Study: CBC and CBD Combo Shrinks Drug-Resistant Triple-Negative Breast Cancer Tumors in Lab and Animal Models

OG article by Anthony Martinelli

February 13, 2026

A peer-reviewed study from Florida A&M University, published in Drug Delivery and Translational Research, demonstrates that combining the non-intoxicating cannabinoids cannabichromene (CBC) and cannabidiol (CBD) produces significant anti-tumor effects against doxorubicin-resistant triple-negative breast cancer (TNBC), one of the most aggressive and treatment-resistant forms of breast cancer.

Researchers tested the combination on doxorubicin-resistant MDA-MB-231 TNBC cells in both 2D and 3D lab models. Combination index analysis confirmed strong synergy between CBC and CBD. The treatment arrested cancer cells in the G0/G1 cell cycle phase and reduced invasive capacity by approximately 55% in Matrigel invasion assays.

In animal trials using BALB/c nude mice with implanted resistant tumors, the CBC (10 mg/kg) and CBD (20 mg/kg) combination reduced tumor volume roughly twice as effectively as either cannabinoid alone and four times more than untreated controls. Western blot analysis revealed suppression of key oncogenic pathways, including MEK/ERK and PI3K/AKT/mTOR, along with reduced expression of Cyclin D1, CDK6, SOD2, and NF-κB proteins.

Pharmacokinetic studies in rats, supported by GastroPlus modeling, showed that co-administration improved peak concentration and overall exposure of both cannabinoids, likely due to enhanced jejunal absorption. This is the first study to combine in vitro, in vivo, and pharmacokinetic evidence supporting CBC and CBD as a potential strategy against chemotherapy-resistant TNBC.