| Whole flaxseed (FS) reduces mammary tumourigenesis, possibly due to its high lignan (secoisolariciresinol diglycoside, SDG) and/or a-linolenic acid (ALA)-rich oil (FSO) content. Sesame seed (SS) is sesamin (SES) lignan-rich and ALA-deficient, but non-protective. Like SDG, SES metabolizes to estrogen-like enterodiol (ED) and enterolactone (EL). This study determined the effects of SES, SDG and FSO on MCF-7 tumourigenesis in athymic mice under high estrogen levels to differentiate whole FS and SS effects. Only SES and FSO reduced palpable tumour size. SES and FSO increased apoptosis, while all treatments reduced proliferation, HER2 and EGFR expressions. FSO reduced Akt expression, while SES and FSO reduced pMAPK. No treatments affected IGF-1R, VEGFR, MAPK or pAkt. Only FSO increased serum ALA, eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). ALA. but not SES, ED or EL, reduced proliferation in vitro . Thus, ALA, EPA and/or DHA of FSO may explain the anti-tumourigenicity of whole FS versus SS. |
