BHQ-Cyanine-Based "Off-On" Long-Circulating Assembly as a Ferroptosis Amplifier for Cancer Treatment: A Lipid-Peroxidation Burst Device

High Intensity Focused Ultrasound-Driven Nanomotor for Effective Ferroptosis-Immunotherapy of TNBC

The heterogeneity of triple-negative breast cancers (TNBC) remains challenging for various treatments. Ferroptosis, a recently identified form of cell death resulting from the unrestrained peroxidation of phospholipids, represents a potential vulnerability in TNBC. In this study, a high intensity focused ultrasound (HIFU)-driven nanomotor is developed for effective therapy of TNBC through induction of ferroptosis. Through bioinformatics analysis of typical ferroptosis-associated genes in the FUSCCTNBC dataset, gambogic acid is identified as a promising ferroptosis drug and loaded it into the nanomotor. It is found that the rapid motion of nanomotors propelled by HIFU significantly enhanced tumor accumulation and penetration. More importantly, HIFU not only actuated nanomotors to trigger effective ferroptosis of TNBC cells, but also drove nanomotors to activate ferroptosis-mediated antitumor immunity in primary and metastatic TNBC models, resulting in effective tumor regression and prevention of metastases. Overall, HIFU-driven nanomotors show great potential for ferroptosis-immunotherapy of TNBC.

Correlation between ferroptosis and adriamycin resistance in breast cancer regulated by transferrin receptor and its molecular mechanism

Breast cancer is the most prevalent malignant tumor in women. Adriamycin (ADR) is a primary chemotherapy drug, but resistance limits its effectiveness. Ferroptosis, a newly identified cell death mechanism, involves the transferrin receptor (TFRC), closely linked with tumor cells. This study aimed to explore TFRC and ferroptosis's role in breast cancer drug resistance. Bioinformatics analysis showed that TFRC was significantly downregulated in drug-resistant cell lines, and patients with low TFRC expression might demonstrate a poor chemotherapeutic response to standard treatment. High expression of TFRC was positively correlated with most of the ferroptosis-related driver genes. The research findings indicate that ferroptosis markers were higher in breast cancer tissues than in normal ones. In chemotherapy-sensitive cases, Ferrous ion (Fe2+ ) and malondialdehyde (MDA) levels were higher than in resistant cases (all p < .05). TFRC expression was higher in breast cancer than in normal tissue, especially in the sensitive group (all p < .05). Cytological experiments showed increased hydrogen peroxide (H2 O2 ) after ADR treatment in both sensitive and resistant cells, with varying MDA changes (all p < .05). Elevating TFRC increased Fe2+ and MDA in ADR-resistant cells, enhancing their sensitivity to ADR. However, TFRC upregulation combined with ADR increased proliferation and invasiveness in resistant cell lines (all p < .05). In conclusion, ADR resistance to breast cancer is related to the regulation of iron ion-mediated ferroptosis by TFRC. Upregulation of TFRC in ADR-resistant breast cancer cells activates ferroptosis and reverses ADR chemotherapy resistance of breast cancer.

Azulene-Containing Bis(squaraine) Dyes: Design, Synthesis and Aggregation Behaviors

The relationship among chemical structure, physicochemical property and aggregation behavior of organic functional material is an important research topic. Here, we designed and synthesized three bis(squaraine) dyes BSQ1, BSQ2 and BSQ3 through the combination of two kinds of unsymmetrical azulenyl squaraine monomers. Their physicochemical properties were investigated in both molecular and aggregate states. Generally, BSQ1 displayed different assembly behaviors from BSQ2 and BSQ3. Upon fabrication into nanoparticles, BSQ1 tend to form J-aggregates while BSQ2 and BSQ3 tend to form H-aggregates in aqueous medium. When in the form of thin films, three bis(squaraine) dyes all adopted J-aggregation packing modes while only BSQ1 presented the most significant rearrangement of aggregate structures as well as the improvement in the carrier mobilities upon thermal annealing. Our research highlights the discrepancy of aggregation behaviors originating from the molecular structure and surrounding circumstances, providing guidance for the molecular design and functional applications of squaraines.

In situ generation of hybrid alginate hydrogels for enhanced breast tumor ferrotherapy through multiplex magnifying redox imbalances

Ferroptosis has drawn great attention to tumor treatments over the past decade. However, how to specifically boost tumoral redox imbalance by simultaneously superimposing iron-mediated reactive oxygen species and undermining antioxidative pathways at the tumor site is still a significant challenge in ferroptosis-based tumor ferrotherapy. In this study, we designed an in situ generable hydrogel that contains paclitaxel/chlorin e6-loaded iron-based metal-organic framework (Fe-MOF) nanoparticles for enhanced breast tumor ferrotherapy by multiplex magnifying redox imbalance. The polysaccharide sodium alginate can crosslink with tumoral calcium ions to generate a hydrogel patch, which promotes the retention of Fe-MOF and therapeutic molecules. The Fe-MOF holds peroxidase/glutathione oxidase mimicking properties, resulting in OH generation via the Fenton reaction and glutathione consumption. Local ultrasound treatment facilitates the release of therapeutics and stimulates the generation of signet oxygen by activating the sonosensitizer chlorin e6. In the meanwhile, the low-dose paclitaxel reduces tumoral pH value by downregulating the glutaminolysis-related gene (SLC7A11) which in turn enhances the catalytic activity of Fe-MOF and inhibits antioxidative pathways, respectively. Both in vivo and in vitro experiments show that our designed hybrid hydrogels can induce significant ferrotherapeutic effects by augmenting the tumoral oxidative stresses.

Engineering iron-based nanomaterials for breast cancer therapy associated with ferroptosis

Ferroptosis has received increasing attention as a novel nonapoptotic programmed death. Recently, iron-based nanomaterials have been extensively exploited for efficient tumor ferroptosis therapy, as they directly release high concentrations of iron and increase intracellular reactive oxygen species levels. Breast cancer is one of the commonest malignant tumors in women; inhibiting breast cancer cell proliferation through activating the ferroptosis pathway could be a potential new target for patient treatment. Here, we briefly introduce the background of ferroptosis and systematically review the current cancer therapeutic strategies based on iron-based ferroptosis inducers. Finally, we summarize the advantages of these various ferroptosis inducers and shed light on future perspectives. This review aims to provide better guidance for the development of iron-based nanomaterial ferroptosis inducers.

Mechanism of ferroptosis in breast cancer and research progress of natural compounds regulating ferroptosis

Breast cancer is the most prevalent cancer worldwide and its incidence increases with age, posing a significant threat to women's health globally. Due to the clinical heterogeneity of breast cancer, the majority of patients develop drug resistance and metastasis following treatment. Ferroptosis, a form of programmed cell death dependent on iron, is characterized by the accumulation of lipid peroxides, elevated levels of iron ions and lipid peroxidation. The underlying mechanisms and signalling pathways associated with ferroptosis are intricate and interconnected, involving various proteins and enzymes such as the cystine/glutamate antiporter, glutathione peroxidase 4, ferroptosis inhibitor 1 and dihydroorotate dehydrogenase. Consequently, emerging research suggests that ferroptosis may offer a novel target for breast cancer treatment; however, the mechanisms of ferroptosis in breast cancer urgently require resolution. Additionally, certain natural compounds have been reported to induce ferroptosis, thereby interfering with breast cancer. Therefore, this review not only discusses the molecular mechanisms of multiple signalling pathways that mediate ferroptosis in breast cancer (including metastasis, invasion and proliferation) but also elaborates on the mechanisms by which natural compounds induce ferroptosis in breast cancer. Furthermore, this review summarizes potential compound types that may serve as ferroptosis inducers in future tumour cells, providing lead compounds for the development of ferroptosis-inducing agents. Last, this review proposes the potential synergy of combining natural compounds with traditional breast cancer drugs in the treatment of breast cancer, thereby suggesting future directions and offering new insights.

Understanding sorafenib-induced ferroptosis and resistance mechanisms: Implications for cancer therapy

Sorafenib is an important first-line treatment option for liver cancer due to its well-characterized safety profile. While novel first-line drugs may have better efficacy than Sorafenib, they also have limitations such as worse safety and cost-effectiveness. In addition to inducing apoptosis, Sorafenib can also trigger ferroptosis, which has recently been recognized as an immunogenic cell death, unleashing new possibilities for cancer treatment. However, resistance to Sorafenib-induced ferroptosis remains a major challenge. To overcome this resistance and augment the efficacy of Sorafenib, a wide range of nanomedicines has been developed to amplify its pro-ferroptotic effects. This review highlights the mechanisms underlying Sorafenib-triggered ferroptosis and its resistance, and outlines innovative strategies, particularly nanomedicines, to overcome ferroptosis resistance. Moreover, we summarize molecular biomarkers that signify resistance to Sorafenib-mediated ferroptosis, which can assist in predicting therapeutic outcomes.

Tumor microenvironment-initiated lipid redox cycling for efficient triple-negative breast cancer therapy

The use of overwhelming reactive oxygen species (ROS) attack has shown great potential for treating aggressive malignancies; however, targeting this process for further applications is greatly hindered by inefficiency and low selectivity. Here, a novel strategy for ROS explosion induced by tumor microenvironment-initiated lipid redox cycling was proposed, which was developed by using soybean phosphatidylcholine (SPC) to encapsulate lactate oxidase (LOX) and sorafenib (SRF) self-assembled nanoparticles (NPs), named LOX/SRF@Lip. SPC is not only the delivery carrier but an unsaturated lipid supplement for ROS explosion. And LOX catalyzes excessive intratumoral lactate to promote the accumulation of large amounts of H2O2. Then, H2O2 reacts with excessive endogenous iron ions to generate amounts of hydroxyl radical for the initiation of SPC peroxidation. Once started, the reaction will proceed via propagation to form new lipid peroxides (LPO), resulting to devastating LPO explosion and widespread oxidative damage in tumor cells. Furthermore, SRF makes contribution to mass LPO accumulation by inhibiting LPO elimination. Compared to normal tissue, tumor tissue has higher levels of lactate and iron ions. Therefore, LOX/SRF@Lip shows low toxicity in normal tissues, but generates efficient inhibition on tumor proliferation and metastasis, enabling excellent and safe tumor-specific therapy. This work offers new ideas on how to magnify anticancer effect of ROS through rational nanosystem design and tumor-specific microenvironment utilization.

Low androgen levels induce ferroptosis of rat penile cavernous endothelial cells

Background

Endothelial dysfunction caused by low androgen levels in penile tissue can lead to erectile dysfunction. The exact mechanism of endothelial dysfunction has not been thoroughly studied.

Objective

The study sought to verify whether low androgen levels induce ferroptosis of endothelial cells in rat penile tissue.

Methods

Rat penile cavernous endothelial cells (CP-R133) were divided into a no-androgen group (Dihydrotestosterone (DHT): 0 nmol/L), very low-androgen group (DHT: 0.1 nmol/L), low-androgen group (DHT: 1 nmol/L), DHT = 10 nmol/L group, DHT (0 nmol/L) + ferrostatin-1 (Fer-1) group, DHT (0.1 nmol/L) + Fer-1 group, DHT (1 nmol/L) + Fer-1 group, DHT (10 nmol/L) + Fer-1 group. Cell viability, intracellular ferrous ion (Fe2+), malondialdehyde (MDA), GSH into oxidized glutathione (GSSG), reactive oxygen species (ROS), nitric oxide (NO), transferrin receptor 1 protein (TfR1), solute carrier family 7 member 11 (SLC7A11), glutathione peroxidase 4 (GPX4), acyl-CoA synthetase long-chain family member 4 (ACSL4), endothelial nitric oxide synthase (eNOS), and phospho-eNOS (p-eNOS) were detected.

Outcomes

Low androgen levels could induce ferroptosis of rat penile cavernous endothelial cells in vivo by upregulating the expressions of TfR1 and ACSL4 and downregulating the expressions of SLC7A11 and GPX4.

Results

Cell viability, the levels of glutathione (GSH), NO, SLC7A11, GPX4, and p-eNOS/eNOS in the DHT = 0 nmol/L group were lower than those in the other groups (P < .05). The levels of Fe2+, ROS, MDA, GSSG, TfR1, and ACSL4 in the DHT = 0 nmol/L group were higher than those in the other groups (P < .05). Cell viability and the levels of GSH, NO, SLC7A11, GPX4, and p-eNOS/eNOS in the DHT = 1 nmol/L group were lower than those in the DHT (1 nmol/L) + Fer-1 group, DHT = 10 nmol/L group, and DHT (10 nmol/L) + Fer-1 group (P < .05). The levels of Fe2+, ROS, MDA, GSSG, TfR1, and ACSL4 in the DHT = 1 nmol/L group were higher than those in the DHT (1 nmol/L) + Fer-1 group, DHT = 10 nmol/L group, and DHT (10 nmol/L) + Fer-1 group (P < .05).

Clinical Implications

A ferroptosis inhibitor might be a novel drug for treating erectile dysfunction caused by low androgen level.

Strengths and Limitations

The results of this study need to be further confirmed in in vitro and in human studies. Meanwhile, further investigation is needed to clarify whether low androgen levels affect ferroptosis of rat penile cavernous smooth muscle and nerve cells.

Conclusion

Low androgen levels can induce ferroptosis of endothelial cells in rat penile tissue. Inhibition of ferroptosis can reverse endothelial dysfunction caused by low androgen levels.

Inaugurating a novel adjuvant therapy in urological cancers: Ferroptosis

Ferroptosis, a distinctive form of programmed cell death, is involved in numerous diseases with specific characteristics, including certain cell morphology, functions, biochemistry, and genetics, that differ from other forms of programmed cell death, such as apoptosis. Many studies have explored ferroptosis and its associated mechanisms, drugs, and clinical applications in diseases such as kidney injury, stroke, ischemia-reperfusion injury, and prostate cancer. In this review, we summarize the regulatory mechanisms of some ferroptosis inducers, such as enzalutamide and erastin. These are current research focuses and have already been studied extensively. In summary, this review focuses on the use of ferroptosis induction as a therapeutic strategy for treating tumors of the urinary system.

Overexpression of PRDX2 in Adipose-Derived Mesenchymal Stem Cells Enhances the Therapeutic Effect in a Neurogenic Erectile Dysfunction Rat Model by Inhibiting Ferroptosis

Neurogenic erectile dysfunction (NED) is a common and serious complication after pelvic surgery. The clinical translation of adipose-derived mesenchymal stem cell (ADSC) therapies in NED remains a major challenge due to their low survival rate and limited therapeutic effect. Peroxiredoxin 2 (PRDX2) is a member of the peroxidase family that exerts its therapeutic effects by inhibiting oxidative stress (OS) and ferroptosis, and PRDX2 is expected to enhance the therapeutic effect of ADSCs in treating NED. The purpose of this study was to investigate whether PRDX2 could improve the survival of ADSCs and determine whether overexpression of PRDX2 in ADSCs (PRDX2-ADSCs) could enhance the therapeutic effect of NED. This study investigated the potential role of PRDX2-ADSCs through a NED model induced by bilateral cavernous nerve injury (BCNI) and three in vitro models established by H₂O₂-stimulated ADSCs, H₂O₂-stimulated corpus cavernosum smooth muscle cells (CCSMCs), and RSL3-stimulated CCSMCs. We found that PRDX2 could significantly improve the viability of ADSCs by suppressing apoptosis and OS in H₂O₂-stimulated ADSCs. We also found that BCNI triggered ferroptosis of the corpus cavernosum, which was manifested by increased reactive oxygen species (ROS), total iron content, and MDA as well as decreased SOD and GSH. Our results further demonstrated changes in the expression of key proteins (GPX4 and ACSL4) in the ferroptosis pathway, whereas PRDX2-ADSCs ameliorated BCNI-induced erectile dysfunction and ferroptosis of the corpus cavernosum in NED rats. Consistently, PRDX2-ADSCs attenuated OS in H₂O₂-stimulated CCSMCs and inhibited ferroptosis in RSL3-stimulated CCSMCs, as evidenced by the decrease in ROS, total iron content, and MDA and the increase in SOD and GSH together with changes in ferroptosis-related protein (GPX4 and ACSL4) expression. In conclusion, overexpression of PRDX2 in ADSCs enhanced the therapeutic effect in a rat model of neurogenic erectile dysfunction by inhibiting ferroptosis via regulation of the GPX4/ACSL4 axis.

Human umbilical cord mesenchymal stem cells ameliorate erectile dysfunction in rats with diabetes mellitus through the attenuation of ferroptosis

Background

Erectile dysfunction (ED), as one of the most prevalent consequences in male diabetic patients, has a serious impact on men's physical and mental health, and the treatment effect of diabetic mellitus erectile dysfunction (DMED) is often worse. Therefore, the development of a novel therapeutic approach is urgent. As stem cells with high differentiation potential, human umbilical cord mesenchymal stem cells (HUCMSCs) have been widely used in the treatment of diseases in other systems, and are expected to be a promising strategy for the treatment of DMED. In this study, we investigated the role of HUCMSCs in managing erectile function in rat models of type 1 diabetes mellitus (T1DM) and type 2 diabetes mellitus (T2DM) and compared the effects of two different injection methods.

Methods

T1DM and T2DM ED rats were given labelled HUCMSCs by corpus cavernosum injection and tail vein injection, respectively. ICP and MAP were monitored simultaneously by electrical stimulation four weeks after injection to indicate the erectile function of rats. To track the development and colonisation capabilities of stem cells, we performed EdU assay with penile tissue. The histological changes of the penis were observed by hematoxylin–eosin staining, and Masson’s trichrome staining was conducted to evaluate the smooth muscle content and the degree of fibrosis in the rat penis. Then, we employed specific kits to measure the level of NO, cGMP, MDA, SOD and Fe in penis. Electron transmission microscopy was implemented to observe morphology of mitochondria. Besides, western blot and immunofluorescence staining were performed to demonstrate the expression of ferroptosis-related genes.

Results

We found that HUCMSCs improved erectile function in T1DM and T2DM ED rats, with no difference in efficacy between corpus cavernosum injection and tail vein injection. The EdU assay revealed that only a tiny percentage of HUCMSCs colonised the corpus cavernosum, while smooth muscle in the penis expanded and collagen decreased following HUCMSC injection. Moreover, the levels of oxidative stress in the penis of the rats given HUCMSCs were dramatically reduced, as was the tissue iron content. HUCMSCs normalised mitochondrial morphology within corpus cavernosum smooth muscle cells (CCSMCs), which were characteristically altered by high glucose. Furthermore, the expression of ferroptosis inhibitory genes SLC7A11 and GPX4 was obviously elevated in CCSMCs after stem cell management, but the abundances of ACSL4, LPCAT3 and ALOX15 showed the polar opposite tendency.

Conclusions

HUCMSCs can effectively and safely alleviate erectile dysfunction in T1DM and T2DM ED rats, while restoring erectile function by attenuating diabetes-induced ferroptosis in CCSMCs. Additionally, this study provides significant evidence for the development of HUCMSCs as a viable therapeutic strategy for DMED.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13287-022-03147-w.

System Xc−/GSH/GPX4 axis: An important antioxidant system for the ferroptosis in drug-resistant solid tumor therapy

The activation of ferroptosis is a new effective way to treat drug-resistant solid tumors. Ferroptosis is an iron-mediated form of cell death caused by the accumulation of lipid peroxides. The intracellular imbalance between oxidant and antioxidant due to the abnormal expression of multiple redox active enzymes will promote the produce of reactive oxygen species (ROS). So far, a few pathways and regulators have been discovered to regulate ferroptosis. In particular, the cystine/glutamate antiporter (System Xc−), glutathione peroxidase 4 (GPX4) and glutathione (GSH) (System Xc−/GSH/GPX4 axis) plays a key role in preventing lipid peroxidation-mediated ferroptosis, because of which could be inhibited by blocking System Xc−/GSH/GPX4 axis. This review aims to present the current understanding of the mechanism of ferroptosis based on the System Xc−/GSH/GPX4 axis in the treatment of drug-resistant solid tumors.

Targeting Ferroptosis in Colorectal Cancer

Ferroptosis is a unique way of regulating cell death (RCD), which is quite different from other programmed cell deaths such as autophagy. It presents iron overload, accumulation of reactive oxygen species (ROS), and lipid peroxidation. A ferroptotic cell usually has an intact cell structure as well as shrinking mitochondria with decreased or vanishing cristae, concentrated membrane density, and ruptured outer membrane. Recently, increasing investigations have discovered that tumor cells have a much greater iron demand than the normal ones, making them more sensitive to ferroptosis. In other words, ferroptosis may inhibit the progress of the tumor, which can be used in the therapy of tumor patients, especially for those with chemotherapy resistance. Therefore, ferroptosis has become one hot spot in the field of tumor research in recent years. Colorectal cancer (CRC) is one common type of gastrointestinal malignancy. The incidence of CRC appears to have an upward trend year by year since the enhancement of living standards. Although surgery and chemoradiotherapy have largely improved the prognosis of patients with CRC, some patients still appear to have severe adverse reactions and drug resistance. Moreover, much research has verified that ferroptosis has a necessary association with the occurrence and progression of gastrointestinal tumors. In this review, we provide a comprehensive evaluation of the main mechanisms of iron metabolism, lipid metabolism, and amino acid metabolism involved in the occurrence of ferroptosis, as well as the research progress of ferroptosis in CRC.

Development and Verification of a Prognostic Ferroptosis-Related Gene Model in Triple-Negative Breast Cancer

Triple-negative breast cancer (TNBC) is the subtype with the worst prognosis of breast cancer. Ferroptosis, a novel iron-dependent programmed cell death, has an increasingly important role in tumorigenesis and development. However, there is still a lack of research on the relationship between ferroptosis-related genes and the prognosis of TNBC. In this study, we obtained the gene expression profile of TNBC patients and matched clinical data from The Cancer Genome Atlas (TCGA) database. Univariate Cox analysis was used to screen out ferroptosis-related genes associated with TNBC prognosis. Then, the least absolute shrinkage and selection operator (LASSO) regression analysis was employed to establish a prognostic prediction model. A 15-ferroptosis-related gene prognostic prediction model was developed, which classified patients into low-risk (LR) or high-risk (HR) groups. Kaplan-Meier analysis results showed that the prognosis of the LR group was better. The receiver operating characteristic (ROC) curve also confirmed the satisfactory predictive ability of this model. Evaluation of the immune microenvironment of TNBC patients in the HR and LR group suggested these 15 ferroptosis-related genes might affect the prognosis of TNBC by regulating the tumor microenvironment. Our prognostic model can provide a theoretical basis for accurate prognosis prediction of TNBC in clinical practice.

Application of "smart" multifunctional nanoprobes in tumor diagnosis and treatment

Cancer is one of the major diseases that pose a threat to human health and life, especially because it is difficult to diagnose and cure, and recurs easily. In recent years, the development of nanotechnology has provided researchers with new tools for cancer treatment. In particular, nanoprobes that facilitate integrated diagnosis and treatment, high-resolution imaging, and accurate tumor targeting provide new avenues for the early detection and treatment of cancer. This review focuses on the preparations and applications of two kinds of "smart" multifunctional nanoprobes: "Off-On" nanoprobes and "Charge-Reversal" nanoprobes. This review also briefly discusses their mechanisms of action, as they could provide new ideas for the further development of this field.

Multifunctional "ball-rod" Janus nanoparticles boosting Fenton reaction for ferroptosis therapy of non-small cell lung cancer

Ferroptosis is a newly found cell death mechanism, which could bypass apoptosis and reverse multidrug resistance of tumors. However, efficient induction of tumor ferroptosis remains a challenge. In this study, multifunctional "ball-rod" Janus nanoparticles (FTG/L&SMD) were constructed for non-small cell lung cancer (NSCLC) ferroptosis treatment. Protected by tannic acid (TA), FTG/L&SMD maintains long-term function in blood circulation, while modification by 2, 3-dimethylmaleic anhydride (DMMA) confers the FTG/L&SMD with pH-responsive charge reversal. Glucose oxidase (GOD) on FTG/L&SMD catalyzes glucose to produce H₂O₂. Then, iron ion converts H₂O₂ to highly active hydroxyl radicals (OH•) via Fenton reaction, leading to lethal lipid peroxidation (LPO) accumulation. Meanwhile, TA reduces Fe³⁺ to Fe²⁺ to boost Fenton reaction cycle. Sor down-regulated glutathione peroxidase 4 (GPX4) expression in another pathway to induce ferroptosis synergistically. In vitro studies have shown that compared with sorafenib (Sor), FTG/L&SMD not only has more efficient tumor targeting and higher cytotoxicity, but also inhibits tumor migration. In vivo antitumor therapy experiments demonstrate that FTG/L&SMD inhibits tumor growth efficiently, and its toxicity is negligible. In general, FTG/L&SMD can initiate Fenton reaction cycle and reinforced ferroptosis to kill tumor cells, which is a promising anti-tumor nano-drug for NSCLC.

Non-apoptotic cell death-based cancer therapy: Molecular mechanism, pharmacological modulators, and nanomedicine

As an emerging cancer therapeutic target, non-apoptotic cell death such as ferroptosis, necroptosis and pyroptosis, etc., has revealed significant potential in cancer treatment for bypassing apoptosis to enhance the undermined therapeutic efficacy triggered by apoptosis resistance. A variety of anticancer drugs, synthesized compounds and natural products have been proven recently to induce non-apoptotic cell death and exhibit excellent anti-tumor effects. Moreover, the convergence of nanotechnology with functional materials and biomedicine science has provided tremendous opportunities to construct non-apoptotic cell death-based nanomedicine for innovative cancer therapy. Nanocarriers are not only employed in targeted delivery of non-apoptotic inducers, but also used as therapeutic components to induce non-apoptotic cell death to achieve efficient tumor treatment. This review first introduces the main characteristics, the mechanism and various pharmacological modulators of different non-apoptotic cell death forms, including ferroptosis, necroptosis, pyroptosis, autophagy, paraptosis, lysosomal-dependent cell death, and oncosis. Second, we comprehensively review the latest progresses of nanomedicine that induces various forms of non-apoptotic cell death and focus on the nanomedicine targeting different pathways and components. Furthermore, the combination therapies of non-apoptotic cell death with photothermal therapy, photodynamic therapy, immunotherapy and other modalities are summarized. Finally, the challenges and future perspectives in this regard are also discussed.

Multifunctional Nanomaterials for Ferroptotic Cancer Therapy

Patient outcomes from the current clinical cancer therapy remain still far from satisfactory. However, in recent years, several biomedical discoveries and nanotechnological innovations have been made, so there is an impetus to combine these with conventional treatments to improve patient experience and disease prognosis. Ferroptosis, a term first coined in 2012, is an iron-dependent regulated cell death (RCD) based on the production of reactive oxygen species (ROS) and the consequent oxidization of polyunsaturated fatty acids (PUFAs). Many nanomaterials that can induce ferroptosis have been explored for applications in cancer therapy. In this review, we summarize the recent developments in ferroptosis-based nanomaterials for cancer therapy and discuss the future of ferroptosis, nanomedicine, and cancer therapy.

Hypoxia responsive nano-drug delivery system based on angelica polysaccharide for liver cancer therapy

Based on the tumor hypoxic microenvironment and the new programmed cell death mode of combined ferroptosis, an angelica polysaccharide-based nanocarrier material was synthesized. The polymer contains hydrophilic angelica polysaccharide (ASP) that is linked by azobenzene (AZO) linker with ferrocene (Fc), and then the side chain was covalently modified with arachidonic acid (AA). It was postulated that the polymer micelles could work as an instinctive liver targeting drug delivery carrier, owing to the existence of ASP with liver targeting. Moreover, the aim was to engineer hypoxia-responsive polymer micelles which was modified by AA, for selective enhancement of ferroptosis in solid tumor, via diminishing glutathione (GSH) under hypoxia. Finally, we synthesized the amphiphilic polymer micelles AA/ASP-AZO-Fc (AAAF) by self-assembling. The structure of AAAF was confirmed by ¹H-NMR and FT-IR. Then, we exemplified the hydrophobic medication curcumin into polymer micelles AAAF@Cur, which has smooth and regular spheres. In vitro release test affirmed that AAAF@Cur can achieve hypoxia response to drug release. In addition, a series of cell experiments confirmed that hypoxia could enhance cell uptake and effectively improve the proliferation inhibitory activity of HepG2 cells. In conclusion, AAAF, as an effective cell carrier, is expected to develop in sensitizing ferroptosis and anti-tumor.

Biological protein mediated ferroptotic tumor nanotherapeutics

Ferroptosis, a cell death pathway involving iron-related generation of lipid hydroperoxides for achieving incredible tumor suppression, has reignited the hope of chemotherapy in tumor treatment in the past decade. With extensive research studies, various bioactive proteins and cellular pathways have been demonstrated to regulate the occurrence and development of ferroptosis. The gradually established ferroptotic regulatory network is conducive to find effective proteins from a holistic perspective and guides better designs for future ferroptotic tumor therapies. The first section of this review summarizes the recent advances in ferroptotic regulatory mechanisms of proteins and attempts to clarify their latent function in the ferroptotic regulatory network. Second, the existing protein-mediated ferroptotic tumor nanotherapeutic strategies were reviewed, including the protein-mediated iron supplement, cell membrane transporter inhibition, glutathione peroxidase 4 interference, glutathione depletion, bioenzyme-mediated reactive oxygen species generation, heat shock protein inhibition, and tumor-overexpressed protein-triggered drug release for ferroptotic therapy. Finally, the future expectations and challenges of ferroptotic tumor nanotherapeutics for clinical cancer therapy are highlighted.

Ferroptosis in cancer therapeutics: a materials chemistry perspective

Ferroptosis, distinct from apoptosis, is a regulated form of cell death caused by lipid peroxidation that has attracted extensive research interest since it was first defined in 2012. Over the past five years, an increasing number of studies have revealed the close relationship between ferroptosis and materials chemistry, in particular nanobiotechnology, and have concluded that nanotechnology-triggered ferroptosis is an efficient and promising antitumor strategy that provides an alternative therapeutic approach, especially for apoptosis-resistant tumors. In this review, we summarize recent advances in ferroptosis-induced tumor therapy at the intersection of materials chemistry, redox biology, and tumor biology. The biological features and molecular mechanisms of ferroptosis are first outlined, followed by a summary of the feasible strategies to induce ferroptosis using nanomaterials and the applications of ferroptosis in combined tumor therapy. Finally, the existing challenges and future development directions in this emerging field are discussed, with the aim of promoting the progress of ferroptosis-based oncotherapy in materials science and nanoscience and enriching the antitumor arsenal.

Iron-bearing nanoparticles trigger human umbilical vein endothelial cells ferroptotic responses by promoting intracellular iron level

Iron-bearing nanoparticles (IBNPs) were abundant in particulate matter (PM). Due to their high reactivity, IBNPs were considered hazardous to human health, however, their toxic mode-of-action(s) are highly unclear. Ferroptosis is a novel programmed cell death (PCD) that highly associated with intracellular iron. However, the pro-ferroptotic effect of IBNPs has not been characterized. To this end, we ought to investigate whether and how IBNPs (synthetic γ-Fe₂O₃ and Fe₃O₄ NPs were selected as the model compounds) are involved in ferroptosis. We found that human umbilical vein endothelial cells (HUVECs) phagocytized large qualities of γ-Fe₂O₃ and Fe₃O₄ NPs, resulting in increased intracellular iron level. We further observed the disrupted cystine/glutamate reverse transporter (System X_c^-) and glutathione peroxidase 4 (GPX4) signaling in γ-Fe₂O₃ and Fe₃O₄ NPs-challenged HUVECs. γ-Fe₂O₃ and Fe₃O₄ NPs could also cause mitochondrial fusion and fission dysregulation, activate lipid peroxidation and iron metabolism-related genes in a P53-dependent manner. Together, the ferroptotic activity of IBNPs should be acknowledged for the risk assessment of PM associated health effects.

Emerging role of ferroptosis in breast cancer: New dawn for overcoming tumor progression

Breast cancer has become a serious threat to women's health. Cancer progression is mainly derived from resistance to apoptosis induced by procedures or therapies. Therefore, new drugs or models that can overcome apoptosis resistance should be identified. Ferroptosis is a recently identified mode of cell death characterized by excess reactive oxygen species-induced lipid peroxidation. Since ferroptosis is distinct from apoptosis, necrosis and autophagy, its induction successfully eliminates cancer cells that are resistant to other modes of cell death. Therefore, ferroptosis may become a new direction around which to design breast cancer treatment. Unfortunately, the complete appearance of ferroptosis in breast cancer has not yet been fully elucidated. Furthermore, whether ferroptosis inducers can be used in combination with traditional anti- breast cancer drugs is still unknown. Moreover, a summary of ferroptosis in breast cancer progression and therapy is currently not available. In this review, we discuss the roles of ferroptosis-associated modulators glutathione, glutathione peroxidase 4, iron, nuclear factor erythroid-2 related factor-2, superoxide dismutases, lipoxygenase and coenzyme Q in breast cancer. Furthermore, we provide evidence that traditional drugs against breast cancer induce ferroptosis, and that ferroptosis inducers eliminate breast cancer cells. Finally, we put forward prospect of using ferroptosis inducers in breast cancer therapy, and predict possible obstacles and corresponding solutions. This review will deepen our understanding of the relationship between ferroptosis and breast cancer, and provide new insights into breast cancer-related therapeutic strategies.

Regulated lytic cell death in breast cancer

Breast cancer (BC) is a very common cancer among women and one of the primary causes of death in women worldwide. Because BC has different molecular subtypes, the challenges associated with targeted therapy have increased significantly, and the identification of new therapeutic targets has become increasingly urgent. Blocking apoptosis and inhibiting cell death are important characteristics of malignant tumours, including BC. Under adverse conditions, including exposure to antitumour therapy, inhibition of cell death programmes can promote cancerous transformation and the survival of cancer cells. Therefore, inducing cell death in cancer cells is fundamentally important and provides new opportunities for potential therapeutic interventions. Lytic forms of cell death, primarily pyroptosis, necroptosis and ferroptosis, are different from apoptosis owing to their characteristic lysis, that is, the production of cellular components, to guide beneficial immune responses, and the application of lytic cell death (LCD) in the field of tumour therapy has attracted considerable interest from researchers. The latest clinical research results confirm that lytic death signalling cascades involve the BC cell immune response and resistance to therapies used in clinical practice. In this review, we discuss the current knowledge regarding the various forms of LCD, placing a special emphasis on signalling pathways and their implications in BC, which may facilitate the development of novel and optimal strategies for the clinical treatment of BC.

Multifunctional MnO2-based nanoplatform-induced ferroptosis and apoptosis for synergetic chemoradiotherapy

Background: Radiosensitizers that can effectively consume glutathione provide broad prospects for enhancing the efficacy and reducing the side effects of radiotherapy. Aim: To explore the potential role of CuS@mSiO₂@MnO₂ nanocomposites in synergetic chemoradiotherapy. Methods: Nanocomposites were characterized by transmission electron microscopy, UV-Vis spectrometry and dynamic light scattering and were loaded with doxorubicin (DOX). The uptake and biodistribution of nanocomposites were observed by CCK8 assay, MRI and confocal laser scanning microscopy. The radiosensitization effect of nanocomposites and nanocomposites/DOX was assessed both in vitro and in vivo. Results: In vitro application of nanocomposites, with an average diameter of 30 nm and ζ-potential of 13.2 ± 0.4 mV, in combination with radiotherapy, depleted glutathione and induced ferroptosis and apoptosis. Nanocomposites/DOX exhibited tumor cell damage in vivo. Conclusion: We propose that this glutathione-depleting nanosystem could be a radiosensitizer as well as a drug transporter.

The potential application of nanomaterials for ferroptosis-based cancer therapy

Ferroptosis is a new type of programmed cell death, which is expected to become an important strategy of cancer treatment. Traditional strategies for inducing iron death are small molecule inducers based on biological agents. However, because of their poor water solubility, low cell targeting ability and fast metabolismin vivo, it is difficult for molecular drugs to play the long-acting role of ferroptosis induction. With the further study of ferroptosis and development of nanotechnology, nanomaterials have been proved to be more efficient drugs for inducing ferroptosis than those biological drugs. Therein, iron-based nanomaterials can directly release high concentrations of irons and increase reactive oxygen species levels in cells, which produce a better induction effect for ferroptosis. Whereas, it is challenging to differentiate nanoparticle-induced ferroptosis and traditional inducing strategies, elucidate the detailed mechanisms and further classify the synthetical methods of nanomaterials. For better guidance on the development of anticancer strategies, comprehensive summary of the latest developments of ferroptosis related nanomaterials, especially iron-based nanomaterials are in urgent need. In the paper, we summarized the main mechanisms of ferroptosis, highlighted the latest developments of nanomaterials for ferroptosis, and emphasized the advantages of iron-based nanomaterials for ferroptosis. The future prospect in this field was also discussed, paving the way for the related nanomaterials in the clinical cancer therapy.

IR780-based nanomaterials for cancer imaging and therapy

IR780, a small molecule with a strong optical property and excellent photoconversion efficiency following near infrared (NIR) irradiation, has attracted increasing attention in the field of cancer treatment and imaging. This review is focused on different IR780-based nanoplatforms and the application of IR780-based nanomaterials for cancer bioimaging and therapy. Thus, this review summarizes the overall aspects of IR780-based nanomaterials that positively impact cancer biomedical applications.

Co-Administration of iRGD with Sorafenib-Loaded Iron-Based Metal-Organic Framework as a Targeted Ferroptosis Agent for Liver Cancer Therapy

Purpose

Hepatocellular carcinoma (HCC) is one of the most common fatal cancers, with no curative therapy available. The concept of ferroptosis is attracting increasing attention in cancer research. Herein, we describe the use of a nanodevice as an effective strategy for inducing ferroptosis to manage HCC.

Methods

To improve ferroptosis-induced treatment of HCC, we constructed sorafenib (sor)-loaded MIL-101(Fe) nanoparticles (NPs) [MIL-101(Fe)@sor] and evaluated the efficacy of ferroptosis-based HCC therapy after co-administration with the iRGD peptide both in vitro and in vivo.

Results

The prepared MIL-101(Fe) NPs have several promising characteristics including drug-loading, controllable release, peroxidase activity, biocompatibility, and T2 magnetic resonance imaging ability. MIL-101(Fe)@sor NPs significantly induced ferroptosis in HepG2 cells, increased the levels of lipid peroxidation and malondialdehyde, and reduced those of glutathione and glutathione peroxidase 4 (GPX-4). The in vivo results showed that the MIL-101(Fe)@sor NPs significantly inhibited tumor progression and decreased GPX-4 expression levels, with negligible long-term toxicity. Meanwhile, co-administration of MIL-101(Fe)@sor NPs with iRGD significantly accelerated ferroptosis.

Conclusion

Our findings suggest that MIL-101(Fe)@sor NPs co-administered with iRGD are a promising strategy for inducing HCC ferroptosis.

Epigenetic Regulation and Nonepigenetic Mechanisms of Ferroptosis Drive Emerging Nanotherapeutics in Tumor

Currently, traditional cancer therapy still falls far short of expectations. However, a variety of invasive cancers that are resistant to chemotherapy (such as platinum drugs, one of the most applied antineoplastics in clinic) and targeted agents are susceptible to ferroptosis. Ferroptosis is a form of cell death that is driven by cell metabolism and iron-dependent lipid peroxidation. Ferroptosis inducers can eliminate the drug resistance of tumor cells in the mesenchymal state, effectively inhibit the drug resistance of acquired tumor cells, and optimize cancer efficacy. Research based on the epigenetic mechanism of ferroptosis is still in the stage of screening and verifying the regulatory effect, and there is no complete regulatory mechanism network. In this review, we expound on the epigenetic regulation and nonepigenetic mechanisms of ferroptosis and review the epigenetic-based mechanisms of tumor therapy potential and emerging nonepigenetic-based therapies (nanotherapeutics).

Nanomedicine of tyrosine kinase inhibitors

Recent progress in nanomedicine and targeted therapy brings new breeze into the field of therapeutic applications of tyrosine kinase inhibitors (TKIs). These drugs are known for many side effects due to non-targeted mechanism of action that negatively impact quality of patients' lives or that are responsible for failure of the drugs in clinical trials. Some nanocarrier properties provide improvement of drug efficacy, reduce the incidence of adverse events, enhance drug bioavailability, helps to overcome the blood-brain barrier, increase drug stability or allow for specific delivery of TKIs to the diseased cells. Moreover, nanotechnology can bring new perspectives into combination therapy, which can be highly efficient in connection with TKIs. Lastly, nanotechnology in combination with TKIs can be utilized in the field of theranostics, i.e. for simultaneous therapeutic and diagnostic purposes. The review provides a comprehensive overview of advantages and future prospects of conjunction of nanotransporters with TKIs as a highly promising approach to anticancer therapy.

Updates on the applications of iron-based nanoplatforms in tumor theranostics

With the development of biomedicine and materials science, the emerging research of iron-based nanoplatforms (INPs) have provided a bright future for tumor theranostics. Thanks to its excellent biocompatibility and diverse application potential, some INPs have successfully transformed from the laboratory to the clinic and market, making it one of the most successful nanoplatforms. Further investigations associated with its enormous biomedical potential is continuing, and new features of them are being demonstrated. The discovery of ferroptosis therapy opens up new avenue for the applications of INPs in tumor therapy, which is attracting tremendous attention from worldwide. It is well established that some of the INPs are capable of triggering the tumor cell ferroptosis efficiently, accelerating the tumor cell death process. Combined with anti-tumor drugs or other tumor therapy approaches, the INPs-induced ferroptosis are expected to break the bottleneck in the treatment of drug-resistant malignant tumors. In addition, other applications of INPs in tumor theranostics field are still active. Featured with the catalase-like ability, INPs were also well documented to reverse the tumor hypoxia as nanozymes, assisting and enhancing the oxygen-consuming tumor therapy approaches. And the unique magnetic property of INPs endow it with great potential in tumor diagnosis, hyperthermal therapy and target drug delivery. It is of great significance to summarize these new advances. Herein, the latest reports of the applications of INPs in tumor theranostics are classified to expound the trend of its research and development. The featured functions of it will be discussed in detail to provide a new insight. The key issues needing to be addressed and the development prospective will be put forward. We hope that this review will be helpful to understand the ample potential of INPs in tumor theranostics field.

Disulfiram, a Ferroptosis Inducer, Triggers Lysosomal Membrane Permeabilization by Up-Regulating ROS in Glioblastoma

Introduction

Disulfiram (DSF), a drug used in the treatment of alcoholism since 1948, has been shown to have antitumor properties in various tumor types possibly due to the induction of a type cell death, ferroptosis, and the sensitization of cells to chemo- and radiotherapy. In this study, we explored the antitumor properties of DSF in glioblastoma (GBM) and investigated the underlying molecular mechanisms.

Methods

GBM cell lines U251 and LN229 were treated with DSF to assess cytotoxicity and activity of the molecule in vitro. Response of cells to treatment was examined using cell viability, flow cytometry, LDH release assay, immunofluorescence and Western blot analysis.

Results

DSF inhibited cell growth of GBM U251 and LN229 cell lines in vitro in a concentration-dependent manner. Flow cytometry demonstrated that DSF caused G0-G1 growth arrest. DSF treatment led to increased ROS and lipid peroxidation levels relative to controls indicating the involvement of ferroptosis. Furthermore, DSF triggered lysosomal membrane permeabilization (LMP), a critical mechanism promoting cell death, in a ROS-dependent manner. Finally, DSF enhanced radiosensitivity of U251 and LN229 cells.

Discussion

Our findings indicated that DSF induced ferroptosis and LMP and enhanced the radiosensitivity of GBM cells. Therefore, DSF might have efficient antitumor activity in the treatment of human GBM.

Heparanase-driven sequential released nanoparticles for ferroptosis and tumor microenvironment modulations synergism in breast cancer therapy

The normal chemotherapy only induces the intracellular apoptosis pathway to promote primary tumor cells death, while not inhibit tumor metastasis. Herein, we proposed a kind of heparanase (HPSE)-driven sequential released nanoparticles, which modified with β-cyclodextrin (β-CD) grafted heparin (NLC/H(D + F + S) NPs) co-loading with doxorubicin (DOX), ferrocene (Fc), and TGF-β receptor inhibitor (SB431542). NLC/H(D + F + S) NPs successfully inhibited breast cancer metastasis by intracellular and extracellular hybrid mechanism. DOX and Fc loaded in NLC/H(D + F + S) NPs effectively enhanced intracellular ROS level to activate ferroptosis pathway, the enhanced ROS also induced the apoptosis pathway and decreased MMP-9 expression to synergize with ferroptosis for tumor therapy. In extracellular site, SB431542 was sequentially released by HPSE-driven, which blocked tumor metastasis by modulating tumor microenvironment, decreasing TAFs activation, and reducing the secretion of TGF-β. In addition, anti-tumor immune response induced by ferroptosis further strengthened the effect of tumor therapy. Finally, under the help of intracellular and extracellular mechanisms launched by NLC/H(D + F + S) NPs, the satisfactory anti-tumor metastasis effect was obtained in the in vivo anti-tumor assays. Therefore, NLC/H(D + F + S) NPs was a novel dosage regimen for breast cancer therapy through intracellular and extracellular mechanisms, in which ferroptosis induced by ROS played an important role.

Recent advances of sorafenib nanoformulations for cancer therapy: Smart nanosystem and combination therapy

Sorafenib, a molecular targeted multi-kinase inhibitor, has received considerable interests in recent years due to its significant profiles of efficacy in cancer therapy. However, poor pharmacokinetic properties such as limited water solubility, rapid elimination and metabolism lead to low bioavailability, restricting its further clinical application. Over the past decade, with substantial progress achieved in the development of nanotechnology, various types of smart sorafenib nanoformulations have been developed to improve the targetability as well as the bioavailability of sorafenib. In this review, we summarize various aspects from the preparation and characterization to the evaluation of antitumor efficacy of numerous stimuli-responsive sorafenib nanodelivery systems, particularly with emphasis on their mechanism of drug release and tumor microenvironment response. In addition, this review makes great effort to summarize the nanosystem-based combination therapy of sorafenib with other antitumor agents, which can provide detailed information for further synergistic cancer therapy. In the final section of this review, we also provide a detailed discussion of future challenges and prospects of designing and developing ideal sorafenib nanoformulations for clinical cancer therapy.

Tumor Microenvironment-Responsive, Multistaged Liposome Induces Apoptosis and Ferroptosis by Amplifying Oxidative Stress for Enhanced Cancer Therapy

Tumor cells usually display metabolic, genetic, and microenvironment-related alterations, which are beneficial to tumor proliferation, tumor development, and resistance occurrence. Many transporters and enzymes, including ATB^0,+, xCT, and matrix metalloproteinases (MMPs), are involved in the altered cell metabolism and tumor microenvironment and often abnormally upregulated in malignant tumors. Meanwhile, these dysregulated transporters and enzymes provide targets not only for a pharmacological blockage to suppress tumor progress but also for tumor-specific delivery. Although transporters and MMPs have been widely reported for antitumor drug delivery, the feasibility of utilizing two strategies has never been elucidated yet. Herein, we developed an MMP2-activated and ATB^0,+-targeted liposome with doxorubicin and sorafenib (DS@MA-LS) loaded for optimal tumor drug delivery for cancer therapy. DS@MA-LS was designed to prolong blood circulation and deshield the PEG shell from MMP2 cleavage to expose lysine and target overexpressed ATB^0,+ for enhanced tumor distribution and cancer cellular uptake. Besides the anticancer effects of loaded drugs, the endocytosed liposomes could further increase ROS production and suppress the antioxidant system to amplify oxidative stress. As expected, DS@MA-LS displayed enhanced targeted drug delivery to tumor sites with the MMP2-controlled ligand exposure and ATB^0,+-mediated uptake. More importantly, DS@MA-LS successfully inhibited the tumor growth and cancer cell proliferation both in vitro and in vivo by enhancing apoptosis and ferroptosis, which thanks to the increased ROS generation and impaired GSH synthesis synergistically amplified oxidative stress. Our results suggested that the tumor microenvironment-responsive, multistaged nanoplatform, DS@MA-LS, has excellent potential for optimal drug delivery and enhanced cancer treatment.

Sorafenib-Conjugated Zinc Phthalocyanine Based Nanocapsule for Trimodal Therapy in an Orthotopic Hepatocellular Carcinoma Xenograft Mouse Model

Sorafenib, a multitargeted kinase inhibitor, has been reported to elicit a limited therapeutic effect in hepatocellular carcinoma (HCC). Currently, phototherapy, including photodynamic therapy (PDT) and photothermal therapy (PTT), is emerging as a powerful modality for cancer therapy. However, few studies have been reported the effectiveness of the combination of sorafenib with PDT and PTT in HCC. Herein, we designed and synthesized bovine serum albumin (BSA)-coated zinc phthalocyanine (ZnPc) and sorafenib (SFB) nanoparticle (ZnPc/SFB@BSA). The obtained ZnPc/SFB@BSA was able to trigger PDT, PTT, and chemotherapy. After irradiation by a 730 nm light, ZnPc/SFB@BSA significantly suppressed HCC cell proliferation and metastasis while promoted cell apoptosis in vitro. Furthermore, intravenous injection of ZnPc/SFB@BSA led to dramatically reduced tumor growth in an orthotopic xenograft HCC model. More importantly, ZnPc/SFB@BSA presented low toxicity and adequate blood compatibility. Therefore, a combination of ZnPc with sorafenib via BSA-assembled nanoparticle can markedly suppress HCC growth, representing a promising strategy for HCC patients.

Amentoflavone suppresses cell proliferation and induces cell death through triggering autophagy-dependent ferroptosis in human glioma

AIMS

Glioma is the most common type of malignant tumor of the nervous system, and aggressiveness and recurrence are major obstacles for treatment. This study is designed to explore the effects of amentoflavone (AF) on glioma, and to investigate the underlying mechanism of the anti-cancer activities of AF.

METHODS

Cell morphology was recorded under microscopy. Cell viability and cell death ratio were determined by CCK-8 assay and lactate dehydrogenase (LDH) release assay, respectively. Cell cycle progression was assessed by flow cytometry. The levels of iron, MDA (malondialdehyde), lipid ROS, and GSH (reduced glutathione) were assessed by ELISA kit. The cycle-related proteins, ferroptosis-related protein, autophagy-related protein, and the phosphorylation of AMPK, mTOR and p70S6K were analyzed by western blotting. The autophagic flux was observed by transfecting cells with mRFP-GFP-LC3 plasmids. The xenograft murine models were established to analyze the effects of amentoflavone in vivo. The immunohistochemistry assay was performed to analyze the expression of LC3B, Beclin1, ATG5, ATG7, and ferritin heavy chain (FTH).

RESULTS

Our results showed that AF treatment led to reduction in cell viability and cell death. In addition, AF was found to block cell cycle progression in a dose-dependent manner in vitro. Following treatment with AF, the intracellular levels of iron, MDA, and lipid OS were increased, and the levels of GSH and the mitochondrial membrane potential were reduced. In addition, our results showed that AF promoted the autophagic by regulating autophagy-relevant proteins. Our results also showed that the autophagy-induction by AF was associated with regulation of AMPK/mTOR signaling. Mechanistically, the inhibition effects of AF on glioma cell were reversed by DFO, ferreostatin-1 as well as upregulation of FTH. Meanwhile, the FTH levels were increased by compound C and knockdown of ATG7. Moreover, both autophagy inhibitor Baf A1 and knockdown of ATG7 were able to compromising AF-induce ferroptosis and cell death. In vivo, the tumor growth was suppressed by AF in a dose-dependent manner. The level of MDA in the tumor tissue was increased while the level of GSH in tumor tissue was decreased by AF in a dose-dependent manner. Furthermore, the expression of LC3B, Beclin1, ATG5, ATG7 were increased, and the expression of FTH were decreased by AF in a dose-dependent manner in vivo. Conclusion These results demonstrate that AF triggered ferroptosis in autophagy-dependent manner. Our results suggest that AF has the potential to be considered as a novel treatment agent in glioma.

The role of transporters in cancer redox homeostasis and cross-talk with nanomedicines

Tumor cell usually exhibits high levels of reactive oxygen species and adaptive antioxidant system due to the metabolic, genetic, and microenvironment-associated alterations. The altered redox homeostasis can promote tumor progression, development, and treatment resistance. Several membrane transporters are involved in the resetting redox homeostasis and play important roles in tumor progression. Therefore, targeting the involved transporters to disrupt the altered redox balance emerges as a viable strategy for cancer therapy. In addition, nanomedicines have drawn much attention in the past decades. Using nanomedicines to target or reset the redox homeostasis alone or combined with other therapies has brought convincing data in cancer treatment. In this review, we will introduce the altered redox balance in cancer metabolism and involved transporters, and highlight the recent advancements of redox-modulating nanomedicines for cancer treatment.

Utilizing Iron for Targeted Lipid Peroxidation as Anticancer Option of Integrative Biomedicine: A Short Review of Nanosystems Containing Iron

Traditional concepts of life sciences consider oxidative stress as a fundamental process of aging and various diseases including cancer, whereas traditional medicine recommends dietary intake of iron to support physiological functions of the organism. However, due to its strong pro-oxidative capacity, if not controlled well, iron can trigger harmful oxidative stress manifested eventually by toxic chain reactions of lipid peroxidation. Such effects of iron are considered to be major disadvantages of uncontrolled iron usage, although ferroptosis seems to be an important defense mechanism attenuating cancer development. Therefore, a variety of iron-containing nanoparticles were developed for experimental radio-, chemo-, and photodynamic as well as magnetic dynamic nanosystems that alter redox homeostasis in cancer cells. Moreover, studies carried over recent decades have revealed that even the end products of lipid peroxidation, represented by 4-hydroxynonenal (4-HNE), could have desirable effects even acting as kinds of selective anticancer substances produced by non-malignant cells for defense again invading cancer. Therefore, advanced nanotechnologies should be developed for using iron to trigger targeted lipid peroxidation as an anticancer option of integrative biomedicine.