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Polyphenols act synergistically with doxorubicin and etoposide in leukaemia cell lines

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ABSTRACT

The study aimed to assess the effects of polyphenols when used in combination with doxorubicin and etoposide, and to determine whether polyphenols sensitised leukaemia cells, causing inhibition of cell proliferation, cell cycle arrest and induction of apoptosis. This study is based on findings in solid cancer tumours, which have shown that polyphenols can sensitize cells to chemotherapy, and induce apoptosis and/or cell-cycle arrest. This could enable a reduction of chemotherapy dose and off-target effects, whilst maintaining treatment efficacy. Quercetin, apigenin, emodin, rhein and cis-stilbene were investigated alone and in combination with etoposide and doxorubicin in two lymphoid and two myeloid leukaemia cells lines. Measurements were made of ATP levels (using CellTiter-Glo assay) as an indication of total cell number, cell cycle progression (using propidium iodide staining and flow cytometry) and apoptosis (NucView caspase 3 assay and Hoechst 33342/propidium iodide staining). Effects of combination treatments on caspases 3, 8 and 9 activity were determined using Glo luminescent assays, glutathione levels were measured using the GSH-Glo Glutathione Assay and DNA damage determined by anti-γH2AX staining. Doxorubicin and etoposide in combination with polyphenols synergistically reduced ATP levels, induced apoptosis and increased S and/or G2/M phase cell cycle arrest in lymphoid leukaemia cell lines. However, in the myeloid cell lines the effects of the combination treatments varied; doxorubicin had a synergistic or additive effect when combined with quercetin, apigenin, emodin, and cis-stilbene, but had an antagonistic effect when combined with rhein. Combination treatment caused a synergistic downregulation of glutathione levels and increased DNA damage, driving apoptosis via caspase 8 and 9 activation. However, in myeloid cells where antagonistic effects were observed, this was associated with increased glutathione levels and a reduction in DNA damage and apoptosis. This study has demonstrated that doxorubicin and etoposide activity were enhanced by polyphenols in lymphoid leukaemia cells, however, differential responses were seen in myeloid cells with antagonistic responses seen in some combination therapies.

No MeSH data available.


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Effect of doxorubicin and etoposide on (a and b) ATP levels and (c and d) caspase 3 activity in two lymphoid leukaemia (CCRF-CEM and Jurkat), two myeloid leukaemia (THP-1 and KG-1a) cell lines and two non-tumour control cells (CD133+ HSC and CD34+ HSC). The lowest-significant doses (LSD) which significantly reduced ATP levels and induced apoptosis was determined for each etoposide inhibitor in each cell lines. The '*' indicated LSD in each cell line.
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fig1: Effect of doxorubicin and etoposide on (a and b) ATP levels and (c and d) caspase 3 activity in two lymphoid leukaemia (CCRF-CEM and Jurkat), two myeloid leukaemia (THP-1 and KG-1a) cell lines and two non-tumour control cells (CD133+ HSC and CD34+ HSC). The lowest-significant doses (LSD) which significantly reduced ATP levels and induced apoptosis was determined for each etoposide inhibitor in each cell lines. The '*' indicated LSD in each cell line.

Mentions: Doxorubicin and etoposide induced a dose-dependant decrease in ATP levels and increase in caspase 3 activity in all cell lines although effects on non-tumour control cells were reduced compared with leukaemia cells (Figure 1). The lowest-significant dose (LSD) for doxorubicin and etoposide alone (μM), which reduced ATP levels compared with the vehicle control at 24 h, was dependant on all cell types. The LSD for ATP activity for both doxorubicin and etoposide were: 0.01 μM in Jurkat; 0.01 μM in CCRF-CEM; 0.01 μM in THP-1; 0.4 μM in KG-1a; 0.4 μM in CD34+ HSCs and 0.4 μM in CD133+ HSCs (Figures 1a and b). Similar LSDs were observed for induction of caspase 3 activity although this varied slightly dependant on chemotherapy agent and cell line investigated. For doxorubicin, the LSD for caspase 3 activity were: 0.01 μM in Jurkat; 0.01 μM in CCRF-CEM; 0.4 μM in THP-1; 0.4 μM in KG-1a; 0.4 μM in CD34+ HSCs and 0.4 μM in CD133+ HSCs (Figure 1c). For etoposide, the LSD for caspase 3 activity were: 0.01 μM in Jurkat; 0.01 μM in CCRF-CEM; 0.01 μM in THP-1; 0.4 μM in KG-1a; 0.4 μM in CD34+ HSCs and 0.4 μM in CD133+ HSCs (Figure 1d).


Polyphenols act synergistically with doxorubicin and etoposide in leukaemia cell lines
Effect of doxorubicin and etoposide on (a and b) ATP levels and (c and d) caspase 3 activity in two lymphoid leukaemia (CCRF-CEM and Jurkat), two myeloid leukaemia (THP-1 and KG-1a) cell lines and two non-tumour control cells (CD133+ HSC and CD34+ HSC). The lowest-significant doses (LSD) which significantly reduced ATP levels and induced apoptosis was determined for each etoposide inhibitor in each cell lines. The '*' indicated LSD in each cell line.
© Copyright Policy - open-access
Related In: Results  -  Collection

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Show All Figures
getmorefigures.php?uid=PMC4979421&req=5

fig1: Effect of doxorubicin and etoposide on (a and b) ATP levels and (c and d) caspase 3 activity in two lymphoid leukaemia (CCRF-CEM and Jurkat), two myeloid leukaemia (THP-1 and KG-1a) cell lines and two non-tumour control cells (CD133+ HSC and CD34+ HSC). The lowest-significant doses (LSD) which significantly reduced ATP levels and induced apoptosis was determined for each etoposide inhibitor in each cell lines. The '*' indicated LSD in each cell line.
Mentions: Doxorubicin and etoposide induced a dose-dependant decrease in ATP levels and increase in caspase 3 activity in all cell lines although effects on non-tumour control cells were reduced compared with leukaemia cells (Figure 1). The lowest-significant dose (LSD) for doxorubicin and etoposide alone (μM), which reduced ATP levels compared with the vehicle control at 24 h, was dependant on all cell types. The LSD for ATP activity for both doxorubicin and etoposide were: 0.01 μM in Jurkat; 0.01 μM in CCRF-CEM; 0.01 μM in THP-1; 0.4 μM in KG-1a; 0.4 μM in CD34+ HSCs and 0.4 μM in CD133+ HSCs (Figures 1a and b). Similar LSDs were observed for induction of caspase 3 activity although this varied slightly dependant on chemotherapy agent and cell line investigated. For doxorubicin, the LSD for caspase 3 activity were: 0.01 μM in Jurkat; 0.01 μM in CCRF-CEM; 0.4 μM in THP-1; 0.4 μM in KG-1a; 0.4 μM in CD34+ HSCs and 0.4 μM in CD133+ HSCs (Figure 1c). For etoposide, the LSD for caspase 3 activity were: 0.01 μM in Jurkat; 0.01 μM in CCRF-CEM; 0.01 μM in THP-1; 0.4 μM in KG-1a; 0.4 μM in CD34+ HSCs and 0.4 μM in CD133+ HSCs (Figure 1d).

View Article: PubMed Central - PubMed

ABSTRACT

The study aimed to assess the effects of polyphenols when used in combination with doxorubicin and etoposide, and to determine whether polyphenols sensitised leukaemia cells, causing inhibition of cell proliferation, cell cycle arrest and induction of apoptosis. This study is based on findings in solid cancer tumours, which have shown that polyphenols can sensitize cells to chemotherapy, and induce apoptosis and/or cell-cycle arrest. This could enable a reduction of chemotherapy dose and off-target effects, whilst maintaining treatment efficacy. Quercetin, apigenin, emodin, rhein and cis-stilbene were investigated alone and in combination with etoposide and doxorubicin in two lymphoid and two myeloid leukaemia cells lines. Measurements were made of ATP levels (using CellTiter-Glo assay) as an indication of total cell number, cell cycle progression (using propidium iodide staining and flow cytometry) and apoptosis (NucView caspase 3 assay and Hoechst 33342/propidium iodide staining). Effects of combination treatments on caspases 3, 8 and 9 activity were determined using Glo luminescent assays, glutathione levels were measured using the GSH-Glo Glutathione Assay and DNA damage determined by anti-γH2AX staining. Doxorubicin and etoposide in combination with polyphenols synergistically reduced ATP levels, induced apoptosis and increased S and/or G2/M phase cell cycle arrest in lymphoid leukaemia cell lines. However, in the myeloid cell lines the effects of the combination treatments varied; doxorubicin had a synergistic or additive effect when combined with quercetin, apigenin, emodin, and cis-stilbene, but had an antagonistic effect when combined with rhein. Combination treatment caused a synergistic downregulation of glutathione levels and increased DNA damage, driving apoptosis via caspase 8 and 9 activation. However, in myeloid cells where antagonistic effects were observed, this was associated with increased glutathione levels and a reduction in DNA damage and apoptosis. This study has demonstrated that doxorubicin and etoposide activity were enhanced by polyphenols in lymphoid leukaemia cells, however, differential responses were seen in myeloid cells with antagonistic responses seen in some combination therapies.

No MeSH data available.


Related in: MedlinePlus