Synthesis and antitumor evaluation of novel hybrids of phenylsulfonylfuroxan and epiandrosterone/dehydroepiandrosterone derivatives.

Abstract Thirteen novel furoxan-based nitric oxide (NO) releasing hybrids ( 14a–e , 15a–e , 17b–d ) of 16,17-pyrazo-annulated steroidal derivatives were synthesized and evaluated against the MDA-MB-231, HCC1806, SKOV-3, DU145, and HUVEC cell lines for their in vitro anti-proliferative activity. Most of the compounds displayed potent anti-proliferative effects. Among them, 17c exhibited the best activity with IC 50 values of 20–1.4 nM against four cell lines (MDA-MB-231, SKOV-3, DU145, and HUVEC), and 1.03 μM against a tamoxifen resistant breast cancer cell line (HCC1806). Furthermore, five compounds ( 14a , 15a , 17b–d ) were selected to screen for VEGF inhibitory activity. Compounds 15a , 17b , c showed obviously better activity than 2-Methoxyestradiol (2-ME) on reducing levels of VEGF secreted by MDA-MB-231 cell line. In a Capillary-like Tube Formation Assay, compounds 17b , c exhibited a significant suppression of the tubule formation in the concentration of 1.75 nM and 58 nM, respectively. The preliminary SAR showed that steroidal scaffolds with a linker in 3-position were favorable moieties to evidently increase the bioactivities of these hybrids. Overall, these results implied that 17c merited to be further investigated as a promising anti-cancer candidate.