ECRG2 Disruption Leads to Centrosome Amplification and Spindle Checkpoint Defects Contributing Chromosome Instability

Abstract

Cancer cells contain an abnormal number of chromosomes (aneuploidy), which is a prevalent form of genetic instability in human cancers. Abnormal amplification of centrosomes and defects of spindle assembly checkpoint are the major causes of chromosome instability in cancer cells. Here we present biochemical evidence to suggest a role of ECRG2, a novel tumor suppressor gene, in maintaining chromosome stability. ECRG2 localized to centrosomes during interphase and kinetochores during mitosis. Further analysis revealed that ECRG2 participates in centrosome amplification in a p53-dependent manner. Depletion of ECRG2 not only destabilized p53, down-regulated p21, and increased the cyclin E/CDK2 activity, thus initiating centrosome amplification, but also abolished the ability of p53 localize to centrosomes. Overexpression of ECRG2 restored the p53-dependent suppression of centrosome duplication. Furthermore, ECRG2-depleted cells show severely disrupted spindle phenotype but fail to maintain the mitotic arrest due to minimal BUBR1 protein levels. Taken together, our results indicate that ECRG2 is important for ensuring centrosome duplication, spindle assembly checkpoint, and accurate chromosome segregation, and its depletion may contribute to chromosome instability and aneuploidy in human cancers.

Suppression of hepatocarcinoma model in vitro and in vivo by ECRG2 delivery using adenoviral vector

“…ECRG2 is important for ensuring centrosome duplication and accurate chromosome segregation, and its disruption leads to centrosome amplification and spindle checkpoint defects, contributing chromosome instability. 11 Using yeast two-hybrid system, ECRG2 was found to interact with . By Ad-ECRG2 infection at gradient intensity, nuclear factor (NF)-kB expression was downregulated and matrix metalloproteinase 2 (MMP-2) was reserved in an inactivated form.…”

ECRG2 Regulates Cell Migration/Invasion through Urokinase-type Plasmin Activator Receptor (uPAR)/β1 Integrin Pathway

“…Reagents-Monoclonal anti-ECRG2 antibody was produced by our laboratory (22,23). Human uPA and uPAR monoclonal antibodies were purchased from American Diagnostica (Greenwich, CT).…”

“…All cells were grown in Dulbecco's modified Eagle's medium with 10% fetal bovine serum, 10 mM Hepes, 2 mM L-glutamine, 1 mM minimal essential medium, and sodium pyruvate. We used a doxycycline-inducible expression system to obtain the conditional expression of ECRG2 in HT1080, MDA-MB-231, and MCF-7 cells (ECRG2-Tet-on) as previously described (23). As shown in supplemental Fig.…”

“…As shown in supplemental Fig. 1A, the stable ECRG2 knockdown cells were generated by infection of the ECRG2-Tet-on cells or Tet-On empty vector control cells with pSUPER.Retro.puro-ECRG2-3ЈUTR small interfering RNA (siRNA) (ECRG2-Teton-3ЈUTR-si) or the pSUPER.Retro.puro-LacZ siRNA retrovirus (Tet-On empty and shRNA control) as described before (23). Colonies showing resistance to puromycin (5 g/ml) were clonally isolated, and an immunoblotting assay was used to screen for the expression or suppression of ECRG2 protein.…”

NMR structure note: human esophageal cancer-related gene 2

“…It has been shown that ECRG2 is a tumor suppressor gene involved in the regulation of cell proliferation, induction of apoptosis, and inhibition of cancer cell migration, invasion and metastasis (Cui et al 2003;Huang et al 2007). ECRG2 also participates in centrosome amplification in a p53-dependent manner and has a role in maintaining chromosome stability (Cheng et al 2008). Recently, it was found that ECRG2 regulates cell migration/invasion through urokinase-type plasmin activator (uPA)/urokinase-type plasmin activator receptor (uPAR) pathway by directly inhibiting uPA/plasmin activity, and may represent a novel therapeutic target for cancer (Huang et al 2007;Cheng et al 2009Cheng et al , 2010Cui et al 2010).…”