The trefoil factor 1 (TFF1) protein involved in doxorubicin-induced apoptosis resistance is upregulated by estrogen in breast cancer cells

Secretory Trefoil Factor 1 (TFF1) promotes gemcitabine resistance through chemokine receptor CXCR4 in Pancreatic Ductal Adenocarcinoma

Gemcitabine is the first-line treatment option for patients with locally advanced or metastatic pancreatic ductal adenocarcinoma (PDAC). However, the frequent adoption of resistance to gemcitabine by cancer cells poses a significant challenge in treating this aggressive disease. In this study, we focused on analyzing the role of trefoil factor 1 (TFF1) in gemcitabine resistance in PDAC. Analysis of PDAC TCGA and cell line datasets indicated an enrichment of TFF1 in the gemcitabine-resistant classical subtype and suggested an inverse correlation between TFF1 expression and sensitivity to gemcitabine treatment. The genetic ablation of TFF1 in PDAC cells enhanced their sensitivity to gemcitabine treatment in both in vitro and in vivo tumor xenografts. The biochemical studies revealed that TFF1 contributes to gemcitabine resistance through enhanced stemness, increasing migration ability of cancer cells, and induction of anti-apoptotic genes. We further pursued studies to predict possible receptors exerting TFF1-mediated gemcitabine resistance. Protein-protein docking investigations with BioLuminate software revealed that TFF1 binds to the chemokine receptor CXCR4, which was supported by real-time binding analysis of TFF1 and CXCR4 using SPR studies. The exogenous addition of TFF1 increased the proliferation and migration of PDAC cells through the pAkt/pERK axis, which was abrogated by treatment with a CXCR4-specific antagonist AMD3100. Overall, the present study demonstrates the contribution of the TFF1-CXCR4 axis in imparting gemcitabine resistance properties to PDAC cells.

Unveiling Gene Regulatory Networks That Characterize Difference of Molecular Interplays Between Gastric Cancer Drug Sensitive and Resistance Cell Lines

Gastric cancer is a leading cause of cancer-related deaths globally and chemotherapy is widely accepted as the standard treatment for gastric cancer. However, drug resistance in cancer cells poses a significant obstacle to the success of chemotherapy, limiting its effectiveness in treating gastric cancer. Although many studies have been conducted to unravel the mechanisms of acquired drug resistance, the existing studies were based on abnormalities of a single gene, that is, differential gene expression (DGE) analysis. Single gene-based analysis alone is insufficient to comprehensively understand the mechanisms of drug resistance in cancer cells, because the underlying processes of the mechanism involve perturbations of the molecular interactions. To uncover the mechanism of acquired gastric cancer drug resistance, we perform for identification of differentially regulated gene networks between drug-sensitive and drug-resistant cell lines. We develop a computational strategy for identifying phenotype-specific gene networks by extending the existing method, CIdrgn, that quantifies the dissimilarity of gene networks based on comprehensive information of network structure, that is, regulatory effect between genes, structure of edge, and expression levels of genes. To enhance the efficiency of identifying differentially regulated gene networks and improve the biological relevance of our findings, we integrate additional information and incorporate knowledge of network biology, such as hubness of genes and weighted adjacency matrices. The outstanding capabilities of the developed strategy are validated through Monte Carlo simulations. By using our strategy, we uncover gene regulatory networks that specifically capture the molecular interplays distinguishing drug-sensitive and drug-resistant profiles in gastric cancer. The reliability and significance of the identified drug-sensitive and resistance-specific gene networks, as well as their related markers, are verified through literature. Our analysis for differentially regulated gene network identification has the capacity to characterize the drug-sensitive and resistance-specific molecular interplays related to mechanisms of acquired drug resistance that cannot be revealed by analysis based solely on abnormalities of a single gene, for example, DGE analysis. Through our analysis and comprehensive examination of relevant literature, we suggest that targeting the suppressors of the identified drug-resistant markers, such as the Melanoma Antigen (MAGE) family, Trefoil Factor (TFF) family, and Ras-Associated Binding 25 (RAB25), while enhancing the expression of inducers of the drug sensitivity markers [e.g., Serum Amyloid A (SAA) family], could potentially reduce drug resistance and enhance the effectiveness of chemotherapy for gastric cancer. We expect that the developed strategy will serve as a useful tool for uncovering cancer-related phenotype-specific gene regulatory networks that provide essential clues for uncovering not only drug resistance mechanisms but also complex biological systems of cancer.

E2F1 Affects the Therapeutic Response to Neoadjuvant Therapy in Breast Cancer

This study is aimed at screening genes for predicting the sensitivity response and favorable outcome of neoadjuvant therapy in breast cancer. We downloaded neoadjuvant therapy genetic data of breast cancer and separated it into the pathological complete response (pCR) group and the non-pCR group. Differential expression analysis was performed to select the differentially expressed genes (DEGs). After that, we investigated the enriched biological processes and pathways of DEGs. Then, core up/down protein-protein interaction (PPI) network was, respectively, constructed to identify the hub genes. A transcription factor-target gene regulation network was built to screen core transcription factors (TFs). We found one upregulated DEG (KLHDC7B) and four downregulated DEGs (TFF1, LOC440335, SLC39A6, and MLPH) overlapped in three datasets. All DEGs were mainly enriched in pathways related to DNA biosynthesis, cell cycle, immune response, metabolism, and angiogenesis. The hub genes were KRT18, IL7R, HIST1H1A, and E2F1. The core TFs were HOXA9, SPDEF, FOXA1, E2F1, and PGR. RT-qPCR suggested that E2F1 was overexpressed in MCF-7, but HOXA9 was low-expressed. Western blot suggested that the MAPK signal pathway was inhibited in MCF-7/ADR. That is to say, some genes and core TFs can predict the sensitivity response of neoadjuvant therapy in breast cancer. And E2F1 may be involved in the process of drug resistance by regulating the MAPK signaling pathway. These might be useful as sensitive genes for the efficacy evaluation of neoadjuvant chemotherapy in breast cancer.

TFF1 gene single nucleotide polymorphism (rs3761376) and colorectal cancer risk

INTRODUCTION

Trefoil Factor 1 (TFF1) is a secretory peptide with gastrointestinal protective functions. Abnormal TFF1 expression is reported in some cancers and functional promoter polymorphism in TFF1 is believed to be associated with risk of gastric cancer. We evaluated rs3761376 in a sample of Iranian patients with colorectal cancer.

METHODS

Peripheral blood samples were taken from pathology confirmed cases of colorectal cancer and healthy volunteers. Genotyping was carried out using Restriction Fragment Length Polymorphism (RFLP) PCR. Any association with clinicopathologic data was assessed by SPSS version 19.

RESULTS

A total of 245 participants, including 122 patients with cancer and 123 non-cancer subjects were enrolled. Age, body mass index, and smoking habits were not significantly different between the two groups (P > 0.05). Distribution of TFF1 genotypes was not found to be associated with colorectal cancer. However, distant metastasis was more prevalent in carriers of the mutant allele.

CONCLUSION

TFF1 rs3761376 was not associated with colorectal cancer but it may be involved in metastasis. Therefore, further investigation is warranted to determine this relationship.

Genome-wide analysis of mRNA expression identified the involvement of trefoil factor 1 in the development of sessile serrated lesions

Precursor lesions that progress into colorectal cancer (CRC) could be largely classified into sessile serrated lesions (SSLs), traditional serrated adenoma (TSA), and tubular adenoma (TA). We aimed to determine whether high expression of trefoil factor 1 (TFF1) is closely associated with serrated lesions, particularly SSLs. The samples were divided into the first (12 SSLs, 5 TSAs, and 15 TAs) and second cohorts (15 SSLs, 9 TSAs, and 15 TAs). First, we investigated TFF1 expression in isolated gland samples using array-based and reverse-transcription PCR. Second, we performed immunohistochemical analysis of TFF1 expression in paraffin-embedded tissues obtained from SSL, TSA, TA, and hyperplastic polyp (HP) samples. In addition, we compared TFF1 mRNA levels between SSLs and HPs. TFF1 expression was significantly higher in SSLs than in TSA and TA in both cohorts. Additionally, immunohistochemical staining of TFF1 in the HP, SSL, TSA, and TA samples revealed significant differences in the immunohistochemical scores of TFF1 among the four types of lesions (higher expression in SSLs than in the other three lesions). Finally, there were significant differences in TFF1 mRNA expression levels between SSLs and HPs in paraffin-embedded tissues. However, there was considerable overlap in the immunohistochemical scores and expression levels of TFF1 transcripts between SSLs and HPs. The current findings may help elucidate the molecular mechanisms involved in serrated lesion development. In addition, we suggest that despite the limited practical application, upregulation of TFF1 transcripts may help differentiate SSLs from other lesions.

X-Box Binding Protein 1 (XBP1): A Potential Role in Chemotherapy Response, Clinical Pathologic Features, Non-Inflamed Tumour Microenvironment for Breast Cancer

X-box binding protein 1 (XBP1) is mainly expressed in breast cancer (BC) in human cancers. Its tumorigenesis and favourable prognosis are contradictory, and its essential role in chemotherapeutic response and immunosuppression is unknown in BC. The study firstly identified XBP1 who received neoadjuvant chemotherapy (NAC) from GSE25055 and GSE24460. Associations between XBP1 expression and clinicopathological characteristics was investigated using Oncomine, TCGA, UALCAN and bc-GenExMiner. The prognostic value of XBP1 was assessed using the Kaplan–Meier Plotter, bc-GenExMiner, GSE25055, and GSE25056. Furthermore, we systematically correlated XBP1 and immunological characteristics in the BC tumour microenvironment (TME) using TISIDB, TIMER, GSE25055, GSE25056 and TCGA dataset. Finally, an essential role of XBP1 in chemotherapy response was evaluated based on GSE25055, GSE25065, GSE24460, GSE5846, ROC Plotter and CELL databases. Furthermore, XBP1 mRNA expression levels were obviously highest in BC among human cancers and were significantly related to a good prognosis. In addition, XBP1 mRNA and protein levels were higher in the luminal subtype than in normal tissues and basal-like subtype, which might be attributed to membrane transport-related processes. Apart from BC, negative immunological correlations of XBP1 were not observed in other malignancies. XBP1 might shape the non-inflamed TME in BC. Finally, XBP1 expression was higher in chemo-resistive than chemo-sensitive cases, it had a predictive value and could independently predict chemotherapy response in BC patients receiving NAC. Our study suggests that the essential role of XBP1 in clinical pathologic features, non-inflamed TME, chemotherapy response in BC.

Aorta Regulatory T Cells with a Tissue-Specific Phenotype and Function Promote Tissue Repair through Tff1 in Abdominal Aortic Aneurysms

In addition to maintaining immune tolerance, Foxp3⁺ regulatory T cells (Tregs) perform specialized functions in tissue homeostasis and remodeling. However, whether Tregs in aortic aneurysms have a tissue-specific phenotype and function is unclear. Here, a special group of Tregs that potentially inhibit abdominal aortic aneurysm (AAA) progression are identified and functionally characterized. Aortic Tregs gradually increase during the process of AAA and are mainly recruited from peripheral circulation. Single-cell TCR sequencing and bulk RNA sequencing demonstrate their unique phenotype and highly expressed trefoil factor 1 (Tff1). Foxp3^cre/cre Tff1^flox/flox mice are used to clarify the role of Tff1 in AAA, suggesting that aortic Tregs secrete Tff1 to regulate smooth muscle cell (SMC) survival. In vitro experiments confirm that Tff1 inhibits SMC apoptosis through the extracellular signal-regulated kinase (ERK) 1/2 pathway. The findings reveal a tissue-specific phenotype and function of aortic Tregs and may provide a promising and novel approach for the prevention of AAA.

Long non-coding RNA FOXD3 antisense RNA 1 augments anti-estrogen resistance in breast cancer cells through the microRNA-363/ trefoil factor 1/ phosphatidylinositol 3-kinase/protein kinase B axis

Long non-coding RNA (lncRNA) FOXD3 antisense RNA 1 (FOXD3-AS1) has been reported to participate in multiple processes that contribute toward the development of cancer. The present study aimed to explore the effect of lncRNA FOXD3-AS1 on anti-estrogen resistance in breast cancer (BC) cells. FOXD3-AS1 was found to be highly expressed in BC cell lines. Moreover, FOXD3-AS1 was highly expressed in estrogen receptor-negative (ER^-) cells compared to the ER-positive (ER⁺) cells. FOXD3-AS1 overexpression in T47D and MCF-7 (ER⁺) cells enhanced the resistance of cells to tamoxifen (TMX), whereas FOX3-AS1 downregulation reduced the TMX resistance in MDA-MB-231 (ER^-) cells. Similar results were reproduced in vivo that FOXD3-AS1 inhibition reduced the growth of xenograft tumors formed by MDA-MB-231 cells following TMX treatment whereas FOXD3-AS1 overexpression in T47D cells facilitated tumor growth. The bioinformatic analysis and luciferase assays indicated that FOXD3-AS1 sponged microRNA-363 (miR-363) to restore expression of trefoil factor 1 (TFF1) mRNA. Overexpression of miR-363 reduced T47D cell proliferation induced by FOXD3-AS1, whereas overexpression of TFF1 restored growth of MDA-MB-231 cells reduced after FOXD3-AS1 silencing. The phosphorylation of phosphoinositide 3-kinase (PI3K)/protein kinase B (Akt) was increased by FOXD3-AS1 but attenuated by miR-363. Inhibition of PI3K/Akt blocked the role of FOXD3-AS1 and reduced the TMX resistance in T47D and MCF-7 cells. Taken together, the present study suggested that FOXD3-AS1 sponges miR-363 to upregulate TFF1 expression, leading to PI3K/Akt signaling activation and anti-estrogen resistance in BC cells.

A network approach reveals driver genes associated with survival of patients with triple-negative breast cancer

We aimed to identify triple-negative breast cancer (TNBC) drivers that regulate survival time as predictive signatures that improve TNBC prognostication. Breast cancer (BrCa) transcriptomic tumor biopsies were analyzed, identifying network communities enriched with TNBC-specific differentially expressed genes (DEGs) and correlated strongly to TNBC status. Two anticorrelated modules correlated strongly to TNBC subtype and survival. Querying module-specific hubs and DEGs revealed transcriptional changes associated with high survival. Transcripts were nominated as biomarkers and tested as combinatoric ratios using receiver operator characteristic (ROC) analysis to assess survival prediction. ROC test rounds integrated genes with established interactions to hubs and DEGs of key modules, improving prediction. Finally, we tested whether integration of literature-derived genes for implicated hallmark cancer processes could improve prediction of survival. Complementary coexpression, differential expression, genetic interaction, and survival stratification integrated by ROC optimization uncovered a panel of "linchpin survival genes" predictive of patient survival, representing gene interactions in hallmark cancer processes.

Odyssey of trefoil factors in cancer: Diagnostic and therapeutic implications

Trefoil factors 1, 2, and 3 (TFFs) are a family of small secretory molecules involved in the protection and repair of the gastrointestinal tract (GI). TFFs maintain and restore epithelial structural integrity via transducing key signaling pathways for epithelial cell migration, proliferation, and invasion. In recent years, TFFs have emerged as key players in the pathogenesis of multiple diseases, especially cancer. Initially recognized as tumor suppressors, emerging evidence demonstrates their key role in tumor progression and metastasis, extending their actions beyond protection. However, to date, a comprehensive understanding of TFFs' mechanism of action in tumor initiation, progression and metastasis remains obscure. The present review discusses the structural, functional and mechanistic implications of all three TFF family members in tumor progression and metastasis. Also, we have garnered information from studies on their structure and expression status in different organs, along with lessons from their specific knockout in mouse models. In addition, we highlight the emerging potential of using TFFs as a biomarker to stratify tumors for better therapeutic intervention.

Co-culture With Human Breast Adipocytes Differentially Regulates Protein Abundance in Breast Cancer Cells

BACKGROUND/AIM

Recent research highlights the role of cancer-associated adipocytes (CAA) in promoting breast cancer cell migration, invasion and resistance to therapy. This study aimed at identifying cellular proteins differentially regulated in breast cancer cells co-cultured with CAA.

MATERIALS AND METHODS

Adipocytes isolated from human breast adipose tissue were co-cultured with hormone receptor-positive (MCF-7) or -negative (MDA-MB-231) breast cancer cells using a transwell co-culture system. Proteomes of co-cultured and control breast cancer cells were compared quantitatively using iTRAQ labelling and tandem mass spectrometry, and the results were validated by western blotting.

RESULTS

A total of 1,126 and 1,218 proteins were identified in MCF-7 and MDA-MB-231 cells, respectively. Among these, 85 (MCF-7) and 63 (MDA-MB-231) had an average fold change >1.5 following co-culture. Pathway analysis revealed that CAA-induced enrichment of proteins involved in metabolism, the ubiquitin proteasome, and purine synthesis.

CONCLUSION

This study provides a proteomic platform for investigating the paracrine role of CAA in promoting breast cancer cell metastasis and resistance to therapy.

Trefoil factor 1 (TFF1) is a potential prognostic biomarker with functional significance in breast cancers

Breast cancer (BC) is the most common cancer in women and the second leading cause of their cancer death. Establishing an accurate BC prognosis is very difficult because of its heterogeneity. Elevated TFF1 levels in serum were associated with development of BC, TFF1 expression was upregulated in BC compared to the healthy breast tissue. The aim of this study was to investigate the function of TFF1 in BCs, and to assess whether serum TFF1 could be used in formulating a prognosis for BC patients. In silico analyses were carried out to determine the expression of TFF1 mRNA in different types of BC and the association between TFF1 expression and survival of BC patients. Expression of TFF1 protein was checked in 52 paraffin-embedded tissues of BCs by immunochemistry, and serum concentration of TFF1 in 70 BC patients and 32 healthy controls was measured by ELISA. Functional activities of TFF1 in BC cells were determined by CCK-8 assay, colony formation, BrdU-DNA synthesis, and assays for migration and invasion. Results showed that expression of TFF1 mRNA was correlated with expression of biomarkers of luminal cancers including ESR1, GATA3, FOXA1, MYB and XBP1. In addition, patients with ER⁺BC had higher expression of TFF1 than those with ER^- (p < 0.05). There was also lower expression of TFF1 in triple-negative breast cancer (TNBC) than in non-TNBC (p < 0.05), which corresponds with the level of serum TFF1 in TNBC patients, compared with non-TNBC patients (p < 0.001). Furthermore, expression of TFF1 was associated with tumor size (p = 0.002), nodal status (p < 0.001), histological grade (p < 0.001), ER status (p = 0.012), PR status (p < 0.001) and HER2 (p < 0.001), while serum TFF1 was only statistically different among BC with ER⁺, PR ⁺ and HER2⁺ (p = 0.04139, 0.0018, 0.0004). Elevated TFF1 expression correlated with increased overall survival of BC patients (p = 0.00068). Finally, TFF1 was found to inhibit the cell growth, colony formation, migration and invasion of BC cells in vitro. All these results suggest that expression of TFF1 was related to ER status of BC and that expression of TFF1 was lower in TNBC than in non-TNBC. TFF1 was found to inhibit proliferation, migration and invasion of BC cells in vitro. Expression of TFF1 was associated with clinical characters of patients with BC. Serum TFF1 could be used to predict prognosis of patients with BC, especially non-TNBC.

MicroRNA-16 sensitizes drug-resistant breast cancer cells to Adriamycin by targeting Wip1 and Bcl-2

Clinical evidence indicates that drug resistance is a major obstacle in the treatment of breast cancer (BC). Drug resistance results in the disease being uncontrollable, and leads to high mortality rates. The aim of the present study was to investigate the chemosensitizing effect of microRNA (miR)-16 on Adriamycin (ADM)-resistant BC cells and the associated mechanisms. BC tumors from 40 patients were collected and reverse transcription-quantitative PCR was used to examine the expression of miR-16. ADM-sensitive (MCF-7/S) and -resistant (MCF-7/A) BC cell lines were used to determine the expression of miR-16 prior to and following transfection with miR-16 mimics or inhibitor. The effects of increased and decreased miR-16 expression on the chemosensitivity of BC cells to ADM was analyzed using MTT, colony survival and flow cytometry assays. miR-16 was found to regulate wild-type p53-induced phosphatase 1 (Wip1) and Bcl-2 expression, as confirmed by western blotting, immunofluorescence staining and luciferase reporter assays. miR-16 expression in drug-resistant tumor tissues and cells was decreased, compared with that the drug-sensitive equivalents. Overexpression of miR-16 in MCF-7/A was associated with a sharp downregulation of Wip1 and Bcl-2 expression, leading to increased ADM-induced cell apoptosis and sensitization of MCF-7/A cells to ADM treatment. Taken together, the results demonstrate that miR-16 may serve as an effective chemosensitizing target to enhance the effects of chemotherapy in drug-resistant BC cells with high Wip1 and Bcl-2 expression. This provides a novel approach to improving the chemotherapeutic efficacy in drug-resistant BC via regulation of miRs.

miR-632 promotes gastric cancer progression by accelerating angiogenesis in a TFF1-dependent manner

Background

Gastric cancer (GC) is a common malignant disease worldwide. Aberrant miRNAs expression contributes to malignant cells behaviour, and in preclinical research, miRNA targeting has shown potential for improving GC therapy. Our present study demonstrated that miR-632 promotes GC progression in a trefoil factor 1 (TFF1)-dependent manner.

Methods

We collected GC tissues and serum samples to detect miR-632 expression using real-time PCR. A dual-luciferase reporter assay was used to identify whether miR-632 directly regulates TFF1 expression. Tube formation and endothelial cell recruitment assays were performed with or without miR-632 treatment. Western blot and in situ hybridization assays were performed to detect angiogenesis and endothelial recruitment markers that are affected by miR-632.

Results

Our results showed that miR-632 is highly expressed in GC tissue and serum and negatively associated with TFF1 in GC. miR-632 improves tube formation and endothelial cell recruitment by negatively regulating TFF1 in GC cells. Recombinant TFF1 reversed miR-632-mediated angiogenesis. TFF1 is a target gene of miR-632.

Conclusions

Our study demonstrated that miR-632 promotes GC progression by accelerating angiogenesis in a TFF1-dependent manner. Targeting of miR-632 may be a potential therapeutic approach for GC patients.

Electronic supplementary material

The online version of this article (10.1186/s12885-018-5247-z) contains supplementary material, which is available to authorized users.

Adipocytes induce distinct gene expression profiles in mammary tumor cells and enhance inflammatory signaling in invasive breast cancer cells

Obesity is a known risk factor for breast cancer. Since obesity rates are constantly rising worldwide, understanding the molecular details of the interaction between adipose tissue and breast tumors becomes an urgent task. To investigate potential molecular changes in breast cancer cells induced by co-existing adipocytes, we used a co-culture system of different breast cancer cell lines (MCF-7 and T47D: ER+/PR+/HER2- and MDA-MB-231: ER-/PR-/HER2-) and murine 3T3-L1 adipocytes. Here, we report that co-culture with adipocytes revealed distinct changes in global gene expression pattern in the different breast cancer cell lines. Our microarray data revealed that in both ER+ cell lines, top upregulated genes showed significant enrichment for hormone receptor target genes. In triple-negative MDA-MB-231 cells, co-culture with adipocytes led to the induction of pro-inflammatory genes, mainly involving genes of the Nf-κB signaling pathway. Moreover, co-cultured MDA-MB-231 cells showed increased secretion of the pro-inflammatory interleukins IL-6 and IL-8. Using a specific NF-κB inhibitor, these effects were significantly decreased. Finally, migratory capacities were significantly increased in triple-negative breast cancer cells upon co-culture with adipocytes, indicating an enhanced aggressive cell phenotype. Together, our studies illustrate that factors secreted by adipocytes have a significant impact on the molecular biology of breast cancer cells.

BQ323636.1, a Novel Splice Variant to NCOR2, as a Predictor for Tamoxifen-Resistant Breast Cancer

Purpose: Adjuvant tamoxifen treatment revolutionized the management of estrogen receptor (ER)-positive breast cancers to prevent cancer recurrence; however, drug resistance compromises its clinical efficacy. The mechanisms underlying tamoxifen resistance are not fully understood, and no robust biomarker is available to reliably predict those who will be resistant. Here, we study BQ323636.1, a novel splice variant of the NCOR2 gene, and evaluate its efficacy in predicting tamoxifen resistance in patients with breast cancer.Experimental Design: A monoclonal anti-BQ323636.1 antibody that specifically recognizes the unique epitope of this splice variant was generated for in vitro mechanistic studies and for in vivo analysis by immunohistochemistry on tissue microarrays of two independent cohorts of 358 patients with more than 10 years clinical follow-up data, who had ER-positive primary breast cancer and received adjuvant tamoxifen treatment. An orthotopic mouse model was also used.Results: Overexpression of BQ323636.1 conferred resistance to tamoxifen in both in vitro and in an orthotopic mouse model. Mechanistically, coimmunoprecipitation showed BQ323636.1 could bind to NCOR2 and inhibit the formation of corepressor complex for the suppression of ER signaling. Nuclear BQ3232636.1 overexpression in patients samples was significantly associated with tamoxifen resistance (P = 1.79 × 10^-6, sensitivity 52.9%, specificity 72.0%). In tamoxifen-treated patients, nuclear BQ323636.1 overexpression was significantly correlated with cancer metastasis and disease relapse. Nuclear BQ323636.1 was also significantly associated with poorer overall survival (P = 1.13 × 10^-4) and disease-specific survival (P = 4.02 × 10^-5).Conclusions: These findings demonstrate that BQ323636.1 can be a reliable biomarker to predict tamoxifen resistance in patients with ER-positive breast cancer. Clin Cancer Res; 24(15); 3681-91. ©2018 AACRSee related commentary by Jordan, p. 3480.

Extensive variation between tissues in allele specific expression in an outbred mammal

BACKGROUND

Allele specific gene expression (ASE), with the paternal allele more expressed than the maternal allele or vice versa, appears to be a common phenomenon in humans and mice. In other species the extent of ASE is unknown, and even in humans and mice there are several outstanding questions. These include; to what extent is ASE tissue specific? how often does the direction of allele expression imbalance reverse between tissues? how often is only one of the two alleles expressed? is there a genome wide bias towards expression of the paternal or maternal allele; and finally do genes that are nearby on a chromosome share the same direction of ASE? Here we use gene expression data (RNASeq) from 18 tissues from a single cow to investigate each of these questions in turn, and then validate some of these findings in two tissues from 20 cows.

RESULTS

Between 40 and 100 million sequence reads were generated per tissue across three replicate samples for each of the eighteen tissues from the single cow (the discovery dataset). A bovine gene expression atlas was created (the first from RNASeq data), and differentially expressed genes in each tissue were identified. To analyse ASE, we had access to unambiguously phased genotypes for all heterozygous variants in the cow's whole genome sequence, where these variants were homozygous in the whole genome sequence of her sire, and as a result we were able to map reads to parental genomes, to determine SNP and genes showing ASE in each tissue. In total 25,251 heterozygous SNP within 7985 genes were tested for ASE in at least one tissue. ASE was pervasive, 89 % of genes tested had significant ASE in at least one tissue. This large proportion of genes displaying ASE was confirmed in the two tissues in a validation dataset. For individual tissues the proportion of genes showing significant ASE varied from as low as 8-16 % of those tested in thymus to as high as 71-82 % of those tested in lung. There were a number of cases where the direction of allele expression imbalance reversed between tissues. For example the gene SPTY2D1 showed almost complete paternal allele expression in kidney and thymus, and almost complete maternal allele expression in the brain caudal lobe and brain cerebellum. Mono allelic expression (MAE) was common, with 1349 of 4856 genes (28 %) tested with more than one heterozygous SNP showing MAE. Across all tissues, 54.17 % of all genes with ASE favoured the paternal allele. Genes that are closely linked on the chromosome were more likely to show higher expression of the same allele (paternal or maternal) than expected by chance. We identified several long runs of neighbouring genes that showed either paternal or maternal ASE, one example was five adjacent genes (GIMAP8, GIMAP7 copy1, GIMAP4, GIMAP7 copy 2 and GIMAP5) that showed almost exclusive paternal expression in brain caudal lobe.

CONCLUSIONS

Investigating the extent of ASE across 18 bovine tissues in one cow and two tissues in 20 cows demonstrated 1) ASE is pervasive in cattle, 2) the ASE is often MAE but ranges from MAE to slight overexpression of the major allele, 3) the ASE is most often tissue specific and that more than half the time displays divergent allele specific expression patterns across tissues, 4) across all genes there is a slight bias towards expression of the paternal allele and 5) genes expressing the same parental allele are clustered together more than expected by chance, and there are several runs of large numbers of genes expressing the same parental allele.

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.

miR218-5p regulates the proliferation of gastric cancer cells by targeting TFF1 in an Erk1/2-dependent manner

Trefoil factor 1 (TFF1), a member of the trefoil peptide family, is not only associated with mucosal protection and restoration but is also correlated with tumorigenesis of the gastrointestinal tract. In an early study, we performed sequence analysis and identified one potential miR423-5p binding site within the 3'-untranslated region of TFF1 using microRNA target prediction tools. In the current study, we demonstrated that the coding DNA region within TFF1 is also a candidate for miR218-5p targeting. We used real-time PCR and in situ hybridization to analyze the correlation between miR218-5p and TFF1 expression in tumor lesions and paracancerous tissue in gastric cancer (GC) samples. Additionally, endogenous and exogenous TFF1 were suppressed by miR218-5p in gastric cancer cells and influenced the progression of GC in an Erk1/2-dependent manner. Targeting miR218-5p may provide a novel strategy for the treatment of GC.