Researchers at the Class of 1942 Professor of Chemistry Matthew D. Shoulders' lab have identified a cellular mechanism that enables cancer cells to survive and potentially thrive despite drug treatment, facilitating the development of aggressive mutations. This discovery, published in Molecular Cell, highlights an interaction between molecular biology and evolutionary dynamics, focusing on the TP53 (p53) anti-cancer gene.
The Role of p53 and Mutations
The p53 protein, known as the "guardian of the genome," is responsible for preventing damaged cells from dividing. It is the most frequently mutated gene in cancer. Some critical mutations are "dominant-negative," meaning they not only cease to function but also inhibit healthy p53 within the cell.
Proteins like p53 must fold into specific 3D shapes to function. Normally, mutations that disrupt this shape lead to protein degradation.
The Proteostasis Network and HSF1
A specialized network of cellular chaperones, collectively forming the proteostasis network, assists proteins in achieving their correct shapes. This network is often upregulated in cancer cells.
- Hypothesis: Increased activity of these protein-folding networks could allow cancer cells to tolerate more mutations than normal cells.
- Key Regulator: Heat Shock Factor 1 (HSF1) is a master regulator of the proteostasis network, upregulating it to create supportive protein-folding environments under stress. While dormant in healthy cells, HSF1 is frequently active in cancer.
Experimental Findings
To investigate this, the research team developed a cancer cell line enabling on-demand HSF1 activity amplification. They then used a technique to express various singly mutated versions of p53.
- Results: When HSF1 was amplified, cancer cells demonstrated an improved ability to manage