Journal: Cancer Biology & Medicine
Article Title: MIIP inhibits clear cell renal cell carcinoma proliferation and angiogenesis via negative modulation of the HIF-2α-CYR61 axis
Figure Lengend Snippet: MIIP is weakly expressed in RCC and associated with progression, prognosis, and the expression of CYR61 and HIF-2α. (A) MIIP, CYR61, and HIF-2α expression in 13 pairs of RCC tissues vs. adjacent non-tumor tissues was detected by Western blot. C: RCC tissue; N: adjacent non-tumor tissue. (B) MIIP, CYR61, and HIF-2α expression in an RCC tissue microarray was detected with immunohistochemistry (scale bar: 50 μm). (C) MIIP, CYR61, and HIF-2α expression levels were quantified with a scoring system. The staining score was calculated by multiplying the stained area (%) score and the intensity score. Expression group: low, score < 9; high, score ≥ 9. Stage refers to WHO histological grade. * P < 0.05; ** P < 0.01, χ 2 test. (D) The Kaplan-Meier curve depicts the relationship between MIIP expression level and OS of patients with RCC, and the P -value was calculated with a stratified log rank test ( P = 0.026). (E) Schematic representation of the MIIP/HIF-2α/CYR61 axis in ccRCC. In normal cells, MIIP promotes HSP90 acetylation through inhibiting HDAC6 activity, thus impairing HSP90’s chaperone function and its binding to HIF-2α, which in turn causes RACK1 binding and subsequent HIF-2α degradation. Meanwhile, under normoxia, VHL promotes HIF-2α ubiquitination and degradation in an oxygen-dependent manner. In RCC, VHL deficiency and MIIP downregulation together cause HIF-2α accumulation, thereby leading to overexpression of CYR61, which in turn contributes to RCC progression.
Article Snippet: The precipitates were resolved with SDS-PAGE and subjected to Western blot with anti-HIF-2α (1:1000, Proteintech/CST), anti-HSP90 (1:1000, Proteintech), anti-RACK1 (1:1000, Proteintech), anti-MIIP, or anti-acetyl lysine (1:1000, Abcam).
Techniques: Expressing, Western Blot, Microarray, Immunohistochemistry, Staining, Activity Assay, Binding Assay, Over Expression