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Down-regulation of the PI3K/Akt signaling pathway and induction of apoptosis in CA46 Burkitt lymphoma cells by baicalin.

Huang Y, Hu J, Zheng J, Li J, Wei T, Zheng Z, Chen Y - J. Exp. Clin. Cancer Res. (2012)

Bottom Line: Colony formation was almost fully suppressed at 10 μM baicalin.Additionally, baicalin was found to down-regulate anti-apoptotic and up-regulate apoptotic components of the phosphatidylinositide-3-kinase (PI3K)/serine/threonine kinase (Akt) signaling pathway.The concentrations at which baicalin altered expression of components of the PI3K/Akt pathway in CA46 cells were comparable to those that suppressed growth and induced apoptosis, supporting the hypothesis that the observed growth-inhibitory and apoptosis-inducing actions of baicalin in these cells are mediated by down-regulation of this pathway.

View Article: PubMed Central - HTML - PubMed

Affiliation: Fujian Institute of Hematology, Fujian Provincial Key Laboratory of Hematology, Fujian Medical University Union Hospital, 29 Xinquan Road, Fuzhou, 350000 Fujian, China.

ABSTRACT

Background: Baicalin, a flavone present in Scutellaria baicalensis Georgi, inhibits the growth of human leukemia and myeloma cells through induction of apoptosis.

Methods: The present study was undertaken to ascertain whether cultured Burkitt lymphoma cells undergo apoptosis when treated with baicalin. Growth rates were measured using MTT and colony formation assays, and induction of apoptosis was quantified using Annexin V and DNA fragmentation assays. Mechanisms underlying observed growth suppression were examined using Western blotting.

Results: Treatment of CA46 Burkitt lymphoma cells with baicalin for 48 h markedly decreased the rate of cell proliferation; an IC50 value of 10 μM was obtained. Colony formation was almost fully suppressed at 10 μM baicalin. CA46 cells underwent apoptosis in response to baicalin treatment as evidenced by an increase in the percentage of cells stainable with Annexin V, by increased DNA fragmentation, and by activation of the intrinsic (mitochondrial) pathway for cell death as characterized by increased expression of the cleaved forms of caspase-9, caspase-3, and poly (ADP-ribose) polymerase. Additionally, baicalin was found to down-regulate anti-apoptotic and up-regulate apoptotic components of the phosphatidylinositide-3-kinase (PI3K)/serine/threonine kinase (Akt) signaling pathway.

Conclusions: The concentrations at which baicalin altered expression of components of the PI3K/Akt pathway in CA46 cells were comparable to those that suppressed growth and induced apoptosis, supporting the hypothesis that the observed growth-inhibitory and apoptosis-inducing actions of baicalin in these cells are mediated by down-regulation of this pathway.

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Proliferation of CA46 cells in the absence and presence of baicalin. Cells were seeded at a density of 1 × 104/well and treated with baicalin at the concentrations and for the times indicated. Cytotoxicity was determined according to the MTT assay. Sampling was performed in triplicate for each experimental condition, and findings are expressed as means ± standard deviation for three independent experiments. (A) Proliferation as a function of incubation time and baicalin concentration. Absorbance maxima are provided on the ordinate. (B) Rates of proliferation as a function of baicalin concentration. Cells were treated for 48 h with baicalin at the concentrations indicated. Proliferation rates were determined as described in Materials and methods. *P <0.01 compared to the solvent control; †P <0.01 compared to 5 μM baicalin; ‡P <0.01 compared to 10 μM baicalin.
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Figure 1: Proliferation of CA46 cells in the absence and presence of baicalin. Cells were seeded at a density of 1 × 104/well and treated with baicalin at the concentrations and for the times indicated. Cytotoxicity was determined according to the MTT assay. Sampling was performed in triplicate for each experimental condition, and findings are expressed as means ± standard deviation for three independent experiments. (A) Proliferation as a function of incubation time and baicalin concentration. Absorbance maxima are provided on the ordinate. (B) Rates of proliferation as a function of baicalin concentration. Cells were treated for 48 h with baicalin at the concentrations indicated. Proliferation rates were determined as described in Materials and methods. *P <0.01 compared to the solvent control; †P <0.01 compared to 5 μM baicalin; ‡P <0.01 compared to 10 μM baicalin.

Mentions: Baicalin inhibited the proliferation of CA46 cells in a concentration- and time-dependent manner, with almost complete inhibition observed at 48–96 h of treatment with 20–40 μM drug (Figure 1A). An IC50 of 10 μM was obtained (Figure 1B). After 48 h of treatment, rates of proliferation declined in a baicalin concentration-dependent manner, with 15.5 ± 4.7% and 89.4 ± 2.8% inhibitions observed at 5 and 40 μM drug, respectively. Baicalin also suppressed formation of colonies of CA46 cells at 10 days post-seeding (Figures 2A and 2B). Control preparations formed colonies at a rate of 36.2 ± 4.0%. In contrast, rates of colony formation for preparations treated with baicalin at 5 and 10 μM were 14.0 ± 2.3% and 0.5 ± 0.5%, respectively (P <0.01).


Down-regulation of the PI3K/Akt signaling pathway and induction of apoptosis in CA46 Burkitt lymphoma cells by baicalin.

Huang Y, Hu J, Zheng J, Li J, Wei T, Zheng Z, Chen Y - J. Exp. Clin. Cancer Res. (2012)

Proliferation of CA46 cells in the absence and presence of baicalin. Cells were seeded at a density of 1 × 104/well and treated with baicalin at the concentrations and for the times indicated. Cytotoxicity was determined according to the MTT assay. Sampling was performed in triplicate for each experimental condition, and findings are expressed as means ± standard deviation for three independent experiments. (A) Proliferation as a function of incubation time and baicalin concentration. Absorbance maxima are provided on the ordinate. (B) Rates of proliferation as a function of baicalin concentration. Cells were treated for 48 h with baicalin at the concentrations indicated. Proliferation rates were determined as described in Materials and methods. *P <0.01 compared to the solvent control; †P <0.01 compared to 5 μM baicalin; ‡P <0.01 compared to 10 μM baicalin.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3403945&req=5

Figure 1: Proliferation of CA46 cells in the absence and presence of baicalin. Cells were seeded at a density of 1 × 104/well and treated with baicalin at the concentrations and for the times indicated. Cytotoxicity was determined according to the MTT assay. Sampling was performed in triplicate for each experimental condition, and findings are expressed as means ± standard deviation for three independent experiments. (A) Proliferation as a function of incubation time and baicalin concentration. Absorbance maxima are provided on the ordinate. (B) Rates of proliferation as a function of baicalin concentration. Cells were treated for 48 h with baicalin at the concentrations indicated. Proliferation rates were determined as described in Materials and methods. *P <0.01 compared to the solvent control; †P <0.01 compared to 5 μM baicalin; ‡P <0.01 compared to 10 μM baicalin.
Mentions: Baicalin inhibited the proliferation of CA46 cells in a concentration- and time-dependent manner, with almost complete inhibition observed at 48–96 h of treatment with 20–40 μM drug (Figure 1A). An IC50 of 10 μM was obtained (Figure 1B). After 48 h of treatment, rates of proliferation declined in a baicalin concentration-dependent manner, with 15.5 ± 4.7% and 89.4 ± 2.8% inhibitions observed at 5 and 40 μM drug, respectively. Baicalin also suppressed formation of colonies of CA46 cells at 10 days post-seeding (Figures 2A and 2B). Control preparations formed colonies at a rate of 36.2 ± 4.0%. In contrast, rates of colony formation for preparations treated with baicalin at 5 and 10 μM were 14.0 ± 2.3% and 0.5 ± 0.5%, respectively (P <0.01).

Bottom Line: Colony formation was almost fully suppressed at 10 μM baicalin.Additionally, baicalin was found to down-regulate anti-apoptotic and up-regulate apoptotic components of the phosphatidylinositide-3-kinase (PI3K)/serine/threonine kinase (Akt) signaling pathway.The concentrations at which baicalin altered expression of components of the PI3K/Akt pathway in CA46 cells were comparable to those that suppressed growth and induced apoptosis, supporting the hypothesis that the observed growth-inhibitory and apoptosis-inducing actions of baicalin in these cells are mediated by down-regulation of this pathway.

View Article: PubMed Central - HTML - PubMed

Affiliation: Fujian Institute of Hematology, Fujian Provincial Key Laboratory of Hematology, Fujian Medical University Union Hospital, 29 Xinquan Road, Fuzhou, 350000 Fujian, China.

ABSTRACT

Background: Baicalin, a flavone present in Scutellaria baicalensis Georgi, inhibits the growth of human leukemia and myeloma cells through induction of apoptosis.

Methods: The present study was undertaken to ascertain whether cultured Burkitt lymphoma cells undergo apoptosis when treated with baicalin. Growth rates were measured using MTT and colony formation assays, and induction of apoptosis was quantified using Annexin V and DNA fragmentation assays. Mechanisms underlying observed growth suppression were examined using Western blotting.

Results: Treatment of CA46 Burkitt lymphoma cells with baicalin for 48 h markedly decreased the rate of cell proliferation; an IC50 value of 10 μM was obtained. Colony formation was almost fully suppressed at 10 μM baicalin. CA46 cells underwent apoptosis in response to baicalin treatment as evidenced by an increase in the percentage of cells stainable with Annexin V, by increased DNA fragmentation, and by activation of the intrinsic (mitochondrial) pathway for cell death as characterized by increased expression of the cleaved forms of caspase-9, caspase-3, and poly (ADP-ribose) polymerase. Additionally, baicalin was found to down-regulate anti-apoptotic and up-regulate apoptotic components of the phosphatidylinositide-3-kinase (PI3K)/serine/threonine kinase (Akt) signaling pathway.

Conclusions: The concentrations at which baicalin altered expression of components of the PI3K/Akt pathway in CA46 cells were comparable to those that suppressed growth and induced apoptosis, supporting the hypothesis that the observed growth-inhibitory and apoptosis-inducing actions of baicalin in these cells are mediated by down-regulation of this pathway.

Show MeSH
Related in: MedlinePlus