Exposure Of Damage-associated Molecular Patterns Research Articles

Treatment of Conjunctival Melanoma Cell Lines With a Light-Activated Virus-Like Drug Conjugate Induces Immunogenic Cell Death.

Conjunctival melanoma (CJM) is a rare malignant ocular surface tumor, which often leads to local recurrences and metastases. In murine models of subcutaneous tumors, treatment with a novel virus-like drug conjugate (VDC; Bel-sar) showed a dual mechanism of action with direct tumor cell killing as well as stimulation of an antitumoral immune response. Bel-sar is currently being evaluated for the treatment of primary uveal melanoma and indeterminate nevi in a phase III clinical trial. We determined whether Bel-sar also has direct antitumor efficiency and a potential immunostimulatory capacity in CJM cells. Three human tumor-derived CJM lines were used. Bel-sar's subcellular and intracellular locations were determined with tracers. Following light activation of Bel-sar, cytotoxicity and exposure of damage-associated molecular patterns (DAMPs) were assessed. Treated tumor cells were co-cultured with THP-1 derived macrophages to assess tumor-cell phagocytosis. Bel-sar was bound and internalized by CJM cells and subsequently found in the cell membrane, lysosome, Golgi apparatus, and mitochondria. Bel-sar activation induced near complete cell death with half-maximal inhibitory concentration (IC50) values between 30 pM and 60 pM. Finally, light-activated Bel-sar enhanced exposure of DAMPs, including calreticulin, heat shock protein 90, and stimulated phagocytosis by macrophages. Treatment with a novel VDC (Bel-sar) induced pro-immunogenic cell death in all three CJM cell lines. The in vitro cytotoxicity was accompanied by exposure of DAMPs, suggesting Bel-sar is a potential treatment for CJM by a dual mechanism of action. This dual mechanism may provide a targeted and direct killing of tumor cells and induce an immune response which might decrease local recurrences and metastasis.

Doxorubicin-induced Immunogenic Cell Death Impairs Tumor Progression and Distant Metastasis in a 4T1 Breast Cancer Tumor Model.

Cancer is an individual disease and its formation and development are specific to each host. Conventional treatments are ineffective in complex cases, such as metastasis, and have severe adverse side effects. New strategies are needed to address the problem, and the use of immunogenic cell death (ICD) as a trigger or booster of the immune system through the exposure of damage-associated molecular patterns, along with tumor antigens, by cancerous cells is presented as an immunization approach in this work. For this purpose, 4T1 cells were exposed to doxorubicin (DOX) for 24 hours and then, these cells undergoing ICD were subcutaneously administered to mice. The ICD induction by DOX on 4T1 was assessed by flow cytometry and image analysis. This immunization process was performed three times and after the last administration, the immunized mice were challenged with a subcutaneous xenograft of live cancer cells. The results demonstrate that the mice immunized with cells undergoing ICD after exposure to DOX presented no primary tumor or indications of distant metastatic lesion development. In summary, our findings indicate that the immunization process utilizing ICD is indeed efficacious in managing this aggressive form of pre-clinical breast cancer.

The Potential of Photodynamic Therapy Using Solid Lipid Nanoparticles with Aluminum Phthalocyanine Chloride as a Nanocarrier for Modulating Immunogenic Cell Death in Murine Melanoma In Vitro.

Photodynamic therapy (PDT) uses a photosensitizer to generate reactive oxygen species (ROS) that kill target cells. In cancer treatments, PDT can potentially induce immunogenic cell death (ICD), which is characterized by a well-controlled exposure of damage-associated molecular patterns (DAMPs) that activate dendritic cells (DCs) and consequently modulate the immune response in the tumor microenvironment. However, PDT still has limitations, such as the activity of photosensitizers in aqueous media and poor bioavailability. Therefore, a new photosensitizer system, SLN-AlPc, has been developed to improve the therapeutic efficacy of PDT. In vitro experiments showed that the light-excited nanocarrier increased ROS production in murine melanoma B16-F10 cells and modulated the profile of DCs. PDT induced cell death accompanied by the exposure of DAMPs and the formation of autophagosomes. In addition, the DCs exposed to PDT-treated B16-F10 cells exhibited morphological changes, increased expression of MHCII, CD86, CD80, and production of IL-12 and IFN-γ, suggesting immune activation towards an antitumor profile. These results indicate that the SLNs-AlPc protocol has the potential to improve PDT efficacy by inducing ICD and activating DCs.

Tumor Pigmentation Does Not Affect Light-Activated Belzupacap Sarotalocan Treatment but Influences Macrophage Polarization in a Murine Melanoma Model.

Pigmentation in uveal melanoma is associated with increased malignancy and is known as a barrier for photodynamic therapy. We investigated the role of pigmentation in tumor behavior and the response to light-activated Belzupacap sarotalocan (Bel-sar) treatment in a pigmented (wild type) and nonpigmented (tyrosinase knock-out [TYR knock-out]) cell line in vitro and in a murine model. The B16F10 (TYR knock-out) was developed using CRISPR/Cas9. After the treatment with light-activated Bel-sar, cytotoxicity and exposure of damage-associated molecular patterns (DAMPs) were measured by flow cytometry. Treated tumor cells were co-cultured with bone marrow-derived macrophages (BMDMs) and dendritic cells (DCs) to assess phagocytosis and activation. Both cell lines were injected subcutaneously in syngeneic C57BL/6 mice. Knock-out of the tyrosinase gene in B16F10 led to loss of pigmentation and immature melanosomes. Pigmented tumors contained more M1 and fewer M2 macrophages compared with amelanotic tumors. Bel-sar treatment induced near complete cell death, accompanied with enhanced exposure of DAMPs in both cell lines, resulting in enhanced phagocytosis of BMDMs and maturation of DCs. Bel-sar treatment induced a shift to M1 macrophages and delayed tumor growth in both in vivo tumor models. Following treatment, especially the pigmented tumors and their draining lymph nodes contained IFN-gamma positive CD8+T cells. Pigmentation influenced the type of infiltrating macrophages in the tumor, with more M1 macrophages in pigmented tumors. Belzupacap sarotalocan treatment induced immunogenic cell death and tumor growth delay in pigmented as well as in nonpigmented models and stimulated M1 macrophage influx in both models.

Nanozyme-mediated biocatalysis as a mitochondrial oxidative stress amplifier for tumor nanocatalytic immunotherapy

Nanozyme-mediated tumor catalytic therapy has recently garnered attention as a means of destroying tumor cells and eliciting anti-tumor immune responses. Herein, a copper-doped mesoporous polydopamine (CP) nanozyme modified with triphenylphosphine (TPP) and hyaluronic acid (HA) was designed as a mitochondrial oxidative stress amplifier (CPTH) for inducing apoptosis and promoting immune responses with the assistance of mild photothermal therapy. The density functional theory (DFT) revealed the superoxide dismutase-like reaction mechanism of nanozymes, and combined with 3-amino-1,2,4-triazole (AT, catalase inhibitor) to achieve the goal of increasing the source and reducing the off-target consumption of intra-mitochondrial H2O2. Meanwhile, CPTH-AT nanozyme was found to amplify mitochondrial oxidative stress by inducing powerful oxidative OH through intra-mitochondrial GSH consumption and exerting peroxidase-like activity. The induction of mitochondrial oxidative damage serves as a trigger for the release of tumor-associated antigens. Thus, CPTH-AT nanozyme combined with mild photothermal therapy caused substantial exposure of damage-associated molecular patterns, maximizing the incidence of tumor immunogenic cell death. Moreover, nanozymes further promoted the dendritic cells maturation and recruitment, increased the infiltration of cytotoxic T lymphocytes and helper T cells, and decreased the proportion of regulatory T cells. In brief, the mitochondria-targeted nanozyme-based biocatalytic immunotherapy combined with mild photothermal therapy represents a promising cancer therapeutic strategy, establishing new paradigms for improving the bio-applications of nanozymes.

A single photodynamic priming protocol augments delivery of ⍺-PD-L1 mAbs and induces immunogenic cell death in head and neck tumors.

Photodynamic priming (PDP) leverages the photobiological effects of subtherapeutic photodynamic therapy (PDT) regimens to modulate the tumor vasculature and stroma. PDP also sensitizes tumors to secondary therapies, such as immunotherapy by inducing a cascade of molecular events, including immunogenic cell death (ICD). We and others have shown that PDP improves the delivery of antibodies, among other theranostic agents. However, it is not known whether a single PDP protocol is capable of both inducing ICD in vivo and augmenting the delivery of immune checkpoint inhibitors. In this rapid communication, we show for the first time that a single PDP protocol using liposomal benzoporphyrin derivative (Lipo-BPD, 0.25 mg/kg) with 690 nm light (75 J/cm2 , 100 mW/cm2 ) simultaneously doubles the delivery of ⍺-PD-L1 antibodies in murine AT-84 head and neck tumors and induces ICD in vivo. ICD was observed as a 3-11 fold increase in tumor cell exposure of damage-associated molecular patterns (Calreticulin, HMGB1, and HSP70). These findings suggest that this single, highly translatable PDP protocol using clinically relevant Lipo-BPD holds potential for improving immunotherapy outcomes in head and neck cancer. It can do so by simultaneously overcoming physical barriers to the delivery of immune checkpoint inhibitors, and biochemical barriers that contribute to immunosuppression.

In Vitro Testing of the Virus-Like Drug Conjugate Belzupacap Sarotalocan (AU-011) on Uveal Melanoma Suggests BAP1-Related Immunostimulatory Capacity.

The virus-like drug conjugate belzupacap sarotalocan (AU-011), currently under clinical investigation for first-line treatment of primary uveal melanoma (UM), shows enhanced tumor specificity by targeting heparan sulfate proteoglycans (HSPG). Such a treatment may potentially lead to systemic immune responses. We studied the potential of AU-011 treatment to induce immunogenic cell death as the first step to induce systemic immunity. We determined binding and uptake of AU-011 in ten primary and metastatic UM cell lines. The subcellular location of AU-011 was assessed by fluorescence microscopy. Following light activation (wavelength 690 nm) of AU-011, the half-maximal effective concentration (EC50) of AU-011 treatment and exposure of damage-associated molecular patterns (DAMPs) were assessed using flow cytometry. DAMPs were measured by RNAseq. Fluorescence microscopy revealed most of the AU-011 was present in the cytoplasm. AU-011 binding and uptake by UM cells increased over time, with a lower uptake in BAP1-negative than in BAP1-positive cell lines. AU-011 activation induced cell death across all UM cell lines with EC50 values at picomolar concentrations. The AU-011 concentration and total light dose (J/cm2) were the most important parameters for the observed cytotoxicity. Finally, light-activated AU-011 induced exposure of DAMPs calreticulin (CRT) and HSP90. CRT exposure by light-activated AU-011 as well as CRT RNA exposure were lower in BAP1-negative compared to BAP1-positive UM cell lines. AU-011 treatment at low picomolar range induces immunogenic cell death in all 10 UM cell lines. The in vitro cytotoxicity was accompanied by exposure of DAMPs (HSP90 and CRT), suggesting AU-011 may contribute to the development of systemic immunity and be a suitable candidate for combination with immunotherapy in vivo. AU-011 treatment was more effective against BAP1-positive cell lines, with a lower EC50 and higher CRT exposure.

Phase-transition nanodroplets with immunomodulatory capabilities for potentiating mild magnetic hyperthermia to inhibit tumour proliferation and metastasis

BackgroundMagnetic hyperthermia (MHT)-mediated thermal ablation therapy has promising clinical applications in destroying primary tumours. However, traditional MHT still presents the challenges of damage to normal tissues adjacent to the treatment site and the destruction of tumour-associated antigens due to its high onset temperature (> 50 °C). In addition, local thermal ablation of tumours often exhibits limited therapeutic inhibition of tumour metastasis.ResultsTo address the above defects, a hybrid nanosystem (SPIOs + RPPs) was constructed in which phase transition nanodroplets with immunomodulatory capabilities were used to potentiate supermagnetic iron oxide nanoparticle (SPIO)-mediated mild MHT (< 44 °C) and further inhibit tumour proliferation and metastasis. Magnetic-thermal sensitive phase-transition nanodroplets (RPPs) were fabricated from the immune adjuvant resiquimod (R848) and the phase transition agent perfluoropentane (PFP) encapsulated in a PLGA shell. Because of the cavitation effect of microbubbles produced by RPPs, the temperature threshold of MHT could be lowered from 50℃ to approximately 44℃ with a comparable effect, enhancing the release and exposure of damage-associated molecular patterns (DAMPs). The exposure of calreticulin (CRT) on the cell membrane increased by 72.39%, and the released high-mobility group B1 (HMGB1) increased by 45.84% in vivo. Moreover, the maturation rate of dendritic cells (DCs) increased from 4.17 to 61.33%, and the infiltration of cytotoxic T lymphocytes (CTLs) increased from 10.44 to 35.68%. Under the dual action of mild MHT and immune stimulation, contralateral and lung metastasis could be significantly inhibited after treatment with the hybrid nanosystem.ConclusionOur work provides a novel strategy for enhanced mild magnetic hyperthermia immunotherapy and ultrasound imaging with great clinical translation potential.

The Blockade of Mitogen-Activated Protein Kinase 14 Activation by Marine Natural Product Crassolide Triggers ICD in Tumor Cells and Stimulates Anti-Tumor Immunity

Immunogenic cell death (ICD) refers to a type of cell death that stimulates immune responses. It is characterized by the surface exposure of damage-associated molecular patterns (DAMPs), which can facilitate the uptake of antigens by dendritic cells (DCs) and stimulate DC activation, resulting in T cell immunity. The activation of immune responses through ICD has been proposed as a promising approach for cancer immunotherapy. The marine natural product crassolide, a cembranolide isolated from the Formosan soft coral Lobophytum michaelae, has been shown to have cytotoxic effects on cancer cells. In this study, we investigated the effects of crassolide on the induction of ICD, the expression of immune checkpoint molecules and cell adhesion molecules, as well as tumor growth in a murine 4T1 mammary carcinoma model. Immunofluorescence staining for DAMP ectolocalization, Western blotting for protein expression and Z'-LYTE kinase assay for kinase activity were performed. The results showed that crassolide significantly increased ICD and slightly decreased the expression level of CD24 on the surface of murine mammary carcinoma cells. An orthotopic tumor engraftment of 4T1 carcinoma cells indicated that crassolide-treated tumor cell lysates stimulate anti-tumor immunity against tumor growth. Crassolide was also found to be a blocker of mitogen-activated protein kinase 14 activation. This study highlights the immunotherapeutic effects of crassolide on the activation of anticancer immune responses and suggests the potential clinical use of crassolide as a novel treatment for breast cancer.

Immune checkpoint inhibition combined with targeted therapy using a novel virus-like drug conjugate induces complete responses in a murine model of local and distant tumors

Metastases remain the leading cause of cancer-related death worldwide. Therefore, improving the treatment efficacy against such tumors is essential to enhance patient survival. AU-011 (belzupacap sarotalocan) is a new virus-like drug conjugate which is currently in clinical development for the treatment of small choroidal melanoma and high-risk indeterminate lesions in the eye. Upon light activation, AU-011 induces rapid necrotic cell death which is pro-inflammatory and pro-immunogenic, resulting in an anti-tumor immune response. As AU-011 is known to induce systemic anti-tumor immune responses, we investigated whether this combination therapy would also be effective against distant, untreated tumors, as a model for treating local and distant tumors by abscopal immune effects. We compared the efficacy of combining AU-011 with several different checkpoint blockade antibodies to identify optimal treatment regimens in an in vivo tumor model. We show that AU-011 induces immunogenic cell death through the release and exposure of damage-associated molecular patterns (DAMPs), resulting in the maturation of dendritic cells in vitro. Furthermore, we show that AU-011 accumulates in MC38 tumors over time and that ICI enhances the efficacy of AU-011 against established tumors in mice, resulting in complete responses for specific combinations in all treated animals bearing a single MC38 tumor. Finally, we show that AU-011 and anti-PD-L1/anti-LAG-3 antibody treatment was an optimal combination in an abscopal model, inducing complete responses in approximately 75% of animals. Our data show the feasibility of combining AU-011 with PD-L1 and LAG-3 antibodies for the treatment of primary and distant tumors.

Current Challenges and Opportunities of Photodynamic Therapy against Cancer.

Photodynamic therapy (PDT) is an established, minimally invasive treatment for specific types of cancer. During PDT, reactive oxygen species (ROS) are generated that ultimately induce cell death and disruption of the tumor area. Moreover, PDT can result in damage to the tumor vasculature and induce the release and/or exposure of damage-associated molecular patterns (DAMPs) that may initiate an antitumor immune response. However, there are currently several challenges of PDT that limit its widespread application for certain indications in the clinic. A literature study was conducted to comprehensively discuss these challenges and to identify opportunities for improvement. The most notable challenges of PDT and opportunities to improve them have been identified and discussed. The recent efforts to improve the current challenges of PDT are promising, most notably those that focus on enhancing immune responses initiated by the treatment. The application of these improvements has the potential to enhance the antitumor efficacy of PDT, thereby broadening its potential application in the clinic.

Calpains Released from Necrotic Tumor Cells Enhance Antigen Cross-Presentation to Activate CD8+ T Cells In Vitro

The initiation of CD8+ T cell responses against dead cell-associated Ags is tightly regulated, facilitating adaptive immunity against pathogens and tumors while preventing autoimmunity. It is now well established that dying cells actively regulate the generation of CD8+ T cell responses via the release or exposure of damage-associated molecular patterns. However, it is unclear whether nonproteasomal proteases (activated in stressed and dying cells) can influence the availability of Ags for cross-presentation. Using a mouse model of immunogenic necrosis, we investigated the role of tumor-derived proteases in the priming of CD8+ T cells. We demonstrate that proteases released from necrotic tumor cells can degrade whole-protein Ag, generating proteolytic intermediates that are efficiently cross-presented by dendritic cells and enhance CD8+ T cell cross-priming. We identify a dominant role for calpain proteases, which are activated during necrotic cell death induced by severe heat shock. Mechanistically, proteolytic intermediates generated by tumor-derived proteases associate with necrotic tumor cell debris, which acts as a vehicle for Ag transfer that facilitates highly efficient cross-presentation in dendritic cells. Our results suggest that proteolytic systems activated in Ag donor cells during cell death may influence the availability of antigenic substrates for cross-presentation, thereby regulating the antigenicity of cell death.

Examination of the role of necroptotic damage-associated molecular patterns in tissue fibrosis.

Fibrosis is defined as the abnormal and excessive deposition of extracellular matrix (ECM) components, which leads to tissue or organ dysfunction and failure. However, the pathological mechanisms underlying fibrosis remain unclear. The inflammatory response induced by tissue injury is closely associated with tissue fibrosis. Recently, an increasing number of studies have linked necroptosis to inflammation and fibrosis. Necroptosis is a type of preprogrammed death caused by death receptors, interferons, Toll-like receptors, intracellular RNA and DNA sensors, and other mediators. These activate receptor-interacting protein kinase (RIPK) 1, which recruits and phosphorylates RIPK3. RIPK3 then phosphorylates a mixed lineage kinase domain-like protein and causes its oligomerization, leading to rapid plasma membrane permeabilization, the release of cellular contents, and exposure of damage-associated molecular patterns (DAMPs). DAMPs, as inflammatory mediators, are involved in the loss of balance between extensive inflammation and tissue regeneration, leading to remodeling, the hallmark of fibrosis. In this review, we discuss the role of necroptotic DAMPs in tissue fibrosis and highlight the inflammatory responses induced by DAMPs in tissue ECM remodeling. By summarizing the existing literature on this topic, we underscore the gaps in the current research, providing a framework for future investigations into the relationship among necroptosis, DAMPs, and fibrosis, as well as a reference for later transformation into clinical treatment.

An Overview on Immunogenic Cell Death in Cancer Biology and Therapy.

Immunogenic cell death (ICD) is a modality of regulated cell death that is sufficient to promote an adaptive immune response against antigens of the dying cell in an immunocompetent host. An important characteristic of ICD is the release and exposure of damage-associated molecular patterns, which are potent endogenous immune adjuvants. As the induction of ICD can be achieved with conventional cytotoxic agents, it represents a potential approach for the immunotherapy of cancer. Here, different aspects of ICD in cancer biology and treatment are reviewed.

A novel virus-like drug conjugate (VDC) in combination with immune checkpoint inhibitors for the treatment of primary tumors and distant metastasis.

e14544 Background: Although there has been great progress in the early diagnosis of choroidal melanoma, metastases remain the leading cause of cancer-related death. Therefore, improving the treatment efficacy against metastases is essential to enhance patient survival. A new targeted therapy, the virus-like drug conjugate (VDC) AU-011 (belzupacap sarotalocan), is currently in clinical development to treat early-stage choroidal melanoma with an intra-ocular administration followed by near-infrared (NIR) light activation using a photodynamic therapy (PDT) laser. Murine experiments have shown that AU-011 enhances immune checkpoint inhibition (ICI) and protects against tumor rechallenge. Methods: We investigated whether this combination therapy had an effect not only on primary tumors but also on distant, untreated tumors, as a model for treating metastatic cancer by abscopal immune effects and compared the efficacy of combining AU-011 with several ICI antibodies. Results: In vitro, AU-011 treatment induced a preferential cytotoxicity in cancer over antigen presenting cells, confirming the tumor-targeting of AU-011. AU-011 treatment induced immunogenic cell death in several murine cancer cell lines through the release and exposure of damage-associated molecular patterns (DAMPs), resulting in the maturation of dendritic cells. Furthermore, AU-011 in combination with ICI antibodies demonstrated greater efficacy than AU-011 alone, or ICI antibodies alone against established MC38 tumors in mice, resulting in complete tumor response in all treated animals for specific combinations. Finally, AU-011 and anti-PD-L1/ anti-LAG-3 antibody treatment was an optimal combination in an abscopal model of metastatic disease, inducing complete cures in approximately 75 % of animals. Conclusions: Based on our observations, we conclude that AU-011 treatment combined with immune checkpoint inhibition is effective against both primary tumors and distant metastases, and identify anti-PD-L1/ anti-LAG-3 as the most potent combination with AU-011. These data may support an investigation of AU-011 in this combination in future clinical trials.[Table: see text]

Perturbation-Based Modeling Unveils the Autophagic Modulation of Chemosensitivity and Immunogenicity in Breast Cancer Cells.

In the absence of new therapeutic strategies, chemotherapeutic drugs are the most widely used strategy against metastatic breast cancer, in spite of eliciting multiple adverse effects and having low responses with an average 5-year patient survival rate. Among the new therapeutic targets that are currently in clinical trials, here, we addressed the association between the regulation of the metabolic process of autophagy and the exposure of damage-associated molecular patterns associated (DAMPs) to immunogenic cell death (ICD), which has not been previously studied. After validating an mCHR-GFP tandem LC3 sensor capacity to report dynamic changes of the autophagic metabolic flux in response to external stimuli and demonstrating that both basal autophagy levels and response to diverse autophagy regulators fluctuate among different cell lines, we explored the interaction between autophagy modulators and chemotherapeutic agents in regards of cytotoxicity and ICD using three different breast cancer cell lines. Since these interactions are very complex and variable throughout different cell lines, we designed a perturbation-based model in which we propose specific modes of action of chemotherapeutic agents on the autophagic flux and the corresponding strategies of modulation to enhance the response to chemotherapy. Our results point towards a promising therapeutic potential of the metabolic regulation of autophagy to overcome chemotherapy resistance by eliciting ICD.

Combining Mechanical High-Intensity Focused Ultrasound Ablation with Chemotherapy for Augmentation of Anticancer Immune Responses.

As a noninvasive therapy, high-intensity focused ultrasound (HIFU) shows great potential in inducing anticancer immune responses. However, the overall anticancer efficacy of HIFU is still limited due to the rapid attenuation of ultrasound waves and inadequacy of ultrasound waves to spread to the whole tumor. Here, we combined HIFU with the ultrasound contrast agent/chemotherapeutic drug co-delivery nanodroplets to achieve synergistic enhancement of anticancer efficacy. Different from the widely used thermal HIFU irradiation, by which excessive heating would result in inactivation of immune stimulatory molecules, we used short acoustic pulses to trigger HIFU (mechanical HIFU, mHIFU) to improve anticancer immune responses. The nanodroplets displayed a mHIFU/glutathione (GSH)-dual responsive drug release property, and their cellular uptake efficacy and toxicity against cancer cells increased upon mHIFU irradiation. The generated immunogenic debris successfully induced the exposure of damage-associated molecular patterns on the cell surface for dendritic cells (DCs) maturation. In vivo experiments with tumor-bearing mice showed that the co-delivery nanodroplets in combination with mHIFU could effectively inhibit tumor growth by inducing immunogenic cell death, activating DCs maturation, and enhancing the effector T-cell infiltration within tumors. This work reveals that combined treatment with nanodroplets and mHIFU is a promising approach to eradicate tumors.

Ferroptosis-apoptosis combined anti-melanoma immunotherapy with a NIR-responsive upconverting mSiO2 photodynamic platform

Photodynamic therapy (PDT) is an appealing treatment for oncologic skin diseases owing to its high spatiotemporally selectivity and non-invasive features. However, its application in melanoma has been restricted by limited penetration depth of ultraviolet (UV)-visible (vis) light, melanin-optical filtration and weak immunogenicity. To circumvent the incomplete tumor damage and insufficient anti-tumor immunity, we prepared a mesoporous coated upconverting nanoparticles (NaYF4:Yb,Er@NaYF4@mSiO2@lipsome)-based platform by co-loading chlorin e6 (Ce6) and buthionine sulfoximine (BSO). This platform converts near-infrared (NIR) light to UV-vis light which enables the destruction of deeply seated nidus, amplification of ferroptotic and apoptotic cell death, as well as an increase in the anti-tumor immunity. Under NIR laser irradiation, NaYF4:Yb,Er@NaYF4@mSiO2@lipsome nanoparticles embedded with Ce6 were designed to ease burden in tumor sites via elevating levels of hydroxyl radicals and the induction of apoptosis. Meanwhile, glutathione depletion was induced through BSO co-administration and direct thiol oxidation, followed by the inactivation of lipid peroxide repair enzyme and initiation of ferroptosis. This combinational strategy resulted in an amplification in intratumoral oxidative stress, which was accompanied with the strong cytotoxicity in vitro and in vivo. The aggravated anti-tumor performance then brought about the exposure of damage-associated molecular patterns, followed by promoted maturation of dendritic cells and effector function of tumor-infiltrating lymphocytes. Taken together, this ferroptosis-apoptosis combined photodynamic strategy provides insights in designing nanomedicines for immunotherapy in melanoma.

Immunogenic cell death in cancer therapy: Present and emerging inducers.

In the tumour microenvironment (TME), immunogenic cell death (ICD) plays a major role in stimulating the dysfunctional antitumour immune system. Chronic exposure of damage‐associated molecular patterns (DAMPs) attracts receptors and ligands on dendritic cells (DCs) and activates immature DCs to transition to a mature phenotype, which promotes the processing of phagocytic cargo in DCs and accelerates the engulfment of antigenic components by DCs. Consequently, via antigen presentation, DCs stimulate specific T cell responses that kill more cancer cells. The induction of ICD eventually results in long‐lasting protective antitumour immunity. Through the exploration of ICD inducers, recent studies have shown that there are many novel modalities with the ability to induce immunogenic cancer cell death. In this review, we mainly discussed and summarized the emerging methods for inducing immunogenic cancer cell death. Concepts and molecular mechanisms relevant to antitumour effects of ICD are also briefly discussed.

Targeted APC Activation in Cancer Immunotherapy to Enhance the Abscopal Effect.

In oncology, the “abscopal effect” refers to the therapeutic effect on a distant tumor resulting from the treatment of local tumor (e. g., ablation, injection, or radiation). Typically associated with radiation, the abscopal effect is thought to be mediated by a systemic antitumor immune response that is induced by two concurrent changes at the treated tumor: (1) the release of tumor antigens and (2) the exposure of damage-associated molecular patterns. Therapies that produce these changes are associated with immunogenic cell death (ICD). Some interventions have been shown to cause an abscopal effect without inducing the release of tumor antigens, suggesting that release of tumor antigens at baseline plays a significant role in mediating the abscopal effect. With tumor antigens already present, therapies that target activation of APCs alone may be sufficient to enhance the abscopal effect. Here, we discuss two therapies targeted at APC activation, TLR9 and CD40 agonists, and their use in the clinic to enhance the abscopal effect.