1. Targeting glucosylceramide synthase synergizes with C6-ceramide nanoliposomes to induce apoptosis in natural killer cell leukemia.
- Author
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Watters, Rebecca J., Fox, Todd E., Tan, Su-Fern, Shanmugavelandy, Sriram, Choby, Jacob E., Broeg, Kathleen, Liao, Jason, Kester, Mark, Cabot, Myles C., Loughran, Thomas P., and Liu, Xin
- Subjects
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KILLER cells , *CYTOLOGICAL research , *LEUKEMIA , *SPHINGOLIPIDS , *GLUCOSYLCERAMIDES , *URIDINE diphosphate - Abstract
Natural killer (NK) cell leukemia is characterized by clonal expansion of CD3 − NK cells and comprises both chronic and aggressive forms. Currently no effective treatment exists, thus providing a need for identification of novel therapeutics. Lipidomic studies revealed a dysregulated sphingolipid metabolism as evidenced by decreased levels of overall ceramide species and increased levels of cerebrosides in leukemic NK cells, concomitant with increased glucosylceramide synthase (GCS) expression. GCS, a key enzyme of this pathway, neutralizes pro-apoptotic ceramide by transfer of a uridine diphosphate (UDP)-glucose. Thus, we treated both rat and human leukemic NK cells in combination with: (1) exogenous C6-ceramide nanoliposomes in order to target mitochondria and increase physiological pro-apoptotic levels of long chain ceramide, and (2) 1-phenyl-2-palmitoylamino-3-morpholino-1-propanol (PPMP), an inhibitor of GCS. Co-administration of C6-ceramide nanoliposomes and PPMP elicited an increase in endogenous long-chain ceramide species, which led to cellular apoptosis in a synergistic manner via the mitochondrial intrinsic cell death pathway in leukemic NK cells. [ABSTRACT FROM AUTHOR]
- Published
- 2013
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