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Cigarette smoke suppresses the ubiquitin-dependent degradation of OLC1

Xiaojing Zhang1, Ting Xiao, Shujun Cheng

  • 1State Key Laboratory of Molecular Oncology, Cancer Institute (Hospital), Peking Union Medical College and Chinese Academy of Medical Sciences, Beijing 100021, China.

Biochemical and Biophysical Research Communications
|March 29, 2011
PubMed

Insights

Cigarette smoke condensate increases OLC1 protein in lung cancer by blocking its ubiquitination and degradation via the anaphase promoting complex (APC). This study reveals a novel mechanism linking smoking to OLC1 regulation in lung cancer.

Area of Science:

  • Oncology
  • Molecular Biology
  • Biochemistry

Background:

  • The gene overexpressed in lung cancer 1 (OLC1) is highly expressed in lung tumors of smokers.
  • Mechanisms linking cigarette smoke to OLC1 regulation are poorly understood.

Purpose of the Study:

  • Investigate how cigarette smoke condensate (CSC) regulates OLC1 in lung cancer cells.
  • Elucidate the molecular pathways involved in CSC-mediated OLC1 modulation.

Main Methods:

  • Treatment of lung cancer cells with CSC.
  • Analysis of OLC1 mRNA and protein levels.
  • Assessment of OLC1 ubiquitination.
  • Co-immunoprecipitation assays to study protein interactions.

Main Results:

  • CSC increased OLC1 protein levels in a dose- and time-dependent manner, without affecting OLC1 mRNA.
  • CSC treatment inhibited OLC1 ubiquitination.
  • CSC impaired the binding of OLC1 to CDC20, CDH1, and APC2, key components of the ubiquitin-proteasome system.

Conclusions:

  • CSC regulates OLC1 protein levels in lung cancer cells by inhibiting its ubiquitination and subsequent degradation.
  • This regulation occurs through interference with the anaphase promoting complex (APC) ubiquitin ligase pathway.

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