“Forever” chemicals cause cancer cells to spread

When colon cancer cells are exposed to two different types of “forever chemicals” in the lab, they are likely to accelerate the cancer’s growth, a new study suggests.

The new study examined exposure levels similar to those found in firefighters and other individuals who regularly handle perfluoroalkyl and polyfluoroalkyl substances (PFAS). Blood levels of PFAS in firefighters are higher than in the general population due to frequent exposure to firefighting foam, which contains PFAS chemicals.

Firefighters are more likely than the general population to develop and die from various types of cancer, including colon cancer.

Environmental factors are thought to be associated with about 80 percent of CRC cases.

In new research, exposure to PFAS in the lab prompted CRC cells to migrate to new sites, suggesting a possible role in the spread of cancer (metastasis) in living organisms. For further clarification, Carolyn Johnson, an epidemiologist at Yale University, said, “This does not prove the presence of a malignant tumor, but it does indicate an increase in mobility, which is characteristic of metastasis,” says “Scientific Alert.” Website cited from the journal “Environmental Science and Technology”. .

PFAS are man-made chemicals that rely on carbon-fluorine bonds. As the term “permanent chemicals” suggests, these bonds are very strong and resistant to degradation, which is why PFAS are commonly used in many types of products. Unfortunately, it allows it to remain in the environment for years at ever-increasing concentrations.

“PFASs are a widespread class of persistent organic pollutants that are increasing worldwide. They are frequently detected in the environment such as drinking water, indoor dust, cleaning products, and paints,” says co-first author Ji Cheng, a physiologist at Yale University. Found in materials, however, the dangers of PFAS are often unclear—due to the variety of compounds found in them.”

These chronic chemicals persist in the environment, and research shows that high levels of exposure are associated with adverse health effects in humans and animals.

In this context, perfluorooctanoic acid (PFOA), a widely used PFAS, was classified as a human carcinogen by the International Agency for Research on Cancer in November 2023. Perfluorooctanesulfonic acid (PFOS), another common PFAS, is also known to be carcinogenic to humans.

To study how this affects invasive CRC, Cheng, Johnson and their colleagues used lab-grown CRC cells and metabolites; It is a process that measures the amount of metabolites and thousands of small molecules such as amino acids, fats and proteins.

In this, Johnson says, “we look at patterns that occur within an at-risk group or group of patients, and then try to develop a hypothesis about why someone develops a disease or develops a disease.” He added, “metabolism is one of the only tools where you can measure an environmental exposure in the same model as a biological effect.” Two types of CRC cells, shaped into balls called spheroids, were used in the experiments; The wild-type KRAS gene was present in one species, while the other had a common mutation in the KRAS gene that was specifically associated with aggressive CRC. “When exposed to PFOS and PFOA, the cells showed increased motility and a greater tendency to spread.”

In a differential experiment with CRC cells grown in a flat layer, a line was scratched down the middle to separate them. When the chemicals were introduced, the cells grew and moved back toward each other.

To go deeper, the researchers studied the chemicals’ effects on cell metabolism. Exposure to PFAS altered various metabolites important for cell function, such as amino acids and fatty acids, as well as signaling proteins associated with metastasis. Common anti-inflammatory and cancer-protective substances in CRC cells were also downregulated after exposure. Certain differences are more common in mutated cells, which means that cancers carrying this mutation are more likely to spread when exposed to PFAS.

These study findings suggest that exposure to high levels of PFOS and PFOA may increase the risk of CRC prevalence in real-life settings.

The research team concludes: “This information is important for workers in jobs where they are exposed to high levels of chemicals, and monitoring these substances is essential to protect their health, as is future clinical research. .”

“Many laboratory studies cannot be translated to humans, but I believe it is first important to understand the mechanisms of how they actually affect the growth of cancer cells,” Johnson concludes.