Phenethyl isothiocyanate (PEITC) is a naturally occurring isothiocyanate. Brussels sprouts, watercress, radishes and capers all get their characteristic flavors from isothiocyanates. Noting that PEITC has shown promising results against several other types of cancer, doctors at Universite Nantes tested it alone and in combination with cisplatin on nine lines of pleural mesothelioma and on healthy mesothelial cells. Some of the cells had been co-cultured with M2 macrophages, immune system cells that promote cell proliferation.
Both PEITC and cisplatin were toxic to mesothelioma cells and that toxicity increased as the dose increased. But together, the two compounds were even more powerful, not only increasing each other’s anti-cancer effects but preventing the emergence of treatment resistant mesothelioma cells. Just as importantly, the normal mesothelial cells showed no sensitivity to the PEITC/cisplatin combination, suggesting that the combination would be less likely to cause serious side effects if used in clinical practice.
Finally, the tests showed that the PEITC/cisplatin combination was unaffected by the M2 macrophages that sometimes interfere with mesothelioma treatment. “Cisplatin-PEITC combination thus represents a promising strategy to induce a selective toxicity towards malignant cells,” writes study author Dr. Iza Denis of Universite Nantes.
Selectivity is an important quality for any cancer treatment because the ability to single out or “select” cancer cells means a drug is less likely to damage healthy cells. Many of the complications associated with mesothelioma treatment are the result of damage to healthy cells.
Denis, I, et al, “Cisplatin in combination with Phenethyl Isothiocyanate (PEITC), a potential new therapeutic strategy for malignant pleural mesothelioma”, Oncotarget, October 18, 2014, Epub ahead of print