Premium
Knockout of Fatty Acyl‐CoA Synthetase ACSVL3 in Glioma Cells Produces Diverse Metabolic Alterations in Non‐Lipid Pathways
Author(s) -
Watkins Paul,
Shi Xiaohai,
Kolar Elizabeth,
Clay Emily,
Liu Yanqiu
Publication year - 2019
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.2019.33.1_supplement.652.23
Subject(s) - lipid metabolism , cell cycle , chemistry , glut1 , glioma , fatty acid synthesis , apoptosis , microbiology and biotechnology , biology , biochemistry , glucose transporter , fatty acid , endocrinology , cancer research , insulin
Knockout (KO) of the fatty acid‐activation enzyme very long chain acyl‐CoA synthetase 3 (ACSVL3; SLC27A3) in glioblastoma cells reduced their malignant growth properties both in vitro and in xenografts. KO U87 glioma cells grew at a slower rate, became adherence‐dependent, and were less invasive than parental U87 cells. KO cells produced fewer, slower‐growing subcutaneous and intracranial tumors when implanted in NOD‐SCID mice. To understand the mechanisms underlying these changes, we investigated several possibilities. We first hypothesized that lack of ACSVL3 might reduce the rate of incorporation of labeled fatty acids into membrane phospholipids; however, no differences were observed. We then investigated the possibility that lack of ACSVL3 affected either apoptosis or autophagy, but detected no differences in these processes between control and KO U87 cells. We next examined cell cycle, and found that KO produced significant changes. In non‐synchronized cells, parental U87 cells were mainly in G0/G1, while ACSVL3 KO cells were mainly in S‐phase. After synchronization by serum starvation, both U87 and KO cells started out mainly in G0/G1, but by 12 hours ACSVL3 KO cells shifted significantly toward S‐phase. Consistent with this finding, the levels of several cyclins and cyclin‐dependent kinases were found to be altered in KO cells. In addition to effects on lipid metabolism, proteomic and metabolomics profiling indicated that ACSVL3 KO produced changes in glucose and energy metabolism. Even though protein levels of glucose transporters GLUT1 and GLUT3 were reduced by KO, cellular uptake of labeled 2‐deoxyglucose was unaffected. Glucose oxidation to CO2 was reduced 40% by ACSVL3 depletion, and the cellular glucose level was 25% higher in KO cells. Glycolytic enzymes were upregulated by KO, but metabolic intermediates were essentially unchanged. Surprisingly, lactate production and the levels of both LDHA and LDHB were elevated by ACSVL3 KO. The activity of the pentose phosphate pathway was found to be lower in KO cells. Citric acid cycle enzymes, electron transport chain complexes, and ATP synthase protein levels were all reduced by ACSVL3 depletion. Mitochondria were elongated in KO cells, but had a more punctate morphology in U87 cells. We conclude that beneficial effects of ACSVL3 depletion in human glioblastoma cells are the result of alterations in diverse metabolic processes that are not directly related to fatty acid and/or lipid metabolism. Support or Funding Information Supported by Institutional Funds. This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal .