E2F transcription factor 5, a new regulator in adipogenesis to mediate the role of Krüppel-like factor 7 in chicken preadipocyte differentiation and proliferation.

E2F transcription factor 5 (E2F5) gene is a transcription factor, plays an important role in the development of a variety of cells. E2F5 is expressed in human and mouse adipocytes, but its specific function in adipogenesis is unclear. Krüppel-like factor 7 (KLF7) facilitates proliferation and inhibits differentiation in chicken preadipocytes. Our previous KLF7 chromatin immunoprecipitation-sequencing analysis revealed a KLF7-binding peak in the 3' flanking region of the E2F5, indicating a regulatory role of KLF7 in this region. In the present study, we investigated E2F5 potential role, the overexpression and knockdown analyses revealed that E2F5 inhibited the differentiation and promoted the proliferation of chicken preadipocytes. Moreover, we identified enhancer activity in the 3' flanking region (nucleotides +22661/+22900) of E2F5 and found that KLF7 overexpression increased E2F5 expression and luciferase activity in this region. Deleting the putative KLF7-binding site eliminated the promoting effect of KLF7 overexpression on E2F5 expression. Further, E2F5 reversed the KLF7-induced decrease in preadipocyte differentiation and increase in preadipocyte proliferation. Taken together, our findings demonstrate that KLF7 inhibits differentiation and promotes proliferation in preadipocytes by enhancing E2F5 transcription.

Knockdown of RNA-binding protein IMP3 suppresses oral squamous cell carcinoma proliferation by destabilizing E2F5 transcript.

The expression level of RNA-binding proteins (RBPs) is dysregulated in oral squamous cell carcinoma (OSCC) and other types of cancer. Among the RBPs, IMP3 is involved in the progression of OSCC. However, the regulation of mRNA fate by IMP3 in OSCC remains less understood. We analyzed the expression level of IMP3 and E2F5 in OSCC tissues and cell lines by immunohistochemistry, qRT-PCR and Western blot. Subsequently, to further investigate the effect of IMP3 on E2F5 expression, we used siRNAs to silence IMP3 expression in OSCC cell lines SCC-25 and SCC-4. The binding site of E2F5 mRNA and IMP3 was confirmed by RNA immunoprecipitation (RIP). Finally, the function of IMP3 and E2F5 was investigated in viro and in xenograft mouse models. Here we report a positive correlation between IMP3 and E2F5 expression in OSCC, which are involved in cell proliferation and cell cycle. Mechanistically, E2F5 mRNA is bound by IMP3 protein, and silencing it leads to a shortened mRNA half-life and reduced protein expression. Also, knockdown of IMP3 inhibited allograft tumor progression in vivo. These studies reveal the molecular mechanism by which IMP3 regulates E2F5 mRNA stability and identify IMP3/E2F5 as a potential therapeutic target in OSCC.

E2F5 Targeted by Let-7d-5p Facilitates Cell Proliferation, Metastasis and Immune Escape in Gallbladder Cancer.

BACKGROUND: Gallbladder cancer (GBC) remains a serious cause of cancer-related mortality across the globe. E2F5 has been identified to as a known oncogene in various cancers. However, the special functions of E2F5 have not been investigated in GBC. AIMS: To explore the regulatory functions of E2F5 and its related molecular regulatory mechanism in GBC progression. METHODS: The expression of genes were examined through qRT-PCR, western blot and IHC assay. The cell proliferation was assessed through CCK-8 and EDU assays. The cytotoxicity was tested through LDH assay. The percentage of CD8+ T cells and cell apoptosis were evaluated through flow cytometry. The binding ability was detected through luciferase reporter assay. The tumor growth was assessed through in vivo assays. RESULTS: In this study, it was demonstrated that E2F5 expression was evaluated in GBC, and resulted into poor prognosis. Bioinformatics analysis revealed E2F5 as a target for let-7d-5p, which when overexpressed, suppressed the metastasis and proliferation of GBC through the downregulation of E2F5. It was discovered that E2F5 activates JAK2/STAT3 signaling which is suppressed by let-7d-5p, implicating this pathway as one of the effectors of the oncogenic effects of ESF5 in GBC. E2F5 had been confirmed to aggravate tumor growth in vivo. CONCLUSION: E2F5 targeted by let-7d-5p facilitated cell proliferation, metastasis and immune escape in GBC through the JAK2/STAT3 pathway.

LINC01980 induced by TGF-beta promotes hepatocellular carcinoma metastasis via miR-376b-5p/E2F5 axis.

Hepatocellular carcinoma (HCC) is one of the most aggressive human malignancies worldwide. However, the molecular mechanism of HCC metastasis is largely unknown. Long non-coding RNA (lncRNA) plays a key role in gene regulation, and dysregulation of lncRNA is critical to cancer metastasis. LINC01980 has been reported in ESCC recently, but the mechanism underlying its function in HCC is still unknown. In this study, we found that LINC01980 was upregulated and associated with notably poor overall survival in HCC patients. Functionally, LINC01980 played a carcinogenic role and promoted HCC metastasis. Mechanically, LINC01980 enhanced the E2F5 expression via competitively binding miR-376b-5p, thereby inducing epithelial-mesenchymal transition and promoting HCC cells migration and invasion. In addition, LINC01980-mediated HCC cells metastasis was dependent on E2F5. What's more, TGF-ß activated LINC01980 transcription through the canonical TGF-ß/SMAD signaling pathway in HCC. In conclusion, LINC01980, activated by the canonical TGF-ß/SMAD pathway, promoted HCC metastasis via miR-376b-5p/E2F5 axis. Therefore, LINC01980 might be a potential prognostic biomarker and therapeutic target of HCC.

MAPK Is a Mutual Pathway Targeted by Anxiety-Related miRNAs, and E2F5 Is a Putative Target for Anxiolytic miRNAs.

Anxiety-related disorders (ARDs) are chronic neuropsychological diseases and the sixth leading cause of disability in the world. As dysregulation of microRNAs (miRs) are observed in the pathological course of neuropsychiatric disorders, the present study aimed to introduce miRs that underlie anxiety processing in the brain. First, we collected the experimentally confirmed anxiety-related miRNAs (ARmiRs), predicted their target transcripts, and introduced critical cellular pathways with key commune hub genes. As a result, we have found nine anxiolytic and ten anxiogenic ARmiRs. The anxiolytic miRs frequently target the mRNA of Acyl-CoA synthetase long-chain family member 4 (Acsl4), AFF4-AF4/FMR2 family member 4 (Aff4), and Krüppel like transcription factor 4 (Klf4) genes, where miR-34b-5p and miR-34c-5p interact with all of them. Moreover, the anxiogenic miRs frequently target the mRNA of nine genes; among them, only two miR (miR-142-5p and miR-218-5p) have no interaction with the mRNA of trinucleotide repeat-containing adaptor 6B (Tnrc6b), and miR-124-3p interacts with all of them where MAPK is the main signaling pathway affected by both anxiolytic and anxiogenic miR. In addition, the anxiolytic miR commonly target E2F transcription factor 5 (E2F5) in the TGF-ß signaling pathway, and the anxiogenic miR commonly target Ataxin 1 (Atxn1), WASP-like actin nucleation promoting factor (Wasl), and Solute Carrier Family 17 Member 6 (Slc17a6) genes in the notch signaling, adherence junction, and synaptic vesicle cycle pathways, respectively. Taken together, we conclude that the most important anxiolytic (miR-34c, Let-7d, and miR-17) and anxiogenic (miR-19b, miR-92a, and 218) miR, as hub epigenetic modulators, potentially influence the pathophysiology of anxiety, primarily via interaction with the MAPK signaling pathway. Moreover, the role of E2F5 as a novel putative target for anxiolytic miRNAs in ARDs disorders deserves further exploration.

E2F5 promotes proliferation and invasion of gastric cancer through directly upregulating UBE2T transcription.

The underlying mechanisms of E2F5 upregulation and its pro-tumor functions have not been elucidated in gastric cancer (GC). Here, the expression, prognostic value, mutation status, and promoter methylation of E2F5 were evaluated. The effects of E2F5 depletion on cell proliferation and invasion in GC, were also assessed through in vitro experiments. Additionally, gene set enrichment analysis (GSEA) was applied to analyze the potential downstream regulator of E2F5. The study also assessed the correlation and transcription regulation between E2F5 and UBE2T. Finally, the roles of UBE2T in E2F5-related pro-tumor functions were examined. The findings revealed that E2F5 was upregulated and showed remarkable association with pathological variables and prognosis. Hypomethylation of the E2F5 promoter predicted poor prognosis and partially caused E2F5 upregulation in GC. E2F5 knockdown significantly inhibited the proliferation and invasion of GC cells. E2F5 had a significant positive correlation with UBE2T in GC. Mechanistically, E2F5 promoted UBE2T transcription and UBE2T overexpression reversed the effects of E2F5 depletion on the proliferation and invasion of cells in GC. Taken together, this study originally confirmed the upregulation of E2F5 in GC, revealed that E2F5 can directly upregulate UBE2T transcription, and subsequently promote the malignant progression, which highlights that the E2F5/UBE2T axis can potentially be used in the diagnosis and treatment of GC.

E2F5 Promotes the Malignancy of Ovarian Cancer Via the Regulation of Hippo and Wnt Pathways.

Background: E2F5 is a transcription factor that is overexpressed in the early stages of ovarian cancer and has been suggested as a potential biomarker for early detection. In this study, we aimed to examine the role of E2F5 in invasion and proliferation of ovarian cancer cells. Materials and Methods: We performed cell viability, colony formation, and invasion assays using ovarian cancer cells treated with siRNA to knock down the E2F5 gene. The regulatory effects of E2F5 on proteins involved in the apoptotic, Wnt, Hippo, and retinoblastoma signaling pathways were evaluated by western blotting following E2F5 repression. In addition, we analyzed data available on Gene Expression Profiling Interactive Analysis for correlations between E2F5 and YAP, ß-catenin, cyclin D1, cdk4, and caspase-9. Results: E2F5 was highly expressed in ovarian cancer cell lines and samples when compared to the nonmalignant tissues. Downregulation of E2F5 inhibited cell viability and invasion and promoted the phosphorylation of YAP, GSK-3-ß, ß-catenin, and retinoblastoma. However, cyclin D1, cdk4, and caspase-9 were downregulated when compared to control. Conclusion: Overall, E2F5 promotes ovarian carcinogenesis via the regulation of Hippo and Wnt pathways.

Downregulation of long non-coding RNA UCA1 represses tumorigenesis and metastasis of osteosarcoma via miR-513b-5p/E2F5 axis.

Long non-coding RNAs have the regulatory roles in different kinds of human cancers. The key point of this study was to research the functional mechanisms of urothelial carcinoma associated 1 (UCA1) in the development of osteosarcoma. Quantitative real-time PCR was adopted for the expression detection of UCA1, microRNA-513b-5p (miR-513b-5p) and E2F transcription factor 5 (E2F5). The target relation was verified via dual-luciferase reporter assay and RNA pull-down assay. Cell proliferation was evaluated using Cell Counting Kit-8 and colony formation assays. Transwell assay was applied to assess cell migration and invasion. Western blot was performed for protein examination. Xenograft experiment was used to explore the effect of UCA1 on osteosarcoma in vivo. UCA1 expression was enhanced while miR-513b-5p was refrained in osteosarcoma tissues and cells. MiR-513b-5p was a target of UCA1. Inhibition of UCA1 or overexpression of miR-513b-5p suppressed osteosarcoma cell proliferation, migration and invasion. E2F5 was identified as a downstream gene of miR-513b-5p. MiR-513b-5p inhibitor or E2F5 overexpression rescued the progression inhibition of osteosarcoma by UCA1 knockdown, and UCA1 regulated E2F5 and Cyclin E expression by targeting miR-513b-5p. Downregulation of UCA1 restrained the tumorigenesis of osteosarcoma in vivo through the miR-513b-5p/E2F5 axis. Collectively, knockdown of UCA1 inhibited tumorigenesis and metastasis of osteosarcoma via regulating the miR-513b-5p/E2F5 axis. UCA1 might be a biological indicator in the progression and treatment of osteosarcoma.

CDK13 upregulation-induced formation of the positive feedback loop among circCDK13, miR-212-5p/miR-449a and E2F5 contributes to prostate carcinogenesis.

BACKGROUND: Both E2F transcription factor and cyclin-dependent kinases (CDKs), which increase or decrease E2F activity by phosphorylating E2F or its partner, are involved in the control of cell proliferation, and some circRNAs and miRNAs regulate the expression of E2F and CDKs. However, little is known about whether dysregulation among E2Fs, CDKs, circRNAs and miRNAs occurs in human PCa. METHODS: The expression levels of CDK13 in PCa tissues and different cell lines were determined by quantitative real-time PCR and Western blot analysis. In vitro and in vivo assays were preformed to explore the biological effects of CDK13 in PCa cells. Co-immunoprecipitation anlysis coupled with mass spectrometry was used to identify E2F5 interaction with CDK13. A CRISPR-Cas9 complex was used to activate endogenous CDK13 and circCDK13 expression. Furthermore, the mechanism of circCDK13 was investigated by using loss-of-function and gain-of-function assays in vitro and in vivo. RESULTS: Here we show that CDK13 is significantly upregulated in human PCa tissues. CDK13 depletion and overexpression in PCa cells decrease and increase, respectively, cell proliferation, and the pro-proliferation effect of CDK13 is strengthened by its interaction with E2F5. Mechanistically, transcriptional activation of endogenous CDK13, but not the forced expression of CDK13 by its expression vector, remarkably promotes E2F5 protein expression by facilitating circCDK13 formation. Further, the upregulation of E2F5 enhances CDK13 transcription and promotes circCDK13 biogenesis, which in turn sponges miR-212-5p/449a and thus relieves their repression of the E2F5 expression, subsequently leading to the upregulation of E2F5 expression and PCa cell proliferation. CONCLUSIONS: These findings suggest that CDK13 upregulation-induced formation of the positive feedback loop among circCDK13, miR-212-5p/miR-449a and E2F5 is responsible for PCa development. Targeting this newly identified regulatory axis may provide therapeutic benefit against PCa progression and drug resistance.

Knockdown of E2F5 induces cell death via the TP53­dependent pathway in breast cancer cells carrying wild­type TP53.

E2F transcription factor 5 (E2F5) is a member of the E2F family of transcription factors, which are involved in regulation of various cellular processes, including cellular proliferation, apoptosis, differentiation and DNA damage response. Previously, we reported that E2F5 was aberrantly overexpressed in estrogen receptor (ER)­negative breast cancer, especially in triple­negative breast cancer (TNBC). In the present study, it was revealed that E2F5 gene silencing caused a significant reduction in the proliferation rate of breast cancer MCF7 (ER­positive luminal­type) and MDA­MB­231 (TNBC­type) cells. Additional experiments demonstrated that E2F5 knockdown triggered cell death of MCF7 cells but not MDA­MB­231 cells. As MCF7 and MDA­MB­231 cells carry wild­type and mutant TP53, respectively, and BT474 (ER­negative, HER2­positive type) carrying mutant TP53 exhibited similar results to MDA­MB­231, the possible effects of E2F5 gene depletion on cell death­related TP53­target gene expression were examined. Real­time RT­qPCR analysis revealed that knockdown of E2F5 in MCF7 cells stimulated cell death­related transcription of TP53­target genes such as BAX, NOXA and PUMA. For MDA­MB­231 and BT474 cells, E2F5 gene silencing revealed marginal effects on the expression of TP53 target genes. In addition, silencing of TP53 abrogated the effect of E2F5 silencing in MCF7 cells. Collectively, the present results indicated that E2F5 participated in the carcinogenesis of breast cancer carrying wild­type TP53 through suppression of TP53, while E2F5 had a pro­proliferative but not anti­apoptotic effect on breast cancer with TP53 mutation.

Circular RNA ABCB10 promotes non-small cell lung cancer progression by increasing E2F5 expression through sponging miR-584-5p.

BACKGROUND/AIMS: CircABCB10 function as an endogenous miRNA sponge plays an important role in various tumors. This experimental design was based on circABCB10 to explore the pathogenesis of non-small cell lung cancer (NSCLC). Methods: CircRNA microarray was used to examine circRNA expression profiles in lung cancer from 3 NSCLC patients and paired healthy lung tissues. The expression of circABCB10 and miR-584-5p was detected by q-PCR. CCK-8, colony formation, and transwell assays to study the circABCB10 effects on tumor cell growth and cell migration invasiveness. To validate downstream target genes of circABCB10 and miR-584-5p detected by luciferase reporter assays. RT-qPCR and Western blotting were used to study E2F5 expression. The tumor growth was detected by nude mice in vivo. Results: We analyzed the human circRNA expression profile in NSCLC tissues. CircABCB10 was identified as a circRNA that increased in NSCLC tissues. CircABCB10 was noticeably raised in NSCLC, and high circABCB10 expression was related to low survival in NSCLC patients. Silencing of circABCB10 suppressed non-small cell lung cancer cell migration, cell proliferation, and invasion.CircABCB10 can act as a sponge of miR-584-5p to up-regulate E2F5 expression level. E2F5 knockdown or overexpress of miR-584-5p gene reversed the circABCB10 who has carcinogenic effects. There was a negative correlation expression between the circABCB10 and miR-584-5p gene, and There was a positive relationship between the expression of circABCB10 and E2F5 in NSCLC tumors. Conclusion: CircABCB10 promoted the progression of NSCLC by modulating the miR-584-5p/E2F5 axis. ABBREVIATION: NSCLC: non-small cell lung cancer; circ RNA: circular RNA; miRNA: micro RNA.

FAT4 silencing promotes epithelial-to-mesenchymal transition and invasion via regulation of YAP and ß-catenin activity in ovarian cancer.

BACKGROUND: The adhesion molecule, FAT4, has a tumor suppressor function with a critical role in the epithelial-to-mesenchymal-transition (EMT) and anti-malignant growth in several cancers. No study has investigated yet its role in epithelial ovarian cancer (EOC) progression. In the present study, we examined the role of FAT4 in proliferation and metastasis, and its mechanisms of interaction in these processes. METHODS: We have performed cell viability, colony formation, and invasion assays in ovarian cancer cells treated with siRNA to knockdown FAT4 gene expression. The regulatory effects of FAT4 on proteins involved in apoptotic, Wnt, Hippo, and retinoblastoma signaling pathways were evaluated by Western blotting following FAT4 repression. Also, 426 ovarian tumor samples and 88 non-tumor samples from the Gene Expression Profiling Interactive Analysis (GEPIA) database were analyzed for the expression of FAT4. Pearson's correlation was performed to determine the correlation between FAT4 and the E2F5, cyclin D1, cdk4, and caspase 9 expressions. RESULTS: Lower expression of FAT4 was observed in ovarian cancer cell lines and human samples as compared to non-malignant tissues. This down-regulation seems to enhance cell viability, invasion, and colony formation. Silencing FAT4 resulted in the upregulation of E2F5, vimentin, YAP, ß-catenin, cyclin D1, cdk4, and Bcl2, and in the downregulation of GSK-3-ß, and caspase 9 when compared to control. Furthermore, regulatory effects of FAT4 on the EMT and aggressive phenotype seem to occur through Hippo, Wnt, and cell cycle pathways. CONCLUSION: FAT4 downregulation promotes increased growth and invasion through the activation of Hippo and Wnt-ß-catenin pathways.

E2F5 promotes prostate cancer cell migration and invasion through regulation of TFPI2, MMP-2 and MMP-9.

Previously, our laboratory demonstrated that a deregulated E2F5/p38/SMAD3 axis was associated with uncontrolled cellular proliferation in prostate cancer (PCa). Here, we investigate the role of E2F5 in PCa in further details. RNAi-mediated E2F5 knockdown and pathway-focused gene expression profiling in PC3 cells identified TFPI2 as a downstream target of E2F5. Manipulation of E2F5 expression was also found to alter MMP-2 and MMP-9 levels as detected by Proteome Profiler array, western blot and reverse transcription coupled quantitative polymerase chain reaction Site-directed mutagenesis, dual-luciferase assays and chromatin immunoprecipitation with anti-E2F5-IgG coupled with qPCR confirmed recruitment of E2F5 on TFPI2, MMP-2 and MMP-9 promoters. RNAi-mediated knockdown of E2F5 expression in PC3 caused a significant alteration of cell migration while that of TFFI2 resulted in a modest change. Abrogation of E2F5 and TFPI2 expression was associated with significant changes in the gelatinolytic activity of active forms of MMP-2 and MMP-9. Moreover, E2F5, MMP-2 and MMP-9 levels were elevated in biopsies of PCa patients relative to that of benign hyperplasia, while TFPI2 expression was reduced. MMP-9 was coimmunoprecipitated with anti-TFPI2-IgG in PCa tissue samples suggesting a direct interaction between the proteins. Finally, artemisinin treatment in PC3 cells repressed E2F5 along with MMP-2/MMP-9 while triggering TFPI2 expression which alleviated PC3 aggressiveness possibly through inhibition of MMP activities. Together, our study reinstates an oncogenic role of E2F5 which operates as a dual-function transcription factor for its targets TFPI2, MMP-2 and MMP-9 and promotes cellular invasiveness. This study also indicates a therapeutic potential of artemisinin, a natural compound which acts by correcting dysfunctional E2F5/TFPI2/MMP axis in PCa.

E2f5 is a versatile transcriptional activator required for spermatogenesis and multiciliated cell differentiation in zebrafish.

E2f5 is a member of the E2f family of transcription factors that play essential roles during many cellular processes. E2f5 was initially characterized as a transcriptional repressor in cell proliferation studies through its interaction with the Retinoblastoma (Rb) protein for inhibition of target gene transcription. However, the precise roles of E2f5 during embryonic and post-embryonic development remain incompletely investigated. Here, we report that zebrafish E2f5 plays critical roles during spermatogenesis and multiciliated cell (MCC) differentiation. Zebrafish e2f5 mutants develop exclusively as infertile males. In the mutants, spermatogenesis is arrested at the zygotene stage due to homologous recombination (HR) defects, which finally leads to germ cell apoptosis. Inhibition of cell apoptosis in e2f5;tp53 double mutants rescued ovarian development, although oocytes generated from the double mutants were still abnormal, characterized by aberrant distribution of nucleoli. Using transcriptome analysis, we identified dmc1, which encodes an essential meiotic recombination protein, as the major target gene of E2f5 during spermatogenesis. E2f5 can bind to the promoter of dmc1 to promote HR, and overexpression of dmc1 significantly increased the fertilization rate of e2f5 mutant males. Besides gametogenesis defects, e2f5 mutants failed to develop MCCs in the nose and pronephric ducts during early embryonic stages, but these cells recovered later due to redundancy with E2f4. Moreover, we demonstrate that ion transporting principal cells in the pronephric ducts, which remain intercalated with the MCCs, do not contain motile cilia in wild-type embryos, while they generate single motile cilia in the absence of E2f5 activity. In line with this, we further show that E2f5 activates the Notch pathway gene jagged2b (jag2b) to inhibit the acquisition of MCC fate as well as motile cilia differentiation by the neighboring principal cells. Taken together, our data suggest that E2f5 can function as a versatile transcriptional activator and identify novel roles of the protein in spermatogenesis as well as MCC differentiation during zebrafish development.

MicroRNA­34a inhibits esophageal squamous cell carcinoma progression by targeting E2F5.

PURPOSE: Previous studies have explored the role of microRNA-34a (miR-34a) and E2F transcription family in several tumors, however, the expression level and oncogenesis mechanism of these two factors in esophageal squamous cancer cells (ESCC) remains unclear. Our study aims to explore the inhibitory effect of miR-34a in ESCC as well as its downstream factor E2F5. METHODS: We explored the relevant expression level of miR-34a in human tumor tissue as well as in several ESCC cell lines. Through RNA mimic and inhibitor, we examined the specific role of miR-34a in the proliferation, apoptosis and migration of tumor cells, and we further explored the role of downstream factor E2F5 through gain- and loss-of-function analyses. RESULTS: We found that the expression level of miR-34a is significantly downregulated in ESCC tissues as well as in ESCC cell lines, and miR-34a plays an inhibitory role in tumor cell proliferation and migration while it promotes tumor cell apoptosis. We further showed that E2F5 is a direct functional target of miR-34a, as it promotes tumor cell proliferation and migration and inhibits apoptosis. CONCLUSIONS: Our results indicate that the intrinsic expression of miR-34a was relatively low in ESCC. The anti-tumor effect of miR-34a is possibly dependent on the regulation of cell-cycle regulator E2F5.

Distinct requirements of E2f4 versus E2f5 activity for multiciliated cell development in the zebrafish embryo.

Multiciliated cells (MCCs) differentiate arrays of motile cilia that beat to drive fluid flow over epithelia. Recent studies have established two Geminin family coiled-coil containing nuclear regulatory proteins, Gmnc and Multicilin (Mci), in the specification and differentiation of the MCCs. Both Gmnc and Mci are devoid of a DNA binding domain: they regulate transcription by associating with E2f family transcription factors, notably E2f4 and E2f5. Here, we have studied the relative contribution of these two E2f factors in MCC development using the zebrafish embryo, which differentiates MCCs within kidney tubules and the nose. We found that while E2f4 is fully dispensable, E2f5 is essential for MCCs to form in the kidney tubules. Moreover, using a variety of double mutant combinations we show that E2f5 has a more prominent role in MCC development in the zebrafish than E2f4. This contrasts with current evidence from the mouse, where E2f4 seems to be more important. Thus, distinct combinatorial activities of the E2f4 and E2f5 proteins regulate the specification and differentiation of MCCs in zebrafish and mice.

MicroRNA-1179 inhibits the proliferation, migration and invasion of human pancreatic cancer cells by targeting E2F5.

Pancreatic cancer is one of deadly cancers and is responsible for significant mortality and morbidity across the globe. The unavailability of the efficient chemotheruptic drugs and the potent thereuprtic targets forms a bottleneck in the treatment of pancreatic cancer. In this study we explored the potential of MicroRNA-1179 as the therapeutic target for the treatment of pancreatic cancer. The results of this study indicated that the expression of miR-1179 was significantly downregulated in the pancreatic cancer cell lines as compared to the normal pancreatic cells. To unveil the potential role of miR-1179, it was overexpressed in the pancreatic cancer cells. It was observed that ectopic expression of miR-1179 caused reduction in the proliferation of pancreatic cancer cells by triggering G0/G1 cell cycle arrest. Further, overexpression of miR-1179 caused inhibition of the cell migration and invasion of the pancreatic cancer cells. To find out the potential target of miR-1179 in pancreatic cancer cells, we carried out bioinformatic analysis, the results showed that miR-1179 targets E2F transcription factor 5. This was also confirmed by western blotting analysis wherein in overexpression of miR-1179 was associated with the downregulation of the expression E2F5. Conversely, silencing of E2F5 had similar effects as that of miR-1179 suppression. Further, E2F5 overexpression could also nullify the effect on cell proliferation, migration and invasion in pancreatic cancer cells. Finally, miR-1179 overexpression could also inhibit tumor growth in vivo by suppressing the expression of E2F5. Taken together, we conclude that miR-1179 overexpression may prove beneficial for the treatment of pancreatic cancer.

Let-7c Inhibits the Proliferation, Invasion, and Migration of Glioma Cells via Targeting E2F5.

As a member of the miRNA family, let-7c has been identified as a tumor suppressor in many cancers. However, the molecular biological function of let-7c in glioma has not been elucidated. The aim of this study was to explore let-7c expression levels and evaluate its function in glioma cells. We first measured the expression of let-7c in four glioma cell lines and a normal cell line by quantitative real-time reverse transcription polymerase chain reaction (qRT-PCR), and the results showed that let-7c was downregulated in glioma cells. By applying gain-of-function and loss-of-function assays, the experiments suggested that dysregulation of let-7c could obviously affect cell proliferation, metastasis, and invasion. Based on online bioinformatics analysis and Dual-Luciferase Reporter assays, we found that E2F5 was a target gene of let-7c and contributed to the function of let-7c in glioma cells. Our investigations indicated that loss of let-7c contributed to the progression of glioma cells.

Controlling centriole numbers: Geminin family members as master regulators of centriole amplification and multiciliogenesis.

To ensure that the genetic material is accurately passed down to daughter cells during mitosis, dividing cells must duplicate their chromosomes and centrosomes once and only once per cell cycle. The same key steps-licensing, duplication, and segregation-control both the chromosome and the centrosome cycle, which must occur in concert to safeguard genome integrity. Aberrations in genome content or centrosome numbers lead to genomic instability and are linked to tumorigenesis. Such aberrations, however, can also be part of the normal life cycle of specific cell types. Multiciliated cells best exemplify the deviation from a normal centrosome cycle. They are post-mitotic cells which massively amplify their centrioles, bypassing the rule for once-per-cell-cycle centriole duplication. Hundreds of centrioles dock to the apical cell surface and generate motile cilia, whose concerted movement ensures fluid flow across epithelia. The early steps that control the generation of multiciliated cells have lately started to be elucidated. Geminin and the vertebrate-specific GemC1 and McIdas are distantly related coiled-coil proteins, initially identified as cell cycle regulators associated with the chromosome cycle. Geminin is required to ensure once-per-cell-cycle genome replication, while McIdas and GemC1 bind to Geminin and are implicated in DNA replication control. Recent findings highlight Geminin family members as early regulators of multiciliogenesis. GemC1 and McIdas specify the multiciliate cell fate by forming complexes with the E2F4/5 transcription factors to switch on a gene expression program leading to centriole amplification and cilia formation. Positive and negative interactions among Geminin family members may link cell cycle control to centriole amplification and multiciliogenesis, acting close to the point of transition from proliferation to differentiation. We review key steps of centrosome duplication and amplification, present the role of Geminin family members in the centrosome and chromosome cycle, and discuss links with disease.