Targeting iron metabolism in osteosarcoma

Tellurium-Doped Bioactive Glass Induces Ferroptosis in Osteosarcoma Cells Regardless of FSP1

Human osteosarcoma (OS) is a rare tumor predominantly affecting long bones and characterized by a poor prognosis. Currently, the first line of intervention consists of the surgical resection of primary tumors combined with radiotherapy and chemotherapy, with a profound impact on the patient's life. Since the surgical removal of OS frequently results in a large resection of bones, the use of biomaterials to sustain the stability of the remaining tissue and to stimulate bone regeneration is challenging. Moreover, residual neoplastic cells might be responsible for tumor recurrence. Here, we explored the potential of tellurium-ion-doped bioactive glass as a novel therapeutic intervention to both eradicate residual malignant cells and promote bone regeneration. Bioactive glass (BAG) has been extensively studied and employed in the field of regenerative medicine due to its osseointegration properties and ability to improve bone tissue regeneration. We found that the incorporation of tellurium (Te) in BAG selectively kills OS cells through ferroptosis while preserving the viability of hBMSCs and stimulating their osteodifferentiation. However, the mechanism of Te toxicity is still unclear: (i) Te-BAG generates lipid-ROS through LOXs activity but not iron overload; (ii) Te-dependent ferroptosis is mediated by GPX4 down-regulation; and (iii) the anti-ferroptotic activity of FSP1 is abrogated, whose expression confers the resistance of OS to the canonical induction of ferroptosis. Overall, our data show that Te-doped bioglass could represent an interesting biomaterial with both pro-ferroptotic activity towards residual cancer cells and pro-osteoregenerative activity.

Iron and cancer: overview of the evidence from population-based studies

Iron is an essential nutrient required for various physiological processes in the body. However, iron imbalance can potentially contribute to initiating and promoting cancer development. Epidemiological studies have investigated the relationship between dietary iron intake and the risk of different types of cancer, yet, not all studies have consistently shown a significant association between dietary iron and cancer risk. Also, studies have shown different effects of dietary heme and non-heme iron intake on cancer risk. While some epidemiological studies suggest a possible link between high dietary iron (mainly heme-iron) intake and increased cancer risk, the evidence remains inconsistent. Moreover, multiple iron biomarkers, which can mirror physiological iron status, have demonstrated varied correlations with the risk of cancer, contingent upon the specific biomarker analyzed and the type of cancer being investigated. Here, we have investigated the current evidence on the potential relationship between dietary iron intake on one hand, and iron biomarkers on the other hand, with the risk of developing different types of cancer, including breast, prostate, lung, pancreatic, colon, colorectal, and liver cancers. Further research is warranted to better understand the complex relationship between dietary iron, physiological iron and cancer development. Future research should account for factors that affect and interact with dietary iron and physiological iron levels, such as genetic susceptibility, overall diet quality, and lifestyle habits.

Research progress on the role of lncRNA, circular RNA, and microRNA networks in regulating ferroptosis in osteosarcoma

Noncoding RNAs (ncRNAs) do not participate in protein-coding. Ferroptosis is a newly discovered form of cell death mediated by reactive oxygen species and lipid peroxidation. Recent studies have shown that ncRNAs such as microRNAs, long noncoding RNAs, circular RNAs, and ferroptosis are involved in the occurrence and development of osteosarcoma (OS). Studies have confirmed that ncRNAs participate in the development of OS by regulating the ferroptosis. However, systematic summary on this topic are still lacking. This review summarises the potential role of ncRNAs in the diagnosis, treatment, drug resistance, and prognosis of OS and the basis for diagnosing, preventing, and treating clinical OS and developing effective drugs. This review summarises the latest research progress on ncRNAs that regulate ferroptosis in OS, attempts to clarify the molecular mechanisms by which ncRNAs regulate ferroptosis in the pathogenesis of OS, and elaborates on the involvement of ferroptosis in OS from the perspective of ncRNAs.

Ferroptosis resistance in cancer cells: nanoparticles for combination therapy as a solution

Ferroptosis is a form of regulated cell death (RCD) characterized by iron-dependent lipid peroxidation. Ferroptosis is currently proposed as one of the most promising means of combating tumor resistance. Nevertheless, the problem of ferroptosis resistance in certain cancer cells has been identified. This review first, investigates the mechanisms of ferroptosis induction in cancer cells. Next, the problem of cancer cell resistance to ferroptosis, as well as the underlying mechanisms is discussed. Recently discovered ferroptosis-suppressing biomarkers have been described. The various types of nanoparticles that can induce ferroptosis are also discussed. Given the ability of nanoparticles to combine multiple agents, this review proposes nanoparticle-based ferroptosis cell death as a viable method of circumventing this resistance. This review suggests combining ferroptosis with other forms of cell death, such as apoptosis, cuproptosis and autophagy. It also suggests combining ferroptosis with immunotherapy.

The Importance and Essentiality of Natural and Synthetic Chelators in Medicine: Increased Prospects for the Effective Treatment of Iron Overload and Iron Deficiency

The supply and control of iron is essential for all cells and vital for many physiological processes. All functions and activities of iron are expressed in conjunction with iron-binding molecules. For example, natural chelators such as transferrin and chelator-iron complexes such as haem play major roles in iron metabolism and human physiology. Similarly, the mainstay treatments of the most common diseases of iron metabolism, namely iron deficiency anaemia and iron overload, involve many iron-chelator complexes and the iron-chelating drugs deferiprone (L1), deferoxamine (DF) and deferasirox. Endogenous chelators such as citric acid and glutathione and exogenous chelators such as ascorbic acid also play important roles in iron metabolism and iron homeostasis. Recent advances in the treatment of iron deficiency anaemia with effective iron complexes such as the ferric iron tri-maltol complex (feraccru or accrufer) and the effective treatment of transfusional iron overload using L1 and L1/DF combinations have decreased associated mortality and morbidity and also improved the quality of life of millions of patients. Many other chelating drugs such as ciclopirox, dexrazoxane and EDTA are used daily by millions of patients in other diseases. Similarly, many other drugs or their metabolites with iron-chelation capacity such as hydroxyurea, tetracyclines, anthracyclines and aspirin, as well as dietary molecules such as gallic acid, caffeic acid, quercetin, ellagic acid, maltol and many other phytochelators, are known to interact with iron and affect iron metabolism and related diseases. Different interactions are also observed in the presence of essential, xenobiotic, diagnostic and theranostic metal ions competing with iron. Clinical trials using L1 in Parkinson's, Alzheimer's and other neurodegenerative diseases, as well as HIV and other infections, cancer, diabetic nephropathy and anaemia of inflammation, highlight the importance of chelation therapy in many other clinical conditions. The proposed use of iron chelators for modulating ferroptosis signifies a new era in the design of new therapeutic chelation strategies in many other diseases. The introduction of artificial intelligence guidance for optimal chelation therapeutic outcomes in personalised medicine is expected to increase further the impact of chelation in medicine, as well as the survival and quality of life of millions of patients with iron metabolic disorders and also other diseases.

Lipid Peroxidation-Related Redox Signaling in Osteosarcoma

Oxidative stress and lipid peroxidation play important roles in numerous physiological and pathological processes, while the bioactive products of lipid peroxidation, lipid hydroperoxides and reactive aldehydes, act as important mediators of redox signaling in normal and malignant cells. Many types of cancer, including osteosarcoma, express altered redox signaling pathways. Such redox signaling pathways protect cancer cells from the cytotoxic effects of oxidative stress, thus supporting malignant transformation, and eventually from cytotoxic anticancer therapies associated with oxidative stress. In this review, we aim to explore the status of lipid peroxidation in osteosarcoma and highlight the involvement of lipid peroxidation products in redox signaling pathways, including the involvement of lipid peroxidation in osteosarcoma therapies.

FSP1 is a predictive biomarker of osteosarcoma cells' susceptibility to ferroptotic cell death and a potential therapeutic target

Human osteosarcoma (OS) is a relatively rare malignancy preferentially affecting long body bones which prognosis is often poor also due to the lack of effective therapies. Clinical management of this cancer basically relies on surgical removal of primary tumor coupled with radio/chemotherapy. Unfortunately, most osteosarcoma cells are resistant to conventional therapy, with the undergoing epithelial-mesenchymal transition (EMT) giving rise to gene expression reprogramming, thus increasing cancer cell invasiveness and metastatic potential. Alternative clinical approaches are thus urgently needed. In this context, the recently described ferroptotic cell death represents an attractive new strategy to efficiently kill cancer cells, since most chemoresistant and mesenchymal-shaped tumors display high susceptibility to pro-ferroptotic compounds. However, cancer cells have also evolved anti-ferroptotic strategies, which somehow sustain their survival upon ferroptosis induction. Indeed, here we show that osteosarcoma cell lines display heterogeneous sensitivity to ferroptosis execution, correlating with the mesenchymal phenotype, which is consistently affected by the expression of the well-known anti-ferroptotic factor ferroptosis suppressor protein 1 (FSP1). Interestingly, inhibiting the activity or expression of FSP1 restores cancer cell sensitivity to ferroptosis. Moreover, we also found that: i) AKRs might also contribute to resistance; ii) NRF2 enhances FSP1 expression upon ferroptosis induction; while iii) p53 contributes to the regulation of FSP1 basal expression in OS cells.In conclusion, FSP1 expression can potentially be used as a valuable predictive marker of OS sensitivity to ferroptosis and as a new potential therapeutic target.

Investigation of the activity of a novel tropolone in osteosarcoma

Osteosarcoma (OS) is a primary malignant bone tumor characterized by frequent metastasis, rapid disease progression, and a high rate of mortality. Treatment options for OS have remained largely unchanged for decades, consisting primarily of cytotoxic chemotherapy and surgery, thus necessitating the urgent need for novel therapies. Tropolones are naturally occurring seven-membered non-benzenoid aromatic compounds that possess antiproliferative effects in a wide array of cancer cell types. MO-OH-Nap is an α-substituted tropolone that has activity as an iron chelator. Here, we demonstrate that MO-OH-Nap activates all three arms of the unfolded protein response (UPR) pathway and induces apoptosis in a panel of human OS cell lines. Co-incubation with ferric chloride or ammonium ferrous sulfate completely prevents the induction of apoptotic and UPR markers in MO-OH-Nap-treated OS cells. MO-OH-Nap upregulates transferrin receptor 1 (TFR1) protein levels, as well as TFR1, divalent metal transporter 1 (DMT1), iron-regulatory proteins (IRP1, IRP2), ferroportin (FPN), and zinc transporter 14 (ZIP14) transcript levels, demonstrating the impact of MO-OH-Nap on iron-homeostasis pathways in OS cells. Furthermore, MO-OH-Nap treatment restricts the migration and invasion of OS cells in vitro. Lastly, metabolomic profiling of MO-OH-Nap-treated OS cells revealed distinct changes in purine and pyrimidine metabolism. Collectively, we demonstrate that MO-OH-Nap-induced cytotoxic effects in OS cells are dependent on the tropolone's ability to alter cellular iron availability and that this agent exploits key metabolic pathways. These studies support further evaluation of MO-OH-Nap as a novel treatment for OS.

Identification of mitochondrial-related signature and molecular subtype for the prognosis of osteosarcoma

Mitochondria play a vital role in osteosarcoma. Therefore, the purpose of this study was to investigate the potential role of mitochondrial-related genes (MRGs) in osteosarcoma. Based on 92 differentially expressed MRGs, osteosarcoma samples were divided into two subtypes using the nonnegative matrix factorization (NMF). Ultimately, a univariate, least absolute shrinkage and selection operator (LASSO), and multivariate Cox analysis were performed to construct a prognostic risk model. The single-sample gene set enrichment analysis assessed the immune infiltration characteristics of osteosarcoma patients. Finally, we identified an osteosarcoma biomarker, malonyl-CoA decarboxylase (MLYCD), which showed downregulation. Osteosarcoma cells proliferation, migration, and invasion were effectively inhibited by the overexpression of MLYCD. Our findings will help us to further understand the molecular mechanisms of osteosarcoma and contribute to the discovery of new diagnostic biomarkers and therapeutic targets.