Comparative analysis of cell death induction by Taurolidine in different malignant human cancer cell lines

Abstract

Background: Taurolidine (TRD) represents an anti-infective substance with anti-neoplastic activity in many malignant cell lines. So far, the knowledge about the cell death inducing mechanisms and pathways activated by TRD is limited. The aim of this study was therefore, to perform a comparative analysis of cell death induction by TRD simultaneously in different malignant cell lines.

Materials and methods: Five different malignant cell lines (HT29/Colon, Chang Liver/Liver, HT1080/fibrosarcoma, AsPC-1/pancreas and BxPC-3/pancreas) were incubated with increasing concentrations of TRD (100 microM, 250 microM and 1000 microM) for 6 h and 24 h. Cell viability, apoptosis and necrosis were analyzed by FACS analysis (Propidiumiodide/AnnexinV staining). Additionally, cells were co-incubated with the caspase Inhibitor z-VAD, the radical scavenger N-Acetylcystein (NAC) and the Gluthation depleting agent BSO to examine the contribution of caspase activation and reactive oxygen species in TRD induced cell death.

Results: All cell lines were susceptible to TRD induced cell death without resistance toward this anti-neoplastic agent. However, the dose response effects were varying largely between different cell lines. The effect of NAC and BSO co-treatment were highly different among cell lines--suggesting a cell line specific involvement of ROS in TRD induced cell death. Furthermore, impact of z-VAD mediated inhibition of caspases was differing strongly among the cell lines.

Conclusion: This is the first study providing a simultaneous evaluation of the anti-neoplastic action of TRD across several malignant cell lines. The involvement of ROS and caspase activation was highly variable among the five cell lines, although all were susceptible to TRD induced cell death. Our results indicate, that TRD is likely to provide multifaceted cell death mechanisms leading to a cell line specific diversity.

Figure 1

Effects of Taurolidine on viability, apoptosis and necrosis in HT29, Chang Liver and HT1080 cells. HT29 (a-c), Chang Liver (d-f) and HT1080 cells (g-i) were incubated with Taurolidine (TRD) (100 μM, 250 μM and 1000 μM) and with Povidon 5% (control) for 24 h. The percentages of viable (a, d, g), apoptotic (b, e, h) and necrotic cells (c, f, i) were determined by FACS-analysis for Annexin V-FITC and Propidiumiodide. Values are means ± SEM of 5 (HT29), 4 (Chang Liver) and 9 (HT1080) independent experiments with consecutive passages. Asterisk symbols on columns indicate differences between control and TRD treatment. Asterisk symbols on brackets indicate differences between TRD groups. *** p ≤ 0.001, ** p ≤ 0.01, * p ≤ 0.05 (one-way ANOVA).

Figure 2

Effects of Taurolidine on viability, apoptosis and necrosis in AsPC-1 and BxPC-3 cells. AsPC-1 (a-c) and BxPC-3 cells (d-f) were incubated with Taurolidine (TRD) (100 μM, 250 μM and 1000 μM) and with Povidon 5% (control) for 24 h. The percentages of viable (a, d), apoptotic (b, d) and necrotic cells (c, f) were determined by FACS-analysis for Annexin V-FITC and Propidiumiodide. Values are means ± SEM of 4 independent experiments with consecutive passages. Asterisk symbols on columns indicate differences between control and TRD treatment. Asterisk symbols on brackets indicate differences between TRD groups. *** p ≤ 0.001, ** p ≤ 0.01, * p ≤ 0.05 (one-way ANOVA).

Figure 3

Representative dot plots obtained by FACS-anaylsis after incubation of different cell lines with Taurolidine. Chang Liver, HT1080 and BxPC-3 cells were incubated with Taurolidine (TRD) (100 μM, 250 μM and 1000 μM) and with Povidon 5% (control) for 24 h. FACS-analysis was performed for Annexin V-FITC (x-axis) and Propidiumiodide (y-axis). Lower left quadrant: Annexin V and propidium iodide negative (viable), lower right quadrant: Annexin V positive and propidium iodide negative (apoptotic), upper right quadrant: Annexin V and propidium iodide positive (necrotic).

Figure 4

Effects of N-acetylcysteine on Taurolidine induced cell death in HT29, Chang Liver and HT1080 cells. HT29 (a-c), Chang Liver (d-f) and HT1080 cells (g-i) were incubated with either the radical scavenger N-acetylcysteine (NAC) (5 mM), Taurolidine (TRD) (250 μM) or the combination of both agents (TRD 250 μM + NAC 5 mM) and with Povidon 5% (control) for 24 h. The percentages of viable (a, d, g), apoptotic (b, e, h) and necrotic cells (c, f, i) were determined by FACS-analysis for Annexin V-FITC and Propidiumiodide. Values are means ± SEM of 4 (HT29 and Chang Liver) and 12 (HT1080) independent experiments with consecutive passages. Asterisk symbols on brackets indicate differences between treatment groups. *** p ≤ 0.001, ** p ≤ 0.01, * p ≤ 0.05 (one-way ANOVA).

Figure 5

Effects of DL-buthionin-(S,R)-sulfoximine on Taurolidine induced cell death in HT29, Chang Liver and HT1080 cells. HT29 (a-c), Chang Liver (d-f) and HT1080 cells (g-i) were incubated with either the glutathione depleting agent DL-buthionin-(S,R)-sulfoximine(BSO) (1 mM), Taurolidine (TRD) (250 μM) or the combination of both agents (TRD 250 μM + BSO 1 mM) and with Povidon 5% (control) for 24 h. The percentages of viable (a, d, g), apoptotic (b, e, h) and necrotic cells (c, f, i) were determined by FACS-analysis for Annexin V-FITC and Propidiumiodide. Values are means ± SEM of 9 (HT29 and HT1080) and 4 (Chang Liver) independent experiments with consecutive passages. Asterisk symbols on brackets indicate differences between treatment groups. *** p ≤ 0.001, ** p ≤ 0.01, * p ≤ 0.05 (one-way ANOVA).

Figure 6

Effects of N-acetylcysteine on Taurolidine induced cell death in AsPC-1 and BxPC-3 cells. AsPC-1 (a-c) and BxPC-3 cells (d-f) were incubated with either the radical scavenger N-acetylcysteine (NAC) (5 mM), Taurolidine (TRD) (250 μM for BxPC-3 and 1000 μM for AsPC-1) or the combination of both agents (TRD 250 μM/1000 μM + NAC 5 mM) and with Povidon 5% (control) for 24 h. The percentages of viable (a, d), apoptotic (b, e) and necrotic cells (c, f) were determined by FACS-analysis for Annexin V-FITC and Propidiumiodide. Values are means ± SEM of 4 independent experiments with consecutive passages. Asterisk symbols on brackets indicate differences between treatment groups. *** p ≤ 0.001, ** p ≤ 0.01, * p ≤ 0.05 (one-way ANOVA).

Figure 7

Effects of DL-buthionin-(S,R)-sulfoximine on Taurolidine induced cell death in AsPC-1 and BxPC-3 cells. AsPC-1 (a-c) and BxPC-3 cells (d-f) were incubated with either the glutathione depleting agent DL-buthionin-(S,R)-sulfoximine(BSO) (1 mM), Taurolidine (TRD) (250 μM for BxPC-3 and 1000 μM for AsPC-1) or the combination of both agents (TRD 250 μM/1000 μM + BSO 1 mM) and with Povidon 5% (control) for 24 h. The percentages of viable (a, d), apoptotic (b, e) and necrotic cells (c, f) were determined by FACS-analysis for Annexin V-FITC and Propidiumiodide. Values are means ± SEM of 4 independent experiments with consecutive passages. Asterisk symbols on brackets indicate differences between treatment groups. *** p ≤ 0.001, ** p ≤ 0.01, * p ≤ 0.05 (one-way ANOVA).

Figure 8

Effects of caspase-inhibition on Taurolidine induced cell death in HT29, Chang Liver and HT1080 cells. HT29 (a-c), Chang Liver (d-f) and HT1080 cells (g-i) were incubated with either z-VAD.fmk (1 μM), Taurolidine (TRD) (250 μM) or the combination of both agents (TRD 250 μM + zVAD.fmk 1 μM) and with Povidon 5% (control) for 24 h. The percentages of viable (a, d, g), apoptotic (b, e, h) and necrotic cells (c, f, i) were determined by FACS-analysis for Annexin V-FITC and Propidiumiodide. Values are means ± SEM of 5 (HT29), 6 (Chang Liver) and 4 (HT1080) independent experiments with consecutive passages. Asterisk symbols on brackets indicate differences between treatment groups. *** p ≤ 0.001, ** p ≤ 0.01, * p ≤ 0.05 (one-way ANOVA).

Figure 9

Effects of caspase-inhibition on Taurolidine induced cell death in AsPC-1 and BxPC-3 cells. AsPC-1 (a-c) and BxPC-3 cells (d-f) were incubated with either z-VAD.fmk (1 μM), Taurolidine (TRD) (250 μM for BxPC-3 and 1000 μM for AsPC-1) or the combination of both agents (TRD 250 μM/1000 μM + zVAD.fmk 1 μM) and with Povidon 5% (control) for 24 h. The percentages of viable (a, d), apoptotic (b, e) and necrotic cells (c, f) were determined by FACS-analysis for Annexin V-FITC and Propidiumiodide. Values are means ± SEM of 3 (AsPC-1) and 6 (BxPC-3) independent experiments with consecutive passages. Asterisk symbols on brackets indicate differences between treatment groups. *** p ≤ 0.001, ** p ≤ 0.01, * p ≤ 0.05 (one-way ANOVA).