Abstract:
Breast cancer is the most prevalent malignancy in females worldwide, with the incidence rate being highest in developed countries. It has been widely accepted that lifestyles such as smoking, physical activity and dietary patterns contribute to the high breast cancer incidence in these countries, where dairy products constitute a major proportion of dietary intake. Given that the hydrolysis of casein, a major milk protein, yields peptides that have important biological functions in the body, their effect on breast cancer needs to be explored. Therefore, the aim of this thesis was to investigate the relationship between bovine casein hydrolysates and breast cancer. A panel of 125 previously described bovine casein-derived peptides were chemically synthesized and 58 of these peptides were screened in this project. In vitro cell-based functional assays were carried out to examine the impact of the peptides on cell growth, anchorage-independent growth in soft agar, and cell migration and invasion of MCF-7 mammary carcinoma cells. Our results demonstrate that 14 of the peptides screened exhibited a potential effect on MCF-7 cells in terms of cell viability or anchorage-independent growth. Of the 14 peptides, five inhibited cell viability in the alamarBlue® assays and seven inhibited anchorage-independent cell growth in soft agar, while two had stimulatory effects from these assays. One prominent peptide BP060 (YPFPGPIHNSL) induced a 33% decrease in cell viability. Overall, our study has demonstrated that casein-derived peptides have potential impacts on the oncogenicity of mammary carcinoma cells. The present findings support the role of bioactive components derived from functional food ingredients, however their benefits and harms at the systemic level is unknown and thus careful considerations should be applied and more experimental investigation is required before any changes in dietary intake are suggested.