ABSTRACT
Metastasis is the main cause of colorectal cancer (CRC)-related death, and the 5-year relative survival rate for CRC patients with distant metastasis is only 14%. X-linked inhibitor of apoptosis (XIAP)-associated factor 1 (XAF1) is a zinc-rich protein belonging to the interferon (IFN)-induced gene family. Here, we report a metastasis-promoting role of XAF1 in CRC by acting as a novel adaptor of valosin-containing protein (VCP). XAF1 facilitates VCP-mediated deubiquitination of the E3 ligase RING finger protein 114 (RNF114), which promotes K48-linked ubiquitination and subsequent degradation of junction plakoglobin (JUP). The XAF1-VCP-RNF114-JUP axis is critical for the migration and metastasis of CRC cells. Moreover, we observe correlations between the protein levels of XAF1, RNF114, and JUP in clinical samples. Collectively, our findings reveal an oncogenic function of XAF1 in mCRC and suggest that the XAF1-VCP-RNF114-JUP axis is a potential therapeutic target for CRC treatment.
Subject(s)
Adaptor Proteins, Signal Transducing , Apoptosis Regulatory Proteins , Colorectal Neoplasms , Intracellular Signaling Peptides and Proteins , Humans , Adaptor Proteins, Signal Transducing/metabolism , Apoptosis , Apoptosis Regulatory Proteins/metabolism , Colorectal Neoplasms/genetics , gamma Catenin/metabolism , Intracellular Signaling Peptides and Proteins/metabolism , Neoplasm Proteins/metabolism , Valosin Containing Protein/genetics , Valosin Containing Protein/metabolismABSTRACT
Hepatocellular carcinoma (HCC) is highly resistant to traditional chemotherapeutic approaches, which causes difficulty in the development of effective drugs for the treatment of HCC. Berberine, a major ingredient of Rhizoma coptidis, is a natural alkaloid used in traditional Chinese medicine. Berberine exhibits potent antitumor activity against HCC due to its high efficiency and low toxicity. In the present study, we found that berberine sensitized HepG cells to NF-κB-mediated apoptosis. Berberine exhibited a significant antiproliferation effect on the HepG2 cells and promoted apoptosis. Both qRT-PCR and immunofluorescence staining revealed that berberine reduced the NF-κB p65 levels in HepG2 cells. Moreover, p65 overexpression rescued berberine-induced cell proliferation and prevented HepG2 cells from undergoing apoptosis. These results suggest that berberine inhibits the growth of HepG2 cells by promoting apoptosis through the NF-κB p65 pathway.
