Effect of photodynamic therapy (PDT) on the expression of pro-apoptotic protein Bak in nasopharyngeal carcinoma (NPC).

Abstract

BACKGROUND AND OBJECTIVE:

To investigate the effect of photodynamic therapy (PDT) on expression of the pro-apoptotic gene Bak in nasopharyngeal carcinoma (NPC).

STUDY DESIGN/MATERIALS AND METHODS:

Apoptosis and expression of the pro-apoptotic gene Bak on the tumor tissues from both pre- and post-PDT were determined using the in situ end labeling (ISEL), standard immunohistochemistry technique and western blot, respectively, in 24 patients with either persistent or recurrent NPC after radiotherapy.

RESULTS:

Before PDT, apoptotic index (AI) in tumor tissue was 1.2 +/- 0.6. At 6, 12, 24 and 48 hours after PDT, AI were 6.5 +/- 3.1, 23.6 +/- 8.3, 67.2 +/- 14.2 and 89.3 +/- 8.1, respectively. PDT caused apoptosis in a time-dependent fashion. Immunohistochemical assay indicated that 75% (18/24) of the patients had an upgrade expression of Bak protein in their tumor tissues after PDT. Increases in expression of Bak from PDT were also confirmed by western blot analysis.

CONCLUSIONS:

PDT probably causes NPC cell apoptosis through an upregulation of the pro-apoptotic protein Bak expression.

• Authors: J Lai, Z Tao, J Xiao, Y Yan, X Wang, C Wang, S Zhou, Y Tian
• Journal: Lasers in surgery and medicine (Lasers Surg Med) Vol. 29 Issue 1 Pg. 27-32 ( 2001) ISSN: 0196-8092 [Print] United States
• PMID: 11500859 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)
• Copyright: Copyright 2001 Wiley-Liss, Inc.

Chemical References

• BAK1 protein, human
• Hematoporphyrins
• Membrane Proteins
• Radiation-Sensitizing Agents
• bcl-2 Homologous Antagonist-Killer Protein
• photocarcinorin

Topics

• Adult
• Aged
• Apoptosis
• Blotting, Western
• Carcinoma, Squamous Cell (drug therapy, metabolism)
• Female
• Hematoporphyrins (therapeutic use)
• Humans
• Immunohistochemistry
• Male
• Membrane Proteins (biosynthesis)
• Middle Aged
• Nasopharyngeal Neoplasms (drug therapy, metabolism)
• Photochemotherapy
• Radiation-Sensitizing Agents (therapeutic use)
• Up-Regulation
• bcl-2 Homologous Antagonist-Killer Protein