Modulation of COX2 and hTERT expression by photodynamic therapy in human colon cancer cells

Christine Li Miu Ngan Yow; Ellie Shihng Meir Chu

doi:10.1117/12.823084

13 July 2009 Modulation of COX2 and hTERT expression by photodynamic therapy in human colon cancer cells

Christine Li Miu Ngan Yow, Ellie Shihng Meir Chu

Proceedings Volume 7380, Photodynamic Therapy: Back to the Future; 738065 (2009) https://doi.org/10.1117/12.823084
Event: 12th World Congress of the International Photodynamic Association, 2009, Seattle, Washington, United States

Abstract

Photodynamic therapy (PDT) was employed as a cancer therapy with photosensitizer (PS)-loaded cancer cells, eradicated by the reactive oxygen species after light activation. Cyclo-oxygenase 2 (COX2) is an enzyme expressed in 80% of colon adenocarcinoma and is one of the targets for effective cancer treatment. There is also uprising evidence that the human telomerase reverse transcriptase (hTERT), a catalytic component of telomerase, is reported as a promising indicator for monitoring cancer treatment. In this study, NPe6 mediated PDT on COX2 induced apoptosis in HT-29 was investigated. The cell cycle changes was analysed by flow cytometry and the hTERT expression at pre and post PDT was evaluated at transcription level by Taqman real time PCR. NPe6-PDT in HT-29 cells demonstrated anti-proliferating effect in a drug and light dose dependent manner. LD₅₀ was achieved at 16μg/mL and 2J/cm² at 4 hour-post treatment with a significant down-regulation of COX2 expression at LD₃₀ and LD₅₀ by immunohistochemical staining (IHC) (p<0.05, One-Way ANOVA). Membrane blebbing was detected in over 60% of cells. 35.2% of treated cells arrested in S-phase at LD₅₀ after 24 hours by flow cytometry. A 0.25- and 0.6-fold down-regulation of hTERT mRNA expression was achieved at LD₃₀ and LD₅₀ respectively by TaqMan real-time PCR. To summarize, NPe6 mediated PDT down-regulated COX2 expression and triggered cell apoptosis. The hTERT can serve as an indicative marker for monitoring NPe6-PDT cancer treatment efficacy.

Citation Download Citation

Christine Li Miu Ngan Yow and Ellie Shihng Meir Chu "Modulation of COX2 and hTERT expression by photodynamic therapy in human colon cancer cells", Proc. SPIE 7380, Photodynamic Therapy: Back to the Future, 738065 (13 July 2009); https://doi.org/10.1117/12.823084

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