Post by Admin on Feb 3, 2019 15:26:59 GMT
Potentiation of Cannabinoid-Induced Cytotoxicity in Mantle Cell Lymphoma through Modulation of Ceramide Metabolism
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Abstract
Ceramide levels are elevated in Mantle Cell Lymphoma cells following treatment with cannabinoids. Here, we investigated the pathways of ceramide accumulation in the MCL cell line Rec-1 using the stable endocannabinoid analogue R(+)-methanandamide (R-MA). We further interfered with the conversion of ceramide into sphingolipids that promote cell growth. Treatment with R-MA led to increased levels of ceramide species C16, C18, C24 and C24:1 and transcriptional induction of ceramide synthases (CerSs) 3 and 6. The effects were attenuated using SR141716A, which has high affinity to cannabinoid receptor 1 (CB1). The CB1-mediated induction of CerS3 and CerS6 mRNA was confirmed using Win-55,212-2. Simultaneous silencing of CerS3 and CerS6 using siRNA abrogated the R-MA-induced accumulation of C16 and C24. Inhibition of either of the enzymes serine palmiotyl transferase, ceramide synthase, and dihydroceramide desaturase within the de novo ceramide pathway reversed ceramide accumulation and cell death induced by R-MA treatment. In order to enhance the cytotoxic effect R-MA, sphingosine kinase-1 (SK-1) and glucosylceramide synthase (GCS), enzymes that convert ceramide to the pro-proliferative sphingolipids sphingosine-1-phospate and glucosylceramide, respectively, were inhibited. Suppression of either enzyme using inhibitors or siRNA potentiated the decreased viability, induction of cell death and ceramide accumulation induced by R-MA treatment. Our findings suggest that R-MA induces cell death in MCL via CB1-mediated upregulation of the de novo ceramide synthesis pathway. Furthermore, inhibition of SK-1 and GCS potentiated ceramide accumulation and cell death induced by R-MA. This is the first study were the cytotoxic effect of a cannabinoid is enhanced by modulation of ceramide metabolism.
Source: www.ncbi.nlm.nih.gov/pmc/articles/PMC3077284/
Go to:
Abstract
Ceramide levels are elevated in Mantle Cell Lymphoma cells following treatment with cannabinoids. Here, we investigated the pathways of ceramide accumulation in the MCL cell line Rec-1 using the stable endocannabinoid analogue R(+)-methanandamide (R-MA). We further interfered with the conversion of ceramide into sphingolipids that promote cell growth. Treatment with R-MA led to increased levels of ceramide species C16, C18, C24 and C24:1 and transcriptional induction of ceramide synthases (CerSs) 3 and 6. The effects were attenuated using SR141716A, which has high affinity to cannabinoid receptor 1 (CB1). The CB1-mediated induction of CerS3 and CerS6 mRNA was confirmed using Win-55,212-2. Simultaneous silencing of CerS3 and CerS6 using siRNA abrogated the R-MA-induced accumulation of C16 and C24. Inhibition of either of the enzymes serine palmiotyl transferase, ceramide synthase, and dihydroceramide desaturase within the de novo ceramide pathway reversed ceramide accumulation and cell death induced by R-MA treatment. In order to enhance the cytotoxic effect R-MA, sphingosine kinase-1 (SK-1) and glucosylceramide synthase (GCS), enzymes that convert ceramide to the pro-proliferative sphingolipids sphingosine-1-phospate and glucosylceramide, respectively, were inhibited. Suppression of either enzyme using inhibitors or siRNA potentiated the decreased viability, induction of cell death and ceramide accumulation induced by R-MA treatment. Our findings suggest that R-MA induces cell death in MCL via CB1-mediated upregulation of the de novo ceramide synthesis pathway. Furthermore, inhibition of SK-1 and GCS potentiated ceramide accumulation and cell death induced by R-MA. This is the first study were the cytotoxic effect of a cannabinoid is enhanced by modulation of ceramide metabolism.
Source: www.ncbi.nlm.nih.gov/pmc/articles/PMC3077284/