Carcinogenesis Of Breast Cancer Research Articles

Knockdown of E2F5 induces cell death via the TP53‑dependent pathway in breast cancer cells carrying wild‑type TP53.

E2F transcription factor 5 (E2F5) is a member of the E2F family of transcription factors, which are involved in regulation of various cellular processes, including cellular proliferation, apoptosis, differentiation and DNA damage response. Previously, we reported that E2F5 was aberrantly overexpressed in estrogen receptor (ER)‑negative breast cancer, especially in triple‑negative breast cancer (TNBC). In the present study, it was revealed that E2F5 gene silencing caused a significant reduction in the proliferation rate of breast cancer MCF7 (ER‑positive luminal‑type) and MDA‑MB‑231 (TNBC‑type) cells. Additional experiments demonstrated that E2F5 knockdown triggered cell death of MCF7 cells but not MDA‑MB‑231 cells. As MCF7 and MDA‑MB‑231 cells carry wild‑type and mutant TP53, respectively, and BT474 (ER‑negative, HER2‑positive type) carrying mutant TP53 exhibited similar results to MDA‑MB‑231, the possible effects of E2F5 gene depletion on cell death‑related TP53‑target gene expression were examined. Real‑time RT‑qPCR analysis revealed that knockdown of E2F5 in MCF7 cells stimulated cell death‑related transcription of TP53‑target genes such as BAX, NOXA and PUMA. For MDA‑MB‑231 and BT474 cells, E2F5 gene silencing revealed marginal effects on the expression of TP53 target genes. In addition, silencing of TP53 abrogated the effect of E2F5 silencing in MCF7 cells. Collectively, the present results indicated that E2F5 participated in the carcinogenesis of breast cancer carrying wild‑type TP53 through suppression of TP53, while E2F5 had a pro‑proliferative but not anti‑apoptotic effect on breast cancer with TP53 mutation.

Analysis of key genes and pathways in breast ductal carcinoma in situ.

Breast cancer (BC) remains the most common cancer in females. Therefore, the present study aimed to identify key genes involved in the carcinogenesis of BC and to explore their prognostic values by integrating bioinformatics tools. The gene expression profiles of 46 ductal carcinoma in situ (DCIS) and three normal breast tissues from the GSE59248 dataset were downloaded. Differentially expressed genes (DEGs) were subsequently identified using the online tool GEO2R and a functional enrichment analysis was performed. In addition, a protein-protein interaction (PPI) network was constructed and the top eight hub genes were identified. The prognostic values of the hub genes were further investigated. A total of 316 DEGs, including 32 upregulated and 284 downregulated genes, were identified. Furthermore, eight hub genes, including lipase E hormone sensitive type, patatin like phospholipase domain containing 2, adiponectin C1Q and collagen domain containing (ADIPOQ), peroxisome proliferator activated receptor γ (PPARG), fatty acid binding protein 4 (FABP4), diacylglycerol O-acyltransferase 2, lipoprotein lipase (LPL) and leptin (LEP), were identified from the PPI network. The downregulated expression of ADIPOQ, PPARG, FABP4, LPL and LEP was significantly associated with poor overall survival in patients with DCIS. Therefore, these genes may serve as potential biomarkers for prognosis prediction. However, further investigation is required to validate the results obtained in the present study.

Screening of key modulatory genes by Degalactotigonin in Triple Negative Breast Cancer cells – An in silico approach

Breast cancer is one of the world’'s most prevalent malignant tumors among women. This is currently classified according to the expression of the receptor. Triple Negative Breast Cancer (TNBC) results poorly because of the lack of therapeutic targets. A challenge for researchers is to control effective and safer chemotherapeutic agents that target specific biochemical processes involved in cancer growth. New drug development in cancer research is one of the leading fields that have concentrated on the synthesis of new therapeutic agents that specifically target particular core cancer progression molecules. Therefore we focused on the compound Degalactotigonin in Triple Negative Breast Cancer cells in silico studies. The online software Gene Expression Omnibus (GEO) database helps to analyze the microarray datasets and identify key modulatory genes by comparing TNBC and Non-TNBC cells. In this current study, we collected three microarray data sets using GEO online tool. The integrated analyzes were conducted using three datasets namely GSE65194, GSE61724 and GSE38959 has 209 TNBC patient samples and 42 Non – TNBC patient samples. Evaluations of three data sets (9 down-regulated genes and 22 up-regulated genes in TNBC cells) were found to be expressed differently. The scrutinized genes were docked; some valuable evidence for the forthcoming design of more efficient inhibitors was provided in the docking results. This research result will provide enhanced understandings of Triple Negative Breast Cancer's carcinogenesis and can contribute to the production of molecular targets as a treatment for TNBC patients.

Mendelian randomization analyses of genetically predicted circulating levels of cytokines with risk of breast cancer

To determine whether genetically predicted circulating levels of cytokines are associated with risk of overall breast cancer (BC), estrogen receptor (ER)-positive and ER-negative BC, we conducted two-sample MR analyses using data from the most comprehensive genome-wide association studies (GWAS) on cytokines in 8293 Finnish participants and the largest BC GWAS from the Breast Cancer Association Consortium (BCAC) with totally 122,977 BC cases and 105,974 healthy controls. We systematically screened 41 cytokines (of which 24 cytokines have available instruments) and identified that genetically predicted circulating levels (1-SD increase) of MCP1 (OR: 1.08; 95% CIs: 1.03–1.12; P value: 3.55 × 10−4), MIP1b (OR: 1.02; 95% CIs: 1.01–1.04; P value: 2.70 × 10−3) and IL13 (OR: 1.06; 95% CIs: 1.03–1.10; P value: 3.33 × 10−4) were significantly associated with increased risk of overall BC, as well as ER-positive BC. In addition, higher levels of MIP1b and IL13 were also significantly associated with increased risk of ER-negative BC. These findings suggest the crucial role of cytokines in BC carcinogenesis and potential of targeting specific inflammatory cytokines for BC prevention.

Abstract 4613: Cross-ancestry genome-wide association study identifies six new loci for breast cancer in women of African and european ancestry

Abstract Background: Over 180 genetic variants have been identified as risk loci for breast cancer. However, most loci were discovered using European ancestry populations. As some common susceptibility loci are shared across populations, we aim to discover new risk loci for breast cancer using a cross-ancestry genome-wide association study (GWAS) approach. Methods: Data from five GWAS studies in women of African ancestry with a combined sample size of 9241 cases and 10192 controls were used to generate pooled breast cancer risk estimates in a fixed effect meta-analysis, and this served as the discovery dataset. Summary statistics from the GWAS conducted in European ancestry populations (Breast Cancer Association Consortium, 122977 cases and 105974 controls) served as the validation dataset. The variants that were associated with breast cancer risk at P < 0.01 in the GWAS of African ancestry were meta-analyzed with the GWAS in European ancestry. A locus was considered novel if the lead index variant was genome-wide significant (5 × 10−8) in the cross-ancestry meta-analysis and >500kb away from known breast cancer risk loci. Conditional on the lead index variants, we searched for additional signals in each locus using multivariable logistic regression. Analyses were done separately for ER-positive, ER-negative and overall breast cancer risk. Results: We discovered four novel loci for overall breast cancer risk (1p13.3, 5q31.1, 15q24, and 15q26.3) and two novel loci for ER-negative breast cancer (1q41 and 7q11.23) at the genome-wide significance level of P < 5 × 10−8. Three index single nucleotide polymorphism (SNPs) lie within introns of genes (KCNK2, C5orf56, and SIN3A) and the other index SNPs are located in intergenic regions (close to GSTM4 and AMPD2, CASTOR2, and the antisense DNA RP11-168G16.2). The direction of the associations was consistent between the GWASs of African and European descendants. At the 15q24 locus, we found an additional SNP (in the intron of the SCAMP2 gene) to be independently associated with overall breast cancer risk. Conclusions: We have identified six new risk loci that may contribute to better prediction of breast cancer risk in African ancestry populations and provide new insights into mechanisms of breast cancer carcinogenesis. Replication of these loci in multiple populations and functional studies can help to identify causal variants. Citation Format: Babatunde Adedokun, Zhaohui Du, Guimin Gao, Thomas Ahearn, Kathryn L. Lunetta, Gary Zirpoli, Jonine Figueroa, Esther M. John, Leslie Bernstein, Wei Zheng, Jennifer J. Hu, Regina G. Ziegler, Sarah Nyante, Elisa V. Bandera, Sue A. Ingles, Michael F. Press, Sandra L. Deming, Jorge L. Rodriguez-Gil, Song Yao, Temidayo O. Ogundiran, Oladosu Ojengbede, William Blot, Melissa Troester, Katherine L. Nathanson, Anselm Hennis, Barbara Nemesure, Stefan Ambs, Lara E. Sucheston-Campbell, Jeannette T. Bensen, Stephen J. Chanock, Andrew F. Olshan, Christine B. Ambrosone, David V. Conti, Olufunmilayo I. Olopade, Montserrat Garcia-Closas, Julie R. Palmer, Christopher A. Haiman, Dezheng Huo. Cross-ancestry genome-wide association study identifies six new loci for breast cancer in women of African and european ancestry [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 4613.

FEATURES OF RAT THYMUS MORPHOLOGY AT THE INDUCTION OF THE BREAST CANCER BY N-METHYL-N-NITROSOUREA

The immune system as a whole plays a leading role in the formation of an adequate immune response during the onset and development of tumors. The aim of the study was to reveal the features of the change in the morphology and level of biogenic amines of the thymus of rats during experimental carcinogenesis of breast cancer by the injection of N-methyl-N-nitrosourea. In the work used luminescence-histochemical, general histological and immunohistochemical methods, which made it possible to obtain important information about the functional activity of the cellular elements of the thymus, the quantitative composition of macrophages, dendritic cells, lymphocytes and the qualitative characteristics of mast cells. The experiment was carried out on 85 white nonlinear female rats, which were injected with the carcinogen N-methyl-N-nitrosourea, which induces a breast tumor. Animals were divided into two groups: intact (n=30) and rats injected with a carcinogen (n=45). The thymus structure was examined 1, 2, and 3 months after the end of the injections. During the study, changes in the morphometric parameters of the organ are noted. A month after the injection of the drug, the area of the medulla of the thymus and the thickness of the cortex substance of the organ increases, which decrease with an increase in the study period. Replacement of the thymus parenchyma with adipose and connective tissue begins after 2 months and progresses with an increase in the study period. A tendency to wavelike changes in biogenic amines was revealed, after 1 month there is a significant increase in the level of histamine and a decrease in serotonin and catecholamines, after 2 months an increase in all biogenic amines, especially histamine (1.5 times or more) in premedullary and mast cells, thymocytes of the cortex. After 3 months, on the contrary, there is a decrease in histamine and an increase in the level of monoamines. The ratio (serotonin+histamine)/catecholamines after 1 month indicate a decrease in the functional activity of the thymus, and after 3 months - about its increase. At all stages of the study, degranulated forms of mast cells predominate. In the dynamics of the experiment, an increase in the number of dendritic cells, lymphocytes, and twice the number of macrophages and Bcl-2+cells was revealed. The data obtained in the course of the study suggested that the introduction of N-methyl-N-nitrosourea and the subsequent development of a breast tumor is reflected in the change in the morphofunctional state of the thymus. In this case, the greatest changes were observed 2 months after the end of the administration of the carcinogen, even before the formation of a breast tumor. The data obtained can have a certain value in determining the immune status in models of experimental carcinogenesis.

ABC-GWAS: Functional Annotation of Estrogen Receptor-Positive Breast Cancer Genetic Variants.

Over the past decade, hundreds of genome-wide association studies (GWAS) have implicated genetic variants in various diseases, including cancer. However, only a few of these variants have been functionally characterized to date, mainly because the majority of the variants reside in non-coding regions of the human genome with unknown function. A comprehensive functional annotation of the candidate variants is thus necessary to fill the gap between the correlative findings of GWAS and the development of therapeutic strategies. By integrating large-scale multi-omics datasets such as the Cancer Genome Atlas (TCGA) and the Encyclopedia of DNA Elements (ENCODE), we performed multivariate linear regression analysis of expression quantitative trait loci, sequence permutation test of transcription factor binding perturbation, and modeling of three-dimensional chromatin interactions to analyze the potential molecular functions of 2,813 single nucleotide variants in 93 genomic loci associated with estrogen receptor-positive breast cancer. To facilitate rapid progress in functional genomics of breast cancer, we have created “Analysis of Breast Cancer GWAS” (ABC-GWAS), an interactive database of functional annotation of estrogen receptor-positive breast cancer GWAS variants. Our resource includes expression quantitative trait loci, long-range chromatin interaction predictions, and transcription factor binding motif analyses to prioritize putative target genes, causal variants, and transcription factors. An embedded genome browser also facilitates convenient visualization of the GWAS loci in genomic and epigenomic context. ABC-GWAS provides an interactive visual summary of comprehensive functional characterization of estrogen receptor-positive breast cancer variants. The web resource will be useful to both computational and experimental biologists who wish to generate and test their hypotheses regarding the genetic susceptibility, etiology, and carcinogenesis of breast cancer. ABC-GWAS can also be used as a user-friendly educational resource for teaching functional genomics. ABC-GWAS is available at http://education.knoweng.org/abc-gwas/.

A Polymorphism at the microRNA Binding Site in the 3′ Untranslated Region of KRT81 Is Associated with Breast Cancer

Single nucleotide polymorphisms in miRNA binding sites (miR-SNPs) are associated with cancer risk. We assessed the relationship between five miR-SNPs in the 3' untranslated region (3'-UTR) of RYR3 (rs1044129), KIAA0423 (rs1053667), C14orf101 (rs4901706), GOLGA7 (rs11337), and KRT81 (rs3660) and the risk of breast cancer (BC). The CC genotype of rs3660 located in the 3'-UTR of KRT81 was identified for its association with lower BC risk (odds ratio, 0.093; 95% confidence interval, 0.045-0.193; p = 0.000). Immunnochemical analysis and Renilla luciferase reporter assays indicated that the CC genotype of KRT81 was associated with lower expression of KRT81 (p < 0.05). The subsequently functional analysis showed that knockdown the KRT81 could inhibit proliferation and promote apoptosis of the MDA-MB-231 BC cells (p < 0.05) with monocyte chemotactic protein-1 (MCP-1) deregulation. Meanwhile, KRT81 overexpression could promote the proliferation and inhibit the apoptosis of MCF-7 BC cells (p < 0.05). Our data demonstrated that the KRT81 expressional change modulated by rs3660 miR-SNP could modify the carcinogenesis of BC, thereby KRT81 would be a new target for BC treatment.

Subtype-specific risk models for accurately predicting the prognosis of breast cancer using differentially expressed autophagy-related genes.

Emerging evidence suggests that the dysregulation of autophagy-related genes (ARGs) is coupled with the carcinogenesis and progression of breast cancer (BRCA). We constructed three subtype-specific risk models using differentially expressed ARGs. In Luminal, Her-2, and Basal-like BRCA, four- (BIRC5, PARP1, ATG9B, and TP63), three- (ITPR1, CCL2, and GAPDH), and five-gene (PRKN, FOS, BAX, IFNG, and EIF4EBP1) risk models were identified, which all have a receiver operating characteristic > 0.65 in the training and testing dataset. Multivariable Cox analysis showed that those risk models can accurately and independently predict the overall survival of BRCA patients. Comprehensive analysis showed that the 12 identified ARGs were correlated with the overall survival of BRCA patients; six of the ARGs (PARP1, TP63, CCL2, GAPDH, FOS, and EIF4EBP1) were differentially expressed between BRCA and normal breast tissue at the protein level. In addition, the 12 identified ARGs were highly interconnected and displayed high frequency of copy number variation in BRCA samples. Gene set enrichment analysis suggested that the deactivation of the immune system was the important driving force for the progression of Basal-like BRCA. This study demonstrated that the 12 ARG signatures were potential multi-dimensional biomarkers for the diagnosis, prognosis, and treatment of BRCA.

Identification of serum exosomal miR-148a as a novel prognostic biomarker for breast cancer.

Breast cancer (BC) is one of the most common malignanciesD. Li, J. Wang, L.-J. Ma, H.-B. Yang, J.-F. Jing, M.-M. Jia, X.-J. Zhang, F. Guo, J.-N. Gao affecting females. Aberrant expression of microRNAs (miRNAs) has been associated with carcinogenesis of BC. The aim of our study was to investigate the correlation of serum exosomal miR-148a expression and the clinical outcome of patients with BC. Quantitative Real Time-Reverse Transcription Polymerase Chain Reaction (qRT-PCR) was applied to evaluate the expression level of serum exosomal miR-148a in patients with BC, patients with benign breast tumors, and healthy controls. Then, the clinical value of serum exosomal miR-148a in BC was evaluated. Serum exosomal miR-148a levels were gradually downregulated from healthy controls patients with benign breast tumors to BC patients. Serum exosomal miR-148a could well distinguish BC patients from healthy volunteers. The expression level of serum exosomal miR-148a in BC patients was significantly upregulated following surgery, while dropped in the cases with disease relapse. A significant association was found between serum exosomal miR-148a levels and the tumor-node-metastasis (TNM) stage, differentiation, and lymph node metastasis in BC. In addition, BC patients with lower expression of serum exosomal miR-148a levels suffered worse overall survival and disease-free survival than those with higher expression of serum exosomal miR-148a levels. Furthermore, serum exosomal miR-148a was an independent risk factor for BC. Our data have demonstrated that serum exosomal miR-148a is significantly reduced in patients with BC and downregulation of serum exosomal miR-148a is closely associated with unfavorable clinical outcome of BC, indicating that serum exosomal miR-148a might serve as a promising diagnostic and prognostic biomarker for BC.

MicroRNA and their role in pathogenesis and diagnosis of breast cancer

This article discusses the mechanisms of the influence of microRNAs on carcinogenesis in breast cancer (breast cancer), their potential role as markers for the early detection, prognosis and effectiveness of breast cancer treatment. Epigenetic mechanisms of regulation of miсroRNA expression and their indirect effect on the pathogenesis of the disease are described.

Role of regulatory miRNAs of the Wnt/ β-catenin signaling pathway in tumorigenesis of breast cancer.

Breast cancer is the most commonly diagnosed malignancy in women worldwide. Recently, uncontrolled expression of microRNAs was detected in several human disorders like cardiovascular, neurological, intestinal and autoimmunity diseases. MicroRNAs (miRNAs) are now investigated as novel prognostic and diagnostic biomarkers for several solid tumors like breast, lung, and gastrointestinal cancers. Current data suggest that miRNAs are implicated in various oncogenic processes implicated in breast cancer carcinogenesis trough modulating canonical Wnt pathway. Aberrant activation of Wnt/b-catenin signaling was shown to be significantly associated with tumor progression and poor prognosis in patients with breast cancer. This review presents recent findings on the molecular mechanism of microRNAs in regulation of Wnt/β-catenin signaling involved in tumorigenesis of breast cancer.

The circRNA circSEPT9 mediated by E2F1 and EIF4A3 facilitates the carcinogenesis and development of triple-negative breast cancer

BackgroundIncreasing studies have shown that circRNA is closely related to the carcinogenesis and development of many cancers. However, biological functions and the underlying molecular mechanism of circRNAs in triple-negative breast cancer (TNBC) remain largely unclear so far.MethodsHere, we investigated the expression pattern of circRNAs in four pairs of TNBC tissues and paracancerous normal tissues using RNA-sequencing. The expression and prognostic significance of circSEPT9 were evaluated with qRT-PCR and in situ hybridization in two TNBC cohorts. The survival curves were drawn by the Kaplan-Meier method, and statistical significance was estimated with the log-rank test. A series of in vitro and in vivo functional experiments were executed to investigate the role of circSEPT9 in the carcinogenesis and development of TNBC. Mechanistically, we explored the potential regulatory effects of E2F1 and EIF4A3 on biogenesis of circSEPT9 with chromatin immunoprecipitation (ChIP), luciferase reporter and RNA immunoprecipitation (RIP) assays. Furthermore, fluorescent in situ hybridization (FISH), luciferase reporter and biotin-coupled RNA pull-down assays were implemented to verify the relationship between the circSEPT9 and miR-637 in TNBC.ResultsIncreased expression of circSEPT9 was found in TNBC tissues, which was positively correlated with advanced clinical stage and poor prognosis. Knockdown of circSEPT9 significantly suppressed the proliferation, migration and invasion of TNBC cells, induced apoptosis and autophagy in TNBC cells as well as inhibited tumor growth and metastasis in vivo. Whereas up-regulation of circSEPT9 exerted opposite effects. Further mechanism research demonstrated that circSEPT9 could regulate the expression of Leukemia Inhibitory Factor (LIF) via sponging miR-637 and activate LIF/Stat3 signaling pathway involved in progression of TNBC. More importantly, we discovered that E2F1 and EIF4A3 might promote the biogenesis of circSEPT9.ConclusionsOur data reveal that the circSEPT9 mediated by E2F1 and EIF4A3 facilitates the carcinogenesis and development of triple-negative breast cancer through circSEPT9/miR-637/LIF axis. Therefore, circSEPT9 could be used as a potential prognostic marker and therapeutical target for TNBC.

The effect of smoking on biological change of recurrent breast cancer

BackgroundThe selection of treatment for a patient with breast cancer largely relies on the cancer subtype. However, this process is complicated by changes in tumor biology at relapse. Smoking has been identified as a risk factor for breast cancer. The direct effect of a tobacco component delivered via blood circulation on the mammary gland tissue and subsequent DNA damage have been proposed to explain the association between cigarette smoking and breast cancer carcinogenesis. This postulation is supported by both tissue culture and animal studies demonstrating that the associated DNA damage further alters breast cancer cells, as indicated by an increased proliferative capacity and malignant transformation. In this study, we aimed to explore the relationship between changes in Estrogen receptor (ER), progesterone receptor (PgR), and human epidermal growth factor receptor 2 (HER2) each receptor at recurrence, and smoking and the prognosis after recurrence.MethodsThis retrospective study included 989 patients with primary breast cancer who developed relapse after surgery and 50 patients who underwent regenerative biopsy or surgery from December 2007 to March 2018. ER, PgR, and HER2 expression in the primary and recurrent lesions was evaluated using immunohistochemistry, and the correlations of these expression patterns with smoking history (pack-years) were examined.ResultsWhen ER was evaluated in recurrent tumors, negative and positive conversions were recognized in 3 (6.0%) and 1 patient (2.0%), respectively. When PgR was evaluated, negative conversion was recognized in 15 patients (30.0%). When HER2 was evaluated, positive conversion was recognized in 6 patients (12.0%). Consequently, we observed a change in the intrinsic subtype in in 5 patients with recurrent tumors (10.0%). Although most clinical factors were not correlated with smoking, a positive conversion of HER2 in recurrence was significantly more frequent among smokers than among non-smokers (p = 0.024).ConclusionsBiological changes during breast cancer recurrence should be given careful clinical consideration because they affect treatment after recurrence. Our results suggest that smoking may induce increased HER2 expression in recurrent breast tumors.

Abstract P2-04-02: Progesterone receptor membrane component 1 - A novel key regulator in lipid homeostasis drives oncogenic signaling resulting in breast cancer progression

Abstract Background: PGRMC1 (progesterone receptor membrane component 1) is a highly conserved heme binding protein which is overexpressed especially in hormone receptor positive breast cancer and plays an important role in breast cancer carcinogenesis. Nevertheless, little is known about the mechanisms by which PGRMC1 drives tumor progression. Based on our previous studies on the involvement of PGRMC1 in cholesterol metabolism we describe a potential mechanism by which PGRMC1 can increase lipid metabolism and alter EGFR signaling. Methods: To obtain PGRMC1 overexpressing cell lines, MCF7, T47D and MDA cells were stably transfected with expression plasmid pcDNA3.1. containing HA-tagged PGRMC1. As a control, cells transfected with the empty plasmid were used.To investigate the role of PGRMC1 in breast cancer progression, expression of genes involved in lipid metabolism were quantified by qPCR. Subsequent lipid and cholesterol levels as well as lipid raft expression were measured by flow cytometry in various breast cancer cell lines overexpressing PGRMC1 compared to empty vector control. Since many studies show that EGFR is enriched in lipid rafts, we further investigated alteration of EGFR/HER2 signaling through PGRMC1 overexpression via western blot and immunofluorescence analyses. The impact of lipid inhibition on tumor progression was analyzed by viability assays. Results: PGRMC1 overexpression resulted in higher levels of mRNA coding for proteins responsible for lipid homeostasis (SREPF1, SREBF2), lipid uptake (LDLR) and lipid synthesis (FASN, HMGCS, SCD, ACAT) leading to higher levels of neutral lipids, estradiol and cholesterol. Furthermore, PGRMC1 overexpressing hormone receptor positive cells show increased lipid raft formation with higher expression of EGFR/HER2 and altered EGFR/HER2 signaling. PGRMC1 overexpressing cells are more sensitive to a simvastatin treatment, which indicates a higher dependence of PGRMC1 overexpressing cells on cholesterol synthesis. Conclusion: Cholesterol and lipid metabolism play an important role in breast carcinogenesis. Our recent studies underline the effects of PGRMC1 on increasing lipid synthesis and uptake thereby altering oncogenic signaling. PGRMC1 overexpressing breast cancer cells could be particularly suitable for a statin treatment. Citation Format: Hannah Asperger, Marina Ludescher, Nadia Stamm, Jan-Philipp Cieslik, Ute Hofmann, Ulrich Zanger, Zaklina Kovacevic, Des Richardson, Eugen Ruckhäberle, Tanja Fehm, Dieter Niederacher, Hans Neubauer. Progesterone receptor membrane component 1 - A novel key regulator in lipid homeostasis drives oncogenic signaling resulting in breast cancer progression [abstract]. In: Proceedings of the 2019 San Antonio Breast Cancer Symposium; 2019 Dec 10-14; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2020;80(4 Suppl):Abstract nr P2-04-02.

ROR2 promotes the epithelial-mesenchymal transition by regulating MAPK/p38 signaling pathway in breast cancer.

Receptor tyrosine kinase-like orphan receptor 2 (ROR2) is a tyrosine-protein kinase receptor highly implicated in the growth plate and cartilage development, which may be involved in epithelial-mesenchymal transition (EMT) in breast cancer (BC) cells. Although ROR2 is known to promote the migration of BC cells, the detailed mechanism of this event is still not clear. Here, we found that ROR2 expression was significantly increased in BC lymphatic metastatic tissue as well as BC samples compared to normal adjacent breast tissues. A higher expression of ROR2 in MDA-MB-231 and a lower expression of ROR2 in MCF-7 cells were observed. MDA-MB-231-siROR2 cells with ROR2 knockdown inhibited MDA-MB-231 cell invasion, migration, and clonal formation, while MCF-7-OvROR2 cells with overexpression showed the opposite results. The underlying mechanisms involved in ROR2-induced EMT in MDA-MB-231 and MCF-7 cells were further investigated. ROR2 may activate EMT progression in BC cells by altering MAPK kinase 3/6 (MKK3/6) expression. The expressions of transforming growth factor-β, matrix metalloproteinase-2 (MMP-2), and MMP-9, which were related to tumor cell invasion activities, were notably increased in MCF-7-OvROR2 cells. The EMT markers, including snail, N-cadherin, tissue inhibitor of metalloproteinases-1, and vimentin, were significantly upregulated in MCF-7-OvROR2 cells. On the contrary, E-cadherin was obviously reduced expressed in MCF-7-OvROR2 cells. ROR2 may regulate the malignant phenotype of BC cells possibly via activation of mitogen-activated protein kinase (MAPK)/p38 signaling pathway. Collectively, ROR2 promotes BC carcinogenesis by mediating the MAPK/p38 pathway, which is independent of Wnt5α.

Circular RNA-0001283 Suppresses Breast Cancer Proliferation and Invasion via MiR-187/HIPK3 Axis.

BackgroundCircular RNAs (circRNAs) are key regulators that take part in the carcinogenesis and development of breast cancer. The current study aimed to identify the expression of and explored the function of circRNA-0001283 in breast cancer.Material/MethodsBreast cancer tissue samples were tested using high-throughput sequencing to identify the levels of relative genes; and proteins were addressed by using quantitative real-time polymerase chain reaction (qRT-PCR) and western-blot. Cell ability and cell apoptosis were investigated by Cell Counting Kit-8 (CCK-8) and flow cytometry. Invasion was detected by Transwell invasion assay. The identification of target genes was analyzed by dual-luciferase reporter assay.ResultDownregulation of circRNA-0001283 expression was observed in breast cancer tissue samples. Ectopic expression of circRNA-0001283 remarkably suppressed cell viability and invasion, and induced apoptosis in breast cancer cells. Furthermore, circRNA-0001283 bound to miR-187 and decreased the expression of miR-187, which resulted in inhibition in cell growth and invasion. Finally, we showed that circRNA-0001283 positively regulated HIPK3 expression by sponging miR-187.ConclusionsThe results reveal a new functional circRNA-0001283 in breast cancer and may provide targets for developing novel therapeutic strategies for breast cancer.

Effects of HOX transcription antisense RNA on carcinogenesis and development of triple-negative breast cancer

Objective To investigate the significance of HOX transcription antisense RNA (HOTAIR) expression in triple-negative breast cancer (TNBC) and explore the molecular modulation of HOTAIR on the progression of TNBC. Methods Sixty-four human TNBC tissues and their corresponding non-tumor tissues were collected, and the HOTAIR levels were detected by real-time quantitative polymerase chain reaction (Real-time PCR). The different HOTAIR levels in tumor and non-tumor tissues were compared. And then we analyzed its significance in TNBC with different pathological stages. In MDA-MB231 cells, the effects of down-regulation of HOTAIR by small interfering RNA (siRNA) on the proliferation (MTT) and apoptosis (Western blotting) were detected. The effects of down-regulation of HOTAIR on the expression of enhancer of zeste homolog2 (EZH2), the enzymatic subunit of ploycomb repressor complex (PRC2), were detected. SPSS19.0 statistical software was used for analysis. Results Compared with the non-tumor tissues, the HOTAIR expression was significantly increased in TNBC tumors (0.71±0.10 vs. 0.50±0.06, t=20.286, P<0.01), especially in TNBC with advanced stage (0.78±0.05 vs. 0.64±0.07, t=8.625, P<0.01). In TNBC cells, treatment of siEZH2 showed similar effects on the cell proliferation and apoptosis. In TNBC cells, EZH2 expression was down-regulated by siHOTAIR. However, HOTAIR expression had no significant change after siEZH2 treatment. Conclusion HOTAIR is highly expressed in TNBC and associated with poor prognosis. Our results suggest HOTAIR may induce the carcinogenesis in TNBC probably through regulating EZH2. Key words: Triple negative breast cancer; HOX transcription antisense RNA; Enhancer of zeste homolog 2

MicroRNA-769-5p suppresses cell growth and migration via targeting NUSAP1 in bladder cancer.

BackgroundNucleolar and spindle‐associated protein 1 (NUSAP1) has been identified to be strongly implicated in the carcinogenesis of cervical carcinoma, breast cancer, and liver cancer, and shows a high expression level in bladder cancer, indicating that NUSAP1 might be a potent target for cancer treatment. Using bioinformatics methods, we found that NUSAP1 was a putative target of miR‐769‐5p. Here, we aimed to explore whether miR‐769‐5p is involved in bladder cancer progression via targeting NUSAP1.MethodsMiR‐769‐5p expression patterns in bladder cancer tissues and cells were detected by RT‐PCR. Kaplan‐Meier was used to determine the clinical effects of miR‐769‐5p expression levels on the overall survival of bladder cancer patients. Bioinformatics methods were used to predict the binding sites between miR‐769‐5p and NUSAP1, which was verified by the luciferase gene reporter assay. CCK‐8, flow cytometry, wound healing and transwell chamber experiments were performed to test cell growth, apoptosis, migration and invasion capacities.ResultsmiR‐769‐5p was lowly expressed in bladder cancer tissues and cells, which was closely associated with poor prognosis. Overexpression of miR‐769‐5p induced significant repressions in cell growth, migration, and invasion and caused an obvious increase in cell apoptosis, whereas these tendencies were reversed when NUSAP1 was upregulated.ConclusionThis study demonstrates that miR‐769‐5p functions as a tumor suppressor in bladder cancer via targeting NUSAP1.

Effect of SALL4 on the Proliferation, Invasion and Apoptosis of Breast Cancer Cells.

Objective:We aimed to identify the expression of Sal-like 4 (SALL4) in breast cancer tissues and to explore the role of this gene in the carcinogenesis of breast cancer cells.Methods:A total of 62 paired breast cancer and noncancerous tissue samples were obtained from patients with breast cancer. SALL4 expression patterns and their association with clinicopathological characteristics were investigated by qRT-PCR, western blotting, and immunochemistry in breast cancer tissues. After the knockdown of SALL4 by short hairpin RNAs (shRNAs), the proliferative, invasive, and apoptotic abilities of MDA-MB-435 and MDA-MB-468 cells (breast cancer cell lines) were measured by colony formation and CCK-8 assays, wound healing and transwell assays, and flow cytometry, respectively.Results:SALL4 expression was higher in breast cancer tissues than that in the paired noncancerous tissues, and increased SALL4 expression in tumor tissues was closely related to tumor size and lymphatic metastasis. Furthermore, functional experiments revealed that SALL4 knockdown inhibited the cell proliferation, induced cell cycle arrest in G0/G1phase and apoptosis, and decreased the ability of migration and invasion in breast cancer cells. Additionally, our study first demonstrated that SALL4 played a critical role in modulating the tumorigenicity of breast cancer cells via the WNT/β-catenin signaling pathway.Conclusions:Our results suggest that the expression of SALL4 is upregulated in breast cancer, and this upregulation is involved in the regulation of cell growth, invasion, and apoptosis. Hence, SALL4 may be a promising target for diagnosis and therapy in patients with breast cancer.