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Down-regulation of the Diphthamide biosynthesis protein 2-like gene during retinoid-induced differentiation and

G Liu1, M Wu, G Levi

  • 1Laboratory of Molecular Oncology, Cancer Institute, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, People's Republic of China.

International Journal of Cancer
|October 31, 2000
PubMed

Insights

Retinoids induce changes in diphthamide biosynthesis protein 2-like (DPH2L) gene expression in cancer cells. Down-regulation of DPH2L appears to promote cell differentiation and apoptosis, suggesting it

Area of Science:

  • Molecular biology
  • Cancer research
  • Cellular differentiation

Background:

  • Retinoids, analogs of retinoic acid (RA), are used to treat neoplasias due to their effects on cell proliferation and differentiation.
  • The diphthamide biosynthesis protein 2-like (DPH2L) gene, located on chromosome 17p13.3, was previously considered a candidate tumor-suppressor gene.
  • The precise function of DPH2L in cancer development and progression remains largely uncharacterized.

Purpose of the Study:

  • To investigate the role of DPH2L in retinoid-induced differentiation and apoptosis in human lung cancer cells.
  • To determine if DPH2L functions as a tumor-suppressor gene or a growth regulator.
  • To explore the potential of DPH2L as a prognostic marker for neoplastic diseases.

Main Methods:

  • Utilized mRNA differential display to identify genes modulated by all-trans retinoic acid (RA) in human lung cancer cells.
  • Analyzed DPH2L expression levels in various cancer cell lines following treatment with retinoids (all-trans RA, N-(4-hydroxyphenyl)retinamide) and during cell-cycle arrest.
  • Generated stable expression of a DPH2L-specific anti-sense construct to assess its impact on cell proliferation.

Main Results:

  • Identified a cDNA corresponding to the DPH2L gene.
  • Demonstrated down-regulation of DPH2L during retinoid-induced differentiation and apoptosis across multiple cancer cell lines.
  • Observed inhibition of cell proliferation upon stable expression of a DPH2L-specific anti-sense construct.
  • Found that DPH2L down-regulation correlates with cell-cycle arrest.

Conclusions:

  • DPH2L is not a conventional tumor-suppressor gene; instead, it functions as a growth regulator.
  • Down-regulation of DPH2L may facilitate the transition from cell proliferation to differentiation or apoptosis.
  • DPH2L warrants further investigation as a potential prognostic tool for neoplastic diseases.

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