Jak-STAT3 pathway triggers DICER1 for proteasomal degradation by ubiquitin ligase complex of CUL4ADCAF1 to promote colon cancer development. Issue 2 (1st June 2016)

• Record Type: Journal Article
• Authors: Ren, Weiguo; Shen, Shourong; Sun, Zhenqiang; Shu, Peng; Shen, Xiaohua; Bu, Chibin; Ai, Feiyan; Zhang, Xuemei; Tang, Anliu; Tian, Li; Li, Guiyuan; Li, Xiayu; Ma, Jian
• Is Part Of: Cancer letters. Volume 375:Issue 2(2016)
• Page Start: 209
• Page End: 220
• Publication Date: 2016-06-01
• Subjects: DICER1 -- CUL4ADCAF1 ligase complex -- Jak-STAT3 -- Ubiquitination -- Colon cancer -- IL-6; Cancer -- Periodicals; Neoplasms -- Periodicals; Cancer -- Périodiques; Electronic journals; 616.994
• DOI: 10.1016/j.canlet.2016.02.055
• Languages: English
• ISSNs: 0304-3835

Abstract

Highlights: Jak-STAT3 pathway triggers DICER1 for proteasomal degradation by CUL4A DCAF1 . DICER1 and p-STAT3 expression has close correlation in colon cancer. Lower DICER1 expression in colon cancer correlates with poor survival. Abstract: Chronic intestinal inflammation is closely associated with colon cancer development and STAT3 seems to take center stage in bridging chronic inflammation to colon cancer progress. Here, we discovered that DICER1 was significantly downregulated in response to IL-6 or LPS stimulation and identified a novel mechanism for DICER1 downregulation via proteasomal degradation by ubiquitin ligase complex of CUL4A DCAF1 in colon cancer cells. Meanwhile, PI3K-AKT signaling pathway phosphorylated DICER1 and contributed to its proteasomal degradation. The regulation of DICER1 by CUL4A DCAF1 affected cell growth and apoptosis which is controlled by IL-6 activated Jak-STAT3 pathway. Intervention of CUL4A DCAF1 ubiquitin ligase complex led to fluctuation in expression levels of DICER1 and microRNAs, and thus affected tumor growth in a mouse xenograft model. A panel of microRNAs that were downregulated by IL-6 stimulation was rescued by siRNA-CUL4A, and their predicated functions are involved in regulation of cell proliferation, apoptosis and motility. Furthermore, clinical specimen analysis revealed that decreased DICER1 expression was negatively correlated with STAT3 activation and cancer progression in human colon cancers. DICER1 and p-STAT3 expression levels correlated with 5-year overall survival of colon cancer patients. Consequently, this study proposes that inflammation-induced Jak-STAT3 signaling leads to colon cancer development through proteasomal degradation of DICER1 by ubiquitin ligase complex of CUL4A DCAF1, which suggests a novel therapeutic opportunity for colon cancer.