Published in:
01-01-2014 | Original Article
Bortezomib-induced apoptosis in cultured pancreatic cancer cells is associated with ceramide production
Authors:
Lei Gong, Bo Yang, Ming Xu, Bo Cheng, Xuejun Tang, Ping Zheng, Yan Jing, Gao-jue Wu
Published in:
Cancer Chemotherapy and Pharmacology
|
Issue 1/2014
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Abstract
Purpose
The proteasome inhibitor bortezomib (PS-341) has displayed significant efficiency against pancreatic cancer cells. However, the underlying mechanisms are not fully understood. Here, we tested if ceramide production was involved in the bortezomib’s effect.
Methods
Two transformed pancreatic cancer cell lines (PANC-1 and Mia) and the primary pancreatic cancer cells were used. Cell death was analyzed by MTT viability assay and trypan blue staining. Cell apoptosis was analyzed by Histone DNA-ELISA assay and Annexin V FACS. Western blots were used to test signal protein changes. The cellular ceramide level after bortezomib treatment was also determined.
Results
In cultured pancreatic cancer cells, bortezomib increased cellular ceramide production to promote cell apoptosis. The ceramide de novo synthase inhibitor fumonisin B1 (F-B1) suppressed bortezomib-induced ceramide production and apoptosis, while exogenously added C6-ceramide facilitated bortezomib-induced pancreatic cancer cell death. Meanwhile, 1-phenyl-2-decanoylamino-3-morpholino-1-propanol (PDMP), the inhibitor of glucosylceramide synthetase as well as the sphingosine kinase 1 inhibitors (SKI-II and SKI-IV), facilitated bortezomib-induced ceramide production and subsequent cell apoptosis. Further, bortezomib-induced pro-apoptotic c-Jun N-terminal kinase (JNK) activation was also associated with ceramide production. JNK activation by bortezomib was suppressed by F-B1, but was enhanced by SKI-II and PDMP in pancreatic cancer cells. Finally, C6-ceramide, SKI-II, and PDMP dramatically enhanced bortezomib-induced cytotoxicity in primary cultured pancreatic cancer cells.
Conclusions
We found that bortezomib-induced apoptosis was associated with ceramide production in primary and transformed pancreatic cancer cells.