Fasudil-induced hypoxia-inducible factor-1alpha degradation disrupts a hypoxia-driven vascular endothelial growth factor autocrine mechanism in endothelial cells

Keiko Takata, Ken-Ichirou Morishige, Toshifumi Takahashi, Kae Hashimoto, Seiji Tsutsumi, Limei Yin, Tsuyoshi Ohta, Jun Kawagoe, Kazuhiro Takahashi, Hirohisa Kurachi
Molecular Cancer Therapeutics 2008, 7 (6): 1551-61
Hypoxic response of endothelial cells (EC) is an important component of tumor angiogenesis. Especially, hypoxia-inducible factor-1 (HIF-1)-dependent EC-specific mechanism is an essential component of tumor angiogenesis. Recently, the Rho/Rho-associated kinase (ROCK) signaling has been shown to play a key role in HIF-1alpha induction in renal cell carcinoma and trophoblast. The present study was designed to investigate whether low oxygen conditions might modulate HIF-1alpha expression through the Rho/ROCK signaling in human umbilical vascular ECs (HUVEC). Pull-down assay showed that hypoxia stimulated RhoA activity. Under hypoxic conditions, HUVECs transfected with small interfering RNA of RhoA and ROCK2 exhibited decreased levels of HIF-1alpha protein compared with nontargeted small interfering RNA transfectants, whereas HIF-1alpha mRNA levels were not altered. One of ROCK inhibitors, fasudil, inhibited hypoxia-induced HIF-1alpha expression without altering HIF-1alpha mRNA expression. Furthermore, proteasome inhibitor prevented the effect of fasudil on HIF-1alpha expression, and polyubiquitination was enhanced by fasudil. These results suggested that hypoxia-induced HIF-1alpha expression is through preventing HIF-1alpha degradation by activating the Rho/ROCK signaling in ECs. Furthermore, hypoxia induced both vascular endothelial growth factor (VEGF) and VEGF receptor-2 expression through the Rho/ROCK/HIF-1alpha signaling in HUVECs. Thus, augmented VEGF/VEGF receptor-2 autocrine mechanism stimulated HUVEC migration under hypoxic conditions. In summary, the Rho/ROCK/HIF-1alpha signaling is an essential mechanism for hypoxia-driven, VEGF-mediated autocrine loop in ECs. Therefore, fasudil might have the antimigratory effect against ECs in tumor angiogenesis.

Full Text Links

Find Full Text Links for this Article


You are not logged in. Sign Up or Log In to join the discussion.

Related Papers

Remove bar
Read by QxMD icon Read

Save your favorite articles in one place with a free QxMD account.


Search Tips

Use Boolean operators: AND/OR

diabetic AND foot
diabetes OR diabetic

Exclude a word using the 'minus' sign

Virchow -triad

Use Parentheses

water AND (cup OR glass)

Add an asterisk (*) at end of a word to include word stems

Neuro* will search for Neurology, Neuroscientist, Neurological, and so on

Use quotes to search for an exact phrase

"primary prevention of cancer"
(heart or cardiac or cardio*) AND arrest -"American Heart Association"