Effect of hypericin-mediated photodynamic therapy on the expression of vascular endothelial growth factor in human nasopharyngeal carcinoma

  • Authors:
    • Ramaswamy Bhuvaneswari
    • Yap Yik-Yuen Gan
    • Karen Kar Lye Yee
    • Khee Chee Soo
    • Malini Olivo
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  • Published online on: October 1, 2007     https://doi.org/10.3892/ijmm.20.4.421
  • Pages: 421-428
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Abstract

Photodynamic therapy (PDT) is currently being used as an alternative treatment modality for various types of cancers. PDT involves the selective uptake and retention of a photosensitizer in the tumor followed by light irradiation of an appropriate wavelength to cause the destruction of tumor cells by the formation of cytotoxic reactive oxygen species. The photosensitizer, hypericin, has shown great potential due to its light-dependent tumor destructive properties. However, as hypericin-mediated PDT primarily targets tumor vasculature, it induces certain pro-angiogenic factors such as vascular endothelial growth factor (VEGF) in the tumor tissue as a result of hypoxia. This study examines the role of hypericin-mediated photodynamic therapy in stimulating the expression of key angiogenesis growth factor VEGF in order to elucidate the process of tumor angiogenesis in nasopharyngeal carcinoma xenografts. We also investigated the effect of angiogenesis inhibitor celebrex on human VEGF levels when combined with hypericin-PDT. These studies were conducted on an in vivo human nasopharyngeal xenograft model. VEGF was measured in the control and hypericin-PDT treated tumors. VEGF levels were found to be higher when the tumors were treated at a 1-h drug-light interval compared to a 6-h interval, due to extensive vascular damage. At 72 h post hypericin-PDT, VEGF levels were upregulated indicating the initiation of regrowth in tumors. The use of angiogenesis inhibitor, celebrex, along with hypericin-PDT downregulated the human VEGF levels suggesting that angiogenesis inhibitors can be used to improve the outcome of hypericin-PDT in nasopharyngeal carcinomas.

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October 2007
Volume 20 Issue 4

Print ISSN: 1107-3756
Online ISSN:1791-244X

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Spandidos Publications style
Bhuvaneswari R, Gan YY, Yee KK, Soo KC and Olivo M: Effect of hypericin-mediated photodynamic therapy on the expression of vascular endothelial growth factor in human nasopharyngeal carcinoma. Int J Mol Med 20: 421-428, 2007
APA
Bhuvaneswari, R., Gan, Y.Y., Yee, K.K., Soo, K.C., & Olivo, M. (2007). Effect of hypericin-mediated photodynamic therapy on the expression of vascular endothelial growth factor in human nasopharyngeal carcinoma. International Journal of Molecular Medicine, 20, 421-428. https://doi.org/10.3892/ijmm.20.4.421
MLA
Bhuvaneswari, R., Gan, Y. Y., Yee, K. K., Soo, K. C., Olivo, M."Effect of hypericin-mediated photodynamic therapy on the expression of vascular endothelial growth factor in human nasopharyngeal carcinoma". International Journal of Molecular Medicine 20.4 (2007): 421-428.
Chicago
Bhuvaneswari, R., Gan, Y. Y., Yee, K. K., Soo, K. C., Olivo, M."Effect of hypericin-mediated photodynamic therapy on the expression of vascular endothelial growth factor in human nasopharyngeal carcinoma". International Journal of Molecular Medicine 20, no. 4 (2007): 421-428. https://doi.org/10.3892/ijmm.20.4.421