Analysis of apoptotic effects induced by photodynamic therapy in a human biliary cancer cell line.
BACKGROUND
Photodynamic therapy (PDT) is a relatively new approach for the treatment of biliary tract carcinoma, and its effects have not been investigated in detail to date. This study investigated the mechanisms of human biliary cancer cell death by PDT by focusing on apoptosis induction in vitro and in vivo.


METHODS
In vitro, NOZ cells were incubated with porfimer sodium (Photofrin) for up to 24 hours before exposure to laser light. Cell viability was assessed using a methyltetrazolium assay after PDT. DNA fragmentation, cell cycle analysis and caspase-3 activity assay were performed to evaluate apoptotic cells induced by PDT. In vivo, DNA fragmentation was detected by TUNEL assay.


RESULTS
DNA ladder formation and activation of caspase-3 were observed within 24 hours. The proportion of cells with DNA fragmentation on flow cytometric analysis was increased significantly to 22.2% at 24 hours after PDT. In the in vivo model, TUNEL-positive cells began to increase in the implanted tumour from 6 hours after PDT, and peaked 12 hours later.


CONCLUSIONS
PDT with Photofrin in this human biliary cancer cell line has antitumor effects and induces apoptotic cell death after PDT.
Nonaka
Takashi
T
Department of Regenerative Oral Surgery, Nagasaki University Graduate School of Biomedical Sciences, 1-7-1 Sakamoto, Nagasaki 852-8588, Japan. mnonaka@nagasaki-u.ac.jp
Nanashima
Atsushi
A
Nonaka
Mihoko
M
Uehara
Masataka
M
Isomoto
Hajime
H
Asahina
Izumi
I
Nagayasu
Takeshi
T
D000818:Animals; D017209:Apoptosis / Q000187:drug effects*; D053148:Caspase 3 / Q000378:metabolism; D002453:Cell Cycle / Q000187:drug effects; D045744:Cell Line, Tumor; D002470:Cell Survival / Q000187:drug effects; D005706:Gallbladder Neoplasms / Q000188:drug therapy* / Q000473:pathology; D006801:Humans; D051379:Mice; D008807:Mice, Inbred BALB C; D010778:Photochemotherapy; D023041:Xenograft Model Antitumor Assays
D053148:Caspase 3