Photoimmunotherapy Research Articles

The fusion of light and immunity: Advancements in photoimmunotherapy for melanoma.

Metastatic melanoma is an aggressive skin cancer with high mortality and recurrence rates. Despite the clinical success of recent immunotherapy approaches, prevailing resistance rates necessitate the continued development of novel therapeutic options. Photoimmunotherapy (PIT) is emerging as a promising immunotherapy strategy that uses photodynamic therapy (PDT) to unleash systemic immune responses against tumor sites while maintaining the superior tumor-specificity and minimally invasive nature of traditional PDT. In this review, we discuss recent advances in PIT and strategies for the management of melanoma using PIT. PIT can strongly induce immunogenic cell death, inviting the concomitant application of immune checkpoint blockade or adoptive cell therapies. PIT can also be leveraged to selectively remove the suppressive immune populations associated with immunotherapy resistance. The modular nature of PIT therapy design combined with the potential for patient-specific antigen selection or drug co-delivery makes PIT an alluring option for future personalized melanoma care.

Sterically Twisted Mitochondria‐Targeting Photosensitizers for Augmented Near‐Infrared II Fluorescence‐Guided Photodynamic Immunotherapy

AbstractNear‐infrared (NIR) fluorescent mitochondria‐targeting photosensitizers (PSs) hold great potential for efficient image‐guided cancer phototherapy, but it remains challenging to develop PSs concurrently integrating high‐contrast NIR‐II fluorescence imaging and efficient therapeutic capabilities. Herein, a heptamethine cyanine (HCy) PS (termed I2HCy‐TPE nanoparticles (NPs)) by a molecular engineering strategy combining the heavy atom effect and structural distortion is reported. The heavy atom iodine is introduced to boost the intersystem crossing process, and the bulky tetraphenylethylene (TPE) moiety placed at the meso‐position of the heptamethine chain creates a highly distorted conformation in I2HCy‐TPE, theoretically verified by density functional theory calculations. This strategy synergistically promotes the 1O2 generation efficiency and assure the strong NIR fluorescence emission in aggregated states. Combining with the intrinsic mitochondria‐targeting capability, I2HCy‐TPE NPs are able to cause mitochondria‐targeted damage of cancer cells via the PDT and immunogenetic cell death‐triggered immune responses under NIR laser irradiation. In vivo experiments demonstrate that the biocompatible I2HCy‐TPE NPs present exceptional capability for in vivo NIR‐II fluorescence bioimaging of whole‐body and blood vessels, and exert efficient NIR‐II fluorescence‐guided photodynamic immunotherapy against triple‐negative breast cancer.

A thermoresponsive nanocomposite integrates NIR-II-absorbing small molecule with lonidamine for pyroptosis-promoted synergistic immunotherapy

Photothermal immunotherapy is regarded as the ideal cancer therapeutic modality to against malignant solid tumors; however, its therapeutic benefits are often modest and require improvement. In this study, a thermoresponsive nanoparticle (BTN@LND) composed of a photothermal agent (PTA) and pyroptosis inducer (lonidamine) were developed to enhance immunotherapy applications. Specifically, our “two-step” donor engineering strategy produced the strong NIR-II-absorbing organic small-molecule PTA (BTN) that exhibited high NIR-II photothermal performance (ε1064 = 1.51 × 104 M−1 cm−1, η = 75.8%), and this facilitates the diagnosis and treatment of deep tumor tissue. Moreover, the fabricated thermally responsive lipid nanoplatform based on BTN efficiently delivered lonidamine to the tumor site and achieved spatiotemporal release triggered by the NIR-II photothermal effect. In vitro and in vivo experiments demonstrated that the NIR-II photothermal therapy (PTT)-mediated on-demand release of cargo effectively faciliated tumor cell pyroptosis, thereby intensifying the immunogenic cell death (ICD) process to promote antitumor immunotherapy. As a result, this intelligent component bearing photothermal and chemotherapy can maximally suppress the growth of tumors, thus providing a promising approach for pyroptosis/NIR-II PTT synergistic therapy against tumors.Graphical

Activable Nano‐Immunomodulator Assembled from π‐Extended Naphthalenediimide for Precision Photothermal Immunotherapy

A nano‐immunomodulator (R‐NPT NP) comprising a tumor microenvironment (TME) activable resiquimod (R848) and a π‐extended NIR‐absorbing naphthophenanthrolinetetraone (NPT) has been engineered for spatiotemporal controlled photothermal immunotherapy. R‐NPT NP demonstrated excellent photostability, while R848 promoted synergistic immunity as a toll‐like receptor 7/8 (TLR7/8) agonist. Upon accumulation at the tumor site, R‐NPT NP released R848 in response to redox metabolite glutathione (GSH), triggering dendritic cell (DC) activation. The photothermal effect endowed by R‐NPT NP can ablate tumors directly and trigger immunogenic cell death to augment immunity after photoirradiation. The synergistic effect of GSH‐liable TLR7/8 agonist and released immunogenic factors leads to a robust evocation of systematic immunity through promoted DC maturation and T cell infiltration. Thus, R‐NPT NP with photoirradiation achieved 99.3% and 98.2% growth inhibition against primary and distal tumors, respectively.

Activable Nano-Immunomodulator Assembled from π-Extended Naphthalenediimide for Precision Photothermal Immunotherapy.

A nano-immunomodulator (R-NPT NP) comprising a tumor microenvironment (TME) activable resiquimod (R848) and a π-extended NIR-absorbing naphthophenanthrolinetetraone (NPT) has been engineered for spatiotemporal controlled photothermal immunotherapy. R-NPT NP demonstrated excellent photostability, while R848 promoted synergistic immunity as a toll-like receptor 7/8 (TLR7/8) agonist. Upon accumulation at the tumor site, R-NPT NP released R848 in response to redox metabolite glutathione (GSH), triggering dendritic cell (DC) activation. The photothermal effect endowed by R-NPT NP can ablate tumors directly and trigger immunogenic cell death to augment immunity after photoirradiation. The synergistic effect of GSH-liable TLR7/8 agonist and released immunogenic factors leads to a robust evocation of systematic immunity through promoted DC maturation and T cell infiltration. Thus, R-NPT NP with photoirradiation achieved 99.3% and 98.2% growth inhibition against primary and distal tumors, respectively.

Cell surface patching via CXCR4-targeted nanothreads for cancer metastasis inhibition

The binding of therapeutic antagonists to their receptors often fail to translate into adequate manipulation of downstream pathways. To fix this ‘bug’, here we report a strategy that stitches cell surface ‘patches’ to promote receptor clustering, thereby synchronizing subsequent mechano-transduction. The “patches” are sewn with two interactable nanothreads. In sequence, Nanothread-1 strings together adjacent receptors while presenting decoy receptors. Nanothread-2 then targets these decoys multivalently, intertwining with Nanothread-1 into a coiled-coil supramolecular network. This stepwise actuation clusters an extensive vicinity of receptors, integrating mechano-transduction to disrupt signal transmission. When applied to antagonize chemokine receptors CXCR4 expressed in metastatic breast cancer of female mice, this strategy elicits and consolidates multiple events, including interception of metastatic cascade, reversal of immunosuppression, and potentiation of photodynamic immunotherapy, reducing the metastatic burden. Collectively, our work provides a generalizable tool to spatially rearrange cell-surface receptors to improve therapeutic outcomes.

Abstract 1415: Reduction in photoimmunotherapy-induced edema with COX-2 inhibition: Combatting clinically relevant adverse events without compromising efficacy

Abstract ASP-1929 photoimmunotherapy (PIT), an investigational drug-device combination, consists of an epithelial growth factor receptor (EGFR)-targeting drug, cetuximab, conjugated to a light-activatable dye, IRDye® 700DX, and a laser light. Localized illumination results in rapid and selective tumor necrosis in the preclinical setting, and early clinical studies demonstrate a manageable safety profile in patients with head and neck squamous cell carcinoma. In the ongoing clinical trials, however, edema is a commonly reported adverse event and laryngeal edema, requiring prophylactic tracheostomy, has been noted in some patients. Thus, a critical need exists to provide clinicians with tools to manage ASP-1929 PIT-associated edema to ensure optimal patient outcome. To evaluate edema following cancer-targeted PIT, we developed a mouse tumor model and used it to characterize the mechanism of edema development and evaluate various methods for edema reduction. Briefly, cohorts of mice bearing syngeneic LL/2 tumors engineered to express Ephrin A2 (EphA2) were administered an anti-EphA2 antibody conjugated to IR700 (conjugate) or saline control. Light was applied 24h following administration and edema was measured by caliper. In control mice, light alone did not generate edema; however, mice treated with conjugate plus light showed a light-dose dependent increase in edema volume which peaked at 6h post light delivery. We next evaluated a series of inflammatory cytokines and immune cell populations in the blood and tumor region at the onset (2h), peak (6h), and resolution (24h) of PIT-induced edema. We found a striking increase in neutrophils (500-fold greater than control mice, n=10, p<0.0001) in the blood at the peak of edema formation coinciding with a significant increase in IL-6 (n=5, p<0.001) and IL-10 (n=5, p<0.05), indicating the onset of a heightened inflammatory response. To combat the edema formation, we next evaluated the effect of various anti-inflammatory drugs commonly used in the clinical setting. Cohorts of mice were administered conjugate plus light in the presence or absence of steroids or the selective COX-2 inhibitor meloxicam. Results show there is no reduction in edema by steroids regardless of timing of administration. Conversely, the addition of meloxicam resulted in a significant reduction in edema at all time points and light doses evaluated: 40-50% reduction at both 2h and 6h post-PIT when administered prophylactically and 25% reduction at 6h post-PIT when administered post-light (all settings, n=10, p<0.0001). Importantly, we found the reduction in edema with meloxicam was not associated with a loss of therapeutic benefit based on measurement of tumor growth. In conclusion, the use of COX-2 inhibitors may be directly translated to the clinic for the benefit of patients receiving ASP-1929 PIT and should undergo further evaluation. Citation Format: Gina Ma, Myra Gordon, Jason Lapetoda, Abram Lozano, Christopher M. Amantea, Takuya Osada, Amy H. Thorne. Reduction in photoimmunotherapy-induced edema with COX-2 inhibition: Combatting clinically relevant adverse events without compromising efficacy [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 1415.

Breaking Physical Barrier of Fibrotic Breast Cancer for Photodynamic Immunotherapy by Remodeling Tumor Extracellular Matrix and Reprogramming Cancer-Associated Fibroblasts.

Cancer-associated fibroblasts (CAFs) assist in breast cancer (BRCA) invasion and immune resistance by overproduction of extracellular matrix (ECM). Herein, we develop FPC@S, a photodynamic immunomodulator that targets the ECM, to improve the photodynamic immunotherapy for fibrotic BRCA. FPC@S combines a tumor ECM-targeting peptide, a photosensitizer (protoporphyrin IX) and an antifibrotic drug (SIS3). After anchoring to the ECM, FPC@S causes ECM remodeling and BRCA cell death by generating reactive oxygen species (ROS) in situ. Interestingly, the ROS-mediated ECM remodeling can normalize the tumor blood vessel to improve hypoxia and in turn facilitate more ROS production. Besides, upon the acidic tumor microenvironment, FPC@S will release SIS3 for reprograming CAFs to reduce their activity but not kill them, thus inhibiting fibrosis while preventing BRCA metastasis. The natural physical barrier formed by the dense ECM is consequently eliminated in fibrotic BRCA, allowing the drugs and immune cells to penetrate deep into tumors and have better efficacy. Furthermore, FPC@S can stimulate the immune system and effectively suppress primary, distant and metastatic tumors by combining with immune checkpoint blockade therapy. This study provides different insights for the development of fibrotic tumor targeted delivery systems and exploration of synergistic immunotherapeutic mechanisms against aggressive BRCA.

Ligand Regulation Strategy to Modulate ROS Nature in a Rhodamine-Iridium(III) Hybrid System for Phototherapy.

The efficacy of photodynamic therapy (PDT) is highly dependent on the photosensitizer features. The reactive oxygen species (ROS) generated by photosensitizers is proven to be associated with immunotherapy by triggering immunogenic cell death (ICD) as well. In this work, we establish a rhodamine-iridium(III) hybrid model functioning as a photosensitizer to comprehensively understand its performance and potential applications in photodynamic immunotherapy. Especially, the correlation between the ROS generation efficiency and the energy level of the Ir(III)-based excited state (T1'), modulated by the cyclometalating (C∧N) ligand, is systematically investigated and correlated. We prove that in addition to the direct population of the rhodamine triplet state (T1) formed through the intersystem crossing process with the assistance of a heavy Ir(III) metal center, the fine-tuned T1' state could act as a relay to provide an additional pathway for promoting the cascade energy transfer process that leads to enhanced ROS generation ability. Moreover, type I ROS can be effectively produced by introducing sulfur-containing thiophene units in C∧N ligands, providing a stronger M1 macrophage-activation efficiency under hypoxia to evoke in vivo antitumor immunity. Overall, our work provides a fundamental guideline for the molecular design and exploration of advanced transition-metal-based photosensitizers for biomedical applications.

Enhancing photodynamic immunotherapy by reprograming the immunosuppressive tumor microenvironment with hypoxia relief

Tumor hypoxia impairs the generation of reactive oxygen species and the induction of immunogenic cell death (ICD) for photodynamic therapy (PDT), thus impeding its efficacy and the subsequent immunotherapy. In addition, hypoxia plays a critical role in forming immunosuppressive tumor microenvironments (TME) by regulating the infiltration of immunosuppressive tumor-associated macrophages (TAMs) and the expression of programmed death ligand 1 (PD-L1). To simultaneously tackle these issues, a MnO2-containing albumin nanoplatform co-delivering IR780, NLG919, and a paclitaxel (PTX) dimer is designed to boost photodynamic immunotherapy. The MnO2-catalyzed oxygen supply bolsters the efficacy of PDT and PTX-mediated chemotherapy, collectively amplifying the induction of ICD and the expansion of tumor-specific cytotoxic T lymphocytes (CTLs). More importantly, hypoxia releif reshapes the immunosuppressive TME via down-regulating the intratumoral infiltration of M2-type TAMs and the PD-L1 expression of tumor cells to enhance the infiltration and efficacy of CTLs in combination with immune checkpoint blockade (ICB) by NLG919, consequently eradicating primary tumors and almost completely preventing tumor relapse and metastasis. This study sets an example of enhanced immunotherapy for breast cancers through dual ICD induction and simultaneous immunosuppression modulation via both hypoxia relief and ICB, providing a strategy for the treatment of other hypoxic and immunosuppressive cancers.

Endoplasmic Reticulum-Targeting Self-Assembly Nanosheets Promote Autophagy and Regulate Immunosuppressive Tumor Microenvironment for Efficient Photodynamic Immunotherapy.

The poor efficiency and low immunogenicity of photodynamic therapy (PDT), and the immunosuppressive tumor microenvironment (ITM) lead to tumor recurrence and metastasis. In this work, TCPP-TER -Zn@RSV nanosheets (TZR NSs) that co-assembled from the endoplasmic reticulum (ER)-targeting photosensitizer TCPP-TER -Zn nanosheets (TZ NSs for short) and the autophagy promoting and indoleamine-(2, 3)-dioxygenase (IDO) inhibitor-like resveratrol (RSV) are fabricated to enhance antitumor PDT. TZR NSs exhibit improved therapeutic efficiency and amplified immunogenic cancer cell death (ICD) by ER targeting PDT and ER autophagy promotion. TZR NSs reversed the ITM with an increase of CD8+ T cells and reduce of immunosuppressive Foxp3 regulatory T cells, which effectively burst antitumor immunity thus clearing residual tumor cells. The ER-targeting TZR NSs developed in this paper presents a simple but valuable reference for high-efficiency tumor photodynamic immunotherapy.

Tumor-targeted nanodrug FSGG/siGal-9 for transdermal photothermal immunotherapy of melanoma

Photothermal therapy (PTT) is a cancer-targeted treatment approach.The occurrence of tumors may be related to microbial infections (Viruses, bacteria, fungi, etc.), which probably provokes anti-tumor immunity. However, T cells in the context of cancer become exhausted and dysfunctional. Galectin-9 (Gal-9) is highly expressed in normal tissues and associates with body immune tolerance, and was firstly evidenced with much higher expression on the primary solid tumors than CD80/86 (B7) and CD274 (PD-L1) here, which suggests that Gal-9 may be a key factor in inhibiting the anti-tumor immunity, and its receptor T cell immunoglobulin and mucin domain 3 (TIM-3) was discovered on the cytotoxic T lymphocytes (CTL) with high expression as well based on the single cell analysis. The immune checkpoint communications showed that the Gal-9/TIM-3 axis played the most vital role on negatively regulating the anti-tumor immunity of CTL for melanoma. Then, we used a novel transdermal photothermal nanosensitizer (FSGG) loading Gal-9 siRNA (FSGG/siGal-9) for knocking the tumor cells down Gal-9 to block the Gal-9/TIM-3 axis and prohibit CTL exhaustion synergizing PTT against melanoma, which evidenced good effects on inhibiting tumor growth and enhancing anti-tumor immunity, named “photothermal immunotherapy”. This paper provides a new perspective for tumor prevention and treatment.

An Activatable Dual Polymer Nanosystem for Photoimmunotherapy and Metabolic Modulation of Deep-Seated Tumors.

Nanomedicine in combination with immunotherapy has shown great potential in the cancer treatment, but phototherapeutic nanomaterials that specifically activate the immunopharmacological effects in deep tumors have rarely been developed due to limited laser penetration depth and tumor immune microenvironment. Herein, this work reports a newly synthesized semiconducting polymer (SP) grafted with imiquimod R837 and indoxmid encapsulated micelle (SPRIN-micelle) with strong absorption in the second near infrared window (NIR-II) that can relieve tumor immunosuppression and enhance the photothermal immunotherapy and catabolic modulation on tumors. Immune agonists (Imiquimod R837) and immunometabolic modulators (indoxmid) are covalently attached to NIR-II SP sensors via a glutathione (GSH) responsive self-immolation linker and then loaded into Pluronic F127 (F127) micelles by a temperature-sensitive critical micelle concentration (CMC)-switching method. Using this method, photothermal effect of SPRIN-micelles in deep-seated tumors can be activated, leading to effective tumor ablation and immunogenic cell death (ICD). Meanwhile, imiquimod and indoxmid are tracelessly released in response to the tumor microenvironment, resulting in dendritic cell (DC) maturation by imiquimod R837 and inhibition of both indoleamine 2,3-dioxygenase (IDO) activity and Treg cell expression by indoxmid. Ultimately, cytotoxic T-lymphocyte infiltration and tumor metastasis inhibition in deep solid tumors (9mm) are achieved. In summary, this work demonstrates a new strategy for the combination of photothermal immunotherapy and metabolic modulation by developing a dual functional polymer system including activable SP and temperature-sensitive F127 for the treatment of deep solid tumors.

A self-assembly active nanomodulator based on berberine for photothermal immunotherapy of breast cancer via dual regulation of immune suppression

Breast cancer (BC) remains a significant global health concern, especially affecting women, necessitating the development of effective treatment strategies. Photothermal immunotherapy has holds promise for addressing BC by eradicating tumors, preventing metastasis, and reducing recurrence rates. However, the dynamic amplification of indoleamine 2,3-dioxygenase 1 (IDO-1) and programmed cell death-ligand 1 (PD-L1) triggered by photothermal therapy (PTT) poses presents a significant barrier to immune cell infiltration, thus promoting immune evasion. To enhance overall efficiency, a hyaluronic acid (HA)-coated berberine (BBR)-indocyanine green self-assembly active nano modulator (HBI NDs) was successfully developed. This nano modulator aims to reverse immune resistance and further contribute to the synergistic anti-tumor effects. The prepared HBI NDs demonstrated a uniform spherical morphology, high drug loading, and favorable optical properties. The results based on in vitro cell experiments and tumor animal models confirmed that HBI NDs selectively accumulated in tumor tissues, downregulated PD-L1 and IDO-1 protein expression, and induced elevated cell apoptosis. Consequently, these effects result in efficient immune infiltration and positive anti-tumor outcomes. In conclusion, the HBI NDs nanodrug exhibits considerable potential as a novel agent for enhancing anticancer efficacy and promoting immune infiltration.

Cell Membrane‐Targeting Type I/II Photodynamic Therapy Combination with FSP1 Inhibition for Ferroptosis‐enhanced Photodynamic Immunotherapy

AbstractAn imbalance in reactive oxygen species (ROS) levels in tumor cells can result in the accumulation of lipid peroxide (LPO) which could induce ferroptosis. Moreover, elevated ROS levels in tumors present a chance to develop ROS‐based cancer therapeutics including photodynamic therapy and ferroptosis. However, their anticancer efficacies are compromised by the insufficient oxygen levels in solid tumors and inherent cellular ROS regulatory mechanism. Herein, we develop a cell membrane‐targeting photosensitizer, TBzT‐CNQi, which could generate 1O2, •OH, and O2•− via type I/II process to induce a high level of LPO for potent ferroptosis and photodynamic therapy. The FSP1 inhibitor (iFSP1) is incorporated with the cell membrane‐targeting type I/II PDT based on TBzT‐CNQi to down‐regulate FSP1 expression, lower the intracellular CoQ10 content, induce a high level of LPO, and activate initial tumor immunogenic ferroptosis. In vitro and in vivo experiments demonstrate that the cell membrane‐tergeting type I/II photodynamic therapy combination with FSP1 inhibition can evoke a strong ICD and activate the immune response, which subsequently promotes the invasion of CD8+ T cells infiltration, facilitates the dendritic cell maturation, and decreases the tumor infiltration of tumor‐associated macrophages. The study indicates that the combination of cell membrane‐targeting type I/II PDT and FSP1 inhibition holds promise as a potential strategy for ferroptosis‐enhanced photodynamic immunotherapy of hypoxia tumors.This article is protected by copyright. All rights reserved

Suppressing the Hypoxia‐Adenosinergic Axis by a Tailored Nanoreactor for Enhanced Photothermal Immunotherapy

Cell metabolite adenosine can induce extensive and persistent immunosuppression by binding to adenosine receptors on immune cells. Seriously, the hypoxia‐driven adenosinergic axis aggravates adenosine accumulation via dephosphorizing immune‐activating adenosine triphosphate (ATP) released during immunogenic cell death (ICD). Different from direct adenosine clearance or adenosine receptor blockade or directly using ecto‐enzyme (CD39/CD73) antagonist, it is hoped to use an innovative small science engineering to regulate the upstream hypoxia/HIF‐1α signal of the hypoxia‐adenosinergic axis, thereby reducing the immunosuppressive extracellular adenosine and enhancing ICD‐triggered antitumor immunity. PM@Mn is constructed by gradually integrating metformin and MnO2 on polydopamine (PDA) nanoparticles. PM@Mn can effectively suppress hypoxia‐adenosinergic axis via combining catalytic oxygen production with reduced endogenous oxygen consumption. Such motif of hypoxia relief suppresses the metabolism of ATP to adenosine via down‐regulating the expression of HIF‐1α, CD39, and CD73. Meanwhile, PDA in PM@Mn can induce local tumor ablation and trigger the “vaccine effect” of ICD under near‐infrared radiation. In a mouse breast cancer model with low immunogenicity, our strategy can effectively reduce adenosine accumulation, PM@Mn group exhibits 4.51‐fold cytotoxic T lymphocyte infiltration and tumor inhibition rate of 75.4%. This study provides a new strategy to advance ICD‐triggered antitumor immunity through supressing hypoxia‐adenosinergic axis.

Supramolecular prodrug-like nanotheranostics with dynamic and activatable nature for synergistic photothermal immunotherapy of metastatic cancer

Synergistic photothermal immunotherapy has attracted widespread attention due to the mutually reinforcing therapeutic effects on primary and metastatic tumors. However, the lack of clinical approval nanomedicines for spatial, temporal, and dosage control of drug co-administration underscores the challenges facing this field. Here, a photothermal agent (Cy7-TCF) and an immune checkpoint blocker (NLG919) are conjugated via disulfide bond to construct a tumor-specific small molecule prodrug (Cy7-TCF-SS-NLG), which self-assembles into prodrug-like nano-assemblies (PNAs) that are self-delivering and self-formulating. In tumor cells, over-produced GSH cleaves disulfide bonds to release Cy7-TCF-OH, which re-assembles into nanoparticles to enhance photothermal conversion while generate reactive oxygen species (ROSs) upon laser irradiation, and then binds to endogenous albumin to activate near-infrared fluorescence, enabling multimodal imaging-guided phototherapy for primary tumor ablation and subsequent release of tumor-associated antigens (TAAs). These TAAs, in combination with the co-released NLG919, effectively activated effector T cells and suppressed Tregs, thereby boosting antitumor immunity to prevent tumor metastasis. This work provides a simple yet effective strategy that integrates the supramolecular dynamics and reversibility with stimuli-responsive covalent bonding to design a simple small molecule with synergistic multimodal imaging-guided phototherapy and immunotherapy cascades for cancer treatment with high clinical value.

Macrophages‐Based Biohybrid Microrobots for Breast Cancer Photothermal Immunotherapy by Inducing Pyroptosis (Small 7/2024)

Macrophages‐Based Biohybrid Microrobots for Breast Cancer Photothermal Immunotherapy by Inducing Pyroptosis (Small 7/2024)

Mitochondrial Disruption Nanosystem Simultaneously Depressed Programmed Death Ligand-1 and Transforming Growth Factor-β to Overcome Photodynamic Immunotherapy Resistance.

Currently, limited photosensitizers possess the capacity to reverse tumor hypoxia and reduce programmed death ligand-1 (PD-L1) and transforming growth factor-β (TGF-β) expression simultaneously, hindering the perfect photodynamic therapy (PDT) effect due to acquired immune resistance and the tumor hypoxic microenvironment. To tackle these challenges, in this research, we demonstrated that mitochondrial energy metabolism depression can be utilized as an innovative and efficient approach for reducing the expression of PD-L1 and TGF-β simultaneously, which may offer a design strategy for a more ideal PDT nanosystem. Through proteomic analysis of 5637 cells, we revealed that tamoxifen (TMX) can incredibly regulate PD-L1 expression in tumor cells. Then, to selectively deliver clinically used mitochondrial energy metabolism depressant TMX to solid tumors as well as design an ideal PDT nanosystem, we synthesized MHI-TMX@ALB by combining a mitochondria-targeted heptamethine cyanine PDT-dye MHI with TMX through self-assembly with albumin (ALB). Interestingly enough, the MHI-TMX@ALB nanoparticle demonstrated effective reversion of tumor hypoxia and inhibition of PD-L1 protein expression at a lower dosage (7.5 times to TMX), which then enhanced the efficacy of photodynamic immunotherapy via enhancing T-cell infiltration. Apart from this, by leveraging the heptamethine dye's targeting capacity toward tumors and TMX's role in suppressing TGF-β, MHI-TMX@ALB also more effectively mitigated 4T1 tumor lung metastasis development. All in all, the MHI-TMX@ALB nanoparticle could be used as a multifunctional economical PD-L1 and TGF-β codepression immune-regulating strategy, broadening the potential clinical applications for a more ideal PDT nanosystem.

T lymphocyte-derived immunogenic hybrid nanovesicles for immunosuppression reversion and boosted photothermal immunotherapy

Photothermal therapy (PTT) can mediate the immunogenic cell death (ICD) of tumors through photothermal transformation, thus releasing tumor-associated antigens (TAAs) and damage-associated molecular patterns (DAMPs) to stimulate the maturation of dendritic cells (DCs) and elicit the immune response against tumors. However, PTT-mediated upregulation of the immune checkpoint molecule programmed cell death ligand 1 (PD-L1) will cause the immune evasion of tumor cells and thus increases the immunosuppression of cytotoxic T lymphocytes (CTLs), resulting in restricted photothermal immune activation. Taking advantage of the high expression of programmed cell death protein 1 (PD-1) in T lymphocytes, we develop an immunogenic photothermal hybrid nanovesicle to reverse immunosuppression and enhance PTT-induced ICD. The hybrid vesicle (TMVL-I) is constructed by phospholipid bilayer fusion of T cell-derived membrane vesicle (TMV) with high PD-1 expression and the indocyanine green (ICG)-loaded thermosensitive liposome (L-I). TMVL-Is bind to the tumor cells with PTT-induced upregulation of PD-L1, effectively blocking the PD-1/PD-L1 pathway between CTLs and tumor cells, thus reversing PD-L1-mediated tumor immunosuppression and intensifying photothermal-induced ICD effects. These processes significantly induce the maturation of DCs and enhance the infiltration of CTLs into both primary and distal tumors and the activation of spleen CTLs, strongly inhibiting the growth of B16 xenograft tumors and greatly improving the survival rate of B16 xenograft mice. This work provides a feasible strategy for immunosuppressive microenvironment reprogramming-based combination therapy.