Coumarin-Ferulic Acid Hybrid Mediates HT-29-Selective Growth Inhibition and Proteomic Profiling

Coumarin-based molecular hybrids provide a framework for examining how structural changes influence cellular responses. This study compared four hybrids and three reference compounds across ten human cancer cell lines, with the lead hybrid also tested in non-cancerous Beas-2B cells, followed by functional assays and quantitative expression proteomics in HT-29 cells. Of 70 compound-cell-line combinations, the ferulic ester hybrid (FEC) was the only compound to yield a reproducibly measurable IC₅₀ within the primary screening range, reaching 42.8 ± 4.7 µM in HT-29 cells. Replacing the ferulic moiety or the ester linkage reduced activity within this series. HCT116 cells did not reach 50% inhibition at up to 100 µM. Basal PPARγ abundance did not consistently explain sensitivity across the panel. FEC reduced metabolic activity and colony formation, whereas annexin V/propidium iodide analysis showed a smaller apoptotic response. Proteomics identified coordinated decreases in DNA replication and translation proteins and a modest increase in endoplasmic reticulum protein-folding enzymes. These findings support a structure-dependent and cell-context-dependent antiproliferative response despite moderate potency.