Novel spiroisatin-pyranopyrazole hybrids as anticancer agents with TrkC inhibitory potential

Cancer still represents a global health concern due to its high mortality and morbidity rates. Isatin-and pyrazole-based compounds have recently garnered interest as novel anticancer agents. A series of 15 novel spiroisatin pyranopyrazole derivatives were synthesized. Anticancer potential of synthesized agents against EBC-1, HT-29, A549, and AsPC-1 cell lines, representing cancers of the lung, colon, and pancreas, were evaluated using the MTT assay. The possible molecular mechanism contributing to antiproliferative activities of the most potent compounds was further investigated <i>in silico</i> by using SuperPred web server, a ligand-based tool. Docking and molecular dynamics (MD) simulation studies were carried out to investigate the binding affinity and key interactions of the agents with their predicted target. Among the tested compounds, four cyanide-containing derivatives <b>6c</b>, <b>6d</b>, <b>6f</b>, and <b>6g</b> with bromobenzyl, chlorobenzyl, p-<i>t</i>Butyl benzyl and methylbenzyl moieties on the isatin ring, respectively, displayed the highest antiproliferative effects against all four cell lines. These compounds were particularly effective against EBC-1, and HT-29 cells with IC₅₀ values of 3.3-7.1 and 7.3-10.2 μΜ, respectively, while relatively sparing non-cancer cells. The obtained target prediction results suggested that the growth inhibitory activity of the analyzed analogues could be related to tropomyosin receptor kinase C (TrkC) inhibition. The outcomes of molecular docking and MD simulation demonstrated that the most active agents may interact closely with the active site of the suggested target, further confirming target prediction findings. The findings of this study suggest the potential of spiroisatin pyranopyrazole analogues for further exploration as novel targeted anticancer agents.