A bioimaging system combining human cultured reporter cells and planar chromatography to identify novel bioactive molecules

Highlights: • First on-surface adherent cell assays were demonstrated. • Adherent human cells grow on planar chromatogram with separated samples. • Human cells used as a biodetector for cytotoxic substances on HPTLC plates. • Non-target screening of cytotoxic substances in natural samples. • Activation of the PPARy receptor in human adherent cells on HPTLC plates. For the first time, a human cancer cell line was shown to grow and be functionally active on the particulate porous adsorbent surface of separated sample mixtures. This allowed the novel combination of chromatographic separations with human cells as biological detector. As exemplary screening for cancer treatment drugs, cytotoxic substances were directly discovered in Saussurea costus and ginseng samples using the Cytotox CALUX® osteosarcoma cells (with luciferase expressing reporter gene) as detector. In addition, rosiglitazone and pioglitazone were detected as luminescent zones upon binding to the PPARγ receptor expressed in the respective CALUX cell line that was grown on the surface of the adsorbent. This demonstrates the ability to address receptor-mediated signaling with this method, and opens the perspective to use our novel bioimaging method to identify bioactive molecules targeting a wide range of pathways with toxicological, pharmaceutical and nutraceutical relevance. The new bioimaging directly pointed to individual effective compounds in multi-component mixtures. Furthermore, discovered effective compounds were directly characterized by online elution to high-resolution mass spectrometry and fragmentation.