Mutations in tumor suppressor genes Vhl and Rassf1a cause DNA damage, chromosomal instability and induce gene...

Area of Science:

• Molecular oncology
• Genomics
• Cellular biology

Background:

• RASSF1A is frequently inactivated in clear cell renal cell carcinoma (ccRCC) via chromosome 3p loss and promoter hypermethylation.
• The VHL gene is also a critical tumor suppressor often inactivated in ccRCC.
• Understanding the combined loss of RASSF1A and VHL function is crucial for modeling ccRCC pathogenesis.

Purpose of the Study:

• To investigate the cellular and molecular consequences of combined Rassf1a and Vhl gene deletion.
• To model the common ccRCC genotype involving loss of RASSF1A and VHL function.
• To determine the impact on genomic integrity, cell proliferation, and gene expression patterns.

Main Methods:

• Deletion of Rassf1a and Vhl genes in mouse embryonic fibroblasts and primary kidney epithelial cells.
• In vivo studies using kidney epithelial cells with combined gene deletion.
• Single-cell RNA-sequencing to analyze gene expression changes.

Main Results:

• Double deletion of Rassf1a and Vhl caused chromosomal segregation defects and micronuclei formation, indicating a role in maintaining genomic integrity.
• Combined deletion in vivo increased proliferation and caused mild tubular disorganization but did not induce kidney tumors.
• Single-cell RNA-sequencing revealed overlapping gene expression changes in response to Rassf1a or Vhl deletion, with additional genes affected by combined deletion.

Conclusions:

• pVHL and RASSF1A are essential for maintaining genomic integrity in kidney cells.
• Loss of RASSF1A function contributes to a ccRCC-characteristic gene expression profile.
• The findings provide insights into the molecular mechanisms underlying ccRCC development.