Long non-coding RNAs (lncRNAs) have a critical role in cancer initiation and progression, and thus may mediate oncogenic or tumor suppressing effects, as well as be a new class of cancer therapeutic targets. We performed high-throughput sequencing of RNA (RNA-seq) to investigate the expression level of lncRNAs and protein-coding genes in 30 esophageal samples, comprised of 15 esophageal squamous cell carcinoma (ESCC) samples and their 15 paired non-tumor tissues. We further developed an integrative bioinformatics method, denoted URW-LPE, to identify key functional lncRNAs that regulate expression of downstream protein-coding genes in ESCC. A number of known onco-lncRNA and many putative novel ones were effectively identified by URW-LPE. Importantly, we identified lncRNA625 as a novel regulator of ESCC cell proliferation, invasion and migration. ESCC patients with high lncRNA625 expression had significantly shorter survival time than those with low expression. LncRNA625 also showed specific prognostic value for patients with metastatic ESCC. Finally, we identified E1A-binding protein p300 (EP300) as a downstream executor of lncRNA625-induced transcriptional responses. These findings establish a catalog of novel cancer-associated functional lncRNAs, which will promote our understanding of lncRNA-mediated regulation in this malignancy.

Hypoxia-inducible factor 1 (HIF-1) is a crucial transcription factor for the cellular adaptive response to hypoxia, which contributes to multiple events in cancer biology. MicroRNAs (miRNAs) are involved in almost all cellular activities such as differentiation, proliferation, and apoptosis. In this work, we use miRNA microarrays to profile miRNA expression in acute myeloid leukemia (AML) cells with inducible HIF-1a expression, and identify 19 differentially expressed miRNAs. Our study shows that HIF-1a represses the expression of miR-17 and miR-20a by downregulating c-Myc expression. These two miRNAs alleviate hypoxia and HIF-1a-induced differentiation of AML cells. More intriguingly, miR-17 and miR-20a directly inhibit the p21 and STAT3 (signal transducer and activator of transcription 3) expression, both of which can reverse miR-17/miR-20a-mediated abrogation of HIF-1a-induced differentiation. Moreover, we show in vivo that miR-20a contributes to HIF-1a-induced differentiation of leukemic cells. Taken together, our results suggest that HIF-1a regulates the miRNA network to interfere with AML cell differentiation, representing a novel molecular mechanism for HIF-1-mediated anti-leukemic action. Hypoxia-inducible factor-1 (HIF-1), a heterodimeric transcriptional factor that consists of the oxygen-sensitive alpha subunit (HIF-1a) and the constitutively expressed beta subunit (HIF-1b), is a master regulator for the cellular adaptive response to oxygen concentration. 1 Under normoxic conditions, proline residues 402 and 564 of the HIF-1a protein are hydroxylated by specific prolyl hydroxylases (PHDs) that utilize O 2 and a-ketoglutarate as co-factors. The hydroxylated HIF-1a protein is subject to ubiquitination by the E3 ubiquitin ligase von Hippel-Lindau (VHL), which leads to its degradation. In contrast, hypoxic conditions cause the accumulation of HIF-1a protein by inhibiting its hydroxylation, and subsequent ubiquitination and degradation. 2 The stabilized HIF-1a protein translocates into the nucleus, where it forms a heterodimer with HIF-1b and modulates the expression of hundreds of genes through binding to hypoxia-responsive elements (HREs; 5 0 -RCGTG-3 0 ) on their promoters. These HIF-1-targeted genes help the cell adapt to hypoxia by influencing processes such as erythropoiesis, angiogenesis, cell metabolism, growth, apoptosis, and differentiation.Intriguingly, HIF-1a has been shown to contribute to the pathogenesis and progression of multiple kinds of diseases, including cancer. 1,3 Although a hypoxic microenvironment is regarded as a hallmark of solid tumors, and hypoxia-stabilized HIF-1a protein contributes to tumor growth, angiogenesis, and metastasis, 4 several groups, including our own, have reported that HIF-1a protein can trigger acute myeloid leukemia (AML) cells to undergo differentiation through a transcription-independent mechanism, inhibiting the progression of AML. [5][6][7][8][9] MicroRNAs (miRNAs) are a distinct class of small noncoding RNAs of around 22 nucleotides in length that posttra...

The aim of this study was to determine how the duration of culture affects the ubiquitination of zona pellucida (ZP) proteins (ZP1, ZP2 and ZP3) during porcine oocyte maturation in vitro. We analysed the changes in ZP protein ubiquitination under three conditions: (i) during oocyte maturation from stage GV to MII; (ii) in oocytes cultured for different periods of time; and (iii) in oocytes treated with an antibody against PSMD4. Our results show that ZP1 and ZP2 are ubiquitinated at the GV stage, while ZP1, ZP2 and ZP3 are ubiquitinated at the MII stage, and band intensities for these proteins were significantly different between the GV and MII stages (p < .05). We also found that ubiquitination occurs in ZP1, ZP2 and ZP3 after cultured for 46, 52, 58 and 64 hr, and that the level of ubiquitinated ZP1 was significantly different in oocytes that were cultured for different time periods. Finally, treatment with an antibody against PSMD4 resulted in a significant decrease in ZP1 ubiquitination (p < .05), without affecting ZP2 or ZP3. The number of attached sperms per oocyte was also significantly different between control and anti-PSMD4-treated groups. Thus, we concluded that ZP1 and ZP2 are ubiquitinated at the GV stage, and ZP1, ZP2 and ZP3 are ubiquitinated at the MII stage. As the duration of culture increases, the ubiquitination levels of ZP proteins decrease. We also found that PSMD4 improves ZP1 ubiquitination during in vitro culture of porcine oocytes and effectively inhibits sperm-oocyte binding.