The role of Claudin-1 in Ha-RasV12 -induced cell junction disruption cell softening and transformation

  • 吳 奕震

Student thesis: Master's Thesis


Our previous studies showed that induction of Ha-RasV12 resulted in cell-cell junction disruption cell softening and subsequently transformation in MK4 cells (derived from Madin-Darby canine kidney MDCK cells) We further found that claudin-1 a “tightening” junction protein were downregulated in mRNA and protein level upon Ha-RasV12 induction Downregulation of claudin-1 has been reported in several types of cancer Claudin-1 was also demonstrated to possess the gastric tumor suppressor activity We wondered whether the suppression of claudin-1 mediated Ha-RasV12-induced cell softening and transformation We first investigated whether suppression of claudin-1 by shRNA elicits cell softening and transformation ability in normal epithelial cells (MK4 and MDCK cells) Knockdown of claudin-1 resulted in cell softening and an increase in migration and anchorage independent growth ability Immunofluorescence staining images showed that claudin-1 knockdown only affect the intensity of ZO-1 but not the localization of β-catenin E-cadherin and ZO-1 Moreover claudin-1 knockdown decreased the intensity of junctional actin filaments especially at apical pole of the cell We further checked whether overexpression of Green Fluorescence Protein (GFP)-claudin-1 abrogates Ha-RasV12-induced cell junction disruption cell softening and transformation in MK4 cells Overexpression of claudin-1 partially stunted Ha-RasV12-induced cell scattering but not cell softening U0126 the MEK1/2 inhibitors significantly abolished Ha-RasV12-induced claudin-1 downregulation but not cells softening Our data supported that knockdown of claudin-1 elicited cell softening and transformation However to complete Ha-RasV12-induced cell softening and transformation still needs the cooperation of other Ha-RasV12 activated factors
Date of Award2014 Aug 27
Original languageEnglish
SupervisorMing-Jer Tang (Supervisor)

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