Endoplasmic Reticulum-Targeting AIE Photosensitizers to Boost Immunogenic Cell Death for Immunotherapy of Bladder Carcinoma

Molecular engineering strategies for fabricating type-I mitochondria-targeted aggregation-induced emission photosensitizers for apoptosis-ferroptosis synergistically boosting photodynamic therapy

The precise distribution and subcellular localization of photosensitizers (PSs) play a crucial role in maximizing the utilization of reactive oxygen species (ROS) and enhancing photodynamic therapy (PDT). However, the therapeutic efficacy of PDT is significantly compromised by the hypoxic microenvironment, particularly in malignant tumors. To address these challenges, we designed and synthesized three donor-donor-π-bridge-acceptor (D-D-π-A) type aggregation-induced emission (AIE) PSs: TCM-OTs, TCM-OH, and TCPy-OH. By fine-tuning the acceptor and donor substituents, we successfully modulated organelle-targeting specificity and ROS generation to mitigate hypoxia-related limitations. Among these compounds, TCM-OH emerged as a highly promising PS, exhibiting selective mitochondrial targeting and efficient type-I ROS generation. To further enhance its pharmacological properties, we encapsulated each PS into DSPE-PEG2k to form nanoparticles (NPs). Notably, TCM-OH NPs facilitated the production of superoxide (•O2-) and hydroxyl radicals (•OH) within mitochondria, leading to mitochondrial dysfunction and subsequent cell death via a synergistic ferroptosis-apoptosis pathway under light irradiation. Both in vitro and in vivo experiments demonstrated the potent therapeutic efficacy of this strategy, with minimal toxicity, underscoring its potential for hypoxic cancer treatment. Overall, this study provides a rational design framework for developing potent type-I PSs with multimodal capabilities for biomedical applications.

Hypoxia-responsive oncolytic conjugate triggers type-II immunogenic cell death for enhanced photodynamic immunotherapy

Immunogenic cell death (ICD) induced by photodynamic therapy (PDT) holds great promise for enhancing anti-tumor immunotherapy; however, its clinical efficacy is often hampered by suboptimal ICD induction and the exacerbation of an immunosuppressive tumor microenvironment (TME) following PDT. Herein, we present a tumor-targeted and hypoxia-responsive peptide-photosensitizer conjugate, A6-dMP-VP, which integrates an oncolytic peptide (dMP) with a CD44-targeting motif (A6), hypoxia-responsive groups, and the photosensitizer verteporfin (VP). Following systemic administration, A6-dMP-VP preferentially accumulates in 4T1 tumors, where the hypoxic TME triggers its response. Remarkably, the combined oncolytic activity and PDT effect of A6-dMP-VP effectively induce type-II ICD via mitochondrial disruption and endoplasmic reticulum stress, leading to robust antigen release. This process significantly enhances dendritic cell maturation and cytotoxic T cell priming, ultimately achieving potent suppression of both primary and metastatic tumors. Our findings establish A6-dMP-VP as a highly effective type-II ICD inducer, offering a novel strategy to overcome the limitations of PDT and advance photodynamic-oncolytic immunotherapy.

Targeting CALR reduces energy metabolism of esophageal cancer cells and inhibits tumor‑associated fibroblast infiltration

Calreticulin (CALR) supports the induction of dendritic cell maturation, which makes it a key target for effective esophageal squamous cell carcinoma (ESCC) immunotherapy. The mechanism of CALR in the immunotherapy of ESCC is not fully studied. The aim of the present study was to explore the contributing role of CALR in ESCC progression. The association of CALR expression with calnexin (CANX) and protein disulfide isomerase A3 (PDIA3) expression in ESCC was analyzed. The functions of CALR in ESCC cells were examined by detection of cell migration, endoplasmic reticulum (ER) stress, mitochondrial function, cytoskeletal remodeling, cell proliferation and apoptosis. The effects of CALR on tumor growth and tumor‑associated fibroblast infiltration were examined by subcutaneous xenograft assay. The expression of CALR, CANX and PDIA3 in ESCC tissue significantly increased and the expression of PDIA3 was positively associated with CANX. Overexpression of CALR resulted in enhanced cell proliferation, migration, ER stress, mitochondrial function and cytoskeletal remodeling; knockdown of CALR expression had the opposite effect. In the subcutaneous xenograft assay, knockdown CALR significantly inhibited the growth of esophageal cancer tumors, suppressed the invasion of tumor‑associated fibroblasts and decreased the expression of α‑smooth muscle actin (α‑SMA), fibroblast activation protein (FAP), fibroblast specific protein‑1 (FSP1), platelet‑derived growth factor and transforming growth factor beta (TGF‑β) in tumor tissue. These findings suggested that CALR promotes the progression of ESCC by regulating ER stress and mitochondrial function to mediate ATP production, cytoskeletal remodeling, cell proliferation and apoptosis through CANX and PDIA3. Knockdown CALR significantly inhibited tumor‑associated fibroblast infiltration and is a potential drug target for ESCC.

Nano co-inducer of immunogenic cell death and ferroptosis for anti-tumor immunotherapy

Due to population aging and lifestyle changes, the global tumor burden has increased, making tumor disease a significant challenge in public health. Recently, immunotherapy emerged as an effective approach for tumor treatment by activating and enhancing the body's immune system to precisely identify and attack tumor cells. However, its efficacy was limited by the "cold" immunosuppressive tumor microenvironment (ITME) and the tissue repair capabilities of tumors. To address this issue, we developed a dual-target ferroptosis immune-inducer, FTB@CC, which releases photosensitizer (PS), calcium (Ca2+), and Fe2+ under weakly acidic conditions. Upon near-infrared (NIR) laser irradiation, PSs induced endoplasmic reticulum (ER) stress, producing large amounts of reactive oxygen species (ROS) and releasing significant quantities of damage-associated molecular patterns (DAMPs), which mediated immunogenic cell death (ICD). Simultaneously, Ca2+ overload activates the inflammasome and amplifies cellular cytotoxicity for DAMPs release, eventually activating the ICD pathway. The supplementation of Fe2+ increased iron storage within tumor cells and downregulated the expression of glutathione peroxidase 4 (GPX4), leading to the accumulation of lipid peroxides (LPO) and ultimately resulting in ferroptosis. This multi-level interaction strategy restructured the ITME and induced ICD, overcoming the limitations of single-agent therapies, and significantly enhancing the efficacy of anti-PD-L1 antibody (α-PD-L1) in suppressing tumor cell immune evasion. As a result, it promoted the infiltration of immune cells and inhibited both distal and proximal tumors. This nano-integrated ICD-ferroptosis co-inducer offers an intelligent strategy for effectively overcoming ITME, thereby providing a promising avenue for advanced immunotherapeutic interventions.

Organelle-targeted small molecular photosensitizers for enhanced photodynamic therapy: a minireview for recent advances and potential applications

Photodynamic therapy (PDT) is a promising approach for cancer treatment that involves the use of photosensitizers to generate reactive oxygen species upon light irradiation, resulting in selective cytotoxicity. To enhance the efficiency of PDT, researchers have developed organelle-targeting photosensitizers that specifically accumulate in critical cellular organelles. This review provides a comprehensive overview of recent advancements in the development of organelle-targeting photosensitizers for PDT. Different organelles, including mitochondria, plasma membrane, lysosome, endoplasmic reticulum, lipid droplets, nucleus, and Golgi, have been targeted to improve the selectivity and effectiveness of PDT. Various strategies have been employed to design and synthesize these photosensitizers, optimizing their organelle-specific accumulation and photodynamic efficiency. This review discusses the principles and mechanisms underlying the design of organelle-targeting photosensitizers, along with their exceptional results achieved in preclinical studies. Furthermore, potential applications and challenges in the development of multi-organelles-targeting photosensitizers and the synergistic use of multiple photosensitizers targeting different organelles are highlighted. Overall, organelle-targeting photosensitizers offer a promising avenue for advancing the field of PDT and improving its clinical applicability.

Recent Advances in Aggregation-Induced Emission Bioconjugates

Fluorescence imaging technology is playing increasing roles in modern personalized and precision medicine. Thanks to their excellent photophysical properties, organic luminogens featuring aggregation-induced emission (AIE) characteristics (AIEgens) have attracted considerable attention over the past two decades. Because of their superior biocompatibility, ease of processing and functionalization, excellent water solubility, high responsiveness, and exceptional signal-to-noise ratio (SNR) for biotargets, AIE bioconjugates, formed by covalently linking AIEgens with biomolecules, have emerged as an ideal candidate for bioapplications. In this review, we summarize the progress in preparation, properties, and application of AIE bioconjugates in the last five years. Moreover, the challenges and opportunities of AIE bioconjugates are also briefly discussed.

Leading edge biosensing applications based on AIE technology

Luminescent materials provide a unique method for biological imaging. Luminescent probes can label molecules of interest and present luminescent signals. Bioluminescence bioimaging has shown great efficacy in environmental, live cell and animal studies. Light-emitting materials play a very wide role in the field of light-emitting devices and biosensing. Luminescent materials are usually used as solid films or aggregate states. However, it is difficult to monitor the selectivity and sensitivity of various ions and small molecules in living cells with ordinary luminescent materials due to the changes in various aspects of analytes. Organic luminescent materials exhibit aggregation-induced quenching (ACQ) on molecular aggregation, and the ACQ effect is very common, which greatly limits the application of luminescent materials in chemical sensing, especially in biological imaging. Academician Tang Benzhong proposed "aggregation-induced emission (AIE)" as a powerful method to solve the ACQ problem for the first time. In this paper, the working principle of AIE is reviewed, and the research on the core working mechanism of AIE technology is not only of great fundamental significance, but also can pave the way for practical innovation of AIE technology applications. In this review, we outline the current basic understanding of the working mechanism of AIE, collate the cutting-edge biosensing applications based on AIE technology, including applications based on AIE in substance detection, biological detection, and disease detection. At last, we discuss the future development of AIE research.

An Albumin-Photosensitizer Supramolecular Assembly with Type I ROS-Induced Multifaceted Tumor Cell Deaths for Photodynamic Immunotherapy

Photodynamic therapy holds great potentials in cancer treatment, yet its effectiveness in hypoxic solid tumor is limited by the oxygen-dependence and insufficient oxidative potential of conventional type II reactive oxygen species (ROS). Herein, the study reports a supramolecular photosensitizer, BSA@TPE-BT-SCT NPs, through encapsulating aggregation-enhanced emission photosensitizer by bovine serum albumin (BSA) to significantly enhance ROS, particularly less oxygen-dependent type I ROS for photodynamic immunotherapy. The abundant type I ROS generated by BSA@TPE-BT-SCT NPs induce multiple forms of programmed cell death, including apoptosis, pyroptosis, and ferroptosis. These multifaceted cell deaths synergistically facilitate the release of damage-associated molecular patterns and antitumor cytokines, thereby provoking robust antitumor immunity. Both in vitro and in vivo experiments confirmed that BSA@TPE-BT-SCT NPs elicited the immunogenic cell death, enhance dendritic cell maturation, activate T cell, and reduce myeloid-derived suppressor cells, leading to the inhibition of both primary and distant tumors. Additionally, BSA@TPE-BT-SCP NPs also exhibited excellent antitumor performance in a humanized mice model, evidenced by a reduction in senescent T cells among these activated T cells. The findings advance the development of robust type I photosensitizers and unveil the important role of type I ROS in enhancing multifaceted tumor cell deaths and antitumor immunogenicity.

Catalase-positive Staphylococcus epidermidis based cryo-millineedle platform facilitates the photo-immunotherapy against colorectal cancer via hypoxia improvement

The synergistic anti-tumor impact of phototherapy and a cascading immune response are profoundly limited by hypoxia and a weakened immune response. Intravenous and intratumoral injection of therapeutic drugs also cause pain, rapid drug clearance and low utilization rates. Here, a novel cryo-millineedle platform for intratumoral delivery of a phototherapy system, S.epi@IR820, is developed in this work, combining the properties of Staphylococcus epidermidis (S. epidermidis) and IR820 for photo-immunotherapy of colorectal cancer. In this cryo-millineedle platform, S. epidermidis enhances the near-infrared absorption and light stability of IR820 and catalyzes the decomposition of H2O2 into O2 via an endogenous catalase to relieve tumor hypoxia, improve phototherapy and enhance immunogenic cell death (ICD). More interestingly, the native immunogenicity of S. epidermidis and ICD elicited by phototherapy achieved a potent anti-tumor immune response. To the best of our knowledge, this is the first study to utilize native S. epidermidis to relieve hypoxia and facilitate phototherapy. Both in vitro and in vivo experiments showed that the millineedle based phototherapy system can efficiently catalyse the decomposition of H2O2 into O2, facilitate phototherapeutic killing of CT26 tumor cells by S.epi@IR820 and enhance ICD, thus successfully activated the immune response and achieved the photo-immunotherapy against colorectal cancer. In conclusion, this study provides a novel strategy for enhanced anti-tumor efficiency of photo-immunotherapy, and develops an effective method for orthotopic administration of tumors.

Recent advances in AIE-based platforms for cancer immunotherapy

Aggregation-induced emission luminogens (AIEgens) possess the unique property of enhanced fluorescence and photostability in aggregated states, making them exceptional materials for the convergence of imaging and phototherapy. With their inherent advantages, AIEgens are propelling the field of nanomedicine into a vibrant frontier in the phototheranostics of a spectrum of diseases, particularly in the realm of cancer immunotherapy. AIEgens-based therapeutics enhance the cancer immune response through a variety of approaches, including real-time image-guided precise therapy, induction of programmed cell death, metabolic reprogramming, and modulation of the tumor microenvironment. Additionally, they contribute to the synergistic effect of immune checkpoint inhibition, a pivotal aspect of modern cancer immunotherapy strategies. This review offers a comprehensive overview of the integration of AIEgens in nanomedicine and their role in immune adaptation, highlighting the advantages, basic action mechanisms, and recent advancement of AIEgens as promising therapeutic platform for cancer immunotherapy.

Strategically engineered Au(I) complexes for orchestrated tumor eradication via chemo-phototherapy and induced immunogenic cell death

Cancer is a significant cause of death around the world, and for many varieties, treatment is not successful. Therefore, there is a need for the development of innovative, efficacious, and precisely targeted treatments. Here, we develop a series of Au(I) complexes (1-4) through rational manipulation of ligand structures, thereby achieving tumor cell specific targeting and orchestrated tumor eradication via chemo-phototherapy and induced immunogenic cell death. A comprehensive exploration based on in vitro and in vivo female mice experimentation shows that complex 4 exhibits proficiency in specific tumor imaging, endoplasmic reticulum targeting, and has robust therapeutic capabilities. Mechanistic elucidation indicates that the anticancer effect derives from the synergistic actions of thioredoxin reductase inhibition, highly efficient reactive oxygen species production and immunogenic cell death. This work presents a report on a robust Au(I) complex integrating three therapeutic modalities within a singular system. The strategy presented in this work provides a valuable reference for the development of high-performance therapeutic agents.

Emerging role of immunogenic cell death in cancer immunotherapy: Advancing next-generation CAR-T cell immunotherapy by combination

Immunogenic cell death (ICD) is a stress-driven form of regulated cell death (RCD) in which dying tumor cells' specific signaling pathways are activated to release damage-associated molecular patterns (DAMPs), leading to the robust anti-tumor immune response as well as a reversal of the tumor immune microenvironment from "cold" to "hot". Chimeric antigen receptor (CAR)-T cell therapy, as a landmark in anti-tumor immunotherapy, plays a formidable role in hematologic malignancies but falls short in solid tumors. The Gordian knot of CAR-T cells for solid tumors includes but is not limited to, tumor antigen heterogeneity or absence, physical and immune barriers of tumors. The combination of ICD induction therapy and CAR-T cell immunotherapy is expected to promote the intensive use of CAR-T cell in solid tumors. In this review, we summarize the characteristics of ICD, stress-responsive mechanism, and the synergistic effect of various ICD-based therapies with CAR-T cells to effectively improve anti-tumor capacity.

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.