Park Mi Kyung, Park Youngran, Shim Jaegal, Lee Hye Ja, Kim Sanghee, Lee Chang Hoon
College of Pharmacy, Dongguk University, Goyang 410-820, Republic of Korea.
Biochim Biophys Acta. 2012 Dec;1823(12):2120-9. doi: 10.1016/j.bbamcr.2012.09.004. Epub 2012 Sep 24.
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.
通过角蛋白中特定丝氨酸残基的磷酸化实现的核周重组参与了转移性癌细胞的变形能力。胰腺癌中白三烯B₄水平较高。然而，白三烯B₄及其同源受体在胰腺癌角蛋白重组中的作用尚不清楚。白三烯B₄剂量依赖性地诱导角蛋白8（K8）的磷酸化和重组，这些过程可被LY255283（BLT2拮抗剂）逆转。Comp A和15(S)-HETE等BLT2激动剂也诱导K8中丝氨酸431的磷酸化。此外，Comp A诱导的K8磷酸化和重组被LY255283阻断。BLT2基因沉默抑制了Comp A诱导的PANC-1细胞中K8磷酸化和重组。BLT2的过表达促进了K8磷酸化。Comp A以剂量依赖性方式促进PANC-1细胞的迁移，而LY255283分别阻断了Comp A诱导的迁移。PD98059（ERK抑制剂）抑制了Comp A诱导的丝氨酸431磷酸化和K8重组。BLT2基因沉默抑制了pERK的表达，而BLT2的过表达即使在没有Comp A的情况下也增加了pERK的表达。Comp A诱导活性ERK（pERK）和BLT2的表达。这些诱导被PD98059阻断。Comp A降低了PP2A的表达并阻碍了PP2A与K8的结合，导致ERK激活。PD98059抑制了Comp A诱导的PANC-1细胞迁移和BLT2过表达诱导的PANC-1细胞迁移。总体而言，这些结果表明，BLT2通过下调PP2A激活ERK参与白三烯B₄诱导的磷酸化和重组，导致PANC-1细胞迁移增加。
