Crocin Induces Apoptosis in Primary Cancer Epithelial Cells Isolated from Human Breast Tumors via Different Mechanisms in HER2- Negative or Positive Cells: A Preliminary Study

Abstract

Purpose The anticancer effect of Crocin, a natural C20 carotenoid, has been previously demonstrated in different cancer cell lines and animal cancer models. Herein, we investigated its effect on primary breast cancer cells isolated from women’s breast tumor samples. Methods We previously isolated and characterized epithelial breast cancer and normal cells from female patients. In this study, we treated five cancer cells and five normal cells from the same sample with Crocin. Then, the type and mechanisms of Crocin-induced cell death were studied using different techniques. Results All of these tumors were estrogen and progesterone receptor-positive. Two samples were in grade II and HER2-negative, while three others were grade III and HER2-positive. The IC50 of Crocin were obtained using MTT assay for all cells. It induced procaspase-9 expression and cleavage, sub-G1 accumulation, XBP1 mRNA splicing and expression of the spliced XBP1, LC3-II accumulation, and accumulation of unprenylated Rap1α in all cancer cells. The p27 mRNA expression was only induced in cells isolated from HER2-negative samples. However, an increase in the p27 protein level was observed in all cells. Crocin also down-regulated the CXCR-4 and suppressed EpCAM in these cancer cells. The unfarnesylated Lamin B was observed only in one sample. Conclusion Crocin suppressed the proliferation of human primary epithelial breast cancer cells, enhanced stress responses, and decreased metastatic markers. There was a difference between p27 expression in HER2-negative and positive tumors.