Expression of G1 phase regulators in MG-63 osteosarcoma cell line.

  • Authors:
    • M Merli
    • M S Benassi
    • G Gamberi
    • P Ragazzini
    • M R Sollazzo
    • L Molendini
    • G Magagnoli
    • C Ferrari
    • M C Maltarello
    • P Picci
  • View Affiliations

  • Published online on: June 1, 1999     https://doi.org/10.3892/ijo.14.6.1117
  • Pages: 1117-1138
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Abstract

Cyclins and cyclin-dependent kinases (cdks) form complexes that govern transitions during cell cycle phases. In this study we characterized a human osteosarcoma cell line, MG-63, for the expression level of cyclin D1, cyclin E, cdk4, cdk2, and cell cycle inhibitors pRb and p21. To investigate the role of these proteins we treated MG-63 cells with tumor necrosis factor-alpha (TNF-alpha) and interleukin-6 (IL-6). Cell proliferation analysis demonstrated an increased proliferation of MG-63 cells with IL-6, while TNF-alpha acted as an anti-proliferative agent. Immunoblotting revealed an increased expression of p21 with TNF-alpha and its complex with cdk2. TNF-alpha reduced the expression of the cyclin E-cdk2 complex. TNF-alpha did not affect the amount of cyclin D1, cyclin E, cdk4, cdk2, and of cyclin D1-cdk4 complex. IL-6 decreased p21 expression and its complex with cdk2, while it increased the cyclin E-cdk2 complex. Cyclin D1 and cdk4 expression and their complex did not change after IL-6 treatment, nor did cyclin E and cdk2 protein expression. Hyperphosphorylated/dephosphorylated Rb protein ratio was reduced with TNF-alpha whereas it increased with IL-6. These results may suggest an important role of p21 and of cyclin E-cdk2 complex in the G1 phase regulation through pRb phosphorylation in MG-63 cells.

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Jun 1999
Volume 14 Issue 6

Print ISSN: 1019-6439
Online ISSN:1791-2423

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APA
Merli, M., Benassi, M., Gamberi, G., Ragazzini, P., Sollazzo, M., Molendini, L. ... Picci, P. (1999). Expression of G1 phase regulators in MG-63 osteosarcoma cell line.. International Journal of Oncology, 14, 1117-1138. https://doi.org/10.3892/ijo.14.6.1117
MLA
Merli, M., Benassi, M., Gamberi, G., Ragazzini, P., Sollazzo, M., Molendini, L., Magagnoli, G., Ferrari, C., Maltarello, M., Picci, P."Expression of G1 phase regulators in MG-63 osteosarcoma cell line.". International Journal of Oncology 14.6 (1999): 1117-1138.
Chicago
Merli, M., Benassi, M., Gamberi, G., Ragazzini, P., Sollazzo, M., Molendini, L., Magagnoli, G., Ferrari, C., Maltarello, M., Picci, P."Expression of G1 phase regulators in MG-63 osteosarcoma cell line.". International Journal of Oncology 14, no. 6 (1999): 1117-1138. https://doi.org/10.3892/ijo.14.6.1117