The E3 Ubiquitin Ligase NEDD4-1 Mediates Temozolomide-Resistant Glioblastoma through PTEN Attenuation and Redox Imbalance in Nrf2-HO-1 Axis

• Published in: International journal of molecular sciences Vol. 22; no. 19; p. 10247
• Main Authors: Chuang, Hao-Yu, Hsu, Li-Yun, Pan, Chih-Ming, Pikatan, Narpati Wesa, Yadav, Vijesh Kumar, Fong, Iat-Hang, Chen, Chao-Hsuan, Yeh, Chi-Tai, Chiu, Shao-Chih
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI AG 23-09-2021; MDPI
• Subjects: 1-Phosphatidylinositol 3-kinase; Aged; AKT protein; Animals; Antioxidants; Apoptosis; Biological effects; Brain cancer; Brain Neoplasms - metabolism; Brain tumors; Cell Line, Tumor; Chemoresistance; Chemotherapy; Down-Regulation - drug effects; Drug Resistance, Neoplasm - drug effects; Embryogenesis; Female; Gene expression; Gene Expression Regulation, Neoplastic - drug effects; Glioblastoma; Glioblastoma - drug therapy; Glioblastoma - metabolism; Heme Oxygenase-1 - metabolism; Homology; Humans; Immunohistochemistry; Indole-3-carbinol; Male; Medical prognosis; Metastasis; Mice; Mice, Inbred NOD; Mice, SCID; MicroRNAs; MicroRNAs - metabolism; miRNA; mRNA; Nedd4 Ubiquitin Protein Ligases - metabolism; NEDD4-1; NF-E2-Related Factor 2 - metabolism; Oxidation-Reduction - drug effects; Oxidative stress; Patients; Polymerase chain reaction; Proteins; PTEN Phosphohydrolase - metabolism; PTEN protein; Reactive Oxygen Species - metabolism; Signal transduction; Signal Transduction - drug effects; Synergistic effect; Temozolomide; Temozolomide - therapeutic use; Tensin; TMZ resistance; TOR protein; Tumor cells; Tumor suppressor genes; Tumorigenesis; Tumorigenicity; Tumors; ubiquitin ligase; Ubiquitin-protein ligase; Ubiquitin-Protein Ligases - metabolism; Up-Regulation - drug effects; ubiquitin ligase; TMZ resistance; NEDD4-1; glioblastoma; indole-3-carbinol
• ISSN: 1422-0067; 1661-6596; 1422-0067
• DOI: 10.3390/ijms221910247

Glioblastoma (GBM) is the most common primary malignant brain tumor in adults. It is highly resistant to chemotherapy, and tumor recurrence is common. Neuronal precursor cell-expressed developmentally downregulated 4-1 (NEDD4-1) is an E3 ligase that controls embryonic development and animal growth. NEDD4-1 regulates the tumor suppressor phosphatase and tensin homolog (PTEN), one of the major regulators of the PI3K/AKT/mTOR signaling axis, as well as the response to oxidative stress.
The expression levels of NEDD4-1 in GBM tissues and different cell lines were determined by quantitative real-time polymerase chain reaction and immunohistochemistry. In vitro and in vivo assays were performed to explore the biological effects of NEDD4-1 on GBM cells. Temozolomide (TMZ)-resistant U87MG and U251 cell lines were specifically established to determine NEDD4-1 upregulation and its effects on the tumorigenicity of GBM cells. Subsequently, miRNA expression in TMZ-resistant cell lines was investigated to determine the dysregulated miRNA underlying the overexpression of NEDD4-1. Indole-3-carbinol (I3C) was used to inhibit NEDD4-1 activity, and its effect on chemoresistance to TMZ was verified.
NEDD4-1 was significantly overexpressed in the GBM and TMZ-resistant cells and clinical samples. NEDD4-1 was demonstrated to be a key oncoprotein associated with TMZ resistance, inducing oncogenicity and tumorigenesis of TMZ-resistant GBM cells compared with TMZ-responsive cells. Mechanistically, TMZ-resistant cells exhibited dysregulated expression of miR-3129-5p and miR-199b-3p, resulting in the induced NEDD4-1 mRNA-expression level. The upregulation of NEDD4-1 attenuated PTEN expression and promoted the AKT/NRF2/HO-1 oxidative stress signaling axis, which in turn conferred amplified defense against reactive oxygen species (ROS) and eventually higher resistance against TMZ treatment. The combination treatment of I3C, a known inhibitor of NEDD4-1, with TMZ resulted in a synergistic effect and re-sensitized TMZ-resistant tumor cells both in vitro and in vivo.
These findings demonstrate the critical role of NEDD4-1 in regulating the redox imbalance in TMZ-resistant GBM cells via the degradation of PTEN and the upregulation of the AKT/NRF2/HO-1 signaling pathway. Targeting this regulatory axis may help eliminate TMZ-resistant glioblastoma.