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Knock-down of core proteins regulating microRNA biogenesis has no effect on sensitivity of lung cancer cells to ionizing radiation.

Surova O, Akbar NS, Zhivotovsky B - PLoS ONE (2012)

Bottom Line: We found that Drosha and Dicer were expressed at higher levels in radioresistant but not in sensitive cell lines.However, down-regulation of either Dicer or Drosha had no effect on the sensitivity of cells to irradiation.Elimination of components of the RNA-induced silencing complex Ago2 and Tudor staphylococcal nuclease also did not sensitize cells to the same treatment.

View Article: PubMed Central - PubMed

Affiliation: Institute of Environmental Medicine, Division of Toxicology, Karolinska Institutet, Stockholm, Sweden.

ABSTRACT
Recent studies underline the important role of microRNAs (miRNA) in the development of lung cancer. The main regulators of miRNA biogenesis are the ribonucleases Drosha, Dicer and Ago2. Here the role of core proteins of miRNA biogenesis machinery in the response of human non-small and small cell lung carcinoma cell lines to treatment with ionizing radiation was assessed. We found that Drosha and Dicer were expressed at higher levels in radioresistant but not in sensitive cell lines. However, down-regulation of either Dicer or Drosha had no effect on the sensitivity of cells to irradiation. Elimination of components of the RNA-induced silencing complex Ago2 and Tudor staphylococcal nuclease also did not sensitize cells to the same treatment. Thus, modulation of miRNA biogenesis machinery is not sufficient to increase the radiosensitivity of lung tumors and other strategies are required to combat lung cancer.

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Expression of components of miRNA machinery in NSCLC following treatment with ionizing radiation.The cleavage of PARP and the level of expression of Drosha, Dicer, exportin 5 (XPO5), Tudor-SN (TSN), protein activator of the interferon-induced protein kinase (PACT), and fragile X mental retardation syndrome-related protein 1 (FXR1) in U1810, H661 and H23 cells were detected by Western blot at 6, 24 and 48 h post-irradiation with 8 Gy. Equal loading was verified using anti-β-actin antibodies. Data are representative of three independent experiments.
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pone-0033134-g002: Expression of components of miRNA machinery in NSCLC following treatment with ionizing radiation.The cleavage of PARP and the level of expression of Drosha, Dicer, exportin 5 (XPO5), Tudor-SN (TSN), protein activator of the interferon-induced protein kinase (PACT), and fragile X mental retardation syndrome-related protein 1 (FXR1) in U1810, H661 and H23 cells were detected by Western blot at 6, 24 and 48 h post-irradiation with 8 Gy. Equal loading was verified using anti-β-actin antibodies. Data are representative of three independent experiments.

Mentions: To further investigate the role of miRNA machinery components in the response of LC cells to irradiation, two RR cell lines (U1810 and H661) and one RS line (H23) from the panel of NSCLC were subjected to gamma irradiation and protein expression was analyzed 6, 24 and 48 h after treatment. As expected, massive apoptotic cell death was observed in H23 at 6 h after ionizing radiation, as assessed by the cleavage of PARP, whereas H661 and U1810 responded to treatment at later time points after 24 and 48 h, respectively (Figure 2). No visible changes in expression of any of the studied proteins were detected either in RR or RS cells, as measured by Western blot at 6, 24 and 48 h after IR treatment (Figure 2). Thus, gamma irradiation does not affect the expression of core proteins of the miRNA machinery in NSCLC regardless of the RR or RS phenotype of these cancer cells.


Knock-down of core proteins regulating microRNA biogenesis has no effect on sensitivity of lung cancer cells to ionizing radiation.

Surova O, Akbar NS, Zhivotovsky B - PLoS ONE (2012)

Expression of components of miRNA machinery in NSCLC following treatment with ionizing radiation.The cleavage of PARP and the level of expression of Drosha, Dicer, exportin 5 (XPO5), Tudor-SN (TSN), protein activator of the interferon-induced protein kinase (PACT), and fragile X mental retardation syndrome-related protein 1 (FXR1) in U1810, H661 and H23 cells were detected by Western blot at 6, 24 and 48 h post-irradiation with 8 Gy. Equal loading was verified using anti-β-actin antibodies. Data are representative of three independent experiments.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3316564&req=5

pone-0033134-g002: Expression of components of miRNA machinery in NSCLC following treatment with ionizing radiation.The cleavage of PARP and the level of expression of Drosha, Dicer, exportin 5 (XPO5), Tudor-SN (TSN), protein activator of the interferon-induced protein kinase (PACT), and fragile X mental retardation syndrome-related protein 1 (FXR1) in U1810, H661 and H23 cells were detected by Western blot at 6, 24 and 48 h post-irradiation with 8 Gy. Equal loading was verified using anti-β-actin antibodies. Data are representative of three independent experiments.
Mentions: To further investigate the role of miRNA machinery components in the response of LC cells to irradiation, two RR cell lines (U1810 and H661) and one RS line (H23) from the panel of NSCLC were subjected to gamma irradiation and protein expression was analyzed 6, 24 and 48 h after treatment. As expected, massive apoptotic cell death was observed in H23 at 6 h after ionizing radiation, as assessed by the cleavage of PARP, whereas H661 and U1810 responded to treatment at later time points after 24 and 48 h, respectively (Figure 2). No visible changes in expression of any of the studied proteins were detected either in RR or RS cells, as measured by Western blot at 6, 24 and 48 h after IR treatment (Figure 2). Thus, gamma irradiation does not affect the expression of core proteins of the miRNA machinery in NSCLC regardless of the RR or RS phenotype of these cancer cells.

Bottom Line: We found that Drosha and Dicer were expressed at higher levels in radioresistant but not in sensitive cell lines.However, down-regulation of either Dicer or Drosha had no effect on the sensitivity of cells to irradiation.Elimination of components of the RNA-induced silencing complex Ago2 and Tudor staphylococcal nuclease also did not sensitize cells to the same treatment.

View Article: PubMed Central - PubMed

Affiliation: Institute of Environmental Medicine, Division of Toxicology, Karolinska Institutet, Stockholm, Sweden.

ABSTRACT
Recent studies underline the important role of microRNAs (miRNA) in the development of lung cancer. The main regulators of miRNA biogenesis are the ribonucleases Drosha, Dicer and Ago2. Here the role of core proteins of miRNA biogenesis machinery in the response of human non-small and small cell lung carcinoma cell lines to treatment with ionizing radiation was assessed. We found that Drosha and Dicer were expressed at higher levels in radioresistant but not in sensitive cell lines. However, down-regulation of either Dicer or Drosha had no effect on the sensitivity of cells to irradiation. Elimination of components of the RNA-induced silencing complex Ago2 and Tudor staphylococcal nuclease also did not sensitize cells to the same treatment. Thus, modulation of miRNA biogenesis machinery is not sufficient to increase the radiosensitivity of lung tumors and other strategies are required to combat lung cancer.

Show MeSH
Related in: MedlinePlus