Study Finds CBD Suppressed Growth and Invasion of Human Glioma Cells, While Reducing Tumor Growth in a Mouse Model

Cannabidiol (CBD) significantly suppressed the growth, migration and invasion of glioma cells while reducing tumor burden in mice, according to a new study that identified a potential mechanism behind the cannabinoid’s anticancer effects.

The study, published in BioMed Research International, was conducted by researchers affiliated with Anhui Medical University, Lu’an People’s Hospital and the Beijing Institute of Basic Medical Sciences. Researchers examined whether CBD limits glioma progression partly by suppressing lysyl oxidase-like 2 (LOXL2), a protein involved in extracellular-matrix remodeling and cancer-cell invasiveness.

Researchers tested CBD against human U87 and mouse GL261 glioma cells. CBD produced dose- and time-dependent reductions in cell viability and reduced the cells’ ability to form colonies. Treatment also caused cells to accumulate in the G1 phase of the cell cycle and significantly increased apoptosis, or programmed cell death.

CBD also markedly reduced the migration and invasion of both glioma cell lines. The treatment lowered expression of MMP2 and MMP9, proteins associated with tissue invasion, while increasing TIMP3, which inhibits matrix metalloproteinases.

RNA sequencing identified 1,247 genes whose expression changed following CBD treatment, including 642 that increased and 605 that decreased. LOXL2 emerged as a prominent CBD-responsive molecule and was significantly reduced following treatment. Analysis of public patient datasets found that higher LOXL2 expression was associated with more aggressive glioma characteristics and shorter overall survival.

Further experiments strengthened the proposed connection. Silencing LOXL2 reproduced key effects of CBD by reducing glioma-cell migration and invasion, while artificially increasing LOXL2 partially counteracted CBD’s anti-invasive effects. The researchers emphasized that this partial reversal suggests LOXL2 is one contributor to CBD’s activity rather than its only molecular target.

Researchers then tested CBD in 12 mice implanted with GL261 glioma cells in the brain. Six mice received 20 milligrams of CBD per kilogram of body weight daily beginning seven days after tumor implantation, while six received a control treatment. Imaging showed significantly lower tumor burden in CBD-treated mice on days 14, 21 and 28. No significant differences in body weight were observed between the groups.

Tumors from CBD-treated mice also showed reduced markers of proliferation, extracellular-matrix remodeling and mesenchymal characteristics, along with increased markers of apoptosis.

The findings remain preclinical and do not establish that CBD treats glioma in humans. The researchers said larger animal studies, patient-derived models, pharmacokinetic studies and additional work establishing how CBD affects LOXL2 will be needed before clinical translation.

“In summary,” the researchers concluded, the findings support LOXL2 as a functional mediator of CBD’s broader effects against glioma, while noting that the study does not establish direct CBD-LOXL2 binding or identify LOXL2 as CBD’s sole target.