Genetic and functional studies implicate HIF1α as a 14q kidney cancer suppressor gene

Area of Science:

• Oncology
• Molecular Biology
• Genetics

Background:

• Clear cell renal carcinoma (ccRCC) frequently involves deletions on chromosome 3p (VHL gene) and 14q.
• The VHL tumor suppressor protein (pVHL) regulates hypoxia-inducible factors (HIFs).
• HIF2α is an oncoprotein in kidney cancer, while HIF1α's role is less understood.

Purpose of the Study:

• To investigate the role of HIF1α in ccRCC development.
• To determine if HIF1α is a tumor suppressor gene targeted by 14q deletions.

Main Methods:

• Analysis of homozygous deletions at the HIF1α locus in ccRCC cell lines.
• Assessment of HIF1α function in wild-type and deleted cell lines.
• Evaluation of HIF1α expression and mutation status in patient tumors.

Main Results:

• Focal, homozygous deletions of the HIF1α locus were identified in ccRCC cell lines.
• Wild-type HIF1α suppressed tumor growth, whereas altered HIF1α did not.
• Downregulation of HIF1α in proficient lines promoted tumor growth.
• HIF1α activity was diminished in 14q-deleted cancers, with loss-of-function mutations.

Conclusions:

• Chromosome 14q deletion is common in ccRCC and associated with poor prognosis.
• HIF1α acts as a kidney cancer suppressor gene, targeted by 14q loss.