Amplified Ferroptosis and Apoptosis Facilitated by Differentiation Therapy Efficiently Suppress the Progression of Osteosarcoma

Recent advances in metal-based nanomaterials for malignant bone tumor therapy

Malignant bone tumors seriously affect the quality of life of terminal patients and impose severe economic burdens on social health management owing to the complex pathogenesis, multiresistance, tumor recurrence, and metastasis, for which traditional clinical treatments are difficult to achieve the ideal therapeutic effects. Metal-based nanomaterials have shown great application potential in the treatment of malignant bone tumors because of their unique physicochemical properties, biological activities, and structural features, which have greatly improved their ability to kill malignant bone tumor cells and inhibit bone tumor growth by being designed as carriers, therapeutic agents, and coatings/scaffolds, combined with multimodal treatment methods, which have effectively overcome the problems of low efficacy, easy resistance, metastasis, and recurrence faced by traditional treatment methods. This paper summarizes the latest progress in malignant bone tumor treatment using metal-based nanomaterials through three modes of carriers, therapeutic agents, and coatings/scaffolds in recent years. In addition, the challenges and future development directions of metal-based nanomaterials in treating malignant bone tumors, such as improving biocompatibility, targeting ability, and therapeutic efficacy, were also investigated. Finally, the advantages and prospects of metal-based nanomaterials for the treatment of malignant bone tumors are summarized, providing a helpful reference for future research.

Substrate stiffness modulates osteogenic and adipogenic differentiation of osteosarcoma through PIEZO1 mediated signaling pathway

Most osteosarcoma (OS) cases exhibit poor differentiation at the histopathological level. Disruption of the normal osteogenic differentiation process results in the unregulated proliferation of precursor cells, which is a critical factor in the development of OS. Differentiation therapy aims to slow disease progression by restoring the osteogenic differentiation process of OS cells and is considered a new approach to treating OS. However, there are currently few studies on the mechanism of differentiation of OS, which puts the development of differentiation therapeutic drugs into a bottleneck. Substrate stiffness can regulate differentiation in mesenchymal stem cells. Evidence supports that mesenchymal stem cells and osteoblast precursors are the origin of OS. In this study, we simulated different stiffnesses in vitro to investigate the mechanism of substrate stiffness affecting differentiation of OS. We demonstrate that Piezo type mechanosensitive ion channel component 1 (PIEZO1) plays a critical regulatory role in sensing substrate stiffness in osteogenic and adipogenic differentiation of OS. When OS cells are cultured on the stiff substrate, integrin subunit beta 1 (ITGB1) increases and cooperates with PIEZO1 to promote Yes-Associated Protein (YAP) entering the nucleus, and may inhibit EZH2, thereby inhibiting H3K27me3 and increasing RUNX2 expression, and cells differentiate toward osteogenesis. Our results provide new insights for research on differentiation treatment of OS and are expected to help identify new targets for future drug design.

Manganese-pyrochloric acid photosensitizer nanocomplexes against osteosarcoma: achieving both high activatability and high effectiveness

Introduction

The application of photodynamic therapy (PDT) is limited by unsatisfactory therapeutic efficacy and dose-dependent phototoxicity in clinical settings. Intravenous nano-drug delivery systems (NDDSs) hold promise for enhancing the delivery efficiency of photosensitive drugs, but often result in aggregation-caused quenching (ACQ) effects, preventing site-specific activation.

Methods

We exploited manganese (Mn2+)-pyrochloric acid (PPa) nanocomplexes coordinated using the photosensitizer PPa and metal Mn ion for the treatment of osteosarcoma. The nanocomplexes were precisely co-assembled in water to stably co-deliver Mn2+ and PPa, enabling tumor-specific release and fluorescence recovery.

Results

Following laser irradiation, the activated PPa significantly enhanced the killing effects on primary cancer cells. Additionally, Mn2+ ions activated the cyclic GMP-AMP synthase (cGAS)-stimulator of interferon genes (STING) pathway, promoting maturation of dendritic cells (DCs) and augmenting CD8+-mediated antitumor immune responses.

Discussion

This study advances the on-demand activation of photosensitive drugs and photodynamic immunotherapy toward clinical applicability by exploiting Mn2+-PPa nanocomplexes with high activatability and effectiveness for targeted PDT and immunotherapy.

pH-responsive and nanoenzyme-loaded artificial nanocells relieved osteomyelitis efficiently by synergistic chemodynamic and cuproptosis therapy

Osteomyelitis is an osseous infectious disease that primarily affects children and the elderly with high morbidity and recurrence. The conventional treatments of osteomyelitis contain long-term and high-dose systemic antibiotics with debridements, which are not effective and lead to antibiotic resistance with serious side/adverse effects in many cases. Hence, developing novel antibiotic-free interventions against osteomyelitis (especially antibiotic-resistant bacterial infection) is urgent and anticipated. Here, a bone mesenchymal stem cell membrane-constructed nanocell (CFE@CM) was fabricated against osteomyelitis with the characteristics of acid-responsiveness, hydrogen peroxide self-supplying, enhanced chemodynamic therapeutic efficacy, bone marrow targeting and cuproptosis induction. Notably, mRNA sequencing was applied to unveil the underlying biological mechanisms and found that the biological processes related to copper ion binding, oxidative phosphorylation, peptide biosynthesis and metabolism, etc., were disturbed by CFE@CM in bacteria. This work provided an innovative antibiotic-free strategy against osteomyelitis through copper-enhanced Fenton reaction and distinct cuproptosis, promising to complement the current insufficient therapeutic regimen in clinic.

Recent Progress of Glutathione Peroxidase 4 Inhibitors in Cancer Therapy

Ferroptosis is a novel type of programmed cell death that relies on the build-up of intracellular iron and leads to an increase in toxic lipid peroxides. Glutathione Peroxidase 4 (GPX4) is a crucial regulator of ferroptosis that uses glutathione as a cofactor to detoxify cellular lipid peroxidation. Targeting GPX4 in cancer could be a promising strategy to induce ferroptosis and kill drugresistant cancers effectively. Currently, research on GPX4 inhibitors is of increasing interest in the field of anti-tumor agents. Many reviews have summarized the regulation and ferroptosis induction of GPX4 in human cancer and disease. However, insufficient attention has been paid to GPX4 inhibitors. This article outlines the molecular structures and development prospects of GPX4 inhibitors as novel anticancer agents.

A low-molecular-weight α-glucan from edible fungus Agaricus blazei Murrill activates macrophage TFEB-mediated antibacterial defense to combat implant-associated infection

Implant-associated infection (IAI) is a prevalent and potentially fatal complication of orthopaedic surgery. Boosting antibacterial immunity, particularly the macrophage-mediated response, presents a promising therapeutic approach for managing persistent infections. In this study, we successfully isolated and purified a homogeneous and neutral water-soluble polysaccharide, designated as AM-1, from the edible fungus Agaricus blazei Murrill. Structure analysis revealed that AM-1 (Mw = 3.87 kDa) was a low-molecular-weight glucan characterized by a primary chain of →4)-α-D-Glcp-(1 → and side chains that were linked at the O-6 and O-3 positions. In vivo assays showed that AM-1 effectively attenuated the progression of infection and mitigated infectious bone destruction in IAI mouse models. Mechanistically, AM-1 promotes intracellular autophagy-lysosomal biogenesis by inducing the nuclear translocation of transcription factor EB, finally enhancing the bactericidal capabilities and immune-modulatory functions of macrophages. These findings demonstrate that AM-1 significantly alleviates the progression of challenging IAIs as a presurgical immunoenhancer. Our research introduces a novel therapeutic strategy that employs natural polysaccharides to combat refractory infections.

Shikonin induces ferroptosis in osteosarcomas through the mitochondrial ROS-regulated HIF-1α/HO-1 axis

BACKGROUND

The most common malignant bone tumour is osteosarcoma, which has an unsatisfactory prognosis and unsatisfactory treatment. Ferroptosis shows promise as an effective OS therapy. A substance extracted from the Lithospermum erythrorhizon, Shikonin (SHK), inhibits a number of tumours, including ovarian, gastric, and lung cancers. However, whether SHK induces OS ferroptosis and its mechanisms are not clear.

PURPOSE

Our study is aimed at investigating whether SHK causes ferroptosis and elucidating its molecular mechanism.

METHODS

Cell counting Kit-8, cell cycle and cell apoptosis assay were utilised to assess therapeutic effect of SHK against OS. Normal cells, including H9C2, AML-12 and HK-2, haematoxylin and eosin staining and mice serum biomarker tests were used to assess SHK biosafety. Malondialdehyde (MDA) levels, the glutathione (GSH)/oxidized glutathione (GSSG) ratio, reactive oxygen species (ROS), lipid peroxide (LPO), and intracellular Fe2+ detection, quantitative reverse transcription PCR (qRT-PCR), Western blotting (WB) and rescue experiments were employed to confirm whether SHK induced ferroptosis in OS cells. Molecular docking, cellular thermal shift assay (CETSA), and drug affinity responsive target stability (DARTS) assay were used to evaluate the direct binding between SHK and hypoxia-inducible factor-1α (HIF-1α). Protein stability and degradation analysis, small RNA interference, flow cytometry, qRT-PCR, and WB were used to investigate the molecular mechanism of ferroptosis. In vivo xenografts of nude mouse was used to study the anti-OS effect of SHK.

RESULTS

SHK significantly reduced OS cell viability and induced apoptosis and G2/M arrest. SHK increased intracellular levels of MDA, ROS, LPO, and Fe2+ while simultaneously reducing the GSH/GSSG ratio and GPX4 and SLC7A11 expression. CETSA and DARTS results demonstrated that SHK did not bind targetly to HIF-1α. Instead, mitochondrial ROS (MitoROS) promoted HIF-1α expression, resulting in HO-1 overexpression, excess Fe2+ production, ROS accumulation and GPX depletion, and ferroptosis. Furthermore, inhibition of MitoROS using Mito-TEMPO downregulated HIF-1α/HO-1 axis and mitigated the SHK-induced ferroptosis. In vivo, SHK effectively suppressed OS growth with favourable biosafety, confirming the molecular mechanism underlying SHK-induced ferroptosis in OS.

CONCLUSION

We observe that HIF-1α/HO-1 axis is the crucial factor in SHK-induced OS ferroptosis. Importantly, we demonstrate that HIF-1α is indirectly regulated by MitoROS rather than SHK bound directly to HIF-1α. Our research suggest that SHK is a potential drug candidate for OS treatment and may help in identifying novel therapeutic targets for OS.

Augment of Ferroptosis with Photothermal Enhanced Fenton Reaction and Glutathione Inhibition for Tumor Synergistic Nano-Catalytic Therapy

Introduction

Ferroptosis-driven tumor ablation strategies based on nanotechnology could be achieved by elevating intracellular iron levels or inhibiting glutathione peroxidase 4 (GPX4) activity. However, the intracellular antioxidative defense mechanisms endow tumor cells with ferroptosis resistance capacity. The purpose of this study was to develop a synergistic therapeutic platform to enhance the efficacy of ferroptosis-based tumor therapy.

Methods

In this study, a multifunctional nano-catalytic therapeutic platform (mFeB@PDA-FA) based on chemodynamic therapy (CDT) and photothermal therapy (PTT) was developed to effectively trigger ferroptosis in tumor. In our work, iron-based mesoporous Fe3O4 nanoparticles (mFe3O4 NPs) were employed for the encapsulation of L-buthionine sulfoximine (BSO), followed by the modification of folic acid-functionalized polydopamine (PDA) coating on the periphery. Then, the antitumor effect of mFeB@PDA-FA NPs was evaluated using Human OS cells (MNNG/HOS) and a subcutaneous xenograft model of osteosarcoma.

Results

mFe3O4 harboring multivalent elements (Fe2+/3+) could catalyze hydrogen peroxide (H2O2) into highly cytotoxic ˙OH, while the tumor microenvironment (TME)-responsive released BSO molecules inhibit the biosynthesis of GSH, thus achieving the deactivation of GPX4 and the enhancement of ferroptosis. Moreover, thanks to the remarkable photothermal conversion performance of mFe3O4 and PDA shell, PTT further synergistically enhanced the efficacy of CDT and facilitated ferroptosis. Both in vivo and in vitro experiments confirmed that this synergistic therapy could achieve excellent tumor inhibition effects.

Conclusion

The nanotherapeutic platform mFeB@PDA-FA could effectively disrupted the redox homeostasis in tumor cells for boosting ferroptosis through the combination of CDT, PTT and GSH elimination, which provided a new perspective for the treatment of ferroptosis sensitive tumors.

Tetrahedral Framework Nucleic Acid-Loaded Retinoic Acid Promotes Osteosarcoma Stem Cell Clearance

Metastatic osteosarcoma is a commonly seen malignant tumor in adolescents, with a five year survival rate of approximately 20% and a lack of treatment options. Osteosarcoma cancer stem cells are considered to be important drivers of the metastasis of osteosarcoma, and therefore their clearance is considered a promising strategy for treating metastatic osteosarcoma. In the relevant literature, retinoic acid (ATRA) is considered effective for eliminating osteosarcoma stem cells, but it has some inherent disadvantages, including poor solubility, difficulty in entering cells, and structural instability. Tetrahedral framework nucleic acids (tFNAs) are a type of nanoparticles that can carry small-molecule drugs into cells to exert therapeutic effects. Therefore, we designed and synthesized a nanoparticle named T-ATRA by using tFNAs to load ATRA and studied its effect in a nude mouse model. T-ATRA is more effective than ATRA in the clearance of osteosarcoma stem cells and in inhibiting osteosarcoma cell metastasis via the Wnt signaling pathway, thus prolonging the survival time of nude mice with osteosarcoma.

Ultrasound-triggered and glycosylation inhibition-enhanced tumor piezocatalytic immunotherapy

Nanocatalytic immunotherapy holds excellent potential for future cancer therapy due to its rapid activation of the immune system to attack tumor cells. However, a high level of N-glycosylation can protect tumor cells, compromising the anticancer immunity of nanocatalytic immunotherapy. Here, we show a 2-deoxyglucose (2-DG) and bismuth ferrite co-loaded gel (DBG) scaffold for enhanced cancer piezocatalytic immunotherapy. After the implantation in the tumor, DBG generates both reactive oxygen species (ROS) and piezoelectric signals when excited with ultrasound irradiation, significantly promoting the activation of anticancer immunity. Meanwhile, 2-DG released from ROS-sensitive DBG disrupts the N-glycans synthesis, further overcoming the immunosuppressive microenvironment of tumors. The synergy effects of ultrasound-triggered and glycosylation inhibition enhanced tumor piezocatalytic immunotherapy are demonstrated on four mouse cancer models. A "hot" tumor-immunity niche is produced to inhibit tumor progress and lung metastasis and elicit strong immune memory effects. This work provides a promising piezocatalytic immunotherapy for malignant solid tumors featuring both low immunogenicity and high levels of N-glycosylation.

Biointerface-Engineered Hybrid Nanovesicles for Targeted Reprogramming of Tumor Microenvironment

The tumor microenvironment (TME) of typical tumor types such as triple-negative breast cancer is featured by hypoxia and immunosuppression with abundant tumor-associated macrophages (TAMs), which also emerge as potential therapeutic targets for antitumor therapy. M1-like macrophage-derived exosomes (M1-Exos) have emerged as a promising tumor therapeutic candidate for their tumor-targeting and macrophage-polarization capabilities. However, the limited drug-loading efficiency and stability of M1-Exos have hindered their effectiveness in antitumor applications. Here, a hybrid nanovesicle is developed by integrating M1-Exos with AS1411 aptamer-conjugated liposomes (AApt-Lips), termed M1E/AALs. The obtained M1E/AALs are loaded with perfluorotributylamine (PFTBA) and IR780, as P-I, to construct P-I@M1E/AALs for reprogramming TME by alleviating tumor hypoxia and engineering TAMs. P-I@M1E/AAL-mediated tumor therapy enhances the in situ generation of reactive oxygen species, repolarizes TAMs toward an antitumor phenotype, and promotes the infiltration of T lymphocytes. The synergistic antitumor therapy based on P-I@M1E/AALs significantly suppresses tumor growth and prolongs the survival of 4T1-tumor-bearing mice. By integrating multiple treatment modalities, P-I@M1E/AAL nanoplatform demonstrates a promising therapeutic approach for overcoming hypoxic and immunosuppressive TME by targeted TAM reprogramming and enhanced tumor photodynamic immunotherapy. This study highlights an innovative TAM-engineering hybrid nanovesicle platform for the treatment of tumors characterized by hypoxic and immunosuppressive TME.

ANK1 inhibits malignant progression of osteosarcoma by promoting ferroptosis

PURPOSE

Osteosarcoma (OS) is a primary bone tumor with high malignancy and poor prognosis. Ferroptosis plays a crucial role in OS. This study aimed to evaluate the effects of Ankyrin 1 (ANK1) on OS and to investigate its specific mechanisms.

METHODS

Microarray datasets related to "osteosarcoma" were selected for this study. Relevant hub genes in OS were identified through bioinformatics analysis. Transfected U-2OS and MG-63 cells were used for in vitro experiments. The effects of ANK1 overexpression on cell viability, migration, and invasion were determined through CCK-8, wound healing, and transwell assays. An OS mouse model was established for the in vivo experiments. Hematoxylin-eosin staining and immunohistochemistry were conducted to observe the histological effects of ANK1 overexpression on mouse tumors. TUNEL staining was performed to evaluate apoptosis in mouse.

RESULTS

There were 159 common differentially expressed genes in the GSE16088 and GSE19276 datasets. The hub genes ANK1, AHSP, GYPB, GYPA, KEL, and ALAS2 were identified. Pan-cancer analysis verified that ANK1 was closely associated with cancer prognosis and immune infiltration. Furthermore, ANK1 overexpression inhibited the proliferation, migration, and invasion of OS cells and promoted ferroptosis, while ferroptosis inhibitor (fer-1) weakened these effects. Moreover, ANK1 overexpression suppressed tumor growth, promoted apoptosis, reduced the number of Ki67 positive cells, and elevated the number of caspase-3 positive cells in vivo.

CONCLUSIONS

ANK1 is a prognosis biomarker of OS that can alleviate the progression of OS by promoting ferroptosis.

Tumor Microenvironment-Specific Driven Nanoagents for Synergistic Mitochondria Damage-Related Immunogenic Cell Death and Alleviated Immunosuppression

Despite significant breakthroughs in immunotherapy, the limitations of inadequate immune stimulation and stubborn immune resistance continue to present opportunities and challenges. Therefore, a two-pronged approach, encompassing the activation of immunogenic cell death (ICD) and blocking the indoleamine 2,3-dioxygenase (IDO)-mediated pathway, is devised to elicit systemic anti-tumor immunity and alleviate immunosuppression. Herein, a tumor microenvironment (TME)-specific driven nanoagent is composed of a tetrasulfide bond-bridged mesoporous silica layer (MON) coated up-conversion nanoparticles as a nano-carrier, combines Fe2+, curcumin, and indoximod for operating chemodynamic therapy/chemotherapy/immunotherapy. The consumption of glutathione (GSH) caused by MON degradation, the Fenton reaction of Fe2+, and curcumin triggering mitochondrial damage collectively exacerbate the oxidative stress, leading to a violent immunoreaction and reversal of the immunosuppressive TME through a combination of IDO-inhibitors. Meanwhile, upconversion luminescence (UCL) imaging serves as a significant guiding tool for drug delivery and the treatment of nanoagents. In vivo and in vitro experiment results demonstrate that the nanosystem not only effectively inhibits the growth of primary tumors but also induces immune priming and memory effects to reject re-challenged tumors. The strategy as a complementary approach displays great potential for future immunotherapy along with other multimodal treatment modes.

Decoding the "Fingerprint" of Implant Materials: Insights into the Foreign Body Reaction

Foreign body reaction (FBR) is a prevalent yet often overlooked pathological phenomenon, particularly within the field of biomedical implantation. The presence of FBR poses a heavy burden on both the medical and socioeconomic systems. This review seeks to elucidate the protein "fingerprint" of implant materials, which is generated by the physiochemical properties of the implant materials themselves. In this review, the activity of macrophages, the formation of foreign body giant cells (FBGCs), and the development of fibrosis capsules in the context of FBR are introduced. Additionally, the relationship between various implant materials and FBR is elucidated in detail, as is an overview of the existing approaches and technologies employed to alleviate FBR. Finally, the significance of implant components (metallic materials and non-metallic materials), surface CHEMISTRY (charge and wettability), and physical characteristics (topography, roughness, and stiffness) in establishing the protein "fingerprint" of implant materials is also well documented. In conclusion, this review aims to emphasize the importance of FBR on implant materials and provides the current perspectives and approaches in developing implant materials with anti-FBR properties.

Impact of physicochemical properties on biological effects of lipid nanoparticles: Are they completely safe

Lipid nanoparticles (LNPs) are promising materials and human-use approved excipients, with manifold applications in biomedicine. Researchers have tended to focus on improving the pharmacological efficiency and organ targeting of LNPs, while paid relatively less attention to the negative aspects created by their specific physicochemical properties. Here, we discuss the impacts of LNPs' physicochemical properties (size, surface hydrophobicity, surface charge, surface modification and lipid composition) on the adsorption-transportation-distribution-clearance processes and bio-nano interactions. In addition, since there is a lack of review emphasizing on toxicological profiles of LNPs, this review outlined immunogenicity, inflammation, hemolytic toxicity, cytotoxicity and genotoxicity induced by LNPs and the underlying mechanisms, with the aim to understand the properties that underlie the biological effects of these materials. This provides a basic strategy that increased efficacy of medical application with minimized side-effects can be achieved by modulating the physicochemical properties of LNPs. Therefore, addressing the effects of physicochemical properties on toxicity induced by LNPs is critical for understanding their environmental and health risks and will help clear the way for LNPs-based drugs to eventually fulfill their promise as a highly effective therapeutic agents for diverse diseases in clinic.

Ferroptosis defense mechanisms: The future and hope for treating osteosarcoma

Currently, challenges such as chemotherapy resistance, resulting from preoperative and postoperative chemotherapy, postoperative recurrence, and poor bone regeneration quality, are becoming increasingly prominent in osteosarcoma (OS) treatment. There is an urgent need to find more effective ways to address these issues. Ferroptosis is a novel form of iron-dependent programmed cell death, distinct from other forms of cell death. In this paper, we summarize how, through the three major defense systems of ferroptosis, not only can substances from traditional Chinese medicine, antitumor drugs, and nano-drug carriers induce ferroptosis in OS cells, but they can also be combined with immunotherapy, differentiation therapy, and other treatment modalities to significantly enhance chemotherapy sensitivity and inhibit tumor growth. Thus, ferroptosis holds great potential in treating OS, offering more choices and possibilities for future clinical interventions.

Competing endogenous RNA networks and ferroptosis in cancer: novel therapeutic targets

As a newly identified regulated cell death, ferroptosis is a metabolically driven process that relies on iron and is associated with polyunsaturated fatty acyl peroxidation, elevated levels of reactive oxygen species (ROS), and mitochondrial damage. This distinct regulated cell death is dysregulated in various cancers; activating ferroptosis in malignant cells increases cancer immunotherapy and chemoradiotherapy responses across different malignancies. Over the last decade, accumulating research has provided evidence of cross-talk between non-coding RNAs (ncRNAs) and competing endogenous RNA (ceRNA) networks and highlighted their significance in developing and progressing malignancies. Aside from pharmaceutical agents to regulate ferroptosis, recent studies have shed light on the potential of restoring dysregulated ferroptosis-related ceRNA networks in cancer treatment. The present study provides a comprehensive and up-to-date review of the ferroptosis significance, ferroptosis pathways, the role of ferroptosis in cancer immunotherapy and chemoradiotherapy, ceRNA biogenesis, and ferroptosis-regulating ceRNA networks in different cancers. The provided insights can offer the authorship with state-of-the-art findings and future perspectives regarding the ferroptosis and ferroptosis-related ceRNA networks and their implication in the treatment and determining the prognosis of affected patients.

Oridonin-induced ferroptosis and apoptosis: a dual approach to suppress the growth of osteosarcoma cells

BACKGROUND

Osteosarcoma (OS) is one of the most common aggressive bone malignancy tumors in adolescents. With the application of new chemotherapy regimens, finding new and effective anti-OS drugs to coordinate program implementation is urgent for the patients of OS. Oridonin had been proved to mediate anti-tumor effect on OS cells, but its mechanism has not been fully elucidated.

METHODS

The effects of oridonin on the viability, clonal formation and migration of 143B and U2OS cells were detected by CCK-8, colony formation assays and wound-healing test. Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis was used to explore the mechanism of oridonin on OS. Western blot (WB), real-time quantitative PCR (qRT-PCR) were used to detect the expression levels of apoptosis and ferroptosis-relative proteins and genes. Annexin V-FITC apoptosis detection kit and flow cytometry examination were used to detect the level of apoptosis. Iron assay kit was used to evaluate the relative Fe2+ content. The levels of mitochondrial membrane potential and lipid peroxidation production was determined by mitochondrial membrane potential detection kit and ROS assay kit.

RESULTS

Oridonin could effectively inhibit the survival, clonal formation and metastasis of OS cells. The KEGG results indicated that oridonin is associated with the malignant phenotypic signaling pathways of proliferation, migration, and drug resistance in OS. Oridonin was capable of inhibiting expressions of BAX, cl-caspase3, SLC7A11, GPX4 and FTH1 proteins and mRNA, while promoting the expressions of Bcl-2 and ACSL4 in 143B and U2OS cells. Additionally, we found that oridonin could promote the accumulation of reactive oxygen species (ROS) and Fe2+ in OS cells, as well as reduce mitochondrial membrane potential, and these effects could be significantly reversed by the ferroptosis inhibitor ferrostatin-1 (Fer-1).

CONCLUSION

Oridonin can trigger apoptosis and ferroptosis collaboratively in OS cells, making it a promising and effective agent for OS therapy.

IOX1 epigenetically enhanced photothermal therapy of 3D-printing silicene scaffolds against osteosarcoma with favorable bone regeneration

Osteosarcoma (OS) is the third most common malignancy in adolescence. Currently, the treatments of OS confront great obstacles of tumor recurrence and critical bone defects after surgery, severely affecting the survival rates and living qualities of patients. Hence, it is urged to develop distinct biomaterials with both efficient tumor therapeutic and osteogenic functions. Although photothermal therapy (PTT) has aroused expanding interest, characterizing negligible invasiveness and high spatiotemporal adjustment, few studies discussed its drawbacks, such as thermal injury to adjacent normal tissue and exceeded laser power density, implying that focusing on sensitizing OS to PTT instead of simply elevating the laser power density may be a fresh way to enhance the PTT efficacy and attenuate the side/adverse effects. Herein, we successfully constructed 3D-printing silicene bioactive glass scaffolds with preferable PTT efficacy at the second near-infrared (NIR-II) biowindow and outstanding osteogenic biofunctions owing to the release of bioactive elements during degradation. Impressively, a histone demethylase inhibitor, IOX1, was introduced before PTT to sensitize OS to thermal therapy and minimize the side/adverse effects. This work offered a distinctive paradigm for optimizing the PTT efficacy of osteogenic scaffolds against OS with epigenetic modulation agents.