In:
Cancer Research, American Association for Cancer Research (AACR), Vol. 70, No. 8_Supplement ( 2010-04-15), p. 499-499
Abstract:
Photodynamic therapy (PDT) has been demonstrated as an effect treatment modality for early esophageal cancer by using a photo-sensitizer which induces a cytotoxic photoreaction in tumor cells after exposure to a specific wave-length of light. However, the mechanism is still poorly understood regarding the response to PDT for the patients with esophageal cancer. Epidermal growth factor receptor (EGFR) activation is known to induce resistance to many anti-cancer treatments. In this study, we intend to investigate the role of EGFR in esophageal cancer treated with PDT. The PDT-induced cell death is based on the accumulation of a photosensitizing drug in specific cells. Followed by irradiation with visible light (usually red light), the drug-accumulation cells will induce apoptosis or necrosis. In our study, we observed PDT induced cell death of human esophageal carcinoma cells, CE48T/VGH in a dose-dependent manner by incubating increasing amounts of photosensitizer photofrin (0 to 20 μg/ml) under the expose of 630 nm red light (0 to 180 mJ/ cm2) by MTT assay. We found the protein expression of EGFR was decreased with increased amounts of photofrin. The phenomenon was more obvious under light treatments. EGFR expression was not recovered in the presence of proteasome inhibitors indicating that the reduction of EGFR was not mediated by proteasome-dependent pathway. However, the amount of EGFR mRNA was similar in PDT treated and un-treated cells by RT-PCR analysis. To further clarify the role of EGFR expression in PDT resistant ECa cells, we selected the PDT resistant esophageal cancer (CE48T/VGH) cells by incubated with 15 μg /ml photofrin under the 54 mJ/ cm2 or 108 mJ/ cm2 of red light exposure. At 25 days post PDT treatment, the cells was collected and indicated as PDTR 1-1 and PDTR 1-2 respectively. Compared to wild type CE48T/VGH cells, PDTR 1-1 and PDTR 1-2 display 16% and 13 % resistances respectively when incubated with 15 μg /ml photofrin under 108 mJ/ cm2 light treatment. Correlated with the resistance, we found that EGFR protein expression was increased in both PDTR 1-1 and PDTR 1-2 (about 18% compared to wild type cells). Based on our preliminary findings, EGFR expression may be involved in PDT resistance in esophageal cancer cells. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 499.
Type of Medium:
Online Resource
ISSN:
0008-5472
,
1538-7445
DOI:
10.1158/1538-7445.AM10-499
Language:
English
Publisher:
American Association for Cancer Research (AACR)
Publication Date:
2010
detail.hit.zdb_id:
2036785-5
detail.hit.zdb_id:
1432-1
detail.hit.zdb_id:
410466-3
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