TY - JOUR
T1 - Identification of Targets of the HIF-1 Inhibitor IDF-11774 Using Alkyne-Conjugated Photoaffinity Probes
AU - Ban, Hyun Seung
AU - Naik, Ravi
AU - Kim, Hwan Mook
AU - Kim, Bo Kyung
AU - Lee, Hongsub
AU - Kim, Inhyub
AU - Ahn, Heechul
AU - Jang, Yerin
AU - Jang, Kyusik
AU - Eo, Yumi
AU - Song, Kyung Bin
AU - Lee, Kyeong
AU - Won, Misun
N1 - Publisher Copyright:
© 2016 American Chemical Society.
PY - 2016/8/17
Y1 - 2016/8/17
N2 - We developed a hypoxia-inducible factor-1 (HIF-1) inhibitor, IDF-11774, as a clinical candidate for cancer therapy. To understand the mechanism of action of IDF-11774, we attempted to isolate target proteins of IDF-11774 using bioconjugated probes. Multifunctional chemical probes containing sites for click conjugation and photoaffinity labeling were designed and synthesized. After fluorescence and photoaffinity labeling of proteins, two-dimensional electrophoresis (2DE) was performed to isolate specific molecular targets of IDF-11774. Heat shock protein (HSP) 70 was identified as a target protein of IDF-11774. We revealed that IDF-11774 inhibited HSP70 chaperone activity by binding to its allosteric pocket, rather than the ATP-binding site in its nucleotide-binding domain (NBD). Moreover, IDF-11774 reduced the oxygen consumption rate (OCR) and ATP production, thereby increasing intracellular oxygen tension. This result suggests that the inhibition of HSP70 chaperone activity by IDF-11774 suppresses HIF-1α refolding and stimulates HIF-1α degradation. Taken together, these findings indicate that IDF-11774-derived chemical probes successfully identified IDF-11774's target molecule, HSP70, and elucidated the mode of action of IDF-11774 in inhibiting HSP70 chaperone activity and stimulating HIF-1α degradation in cancer cells.
AB - We developed a hypoxia-inducible factor-1 (HIF-1) inhibitor, IDF-11774, as a clinical candidate for cancer therapy. To understand the mechanism of action of IDF-11774, we attempted to isolate target proteins of IDF-11774 using bioconjugated probes. Multifunctional chemical probes containing sites for click conjugation and photoaffinity labeling were designed and synthesized. After fluorescence and photoaffinity labeling of proteins, two-dimensional electrophoresis (2DE) was performed to isolate specific molecular targets of IDF-11774. Heat shock protein (HSP) 70 was identified as a target protein of IDF-11774. We revealed that IDF-11774 inhibited HSP70 chaperone activity by binding to its allosteric pocket, rather than the ATP-binding site in its nucleotide-binding domain (NBD). Moreover, IDF-11774 reduced the oxygen consumption rate (OCR) and ATP production, thereby increasing intracellular oxygen tension. This result suggests that the inhibition of HSP70 chaperone activity by IDF-11774 suppresses HIF-1α refolding and stimulates HIF-1α degradation. Taken together, these findings indicate that IDF-11774-derived chemical probes successfully identified IDF-11774's target molecule, HSP70, and elucidated the mode of action of IDF-11774 in inhibiting HSP70 chaperone activity and stimulating HIF-1α degradation in cancer cells.
UR - http://www.scopus.com/inward/record.url?scp=84983608525&partnerID=8YFLogxK
U2 - 10.1021/acs.bioconjchem.6b00305
DO - 10.1021/acs.bioconjchem.6b00305
M3 - Article
C2 - 27386732
AN - SCOPUS:84983608525
SN - 1043-1802
VL - 27
SP - 1911
EP - 1920
JO - Bioconjugate Chemistry
JF - Bioconjugate Chemistry
IS - 8
ER -