Novel involvement of leukotriene B4 receptor 2 through ERK activation by PP2A down-regulation in leukotriene B4-induced keratin phosphorylation and reorganization of pancreatic cancer cells

Abstract

Perinuclear reorganization via phosphorylation of specific serine residues in keratin is involved in the deformability of metastatic cancer cells. The level of leukotriene B₄ is high in pancreatic cancers. However, the roles of LTB₄ and its cognate receptors in keratin reorganization of pancreatic cancers are not known. LTB₄ dose-dependently induced phosphorylation and reorganization of Keratin 8 (K8) and these processes were reversed by LY255283 (BLT2 antagonist). BLT2 agonists such as Comp A and 15(S)-HETE also induced phosphorylation of serine 431 in K8. Moreover, Comp A-induced K8 phosphorylation and reorganization were blocked by LY255283. Gene silencing of BLT2 suppressed Comp A-induced K8 phosphorylation and reorganization in PANC-1 cells. Over-expression of BLT2 promoted K8 phosphorylation. Comp A promoted the migration of PANC-1 cells in a dose-dependent manner, and LY255283 blocked Comp A-induced migration, respectively. PD98059 (ERK inhibitor) suppressed Comp A-induced phosphorylation of serine 431 and reorganization of K8. Gene silencing of BLT2 suppressed the expression of pERK, and over-expression of BLT2 increased the expression of pERK even without Comp A. Comp A induced the expression of active ERK (pERK) and BLT2. These inductions were blocked by PD98059. Comp A decreased PP2A expression and hindered the binding of PP2A to the K8, leading to the activation of ERK. PD98059 suppressed the Comp A-induced migration of PANC-1 cells and BLT2 over-expression-induced migration of PANC-1 cells. Overall, these results suggest that BLT2 is involved in LTB(4)-induced phosphorylation and reorganization through ERK activation by PP2A downregulation, leading to increased migration of PANC-1 cells.

12-O-Tetradecanoylphorbol-13-Acetate Induces Keratin 8 Phosphorylation and Reorganization via Expression of Transglutaminase-2

“…The effect of TPA on K8 phosphorylation was examined using specific monoclonal antibodies for K8 Ser23, Ser73, and Ser431 in PANC-1, a pancreatic cancer cell line well-suited for use in keratin phosphorylation and reorganization studies (Park et al ., 2012; Byun et al ., 2013). TPA dose-dependently induced K8 phosphorylation and Tgase-2 expression in the PANC-1 cells (Fig.…”

“…2). K8 is an intermediate filament consisting of a conserved central coiled-coil α-helical rod domain flanked by N- (head) and C-terminal (tail) domains (Park et al ., 2012). For K8, three phosphorylation sites have been reported, namely K8pSer23, K8pSer73, and K8pSer431.…”

“…In addition to catalyzing Ca 2+ -dependent transamidation reactions, it can bind and hydrolyze GTP/GDP with a similar affinity and catalytic rate as the α subunit of large heterotrimeric G proteins and small Ras-type G proteins (Park et al ., 2011). The selective expression of Tgase-2 in chemoresistant and metastatic cancer cells, such as pancreatic, lung and ovarian tumors, as well as its ability to promote cell survival and invasion make it a promising therapeutic target (Park et al ., 2012). In previous report, we demonstrated that Tgase-2 is involved in SPC-induced K8 phosphorylation and reorganization (Park et al ., 2011).…”

Alox5 Blockade Eradicates JAK2V617F-Induced Polycythemia Vera in Mice

“…Increasing evidence shows that the metabolites of the arachidonic acid cascade play a role in epithelial cell proliferation and tumorigenesis (31, 32). A known function of Alox5 is to produce inflammatory metabolites called leukotrienes.…”

A remarkable Activity of Steroid Biosynthesis in Captopril Preserved Leydig Cells of Mice Implicated Leukotriene B4 and Gonadotropin Releasing Hormones in vitro

“…It would therefore be very advantageous to be able to provide low molecular weight inhibitors of LTB4 biosynthesis (5) which preferably exhibit activity in vivo at desirably low concentrations (11 and 10) Furthermore the LTB4 -induced phosphorylation and reorganization through ERK activation in cells (32), the captopril inhibits LTB4 collapse the phosphorylation coupling cascades with sequel of upset of viability and steroidogenic yield.…”