The design, synthesis and anti-tumor mechanism study of new androgen receptor degrader.

Targeted protein degradation using small molecules is a novel strategy for drug development. In order to solve the problem of drug resistance in the treatment of prostate cancer, proteolysis-targeting chimeras (PROTAC) was introduced into the design of anti-prostate cancer derivatives. In this work, we synthesized two series of selective androgen receptor degraders (SARDs) containing the hydrophobic degrons with different linker, and then investigated the structure-activity relationships of these hybrid compounds. Most of the synthesized compounds exhibited moderate to good activity against all the cancer cell lines selected. Among them, compound A9 displayed potent inhibitory activity against LNCaP prostate cancer cell line with IC50 values of 1.75 µM, as well as excellent AR degradation activity. Primary mechanism studies elucidated compound A9 arrested cell cycle at G0/G1 phase and induced a mild apoptotic response in LNCaP cells. Further study indicated that the degradation of AR was mediated through proteasome-mediated process. For all these reasons, compound A9 held promising potential as anti-proliferative agent for the development of highly efficient SARDs for drug-resistance prostate cancer therapies.

Synthesis and in vitro biological evaluation of novel derivatives of Flexicaulin A condensation with amino acid trifluoroacetate.

As our research focus on anticancer drugs, two series of novel derivatives of Flexicaulin A (FA), an ent-kaurene diterpene, condensation with amino acid trifluoroacetate were synthesized, and their anti-proliferative activity against four human cancer cell lines (TE-1, MCF-7, A549 and MGC-803) were evaluated. Compared with FA, the anticancer activity and solubility of most derivatives were significantly improved. Among them, compound 6d had the best activity, and its IC50 value against Esophageal cancer cells (TE-1) was up to 0.75 µM. Subsequent cellular mechanism studies showed that compound 6d could inhibit the proliferation of cancer cells, the formation of cell colonies, and increase the level of ROS on TE-1 cells. In addition, 6d could up-regulate the expressions of SAPK/JNK pathway-associated proteins (p-ASK1, p-MKK4 and p-JNK) and pro-apoptotic proteins (Bak, Bad and Noxa), remarkably increase the ratio of Bax to Bcl-2 and activate Cleaved Caspase-3/9/PARP. These results indicate that compound 6d induces apoptosis through the ROS/JNK/Bcl-2 pathway and holds promising potential as an anti-proliferative agent.