title: Sphingosine kinase 1 inhibition sensitizes hormone-resistant prostate cancer to docetaxel.
abstract: It has recently been shown that docetaxel chemotherapy is effective in prolonging life in patients with prostate cancer (PCa). We have investigated potential ways of increasing the effectiveness of chemotherapy in this disease. We have previously reported that sphingosine kinase 1 (SphK1) inhibition is a key step in docetaxel-induced apoptosis in the PC-3 PCa cell line and that pharmacologicalSphK1 inhibition is chemosensitizing in the docetaxel-resistant PCa LNCaP cell line. In this study we have addressed the mechanism of docetaxel-induced apoptosis of PC-3 cells and identified SphK1-dependent and -independent components. We have shown that SphK1 inhibition by docetaxel is a two-step process involving an initial loss of enzyme activity followed by a decrease in SphK1 gene expression. Using hormoneresistant PC-3 and DU145 PCa cells we have demonstrated that both pharmacological and siRNA-mediated SphK1 inhibition leads to a four-fold decrease in the docetaxel IC50 dose. This work points out to potential ways of increasing the effectiveness of chemotherapy for PCa by SphK1 inhibition.
authors.affiliation: Department of Oncology, Imperial College London, London, United Kingdom.
authors.forename: Lysann
authors.initials: L
authors.lastname: Sauer
authors.forename: Joao
authors.initials: J
authors.lastname: Nunes
authors.forename: Vishal
authors.initials: V
authors.lastname: Salunkhe
authors.forename: Lenka
authors.initials: L
authors.lastname: Skalska
authors.forename: Takafumi
authors.initials: T
authors.lastname: Kohama
authors.forename: Olivier
authors.initials: O
authors.lastname: Cuvillier
authors.forename: Jonathan
authors.initials: J
authors.lastname: Waxman
authors.forename: Dmitry
authors.initials: D
authors.lastname: Pchejetski
mesh_terms: D000970:Antineoplastic Agents / Q000627:therapeutic use*; D017209:Apoptosis / Q000187:drug effects; D015153:Blotting, Western; D020169:Caspases / Q000378:metabolism; D002453:Cell Cycle / Q000187:drug effects; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects; D000077143:Docetaxel; D019008:Drug Resistance, Neoplasm; D005434:Flow Cytometry; D006801:Humans; D008297:Male; D009376:Neoplasms, Hormone-Dependent / Q000188:drug therapy* / Q000201:enzymology / Q000235:genetics; D017853:Phosphotransferases (Alcohol Group Acceptor) / Q000037:antagonists & inhibitors* / Q000235:genetics / Q000378:metabolism; D011471:Prostatic Neoplasms / Q000188:drug therapy* / Q000201:enzymology / Q000235:genetics; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D034741:RNA, Small Interfering / Q000494:pharmacology; D020133:Reverse Transcriptase Polymerase Chain Reaction; D043823:Taxoids / Q000627:therapeutic use*; D000099157:Sphingosine Kinase
chemical_list: D000970:Antineoplastic Agents; D020169:Caspases; D000077143:Docetaxel; D017853:Phosphotransferases (Alcohol Group Acceptor); D012333:RNA, Messenger; D034741:RNA, Small Interfering; D043823:Taxoids; D000099157:Sphingosine Kinase