ATP-binding cassette ABCC1 is involved in the release of sphingosine 1-phosphate from rat uterine leiomyoma ELT3 cells and late pregnant rat myometrium

• Published in: Cellular signalling 2011-12, Vol.23 (12), p.1997-2004
• Main Authors: Tanfin, Zahra, Serrano-Sanchez, Martin, Leiber, Denis
• Format: Article
• Language: English
• Subjects: ABCC1; Animals; Cell Line, Tumor; COX2; Cyclooxygenase 2 - genetics; Cyclooxygenase 2 - metabolism; Enzyme Assays; Female; Gene Expression; Gene Knockdown Techniques; GTP-Binding Protein alpha Subunits, Gi-Go - metabolism; Kinases; Leiomyoma; Lysophospholipids - metabolism; Mitogen-Activated Protein Kinase 1 - metabolism; Mitogen-Activated Protein Kinase 3 - metabolism; Multidrug Resistance-Associated Proteins - antagonists & inhibitors; Multidrug Resistance-Associated Proteins - genetics; Multidrug Resistance-Associated Proteins - metabolism; Myometrium; Myometrium - metabolism; Phosphotransferases (Alcohol Group Acceptor) - genetics; Phosphotransferases (Alcohol Group Acceptor) - metabolism; Pregnancy; Propionates - pharmacology; Protein Kinase C - metabolism; Quinolines - pharmacology; Rats; Rats, Wistar; Receptors, Lysosphingolipid - metabolism; RNA Interference; S1P; Sphingosine - analogs & derivatives; Sphingosine - metabolism; Uterine Neoplasms
• ISSN: 0898-6568; 1873-3913
• DOI: 10.1016/j.cellsig.2011.07.010

Sphingosine 1-phosphate (S1P), a bioactive lipid generated by sphingosine kinases (SphK1/2), initiates different signalling pathways involved in physiological and pathological processes. We previously demonstrated that in rat myometrium at late (day 19) gestation, SphK1 increases the expression of COX2 via S1P generation and release. In rat uterine leiomyoma cells (ELT3), SphK1/S1P axis controls survival and proliferation. In the present study we demonstrate that PDBu activates SphK1 but not SphK2. SphK1 activation requires PKC and MAPK ERK1/2. S1P produced by PDBu is released in the medium. PDBu-induced S1P export is abolished by Ro-318220 and BIM (PKC inhibitors), by U0126 and PD98059 (MEK inhibitors), SKI-II (SphKI/2 inhibitor) and SphK1-siRNA, suggesting the involvement of PKC, ERK and SphK1 respectively. The release of S1P is insensitive to inhibitors of ATP Binding Cassette (ABC)A1 and ABCB1 transporters, but is abolished when ABCC1 transporters are inhibited by MK571 or down-regulated by ABCC1-siRNA. PDBu increases COX2 expression that is blocked by the inhibition of PKC, ERK1/2, SphK1, and when cells are treated with MK571 or transfected with ABCC1-siRNA. The induction of COX2 by the S1P release due to PDBu or by exogenous S1P involves S1P2 receptors coupled to Gi. In myometrium from rat at late gestation, the release of S1P is also strongly reduced when SphK and ABCC1 are inhibited. The data reveal that in rat leiomyoma cells and late pregnant rat myometrium, the release of S1P involves a similar signalling pathway and occurs through ABCC1. ► Mechanism of the S1P release from pregnant rat myometrium (M) and leiomyoma (ELT3). ► In ELT3 cells, S1P is released subsequently to the activation of SphK1 by PDBu. ► The activation of PKC and ERK is involved in SphK1 activation and S1P release. ► S1P by PDBu released up-regulates COX2 expression via S1P2 receptors coupled to Gi. ► In ELT3 and M, S1P export involves a similar signalling pathway and occurs via ABCC1.