Delivery technologies for cancer immunotherapy

One-Step Self-Assembly of Multifunctional DNA Nanohydrogels: An Enhanced and Harmless Strategy for Guiding Combined Antitumor Therapy

DNA nanostructure-based drug delivery system (DDS) has become an advanced therapeutic strategy for cancer because of its unsurpassed editability, intrinsic biodegradability, and tunable multifunctionality. An intelligent DNA nanosystem integrating targeting, immunostimulation, and chemotherapy was constructed based on unmethylated cytosine-phosphate-guanine oligonucleotides (CpG ODNs) DNA nanohydrogels (CpG-MUC1-hydrogel). By facile one-step self-assembly, the cross-shaped DNAs (C-DNAs) assembled from pH-responsive I-motif sequences and targeted MUC1 aptamer-immunoadjuvant CpG-fused sequences (CpG-MUC1) were integrated into DNA nanohydrogels with controllable size by the hybridization of DNA linkers. Subsequently, DOX was successively intercalated into the base pairs of CpG-MUC1-hydrogel, resulting in CpG-MUC1-hydrogel/Dox that would disassemble and release DOX and CpGs at acidic conditions. After MUC1-mediated internalization, CpG-MUC1-hydrogel/Dox dissociated in the endo/lysosomes and induced favorable apoptosis of tumor cells. Afterward, liberated CpGs triggered vast cytokine secretion from immune cells which elicited potent immune response against malignancy. Notably, CpG-MUC1-hydrogel induced an apoptosis effect on MCF-7 cells via significantly increasing the Bax/Bcl₂ ratios and a higher level of tumor necrosis factor (TNF-α) on RAW264.7 cells than naked CpGs. Our results demonstrated that self-assembled CpG-MUC1-hydrogel represented an attractive DDS for precise delivery, potent immunostimulating activity, and considerable combination efficiency with few adverse effects, which is expected to make breakthroughs in clinical translation.

Synthetic 3D scaffolds for cancer immunotherapy

Recent clinical success of systemic cancer immunotherapy has paved the way for the next-generation therapeutics. Nevertheless, cancer immunotherapies, in particular combination therapies, are associated in some cases with severe side effects and low response rates. Synthetic scaffolds have emerged as a promising platform to deliver immunotherapeutic agents locally. Placed at strategic locations of the body, scaffolds can reduce side effects while increasing the concentration of the agent at the site of interest. Moreover, scaffolds can mimic the context, in which biochemical cues are presented in vivo to enhance cell modulation. Recent research has focused on designing three-dimensional (3D) scaffolds with specific properties to modulate the antitumor response at various stages of the cancer immunity cycle. As the number of immunotherapies in clinical trials is soaring, it is essential to critically evaluate the role that scaffolds can play in improving the safety and efficacy of existing and future therapies.

Exploiting Current Understanding of Hypoxia Mediated Tumour Progression for Nanotherapeutic Development

Hypoxia is one of the most common phenotypes of malignant tumours. Hypoxia leads to the increased activity of hypoxia-inducible factors (HIFs), which regulate the expression of genes controlling a raft of pro-tumour phenotypes. These include maintenance of the cancer stem cell compartment, epithelial-mesenchymal transition (EMT), angiogenesis, immunosuppression, and metabolic reprogramming. Hypoxia can also contribute to the tumour progression in a HIF-independent manner via the activation of a complex signalling network pathway, including JAK-STAT, RhoA/ROCK, NF-κB and PI3/AKT. Recent studies suggest that nanotherapeutics offer a unique opportunity to target the hypoxic microenvironment, enhancing the therapeutic window of conventional therapeutics. In this review, we summarise recent advances in understanding the impact of hypoxia on tumour progression, while outlining possible nanotherapeutic approaches for overcoming hypoxia-mediated resistance.

Overview of Current Immunotherapies Targeting Mutated KRAS Cancers

The occurrence of somatic substitution mutations of the KRAS proto-oncogene is highly prevalent in certain cancer types, which often leads to constant activation of proliferative pathways and subsequent neoplastic transformation. It is often seen as a gateway mutation in carcinogenesis and has been commonly deemed as a predictive biomarker for poor prognosis and relapse when conventional chemotherapeutics are employed. Additionally, its mutational status also renders EGFR targeted therapies ineffective owing to its downstream location. Efforts to discover new approaches targeting this menacing culprit have been ongoing for years without much success, and with incidences of KRAS positive cancer patients being on the rise, researchers are now turning towards immunotherapies as the way forward. In this scoping review, recent immunotherapeutic developments and advances in both preclinical and clinical studies targeting K-ras directly or indirectly via its downstream signal transduction machinery will be discussed. Additionally, some of the challenges and limitations of various K-ras targeting immunotherapeutic approaches such as vaccines, adoptive T cell therapies, and checkpoint inhibitors against KRAS positive cancers will be deliberated.

Recruitment of CD103+ dendritic cells via tumor-targeted chemokine delivery enhances efficacy of checkpoint inhibitor immunotherapy

Although a clinical breakthrough for cancer treatment, it remains that a minority of patients respond to checkpoint inhibitor (CPI) immunotherapy. The composition of tumor-infiltrating immune cells has been identified as a key factor influencing CPI therapy success. Thus, enhancing tumor immune cell infiltration is a critical challenge. A lack of the chemokine CCL4 within the tumor microenvironment leads to the absence of CD103+ dendritic cells (DCs), a crucial cell population influencing CPI responsiveness. Here, we use a tumor stroma-targeting approach to deliver CCL4; by generating a fusion protein of CCL4 and the collagen-binding domain (CBD) of von Willebrand factor, we show that CBD fusion enhances CCL4 tumor localization. Intravenous CBD-CCL4 administration recruits CD103+ DCs and CD8+ T cells and improves the antitumor effect of CPI immunotherapy in multiple tumor models, including poor responders to CPI. Thus, CBD-CCL4 holds clinical translational potential by enhancing efficacy of CPI immunotherapy.

Nanomedicine-Based Immunotherapy for the Treatment of Cancer Metastasis

Metastasis is the leading cause of cancer-associated death, with poor prognosis even after extensive treatment. The dormancy of metastatic cancer cells during dissemination or after colony formation is one major reason for treatment failure, as most drugs target cells of active proliferation. Immunotherapy has shown great potential in cancer therapy because the activity of effector cells is less affected by the metabolic status of cancer cells. In addition, metastatic cells out of immunosuppressive tumor microenvironment (TME) are more susceptible to immune clearance, although these cells can achieve immune surveillance evasion via strategies such as platelet and macrophage recruitment. Since nanomaterials themselves or their carried drugs have the capability to modulate the immune system, a great amount of focus has been placed on nanomedicine strategies that leverage immune cells participating the metastatic cascade. These nanomedicines successfully inhibit the tumor metastasis and prolong the survival of model animals. Immune cells that are involved in the metastasis cascade are first summarized and then recent and inspiring strategies and nanomaterials in this growing field are highlighted.

Advanced Nanotechnology Leading the Way to Multimodal Imaging-Guided Precision Surgical Therapy

Surgical resection is the primary and most effective treatment for most patients with solid tumors. However, patients suffer from postoperative recurrence and metastasis. In the past years, emerging nanotechnology has led the way to minimally invasive, precision and intelligent oncological surgery after the rapid development of minimally invasive surgical technology. Advanced nanotechnology in the construction of nanomaterials (NMs) for precision imaging-guided surgery (IGS) as well as surgery-assisted synergistic therapy is summarized, thereby unlocking the advantages of nanotechnology in multimodal IGS-assisted precision synergistic cancer therapy. First, mechanisms and principles of NMs to surgical targets are briefly introduced. Multimodal imaging based on molecular imaging technologies provides a practical method to achieve intraoperative visualization with high resolution and deep tissue penetration. Moreover, multifunctional NMs synergize surgery with adjuvant therapy (e.g., chemotherapy, immunotherapy, phototherapy) to eliminate residual lesions. Finally, key issues in the development of ideal theranostic NMs associated with surgical applications and challenges of clinical transformation are discussed to push forward further development of NMs for multimodal IGS-assisted precision synergistic cancer therapy.

Sequential MR Image-Guided Local Immune Checkpoint Blockade Cancer Immunotherapy Using Ferumoxytol Capped Ultralarge Pore Mesoporous Silica Carriers after Standard Chemotherapy

Herein, ferumoxytol (Fer) capped antiprogrammed cell death-ligand 1 (PD-L1) antibodies (aPD-L1) loaded ultralarge pore mesoporous silica nanoparticles (Fer-ICB-UPMSNPs) are formulated for a sequential magnetic resonance (MR) image guided local immunotherapy after cabazitaxel (Cbz) chemotherapy for the treatment of prostate cancer (PC). The highly porous framework of UPMSNP provides a large capacity for aPD-L1. Fer capping of the pores extends the period of aPD-L1 release and provides MR visibility of the aPD-L1 loaded UPMSNP. As-chosen Cbz chemotherapy prior to the local immunotherapy induces strong immunogenic cell death, dendritic cell maturation, and upregulation of PD-L1 of tumor cells. Finally, tumor growth inhibition of sequential MR image-guided local delivery of Fer-ICB-UPMSNPs and a tumor specific adoptive immune reaction are demonstrated in the pretreated Tramp C1 PC mouse model with Cbz chemotherapy. The tumor suppression is superior to those obtained with systemic ICB treatment after Cbz, only Fer-ICB-UPMSNP or only Cbz. As a proof-of concept, MR image-guided local ICB immunotherapy using Fer-ICB-UPMSNPs after chemotherapy suggests a new perspective of translational local immunotherapy for patients who are treated with standard chemotherapies.

Metronidazole-functionalized iron oxide nanoparticles for molecular detection of hypoxic tissues

Being crucial under several pathological conditions, tumors, and tissue engineering, the MRI tracing of hypoxia within cells and tissues would be improved by the use of nanosystems allowing for direct recognition of low oxygenation and further treatment-oriented development. In the present study, we functionalized dendron-coated iron oxide nanoparticles (dendronized IONPs) with a bioreductive compound, a metronidazole-based ligand, to specifically detect the hypoxic tissues. Spherical IONPs with an average size of 10 nm were obtained and then decorated with the new metronidazole-conjugated dendron. The resulting nanoparticles (metro-NPs) displayed negligible effects on cell viability, proliferation, and metabolism, in both monolayer and 3D cell culture models, and a good colloidal stability in bio-mimicking media, as shown by DLS. Overtime quantitative monitoring of the IONP cell content revealed an enhanced intracellular retention of metro-NPs under anoxic conditions, confirmed by the in vitro MRI of cell pellets where a stronger negative contrast generation was observed in hypoxic primary stem cells and tumor cells after labeling with metro-NPs. Overall, these results suggest desirable properties in terms of interactions with the biological environment and capability of selective accumulation into the hypoxic tissue, and indicate that metro-NPs have considerable potential for the development of new nano-platforms especially in the field of anoxia-related diseases and tissue engineered models.

Emerging Marine Immunomodulatory Small-molecules (2010- Present)

Background:

Immunomodulation-based therapy has achieved a breakthrough in the last decade, which stimulates the passion of searching for potential immunomodulatory substances in recent years.

Objective:

Marine natural products are a unique source of immunomodulatory substances. This paper summarized the emerging marine natural small-molecules and related synthesized derivatives with immunomodulatory activities to provide readers an overview of these bioactive molecules and their potential in immunomodulation therapy.

Conclusion:

An increasing number of immunomodulatory marine small-molecules with diverse intriguing structure-skeletons were discovered. They may serve as a basis for further studies of marine natural products for their chemistry, related mechanism of action and structure- activity relationships.

Nanoparticles versus Dendritic Cells as Vehicles to Deliver mRNA Encoding Multiple Epitopes for Immunotherapy

The efficacy of antigen-specific immunotherapy relies heavily on efficient antigen delivery to antigen-presenting cells and engagement of as many disease-relevant T cells as possible in various lymphoid tissues, which are challenging to achieve. Here, we compared two approaches to deliver mRNA encoding multiple epitopes targeting both CD4⁺ and CD8⁺ T cells: a lipid-based nanoparticle platform to target endogenous antigen-presenting cells in vivo versus ex vivo mRNA-electroporated dendritic cells. After intraperitoneal injection, the nanoparticle platform facilitated efficient entry of mRNA into various endogenous antigen-presenting cells, including lymph node stromal cells, and elicited robust T cell responses within a wider network of lymphoid tissues compared with dendritic cells. Following intravenous injection, mRNA-electroporated dendritic cells and the nanoparticle platform localized primarily in lung and spleen, respectively. When administered locally via an intradermal route, both platforms resulted in mRNA expression at the injection site and in robust T cell responses in draining lymph nodes. This study indicates that multiple epitopes, customizable for specific patient populations and encoded by mRNA, can be targeted to different lymphoid tissues based on delivery vehicle and route, and constitute the groundwork for future studies using mRNA to reprogram exogenous or endogenous APCs for immunotherapy.

Intracellular tracking of drug release from pH-sensitive polymeric nanoparticles via FRET for synergistic chemo-photodynamic therapy

BACKGROUND

Synergistic therapy of tumor is a promising way in curing cancer and in order to achieve effective tumor therapy with real-time drug release monitoring, dynamic cellular imaging and antitumor activity.

RESULTS

In this work, a polymeric nanoparticle with Forster resonance energy transfer (FRET) effect and chemo-photodynamic properties was fabricated as the drug vehicle. An amphiphilic polymer of cyclo(RGDfCSH) (cRGD)-poly(ethylene glycol) (PEG)-Poly(L-histidine) (PH)-poly(ε-caprolactone) (PCL)-Protoporphyrin (Por)-acting as both a photosensitizer for photodynamic therapy (PDT) and absorption of acceptor in FRET was synthesized and self-assembled into polymeric nanoparticles with epirubicin (EPI)-acting as an antitumor drug for chemotherapy and fluorescence of donor in FRET. Spherical EPI-loaded nanoparticles with the average size of 150 ± 2.4 nm was procured with negatively charged surface, pH sensitivity and high drug loading content (14.9 ± 1.5%). The cellular uptake of EPI-loaded cRGD-PEG-PH-PCL-Por was monitored in real time by the FRET effect between EPI and cRGD-PEG-PH-PCL-Por. The polymeric nanoparticles combined PDT and chemotherapy showed significant anticancer activity both in vitro (IC50 = 0.47 μg/mL) and better therapeutic efficacy than that of free EPI in vivo.

CONCLUSIONS

This work provided a versatile strategy to fabricate nanoassemblies for intracellular tracking of drug release and synergistic chemo-photodynamic therapy.

The potential mechanism, recognition and clinical significance of tumor pseudoprogression after immunotherapy

As immunotherapy has gained increasing interest as a new foundation for cancer therapy, some atypical response patterns, such as pseudoprogression and hyperprogression, have garnered the attention of physicians. Pseudoprogression is a phenomenon in which an initial increase in tumor size is observed or new lesions appear, followed by a decrease in tumor burden; this phenomenon can benefit patients receiving immunotherapy but often leads to premature discontinuation of treatment owing to the false judgment of progression. Accurately recognizing pseudoprogression is also a challenge for physicians. Because of the extensive attention on pseudoprogression, significant progress has been made. Some new criteria for immunotherapy, such as irRC, iRECIST and imRECIST, were proposed to accurately evaluate the response to immunotherapy. Many new detection indexes, such as ctDNA and IL-8, have also been used to identify pseudoprogression. In this review, the definition, evaluation criteria, mechanism, monitoring, management and prognosis of pseudoprogression are summarized, and diagnostic and treatment processes for patients with progression but with a suspicion of pseudoprogression are proposed; these processes could be helpful for physicians in clinical practice and enhances the understanding of pseudoprogression.

Smart cancer nanomedicine

Nanomedicines are extensively employed in cancer therapy. We here propose four strategic directions to improve nanomedicine translation and exploitation. (1) Patient stratification has become common practice in oncology drug development. Accordingly, probes and protocols for patient stratification are urgently needed in cancer nanomedicine, to identify individuals suitable for inclusion in clinical trials. (2) Rational drug selection is crucial for clinical and commercial success. Opportunistic choices based on drug availability should be replaced by investments in modular (pro)drug and nanocarrier design. (3) Combination therapies are the mainstay of clinical cancer care. Nanomedicines synergize with pharmacological and physical co-treatments, and should be increasingly integrated in multimodal combination therapy regimens. (4) Immunotherapy is revolutionizing the treatment of cancer. Nanomedicines can modulate the behaviour of myeloid and lymphoid cells, thereby empowering anticancer immunity and immunotherapy efficacy. Alone and especially together, these four directions will fuel and foster the development of successful cancer nanomedicine therapies.

Overview of Immune Checkpoint Inhibitors Therapy for Hepatocellular Carcinoma, and The ITA.LI.CA Cohort Derived Estimate of Amenability Rate to Immune Checkpoint Inhibitors in Clinical Practice

Despite progress in our understanding of the biology of hepatocellular carcinoma (HCC), this tumour remains difficult-to-cure for several reasons, starting from the particular disease environment where it arises—advanced chronic liver disease—to its heterogeneous clinical and biological behaviour. The advent, and good results, of immunotherapy for cancer called for the evaluation of its potential application also in HCC, where there is evidence of intra-hepatic immune response activation. Several studies advanced our knowledge of immune checkpoints expression in HCC, thus suggesting that immune checkpoint blockade may have a strong rationale even in the treatment of HCC. According to this background, initial studies with tremelimumab, a cytotoxic T-lymphocyte-associated protein 4 (CTLA-4) inhibitor, and nivolumab, a programmed cell death protein 1 (PD-1) antibody, showed promising results, and further studies exploring the effects of other immune checkpoint inhibitors, alone or with other drugs, are currently underway. However, we are still far from the identification of the correct setting, and sequence, where these drugs might be used in clinical practice, and their actual applicability in real-life is unknown. This review focuses on HCC immunobiology and on the potential of immune checkpoint blockade therapy for this tumour, with a critical evaluation of the available trials on immune checkpoint blocking antibodies treatment for HCC. Moreover, it assesses the potential applicability of immune checkpoint inhibitors in the real-life setting, by analysing a large, multicentre cohort of Italian patients with HCC.

Decellularized Lymph Node Scaffolding as a Carrier for Dendritic Cells to Induce Anti-Tumor Immunity

In recent decades, the decellularized extracellular matrix (ECM) has shown potential as a promising scaffold for tissue regeneration. In this study, an organic acid decellularized lymph node (dLN) was developed as a carrier for dendritic cells (DCs) to induce antitumor immunity. The dLNs were prepared by formic acid, acetic acid, or citric acid treatment. The results showed highly efficient removal of cell debris from the lymph node and great preservation of ECM architecture and biomolecules. In addition, bone marrow dendritic cells (BMDCs) grown preferably inside the dLN displayed the maturation markers CD80, CD86, and major histocompatibility complex (MHC)-II, and they produced high levels of interleukin (IL)-1β, IL-6, and IL-12 cytokines when stimulated with ovalbumin (OVA) and CpG oligodeoxynucleotides (CPG-ODN). In an animal model, the BMDC-dLN completely rejected the E.G7-OVA tumor. Furthermore, the splenocytes from BMDC-dLN-immunized mice produced more interferon gamma, IL-4, IL-6, and IL-2, and they had a higher proliferation rate than other groups when re-stimulated with OVA. Hence, BMDC-dLN could be a promising DC-based scaffold for in vivo delivery to induce potent antitumor immunity.

Metal-Phenolic Coatings as a Platform to Trigger Endosomal Escape of Nanoparticles

The intracellular delivery of functional nanoparticles (NPs) and the release of therapeutic payloads at a target site are central issues for biomedical applications. However, the endosomal entrapment of NPs typically results in the degradation of active cargo, leading to poor therapeutic outcomes. Current advances to promote the endosomal escape of NPs largely involve the use of polycationic polymers and cell-penetrating peptides (CPPs), which both can suffer from potential toxicity and convoluted synthesis/conjugation processes. Herein, we report the use of metal-phenolic networks (MPNs) as versatile and nontoxic coatings to facilitate the escape of NPs from endo/lysosomal compartments. The MPNs, which were engineered from the polyphenol tannic acid and Fe^III or Al^III, enabled the endosomal escape of both inorganic (mesoporous silica) and organic (polystyrene and melamine resin) NPs owing to the "proton-sponge effect" arising from the buffering capacity of MPNs. Postfunctionalization of the MPN-coated NPs with low-fouling polymers did not impair the endosomal escape, indicating the modular and generalizable nature of this approach. We envisage that the ease of fabrication, versatility, low cytotoxicity, and promising endosomal escape performance displayed by the MPN coatings offer opportunities for such coatings to be used for the efficient delivery of cytoplasm-targeted therapeutics using NPs.

Engineering Nanoparticles to Reprogram the Tumor Immune Microenvironment for Improved Cancer Immunotherapy

Immunotherapy is rapidly maturing towards extensive clinical use. However, it does not work well in large patient populations because of an immunosuppressed microenvironment and limited reinvigoration of antitumor immunity. The tumor microenvironment is a complex milieu in which the principles of physiology and anatomy are defied and which is considered an immune-privileged site promoting T cell exhaustion. Tremendous research interest exists in developing nanoparticle-based approaches to modulate antitumor immune responses. The increasing use of immunotherapies in the clinic requires robust programming of immune cells to boost antitumor immunity. This review summarizes recent advances in the engineering of nanoparticles for improved anticancer immunotherapy. It discusses emerging nanoparticle-based approaches for the modulation of tumor cells and immune cells, such as dendritic cells, T cells and tumor-associated macrophages, with the intention to overcome challenges currently faced in the clinic. Furthermore, this review describes potentially curative combination therapeutic approaches to provoke effective tumor antigen-specific immune responses. We foresee a future in which improvement in patient's surveillance will become a mainstream practice.

Advances in Engineering Cells for Cancer Immunotherapy

Cancer immunotherapy aims to utilize the host immune system to kill cancer cells. Recent representative immunotherapies include T-cell transfer therapies, such as chimeric antigen receptor T cell therapy, antibody-based immunomodulator therapies, such as immune checkpoint blockade therapy, and cytokine therapies. Recently developed therapies leveraging engineered cells for immunotherapy against cancers have been reported to enhance antitumor efficacy while reducing side effects. Such therapies range from biologically, chemically and physically -engineered cells to bioinspired and biomimetic nanomedicines. In this review, advances of engineering cells for cancer immunotherapy are summarized, and prospects of this field are discussed.

Recent advances and challenges of repurposing nanoparticle-based drug delivery systems to enhance cancer immunotherapy

Cancer immunotherapy is an attractive treatment option under clinical settings. However, the major challenges of immunotherapy include limited patient response, limited tumor specificity, immune-related adverse events, and immunosuppressive tumor microenvironment. Therefore, nanoparticle (NP)-based drug delivery has been used to not only increase the efficacy of immunotherapeutic agents, but it also significantly reduces the toxicity. In particular, NP-based drug delivery systems alter the pharmacokinetic (PK) profile of encapsulated or conjugated immunotherapeutic agents to targeted cancer cells or immune cells and facilitate the delivery of multiple therapeutic combinations to targeted cells using single NPs. Recently, advanced NP-based drug delivery systems were effectively utilized in cancer immunotherapy to reduce the toxic side effects and immune-related adverse events. Repurposing these NPs as delivery systems of immunotherapeutic agents may overcome the limitations of current cancer immunotherapy. In this review, we focus on recent advances in NP-based immunotherapeutic delivery systems, such as immunogenic cell death (ICD)-inducing drugs, cytokines and adjuvants for promising cancer immunotherapy. Finally, we discuss the challenges facing current NP-based drug delivery systems that need to be addressed for successful clinical application.

Emergent Nanotechnological Strategies for Systemic Chemotherapy against Melanoma

Melanoma is an aggressive form of skin cancer, being one of the deadliest cancers in the world. The current treatment options involve surgery, radiotherapy, targeted therapy, immunotherapy and the use of chemotherapeutic agents. Although the last approach is the most used, the high toxicity and the lack of efficacy in advanced stages of the disease have demanded the search for novel bioactive molecules and/or efficient drug delivery systems. The current review aims to discuss the most recent advances on the elucidation of potential targets for melanoma treatment, such as aquaporin-3 and tyrosinase. In addition, the role of nanotechnology as a valuable strategy to effectively deliver selective drugs is emphasized, either incorporating/encapsulating synthetic molecules or natural-derived compounds in lipid-based nanosystems such as liposomes. Nanoformulated compounds have been explored for their improved anticancer activity against melanoma and promising results have been obtained. Indeed, they displayed improved physicochemical properties and higher accumulation in tumoral tissues, which potentiated the efficacy of the compounds in pre-clinical experiments. Overall, these experiments opened new doors for the discovery and development of more effective drug formulations for melanoma treatment.

Tumor Targeting Strategies of Smart Fluorescent Nanoparticles and Their Applications in Cancer Diagnosis and Treatment

Advantages such as strong signal strength, resistance to photobleaching, tunable fluorescence emissions, high sensitivity, and biocompatibility are the driving forces for the application of fluorescent nanoparticles (FNPs) in cancer diagnosis and therapy. In addition, the large surface area and easy modification of FNPs provide a platform for the design of multifunctional nanoparticles (MFNPs) for tumor targeting, diagnosis, and treatment. In order to obtain better targeting and therapeutic effects, it is necessary to understand the properties and targeting mechanisms of FNPs, which are the foundation and play a key role in the targeting design of nanoparticles (NPs). Widely accepted and applied targeting mechanisms such as enhanced permeability and retention (EPR) effect, active targeting, and tumor microenvironment (TME) targeting are summarized here. Additionally, a freshly discovered targeting mechanism is introduced, termed cell membrane permeability targeting (CMPT), which improves the tumor-targeting rate from less than 5% of the EPR effect to more than 50%. A new design strategy is also summarized, which is promising for future clinical targeting NPs/nanomedicines design. The targeting mechanism and design strategy will inspire new insights and thoughts on targeting design and will speed up precision medicine and contribute to cancer therapy and early diagnosis.

Improving cancer immunotherapy through nanotechnology

The 2018 Nobel Prize in Physiology or Medicine was awarded to pioneers in the field of cancer immunotherapy, as the utility of leveraging a patient's coordinated and adaptive immune system to fight the patient's unique tumour has now been validated robustly in the clinic. Still, the proportion of patients who respond to immunotherapy remains modest (~15% objective response rate across indications), as tumours have multiple means of immune evasion. The immune system is spatiotemporally controlled, so therapies that influence the immune system should be spatiotemporally controlled as well, in order to maximize the therapeutic index. Nanoparticles and biomaterials enable one to program the location, pharmacokinetics and co-delivery of immunomodulatory compounds, eliciting responses that cannot be achieved upon administration of such compounds in solution. The convergence of cancer immunotherapy, nanotechnology, bioengineering and drug delivery is opportune, as each of these fields has matured independently to the point that it can now be used to complement the others substantively and rationally, rather than modestly and empirically. As a result, unmet needs increasingly can be addressed with deductive intention. This Review explores how nanotechnology and related approaches are being applied to augmenting both endogenous leukocytes and adoptively transferred ones by informing specificity, influencing localization and improving function.

Red blood cell-derived nanoerythrosome for antigen delivery with enhanced cancer immunotherapy

Erythrocytes or red blood cells (RBCs) represent a promising cell-mediated drug delivery platform due to their inherent biocompatibility. Here, we developed an antigen delivery system based on the nanoerythrosomes derived from RBCs, inspired by the splenic antigen-presenting cell targeting capacity of senescent RBCs. Tumor antigens were loaded onto the nanoerythrosomes by fusing tumor cell membrane-associated antigens with nanoerythrosomes. This tumor antigen-loaded nanoerythrosomes (nano-Ag@erythrosome) elicited antigen responses in vivo and, in combination with the anti-programmed death ligand 1 (PD-L1) blockade, inhibited the tumor growth in B16F10 and 4T1 tumor models. We also generated a tumor model showing that "personalized nano-Ag@erythrosomes" could be achieved by fusing RBCs and surgically removed tumors, which effectively reduced tumor recurrence and metastasis after surgery.

Self-Amplified Drug Delivery with Light-Inducible Nanocargoes to Enhance Cancer Immunotherapy

Chemoimmunotherapy by systemic administration of individual regimens suffers from inconsistent pharmacokinetics profiles, low tumor specificity, and severe side effects. Despite promising nanoparticle-based codelivery approaches in therapeutics, the pathophysiological barriers of solid tumors are a hurdle for tumor accumulation and deep penetration of the drug-loaded nanoparticles. A light-inducible nanocargo (LINC) for immunotherapy is reported. LINC is composed of a reduction-responsive heterodimer of photosensitizer pheophorbide A (PPa) and indoleamine 2,3-dioxygenase 1 (IDO-1) inhibitor, i.e., NLG919, and a light-activatable prodrug of oxaliplatin (OXA). LINC administrated through intravenous injection is passively accumulated at the tumor site to generate near-infrared (NIR) fluorescence signal. Under fluorescence imaging guidance, the first-wave of NIR laser irradiation induce reactive oxygen species (ROS) generation, trigger cleavage of the polyethylene glycol (PEG) corona, and thus promote tumor retention and deep penetration of LINC. When exposed to the second-wave NIR laser illumination, LINC efficiently elicits the immune response and promotes intratumoral infiltration of cytotoxic T lymphocytes (CTLs). Furthermore, NLG919 delivered by LINC reverses the immunosuppressive tumor microenvironment by suppressing IDO-1 activity. Chemoimmunotherapy with LINC inhibit the tumor growth, lung metastasis, and tumor recurrence. The light-inducible self-amplification strategy for improved drug delivery and immunotherapy shows potential.

Benefits of Nanomedicine for Therapeutic Intervention in Malignant Diseases

Cancer remains one of the most difficult to manage healthcare problems. The last two decades have been considered the golden age of cancer research, with major breakthroughs being announced on a regular basis. However, the major problem regarding cancer treatment is the incapability to selectively target cancer cells, with certain populations of tumors still remaining alive after treatment. The main focus of researchers is to develop treatments that are both effective and selective in targeting malignant cells. In this regard, bioavailability can be increased by overcoming the biological barriers encountered in the active agent’s pathway, creating carrier vehicles that have the ability to target malignant cells and effectively release the active agent. Since its appearance, nanomedicine has provided many answers to these challenges, but still, some expectations were not satisfied. In this review, we focused on the most recent developments in targeted drug delivery. Furthermore, a summary of different types of nanoparticles used to deliver active therapeutic agents in oncology is presented, along with details on the nanodrugs that were clinically approved by the Food and Drug Administration (FDA), until April 2019.

The Evolving Landscape of Biomarkers for Anti-PD-1 or Anti-PD-L1 Therapy

The administration of antibodies blocking the immune checkpoint molecules programmed cell death protein 1 (PD-1) or programmed cell death 1 ligand 1 (PD-L1) has evolved as a very promising treatment option for cancer patients. PD-1/PD-L1 inhibition has significantly enhanced expansion, cytokine secretion, and cytotoxic activity of CD4⁺ and CD8⁺ T lymphocytes, resulting in enhanced antitumor responses. Anti-PD-1 or anti-PD-L1 therapy has induced tumor regression and improved clinical outcome in patients with different tumor entities, including melanoma, non-small-cell lung cancer, and renal cell carcinoma. These findings led to the approval of various anti-PD-1 or anti-PD-L1 antibodies for the treatment of tumor patients. However, the majority of patients have failed to respond to this treatment modality. Comprehensive immune monitoring of clinical trials led to the identification of potential biomarkers distinguishing between responders and non-responders, the discovery of modes of treatment resistance, and the design of improved immunotherapeutic strategies. In this review article, we summarize the evolving landscape of biomarkers for anti-PD-1 or anti-PD-L1 therapy.

Interactions of Nanoparticles and Biosystems: Microenvironment of Nanoparticles and Biomolecules in Nanomedicine

Nanotechnology is a multidisciplinary science covering matters involving the nanoscale level that is being developed for a great variety of applications. Nanomedicine is one of these attractive and challenging uses focused on the employment of nanomaterials in medical applications such as drug delivery. However, handling these nanometric systems require defining specific parameters to establish the possible advantages and disadvantages in specific applications. This review presents the fundamental factors of nanoparticles and its microenvironment that must be considered to make an appropriate design for medical applications, mainly: (i) Interactions between nanoparticles and their biological environment, (ii) the interaction mechanisms, (iii) and the physicochemical properties of nanoparticles. On the other hand, the repercussions of the control, alter and modify these parameters in the biomedical applications. Additionally, we briefly report the implications of nanoparticles in nanomedicine and precision medicine, and provide perspectives in immunotherapy, which is opening novel applications as immune-oncology.

Intracellular Photothermal Delivery for Suspension Cells Using Sharp Nanoscale Tips in Microwells

Efficient intracellular delivery of biomolecules into cells that grow in suspension is of great interest for biomedical research, such as for applications in cancer immunotherapy. Although tremendous effort has been expended, it remains challenging for existing transfer platforms to deliver materials efficiently into suspension cells. Here, we demonstrate a high-efficiency photothermal delivery approach for suspension cells using sharp nanoscale metal-coated tips positioned at the edge of microwells, which provide controllable membrane disruption for each cell in an array. Self-aligned microfabrication generates a uniform microwell array with three-dimensional nanoscale metallic sharp tip structures. Suspension cells self-position by gravity within each microwell in direct contact with eight sharp tips, where laser-induced cavitation bubbles generate transient pores in the cell membrane to facilitate intracellular delivery of extracellular cargo. A range of cargo sizes were tested on this platform using Ramos suspension B cells with an efficiency of >84% for Calcein green (0.6 kDa) and >45% for FITC-dextran (2000 kDa), with retained viability of >96% and a throughput of >100 000 cells delivered per minute. The bacterial enzyme β-lactamase (29 kDa) was delivered into Ramos B cells and retained its biological activity, whereas a green fluorescence protein expression plasmid was delivered into Ramos B cells with a transfection efficiency of >58%, and a viability of >89% achieved.

Emerging modes-of-action in drug discovery

An increasing focus on complex biology to cure diseases rather than merely treat symptoms has transformed how drug discovery can be approached. Instead of activating or blocking protein function, a growing repertoire of drug modalities can be leveraged or engineered to hijack cellular processes, such as translational regulation or degradation mechanisms. Drug hunters can therefore access a wider arsenal of modes-of-action to modulate biological processes and this review summarises these emerging strategies by highlighting the most representative examples of these approaches.

Nanocatalytic Medicine

Catalysis and medicine are often considered as two independent research fields with their own respective scientific phenomena. Promoted by recent advances in nanochemistry, large numbers of nanocatalysts, such as nanozymes, photocatalysts, and electrocatalysts, have been applied in vivo to initiate catalytic reactions and modulate biological microenvironments for generating therapeutic effects. The rapid growth of research in biomedical applications of nanocatalysts has led to the concept of "nanocatalytic medicine," which is expected to promote the further advance of such a subdiscipline in nanomedicine. The high efficiency and selectivity of catalysis that chemists strived to achieve in the past century can be ingeniously translated into high efficacy and mitigated side effects in theranostics by using "nanocatalytic medicine" to steer catalytic reactions for optimized therapeutic outcomes. Here, the rationale behind the construction of nanocatalytic medicine is eludicated based on the essential reaction factors of catalytic reactions (catalysts, energy input, and reactant). Recent advances in this burgeoning field are then comprehensively presented and the mechanisms by which catalytic nanosystems are conferred with theranostic functions are discussed in detail. It is believed that such an emerging catalytic therapeutic modality will play a more important role in the field of nanomedicine.

Nanoparticles for nucleic acid delivery: Applications in cancer immunotherapy

Immunotherapy has recently emerged as a powerful tool for cancer treatment. Early clinical successes from cancer immunotherapy have led to a growing list of FDA approvals, and many new therapies are in clinical and preclinical development. Nucleic acid therapeutics, including DNA, mRNA, and genome editing systems, hold significant potential as a form of immunotherapy due to its robust use in cancer vaccination, adoptive T-cell therapy, and gene regulation. However, these therapeutics must overcome numerous delivery obstacles to be successful, including rapid in vivo degradation, poor uptake into target cells, required nuclear entry, and potential in vivo toxicity in healthy cells and tissues. Nanoparticle delivery systems have been engineered to overcome several of these barriers as a means to safely and effectively deliver nucleic acid therapeutics to immune cells. In this Review, we discuss the applications of nucleic acid therapeutics in cancer immunotherapy, and we detail how nanoparticle platforms have been designed to deliver mRNA, DNA, and genome editing systems to enhance the potency and safety of these therapeutics.

Displacement Affinity Release of Antibodies from Injectable Hydrogels

Current methods to tune release rates of therapeutic antibodies (Abs) for local delivery are complex and routinely require bioconjugations that may reduce Ab bioactivity. To rapidly tune release profiles of bioactive Abs, we developed a biophysical interaction system within a neutravidin modified poly(carboxybetaine) hydrogel (pCB-NT) that tunes release rates of desthiobiotinylated Abs (D-Abs) using a constant hydrogel and D-Ab combination. Herein, we delivered desthiobiotinylated bevacizumab (D-Bv), a recombinant humanized monoclonal IgG1 Ab for antiangiogenic cancer therapies. D-Bv's high affinity for pCB-NT (K_D 7.8 × 10^-10 M; t_1/2 ∼ 2 h) produces a slow D-Bv release rate (∼5 ng day^-1) that is increased by the dissolution of hydrogel encapsulated biotin derivative pellets, which displaces D-Bv from pCB-NT binding sites. In contrast to traditional affinity systems, displacement affinity release of Abs (DARA) does not require Ab or hydrogel modifications for each unique release rate. D-Bv release rates were tuned by simply altering the total biotin derivative concentration; the effective first-order (k_eff) and mass per day release rates were tuned 25- and 8-fold, respectively. Local surface plasmon resonance (LSPR) and biolayer interferometry (BLI) confirmed the D-Bv binding affinity for the corresponding ligand and Fc receptor, demonstrating that the biophysical interaction system is amenable to anticancer Abs for receptor or cytokine blockade and immune cell recruitment to cancer cells.

Syringeable immunotherapeutic nanogel reshapes tumor microenvironment and prevents tumor metastasis and recurrence

The low response rate of current cancer immunotherapy suggests the presence of few antigen-specific T cells and a high number of immunosuppressive factors in tumor microenvironment (TME). Here, we develop a syringeable immunomodulatory multidomain nanogel (iGel) that overcomes the limitation by reprogramming of the pro-tumoral TME to antitumoral immune niches. Local and extended release of immunomodulatory drugs from iGel deplete immunosuppressive cells, while inducing immunogenic cell death and increased immunogenicity. When iGel is applied as a local postsurgical treatment, both systemic antitumor immunity and a memory T cell response are generated, and the recurrence and metastasis of tumors to lungs and other organs are significantly inhibited. Reshaping of the TME using iGel also reverts non-responding groups to checkpoint blockade therapies into responding groups. The iGel is expected as an immunotherapeutic platform that can reshape immunosuppressive TMEs and synergize cancer immunotherapy with checkpoint therapies, with minimized systemic toxicity.

The limited efficacy of current immunotherapy suggests low antigen-specific T cells and immunosuppressive factors in tumor microenvironment (TME). Here, the authors develop a syringeable immunomodulatory multi-domain nanogel that can reprogram the TME and induce enhanced cancer immunotherapy.

Bioresponsive Protein Complex of aPD1 and aCD47 Antibodies for Enhanced Immunotherapy

Despite the promising efficacy of immune checkpoint blockade (ICB) in treating many types of cancers, the clinical benefits have often been restricted by the low objective response rates and systemic immune-related adverse events. Here, a bioresponsive ICB treatment is developed based on the reactive oxygen species (ROS)-sensitive protein complex for controlled sequential release of anti- "don't eat me" signal antibody (aCD47) and antiprogrammed cell death protein 1 (aPD1), by leveraging the abundant ROS in the tumor microenvironment (TME). These protein complexes can also act as scavengers of ROS in the TME to reverse the immunosuppressive responses, thereby enhancing antitumor efficacy in vivo. In a melanoma cancer model, the synergistic antitumor efficacy was achieved, which was accompanied by enhanced T cell immune responses together with reduced immunosuppressive responses.

Non-viral nano-immunotherapeutics targeting tumor microenvironmental immune cells

The tumor microenvironmental immune cells (TMICs) consists of myeloid cells (tumor-associated macrophages, dendritic cells, myeloid-derived suppressor cells, etc.) and lymphocytes (T cells and B cells), all of which could be immunologically suppressed through their interactions with cancer cells. Immunological understanding of the tumor microenvironment (TME) has led to great success in the development of clinical cancer immunotherapeutic. The most advanced cancer immunotherapies are chimeric antigen receptor-modified T cells (CAR-T cells) and checkpoint inhibiting antibodies blocking CTLA4, PD-1 and PD-L1. However, many hurdles remain that should be addressed for improved therapeutic efficacy and reduced side effects such as cytokine release syndrome and patient-death. In recent decades, nanoparticles have been demonstrated as an efficient drug delivery tool due to their ease of modification, biocompatibility and intrinsic tumor targeting effect, and also been applied for cancer immunotherapy. In this review, we briefly introduce the immunosuppressive functions of TMICs and review recent advances in the development of TMIC-targeted nanotherapeutics for cancer immunotherapy. Tumor-associated macrophage (TAM)-targeted systems have shown to deplete or repolarize macrophages to M1 state for anti-tumoral immune responses. Tumor-infiltrating T cell (TIT)-targeted strategies have provided the activation of effector T cells and suppression of regulatory T cells in tumor, overcoming the current hurdles of single regimen checkpoint inhibitors. Lastly, recent studies on dendritic cell-targeted mRNA vaccination are discussed and the future perspectives of nano-immunotherapeutic for next-generation of cancer immunotherapy is emphasized.

Molecular modelling of TLR agonist Pam3CSK4 entrapment in PLA nanoparticles as a tool to explain loading efficiency and functionality

Designing potent and safe-of-use therapies against cancers and infections remains challenging despite the emergence of novel molecule classes like checkpoint inhibitors or Toll-Like-Receptor ligands. The latest therapeutic perspectives under development for immune modulator administration exploits vectorization, and biodegradable delivery systems are one of the most promising vehicles. Nanoparticles based on Poly (D,L) Lactic Acid (PLA) as polymer for formulation are widely investigated due to its bioresorbable, biocompatible and low immunogen properties. We propose a PLA-based nanoparticle delivery system to vectorize Pam₃CSK₄, a lipopeptide TLR1/2 ligand and a potent activator of the proinflammatory transcription factor NF-κB that shows a self-assembling behavior from 30 µg/mL onwards. We demonstrate successful encapsulation of Pam₃CSK₄ in PLA nanoparticles by nanoprecipitation in a 40-180 µg/mL concentration range, with 99% of entrapment efficiency. By molecular modelling, we characterize drug/carrier interactions and conclude that Pam₃CSK₄ forms clusters onto the nanoparticle and is not encapsulated into the hydrophobic core. In silico predictions provide nanoprecipitation optimization and the mechanistic understanding of the particle dynamics. The loaded-Pam₃CSK₄ maintains bioactivity on TLR2, confirmed by in vitro experiments using reporter cell line HEK-Blue hTLR2. Our presented data and results are convincing evidence that Pam₃CSK₄-loaded in PLA nanoparticles represent a promising immune modulating system.

Novel Delivery Systems for Checkpoint Inhibitors

Checkpoint inhibition (CPI) therapies have been proven to be powerful clinical tools in treating cancers. FDA approvals and ongoing clinical development of checkpoint inhibitors for treatment of various cancers highlight the immense potential of checkpoint inhibitors as anti-cancer therapeutics. The occurrence of immune-related adverse events, however, is a major hindrance to the efficacy and use of checkpoint inhibitors as systemic therapies in a wide range of patients. Hence, methods of sustained and tumor-targeted delivery of checkpoint inhibitors are likely to improve efficacy while also decreasing toxic side effects. In this review, we summarize the findings of the studies that evaluated methods of tumor-targeted delivery of checkpoint inhibitors, review their strengths and weaknesses, and discuss the outlook for therapeutic use of these delivery methods.

Messenger RNA delivery by hydrazone-activated polymers

The intracellular delivery of DNA and RNA therapeutics requires the assistance of vectors and/or nucleotide modifications to protect the nucleic acids against host nucleases and promote cellular internalization and release. Recently, messenger RNA (mRNA) has attracted much attention due to its transient activity and lack of genome permanent recombination and persistent expression. Therefore, there is a strong interest in the development of conceptually new non-viral vectors with low toxicity that could improve mRNA transfection efficiency. We have recently introduced the potential of polyhydrazones and the importance of the degree of polymerization for the delivery of siRNA and plasmid DNA. Here, we demonstrate that this technology can be easily adapted to the more interesting complexation and delivery inside living cells of mRNA. The polyplexes resulting from the combination of the amphiphilic polyhydrazone were characterized and the transfection efficiency and cell viability were studied for a discrete collection of functionalized polyhydrazones. The results obtained demonstrated the versatility of these polymeric vectors as excellent candidates for the delivery of mRNA and validate the easy adaptability of the technology to more sensitive and therapeutically relevant nucleic acids.

Integrated Hydrogel Platform for Programmed Antitumor Therapy Based on Near Infrared-Triggered Hyperthermia and Vascular Disruption

Complete tumor regression is a great challenge faced by single therapy of near-infrared (NIR)-triggered hyperthermia or vascular disrupting agents. An injectable nanocomposite (NC) hydrogel is rationally designed for combined anticancer therapy based on NIR-triggered hyperthermia and vascular disruption. The NC hydrogel, codelivered with Prussian blue (PB) nanoparticles and combretastatin A4 (CA4), has good shear-thinning, self-recovery, and excellent photothermal properties. Because of the remarkable tumor-site retention and sustained release of CA4 (about 10% over 12 days), the NC hydrogel has a tumor suppression rate of 99.6%. The programmed combinational therapy conveys the concept of "attack + guard", where PB-based NIR irradiation imposes intensive attack on most of cancer cells, and CA4 serves as a guard against the tumor growth by cutting off the energy supply. Moreover, the biosafety and eco-friendliness of the hydrogel platform pave the way toward clinical applications.

Multifunctional nanocapsules on a seesaw balancing sonodynamic and photodynamic therapies against superficial malignant tumors by effective immune-enhancement

The effective strategy to treat superficial malignant tumors is challenging due to the complexed mechanisms for tumor growth inhibition. The proposed immune-enhancement and immune response activation pathways rely on the direct and massive implementation of therapeutic agents. In this manuscript, an alternative route has been developed to apply the multifunctional peptide amphiphile-Rose Bengal (RB) nanocapsules for noninvasive sonodynamic and photodynamic therapies in association with the targeted immune enhancement to tumor proliferation. The nanocapsules proved better RB loading capacity, comparable reactive oxygen species generation and improved B16 and HeLa cell killing capability. The proof-of-principle in-vivo nude mice therapy studies with routine blood examinations and cytokine analysis validated their effectiveness for tumor cell elimination, and a direct tumor vasculature damage for efficacious lesion necrosis, positive prognosis with minimized side-effects. This state-of-the-art strategy provides a promising route to merge tumor enhancement and tumor response activation methodologies, and is expected to be universalized for a broad spectra of cancer diseases.

Disorder of Coagulation-Fibrinolysis System: An Emerging Toxicity of Anti-PD-1/PD-L1 Monoclonal Antibodies

A disruption of immune checkpoints leads to imbalances in immune homeostasis, resulting in immune-related adverse events. Recent case studies have suggested the association between immune checkpoint inhibitors (ICIs) and the disorders of the coagulation-fibrinolysis system, implying that systemic immune activation may impact a balance between clotting and bleeding. However, little is known about the association of coagulation-fibrinolysis system disorder with the efficacy of ICIs. We retrospectively evaluated 83 lung cancer patients who received ICI at Kumamoto University Hospital. The association between clinical outcome and diseases associated with disorders of the coagulation-fibrinolysis system was assessed along with tumor PD-L1 expression. Among 83 NSCLC patients, total 10 patients (12%) developed diseases associated with the disorder of coagulation-fibrinolysis system. We found that disorders of the coagulation-fibrinolysis system occurred in patients with high PD-L1 expression and in the early period of ICI initiation. In addition, high tumor responses (72%) were observed, including two complete responses among these patients. Furthermore, we demonstrate T-cell activation strongly induces production of a primary initiator of coagulation, tissue factor in peripheral PD-L1^high monocytes, in vitro. This study suggests a previously unrecognized pivotal role for immune activation in triggering disorders of the coagulation-fibrinolysis system in cancer patients during treatment with ICI.

Application of PD-1 Blockade in Cancer Immunotherapy

The programmed cell death protein 1 (PD-1) pathway has received considerable attention due to its role in eliciting the immune checkpoint response of T cells, resulting in tumor cells capable of evading immune surveillance and being highly refractory to conventional chemotherapy. Application of anti-PD-1/PD-L1 antibodies as checkpoint inhibitors is rapidly becoming a promising therapeutic approach in treating tumors, and some of them have successfully been commercialized in the past few years. However, not all patients show complete responses and adverse events have been noted, suggesting a better understanding of PD-1 pathway mediated immunosuppression is needed to predict patient response and improve treatment efficacy. Here, we review the progresses on the studies of the mechanistic role of PD-1 pathway in the tumor immune evasion, recent clinical development and commercialization of PD-1 pathway inhibitors, the toxicities associated with PD-1 blockade observed in clinical trials as well as how to improve therapeutic efficacy and safety of cancer immunotherapy.