Figure S3 from GSK3β-Mediated Expression of CUG-Translated WT1 Is Critical for Tumor Progression

Yoshitomi, Hisae; Lee, Kun Y.; Yao, Ke; Shin, Seung Ho; Zhang, Tianshun; Wang, Qiushi; Paul, Souren; Roh, Eunmiri; Ryu, Joohyun; Chen, Hanyong; Aziz, Faisal; Chakraborty, Abhijit; Bode, Ann M.; Dong, Zigang

doi:10.1158/0008-5472.22426693.v1

00085472can201880-sup-244602_2_supp_6678893_qggggw.pdf (186.66 kB)

Figure S3 from GSK3β-Mediated Expression of CUG-Translated WT1 Is Critical for Tumor Progression

journal contribution

posted on 2023-03-31, 04:00 authored by Hisae Yoshitomi, Kun Y. Lee, Ke Yao, Seung Ho Shin, Tianshun Zhang, Qiushi Wang, Souren Paul, Eunmiri Roh, Joohyun Ryu, Hanyong Chen, Faisal Aziz, Abhijit Chakraborty, Ann M. Bode, Zigang Dong

A cycloheximide (CHX) chase assay was used to detect turnover of cugWT1 proteins. HeLa cells were transfected with V5-cugWT1 wt or mutants (S64A, S68E) with Flag-FBXW4 or Flag-FBXW5 and then treated with CHX (20 μg/mL) to prevent further protein synthesis. Whole cell lysates were harvested and prepared at 0, 3, and 6 h post CHX treatment and visualized by Western blotting.

History

ARTICLE ABSTRACT

The Wilms' tumor 1 (WT1) gene is well known as a chameleon gene. It plays a role as a tumor suppressor in Wilms' tumor but also acts as an oncogene in other cancers. Previously, our group reported that a canonical AUG starting site for the WT1 protein (augWT1) acts as a tumor suppressor, whereas a CUG starting site for the WT1 protein (cugWT1) functions as an oncogene. In this study, we report an oncogenic role of cugWT1 in the AOM/DSS-induced colon cancer mouse model and in a urethane-induced lung cancer model in mice lacking cugWT1. Development of chemically-induced tumors was significantly depressed in cugWT1-deficient mice. Moreover, glycogen synthase kinase 3β promoted phosphorylation of cugWT1 at S64, resulting in ubiquitination and degradation of the cugWT1 associated with the F-box−/− WD repeat-containing protein 8. Overall, our findings suggest that inhibition of cugWT1 expression provides a potential candidate target for therapy. These findings demonstrate that CUG-translated WT1 plays an oncogenic role in vivo, and GSK3β-mediated phosphorylation of cugWT1 induces its ubiquitination and degradation in concert with FBXW8.