Deficiency in trefoil factor 1 (TFF1) increases tumorigenicity of human breast cancer cells and mammary tumor development in TFF1-knockout mice

Therapeutical potential of deregulated lysine methyltransferase SMYD3 as a safe target for novel anticancer agents

INTRODUCTION

SET and MYND domain containing-3 (SMYD3) is a member of the lysine methyltransferase family of proteins, and plays an important role in the methylation of various histone and non-histone targets. Proper functioning of SMYD3 is very important for the target molecules to determine their different roles in chromatin remodeling, signal transduction and cell cycle control. Due to the abnormal expression of SMYD3 in tumors, it is projected as a prognostic marker in various solid cancers. Areas covered: Here we elaborate on the general information, structure and the pathological role of SMYD3 protein. We summarize the role of SMYD3-mediated protein interactions in oncology pathways, mutational effects and regulation of SMYD3 in specific types of cancer. The efficacy and mechanisms of action of currently available SMYD3 small molecule inhibitors are also addressed. Expert opinion: The findings analyzed herein demonstrate that aberrant levels of SMYD3 protein exert tumorigenic effects by altering the epigenetic regulation of target genes. The partial involvement of SMYD3 in some distinct pathways provides a vital opportunity in targeting cancer effectively with fewer side effects. Further, identification and co-targeting of synergistic oncogenic pathways is suggested, which could provide much more beneficial effects for the treatment of solid cancers.

An integrative and comparative study of pan-cancer transcriptomes reveals distinct cancer common and specific signatures

To investigate the commonalities and specificities across tumor lineages, we perform a systematic pan-cancer transcriptomic study across 6744 specimens. We find six pan-cancer subnetwork signatures which relate to cell cycle, immune response, Sp1 regulation, collagen, muscle system and angiogenesis. Moreover, four pan-cancer subnetwork signatures demonstrate strong prognostic potential. We also characterize 16 cancer type-specific subnetwork signatures which show diverse implications to somatic mutations, somatic copy number aberrations, DNA methylation alterations and clinical outcomes. Furthermore, some of them are strongly correlated with histological or molecular subtypes, indicating their implications with tumor heterogeneity. In summary, we systematically explore the pan-cancer common and cancer type-specific gene subnetwork signatures across multiple cancers, and reveal distinct commonalities and specificities among cancers at transcriptomic level.

Integration of Breast Cancer Secretomes with Clinical Data Elucidates Potential Serum Markers for Disease Detection, Diagnosis, and Prognosis

Cancer cells secrete factors that influence adjacent cell behavior and can lead to enhanced proliferation and metastasis. To better understand the role of these factors in oncogenesis and disease progression, estrogen and progesterone receptor positive MCF-7 cells, triple negative breast cancer MDA-MB-231, DT22, and DT28 cells, and MCF-10A non-transformed mammary epithelial cells were grown in 3D cultures. A special emphasis was placed on triple negative breast cancer since these tumors are highly aggressive and no targeted treatments are currently available. The breast cancer cells secreted factors of variable potency that stimulated proliferation of the relatively quiescent MCF-10A cells. The conditioned medium from each cell line was subjected to mass spectrometry analysis and a variety of secreted proteins were identified including glycolytic enzymes, proteases, protease inhibitors, extracellular matrix proteins, and insulin-like growth factor binding proteins. An investigation of the secretome from each cell line yielded clues about strategies used for breast cancer proliferation and metastasis. Some of the proteins we identified may be useful in the development of a serum-based test for breast cancer detection, diagnosis, prognosis, and monitoring.

Loss of TFF1 promotes Helicobacter pylori-induced β-catenin activation and gastric tumorigenesis

Using in vitro and in vivo models, we investigated the role of TFF1 in suppressing H. pylori-mediated activation of oncogenic β-catenin in gastric tumorigenesis. A reconstitution of TFF1 expression in gastric cancer cells decreased H. pylori-induced β-catenin nuclear translocation, as compared to control (p < 0.001). These cells exhibited significantly lower β-catenin transcriptional activity, measured by pTopFlash reporter, and induction of its target genes (CCND1 and c-MYC), as compared to control. Because of the role of AKT in regulating β-catenin, we performed Western blot analysis and demonstrated that TFF1 reconstitution abrogates H. pylori-induced p-AKT (Ser473), p-β-catenin (Ser552), c-MYC, and CCND1 protein levels. For in vivo validation, we utilized the Tff1-KO gastric neoplasm mouse model. Following infection with PMSS1 H. pylori strain, we detected an increase in the nuclear staining for β-catenin and Ki-67 with a significant induction in the levels of Ccnd1 and c-Myc in the stomach of the Tff1-KO, as compared to Tff1-WT mice (p < 0.05). Only 10% of uninfected Tff1-KO mice, as opposed to one-third of H. pylori-infected Tff1-KO mice, developed invasive adenocarcinoma (p = 0.03). These findings suggest that loss of TFF1 could be a critical step in promoting the H. pylori-mediated oncogenic activation of β-catenin and gastric tumorigenesis.

Increased immunoexpression of trefoil factors in salivary gland tumors

OBJECTIVE

Very little is known about the role of trefoil factors (TFFs) in salivary gland tumors, and TFF immunoexpression has never been investigated in such tumors. The aim of this study was to evaluate TFF immunoexpression in benign and malignant salivary gland tumors.

MATERIALS AND METHODS

Benign (n = 25) and malignant (n = 25) salivary gland tumor specimens were included in this study, using mucocele (n = 25) specimens as a control group. Immunohistochemical staining was performed to evaluate the expression of TFFs (TFF1, TFF2, and TFF3) by semiquantitative means.

RESULTS

Expression of TFF1, TFF2, and TFF3 was significantly increased in benign (p = 0.001, p = 0.005, p < 0.001, respectively) and malignant (p < 0.001, p < 0.001, p < 0.001, respectively) groups as compared with the control group. Patterns of co-expression between TFF1/TFF2, TFF2/TFF3, and TFF1/TFF3 were different among the three groups.

CONCLUSIONS

The present study provided new information showing that all TFFs were significantly increased in benign and malignant salivary gland tumors, and overexpression of TFFs could be associated with neoplastic transformation in salivary gland tissues.

CLINICAL RELEVANCE

Overexpression of TFFs may be useful as biomarkers in terms of differential diagnosis between salivary gland tumors and other oral neoplasms for which clinical manifestations are indistinguishable.

Trefoil factor family peptides – friends or foes?

Trefoil factor family (TFF) peptides are a group of molecules bearing a characteristic three-loop trefoil domain. They are mainly secreted in mucous epithelia together with mucins but are also synthesized in the nervous system. For many years, TFF peptides were only known for their wound healing and protective function, e.g. in epithelial protection and restitution. However, experimental evidence has emerged supporting a pivotal role of TFF peptides in oncogenic transformation, tumorigenesis and metastasis. Deregulated expression of TFF peptides at the gene and protein level is obviously implicated in numerous cancers, and opposing functions as oncogenes and tumor suppressors have been described. With regard to the regulation of TFF expression, epigenetic mechanisms as well as the involvement of various miRNAs are new, promising aspects in the field of cancer research. This review will summarize current knowledge about the expression and regulation of TFF peptides and the involvement of TFF peptides in tumor biology and cancerogenesis.

Exploring DNA methylation changes in promoter, intragenic, and intergenic regions as early and late events in breast cancer formation

BACKGROUND

Breast cancer formation is associated with frequent changes in DNA methylation but the extent of very early alterations in DNA methylation and the biological significance of cancer-associated epigenetic changes need further elucidation.

METHODS

Pyrosequencing was done on bisulfite-treated DNA from formalin-fixed, paraffin-embedded sections containing invasive tumor and paired samples of histologically normal tissue adjacent to the cancers as well as control reduction mammoplasty samples from unaffected women. The DNA regions studied were promoters (BRCA1, CD44, ESR1, GSTM2, GSTP1, MAGEA1, MSI1, NFE2L3, RASSF1A, RUNX3, SIX3 and TFF1), far-upstream regions (EN1, PAX3, PITX2, and SGK1), introns (APC, EGFR, LHX2, RFX1 and SOX9) and the LINE-1 and satellite 2 DNA repeats. These choices were based upon previous literature or publicly available DNA methylome profiles. The percent methylation was averaged across neighboring CpG sites.

RESULTS

Most of the assayed gene regions displayed hypermethylation in cancer vs. adjacent tissue but the TFF1 and MAGEA1 regions were significantly hypomethylated (p ≤0.001). Importantly, six of the 16 regions examined in a large collection of patients (105 - 129) and in 15-18 reduction mammoplasty samples were already aberrantly methylated in adjacent, histologically normal tissue vs. non-cancerous mammoplasty samples (p ≤0.01). In addition, examination of transcriptome and DNA methylation databases indicated that methylation at three non-promoter regions (far-upstream EN1 and PITX2 and intronic LHX2) was associated with higher gene expression, unlike the inverse associations between cancer DNA hypermethylation and cancer-altered gene expression usually reported. These three non-promoter regions also exhibited normal tissue-specific hypermethylation positively associated with differentiation-related gene expression (in muscle progenitor cells vs. many other types of normal cells). The importance of considering the exact DNA region analyzed and the gene structure was further illustrated by bioinformatic analysis of an alternative promoter/intron gene region for APC.

CONCLUSIONS

We confirmed the frequent DNA methylation changes in invasive breast cancer at a variety of genome locations and found evidence for an extensive field effect in breast cancer. In addition, we illustrate the power of combining publicly available whole-genome databases with a candidate gene approach to study cancer epigenetics.

Evaluating the utility of trefoil factor 1 as a mammary-specific immunostain compared and in conjunction with GATA-3 and mammaglobin in the distinction between carcinoma of breast and lung

OBJECTIVES

The distinction between metastatic breast carcinomas (BCs) and primary lung carcinomas (PLCs) can be difficult. This study tested the utility of trefoil factor 1 (TFF1) for this purpose and compared it with mammaglobin and GATA protein binding 3 (GATA-3).

METHODS

Tissue microarrays containing 365 BCs and 338 PLCs were stained with TFF1, mammaglobin, and GATA-3, and an H-score was calculated. Sensitivity, specificity, and accuracy were calculated, and logistical regression analysis was performed.

RESULTS

Accuracy of correctly classifying the tumor type was 81.9%, 71.3%, and 64.0% for GATA-3, mammaglobin, and TFF1, respectively. Odds ratios for selecting BCs were 25.69, 93.15, and 4.17, respectively, with P values less than .001. With a single exception, the best immunopanel included GATA-3 and mammaglobin in all comparisons.

CONCLUSIONS

TFF1 demonstrated breast specificity but was inferior to mammaglobin and GATA-3. Therefore, its routine clinical use may not be justified. TFF1 showed little benefit when added to an immunopanel.

Trefoil factors: Gastrointestinal-specific proteins associated with gastric cancer

Trefoil factor family (TFF), composed of TFF1, TFF2, and TFF3, is a cluster of secreted peptides characterized by trefoil domain (s) and C-terminal dimerization domain. TFF1, a gastric tumor suppressor, is a single trefoil peptide originally detected in breast cancer cell lines but expressed mainly in the stomach; TFF2, a candidate of gastric cancer suppressor with two trefoil domains, is abundant in the stomach and duodenal Brunner's glands; and TFF3 is another single trefoil peptide expressed throughout the intestine which can promote the development of gastric carcinoma. According to multiple studies, TFFs play a regulatory function in the mammals' digestive system, namely in mucosal protection and epithelial cell reconstruction, tumor suppression or promotion, signal transduction and the regulation of proliferation and apoptosis. Action mechanisms of TFFs remain unresolved, but the recent demonstration of a GKN (gastrokine) 2-TFF1 heterodimer implicates structural and functional interplay with gastrokines. This review aims to encapsulate the structural and biological characteristics of TFF.

Activation of β-catenin signalling by TFF1 loss promotes cell proliferation and gastric tumorigenesis

OBJECTIVE

In this study, we investigated the role of Trefoil factor 1 (TFF1) in regulating cell proliferation and tumour development through β-catenin signalling using in vivo and in vitro models of gastric tumorigenesis.

DESIGN

Tff1-knockout (Tff1-KO) mice, immunohistochemistry, luciferase reporter, qRT-PCR, immunoblot, and phosphatase assays were used to examine the role of TFF1 on β-catenin signalling pathway.

RESULTS

Nuclear localisation of β-catenin with transcriptional upregulation of its target genes, c-Myc and Ccnd1, was detected in hyperplastic tissue at an early age of 4-6 weeks and maintained during all stages of gastric tumorigenesis in the Tff1-KO mice. The reconstitution of TFF1 or TFF1 conditioned media significantly inhibited the β-catenin/T-cell factor (TCF) transcription activity in MKN28 gastric cancer cells. In agreement with these results, we detected a reduction in the levels of nuclear β-catenin with downregulation of c-MYC and CCND1 mRNA. Analysis of signalling molecules upstream of β-catenin revealed a decrease in phosphorylated glycogen synthase kinase 3β (p-GSK3β) (Ser9) and p-AKT (Ser473) protein levels following the reconstitution of TFF1 expression; this was consistent with the increase of p-β-catenin (Ser33/37/Thr41) and decrease of p-β-catenin (Ser552). This TFF1-induced reduction in phosphorylation of GSK3β, and AKT was dependent on protein phosphatase 2A (PP2A) activity. The treatment with okadaic acid or knockdown of PP2A abrogated these effects. Consistent with the mouse data, we observed loss of TFF1 and an increase in nuclear localisation of β-catenin in stages of human gastric tumorigenesis.

CONCLUSIONS

Our data indicate that loss of TFF1 promotes β-catenin activation and gastric tumorigenesis through regulation of PP2A, a major regulator of AKT-GSK3β signalling.

TFF1 activates p53 through down-regulation of miR-504 in gastric cancer

The expression of TFF1 is frequently down-regulated in human gastric cancer whereas its knockout leads to the development of gastric adenomas and carcinomas in mouse models. The molecular mechanisms underlying the TFF1 tumor suppressor functions remain unclear. In this study, we demonstrate, using colony formation assay and Annexin V staining, that reconstitution of TFF1 expression in gastric cancer cell models suppresses cell growth and promotes cell death. Furthermore, using a tumor xenograft mouse model of gastric cancer, we demonstrated that reconstitution of TFF1 suppresses tumor growth in vivo. The results from PG13-luciferase reporter assay and Western blot analysis indicated that TFF1 promotes the expression and transcription activity of the p53 protein. Further analysis using cycloheximide-based protein assay and quantitative real-time PCR data suggested that TFF1 does not interfere with p53 mRNA levels or protein stability. Alternatively, we found that the reconstitution of TFF1 down-regulates miR-504, a negative regulator of p53. Western blot analysis data demonstrated that miR-504 abrogates TFF1-induced p53 protein expression and activity. In conclusion, the in vitro and in vivo data demonstrate, for the first time, a novel mechanism by which the tumor suppressor functions of TFF1 involve activation of p53 through down-regulation of miR-504.

Functional expression of recombinant human trefoil factor 1 by Escherichia coli and Brevibacillus choshinensis

Background

Trefoil factor 1 (TFF1) mediates mucosal repair and belongs to a highly conserved trefoil factor family proteins which are secreted by epithelial cells in the stomach or colon mucous membrane. TFF1 forms a homodimer via a disulphide linkage that affects wound healing activity. Previous recombinant expressions of TFF1 were too low yield for industrial application. This study aims to improve the expression level of bioactive recombinant TFF1 (rTFF1) and facilitate application potency.

Methods

The rTFF1 gene rtff1 was synthesized, expressed by Escherichia coli and secreted by Brevibacillus choshinensis. The rTFF1s were purified. The polymeric patterns and wound healing capacities of purified rTFF1s were checked.

Results

In Escherichia coli, 21.08 mg/L rTFF1 was stably expressed as monomer, dimer and oligomer in soluble fraction. In Brevebacillus choshinensis, the rTFF1 was secreted extracellularly at high level (35.73 mg/L) and formed monomer, dimer and oligomer forms. Both proteins from different sources were purified by Ni-NTA chromatography and exhibited the wound healing activities. The rTFF1 produced by B. choshinensis had better wound healing capability than the rTFF1 produced by E. coli. After pH 2.4 buffer treatments, the purified rTFF1 formed more oligomeric forms as well as better wound healing capability. Glycosylation assay and LC-MS/MS spectrometry experiments showed that the rTFF1 produced by B. choshinensis was unexpectedly glycosylated at N-terminal Ser residue. The glycosylation may contribute to the better wound healing capacity.

Conclusions

This study provides a potent tool of rTFF1 production to be applied in gastric damage protection and wound healing. The protein sources from B. choshinensis were more efficient than rTFF1 produced by E. coli.

Electronic supplementary material

The online version of this article (doi:10.1186/s12896-015-0149-5) contains supplementary material, which is available to authorized users.

The value of trefoil factor 3 expression in predicting the long‑term outcome and early recurrence of colorectal cancer

The trefoil factor (TFF) family comprises three thermo-stable and protease-resistant proteins (TFF1, TFF2 and TFF3) and plays an essential role in gastrointestinal mucosa protection and regeneration, and TFFs have recently been found to be involved in the development and progression of various types of cancer. However, the clinical significance of TFFs in colorectal cancer (CRC) patients remains unclear. The present study determined the relationship between TFF expression and clinicopathological findings, as well as long-term outcome in CRC patients. The mRNA expression levels of TFFs were examined in the excised CRC specimens obtained from 154 consecutive CRC patients who underwent surgical resection between 2005 and 2007 at our institution. TFF3 expression was significantly associated with the presence of distant metastasis (p=0.017), although neither TFF1 nor TFF2 expression was associated with the clinicopathological features. Survival rate of the patients with positive TFF3 was significantly worse compared to those with negative TFF3 (p=0.011). A multivariate analysis revealed that the expression of TFF3, lymph node metastasis, and vascular invasion were independent prognostic factors for disease-specific survival. Furthermore, among 134 patients with no clinical findings of metastasis at surgery, the patients with positive TFF3 experienced recurrence within one year more frequently than those with negative TFF3 (p=0.039). In conclusion, TFF3 is not only a useful biomarker for a long-term surgical result in CRC patient, but also may be a risk factor of early recurrence.

Trefoil Factor 1 is involved in gastric cell copper homeostasis

Trefoil Factor 1 belongs to a group of small secreted proteins (the Trefoil Factor Family proteins), that are localized within the mucous granules and are expressed and secreted by epithelial cells that line mucous membranes. Trefoil factors are mainly expressed in the gastrointestinal tract, where they normally contribute to maintain the integrity of the mucosa. We recently demonstrated a selective binding ability of Trefoil Factor 1 for copper ions, through its carboxy-terminal tail, and we also observed that copper levels influence the equilibrium between the monomeric and homodimeric forms of Trefoil Factor 1, thus modulating its biological activity. Here we report that transcriptional regulation of Trefoil Factor 1 is also affected by copper levels, through the modulated binding of the copper-sensing transcription factor Sp1 onto the responsive elements present in the regulatory region of the gene. In addition we demonstrate that copper overload causes an accumulation of the trefoil protein in the Trans-Golgi Network and that Trefoil Factor 1 levels can influence copper excretion and copper related toxicity. These findings suggest that the protein might play a role in the overall complex mechanisms of copper homeostasis in the gastrointestinal tissues.

Functional variants at the 21q22.3 locus involved in breast cancer progression identified by screening of genome-wide estrogen response elements

Introduction

Estrogen forms a complex with the estrogen receptor (ER) that binds to estrogen response elements (EREs) in the regulatory region of estrogen-responsive genes and regulates their transcription. Sequence variants in the regulatory regions have the potential to affect the transcription factor–regulatory sequence interaction, resulting in altered expression of target genes. This study explored the association between single-nucleotide polymorphisms (SNPs) within the ERE-associated sequences and breast cancer progression.

Methods

The ERE-associated sequences throughout the whole genome that have been demonstrated to bind ERα in vivo were blasted against online information from SNP data sets and 54 SNPs located adjacent to estrogen-responsive genes were selected for genotyping in two independent cohorts of breast cancer patients: 779 patients in the initial screening stage and another 888 in the validation stage. Deaths due to breast cancer or recurrence of breast cancer were defined as the respective events of interest, and the hazard ratios of individual SNPs were estimated based on the Cox proportional hazards model. Furthermore, functional assays were performed, and information from publicly available genomic data and bioinformatics platforms were used to provide additional evidence for the associations identified in the association analyses.

Results

The SNPs at 21q22.3 ERE were significantly associated with overall survival and disease-free survival of patients. Furthermore, these 21q22.3 SNPs (rs2839494 and rs1078272) could affect the binding of this ERE-associated sequence to ERα or Rad21 (an ERα coactivator), respectively, which resulted in a difference in ERα-activated expression of the reporter gene.

Conclusion

These findings support the idea that functional variants in the ERα-regulating sequence at 21q22.3 are important in determining breast cancer progression.

Electronic supplementary material

The online version of this article (doi:10.1186/s13058-014-0455-1) contains supplementary material, which is available to authorized users.

HITS-CLIP reveals key regulators of nuclear receptor signaling in breast cancer

miRNAs regulate the expression of genes in both normal physiology and disease. While miRNAs have been demonstrated to play a pivotal role in aspects of cancer biology, these reports have generally focused on the regulation of single genes. Such single-gene approaches have significant limitations, relying on miRNA expression levels and heuristic predictions of mRNA-binding sites. This results in only circumstantial evidence of miRNA-target interaction and typically leads to large numbers of false positive predictions. Here, we used a genome-wide approach (high-throughput sequencing of RNA isolated by crosslinking immunoprecipitation, HITS-CLIP) to define direct miRNA-mRNA interactions in three breast cancer subtypes (estrogen receptor positive, Her2 amplified, and triple negative). Focusing on steroid receptor signaling, we identified two novel regulators of the ER pathway (miR-9-5p and miR-193a/b-3p), which together target multiple genes involved in ER signaling. Moreover, this approach enabled the definition of miR-9-5p as a global regulator of steroid receptor signaling in breast cancer. We show that miRNA targets and networks defined by HITS-CLIP under physiologic conditions are predictive of patient outcomes and provide global insight into miRNA regulation in breast cancer.

Multiple endocrine neoplasia type 1 associated with breast cancer: A case report and review of the literature

Multiple endocrine neoplasia type 1 (MEN1) is a cancer predisposition syndrome that includes a combination of endocrine and non-endocrine tumors. The present study reports a rare case of MEN1 associated with breast cancer with the MEN1 gene mutation. A 45-year-old female was diagnosed with breast cancer subsequent to presenting with a right breast mass. Pre-operative radiological studies indicated right breast cancer with a suspicious metastatic nodule of the lung. Further studies demonstrated bilateral thyroid nodules, a neuroendocrine tumor of the pancreas, paraganglioma, a left adrenal adenoma, gallstones, uterine subserosal myoma and pituitary macroadenoma. Laboratory examinations revealed hypercalcemia, hypophosphatemia and an increased intact parathyroid hormone level. The workup for the suspected MEN syndrome revealed an increased basal plasma level of insulin-like growth factor-1, prolactin and calcitonin, and an increased 24-h urinary free cortisol level. The patient underwent surgical removal of the breast cancer and the tumors of the pancreas, adrenal gland, thyroid and parathyroid glands, uterus, anterior mediastinum and lung. The pathological diagnosis of the resected breast was of invasive ductal carcinoma. Otherwise the pathological diagnosis was of calcitonin-producing pancreatic endocrine carcinoma, adrenal cortical adenoma, bilateral papillary thyroid carcinomas, parathyroid adenomas, uterine leiomyoma with adenomyosis, a thymic carcinoid tumor and lung hamatoma. Gene analysis was performed to determine the association between gene mutations and the development of tumors in this patient, and a germ-line MEN1 gene mutation was consequently detected. It could be assumed that MEN1 syndrome may have possibly predisposed the present patient to breast cancer. However, additional observations and further studies are required to demonstrate this association.

Trefoil factor 1 in early breast carcinoma: a potential indicator of clinical outcome during the first 3 years of follow-up

BACKGROUND

A role of an estrogen-regulated, autocrine motogenic factor was assumed to be a major biological role of trefoil factor 1 (TFF1) in breast cancer. TFF1 is regarded as a predictive factor for positive response to endocrine therapy in breast cancer patients. The aim of our study was to examine TFF1 level distribution in breast carcinomas in order to distinguish estrogen-independent from estrogen-dependent TFF1 expression and to evaluate clinical usefulness of TFF1 status in early breast cancer during the first 3 years of follow-up.

METHODS

The study included 226 patients with primary operable invasive early breast carcinomas for whom an equal, a 3-year follow-up was conducted. TFF1 levels as well as estrogen receptor (ER) and progesterone receptor (PR) levels were measured in cytosolic extracts of tumor samples by immunoradiometric assay or by use of classical biochemical method, respectively. Non-parametric statistical tests were applied for data analyses.

RESULTS

Statistical analysis revealed that TFF1 levels were significantly higher in premenopausal patients (p=0.02), or in tumors with: lower histological grade (p<0.001), positive ER or PR status (p<0.001, in both cases). On the basis of TFF1 level distribution between ER-negative and ER-positive postmenopausal patients with tumors of different histological grade, 14 ng/mg was set as the cut-off value to distinguish estrogen-independent from estrogen-dependent TFF1 expression in breast cancer. Depending on menopausal and PR status, positive TFF1 status identified patients at opposite risk for relapse among ER-positive patients with grade II tumors. Among ER- and PR-positive premenopausal patients with grade II tumors, TFF1 status alone identified patients at opposite risk for relapse.

CONCLUSIONS

Determination of TFF1 status might identify patients at different risk for relapse and help in making decision on administering adjuvant therapy for early breast cancer patients during the first 3 years of follow-up.

Trefoil factor family 3 (TFF3) expression and its interaction with estrogen receptor (ER) in endometrial adenocarcinoma

OBJECTIVES

TFF3 has been found to be up-regulated at the gene and protein levels in endometrioid adenocarcinoma (EAC) when compared to uterine serous carcinoma (USC) and normal endometrium. In addition, TFF3 has been proven to be an estrogen-responsive gene and its expression level positively correlated to estrogen-receptor (ER) status in breast cancer cell culture. The aims of this study are to determine the expression and the prognostic value of TFF3 in a large series of human endometrial cancer and its relation with ER.

METHODS

We evaluated 328 endometrial carcinomas using TFF3 and ER antibody on paraffin-embedded tissue. 74% were type I (EAC), and 26% were type II (USC, CCC and carcinosarcoma).

RESULTS

In type I carcinomas, TFF3(+) expression was associated with no lympho-vascular invasion (p=0.0131), disease status (p=0.0132), recurrence-free survival (p=0.0424) and overall survival (p=0.0018). There was a positive association between TFF3 and ER (p<.0001). The combination of TFF3(+)/ER(+) was associated with low FIGO grade (p=.0122), early FIGO stage (p=.0062), absence of recurrence (p=.0037), absence of LVI (p=.0011), no lymph node involvement (p=.0116) and disease status (p=.0107). TFF3 appeared to be an independent prognostic marker in predicting recurrences (p=.046). In type II carcinomas, TFF3 failed to have a prognostic value.

CONCLUSION

1-TFF3 seems to be a novel pathway in the pathogenesis of type I endometrial carcinomas. 2-The strong association of TFF3 and ER in the estrogen-dependent endometrioid carcinoma could explain the reason for its frequent expression by this tumor type. 3-TFF3(+) seems to forecast a good prognosis in type I endometrial carcinomas. Based on our data, TFF3 expression in endometrial cancer deserves further investigation.

Loss of trefoil factor 1 is regulated by DNA methylation and is an independent predictive factor for poor survival in advanced gastric cancer

Trefoil factor 1 (TFF1) is considered to be a tumor suppressor gene in gastric cancer. However, the role of TFF1 expression and its regulation in gastric cancer patients remain unclear. The aims of this study were to clarify the clinical significance of TFF1 and to determine its regulatory mechanisms. We assessed the immunohistochemical expression of TFF1 in 182 gastric cancer patients and examined whether or not TFF1 is associated with the clinicopathological factors and patient survival. In vitro study using TFF1 knockdown gastric cancer cells evaluated the role of TFF1 in cancer invasion. Bisulfite sequencing was performed to assess DNA methylation of TFF1 in cells and resected tissues. Patients with low expression of TFF1 showed a significantly deeper invasion of the tumor than those with high expression (p=0.037). Low expression of TFF1 was also associated with a poor survival (p=0.029) in 108 patients who were treated by surgery alone. Both TFF1 expression and lymph node metastasis are independent predictive factors for disease-specific survival in a multivariate analysis. In an in vitro study, invasive power of the cells was significantly increased in the TFF1‑deficient cells compared with the control cells. Bisulfate sequencing showed that TFF1 expression is strongly dependent on DNA methylation in both gastric cancer cells and tissues. Interestingly, methylation status of two specific CpG sites, which are located close to a TATA box and hypoxia response element (HRE), determined the TFF1 expression in the resected tissues. TFF1 expression is silenced by DNA methylation and is associated with tumor invasion and a poor survival in gastric cancer patients. The expression and̸or methylation status of TFF1 may, therefore, serve as a useful biomarker for predicting survival in patients with advanced gastric cancer.

Exploiting MEK inhibitor-mediated activation of ERα for therapeutic intervention in ER-positive ovarian carcinoma

While the clinical benefit of MEK inhibitor (MEKi)-based therapy is well established in Raf mutant malignancies, its utility as a suppressor of hyperactive MAPK signaling in the absence of mutated Raf or Ras, is an area of ongoing research. MAPK activation is associated with loss of ERα expression and hormonal resistance in numerous malignancies. Herein, we demonstrate that MEKi induces a feedback response that results in ERα overexpression, phosphorylation and transcriptional activation of ER-regulated genes. Mechanistically, MEKi-mediated ERα overexpression is largely independent of erbB2 and AKT feedback activation, but is ERK-dependent. We subsequently exploit this phenomenon therapeutically by combining the ER-antagonist, fulvestrant with MEKi. This results in synergistic suppression of tumor growth, in vitro and potentiation of single agent activity in vivo in nude mice bearing xenografts. Thus, we demonstrate that exploiting adaptive feedback after MEKi can be used to sensitize ERα-positive tumors to hormonal therapy, and propose that this strategy may have broader clinical utility in ERα-positive ovarian carcinoma.

Gastrokines: stomach-specific proteins with putative homeostatic and tumor suppressor roles

During the past decade, a new family of stomach-specific proteins has been recognized. Known as "gastrokines" (GKNs), these secreted proteins are products of gastric mucus-producing cell lineages. GKNs are highly conserved in physical structure, and emerging data point to convergent functions in the modulation of gastric mucosal homeostasis and inflammation. While GKNs are highly prevalent in the normal stomach, frequent loss of GKN expression in gastric cancers, coupled with established antiproliferative activity, suggests putative tumor suppressor roles. Conversely, ectopic expression of GKNs in reparative lesions of Crohn's disease alludes to additional activity in epithelial wound healing and/or repair. Modes of action remain unsolved, but the recent demonstration of a GKN2-trefoil factor 1 heterodimer implicates functional interplay with trefoil factors. This review aims to provide a historical account of GKN biology and encapsulate the rapidly accumulating evidence supporting roles in gastric epithelial homeostasis and tumor suppression.

Brefeldin A is an estrogenic, Erk1/2-activating component in the extract of Agaricus blazei mycelia

We purified an Erk1/2-activating component in Agaricus blazei and identified it as brefeldin A (BFA). The extract of A. blazei mycelia (ABE) previously showed an estrogenic gene-expression profile and positive effects in patients with cardiovascular symptoms. Here, we demonstrate that BFA has estrogenic activity in reporter gene assays and stimulates an estrogen-receptor pathway revealed by activation of Erk1/2, although BFA had no growth-stimulating activity in breast cancer MCF-7 cells. The presence of estrogenic activity without any explicit growth-stimulating effect is unique to BFA, and such components are termed here "silent estrogens". To test this hypothesis, we examined the target-gene transcription and signaling pathways induced by BFA. Furthermore, BFA was found in the mycelium but not fruiting body of A. blazei, suggesting the potential use of ABE for therapeutics and its supplementary use in traditional medicines and functional foods.

Trefoil factor 1 suppression of E-CADHERIN enhances prostate carcinoma cell invasiveness and metastasis

Metastasis is the primary mediator of prostate cancer (PCA) lethality and poses a significant clinical obstacle. The identification of factors involved in the metastasis of PCA is imperative. We demonstrate herein that trefoil factor 1 (TFF1) promotes PCA cell migration and invasion in vitro and metastasis in vivo. The capacity of TFF1 to enhance cell migration/invasion is mediated by transcriptional repression of E-CADHERIN. Consideration of targeted inhibition of TFF1 to prevent metastasis of prostate carcinoma is warranted.

Analysis of gene expression data from non-small cell lung carcinoma cell lines reveals distinct sub-classes from those identified at the phenotype level

Microarray data from cell lines of Non-Small Cell Lung Carcinoma (NSCLC) can be used to look for differences in gene expression between the cell lines derived from different tumour samples, and to investigate if these differences can be used to cluster the cell lines into distinct groups. Dividing the cell lines into classes can help to improve diagnosis and the development of screens for new drug candidates. The micro-array data is first subjected to quality control analysis and then subsequently normalised using three alternate methods to reduce the chances of differences being artefacts resulting from the normalisation process. The final clustering into sub-classes was carried out in a conservative manner such that sub-classes were consistent across all three normalisation methods. If there is structure in the cell line population it was expected that this would agree with histological classifications, but this was not found to be the case. To check the biological consistency of the sub-classes the set of most strongly differentially expressed genes was be identified for each pair of clusters to check if the genes that most strongly define sub-classes have biological functions consistent with NSCLC.

SUMOylation of ZFP282 potentiates its positive effect on estrogen signaling in breast tumorigenesis

Estrogen receptor α (ERα) has critical roles in the development and progression of breast cancer, and the coiled-coil co-activator (CoCoA) is an important ERα co-activator for estrogen-induced gene expression. The small ubiquitin-like modifier (SUMO) pathway is hyperactivated in breast cancer, but the mechanism by which SUMOylation regulates ERα-mediated transcription remains poorly understood. Here, we identified ZFP282 as a CoCoA-binding protein. ZFP282 associates directly with ERα and cooperates synergistically with CoCoA to enhance ERα function. ZFP282 is required for estrogen-induced expression of ERα target genes and estrogen-dependent breast cancer cell growth and tumorigenesis. In addition, we found that ZFP282 is SUMOylated and that SUMOylation positively regulates the co-activator activity of ZFP282 by increasing its binding affinity to ERα and CoCoA, and consequently increasing recruitment of ZFP282-CoCoA complex to the promoter of ERα target genes. These findings reveal essential roles for ZFP282 and its SUMOylation in estrogen signaling and breast tumorigenesis.

High trefoil factor 1 (TFF1) expression in human retinoblastoma cells correlates with low growth kinetics, increased cyclin-dependent kinase (CDK) inhibitor levels and a selective down-regulation of CDK6

Trefoil factor family (TFFs) peptides facilitate epithelial restitution, but also effect cell proliferation and apoptosis of normal and various cancer cell lines. In a recent study by our group, TFF2 expression was demonstrated in the murine retina, where it exhibits pro-proliferative and pro-apoptotic effects. In the present study, we investigated the expression and function of TFF peptides in eight human retinoblastoma cell lines. TFF1 was the only TFF peptide expressed at detectable levels in immunoblots of retinoblastoma cells. TFF1 expression levels were highly variable in different retinoblastoma cell lines and negatively correlated with cell growth curves. Recombinant human TFF1 had a negative effect on cell viability and caused a reduction in cell proliferation. Retinoblastoma cell lines with high TFF1 expression levels exhibited a selective down-regulation of cyclin-dependent kinase (CDK) 6, whereas CDK4 and CDK2 seem to be unaffected by TFF1 expression. In immunocytochemical studies, we observed a nuclear co-localization of TFF1 and CDK2 in Cajal bodies (CBs). In high TFF1 expressing human retinoblastoma cell lines CBs were smaller and higher in number compared to retinoblastoma lines with low TFF1 expression, indicating differences in cell cycle status between the different retinoblastoma cell lines. Our data further support the notion for a potential tumor suppressor function of TFF1. The nuclear localization of TFF1 in CBs--considered to play a role in cell cycle progression, potentially acting as a platform for CDK-cyclin function-offers a new impetus in the ongoing search for potential TFF1 interacting proteins.

Histone H3 phosphorylation, immediate-early gene expression, and the nucleosomal response: a historical perspective1This article is part of Special Issue entitled Asilomar Chromatin and has undergone the Journal’s usual peer review process

Histone H3 is modified at serines 10 and 28 in interphase cells following activation of the RAS-MAPK or p38-MAPK pathways by growth factors or stress. These modifications are involved in the regulation of immediate-early genes, including Jun and Fos, whose increased expression is a trademark of various cancers. This review outlines the series of discoveries that led to the characterization of these modifications, the kinase, MSK1/2, which is activated by both MAPK pathways and directs phosphorylation of H3, and the mechanistic function of these modifications in transcriptional activation. Research examining the effect of deregulated MSK1/2 in human disorders, namely cancer, is evaluated. Recently, a number of reports proposed novel, intervening pathways leading to enrichment of phosphorylated serine 10 and 28 and the activation of MSK1/2. These novel pathways predict an even more complicated signalling mechanism for cell growth, apoptosis, and the immune response, suggesting that MSK1/2 is intrinsically responsible for an even greater number of biological processes. This review proposes that MSK1/2 is an optimal target for cancer therapy, based on its fundamental role in transmitting external signals into varied responses involved in cancer development.

Increased trefoil factor 3 levels in the serum of patients with three major histological subtypes of lung cancer

Lung cancer is the most common cause of cancer-related deaths in the world. The trefoil factor (TFF) family is composed of three thermostable, and protease-resistant proteins, named TFF1, TFF2 and TFF3. TFF protein levels have been found to be related to the development of various types of cancer. However, it is still unclear whether TFF proteins are differentially expressed in the serum of different histological subtypes of lung cancer compared to healthy individuals. In this study, we investigated the levels of TFF proteins in serum and lung tissues of 130 lung cancer patients (58 squamous cell lung carcinoma cases, 43 adenocarcinoma cases and 29 SCLC cases) and 60 healthy individuals. It was found that TFF1 and TFF2 have similar or slightly higher levels in these three subtypes of lung cancer compared to healthy individuals, while TFF3 levels were significantly higher in the examined lung cancer cases compared to healthy individuals. Immunoblot analyses of TFF1, TFF2 and TFF3 indicated that lung cancer tissues and lung cancer cell lines have a higher expression of the TFF3 protein, but not of TFF1 or TFF2 proteins, compared to tissues from healthy individuals or from the normal cell line. Quantitative RT-PCR analysis indicated higher levels of TFF3, but not TFF1 and TFF2, transcripts in lung cancer tissues or cell lines. These results show increased TFF3 levels in serum and lung tissues, suggesting that TFF3 may serve as a promising, easily detected biomarker of lung cancer.

SUMOylation and SUMO-interacting motif (SIM) of metastasis tumor antigen 1 (MTA1) synergistically regulate its transcriptional repressor function

Metastasis tumor antigen 1 (MTA1), a component of the Mi-2·nucleosome remodeling and deacetylase complex, plays a crucial role in gene transcription, but the mechanism involved remains largely unknown. Here, we report that MTA1 is a substrate for small ubiquitin-related modifier 2/3 (SUMO2/3) in vivo. Protein inhibitor of activated STAT (PIAS) proteins enhance SUMOylation of MTA1 and may participate in paralog-selective SUMOylation, whereas sentrin/SUMO-specific protease 1 (SENP1) and 2 may act as deSUMOylation enzymes for MTA1. Moreover, MTA1 contains a functional SUMO-interacting motif (SIM) at its C terminus, and SIM is required for the efficient SUMOylation of MTA1. SUMO conjugation on Lys-509, which is located within the SUMO consensus site, together with SIM synergistically regulates the co-repressor activity of MTA1 on PS2 transcription, probably by recruiting HDAC2 onto the PS2 promoter. Interestingly, MTA1 may up-regulate the expression of SUMO2 via interaction with RNA polymerase II and SP1 at the SUMO2 promoter. These findings not only provide novel mechanistic insights into the regulation of the transcriptional repressor function of MTA1 by SUMOylation and SIM but also uncover a potential function of MTA1 in modulating the SUMOylation pathway.