Applying nanotechnology to boost cancer immunotherapy by promoting immunogenic cell death

Self-Delivery Nanobooster to Enhance Immunogenic Cell Death for Cancer Chemoimmunotherapy

Inducing immunogenic cell death (ICD) is a promising strategy for cancer immunotherapy. Shikonin (SHK), a naphthoquinone compound from Lithospermum erythrorhizon, can stimulate antitumor immunity by inducing ICD. Nevertheless, the immunogenicity of tumor cells killed by SHK is weak. Endoplasmic reticulum (ER) stress is an important intracellular pathway of the ICD effect. Curcumin (CUR) can directly induce ER stress by disrupting Ca2+ homeostasis, which might enhance SHK-induced ICD effect. A self-delivery ICD effect nanobooster (CS-PEG NPs) was developed by the self-assembly of SHK (ICD inducer) and CUR (ICD enhancer) with the assistance of DSPE-PEG2K for cancer chemoimmunotherapy. CS-PEG NPs possessed effective CT26 tumor cell cellular uptake and tumor accumulation ability. Moreover, enhanced cytotoxicity against tumor cells and apoptosis promotion were achieved due to the synergistic effect of CUR and SHK. Notably, CS-PEG NPs induced obvious Ca2+ homeostasis disruption, ER stress, and ICD effect. Subsequently, the neoantigens produced by the robust ICD effect in vivo promoted dendritic cell maturation, which further recruited and activated cytotoxic T lymphocytes. Superior antitumor efficacy and systemic antitumor immunity were observed in the CT26-bearing BALB/c mouse model without side effects in major organs. This study offers a promising self-delivery nanobooster to induce strong ICD effect and antitumor immunity for cancer chemoimmunotherapy.

Shifting cold to hot tumors by nanoparticle-loaded drugs and products

Cold tumors lack antitumor immunity and are resistant to therapy, representing a major challenge in cancer medicine. Because of the immunosuppressive spirit of the tumor microenvironment (TME), this form of tumor has a low response to immunotherapy, radiotherapy, and also chemotherapy. Cold tumors have low infiltration of immune cells and a high expression of co-inhibitory molecules, such as immune checkpoints and immunosuppressive molecules. Therefore, targeting TME and remodeling immunity in cold tumors can improve the chance of tumor repression after therapy. However, tumor stroma prevents the infiltration of inflammatory cells and hinders the penetration of diverse molecules and drugs. Nanoparticles are an intriguing tool for the delivery of immune modulatory agents and shifting cold to hot tumors. In this review article, we discuss the mechanisms underlying the ability of nanoparticles loaded with different drugs and products to modulate TME and enhance immune cell infiltration. We also focus on newest progresses in the design and development of nanoparticle-based strategies for changing cold to hot tumors. These include the use of nanoparticles for targeted delivery of immunomodulatory agents, such as cytokines, small molecules, and checkpoint inhibitors, and for co-delivery of chemotherapy drugs and immunomodulatory agents. Furthermore, we discuss the potential of nanoparticles for enhancing the efficacy of cancer vaccines and cell therapy for overcoming resistance to treatment.

Synergistic Brilliance: Engineered Bacteria and Nanomedicine Unite in Cancer Therapy

Engineered bacteria are widely used in cancer treatment because live facultative/obligate anaerobes can selectively proliferate at tumor sites and reach hypoxic regions, thereby causing nutritional competition, enhancing immune responses, and producing anticancer microbial agents in situ to suppress tumor growth. Despite the unique advantages of bacteria-based cancer biotherapy, the insufficient treatment efficiency limits its application in the complete ablation of malignant tumors. The combination of nanomedicine and engineered bacteria has attracted increasing attention owing to their striking synergistic effects in cancer treatment. Engineered bacteria that function as natural vehicles can effectively deliver nanomedicines to tumor sites. Moreover, bacteria provide an opportunity to enhance nanomedicines by modulating the TME and producing substrates to support nanomedicine-mediated anticancer reactions. Nanomedicine exhibits excellent optical, magnetic, acoustic, and catalytic properties, and plays an important role in promoting bacteria-mediated biotherapies. The synergistic anticancer effects of engineered bacteria and nanomedicines in cancer therapy are comprehensively summarized in this review. Attention is paid not only to the fabrication of nanobiohybrid composites, but also to the interpromotion mechanism between engineered bacteria and nanomedicine in cancer therapy. Additionally, recent advances in engineered bacteria-synergized multimodal cancer therapies are highlighted.

A facile boronophenylalanine modified polydopamine dual drug-loaded nanoparticles for enhanced anti-tumor immune response in hepatocellular carcinoma comprehensive treatment

Hepatocellular carcinoma (HCC) has an insidious onset and high malignancy. Most patients have progressed to intermediate and advanced stages by the time of diagnosis, and the long-term efficacy of traditional treatments is not satisfactory. Immunotherapy has shown great promise in the treatment of HCC in recent years; however, the low immunogenicity and severe immunosuppressive tumor microenvironment result in a low response rate to immunotherapy in HCC patients. Therefore, it is of great significance to improve the immunogenicity of HCC and thus enhance its sensitivity to immunotherapy. Here, we prepared the boronophenylalanine-modified dual drug-loaded polydopamine nanoparticles by a facile method. This system used boronophenylalanine-modified polydopamine nanoparticles as a delivery vehicle and photothermal material for the chemotherapeutic drug doxorubicin and the immune agonist CpG oligodeoxynucleotides (CpG-ODN), with both active targeting and lysosomal escape functions. The cancer cells are rapidly killed by photothermal treatment, and then chemotherapy is used to further kill cancer cells that are inadequately treated by photothermal treatment. The combination of photothermal-chemotherapy synergistically induces the release of relevant antigens from tumor cells, thus initiating anti-tumor immunity; and then cooperates with CpG-ODN to trigger a powerful anti-tumor immune memory effect, potently and durably inhibiting HCC recurrence.

A programmable releasing versatile hydrogel platform boosts systemic immune responses via sculpting tumor immunogenicity and reversing tolerogenic dendritic cells

Immunogenicity improvement is a valuable strategy for tumor immunotherapy. However, immunosuppressive factors bestow tolerogenic phenotype on tumor-infiltrating DCs, which exhibit weak antigen presentation and strong anti-inflammatory cytokines secretion abilities, limiting the effectiveness of tumor immunotherapy even if the tumor has adequate immunogenicity. Herein, we designed a programmable releasing versatile hydrogel platform (PIVOT) to sculpt tumor immunogenicity, increase intratumoral DCs and cDC1s abundance, and reverse the tolerogenic phenotype of DCs, thus promoting their maturation for boosting innate and adaptive immune responses. Responsive to tumoral reactive oxygen species (ROS), the hydrogel splits and promotes the activation of DCs and macrophages. Then, oxaliplatin is first released from PIVOT to sculpt tumor immunogenicity by inducing immunogenic cell death (ICD) and causing tumoral DNA fragments exposure simultaneously. Subsequently, the impaired DNA fragments bind to high mobility group protein 1 (HMGB1) forming the DNA-HMGB1 complex. Moreover, exogenous FMS-like tyrosine kinase 3 ligand (Flt-3L) recruits masses of DCs, especially cDC1s, which will endocytose the complex benefiting from TIM-3 blockade (αTIM3) that can reverse tolerogenic DCs. Finally, the endocytosis activates the cGAS-STING pathway of cDC1s, which promotes the secretion of type I IFN that triggers innate immune responses, and CXCL9 which recruits CD8+ effector T cells to initiate the following adaptive immune response against tumor progress. PIVOT achieves nearly 90 % tumor growth inhibition and induces systemic antitumor immune responses. In conclusion, this study focuses on ICD-mediated tumor immunogenicity sculpture and nucleic acid endocytosis-involved tolerogenic DCs reversal, providing a novel paradigm for enhancing DCs-based antitumor immune responses.

Photothermal-Enhanced Dual Inhibition of Lactate/Kynurenine Metabolism for Promoting Tumor Immunotherapy

Traditionally referred to as "metabolic junk", lactate has now been recognized as essential "energy currency" and crucial "messenger" that contributes to tumor evolution, immunosuppression, etc., thus presenting a promising strategy for antitumor interventions. Similarly, kynurenine (Kyn) also exerts an immunosuppressive function, thereby significantly compromising the effectiveness of immunotherapy. This study proposes and validates a strategy for enhancing immunotherapy through photothermal-assisted depletion of lactate sustained by cycle-like O2 supply, with blocking the tryptophan (Trp)/Kyn metabolic pathway. In brief, a nanozyme therapeutic agent (PNDPL) is constructed, which mainly consists of PtBi nanozymes, lactate oxidase (LOX) and the indoleamine 2,3-dioxygenase (IDO) inhibitor NLG919. The PtBi nanozymes, which exhibit a catalase (CAT)-like activity, form a positive feedback loop with LOX to consume lactate while self-supplying O2 . Moreover, PtBi nanozymes retain enzyme-like performance even in a slightly acidic tumor microenvironment. Under 1064 nm irradiation, photothermal therapy (PTT) not only induces tumor cell death but also accelerates lactate exhaustion. Therefore, the combination of lactate depletion-induced starvation therapy and PTT, along with the blocking of IDO-mediated immune escape, effectively inhibits tumor growth and reverses immunosuppressive microenvironment, thus preventing tumor metastasis. This study represents the first investigation into the synergistic antitumor effects by lactate metabolism regulation and IDO-related immunotherapy.

Repolarizing Tumor-Associated Macrophages and inducing immunogenic cell Death: A targeted liposomal strategy to boost cancer immunotherapy

Cancer immunotherapy has shown promise in treating various malignancies. However, the presence of an immunosuppressive tumor microenvironment (TME) triggered by M2 tumor-associated macrophages (TAMs) and the limited tumor cell antigenicity have hindered its broader application. To address these challenges, we developed DOX/R837@ManL, a liposome loaded with imiquimod (R837) and doxorubicin (DOX), modified with mannose-polyethylene glycol (Man-PEG). DOX/R837@ManL employed a mannose receptor (MRC1)-mediated targeting strategy, allowing it to accumulate selectively at M2 Tumor associated macrophages (TAMs) and tumor sites. R837, an immune adjuvant, promoted the conversion of immunosuppressive M2 TAMs into immunostimulatory M1 TAMs, and reshaped the immunosuppressive TME. Simultaneously, DOX release induced immunogenic cell death (ICD) in tumor cells and enhanced tumor cell antigenicity by promoting dendritic cells (DCs) maturation. Through targeted delivery, the synergistic action of R837 and DOX activated innate immunity and coordinated adaptive immunity, enhancing immunotherapy efficacy. In vivo experiments have demonstrated that DOX/R837@ManL effectively eliminated primary tumors and lung metastases, while also preventing tumor recurrence post-surgery. These findings highlighted the potential of DOX/R837@ManL as a promising strategy for cancer immunotherapy.

Dual-responsive supramolecular photodynamic nanomedicine with activatable immunomodulation for enhanced antitumor therapy

A major challenge facing photodynamic therapy (PDT) is that the activity of the immune-induced infiltrating CD8+ T cells is subject to the regulatory T lymphocytes (Tregs), leaving the tumor at risk of recurrence and metastasis after the initial ablation. To augment the antitumor response and reprogram the immunosuppressive tumor microenvironment (TME), a supramolecular photodynamic nanoparticle (DACss) is constructed by the host-guest interaction between demethylcantharidin-conjugated β-cyclodextrin (DMC-CD) and amantadine-terminated disulfide-conjugated FFVLGGGC peptide with chlorin e6 decoration (Ad-ss-pep-Ce6) to achieve intelligent delivery of photosensitizer and immunomodulator for breast cancer treatment. The acid-labile β-carboxamide bond of DMC-CD is hydrolyzed in response to the acidic TME, resulting in the localized release of DMC and subsequent inhibition of Tregs. The guest molecule Ad-ss-pep-Ce6 can be cleaved by a high level of intracellular GSH, reducing photosensitizer toxicity and increasing photosensitizer retention in the tumor. With a significant increase in the CTL/Treg ratio, the combination of Ce6-based PDT and DMC-mediated immunomodulation adequately achieved spatiotemporal regulation and remodeling of the TME, as well as improved primary tumor and in situ lung metastasis suppression with the aid of PD-1 antibody.

Erythrocyte-Leveraged Oncolytic Virotherapy (ELeOVt): Oncolytic Virus Assembly on Erythrocyte Surface to Combat Pulmonary Metastasis and Alleviate Side Effects

Despite being a new promising tool for cancer therapy, intravenous delivery of oncolytic viruses (OVs) is greatly limited by poor tumor targeting, rapid clearance in the blood, severe organ toxicity, and cytokine release syndrome. Herein, a simple and efficient strategy of erythrocyte-leveraged oncolytic virotherapy (ELeOVt) is reported, which for the first time assembled OVs on the surface of erythrocytes with up to near 100% efficiency and allowed targeted delivery of OVs to the lung after intravenous injection to achieve excellent treatment of pulmonary metastases while greatly improving the biocompatibility of OVs as a drug. Polyethyleneimine (PEI) as a bridge to assemble OVs on erythrocytes also played an important role in promoting the transfection of OVs. It is found that ELeOVt approach significantly prolonged the circulation time of OVs and increased the OVs distribution in the lung by more than tenfold, thereby significantly improving the treatment of lung metastases while reducing organ and systemic toxicity. Taken together, these findings suggest that the ELeOVt provides a biocompatible, efficient, and widely available approach to empower OVs to combat lung metastasis.

Genetically engineered probiotics for an optical imaging-guided tumor photothermal therapy/immunotherapy

Bacteria-based cancer therapy (BCT) has been extensively investigated because of the tumor targeting and antitumor immunity activating abilities of bacteria over traditional nanodrugs, but their potential systemic toxicity poses a challenge. Therefore, it is important to visualize the precise localization and real-time distribution of bacteria in vivo to guide the treatment. Herein, biogenetically engineered Escherichia coli Nissle 1917 (EcN) were constructed to highly express tyrosinase to intracellularly generate cyanine 5-labeled melanin-like polymers (Cy5-Mel), thus endowing them with a bright fluorescence and an excellent photothermal performance upon NIR laser irradiation, thereby inducing the intense immunogenic death of tumor cells and release of tumor-associated antigens. Acting as adjuvants, bacteria can greatly stimulate the maturation of dendritic (DC) cells. The in vivo behaviors of these bacteria was monitored via noninvasive optical imaging when they were intravenously administrated to tumor-bearing mice. From this, NIR exposure on tumor sites was carried out at an appropriate time point to induce the damage to tumor cells and for the modulation of tumor immune microenvironments. Thus, via a simple bioengineering strategy, a promising bacteria-based theranostic platform was constructed for tumor treatment.

Nanotechnology Applications in Breast Cancer Immunotherapy

Next-generation cancer treatments are expected not only to target cancer cells but also to simultaneously train immune cells to combat cancer while modulating the immune-suppressive environment of tumors and hosts to ensure a robust and lasting response. Achieving this requires carriers that can codeliver multiple therapeutics to the right cancer and/or immune cells while ensuring patient safety. Nanotechnology holds great potential for addressing these challenges. This article highlights the recent advances in nanoimmunotherapeutic development, with a focus on breast cancer. While immune checkpoint inhibitors (ICIs) have achieved remarkable success and lead to cures in some cancers, their response rate in breast cancer is low. The poor response rate in solid tumors is often associated with the low infiltration of anti-cancer T cells and an immunosuppressive tumor microenvironment (TME). To enhance anti-cancer T-cell responses, nanoparticles are employed to deliver ICIs, bispecific antibodies, cytokines, and agents that induce immunogenic cancer cell death (ICD). Additionally, nanoparticles are used to manipulate various components of the TME, such as immunosuppressive myeloid cells, macrophages, dendritic cells, and fibroblasts to improve T-cell activities. Finally, this article discusses the outlook, challenges, and future directions of nanoimmunotherapeutics.

Enhanced Chemo-Immunotherapy Strategy Utilizing Injectable Thermosensitive Hydrogel for The Treatment of Diffuse Peritoneal Metastasis in Advanced Colorectal Cancer

Patients with colorectal cancer (CRC) and diffuse peritoneal metastasis (PM) are not eligible for surgical intervention. Thus, palliative treatment remains the standard of care in clinical practice. Systemic chemotherapy fails to cause drug accumulation at the lesion sites, while intraperitoneal chemotherapy (IPC) is limited by high clearance rates and associated complications. Given the poor prognosis, a customized OxP/R848@PLEL hydrogel delivery system has been devised to improve the clinical benefit of advanced CRC with diffuse PM. This system is distinguished by its simplicity, security, and efficiency. Specifically, the PLEL hydrogel exhibits excellent injectability and thermosensitivity, enabling the formation of drug depots within the abdominal cavity, rendering it an optimal carrier for IPC. Oxaliplatin (OxP), a first-line drug for advanced CRC, is cytotoxic and enhances the immunogenicity of tumors by inducing immunogenic cell death. Furthermore, OxP and resiquimod (R848) synergistically enhance the maturation of dendritic cells, promote the expansion of cytotoxic T lymphocytes, and induce the formation of central memory T cells. Moreover, R848 domesticates macrophages to an anti-tumor phenotype. OxP/R848@PLEL effectively eradicates peritoneal metastases, completely inhibits ascites production, and significantly prolongs mice lifespan. As such, it provides a promising approach to managing diffuse PM in patients with CRC without surgical indications.

Cellular Membrane Components-Mediated Cancer Immunotherapeutic Platforms

Immune cell engineering is an active field of ongoing research that can be easily applied to nanoscale biomedicine as an alternative to overcoming limitations of nanoparticles. Cell membrane coating and artificial nanovesicle technology have been reported as representative methods with an advantage of good biocompatibility for biomimetic replication of cell membrane characteristics. Cell membrane-mediated biomimetic technique provides properties of natural cell membrane and enables membrane-associated cellular/molecular signaling. Thus, coated nanoparitlces (NPs) and artificial nanovesicles can achieve effective and extended in vivo circulation, enabling execution of target functions. While coated NPs and artificial nanovesicles provide clear advantages, much work remains before clinical application. In this review, first a comprehensive overview of cell membrane coating techniques and artificial nanovesicles is provided. Next, the function and application of various immune cell membrane types are summarized.

Nanotechnology-empowered strategies in treatment of skin cancer

In current scenario skin cancer is a serious condition that has a significant impact on world health. Skin cancer is divided into two categories: melanoma skin cancer (MSC) and non-melanoma skin cancer (NMSC). Because of its significant psychosocial effects and need for significant investment in new technology and therapies, skin cancer is an illness of global health relevance. From the patient's perspective chemotherapy considered to be the most acceptable form of treatment. However, significant negatives of chemotherapy such as severe toxicities and drug resistance pose serious challenges to the treatment. The field of nanomedicine holds significant promise for enhancing the specificity of targeting neoplastic cells through the facilitation of targeted drug delivery to tumour cells. The integration of multiple therapeutic modalities to selectively address cancer-promoting or cell-maintaining pathways constitutes a fundamental aspect of cancer treatment. The use of mono-therapy remains prevalent in the treatment of various types of cancer, it is widely acknowledged in the academic community that this conventional approach is generally considered to be less efficacious compared to the combination treatment strategy. The employment of combination therapy in cancer treatment has become increasingly widespread due to its ability to produce synergistic anticancer effects, mitigate toxicity associated with drugs, and inhibit multi-drug resistance by means of diverse mechanisms. Nanotechnology based combination therapy represents a promising avenue for the development of efficacious therapies for skin cancer within the context of this endeavour. The objective of this article is to provide a description of distinct challenges for efficient delivery of drugs via skin. This article also provides a summary of the various nanotechnology based combinatorial therapy available for skin cancer with their recent advances. This review also focuses on current status of clinical trials of such therapies.

A Dual-Targeting Liposome Enhances Triple-Negative Breast Cancer Chemoimmunotherapy through Inducing Immunogenic Cell Death and Inhibiting STAT3 Activation

Immunotherapy gains increasing focus in treating triple-negative breast cancer (TNBC), while its efficacy is greatly restricted owing to low tumor immunogenicity and immunosuppressive tumor microenvironment (ITM). Herein, a LyP-1 and chondroitin sulfate (CS) dual-modified liposome co-loaded with paclitaxel (PTX) and cryptotanshinone (CTS), namely CS/LyP-1-PC Lip, is engineered for TNBC chemoimmunotherapy via induction of immunogenic cell death (ICD) and inhibition of signal transducer and activator of transcript-3 (STAT3) activation. CS/LyP-1-PC Lip enhances cellular uptake through p32 and CD44 dual receptor-mediated endocytosis. Within the tumor, the CS layer is continuously detached by hyaluronidase to release drugs. Subsequently, CTS sensitizes the cytotoxicity of PTX to 4T1 tumor cells. PTX induces ICD of tumor cells and facilitates infiltration of cytotoxic T lymphocyte to provoke immune response. Meanwhile, the concomitant delivery of CTS inhibits STAT3 activation to decrease infiltration of regulatory T cell, M2-type tumor-associated macrophage, and myeloid-derived suppressor cell, thus reversing ITM. Markedly, the dual-targeting liposome shows superior anti-tumor efficacy in subcutaneous TNBC mice and significant lung metastasis suppression in tumor metastasis model. Overall, this work offers a feasible combination regimen and a promising nanoplatform for the development of TNBC chemoimmunotherapy.

Oxygen-Deficient Bioceramics: Combination of Diagnosis, Therapy, and Regeneration

The journey of ceramics in medicine has been synchronized with an evolution from the first generation-alumina, zirconia, etc.-to the third -3D scaffolds. There is an up-and-coming member called oxygen-deficient or colored bioceramics, which have recently found their way through biomedical applications. The oxygen vacancy steers the light absorption toward visible and near infrared regions, making the colored bioceramics multifunctional-therapeutic, diagnostic, and regenerative. Oxygen-deficient bioceramics are capable of turning light into heat and reactive oxygen species for photothermal and photodynamic therapies, respectively, and concomitantly yield infrared and photoacoustic images. Different types of oxygen-deficient bioceramics have been recently developed through various synthesis routes. Some of them like TiO2- x , MoO3- x , and WOx have been more investigated for biomedical applications, whereas the rest have yet to be scrutinized. The most prominent advantage of these bioceramics over the other biomaterials is their multifunctionality endowed with a change in the microstructure. There are some challenges ahead of this category discussed at the end of the present review. By shedding light on this recently born bioceramics subcategory, it is believed that the field will undergo a big step further as these platforms are naturally multifunctional.

Nanotechnology-Assisted Immunogenic Cell Death for Effective Cancer Immunotherapy

Tumor vaccines have been used to treat cancer. How to efficiently induce tumor-associated antigens (TAAs) secretion with host immune system activation is a key issue in achieving high antitumor immunity. Immunogenic cell death (ICD) is a process in which tumor cells upon an external stimulus change from non-immunogenic to immunogenic, leading to enhanced antitumor immune responses. The immune properties of ICD are damage-associated molecular patterns and TAA secretion, which can further promote dendritic cell maturation and antigen presentation to T cells for adaptive immune response provocation. In this review, we mainly summarize the latest studies focusing on nanotechnology-mediated ICD for effective cancer immunotherapy as well as point out the challenges.

Tumor-Associated Extracellular Microvesicles with Fluorine-Modified Carbohydrate Antigens Trigger a Stronger Antitumor Immune Response

Abnormal glycosylation is a hallmark of tumor development, and tumor-associated carbohydrate antigens are potential immune targets for tumor therapy. Tumor-associated extracellular microvesicles are subcellular vesicles released from cell membranes that have immunogenicity similar to that of precursor cells. However, unmodified tumor-derived microvesicles have weaknesses, such as low immunogenicity, poor biostability, and short half-life in vivo. For the first time, we herein generated extracellular microvesicles containing modified tumor-associated carbohydrate antigens by constructing a cell line with highly expressed antigen-processing enzymes utilizing fluorine-modified monosaccharide substrates via a metabolic oligosaccharide engineering strategy. The microvesicles were applied to tumor immunity, achieving enhanced immunoprophylaxis and immunotherapy effects. Furthermore, the mechanisms of antitumor immunity were explored. Our findings may provide new insights into the adhibition of suitably modified extracellular microvesicles and the development of more effective carbohydrate-based anticancer vaccines.

Impact of Poly(Ester Amide) Structure on Properties and Drug Delivery for Prostate Cancer Therapy

Objective: We aim to develop a polymer library consisting of phenylalanine-based poly(ester amide)s (Phe-PEAs) for cancer therapy and investigate the structure-property relationship of these polymers to understand their impact on the drug delivery efficiency of corresponding nanoparticles (NPs). Impact Statement: Our study provides insights into the structure-property relationship of polymers in NP-based drug delivery applications and offers a potential polymer library and NP platform for enhancing cancer therapy. Introduction: Polymer NP-based drug delivery systems have demonstrated substantial potential in cancer therapy by improving drug efficacy and minimizing systemic toxicity. However, successful design and optimization of these systems require a comprehensive understanding of the relationship between polymer structure and physicochemical properties, which directly influence the drug delivery efficiency of the corresponding NPs. Methods: A series of Phe-PEAs with tunable structures was synthesized by varying the length of the methylene group in the diol part of the polymers. Subsequently, Phe-PEAs were formulated into NPs for doxorubicin (DOX) delivery in prostate cancer therapy. Results: Small adjustments in polymer structure induced the changes in the hydrophobicity and thermal properties of the PEAs, consequently NP size, drug loading capacity, cellular uptake efficacy, and cytotoxicity. Additionally, DOX-loaded Phe-PEA NPs demonstrated enhanced tumor suppression and reduced side effects in prostate tumor-bearing mice. Conclusion: Phe-PEAs, with their finely tunable structures, show great promise as effective and customizable nanocarriers for cancer therapy.

Self-driven nanoprodrug platform with enhanced ferroptosis for synergistic photothermal-IDO immunotherapy

Insufficient immune stimulation and stubborn immune resistance are the critical factors limiting tumor immunotherapy. Here, we report a multifunctional nanoprodrug platform with self-driven indoximod (IND) release and oxidative stress amplification. The aim is to awaken immune responses and block the indoleamine 2,3-dioxygenase (IDO) pathway through a combination of ferroptosis, photothermal therapy, and immunotherapy. This nanosystem improved the delivery efficiency of IND due to click chemistry linked ROS responsive prodrug and self-driven drug release. Meanwhile, the tactic of simultaneously increasing ROS and eliminating GSH amplified oxidative stress and strengthened ferroptosis, which further enhanced immunogenicity along with polydopamine-based photothermal therapy. IDO immunization combined with ferroptosis as well as photothermal therapy not only stimulated immune response, but also reversed immune suppression with enhanced immune memory. Therefore, primary tumor, distant tumor, and cancer metastasis were inhibited. This study provides a perspective on immunotherapeutics for cancer treatment.

Chitosan-g-estrone Nanoparticles of Palbociclib Vanished Hypoxic Breast Tumor after Targeted Delivery: Development and Ultrasound/Photoacoustic Imaging

Breast cancer is the leading cause of death among women globally. Approximately 80% of all breast cancers diagnosed are overexpressed with estrogen receptors (ERs). In this study, we have developed an estrone (Egen)-grafted chitosan-based polymeric nanocarrier for the targeted delivery of palbociclib (PLB) to breast cancer. The nanoparticles (NPs) were prepared by solvent evaporation using the ionic gelation method and characterized for particle size, zeta potential, polydispersity, surface morphology, surface chemistry, drug entrapment efficiency, cytotoxicity assay, cellular uptake, and apoptosis study. The developed PLB-CS NPs and PLB-CS-g-Egen NPs had a particle size of 116.3 ± 1.53 nm and 141.6 ± 1.97 nm, respectively. The zeta potential of PLB-CS NPs and PLB-CS-g-Egen NPs was found to be 18.70 ± 0.416 mV and 12.45 ± 0.574 mV, respectively. The morphological analysis demonstrated that all NPs were spherical in shape and had a smooth surface. An in vitro cytotoxicity assay was performed in estrogen receptor (ER)-expressing MCF7 cells and T47D cells, which suggested that targeted NPs were 57.34- and 30.32-fold more cytotoxic compared to the pure PLB, respectively. Additionally, cell cycle analysis confirmed that cell cycle progression from the G1 into S phase was blocked more efficiently by targeted NPs compared to nontargeted NPs and PLB in MCF7 cells. In vivo pharmacokinetic studies demonstrated that entrapment of the PLB in the NPs improved the half-life and bioavailability by ∼2-3-fold. Further, ultrasound and photoacoustic imaging of DMBA induced breast cancer in the Sprague-Dawley (SD) rat showed that targeted NPs completely vanished breast tumor, reduced hypoxic tumor volume, and suppressed tumor angiogenesis more efficiently compared to the nontargeted NPs and free PLB. Further, in vitro hemocompatibility and histopathology studies suggested that NPs were biocompatible and safe for clinical use.

Lipid-based nanoparticles for cancer immunotherapy

As the fourth most important cancer management strategy except surgery, chemotherapy and radiotherapy, cancer immunotherapy has been confirmed to elicit durable antitumor effects in the clinic by leveraging the patient's own immune system to eradicate the cancer cells. However, the limited population of patients who benefit from the current immunotherapies and the immune related adverse events hinder its development. The immunosuppressive microenvironment is the main cause of the failure, which leads to cancer immune evasion and immunity cycle blockade. Encouragingly, nanotechnology has been engineered to enhance the efficacy and reduce off-target toxicity of their therapeutic cargos by spatiotemporally controlling the biodistribution and release kinetics. Among them, lipid-based nanoparticles are the first nanomedicines to make clinical translation, which are now established platforms for diverse areas. In this perspective, we discuss the available lipid-based nanoparticles in research and market here, then describe their application in cancer immunotherapy, with special emphasis on the T cells-activated and macrophages-targeted delivery system. Through perpetuating each step of cancer immunity cycle, lipid-based nanoparticles can reduce immunosuppression and promote drug delivery to trigger robust antitumor response.

Biomaterials That Induce Immunogenic Cell Death

The immune system takes part in most physiological and pathological processes of the body, including the occurrence and development of cancer. Immunotherapy provides a promising modality for inhibition and even the cure of cancer. During immunotherapy, the immunogenic cell death (ICD) of tumor cells induced by chemotherapy, radiotherapy, phototherapy, bioactive materials, and so forth, triggers a series of cellular responses by causing the release of tumor-associated antigens and damage-associated molecular patterns, which ultimately activate innate and adaptive immune responses. Among them, the ICD-induced biomaterials attract increasing conditions as a benefit of biosafety and multifunctional modifications. This Review summarizes the research progress in biomaterials for inducing ICD via triggering endoplasmic reticulum oxidative stress, mitochondrial dysfunction, and cell membrane rupture and discusses the application prospects of ICD-inducing biomaterials in clinical practice for cancer immunotherapy.

Gold Nanorods and Polymer Micelles Mediated Dual TLR Stimulators Delivery System CPG@Au NRs/M-R848 Regulate Macrophages Reprogramming and DC Maturation for Enhanced Photothermal Immunotherapy of Melanoma

Synergistic photothermal immunotherapy has emerged as a favorable therapeutic approach to fight cancer. However, design of an effective photothermal immunotherapy system to suppress tumor growth and simultaneously inhibit tumor metastases continues to be a challenge. Here a dual toll-like receptor agonists delivery system CPG@Au NRs/m-R848 for combined photothermal immunotherapy of melanoma is developed. CPG@Au NRs/m-R848 displays strong antitumor effects by promoting maturation of dendritic cells (DCs) and reprogramming of M2 macrophages into M1 phenotype. Moreover, immunogenic cell death (ICD) induced by photothermal ablation of Au NRs could synergistically produce in situ vaccination effect with CPG ODN and R848, generating systemic and lasting antitumor immunity. It is further proved that CPG@Au NRs/m-R848 treatment inhibits tumor growth in bilateral B16F10 tumors model by eliciting CD8+ T cell response. Overall, this work suggests that this strategy hold great potential in tumor immunotherapy by regulating tumor-associated macrophage polarization, triggering DCs maturation and inducing ICD.

Nanotechnology-enabled immunogenic cell death for improved cancer immunotherapy

Tumor immunotherapy has revolutionized the field of oncology treatments in recent years. As one of the promising strategies of cancer immunotherapy, tumor immunogenic cell death (ICD) has shown significant potential for tumor therapy. Nanoparticles are widely used for drug delivery due to their versatile characteristics, such as stability, slow blood elimination, and tumor-targeting ability. To increase the specificity of ICD inducers and improve the efficiency of ICD induction, functionally specific nanoparticles, such as liposomes, nanostructured lipid carriers, micelles, nanodiscs, biomembrane-coated nanoparticles and inorganic nanoparticles have been widely reported as the vehicles to deliver ICD inducers in vivo. In this review, we summarized the strategies of different nanoparticles for ICD-induced cancer immunotherapy, and systematically discussed their advantages and disadvantages as well as provided feasible strategies for solving these problems. We believe that this review will offer some insights into the design of effective nanoparticulate systems for the therapeutic delivery of ICD inducers, thus, promoting the development of ICD-mediated cancer immunotherapy.

Supramolecular Polypeptide Self-Assembly Mediated In Situ Elicitation of Robust Innate and Adaptive Immune Responses Boosts Immunogenic Photothermal Therapy toward "Cold" Tumor

As a promising cancer treatment modality that has emerged, photothermal therapy can harness antitumor immunity by triggering immunogenic cell death (ICD) in addition to direct cell ablation. However, the immuno-stimulation induced by PTT alone is insufficient to achieve satisfactory cancer eradication, especially in immunologically "cold" tumors due to their harsh immunosuppressive microenvironment. Effective activation of the innate immune system is indispensable to boost a robust adaptive antitumor immune response typically initiated by dendritic cells (DCs). Herein the above issues are addressed by constructing an environmentally responsive supramolecular nanoself-assembly (PSAs) derived from a novel polypeptide-based block copolymer, which is capable of co-load photothermal immunomodulators efficiently under structure-guided π-π stacking interactions. In the murine model of 4T1 xenograft tumors, the fabricated PSAs with payloads trigger both adaptive and innate immune responses in situ through activation of ICD as well as STING-dependent signal pathway. The findings reveal a new mechanism of harnessing photothermal therapy toward immunologically "cold" tumors.

Nano-drug co-delivery system of natural active ingredients and chemotherapy drugs for cancer treatment: a review

Chemotherapy drugs have been used for a long time in the treatment of cancer, but serious side effects are caused by the inability of the drug to be solely delivered to the tumor when treating cancer with chemotherapy. Natural products have attracted more and more attention due to the antitumor effect in multiple ways, abundant resources and less side effects. Therefore, the combination of natural active ingredients and chemotherapy drugs may be an effective antitumor strategy, which can inhibit the growth of tumor and multidrug resistance, reduce side effects of chemotherapy drugs. Nano-drug co-delivery system (NDCDS) can play an important role in the combination of natural active ingredients and chemotherapy drugs. This review provides a comprehensive summary of the research status and application prospect of nano-delivery strategies for the combination of natural active ingredients and chemotherapy drugs, aiming to provide a basis for the development of anti-tumor drugs.

HSP70-Promoter-Driven CRISPR/Cas9 System Activated by Reactive Oxygen Species for Multifaceted Anticancer Immune Response and Potentiated Immunotherapy

To address the low response rate to immune checkpoint blockade (ICB) therapy, we propose a specific promoter-driven CRISPR/Cas9 system, F-PC/pHCP, that achieves permanent genomic disruption of PD-L1 and elicits a multifaceted anticancer immune response to potentiate immunotherapy. This system consists of a chlorin e6-encapsulated fluorinated dendrimer and HSP70-promoter-driven CRISPR/Cas9. F-PC/pHCP under 660 nm laser activated the HSP70 promoter and enabled the specific expression of the Cas9 protein to disrupt the PD-L1 gene, preventing immune escape. Moreover, F-PC/pHCP also induced immunogenic cell death (ICD) of tumor cells and reprogrammed the immunosuppressive tumor microenvironment. Overall, this specific promoter-driven CRISPR/Cas9 system showed great anticancer efficacy and, more importantly, stimulated an immune memory response to inhibit distant tumor growth and lung metastasis. This CRISPR/Cas9 system represents an alternative strategy for ICB therapy as well as enhanced cancer immunotherapy.

Nano-delivery systems for food bioactive compounds in cancer: prevention, therapy, and clinical applications

Bioactive compounds represent a broad class of dietary metabolites derived from fruits and vegetables, such as polyphenols, carotenoids and glucosinolates with potential for cancer prevention. Curcumin, resveratrol, quercetin, and β-carotene have been the most widely applied bioactive compounds in chemoprevention. Lately, many approaches to encapsulating bioactive components in nano-delivery systems have improved biomolecules' stability and targeted delivery. In this review, we critically analyze nano-delivery systems for bioactive compounds, including polymeric nanoparticles (NPs), solid lipid nanoparticles (SLN), nanostructured lipid carriers (NLC), liposomes, niosomes, and nanoemulsions (NEs) for potential use in cancer therapy. Efficacy studies of the nanoformulations using cancer cell lines and in vivo models and updated human clinical trials are also discussed. Nano-delivery systems were found to improve the therapeutic efficacy of bioactive molecules against various types of cancer (e.g., breast, prostate, colorectal and lung cancer) mainly due to the antiproliferation and pro-apoptotic effects of tumor cells. Furthermore, some bioactive compounds have promised combination therapy with standard chemotherapeutic agents, with increased tumor efficiency and fewer side effects. These opportunities were identified and developed to ensure more excellent safety and efficacy of novel herbal medicines enabling novel insights for designing nano-delivery systems for bioactive compounds applied in clinical cancer therapy.