New plasma therapy fights aggressive soft tissue cancer

Synovial sarcoma, a rare and aggressive form of soft tissue cancer, may soon have a new therapeutic contender. Published in Biomedicines, the team at Osaka Metropolitan University found that plasma-activated medium (PAM)- a solution created by irradiating cell culture medium- significantly inhibited tumour growth both in lab and animal models.

Engineering plasma for medical use

To generate PAM, the team exposed a standard mammalian cell culture medium to five minutes of plasma irradiation, creating a reactive solution with tumour-suppressing properties. The study was conducted by researchers including Graduate School of Medicine student Hana Yao, Associate Professor Hiromitsu Toyoda, Professor Hiroaki Nakamura, and Professor Jun-Seok Oh from the Graduate School of Engineering.

In laboratory tests, human synovial sarcoma cells treated with PAM showed a huge drop in viability. Only 21 percent of cancer cells survived after treatment, a stark contrast to the untreated control group. These findings suggest that PAM disrupts cancer cell function or triggers cell death through mechanisms activated by the reactive species in the plasma-treated solution.

Shrinking tumours without side effects

The researchers also tested PAM in mouse models of synovial sarcoma, delivering daily injections around the tumour over a period of four weeks. The results showed tumours in the treated mice were reduced to 46 percent of their original volume and 59 percent of the weight observed in the control group. Importantly, no major side effects, such as weight loss or reduced appetite, were reported, suggesting a potentially favourable safety profile.

A promising future for plasma-activated medicine

“Not only do our results indicate that PAM has anticancer effects on synovial sarcoma at the cellular and organismal levels, but there also were no obvious side effects such as weight loss or poor appetite observed in the mice,” said Professor Hiromitsu Toyoda.

The team now plans to further develop PAM-based therapies. Their goal is to provide a new treatment option for patients with synovial sarcoma, where current therapies are limited.