Long noncoding RNA SNHG4 promotes the malignant progression of hepatocellular carcinoma through the miR-211-5p/CREB5 axis.

BACKGROUND AND AIMS: Hepatocellular carcinoma (HCC) is one of the main death-leading malignant tumors which deserve in-depth explorations to uncover the underlying molecular mechanisms. Plenty of proofs have revealed that long noncoding RNAs (lncRNAs) participate in malignancy and progression of HCC. Nevertheless, the definite role of lncRNA-SNHG4 in HCC remains vague. METHODS: To figure out the role of SNHG4 in HCC, the bioinformatics analysis and functional assays and in vivo assay were performed. RESULTS: Our findings demonstrated that the data from The Cancer Genome Atlas (TCGA) displayed that the higher expression of lncRNA SNHG4 was detected in HCC tissues, which predicted the poor prognosis. The upregulation of SNHG4 was positively associated with worse clinicopathological characteristics. The functional experiments were performed to identify the role of SNHG4 in HCC. We found that SNHG4 enhanced the proliferative, migratory and invasive capacities of HCC cell line, and facilitated the tumor growth in vivo. A series of follow-up studies have shown that SNHG4 promoted the progression and malignancy of HCC through upregulating CREB5 via sponging miR-211-5p. CONCLUSION: Collectively, the above findings suggest that SNHG4 promotes HCC malignancy through the SNHG4/miR-211-5p/CREB5 axis, providing potential therapeutic targets and prognostic factors for HCC. Highlights SNHG4 is overexpressed in HCC and correlated with the poor clinical characteristics SNHG4 promotes the malignant progression of HCC by reducing miR-211-5p expression MiR-211-5p inhibits CREB5 expression in HCC The oncogenic effect of SNHG4 in HCC can be reversed by CREB5 silencing.

microRNA-206 prevents hepatocellular carcinoma growth and metastasis via down-regulating CREB5 and inhibiting the PI3K/AKT signaling pathway.

Hepatocellular carcinoma (HCC) is one of the most common cancers and has continued to increase in incidence worldwide. Moreover, the involvement of microRNAs (miRs) has been reported in the development and progression of HCC. Here, we investigated the role of miR-206 in HCC growth and metastasis. HCC-related microarray datasets were harvested to screen differentially expressed miRNAs in HCC samples followed by prediction of downstream target genes. The dual-luciferase reporter assay verified the target-binding relationship between miR-206 and CREB5. The human HCC cell line MHCC97-H was cultured in vitro and transfected with miR-206 mimic/inhibitor or sh-/oe-CREB5 for analyzing MHCC97-H cell biological functions. The orthotopic xenograft model of HCC mice was constructed to observe the tumorigenic ability of HCC cells in vivo. Bioinformatics analysis found that miR-206 may be involved in HCC growth and metastasis by targeting CREB5 and regulating PI3K/AKT signaling pathway. In vivo animal experiments found that CREB5 was significantly overexpressed in mouse HCC tissues. In HCC cells, miR-206 can target down-regulate the expression of CREB5, thereby inhibiting the activation of PI3K/AKT signaling pathway. Furthermore, in vitro cell experiments confirmed that overexpression of miR-206 could inhibit the PI3K/AKT signaling pathway by down-regulating CREB5 expression, thereby inhibiting the proliferation, migration and invasion of HCC cells. In conclusion, our results revealed that miR-206 could down-regulate the expression of CREB5 and inhibit the activation of PI3K/AKT signaling pathway, thereby preventing HCC growth and metastasis.Abbreviations: HCC: hepatocellular carcinoma; HBV or HCV: hepatitis B or C virus; miRNAs: microRNAs; CREB: cAMP response element-binding protein; CRE: cAMP response elements.

A novel CREB5/TOP1MT axis confers cisplatin resistance through inhibiting mitochondrial apoptosis in head and neck squamous cell carcinoma.

BACKGROUND: Cisplatin resistance is one of the main causes of treatment failure and death in head and neck squamous cell carcinoma (HNSCC). A more comprehensive understanding of the cisplatin resistance mechanism and the development of effective treatment strategies are urgent. METHODS: RNA sequencing, RT-PCR, and immunoblotting were used to identify differentially expressed genes associated with cisplatin resistance. Gain- and loss-of-function experiments were performed to detect the effect of CREB5 on cisplatin resistance and mitochondrial apoptosis in HNSCC. Chromatin immunoprecipitation (ChIP) assay, dual-luciferase reporter assay, and immunoblotting experiments were performed to explore the underlying mechanisms of CREB5. RESULTS: CREB5 was significantly upregulated in cisplatin-resistant HNSCC (CR-HNSCC) patients, which was correlated with poor prognosis. CREB5 overexpression strikingly facilitated the cisplatin resistance of HNSCC cells in vitro and in vivo, while CREB5 knockdown enhanced cisplatin sensitivity in CR-HNSCC cells. Interestingly, the activation of AKT signaling induced by cisplatin promoted nucleus translocation of CREB5 in CR-HNSCC cells. Furthermore, CREB5 transcriptionally activated TOP1MT expression depending on the canonical motif. Moreover, CREB5 silencing could trigger mitochondrial apoptosis and overcome cisplatin resistance in CR-HNSCC cells, which could be reversed by TOP1MT overexpression. Additionally, double-targeting of CREB5 and TOP1MT could combat cisplatin resistance of HNSCC in vivo. CONCLUSIONS: Our findings reveal a novel CREB5/TOP1MT axis conferring cisplatin resistance in HNSCC, which provides a new basis to develop effective strategies for overcoming cisplatin resistance.

MicroRNA-204/CREB5 axis regulates vasculogenic mimicry in breast cancer cells.

BACKGROUND: Vasculogenic mimicry (VM) is characterized by formation of three-dimensional (3D) channels-like structures by tumor cells, supplying the nutrients needed for tumor growth. VM is stimulated by hypoxic tumor microenvironment, and it has been associated with increased metastasis and clinical poor outcome in cancer patients. cAMP responsive element (CRE)-binding protein 5 (CREB5) is a hypoxia-activated transcription factor involved in tumorigenesis. However, CREB5 functions in VM and if its regulated by microRNAs remains unknown in breast cancer. OBJECTIVE: We aim to study the functional relationships between VM, CREB5 and microRNA-204-5p (miR-204) in breast cancer cells. METHODS: CREB5 expression was evaluated by mining the public databases, and using RT-qPCR and Western blot assays. CREB5 expression was silenced using short-hairpin RNAs in MDA-MB-231 and MCF-7 breast cancer cells. VM formation was analyzed using matrigel-based cultures in hypoxic conditions. MiR-204 expression was restored in cancer cells by transfection of RNA mimics. Luciferase reporter assays were performed to evaluate the binding of miR-204 to 3'UTR of CREB5. RESULTS: Our data showed that CREB5 mRNA expression was upregulated in a set of breast cancer cell lines and clinical tumors, and it was positively associated with poor prognosis in lymph nodes positive and grade 3 basal breast cancer patients. Silencing of CREB5 impaired the hypoxia-induced formation of 3D channels-like structures representative of the early stages of VM in MDA-MB-231 cells. In contrast, VM formation was not observed in MCF-7 cells. Interestingly, we found that CREB5 expression was negatively regulated by miR-204 mimics in breast cancer cells. Functional analysis confirmed that miR-204 binds to CREB5 3'-UTR indicating that it's an ulterior effector. CONCLUSIONS: Our findings suggested that CREB5 could be a potential biomarker of disease progression in basal subtype of breast cancer, and that perturbations of the miR-204/CREB5 axis plays an important role in VM development in breast cancer cells.

Gene signatures and potential therapeutic targets of Middle East respiratory syndrome coronavirus (MERS-CoV)-infected human lung adenocarcinoma epithelial cells.

BACKGROUND: Pathogenic coronaviruses include Middle East respiratory syndrome coronavirus (MERS-CoV), severe acute respiratory syndrome coronavirus (SARS-CoV), and SARS-CoV-2. These viruses have induced outbreaks worldwide, and there are currently no effective medications against them. Therefore, there is an urgent need to develop potential drugs against coronaviruses. METHODS: High-throughput technology is widely used to explore differences in messenger (m)RNA and micro (mi)RNA expression profiles, especially to investigate protein-protein interactions and search for new therapeutic compounds. We integrated miRNA and mRNA expression profiles in MERS-CoV-infected cells and compared them to mock-infected controls from public databases. RESULTS: Through the bioinformatics analysis, there were 251 upregulated genes and eight highly differentiated miRNAs that overlapped in the two datasets. External validation verified that these genes had high expression in MERS-CoV-infected cells, including RC3H1, NF-κB, CD69, TNFAIP3, LEAP-2, DUSP10, CREB5, CXCL2, etc. We revealed that immune, olfactory or sensory system-related, and signal-transduction networks were discovered from upregulated mRNAs in MERS-CoV-infected cells. In total, 115 genes were predicted to be related to miRNAs, with the intersection of upregulated mRNAs and miRNA-targeting prediction genes such as TCF4, NR3C1, and POU2F2. Through the Connectivity Map (CMap) platform, we suggested potential compounds to use against MERS-CoV infection, including diethylcarbamazine, harpagoside, bumetanide, enalapril, and valproic acid. CONCLUSIONS: The present study illustrates the crucial roles of miRNA-mRNA interacting networks in MERS-CoV-infected cells. The genes we identified are potential targets for treating MERS-CoV infection; however, these could possibly be extended to other coronavirus infections.

Creb5 establishes the competence for Prg4 expression in articular cartilage.

A hallmark of cells comprising the superficial zone of articular cartilage is their expression of lubricin, encoded by the Prg4 gene, that lubricates the joint and protects against the development of arthritis. Here, we identify Creb5 as a transcription factor that is specifically expressed in superficial zone articular chondrocytes and is required for TGF-ß and EGFR signaling to induce Prg4 expression. Notably, forced expression of Creb5 in chondrocytes derived from the deep zone of the articular cartilage confers the competence for TGF-ß and EGFR signals to induce Prg4 expression. Chromatin-IP and ATAC-Seq analyses have revealed that Creb5 directly binds to two Prg4 promoter-proximal regulatory elements, that display an open chromatin conformation specifically in superficial zone articular chondrocytes; and which work in combination with a more distal regulatory element to drive induction of Prg4 by TGF-ß. Our results indicate that Creb5 is a critical regulator of Prg4/lubricin expression in the articular cartilage.

Image-based pooled whole-genome CRISPRi screening for subcellular phenotypes.

Genome-wide CRISPR screens have transformed our ability to systematically interrogate human gene function, but are currently limited to a subset of cellular phenotypes. We report a novel pooled screening approach for a wider range of cellular and subtle subcellular phenotypes. Machine learning and convolutional neural network models are trained on the subcellular phenotype to be queried. Genome-wide screening then utilizes cells stably expressing dCas9-KRAB (CRISPRi), photoactivatable fluorescent protein (PA-mCherry), and a lentiviral guide RNA (gRNA) pool. Cells are screened by using microscopy and classified by artificial intelligence (AI) algorithms, which precisely identify the genetically altered phenotype. Cells with the phenotype of interest are photoactivated and isolated via flow cytometry, and the gRNAs are identified by sequencing. A proof-of-concept screen accurately identified PINK1 as essential for Parkin recruitment to mitochondria. A genome-wide screen identified factors mediating TFEB relocation from the nucleus to the cytosol upon prolonged starvation. Twenty-one of the 64 hits called by the neural network model were independently validated, revealing new effectors of TFEB subcellular localization. This approach, AI-photoswitchable screening (AI-PS), offers a novel screening platform capable of classifying a broad range of mammalian subcellular morphologies, an approach largely unattainable with current methodologies at genome-wide scale.

CREB5 promotes invasiveness and metastasis in colorectal cancer by directly activating MET.

BACKGROUND: cAMP responsive element binding protein 5 (CREB5) is a transcriptional activator in eukaryotic cells that can regulate gene expression. Previously, we found that CREB5 was involved in the occurrence and development of colorectal cancer (CRC) using bioinformatics analysis. However, the biological roles and underlying regulatory mechanism of CREB5 in CRC remain unclear. METHODS: Real-time PCR, western blotting, and immunohistochemistry were used to examine CREB5 expression. In vitro experiments including migration assay, wound-healing assay, chicken chorioallantoic membrane assay, and human umbilical vein endothelial cells tube formation assay were used to investigate the effects of CREB5 on CRC cell migration and tumor angiogenesis ability. Additionally, an orthotopic implantation assay was performed in nude mice to confirm the effects of CREB5 in vivo. Furthermore, gene set enrichment analysis was performed to explore the potential mechanism of CREB5 in CRC. RESULTS: We found that CREB5 expression was highly upregulated in CRC. CREB5 overexpression was positively correlated with advanced WHO stages and TNM stages and shorter survival in CRC patients. Moreover, CREB5 overexpression promoted while CREB5 silencing reduced the invasiveness and metastatic capacity of CRC cells both in vitro and in vivo. Furthermore, CREB5 directly interacted with the MET promoter and activated the hepatocyte growth factor-MET signalling pathway. Importantly, inhibition of MET reduced the invasion and metastasis of CREB5-overexpressing CRC cells, suggesting that CREB5 promotes metastasis mainly through activation of MET signalling. CONCLUSION: Our study demonstrates a crucial role for CREB5 in CRC metastasis by directly upregulating MET expression. CREB5 may be both a potential prognostic marker and a therapeutic target to effectively overcome metastasis in CRC.

Sinapic acid induces the expression of thermogenic signature genes and lipolysis through activation of PKA/CREB signaling in brown adipocytes.

Lipid accumulation in white adipose tissue is the key contributor to the obesity and orchestrates numerous metabolic health problems such as type 2 diabetes, hypertension, atherosclerosis, and cancer. Nonetheless, the prevention and treatment of obesity are still inadequate. Recently, scientists found that brown adipose tissue (BAT) in adult humans has functions that are diametrically opposite to those of white adipose tissue and that BAT holds promise for a new strategy to counteract obesity. In this study, we evaluated the potential of sinapic acid (SA) to promote the thermogenic program and lipolysis in BAT. SA treatment of brown adipocytes induced the expression of brown-adipocyte activation-related genes such as Ucp1, Pgc-1α, and Prdm16. Furthermore, structural analysis and western blot revealed that SA upregulates protein kinase A (PKA) phosphorylation with competitive inhibition by a pan-PKA inhibitor, H89. SA binds to the adenosine triphosphate (ATP) site on the PKA catalytic subunit where H89 binds specifically. PKA-cat-α1 gene-silencing experiments confirmed that SA activates the thermogenic program via a mechanism involving PKA and cyclic AMP response element-binding protein (CREB) signaling. Moreover, SA treatment promoted lipolysis via a PKA/p38-mediated pathway. Our findings may allow us to open a new avenue of strategies against obesity and need further investigation. [BMB Reports 2020; 53(3): 142-147].

CREB5 Promotes Resistance to Androgen-Receptor Antagonists and Androgen Deprivation in Prostate Cancer.

Androgen-receptor (AR) inhibitors, including enzalutamide, are used for treatment of all metastatic castration-resistant prostate cancers (mCRPCs). However, some patients develop resistance or never respond. We find that the transcription factor CREB5 confers enzalutamide resistance in an open reading frame (ORF) expression screen and in tumor xenografts. CREB5 overexpression is essential for an enzalutamide-resistant patient-derived organoid. In AR-expressing prostate cancer cells, CREB5 interactions enhance AR activity at a subset of promoters and enhancers upon enzalutamide treatment, including MYC and genes involved in the cell cycle. In mCRPC, we found recurrent amplification and overexpression of CREB5. Our observations identify CREB5 as one mechanism that drives resistance to AR antagonists in prostate cancers.

LncRNA SNHG5 affects cell proliferation, metastasis and migration of colorectal cancer through regulating miR-132-3p/CREB5.

We aimed at the effects of long non-coding RNA (lncRNA) SNHG5 on proliferation, metastasis and migration of colorectal cancer (CRC) cells. We also investigated regulatory relationships among miR-132-3p, SNHG5 and CREB5 and their roles in CRC. 25 pairs of samples containing CRC tissues and matched para-tumor tissues were obtained to examine SNHG5, miR-132-3p and CREB5 expression by qRT-PCR or Western blot. The targeted relationship between miR-132-3p and SNHG5 or CREB5 was confirmed by dual luciferase report assay as well as RNA pull down assay. The expression of SNHG5, miR-132-3p and CREB5 in CRC cells were regulated by cell transfection. CRC cellular proliferation was assayed by CCK-8 and meanwhile flow cytometry was adopted to observe apoptosis. Metastasis and migration of CRC cells were determined respectively by means of Transwell assay and scratch test. The effects of SNHG5 on CRC were researched in vivo, too. SNHG5 or CREB5 was up-regulated in CRC tissues and cells, whereas miR-132-3p was down-regulated. Overexpression of SNHG5 and CREB5 resulted in the enhancement of proliferation, metastasis, migration and the inhibition of apoptosis in CRC cells, while miR-132-3p led to the opposite result. LncRNA SNHG5 promoted proliferation, migration and metastasis of CRC cells but inhibited apoptosis by modulating miR-132-3p/CERB5.

Integrated analysis of DNA methylome and transcriptome identified CREB5 as a novel risk gene contributing to recurrent pregnancy loss.

BACKGROUND: Aberrant DNA methylation is considered to be a potential cause of recurrent pregnancy loss (RPL), while potential mechanism has not yet been elucidated. METHODS: In order to uncover the contribution of the perturbation of DNA methylation in RPL, we performed genome-wide DNA methylation analysis combined with genome-wide gene expression in decidua tissue. FINDINGS: Totally, 539 differentially methylated regions (DMRs) were identified and significantly correlated with gene expressions. We observed that hypo-methylated DMR near CREB5 recruited transcription factors binding, such as P53 and SP1, and in turn upregulated CREB5. Compromised cell migration and apoptosis were observed in human CREB5 overexpression trophoblast cell lines, indicating dysfunctional trophoblast cells might contribute to RPL after hypo-methylation of CREB5. In addition, overexpression of CREB5 altered cell cycle. INTERPRETATION: Our data highlights a role of CREB5 involved in the pathogenesis of RPL, and CREB5 maybe a potential diagnostic biomarker for RPL.

Cellular senescence induces replication stress with almost no affect on DNA replication timing.

Organismal aging entails a gradual decline of normal physiological functions and a major contributor to this decline is withdrawal of the cell cycle, known as senescence. Senescence can result from telomere diminution leading to a finite number of population doublings, known as replicative senescence (RS), or from oncogene overexpression, as a protective mechanism against cancer. Senescence is associated with large-scale chromatin re-organization and changes in gene expression. Replication stress is a complex phenomenon, defined as the slowing or stalling of replication fork progression and/or DNA synthesis, which has serious implications for genome stability, and consequently in human diseases. Aberrant replication fork structures activate the replication stress response leading to the activation of dormant origins, which is thought to be a safeguard mechanism to complete DNA replication on time. However, the relationship between replicative stress and the changes in the spatiotemporal program of DNA replication in senescence progression remains unclear. Here, we studied the DNA replication program during senescence progression in proliferative and pre-senescent cells from donors of various ages by single DNA fiber combing of replicated DNA, origin mapping by sequencing short nascent strands and genome-wide profiling of replication timing (TRT). We demonstrate that, progression into RS leads to reduced replication fork rates and activation of dormant origins, which are the hallmarks of replication stress. However, with the exception of a delay in RT of the CREB5 gene in all pre-senescent cells, RT was globally unaffected by replication stress during entry into either oncogene-induced or RS. Consequently, we conclude that RT alterations associated with physiological and accelerated aging, do not result from senescence progression. Our results clarify the interplay between senescence, aging and replication programs and demonstrate that RT is largely resistant to replication stress.

Golgi Outpost Synthesis Impaired by Toxic Polyglutamine Proteins Contributes to Dendritic Pathology in Neurons.

Dendrite aberration is a common feature of neurodegenerative diseases caused by protein toxicity, but the underlying mechanisms remain largely elusive. Here, we show that nuclear polyglutamine (polyQ) toxicity resulted in defective terminal dendrite elongation accompanied by a loss of Golgi outposts (GOPs) and a decreased supply of plasma membrane (PM) in Drosophila class IV dendritic arborization (da) (C4 da) neurons. mRNA sequencing revealed that genes downregulated by polyQ proteins included many secretory pathway-related genes, including COPII genes regulating GOP synthesis. Transcription factor enrichment analysis identified CREB3L1/CrebA, which regulates COPII gene expression. CrebA overexpression in C4 da neurons restores the dysregulation of COPII genes, GOP synthesis, and PM supply. Chromatin immunoprecipitation (ChIP)-PCR revealed that CrebA expression is regulated by CREB-binding protein (CBP), which is sequestered by polyQ proteins. Furthermore, co-overexpression of CrebA and Rac1 synergistically restores the polyQ-induced dendrite pathology. Collectively, our results suggest that GOPs impaired by polyQ proteins contribute to dendrite pathology through the CBP-CrebA-COPII pathway.

Regulation of miRNA-29c and its downstream pathways in preneoplastic progression of triple-negative breast cancer.

Little is understood about the early molecular drivers of triple-negative breast cancer (TNBC), making the identification of women at risk and development of targeted therapy for prevention significant challenges. By sequencing a TNBC cell line-based breast cancer progression model we have found that miRNA-29c is progressively lost during TNBC tumorigenesis. In support of the tumor suppressive role of miRNA 29c, we found that low levels predict poor overall patient survival and, conversely, that ectopic expression of miRNA-29c in preneoplastic cell models inhibits growth. miRNA-29c exerts its growth inhibitory effects through direct binding and regulation of TGFB-induced factor homeobox 2 (TGIF2), CAMP-responsive element binding protein 5 (CREB5), and V-Akt murine thymoma viral oncogene homolog 3 (AKT3). miRNA-29c regulation of these gene targets seems to be functionally relevant, as TGIF2, CREB5, and AKT3 were able to rescue the inhibition of cell proliferation and colony formation caused by ectopic expression of miRNA-29c in preneoplastic cells. AKT3 is an oncogene of known relevance in breast cancer, and as a proof of principle we show that inhibition of phosphoinositide 3-kinase (PI3K) activity, a protein upstream of AKT3, suppressed proliferation in TNBC preneoplastic cells. We explored additional opportunities for prevention of TNBC by studying the regulation of miRNA-29c and identified DNA methylation to have a role in the inhibition of miRNA-29c during TNBC tumorigenesis. Consistent with these observations, we found 5 aza-cytadine to relieve the suppression of miRNA-29c. Together, these results demonstrate that miRNA-29c loss plays a key role in the early development of TNBC.

Epigenetically regulated miR-449a enhances hepatitis B virus replication by targeting cAMP-responsive element binding protein 5 and modulating hepatocytes phenotype.

Cellular microRNAs (miRNAs) are able to influence hepatitis B virus (HBV) replication directly by binding to HBV transcripts or indirectly by targeting cellular factors. Here, we investigate the effect of epigenetically regulated miR-449a on HBV replication and the underlying mechanisms. miR-449a expression was lower in human hepatocellular carcinoma (HCC) cells than in primary hepatocytes and could be induced by trichostatin A. Ectopic miR-449a expression in HCC cells strongly enhanced HBV replication, transcription, progeny virions secretion, and antigen expression in a dose-dependent manner. miR-449a directly targeted cAMP-responsive element binding protein 5 (CREB5), which in turn induced the expression of farnesoid X receptor α (FXRα), a transcription factor that facilitates HBV replication. CREB5 knockdown and overexpression demonstrated that it is a negative regulator of HBV replication. Additionally, miR-449a overexpression inhibited proliferation, caused cell cycle arrest, and promoted HCC cell differentiation. The results indicated that epigenetically regulated miR-449a targets CREB5 to increase FXRα expression, thereby promoting HBV replication and gene expression. Our findings provide a new understanding of the role of miRNAs in HBV replication.

MiR-582-5p/miR-590-5p targeted CREB1/CREB5-NF-κB signaling and caused opioid-induced immunosuppression in human monocytes.

Chronic opioid abusers are more susceptible to bacterial and viral infections, but the molecular mechanism underlying opioid-induced immunosuppression is unknown. MicroRNAs (miRNAs) are emerging as key players in the control of biological processes, and may participate in immune regulation. In this study, we investigated the molecular mechanisms in opioid-induced and miRNA-mediated immunosuppression, in the context of miRNA dysregulation in opioid abusers. Blood samples of heroin abusers were collected and analyzed using miRNA microarray analysis and quantitative PCR validation. The purified primary human monocytes were cultured in vitro to explore the underlying mechanism. We found that morphine and its derivative heroin significantly decreased the expression levels of miR-582-5p and miR-590-5p in monocytes. cAMP response element-binding protein 1 (CREB1) and CREB5 were detected as direct target genes of miR-582-5p and miR-590-5p, respectively, by using dual-luciferase assay and western bolt. Functional studies showed that knockdown of CREB1/CREB5 increased tumor necrosis factor alpha (TNF-α) level and enhanced expression of phospho-NF-κB p65 and NF-κB p65. Our results demonstrated that miR-582-5p and miR-590-5p play important roles in opioid-induced immunosuppression in monocytes by targeting CREB1/CREB5-NF-κB signaling pathway.

Involvement of the CREB5 regulatory network in colorectal cancer metastasis.

The signal regulatory network involved in colorectal cancer metastasis is complicated and thus the search for key control steps in the network is of great significance for unraveling colorectal cancer metastasis mechanism and finding drug-target site. Previous studies suggested that CREB5 (cAMP responsive element binding protein 5) might play key role in the metastatic signal network of colorectal cancer. Through colorectal cancer expression profile and enriching analysis of the effect of CREB5 gene expression levels on colorectal cancer molecular events, we found that these molecular events are correlated with tumor metastasis. Based on the feature that CREB5 could combine with c-Jun to form heterodimer, together with enriched binding sites for transcription factor AP-1, we identified 16 genes which were up-regulated in the CREB5 high-expression group, contained AP-1 binding sites, and participated in cancer pathway. The molecular network involving these 16 genes, in particular, CSF1R, MMP9, PDGFRB, FIGF and IL6, regulates cell migration. Therefore, CREB5 might accelerate the metastasis of colorectal cancer by regulating these five key genes.

How genome-wide SNP-SNP interactions relate to nasopharyngeal carcinoma susceptibility.

This study is the first to use genome-wide association study (GWAS) data to evaluate the multidimensional genetic architecture underlying nasopharyngeal cancer. Since analysis of data from GWAS confirms a close and consistent association between elevated risk for nasopharyngeal carcinoma (NPC) and major histocompatibility complex class 1 genes, our goal here was to explore lesser effects of gene-gene interactions. We conducted an exhaustive genome-wide analysis of GWAS data of NPC, revealing two-locus interactions occurring between single nucleotide polymorphisms (SNPs), and identified a number of suggestive interaction loci which were missed by traditional GWAS analyses. Although none of the interaction pairs we identified passed the genome-wide Bonferroni-adjusted threshold for significance, using independent GWAS data from the same population (Stage 2), we selected 66 SNP pairs in 39 clusters with P<0.01. We identified that in several chromosome regions, multiple suggestive interactions group to form a block-like signal, effectively reducing the rate of false discovery. The strongest cluster of interactions involved the CREB5 gene and a SNP rs1607979 on chromosome 17q22 (P = 9.86×10(-11)) which also show trans-expression quantitative loci (eQTL) association in Chinese population. We then detected a complicated cis-interaction pattern around the NPC-associated HLA-B locus, which is immediately adjacent to copy-number variations implicated in male susceptibility for NPC. While it remains to be seen exactly how and to what degree SNP-SNP interactions such as these affect susceptibility for nasopharyngeal cancer, future research on these questions holds great promise for increasing our understanding of this disease's genetic etiology, and possibly also that of other gene-related cancers.

IMPDH2 genetic polymorphism: a promoter single-nucleotide polymorphism disrupts a cyclic adenosine monophosphate responsive element.

Inosine 5'-monophosphate dehydrogenase (IMPDH), which catalyzes a key step in the de novo biosynthesis of guanine nucleotide, is mediated by two highly conserved isoforms, IMPDH1 and IMPDH2. In this study, IMPDH2 genetic polymorphism was investigated in 96 individuals of Caucasian origin. Four single-nucleotide polymorphisms were identified, comprising one previously described single base-pair substitution in the close vicinity of the consensus donor splice site of intron 7 (IVS7+10T>C), and three novel polymorphisms, one silent substitution in exon 9 (c.915C>G), one single base-pair insertion (g.6971_6972insT) within the 3'-untranslated region of the gene, and one substitution located in the promoter region (c.-95T>G) in a transcription factor binding site CRE(A) (cyclic adenosine monophosphate [cAMP] response element). Considering the nature and location of this latter polymorphism, its functional relevance was examined by transfecting HEK293 and Jurkat cell lines with constructs of the related region of IMPDH2/luciferase reporter gene. The c.-95T>G mutation leads to a significant decrease of luciferase activity (HEK293: 55% decrease, p < 0.05; Jurkat: 65% decrease, p < 0.05) compared with the wild-type promoter sequence and, therefore, is likely to determine interindividual differences in IMPDH2 transcriptional regulation. These results might contribute to a better understanding of the variability in clinical outcome and dose adjustments of certain immunosuppressors that are metabolized through the IMPDH pathway or that are IMPDH inhibitors.