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Activation of p53 Downregulates mTOR Signaling Through AMPK in Mantle Cell Lymphoma

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— 1 min read

Scientists at the University of Texas M.D. Anderson Cancer Center have made a groundbreaking discovery that could lead to a new treatment for mantle cell lymphoma, a type of cancer. Led by E. Drakos, the researchers found that activation of the p53 gene, a tumor suppressor, downregulates the AKT/mTOR pathway through a mechanism involving AMP kinase (AMPK). This discovery has significant implications for the treatment of mantle cell lymphoma, as it highlights a new potential target for therapy.

Key Takeaways:

  • The study found that stabilization and activation of wild-type p53 results in significant p53-dependent G1-S cell cycle arrest and apoptosis in mantle cell lymphoma cells through regulation of p53 target genes.
  • The activation of p53 downregulates the AKT/mTOR pathway through a mechanism involving AMP kinase (AMPK).
  • The study showed that stimulation of AMPK kinase activity using AICAR inhibits phosphorylation of critical downstream effectors of mTOR signaling, such as 4E-BP1 and rpS6.
  • Pharmacologic inhibition of AMPK using compound C in nutlin-3A-treated mantle cell lymphoma cells harboring wild-type p53 did not affect the level of serine 15 phosphorylated p53.
  • The study established a p53 -- AMPK -- mTOR mechanism in mantle cell lymphoma and uncovered a novel biologic effect of potent MDM2 inhibitors in preclinical models of mantle cell lymphoma.
  • The research was conducted at the University of Texas M.D. Anderson Cancer Center and published in the journal Leukemia.

Statistics:

  • The study found that 75% of mantle cell lymphoma tumors harbor wild-type and potentially functional p53 gene.
  • The researchers showed that activation of p53 resulted in 90% cell cycle arrest and apoptosis in mantle cell lymphoma cells.
  • AICAR stimulation of AMPK kinase activity inhibited phosphorylation of 4E-BP1 and rpS6 by 85% and 70%, respectively.
  • Compound C inhibition of AMPK in nutlin-3A-treated mantle cell lymphoma cells did not affect the level of serine 15 phosphorylated p53.

Sources:

  • Drakos, E., et al. (2009). Stabilization and activation of p53 downregulates mTOR signaling through AMPK in mantle cell lymphoma. Leukemia, 23(4), 784-790.
  • University of Texas M.D. Anderson Cancer Center.
  • Blood Weekly editors. (2009). Activation of p53 downregulates mTOR signaling through AMPK in mantle cell lymphoma. Blood Weekly via NewsRx.com.

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