Synthesis and structure-activity relationship studies of parthenolide derivatives as potential anti-triple negative breast cancer agents.

Triple-negative breast cancer (TNBC) is the most aggressive cancers with a high recurrence rate and rapidly acquired drug resistance among various breast cancer subtypes. There is no specific drug for treatment of TNBC. Discovery of therapeutic agents with unique modes of actions is urgently needed. In this study, a series of seventy parthenolide derivatives was designed, synthesized, and evaluated for their anti-TNBC activities. Compound 7d exhibited the most potent activity against different breast cancer cells with IC₅₀ values ranging from 0.20 μM to 0.27 μM, which demonstrated 11.6- to 18.6-fold improvement comparing to that of the parent compound parthenolide with IC₅₀ values of 2.68-4.63 μM. It is worth to note that 7d was more active than the positive control drug ADR. Moreover, compound 7d could induce apoptosis of SUM-159 cells through mitochondria pathway and cause G1 phase arrest of SUM-159 cells. These findings indicate that compound 7d deserves further studies as a lead compound for ultimate discovery of effective anti-TNBC drug.