Researchers in the lab of Michael Sigal at the Max Delbrück Center and Charité – Universitätsmedizin Berlin have elucidated the role of the p53 gene in ulcerative colitis. The study, published in Science Advances, suggests a potential new drug target to stop disease progression to cancer.
A team of researchers led by Kimberly Hartl, a graduate student at the Berlin Institute for Medical Systems Biology of the Max Delbrück Center (MDC-BIMSB) and Charité – Universitätsmedizin, have shed new light on the role of the p53 tumor suppressor gene in the pathogenesis of ulcerative colitis (UC) – an inflammatory bowel disease that afflicts an estimated five million people worldwide and that is linked to an increased risk of colon cancer. The research points to a new way to stop the disease from progressing. The study was published in the journal Science Advances.
"In patients with ulcerative colitis who are at high risk for developing cancer, we could potentially target aberrant cells and get rid of them early, before any cancer occurs," says Professor Michael Sigal, Group Leader of the Gastrointestinal Barrier, Regeneration Carcinogenesis lab at MDC-BIMSB, Head of Luminal Gastroenterology at Charité, and a senior author of the paper.
A key role for p53
Ulcerative colitis affects the large intestine, specifically areas called "crypts," tube-like glands within the epithelial tissue that lines the intestine. Crypts contain stem cells and other cell types that maintain the health and normal function of the colon, such as absorbing nutrients or secreting mucus.
When the colon is injured, epithelial crypt cells enter a "repair mode." They begin to proliferate rapidly to fix the injury. However, in patients with UC and UC-related colon cancers, these cells become stuck in repair mode, which scientists refer to as a "regenerative cell state." As a result, there are too few mature cells. Consequently, the colon struggles to function normally, which triggers even more stem cell proliferation in a toxic feedback loop.
In the current study, Hartl found this defective repair mechanism is linked to a non-functional p53 gene, which plays a key role in regulating the cell cycle and in repairing DNA.
"If there is no p53, cells remain in a proliferative state," Sigal explains.
Existing tests to find precancerous lesions in patients with UC such as colonoscopies can identify visible lesions that sometimes are not easy to remove, says Sigal. This study could be a first step in developing molecular tools for a less invasive diagnostic test that would allow physicians to identify the aberrant cells much earlier, even before visible alterations occur, he adds.
Regeneration gone hay-wire
To study the repair process, the researchers developed a three-dimensional organoid – a mini organ – model of the colon grown from mouse stem cells.
Together with specialists in DNA and RNA sequencing as well as proteomics and metabolomic technology at the Max Delbrück Center, they found that cells in organoids lacking p53 are stuck in the regenerative state. Thus, the cells metabolize glucose more rapidly via the process of glycolysis. By contrast, when p53 is active, it diminishes glucose metabolism and signals cells to re-enter a healthy state.
The scientists then treated the organoids with compounds that interfere with glycolysis to test whether they can target these highly proliferative cells. They found that cells that lacked the p53 gene were more vulnerable to this treatment than normal cells. "With organoids, we can identify very specific agents that can target metabolic pathways and point us toward potentially new therapeutics to selectively target mutated cells," Hartl adds.
The next step is to transfer these findings to the human setting. The researchers are also now studying the repair process in more detail with the goal of developing more simple methods to identify cells with defective p53 genes in colon tissue.
"Once we have a simple method of identifying these individual cells in colon tissues, we could perform clinical studies to selectively kill them, and then analyze whether this is associated with a lower risk of developing cancer," says Sigal.
Further information
Proteomics and Metabolomics Platform
Literature
Kimberly Hartl, Safak Bayram, Alexandra Wetzel, et al. (2024):"P53 terminates the regenerative fetal-like state after colitis-associated injury." Science Advances. DOI: 10.1126/sciadv.adp8783
Max Delbrück Center
The Max Delbrück Center for Molecular Medicine in the Helmholtz Association (Max Delbrück Center) is one of the world's leading biomedical research institutions. Max Delbrück, a Berlin native, was a Nobel laureate and one of the founders of molecular biology. At the locations in Berlin-Buch and Mitte, researchers from some 70 countries study human biology – investigating the foundations of life from its most elementary building blocks to systems-wide mechanisms. By understanding what regulates or disrupts the dynamic equilibrium of a cell, an organ, or the entire body, we can prevent diseases, diagnose them earlier, and stop their progression with tailored therapies. Patients should be able to benefit as soon as possible from basic research discoveries. This is why the Max Delbrück Center supports spin-off creation and participates in collaborative networks. It works in close partnership with Charité – Universitätsmedizin Berlin in the jointly-run Experimental and Clinical Research Center (ECRC), the Berlin Institute of Health (BIH) at Charité, and the German Center for Cardiovascular Research (DZHK). Founded in 1992, the Max Delbrück Center today employs 1,800 people and is 90 percent funded by the German federal government and 10 percent by the State of Berlin.
