β-Tocotrienol

β-Tocotrienol is an isomer of vitamin E. β-Tocotrienol is a less potent antioxidant than α-tocotrienol. β-Tocotrienol can be found in the tocotrienol-rich fraction (TRF) of palm oil, which possesses anti-carcinogenic effects in vitro on human colon carcinoma and prostate cancer cells. β-Tocotrienol inhibits the growth of A549 (GI₅₀ = 1.38 μM) and U87MG (GI₅₀ = 2.53 μM) cells. β-Tocotrienol also induces apoptosis in cancer cells. β-Tocotrienol can inhibit PD-L1 expression and mitigates PD-L1-mediated immune suppression in vitro and in vivo^[1][2][3]. In Vitro:β-Tocotrienol (1-100 μM, 24-72 h) significantly inhibits the cell viability in a concentration- and time-dependent manner in both A549 and U87MG cells^[2].
β-Tocotrienol (2 mM for A549; 3 mM for U87MG and 50 mM for MRC5, 72 h) results in well-formed comets and acts to induce apoptosis in both A549 and U87MG cells^[2].
β-Tocotrienol (2-10 μM for A549 and 3-60 μM for U87MG, 24-48 h) increases the ratio of G₀/G₁ phase^[2].
β-Tocotrienol (10 μM) results in loss of membrane integrity, vacuoles formation and cytoplasmic extension in A549 cells^[2].
β-Tocotrienol (10-30 μM) downregulates PD-L1 expression and suppresses PD-L1-mediated tumor-intrinsic signaling in LLC lung cancer and DU145 prostate cancer cells^[3]. In Vivo:β-Tocotrienol (100 mg/kg, p.o., daily for 10 d) inhibits tumor growth in LLC xenograft mouse model^[3].