RESUMO
Background: Triple-negative breast cancer (TNBC) is a subtype of BC with high rates of mortality. The mechanism of PTPRG-AS1 in ferroptosis of TNBC was investigated. Methods: Chromatin immunoprecipitation and dual-luciferase reporter assays were used to measure intermolecular relationships. MTT and colony formation assays detected cell viability and proliferation. Kits detected Fe2+ and reactive oxygen species levels. The role of PTPRG-AS1 in tumor growth was analyzed in vivo. Results: PTPRG-AS1 was increased in TNBC tissues and cells. PTPRG-AS1 silencing increased the reduction of glutathione and GPX4, increased Fe2+ and reactive oxygen species in erastin-treated cells and inhibited proliferation. POU2F2 transcriptionally upregulated PTPRG-AS1. PTPRG-AS1 targeted miR-376c-3p to upregulate SLC7A11. PTPRG-AS1 knockdown suppressed tumor growth in vivo. Conclusion: POU2F2 transcriptionally activates PTPRG-AS1 to modulate ferroptosis and proliferation by miR-376c-3p/SLC7A11, promoting TNBC.
Triple-negative breast cancer (TNBC) is a kind of breast cancer with high recurrence and low survival rates. Activation of the ferroptosis pathway can inhibit BC proliferation and distant metastasis. Therefore, identifying effective biomarkers and molecular mechanisms of ferroptosis in TNBC is important for its earlier detection and therapy. PTPRG-AS1 is a new type of lncRNA discovered in recent years that is increased in various diseases and is related to prognosis. In the present study, the authors found that POU2F2 promoted PTPRG-AS1 transcription. PTPRG-AS1 knockdown activated ferroptosis in TNBC and inhibited proliferation. Mechanistically, PTPRG-AS1 targeted miR-376c-3p to upregulate SLC7A11, thereby inhibiting ferroptosis and promoting TNBC development. These results indicate that PTPRG-AS1 is a possible therapeutic target in TNBC.
Assuntos
Ferroptose , MicroRNAs , Fator 2 de Transcrição de Octâmero , RNA Longo não Codificante , Neoplasias de Mama Triplo Negativas , Humanos , Sistema y+ de Transporte de Aminoácidos/genética , Linhagem Celular Tumoral , Proliferação de Células/genética , Ferroptose/genética , Regulação Neoplásica da Expressão Gênica , MicroRNAs/genética , Fator 2 de Transcrição de Octâmero/genética , Espécies Reativas de Oxigênio , Proteínas Tirosina Fosfatases Classe 5 Semelhantes a Receptores/genética , RNA Longo não Codificante/genética , Neoplasias de Mama Triplo Negativas/genética , Neoplasias de Mama Triplo Negativas/patologia , Regulação para CimaRESUMO
Purpose: To determine the role of UCH-L1 in regulating ERα expression, and to evaluate whether therapeutic targeting of UCH-L1 can enhance the efficacy of anti-estrogen therapy against breast cancer with loss or reduction of ERα. Methods: Expressions of UCH-L1 and ERα were examined in breast cancer cells and patient specimens. The associations between UCH-L1 and ERα, therapeutic response and prognosis in breast cancer patients were analyzed using multiple databases. The molecular pathways by which UCH-L1 regulates ERα were analyzed using immunoblotting, qRT-PCR, immunoprecipitation, ubiquitination, luciferase and ChIP assays. The effects of UCH-L1 inhibition on the efficacy of tamoxifen in ERα (-) breast cancer cells were tested both in vivo and in vitro. Results: UCH-L1 expression was conversely correlated with ERα status in breast cancer, and the negative regulatory effect of UCH-L1 on ERα was mediated by the deubiquitinase-mediated stability of EGFR, which suppresses ERα transcription. High expression of UCH-L1 was associated with poor therapeutic response and prognosis in patients with breast cancer. Up-regulation of ERα caused by UCH-L1 inhibition could significantly enhance the efficacy of tamoxifen and fulvestrant in ERα (-) breast cancer both in vivo and in vitro. Conclusions: Our results reveal an important role of UCH-L1 in modulating ERα status and demonstrate the involvement of UCH-L1-EGFR signaling pathway, suggesting that UCH-L1 may serve as a novel adjuvant target for treatment of hormone therapy-insensitive breast cancers. Targeting UCH-L1 to sensitize ER negative breast cancer to anti-estrogen therapy might represent a new therapeutic strategy that warrants further exploration.
