Cathartocytosis: New Cellular ‘Purging’ Process Linked to Healing & Cancer Risk

Cells, when injured, employ a surprisingly direct method of repair – essentially “vomiting” out waste to quickly revert to a more primitive, regenerative state. This newly discovered process, dubbed cathartocytosis, offers a fascinating glimpse into the complex mechanisms of healing, but also raises concerns about its potential role in fueling cancer development. Researchers at Washington University School of Medicine in St. Louis and the Baylor College of Medicine detailed this cellular cleansing process in a recent study published in Cell Reports.

A Previously Unknown Healing Mechanism

For years, scientists have understood that cells respond to injury in several key ways: through programmed self-destruction to clear damaged tissue, and through processes that allow older cells to regain characteristics of younger, more adaptable cells. Cathartocytosis adds another layer to this understanding, revealing a rapid purging mechanism that allows injured cells to shed their specialized machinery and quickly become capable of proliferation and repair. Jeffrey W. Brown, MD, PhD, an assistant professor of medicine at WashU Medicine, likened the process to a cell “decluttering” to focus on regrowth, a shortcut compared to gradual waste degradation.

The discovery stemmed from research into paligenosis, a regenerative injury response first described in 2018 by Jason C. Mills, MD, PhD, now at the Baylor College of Medicine. Paligenosis involves injured cells shifting away from their normal functions and reprogramming themselves to behave like rapidly dividing stem cells – a process crucial for development and tissue repair. Researchers initially believed this cellular decluttering occurred entirely within lysosomes, cellular compartments responsible for waste digestion. However, they observed debris *outside* the cells, prompting further investigation.

Using a mouse model of stomach injury, the team found that this external waste expulsion wasn’t accidental, but a deliberate part of the paligenosis process. The “vomiting” response occurred simultaneously across all stomach cells, confirming it as a standard cellular behavior in response to injury, not a random occurrence. This suggests cathartocytosis isn’t limited to the gastrointestinal tract and may be relevant in other tissues throughout the body.

The Double-Edged Sword of Cellular Cleansing

While cathartocytosis appears to accelerate the healing process, it’s not without potential drawbacks. The rapid expulsion of cellular waste is “messy,” creating an inflammatory environment that, while initially promoting repair, could contribute to chronic injury and even cancer development. Here’s particularly concerning in situations involving ongoing inflammation, such as chronic infections.

“If many older mutated cells revert to stem cell states in an effort to repair an injury – and injuries also often fuel inflammation… there’s an increased risk of acquiring, perpetuating and expanding harmful mutations that lead to cancer as those stem cells multiply,” explained Mills. The ejected cellular waste itself may even serve as a marker for precancerous states, offering a potential avenue for early detection.

This connection to cancer risk is particularly relevant in the context of Helicobacter pylori infections, a common cause of stomach ulcers and an increased risk factor for stomach cancer. Baylor College of Medicine’s Center for Cell and Gene Therapy is actively researching novel therapies for cancer, including those that harness the patient’s own immune system. The researchers hypothesize that cathartocytosis could play a role in perpetuating injury and inflammation in these infections.

Identifying Cathartocytosis and Potential Therapeutic Strategies

Researchers have already begun exploring ways to detect and potentially manipulate this process. Brown and his colleagues at WashU Medicine have developed an antibody that binds to the cellular waste ejected during cathartocytosis, offering a potential tool for identifying when this process is occurring, particularly in large quantities. This could allow for earlier detection of precancerous states and potentially guide treatment decisions.

The ultimate goal, according to Brown, is to find ways to encourage the healing response while simultaneously blocking the potentially harmful effects of chronic cathartocytosis. “If we have a better understanding of this process, we could develop ways to help encourage the healing response and perhaps, in the context of chronic injury, block the damaged cells undergoing chronic cathartocytosis from contributing to cancer formation,” he said.

How Cathartocytosis Fits into Existing Cellular Processes

Cathartocytosis was identified within the broader context of paligenosis, but researchers believe it could be utilized by cells in other situations, including the development of cancer. The process involves the upregulation of genes like Atf3 and Rab7b, which direct lysosomes to dismantle cell parts not needed for regeneration. Previous research, published in 2021, showed that Atf3 activates Rab7b, initiating the autodegradation process. Without Atf3, Rab7b fails to trigger this cellular cleansing.

Looking Ahead: Further Research and Clinical Implications

The discovery of cathartocytosis opens up several avenues for future research. Further studies are needed to determine the extent to which this process occurs in humans and whether it plays a similar role in various tissues and organs. Investigating the specific molecular mechanisms that regulate cathartocytosis could also reveal potential therapeutic targets for promoting healing and preventing cancer.

Researchers are also exploring the possibility of using cathartocytosis as a biomarker for identifying individuals at increased risk of cancer, particularly those with chronic inflammatory conditions. The antibody developed by Brown and his team could be instrumental in this effort, allowing for non-invasive detection of this cellular process.

a deeper understanding of cathartocytosis could lead to the development of novel therapies that harness the power of cellular cleansing to promote healing and prevent disease. However, it’s crucial to remember that this research is still in its early stages, and much work remains to be done before these potential benefits can be realized.