Synthesis and biological evaluation of new steroidal pyridines as potential anti-prostate cancer agents

A series of new steroidal pyridines have been synthesized through the based-promoted three-component reaction and preliminarily evaluated for their antiproliferative activity against different types of cancer cell lines. SARs studies showed that the heterocyclic rings attached to the 4-position of the pyridine ring were preferred over the phenyl rings for the activity. Among these compounds, the most potent compound exhibited good growth inhibition against all the tested cancer cells, especially for PC-3 cells with an IC₅₀ value of 1.55 μM. Further mechanistic studies revealed that the most potent compound inhibited colony formation, migration and evasion of PC-3 cells in a concentration-dependent manner as well as induced apoptosis of PC-3 cells possibly through the mitochondria-related apoptotic pathways. Caspase-3/-9 and PARP were activated, finally leading to the apoptosis of PC-3 cells. For the androgen-sensitive (AR⁺) prostate cancer cell line LNCaP, the most potent compound was less potent than abiraterone with the IC₅₀ value of 8.48 and 3.29 μM, respectively. The most potent compound could be used as a starting point for the development of new steroidal heterocycles with improved anticancer potency and selectivity. The synthesized steroidal pyridines contain the functional -OEt and CN groups, which could be used for further modifications for the construction of the steroid library.