title: ATF4 and N-Myc coordinate glutamine metabolism in MYCN-amplified neuroblastoma cells through ASCT2 activation.
abstract: Amplification of the MYCN gene in human neuroblastoma predicts poor prognosis and resistance to therapy. We previously showed that MYCN-amplified neuroblastoma cells constantly require large amounts of glutamine to support their unabated growth. However, the identity and regulation of the transporter(s) that capture glutamine in MYCN-amplified neuroblastoma cells and the clinical significance of the transporter(s) in neuroblastoma diagnosis remain largely unknown. Here, we performed a systemic glutamine influx analysis and identified that MYCN-amplified neuroblastoma cells predominantly rely on activation of ASCT2 (solute carrier family 1 member 5, SLC1A5) to maintain sufficient levels of glutamine essential for the TCA cycle anaplerosis. Consequently, ASCT2 depletion profoundly inhibited glutaminolysis, concomitant with a substantial decrease in cell proliferation and viability in vitro and inhibition of tumourigenesis in vivo. Mechanistically, we identified ATF4 as a novel regulator which coordinates with N-Myc to directly activate ASCT2 expression. Of note, ASCT2 expression, which correlates with that of N-Myc and ATF4, is markedly elevated in high-stage neuroblastoma tumour samples compared with low-stage ones. More importantly, high ASCT2 expression is significantly associated with poor prognosis and survival of neuroblastoma patients. In aggregate, these findings elucidate a novel mechanism depicting how cell autonomous insults (MYCN amplification) and microenvironmental stresses (ATF4 induction) in concert coordinate ASCT2 activation to promote aggressive neuroblastoma progression, and establish ASCT2 as a novel biomarker in patient prognosis and stratification.
authors.affiliation: Department of Pharmacology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, People's Republic of China.
authors.forename: Ping
authors.initials: P
authors.lastname: Ren
authors.forename: Ming
authors.initials: M
authors.lastname: Yue
authors.forename: Daibiao
authors.initials: D
authors.lastname: Xiao
authors.forename: Ruijuan
authors.initials: R
authors.lastname: Xiu
authors.forename: Lei
authors.initials: L
authors.lastname: Gan
authors.forename: Hudan
authors.initials: H
authors.lastname: Liu
authors.forename: Guoliang
authors.initials: G
authors.lastname: Qing
mesh_terms: D051701:Activating Transcription Factor 4 / Q000378:metabolism*; D026962:Amino Acid Transport System ASC / Q000378:metabolism*; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000502:physiology; D005784:Gene Amplification / Q000235:genetics; D015972:Gene Expression Regulation, Neoplastic; D016259:Genes, myc / Q000235:genetics*; D005973:Glutamine / Q000378:metabolism; D006801:Humans; D015778:Minor Histocompatibility Antigens; D009447:Neuroblastoma / Q000175:diagnosis* / Q000378:metabolism; D011379:Prognosis
chemical_list: C497109:ATF4 protein, human; D026962:Amino Acid Transport System ASC; D015778:Minor Histocompatibility Antigens; C420506:SLC1A5 protein, human; D005973:Glutamine; D051701:Activating Transcription Factor 4
keywords: ASCT2; ATF4; N-Myc; glutamine; tumour metabolism