Mechanism of hypoxia-specific cytotoxicity of procaspase-3 fused with a VHL-mediated protein destruction motif of HIF-1alpha containing Pro564.
Under normoxic conditions the alpha-subunit of hypoxia-inducible factor (HIF-1alpha) protein is targeted for degradation by the von Hippel-Lindau (VHL) tumor suppressor protein acting as an E3 ubiquitin ligase. Recently, we developed a hypoxia-targeting protein, TOP3, which consisted of procaspase-3 with the VHL-mediated protein destruction motif of HIF-1alpha. This design enables procaspase-3 to be regulated similarly with HIF-1alpha, being degraded under normoxia while stabilized under hypoxia. Furthermore, stabilized TOP3 was cleaved by the hypoxic stress-induced endogenous caspases and thus the procaspase-3 was converted to active caspase-3 specifically under hypoxic conditions. These data demonstrated that the VHL-mediated protein destruction motif of HIF-1alpha endowed procaspase-3 with hypoxia-specific cytotoxicity.
Harada
Hiroshi
H
Department of Radiation Oncology and Image-Applied Therapy, Kyoto University Graduate School of Medicine, 54 Kawahara-cho, Shogoin, Sakyo-ku, Kyoto 606-8507, Japan.
Kizaka-Kondoh
Shinae
S
Hiraoka
Masahiro
M
D020816:Amino Acid Motifs; D017209:Apoptosis; D053148:Caspase 3 / Q000235:genetics / Q000378:metabolism*; D015687:Cell Hypoxia; D045744:Cell Line, Tumor; D006801:Humans; D051795:Hypoxia-Inducible Factor 1, alpha Subunit / Q000378:metabolism*; D011392:Proline / Q000235:genetics / Q000378:metabolism*; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D051794:Von Hippel-Lindau Tumor Suppressor Protein / Q000235:genetics / Q000378:metabolism*
D051795:Hypoxia-Inducible Factor 1, alpha Subunit; D011993:Recombinant Fusion Proteins; D011392:Proline; D051794:Von Hippel-Lindau Tumor Suppressor Protein; D053148:Caspase 3