MATERIALS AND METHODS: Anti-cancer activity of a tocotrienol-rich fraction (TRF) and a tocotrienol-enriched fraction (TEF) isolated from palm oil, as well as pure vitamin E analogues (α-tocopherol, α-, δ- and γ-tocotrienols) were studied using highly aggressive triple negative MDA-MB-231 cells and oestrogen-dependent MCF-7 cells, both of human breast cancer cell lines. Cell population growth was evaluated using a Coulter particle counter. Cell death mechanism, poly(ADP-ribose) polymerase cleavage and levels of NF-κB were determined using commercial ELISA kits.
RESULTS: Tocotrienols exerted potent anti-proliferative effects on both types of cell by inducing apoptosis, the underlying mechanism of cell death being ascertained using respective IC50 concentrations of all test compounds. There was marked induction of apoptosis in both cell lines by tocotrienols compared to treatment with Paclitaxel, which was used as positive control. This activity was found to be associated with cleavage of poly(ADP-ribose) polymerase (a DNA repair protein), demonstrating involvement of the apoptotic cell death signalling pathway. Tocotrienols also inhibited expression of nuclear factor kappa-B (NF-κB), which in turn can increase sensitivity of cancer cells to apoptosis.
CONCLUSION: Tocotrienols induced anti-proliferative and apoptotic effects in association with DNA fragmentation, poly(ADP-ribose) polymerase cleavage and NF-κB inhibition in the two human breast cancer cell lines.
AIM OF THE STUDY: To investigate the potential of F3 from S. crispus to prevent metastasis in breast cancer.
MATERIALS AND METHODS: The antimetastatic effects of F3 were first investigated on murine 4T1 and human MDA-MB-231 breast cancer cell (BCC) lines using cell proliferation, wound healing and invasion assays. A 4T1-induced mouse mammary carcinoma model was then used to determine the expression of metastasis tumor markers, epithelial (E)-cadherin, matrix metalloproteinase (MMP)-9, mucin (MUC)-1, nonepithelial (N)-cadherin, Twist, vascular endothelial growth factor (VEGF) and vimentin, using immunohistochemistry, following oral treatment with F3 for 30 days.
RESULTS: Significant growth arrest was observed with F3 IC50 values of 84.27 µg/ml (24 h) and 74.41 µg/ml (48 h) for MDA-MB-231, and 87.35 µg/ml (24 h) and 78.75 µg/ml (48 h) for 4T1 cells. F3 significantly inhibited migration of both BCC lines at 50 μg/ml for 24 h (p = 0.018 and p = 0.015, respectively). Similarly, significant inhibition of invasion was demonstrated in 4T1 (75 µg/ml, p = 0.016) and MDA-MB-231 (50 µg/ml, p = 0.040) cells compared to the untreated cultures. F3 treatment resulted in reduced tumor growth compared to untreated mice (p