Follows the cells

Microplastics could help cancer spread

(Bild: Pcess609 - stock.adobe.com)

Microplastics can apparently promote the spread of cancer in the body - this is the oppressive finding of a recent study. According to the study, the plastic follows the cells as they divide and could therefore promote metastases.

Researchers estimate the weekly intake of plastic particles at up to five grams. This is roughly equivalent to the weight of a credit card. However, how the now unavoidable plastic behaves in the body is still largely unknown. A Viennese research team from the University of Vienna and MedUni Vienna has now reported in the journal "Chemosphere" on evidence that mini-particles can even be passed on during cell division and may promote the spread of cancer.

Targeting where plastic usually ends up
The researchers focused on the gastrointestinal tract, where ingested plastic particles often end up. One of the key questions here is whether, how long and in what quantity they can potentially remain there and what consequences this has.

It is almost impossible to escape microplastics - they have even been detected on the polar ice caps.

(Bild: Pcess609 - stock.adobe.com)

To this end, the scientists focused on four cell types that occur in colorectal tumors - a type of bowel cancer - in humans. The team then exposed these different cell lines to plastic particles of various sizes, according to the paper.

Organelles bite their teeth out
There were already indications from other studies that very small particles with a diameter of less than two or one micrometer - from the latter range onwards, they are referred to as nanoplastics - can penetrate cells well, explained study leader Verena Pichler. Her study also showed that MNPs, like other waste products in the body, are taken up by tiny "organs" within the cells - the lysosomes.

These so-called organelles are actually responsible for breaking down foreign bodies. However, the microplastic particles - the scientists used polystyrene beads - were a tough nut to crack.

Research is still in its infancy
For Pichler, it was "hardly surprising" that such small particles could so easily become embedded in cells. The researcher comes from the field of medical drug design, where the approach of using nanoparticles to target drugs into cells has been pursued for some time.

Cancer cells can travel via the bloodstream to other areas of the body, colonize there and form metastases.

(Bild: Krone KREATIV, stock.adobe.com)

So why nanoplastics and nanoparticles should differ here is not necessarily obvious. This also applies to the fact that the two areas of research in this field are currently still hardly exchanging information with each other, as the topic of "microplastics in human health" has only been promoted for around five years, according to Pichler.

Plastic is passed on in the body
Accordingly, the scientist and her colleagues now describe "for the first time" that the plastic can even be passed on to newly formed cells during cell division. Due to the high uptake and the long retention time in the examined tissue, "the examined particles fulfill two of three characteristics in toxicology that are classified as substances of concern under the EU chemicals regulation REACH," says the neurochemist.

Facilitates "free swimming" of tumor cells
In addition, the team found initial indications that tumor cells contaminated with plastic can migrate more easily in the body and thus virtually help in the formation of cancer offshoots (metastases). Initial laboratory data from follow-up investigations support the hypothesis that the nature of the cells changes slightly.

The penetrating or trapped plastic particles appear to make the outer skin of the cells - the cell membrane - less firm. This in turn makes it more difficult for the cells to grow together and makes it easier for the tumor cells to "swim around freely" in the body, explained Pichler.

Researcher: "Further studies urgently needed"
"Given the ubiquity of plastics in the environment and the persistent exposure of humans to even the smallest plastic particles, further studies are urgently needed to investigate long-term effects in particular," says Lukas Kenner from MedUni Vienna. For Pichler, in view of the findings, "it can be assumed that MNP has a chronic toxicity".