Acetyl Glycyrrhetinic Acid Methyl Ester as a Promising Glycyrrhizin Derivative against the Breast Cancer Cells (MCF-7)

Background: Breast cancer remains the most potent threat to women’s life worldwide. So far, no ideal drug for treatment of breast cancer, all available drugs exhibit severe side effects, poor therapeutic index, and high cost. 
Objective: Therefore, this study aimed to investigate the potential use of the natural pentacyclic triterpenoids such as Boswellic, Betulinic (BA), Urosolic, Oleanolic acids, Glycyrrhizin and their derivatives for treatment of breast cancer. 
Materials and methods: The cell viability was firstly determined after treatment with 50 μM of each compound. The effect of the treatment on cell cycle, apoptosis, cell migration and colony formation was evaluated. The ability of the new glycyrrhizin derivative to activate p53 was investigated by flow cytometry. 
Results: The cytotoxicity assay revealed that glycyrrhizin derivative AM-GA (3-acetyl-18β-glycyrrhetinic-30-methyl ester) and BA were the most cytotoxic against breast cancer cell line MCF-7 with IC50 values 4.5±0.1 and 4±0.1 μM, respectively. Both AM-GA and BA were selective towards breast cancer cells rather than the normal lung fibroblast cell line WI-38. Both AM-GA and BA were able to inhibit the cancer cell migration in the wound healing assay and inhibited colony formation. Studying the mechanism of action revealed that AM-GA inhibited the growth of the breast cancer cells via cell cycle arrest at sub-G1 phase, induction of apoptosis and activation of the tumor suppressor protein p53. 
Conclusion: This work highlights the unique role of AM-GA against breast cancer via different mechanisms and will be the gate for new potent analogues and fights different cancer types.