Ferroptosis In Breast Cancer Cells Research Articles

Oridonin promotes RSL3-induced ferroptosis in breast cancer cells by regulating the oxidative stress signaling pathway JNK/Nrf2/HO-1

The incidence and mortality of breast cancer, the most common malignant tumor among women in the world, are increasing year by year, which greatly threatens women's health. Ferroptosis is an iron and lipid reactive oxygen species (ROS)-dependent process, a novel form of cell death that is distinct from apoptosis and is closely related to the progression of breast cancer. Inducing the occurrence of ferroptosis in tumor cells can effectively block its malignant progress in vivo. Oridonin (ORI), the primary active ingredient extracted from the Chinese herbal medicine Rabdosia rubescens, has been shown to cause glutathione depletion and directly inhibit glutathione peroxidase 4 induced cell death by ferroptosis, but its mechanism of action in breast cancer remains inadequately elucidated. Therefore, we further investigated whether ORI could promote RSL3-induced ferroptosis in breast cancer cells by regulating the oxidative stress pathway JNK/Nrf2/HO-1. In our study, we assessed cell survival of RSL3 and ORI treatment by MTT assay, and found that co-treatment with RSL3 and ORI inhibited cell proliferation, as evidenced by the cloning assay. To investigate the ability of ORI to promote RSL3-induced ferroptosis in breast cancer cells, we measured levels of ROS, malondialdehyde, glutathione, superoxide dismutase, and Fe2+ content. Lipid peroxidation, ROS, and mitochondrial membrane potential levels induced by co-treatment of ORI with RSL3 were reversed by ferrostatin-1, further confirming that the cell death induced by RSL3 and ORI was ferroptosis rather than other programmed cell death modes. Moreover, RSL3 and ORI co-treatment regulated the JNK/Nrf2/HO-1 axis, as demonstrated by western blotting and target activator validation. Our results showed that ORI could enhance the inhibitory effect of RSL3 on breast cancer cells viability via the induction of ferroptosis. Mechanistically, it potentiated RSL3-induced ferroptosis in breast cancer cells by activating the JNK/Nrf2/HO-1 axis. This study provides a theoretical basis for the application of ORI based on the mechanism of ferroptosis, and provides potential natural drug candidates for cancer prevention and treatment.

Abrogating PDK4 activates autophagy-dependent ferroptosis in breast cancer via ASK1/JNK pathway

BackgroundTargeting ferroptosis mediated by autophagy presents a novel therapeutic approach to breast cancer, a mortal neoplasm on the global scale. Pyruvate dehydrogenase kinase isozyme 4 (PDK4) has been denoted as a determinant of breast cancer metabolism. The target of this study was to untangle the functional mechanism of PDK4 in ferroptosis dependent on autophagy in breast cancer.MethodsRT-qPCR and western blotting examined PDK4 mRNA and protein levels in breast cancer cells. Immunofluorescence staining appraised light chain 3 (LC3) expression. Fe (2 +) assay estimated total iron level. Relevant assay kits and C11-BODIPY (591/581) staining evaluated lipid peroxidation level. DCFH-DA staining assayed intracellular reactive oxygen species (ROS) content. Western blotting analyzed the protein levels of autophagy, ferroptosis and apoptosis-signal-regulating kinase 1 (ASK1)/c-Jun N-terminal kinase (JNK) pathway-associated proteins.ResultsPDK4 was highly expressed in breast cancer cells. Knockdown of PDK4 induced the autophagy of breast cancer cells and 3-methyladenine (3-MA), an autophagy inhibitor, countervailed the promoting role of PDK4 interference in ferroptosis in breast cancer cells. Furthermore, PDK4 knockdown activated ASK1/JNK pathway and ASK1 inhibitor (GS-4997) partially abrogated the impacts of PDK4 absence on the autophagy and ferroptosis in breast cancer cells. ConclusionTo sum up, deficiency of PDK4 activated ASK1/JNK pathway to stimulate autophagy-dependent ferroptosis in breast cancer.

Brazilin Actuates Ferroptosis in Breast Cancer Cells via p53/SLC7A11/GPX4 Signaling Pathway.

To investigate the mechanism of induction of ferroptosis by brazilin in breast cancer cells. Breast cancer 4T1 cells were divided into 6 groups: control, brazilin 1/2 half maximal inhibitory concentration (IC50), IC50, 2×IC50, erastin (10 µg/mL) and capecitabine (10 µg/mL) groups. The effect of brazilin on the proliferation of 4T1 cells was detected by cell counting kit-8 assay, and the treatment dose of brazilin was screened. The effect of brazilin on the mitochondrial morphology of 4T1 cells, and the mitochondrial damage was evaluated under electron microscopy. The levels of Fe2+, reactive oxygen species (ROS), malondialdehyde (MDA), glutathione (GSH) and glutathione peroxidase 4 (GPX4) were estimated using various detection kits. The invasion and migration abilities of 4T1 cells were detected by scratch assay and transwell assay. The expressions levels of tumor protein p53, solute carrier family 7 member 11 (SLC7A11), GPX4 and acyl-CoA synthetase long-chain family member 4 (ACSL4) proteins were quantified by Western blot assay. Compared to the control group, the 10 (1/2 IC50), 20 (IC50) and 40 (2×IC50) µg/mL brazilin, erastin, and capecitabine groups showed a significant decrease in the cell survival rate, invasion and migration abilities, GSH, SLC7A11 and GPX4 protein expression levels, and mitochondrial volume and ridge (P<0.05), and a significant increase in the mitochondria membrane density, Fe2+, ROS and MDA levels, and p53 and ACSL4 protein expression levels (P<0.05). Brazilin actuated ferroptosis in breast cancer cells, and the underlying mechanism is mainly associated with the p53/SLC7A11/GPX4 signaling pathway.

SBFI26 induces triple-negative breast cancer cells ferroptosis via lipid peroxidation.

SBFI26, an inhibitor of FABP5, has been shown to suppress the proliferation and metastasis of tumour cells. However, the underlying mechanism by which SBFI26 induces ferroptosis in breast cancer cells remains largely unknown. Three breast cancer cell lines were treated with SBFI26 and CCK-8 assessed cytotoxicity. Transcriptome was performed on the Illumina platform and verified by qPCR. Western blot evaluated protein levels. Malondialdehyde (MDA), total superoxide dismutase (T-SOD), Fe, glutathione (GSH) and oxidized glutathione (GSSG) were measured. SBFI26 induced cell death time- and dose-dependent, with a more significant inhibitory effect on MDA-MB-231 cells. Fer-1, GSH and Vitamin C attenuated the effects but not erastin. RNA-Seq analysis revealed that SBFI26 treatment significantly enriched differentially expressed genes related to ferroptosis. Furthermore, SBFI26 increased intracellular MDA, iron ion, and GSSG levels while decreasing T-SOD, total glutathione (T-GSH), and GSH levels.SBFI26 dose-dependently up-regulates the expression of HMOX1 and ALOX12 at both gene and protein levels, promoting ferroptosis. Similarly, it significantly increases the expression of SAT1, ALOX5, ALOX15, ALOXE3 and CHAC1 that, promoting ferroptosis while downregulating the NFE2L2 gene and protein that inhibit ferroptosis. SBFI26 leads to cellular accumulation of fatty acids, which triggers excess ferrous ions and subsequent lipid peroxidation for inducing ferroptosis.

Cucurbitacin B and erastin co-treatment synergistically induced ferroptosis in breast cancer cells via altered iron-regulating proteins and lipid peroxidation

Ferroptosis is a unique type of cell death which co-exists with elevated iron, suppressed antioxidative function and increased lipid peroxidation. Recent studies have shown that cancer cells are particularly susceptible to the compounds with ferroptotic activities. Cucurbitacin B (CuB) is a triterpenoid with potent biological properties. It has been demonstrated to induce apoptosis and inhibit metastasis in cancer cells. However, the underlying mechanism of the compound is still not fully understood. In the present study, we investigated the ferroptotic effect of CuB in breast cancer cells and evaluated the impact of its combination with erastin, a ferroptosis inducer. In this regard, MTT assay was performed to analyze cell viability. Lipid peroxidation, oxidative stress and the cellular antioxidant capacity were determined with relevant kits. The expression of ferroptotic proteins were analyzed by western blotting. The results indicated that the combined treatment of CuB and erastin activated the ferroptotic pathways significantly in MCF-7 and MDA-MB-231 breast cancer cells. More importantly, the combination treatment altered the expression of iron-related proteins IREB2 and FPN1. In conclusion, this study demonstrated the ferroptotic potential of CuB in breast cancer cells for the first time, and revealed its impact on the expression of iron-regulating proteins.

Compounds targeting ferroptosis in breast cancer: progress and their therapeutic potential.

In recent years, there has been a significant increase in the incidence of Breast cancer (BC), making it the most common cancer among women and a major threat to women's health. Consequently, there is an urgent need to discover new and effective strategies for treating BC. Ferroptosis, a novel form of cell death characterized by the accumulation of iron-dependent lipid reactive oxygen species, has emerged as a distinct regulatory pathway separate from necrosis, apoptosis, and autophagy. It is widely recognized as a crucial factor in the development and progression of cancer, offering a promising avenue for BC treatment. While significant progress has been made in understanding the mechanisms of ferroptosis in BC, drug development is still in its early stages. Numerous compounds, including phytochemicals derived from dietary sources and medicinal plants, as well as synthetic drugs (both clinically approved medications and laboratory reagents), have shown the ability to induce ferroptosis in BC cells, effectively inhibiting tumor growth. This comprehensive review aims to examine in detail the compounds that target ferroptosis in BC and elucidate their potential mechanisms of action. Additionally, the challenges associated with the clinical application of ferroptosis-inducing drugs are discussed, offering valuable insights for the development of novel treatment strategies for BC.

FOXQ1 inhibits breast cancer ferroptosis and progression via the circ_0000643/miR-153/SLC7A11 axis

Dysregulation of ferroptosis is involved in breast cancer progression and therapeutic responses. Inducing ferroptosis can be a potential therapeutic strategy for breast cancer treatment. Forkhead box Q1 (FOXQ1) is an oncogenic transcription factor that highly expressed and related with poor outcomes in various tumors. However, the specific effects of FOXQ1 on ferroptosis in breast cancer is unclear. In this study, we intended to explore the functions and potential mechanisms of FOXQ1 in breast cancer ferroptosis. By CCK-8, colony formation, wound healing, transwell and ferroptosis related assays, we explored the functions of FOXQ1 in breast cancer ferroptosis and progression. Through bioinformatics analysis of public database, luciferase reporter assay, RIP and ChIP assay, we investigated the potential mechanisms of FOXQ1 in breast cancer ferroptosis and progression. We found that FOXQ1 was overexpressed in breast cancer and associated with worse survival. Additionally, inhibition of FOXQ1 suppressed breast cancer ferroptosis and progression. Mechanically, we confirmed that FOXQ1 could bind to the promoter of circ_0000643 host gene to increase the levels of circ_0000643, which could sponge miR-153 and enhance the expression of SLC7A11, leading to reduced cell ferroptosis in breast cancer cells. Targeting the FOXQ1/circ_0000643/miR-153/SLC7A11 axis could be a promising strategy in breast cancer treatment.

Ferroptosis-dependent breast cancer cell-derived exosomes inhibit migration and invasion of breast cancer cells by suppressing M2 macrophage polarization.

Ferroptosis, a novel type of iron-dependent cell death, plays a vital role in breast cancer progression. However, the function of ferroptosis-induced cancer cell-derived exosomes in breast cancer remains unclear. In this study, we attempted to investigate the impact of breast cancer cells-derived exosomes induced by ferroptosis on the polarization of macrophages and the progression of breast cancer. Erastin was used to induce ferroptosis and breast cancer cell-derived exosomes were identified by transmission electron microscopy. Western blot, quantitative reverse transcription PCR, immunofluorescence, flow cytometry, and ELISA were used to determine the role of exosomes in macrophage polarization. Transwell assays were used to detect breast cancer cell migration, and invasion. Our results showed that erastin promoted ferroptosis in breast cancer cells with increased Fe2+ level and ROS production. Breast cancer cell-derived exosomes induced by ferroptosis were successfully isolated and verified to be internalized by macrophages. In addition, ferroptosis-induced breast cancer cell-derived exosomes (Fe-exo) remarkably diminished M2 marker, Arg-1 expression. The ratio of CD206+ macrophages was significantly decreased after Fe-exo treatment. CD206 protein expression and Arg-1 level were dramatically reduced in M2 macrophages incubated by Fe-exo. Moreover, autophagy PCR array showed that the expression of 84 autophagy-related genes were altered after macrophages were incubated by Fe-exo. Furthermore, macrophages incubated by Fe-exo repressed the migration and invasion of breast cancer cells. Ferroptosis-dependent cancer cell-derived exosomes inhibited M2 polarization of macrophages, which in turn inhibited migration and invasion of breast cancer cells. This study provides novel therapeutic strategies for patients with breast cancer.

TMEM189 as a target gene of MiR-499a-5p regulates breast cancer progression through the ferroptosis pathway.

MicroRNA (miR)-499a-5p has been reported to regulate the progression of various tumours. However, the role of miR-499a-5p in breast cancer is unclear. The purpose of this study was to investigate the role and mechanism of miR-499a-5p in breast cancer. The growth effect of miR-499a-5p on breast cancer cells was investigated by the CCK-8 assay, wound healing assay and Transwell invasion assay. The luciferase activity assay was used to verify the downstream targets of miR-499a-5p. The levels of GSH, MDA, and ROS were detected by kits. Quantitative real-time PCR and Western blot were used to determine the expression levels of TMEM189, COX-2, GPX4, and other related genes in cells. miR-499a-5p was down-regulated in MDA-MB-231 cells and was shown to reduced the viability, migration and invasion of MDA-MB-231 cells. Further studies revealed that TMEM189 is a target of miR-499a-5p. miR-499a-5p inhibited breast cancer cell growth by downregulating TMEM189. Furthermore, the down-regulation of TMEM189 promotes ferroptosis in breast cancer cells. The low expression of TMEM189 inhibited the development of breast cancer through the ferroptosis pathway. We have demonstrated for the first time that miR-499a-5p inhibits breast cancer progression by targeting the TMEM189-mediated ferroptosis pathway.

Inducing ferroptosis has the potential to overcome therapy resistance in breast cancer.

Breast cancer is the most common type of malignancy among women. Due to the iron-dependent character of breast cancer cells, they are more sensitive to ferroptosis compared to normal cells. It is possible to reverse tumor resistance by inducing ferroptosis in breast cancer cells, thereby improving tumor treatment outcomes. Ferroptosis is highly dependent on the balance of oxidative and antioxidant status. When ferroptosis occurs, intracellular iron levels are significantly increased, leading to increased membrane lipid peroxidation and ultimately triggering ferroptosis. Ferroptotic death is a form of autophagy-associated cell death. Synergistic use of nanoparticle-loaded ferroptosis-inducer with radiotherapy and chemotherapy achieves more significant tumor suppression and inhibits the growth of breast cancer by targeting cancer tissues, enhancing the sensitivity of cells to drugs, reducing the drug resistance of cancer cells and the toxicity of drugs. In this review, we present the current status of breast cancer and the mechanisms of ferroptosis. It is hopeful for us to realize effective treatment of breast cancer through targeted ferroptosis.

Quercetin Promotes TFEB Nuclear Translocation and Activates Lysosomal Degradation of Ferritin to Induce Ferroptosis in Breast Cancer Cells.

Objective. To investigate the antiproliferative efficacy of quercetin on breast cell lines and its mechanism of ferroptosis regulation. Cells (MCF-7 and MDA-231) were treated with quercetin at 0.1, 1, and 10 μM, respectively. The cell counting kit-8 (CCK-8) assay was applied to assess cell viability, and the intracellular iron level, malondialdehyde (MDA), and carbonylated protein were measured. After treating the cells with quercetin, western blot was applied to determine the level of transcription factor EB (TFEB) and lysosomal-associated membrane protein 1 (LAMP-1) in cells. Meanwhile, western blot was performed to assess the nuclear translocation of TFEB protein in cells. TFEB siRNA and autophagy lysosomal inhibitor, chloroquine, were used to block ferroptosis induced by quercetin. Quercetin induced breast cancer cell death and upregulated the level of iron, MDA, and carbonyl protein in a concentration-dependent manner. Meanwhile, TFEB was highly expressed in the nucleus and lowly expressed in the cytoplasm. The high expression of TFEB promoted the expression of lysosome-related gene LAMP-1, which in turn promoted the degradation of ferritin and the release of ferric ions. The above pharmacodynamic effects of quercetin can be blocked by TFEB siRNA or chloroquine. Quercetin promotes TFEB expression and nuclear transcription, induces the onset of iron death, and thus exerts a pharmacological effect on killing breast cancer cells.

TMEM189 promotes breast cancer through inhibition of autophagy-regulated ferroptosis

Breast cancer is a leading cause of tumor-related death among women around the world, but its pathogenesis is still unclear. Transmembrane protein 189 (TMEM189) is widely expressed in many types of tissues and plays a critical role in tumorigenesis partly through mediating cell death. However, its regulatory function on breast cancer progression and particularly the underlying mechanisms have not been fully understood. In the present study, we found that TMEM189 knockdown significantly reduced the proliferation of breast cancer cells, while its over-expression facilitated the proliferative capacity of tumor cells. The effects of TMEM189 to promote breast cancer were validated in the constructed xenograft mouse models. RNA-sequencing studies subsequently showed that TMEM189 deletion was closely associated with ferroptosis signaling pathway, accompanied with elevated lipid reactive oxygen species (ROS) accumulation, cellular ROS production, malondialdehyde (MDA) and the intracellular iron releases. However, GSH levels in breast cancer cells were highly impeded upon TMEM189 inhibition. Intriguingly, we found that TMEM189 knockdown-induced ferroptotic cell death was considerably abolished after autophagy inhibitor 3-MA co-treatment, as evidenced by the markedly decreased ROS generation and intracellular iron accumulation. Moreover, TMEM189 ablation strongly up-regulated LC3BII and transferrin receptor 1 (TfR1) expression levels in breast cancer cells, whereas down-regulated p62 and GPX4. Importantly, the expression changes of these molecules related to autophagy and ferroptosis were almost diminished in response to 3-MA exposure, along with restored cell proliferation. These findings suggested that TMEM189 could inhibit autophagy to mediate ferroptosis in breast cancer cells. Collectively, all our findings revealed the therapeutic potential of TMEM189 in the treatment of breast cancer.

ESR1 inhibits ionizing radiation-induced ferroptosis in breast cancer cells via the NEDD4L/CD71 pathway

Ferroptosis is the name given to the type of non-apoptotic cell death that is caused by iron accumulation and subsequent lipid peroxidation. However, how ionizing radiation (IR)-induced ferroptosis is regulated in estrogen receptor-positive (ER+) breast cancer cells remains unclear. To attempt to resolve this issue, bioinformatics analysis was performed to evaluate the prognostic value of estrogen receptor 1 (ESR1) in breast cancer tissues. A total of four breast cancer cell lines and an MCF10A non-malignant counterpart were used. Western blotting was used to analyze the levels of protein expression, whereas immunoprecipitation (IP) and ubiquitination experiments were used to test protein binding and ubiquitination levels, respectively. Flow cytometry was subsequently used to analyze cell death and lipid peroxidation levels. The results showed that a high expression level of ESR1 was significantly correlated with poor overall survival in breast cancer. ESR1 knockdown significantly enhanced IR-induced ferroptosis and increased the CD71 protein level. The IP results showed that ESR1 enhanced the binding of the E3 ubiquitin ligase NEDD4L to CD71, promoting the ubiquitination and degradation of CD71, suggesting that CD71 expression was regulated by both ESR1 and NEDD4L. Taken together, the findings in the present study have demonstrated a regulatory relationship between ESR1 and NEDD4L/CD71 in IR-induced ferroptosis. In addition, the ESR1/NEDD4L/CD71 axis may be a potential target for the radiotherapy of breast cancer.

3-Hydroxyquinazoline derivatives, analogues of erastin, induced ferroptosis in breast cancer cells

Introduction. Early malignant tumor detection programs have significantly increased the survival rate of breast cancer patients but the results of drug therapy for this pathology are not always highly effective. Recently discovered iron-dependent cell death, ferroptosis, makes it a promising therapeutic target to reduce the recurrence rates.Objective – to study the induction of ferroptosis in breast cancer cells MCF-7 by quinazoline derivatives synthesized at the Research Institute of Experimental Diagnostics and Therapy of Tumors of the N.N. Blokhin National Medical Research Center of Oncology, Ministry of Health of Russia and to evaluate its antitumor activity on transplanted breast carcinoma Ca-755.Materials and methods. Derivatives of 3-hydroxyquinazoline were obtained by chemical synthesis and have a purity of at least 95 %. In this study 2D cultivation of MCF7 cells, phase-contrast and fluorescence microscopy, and a model of experimental growth of breast carcinoma Ca-755 in female hybrids of immunocompetent mice F1 (C57Bl/6 × DBA/2) were used.Results. Five derivatives of 3-hydroxyquinazoline, analogues of erastine, were studied in this work. The ferroptotic cell death was identified by the level of lipid peroxidation at the concentrations of 1/3 and 1/5 IC50. The level of lipid peroxidation induced by compound 3 was comparable with the activity of erastin in MCF7 cells at both 1/3 and 1/5 of IC50, the activity of the other four quinazoline derivatives was 50–70 % of the activity of erastin. In in vivo experiments at a dose of 30 mg/kg the antitumor efficacy of the compound 3 was higher than that of erastin at the same dose.Conclusion. The data obtained suggest that quinazoline derivative 3 might be considered as a promissisng antitumor agent to treat breast cancer.

The Dual Regulation Effects of ESR1/NEDD4L on SLC7A11 in Breast Cancer Under Ionizing Radiation.

Radiotherapy is one of the most important treatments for breast cancer. Ferroptosis is a recently recognized form of regulated cell death that is characterized by lipid peroxidation. However, whether ionizing radiation (IR) could induce ferroptosis in breast cancer and how it works remain unknown. Bioinformatics analysis were performed to screen ferroptosis-related genes differentially expressed in breast tumor tissue and normal tissue. Then, breast cancer cell lines with different estrogen receptor (ER) phenotypes were used for studies in vitro, including ER-positive (MCF-7 and ZR-75-1) and ER-negative (MDA-MB-231) cells. The dynamic changes of mRNA and protein levels were examined after x-ray of 8 Gy by qRT-PCR and Western blotting, respectively. Immunoprecipitation (IP) was used to explore the interaction between proteins. Luciferase assay was used to analyze the transcriptional regulation effect of ESR1 on SLC7A11. BODIPY C11 and trypan blue dyes were used to determine lipid peroxidation and cell death, respectively. The result showed that the ferroptosis-related gene SLC7A11 was higher in breast cancer tissues compared with normal tissues and associated with poor survival. A positive correlation exists between ESR1 and SLC7A11 expression. ESR1 promoted SLC7A11 expression at the early stage after IR. ESR1/SLC7A11 knockdown significantly enhanced IR-induced ferroptosis in ER-positive cells. At 12 h after IR, the IP data showed the interaction between E3 ubiquitin ligase NEDD4L and SLC7A11 increased, followed by the ubiquitylation and degradation of SLC7A11. Thus, SLC7A11 expression was regulated by both ESR1 and NEDD4L, in opposite ways. For the first time, we elucidated that ESR1 and NEDD4L functioned together after radiation treatment and finally induced ferroptosis in breast cancer cells, which provides novel insight into the guidance of clinical treatment of breast cancer.

Tailored-Made Polydopamine Nanoparticles to Induce Ferroptosis in Breast Cancer Cells in Combination with Chemotherapy.

Ferroptosis is gaining followers as mechanism of selective killing cancer cells in a non-apoptotic manner, and novel nanosystems capable of inducing this iron-dependent death are being increasingly developed. Among them, polydopamine nanoparticles (PDA NPs) are arousing interest, since they have great capability of chelating iron. In this work, PDA NPs were loaded with Fe3+ at different pH values to assess the importance that the pH may have in determining their therapeutic activity and selectivity. In addition, doxorubicin was also loaded to the nanoparticles to achieve a synergist effect. The in vitro assays that were performed with the BT474 and HS5 cell lines showed that, when Fe3+ was adsorbed in PDA NPs at pH values close to which Fe(OH)3 begins to be formed, these nanoparticles had greater antitumor activity and selectivity despite having chelated a smaller amount of Fe3+. Otherwise, it was demonstrated that Fe3+ could be released in the late endo/lysosomes thanks to their acidic pH and their Ca2+ content, and that when Fe3+ was co-transported with doxorubicin, the therapeutic activity of PDA NPs was enhanced. Thus, reported PDA NPs loaded with both Fe3+ and doxorubicin may constitute a good approach to target breast tumors.

Abstract PS18-44: Simvastatin induces ferroptosis in breast cancer cells by inhibiting GPX4 and sensitizes chemotherapy

Abstract Background The incidence of breast cancer ranks the first among female malignant tumors. Although the effect of breast cancer treatment strategies has been very ideal and the mortality rate of breast cancer has decreased, some patients are still not sensitive to these, which eventually leads to rapid recurrence, metastasis and poor prognosis. Ferroptosis is a kind of Regulated cell death, which induced by accumulation of lipid peroxidation products and Reactive Oxygen Species (ROS). It is quite different from apoptosis and autophagy in cell morphological characteristics and biochemical indicators. According to the latest studies, ferroptosis can reduce the activity of GPX4 (Gutathione Peroxidase 4) in cells and accumulate ROS and lipid Peroxidase products through iron metabolism, ROS metabolism, amino acid metabolism and lipid metabolism, etc., thus causing ferroptosis. Ferroptosis is a hotspot in the study of drug resistance and metastasis of breast cancer. Simvastatin is a kind of commonly used oral cholesterol-lowering drugs, belongs to the HMG CoA reductase inhibitors. Some clinical studies have shown that statins can reduce the risk of a variety of cancers, including breast cancer, and the risk of recurrence. Other basic experiment show lipophilic statins have anti-cancer effect. Simvastatin is the most lipophilic of all statins in use. Recent studies have found that simvastatin can be used in combination with docetaxel to enhance the effect of chemotherapy in prostate cancer, but has not been reported in breast cancer. In this study, we investigated whether simvastatin could induce ferroptosis in breast cancer by inhibiting GPX4 and play the role of chemotherapy sensitization in combination with docetaxel. Methods (1) CCK8 assay was used for cell proliferation in vitro by simvastatin and docetaxel in breast cancer cells MDA-MB-231 and MCF-7. (2) The anti-cancer effect of simvastatin in vivo was verified by xenograft experiments in nude mice. (3) GPX4 mRNA and protein levels were detected by qPCR and Western blot. (4) GPXs activity test, ROS level test and MDA level test were used for ferroptosis detection.(5) the expression of ferroptosis-related genes ACSL4, PTGS2 and NOX1 was detected by qPCR.(6) anti-tumor effect of simvastatin combined with docetaxel in breast cancer cells mda-mb-231 and McF-7 was detected in vitro by CCK8 method.(7) By MDA-MB-231 tumor xenograft models surveyed anti-tumor activity of simvastatin and docetaxel. Results CCK8 results showed that simvastatin significantly inhibited cell proliferation in breast cancer cells MDA-MB-231 and MCF-7 (P&amp;lt;0.001), with the IC50 values of MDA-MB-231 was 4.67um and MCF-7 was 81.53um,. In the xenograft experiments of nude mice, it was found that compared with the control group, the tumor volume of the simvastatin group was significantly reduced. In qPCR and Western blot, simvastatin was found to significantly inhibit GPX4 mRNA and protein expression. Compared with the control group, in breast cancer cells MDA-MB-231 and MCF-7, simvastatin can reduce the activity of GPXs and increase the level of ROS and MDA, thus causing ferroptosis in breast cancer cells. qPCR showed that ferroptosis -related gene ACSL4 and PTGS2, which are related to lipid metabolism, and ROS metabolism were significantly increased. In the xenograft experiments of nude mice, it was found that compared with the control group and the single drug group, the tumor volume of simvastatin combined with docetaxel group was significantly reduced. Conclusion Simvastatin can inhibit the proliferation of breast cancer cells both in vivo and in vitro, inhibit the expression of breast cancer cell MDA-MB-231 and MCF-7 GPX4, and induce ferroptosis. Besides, simvastatin sensitizes the effect of docetaxel. Citation Format: Sihong Lu, Nan Shao, Jong Bi, Ying Lin. Simvastatin induces ferroptosis in breast cancer cells by inhibiting GPX4 and sensitizes chemotherapy [abstract]. In: Proceedings of the 2020 San Antonio Breast Cancer Virtual Symposium; 2020 Dec 8-11; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2021;81(4 Suppl):Abstract nr PS18-44.

A Novel Ferroptosis-Related Gene Signature Predicts Overall Survival of Breast Cancer Patients.

Simple SummaryFerroptosis is an iron-dependent cell death which is distinctive from common forms of cell death. Accumulating evidence indicated the close relationship between ferroptosis and numerous human diseases. Regarding breast cancer, a related study indicated that some targeted medicines could induce ferroptosis, furthermore, some basic research found that ferroptosis-related genes were closely related to breast cancer. However, the correlation between ferroptosis-related genes and breast cancer patients’ prognosis remains unknown. We built an 8-ferroptosis-related-gene model to predict breast cancer patients’ prognosis. This model could stratify patients into high- or low-risk groups. Additionally, tumor microenvironment analyses displayed differently enriched immune cells and immune pathways between these two groups. This 8-gene model is believed to be of great value in predicting prognosis for breast cancer patients.Breast cancer is the second leading cause of death in women, thus a reliable prognostic model for overall survival (OS) in breast cancer is needed to improve treatment and care. Ferroptosis is an iron-dependent cell death. It is already known that siramesine and lapatinib could induce ferroptosis in breast cancer cells, and some ferroptosis-related genes were closely related with the outcomes of treatments regarding breast cancer. The relationship between these genes and the prognosis of OS remains unclear. The data of gene expression and related clinical information was downloaded from public databases. Based on the TCGA-BRCA cohort, an 8-gene prediction model was established with the least absolute shrinkage and selection operator (LASSO) cox regression, and this model was validated in patients from the METABRIC cohort. Based on the median risk score obtained from the 8-gene model, patients were stratified into high- or low-risk groups. Cox regression analyses identified that the risk score was an independent predictor for OS. The findings from CIBERSORT and ssGSEA presented noticeable differences in enrichment scores for immune cells and pathways between the abovementioned two risk groups. To sum up, this prediction model has potential to be widely applied in future clinical settings.

Transcriptome Investigation and In Vitro Verification of Curcumin-Induced HO-1 as a Feature of Ferroptosis in Breast Cancer Cells.

Ferroptosis is a form of oxidative cell death and has become a chemotherapeutic target for cancer treatment. Curcumin (CUR), a well-known cancer inhibitor, significantly inhibits the viability of breast cancer cells. Through transcriptomic analysis and flow cytometry experiments, it was found that after 48 hours of treatment of breast cancer cells at its half maximal inhibitory concentration (IC50), curcumin suppressed the viability of cancer cells via induction of ferroptotic death. Use of the ferroptosis inhibitor ferrostatin-1 and the iron chelator deferoxamine rescued cell death induced by curcumin. Furthermore, in subsequent cell validation experiments, the results showed that curcumin caused marked accumulation of intracellular iron, reactive oxygen species, lipid peroxides, and malondialdehyde, while glutathione levels were significantly downregulated. These changes are all manifestations of ferroptosis. Curcumin upregulates a variety of ferroptosis target genes related to redox regulation, especially heme oxygenase-1 (HO-1). Using the specific inhibitor zinc protoporphyrin 9 (ZnPP) to confirm the above experimental results showed that compared to the curcumin treatment group, treatment with ZnPP not only significantly improved cell viability but also reduced the accumulation of intracellular iron ions and other ferroptosis-related phenomena. Therefore, these data demonstrate that curcumin triggers the molecular and cytological characteristics of ferroptosis in breast cancer cells, and HO-1 promotes curcumin-induced ferroptosis.

Highly stable and biocompatible hyaluronic acid-rehabilitated nanoscale MOF-Fe2+ induced ferroptosis in breast cancer cells.

Intracellular amplification of oxidative stress has been proved to be an effective strategy to induce cancer cell death and the Fenton reaction was regarded as a robust way to generate ROS which are the main cause of amplified oxidative stress. However, current Fenton reaction-inducing agents lacked stability in the bio-environment and failed to exert their ideal catalytic performance. We, hereby, designed an Fe2+-based metal-organic framework (MOF) to deliver Fe2+ to cancer cells to trigger the Fenton reaction and produce excessive ROS. The obtained nano-scale MOF that was constructed by ferrous acetate and organic ligands (BDC-NH2) endowed itself with excellent stability in bio-media and pH responsively degraded itself to release Fe2+ in the acid tumor microenvironment. Such a characteristic demonstrated robust capacity to catalyze the Fenton reaction and produce considerable ROS and thus induced distinct Fe2+-mediated cell ferroptosis. Meanwhile, directly exploiting an Fe2+-based MOF to inhibit and kill cancer cells circumvented the potential adverse effects of loading drugs (like the cardiotoxicity of doxorubicin, and the nephrotoxicity and ototoxicity of cisplatin) and proved to be biocompatible in in vivo experiments. More importantly, observations of the in vivo antitumor experiment attested its impressive inhibition on cancer cells and amelioration on the physical health of treated mice. Our study thus presented a novel and biocompatible ferroptosis strategy to be applied in effective clinical cancer therapy.