Disseminated castration-resistant prostate cancer (CRPC) is a common disease in men that is characterized by limited survival and resistance to androgen-deprivation therapy. The increase in human epidermal growth factor receptor 2 (HER2) signaling contributes to androgen receptor activity in a subset of patients with CRPC; however, enigmatically, HER2-targeted therapies have demonstrated a lack of efficacy in patients with CRPC. Aberrant glycosylation is a hallmark of cancer and involves key processes that support cancer progression. Using transcriptomic analysis of prostate cancer data sets, histopathologic examination of clinical specimens, and in vivo experiments of xenograft models, we reveal in this study a coordinated increase in glycan-binding protein, galectin-4, specific glycosyltransferases of core 1 synthase, glycoprotein- N-acetylgalactosamine 3-β-galactosyltransferase 1 (C1GALT1) and ST3 beta-galactoside α-2,3-sialyltransferase 1 (ST3GAL1), and resulting mucin-type O-glycans during the progression of CRPC. Furthermore, galectin-4 engaged with C1GALT1-dependent O-glycans to promote castration resistance and metastasis by activating receptor tyrosine kinase signaling and cancer cell stemness properties mediated by SRY-box 9 (SOX9). This galectin-glycan interaction up-regulated the MYC-dependent expression of C1GALT1 and ST3GAL1, which altered cellular mucin-type O-glycosylation to allow for galectin-4 binding. In clinical prostate cancer, high-level expression of C1GALT1 and galectin-4 together predict poor overall survival compared with low-level expression of C1GALT1 and galectin-4. In summary, MYC regulates abnormal O-glycosylation, thus priming cells for binding to galectin-4 and downstream signaling, which promotes castration resistance and metastasis.-Tzeng, S.-F., Tsai, C.-H., Chao, T.-K., Chou, Y.-C., Yang, Y.-C., Tsai, M.-H., Cha, T.-L., Hsiao, P.-W. O-Glycosylation-mediated signaling circuit drives metastatic castration-resistant prostate cancer.

Macrophages play a pivotal role in the immune system through recognition and elimination of microbial pathogens. Toll-like receptors (TLRs) on macrophages interact with microbial substances and initiate signal transduction through intracellular adapters. TLR4, which recognizes the lipopolysaccharides (LPS) on Gram-positive and Gram-negative bacteria, triggers downstream signaling mediators and eventually activates IκB kinase (IKK) complex and mitogen-activated protein kinases (MAPKs) such as p38. Previous reports revealed that, in addition to NF-κB, a core transcription factor of the innate immune response, the induction of some LPS-induced genes in macrophages required another transcription factor whose activity depends on p38. However, these additional transcription factors remain to be identified. In order to identify p38-activated transcription factors that cooperate with NF-κB in response to LPS stimulation, microarrays were used to identify genes regulated by both NF-κB and p38 using wild-type, IKK-depleted, and p38 inhibitor-treated mouse bone marrow-derived macrophages (BMDMs). In silico analysis of transcription factor binding sites was used to predict the potential synergistic transcription factors from the co-expressed genes. Among these genes, NF-κB and C/EBPβ, a p38 downstream transcription factor, were predicted to co-regulate genes in LPS-stimulated BMDMs. Based on the subsequent results of a chromatin immunoprecipitation assay and TNFAIP3 expression in C/EBPβ-ablated macrophages, we demonstrated that Tnfaip3 is regulated by both NF-κB and p38-dependent C/EBPβ. These results identify a novel regulatory mechanism in TLR4-mediated innate immunity.

Hypoxia can lead to solid tumor aggressiveness by driving multiple signaling pathways. Long non-coding RNAs respond to several extrinsic stimuli, causing changes in cancer cells by participating in multiple steps of gene expression. However, genomic profiling of long non-coding RNAs regulated by oxygen in breast cancer remained unclear. Therefore, the aims of this study were to identify oxygen-responsive long non-coding RNAs in breast cancer cells, and to delineate their regulatory mechanisms. The expression profiling of long non-coding RNAs in breast cancer cells growing under normoxic, hypoxic, and re-oxygenated conditions was examined using next-generation sequencing technology. Four hundred and seventy-two lncRNAs oxygen-responsive lncRNAs were identified. After examining the top three differentially expressed lncRNAs in hypoxia, we selected N-Myc Downstream Regulated Gene 1-Overlapping 1 (NDRG1-OT1) for further study, especially the most responsive isoform, NDRG1-OT1_v4. We overexpressed NDRG1-OT1_v4 under normoxia and performed microarray analysis to identify 108 NDRG1-OT1_v4 regulated genes and their functions. Among these genes, we found that both NDRG1 mRNA expression and NDRG1 protein levels were inhibited by NDRG1-OT1_v4. Finally, we used co-immunoprecipitation to show that NDRG1-OT1_v4 destabilizes NDRG1 by promoting ubiquitin-mediated proteolysis. Our findings reveal a new type of epigenetic regulation of NDRG1 by NDRG1-OT1_v4 in breast cancer cells.

Esophageal cancer is one of the leading causes of cancer death in the male population of Eastern Asia. In addition, esophageal squamous cell carcinoma (ESCC) is the major type of esophageal cancer among the world. Owing to the poor overall 5-year survival rate, novel effective treatment strategies are needed. MicroRNAs are important gene regulators that are dysregulated in many cancer types. In our previous study, we applied next-generation sequencing to demonstrate that miR-338-5p was downregulated in the tumor tissue of patients with versus without recurrence. In this study, we further studied the roles of miR-338-5p in ESCC. The expression of endogenous miR-338-5p was at lower levels in ESCC cells compared with normal cells. Functional assays showed that miR-338-5p reduced cell proliferation, colony formation, migration and cisplatin resistance in an ESCC cell line, CE-81T. Potential target genes of miR-338-5p were identified by microarray and prediction tools, and 31 genes were selected. Among these, Fermitin family homolog 2 (FERMT2) plays an oncogenic role in ESCC, so it was chosen for further study. Luciferase assays showed the direct binding between miR-338-5p and the 3′ untranslated region of FERMT2. Silencing of FERMT2 inhibited cell proliferation, colony formation, migration and cisplatin resistance. Pathway analysis revealed that the integrin-linked protein kinase signaling pathway, in which FERMT2 participates, was significantly affected by a miR-338-5p mimic. Our results suggest that miR-338-5p may play an antioncogenic role in ESCC via repressing FERMT2.