Robust p53 phenotypes and prospective downstream targets in telomerase-immortalized human cells

Area of Science:

• Molecular Biology
• Cancer Research
• Cell Biology

Background:

• Wild-type TP53 is often lost in cancers, hindering studies on its full tumor-suppressive functions.
• Commonly used cancer models with wild-type TP53 may not fully represent p53's capabilities.
• Previous models like HCT116 colorectal cancer (CRC) cells, despite wild-type TP53, lack certain p53 phenotypes.

Purpose of the Study:

• To investigate the functional impact of restoring wild-type p53 in TP53-mutant colorectal cancer cells.
• To explore p53-dependent phenotypes in a non-cancerous cell line (hTERT-RPE1) to understand p53's broader roles.
• To identify novel p53 target genes with potential clinical significance in cancer.

Main Methods:

• Restoration of p53 in the TP53-mutant DLD-1 CRC cell line.
• Disruption of TP53 in immortalized hTERT-RPE1 cells.
• Analysis of p53-dependent phenotypes including cell proliferation, senescence, and response to ionizing radiation (IR).
• Transcriptomic analysis to identify p53-responsive genes.

Main Results:

• Restoring p53 in DLD-1 cells reduced proliferation, induced senescence, and increased sensitivity to IR.
• TP53 disruption in hTERT-RPE1 cells revealed significant p53-dependent phenotypes, suggesting p53 loss is selected for during culture.
• A p53-responsive transcriptome in hTERT-RPE1 cells was identified, serving as a model for diverse experimental systems.
• Novel p53 targets, including ALDH3A1 (aldehyde detoxification, ROS metabolism) and NECTIN4 (cell adhesion, overexpressed in tumors), were discovered.

Conclusions:

• Wild-type p53 actively suppresses tumor growth and enhances treatment sensitivity.
• The hTERT-RPE1 cell line is a valuable model for studying p53 function and identifying novel targets.
• ALDH3A1 and NECTIN4 represent potential therapeutic targets due to their roles in detoxification, metabolism, and their prevalence in tumors.