ATM/ATR and SMAD3 pathways contribute to 3-indole-induced G₁ arrest in cancer cells and xenograft models

Anticancer Res. 2011 Jan;31(1):203-8.

Abstract

Background: 3-Indole inhibits lung cancer growth by apoptosis. Here, the growth inhibition mechanism besides apoptosis was further characterized.

Materials and methods: The Comet assay was used to examine 3-indole-induced DNA damage. Cell cycle distribution and protein expression were analyzed using flow cytometry, Western blotting and immunohistochemistry in cell and animal models.

Results: 3-Indole induced dose-dependent DNA damage, which was reversed by reactive oxygen species (ROS) inhibitor in lung cancer cells. Cell cycle G₁ arrest was observed in the 3-indole-treated cells. DNA damage-responsive proteins involved in the ataxia telangiectasia mutated/ataxia telangiectasia and Rad3-related (ATM/ATR) pathway and G₁ regulation proteins such as p21 and SMA- and MAD-related protein 3 (SMAD3) were induced in the cell models. The altered expression of ATM, ATR, checkpoint kinase 2 (CHK2), and cell division cycle 25 homolog A (CDC25A) were confirmed in xenograft models. Importantly, the 3-indole-induced ATM/ATR and transforming growth factor (TGF)-β/SMAD pathways were attenuated by ROS inhibitor.

Conclusion: 3-Indole causes DNA damage and triggers ATM/ATR and SMAD3 signaling pathways to arrest lung cancer cells at the G₁-phase.

MeSH terms

  • Animals
  • Apoptosis / drug effects
  • Ataxia Telangiectasia Mutated Proteins
  • Blotting, Western
  • Carcinoma, Non-Small-Cell Lung / drug therapy*
  • Carcinoma, Non-Small-Cell Lung / metabolism
  • Carcinoma, Non-Small-Cell Lung / pathology
  • Cell Cycle Proteins / metabolism*
  • Comet Assay
  • DNA Damage / drug effects
  • DNA-Binding Proteins / metabolism*
  • Female
  • G1 Phase / drug effects*
  • Humans
  • Immunoenzyme Techniques
  • Indoles / pharmacology*
  • Lung Neoplasms / drug therapy*
  • Lung Neoplasms / metabolism
  • Lung Neoplasms / pathology
  • Mice
  • Mice, Nude
  • Protein Serine-Threonine Kinases / metabolism*
  • Reactive Oxygen Species / metabolism
  • Signal Transduction / drug effects
  • Smad3 Protein / metabolism*
  • Tumor Cells, Cultured
  • Tumor Suppressor Protein p53 / metabolism
  • Tumor Suppressor Proteins / metabolism*
  • Xenograft Model Antitumor Assays

Substances

  • Cell Cycle Proteins
  • DNA-Binding Proteins
  • Indoles
  • Reactive Oxygen Species
  • SMAD3 protein, human
  • Smad3 Protein
  • TP53 protein, human
  • Tumor Suppressor Protein p53
  • Tumor Suppressor Proteins
  • indole
  • ATM protein, human
  • ATR protein, human
  • Ataxia Telangiectasia Mutated Proteins
  • Atm protein, mouse
  • Protein Serine-Threonine Kinases