EXPRESSIONS OF APOPTOSIS-RELATED PROTEINS IN COLON CANCER CELLS AFTER HYP-INDUCED PHOTOTHERAPY

Coloractal cancer is the third most common cancer and is prominent death factor worlwide. Although the main treatment is a surgery, the alternative suggested treatment method is photodynamic therapy (PDT). Hypericin (HYP) is a well-studied photosensitizier for PDT, however mechanism of action is still unclear. The aim of the present study is to investigate the apoptotic cell mechanism in HT-29 and Caco-2 cells photoactivated with HYP.In the present study, HT-29 (grade-I) and Caco-2 (grade-II) human colon cancer cells treated with 0.04, 0.08 or 0.15 µM HYP and irradiated with (4J/cm2) flourescent lamps. HYP effects were evaluated for 16 and 24 h. Total protein content of cells were measured by Bradford assay. Apoptosis-related proteins including caspase-9, Bcl-2 and Bax expressions were investigated at the mRNA level by real-time PCR for both cells.Protein concentrationdramatically decreasedin all groups HT-29 cellsafter 24 h and Caco-2 cells. However, it increased in 0.15 µM group in Caco-2 cells. Caspase-9 were upregulated for both cells in 24 h incubation. Bcl-2 expression was not observed in HT-29 cells, however Bcl-2 downregulated in Caco-2 cells. Bax expression downregulated in HT-29 cells after 24 h incubation and upregulated in Caco-2 cells after 16 h incubation.In conclusion, Caco-2 and HT-29 colon cancer cells response distinctly to HYP-mediated PDT in terms of apoptosis-related proteins, activation of repair mechanisms and resistance development. This research was partially supported by the Hacettepe University Scientific Research Projects Coordination Unit (09 01 601 011).

Keywords:

EXPRESSIONS OF APOPTOSIS-RELATED PROTEINS IN COLON CANCER CELLS AFTER HYP-INDUCED PHOTOTHERAPY,

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Aysun Kılıç SÜLOĞLU, Elif KARACAOĞLU, Güldeniz SELMANOĞLU Çağatay KARAASLAN
Hacettepe University, Faculty of Science, Department of Biology, Zoology Section, Beytepe, Ankara, Turkey Hacettepe University, Faculty of Science, Department of Biology, Molecular Biology Section, Beytepe, Ankara, Turkey