Terpestacin inhibits tumor angiogenesis by targeting UQCRB of mitochondrial complex III and suppressing hypoxia-induced reactive oxygen species production and cellular oxygen sensing

Jung, H. J.; Shim, J. S.; Lee, J.; Song, Y. M.; Park, K. C.; Choi, S. H.; Kim, N. D.; Yoon, J. H.; Mungai, P. T.; Schumacker, P. T.; Kwon, H. J.

J Biol Chem. 2010 Feb 11; 285(15):11584-95


Cellular oxygen sensing is required for hypoxia-inducible factor-1alpha stabilization, which is important for tumor cell survival, proliferation, and angiogenesis. Here we find that terpestacin, a small molecule previously identified in a screen of microbial extracts, binds to the 13.4-kDa subunit (UQCRB) of mitochondrial Complex III, resulting in inhibition of hypoxia-induced reactive oxygen species generation. Consequently, such inhibition blocks hypoxia-inducible factor activation and tumor angiogenesis in vivo, without inhibiting mitochondrial respiration. Overexpression of UQCRB or its suppression using RNA interference demonstrates that it plays a crucial role in the oxygen sensing mechanism that regulates responses to hypoxia. These findings provide a novel molecular basis of terpestacin targeting UQCRB of Complex III in selective suppression of tumor progression.

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