Growth of Breast Cancer Cells Inhibited by Bromelains Extracted from the Different Tissues of Pineapple

Abstract

Breast cancer is a common disease diagnosed in women. The therapies for breast cancer often have side effects and the most effective drugs are highly toxic. Finding safe alternative medicines is an important goal in the search for a cure for breast cancer. Bromelains are a mixture of cysteine proteases extracted from pineapple. Pineapple is considered to be a safe food. In this paper, the breast cancer cell lines MCF7 and MDA-MB-231 were co-cultured with bromelains extracted from different tissues of the pinapple. Results showed that the growth of MCF7 and MDA-MB-231 cells can be inhibited by bromelains. The bromelains for this study were extracted from the fruit pulp, peel, fruit stalk, young stem, and mature stem. Bromelains extracted from the fruit stalk were found to be the most effective for inhibiting the growth of breast cancer cells. MCF7 was more sensitive to bromelains than MDA-MB-231. After the breast cancer cells were co-cultured with the bromelain, the transcripts of p53 and Bax increased significantly. The transcriptional expressions of Cox-2 and Bcl-2 were down-regulated. More proteins of p53 and Bax were produced. The translational expressions of Cox-2 and Bcl-2 were both down-regulated. Bromelains inhibited the growth of BC cells through the up-regulating of p53, Bax, and by decreasing the expressions of Cox-2 and Bcl-2. The activity of nuclear factor-kappa B (NF-κB) might be blocked. Final effects might be performed by regulating the functions of the protein kinase.