In Situ Activatable Nitrobenzene-Cysteine-Copper(II) Nano-complexes for Programmed Photodynamic Cancer Therapy

Design of photoactivatable methylene blue-bufalin conjugate for GPX4-targeted degradation to induce ferroptosis-like death in breast cancer therapy

Bufalin is a potent antitumor agent; however, its high toxicity limits its clinical application. Here, we explored the development of a novel photosensitizer-small molecule conjugate, MB-Buf, which combines the photosensitizer methylene blue (MB) with bufalin. The goal is to achieve targeted photodegradation of GPX4 upon light activation. The compound MB-Buf integrates the photodynamic properties of MB with the antitumor activity of bufalin. Under light irradiation, it generates reactive oxygen species (ROS), exhibiting photodynamic therapeutic activity, while its toxicity toward normal cells is reduced by 15-fold compared to bufalin alone. In vivo studies using a 4 T1-Luci xenograft mouse model demonstrated that MB-Buf, in combination with light irradiation, significantly inhibits tumor growth. These findings support MB-Buf as a promising new cancer treatment strategy, offering a potential approach to overcome the limitations of conventional therapies.

Lipoprotein-inspired in situ activatable photo-theranostic nitrobenzoselenadiazole-cholesterol for overcoming glioblastoma

Photo-theranostic materials are designed for both diagnostic imaging and therapeutic applications under specific light sources, particularly in translational medicine. While various photo-theranostic materials have been developed for disease treatment, their cooperative effects on biologically abundant species, such as proteins, have rarely been studied in terms of biological activity. In this work, we disclose a photo-theranostic agent (named NBSD-Chol) based on nitrobenzoselenadiazole (NBSD) and cholesterol (Chol), which is activatable in situ through lipoprotein hybridization. NBSD-Chol demonstrates outstanding potential for cancer imaging and photodynamic therapy (PDT) due to its unique properties, including (i) tumor targeting after oral uptake, (ii) tumor visualization under light irradiation for image-guided surgery, (iii) superior PDT effects, and (iv) downgrading hazard ratios (HR) related to clinically critical proteins. Overall, this work contributes to advancing translational medicine by developing innovative treatments for cancer using visible light, ushering in a new era of intraoperative technology and photodynamic fluorescence-guided surgical agents.

Rational Design of Methylene Blue-Raloxifene Conjugates for Efficient Breast Tumor Elimination Triggered by ERα Degradation

Small molecules capable of degrading estrogen receptor α (ERα) are of significant interest in breast cancer treatment. Herein, we rationally designed a series of ERα degraders (MR1-MR3) by conjugating methylene blue, a bifunctional photosensitizer, with the raloxifene pharmacophore. The lead compound MR3 exhibited high affinity to ERα, and it can induce a complete depletion of ERα in MCF7 breast cancer cells after 660 nm irradiation (0.4 W/cm2) for 1 min. Owing to the ERα degradation merit, MR3 displayed a 45-fold boosted anticancer activity (IC50 = 0.55 μM) after irradiation. In the breast cancer xenograft mouse model, MR3 induced an obvious tumor regression (tumor growth inhibition = 118%), which was superior to that of the FDA-approved ERα degrader Faslodex. These important features make MR3 extremely intriguing for breast cancer treatment.

Recent Advances of Nitrobenzoselenadiazole for Imaging and Therapy

The development and practical applications of multifunctional organic fluorophores have garnered significant attention in translational research in recent years. Among the fluorophores, nitrobenzodioxazole (NBD) has been widely used in various fields due to its small size and neutral character, both of which are advantageous for biorelated applications. However, NBD presents some limitations, including (1) suboptimal photophysical properties for in vivo applications and (2) its monofunctional nature, which restricts its use in fluorescence-based bioimaging and sensing. To overcome these challenges, recent research has focused on the development of nitrobenzoselenadiazole (NBSD) derivatives, a selenium analog of NBD. In this review article, we systematically summarize recent advancements in the development of NBSD and highlight examples of its application in translational research as a multifunctional organic fluorophore. We also explore the potential applications of NBSD and present representative case studies, providing valuable context for the ongoing development of new NBSD derivatives in the field of fluorophore-related material science.

Construction of nucleus-targeted photosensitizer and highly effective photodynamic immunotherapy for cancer

Nucleus is the largest and most important organelle within eukaryotic cells, containing most of the cell's genetic material, DNA. It serves as the central hub for genetic regulation and metabolism, making it an ideal target for subcellular drug delivery. The development of nucleus-targeted photosensitizers allows for the rapid and effective destruction of critical components such as DNA within the nucleus. This achieves the goal of efficiently eliminating cancer cells. However, most organic molecules, including photosensitizers, cannot penetrate the nuclear membrane, making the design and synthesis of nucleus-targeted photosensitizers both significant and challenging. The authors have designed and synthesized a nucleus-targeted activatable photosensitive probe (CMT-I). In vitro spectral analyses demonstrate that CMT-I is specifically activated by ct-DNA, significantly enhancing fluorescence-a 49-fold increase is observed upon binding. Furthermore, under 590 nm light irradiation, CMT-I effectively generates 1O2. Molecular docking show that CMT-I selectively binds to DNA through hydrogen bonds and ᴨ-ᴨ conjugation. RNA sequencing experiments reveal that photodynamic therapy activates immunity within tumor cells, triggering an adaptive immune response. In vivo therapeutic experiments further verify the enhanced anti-tumor immunity of CMT-I, which is crucial for effectively eliminating immunologically cold tumors and highlights the potential of DNA-targeted photodynamic therapy in precise cancer treatment.

Supramolecular assemblies with aggregation-induced emission for in situ active imaging-guided photodynamic therapy of cancer cells

Photodynamic therapy (PDT) has attracted widespread attention as a novel non-invasive anticancer approach. However, the diminished photosensitivity and limited oxygen exposure caused by the aggregation of traditional photosensitizers greatly impair its overall therapeutic efficacy. Herein, a series of water-soluble aggregation-induced emission luminogens (AIEgens) with triphenylamine as skeleton were synthesized and exhibited bright Near-infrared (NIR) emission and strong reactive oxygen species (ROS) generation. Through host-guest complexation between the multicharged triphenylamine units on AIEgens and cucurbit[10]uril (CB[10]) host molecule, supramolecular nanoassemblies were constructed and exhibited negligible phototoxicity to normal cells due to their limited oxygen contact. In contrast, the efficient release of AIEgens from nanoassemblies through competitive binding of overexpressed peptides in cancer cells with CB[10], enabled the full exploitation of the photosensitivity of AIEgens to produce highly efficient ROS, achieving selective ablation of cancer cells. Moreover, due to the restriction of intramolecular motion (RIM) upon anchored on organelle membranes through electrostatic interactions, the cationic AIEgens with weak fluorescence in physiological environment exhibited intense fluorescence emission, thus realizing imaging-guided PDT. This work may open up an avenue for the development of simple and feasible smart responsive nanomaterials for cancer treatment using supramolecular host-guest complexation strategy.

Porphyrin-based-MOF nanocomposite hydrogels for synergistic sonodynamic and gas therapy against tumor

The glioma is one of the most aggressive tumors in humans, which is difficult to eradicate clinically. Therefore, we devised a porphyrin-based metal-organic frameworks (MOFs) crosslinking hyaluronic acid (HA) hydrogel nanocomposite through double-network (Cu-MOF-S-S-HA-Gel, CSSH-Gel), which is tumor responsive for enhanced gas therapy and sonodynamic therapy (SDT). Firstly, the hydrogels show extraordinary injectability and biocompatibility, which enables intratumor administration to circumvent the danger associated with surgery. The Cu-MOF-Cys and HA-Cys are interconnected through ether and disulfide bonds to establish a dual-network gel structure. The overexpressed glutathione (GSH) in tumor microenvironment (TME) reacts with disulfide bonds to release of the nanosensitizer (Cu-MOF). Subsequently, Cu-MOF generates reactive oxygen species (ROS) upon ultrasound irradiation for SDT, and releases L-cysteine(L-Cys) catalyzed by 3-mercapto pyruvate sulfotransferase (3-MST) to generate H2S for gas therapy. The CSSH-Gel obtained excellent synergistic anti-tumor effects (82.34 % inhibition ratio in vivo), which holds tremendous promise for the advancement of minimally invasive glioma therapies.

A Copper Silicate-Based Multifunctional Nanoplatform with Glutathione Depletion and Hypoxia Relief for Synergistic Photodynamic/Chemodynamic Therapy

Chemodynamic therapy (CDT) alone cannot achieve sufficient therapeutic effects due to the excessive glutathione (GSH) and hypoxia in the tumor microenvironment (TME). Developing a novel strategy to improve efficiency is urgently needed. Herein, we prepared a copper silicate nanoplatform (CSNP) derived from colloidal silica. The Cu(II) in CSNP can be reduced to Cu(I), which cascades to induce a subsequent CDT process. Additionally, benefiting from GSH depletion and oxygen (O2) generation under 660 nm laser irradiation, CSNP exhibits both Fenton-like and hypoxia-alleviating activities, contributing to the effective generation of superoxide anion radical (•O2-) and hydroxyl radical (•OH) in the TME. Furthermore, given the suitable band-gap characteristic and excellent photochemical properties, CSNP can also serve as an efficient type-I photosensitizer for photodynamic therapy (PDT). The synergistic CDT/PDT activity of CSNP presents an efficient antitumor effect and biosecurity in both in vitro and in vivo experiments. The development of an all-in-one nanoplatform that integrates Fenton-like and photosensing properties could improve ROS production within tumors. This study highlights the potential of silicate nanomaterials in cancer treatment.

Two-Photon Photodegradation of E3 Ubiquitin Ligase Cereblon by a Ru(II) Complex: Inducing Ferroptosis in Cisplatin-Resistant Tumor Cells

Using photodynamic therapy (PDT) to trigger nonconventional cell death pathways has provided a new scheme for highly efficient and non-side effects to drug-resistant cancer therapies. Nonetheless, the unclear targets of available photosensitizers leave the manner of PDT-induced tumor cell death relatively unpredictable. Herein, we developed a novel Ru(II)-based photosensitizer, Ru-Poma. Possessing the E3 ubiquitin ligase CRBN-targeting moiety and high singlet oxygen yield of 0.96, Ru-Poma was demonstrated to specifically photodegrade endogenous CRBN, increase lipid peroxide, downregulate GPX4 and GAPDH expression, and consequently induce ferroptosis in cisplatin-resistant cancerous cells. Furthermore, with the deep penetration of two-photon excitation, Ru-Poma achieved drug-resistant circumvention in a 3D tumor cell model. Thus, we describe the first sample of the CRBN-targeting Ru(II) complex active in PDT.

Free Radicals Generated in Perfluorocarbon-Water (Liquid-Liquid) Interfacial Contact Electrification and Their Application in Cancer Therapy

Electron transfer during solid-liquid contact electrification has been demonstrated to produce reactive oxygen species (ROS) such as hydroxyl radicals (•OH) and superoxide anion radicals (•O2-). Here, we show that such a process also occurs in liquid-liquid contact electrification. By preparing perfluorocarbon nanoemulsions to construct a perfluorocarbon-water "liquid-liquid" interface, we confirmed that electrons were transferred from water to perfluorocarbon in ultrasonication-induced high-frequency liquid-liquid contact to produce •OH and •O2-. The produced ROS could be applied to ablate tumors by triggering large-scale immunogenic cell death in tumor cells, promoting dendritic cell maturation and macrophage polarization, ultimately activating T cell-mediated antitumor immune response. Importantly, the raw material for producing •OH is water, so the tumor therapy is not limited by the endogenous substances (O2, H2O2, etc.) in the tumor microenvironment. This work provides new perspectives for elucidating the mechanism of generation of free radicals in liquid-liquid contact and provides an excellent tumor therapeutic modality.