Therapeutic effect of photodynamic therapy using PAD-S31 and diode laser on human liver cancer cells.
OBJECTIVE
Photodynamic therapy (PDT) is an effective local cancer treatment which a photosensitizer is administered and the tumor is irradiated with light. We examined the effect of PDT using PAD-S31 as the photosensitizer, and the 670 nm diode laser on human hepatocellular carcinomas (HCCs).


METHODS
Huh-7, HepG2 and Hep3B cell lines were used in the all experiments. Cell viability was determined by a modified MTT assay. Two methods were used for the determination of apoptosis: terminal deoxynucleotidyl transferase (TdT)-mediated dUTP nick-end labeling assay and detection of fragmented mono- and oligo-nucleosomes by enzyme-linked immunosorbent assay. The caspase activity was measured by fluorometric assay. Cytochrome c in cytosolic fraction was determined using a human cytochrome c immunoassay. Xenografts of human oral HCC cells were generated in KSN S1c nude mice.


RESULTS
In vitro PDT showed excellent cytotoxicity that was a function of laser energy, drug concentration and time to the hepatoma cell lines. The combined use of PAD-S31 and laser irradiation showed excellent anti-tumor activity without severe side-effect against human hepatoma xenografts in nude mice. PDT-mediated cell death occurred predominantly by apoptosis in vitro and in vivo. Furthermore, this treatment initiates early cytochrome c release, followed by late caspase-3 and -9 activation.


CONCLUSIONS
Our study demonstrates that PDT using PAD-S31 and the diode laser induces apoptosis that is mediated by cytochrome c release and caspase activation in human liver cancer cell lines. It is expected that this therapy will be clinically useful for the treatment of patients with HCC.
Date
Masataka
M
Department of Pharmacology, Osaka Dental University, Hirakata, Japan. date@cc.osaka-dent.ac.jp
Fukuchi
Kazuhide
K
Namiki
Yoshihisa
Y
Okumura
Akihiko
A
Morita
Shosuke
S
Takahashi
Hiroshi
H
Ohura
Kiyoshi
K
D000818:Animals; D000970:Antineoplastic Agents / Q000494:pharmacology* / Q000627:therapeutic use; D017209:Apoptosis / Q000187:drug effects; D006528:Carcinoma, Hepatocellular / Q000188:drug therapy* / Q000473:pathology; D045744:Cell Line, Tumor / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D006801:Humans; D020287:In Situ Nick-End Labeling; D007834:Lasers; D008113:Liver Neoplasms / Q000188:drug therapy* / Q000473:pathology; D008297:Male; D051379:Mice; D008815:Mice, Inbred Strains; D008819:Mice, Nude; D009368:Neoplasm Transplantation; D009374:Neoplasms, Experimental / Q000188:drug therapy / Q000473:pathology; D010778:Photochemotherapy; D017319:Photosensitizing Agents / Q000494:pharmacology* / Q000627:therapeutic use; D011166:Porphyrins / Q000494:pharmacology* / Q000627:therapeutic use
C446480:13,17-bis(1-carboxypropionyl)carbamoylethyl-3-ethenyl-8-ethoxyiminoethylidene-7-hydroxy-2,7,12,18-tetramethyl porphyrin; D000970:Antineoplastic Agents; D017319:Photosensitizing Agents; D011166:Porphyrins