Effects of metformin on retinoblastoma growth in vitro and in vivo

  • Authors:
    • Katarzyna Brodowska
    • Sofia Theodoropoulou
    • Melissa Meyer Zu Hörste
    • Eleftherios I. Paschalis
    • Kimio Takeuchi
    • Gordon Scott
    • David J. Ramsey
    • Elizabeth Kiernan
    • Mien Hoang
    • Joanna Cichy
    • Joan W. Miller
    • Evangelos S. Gragoudas
    • Demetrios G. Vavvas
  • View Affiliations

  • Published online on: September 11, 2014     https://doi.org/10.3892/ijo.2014.2650
  • Pages: 2311-2324
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Abstract

Recent studies suggest that the anti‑diabetic drug metformin may reduce the risk of cancer and have anti‑proliferative effects for some but not all cancers. In this study, we examined the effects of metformin on human retinoblastoma cell proliferation in vitro and in vivo. Two different human retinoblastoma cell lines (Y79, WERI) were treated with metformin in vitro and xenografts of Y79 cells were established in nu/nu immune‑deficient mice and used to assess the effects of pharmacological levels of metformin in vivo. Metformin inhibited proliferation of the retinoblastoma cells in vitro. Similar to other studies, high concentrations of metformin (mM) blocked the cell cycle in G0‑G1, indicated by a strong decrease of G1 cyclins, especially cyclin D, cyclin‑dependent kinases (4 and 6), and flow cytometry assessment of the cell cycle. This was associated with activation of AMPK, inhibition of the mTOR pathways and autophagy marker LC3B. However, metformin failed to suppress growth of xenografted tumors of Y79 human retinoblastoma cells in nu/nu mice, even when treated with a maximally tolerated dose level achieved in human patients. In conclusion, suprapharmacological levels (mM) of metformin, well above those tolerated in vivo, inhibited the proliferation of retinoblastoma cells in vitro. However, physiological levels of metformin, such as seen in the clinical setting, did not affect the growth of retinoblastoma cells in vitro or in vivo. This suggests that the potential beneficial effects of metformin seen in epidemiological studies may be limited to specific tumor types or be related to indirect effects/mechanisms not observed under acute laboratory conditions.
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December-2014
Volume 45 Issue 6

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

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Spandidos Publications style
Brodowska K, Theodoropoulou S, Meyer Zu Hörste M, Paschalis EI, Takeuchi K, Scott G, Ramsey DJ, Kiernan E, Hoang M, Cichy J, Cichy J, et al: Effects of metformin on retinoblastoma growth in vitro and in vivo. Int J Oncol 45: 2311-2324, 2014
APA
Brodowska, K., Theodoropoulou, S., Meyer Zu Hörste, M., Paschalis, E.I., Takeuchi, K., Scott, G. ... Vavvas, D.G. (2014). Effects of metformin on retinoblastoma growth in vitro and in vivo. International Journal of Oncology, 45, 2311-2324. https://doi.org/10.3892/ijo.2014.2650
MLA
Brodowska, K., Theodoropoulou, S., Meyer Zu Hörste, M., Paschalis, E. I., Takeuchi, K., Scott, G., Ramsey, D. J., Kiernan, E., Hoang, M., Cichy, J., Miller, J. W., Gragoudas, E. S., Vavvas, D. G."Effects of metformin on retinoblastoma growth in vitro and in vivo". International Journal of Oncology 45.6 (2014): 2311-2324.
Chicago
Brodowska, K., Theodoropoulou, S., Meyer Zu Hörste, M., Paschalis, E. I., Takeuchi, K., Scott, G., Ramsey, D. J., Kiernan, E., Hoang, M., Cichy, J., Miller, J. W., Gragoudas, E. S., Vavvas, D. G."Effects of metformin on retinoblastoma growth in vitro and in vivo". International Journal of Oncology 45, no. 6 (2014): 2311-2324. https://doi.org/10.3892/ijo.2014.2650