Caspase-3 activation and induction of PARP cleavage by cyclic dipeptide cyclo(Phe-Pro) in HT-29 cells.

Abstract

BACKGROUND:

Cyclo(Phe-Pro) has been shown to inhibit cancer cell growth and induce apoptosis in HT-29 colon cancer cells.

MATERIALS AND METHODS:

The molecular mechanisms mediating cyclo(Phe-Pro)-induced apoptosis in HT-29 cells were investigated. Cells were treated with 5 mM or 10 mM cyclo(Phe-Pro) for varying times. Immunoblot analysis was used to detect poly(ADP-ribose)polymerase (PARP) cleavage. A fluorescence-based enzymatic assay was used to measure caspase-3 activity.

RESULTS:

Cyclo(Phe-Pro) (10 mM) induced time-dependent cleavage of PARP, detected as early as 8 hours post treatment. PARP cleavage was blocked by co-administration with the broad-range caspase inhibitor Z-VAD-FMK Cyclo(Phe-Pro) also induced a time-dependent increase (p < 0.01) in caspase-3 activity. This increase in activity was blocked in the presence of the caspase-3 inhibitor Ac-DEVD-CHO.

CONCLUSION:

These results provide evidence that cyclo(Phe-Pro)-induced apoptosis in HT-29 cells is mediated by a caspase cascade. These findings warrant further investigation into the potential antitumour activity of cyclo(Phe-Pro) and its related cyclic dipeptide derivatives.

• Authors: Seth Clint Brauns, Gill Dealtry, Pieter Milne, Ryno Naudé, Maryna Van de Venter
• Journal: Anticancer research (Anticancer Res) 2005 Nov-Dec Vol. 25 Issue 6B Pg. 4197-202 ISSN: 0250-7005 [Print] Greece
• PMID: 16309216 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Amino Acid Chloromethyl Ketones
• Caspase Inhibitors
• Cysteine Proteinase Inhibitors
• Dipeptides
• Peptides, Cyclic
• benzyloxycarbonylvalyl-alanyl-aspartyl fluoromethyl ketone
• cyclo(phenylalanyl-prolyl)
• Poly(ADP-ribose) Polymerases
• CASP3 protein, human
• Caspase 3
• Caspases

Topics

• Amino Acid Chloromethyl Ketones (pharmacology)
• Caco-2 Cells
• Caspase 3
• Caspase Inhibitors
• Caspases (biosynthesis, metabolism)
• Cysteine Proteinase Inhibitors (pharmacology)
• Dipeptides (pharmacology, toxicity)
• Enzyme Activation (drug effects)
• Enzyme Induction (drug effects)
• HT29 Cells
• Humans
• Peptides, Cyclic (pharmacology, toxicity)
• Poly(ADP-ribose) Polymerases (metabolism)