Identification of Targets of the HIF-1 Inhibitor IDF-11774 Using Alkyne-Conjugated Photoaffinity Probes

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• 作者：Hyun Seung Ban ; Ravi Naik ; Hwan Mook Kim ; Bo-Kyung Kim ; Hongsub Lee ; Inhyub Kim ; Heechul Ahn ; Yerin Jang ; Kyusik Jang ; Yumi Eo ; Kyung Bin Song ; Kyeong Lee ; Misun Won
• 刊名：Bioconjugate Chemistry
• 出版年：2016
• 出版时间：August 17, 2016
• 年：2016
• 卷：27
• 期：8
• 页码：1911-1920
• 全文大小：495K
• 年卷期：0
• ISSN：1520-4812

文摘

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.