Prodelphinidin B-2,3,3"-O-gallate via chemical oxidation of epigallocatechin-3-gallate shows high efficacy inhibiting triple-negative breast cancer cells.

Abstract

Background: Triple-negative breast cancer is a clinically aggressive malignancy with poorer outcomes versus other subtypes of breast cancer. Numerous reports have discussed the use of epigallocatechin-3-gallate (EGCG) against various types of cancer. However, the effectiveness of EGCG is limited by its high oxidation and instability. The Notch pathway is critical in breast cancer development and prognosis, and its inhibition is a potential treatment strategy.

Results: In this study, we investigated the effects of prodelphinidin B-2,3,3''-O-gallate (named PB2,3,3''/OG or compound 2) via chemical oxidation of EGCG on cell viability and the Notch1 signaling pathway in breast cancer cells. We found that compound 2 showed significant cytotoxicity against triple-negative breast cancer cells, with the half maximal inhibitory concentration (IC₅₀) values ranging 20-50 µM. In MDA-MB453 cells, compound 2 inhibited proliferation, clone formation, and the expression of proteins involved in the Notch1 signaling pathway. Furthermore, compound 2 induced cell cycle arrest and apoptosis. Consistent with the results of in-vitro experiments, treatment with compound 2 significantly reduced tumor growth. Mechanistically, compound 2 directly bound to Notch1 with high binding affinity (dissociation constant: K_D=4.616 × 10^- 6 M).

Conclusion: Our finding suggested that compound 2 may be a promising agent for the development of novel anti-cancer therapy options.