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Knocking-down cyclin A(2) by siRNA suppresses apoptosis and switches differentiation pathways in K562 cells upon administration with doxorubicin.

Wang X, Song Y, Ren J, Qu X - PLoS ONE (2009)

Bottom Line: Upon administration with doxorubicin, K562 cells with reduced cyclin A(2) showed a significant decrease in erythroid differentiation, and a small fraction of cells were differentiated along megakaryocytic and monocyte-macrophage pathways.The results demonstrate the pro-apoptotic role of cyclin A(2) and suggest that cyclin A(2) is a key regulator of cell differentiation.To the best of our knowledge, this is the first report that knocking down expression of one gene switches differentiation pathways of human myeloid leukemia K562 cells.

View Article: PubMed Central - PubMed

Affiliation: Division of Biological Inorganic Chemistry, State Key Laboratory of Rare Earth Resources Utilization, Changchun Institute of Applied Chemistry, Graduate School of the Chinese Academy of Sciences, Chinese Academy of Sciences, Changchun, Jilin, China.

ABSTRACT
Cyclin A(2) is critical for the initiation of DNA replication, transcription and cell cycle regulation. Cumulative evidences indicate that the deregulation of cyclin A(2) is tightly linked to the chromosomal instability, neoplastic transformation and tumor proliferation. Here we report that treatment of chronic myelogenous leukaemia K562 cells with doxorubicin results in an accumulation of cyclin A(2) and follows by induction of apoptotic cell death. To investigate the potential preclinical relevance, K562 cells were transiently transfected with the siRNA targeting cyclin A(2) by functionalized single wall carbon nanotubes. Knocking down the expression of cyclin A(2) in K562 cells suppressed doxorubicin-induced growth arrest and cell apoptosis. Upon administration with doxorubicin, K562 cells with reduced cyclin A(2) showed a significant decrease in erythroid differentiation, and a small fraction of cells were differentiated along megakaryocytic and monocyte-macrophage pathways. The results demonstrate the pro-apoptotic role of cyclin A(2) and suggest that cyclin A(2) is a key regulator of cell differentiation. To the best of our knowledge, this is the first report that knocking down expression of one gene switches differentiation pathways of human myeloid leukemia K562 cells.

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The sub-cellular distribution of cyclin A2 in K562 cells correlated with cell apoptosis.Cells were administered with 0.4 µM DOX for 32 h. A significant fraction of cells underwent apoptosis. Immunofluorescence detection of cyclin A2 was performed as described in Materials and Methods section. A: representative fluorescence microscopy image of K562 cells after treatment. Orange nuclei were observed, where DOX was mostly located; B: representative immunofluorescence microscopy image of K562 cells. Cyclin A2, normally located at nucleus, can be observed in cytoplasm of early and late phases of apoptotic cells. C: representative microscopy image of negative control immunofluorescence in K562 cells. No significant non-specific signal was observed.
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pone-0006665-g006: The sub-cellular distribution of cyclin A2 in K562 cells correlated with cell apoptosis.Cells were administered with 0.4 µM DOX for 32 h. A significant fraction of cells underwent apoptosis. Immunofluorescence detection of cyclin A2 was performed as described in Materials and Methods section. A: representative fluorescence microscopy image of K562 cells after treatment. Orange nuclei were observed, where DOX was mostly located; B: representative immunofluorescence microscopy image of K562 cells. Cyclin A2, normally located at nucleus, can be observed in cytoplasm of early and late phases of apoptotic cells. C: representative microscopy image of negative control immunofluorescence in K562 cells. No significant non-specific signal was observed.

Mentions: Early reports have demonstrated that there is a link between cyclin A2 subcellular localization and its cell function, and the level of cyclin A2 is correlated to cell apoptosis [22], [23], [26]. For clarifying whether the subcellular distribution of cyclin A2 in K562 cells correlates with apoptosis induced by DOX, indirect immunofluorescence detection of cyclin A2 was performed. As shown in Fig. 6A, a significant fraction of cells underwent apoptosis and orange nuclei were observed, where DOX was mostly located. The immunofluorescence labeling of cyclin A2 showed its presence predominantly in the nucleus of control K562 cells (Fig. S4), whereas in cells administered with DOX, cyclin A2 was mainly located at the cytoplasm of early and late phases of apoptotic cells (Fig. 6B). Cyclin A2 labeling was not found in the K562 cells incubated with non-immune serum (Fig. 6C). The results indicated that translocation of cyclin A2 from the nucleus to cytoplasm was connected with its role in apoptosis.


Knocking-down cyclin A(2) by siRNA suppresses apoptosis and switches differentiation pathways in K562 cells upon administration with doxorubicin.

Wang X, Song Y, Ren J, Qu X - PLoS ONE (2009)

The sub-cellular distribution of cyclin A2 in K562 cells correlated with cell apoptosis.Cells were administered with 0.4 µM DOX for 32 h. A significant fraction of cells underwent apoptosis. Immunofluorescence detection of cyclin A2 was performed as described in Materials and Methods section. A: representative fluorescence microscopy image of K562 cells after treatment. Orange nuclei were observed, where DOX was mostly located; B: representative immunofluorescence microscopy image of K562 cells. Cyclin A2, normally located at nucleus, can be observed in cytoplasm of early and late phases of apoptotic cells. C: representative microscopy image of negative control immunofluorescence in K562 cells. No significant non-specific signal was observed.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2721982&req=5

pone-0006665-g006: The sub-cellular distribution of cyclin A2 in K562 cells correlated with cell apoptosis.Cells were administered with 0.4 µM DOX for 32 h. A significant fraction of cells underwent apoptosis. Immunofluorescence detection of cyclin A2 was performed as described in Materials and Methods section. A: representative fluorescence microscopy image of K562 cells after treatment. Orange nuclei were observed, where DOX was mostly located; B: representative immunofluorescence microscopy image of K562 cells. Cyclin A2, normally located at nucleus, can be observed in cytoplasm of early and late phases of apoptotic cells. C: representative microscopy image of negative control immunofluorescence in K562 cells. No significant non-specific signal was observed.
Mentions: Early reports have demonstrated that there is a link between cyclin A2 subcellular localization and its cell function, and the level of cyclin A2 is correlated to cell apoptosis [22], [23], [26]. For clarifying whether the subcellular distribution of cyclin A2 in K562 cells correlates with apoptosis induced by DOX, indirect immunofluorescence detection of cyclin A2 was performed. As shown in Fig. 6A, a significant fraction of cells underwent apoptosis and orange nuclei were observed, where DOX was mostly located. The immunofluorescence labeling of cyclin A2 showed its presence predominantly in the nucleus of control K562 cells (Fig. S4), whereas in cells administered with DOX, cyclin A2 was mainly located at the cytoplasm of early and late phases of apoptotic cells (Fig. 6B). Cyclin A2 labeling was not found in the K562 cells incubated with non-immune serum (Fig. 6C). The results indicated that translocation of cyclin A2 from the nucleus to cytoplasm was connected with its role in apoptosis.

Bottom Line: Upon administration with doxorubicin, K562 cells with reduced cyclin A(2) showed a significant decrease in erythroid differentiation, and a small fraction of cells were differentiated along megakaryocytic and monocyte-macrophage pathways.The results demonstrate the pro-apoptotic role of cyclin A(2) and suggest that cyclin A(2) is a key regulator of cell differentiation.To the best of our knowledge, this is the first report that knocking down expression of one gene switches differentiation pathways of human myeloid leukemia K562 cells.

View Article: PubMed Central - PubMed

Affiliation: Division of Biological Inorganic Chemistry, State Key Laboratory of Rare Earth Resources Utilization, Changchun Institute of Applied Chemistry, Graduate School of the Chinese Academy of Sciences, Chinese Academy of Sciences, Changchun, Jilin, China.

ABSTRACT
Cyclin A(2) is critical for the initiation of DNA replication, transcription and cell cycle regulation. Cumulative evidences indicate that the deregulation of cyclin A(2) is tightly linked to the chromosomal instability, neoplastic transformation and tumor proliferation. Here we report that treatment of chronic myelogenous leukaemia K562 cells with doxorubicin results in an accumulation of cyclin A(2) and follows by induction of apoptotic cell death. To investigate the potential preclinical relevance, K562 cells were transiently transfected with the siRNA targeting cyclin A(2) by functionalized single wall carbon nanotubes. Knocking down the expression of cyclin A(2) in K562 cells suppressed doxorubicin-induced growth arrest and cell apoptosis. Upon administration with doxorubicin, K562 cells with reduced cyclin A(2) showed a significant decrease in erythroid differentiation, and a small fraction of cells were differentiated along megakaryocytic and monocyte-macrophage pathways. The results demonstrate the pro-apoptotic role of cyclin A(2) and suggest that cyclin A(2) is a key regulator of cell differentiation. To the best of our knowledge, this is the first report that knocking down expression of one gene switches differentiation pathways of human myeloid leukemia K562 cells.

Show MeSH
Related in: MedlinePlus