Project description:Ferroptosis is a newly identified form of regulated cell death (RCD) characterized by the iron-dependent lipid reactive oxygen species (ROS) accumulation, but its mechanism in gliomas remains elusive. Acyl-coenzyme A (CoA) synthetase long-chain family member 4 (Acsl4), a pivotal enzyme in the regulation of lipid biosynthesis, benefits the initiation of ferroptosis, but its role in gliomas needs further clarification. Erastin, a classic inducer of ferroptosis, has recently been found to regulate lipid peroxidation by regulating Acsl4 other than glutathione peroxidase 4 (GPX4) in ferroptosis. In this study, we demonstrated that heat shock protein 90 (Hsp90) and dynamin-related protein 1 (Drp1) actively regulated and stabilized Acsl4 expression in erastin-induced ferroptosis in gliomas. Hsp90 overexpression and calcineurin (CN)-mediated Drp1 dephosphorylation at serine 637 (Ser637) promoted ferroptosis by altering mitochondrial morphology and increasing Acsl4-mediated lipid peroxidation. Importantly, promotion of the Hsp90-Acsl4 pathway augmented anticancer activity of erastin in vitro and in vivo. Our discovery reveals a novel and efficient approach to ferroptosis-mediated glioma therapy.
Project description:LHPP, a novel, recognized tumor suppressor, exerts a critical influence on the regulation of tumor cell proliferation and survival by modulating various signaling pathways with its phosphatase activity. Here, we unveil a robust correlation between reduced LHPP expression and adverse prognosis in prostate cancer. We demonstrate that LHPP interacts with AKT, thereby dampening AKT phosphorylation and subsequently inhibiting ACSL4 phosphorylation at the T624 site. This interaction impedes phosphorylation-dependent ubiquitination, thwarting SKP2 from recognizing and binding to ACSL4 at the K621 site. As a result, ACSL4 is spared from lysosomal degradation, leading to its accumulation and the promotion of lipid peroxidation, and ferroptosis. Moreover, our findings reveal that Panobinostat, a potent histone-deacetylase inhibitor, intricately regulates LHPP expression at multiple levels through the inhibition of HDAC3. This complex modulation enhances the ferroptosis pathway, offering a novel mechanism for curtailing the growth of prostate tumors and highlighting its significant translational potential for clinical application.
Project description:Immune checkpoint blockade (ICB) is a promising treatment strategy for colorectal cancer (CRC) patients. However, most CRC patients do not response well to ICB therapy. Increasing evidence indicates that ferroptosis plays a critical role in immunotherapy. ICB efficacy may be enhanced by inducing tumor ferroptosis. Cytochrome P450 1B1 (CYP1B1) is a metabolic enzyme that participates in arachidonic acid metabolism. However, the role of CYP1B1 in ferroptosis remains unclear. In this study, we demonstrated that CYP1B1 derived 20-HETE activated the protein kinase C pathway to increase FBXO10 expression, which in turn promoted the ubiquitination and degradation of acyl-CoA synthetase long-chain family member 4 (ACSL4), ultimately inducing tumor cells resistance to ferroptosis. Furthermore, inhibiting CYP1B1 sensitized tumor cells to anti-PD-1 antibody in a mouce model. In addition, CYP1B1 expression was negatively correlated with ACSL4 expression, and high expression indicates poor prognosis in CRC. Taken together, our work identified CYP1B1 as a potential biomarker for enhancing anti-PD-1 therapy in CRC.
Project description:Ferroptosis is a recently identified form of regulated cell death that plays a crucial role in tumor suppression. In this study, we found that F2 (the gene encoding thrombin) was strongly upregulated in breast cancer (BRCA, TCGA Study Abbreviations) compared with normal samples and that lower F2 levels were associated with poorer prognosis in breast cancer patients. Thrombin induces ferroptosis in triple-negative breast cancer (TNBC) cells by activation of cytosolic phospholipase A2α (cPLA2α) activity to increase the release of arachidonic acid (AA). TNBC in all breast cancer subtypes exhibited the highest levels of PLA2G4A (the gene encoding cPLA2α) and Acsl4, and inhibition of cPLA2α and its downstream enzyme acyl-CoA synthetase long-chain family member 4 (ACSL4) reversed thrombin toxicity. In a mouse xenograft model of TNBC, thrombin treatment suppressed breast cancer growth which can be inhibited by ferroptosis inhibitor Liproxstatin-1 (Lip-1). Our study underscores the potential of the thrombin-ACSL4 axis as a promising therapeutic target for the treatment of TNBC.
Project description:BackgroundDiscovering an inhibitor for acyl-CoA synthetase long-chain family member 4 (ACSL4), a protein that triggers cell injury via ferroptosis, presents potential to minimize cellular damage. This study investigates paeonol (PAE), a traditional Chinese herbal medicine, as an ACSL4 inhibitor to prevent chondrocyte ferroptosis and protect against osteoarthritis (OA).MethodsWe conducted in vitro experiments using mouse chondrocytes treated with PAE to mitigate ferroptosis induced by Interleukin-1 Beta (IL-1β) or ferric ammonium citrate (FAC), examining intracellular ferroptotic indicators, cartilage catabolic markers, and ferroptosis regulatory proteins. A mouse OA model was created via destabilized medial meniscus (DMM), followed by intra-articular PAE injections. After 8 weeks, micro-computed tomography and histological assessments evaluated PAE's protective and anti-ferroptotic effects in the OA model.ResultsIn vitro results showed PAE significantly reduced IL-1β/FAC-induced damage by targeting ACSL4, including cell apoptosis, inflammatory responses, extracellular matrix degradation, and ferroptotic markers (oxidative stress, lipid peroxidation, and iron buildup). It also restored the expression of ferroptotic suppressors and mitigated mitochondrial damage. Additionally, PAE increased cartilage anabolic marker expression while reducing cartilage catabolic marker expression. Molecular docking, cellular thermal shift assay, and drug affinity responsive target stability analysis verified the binding interaction between PAE and ACSL4. Furthermore, the role of PAE in chondrocytes was further verified through ACSL4 knockdown and overexpression. In vivo, mice with OA showed increased cartilage degradation and ferroptosis, while intra-articular PAE injection alleviated these pathological changes.ConclusionPAE significantly protects chondrocytes from ferroptosis induced by IL-1β/FAC in primary mouse chondrocytes and DMM surgery-induced OA mice through ACSL4 inhibition.The translational potential of this articleThese findings highlight the potential of targeting ACSL4 in chondrocytes as a treatment strategy for OA, positioning PAE as a promising drug candidate.
Project description:Clear cell renal cell carcinoma (ccRCC) is a common genitourinary malignancy characterized by dysregulated cellular metabolism leading to aberrant glucose metabolism, fatty acid accumulation, and excessive reactive oxygen species production. ccRCC cells exhibit an augmented oxidative stress response. Complex interactions between iron metabolism and lipid homeostasis in ccRCC cells require a counteracting response that enables ferroptosis evasion and survival maintenance. Additionally, abnormal GA-binding protein transcription factor subunit alpha (GABPA) expression is associated with ccRCC occurrence and development, but its impact on ferroptosis-related molecular mechanisms remains unclear. Herein, we examined the impact of the GABPA-ACSL4 pathway on ferroptosis in ccRCC through bioinformatics analysis, as well as in vitro and in vivo experiments. In contrast to that in adjacent normal tissues, GABPA expression was significantly downregulated in ccRCC tissues, and this downregulation was linked to poor overall survival. Increased GABPA expression suppressed ccRCC cell proliferation, migration, and invasion. Moreover, GABPA overexpression increased the susceptibility of ccRCC cells to ferroptosis. Additionally, GABPA directly bound to the promoter region of ACSL4, promoting ferroptosis. Thus, inducing the GABPA-ACSL4 pathway activates ferroptosis, inhibits proliferation or metastasis, and exerts anticancer activity in ccRCC. These findings have important implications for regulating ccRCC occurrence and development.
Project description:Ferroptosis is a novel type of programmed cell death that differs from apoptosis in that it involves iron-dependent peroxidation of membrane phospholipids. Its role in a variety of human disorders, including cancer has been hypothesized in recent years. While it may function as an endogenous tumor suppressor in a variety of cancers, its role during initiation and progression of liver cancer, particularly hepatocellular carcinoma (HCC), is yet unknown. Because HCC is most commonly found in chronically injured livers, we utilized two well-established mouse models of chronic injury-dependent HCC formation: Treatment with streptozotocin and high-fat diet as metabolic injury model, as well as treatment with diethylnitrosamine and carbon tetrachloride as toxic injury model. We used mice with hepatocyte-specific deletion of Acsl4, a key mediator of ferroptosis, to explore the significance of ferroptotic cell death in hepatocytes, the cell type of origin for HCC. Surprisingly, preventing ferroptotic cell death in hepatocytes by deleting Acsl4 does not increase the formation of HCC. Furthermore, Acsl4-deficient livers display less fibrosis and proliferation, especially in the HCC model of toxic damage. Intriguingly, in this model, the absence of ACSL4-dependent processes such as ferroptosis significantly slow down the growth of HCC. These findings suggest that during HCC formation in a chronically injured liver, ferroptotic cell death is not an endogenous tumor-suppressive mechanism. Instead, we find that ACSL4-dependent processes have an unanticipated cancer-promoting effect during HCC formation, which is most likely due to aggravated liver damage as demonstrated by increased hepatic fibrosis. Previous studies suggested that ferroptosis might have beneficial effects for patients during HCC therapy. As a result, during HCC progression and therapy, ferroptosis may have both cancer-promoting and cancer-inhibitory effects, respectively.
Project description:Cyclin-dependent kinase 4 and 6 inhibitors (CDK4/6 inhibitors) can significantly extend tumor response in patients with metastatic luminal A breast cancer, yet intrinsic and acquired resistance remains a prevalent issue. Understanding the molecular features of CDK4/6 inhibitor sensitivity and the potential efficacy of their combination with novel targeted cell death inducers may lead to improved patient outcomes. Herein, we demonstrate that ferroptosis, a form of regulated cell death driven by iron-dependent phospholipid peroxidation, partly underpins the efficacy of CDK4/6 inhibitors. Mechanistically, CDK4/6 inhibitors downregulate the cystine transporter SLC7A11 by inhibiting SP1 binding to the SLC7A11 promoter region. Furthermore, SLC7A11 is identified as critical for the intrinsic sensitivity of luminal A breast cancer to CDK4/6 inhibitors. Both genetic and pharmacological inhibition of SP1 or SLC7A11 enhances cell sensitivity to CDK4/6 inhibitors and synergistically inhibits luminal A breast cancer growth when combined with CDK4/6 inhibitors in vitro and in vivo. Our data highlight the potential of targeting SLC7A11 in combination with CDK4/6 inhibitors, supporting further investigation of combination therapy in luminal A breast cancer.
Project description:BackgroundRecent evidence shows that inducing ferroptosis may improve efficacy of tumor therapy. However, ferroptosis-related genes have been little studied in patients with breast cancer especially in the neoadjuvant setting. ACSL4 and GPX4 have been well established as the positive and negative regulator of ferroptosis, respectively. This study aimed to explore the predictive value of ACSL4 and GPX4 for patients with breast cancer administered neoadjuvant chemotherapy.MethodsThis study included patients treated with paclitaxel-cisplatin-based neoadjuvant chemotherapy. Immunohistochemistry staining of ACSL4 and GPX4 was carried out on the core needle biopsy specimens. Logistic regression was performed to explore the predictive biomarkers of pathological complete response (pCR). Survival analyses were examined by log-rank test and Cox proportional hazard regression.FindingsA total of 199 patients were included for the analyses. Both ACSL4 expression and ACSL4/GPX4 combination status could serve as independent predictive factors for pCR. The interaction for pCR was observed between ACSL4 and clinical tumor stage. Besides, ACSL4 expression, GPX4 expression, and their combination status were independent prognostic factors for disease-free survival. Analyses of the Kaplan-Meier Plotter database suggested that higher ACSL4 expression is related to better overall survival, and higher GPX4 expression is related to better distant metastasis-free survival. Pathway analyses revealed that ACSL4 and GPX4 might function in crucial pathways including apoptosis, autophagy, cell adhesion, lipid metabolism, etc. INTERPRETATION: This study revealed the critical value of ACSL4 and GPX4 serving as novel predictive and prognostic biomarkers for patients with breast cancer receiving neoadjuvant chemotherapy. It might be a novel strategy to induce ferroptosis to promote chemosensitivity. Future studies are required to elucidate the potential mechanisms.FundingThis work was supported by Shanghai Natural Science Foundation [grant number 19ZR1431100], Clinical Research Plan of Shanghai Hospital Development Center [grant numbers SHDC2020CR3003A, 16CR3065B, and 12016231], Shanghai "Rising Stars of Medical Talent" Youth Development Program for Youth Medical Talents - Specialist Program [grant number 2018-15], Shanghai "Rising Stars of Medical Talent" Youth Development Program for Outstanding Youth Medical Talents [grant number 2018-16], Shanghai Collaborative Innovation Center for Translational Medicine [grant number TM201908], Multidisciplinary Cross Research Foundation of Shanghai Jiao Tong University [grant numbers YG2017QN49, ZH2018QNA42, and YG2019QNA28], Nurturing Fund of Renji Hospital [grant numbers PYMDT-002, PY2018-IIC-01, PY2018-III-15, and PYIII20-09], Science and Technology Commission of Shanghai Municipality [grant numbers 20DZ2201600 and 15JC1402700], and Shanghai Municipal Key Clinical Specialty.