Cannabis stem extract suppressed bisphenol A (BPA)-induced proliferation in human breast cancer cells while interfering with estrogen-receptor signaling linked to the effect, according to a new laboratory study.
The study, published September 23 in Ecotoxicology and Environmental Safety, examined ethanol extract made from Cannabis sativa stems, an under-studied part of the plant that researchers noted lacks detectable delta-9 THC. The research team included scientists from Chung-Ang University, Dongguk University and Gyeongguk National University in South Korea and the University of Massachusetts Amherst.
Researchers focused on BPA, a widely encountered endocrine-disrupting chemical capable of activating estrogen receptor alpha (ERα). Previous research has linked BPA exposure with estrogen-receptor signaling and increased proliferation in certain breast cancer cell models.
For the new study, researchers used VM7Luc4E2 cells, an ERα-positive human breast cancer cell line. Cells were exposed to BPA for 48 hours and then treated for another 24 hours with cannabis stem ethanol extract or individual compounds identified in the extract.
BPA produced a dose-dependent increase in viable cell density. Treatment with the cannabis stem extract abolished that BPA-induced increase in cell proliferation. The extract also demonstrated ERα-antagonistic activity, with researchers calculating an IC20 of 8.7 micrograms per milliliter and an IC50 of 87.5 micrograms per milliliter.
Researchers identified three compounds — cyclopentane-1,2-dione (CPD), 4-vinylguaiacol (4-VG) and 4-([1E]-hydroxy-1-propenyl)-2-methoxyphenol (4-HMP) — that showed ERα-antagonistic activity. Each also suppressed the increase in breast cancer cell proliferation produced by BPA.
Additional experiments suggested the extract worked through multiple mechanisms. Cannabis stem extract and all three compounds reduced BPA-induced phosphorylation of p38, part of the MAPK signaling pathway involved in cell proliferation. Meanwhile, 4-VG and 4-HMP significantly reduced the movement of ERα into the cell nucleus, while CPD appeared to operate through a different mechanism.
The researchers said the findings could ultimately support further investigation of cannabis stems, which are often discarded as agricultural waste or used primarily for fiber, as a source of biologically active compounds. They also noted that cannabis extracts contain numerous phytochemicals, meaning the observed effects cannot necessarily be attributed to a single substance.
The findings remain preliminary. The research was conducted entirely in cultured cells, with no human participants or live animals. Researchers cautioned that the concentrations producing effects in the laboratory should not be interpreted as concentrations necessarily achievable in the human body, and that bioavailability, metabolic stability and long-term safety were not evaluated. Further animal and human-exposure research will be needed to determine whether the findings have practical therapeutic significance.
The study was funded by the National Research Foundation of Korea, Korea’s Ministry of Food and Drug Safety and a Chung-Ang University graduate research scholarship. The authors reported no competing financial interests.
I could not find any previous Marijuana Herald article covering this study, including searches by the DOI, exact study title and the cannabis-stem/BPA/breast-cancer combination. It appears to be new for you.
