E2A predicts prognosis of colorectal cancer patients and regulates cancer cell growth by targeting miR-320a

Targeting TNF/IL-17/MAPK pathway in hE2A-PBX1 leukemia: effects of OUL35, KJ-Pyr-9, and CID44216842

t(1;19)(q23;p13) is one of the most common translocation genes in childhood acute lymphoblastic leukemia (ALL) and is also present in acute myeloid leukemia (AML) and mixed-phenotype acute leukemia (MPAL). This translocation results in the formation of the oncogenic E2A-PBX1 fusion protein, which contains a trans-activating domain from E2A and a DNA-binding homologous domain from PBX1. Despite its clear oncogenic potential, the pathogenesis of E2A-PBX1 fusion protein is not fully understood (especially in leukemias other than ALL), and effective targeted clinical therapies have not been developed. To address this, we established a stable and heritable zebrafish line expressing human E2A-PBX1 (hE2A-PBX1) for high-throughput drug screening. Blood phenotype analysis showed that hE2A-PBX1 expression induced myeloid hyperplasia by increasing myeloid differentiation propensity of hematopoietic stem cells (HSPC) and myeloid proliferation in larvae, and progressed to AML in adults. Mechanistic studies revealed that hE2A-PBX1 activated the TNF/IL-17/MAPK signaling pathway in blood cells and induced myeloid hyperplasia by upregulating the expression of runx1. Interestingly, through high-throughput drug screening, three small molecules targeting the TNF/IL-17/MAPK signaling pathway were identified, including OUL35, KJ-Pyr-9, and CID44216842, which not only alleviated the hE2A-PBX1-induced myeloid hyperplasia in zebrafish but also inhibited the growth and oncogenicity of human pre-B ALL cells with E2A-PBX1. Overall, this study provides a novel hE2APBX1 transgenic zebrafish leukemia model and identifies potential targeted therapeutic drugs, which may offer new insights into the treatment of E2A-PBX1 leukemia.

Expression Profiles of ID and E2A in Ovarian Cancer and Suppression of Ovarian Cancer by the E2A Isoform E47

The E2A and inhibitor of DNA binding (ID) proteins are transcription factors involved in cell cycle regulation and cellular differentiation. Imbalance of ID/E2A activity is associated with oncogenesis in various tumors, but their expression patterns and prognostic values are still unknown. We evaluated ID and E2A expression in ovarian cancer cells, and assessed the possibility of reprogramming ovarian cellular homeostasis by restoring the ID/E2A axis. We analyzed copy number alterations, mutations, methylations, and mRNA expressions of ID 1-4 and E2A using The Cancer Genome Atlas data of 570 ovarian serous cystadenocarcinoma patients. Incidentally, 97.2% cases exhibited gain of ID 1-4 or loss of E2A. Predominantly, ID 1-4 were hypomethylated, while E2A was hypermethylated. Immunohistochemical analysis revealed that ID-3 and ID-4 expressions were high while E2A expression was low in cancerous ovarian tissues. Correlation analysis of ID and E2A levels with survival outcomes of ovarian cancer patients indicated that patients with high ID-3 levels had poor overall survival. We also determined the effect of E2A induction on ovarian cancer cell growth in vitro and in vivo using SKOV-3/Luc cells transduced with tamoxifen-inducible E47, a splice variant of E2A. Interestingly, E47 induced SKOV-3 cell death in vitro and inhibited tumor growth in SKOV-3 implanted mice. Therefore, restoring ID/E2A balance is a promising approach for treating ovarian cancer.

TCF3 protein was highly expressed in pediatric Burkitt lymphoma and predicts poor prognosis: a single-center study

This retrospective single-center study was to evaluate the expression of TCF3 protein in pediatric Burkitt lymphomas (pBLs) and analyze its relations with clinical characteristics and prognosis. A total of 58 pBLs and 30 reactive hyperplastic lymphadenites (RH) were recruited. The high expression rate of TCF3 was 67.24% in pBLs, significantly higher than that in the RHs (36.67%, p = .01), which was consistent with the findings in biopsy specimens from mRNA and protein level, respectively. The expression of TCF3 was significantly associated with tumor localization and size. A total of 54 patients having received short-intensive chemotherapy had a median follow-up of 54.15 months (range: 1-111 months). Log-rank test of Kaplan-Meier survival curves indicated an inverse correlation of TCF3 expression with the overall survival (OS) and event-free survival (EFS). Univariate analysis showed that high TCF3 expression was significantly associated with poor EFS. The result of multivariate COX regression analysis indicated that the TCF3 expression was an independent prognostic factor for EFS.

MEX3D is an oncogenic driver in prostate cancer

BACKGROUND

Prostate cancer (PCa) is the most common visceral malignancy and the second leading cause of cancer deaths in US men. The two most common genetic alterations in PCa are expression of the TMPRSS2/ERG (TE) fusion gene and loss of the PTEN tumor suppressor. These genetic alterations act cooperatively to transform prostatic epithelium but the exact mechanisms involved are unclear.

METHODS

Microarray expression analysis of immortalized prostate epithelial cells transformed by loss of PTEN and expression of the TE fusion revealed MEX3D as one of the most highly upregulated genes. MEX3D expression in prostate cancer was examined in patient samples and in silico. In vitro and in vivo studies to characterize the biological impact of MEX3D were carried out. Analysis of the TCGA PanCancer database revealed TCF3 as a major target of MEX3D. The induction of TCF3 by MEX3D was confirmed and the biological impact of TCF3 examined by in vitro studies.

RESULTS

MEX3D is expressed at increased levels in prostate cancer and is increased by decreased PTEN and/or expression of the TE fusion gene and drives soft agar colony formation, invasion and tumor formation in vivo. The known oncogenic transcription factor TCF3 is highly correlated with MEX3D in prostate cancer. MEX3D expression strongly induces TCF3, which promotes soft agar colony formation and invasion in vitro.

CONCLUSIONS

Loss of PTEN and expression of the TE fusion gene in prostate cancer strongly upregulates expression of MEX3D and its target TCF3 and promotes transformation associated phenotypes via this pathway.

MicroRNA 320, an Anti-Oncogene Target miRNA for Cancer Therapy

MicroRNAs are a set of highly conserved non-coding RNAs that control gene expression at the post-transcriptional/translational levels by binding to the 3′-UTR of diverse target genes. Increasing evidence indicates that miRNAs not only play a vital role in many biological processes, but they are also frequently deregulated in pathological conditions, including cancer. The miR-320 family is one of many tumor suppressor families and is composed of five members, which has been demonstrated to be related to the repression of epithelial-mesenchymal transition (EMT) inhibition, cell proliferation, and apoptosis. Moreover, this family has been shown to regulate drug resistance, and act as a potential biomarker for the diagnosis, prognosis, and prediction of cancer. In this review, we summarized recent research with reference to the tumor suppressor function of miR-320 and the regulation mechanisms of miR-320 expression. The collected evidence shown here supports that miR-320 may act as a novel biomarker for cancer prognosis and therapeutic response to cancer treatment.

MicroRNA as a Prognostic and Diagnostic Marker in T-Cell Acute Lymphoblastic Leukemia

T cell acute lymphoblastic leukemia (T-ALL) is a biologically and genetically heterogeneous disease with a poor prognosis overall and several subtypes. The neoplastic transformation takes place through the accumulation of numerous genetic and epigenetic abnormalities. There are only a few prognostic factors in comparison to B cell precursor acute lymphoblastic leukemia, which is characterized by a lower variability and more homogeneous course. The microarray and next-generation sequencing (NGS) technologies exploring the coding and non-coding part of the genome allow us to reveal the complexity of the genomic and transcriptomic background of T-ALL. miRNAs are a class of non-coding RNAs that are involved in the regulation of cellular functions: cell proliferations, apoptosis, migrations, and many other processes. No miRNA has become a significant prognostic and diagnostic factor in T-ALL to date; therefore, this topic of investigation is extremely important, and T-ALL is the subject of intensive research among scientists. The altered expression of many genes in T-ALL might also be caused by wide miRNA dysregulation. The following review focuses on summarizing and characterizing the microRNAs of pediatric patients with T-ALL diagnosis and their potential future use as predictive factors.

Circulating miR-320a Acts as a Tumor Suppressor and Prognostic Factor in Non-small Cell Lung Cancer

Dysregulated expression profiles of microRNAs (miRNAs) have been observed in several types of cancer, including non-small cell lung cancer (NSCLC); however, the diagnostic and prognostic potential of circulating miRNAs in NSCLC remains largely undefined. Here we found that circulating miR-320a was significantly down-regulated (~5.87-fold; p < 0.0001) in NSCLC patients (n = 80) compared to matched control plasma samples from healthy subjects (n = 80). Kaplan-Meier survival analysis revealed that NSCLC patients with lower levels of circulating miR-320a had overall poorer prognosis and survival rates compared to patients with higher levels (p < 0.0001). Moreover, the diagnostic and prognostic potential of miR-320a correlated with clinicopathological characteristics such as tumor size, tumor node metastasis (TNM) stage, and lymph node metastasis. Functionally, depletion of miR-320a in human A549 lung adenocarcinoma cells induced their metastatic potential and reduced apoptosis, which was reversed by exogenous re-expression of miR-320a mimics, indicating that miR-320a has a tumor-suppressive role in NSCLC. These results were further supported by high levels of epithelial-mesenchymal transition (EMT) marker proteins (e.g., Beta-catenin, MMP9, and E-cadherin) in lung cancer cells and tissues via immunoblot and immunohistochemistry experiments. Moreover, through bioinformatics and dual-luciferase reporter assays, we demonstrated that AKT3 was a direct target of miR-320a. In addition, AKT3-associated PI3K/AKT/mTOR protein-signaling pathways were elevated with down-regulated miR-320a levels in NSCLC. These composite data indicate that circulating miR-320a may function as a tumor-suppressor miRNA with potential as a prognostic marker for NSCLC patients.

E2A attenuates tumor-initiating capacity of colorectal cancer cells via the Wnt/beta-catenin pathway

BACKGROUND

The E2A gene, which encodes two basic helix-loop-helix transcription factors, E12 and E47, regulates colorectal cancer progression and epithelial-mesenchymal transition. However, whether E2A regulates the tumor-initiating capacity of colorectal cancer is unclear. Thus, we have studied E2A expression in the initiation of colorectal cancer in vivo and in vitro.

METHODS

Immunohistochemistry and immunoblot were performed to determine protein levels of E2A in colorectal cancer specimens and cells. RNAi was employed to downregulate E2A expression, and the subsequent change in protein level was evaluated by immunoblot. Sphere-forming assay and enumeration of liver metastasis in mouse models were used to identify the tumor formation ability of colorectal cancer cells.

RESULTS

E2A expression in colorectal cancer clinical specimens was inversely associated with patients' progression-free survival. Functional studies demonstrated that E2A significantly decreased tumor formation in vitro and in vivo. Furthermore, nuclear translocation of beta-catenin and activation of the Wnt/beta-catenin pathway occurred after suppression of E2A in colorectal cancer cells. FoxM1 was identified as a down-stream target by mRNA microarray, implying that FoxM1 plays a main role in determining how E2A regulates the tumor-initiating capacity of colorectal cancer.

CONCLUSION

E2A suppresses tumor-initiating capacity by targeting the FoxM1-Wnt/β-catenin pathway.

MiR-320a-3p/ELF3 axis regulates cell metastasis and invasion in non-small cell lung cancer via PI3K/Akt pathway

MicroRNAs (miRNAs) play important roles in tumorigenesis and tumor progression. In this study, we investigated the role of miR-320a-3p in non-small cell lung cancer (NSCLC). Expressions of miR-320a-3p were firstly determined in 80 NSCLC patients' cancer tissues and adjacent normal lung tissues by qRT-PCR. Then MTT assay, cell migration and invasion assays were performed in vitro. Potential binding sites on target gene of miR-320a-3p were predicted and luciferase reporter assay was used to identify the potential binding sites. Tumorigenesis assay were performed in nude mice by injecting A549 cells which stably express miR-320a-3p. Results indicated that high expression of miR-320a-3p suppresses cell proliferation, migration and invasion through the inactivation of PI3K/Akt signaling pathway in NSCLC cells. Smaller tumor size and lighter weight were also found in nude mice which had miR-320a-3p higher expressed. Furthermore, data from luciferase reporter assay proved the direct binding of miR-320a-3p on the 3'UTR region of ELF3 mRNA, this could further decrease ELF3 expression transcriptionally. We provided evidence that miR-320a-3p might work as a tumor suppressor in NSCLC both in vivo and in vitro.

Hypoxic regulation of MYBL1, MEST, TCF3, TCF8, GTF2B, GTF2F2 and SNAI2 genes expression in U87 glioma cells upon IRE1 inhibition

We investigated the impact of IRE1/ERN1 (inositol requiring enzyme 1/endoplasmic reticulum to nucleus signaling 1) knockdown on hypoxic regulation of the expression of a subset of proliferation and migration-related genes in U87 glioma cells. It was shown that hypoxia leads to up-regulation of the expression of MEST and SNAI2, to down-regulation – of MYBL1, TCF8 and GTF2F2 genes at the mRNA level in control glioma cells. At the same time hypoxia did not affect the expression of TCF3 and GTF2B transcription factor genes. In turn, inhibition of IRE1 modified the effect of hypoxia on the expression of all studied genes, except MYBL1 and GTF2B. For instance, IRE1 knockdown decreased sensitivity to hypoxia of the expression of MEST, TCF8 and SNAI2 genes and increased sensitivity to hypoxia of GTF2F2 expression. At the same time, IRE1 inhibition introduced sensitivity to hypoxia of the expression of TCF3 gene in glioma cells. The present study demonstrated that the inhibition of IRE1 in glioma cells affected the hypoxic regulation of the expression of studied genes in various directions, though hypoxic conditions did not abolish the effect of IRE1 inhibition on the expression of respective genes. To the contrary, in case of SNAI2, GTF2F2 and MEST hypoxic conditions magnified the effect of IRE1 inhibition on the expression of respective genes in glioma cells.

Expression of E2A in mid-secretory endometrium of women suffering from recurrent miscarriage

E2A is involved in promoting forkhead box P3 (FOXP3) and retinoid-related orphan receptor gamma t (RORγt) gene transcription, which are pivotal transcription factors of T regulatory cells and Th17 cells, respectively. Little is known about the involvement of E2A in pregnancy process. This study aimed to investigate the expression of E2A, cytotoxic T-lymphocyte-associated protein 4 (CTLA-4), and Foxp3 in luteal phase endometrium of women suffering recurrent miscarriage (RM) (n=21) and control group (n=11) by immunohistochemistry, with the Vectra® automated quantitative pathology imaging system for analysis. The percentage of E2A+ cells and CTLA-4+ cells was significantly higher in the endometrium of women with RM than in the controls. There was positive correlation between E2A and CTLA-4 (r=0.523, P=0.002), E2A and FOXP3 (r=0.380, P=0.032), and FOXP3 and CTLA-4 (r=0.625, P=0.000) in the mid-secretory phase of endometrium for all subjects. It was concluded that the abnormal expression of endometrial E2A existed in mid-secretory endometrium of women with RM, and there was a positive correlation between E2A and FOXP3, and E2A and CTLA-4, suggesting the possible regulation role of E2A involved in regulating endometrium receptivity.

Identification of cancer prognosis-associated functional modules using differential co-expression networks

The rapid accumulation of cancer-related data owing to high-throughput technologies has provided unprecedented choices to understand the progression of cancer and discover functional networks in multiple cancers. Establishment of co-expression networks will help us to discover the systemic properties of carcinogenesis features and regulatory mechanisms of multiple cancers. Here, we proposed a computational workflow to identify differentially co-expressed gene modules across 8 cancer types by using combined gene differential expression analysis methods and a higher-order generalized singular value decomposition. Four co-expression modules were identified; and oncogenes and tumor suppressors were significantly enriched in these modules. Functional enrichment analysis demonstrated the significantly enriched pathways in these modules, including ECM-receptor interaction, focal adhesion and PI3K-Akt signaling pathway. The top-ranked miRNAs (mir-199, mir-29, mir-200) and transcription factors (FOXO4, E2A, NFAT, and MAZ) were identified, which play an important role in deregulating cellular energetics; and regulating angiogenesis and cancer immune system. The clinical significance of the co-expressed gene clusters was assessed by evaluating their predictability of cancer patients’ survival. The predictive power of different clusters and subclusters was demonstrated. Our results will be valuable in cancer-related gene function annotation and for the evaluation of cancer patients’ prognosis.

miR-320a regulates high mobility group box 1 expression and inhibits invasion and metastasis in hepatocellular carcinoma

BACKGROUND & AIMS

Several studies have shown that miR-320a induces apoptosis, inhibits cell proliferation, and affects cell cycle progression as a tumour suppressor in many cancers. However, the involvement of miR-320a in the invasion and metastasis of hepatocellular carcinoma (HCC) is still unknown.

METHODS

Endogenous miR-320a and high mobility group box 1 (HMGB1) expressions were assayed by real-time PCR. Luciferase activities were measured using a dual-luciferase reporter assay system. Western blots were used to determine the protein expressions of HMGB1, MMP2, and MMP9. Invasion and metastasis of tumour cells were, respectively, evaluated by the transwell invasion assay and the wound healing assay.

RESULTS

The expression of miR-320a was significantly decreased in 24 of 32 (75%) HCC tissues and associated with the invasion and metastasis of HCC. Furthermore, we demonstrated that HMGB1 was a direct target of miR-320a and there was a significant negative correlation between miR-320a and HMGB1 expression in HCC. Ectopic expression or inhibition of miR-320a potently regulated the invasion and metastasis of HCC cells in HMGB1-dependent manner.

CONCLUSIONS

Our results showed that miR-320a was involved in the invasion and metastasis by targeting HMGB1 and had an anti-metastasis effect in HCC.

Up-regulation of Transcription Factor 3 Is Correlated With Poor Prognosis in Cervical Carcinoma

OBJECTIVES

Transcription factor 3 (TCF3, or E2A) is a multifunctional bHLH (basic helix loop helix) transcription factor. The role of TCF3 expression in cancer and the multiple cell signaling pathways that regulate or are influenced by TCF3 are unclear. Therefore, the expression level of TCF3 in patients with cervical squamous cell carcinoma (CSCC) is discussed in this study.

METHODS

Total RNA was extracted using real-time quantitative reverse transcription-polymerase chain reaction. Western blotting was applied to confirm the results. Immunohistochemistry was used to characterize the expression patterns of TCF3 in CSCC specimens. The close relationship between the expression levels of TCF3 and the 5-year overall survival time was described by survival curves. The association between TCF3 expression and clinicopathological characteristics of 119 CSCC patients was analyzed by Chi-square, Fisher exact test, and Cox regression analysis. TCF3 was overexpressed or inhibited by plasmid transfection, and the proliferation, invasion, and migration of cells were detected using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT), wound healing, and Transwell assays.

RESULTS

The expression of TCF3 was higher in CSCC tissues than in nonmalignant cervical tissues. Messenger RNA (mRNA) and protein in patient tissues were increased compared with nonmalignant cervical tissues. Moreover, the level of expression in early-stage disease was higher than in the advanced stage. From FIGO (International Federation of Gynecology and Obstetrics) stages I to IV, immunohistochemistry staining intensity gradually increased. A high level of expression was closely related to clinical stages. The expression of TCF3 was negatively correlated with overall survival time. TCF3 can promote HeLa cell growth, invasion, and migration in vitro.

CONCLUSIONS

Based on our results, TCF3 is clearly associated with the progression of CSCC. This is the first time that it has been reported that TCF3 can act as a tumor promoter in cervical cancer and thus might be of great significance in the prognosis of CSCC.

The increased expression of TCF3 is correlated with poor prognosis in Chinese patients with nasopharyngeal carcinoma

OBJECTIVES

Regulatory factors controlling stem cell identity and self-renewal are often active in aggressive cancers and are thought to promote cancer growth and progression. B-cell-specific transcription factor 3 (TCF3/E2A) is a member of the T-cell factor/lymphoid enhancer factor (TCF/LEF) transcription factor family that is central to regulating epidermal and embryonic stem cell identity. It has been reported that TCF3 was connected with the development and progression of a number of human cancers. In this study, we aimed to identify the expression of TCF3 in human nasopharyngeal carcinoma (NPC) and evaluate its clinical significance.

DESIGN

To investigate the expression of TCF3 in NPC and its relationship to prognosis.

SETTING

An in vitro study.

MAIN OUTCOME MEASURES

We analysed the expression of TCF3 in NPC and in non-tumourous nasopharyngeal tissues by quantitative RT-PCR and Western blotting. The expression patterns of TCF3 in 117 archived paraffin-embedded NPC specimens were characterised by immunohistochemistry, and the correlation between the TCF3 protein expression and the clinicopathological features of NPC was analysed.

RESULTS

We observed that TCF3 had a higher expression in NPC than in non-tumourous nasopharyngeal tissues of 117 archived paraffin-embedded NPC specimens, and 80 (68.4%) biopsy tissues revealed high levels of TCF3 expression. Furthermore, statistical analyses demonstrated that the increased expression of TCF3 was closely related to clinical stage, locoregional recurrence and distant metastasis of NPC. NPC patients with high levels of TCF3 expression had a shorter survival time, whereas patients with lower levels of TCF3 expression survived longer. Moreover, multivariate analysis suggested that the upregulation of TCF3 was a critical prognostic factor for NPC.

CONCLUSIONS

Our observations suggest, for the first time, that TCF3 is significantly associated with the development and progression of NPC, which can be used as an important prognostic marker for patients with NPC and may be an effective target for the treatment of NPC.

miR-320a regulates cell proliferation and apoptosis in multiple myeloma by targeting pre-B-cell leukemia transcription factor 3

Aberrant expression of microRNAs (miRNAs) is implicated in cancer development and progression. While miR-320a is reported to be deregulated in many malignancy types, its biological role in multiple myeloma (MM) remains unclear. Here, we observed reduced expression of miR-320a in MM samples and cell lines. Ectopic expression of miR-320a dramatically suppressed cell viability and clonogenicity and induced apoptosis in vitro. Mechanistic investigation led to the identification of Pre-B-cellleukemia transcription factor 3 (PBX3) as a novel and direct downstream target of miR-320a. Interestingly, reintroduction of PBX3 abrogated miR-320a-induced MM cell growth inhibition and apoptosis. In a mouse xenograft model, miR-320a overexpression inhibited tumorigenicity and promoted apoptosis. Our findings collectively indicate that miR-320a inhibits cell proliferation and induces apoptosis in MM cells by directly targeting PBX3, supporting its utility as a novel and potential therapeutic agent for miRNA-based MM therapy.

Understanding the CREB1-miRNA feedback loop in human malignancies

cAMP response element binding protein 1 (CREB1, CREB) is a key transcription factor that mediates transcriptional responses to a variety of growth factors and stress signals. CREB1 has been shown to play a critical role in development and progression of tumors. MicroRNAs (miRNAs) are a class of non-coding RNAs. They post-transcriptionally regulate gene expression through pairing with the 3'-UTR of their target mRNAs and thus regulate initiation and progression of various types of human cancers. Recent studies have demonstrated that a number of miRNAs can be transcriptionally regulated by CREB1. Interestingly, CREB1 expression can also be modulated by miRNAs, thus forming a feedback loop. This review outlines the functional roles of CREB1, miRNA, and their interactions in human malignancies. This will help to define a relationship between CREB1 and miRNA in human cancer and develop novel therapeutic strategies.

Basic helix loop helix (bHLH) transcription factor 3 (TCF3, E2A) is regulated by androgens in prostate cancer cells

TCF3 (E2A) is a multifunctional basic helix loop helix (bHLH) transcription factor that is over-expressed in prostate cancer (PCa) as compared to normal prostate and that it acts as a tumor promoter in PCa. Given the diverse biological pathways regulated/influenced by TCF3, little is known about the mechanisms that regulate its expression. TCF3 expression in androgen sensitive LNCaP and insensitive C81 PCa cell lines was determined following treatments with androgen receptor (AR) agonist R1881 and antagonist Casodex. In silico analysis was used to discover putative Androgen Response Elements (ARE) in the TCF3 promoter/intron region. Chromatin Immunoprecipitation (ChIP) with AR antibody and luciferase reporter assays on the above mentioned cell lines was used to confirm AR biding and AR dependent transcriptional activity respectively. The results were confirmed by demonstrating TCF3 expression in LNCaP PCa xenograft models. The results suggested that TCF3 transcript increased in response to R1881 in LNCaP cells but was constitutively expressed in C-81 cell lines. The promoter/Intron region of the TCF3 gene was predicted to contain two putative ARE sites ARE1 and ARE2. ChIP after treatment of LNCaP and C81 cells with R1881 and Casodex showed that the ARE1 and ARE2 were bound by AR in LNCaP cells only in the presence of R1881, whereas C81 cells showed constitutive AR binding. Similar results were observed in luciferase reporter assays indicating that TCF3 is activated by AR in LNCaP cell lines whereas it is independent of androgens in C81 cell line. Luciferase reporter assays also confirmed that ARE1 alone drives androgen dependent transcription. TCF3 expression was only observed in castration resistant LNCaP xenografts in castrated mice. In conclusion, we demonstrate that in PCa androgen receptor regulates the expression of TCF3 which is mediated in part via a consensus androgen response element. The shift in TCF3 expression from androgen regulated to androgen independent during prostate cancer progression, together with lack of expression in normal prostate may provide mechanistic basis underlying the transition of androgen receptor from a tumor suppressor to an oncogene in prostate cancer.

Cross Platform Standardisation of an Experimental Pipeline for Use in the Identification of Dysregulated Human Circulating MiRNAs

Introduction

Micro RNAs (miRNAs) are a class of highly conserved small non-coding RNAs that play an important part in the post-transcriptional regulation of gene expression. A substantial number of miRNAs have been proposed as biomarkers for diseases. While reverse transcriptase Real-time PCR (RT-qPCR) is considered the gold standard for the evaluation and validation of miRNA biomarkers, small RNA sequencing is now routinely being adopted for the identification of dysregulated miRNAs. However, in many cases where putative miRNA biomarkers are identified using small RNA sequencing, they are not substantiated when RT-qPCR is used for validation. To date, there is a lack of consensus regarding optimal methodologies for miRNA detection, quantification and standardisation when different platform technologies are used.

Materials and Methods

In this study we present an experimental pipeline that takes into consideration sample collection, processing, enrichment, and the subsequent comparative analysis of circulating small ribonucleic acids using small RNA sequencing and RT-qPCR.

Results, Discussion, Conclusions

Initially, a panel of miRNAs dysregulated in circulating blood from breast cancer patients compared to healthy women were identified using small RNA sequencing. MiR-320a was identified as the most dysregulated miRNA between the two female cohorts. Total RNA and enriched small RNA populations (<30 bp) isolated from peripheral blood from the same female cohort samples were then tested for using a miR-320a RT-qPCR assay. When total RNA was analysed with this miR-320a RT-qPCR assay, a 2.3-fold decrease in expression levels was observed between blood samples from healthy controls and breast cancer patients. However, upon enrichment for the small RNA population and subsequent analysis of miR-320a using RT-qPCR, its dysregulation in breast cancer patients was more pronounced with an 8.89-fold decrease in miR-320a expression. We propose that the experimental pipeline outlined could serve as a robust approach for the identification and validation of small RNA biomarkers for disease.

Transcription factor hlh-2/E/Daughterless drives expression of α integrin ina-1 during DTC migration in C. elegans

Integrins are involved in a vast number of cell behaviors due to their roles in adhesion and signaling. The regulation of integrin expression is of particular interest as a mechanism to drive developmental events and for the role of altered integrin expression profiles in cancer. Dynamic regulation of the expression of integrin receptors is required for the migration of the distal tip cell (DTC) during gonadogenesis in Caenorhabditis elegans. α integrin ina-1 is required for DTC motility, yet is up-regulated by an unknown mechanism. Analysis of the promoter for α integrin ina-1 identified two E-box sequences that are required for ina-1 expression in the DTC. Knockdown of transcription factor hlh-2, an established E-box binding partner and ortholog of E/Daughterless, prevented expression of a transcriptional fusion of the ina-1 promoter to RFP and blocked DTC migration. Similarly, knockdown of hlh-2 also prevented expression of a translational fusion of the genomic ina-1 gene to GFP while blocking DTC migration. Knockdown of HLH-2 binding partner MIG-24 also reduced ina-1 expression and DTC migration. Overall, these results show that the transcription factor hlh-2 is required for up-regulation of ina-1 at the onset of DTC migration.