TY - JOUR
T1 - DNA damage induces down-regulation of UDP-glucose ceramide glucosyltransferase, increases ceramide levels and triggers apoptosis in p53-deficient cancer cells
AU - Haynes, Teka Ann S.
AU - Filippov, Valery
AU - Filippova, Maria
AU - Yang, Jun
AU - Zhang, Kangling
AU - Duerksen-Hughes, Penelope J.
N1 - Funding Information:
This work was supported by the National Institutes of Health (N.I.H.) Grant R01 CA095461 (to P.D.H.) from the National Cancer Institute. We are grateful to Dr. B. Vogelstein (Johns Hopkins University) for providing us with the HCT 116 cell lines. We would also like to thank Dr. Nathan Wall for his aid in the flow cytometry experiments.
PY - 2012/7
Y1 - 2012/7
N2 - DNA damaging agents typically induce an apoptotic cascade in which p53 plays a central role. However, absence of a p53-mediated response does not necessarily abrogate programmed cell death, due to the existence of p53-independent apoptotic pathways, such as those mediated by the pro-apoptotic molecule ceramide. We compared ceramide levels before and after DNA damage in human osteosarcoma (U2OS) and colon cancer (HCT116) cells that were either expressing or deficient in p53. When treated with mitomycin C, p53-deficient cells, but not p53-expressing cells, showed a marked increase in ceramide levels. Microarray analysis of genes involved in ceramide metabolism identified acid ceramidase (ASAH1, up-regulated), ceramide glucosyltransferase (UGCG, down-regulated), and galactosylceramidase (GALC, up-regulated) as the three genes most affected. Experiments employing pharmacological and siRNA agents revealed that inhibition of UGCG is sufficient to increase ceramide levels and induce cell death. When inhibition of UGCG and treatment with mitomycin C were combined, p53-deficient, but not p53-expressing cells, showed a significant increase in cell death, suggesting that the regulation of sphingolipid metabolism could be used to sensitize cells to chemotherapeutic drugs.
AB - DNA damaging agents typically induce an apoptotic cascade in which p53 plays a central role. However, absence of a p53-mediated response does not necessarily abrogate programmed cell death, due to the existence of p53-independent apoptotic pathways, such as those mediated by the pro-apoptotic molecule ceramide. We compared ceramide levels before and after DNA damage in human osteosarcoma (U2OS) and colon cancer (HCT116) cells that were either expressing or deficient in p53. When treated with mitomycin C, p53-deficient cells, but not p53-expressing cells, showed a marked increase in ceramide levels. Microarray analysis of genes involved in ceramide metabolism identified acid ceramidase (ASAH1, up-regulated), ceramide glucosyltransferase (UGCG, down-regulated), and galactosylceramidase (GALC, up-regulated) as the three genes most affected. Experiments employing pharmacological and siRNA agents revealed that inhibition of UGCG is sufficient to increase ceramide levels and induce cell death. When inhibition of UGCG and treatment with mitomycin C were combined, p53-deficient, but not p53-expressing cells, showed a significant increase in cell death, suggesting that the regulation of sphingolipid metabolism could be used to sensitize cells to chemotherapeutic drugs.
KW - Apoptosis
KW - Ceramide
KW - Ceramide glucosyltransferase
KW - HPV16 E6
KW - p53
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U2 - 10.1016/j.bbalip.2012.02.002
DO - 10.1016/j.bbalip.2012.02.002
M3 - Article
C2 - 22349266
AN - SCOPUS:84860851547
SN - 1388-1981
VL - 1821
SP - 943
EP - 953
JO - Biochimica et Biophysica Acta - Molecular and Cell Biology of Lipids
JF - Biochimica et Biophysica Acta - Molecular and Cell Biology of Lipids
IS - 7
ER -