Induction of apoptosis in human bladder cancer cells in vitro and in vivo caused by FTY720 treatment.
OBJECTIVE
FTY720 is a unique immunosuppressant that induces apoptosis in activated lymphocytes but not in other hematopoietic cells. We examined whether FTY720 has anticancer effects on human bladder cancer cells by inducing apoptosis and we investigated its molecular pathway.


METHODS
We used the 3 human bladder cancer cell lines T24, UMUC3 and HT1197, and the human fibroblast derived cell line CRL-2096 (American Type Tissue Collection, Rockville, Maryland) in this study. The difference in drug susceptibility to FTY720 in cancer cells and fibroblasts was examined by MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) and cell growth assays. FTY720 induced apoptosis was determined by morphological analysis under light and electron microscopy, and DNA electrophoresis, and its molecular pathway was evaluated by Western blot analysis focusing on the p42/p44 mitogen activated protein kinase pathway. We then tested the in vivo effect of this agent using 2 mouse models of human bladder cancer xenograft.


RESULTS
FTY720 treatment in vitro induced selective apoptosis in cancer cells at a concentration of less than 10 microM. Morphological analysis revealed features characteristic of apoptosis, including small cytoplasm with fragmented nuclei and condensed chromatin. DNA electrophoresis confirmed apoptosis, as evidenced by a distinct oligosomal ladder. Western blot analysis revealed that the agent significantly inhibited hepatocyte growth factor induced p42/p44 mitogen activated protein kinase activity. The in vivo anticancer effect was clearly confirmed by significantly decreased tumor growth without notable side effects in the 2 xenograft models.


CONCLUSIONS
FTY720 treatment may induce selective apoptosis in vitro as well as in vivo in cancer cells. We suggest that FTY720 is a potent and clinically applicable anticancer agent for bladder cancer.
Azuma
Haruhito
H
Department of Urology, Osaka Medical College, Takatsuki, Japan.
Takahara
Shigero
S
Horie
Shigeo
S
Muto
Satoru
S
Otsuki
Yoshinori
Y
Katsuoka
Yoji
Y
D000818:Animals; D017209:Apoptosis / Q000187:drug effects*; D015153:Blotting, Western; D002455:Cell Division / Q000187:drug effects; D002460:Cell Line; D002470:Cell Survival / Q000187:drug effects; D053938:DNA Fragmentation / Q000187:drug effects; D004273:DNA, Neoplasm / Q000187:drug effects; D004354:Drug Screening Assays, Antitumor; D004789:Enzyme Activation / Q000187:drug effects; D005347:Fibroblasts / Q000166:cytology / Q000187:drug effects; D000068876:Fingolimod Hydrochloride; D017228:Hepatocyte Growth Factor / Q000494:pharmacology; D006801:Humans; D007166:Immunosuppressive Agents / Q000494:pharmacology* / Q000627:therapeutic use; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D019950:Mitogen-Activated Protein Kinase 1 / Q000378:metabolism; D048052:Mitogen-Activated Protein Kinase 3; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism; D009368:Neoplasm Transplantation; D010766:Phosphorylation / Q000187:drug effects; D011409:Propylene Glycols / Q000494:pharmacology* / Q000627:therapeutic use; D013110:Sphingosine / Q000031:analogs & derivatives; D014407:Tumor Cells, Cultured / Q000187:drug effects / Q000473:pathology; D001749:Urinary Bladder Neoplasms / Q000188:drug therapy / Q000235:genetics / Q000473:pathology*
D004273:DNA, Neoplasm; D007166:Immunosuppressive Agents; D011409:Propylene Glycols; D017228:Hepatocyte Growth Factor; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3; D020928:Mitogen-Activated Protein Kinases; D000068876:Fingolimod Hydrochloride; D013110:Sphingosine