The role of T-fimbrin in the response to DNA damage: silencing of T-fimbrin by small interfering RNA sensitizes human liver cancer cells to DNA-damaging agents

Int J Oncol. 2005 Oct;27(4):933-40.

Abstract

Fimbrins (also known as plastins) are actin-binding proteins of the cortical cytoskeleton present in all cells and conserved from yeast to mammals. We previously reported that the up-regulation of T-fimbrin, a fimbrin isoform, in association with G2 arrest following DNA damage and that a lack of T-fimbrin expression shortens the radiation-induced G2 arrest in Chinese hamster ovarian cells. In this study, we further investigated the role of T-fimbrin in DNA-damage response using a panel of human liver cancer cell lines and small interfering RNA technology. T-fimbrin was differentially expressed in human liver cancer cell lines. Colony formation assays revealed that cell lines lacking T-fimbrin expression were highly sensitive to DNA damage compared to cell lines that express T-fimbrin. Using siRNA designed to target T-fimbrin, we demonstrated that silencing endogenous T-fimbrin causes a marked increase in the cellular sensitivity to VP-16 and UV irradiation. Moreover, T-fimbrin deletion abrogated UV-mediated cell cycle checkpoint, and consequently led to increased apoptotic cell death in resistant cells. These findings suggest that the status of T-fimbrin expression may be a useful molecular marker for predicting the responsiveness of cancer cells to treatment with chemotherapeutic drugs.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Actins / chemistry
  • Antineoplastic Agents / pharmacology
  • Antineoplastic Agents, Phytogenic / pharmacology
  • Apoptosis
  • Azacitidine / analogs & derivatives
  • Azacitidine / pharmacology
  • Carcinogens / pharmacology
  • Cell Cycle
  • Cell Line, Tumor
  • Cell Separation
  • Cytoskeleton / metabolism
  • DNA Damage*
  • DNA Methylation
  • Decitabine
  • Etoposide / pharmacology
  • Flow Cytometry
  • G2 Phase
  • Gene Expression Regulation, Neoplastic*
  • Gene Silencing
  • Humans
  • Immunoblotting
  • Liver Neoplasms / metabolism
  • Liver Neoplasms / pathology*
  • Membrane Glycoproteins / physiology*
  • Microfilament Proteins / physiology*
  • Microscopy, Fluorescence
  • Protein Isoforms
  • RNA Interference
  • RNA, Small Interfering* / metabolism
  • Reverse Transcriptase Polymerase Chain Reaction
  • Time Factors
  • Transfection
  • Ultraviolet Rays

Substances

  • Actins
  • Antineoplastic Agents
  • Antineoplastic Agents, Phytogenic
  • Carcinogens
  • Membrane Glycoproteins
  • Microfilament Proteins
  • Protein Isoforms
  • RNA, Small Interfering
  • plastin
  • Etoposide
  • Decitabine
  • Azacitidine