Synergistic Anticancer Activity of Cannabinoids and Terpenes Against Triple-Negative Breast Cancer Resistance

Triple-negative breast cancer (TNBC) remains highly aggressive and refractory to conventional treatments, underscoring the need for novel combination strategies. Here, we employed 2D and 3D in vitro models, transcriptomic profiling, and in vivo xenograft studies to evaluate the anticancer efficacy of cannabinoids combined with the terpene β-caryophyllene (BC) in resistant TNBC models. Among the tested cannabinoids, cannabichromene (CBC) exhibited the greatest potency, and its combination with BC at sub-toxic concentrations significantly reduced IC₅₀ values, enhanced cytotoxicity in spheroids, and suppressed colony formation and migration. The combination treatment induced pronounced G1 cell cycle arrest and increased apoptotic cell death. Western blot analyses revealed downregulation of PARP, Survivin, mTOR, Vimentin, Glypican-5, and PD-L1, while RNA sequencing demonstrated suppression of proliferative and migratory signaling pathways alongside activation of apoptosis, autophagy, and ferroptosis-related pathways. In vivo, CBC + BC significantly inhibited tumor growth in MDA-MB-231 xenografts, outperforming single-agent treatments. Collectively, these findings demonstrate that BC synergistically enhances cannabinoid activity, yielding superior antiproliferative and anti-migratory effects, and highlight this combination as a promising therapeutic strategy for resistant TNBC.