells in the tumor immunosuppressive microenvironment remain two major challenges. Immunogenic cell death (ICD) inducers not only directly kill cancer cells but also increase the tumor immunogenicity and induce antitumor immune responses. Immune checkpoint inhibitors can alleviate the inhibition of immune cells. Significantly, the combination of ICD inducers and immune checkpoint inhibitors elicits a remarkable antitumor effect. Nanoparticles confer the ability to modulate systemic biodistribution and achieve targeted accumulation of administered therapeutic agents, thereby facilitating the clinical translation of immunotherapies based on ICD inducers in a safe and effective manner. In this review, we summarize the nanoparticle-based chemical and physical cues that induce effective tumor ICD and elicit an antitumor immune response. In particular, combination of ICD inducers with immune checkpoint inhibitors can further reverse immunosuppression and prevent tumor metastasis and recurrence. An overview of the future challenges and prospects is also provided.

A combinational chemo-immune therapy using an enzyme-sensitive nanoplatform for dual-drug delivery to specific sites by cascade targeting

Nanoparticle-based drug delivery faces challenges from the imprecise targeted delivery and the low bioavailability of drugs due to complex biological barriers. Here, we designed cascade-targeting, dual drug–loaded, core-shell nanoparticles (DLTPT) consisting of CD44-targeting hyaluronic acid shells decorated with doxorubicin (HA-DOX) and mitochondria-targeting triphenylphosphonium derivative nanoparticle cores loaded with lonidamine (LND) dimers (LTPT). DLTPT displayed prolonged blood circulation time and efficiently accumulated at the tumor site due to the tumor-homing effect and negatively charged hyaluronic acid. Subsequently, the HA-DOX shell was degraded by extracellular hyaluronidase, resulting in decreased particle size and negative-to-positive charge reversal, which would increase tumor penetration and internalization. The degradation of HA-DOX further accelerated the release of DOX and exposed the positively charged LTPT core for rapid endosomal escape and mitochondria-targeted delivery of LND. Notably, when DLTPT was used in combination with anti–PD-L1, the tumor growth was inhibited, which induced immune response against tumor metastasis.

Nanotechnology-based platforms to improve immune checkpoint blockade efficacy in cancer therapy

In recent years, cancer immunotherapy has evolved as an exciting novel strategy for researchers and clinicians worldwide. Immunotherapeutic agents such as immune checkpoint blockers have changed the standard-of-care treatment provided for many tumors. Unfortunately, only a small proportion of patients respond effectively to these checkpoint inhibitors. Moreover, the immunosuppressive pathways for cancer are probably too complicated to achieve optimal outcome with immune checkpoint inhibitors alone. Combining current therapeutic options and immunotherapy-based approaches is being explored as an effective strategy to treat cancer. The use of nanotechnology-based platforms for delivery of immunotherapeutic agents or combination therapy could offer a major advantage over conventional anticancer treatment options. This review highlights the potential role of different nanotechnology-based strategies in improving the efficacy of immune checkpoint blockade therapy.

Effect of apoA-I PEGylation on the Biological Fate of Biomimetic High-Density Lipoproteins

Biomimetic high-density lipoproteins (b-HDL) have in the past two decades been applied for various drug delivery applications. As b-HDL inherently have relatively long circulation half-life and high tumor accumulation, this has inspired researchers to use b-HDL to selectively deliver drugs to tumors. PEGylation of the b-HDL has been pursued to increase the circulation half-life and therapeutic efficacy even further. The b-HDL consist of lipids stabilized by a protein/peptide scaffold, and while PEGylation of the scaffold has been shown to greatly increase the circulation half-life of the scaffold, the effect of PEGylation of the lipids is much less significant. Still, it remains to be evaluated how the biological fate, including cellular uptake, biodistribution, and circulation half-life, of the b-HDL lipids is affected by PEGylation of the b-HDL scaffold. We studied this with apolipoprotein A-I (apoA-I)-based b-HDL and mono-PEGylated b-HDL (PEG b-HDL) both in vitro and in vivo. We found that PEGylation of the b-HDL scaffold only seemed to have minimal effect on the biological fate of the lipids. Both b-HDL and PEG b-HDL overall shared similar biological fates, which includes cellular uptake through the scavenger receptor class B type 1 (SR-BI) and relatively high tumor accumulation. This highlights that b-HDL are dynamic particles, and the biological fates of the b-HDL components (lipids and scaffold) can differ. A phenomenon that may also apply for other multicomponent nanoparticles.

Tumor microenvironment-activated therapeutic peptide-conjugated prodrug nanoparticles for enhanced tumor penetration and local T cell activation in the tumor microenvironment

Nanomedicine-based chemoimmunotherapy has shown a great potential for cancer therapies application in recent years. However, most nanoparticles still face a problem of low accumulation and limited penetration of chemotherapeutic drugs and immunotherapeutic drugs into solid tumors. Here, we developed a tumor microenvironment (TME)-activable therapeutic peptide-conjugated prodrug nanoparticle for enhanced tumor penetration and synergistic antitumor effects of chemotherapy and immune checkpoint blockade therapy. The prodrug nanoparticle is composed of a short D-peptide antagonist of PD-L1 (^DPPA) conjugated doxorubicin (DOX) prodrug and a PEGylated DOX prodrug, which can dissociate into small DOX nanoparticles (<30 nm) and release ^DPPA antagonist in TME. The prodrug nanoparticles could co-deliver DOX and ^DPPA antagonist by one nanocarrier and improve tumor accumulation and penetration of the prodrug nanoparticels via a transcytosis process. It is demonstrated that co-delivery of DOX and ^DPPA antagonist directly killed tumor cells, promoted the tumor-infiltrating cytotoxic T lymphocytes, reduced the tumor-infiltrating regulatory T cells, and elicited a long-term immune memory effect to prevent tumor recurrence and metastasis. This TME-activable prodrug nanoparticle holds promise as a co-delivery nanoplatform for the improved chemoimmunotherapy of solid tumors.

Phenolic immunogenic cell death nanoinducer for sensitizing tumor to PD-1 checkpoint blockade immunotherapy

A critical challenge remains in PD-1 checkpoint blockade immunotherapy is few tumor specific T cells infiltration in hypoxic tumor microenvironment (TME). Improving immunogenic cell death (ICD) associated immunogenicity can make tumor sensitive to PD-1 checkpoint blockade immunotherapy. Herein, a phenolic ICD inducer was engineered by self-assembly of the superior ICD inducer (doxorubicin, DOX), phenolic manganese dioxide nanoreactor, ferric iron and PEG-polyphenols (MDP NPs) via metal phenolic coordination. These oxygen self-supporting MDP NPs strengthen DOX based ROS-dependent cell death and their metal mediated chemodynamic effect accelerate ICD induction. Together with concomitant ICD triggered by DOX, MDP NPs successively lead to tumor-associated antigen boosting, DCs maturation and ultimately enhance tumor-specific T cells infiltration. Furthermore, MDP NPs efficiently modulated hypoxic TME for effective macrophages recruitment. This promising ICD-augment strategy efficiently improve tumor response to PD-1 checkpoint blockade immunotherapy, resulting in a significant antitumor immune response in primary tumor and a strong abscopal effect to distant tumor. Our simple and versatile phenolic inducer expands the application of chemodrugs based ICD enhancing PD-1 checkpoint blockade immunotherapy.

Fluorine assembly nanocluster breaks the shackles of immunosuppression to turn the cold tumor hot

Clinical investigations have shown that a nonimmunogenic "cold" tumor is usually accompanied by few immunopositive cells and more immunosuppressive cells in the tumor microenvironment (TME), which is still the bottleneck of immune activation. Here, a fluorine assembly nanocluster was explored to break the shackles of immunosuppression, reawaken the immune system, and turn the cold tumor "hot." Once under laser irradiation, FS@PMPt produces sufficient reactive oxygen species (ROS) to fracture the ROS-sensitive linker, thus releasing the cisplatin conjugated PMPt to penetrate into the tumors and kill the regulatory T cells (Tregs) and myeloid-derived suppressor cells (MDSCs). Meanwhile, ROS will induce potent immunogenic cell death (ICD) and further promote the accumulation of dendritic cells (DCs) and T cells, therefore not only increasing the infiltration of immunopositive cells from the outside but also reducing the immunosuppressive cells from the inside to break through the bottleneck of immune activation. The FS@PMPt nanocluster regulates the immune process in TME from negative to positive, from shallow to deep, to turn the cold tumor into a hot tumor and provoke a robust antitumor immune response.

A systematic review of the biodistribution of biomimetic high-density lipoproteins in mice

For the past two decades, biomimetic high-density lipoproteins (b-HDL) have been used for various drug delivery applications. The b-HDL mimic the endogenous HDL, and therefore possess many attractive features for drug delivery, including high biocompatibility, biodegradability, and ability to transport and deliver their cargo (e.g. drugs and/or imaging agents) to specific cells and tissues that are recognized by HDL. The b-HDL designs reported in the literature often differ in size, shape, composition, and type of incorporated cargo. However, there exists only limited insight into how the b-HDL design dictates their biodistribution. To fill this gap, we conducted a comprehensive systematic literature search of biodistribution studies using various designs of apolipoprotein A-I (apoA-I)-based b-HDL (i.e. b-HDL with apoA-I, apoA-I mutants, or apoA-I mimicking peptides). We carefully screened 679 papers (search hits) for b-HDL biodistribution studies in mice, and ended up with 24 relevant biodistribution profiles that we compared according to b-HDL design. We show similarities between b-HDL biodistribution studies irrespectively of the b-HDL design, whereas the biodistribution of the b-HDL components (lipids and scaffold) differ significantly. The b-HDL lipids primarily accumulate in liver, while the b-HDL scaffold primarily accumulates in the kidney. Furthermore, both b-HDL lipids and scaffold accumulate well in the tumor tissue in tumor-bearing mice. Finally, we present essential considerations and strategies for b-HDL labeling, and discuss how the b-HDL biodistribution can be tuned through particle design and administration route. Our meta-analysis and discussions provide a detailed overview of the fate of b-HDL in mice that is highly relevant when applying b-HDL for drug delivery or in vivo imaging applications.

Modulating barriers of tumor microenvironment through nanocarrier systems for improved cancer immunotherapy: a review of current status and future perspective

Cancer immunotherapy suppresses and destroys tumors by re-activating and sustaining the tumor-immune process, and thus improving the immune response of the body to the tumor. Immunotherapeutic strategies are showing promising results in pre-clinical and clinical trials, however, tumor microenvironment (TME) is extremely immunosuppressive. Thus, their translation from labs to clinics still faces issues. Recently, nanomaterial-based strategies have been developed to modulate the TME for robust immunotherapeutic responses. The combination of nanotechnology with immunotherapy potentiates the effectiveness of immunotherapy by increasing delivery and retention, and by reducing immunomodulation toxicity. This review aims to highlight the barriers offered by TME for hindering the efficiency of immunotherapy for cancer treatment. Next, we highlight various nano-carriers based strategies for modulating those barriers for achieving better therapeutic efficacy of cancer immunotherapy with higher safety. This review will add to the body of scientific knowledge and will be a good reference material for academia and industries.

Current Progresses and Challenges of Immunotherapy in Triple-Negative Breast Cancer

With improved understanding of the immunogenicity of triple-negative breast cancer (TNBC), immunotherapy has emerged as a promising candidate to treat this lethal disease owing to the lack of specific targets and effective treatments. While immune checkpoint inhibition (ICI) has been effectively used in immunotherapy for several types of solid tumor, monotherapies targeting programmed death 1 (PD-1), its ligand PD-L1, or cytotoxic T lymphocyte-associated protein 4 (CTLA-4) have shown little efficacy for TNBC patients. Over the past few years, various therapeutic candidates have been reviewed, attempting to improve ICI efficacy on TNBC through combinatorial treatment. In this review, we describe the clinical limitations of ICI and illustrate candidates from an immunological, pharmacological, and metabolic perspective that may potentiate therapy to improve the outcomes of TNBC patients.

Therapeutic Vaccines for Cancer Immunotherapy

The rapid development of nanobiotechnology has enabled progress in therapeutic cancer vaccines. These vaccines stimulate the host innate immune response by tumor antigens followed by a cascading adaptive response against cancer. However, an improved antitumor immune response is still in high demand because of the unsatisfactory clinical performance of the vaccine in tumor inhibition and regression. To date, a complicated tumor immunosuppressive environment and suboptimal design are the main obstacles for therapeutic cancer vaccines. The optimization of tumor antigens, vaccine delivery pathways, and proper adjuvants for innate immune response initiation, along with reprogramming of the tumor immunosuppressive environment, is essential for therapeutic cancer vaccines in triggering an adequate antitumor immune response. In this review, we aim to review the challenges in and strategies for enhancing the efficacy of therapeutic vaccines. We start with the summary of the available tumor antigens and their properties and then the optimal strategies for vaccine delivery. Subsequently, the vaccine adjuvants focused on the intrinsic adjuvant properties of nanostructures are further discussed. Finally, we summarize the combination strategies with therapeutic cancer vaccines and discuss their positive impact in cancer immunity.

Recent Advances on Rare Earth Upconversion Nanomaterials for Combined Tumor Near-Infrared Photoimmunotherapy

Cancer has been threatening the safety of human life. In order to treat cancer, many methods have been developed to treat tumor, such as traditional therapies like surgery, chemotherapy, radiotherapy, as well as new strategies like photodynamic therapy, photothermal therapy, sonodynamic therapy, and other emerging therapies. Although there are so many ways to treat tumors, these methods all face the dilemma that they are incapable to cope with metastasis and recurrence of tumors. The emergence of immunotherapy has given the hope to conquer the challenge. Immunotherapy is to use the body's own immune system to stimulate and maintain a systemic immune response to form immunological memory, resist the metastasis and recurrence of tumors. At the same time, immunotherapy can combine with other treatments to exhibit excellent antitumor effects. Upconversion nanoparticles (UCNPs) can convert near-infrared (NIR) light into ultraviolet and visible light, thus have good performance in bioimaging and NIR triggered phototherapy. In this review paper, we summarize the design, fabrication, and application of UCNPs-based NIR photoimmunotherapy for combined cancer treatment, as well as put forward the prospect of future development.

The progress and perspective of nanoparticle-enabled tumor metastasis treatment

As one of the most serious threats to human being, cancer is hard to be treated when metastasis happens. What's worse, there are few identified targets of metastasis for drug development. Therefore, it is important to develop strategies to prevent metastasis or treat existed metastasis. This review focuses on the procedure of metastasis, and first summarizes the targeting delivery strategies, including primary tumor targeting drug delivery, tumor metastasis targeting drug delivery and hijacking circulation cells. Then, as a promising treatment, the application of immunotherapy in tumor metastasis treatment is introduced, and strategies that stimulating immune response are reviewed, including chemotherapy, photothermal therapy, photodynamic therapy, ferroptosis, sonodynamic therapy, and nanovaccines. Finally, the challenges and perspective about nanoparticle-enabled tumor metastasis treatment are discussed.

Liposomal Delivery of Mitoxantrone and a Cholesteryl Indoximod Prodrug Provides Effective Chemo-immunotherapy in Multiple Solid Tumors

We developed a custom-designed liposome carrier for codelivery of a potent immunogenic cell death (ICD) stimulus plus an inhibitor of the indoleamine 2,3-dioxygenase (IDO-1) pathway to establish a chemo-immunotherapy approach for solid tumors in syngeneic mice. The carrier was constructed by remote import of the anthraquinone chemotherapeutic agent, mitoxantrone (MTO), into the liposomes, which were further endowed with a cholesterol-conjugated indoximod (IND) prodrug in the lipid bilayer. For proof-of-principle testing, we used IV injection of the MTO/IND liposome in a CT26 colon cancer model to demonstrate the generation of a robust immune response, characterized by the appearance of ICD markers (CRT and HMGB-1) as well as evidence of cytotoxic cancer cell death, mediated by perforin and granzyme B. Noteworthy, the cytotoxic effects involved natural killer (NK) cell, which suggests a different type of ICD response. The immunotherapy response was significantly augmented by codelivery of the IND prodrug, which induced additional CRT expression, reduced number of Foxp3+ Treg, and increased perforin release, in addition to extending animal survival beyond the effect of an MTO-only liposome. The outcome reflects the improved pharmacokinetics of MTO delivery to the cancer site by the carrier. In light of the success in the CT26 model, we also assessed the platform efficacy in further breast cancer (EMT6 and 4T1) and renal cancer (RENCA) models, which overexpress IDO-1. Encapsulated MTO delivery was highly effective for inducing chemo-immunotherapy responses, with NK participation, in all tumor models. Moreover, the growth inhibitory effect of MTO was enhanced by IND codelivery in EMT6 and 4T1 tumors. All considered, our data support the use of encapsulated MTO delivery for chemo-immunotherapy, with the possibility to boost the immune response by codelivery of an IDO-1 pathway inhibitor.

Combination of Irreversible Electroporation and STING Agonist for Effective Cancer Immunotherapy

Recently, cancer immunotherapy has received attention as a viable solution for the treatment of refractory tumors. However, it still has clinical limitations in its treatment efficacy due to inter-patient tumor heterogeneity and immunosuppressive tumor microenvironment (TME). In this study, we demonstrated the triggering of anti-cancer immune responses by a combination of irreversible electroporation (IRE) and a stimulator of interferon genes (STING) agonist. Optimal electrical conditions inducing damage-associated molecular patterns (DAMPs) by immunogenic cell death (ICD) were determined through in vitro 2D and 3D cell experiments. In the in vivo syngeneic lung cancer model, the combination of IRE and STING agonists demonstrated significant tumor growth inhibition. We believe that the combination strategy of IRE and STING agonists has potential for effective cancer immunotherapy.

Engineered Nanoparticles for Cancer Vaccination and Immunotherapy

The immune system has evolved over time to protect the host from foreign microorganisms. Activation of the immune system is predicated on a distinction between self and nonself. Unfortunately, cancer is characterized by genetic alterations in the host's cells, leading to uncontrolled cellular proliferation and evasion of immune surveillance. Cancer immunotherapy aims to educate the host's immune system to not only recognize but also attack and kill mutated cancer cells. While immune checkpoint blockers have been proven to be effective against multiple types of advanced cancer, the overall patient response rate still remains below 30%. Therefore, there is an urgent need to improve current cancer immunotherapies. In this Account, we present an overview of our recent progress on nanoparticle-based strategies for improving cancer vaccines and immunotherapies. We also present other complementary strategies to give a well-rounded snapshot of the field of combination cancer immunotherapy. The versatility and tunability of nanoparticles make them promising platforms for addressing individual challenges posed by various cancers. For example, nanoparticles can deliver cargo materials to specific cells, such as vaccines delivered to antigen-presenting cells for strong immune activation. Nanoparticles also allow for stimuli-responsive delivery of various therapeutics to cancer cells, thus forming the basis for combination cancer immunotherapy. Here, we focus on nanoparticle platforms engineered to deliver tumor antigens, whole tumor cells, and chemotherapeutic or phototherapeutic agents in a manner to effectively and safely trigger the host's immune system against tumor cells. For each work, we discuss the nanoparticle platform developed, synthesis chemistry, and in vivo applications. Nanovaccines offer a unique platform for codelivery of personalized tumor neoantigens and adjuvants and elicitation of robust immune responses against aggressive tumors. Nanovaccines either delivering whole tumor cell lysate or formed from tumor cell lysate may increase the repertoire of tumor antigens as immune targets while exploiting immunogenic cell death to prime antitumor immune responses. We also discuss how antigen- and whole tumor cell-based approaches may open the door for personalized cancer vaccination and immunotherapy. On the other hand, chemotherapy, phototherapy, and radiotherapy are more standardized cancer therapies, and nanoparticle-based approaches may promote their ability to initiate T cell activation against tumor cells and improve antitumor efficacy with minimal toxicity. Finally, building on the recent progress in nanoparticle-based cancer immunotherapy, the field should set the ultimate goal to be clinical translation and clinical efficacy. We will discuss regulatory, analytical, and manufacturing hurdles that should be addressed to expedite the clinical translation of nanomedicine-based cancer immunotherapy.

Mitoxantrone-Loaded Nanoparticles for Magnetically Controlled Tumor Therapy-Induction of Tumor Cell Death, Release of Danger Signals and Activation of Immune Cells

Stimulating the patient’s immune system represents a promising therapeutic strategy to fight cancer. However, low immunogenicity of the tumor cells within an immune suppressive milieu often leads to weak anti-tumor immune responses. Additionally, the immune system may be impaired by accompanying aggressive chemotherapies. We show that mitoxantrone, bound to superparamagnetic iron oxide nanoparticles (SPIONs) as the transport system, can be magnetically accumulated in adherent HT-29 colon carcinoma cells, thereby inducing the same cell death phenotype as its soluble counterpart, a chemotherapeutic agent and prototypic inductor of immunogenic cell death. The nanoparticle-loaded drug induces cell cycle stop, apoptosis and secondary necrosis in a dose- and time-dependent manner comparable to the free drug. Cell death was accompanied by the release of interleukin-8 and damage-associated molecular patterns (DAMPs) such as HSP70 and ATP, which fostered chemotactic migration of monocytes and maturation of dendritic cells. We furthermore ensured absence of endotoxin contaminations and compatibility with erythrocytes and platelets and investigated the influence on plasma coagulation in vitro. Summarizing, with magnetic enrichment, mitoxantrone can be accumulated at the desired place, sparing healthy peripheral cells and tissues, such as immune cells. Conserving immune competence in cancer patients in the future might allow combined therapeutic approaches with immune therapies (e.g., checkpoint inhibitors).

Post translational modification-assisted cancer immunotherapy for effective breast cancer treatment

Post translational modifications (PTM) such as phosphorylation are often correlated with tumorigenesis and malignancy in breast cancer. Herein, we report a PTM-assisted strategy as a simplified version of a personalized cancer vaccine for enhanced cancer immunotherapy. Titanium modified dendritic mesoporous silica nanoparticles (TiDMSN) are applied to assist the specific enrichment of phosphorylated tumor antigens released upon immunogenic cell death. This strategy significantly improved the tumor inhibition efficacy in a bilateral breast cancer model and the expansion of both CD8+ and CD4+ T cells in the distant tumor site. The nanotechnology based PTM-assisted strategy provides a simple and generalizable methodology for effective personalized cancer immunotherapy.

Eliciting Immunogenic Cell Death via a Unitized Nanoinducer

Utilizing chemotherapeutics to induce immunogenic cell death (ICD) is a promising strategy to sensitize tumor cells and induce anticancer immunity. However, the application of traditional ICD inducers, such as chemodrugs, is largely hindered by their low tumor selectivity and severe side effects. Here, a new unitized ICD nanoinducer with high potency and cancer cell specificity is reported to achieve effective cancer immunotherapy. This nanoinducer is composed of disulfide-bond-incorporated organosilica nanoparticles, curcumin (CUR), and iron oxide nanoparticles, which can deplete intracellular glutathione, produce hydroxyl radicals, and induce cancer-cell-specific Ca²⁺ depletion as well as thioredoxin reductase inhibition. While the components are unable to induce ICD individually, their complementary pharmaceutical activities significantly elevate intracellular oxidative stress and endoplasmic reticulum stress in parallel. Consequently, ICD and systemic antitumor immunity can be elicited. Compared to the conventional ICD inducer doxorubicin, the unitized nanoinducer exhibits significantly improved ICD-inducing activity and cancer cell selectivity.

Application prospect of peptide-modified nano targeting drug delivery system combined with PD-1/PD-L1 based immune checkpoint blockade in glioblastoma

Glioblastoma (GBM) is a type of primary malignant brain tumor with low median survival time, high recurrence rate and poor prognosis. The blood-brain barrier (BBB) and the diffuse infiltration of invasive GBM cells lead to a lower efficacy of traditional treatment. Recently, nanocarriers have become a promising method of brain drug delivery due to their ability to effectively cross the BBB. Especially, the peptide-modified nanocarriers can enhance the permeability, targeting and efficacy of chemotherapeutic agents against GBM. Moreover, the clinical application of immune checkpoint blockade (ICB) therapy in cancer treatment has attracted increasing attention, and the programmed death-1 receptor (PD-1) and PD-ligand-1 (PD-L1) monoclonal antibodies are considered to be a possible therapy for GBM. Consequently, we review the advances both in peptide-modified nano targeted drug delivery system and PD-1/PD-L1 based ICB in GBM treatment, and propose a new strategy combining the two methods, which may provide a novel approach for GBM treatment.

Self-Assembled Nanoparticles: Exciting Platforms for Vaccination

Vaccination is successfully advanced to control several fatal diseases and improve human life expectancy. However, additional innovations are required in this field because there are no effective vaccines to prevent some infectious diseases. The shift from the attenuated or inactivated pathogens to safer but less immunogenic protein or peptide antigens has led to a search for effective antigen delivery carriers that can function as both antigen vehicles and intrinsic adjuvants. Among these carriers, self-assembled nanoparticles (SANPs) have shown great potential to be the best representative. For the nanoscale and multiple presentation of antigens, with accurate control over size, geometry, and functionality, these nanoparticles are assembled spontaneously and mimic pathogens, resulting in enhanced antigen presentation and increased cellular and humoral immunity responses. In addition, they may be applied through needle-free routes due to their adhesive ability, which gives them a great future in vaccination applications. This review provides an overview of various SANPs and their applications in prophylactic vaccines.

Tumor-Activated Size-Enlargeable Bioinspired Lipoproteins Access Cancer Cells in Tumor to Elicit Anti-Tumor Immune Responses

The limited lymphocytes infiltration and immunosuppression in tumor are the major challenges of cancer immunotherapy. The use of immunogenic cell death (ICD)-inducing agents has potential to potentiate antitumor immune responses, but is tremendously hampered by the poor delivery efficiency. Herein, a tumor-activated size-enlargeable bioinspired lipoprotein of oxaliplatin (TA-OBL) is designed to access cancer cells and boost the ICD-induced antitumor immunity for synergizing immune-checkpoint blockades (ICBs)-mediated immunotherapy. TA-OBL is constructed by integrating a legumain-sensitive melittin conjugate for improving intratumoral permeation and cancer cell accessibility, a pH-sensitive phospholipid for triggering size-enlargement and drug release in intracellular acidic environments, a nitroreductase-sensitive hydrophobic oxaliplatin prodrug (N-OXP) for eliciting antitumor immunity into the bioinspired nano-sized lipoprotein system. TA-OBL treatment produced robust antitumor immune responses and its combination with ICBs demonstrates strong therapeutic benefits with delayed tumor growth and extended survival rate, making it a promising delivery nanoplatform to elicit antitumor immunity for cancer immunotherapy.

"Layer peeling" co-delivery system for enhanced RNA interference-based tumor associated macrophages-specific chemoimmunotherapy

RNA interference (RNAi)-based immunotherapy combined with chemotherapy has emerged as a promising therapeutic strategy for cancer treatment. The transport of siRNA and small molecular agents from the tumor vasculature to a separate therapeutic target has been impeded by multiple physiological barriers, which has restricted the development of RNAi-based chemoimmunotherapy. A nanotechnology-based co-delivery system was superior in improving the co-localization of gene and drug in the same tumor cell, while a co-delivery system for chemoimmunotherapy was expected to realize xenotype cell-targeting, which means delivering immunotherapy agents and chemotherapy drugs to immune cells and tumor cells, respectively. A multilayer structure co-delivery system was outstanding in crossing these barriers and targeting different cells in tumor tissue. Herein, a "layer peeling" co-delivery system (CDMPR) was developed with co-loaded IKKβ-siRNA and doxorubicin (DOX), in which IKKβ-siRNA was used for RNAi-based tumor associated macrophages (TAMs) polarization for immunotherapy and DOX was used for chemotherapy. A transwell assay in vitro and an immunofluorescence assay in Hepa1-6 tumor-bearing mice indicated that CDMPR exhibited a pH-sensitive disassembly ability in tumor tissue, IKKβ-siRNA was precisely delivered to M2-type TAMs and DOX was internalized into tumor cells. An M2-type TAMs polarization ability study of CDMPR demonstrated that M2-type TAMs could be polarized to M1-type TAMs by CDMPR in vitro and in vivo. In Hepa1-6 tumor-bearing mice, CDMPR exhibited improved antitumor efficiency with M2-type re-polarization ability by the precise delivery of IKKβ-siRNA and DOX to M2-type TAMs and tumor cells, respectively. Consequently, the combination of RNAi-based TAMs polarization and chemotherapy by the "layer peeling" co-delivery system would achieve an enhanced chemoimmunotherapy effect, which provides a novel strategy to improve cancer therapeutic effects.

Cell and tissue engineering in lymph nodes for cancer immunotherapy

In cancer, lymph nodes (LNs) coordinate tumor antigen presentation necessary for effective antitumor immunity, both at the levels of local cellular interactions and tissue-level organization. In this review, we examine how LNs may be engineered to improve the therapeutic outcomes of cancer immunotherapy. At the cellular scale, targeting the LNs impacts the potency of cancer vaccines, immune checkpoint blockade, and adoptive cell transfer. On a tissue level, macro-scale biomaterials mimicking LN features can function as immune niches for cell reprogramming or delivery in vivo, or be utilized in vitro to enable preclinical testing of drugs and vaccines. We additionally review strategies to induce ectopic lymphoid sites reminiscent of LNs that may improve antitumor T cell priming.

Bacteria-triggered tumor-specific thrombosis to enable potent photothermal immunotherapy of cancer

We discovered that attenuated Salmonella after intravenous injection would proliferate within various types of solid tumors but show rapid clearance in normal organs, without rendering notable toxicity. Bacteria-induced inflammation would trigger thrombosis in the infected tumors by destroying tumor blood vessels. Six types of tested tumors would all turn into darkened color with strong near-infrared absorbance, as observed by photoacoustic imaging. Under laser irradiation, those bacterial-infected tumors would be effectively ablated. Because of the immune-stimulation function, such bacteria-based photothermal therapy (PTT) would subsequently trigger antitumor immune responses, which could be further enhanced by immune checkpoint blockade to effectively suppress the growth of abscopal tumors. A robust immune memory effect to reject rechallenged tumors is also observed after bacteria-based PTT. Our work demonstrates that bacteria by themselves could act as a tumor-specific PTT agent to enable photoimmunotherapy cancer therapy to inhibit tumor metastasis and recurrence.

Polymer nanomedicines

Polymer nanomedicines (macromolecular therapeutics, polymer-drug conjugates, drug-free macromolecular therapeutics) are a group of biologically active compounds that are characterized by their large molecular weight. This review focuses on bioconjugates of water-soluble macromolecules with low molecular weight drugs and selected proteins. After analyzing the design principles, different structures of polymer carriers are discussed followed by the examination of the efficacy of the conjugates in animal models and challenges for their translation into the clinic. Two innovative directions in macromolecular therapeutics that depend on receptor crosslinking are highlighted: a) Combination chemotherapy of backbone degradable polymer-drug conjugates with immune checkpoint blockade by multivalent polymer peptide antagonists; and b) Drug-free macromolecular therapeutics, a new paradigm in drug delivery.

NIR-Triggered Sequentially Responsive Nanocarriers Amplified Cascade Synergistic Effect of Chemo-Photodynamic Therapy with Inspired Antitumor Immunity

A desirable cancer therapeutic strategy is supposed to have effective ability to not only exert maximum anticancer ability but also inspire antitumor immunity for preventing tumor relapse and metastasis. During this research, multifunctional upconversion nanoparticles (UCNPs) coated by ROS-responsive micelles are prepared for tumor targeting and near-infrared (NIR)-triggered photodynamic therapy (PDT)-combined synergistic effect of chemotherapy. Moreover, both PDT and chemotherapy agents could activate antitumor immunity via inducing immunogenic cell death with CD8⁺ and CD4⁺ T cells infiltrating in tumors. Through the experiments, intravenous administration of multifunctional nanocarriers with noninvasive NIR irradiation destroys the orthotopic tumors and efficiently suppresses lung metastasis in a metastatic triple-negative breast cancer model by cascade-amplifying chemo-PDT and systemic antitumor immunity. In conclusion, this study provides prospective chemo-PDT with inspired antitumor immunity for metastatic cancer treatment.

Lipid-Based Drug Delivery Nanoplatforms for Colorectal Cancer Therapy

Colorectal cancer (CRC) is a prevalent disease worldwide, and patients at late stages of CRC often suffer from a high mortality rate after surgery. Adjuvant chemotherapeutics (ACs) have been extensively developed to improve the survival rate of such patients, but conventionally formulated ACs inevitably distribute toxic chemotherapeutic drugs to healthy organs and thus often trigger severe side effects. CRC cells may also develop drug resistance following repeat dosing of conventional ACs, limiting their effectiveness. Given these limitations, researchers have sought to use targeted drug delivery systems (DDSs), specifically the nanotechnology-based DDSs, to deliver the ACs. As lipid-based nanoplatforms have shown the potential to improve the efficacy and safety of various cytotoxic drugs (such as paclitaxel and vincristine) in the clinical treatment of gastric cancer and leukemia, the preclinical progress of lipid-based nanoplatforms has attracted increasing interest. The lipid-based nanoplatforms might be the most promising DDSs to succeed in entering a clinical trial for CRC treatment. This review will briefly examine the history of preclinical research on lipid-based nanoplatforms, summarize the current progress, and discuss the challenges and prospects of using such approaches in the treatment of CRC.

Insights into Nanomedicine for Immunotherapeutics in Squamous Cell Carcinoma of the head and neck

Immunotherapies such as immune checkpoint blockade benefit only a portion of patients with head and neck squamous cell carcinoma. The multidisciplinary field of nanomedicine is emerging as a promising strategy to achieve maximal anti-tumor effect in cancer immunotherapy and to turn non-responders into responders. Various methods have been developed to deliver therapeutic agents that can overcome bio-barriers, improve therapeutic delivery into the tumor and lymphoid tissues and reduce adverse effects in normal tissues. Additional modification strategies also have been employed to improve targeting and boost cytotoxic T cell-based immune responses. Here, we review the state-of-the-art use of nanotechnologies in the laboratory, in advanced preclinical phases as well as those running through clinical trials assessing their advantages and challenges.

A Review on Nano-Based Drug Delivery System for Cancer Chemoimmunotherapy

Although notable progress has been made on novel cancer treatments, the overall survival rate and therapeutic effects are still unsatisfactory for cancer patients. Chemoimmunotherapy, combining chemotherapeutics and immunotherapeutic drugs, has emerged as a promising approach for cancer treatment, with the advantages of cooperating two kinds of treatment mechanism, reducing the dosage of the drug and enhancing therapeutic effect. Moreover, nano-based drug delivery system (NDDS) was applied to encapsulate chemotherapeutic agents and exhibited outstanding properties such as targeted delivery, tumor microenvironment response and site-specific release. Several nanocarriers have been approved in clinical cancer chemotherapy and showed significant improvement in therapeutic efficiency compared with traditional formulations, such as liposomes (Doxil®, Lipusu®), nanoparticles (Abraxane®) and micelles (Genexol-PM®). The applications of NDDS to chemoimmunotherapy would be a powerful strategy for future cancer treatment, which could greatly enhance the therapeutic efficacy, reduce the side effects and optimize the clinical outcomes of cancer patients. Herein, the current approaches of cancer immunotherapy and chemoimmunotherapy were discussed, and recent advances of NDDS applied for chemoimmunotherapy were further reviewed.

Engineering nanomedicines through boosting immunogenic cell death for improved cancer immunotherapy

Current cancer immunotherapy has limited response rates in a large variety of solid tumors partly due to the low immunogenicity of the tumor cells and the immunosuppressive tumor microenvironment (ITM). A number of clinical cancer treatment modalities, including radiotherapy, chemotherapy, photothermal and photodynamic therapy, have been shown to elicit immunogenicity by inducing immunogenic cell death (ICD). However, ICD-based immunotherapy is restricted by the ITM limiting its efficacy in eliciting a long-term antitumor immune response, and by severe systemic toxicity. To address these challenges, nanomedicine-based drug delivery strategies have been exploited for improving cancer immunotherapy by boosting ICD of the tumor cells. Nanosized drug delivery systems are promising for increasing drug accumulation at the tumor site and codelivering ICD inducers and immune inhibitors to simultaneously elicit the immune response and relieve the ITM. This review highlights the recent advances in nanomedicine-based immunotherapy utilizing ICD-based approaches. A perspective on the clinical translation of nanomedicine-based cancer immunotherapy is also provided.

Nanomedicine and Onco-Immunotherapy: From the Bench to Bedside to Biomarkers

The broad relationship between the immune system and cancer is opening a new hallmark to explore for nanomedicine. Here, all the common and synergy points between both areas are reviewed and described, and the recent approaches which show the progress from the bench to the beside to biomarkers developed in nanomedicine and onco-immunotherapy.

Nanomedicine in Non-Small Cell Lung Cancer: From Conventional Treatments to Immunotherapy

Non-small cell lung cancer (NSCLC) remains the most common cause of cancer-related mortality. The heterogeneous nature of this disease hinders its diagnosis and treatment, requiring continuous advances in research aiming to understand its intricate nature. Consequently, the retrospective analysis of conventional therapies has allowed the introduction of novel tools provided by nanotechnology, leading to considerable improvements in clinical outcomes. Furthermore, the development of novel immunotherapies based on the recently understood interaction of the immune system with the tumor highlights the real possibility of definitively treating NSCLC from its early stages. Novel engineering approaches in nanomedicine will enable to overcome the intrinsic limits of conventional and emerging therapies regarding off-site cytotoxicity, specificity, resistance mechanisms, and administration issues. The convergence point of these therapies with nanotechnology lays the foundation for achieving currently unmet needs.

Supramolecular Self-Assembled Nanostructures for Cancer Immunotherapy

Functional materials and nanostructures have been widely used for enhancing the therapeutic potency and safety of current cancer immunotherapy. While profound nanostructures have been developed to participate in the development of cancer immunotherapy, the construction of intricate nanostructures with easy fabrication and functionalization properties to satisfy the diversified requirements in cancer immunotherapy are highly required. Hierarchical self-assembly using supramolecular interactions to manufacture organized architectures at multiple length scales represents an interesting and promising avenue for sophisticated nanostructure construction. In this mini-review, we will outline the recent progress made in the development of supramolecular self-assembled nanostructures for cancer immunotherapy, with special focus on the supramolecular interactions including supramolecular peptide assembly, supramolecular DNA assembly, lipid hydrophobic assembly, host-guest assembly, and biomolecular recognition assembly.

Co-delivery of doxorubicin and epacadostat via heparin coated pH-sensitive liposomes to suppress the lung metastasis of melanoma

High metastasis is responsible for the failure in the treatment of melanoma. Chemoimmunotherapy has shown conspicuous inhibition effects not only on the growth of tumor in situ, but also on the metastasis to distant organs. Given that the indoleamine-2,3 dioxygenase (IDO) overexpressed in the microenvironment of tumor leads to the immune escape, the combination of chemotherapeutic drug and IDO inhibitor might be a promising chemoimmunotherapy. Besides, the hematogenous metastasis mediated by platelets was supposed to be blocked by the heparin (HP). Therefore, a drug delivery system with all these elements involved might be a potential treatment for melanoma. Here, we developed a pH-sensitive liposomal dual-delivery system for doxorubicin (DOX) and epacadostat (EPA) with HP coated (HP/LDE). It was confirmed to enhance cytotoxicity and apoptosis, reverse the platelets-activated epithelial mesenchymal transformation (EMT) and prevent the invasion and migration in vitro. After systemic administration, HP/LDE provided the optimum anti-metastasis effect on the melanoma. The results of evaluation on DC maturation, CD8⁺ cytotoxic T lymphocytes (CTLs) activation and T cell mediated cytotoxicity were consistent in vitro and in vivo. Taken together, our study established a functional liposomal dual-delivery system with ideal anti-metastasis efficacy on melanoma.

Combining Doxorubicin-Loaded PEGylated Poly(Lactide-co-glycolide) Nanoparticles with Checkpoint Inhibition Safely Enhances Therapeutic Efficacy in a Melanoma Model

Doxorubicin (DOX) has been widely used for the treatment of various cancers, however, the use of soluble DOX is limited by its low therapeutic index and improved formulations are therefore sought. Aside from its tumoricidal properties, DOX has also been shown to cause an immunogenic form of cell death, however, it is becoming abundantly clear that in situ immune stimulation alone is insufficient to cause significant immune based antitumor activity and that immune checkpoint modulation is also required. In this study, DOX-loaded nanoparticles were made by nanoprecipitation of DOX with a PEGylated poly(lactide-co-glycolide) copolymer (DOX-PLGA-PEG NPs) and were then tested in combination with immune checkpoint blockade (antiprogrammed death (anti-PD-1)) in a murine melanoma model to enhance antitumor effectiveness. Results showed the prepared particles to be approximately 134 nm in diameter (zeta potential -22 mV) with a loading of 1.75 μg DOX/mg NPs. In vitro release studies (of DOX) revealed the NPs to exhibit a 12 h burst release phase, followed by a slower release phase for up to 200 h. Survival studies of mice challenged with B16.F10 melanoma cells, revealed 60% of mice treated with the combination of DOX-PLGA-PEG NPs plus anti-PD-1 were tumor-free at the completion of the study. This combination therapy demonstrated higher antitumor efficacy in vivo compared to control, soluble DOX, and monotherapy of DOX-PLGA-PEG NPs or anti-PD-1 solution (p < 0.05). Moreover, in vivo safety studies (mouse weight/histopathological/toxicity) were investigated and results suggested that the combination therapy was safe. In conclusion, this study demonstrates the successful fabrication of DOX-loaded NPs by a nanoprecipitation method, and when combined with checkpoint inhibition could provide significant therapy in a murine melanoma model, suggesting that the DOX-PLGA-PEG NPs may be generating immune stimulation in situ and that benefit from this combination may be obtained in a clinical setting in the future.

Supramolecular prodrug hydrogelator as an immune booster for checkpoint blocker-based immunotherapy

Immune checkpoint blockers (ICBs) have shown great promise at harnessing immune system to combat cancer. However, only a fraction of patients can directly benefit from the anti-programmed cell death protein 1 (aPD1) therapy, and the treatment often leads to immune-related adverse effects. In this context, we developed a prodrug hydrogelator for local delivery of ICBs to boost the host's immune system against tumor. We found that this carrier-free therapeutic system can serve as a reservoir for extended tumoral release of camptothecin and aPD1 antibody, resulting in an immune-stimulating tumor microenvironment for boosted PD-1 blockade immune response. Our in vivo results revealed that this combination chemoimmunotherapy elicits robust and durable systemic anticancer immunity, inducing tumor regression and inhibiting tumor recurrence and metastasis. This work sheds important light into the use of small-molecule prodrugs as both chemotherapeutic and carrier to awaken and enhance antitumor immune system for improved ICBs therapy.

Synthetic Immunogenic Cell Death Mediated by Intracellular Delivery of STING Agonist Nanoshells Enhances Anticancer Chemo-immunotherapy

Many favorable anticancer treatments owe their success to the induction immunogenic cell death (ICD) in cancer cells, which results in the release of endogenous danger signals along with tumor antigens for effective priming of anticancer immunity. We describe a strategy to artificially induce ICD by delivering the agonist of stimulator of interferon genes (STING) into tumor cells using hollow polymeric nanoshells. Following intracellular delivery of exogenous adjuvant, subsequent cytotoxic treatment creates immunogenic cellular debris that spatiotemporally coordinate tumor antigens and STING agonist in a process herein termed synthetic immunogenic cell death (sICD). sICD is indiscriminate to the type of chemotherapeutics and enables colocalization of exogenously administered immunologic adjuvants and tumor antigens for enhanced antigen presentation and anticancer adaptive response. In three mouse tumor models, sICD enhances therapeutic efficacy and restrains tumor progression. The study highlights the benefit of delivering STING agonists to cancer cells, paving ways to new chemo-immunotherapeutic designs.