Biomimetic photosensitizer nanocrystals trigger enhanced ferroptosis for improving cancer treatment

Biomimetic Ghost Nanomedicine-Based Optotheranostics for Cancer

Theranostic medicine combines diagnostics and therapeutics, focusing on solid tumors at minimal doses. Optically activated photosensitizers are significant examples owing to their photophysical and chemical properties. Several optotheranostics have been tested that convert light to imaging signals, therapeutic radicals, and heat. Upon light exposure, conjugated photosensitizers kill tumor cells by producing reactive oxygen species and heat or by releasing cancer antigens. Despite clinical trials, these molecularly conjugated photosensitizers require protection from their surroundings and a localized direction for site-specific delivery during blood circulation. Therefore, cell membrane biomimetic ghosts have been proposed for precise and safe delivery of these optically active large molecules, which are clinically relevant because of their biocompatibility, long circulation time, bypass of immune cell recognition, and targeting ability. This review focuses on the role of biomimetic nanoparticles in the treatment and diagnosis of tumors through light-mediated diagnostics and therapy, providing insights into their preclinical and clinical status.

The phototoxic effect of a gold-antibody-based nanocarrier of phthalocyanine on melanoma monolayers and tumour spheroids

In recent years, photodynamic therapy (PDT) has garnered significant attention in cancer treatment due to its increased potency and non-invasiveness compared to conventional therapies. Active-targeted delivery of photosensitizers (PSs) is a mainstay strategy to significantly reduce its off-target toxicity and enhance its phototoxic efficacy. The anti-melanoma inhibitory activity (MIA) antibody is a targeting biomolecule that can be integrated into a nanocarrier system to actively target melanoma cells due to its specific binding to MIA antigens that are highly expressed on the surface of melanoma cells. Gold nanoparticles (AuNPs) are excellent nanocarriers due to their ability to encapsulate a variety of therapeutics, such as PSs, and their ability to bind with targeting moieties for improved bioavailability in cancer cells. Hence, we designed a nanobioconjugate (NBC) composed of zinc phthalocyanine tetrasulfonic acid (ZnPcS4), AuNPs and anti-MIA Ab to improve ZnPcS4 bioavailability and phototoxicity in two and three-dimensional tumour models. In summary, we demonstrated that this nanobioconjugate showed significant inhibitory effects on both melanoma models due to increased ROS yields and bioavailability of the melanoma cells compared to free ZnPcS4.

[FeIIICl(TMPPH2)][FeIIICl4]2: A Stand-Alone Molecular Nanomedicine That Induces High Cytotoxicity by Ferroptosis

Developing clinically meaningful nanomedicines for cancer therapy requires the drugs to be effective, safe, simple, cheap, and easy to store. In the present work, we report that a simple cationic Fe(III)-rich salt of [FeIIICl(TMPPH2)][FeIIICl4]2 (Fe-TMPP) exhibits a superior anticancer performance on a broad spectrum of cancer cell lines, including breast, colorectal cancer, liver, pancreatic, prostate, and gastric cancers, with half maximal inhibitory concentration (IC50) values in the range of 0.098-3.97 μM (0.066-2.68 μg mL-1), comparable to the best-reported medicines. Fe-TMPP can form stand-alone nanoparticles in water without the need for extra surface modification or organic-solvent-assisted antisolvent precipitation. Critically, Fe-TMPP is TME-responsive (TME = tumor microenvironment), and can only elicit its function in the TME with overexpressed H2O2, converting H2O2 to the cytotoxic •OH to oxidize the phospholipid of the cancer cell membrane, causing ferroptosis, a programmed cell death process of cancer cells.

Collision of herbal medicine and nanotechnology: a bibliometric analysis of herbal nanoparticles from 2004 to 2023

BACKGROUND

Herbal nanoparticles are made from natural herbs/medicinal plants, their extracts, or a combination with other nanoparticle carriers. Compared to traditional herbs, herbal nanoparticles lead to improved bioavailability, enhanced stability, and reduced toxicity. Previous research indicates that herbal medicine nanomaterials are rapidly advancing and making significant progress; however, bibliometric analysis and knowledge mapping for herbal nanoparticles are currently lacking. We performed a bibliometric analysis by retrieving publications related to herbal nanoparticles from the Web of Science Core Collection (WoSCC) database spanning from 2004 to 2023. Data processing was performed using the R package Bibliometrix, VOSviewers, and CiteSpace.

RESULTS

In total, 1876 articles related to herbal nanoparticles were identified, originating from various countries, with China being the primary contributing country. The number of publications in this field increases annually. Beijing University of Chinese Medicine, Shanghai University of Traditional Chinese Medicine, and Saveetha University in India are prominent research institutions in this domain. The Journal "International Journal of Nanomedicine" has the highest number of publications. The number of authors of these publications reached 8234, with Yan Zhao, Yue Zhang, and Huihua Qu being the most prolific authors and Yan Zhao being the most frequently cited author. "Traditional Chinese medicine," "drug delivery," and "green synthesis" are the main research focal points. Themes such as "green synthesis," "curcumin," "wound healing," "drug delivery," and "carbon dots" may represent emerging research areas.

CONCLUSIONS

Our study findings assist in identifying the latest research frontiers and hot topics, providing valuable references for scholars investigating the role of nanotechnology in herbal medicine.

FeP-Based Nanotheranostic Platform for Enhanced Phototherapy/Ferroptosis/Chemodynamic Therapy

Ferroptosis is an iron-dependent and lipid peroxides (LPO)-overloaded programmed damage cell death, induced by glutathione (GSH) depletion and glutathione peroxide 4 (GPX4) inactivation. However, the inadequacy of endogenous iron and reactive oxygen species (ROS) restricts the efficacy of ferroptosis. To overcome this obstacle, a near-infrared photo-responsive FeP@PEG NPs is fabricated. Exogenous iron pool can enhance the effect of ferroptosis via the depletion of GSH and further regulate GPX4 inactivation. Generation of ·OH derived from the Fenton reaction is proved by increased accumulation of lipid peroxides. The heat generated by photothermal therapy and ROS generated by photodynamic therapy can enhance cell apoptosis under near-infrared (NIR-808 nm) irradiation, as evidenced by mitochondrial dysfunction and further accumulation of lipid peroxide content. FeP@PEG NPs can significantly inhibit the growth of several types of cancer cells in vitro and in vivo, which is validated by theoretical and experimental results. Meanwhile, FeP@PEG NPs show excellent T2-weighted magnetic resonance imaging (MRI) property. In summary, the FeP-based nanotheranostic platform for enhanced phototherapy/ferroptosis/chemodynamic therapy provides a reliable opportunity for clinical cancer theranostics.

Molecular Nanoarchitectonics of Natural Photosensitizers and Their Derivatives Nanostructures for Improved Photodynamic Therapy

Natural photosensitizers (PSs) and their derivatives have drawn ever-increasing attention in photodynamic therapy (PDT) for their wild range of sources, desirable biocompatibility, and good photosensitivity. Nevertheless, many factors such as poor solubility, high body clearance rate, limited tumor targeting ability, and short excitation wavelengths severely hinder their applications in efficient PDT. In recent years, fabricating nanostructures by utilizing molecular assembly technique is proposed to solve these problems. This technique is easy to put into effect, and the assembled nanostructures could improve the physical properties of the PSs so as to meet the requirement of PDT. In this concept, we focus on the construction of natural PSs and their derivatives nanostructures through molecular assembly technique to enhance PDT efficacy (Figure 1). Furthermore, current challenges and future perspectives of natural PSs and their derivatives for efficient PDT are discussed.

Ferroptosis boosted oral cancer photodynamic therapy by carrier-free Sorafenib-Ce6 self-assembly nanoparticles

Oral cancer is a disease with high morbidity and mortality worldwide and greatly impacts the quality of life, especially in patients with advanced stages. Photodynamic therapy (PDT) is one of the most effective clinical treatments for oral cancers. However, most clinically applied photosensitizers have several deficiencies, including oxygen dependence, poor aqueous solubility, and a lack of tumor-targeting ability. Herein, the carrier-free multifunctional Sorafenib (Sor), chlorin e6 (Ce6), and Fe3+ self-assembly co-delivery nanoparticles (Sor-Ce6 NPs) were constructed via combining a ferroptosis inducer Sor and a photosensitizer Ce6 for synergetic therapy. The as-synthesized Sor-Ce6 NPs presented excellent colloidal stability and water dispersity with good in vivo tumor-targeting ability. More significantly, the low dose of Sor-Ce6 NPs had little dark toxicity but produced significantly enhanced ROS and supplied O2 sustainably to increase phototoxicity through ferroptosis pathway. Notably, the Sor-Ce6 NPs showed significantly higher in vitro and in vivo anti-tumor efficacy than the Sor/Ce6 mixture due to the improvement of cellular uptake and the incorporation of foreign Fe ions in the system, which also confer the T1 magnetic resonance-guided imaging ability to the formed Sor-Ce6 NPs. Our study demonstrates a promising self-assembled strategy for overcoming hypoxia-related PDT resistance for oral cancer treatment.

Photodynamic Therapy Combined with Ferroptosis Is a Synergistic Antitumor Therapy Strategy

Ferroptosis is a programmed death mode that regulates redox homeostasis in cells, and recent studies suggest that it is a promising mode of tumor cell death. Ferroptosis is regulated by iron metabolism, lipid metabolism, and intracellular reducing substances, which is the mechanism basis of its combination with photodynamic therapy (PDT). PDT generates reactive oxygen species (ROS) and 1O2 through type I and type II photochemical reactions, and subsequently induces ferroptosis through the Fenton reaction and the peroxidation of cell membrane lipids. PDT kills tumor cells by generating excessive cytotoxic ROS. Due to the limited laser depth and photosensitizer enrichment, the systemic treatment effect of PDT is not good. Combining PDT with ferroptosis can compensate for these shortcomings. Nanoparticles constructed by photosensitizers and ferroptosis agonists are widely used in the field of combination therapy, and their targeting and biological safety can be improved through modification. These nanoparticles not only directly kill tumor cells but also further exert the synergistic effect of PDT and ferroptosis by activating antitumor immunity, improving the hypoxia microenvironment, and inhibiting the tumor angiogenesis. Ferroptosis-agonist-induced chemotherapy and PDT-induced ablation also have good clinical application prospects. In this review, we summarize the current research progress on PDT and ferroptosis and how PDT and ferroptosis promote each other.

Ferroptosis as a potential target for cancer therapy

Ferroptosis is a recently discovered essential type of cell death that is mainly characterized by iron overload and lipid peroxidation. Emerging evidence suggests that ferroptosis is a double-edged sword in human cancer. However, the precise underlying molecular mechanisms and their differential roles in tumorigenesis are unclear. Therefore, in this review, we summarize and briefly present the key pathways of ferroptosis, paying special attention to the regulation of ferroptosis as well as its dual role as an oncogenic and as a tumor suppressor event in various human cancers. Moreover, multiple pharmacological ferroptosis activators are summarized, and the prospect of targeting ferroptosis in cancer therapy is further elucidated.

Nanoparticle-mediated synergistic anticancer effect of ferroptosis and photodynamic therapy: Novel insights and perspectives

Current antitumor monotherapy has many limitations, highlighting the need for novel synergistic anticancer strategies. Ferroptosis is an iron-dependent form of nonapoptotic cell death that plays a pivotal regulatory role in tumorigenesis and treatment. Photodynamic therapy (PDT) causes irreversible chemical damage to target lesions and is widely used in antitumor therapy. However, PDT's effectiveness is usually hindered by several obstacles, such as hypoxia, excess glutathione (GSH), and tumor resistance. Ferroptosis improves the anticancer efficacy of PDT by increasing oxygen and reactive oxygen species (ROS) or reducing GSH levels, and PDT also enhances ferroptosis induction due to the ROS effect in the tumor microenvironment (TME). Strategies based on nanoparticles (NPs) can subtly exploit the potential synergy of ferroptosis and PDT. This review explores recent advances and current challenges in the landscape of the underlying mechanisms regulating ferroptosis and PDT, as well as nano delivery system-mediated synergistic anticancer activity. These include polymers, biomimetic materials, metal organic frameworks (MOFs), inorganics, and carrier-free NPs. Finally, we highlight future perspectives of this novel emerging paradigm in targeted cancer therapies.

Mesenchymal Stem Cell Membrane-Coated TPCS2a-Loaded Nanoparticles for Breast Cancer Photodynamic Therapy

Despite substantial improvements in breast cancer (BC) treatment there is still an urgent need to find alternative treatment options to improve the outcomes for patients with advanced-stage disease. Photodynamic therapy (PDT) is gaining a lot of attention as a BC therapeutic option because of its selectivity and low off-target effects. However, the hydrophobicity of photosensitizers (PSs) impairs their solubility and limits the circulation in the bloodstream, thus representing a major challenge. The use of polymeric nanoparticles (NPs) to encapsulate the PS may represent a valuable strategy to overcome these issues. Herein, we developed a novel biomimetic PDT nanoplatform (NPs) based on a polymeric core of poly(lactic-co-glycolic)acid (PLGA) loaded with the PS meso-tetraphenylchlorin disulfonate (TPCS_2a). TPCS_2a@NPs of 98.89 ± 18.56 nm with an encapsulation efficiency percentage (EE%) of 81.9 ± 7.92% were obtained and coated with mesenchymal stem cells-derived plasma membranes (mMSCs) (mMSC-TPCS_2a@NPs, size of 139.31 ± 12.94 nm). The mMSC coating armed NPs with biomimetic features to impart long circulation times and tumor-homing capabilities. In vitro, biomimetic mMSC-TPCS_2a@NPs showed a decrease in macrophage uptake of 54% to 70%, depending on the conditions applied, as compared to uncoated TPCS_2a@NPs. Both NP formulations efficiently accumulated in MCF7 and MDA-MB-231 BC cells, while the uptake was significantly lower in normal breast epithelial MCF10A cells with respect to tumor cells. Moreover, encapsulation of TPCS_2a in mMSC-TPCS_2a@NPs effectively prevents its aggregation, ensuring efficient singlet oxygen (¹O₂) production after red light irradiation, which resulted in a considerable in vitro anticancer effect in both BC cell monolayers (IC₅₀ < 0.15 µM) and three-dimensional spheroids.

Targeting GSTP1-dependent ferroptosis in lung cancer radiotherapy: Existing evidence and future directions

Radiotherapy is applied in about 70% patients with tumors, yet radioresistance of tumor cells remains a challenge that limits the efficacy of radiotherapy. Ferroptosis, an iron-dependent lipid peroxidation regulated cell death, is involved in the development of a variety of tumors. Interestingly, there is evidence that ferroptosis inducers in tumor treatment can significantly improve radiotherapy sensitivity. In addition, related studies show that Glutathione S-transferase P1 (GSTP1) is closely related to the development of ferroptosis. The potential mechanism of targeting GSTP1 to inhibit tumor cells from evading ferroptosis leading to radioresistance has been proposed in this review, which implies that GSTP1 may play a key role in radiosensitization of lung cancer via ferroptosis pathway.