Deguelin suppresses cell proliferation via the inhibition of survivin expression and STAT3 phosphorylation in HTLV-1-transformed T cells.
Adult T-cell leukemia (ATL) is an aggressive malignancy of peripheral T cells infected with human T-cell leukemia virus type 1 (HTLV-1). The prognosis of aggressive ATL patients remains poor because of its resistance to conventional chemotherapy. We examined the effect of deguelin, a naturally occurring rotenoid, on HTLV-1-transformed T-cell lines, KUT-1 and MT-2 cells. We found that deguelin suppressed cell proliferation and induced cell death in these cells. Immunoblot analysis showed the inhibition of survivin expression and signal transducers, and activators of transcription (STAT) 3 phosphorylation of both cells. We also observed the cleavage of caspase-3 and poly(ADP-ribose) polymerase (PARP) in deguelin-treated cells, indicating that deguelin induces caspase-dependent apoptosis in these cells. Furthermore, proteasome inhibitor MG132 prevented the down-regulation of survivin expression and STAT3 dephosphorylation by deguelin, suggesting that the action mechanism of deguelin involves the degradation of survivin and phosphorylated STAT3 through the ubiquitin/proteasome pathway. Our data indicate that deguelin presents a potent anti-proliferative effect in part via the down-regulation of survivin expression and STAT3 phosphorylation in HTLV-1-transformed cells. Deguelin merits further investigation as a potential chemotherapeutic agent for ATL.
Ito
Shigeki
S
Hematology & Oncology, Internal Medicine, Iwate Medical University School of Medicine, 19-1 Uchimaru, Morioka, Iwate 020-8505, Japan. shigei@iwate-med.ac.jp
Oyake
Tatsuo
T
Murai
Kazunori
K
Ishida
Yoji
Y
D000970:Antineoplastic Agents / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects; D015153:Blotting, Western; D002460:Cell Line; D049109:Cell Proliferation / Q000187:drug effects*; D002472:Cell Transformation, Viral / Q000187:drug effects; D015536:Down-Regulation; D015490:HTLV-I Infections / Q000188:drug therapy*; D006801:Humans; D051034:Inhibitor of Apoptosis Proteins; D008869:Microtubule-Associated Proteins / Q000096:biosynthesis / Q000187:drug effects*; D010766:Phosphorylation; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012402:Rotenone / Q000031:analogs & derivatives* / Q000494:pharmacology; D050796:STAT3 Transcription Factor / Q000187:drug effects* / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects; D000077022:Survivin; D013601:T-Lymphocytes / Q000187:drug effects / Q000821:virology
D000970:Antineoplastic Agents; C107489:BIRC5 protein, human; D051034:Inhibitor of Apoptosis Proteins; D008869:Microtubule-Associated Proteins; D050796:STAT3 Transcription Factor; D000077022:Survivin; D012402:Rotenone; C107676:deguelin