Project description:Cullin 4B (CUL4B), a scaffold protein that assembles CRL4B ubiquitin ligase complexes, has been reported to be overexpressed in several types of solid tumors and contributes to epigenetic silencing of tumor suppressor. However, its clinical significance and the molecular mechanisms underlying its regulation in gastric cancer (GC) remain largely unknown. Here, we showed that CUL4B was elevated in GC tissues and its overexpression was positively correlated with poor prognosis and lymph node metastasis. CUL4B knockdown in GC cells decreased proliferation, mesenchymal transition and invasion in vitro, as well as tumor growth and metastasis in nude mice, and CUL4B overexpression induced the opposite results. Further studies showed that miR-101 could inhibit CUL4B expression by directly targeting its 3’-UTR and they were inversely correlated in clinical GC specimens. Notably, a positive relationship between CUL4B and HER2 was found in GC clinical specimens, GC cells and GC xenograft tumors. Through bioinformatics analysis of miRNA-seq data and target prediction, we nominated miR-125a as a direct target of CUL4B. ChIP assays demonstrated that CUL4B directly repressed miR-125a expression by physically binding to its promoter. In addition, we confirmed miR-125a is the target of HER2. Consequently, we demonstrated that CUL4B can up-regulate HER2 expression through repressing miR-125a. Most importantly, silencing of HER2 by Herceptin or siRNA partially reversed CUL4B-induced epithelial-to-mesenchymal transition (EMT), cell invasion and metastasis in vitro and in vivo. These findings define a CUL4B-miR-125a-HER2 regulatory mechanism shed light on CUL4B oncogenic mechanisms and reveals promising therapeutic targets for progressive GC. CUL4B proteins are frequently upregulated in human cancer, yet little is known about the underlying molecular mechanisms of CUL4B induced gastric cancer(GC) carcigenesis.Here, we uncover the critical role of CUL4B in gastric cancer growth and metastasis through the regulation of HER2 expression.CUL4B contributes to GC invasion and metastasis by transcriptional repression of HER2 targeting miR-125a, which provide a new insight into how CUL4B regulates GC progression and metastasis.
Project description:Cancer stem-like traits contribute to prostate cancer (PCa) progression and metastasis. Discovering and clarifying the underlying molecular mechanisms associated with PCa stem-like traits would be great beneficial to clinical treatment of advanced PCa. Cullin 4B (CUL4B) is a scaffold protein overexpressed in several solid malignancies. It is known to silence tumor suppressor through post-transcriptional manner. In this study, through gain- and loss-of-function experiments, we showed that CUL4B promotes PCa pluripotency-associated markers expression, sphere formation and anchorage-independent growth ability in virto. Mechanically, we identified BMI1 as a target of CUL4B. CUL4B unregulates BMI1 expression via epigenetically repressing microRNA-200b (miR200b) and microRNA-200c (miR200c). In addition, miR200b and miR200c (miR200b/c) could partially reverse CUL4B-induced BMI1 and pluripotency-associated marker expression. Finally, our study revealed a CUL4B-miR200b/c-BMI1 oncoprotein axis in PCa, which might give novel insight into how CUL4B promotes PCa progression through regulating cancer stem-like traits.
Project description:Expression analysis of gene expression changes in Homo sapiens SGC-7901 cells after knock down of MTA2 (Metastasis-associated protein) or overexpression SNHG5 (snoRNA host gene 5) Investigation of whole genome gene expression level changes in a Homo sapiens gastric carcinoma cells SGC-7901 after knock down MTA2 expression and upregulation of SNHG5
Project description:HRCT1 gene and protein was overexpressed in primary gastric cancer samples with lymphatic metastasis compared to samples with no metastasis.High expression of HRCT1 was also found to be associated with advanced clinical stage, poor overall survival and disease free survival. Overexpression of HRCT1 dramatically enhanced the migration, invasion, and metastatic ability of gastric cancer cells both in vitro and in vivo. HRCT1 was further demonstrated to promote the progression of gastric cancer by activating the HER2-MAPK passway.
Project description:Expression analysis of gene expression changes in Homo sapiens SGC-7901 cells after knock down of MTA2 (Metastasis-associated protein) or overexpression SNHG5 (snoRNA host gene 5) Investigation of whole genome gene expression level changes in a Homo sapiens gastric carcinoma cells SGC-7901 after knock down MTA2 expression and upregulation of SNHG5 A four chip study using total RNA extracted from SGC-7901 cells transfected with siRNA negative control and SGC-7901 cells knock down of MTA2 with siRNA. Each chip measures the expression level of 45033 genes collected from the authoritative data source including NCBI
Project description:This study propose HOXC10 overexpression by reduced DNA methylation promotes gastric cancer progression through regulation of CST1 and S100P.
Project description:Approximately 30% of cases are resistant to TAM, which has become a major obstacle for breast cancer therapy.In this study, we demonstrated that CUL4B promotes TAM resistance in breast cancer cells through miR-32-5p/ER-α36 axis. CUL4B is overexpressed in TAM-resistant breast cancer cells and positively correlates with the levels of ER-α36 protein in human breast cancer specimens. Mechanistically, CUL4B positively regulates ER-α36 expression by epigenetically repressing the transcription of miR-32-5p. These findings provide not only a mechanistic insight into the role of CUL4B in regulating TAM sensitivity but also a potential target for the therapy of breast cancer.
Project description:Given that colorectal cancer stem cells (CCSCs) play key roles in the tumor dormancy, metastasis and relapse, targeting CCSCs is a promising strategy in cancer therapy. Here, we aimed to identify new regulators of CCSCs and found that Cullin 4B (CUL4B), which possesses oncogenic properties in multiple solid tumors, drives the development and metastasis of colon cancer by sustaining cancer stem-like features. Elevated expression of CUL4B was confirmed in colon tumors and was associated with poor overall survival. Inhibition of CUL4B in cancer cell lines and patient-derived tumor organoids led to reduced sphere formation, proliferation and metastasis capacity. Mechanistically, CUL4B coordinates with PRC2 complex to repress miR34a expression, thus up-regulates oncogenes including MYCN and NOTCH1, which are targeted by miR34a. Mutation of miR34a binding sites in the 3'UTR of the oncogenes rescues the phenotype caused by CUL4B depletion. Significant correlations were found between expression of CUL4B and miR34a (negatively), miR34a target genes (positively) in clinical samples from colon cancer patients. Collectively, our work demonstrates that CUL4B functions to repress miR34a in maintaining cancer stemness in CRC and provides a potential therapeutic target.
Project description:The RON receptor tyrosine kinase promotes metastasis by triggering epigenetic reprogramming through the thymine glycosylase MBD4 (RNA-Seq)