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Pml represses tumour progression through inhibition of mTOR

Rosa Bernardi1, Antonella Papa, Ainara Egia

  • 1Cancer Genetics Program, Beth Israel Deaconess Cancer Center, Division of Genetics, Department of Medicine and Pathology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA. bernardi.rosa@hsr.it

EMBO Molecular Medicine
|March 10, 2011
PubMed

Insights

The promyelocytic leukaemia gene (PML) suppresses tumors by opposing mTOR signaling. Inactivating PML accelerates kidney cancer progression by enhancing mTOR activity, but not cyst formation.

Area of Science:

  • Oncology
  • Molecular Biology
  • Genetics

Background:

  • The promyelocytic leukaemia gene (PML) acts as a tumor suppressor.
  • PML has been shown to counteract mTOR-HIF1α-VEGF signaling pathways during hypoxia.
  • Dysregulation of mTOR signaling is implicated in various cancers, including kidney carcinomas.

Purpose of the Study:

  • To investigate the role of PML-mTOR antagonism in tumor development.
  • To determine the impact of combined PML and Tsc2 inactivation on kidney tumorigenesis.
  • To elucidate the specific roles of mTOR activation in kidney tumor initiation versus progression.

Main Methods:

  • Generation of a mouse model by intercrossing Pml null mice with Tsc2 heterozygous mice.
  • Analysis of aberrant TORC1 activity in pre-tumoral kidneys and kidney lesions.
  • Assessment of tumor progression, biology, and histology in Tsc2/Pml mutant mice.
  • Evaluation of loss of heterozygosity (LOH) rates for the wild-type Tsc2 allele.

Main Results:

  • Combined inactivation of Pml and Tsc2 leads to aberrant TORC1 activity in kidney tumors.
  • This aberrant activity significantly accelerates kidney carcinoma progression, altering tumor biology and histology.
  • PML inactivation reduces the rate of LOH for the wild-type Tsc2 allele.
  • Aberrant TORC1 activity does not accelerate renal cystogenesis in Tsc2/Pml mutants.

Conclusions:

  • mTOR activation is crucial for the progression of kidney tumors, but not for their initiation.
  • PML plays a significant role in suppressing kidney tumor progression through the regulation of mTOR signaling.
  • The findings highlight a critical distinction between mTOR's role in tumor initiation and progression in the kidney.

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