Researchers in Switzerland say a pesticide designed to make grapes and kiwifruit bigger can also slow mesothelioma cell growth.
The EPA approved forchlorfenuron (FCF) in 2004. Farmers use it to help grapes and kiwifruit grow bigger, break less easily, and last longer in cold storage.
But new research at the University of Fribourg suggests that the chemical has the opposite effect on mesothelioma cell growth. Mesothelioma cells exposed to FCF are less likely to live and spread. The researchers say this could be a promising step toward a new kind of mesothelioma treatment.
Forchlorfenuron and Mesothelioma Cell Growth
The EPA classifies FCF as a plant growth regulator. According to the EPA fact sheet, FCF is a cytokinin which “improves fruit size, fruit set, cluster weight, and cold storage in grapes and kiwifruits.” FCF appears to help fruit by strengthening the cell wall.
But animal cells respond differently. In animal cells, proteins called septins help provide a scaffold on which other proteins can attach. Mesothelioma cell growth depends heavily on septins. They are critical in the building of RNA, which directs many cellular functions.
FCF appears to damage mesothelioma cells by keeping septins from doing their job.
A New Kind of Mesothelioma Treatment?
The Swiss scientists theorized that FCF’s effect on septins could inhibit mesothelioma cell growth. To test the idea, they exposed mesothelioma cells and several other kinds of cancer cells to the chemical in the lab.
“Exposure to FCF strongly inhibited proliferation of human and mouse (most efficiently epithelioid) malignant mesothelioma cells and all other tumor cells in a concentration-dependent manner and led to cell cycle arrest and cell death,” writes author Beat Schwaller.
The group confirmed that the inhibition of septin 7 was the reason for the effect on mesothelioma cell growth. They were especially encouraged to see that FCF had the same effect in live animals. There were no major complications.
The researchers concluded that this new understanding of FCF could lead to better mesothelioma treatments. It may also help other cancers that depend on septins.
“FCF’s rather low systemic toxicity might warrant for an extended search for other related and possibly more potent FCF analogues,” they write.
Mesothelioma is one of the rarest but most aggressive cancers. By the time most patients receive a diagnosis, mesothelioma cell growth is usually out of control.
Mesothelioma is highly resistant to standard cancer treatments. This has forced researchers like the Swiss team to think outside the box to develop new therapies.
Blum, W, et al, “The phytohormone forchlorfenuron decreases viability and proliferation of malignant mesothelioma cells in vitro and in vivo”, December 10, 2019, Oncotarget, Epub ahead of print, http://www.oncotarget.com/index.php?journal=oncotarget&page=article&op=view&path=27341&path=88803