Fig. 1

TCPT induces cell death of SCLC. A cell viability of various lung cancer cell lines and normal bronchial epithelium lung cell lines BEAS-2B (black label) after treating TCPT in 24 h. B Inhibition rate of 48 h-treatment of TCPT with different concentration among above cell lines. The deeper the Block color, the higher the inhibition rate of TCPT treatment. C Colony formation results of H1688 cells when treating TCPT. Left panel indicates the colony numbers under each concentration of TCPT, right panel displays the count numbers with statistic analysis. D FCM detects cell viability and death in H1688 cells when treating with series concentration of TCPT in 24 h. Bar chart in right panel shows percentage of cell in specific quadrant. Lower right quadrant presents single positive of FITC-Annexin-V staining, which is a classical feature of early apoptosis, thereby presenting in bar chart as early apoptosis. Upper left quadrant (single positive PI staining) and upper right quadrant (double positive FITC-Annexin-V/PI) presents late apoptosis cells, since the ferroptosis, pyroptosis, programmed necrosis or other death type shares the similar feature as late apoptosis. E observation of cellular ultrastructure with TEM among H1688 with TCPT treatment and its blank counterpart. White arrows indicate mitochondria, pink arrows indicate endoplasmic reticulum, yellow arrows indicate lysosomes and blue arrowhead indicate vesicas encapsulated other organelles. F staining of mitochondria using Mito-Tracker probe. Decreased amount of intracellular dye indicates the attenuation of mitochondrial membrane potential. Bar chart presents the semi-quantitative analysis of mitochondrial staining. G protein expression of cytochrome C, caspase 3 and claved-caspase 3 among H1688 with different TCPT treatment and its blank counterpart. *, ** vs blank group, present P value < 0.05 and 0.01 respectively