Functional consequence of the p53 codon 72 polymorphism in colorectal cancer

Area of Science:

• Genetics and Molecular Biology
• Cancer Research
• Oncology

Background:

• The p53 codon 72 polymorphism is linked to colorectal cancer (CRC) risk, prognosis, and health disparities.
• Understanding the functional impact of this polymorphism is critical for CRC research.

Purpose of the Study:

• To investigate the functional consequences of the p53 codon 72 polymorphism in colorectal cancer.
• To determine the role of different p53 phenotypes in CRC cell behavior and signaling pathways.

Main Methods:

• Constructed plasmids expressing various p53 phenotypes (R72wt, R72273Cys, P72wt, P72273Cys).
• Utilized the Caco2 CRC cell line for in vitro studies and CRC xenografts in SCID mice.
• Sequenced CRC specimens and xenografts for p53 codon 72 polymorphism and evaluated protein signaling mechanisms.

Main Results:

• The P72wt phenotype significantly increased cell survival compared to the R72wt phenotype.
• P72wt induced activation of p38 and RAF/MEK/ERK MAP kinases, with higher CREB activation in P72-expressing tumors.
• CRC metastatic lesions showed increased phospho-CREB, indicating P72wt promotes CRC metastasis.

Conclusions:

• The P72 variant contributes to colorectal cancer aggressiveness and metastasis.
• Overexpression of P72 in CRC, particularly in African-American patients, suggests a role in cancer health disparities.
• Further research into P72's role can inform targeted therapies and reduce health disparities.