Ubiquitin⁃like Protein UBQLN2 Exerts Tumor Suppressor Effect by Inhibiting Activation of Wnt Signaling Pathway in Colon Cancer / 中国生物化学与分子生物学报

ABSTRACT

Colon cancer is a malignant tumor that harms human health. In spite of significant progress in our understanding of the molecular pathogenesis, the prognosis for patients with colon cancer remains poor. Ubiquilin-2 (UBQLN2) is a member of the ubiquitin family, actively implicated in the degradation of misfolded and redundant proteins through the ubiquitin-proteasome system and macroautophagy. However, the role and mechanism of UBQLN2 in colon cancer are not clear. This study was designed to explore the role of UBQLN2 in colon cancer and whether the Wnt pathway is involved. IHC and Western blotting analysis showed lower UBQLN2 expression in colon cancer tissues and cells (P<0. 05), and exhibited a negative correlation of UBQLN2 expression with clinical stage and lymph node metastasis (P< 0. 05). CCK-8 assay and flow cytometry demonstrated that UBQLN2 expression could inhibit colon cancer cell proliferation and promote cell apoptosis (P<0. 05). Western blotting analysis reveals that suppression of UBQLN2 enhances Bcl-2 expression but inhibits Bax and Wnt signaling. Taken together, these results showed that UBQLN2 inhibits proliferation and promotes apoptosis of colorectal cancer cells through suppressing the Wnt signaling pathway.