Abstract 318: Trigonella foenum (fenugreek) inhibited cancer stem cell properties and increased sensitivity to Doxorubicin resistant ZR-75-1 human breast cancer cell line by targeting mutant p53 and Notch-4

Abstract

Abstract Despite advances in detection and therapies, breast cancer is the most common malignant disease in women worldwide. Doxorubicin is one of the effective agent for breast cancer treatment, but the resistance to it is representing a major obstacle for breast cancer treatment. Herein, we established a breast cancer cell line that showed a significant resistance to doxorubicin at clinically relevant concentrations. The epithelial breast cancer cell line ZR-75-1 was sequentially treated with doxorubicin for several treatment cycles. In consequence, we obtained chemoresistant cells displaying a mesenchymal-like phenotype, ZR-75-1-DR. The ZR-75-1-DR cells showed an increase in breast cancer stem cells (BCSC) activity, mutant p53 but not wild type, NOTCH-4 and microRNAs, small noncoding RNAs, expression compared to parental cells, suggesting their expression may contribute to the evolvement of BCSCs. Understanding the early molecular mechanisms of cross talk among mutant p53, Notch-4 and microRNAs in resistant to doxorubicin is crucial to provide better therapeutic strategies for breast cancer progression. Recently, we showed that Trigonella foenum (Fenugreek) extract (FCE), a traditional herbal plant with anti-tumor activity, induced apoptosis in HepG2 cells mediated by up-regulation of wild P53. To investigate the possible effect of FCE in the expression levels of mutant p53, Notch-4 and miRNAs in ZR-75-1-DR and parental cell lines, cells were pre-treated with or without FCE and/or doxorubicin for different time intervals. miRNAs were quantified using qRT-PCR and p53, Notch-4 expression and BCSC phenotype were evaluated by western blot analysis and immunohistochemistry. Our results revealed that FCE treatment showed a significant decrease in cell viability, clonogenicity and invasion capacity with a decrease in expression of mutant p53 and Notch-4 in ZR-75-1-DR compared to untreated cells. Furthermore, the inhibition of mutant p53 and Notch-4 expression was associated with a significant decrease in miR-21 and miR-142 with an increase in expression of let-7a and miR-34a. Furthermore, ZR-75-1-DR pre-treated with FCE showed an increase in chemosensitivity to doxorubicin at low doses with reduction in expression of stemness factor, ALDH1, compared to the parental and doxorubicin treated cells. In vivo, knockdown both mutant p53 and NOTCH-4 showed a significant regression in tumor size of ZR-75-1-DR xenografts compared to those of parental cells and control lentivirus after combined treatment with FCE and doxorubicin, but not with doxorubicin alone. All in all, our data introduced FCE as a promising non-toxic herbal, which has fourteen bioactive compounds and therapeutic potential to reduced cancer stem cell properties and increased sensitivity to doxorubicin treatment, by directly targeting mutant p53, NOTCH4 and microRNAs. Citation Format: Ahmed S. Sultan, Amira S. Fayala, Marwa Elkamel, Reem Bakir, Fatma Foad. Trigonella foenum (fenugreek) inhibited cancer stem cell properties and increased sensitivity to Doxorubicin resistant ZR-75-1 human breast cancer cell line by targeting mutant p53 and Notch-4. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 318.