The Mechanisms of Chansu in Inducing Efficient Apoptosis in Colon Cancer Cells

Figure 1

Cytotoxic effects of CBF in human cancer cell lines. (a) Cytotoxicity assays of CBF. A variety of human cancer cell lines were exposed to CBF for 24 hours and exhibited a reduction in cell numbers. The EC₅₀ values were measured by using MTT assays. Results are means with standard errors from 9 replicates. (b) Annexin V/PI analysis by flow cytometry. HCT116 and HT29 cells were treated with 0 or 1 µM CBF for 24 hours and stained with Annexin V/PI dyes. The lower right percentage indicated the apoptotic cells stained with Annexin V and represented a significant increment after exposure to CBF, as well as the proportion of dying cells stained with both dyes (upper right). No elevation in PI stained cells (upper left) was observed and a reduction was in living cell number (lower left) after CBF treatment. (c) The occurrence of mitochondrial permeabilisation in CBF-induced cell death. Untreated and CBF-treated HCT116 and HT29 cells were stained with JC-1 dye, which shows red in living cells and green in dying cells. The fraction (green/red) between treated and untreated cells indicated the change of mitochondrial potential transition. Results are means with standard errors from 3 replicates. (d) Deregulation in cytotoxicity signaling multipathway arrays after CBF treatment. The most significant change is in HIF-1α-regulated pathway, in which HIF-1α level was 2.8 times as low as the untreated cells. On the other hand, the most upregulation occurred in the MAPK/ERK pathway, where the expression of SRF/Elk-1 increased by 2.4 times. The logarithm of untreated cell luciferase intensity was set to baseline. p53, pathway of p53/DNA damage; HIF-1, pathway of hypoxia; NFκB, pathway of NFκB; GR, pathway of glucocorticoid receptor; E2F, pathway of cell cycle/pRb-E2F; SRF/Elk-1, pathway of MAPK/ERK; AP-1, pathway of MAPK/JNK; NFAT, pathway of PKC/Ca²⁺; SMAD2/SMAD3/SMAD4, pathway of TGFβ; and Myc/Max, pathway of Myc/Max. Results are means with standard errors from 4 replicates.