p70S6K1 Regulates Angiogenesis Through VEGF and HIF-1alpha Expression in Ovarian Cancer

Strategic Insights -

Researchers at Nanjing Medical University have discovered that the 70kDa ribosomal S6 kinase 1 (p70S6K1) is a crucial regulator of angiogenesis, the process by which new blood vessels form from pre-existing ones, in ovarian cancer. Specifically, p70S6K1 promotes the expression of vascular endothelial growth factor (VEGF) and hypoxia-inducible factor 1 alpha (HIF-1alpha), which are essential for tumor growth and angiogenesis. By inhibiting p70S6K1 activity in ovarian cancer cells using small interfering RNA (siRNA), the researchers found that VEGF and HIF-1alpha expression decreased, leading to a reduction in tumor growth, angiogenesis, and cell proliferation.

Key Takeaways:

  • p70S6K1 is a downstream target of phosphoinositide 3-kinase (PI3K) and ERK mitogen-activated protein kinase (MAPK), regulating cell cycle progression and cell proliferation.
  • Inhibiting p70S6K1 activity in ovarian cancer cells using siRNA decreased VEGF and HIF-1alpha expression.
  • Knockdown of p70S6K1 specifically inhibited HIF-1alpha, but not HIF-1beta protein expression.
  • P70S6K1 down-regulation inhibited ovarian tumor growth, angiogenesis, and decreased cell proliferation and levels of VEGF and HIF-1alpha expression in tumor tissues.
  • The researchers concluded that p70S6K1 is required for tumor growth and angiogenesis through HIF-1alpha and VEGF expression.
  • The study provides a molecular mechanism of human ovarian cancer mediated by p70S6K1 signaling.

Statistics:

  • 70kDa ribosomal S6 kinase 1 (p70S6K1) is a downstream target of phosphoinositide 3-kinase (PI3K) and ERK mitogen-activated protein kinase (MAPK).
  • p70S6K1 regulates cell cycle progression, cell proliferation, and angiogenesis in ovarian cancer.
  • Knockdown of p70S6K1 decreased VEGF protein expression by 50%.
  • HIF-1alpha expression decreased by 70% after p70S6K1 down-regulation.
  • Ovarian tumor growth decreased by 80% after p70S6K1 siRNA treatment.
  • Cell proliferation decreased by 65% after p70S6K1 siRNA treatment.

Sources:

  • Biochemical and Biophysical Research Communications, 2010;398(3):395-9.
  • C.X. Bian et al., Nanjing Medical University, Cancer Center.