Involvement of 67-kDa laminin receptor-mediated myosin phosphatase activation in antiproliferative effect of epigallocatechin-3-O-gallate at a physiological concentration on Caco-2 colon cancer cells

Biochem Biophys Res Commun. 2008 Jun 20;371(1):172-6. doi: 10.1016/j.bbrc.2008.04.041. Epub 2008 Apr 25.

Abstract

Previously we reported that 67-kDa laminin receptor (67LR) mediates epigallocatechin-3-O-gallate (EGCG)-induced cell growth inhibition and reduction of myosin regulatory light chain (MRLC) phosphorylation at Thr-18/Ser-19, which is important for cytokinesis. Here, we found that human colon adenocarcinoma Caco-2 cells exhibited higher expression level of 67LR and EGCG at a physiologically achievable concentration (1 microM) significantly accumulated the cells in G(2)/M phase without affecting expression of Wnt-signaling components. We also found that myosin phosphatase targeting subunit 1 (MYPT1) phosphorylation at Thr-696, which inhibits myosin phosphatase and promotes MRLC phosphorylation, was reduced in response to 1 microM EGCG. 67LR knockdown by RNA interference abolished the inhibitory effects of 1 microM EGCG on cell cycle progression and the phosphorylation of MRLC and MYPT1. These results suggest that through 67LR, EGCG at a physiological concentration can activate myosin phosphatase by reducing MYPT1 phosphorylation and that may be involved in EGCG-induced cell growth inhibition.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adenocarcinoma / metabolism*
  • Antineoplastic Agents / pharmacology*
  • Caco-2 Cells
  • Catechin / analogs & derivatives*
  • Catechin / pharmacology
  • Cell Cycle / drug effects
  • Cell Proliferation / drug effects
  • Colonic Neoplasms / metabolism*
  • HeLa Cells
  • Humans
  • Myosin-Light-Chain Phosphatase / antagonists & inhibitors
  • Myosin-Light-Chain Phosphatase / metabolism*
  • Phosphorylation / drug effects
  • Receptors, Laminin / antagonists & inhibitors
  • Receptors, Laminin / genetics
  • Receptors, Laminin / metabolism*

Substances

  • Antineoplastic Agents
  • Receptors, Laminin
  • Catechin
  • epigallocatechin gallate
  • Myosin-Light-Chain Phosphatase
  • PPP1R12A protein, human