Onionin A, natural compound from onions found effective against Epithelial Ovarian Cancer

Research from Kumamoto University, Japan has found that a natural compound isolated from onions, onionin A (ONA), has several anti-ovarian cancer properties. This discovery is a result of research on the effects of onionin A on a preclinical model of epithelial ovarian cancer (EOC) both in vivo and in vitro. This research comes from the same group that found ONA suppressed pro-tumor activation of host myeloid cells.

Onion A increases anti-tumor immune response by inhibiting
 the immune suppression actions of macrophage and
 myeloid derived suppressor cells (MDSC).
Credit: Dr. Yoshihiro Komohara

Kumamoto University researchers found that onionin A has several effects on epithelial ovarian cancer (EOC). The group’s in vitro experiments showed that epithelial ovarian cancers, which usually proliferate in the presence of pro-tumor M2 macrophages, showed inhibited growth after introduction of onionin A. This was thought to be due to onionin-A’s influence on STAT3, a transcription factor known to be involved in both M2 polarization and cancer cell proliferation. Furthermore, the team found that onionin A inhibited the pro-tumor functions of myeloid derived suppressor cells (MDSC), which are closely associated with the suppression of the anti-tumor immune response of host lymphocytes, by using preclinical sarcoma model. onionin A was also found to enhance the effects of anti-cancer drugs by strengthening their anti-proliferation capabilities. Moreover, experiments on an ovarian cancer murine model that investigated the effects of orally administered onionin A resulted in longer lifespans and inhibited ovarian cancer tumor development. This was considered to be a result of onionin-A’s suppression of M2 polarized macrophages.

The research shows that onionin A reduces the progression of malignant ovarian cancer tumors by interfering with the pro-tumor function of myeloid cells. Onionin A appears to activate anti-tumor immune responses by nullifying the immunosuppressive function of myeloid cells. Onionin A has the potential to enhance existing anti-cancer drugs while also having little to no cytotoxic effects on normal cells. Additionally, side effects in animals have not been seen. With a little more testing, an oral  onionin A supplement should greatly benefit cancer patients.

Citation: Onionin A inhibits ovarian cancer progression by suppressing cancer cell proliferation and the protumour function of macrophages.
Authors: Junko Tsuboki, et., al.
DOI: http://dx.doi.org/10.1038/srep29588
Journal: Nature Scientific Reports
Research funding: Japan Society for the Promotion of Science
Adapted from press release by Kumamoto University