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Co-inhibition of polo-like kinase 1 and Aurora kinases promotes mitotic catastrophe.

Li J, Hong MJ, Chow JP, Man WY, Mak JP, Ma HT, Poon RY - Oncotarget (2015)

Bottom Line: Using concentrations of inhibitors that did not induce severe mitotic defects on their own, we found that both the metaphase arrest and mitotic slippage induced by inhibitors targeting Aurora A and Aurora B (MK-5108 and Barasertib respectively) were enhanced by a PLK1 inhibitor (BI 2536).We found that PLK1 is overexpressed in cells from nasopharyngeal carcinoma, a highly invasive cancer with poor prognosis, in comparison to normal nasopharyngeal epithelial cells.Nasopharyngeal carcinoma cells were more sensitive to BI 2536 as a single agent and co-inhibition with Aurora kinases than normal cells.

View Article: PubMed Central - PubMed

Affiliation: Division of Life Science, Center for Cancer Research, and State Key Laboratory of Molecular Neuroscience, Hong Kong University of Science and Technology, Clear Water Bay, Hong Kong.

ABSTRACT
Mitosis is choreographed by a number of protein kinases including polo-like kinases and Aurora kinases. As these kinases are frequently dysregulated in cancers, small-molecule inhibitors have been developed for targeted anticancer therapies. Given that PLK1 and Aurora kinases possess both unique functions as well as co-regulate multiple mitotic events, whether pharmacological inhibition of these kinases together can enhance mitotic catastrophe remains an outstanding issue to be determined. Using concentrations of inhibitors that did not induce severe mitotic defects on their own, we found that both the metaphase arrest and mitotic slippage induced by inhibitors targeting Aurora A and Aurora B (MK-5108 and Barasertib respectively) were enhanced by a PLK1 inhibitor (BI 2536). We found that PLK1 is overexpressed in cells from nasopharyngeal carcinoma, a highly invasive cancer with poor prognosis, in comparison to normal nasopharyngeal epithelial cells. Nasopharyngeal carcinoma cells were more sensitive to BI 2536 as a single agent and co-inhibition with Aurora kinases than normal cells. These observations underscore the mechanism and potential benefits of targeting PLK1 and Aurora kinases to induce mitotic catastrophe in cancer cells.

No MeSH data available.


Related in: MedlinePlus

PLK1i cooperates with Aurora kinase inhibitors to induce mitotic catastrophe(A) PLK1i cooperates with AURKAi to induce G2/M delay. HeLa cells were incubated with PLK1i (2.5 nM) and/or AURKAi (250 nM) as indicated. After 24 h, the cells were harvested and analyzed with flow cytometry. The positions of 2N and 4N DNA content are indicated. (B) Mitotic catastrophe induced by PLK1i and AURKAi. Cells were treated as described in panel (A). Lysates were prepared and the indicated proteins were detected with immunoblotting. Note that the PLK1 blot was performed after probing the membrane with AURKA antibodies. Equal loading of lysates was confirmed by immunoblotting for actin. (C) PLK1i cooperates with AURKBi to induce G2/M delay. HeLa cells were incubated with PLK1i (2.5 nM) and/or AURKBi (12.5 nM) as indicated. After 24 h, the cells were harvested and analyzed with flow cytometry. (D) Mitotic catastrophe induced by PLK1i and AURKBi. Cells were treated as described in panel (C). Lysates were prepared and the indicated proteins were detected with immunoblotting. Note that the PLK1 blot was performed after probing the membrane with AURKA antibodies (the positions of PLK1 and AURKA are indicated). Equal loading of lysates was confirmed by immunoblotting for actin.
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Figure 3: PLK1i cooperates with Aurora kinase inhibitors to induce mitotic catastrophe(A) PLK1i cooperates with AURKAi to induce G2/M delay. HeLa cells were incubated with PLK1i (2.5 nM) and/or AURKAi (250 nM) as indicated. After 24 h, the cells were harvested and analyzed with flow cytometry. The positions of 2N and 4N DNA content are indicated. (B) Mitotic catastrophe induced by PLK1i and AURKAi. Cells were treated as described in panel (A). Lysates were prepared and the indicated proteins were detected with immunoblotting. Note that the PLK1 blot was performed after probing the membrane with AURKA antibodies. Equal loading of lysates was confirmed by immunoblotting for actin. (C) PLK1i cooperates with AURKBi to induce G2/M delay. HeLa cells were incubated with PLK1i (2.5 nM) and/or AURKBi (12.5 nM) as indicated. After 24 h, the cells were harvested and analyzed with flow cytometry. (D) Mitotic catastrophe induced by PLK1i and AURKBi. Cells were treated as described in panel (C). Lysates were prepared and the indicated proteins were detected with immunoblotting. Note that the PLK1 blot was performed after probing the membrane with AURKA antibodies (the positions of PLK1 and AURKA are indicated). Equal loading of lysates was confirmed by immunoblotting for actin.

Mentions: Relative low concentrations of the PLK1i and Aurora kinase inhibitors were used with the aim of not inducing mitotic defects on their own. Figure 3A shows that while the cell cycle profiles of cells treated with PLK1i or MK-5108 (AURKAi herein) individually were similar to control cells, a significant G2/M delay was induced after the two chemicals were added together. Protein analysis verified that at these relatively low concentrations, PLK1i and AURKAi individually only increased histone H3Ser10 phosphorylation marginally (Figure 3B). By contrast, histone H3Ser10 phosphorylation and cleavage of PAPR1 and caspase 3 were increased in the presence of both PLK1i and AURKAi, suggesting that the two drugs acted cooperatively to induce mitotic catastrophe. Similarly, Barasertib (AURKBi herein) acted cooperatively with PLK1i to induce accumulation of G2/M population (Figure 3C), phosphorylated histone H3Ser10, and cleaved PARP1 (Figure 3D).


Co-inhibition of polo-like kinase 1 and Aurora kinases promotes mitotic catastrophe.

Li J, Hong MJ, Chow JP, Man WY, Mak JP, Ma HT, Poon RY - Oncotarget (2015)

PLK1i cooperates with Aurora kinase inhibitors to induce mitotic catastrophe(A) PLK1i cooperates with AURKAi to induce G2/M delay. HeLa cells were incubated with PLK1i (2.5 nM) and/or AURKAi (250 nM) as indicated. After 24 h, the cells were harvested and analyzed with flow cytometry. The positions of 2N and 4N DNA content are indicated. (B) Mitotic catastrophe induced by PLK1i and AURKAi. Cells were treated as described in panel (A). Lysates were prepared and the indicated proteins were detected with immunoblotting. Note that the PLK1 blot was performed after probing the membrane with AURKA antibodies. Equal loading of lysates was confirmed by immunoblotting for actin. (C) PLK1i cooperates with AURKBi to induce G2/M delay. HeLa cells were incubated with PLK1i (2.5 nM) and/or AURKBi (12.5 nM) as indicated. After 24 h, the cells were harvested and analyzed with flow cytometry. (D) Mitotic catastrophe induced by PLK1i and AURKBi. Cells were treated as described in panel (C). Lysates were prepared and the indicated proteins were detected with immunoblotting. Note that the PLK1 blot was performed after probing the membrane with AURKA antibodies (the positions of PLK1 and AURKA are indicated). Equal loading of lysates was confirmed by immunoblotting for actin.
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Related In: Results  -  Collection

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Figure 3: PLK1i cooperates with Aurora kinase inhibitors to induce mitotic catastrophe(A) PLK1i cooperates with AURKAi to induce G2/M delay. HeLa cells were incubated with PLK1i (2.5 nM) and/or AURKAi (250 nM) as indicated. After 24 h, the cells were harvested and analyzed with flow cytometry. The positions of 2N and 4N DNA content are indicated. (B) Mitotic catastrophe induced by PLK1i and AURKAi. Cells were treated as described in panel (A). Lysates were prepared and the indicated proteins were detected with immunoblotting. Note that the PLK1 blot was performed after probing the membrane with AURKA antibodies. Equal loading of lysates was confirmed by immunoblotting for actin. (C) PLK1i cooperates with AURKBi to induce G2/M delay. HeLa cells were incubated with PLK1i (2.5 nM) and/or AURKBi (12.5 nM) as indicated. After 24 h, the cells were harvested and analyzed with flow cytometry. (D) Mitotic catastrophe induced by PLK1i and AURKBi. Cells were treated as described in panel (C). Lysates were prepared and the indicated proteins were detected with immunoblotting. Note that the PLK1 blot was performed after probing the membrane with AURKA antibodies (the positions of PLK1 and AURKA are indicated). Equal loading of lysates was confirmed by immunoblotting for actin.
Mentions: Relative low concentrations of the PLK1i and Aurora kinase inhibitors were used with the aim of not inducing mitotic defects on their own. Figure 3A shows that while the cell cycle profiles of cells treated with PLK1i or MK-5108 (AURKAi herein) individually were similar to control cells, a significant G2/M delay was induced after the two chemicals were added together. Protein analysis verified that at these relatively low concentrations, PLK1i and AURKAi individually only increased histone H3Ser10 phosphorylation marginally (Figure 3B). By contrast, histone H3Ser10 phosphorylation and cleavage of PAPR1 and caspase 3 were increased in the presence of both PLK1i and AURKAi, suggesting that the two drugs acted cooperatively to induce mitotic catastrophe. Similarly, Barasertib (AURKBi herein) acted cooperatively with PLK1i to induce accumulation of G2/M population (Figure 3C), phosphorylated histone H3Ser10, and cleaved PARP1 (Figure 3D).

Bottom Line: Using concentrations of inhibitors that did not induce severe mitotic defects on their own, we found that both the metaphase arrest and mitotic slippage induced by inhibitors targeting Aurora A and Aurora B (MK-5108 and Barasertib respectively) were enhanced by a PLK1 inhibitor (BI 2536).We found that PLK1 is overexpressed in cells from nasopharyngeal carcinoma, a highly invasive cancer with poor prognosis, in comparison to normal nasopharyngeal epithelial cells.Nasopharyngeal carcinoma cells were more sensitive to BI 2536 as a single agent and co-inhibition with Aurora kinases than normal cells.

View Article: PubMed Central - PubMed

Affiliation: Division of Life Science, Center for Cancer Research, and State Key Laboratory of Molecular Neuroscience, Hong Kong University of Science and Technology, Clear Water Bay, Hong Kong.

ABSTRACT
Mitosis is choreographed by a number of protein kinases including polo-like kinases and Aurora kinases. As these kinases are frequently dysregulated in cancers, small-molecule inhibitors have been developed for targeted anticancer therapies. Given that PLK1 and Aurora kinases possess both unique functions as well as co-regulate multiple mitotic events, whether pharmacological inhibition of these kinases together can enhance mitotic catastrophe remains an outstanding issue to be determined. Using concentrations of inhibitors that did not induce severe mitotic defects on their own, we found that both the metaphase arrest and mitotic slippage induced by inhibitors targeting Aurora A and Aurora B (MK-5108 and Barasertib respectively) were enhanced by a PLK1 inhibitor (BI 2536). We found that PLK1 is overexpressed in cells from nasopharyngeal carcinoma, a highly invasive cancer with poor prognosis, in comparison to normal nasopharyngeal epithelial cells. Nasopharyngeal carcinoma cells were more sensitive to BI 2536 as a single agent and co-inhibition with Aurora kinases than normal cells. These observations underscore the mechanism and potential benefits of targeting PLK1 and Aurora kinases to induce mitotic catastrophe in cancer cells.

No MeSH data available.


Related in: MedlinePlus