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IGF-I activates caspases 3/7, 8 and 9 but does not induce cell death in colorectal cancer cells.

Yang SY, Bolvin C, Sales KM, Fuller B, Seifalian AM, Winslet MC - BMC Cancer (2009)

Bottom Line: The results show that exogenous IGF-I significantly increases activity of caspases 3/7, 8 and 9 in all cell lines used; blocking IGF-I receptor reduce IGF-I-induced caspase activation.Further studies demonstrate that IGF-I induced caspase activation does not result in cell death.The study suggests that caspase activation is not synonymous with apoptosis and that activation of caspases may not necessarily induce cell death.

View Article: PubMed Central - HTML - PubMed

Affiliation: University College London, Division of Surgery and Interventional Science, Royal Free & University College Medical School, Rowland Hill Street, London, UK. shiyu.yang@medsch.ucl.ac.uk

ABSTRACT

Background: Colorectal cancer is the third most common cancer in the western world. Chemotherapy is often ineffective to treat the advanced colorectal cancers due to the chemo-resistance. A major contributor to chemo-resistance is tumour-derived inhibition or avoidance of apoptosis. Insulin-like growth factor I (IGF-I) has been known to play a prominent role in colorectal cancer development and progression. The role of IGF-I in cancer cell apoptosis is not completely understood.

Methods: Using three colorectal cancer cell lines and one muscle cell line, associations between IGF-I and activities of caspase 3/7, 8 and 9 have been examined; the role of insulin-like growth factor I receptor (IGF-IR) in the caspase activation has been investigated.

Results: The results show that exogenous IGF-I significantly increases activity of caspases 3/7, 8 and 9 in all cell lines used; blocking IGF-I receptor reduce IGF-I-induced caspase activation. Further studies demonstrate that IGF-I induced caspase activation does not result in cell death. This is the first report to show that while IGF-I activates caspases 3/7, 8 and 9 it does not cause colorectal cancer cell death.

Conclusion: The study suggests that caspase activation is not synonymous with apoptosis and that activation of caspases may not necessarily induce cell death.

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Related in: MedlinePlus

IGF-I -induced caspases activation is neutralised by anti-IGF-IR antibody  IGF-I-induced activation of caspases 3/7 (a, b), 8 (c, d) and 9 (e, f) in HT-29 cells and caspase 3/7 in SW620 cells (g, h) is neutralised by anti-IGF type 1 receptor antibody (IGF-IR ab). Cells were pre-incubated with (+) or without (-) IGF-IR ab (400 ng/ml) for 30 minutes and then treated with (+) or without (-) IGF-I (50 ng/ml) for 48 hours. The cellular caspase 3/7, 8 and 9 activities were analysed with Caspase-Glo assay kit (Promega, Madison USA). To check whether any IGF-IR antibody neutralization of IGF-I action is a specific effect a general mouse IgG was included (i, j). For mouse IgG control experiment cells were pre-incubated with (+) or without (-) mouse IgG (400 ng/ml) for 30 minutes. The caspase 3/7 activity was analysed with the same method as IGF-IR ab. Significance value: * P <0.05; ** P <0.01. SCM-serum containing media; SFM-serum free media.
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Figure 3: IGF-I -induced caspases activation is neutralised by anti-IGF-IR antibody IGF-I-induced activation of caspases 3/7 (a, b), 8 (c, d) and 9 (e, f) in HT-29 cells and caspase 3/7 in SW620 cells (g, h) is neutralised by anti-IGF type 1 receptor antibody (IGF-IR ab). Cells were pre-incubated with (+) or without (-) IGF-IR ab (400 ng/ml) for 30 minutes and then treated with (+) or without (-) IGF-I (50 ng/ml) for 48 hours. The cellular caspase 3/7, 8 and 9 activities were analysed with Caspase-Glo assay kit (Promega, Madison USA). To check whether any IGF-IR antibody neutralization of IGF-I action is a specific effect a general mouse IgG was included (i, j). For mouse IgG control experiment cells were pre-incubated with (+) or without (-) mouse IgG (400 ng/ml) for 30 minutes. The caspase 3/7 activity was analysed with the same method as IGF-IR ab. Significance value: * P <0.05; ** P <0.01. SCM-serum containing media; SFM-serum free media.

Mentions: To elucidate whether IGF-I activation of caspases 3/7, 8 and 9 is due to the interaction between IGF-I and its receptors, a neutralised anti-IGF type 1 receptor antibody (IGF-IR ab) was used to interfere with the binding of IGF-I to its receptors in cells. The results show that after 48 hours of IGF-I treatment the activity of caspases 3/7, 8 and 9 in HT-29 cells significantly increased in both SCM (figure 3a, c and 3e) and SFM (figure 3b, d and 3f) mediums. When IGF-IR ab was included in the IGF-I treated cells, the caspase 3/7 activities significantly decreased (P < 0.05) in both SCM (figure 3a) and SFM (figure 3b) mediums compared to IGF-I treated groups, while the caspase 8 and 9 activities significantly decreased (P < 0.01) in both SCM (figure 3c and 3e) and SFM (figure 3d and 3f). All these data show that the caspase 3/7, 8 and 9 activation by IGF-I can be inhibited by interfering in the binding between IGF-I and its receptors and indicate that IGF-I activates caspases 3/7, 8 and 9 in HT-29 cells via interaction between IGF-I and its receptors. In SCM medium (figure 3a, c and 3e) IGF-IR ab did not affect caspase 3/7, 8 or 9 activity if the medium did not include exogenous IGF-I compared to untreated groups. However, in SFM medium the caspase 8 (figure 3d) and 9 (figure 3f) activities tend to be lower in IGF-IR ab treated group compared to untreated groups, although these differences did not reach a statistically significant level. The same effect of blocking the IGF-I receptor with IGF-I R ab was also shown in SW620 cells (figure 3g and 3h). When IGF-IR ab was included in SW620 cells, the caspase 3/7 activities significantly decreased (P < 0.01) in both SCM (figure 3g) and SFM (figure 3h) media compared to IGF-I treated groups. In order to check whether IGF-IR antibody neutralization of IGF-I action is a specific effect; a general mouse IgG was included in the experiment. The results (figure 3i and 3j) showed that general mouse IgG was not able to inhibit IGF-I induced caspase activation. This indicates that IGF-IR antibody effect is a specific action.


IGF-I activates caspases 3/7, 8 and 9 but does not induce cell death in colorectal cancer cells.

Yang SY, Bolvin C, Sales KM, Fuller B, Seifalian AM, Winslet MC - BMC Cancer (2009)

IGF-I -induced caspases activation is neutralised by anti-IGF-IR antibody  IGF-I-induced activation of caspases 3/7 (a, b), 8 (c, d) and 9 (e, f) in HT-29 cells and caspase 3/7 in SW620 cells (g, h) is neutralised by anti-IGF type 1 receptor antibody (IGF-IR ab). Cells were pre-incubated with (+) or without (-) IGF-IR ab (400 ng/ml) for 30 minutes and then treated with (+) or without (-) IGF-I (50 ng/ml) for 48 hours. The cellular caspase 3/7, 8 and 9 activities were analysed with Caspase-Glo assay kit (Promega, Madison USA). To check whether any IGF-IR antibody neutralization of IGF-I action is a specific effect a general mouse IgG was included (i, j). For mouse IgG control experiment cells were pre-incubated with (+) or without (-) mouse IgG (400 ng/ml) for 30 minutes. The caspase 3/7 activity was analysed with the same method as IGF-IR ab. Significance value: * P <0.05; ** P <0.01. SCM-serum containing media; SFM-serum free media.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
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Figure 3: IGF-I -induced caspases activation is neutralised by anti-IGF-IR antibody IGF-I-induced activation of caspases 3/7 (a, b), 8 (c, d) and 9 (e, f) in HT-29 cells and caspase 3/7 in SW620 cells (g, h) is neutralised by anti-IGF type 1 receptor antibody (IGF-IR ab). Cells were pre-incubated with (+) or without (-) IGF-IR ab (400 ng/ml) for 30 minutes and then treated with (+) or without (-) IGF-I (50 ng/ml) for 48 hours. The cellular caspase 3/7, 8 and 9 activities were analysed with Caspase-Glo assay kit (Promega, Madison USA). To check whether any IGF-IR antibody neutralization of IGF-I action is a specific effect a general mouse IgG was included (i, j). For mouse IgG control experiment cells were pre-incubated with (+) or without (-) mouse IgG (400 ng/ml) for 30 minutes. The caspase 3/7 activity was analysed with the same method as IGF-IR ab. Significance value: * P <0.05; ** P <0.01. SCM-serum containing media; SFM-serum free media.
Mentions: To elucidate whether IGF-I activation of caspases 3/7, 8 and 9 is due to the interaction between IGF-I and its receptors, a neutralised anti-IGF type 1 receptor antibody (IGF-IR ab) was used to interfere with the binding of IGF-I to its receptors in cells. The results show that after 48 hours of IGF-I treatment the activity of caspases 3/7, 8 and 9 in HT-29 cells significantly increased in both SCM (figure 3a, c and 3e) and SFM (figure 3b, d and 3f) mediums. When IGF-IR ab was included in the IGF-I treated cells, the caspase 3/7 activities significantly decreased (P < 0.05) in both SCM (figure 3a) and SFM (figure 3b) mediums compared to IGF-I treated groups, while the caspase 8 and 9 activities significantly decreased (P < 0.01) in both SCM (figure 3c and 3e) and SFM (figure 3d and 3f). All these data show that the caspase 3/7, 8 and 9 activation by IGF-I can be inhibited by interfering in the binding between IGF-I and its receptors and indicate that IGF-I activates caspases 3/7, 8 and 9 in HT-29 cells via interaction between IGF-I and its receptors. In SCM medium (figure 3a, c and 3e) IGF-IR ab did not affect caspase 3/7, 8 or 9 activity if the medium did not include exogenous IGF-I compared to untreated groups. However, in SFM medium the caspase 8 (figure 3d) and 9 (figure 3f) activities tend to be lower in IGF-IR ab treated group compared to untreated groups, although these differences did not reach a statistically significant level. The same effect of blocking the IGF-I receptor with IGF-I R ab was also shown in SW620 cells (figure 3g and 3h). When IGF-IR ab was included in SW620 cells, the caspase 3/7 activities significantly decreased (P < 0.01) in both SCM (figure 3g) and SFM (figure 3h) media compared to IGF-I treated groups. In order to check whether IGF-IR antibody neutralization of IGF-I action is a specific effect; a general mouse IgG was included in the experiment. The results (figure 3i and 3j) showed that general mouse IgG was not able to inhibit IGF-I induced caspase activation. This indicates that IGF-IR antibody effect is a specific action.

Bottom Line: The results show that exogenous IGF-I significantly increases activity of caspases 3/7, 8 and 9 in all cell lines used; blocking IGF-I receptor reduce IGF-I-induced caspase activation.Further studies demonstrate that IGF-I induced caspase activation does not result in cell death.The study suggests that caspase activation is not synonymous with apoptosis and that activation of caspases may not necessarily induce cell death.

View Article: PubMed Central - HTML - PubMed

Affiliation: University College London, Division of Surgery and Interventional Science, Royal Free & University College Medical School, Rowland Hill Street, London, UK. shiyu.yang@medsch.ucl.ac.uk

ABSTRACT

Background: Colorectal cancer is the third most common cancer in the western world. Chemotherapy is often ineffective to treat the advanced colorectal cancers due to the chemo-resistance. A major contributor to chemo-resistance is tumour-derived inhibition or avoidance of apoptosis. Insulin-like growth factor I (IGF-I) has been known to play a prominent role in colorectal cancer development and progression. The role of IGF-I in cancer cell apoptosis is not completely understood.

Methods: Using three colorectal cancer cell lines and one muscle cell line, associations between IGF-I and activities of caspase 3/7, 8 and 9 have been examined; the role of insulin-like growth factor I receptor (IGF-IR) in the caspase activation has been investigated.

Results: The results show that exogenous IGF-I significantly increases activity of caspases 3/7, 8 and 9 in all cell lines used; blocking IGF-I receptor reduce IGF-I-induced caspase activation. Further studies demonstrate that IGF-I induced caspase activation does not result in cell death. This is the first report to show that while IGF-I activates caspases 3/7, 8 and 9 it does not cause colorectal cancer cell death.

Conclusion: The study suggests that caspase activation is not synonymous with apoptosis and that activation of caspases may not necessarily induce cell death.

Show MeSH
Related in: MedlinePlus