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Overexpression of Plk3 causes morphological change and cell growth suppression in Ras pathway-activated cells

Masato Iida1, Takanori Sasaki, Hideya Komatani

  • 1Department of Oncology, Tsukuba Research Institute, Banyu Pharmaceutical Co., Ltd, Okubo 3, Tsukuba, Ibaraki 300-2611, Japan.

Journal of Biochemistry
|June 27, 2009
PubMed

Insights

Polo-like kinase 3 (Plk3) overexpression inhibits cell growth by altering cytoskeleton organization. This effect is amplified in cells with activated Ras pathways, suggesting Plk3

Area of Science:

  • Cell Biology
  • Molecular Biology
  • Biochemistry

Background:

  • Polo-like kinase 3 (Plk3) is involved in cell cycle regulation.
  • The precise mechanism of Plk3's role in cell growth inhibition remains to be fully elucidated.
  • Ras proteins are known regulators of the actin cytoskeleton and cell growth.

Purpose of the Study:

  • To investigate the mechanism by which Plk3 overexpression inhibits cell growth.
  • To determine the role of Plk3's kinase activity in its cellular effects.
  • To examine the interplay between Plk3 and Ras in regulating cell adhesion and growth.

Main Methods:

  • Overexpression of Plk3 in 293T cells.
  • Assessment of cell morphology, actin organization, and adhesion.
  • Long-term colony-forming assays to evaluate cellular growth.
  • Co-transfection of Plk3 and Ras in relevant cell lines.

Main Results:

  • Plk3 overexpression induced cell rounding, altered F-actin organization, and caused cellular detachment in a kinase-dependent manner.
  • Plk3 overexpression suppressed long-term cellular growth without inducing apoptosis.
  • Co-transfection of Plk3 and Ras synergistically reduced cell adhesion compared to Plk3 alone.
  • Plk3 overexpression led to prolonged growth suppression in Ras-transformed NIH3T3 cells.

Conclusions:

  • Plk3 activation contributes to cytoskeleton re-organization, leading to growth inhibition.
  • The growth-suppressive effects of Plk3 are more pronounced in cells with activated Ras signaling.
  • Plk3 may represent a therapeutic target for cancers with aberrant Ras pathway activation.

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