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The role of apoptotic cell death in the radiosensitising effect of gemcitabine.

Pauwels B, Vermorken JB, Wouters A, Ides J, Van Laere S, Lambrechts HA, Pattyn GG, Vermeulen K, Meijnders P, Lardon F - Br. J. Cancer (2009)

Bottom Line: When cell-cycle distribution returned to pre-treatment levels, an increased induction of apoptosis was observed with activation of caspase 8 and 9 and a reduction of the mitochondrial membrane potential.A role for the cell-cycle perturbations and the induction of apoptosis could be attributed to the radiosensitising effect of gemcitabine.Apoptosis induction was comparable with the apoptotic pathway observed after the TRAIL treatment, that is the involvement of the extrinsic apoptosis pathway.

View Article: PubMed Central - PubMed

Affiliation: Laboratory of Cancer Research and Clinical Oncology, University of Antwerp, Universiteitsplein 1, 2610 Wilrijk, Belgium. bea.pauwels@ua.ac.be

ABSTRACT

Background: The aim of this study was to evaluate the radiosensitising effect of gemcitabine, in terms of cell-cycle progression, induction of apoptosis, and to investigate the molecular events regulating apoptosis.

Methods: Tumour cells were treated with gemcitabine, radiation, or the combination. 0-72 h after treatment, cells were collected for cell-cycle analysis and apoptosis determination. Caspase 8 and 9, Bid and tBid expression were determined by western blot. The mitochondrial membrane potential was determined using flow cytometry. An RT(2) Profiler PCR Array for human apoptotic genes was performed after the combination or TRAIL treatment.

Results: Gemcitabine and radiation resulted in an early S-phase block immediately after treatment, after which the cells moved synchronously through the cell cycle. When cell-cycle distribution returned to pre-treatment levels, an increased induction of apoptosis was observed with activation of caspase 8 and 9 and a reduction of the mitochondrial membrane potential. Gene expression after treatment with radiosensitising conditions was comparable with expression after the TRAIL treatment.

Conclusion: A role for the cell-cycle perturbations and the induction of apoptosis could be attributed to the radiosensitising effect of gemcitabine. Apoptosis induction was comparable with the apoptotic pathway observed after the TRAIL treatment, that is the involvement of the extrinsic apoptosis pathway.

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Cell cycle analysis at different time points after treatment with gemcitabine (8 nM), radiotherapy (4 Gy), or the combination of gemcitabine and radiotherapy.
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fig2: Cell cycle analysis at different time points after treatment with gemcitabine (8 nM), radiotherapy (4 Gy), or the combination of gemcitabine and radiotherapy.

Mentions: In Figure 2, the distribution of ECV304 and H292 cells over the cell cycle phases at different time points is shown. Without treatment, the distribution of cells over the different phases is very similar over time. Treatment with gemcitabine (8 nM) alone resulted in an early S-phase block immediately after treatment, as we reported earlier (Pauwels et al, 2003c) and 8 h later, the amount of S-phase cells increased and 48 h after treatment the cell cycle distribution returned to pre-treatment levels. In ECV304 cells, radiation (4 Gy) caused a G2/M block, which was maximal 16 h after radiotherapy. In H292 cells, radiotherapy resulted in a G2/M block, which was also maximal 16 h after radiotherapy, whereas the amount of G1 cells remained roughly constant at the expense of S-phase cells. 48 h after radiation, the cell cycle distribution returned to pre-treatment levels. Treatment with the combination of gemcitabine and radiotherapy resulted in an early S-phase block immediately after treatment, both in ECV304 and in H292 cells. This block was followed by a synchronous movement of the cells to the G2/M phase. The G2/M block was maximal 24 h after treatment, being 8 h later than after radiotherapy alone. The cell cycle distribution returned to pre-treatment levels 72 h after combination treatment.


The role of apoptotic cell death in the radiosensitising effect of gemcitabine.

Pauwels B, Vermorken JB, Wouters A, Ides J, Van Laere S, Lambrechts HA, Pattyn GG, Vermeulen K, Meijnders P, Lardon F - Br. J. Cancer (2009)

Cell cycle analysis at different time points after treatment with gemcitabine (8 nM), radiotherapy (4 Gy), or the combination of gemcitabine and radiotherapy.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2736812&req=5

fig2: Cell cycle analysis at different time points after treatment with gemcitabine (8 nM), radiotherapy (4 Gy), or the combination of gemcitabine and radiotherapy.
Mentions: In Figure 2, the distribution of ECV304 and H292 cells over the cell cycle phases at different time points is shown. Without treatment, the distribution of cells over the different phases is very similar over time. Treatment with gemcitabine (8 nM) alone resulted in an early S-phase block immediately after treatment, as we reported earlier (Pauwels et al, 2003c) and 8 h later, the amount of S-phase cells increased and 48 h after treatment the cell cycle distribution returned to pre-treatment levels. In ECV304 cells, radiation (4 Gy) caused a G2/M block, which was maximal 16 h after radiotherapy. In H292 cells, radiotherapy resulted in a G2/M block, which was also maximal 16 h after radiotherapy, whereas the amount of G1 cells remained roughly constant at the expense of S-phase cells. 48 h after radiation, the cell cycle distribution returned to pre-treatment levels. Treatment with the combination of gemcitabine and radiotherapy resulted in an early S-phase block immediately after treatment, both in ECV304 and in H292 cells. This block was followed by a synchronous movement of the cells to the G2/M phase. The G2/M block was maximal 24 h after treatment, being 8 h later than after radiotherapy alone. The cell cycle distribution returned to pre-treatment levels 72 h after combination treatment.

Bottom Line: When cell-cycle distribution returned to pre-treatment levels, an increased induction of apoptosis was observed with activation of caspase 8 and 9 and a reduction of the mitochondrial membrane potential.A role for the cell-cycle perturbations and the induction of apoptosis could be attributed to the radiosensitising effect of gemcitabine.Apoptosis induction was comparable with the apoptotic pathway observed after the TRAIL treatment, that is the involvement of the extrinsic apoptosis pathway.

View Article: PubMed Central - PubMed

Affiliation: Laboratory of Cancer Research and Clinical Oncology, University of Antwerp, Universiteitsplein 1, 2610 Wilrijk, Belgium. bea.pauwels@ua.ac.be

ABSTRACT

Background: The aim of this study was to evaluate the radiosensitising effect of gemcitabine, in terms of cell-cycle progression, induction of apoptosis, and to investigate the molecular events regulating apoptosis.

Methods: Tumour cells were treated with gemcitabine, radiation, or the combination. 0-72 h after treatment, cells were collected for cell-cycle analysis and apoptosis determination. Caspase 8 and 9, Bid and tBid expression were determined by western blot. The mitochondrial membrane potential was determined using flow cytometry. An RT(2) Profiler PCR Array for human apoptotic genes was performed after the combination or TRAIL treatment.

Results: Gemcitabine and radiation resulted in an early S-phase block immediately after treatment, after which the cells moved synchronously through the cell cycle. When cell-cycle distribution returned to pre-treatment levels, an increased induction of apoptosis was observed with activation of caspase 8 and 9 and a reduction of the mitochondrial membrane potential. Gene expression after treatment with radiosensitising conditions was comparable with expression after the TRAIL treatment.

Conclusion: A role for the cell-cycle perturbations and the induction of apoptosis could be attributed to the radiosensitising effect of gemcitabine. Apoptosis induction was comparable with the apoptotic pathway observed after the TRAIL treatment, that is the involvement of the extrinsic apoptosis pathway.

Show MeSH
Related in: MedlinePlus