Figure 2

A suboptimal dose of ceramide analog LCL85 overcomes metastatic human colon carcinoma cell resistance to Fas-mediated apoptosis. A & B. Sensitization of primary (A) and metastatic (B) human colon carcinoma cells to FasL-induced growth inhibition by LCL85. Six primary human colon carcinoma cell lines (A) and 5 metastatic human colon carcinoma cell lines (B) were cultured in the absence or presence of a sublethal dose of LCL85 (5 μM) and FasL at the indicated concentrations for 24 h. Cell growth rate was measured by MTT assays. *p < 0.05; **p < 0.01. C & D. SW620 (C) and LS411N (D) cells were incubated with LCL85 at the indicated dose for 1 h and then cultured in the absence or presence of FasL (250 ng/ml) overnight. Cells were stained with Annexin V and PI and analyzed by flow cytometry. Cell death is indicated at the top right corner of each plot. Percentage of FasL-induced cell death is calculated by the formula: % Annexin V⁺ and PI⁺ cells in the presence of FasL- % Annexin V⁺ and PI⁺ cells in the absence of FasL, and presented at the right.