Effect and mechanism of 5-aminolevulinic acid-mediated photodynamic therapy in esophageal cancer.
5-aminolevulinic acid-mediated photodynamic therapy (ALA-PDT) provides a novel and promising treatment for esophageal cancer. However, its specific mechanism has not been fully elucidated and its efficacy is remarkably varied. This study investigated the effect of ALA-PDT on esophageal squamous carcinoma cell line Eca-109 in vitro and vivo to explore optimal parameters, and evaluated the significance of cell apoptosis, cell cycle, ALA-protoporphyrin IX (ALA-PpIX) subcellular localization, and expression of Bcl-2 and Bax mRNA in cells to understand the mechanism of ALA-PDT for esophageal cancer. How ALA concentration, incubation time, and laser irradiation dose influenced the cell proliferation was determined by MTT assay. ALA-PpIX subcellular localization was analyzed by confocal microscopy. The mRNA changes were detected by quantitative real-time polymerase chain reaction (QRT-PCR). Tumor models transplanted with Eca-109 cells in nude mice were established (n = 10) and killed (n = 4) at 24 h post-PDT for malondialdehyde (MDA) detection and histological study. The remaining mice were measured the tumor size for 3 weeks after treatment. Our data show that ALA-PDT significantly inhibits cell proliferation (p < 0.05), the PDT efficacy depends on the saturation of ALA concentration, incubation time, and laser irradiation dose, and the best effect in tumor destruction is at 7-14 days post-PDT. ALA-PpIX is localized in mitochondria and cytoplasm. ALA-PDT induces cell apoptosis and arrests cell cycle at G0/G1 phase. Bcl-2 is significantly down-regulated while Bax is up-regulated (p < 0.05). The results of this study provide references in choosing clinical optimal PDT parameters and help in better understanding the PDT mechanism for esophageal cancer.
Chen
Xiaohua
X
Department of Oncology, Nanfang Hospital, Southern Medical University, Guangzhou, 510515, People's Republic of China.
Zhao
Peng
P
Chen
Fengsheng
F
Li
Libo
L
Luo
Rongcheng
R
D000622:Aminolevulinic Acid / Q000627:therapeutic use*; D000818:Animals; D017209:Apoptosis / Q000187:drug effects; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects; D004938:Esophageal Neoplasms / Q000188:drug therapy* / Q000235:genetics / Q000378:metabolism / Q000473:pathology; D005260:Female; D019254:Genes, bcl-2; D006801:Humans; D007834:Lasers; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D008819:Mice, Nude; D010778:Photochemotherapy / Q000379:methods*; D017319:Photosensitizing Agents / Q000627:therapeutic use*; D011524:Protoporphyrins / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D012334:RNA, Neoplasm / Q000235:genetics / Q000378:metabolism; D051028:bcl-2-Associated X Protein / Q000235:genetics
C494826:BAX protein, human; D017319:Photosensitizing Agents; D011524:Protoporphyrins; D012333:RNA, Messenger; D012334:RNA, Neoplasm; D051028:bcl-2-Associated X Protein; D000622:Aminolevulinic Acid; C028025:protoporphyrin IX