Search

Background: Ferroptosis plays a key role in human cancer, but its function and mechanism in glioma is not clear. P62/SQSTM1 was reported to inhibit ferroptosis via the activation of NRF2 signaling pathway. In this study we reveal a dual role of p62 in ferroptosis of glioblastoma (GBM) according to p53 status. Method: Lipid peroxidation analysis, transmission electron microscopy (TEM), GSH assay were performed to determine the level of ferroptosis. Western blot and qPCR were obtained to detect the expression of ferroptosis markers. Construction of mutant plasmids, immunoprecipitation, luciferase assay and rescue-experiments were performed to explore the regulatory mechanism. Results: P62 overexpression facilitates ferroptosis and inhibits SLC7A11 expression in p53 mutant GBM, while attenuates ferroptosis and promotes SLC7A11 expression in p53 wild-type GBM. P62 associates with p53 and inhibits its ubiquitination. The p53-NRF2 association and p53-mediated suppression of NRF2 antioxidant activity are diversely regulated by p62 according to p53 status. P53 mutation status is required for the dual regulation of p62 on ferroptosis. In wild-type p53 GBM, the classical p62-mediated NRF2 activation pathway plays a major regulatory role of ferroptosis, leading to increased SLC7A11 expression, resulting in a anti-ferroptosis role. In mutant p53 GBM, stronger interaction of mutant-p53/NRF2 by p62 enhance the inhibitory effect of mutant p53 on NRF2 signaling, which reversing the classical p62-mediated NRF2 activation pathway, together with increased p53's transcriptional suppression on SLC7A11 by p62, leading to a decrease of SLC7A11, resulting in a pro-ferroptosis role. Conclusion: Together, this study shows novel molecular mechanisms of ferroptosis regulated by p62; the mutation status of p53 is an important factor that determines the therapeutic response to p62-mediated ferroptosis-targeted therapies in GBM. [ABSTRACT FROM AUTHOR]

Background: Ferroptosis is an iron dependent cell death closely associated with p53 signaling pathway and is aberrantly regulated in glioblastoma (GBM), yet the underlying mechanism needs more exploration. Identifying new factors which regulate p53 and ferroptosis in GBM is essential for treatment. Methods: Glioma cell growth was evaluated by cell viability assays and colony formation assays. Lipid reactive oxygen species (ROS) assays, lipid peroxidation assays, glutathione assays, and transmission electron microscopy were used to assess the degree of cellular lipid peroxidation of GBM. The mechanisms of RND1 in regulation of p53 signaling were analyzed by RT-PCR, western blot, immunostaining, co-immunoprecipitation, ubiquitination assays and luciferase reporter assays. The GBM‐xenografted animal model was constructed and the tumor was captured by an In Vivo Imaging System (IVIS). Results: From the The Cancer Genome Atlas (TCGA) database, we summarized that Rho family GTPase 1 (RND1) expression was downregulated in GBM and predicted a better prognosis of patients with GBM. We observed that RND1 influenced the glioma cell growth in a ferroptosis-dependent manner when GBM cell lines U87 and A172 were treated with Ferrostatin-1 or Erastin. Mechanistically, we found that RND1 interacted with p53 and led to the de-ubiquitination of p53 protein. Furthermore, the overexpression of RND1 promoted the activity of p53-SLC7A11 signaling pathway, therefore inducing the lipid peroxidation and ferroptosis of GBM. Conclusions: We found that RND1, a novel controller of p53 protein and a positive regulator of p53 signaling pathway, enhanced the ferroptosis in GBM. This study may shed light on the understanding of ferroptosis in GBM cells and provide new therapeutic ideas for GBM. [ABSTRACT FROM AUTHOR]

Background: Ferroptosis plays a key role in human cancer, but its function and mechanism in glioma is not clear. P62/SQSTM1 was reported to inhibit ferroptosis via the activation of NRF2 signaling pathway. In this study we reveal a dual role of p62 in ferroptosis of glioblastoma (GBM) according to p53 status. Method: Lipid peroxidation analysis, transmission electron microscopy (TEM), GSH assay were performed to determine the level of ferroptosis. Western blot and qPCR were obtained to detect the expression of ferroptosis markers. Construction of mutant plasmids, immunoprecipitation, luciferase assay and rescue-experiments were performed to explore the regulatory mechanism. Results: P62 overexpression facilitates ferroptosis and inhibits SLC7A11 expression in p53 mutant GBM, while attenuates ferroptosis and promotes SLC7A11 expression in p53 wild-type GBM. P62 associates with p53 and inhibits its ubiquitination. The p53-NRF2 association and p53-mediated suppression of NRF2 antioxidant activity are diversely regulated by p62 according to p53 status. P53 mutation status is required for the dual regulation of p62 on ferroptosis. In wild-type p53 GBM, the classical p62-mediated NRF2 activation pathway plays a major regulatory role of ferroptosis, leading to increased SLC7A11 expression, resulting in a anti-ferroptosis role. In mutant p53 GBM, stronger interaction of mutant-p53/NRF2 by p62 enhance the inhibitory effect of mutant p53 on NRF2 signaling, which reversing the classical p62-mediated NRF2 activation pathway, together with increased p53's transcriptional suppression on SLC7A11 by p62, leading to a decrease of SLC7A11, resulting in a pro-ferroptosis role. Conclusion: Together, this study shows novel molecular mechanisms of ferroptosis regulated by p62; the mutation status of p53 is an important factor that determines the therapeutic response to p62-mediated ferroptosis-targeted therapies in GBM. [ABSTRACT FROM AUTHOR]