Inhibition of sphingosine kinase-2 ablates androgen resistant prostate cancer proliferation and survival

Background: endogenous sphingolipid signaling has been shown to play an important role in prostate cancer endocrine resistance. methods: the novel sphk2 inhibitor,abc294640,was used to explore sphk signaling in androgen resistant prostate cancer cell death signaling. results: it dose-dependently decreased pc-3 and lncap cell viability,ic50 of 28 × 6.1 μm (p < 0.05) and 25 × 4.0 μm (p < 0.05),respectively. abc294640 was more potent in long-term clonogenic survival assays; ic50 of 14 × 0.4 μm (p < 0.05) in pc-3 cells and 12 × 0.9 μm (p < 0.05) in lncap cells. intrinsic apoptotic assays failed to demonstrate increased caspase-9 activity. ki-67 staining demonstrated decreased proliferation by 50 × 8.4% (p < 0.01) in pc-3 cells. conclusions: sphk2 inhibition decreases androgen resistant prostate cancer viability,survival,and proliferation independently of the intrinsic apoptotic pathway. findings are in contrast to recent observations of abc29460 acting dependently on the intrinsic pathway in other endocrine resistant cancer cell lines. © 2014 institute of pharmacology,polish academy of sciences. published by elsevier urban & partner sp. z o.o. all rights reserved.