(A) GS induces activation of caspases 8/9/3. Quantitative fluorogenic assay for caspase activation was carried out as described in materials and methods. Treatment with GS (50 μM) induced significant increase in activation of caspases 8/9/3 (*, ** p < 0.05) in 6 h - 12 h as compared to vehicle control. (B) Western blot analysis showing (i) cleaved caspase 9; (ii) cleaved caspase 8; (iii) cleaved caspase 3; and (iv) cleaved PARP confirmed caspase-dependent apoptosis; (iv) α-tubulin served as loading control. (C) GS induced the expression of CD95/Fas. Panel shows % SCC4 cells expressing CD95/Fas receptor on treatment with GS (50 μM) (i) 0 h; (ii) 6 h; (iii) 12 h; (iv) 24 h; (v) 36 h using flow cytometry.