Targeting Mitochondria for Cancer Photodynamic Therapy

Development of Dual-Targeted Mixed Micelles Loaded with Celastrol and Evaluation on Triple-Negative Breast Cancer Therapy

Considering that the precise delivery of Celastrol (Cst) into mitochondria to induce mitochondrial dysfunction may be a potential approach to improve the therapeutic outcomes of Cst on TNBC, a novel tumor mitochondria dual-targeted mixed-micelle nano-system was fabricated via self-synthesized triphenylphosphonium-modified cholesterol (TPP-Chol) and hyaluronic acid (HA)-modified cholesterol (HA-Chol). The Cst-loaded mixed micelles (Cst@HA/TPP-M) exhibited the characteristics of a small particle size, negative surface potential, high drug loading of up to 22.8%, and sustained drug release behavior. Compared to Cst-loaded micelles assembled only by TPP-Chol (Cst@TPP-M), Cst@HA/TPP-M decreased the hemolysis rate and upgraded the in vivo stability and safety. In addition, a series of cell experiments using the triple-negative breast cancer cell line MDA-MB-231 as a cell model proved that Cst@HA/TPP-M effectively increased the cellular uptake of the drug through CD44-receptors-mediated endocytosis, and the uptake amount was three times that of the free Cst group. The confocal results demonstrated successful endo-lysosomal escape and effective mitochondrial transport triggered by the charge converse of Cst@HA/TPP-M after HA degradation in endo-lysosomes. Compared to the free Cst group, Cst@HA/TPP-M significantly elevated the ROS levels, reduced the mitochondrial membrane potential, and promoted tumor cell apoptosis, showing a better induction effect on mitochondrial dysfunction. In vivo imaging and antitumor experiments based on MDA-MB-231-tumor-bearing nude mice showed that Cst@HA/TPP-M facilitated drug enrichment at the tumor site, attenuated drug systemic distribution, and polished up the antitumor efficacy of Cst compared with free Cst. In general, as a target drug delivery system, mixed micelles co-constructed by TPP-Chol and HA-Chol might provide a promising strategy to ameliorate the therapeutic outcomes of Cst on TNBC.

A Review of the Efficacy of Nanomaterial-Based Natural Photosensitizers to Overcome Multidrug Resistance in Cancer

Natural photosensitizers (PS) are compounds derived from nature, with photodynamic properties. Natural PSs have a similar action to that of commercial PSs, where cancer cell death occurs by necrosis, apoptosis, and autophagy through ROS generation. Natural PSs have garnered great interest over the last few decades because of their high biocompatibility and good photoactivity. Specific wavelengths could cause phytochemicals to produce harmful ROS for photodynamic therapy (PDT). However, natural PSs have some shortcomings, such as reduced solubility and lower uptake, making them less appropriate for PDT. Nanotechnology offers an opportunity to develop suitable carriers for various natural PSs for PDT applications. Various nanoparticles have been developed to improve the outcome with enhanced solubility, optical adsorption, and tumor targeting. Multidrug resistance (MDR) is a phenomenon in which tumor cells develop resistance to a wide range of structurally and functionally unrelated drugs. Over the last decade, several researchers have extensively studied the effect of natural PS-based photodynamic treatment (PDT) on MDR cells. Though the outcomes of clinical trials for natural PSs were inconclusive, significant advancement is still required before PSs can be used as a PDT agent for treating MDR tumors. This review addresses the increasing literature on MDR tumor progression and the efficacy of PDT, emphasizing the importance of developing new nano-based natural PSs in the fight against MDR that have the required features for an MDR tumor photosensitizing regimen.

Optimization of a Modular Nanotransporter Design for Targeted Intracellular Delivery of Photosensitizer

Modular nanotransporters (MNTs) are drug delivery systems for targeted cancer treatment. As MNTs are composed of several modules, they offer the advantage of high specificity and biocompatibility in delivering drugs to the target compartment of cancer cells. The large carrier module brings together functioning MNT modules and serves as a platform for drug attachment. The development of smaller-sized MNTs via truncation of the carrier module appears advantageous in facilitating tissue penetration. In this study, two new MNTs with a truncated carrier module containing either an N-terminal (MNTN) or a C-terminal (MNTC) part were developed by genetic engineering. Both new MNTs demonstrated a high affinity for target receptors, as revealed by fluorescent-labeled ligand-competitive binding. The liposome leakage assay proved the endosomolytic activity of MNTs. Binding to the importin heterodimer of each truncated MNT was revealed by a thermophoresis assay, while only MNTN possessed binding to Keap1. Finally, the photodynamic efficacy of the photosensitizer attached to MNTN was significantly higher than when attached to either MNTC or the original MNTs. Thus, this work reveals that MNT's carrier module can be truncated without losing MNT functionality, favoring the N-terminal part of the carrier module due to its ability to bind Keap1.

Current status and trend of mitochondrial research in lung cancer: A bibliometric and visualization analysis

This study summarizes and analyzes the relationship between mitochondria and the pathogenesis of lung cancer. The related articles in the Web of Science core literature database are searched and collected, and the data are processed by R software, Citespace, VOSviewer, and Excel. A total of 4476 related papers were retrieved, 4476 articles from 20162 co-authors of 3968 institutions in 84 countries and published in 951 journals. Through various bibliometric analysis tools, the relationship between mitochondria and the pathogenesis of lung cancer was analyzed, the previous research results were summarized, and the potential research direction was found.

A highly fluorescent and readily accessible all-organic photosensitizer model for advancing image-guided cancer PDT

The potential of using image-guided photodynamic therapy (ig-PDT) for cancer, especially with highly biocompatible fluorescent agents free of heavy atoms, is well recognized. This is due to key advantages related to minimizing adverse side effects associated with standard cancer chemotherapy. However, this theragnostic approach is strongly limited by the lack of synthetically-accessible and easily-modulable chemical scaffolds, enabling the rapid design and construction of advanced agents for clinical ig-PDT. In fact, there are still very few ig-PDT agents clinically approved. Herein we report a readily accessible, easy-tunable and highly fluorescent all-organic small photosensitizer, as a model design for accelerating the development and translation of advanced ig-PDT agents for cancer. This scaffold is based on BODIPY, which assures high fluorescence, accessibility, and ease of performance adaptation by workable chemistry. The optimal PDT performance of this BODIPY dye, tested in highly resistant pancreatic cancer cells, despite its high fluorescent behavior, maintained even after fixation and cancer cell death, is based on its selective accumulation in mitochondria. This induces apoptosis upon illumination, as evidenced by proteomic studies and flow cytometry. All these characteristics make the reported BODIPY-based fluorescent photosensitizer a valuable model for the rapid development of ig-PDT agents for clinical use.

Bibliometric and visual analysis in the field of two-dimensions nano black phosphorus in cancer from 2015 to 2023

This study aims to provide a comprehensive summary of the status and trends of Two-Dimensional Nano Black Phosphorus (2D nano BP) in cancer research from 2015 to 2023, offering insights for future studies. To achieve this, articles from the Web of Science database published between 2015 and 2023 were analyzed using R and VOSviewer software. The analysis included 446 articles, revealing a consistent increase in publication rates, especially between 2017 and 2019. China emerged as a leader in both publication volume and international collaborations. Prominent journals in this field included ACS Applied Materials & Interfaces and Advanced Materials, while key researchers were identified as Zhang Han, Tao Wei, and Yu Xuefeng. The analysis highlighted common keywords such as drug delivery, photothermal therapy, photodynamic therapy, and immunotherapy, indicating the major research focuses. The findings suggest that 2D nano BP holds significant promise in cancer treatment research, with a growing global interest. This study thus serves as a valuable reference for future investigations, providing a detailed analysis of the current state and emerging trends in this promising field.

Mitochondrial-targeted cyclometalated Ir(III)-5,7-dibromo/dichloro-2-methyl-8-hydroxyquinoline complexes and their anticancer efficacy evaluation in Hep-G2 cells

Both 8-hydroxyquinoline compounds and iridium (Ir) complexes have emerged as potential novel agents for tumor therapy. In this study, we synthesized and characterized two new Ir(III) complexes, [Ir(L1)(bppy)2] (Br-Ir) and [Ir(L2)(bppy)2] (Cl-Ir), with 5,7-dibromo-2-methyl-8-hydroxyquinoline (HL-1) or 5,7-dichloro-2-methyl-8-hydroxyquinoline as the primary ligand. Complexes Br-Ir and Cl-Ir successfully inhibited antitumor activity in Hep-G2 cells. In addition, complexes Br-Ir and Cl-Ir were localized in the mitochondrial membrane and caused mitochondrial damage, autophagy, and cellular immunity in Hep-G2 cells. We tested the proteins related to mitochondrial and mitophagy by western blot analysis, which showed that they triggered mitophagy-mediated apoptotic cell death. Remarkably, complex Br-Ir showed high in vivo antitumor activity, and the tumor growth inhibition rate was 63.0% (P < 0.05). In summary, our study on complex Br-Ir revealed promising results in in vitro and in vivo antitumor activity assays.

Hydrogen Sulfide-Induced Activatable Photodynamic Therapy Adjunct to Disruption of Subcellular Glycolysis in Cancer Cells by a Fluorescence-SERS Bimodal Iridium Metal-Organic Hybrid

The practical application of photodynamic therapy (PDT) demands targeted and activatable photosensitizers to mitigate off-target phototoxicity common in "always on" photosensitizers during light exposure. Herein, a cyclometalated iridium complex-based activatable photodynamic molecular hybrid, Cy-Ir-7-nitrobenzofurazan (NBD), is demonstrated as a biomedicine for molecular precision. This design integrates a hydrogen sulfide (H2S)-responsive NBD unit with a hydroxy-appended iridium complex, Cy-Ir-OH. In normal physiological conditions, the electron-rich Ir metal center exerts electron transfer to the NBD unit, quenches the excited state dynamics, and establishes a PDT-off state. Upon exposure to H2S, Cy-Ir-NBD activates into the potent photosensitizer Cy-Ir-OH through nucleophilic substitution. This mechanism ensures exceptional specificity, enabling targeted phototherapy in H2S-rich cancer cells. Additionally, we observed that Cy-Ir-NBD-induced H2S depletion disrupts S-sulfhydration of the glyceraldehyde-3-phosphate dehydrogenase enzyme, impairing glycolysis and ATP production in the cellular milieu. This sequential therapeutic process of Cy-Ir-NBD is governed by the positively charged central iridium ion that ensures mitochondria-mediated apoptosis in cancer cells. Dual-modality SERS and fluorescence imaging validate apoptotic events, highlighting Cy-Ir-NBD as an advanced theranostic molecular entity for activatable PDT. Finally, as a proof of concept, clinical assessment is evaluated with the blood samples of breast cancer patients and healthy volunteers, based on their H2S overexpression capability through SERS and fluorescence, revealing Cy-Ir-NBD to be a promising predictor for PDT activation in advanced cancer phototherapy.

Charge Transfer-Promoted Excited State of a Heavy-Atom-Free Photosensitizer for Efficient Application of Mitochondria-Targeted Fluorescence Imaging and Hypoxia Photodynamic Therapy

Conventional photosensitizers (PSs) used in photodynamic therapy (PDT) have shown preliminary success; however, they are often associated with several limitations including potential dark toxicity in healthy tissues, limited efficacy under acidic and hypoxic conditions, suboptimal fluorescence imaging capabilities, and nonspecific targeting during treatment. In response to these challenges, we developed a heavy-atom-free PS, denoted as Cz-SB, by incorporating ethyl carbazole into a thiophene-fused BODIPY core. A comprehensive investigation into the photophysical properties of Cz-SB was conducted through a synergistic approach involving experimental and computational investigations. The enhancement of intersystem crossing (kISC) and fluorescence emission (kfl) rate constants was achieved through a donor-acceptor pair-mediated charge transfer mechanism. Consequently, Cz-SB demonstrated remarkable efficiency in generating reactive oxygen species (ROS) under acidic and low-oxygen conditions, making it particularly effective for hypoxic cancer PDT. Furthermore, Cz-SB exhibited good biocompatibility, fluorescence imaging capabilities, and a high degree of localization within the mitochondria of living cells. We posit that Cz-SB holds substantial prospects as a versatile PS with innovative molecular design, representing a potential "one-for-all" solution in the realm of cancer phototheranostics.

Nanoassemblies of heptamethine cyanine dye-initiated poly(amino acid) enhance ROS generation for effective antitumour phototherapy

Phototherapy shows great potential for pinpoint tumour treatment. Heptamethine cyanine dyes like IR783 have high potential as agents for antitumour phototherapy due to their inherent tumour targeting ability, though their effectiveness in vivo is unsatisfactory for clinical translation. To overcome this limitation, we present an innovative strategy involving IR783-based polymeric nanoassemblies that improve the dye's performance as an antitumoural photosensitizer. In the formulation, IR783 is modified with cysteamine and used to initiate the ring-opening polymerization (ROP) of the N-carboxyanhydride of benzyl-L-aspartate (BLA), resulting in IR783-installed poly(BLA). Compared to free IR783, the IR783 dye in the polymer adopts a twisted molecular conformation and tuned electron orbital distribution, remarkably enhancing its optical properties. In aqueous environments, the polymers spontaneously assemble into nanostructures with 60 nm diameter, showcasing surface-exposed IR783 dyes that function as ligands for cancer cell and mitochondria targeting. Moreover, the nanoassemblies stabilized the dyes and enhanced the generation of reactive oxygen species (ROS) upon laser irradiation. Thus, in murine tumor models, a single injection of the nanoassemblies with laser irradiation significantly inhibits tumour growth with no detectable off-target toxicity. These findings highlight the potential for improving the performance of heptamethine cyanine dyes in antitumor phototherapy through nano-enabled strategies.

Water-Soluble Small Organic Fluorophores for Oncological Theragnostic Applications: Progress and Development

Cancer is one of the major noncommunicable diseases, responsible for millions of deaths every year worldwide. Though various cancer detection and treatment modalities are available today, many deaths occur owing to its late-stage detection and metastatic nature. Noninvasive detection using luminescence-based imaging tools is considered one of the promising techniques owing to its low cost, high sensitivity, and brightness. Moreover, these tools are unique and valuable as they can detect even the slightest changes in the cellular microenvironment. To achieve this, a fluorescent probe with strong tumor uptake and high spatial and temporal resolution, especially with high water solubility, is highly demanded. Recently, several water-soluble molecules with emission windows in the visible (400-700 nm), first near-infrared (NIR-I, 700-1000 nm), and second near-infrared (NIR-II, 1000-1700 nm) windows have been reported in literature. This review highlights recently reported water-soluble small organic fluorophores/dyes with applications in cancer diagnosis and therapeutics. We systematically highlight and describe the key concepts, structural classes of fluorophores, strategies for imparting water solubility, and applications in cancer therapy and diagnosis, i.e., theragnostics. We discuss examples of water-soluble fluorescent probes based on coumarin, xanthene, boron-dipyrromethene (BODIPY), and cyanine cores. Some other emerging classes of dyes based on carbocyclic and heterocyclic cores are also discussed. Besides, emerging molecular engineering methods to obtain such fluorophores are discussed. Finally, the opportunities and challenges in this research area are also delineated.

Photodynamic Therapy Induced Mitochondrial Targeting Strategies for Cancer Treatment: Emerging Trends and Insights

The perpetuity of cancer prevalence at a global level calls for development of novel therapeutic approaches with improved targetability and reduced adverse effects. Conventional cancer treatments have a multitude of limitations such as nonselectivity, invasive nature, and severe adverse effects. Chemotherapy is also losing its efficacy because of the development of multidrug resistance in the majority of cancers. To address these issues, selective targeting-based approaches are being explored for an effective cancer treatment. Mitochondria, being the moderator of a majority of crucial cellular pathways like metabolism, apoptosis, and reactive oxygen species (ROS) homeostasis, are an effective targeting site. Mitochondria-targeted photodynamic therapy (PDT) has arisen as a potential approach in this endeavor. By designing photosensitizers (PSs) that preferentially accumulate in the mitochondria, PDT offers a localized technique to induce cytotoxicity in cancer cells. In this review, we intend to explore the crucial principles and challenges associated with mitochondria-targeted PDT, including variability in mitochondrial function, mitochondria-specific PSs, targeted nanocarrier-based monotherapy, and combination therapies. The hurdles faced by this emerging strategy with respect to safety, optimization, clinical translation, and scalability are also discussed. Nonetheless, mitochondria-targeted PDT exhibits a significant capacity in cancer treatment, especially in combination with other therapeutic modalities. With perpetual research and technological advancements, this treatment strategy is a great addition to the arsenal of cancer treatment options, providing better tumor targetability while reducing the damage to surrounding healthy tissues. This review emphasizes the current status of mitochondria-targeted PDT, limitations, and future prospects in its pursuit of safe and efficacious cancer therapy.

Promising dawn in tumor microenvironment therapy: engineering oral bacteria

Despite decades of research, cancer continues to be a major global health concern. The human mouth appears to be a multiplicity of local environments communicating with other organs and causing diseases via microbes. Nowadays, the role of oral microbes in the development and progression of cancer has received increasing scrutiny. At the same time, bioengineering technology and nanotechnology is growing rapidly, in which the physiological activities of natural bacteria are modified to improve the therapeutic efficiency of cancers. These engineered bacteria were transformed to achieve directed genetic reprogramming, selective functional reorganization and precise control. In contrast to endotoxins produced by typical genetically modified bacteria, oral flora exhibits favorable biosafety characteristics. To outline the current cognitions upon oral microbes, engineered microbes and human cancers, related literatures were searched and reviewed based on the PubMed database. We focused on a number of oral microbes and related mechanisms associated with the tumor microenvironment, which involve in cancer occurrence and development. Whether engineering oral bacteria can be a possible application of cancer therapy is worth consideration. A deeper understanding of the relationship between engineered oral bacteria and cancer therapy may enhance our knowledge of tumor pathogenesis thus providing new insights and strategies for cancer prevention and treatment.

Toxicity of superparamagnetic iron oxide nanoparticles on retinoblastoma mitochondria

PURPOSE

Retinoblastoma (RB) is one of the most important cancers in children with a higher rate of prevalence in developing countries. Despite different approaches to the treatment of RB, it seems necessary to discover a new approach to its treatment. Today, mitochondria are recognised as an important target in the treatment of cancer. Superparamagnetic iron oxide nanoparticles (SPIONs) have been studied by researchers due to their important biological effects.

METHODS

In this study, the effects of SPIONs on mitochondria isolated from Y79 retinoblastoma cells were investigated.

RESULTS

The results showed that SPIONs were able to increase the reactive oxygen species (ROS) level and subsequently damage the mitochondrial membrane and release cytochrome c a as one of the important pro-apoptotic proteins of RB mitochondria. Furthermore, the results indicated a decrease in cell viability and an increase in caspase-3 activity in Y79 retinoblastoma cells.

CONCLUSIONS

These events can lead to the killing of cancerous mitochondria. Our results suggest that SPIONs can cause mitochondrial dysfunction and death in RB mitochondria.

Charge transfer in TiO2-based photocatalysis: fundamental mechanisms to material strategies

Semiconductor-based photocatalysis has attracted significant interest due to its capacity to directly exploit solar energy and generate solar fuels, including water splitting, CO2 reduction, pollutant degradation, and bacterial inactivation. However, achieving the maximum efficiency in photocatalytic processes remains a challenge owing to the speedy recombination of electron-hole pairs and the limited use of light. Therefore, significant endeavours have been devoted to addressing these issues. Specifically, well-designed heterojunction photocatalysts have been demonstrated to exhibit enhanced photocatalytic activity through the physical distancing of electron-hole pairs generated during the photocatalytic process. In this review, we provide a systematic discussion ranging from fundamental mechanisms to material strategies, focusing on TiO2-based heterojunction photocatalysts. Current efforts are focused on developing heterojunction photocatalysts based on TiO2 for a variety of photocatalytic applications, and these projects are explained and assessed. Finally, we offer a concise summary of the main insights and challenges in the utilization of TiO2-based heterojunction photocatalysts for photocatalysis. We expect that this review will serve as a valuable resource to improve the efficiency of TiO2-based heterojunctions for energy generation and environmental remediation.

Cepharanthine synergizes with photodynamic therapy for boosting ROS-driven DNA damage and suppressing MTH1 as a potential anti-cancer strategy

OBJECTIVE

Photodynamic therapy (PDT) primarily treats skin diseases or cancer by generating reactive oxygen species (ROS) to damage cellular DNA, yet drug resistance limits its application. To tackle this problem, the present study was carried out to improve the efficacy of chlorin e6 (Ce6)-PDT using Cepharanthine (CEP) as well as to reveal the potential molecular mechanism.

MATERIALS AND METHODS

Lewis lung cancer cell line (LLC) was utilized as the cancer cell model. chlorin e6 (Ce6) acted as the photosensitizer to induce PDT. The in vitro anti-cancer efficacy was measured by CCK-8, Annexin-V/PI staining, and migration assay. The Ce6 uptake was observed using flow cytometry and confocal microscopy. The ROS generation was detected by the DCFH-DA probe. The analysis of MutT Homolog 1 (MTH1) expression, correlation, and prognosis in databases was conducted by bioinformatic. The MTH1 expression was detected through western blots (WB). DNA damage was assayed by WB, immunofluorescent staining, and comet assay.

RESULTS

Ce6-PDT showed robust resistance in lung cancer cells under certain conditions, as evidenced by the unchanged cell viability and apoptosis. The subsequent findings confirmed that the uptake of Ce6 and MTH1 expression was enhanced, but ROS generation with laser irradiation was not increased in LLC, which indicated that the ROS scavenge may be the critical reason for resistance. Surprisingly, bioinformatic and in vitro experiments identified that MTH1, which could prevent the DNA from damage of ROS, was highly expressed in lung cancer and thereby led to the poor prognosis and could be further up-regulated by Ce6 PDT. CEP exhibited a dose-dependent suppressive effect on the lung cancer cells. Further investigations presented that CEP treatment boosted ROS production, thereby resulting in DNA double-strand breakage (DDSB) with activation of MTH1, indicating that CEP facilitated Ce6-PDT-mediated DNA damage. Finally, the combination of CEP and Ce6-PDT exhibited prominent ROS accumulation, MTH1 inhibition, and anti-lung cancer efficacy, which had synergistic pro-DNA damage properties.

CONCLUSION

Collectively, highly expressed MTH1 and the failure of ROS generation lead to PDT resistance in lung cancer cells. CEP facilitates ROS generation of PDT, thereby promoting vigorous DNA damage, inactivating MTH1, alleviating PDT resistance, and ameliorating the anti-cancer efficacy of Ce6-PDT, provides a novel approach for augmented PDT.

Indocyanine green based photodynamic therapy for keloids: Fundamental investigation and clinical improvement

BACKGROUND

Keloid, a prevalent pathological skin lesion, presents significant challenges in terms of treatment efficacy. Photodynamic therapy (PDT), an increasingly popular adjuvant treatment, has shown significant potential in the management of various disorders, including cancer. However, the therapeutic potential of indocyanine green-mediated photodynamic therapy (ICG-PDT) for keloids has not yet been demonstrated.

METHODS

In this study, we divided the experimental groups into control group, Photothermal Therapy group, Photodynamic Therapy group, and Combined Therapy group. The in vitro investigation aimed to optimize the clinical application of PDT for keloid treatment by elucidating its underlying mechanism. Subsequently, on this basis, we endeavored to manage a clinical case of keloid by employing surgical intervention in conjunction with modified ICG-PDT.

RESULTS

Our investigation revealed an unexpected outcome that ICG-PDT maximally inhibited the cellular activity and migration of keloid fibroblasts only when photodynamic mechanism took effect. Additionally, the induction of autophagy and apoptosis, as well as the inhibition of collagen synthesis, were particularly evident in this experimental group. Furthermore, the above therapeutic effect could be achieved at remarkably low drug concentrations. Building upon the aforementioned experimental findings, we successfully optimized the treatment modality for the latest case and obtained a more favorable treatment outcome.

CONCLUSIONS

This study investigated the mechanism of ICG-PDT treatment and optimized the in vivo treatment regimen, demonstrating the significant therapeutic potential of ICG-PDT treatment in clinical keloid treatment.

Effects of Photodynamic Therapy on Tumor Metabolism and Oxygenation Revealed by Fluorescence and Phosphorescence Lifetime Imaging

This work was aimed at the complex analysis of the metabolic and oxygen statuses of tumors in vivo after photodynamic therapy (PDT). Studies were conducted on mouse tumor model using two types of photosensitizers-chlorin e6-based drug Photoditazine predominantly targeted to the vasculature and genetically encoded photosensitizer KillerRed targeted to the chromatin. Metabolism of tumor cells was assessed by the fluorescence lifetime of the metabolic redox-cofactor NAD(P)H, using fluorescence lifetime imaging. Oxygen content was assessed using phosphorescence lifetime macro-imaging with an oxygen-sensitive probe. For visualization of the perfused microvasculature, an optical coherence tomography-based angiography was used. It was found that PDT induces different alterations in cellular metabolism, depending on the degree of oxygen depletion. Moderate decrease in oxygen in the case of KillerRed was accompanied by an increase in the fraction of free NAD(P)H, an indicator of glycolytic switch, early after the treatment. Severe hypoxia after PDT with Photoditazine resulted from a vascular shutdown yielded in a persistent increase in protein-bound (mitochondrial) fraction of NAD(P)H. These findings improve our understanding of physiological mechanisms of PDT in cellular and vascular modes and can be useful to develop new approaches to monitoring its efficacy.

Nanoplatform-enhanced photodynamic therapy for the induction of immunogenic cell death

As an efficient, non-invasive, low-side-effect, and highly selective cancer therapy, photodynamic therapy (PDT) is used to treat various malignant tumors. However, the inefficiency of dealing with deep tumors and metastatic lesions highly limits the use of PDT. Immunogenic cell death (ICD) is a particular form of tumor cell death that could elicit a tumor-special immune response, leading to a systemic anti-tumor effect and providing therapeutic benefits for metastatic lesions. In this regard, it is crucial to enhance the ability of PDT to induce ICD. Luckily, advanced nanotechnology created many promising ways to improve the immunogenicity of PDT and achieve photoimmunotherapy. This review summarizes the emerging strategies for triggering immunogenic cell death via nanoplatform-enhanced PDT, with particular emphasis on their advantages in photoimmunotherapy. We highlight the nanoplatforms classified according to the basic principles of photodynamic therapy and immunogenic cell death, which provides a valuable reference for the design of nanoplatform for photoimmunotherapy. In addition, we also discuss the current situation and prospect of nano-based photoimmunotherapy in clinical studies.

Cyclometalated Ir(III) theranostic molecular probe enabled mitochondria targeted fluorescence-SERS-guided phototherapy in breast cancer cells

The increased energy demands inherent in cancer cells necessitate a dependence on mitochondrial assistance for their proliferation and metastatic activity. Herein, an innovative photo-medical approach has been attempted, specifically targeting mitochondria, the cellular powerhouses, to attain therapeutic benefit. This strategy facilitates the rapid and precise initiation of apoptosis, the programmed cell death process. In this goal, we have synthesized cyclometalated Iridium (III) molecular probes, denoted as Ir-CN and Ir-H, with a nitrile (CN) and a hydrogen-functionalized bipyridine as ancillary ligands, respectively. Ir-CN has shown superior photosensitizing properties and lower dark cytotoxicity compared to Ir-H in the breast cancer cell line MCF-7, positioning it as the preferred probe for photodynamic therapy (PDT). The synthesized Ir-CN induces alterations in mitochondrial membrane potential, disrupting the respiratory chain function, and generating reactive oxygen species that activate signaling pathways leading to cell death. The CN-conjugated bipyridine ligand in Ir-CN contributes to the intense red fluorescence and the positive charge on the central metal atom facilitates specific mitochondrial colocalization (colocalization coefficient of 0.90). Together with this, the Iridium metal, with strong spin-orbit coupling, efficiently generates singlet oxygen with a quantum yield of 0.79. Consequently, the cytotoxic singlet oxygen produced by Ir-CN upon laser exposure disrupts mitochondrial processes, arresting the electron transport chain and energy production, ultimately leading to programmed cell death. This mitochondrial imbalance and apoptotic induction were dually confirmed through various apoptotic assays including Annexin V staining and by mapping the molecular level changes through surface-enhanced Raman spectroscopy (SERS). Therefore, cyclometalated Ir-CN emerges as a promising molecular probe for cancer theranostics, inducing laser-assisted mitochondrial damage, as tracked through bimodal fluorescence and SERS.

Dual-wavelength responsive CuS@COF nanosheets for high-performance photothermal/photodynamic combination treatments

Photothermal therapy (PTT) makes it difficult to achieve good performance on tumor treatments due to insufficient photothermal conversion efficiency, etc. Combining PTT with photodynamic therapy (PDT) and other therapeutic tools can significantly enhance the tumor-killing ability and has been widely used in the development of therapeutic platforms. Copper sulfide nanoparticle (CuS NP) photothermal reagents have the advantages of low toxicity and simple synthesis; therefore, combining CuS NPs with PDT photosensitizers is an effective strategy to construct a PTT/PDT combination therapeutic platform. However, PDT photosensitizers and photothermal agents generally assembled through hydrophobic interaction, suffer from low coating efficiency or the risk of drug leakage, thus seriously restricting their applications. To address these challenges, CuS NPs with excellent photothermal conversion performance were selected as the core material to prepare CuS@COF nanosheets through a dual-ligand assistant strategy with 4,7-bis(4-aminophenyl)-2,1,3-benzothiadiazole (BTD) and 2,4,6-trihydroxybenzene-1,3,5-tricarbaldehyde (TP). As a PTT/PDT combination therapeutic platform, CuS@COF nanosheets possess a porous TP-BDT-based COF shell, and it can sufficiently contact oxygen to provide high singlet oxygen (1O2) yield under 505 nm laser irradiation. Upon illumination with a 1064 nm laser, CuS@COF nanosheets can effectively convert the photon energy into thermal energy with a photothermal conversion efficiency of 63.4%. The results of the CCK8 experiment showed that the phototoxicity of the PTT/PDT combination treatment reached 85.1%, which was much higher than the effect of a single treatment. It was also confirmed in vivo that the tumor inhibition effect of the PDT/PTT combination treatment group was much greater than that of the single treatment group.

Molecular Mechanism of Circ_0088300-BOLL Interaction Regulating Mitochondrial Metabolic Reprogramming and Involved in Gastric Cancer Growth and Metastasis

This study aims to investigate the effect and molecular mechanism of the interaction between circRNA circ_0088300 and the RNA binding protein (RBP) BOLL on the growth and metastasis of gastric cancer. A prognostic risk model was established by screening differentially expressed RBP genes from the TCGA database, and BOLL was identified as a critical RBP. Gene Set Enrichment analysis (GSEA) showed that BOLL was associated with mitochondrial function. The upregulation fold change of circ_0088300 was the highest in the GSE93541 data set, and the RPISeq database confirmed its binding relationship with BOLL. In vitro experiments showed that BOLL regulates mitochondrial metabolism and cancer cell function and circ_0088300 upregulates the expression level of BOLL. In vivo experiments demonstrated that knocking down circ_0088300 can inhibit tumor growth and metastasis, whereas overexpression of BOLL can reverse this effect. In conclusion, we have reached a preliminary conclusion that upregulation of BOLL by circ_0088300 promotes gastric cancer growth and metastasis by promoting mitochondrial metabolic reprogramming.

Melittin kills A549 cells by targeting mitochondria and blocking mitophagy flux

Melittin, a naturally occurring polypeptide found in bee venom, has been recognized for its potential anti-tumor effects, particularly in the context of lung cancer. Our previous study focused on its impact on human lung adenocarcinoma cells A549, revealing that melittin induces intracellular reactive oxygen species (ROS) burst and oxidative damage, resulting in cell death. Considering the significant role of mitochondria in maintaining intracellular redox levels and ROS, we further examined the involvement of mitochondrial damage in melittin-induced apoptosis in lung cancer cells. Our findings demonstrated that melittin caused changes in mitochondrial membrane potential (MMP), triggered mitochondrial ROS burst (Figure 1), and activated the mitochondria-related apoptosis pathway Bax/Bcl-2 by directly targeting mitochondria in A549 cells (Figure 2). Further, we infected A549 cells using a lentivirus that can express melittin-Myc and confirmed that melittin can directly target binding to mitochondria, causing the biological effects described above (Figure 2). Notably, melittin induced mitochondrial damage while inhibiting autophagy, resulting in abnormal degradation of damaged mitochondria (Figure 5). To summarize, our study unveils that melittin targets mitochondria, causing mitochondrial damage, and inhibits the autophagy-lysosomal degradation pathway. This process triggers mitoROS burst and ultimately activates the mitochondria-associated Bax/Bcl-2 apoptotic signaling pathways in A549 cells.

A Platinum(II) Boron-dipyrromethene Complex for Cellular Imaging and Mitochondria-targeted Photodynamic Therapy in Red Light

Cisplatin-derived platinum(II) complexes [Pt(NH3 )2 (pacac)](NO3 ) (1, DPP-Pt) and [Pt(NH3 )2 (Acac-RB)](NO3 ) (2, Acacplatin-RB), where Hpacac is 1,3-diphenyl-1,3-propanedione and HAcac-RB is a red-light active distyryl-BODIPY-appended acetylacetone ligand, are prepared, characterized and their photodynamic therapy (PDT) activity studied (RB abbreviated for red-light BODIPY). Complex 2 displayed an intense absorption band at λ=652 nm (ϵ=7.3×104  M-1  cm-1 ) and 601 nm (ϵ=3.1×104  M-1  cm-1 ) in 1 : 1 DMSO-DPBS (Dulbecco's Phosphate Buffered Saline). Its emission profile includes a broad maximum at ~673 nm (λex =630 nm). The fluorescence quantum yield (ΦF ) of HAcac-RB and 2 are 0.19 and 0.07, respectively. Dichlorodihydrofluorescein diacetate and 1,3-diphenylisobenzofuran assay of complex 2 indicated photogeneration of singlet oxygen (ΦΔ : 0.36) as reactive oxygen species (ROS). Light irradiation caused only minor extent of ligand release forming chemo-active cisplatin analogue. The complex showed ~70-100 fold enhancement in cytotoxicity on light exposure in A549 lung cancer cells and MDA-MB-231 multidrug resistant breast cancer cells, giving half maximal inhibitory concentration (IC50 ) of 0.9-1.8 μM. Confocal imaging showed its mitochondrial localization and complex 2 exhibited anti-metastasis properties. Immunostaining of β-tubulin and Annexin V-FITC/propidium iodide staining displayed complex 2 induced photo-selective microtubule rupture and cellular apoptosis, respectively.

Ru(II)-Cyanine Complexes as Promising Photodynamic Photosensitizers for the Treatment of Hypoxic Tumours with Highly Penetrating 770 nm Near-Infrared Light

Light-activated treatments, such as photodynamic therapy (PDT), provide temporal and spatial control over a specific cytotoxic response by exploiting toxicity differences between irradiated and dark conditions. In this work, a novel strategy for developing near infrared (NIR)-activatable Ru(II) polypyridyl-based photosensitizers (PSs) was successfully developed through the incorporation of symmetric heptamethine cyanine dyes in the metal complex via a phenanthrimidazole ligand. Owing to their strong absorption in the NIR region, the PSs could be efficiently photoactivated with highly penetrating NIR light (770 nm), leading to high photocytotoxicities towards several cancer cell lines under both normoxic and hypoxic conditions. Notably, our lead PS (Ru-Cyn-1), which accumulated in the mitochondria, exhibited a good photocytotoxic activity under challenging low-oxygen concentration (2 % O2 ) upon NIR light irradiation conditions (770 nm), owing to a combination of type I and II PDT mechanisms. The fact that the PS Protoporphyrin IX (PpIX), the metabolite of the clinically approved 5-ALA PS, was found inactive under the same challenging conditions positions Ru-Cyn-1 complex as a promising PDT agent for the treatment of deep-seated hypoxic tumours.

Stereospecificity of Ginsenoside AD-1 and AD-2 Showed Anticancer Activity via Inducing Mitochondrial Dysfunction and Reactive Oxygen Species Mediate Cell Apoptosis

In this paper, the anti-cancer activity and molecular mechanisms of the isomers of AD-1 and AD-2 (20(R)-AD-1, 20(R)-AD-2, 20(S)-AD-1 and 20(S)-AD-2) were investigated. The results indicated that all of the four compounds obviously suppressed the viability of various cancer cells, and the anti-cancer activity of 20(R)-AD-1 and 20(R)-AD-2 was significantly better than 20(S)-AD-1 and 20(S)-AD-2, especially for gastric cancer cells (BGC-803). Then, the differences in the anti-cancer mechanisms of the isomers were investigated. The data showed that 20(R)-AD-1 and 20(R)-AD-2 induced apoptosis and decreased MMP, up-regulated the expression of cytochrome C in cytosol, transferred Bax to the mitochondria, suppressed oxidative phosphorylation and glycolysis and stimulated reactive oxygen species (ROS) production. Apoptosis can be attenuated by the reactive oxygen species scavenger N-acetylcysteine. However, 20(S)-AD-1 and 20(S)-AD-2 barely exhibited the same results. The results indicated that 20(R)-AD-1 and 20(R)-AD-2 suppressed cellular energy metabolism and caused apoptosis through the mitochondrial pathway, which ROS generation was probably involved in. Above all, the data support the development of 20(R)-AD-1 and 20(R)-AD-2 as potential agents for human gastric carcinoma therapy.

A lysosomes and mitochondria dual-targeting AIE-active NIR photosensitizer: Constructing amphiphilic structure for enhanced antitumor activity and two-photon imaging

Development of lysosomes and mitochondria dual-targeting photosensitizer with the virtues of near-infrared (NIR) emission, highly efficient reactive oxygen generation, good phototoxicity and biocompatibility is highly desirable in the field of imaging-guided photodynamic therapy (PDT) for cancer. Herein, a new positively charged amphiphilic organic compound (2-(2-(5-(7-(4-(diphenylamino)phenyl)benzo[c][1,2,5]thiadiazol-4-yl)thiophen-2-yl)vinyl)-3-methylbenzo[d]thiazol-3-ium iodide) (ADB) based on a D-A-π-A structure is designed and comprehensively investigated. ADB demonstrates special lysosomes and mitochondria dual-organelles targeting, bright NIR aggregation-induced emission (AIE) at 736 ​nm, high singlet oxygen (¹O₂) quantum yield (0.442), as well as good biocompatibility and photostability. In addition, ADB can act as a two-photon imaging agent for the elaborate observation of living cells and blood vessel networks of tissues. Upon light irradiation, obvious decrease of mitochondrial membrane potential (MMP), abnormal mitochondria morphology, as well as phagocytotic vesicles and lysosomal disruption in cells are observed, which further induce cell apoptosis and resulting in enhanced antitumor activity for cancer treatment. In vivo experiments reveal that ADB can inhibit tumor growth efficiently upon light exposure. These findings demonstrate that this dual-organelles targeted ADB has great potential for clinical imaging-guided photodynamic therapy, and this work provides a new avenue for the development of multi-organelles targeted photosensitizers for highly efficient cancer treatment.

Novel Chlorin e6-Curcumin Derivatives as a Potential Photosensitizer: Synthesis, Characterization, and Anticancer Activity

Novel series of chlorin e6-curcumin derivatives were designed and synthesized. All the synthesized compounds 16, 17, 18, and 19 were tested for their photodynamic treatment (PDT) efficacy against human pancreatic cancer cell lines: AsPC-1, MIA-PaCa-2, and PANC-1. The cellular uptake study was performed in the aforementioned cell lines using fluorescence-activated cell sorting (FACS). 17, among the synthesized compounds with IC₅₀ values of 0.27, 0.42, and 0.21 µM against AsPC-1, MIA PaCa-2, and PANC-1 cell lines, respectively, demonstrated excellent cellular internalization capability and exhibited higher phototoxicity relative to the parent Ce6. The quantitative analyses using Annexin V-PI staining revealed that the 17-PDT-induced apoptosis was dose-dependent. In pancreatic cell lines, 17 reduced the expression of the anti-apoptotic protein, Bcl-2, and increased the pro-apoptotic protein, cytochrome C, which indicates the activation of intrinsic apoptosis, the primary cause of cancer cell death. Structure-activity relationship studies have shown that the incorporation of additional methyl ester moiety and conjugation to the enone moiety of curcumin enhances cellular uptake and PDT efficacy. Moreover, in vivo PDT testing in melanoma mouse models revealed that 17-PDT greatly reduced tumor growth. Therefore, 17 might be an effective photosensitizer for PDT anticancer therapy.

Prospects of Using Protein Engineering for Selective Drug Delivery into a Specific Compartment of Target Cells

A large number of proteins are successfully used to treat various diseases. These include natural polypeptide hormones, their synthetic analogues, antibodies, antibody mimetics, enzymes, and other drugs based on them. Many of them are demanded in clinical settings and commercially successful, mainly for cancer treatment. The targets for most of the aforementioned drugs are located at the cell surface. Meanwhile, the vast majority of therapeutic targets, which are usually regulatory macromolecules, are located inside the cell. Traditional low molecular weight drugs freely penetrate all cells, causing side effects in non-target cells. In addition, it is often difficult to elaborate a small molecule that can specifically affect protein interactions. Modern technologies make it possible to obtain proteins capable of interacting with almost any target. However, proteins, like other macromolecules, cannot, as a rule, freely penetrate into the desired cellular compartment. Recent studies allow us to design multifunctional proteins that solve these problems. This review considers the scope of application of such artificial constructs for the targeted delivery of both protein-based and traditional low molecular weight drugs, the obstacles met on the way of their transport to the specified intracellular compartment of the target cells after their systemic bloodstream administration, and the means to overcome those difficulties.

Effect of Arylazo Sulfones on DNA: Binding, Cleavage, Photocleavage, Molecular Docking Studies and Interaction with A375 Melanoma and Non-Cancer Cells

A set of arylazo sulfones, known to undergo N-S bond cleavage upon light exposure, has been synthesized, and their activity in the dark and upon irradiation towards DNA has been investigated. Their interaction with calf-thymus DNA has been examined, and the significant affinity observed (most probably due to DNA intercalation) was analyzed by means of molecular docking "in silico" calculations that pointed out polar contacts, mainly via the sulfonyl moiety. Incubation with plasmid pBluescript KS II revealed DNA cleavage that has been studied over time and concentration. UV-A irradiation considerably improved DNA damage for most of the compounds, whereas under visible light the effect was slightly lower. Moving to in vitro experiments, irradiation was found to slightly enhance the death of the cells in the majority of the compounds. Naphthylazosulfone 1 showed photo-disruptive effect under UV-A irradiation (IC50 ~13 μΜ) followed by derivatives 14 and 17 (IC50 ~100 μΜ). Those compounds were irradiated in the presence of two non-cancer cell lines and were found equally toxic only upon irradiation and not in the dark. The temporal and spatial control of light, therefore, might provide a chance for these novel scaffolds to be useful for the development of phototoxic pharmaceuticals.

Marine Compounds, Mitochondria, and Malignancy: A Therapeutic Nexus

The marine environment is important yet generally underexplored. It contains new sources of functional constituents that can affect various pathways in food processing, storage, and fortification. Bioactive secondary metabolites produced by marine microorganisms may have significant potential applications for humans. Various components isolated from disparate marine microorganisms, including fungi, microalgae, bacteria, and myxomycetes, showed considerable biological effects, such as anticancer, antioxidant, antiviral, antibacterial, and neuroprotective activities. Growing studies are revealing that potential anticancer effects of marine agents could be achieved through the modulation of several organelles. Mitochondria are known organelles that influence growth, differentiation, and death of cells via influencing the biosynthetic, bioenergetic, and various signaling pathways related to oxidative stress and cellular metabolism. Consequently, mitochondria play an essential role in tumorigenesis and cancer treatments by adapting to alterations in environmental and cellular conditions. The growing interest in marine-derived anticancer agents, combined with the development and progression of novel technology in the extraction and cultures of marine life, led to revelations of new compounds with meaningful pharmacological applications. This is the first critical review on marine-derived anticancer agents that have the potential for targeting mitochondrial function during tumorigenesis. This study aims to provide promising strategies in cancer prevention and treatment.

Targeting mitochondria in cancer therapy: Insight into photodynamic and photothermal therapies

Mitochondria are critical multifunctional organelles in cells that generate power, produce reactive oxygen species, and regulate cell survival. Mitochondria that are dysfunctional are eliminated via mitophagy as a way to protect cells under moderate stress and physiological conditions. However, mitophagy is a double-edged sword and can trigger cell death under severe stresses. By targeting mitochondria, photodynamic (PD) and photothermal (PT) therapies may play a role in treating cancer. These therapeutic modalities alter mitochondrial membrane potential, thereby affecting respiratory chain function and generation of reactive oxygen species promotes signaling pathways for cell death. In this regard, PDT, PTT, various mitochondrion-targeting agents and therapeutic methods could have exploited the vital role of mitochondria as the doorway to regulated cell death. Targeted mitochondrial therapies would provide an excellent opportunity for effective mitochondrial injury and accurate tumor erosion. Herein, we summarize the recent progress on the roles of PD and PT treatments in regulating cancerous cell death in relation to mitochondrial targeting and the signaling pathways involved.