title: The CHAC1-inhibited Notch3 pathway is involved in temozolomide-induced glioma cytotoxicity.
abstract: Glioblastoma multiforme (GBM) is the high-grade primary glioma in adults. Temozolomide (TMZ), an alkylating agent of the imidazotetrazine series, is a first-line chemotherapeutic drug for clinical therapy. However, the expense of TMZ therapy and increasing drug resistance to TMZ decreases its therapeutic effects. Therefore, our aim was to investigate the detailed molecular mechanisms of TMZ-mediated cytotoxicity to enhance the efficacy of TMZ in clinical GBM therapy. First, TMZ-mediated gene expression profiles and networks in U87-MG cells were identified by transcriptome microarray and bioinformatic analyses. Cation transport regulator-like protein 1 (CHAC1) was the most highly TMZ-upregulated gene. Overexpression and knockdown of CHAC1 expression significantly influenced TMZ-mediated cell viability, apoptosis, caspase-3 activation, and poly(ADP ribose) polymerase (PARP) degradation. The c-Jun N-terminal kinase (JNK)1/c-JUN pathway was identified to participate in TMZ-upregulated CHAC1 expression via transcriptional control. Furthermore, CHAC1 levels were significantly decreased in GBM cell lines, TCGA array data, and tumor tissues. Overexpression of CHAC1 enhanced glioma apoptotic death via caspase-3/9 activation, PARP degradation, autophagy formation, reactive oxygen species generation, increased intracellular calcium, and loss of the mitochondria membrane potential. Finally, we also identified that TMZ significantly reduced Notch3 levels, which are upregulated in gliomas. TMZ also induced CHAC1 to bind to the Notch3 protein and inhibit Notch3 activation, resulting in attenuation of Notch3-mediated downstream signaling pathways. These results emphasize that CHAC1-inhibited Notch3 signaling can influence TMZ-mediated cytotoxicity. Our findings may provide novel therapeutic strategies for future glioblastoma therapy.
authors.affiliation: Graduate Institute of Medical Sciences, College of Medicine, Taipei Medical University, Taipei, Taiwan.
authors.forename: Peng-Hsu
authors.initials: PH
authors.lastname: Chen
authors.affiliation: Department of Pathology, Chi Mei Medical Center, Liouying, Tainan, Taiwan.
authors.forename: Wan-Lin
authors.initials: WL
authors.lastname: Shen
authors.affiliation: Graduate Institute of Medical Sciences, College of Medicine, Taipei Medical University, Taipei, Taiwan; Department of Biochemistry and Molecular Cell Biology, School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan.
authors.forename: Chwen-Ming
authors.initials: CM
authors.lastname: Shih
authors.affiliation: Department of Clinical Pharmacy, School of Pharmacy, Taipei Medical University, Taipei, Taiwan.
authors.forename: Kuo-Hao
authors.initials: KH
authors.lastname: Ho
authors.affiliation: Graduate Institute of Medical Sciences, College of Medicine, Taipei Medical University, Taipei, Taiwan; Department of Biochemistry and Molecular Cell Biology, School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan.
authors.forename: Chia-Hsiung
authors.initials: CH
authors.lastname: Cheng
authors.affiliation: Graduate Institute of Medical Sciences, College of Medicine, Taipei Medical University, Taipei, Taiwan; Department of Biochemistry and Molecular Cell Biology, School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan.
authors.forename: Cheng-Wei
authors.initials: CW
authors.lastname: Lin
authors.affiliation: Department of Pathology and Laboratory Medicine, Shin Kong Wu Ho-Su Memorial Hospital, Taipei, Taiwan.
authors.forename: Chin-Cheng
authors.initials: CC
authors.lastname: Lee
authors.affiliation: Department of Neurosurgery, Taipei City Hospital Ren-Ai Branch, Taipei, Taiwan.
authors.forename: Ann-Jeng
authors.initials: AJ
authors.lastname: Liu
authors.affiliation: Graduate Institute of Medical Sciences, College of Medicine, Taipei Medical University, Taipei, Taiwan; Department of Biochemistry and Molecular Cell Biology, School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan. Electronic address: kuchung@tmu.edu.tw.
authors.forename: Ku-Chung
authors.initials: KC
authors.lastname: Chen
mesh_terms: D018906:Antineoplastic Agents, Alkylating / Q000494:pharmacology* / Q000633:toxicity; D001343:Autophagy / Q000187:drug effects / Q000502:physiology; D002118:Calcium / Q000378:metabolism; D053148:Caspase 3 / Q000378:metabolism; D053453:Caspase 9 / Q000378:metabolism; D045744:Cell Line, Tumor; D002470:Cell Survival / Q000187:drug effects / Q000502:physiology; D003606:Dacarbazine / Q000031:analogs & derivatives* / Q000494:pharmacology / Q000633:toxicity; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects; D005910:Glioma / Q000188:drug therapy* / Q000378:metabolism / Q000473:pathology; D006801:Humans; D042541:Intracellular Space / Q000187:drug effects / Q000378:metabolism; D053078:Membrane Potential, Mitochondrial / Q000187:drug effects / Q000502:physiology; D048055:Mitogen-Activated Protein Kinase 8 / Q000378:metabolism; D016755:Proto-Oncogene Proteins c-jun / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D017382:Reactive Oxygen Species / Q000378:metabolism; D000071656:Receptor, Notch3 / Q000378:metabolism*; D015398:Signal Transduction / Q000187:drug effects; D000077204:Temozolomide; D005722:gamma-Glutamylcyclotransferase / Q000494:pharmacology* / Q000633:toxicity
chemical_list: D018906:Antineoplastic Agents, Alkylating; C499374:NOTCH3 protein, human; D016755:Proto-Oncogene Proteins c-jun; D012333:RNA, Messenger; D017382:Reactive Oxygen Species; D000071656:Receptor, Notch3; D003606:Dacarbazine; D048055:Mitogen-Activated Protein Kinase 8; C505407:CASP3 protein, human; C506433:CASP9 protein, human; D053148:Caspase 3; D053453:Caspase 9; C000626964:CHAC1 protein, human; D005722:gamma-Glutamylcyclotransferase; D002118:Calcium; D000077204:Temozolomide
keywords: CHAC1; Glioblastoma multiforme; JNK1/c-JUN pathway; Notch3; Temozolomide (TMZ)