Periodic mesoporous organosilica coupled with chlorin e6 and catalase for enhanced photodynamic therapy to treat triple-negative breast cancer

A Multi-Functional Cascade Nanoreactor for Remodeling Tumor Microenvironment to Realize Mitochondria Dysfunction via ROS/Zn2+ Ions Overload

Combining chemo/photodynamic therapy (CDT/PDT) to generate highly harmful reactive oxygen species and cause mitochondria dysfunction is considered a potential strategy to improve the efficiency of anticancer treatment. However, within tumor, the relatively deficient concentration of H2O2, hypoxic microenvironment, and overexpressed reduced glutathione (GSH) seriously suppress the efficacy of dynamic therapy. Herein, a multi-functional cascade nanoreactor, bovine serum albumin modified ZnO2@CeO2-ICG, is reported for remodeling tumor microenvironment (TME) to boost dynamic therapy and realize mitochondria dysfunction via reactive oxygen species (ROS) storm/Zn2+ ions overload. Within TME, ZnO2 decomposed into exogenous H2O2 and Zn2+ ion. The dual enzyme-like CeO2 catalyzes the increased H2O2 into ·OH and oxygen molecules respectively, and then the oxygen molecules are translated into 1O2 by indocyanine green (ICG) under 808 nm light irradiation to boost PDT. The effective consumption of GSH through the reduction of Ce(IV) ions not only regenerates Ce(III) ions to enhance the efficiency of CDT but also efficaciously alleviates the elimination of ROS generated by dynamic therapy to further improve dynamic therapeutic efficiency. So the improved ROS level under remodeling TME and Zn2+ ions acutely lead to mitochondria dysfunction to boost the efficiency of antitumor treatment. Thus, developing functional nanoreactors that enable remodeling TME provides a potential strategy to enhance the efficiency of dynamic therapy.

Synergistic effects of photodynamic therapy and chemotherapy: Activating the intrinsic/extrinsic apoptotic pathway of anoikis for triple-negative breast cancer treatment

Triple-negative breast cancer (TNBC) is a highly invasive and metastatic subtype of breast cancer that often recurs after surgery. Herein, we developed a cyclodextrin-based tumor-targeted nano delivery system that incorporated the photosensitizer chlorin e6 (Ce6) and the chemotherapeutic agent lonidamine (LND) to form the R6RGD-CMβCD-se-se-Ce6/LND nanoparticles (RCC/LND NPS). This nanosystem could target cancer cells, avoid lysosomal degradation and further localize within the mitochondria. The RCC/LND NPS had pH and redox-responsive to control the release of Ce6 and LND. Consequently, the nanosystem had a synergistic effect by effectively alleviating hypoxia, enhancing the production of cytotoxic reactive oxygen species (ROS) and amplifying the efficacy of photodynamic therapy (PDT). Furthermore, the RCC/LND NPS + light weakened anoikis resistance, disrupted extracellular matrix (ECM), activated both the intrinsic apoptotic pathway (mitochondrial pathway) and extrinsic apoptotic pathway (receptor death pathway) of anoikis. In addition, the nanosystem showed significant anti-TNBC efficacy in vivo. These findings collectively demonstrated that RCC/LND NPS + light enhanced the anticancer effects, induced anoikis and inhibited tumor cell migration and invasion through a synergistic effect of chemotherapy and PDT. Overall, this study highlighted the promising potential of the RCC/LND NPS + light for the treatment of TNBC.

Antioxidant Enzymes and Their Potential Use in Breast Cancer Treatment

According to the World Health Organization (WHO), breast cancer (BC) is the deadliest and the most common type of cancer worldwide in women. Several factors associated with BC exert their effects by modulating the state of stress. They can induce genetic mutations or alterations in cell growth, encouraging neoplastic development and the production of reactive oxygen species (ROS). ROS are able to activate many signal transduction pathways, producing an inflammatory environment that leads to the suppression of programmed cell death and the promotion of tumor proliferation, angiogenesis, and metastasis; these effects promote the development and progression of malignant neoplasms. However, cells have both non-enzymatic and enzymatic antioxidant systems that protect them by neutralizing the harmful effects of ROS. In this sense, antioxidant enzymes such as superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), glutathione reductase (GR), thioredoxin reductase (TrxR), and peroxiredoxin (Prx) protect the body from diseases caused by oxidative damage. In this review, we will discuss mechanisms through which some enzymatic antioxidants inhibit or promote carcinogenesis, as well as the new therapeutic proposals developed to complement traditional treatments.

Dual-Responsive hollow mesoporous organosilicon nanocarriers for photodynamic therapy

HYPOTHESIS

The nano-delivery platform, -SS-HMONs@MB@MnO2 nanoparticles (SMM NPs) loaded with methylene blue (MB) as photosensitizer have excellent photodynamic therapy (PDT) effect. The disulfide bond and MnO2 give the shell redox-responsive properties. SMM NPs consume glutathione (GSH) in tumor cells, reducing the scavenging of reactive oxygen species (ROS) by GSH and enhancing the PDT effect of MB.

EXPERIMENTS

The GSH dual-responsive nano-delivery platform, was designed and constructed by using disulfide-doped hollow mesoporous organosilicon nanoparticles (-SS-HMONs) as intermediate responsive layer, loaded with MB as photosensitizer and coated with MnO2 as shells. The MB photosensitizer release and GSH response were characterized. The PDT effect of nanoparticles was evaluated.

FINDINGS

The SMM NPs were uniform in size and well dispersed. The nanoparticles could react with GSH, leading to the decomposition of MnO2 shells and the breakage of disulfide bonds in -SS-HMONs, resulted in the release of MB photosensitizer. The cell experiment showed that SMM NPs had good ROS generating ability and PDT effect after being sucked by tumor cells, which could effectively kill tumor cells. However, in vivo experiments demonstrated that SMM NPs showed slight inhibition on tumor growth. The actual effect in animals was different from the effect in cells.

Towards overcoming obstacles of type II photodynamic therapy: Endogenous production of light, photosensitizer, and oxygen

Conventional photodynamic therapy (PDT) approaches face challenges including limited light penetration, low uptake of photosensitizers by tumors, and lack of oxygen in tumor microenvironments. One promising solution is to internally generate light, photosensitizers, and oxygen. This can be accomplished through endogenous production, such as using bioluminescence as an endogenous light source, synthesizing genetically encodable photosensitizers in situ, and modifying cells genetically to express catalase enzymes. Furthermore, these strategies have been reinforced by the recent rapid advancements in synthetic biology. In this review, we summarize and discuss the approaches to overcome PDT obstacles by means of endogenous production of excitation light, photosensitizers, and oxygen. We envision that as synthetic biology advances, genetically engineered cells could act as precise and targeted "living factories" to produce PDT components, leading to enhanced performance of PDT.

Multifunctional mesoporous silica nanoparticles for biomedical applications

Mesoporous silica nanoparticles (MSNs) are recognized as a prime example of nanotechnology applied in the biomedical field, due to their easily tunable structure and composition, diverse surface functionalization properties, and excellent biocompatibility. Over the past two decades, researchers have developed a wide variety of MSNs-based nanoplatforms through careful design and controlled preparation techniques, demonstrating their adaptability to various biomedical application scenarios. With the continuous breakthroughs of MSNs in the fields of biosensing, disease diagnosis and treatment, tissue engineering, etc., MSNs are gradually moving from basic research to clinical trials. In this review, we provide a detailed summary of MSNs in the biomedical field, beginning with a comprehensive overview of their development history. We then discuss the types of MSNs-based nanostructured architectures, as well as the classification of MSNs-based nanocomposites according to the elements existed in various inorganic functional components. Subsequently, we summarize the primary purposes of surface-functionalized modifications of MSNs. In the following, we discuss the biomedical applications of MSNs, and highlight the MSNs-based targeted therapeutic modalities currently developed. Given the importance of clinical translation, we also summarize the progress of MSNs in clinical trials. Finally, we take a perspective on the future direction and remaining challenges of MSNs in the biomedical field.

Antitumor Effect of Photodynamic Therapy/Sonodynamic Therapy/Sono-Photodynamic Therapy of Chlorin e6 and Other Applications

Chlorin e6 (Ce6) has been extensively researched and developed as an antitumor therapy. Ce6 is a highly effective photosensitizer and sonosensitizer with promising future applications in photodynamic therapy, dynamic acoustic therapy, and combined acoustic and light therapy for tumors. Ce6 is also being studied for other applications in fluorescence navigation, antibacterials, and plant growth regulation. Here we review the role and research status of Ce6 in tumor therapy and the problems and challenges of its clinical application. Other biomedical effects of Ce6 are also briefly discussed. Despite the difficulties in clinical application, Ce6 has significant advantages in photodynamic therapy (PDT)/sonodynamic therapy (SDT) against cancer and offers several possibilities in clinical utility.

Manipulate tumor hypoxia for improved photodynamic therapy using nanomaterials

Due to its low adverse effects, minimal invasiveness, and outstanding patient compliance, photodynamic therapy (PDT) has drawn a great deal of interest, which is achieved through incomplete reduction of O₂ by a photosensitizer under light illumination that produces amounts of reactive oxygen species (ROS). However, tumor hypoxia significantly hinders the therapeutic effect of PDT so that tumor cells cannot be eliminated, which results in tumor cells proliferating, invading, and metastasizing. Additionally, O₂ consumption during PDT exacerbates hypoxia in tumors, leading to several adverse events after PDT treatment. In recent years, various investigations have focused on conquering or using tumor hypoxia by nanomaterials to amplify PDT efficacy, which is summarized in this review. This comprehensive review's objective is to present novel viewpoints on the advancement of oxygenation nanomaterials in this promising field, which is motivated by hypoxia-associated anti-tumor therapy.