ATOH8 confers the vulnerability of tumor cells to ferroptosis by repressing SCD expression [ChIP-Seq]
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ABSTRACT: Ferroptosis, a non-apoptotic programmed cell death triggered by excessive iron-dependent lipid peroxidation, plays a pivotal role in tumor progression. Significant progress has been made in elucidating the role of transcription factors in the regulation of ferroptosis. Nevertheless, the identification of the key transcription factor responsible for inducing ferroptosis remains elusive. In this study, we discovered that ATOH8 is upregulated in prostate cancer cells treated with the ferroptosis inducer. Overexpression of ATOH8 increased the vulnerability of prostate cancer to ferroptosis, while ATOH8 deletion promotes ferroptosis evasion. Mechanistically, ATOH8 suppresses the transcription of SCD, reducing the synthesis of monounsaturated fatty acids that confer resistance to ferroptosis. Additionally, ATOH8 works in conjunction with the E protein E47 to form a transcriptional repression complex that inhibits SCD transcription. Furthermore, we discovered that EZH2 epigenetically suppresses the expression of ATOH8 through DNA methylation and H3K27 methylation. Interestingly, EZH2 was found to be downregulated in ferroptosis, resulting in an upregulation of ATOH8. Pharmacological inhibition of EZH2 combined with ferroptosis inducer significantly suppresses prostate cancer growth in vitro and in vivo. Together, our findings unveil that EZH2-mediated ATOH8 downregulation promotes ferroptosis evasion and suggest that pharmacological manipulation of EZH2 and ATOH8 is a promising therapeutic strategy for prostate cancer.
Project description:Ferroptosis, a non-apoptotic programmed cell death triggered by excessive iron-dependent lipid peroxidation, plays a pivotal role in tumor progression. Significant progress has been made in elucidating the role of transcription factors in the regulation of ferroptosis. Nevertheless, the identification of the key transcription factor responsible for inducing ferroptosis remains elusive. In this study, we discovered that ATOH8 is upregulated in prostate cancer cells treated with the ferroptosis inducer. Overexpression of ATOH8 increased the vulnerability of prostate cancer to ferroptosis, while ATOH8 deletion promotes ferroptosis evasion. Mechanistically, ATOH8 suppresses the transcription of SCD, reducing the synthesis of monounsaturated fatty acids that confer resistance to ferroptosis. Additionally, ATOH8 works in conjunction with the E protein E47 to form a transcriptional repression complex that inhibits SCD transcription. Furthermore, we discovered that EZH2 epigenetically suppresses the expression of ATOH8 through DNA methylation and H3K27 methylation. Interestingly, EZH2 was found to be downregulated in ferroptosis, resulting in an upregulation of ATOH8. Pharmacological inhibition of EZH2 combined with ferroptosis inducer significantly suppresses prostate cancer growth in vitro and in vivo. Together, our findings unveil that EZH2-mediated ATOH8 downregulation promotes ferroptosis evasion and suggest that pharmacological manipulation of EZH2 and ATOH8 is a promising therapeutic strategy for prostate cancer.
Project description:Palbociclib is a CDK4/6 inhibitor approved for the treatment of breast cancer by suppressing cell proliferation. However, monotherapy with palbociclib was discouraging in prostate cancer, calling for a mechanism-based effective therapy. In this study, we reported in prostate cancer that palbociclib is a potent sensitizer of ferroptosis, which is worked out by downregulating the expression of TRIB3, a gene highly expressed in prostate cancer. Specifically, TRIB3 knockdown augmented the response of prostate cancer cells to ferroptosis inducers, whereas, TRIB3 overexpression rescued prostate cancer cells from palbociclib-induced ferroptosis. Mechanistically, TRIB3 inhibition by palbociclib resulted in downregulation of SOX2, which subsequently led to compromised expression of SLC7A11, a cystine/glutamate antiporter that counteracts ferroptosis. Functionally, a combined treatment of palbociclib with ferroptosis inducer significantly suppressed prostate cancer growth in a xenograft tumor model. Together, these results uncover an essential role of TRIB3/SOX2/SLC7A11 axis in palbociclib-induced ferroptosis, suggesting palbociclib a promising targeted therapy in combine with ferroptosis induction for the treatment of prostate cancer.
Project description:Ferroptosis suppresses tumor growth. Finding out potent pro-ferroptosis regulators via new approaches is extremely helpful for guiding and improving ferroptosis-based anti-tumor therapy. To seek pro-ferroptosis regulators, we proposed a novel screening strategy which focuses on molecules consistently upregulated even after long-time treatment of ferroptosis inducer. RNA-seq of RSL3-treated cells was performed as to be analysed together with RNA-seq data of ferroptosis-resistant cells in GEO dataset. Cysteine-rich angiogenic inducer 61 (CYR61) was identified as a novel pro-ferroptosis regulator via our new mining strategy.
Project description:The ability of cancer cells to switch phenotype in response to a dynamic intra-tumor microenvironment is a major barrier to effective therapy. In melanoma, down-regulation of the lineage addiction oncogene MITF (Microphthalmia-associated transcription factor) is a hallmark of the proliferative-to-invasive phenotype switch. Yet how MITF promotes proliferation and suppresses invasion is poorly understood. Here we show that expression of the key lipogenic enzyme stearoyl-CoA desaturase (SCD) is activated by MITF, but suppressed by the stress-responsive transcription factor ATF4. SCD expression is required for MITF-positive melanoma cell proliferation,. By contrast, MITF-low cells express reduced levels of SCD and are insensitive to its inhibition, indicating that cell phenotype dictates response to drugs targeting lipid metabolism. Since SCD suppresses inflammatory signalling and ATF4 expression, the results identify a positive feedback-loop that can maintain an invasive phenotype, uncover a key role for MITF and ATF4 in metabolic reprograming, and reveal fatty acid composition as a driver of melanoma phenotype-switching.
Project description:Background: Mucosal melanoma (MM) is epidemiologically, biologically, and molecularly distinct from cutaneous melanoma. Current treatment strategies have failed to significantly improve the prognosis for MM patients. This study aims to identify therapeutic targets and develop combination strategies by investigating the mechanisms underlying the tumorigenesis and progression of MM. Methods: We analyzed the copy number amplification of EZH2 in 547 melanoma patients and investigated its correlation with clinical prognosis. Utilizing cell lines, organoids, and patient-derived xenograft models, we assessed the impact of EZH2 on cell proliferation and sensitivity to ferroptosis. Further, we explored the mechanisms of ferroptosis resistance associated with EZH2 by conducting RNA sequencing and chromatin immunoprecipitation sequencing. Results: EZH2 copy number amplification was closely associated with malignant phenotype and poor prognosis in MM patients. EZH2 was essential for MM cell proliferation in vitro and in vivo. Moreover, genetic perturbation of EZH2 rendered MM cells sensitized to ferroptosis. Combination treatment of EZH2 inhibitor with ferroptosis inducer significantly inhibited the growth of MM. Mechanistically, EZH2 inhibited the expression of KLF14, which binds to the promoter of SLC7A11 to repress its transcription. Loss of EZH2 therefore reduced the expression of SLC7A11, leading to reduced intracellular SLC7A11-dependent glutathione synthesis to promote ferroptosis. Conclusion: Our findings not only establish EZH2 as a biomarker for MM prognosis, but also highlight the EZH2-KLF14-SLC7A11 axis as a potential target for MM treatment.
Project description:Background: Mucosal melanoma (MM) is epidemiologically, biologically, and molecularly distinct from cutaneous melanoma. Current treatment strategies have failed to significantly improve the prognosis for MM patients. This study aims to identify therapeutic targets and develop combination strategies by investigating the mechanisms underlying the tumorigenesis and progression of MM. Methods: We analyzed the copy number amplification of EZH2 in 547 melanoma patients and investigated its correlation with clinical prognosis. Utilizing cell lines, organoids, and patient-derived xenograft models, we assessed the impact of EZH2 on cell proliferation and sensitivity to ferroptosis. Further, we explored the mechanisms of ferroptosis resistance associated with EZH2 by conducting RNA sequencing and chromatin immunoprecipitation sequencing. Results: EZH2 copy number amplification was closely associated with malignant phenotype and poor prognosis in MM patients. EZH2 was essential for MM cell proliferation in vitro and in vivo. Moreover, genetic perturbation of EZH2 rendered MM cells sensitized to ferroptosis. Combination treatment of EZH2 inhibitor with ferroptosis inducer significantly inhibited the growth of MM. Mechanistically, EZH2 inhibited the expression of KLF14, which binds to the promoter of SLC7A11 to repress its transcription. Loss of EZH2 therefore reduced the expression of SLC7A11, leading to reduced intracellular SLC7A11-dependent glutathione synthesis to promote ferroptosis. Conclusion: Our findings not only establish EZH2 as a biomarker for MM prognosis, but also highlight the EZH2-KLF14-SLC7A11 axis as a potential target for MM treatment.
Project description:Androgen receptor signaling inhibitors (ARSIs) have demonstrated a survival benefit in metastatic prostate cancer (PCa). However, patients taking these agents inevitably acquire resistance and even develop neuroendocrine prostate cancer (NEPC), in which stage, the AR signaling is inactive, and therapies are limited for these lethal cases. Therefore, there is an urgent need to develop novel treatments to improve patient outcomes. Here we report that L14-8, a small molecule derived and optimized from ezetimibe, significantly suppressed prostate cancer growth by inducing ferroptosis in vitro and in vivo without obvious toxicity. Further mechanism studies demonstrate that L14-8 bound to and enhanced the stability of PLK1 and promoted the phosphorylation and expression of TP53, which enhanced its enrichment at the promoter of SAT1, a ferroptosis inducer, and increased its transcriptional activity. Overall, our studies developed a novel anti-tumor agent for treating lethal prostate cancer in an AR-independent manner and provided mechanistic insights into its action by targeting the PLK1-mediated TP53-SAT1 axis-induced ferroptosis.
Project description:SCD had hemolysis with elevated levels of heme and iron, which induced ferroptosis. Here, we found Nrf2 knockout in SCD mice accumulated the levels of the metabolite L-2-hydroxyglutarate (L2HG), which impaired ferroptosis stress response to exacerbate SCD symptom. Mechanistically, L2HG was found to regulate the expression of genes involved in the iron and heme metabolism via histone epigenetic hypermethylation. Our findings indicate an important role of Nrf2/L2HG in SCD for ferroptosis response.
Project description:SCD had hemolysis with elevated levels of heme and iron, which induced ferroptosis. Here, we found Nrf2 knockout in SCD mice accumulated the levels of the metabolite L-2-hydroxyglutarate (L2HG), which impaired ferroptosis stress response to exacerbate SCD symptom. Mechanistically, L2HG was found to regulate the expression of genes involved in the iron and heme metabolism via histone epigenetic hypermethylation. Our findings indicate an important role of Nrf2/L2HG in SCD for ferroptosis response.
Project description:SCD had hemolysis with elevated levels of heme and iron, which induced ferroptosis. Here, we found Nrf2 knockout in SCD mice accumulated the levels of the metabolite L-2-hydroxyglutarate (L2HG), which impaired ferroptosis stress response to exacerbate SCD symptom. Mechanistically, L2HG was found to regulate the expression of genes involved in the iron and heme metabolism via histone epigenetic hypermethylation. Our findings indicate an important role of Nrf2/L2HG in SCD for ferroptosis response.