The role of hsa_circ_0000520 in breast cancer progression: insights into the miR-542-3p/TMBIM6 regulatory axis.

HER2 is overexpressed in 20–25% of breast cancers. Overexpression of HER2 is an adverse prognostic factor and correlates with decreased patient survival. HER2 stimulates breast tumorigenesis via a number of intracellular signaling molecules, including PI3K/AKT and MAPK/ERK.S100A14,one member of the S100 protein family, is significantly associated with outcome of breast cancer patients. Here, for the first time, we show that S100A14 and HER2 are coexpressed in invasive breast cancer specimens,andthere is a significant correlation between the expression levels of the two proteins by immunohistochemistry. S100A14 and HER2 are colocalized in plasma membrane of breast cancer tissue cells and breast cancer cell lines BT474 and SK-BR3. We demonstrate that S100A14 binds directly to HER2 by co-immunoprecipitation and pull-down assays. Further study shows that residues 956–1154 of the HER2 intracellular domain and residue 83 of S100A14 are essential for the two proteins binding.Moreover,we observe a decrease of HER2 phosphorylation, downstream signaling, and HER2-stimulated cell proliferation in S100A14-silenced MCF-7, BT474, and SK-BR3 cells. Our findings suggest that S100A14 functions as a modulator of HER2 signaling and provide mechanistic evidence for its role in breast cancer progression.

Immunohistochemical expression of mTOR protein in breast carcinoma tissues

Breast cancer is known as one of very important cancers among females, given that a variety of external (i.e., environmental risk factors) and internal factors (i.e., genetics, and epigenetics) are related to the emergence and progression of breast cancer. Among genetic and epigenetic factors, DNA methyltransferase and EMT related genes have critical roles in breast cancer pathogenesis. In the study presented here, we investigated expression of DNA methyltransferases (e.g., DNMT1, DNMT3A and DNMT3B) and EMT related genes (e.g., E-cadherin, Snail, ZEB-1). Tissue samples were collected from 18 cancer and 24 normal breast tissues. We evaluated the expression levels of DNA methyltransferases and EMT related genes using Quantitative real-time PCR (qRT-PCR). Our results indicated that the expression levels of ZEB-1, Snail, and DNMT3B were increased in breast cancer subjects in comparison to the control group. On the other hand, there was a significant decrease in E-cadherin expression in breast cancer tissues in comparison to the normal tissues. Moreover, there were no significant changes for DNMT1 and DNMT3A expression in breast cancer tissues when compared to the normal tissues. Taken together, our finding show that up regulation of ZEB-1 and Snail could be associated with down regulation of E-cadherin and results in promotion of cancer cell invasion. Moreover, down regulation of E-cadherin may be related to deterioration of DNMT3B inpatients with breast cancer.

The purpose of this study was to analyze SUMO activating enzyme subunit 1 (SAE1) expression in breast cancer (BC). Through bioinformatics analysis and in vitro experiments, the biological function and possibly associated signal pathways of SAE1 in BC were further analyzed. Bioinformatics analysis was applied to analyze SAE1 expression in BC and normal breast tissues, its relationship with clinicopathologic characteristics and prognosis in BC patients, and data from the Cancer Genome Atlas database and Gene Expression Omnibus dataset. We performed immunohistochemistry to analyze SAE1 expression in BC tissues and para-cancer tissues in 79 breast cancer patients. BC cell proliferation was detected with the Cell Counting Kit-8 and by the colony formation assay. Cell cycle progression was analyzed by flow cytometry, and the expression of cell cycle-related proteins (E2F1, cyclin D3, and cyclin-dependent kinase 2) was determined by western blots in SAE1 small interfering RNA (siRNA) transfected cells. The GSE1456 dataset was used to analyze possible signal pathways associated with SAE1 by gene set enrichment analysis (GSEA), and the expression of PI3K/AKT/mTOR pathway-related proteins (such as p-PI3K, p-AKT, and mTOR) in SAE1-siRNA cells was detected by western blots. The bioinformatics and immunohistochemical results showed that SAE1 mRNA and protein expression in BC tissues were significantly higher than those in normal tissues. The SAE1 overexpression was significantly associated with the tumor size, tumor-node-metastasis stage, estrogen receptor, progesterone receptor, human epidermal growth factor receptor 2, and whether or not it was a triple-negative BC. Patients with SAE1 overexpression had a worse overall survival (OS), recurrence-free survival (RFS), and distant metastasis-free survival compared with lower expression patients. Multivariate Cox regression analysis showed that SAE1 may be an independent prognostic factor for OS of BC patients. The proliferation and cell cycle process of BC cells were inhibited by SAE1-siRNA in vitro. The result of GSEA showed that SAE1 was significantly associated with 12 gene sets, including unfolded protein reaction, DNA repair, oxidative phosphorylation, and cell cycle, among others. Additionally, two signal pathways, mTORC1 and PI3K/Akt/mTOR, were significantly correlated with SAE1 overexpression. Western blots confirmed that the expression of PI3K/Akt/mTOR pathway-related proteins (p-PI3K, p-AKT, and mTOR) in BC cells was decreased after knocking down SAE1. SAE1 was highly expressed in BC. Its overexpression was associated with poor BC prognosis. Additionally, it was an independent prognostic factor for BC patients. We demonstrated that in vitro SAE1 knockdown effectively inhibited BC proliferation and its cell cycle process. Furthermore, the biological function of SAE1 may be associated with the PI3K/Akt/mTOR pathway. SAE1 will be a potential target for BC treatment.

Background: Increasing evidence has demonstrated that microRNAs play a critical role in breast cancer (BC) progression. microRNA-101 (miR-101) has been considered a tumor suppressive miRNA in different cancer types. This study aimed to investigate miR-101 expression in BC tissues and to investigate its roles in BC progression that are mediated by Sex-determining region Y-box 2 (SOX2), a critical oncogene in various cancers. Methods: qRT-PCR and immunohistochemistry were performed to detect miR-101 and SOX2 expression in BC tissues and paired normal tissues or BC cell lines. MTT, transwell migration, wound healing, colony formation, flow cytometric and xenograft assays were performed to determine the influence of miR-101 and SOX2 on the malignant behaviors of BC cells in vitro and in vivo. Results: miR-101 was significantly downregulated in BC tissues and cell lines. miR-101 overexpression inhibited the malignant behaviors of BC cells, both in vitro and in vivo. miR-101 downregulation had the converse effect. A miR-101 binding site was identified by luciferase reporter assay in the 3’UTR of SOX2. SOX2 was upregulated in BC tissues and cell lines, and its upregulation was associated with lymph node metastasis, pathological grade and TNM classification. SOX2 knockdown mimicked the effects of miR-101 overexpression on the malignant behaviors of BC cells, while SOX2 overexpression mitigated the miR-101-induced inhibition of these effects. Conclusions: Our study revealed that miR-101 plays a critical role in suppressing tumor progression by directly targeting SOX2.

To explore the role of long intergenic non-coding ribonucleic acid 483 (LINC00483) in the development of breast cancer (BC) and its possible mechanism of action. LINC00483 expression level in BC tissues and cell lines was detected via quantitative Reverse Transcription-Polymerase Chain Reaction (qRT-PCR). The association between LINC00483 expression and survival rate of BC patients was analyzed using Kaplan-Meier survival analysis. The binding relation between LINC00483 and insulin-like growth factor 2 mRNA-binding protein 1 (IGF2BP1) was verified via RNA immunoprecipitation (RIP) and RNA pull-down assays. The expression of IGF2BP1 in BC patients was determined using qRT-PCR. Moreover, the role of LINC00483 on the proliferative ability of BC cells was detected via cell counting kit-8 (CCK8) and 5-Ethynyl-2'-deoxyuridine (EdU) assays. Whether LINC00483 exerts its effects under the regulation of IGF2BP1 was verified via reversal assay. The results of qRT-PCR showed that LINC00483 had a significantly high expression in BC tissues and corresponding cell lines, and it rose with the increase in tumor stage, which was higher in patients with metastasis. CCK8/EdU assay revealed that the proliferative ability of MDA-MB-231 and MCF-7 cell lines was enhanced by overexpression of LINC00483. It was confirmed by RIP and pull-down assays that IGF2BP1 could bind to LINC00483, and the expression of LINC00483 was significantly promoted after up-regulation of IGF2BP1. It was found via qRT-PCR that the expression of IGF2BP1 evidently rose in BC patients, which was positively related with the expression level of LINC00483. The results of reversal assay manifested that the function of LINC00483 on cell proliferation was regulated by IGF2BP1. LINC00483 has a significantly higher expression in BC tissues than that in para-carcinoma tissues, and its effect of promoting proliferation of BC cells may be regulated by IGF2BP1.

ABSTRACTTumor‐associated neutrophils (TANs) contribute to breast cancer (BC) progression, and aquaporin 9 (AQP9) plays a critical role in tumor development. However, the interactions between TANs and AQP9 in BC are poorly understood. Bioinformatics analyses and clinical samples revealed a positive correlation between neutrophil infiltration and AQP9 expression in BC. Treating BC cells with TAN‐conditioned media significantly elevated AQP9 expression compared with neutrophil‐conditioned and control media treatments. Immunohistochemical analysis revealed higher AQP9 protein expression in BC tissues than in adjacent normal tissues, and AQP9 expression was negatively correlated with recurrence‐free survival and overall survival in patients with BC. Functional studies demonstrated that AQP9 promoted BC cell proliferation but did not affect migration or invasion. AQP9 knockdown markedly inhibited the ability of TANs to enhance BC cell proliferation, migration, and invasion. Intravenous and intratumoral injection of TANs in mice increased tumor growth rate, weight, and volume compared with controls; moreover, histological examination revealed lung metastasis in two mice and bone involvement in one mouse out of six in the TAN treatment group. AQP9 knockdown significantly reduced the tumor growth rate. In BC cells, TAN treatment elevated STAT3 phosphorylation, and this effect was amplified by AQP9 overexpression. In conclusion, TANs promote BC progression by enhancing STAT3 phosphorylation through AQP9 upregulation. AQP9 is crucial for TAN‐mediated BC progression and is a potential target for immunotherapy in patients with BC.

The acceleration of Chemokine (C–C motif) ligand 18 (CCL18) and long noncoding RNA H19 expression is reportedly closely associated with breast cancer (BC) development and progression; however, the underlying mechanism and clinical value between CCL18 and H19 in BC remain unclear. Hence, this study aimed to examine the expression and function of CCL18 and H19 in BC tissues and cells by real-time polymerase chain reaction, immunohistochemistry, and other methods. We also detected the binding of EZH2 and other proteins to H19 through nanomagnetic bead immunoprecipitation and analyzed the roles of CCL18 and H19 in BC progression and their underlying mechanisms. Both CCL18 and H19 were upregulated in BC tissues and cell lines. High expression of CCL18 and EZH2 was closely associated with short survival in patients with BC. CCL18 or H19 silencing can prohibit BC cell invasion. Moreover, CCL18 accelerated the invasiveness of BC cells dose-dependently, and its expression was positively related to H19 expression in BC tissues. CCL18 enhanced H19 expression, while H19 knockdown partially ameliorated CCL18-induced BC cell invasiveness. Mechanistically, H19 can directly bind with EZH2 and mediate its accumulation at the promoter region of E-cadherin genes, consequently inhibiting E-cadherin expression. In conclusion, CCL18 promotes BC progression by enhancing H19 expression, and H19 overexpression suppresses E-cadherin expression via EZH2-mediated inhibition. Thus, this study describes a potential biomarker for the diagnosis, prognosis, and treatment of BC.

Exploring the Potential of Breast Microbiota as Biomarker for Breast Cancer and Therapeutic Response

BackgroundAlthough the number of circular RNAs (circRNAs) that has been identified in multiple cancer tissues continues to increase, the relationship between circRNA expression and carcinogenesis remains unknown. The role of hsa_circ_0072309 in breast cancer has remained undefined until now. In this study, we aimed to investigate the role of hsa_circ_0072309 in breast cancer progression.Methodshsa_circ_0072309 expression in breast cancer tissues was analyzed using qRT-PCR. A series of functional experiments were carried out to investigate hsa_circ_0072309 function in breast cancer development and its underlying molecular mechanisms.Resultshsa_circ_0072309 expression in breast cancer tissues was upregulated relative to that in adjacent normal tissues. hsa_circ_0072309 could serve as a prognostic biomarker of breast cancer. hsa_circ_0072309 overexpression dramatically inhibited the proliferation, migration, and invasion of breast cancer cells in vitro. In vivo assays revealed that the ectopic expression of hsa_circ_0072309 repressed breast cancer growth. The results of our mechanistic studies indicated that hsa_circ_0072309 could act as the sponge of miR-492, which exhibited increased expression in breast cancer tissues. Hsa_circ_0072309 suppressed breast cancer cell proliferation, migration, and invasion by inhibiting miR-492.ConclusionOur findings revealed for the first time that the hsa_circ_0072309-miR-492 axis plays an essential role in breast cancer progression.

Circular RNA (circRNA) has been confirmed to regulate breast cancer (BC) progression. However, the role of circ_0059457 in BC progression is still unclear.The expression of circ_0059457, taspase 1 (TASP1), microRNA (miR)-140-3p and ubiquitin-binding enzyme E2C (UBE2C) was detected by quantitative real-time PCR. Cell proliferation, migration, invasion and sphere formation ability were assessed by cell counting kit-8 assay, EdU assay, wound healing assay, transwell assay and sphere formation assay. Cell glycolysis was assessed by detecting glucose uptake, lactate levels and ATP/ADP ratio. Dual-luciferase reporter assay, RIP assay, RNA pull-down assay were used to validate RNA interaction. Xenograft tumor model to assess the effect of circ_0059457 on BC tumor growth in vivo. Circ_0059457 had elevated expression in BC tissues and cells. Circ_0059457 knockdown inhibited BC cell proliferation, metastasis, sphere formation ability, and glycolysis. In terms of mechanism, circ_0059457 sponged miR-140-3p, and miR-140-3p targeted UBE2C. MiR-140-3p inhibition reversed the effect of circ_0059457 knockdown on BC cell malignant behaviors. Besides, miR-140-3p overexpression inhibited BC cell proliferation, metastasis, sphere formation ability and glycolysis, and these effects were abrogated by UBE2C enhancement. Furthermore, circ_0059457 regulated UBE2C expression through sponging miR-140-3p. Additionally, circ_0059457 knockdown obviously inhibited BC tumor growth in vivo. Circ_0059457 promoted BC progression via miR-140-3p/UBE2C axis, which provided potential target for the treatment of BC.

PurposeThe aim of this study is to explore signal transducer and activator of transcription 3 (STAT3) expression in breast cancer and to analyze the detailed mechanism that STAT3 contributes to the progression of breast cancer.MethodsWe retrospectively analyzed the clinicopathologic characteristics and overall survival (OS) of 140 breast cancer patients after curative surgery, and detected STAT3 expression, phosphorylated STAT3 (pSTAT3) expression, Ki-67 expression, vascular endothelial growth factor (VEGF)-C and -D expression in breast cancer tissues, and adjacent nontumor tissues. Survival analysis and relationship analysis were adopted for demonstrated the important mechanism of STAT3 contribution to progression of breast cancer.ResultsSTAT3 expression, pSTAT3 expression, Ki-67 expression, VEGF-C expression, and VEGF-D expression in breast cancer tissues were significantly higher than those in adjacent nontumor tissues, respectively. With survival analysis, only number of lymph node metastasis (N stage) was identified as the independent predictors of the OS of breast cancer patients. Besides, we demonstrated there was the most prominent correlation between STAT3 expression and lymph node metastasis in breast cancer tissues by using the multinominal regression method.ConclusionSTAT3, a poor survival biomarker potential association with lymph node metastasis, was suitable for predication the OS of breast cancer patients after curative resection.

Epigenetic alterations have emerged as fundamental players in development and progression of breast cancer (BC). A hypoxic tumour microenvironment regulates the stemness phenotype in breast cancer stem cells (BCSCs). The aim of this study was to investigate Znhit1 and HIF-2α gene expression in breast cancer tissues as well as their relation to CSCs markers LGR5, ALDH1A1 and β-catenin in tissue and serum of BC patients. The present study included 160 females divided into two groups, group I: 80 healthy females served as control group and group II: 80 breast cancer patients. Gene expression of tissue Znhit1 and HIF-2α was determined by qRT-PCR. Tissue and serum ALDH1A1, LGR5 and β-catenin levels were determined by ELISA. We found that gene expression of Znhit1 was significantly downregulated in BC tissues. Moreover, it was significantly negatively correlated with clinical stage and β-catenin levels in BC patients. Regarding HIF-2α, gene expression of HIF-2α was significantly upregulated in BC tissues. Moreover, it was significantly positively correlated with Her-2/neu expression and β-catenin levels in BC patients. Based upon our results, Znhit1 and HIF-2α may serve as novel therapeutic targets for BC therapy. Additionally, each of serum ALDH1A1, LGR5 and β-catenin may play a crucial role in non-invasive detection of BC with a high specificity and sensitivity.

Phospholipid phosphatase 4 (PLPP4) has been identified as a potential regulator of cancer cell dynamics, however, the role of PLPP4 in breast cancer (BC) progression and the sensitivity of BC cells to doxorubicin (DOX) remain elusive. The study analyzed the expression of PLPP4 and cell cycle-associated protein 1 (CAPRIN1) expression in BC tissues and cells using quantitative real-time reverse transcription polymerase chain reaction (qRT-PCR) and western blotting assays. Functional assays including colony formation, EdU, Transwell, and flow cytometry were employed to assess cellular behaviors. The sensitivity of BC cells to DOX was analyzed by CCK-8 assay and an in vivo xenograft model assay. The association between PLPP4 and CAPRIN1 was investigated using RNA immunoprecipitation assay and dual-luciferase reporter assay. Upregulation of PLPP4 expression was observed in BC tissues and cells. Downregulation of PLPP4 expression in BC cells resulted in a suppression of their proliferative capacity, as well as a reduction in migratory and invasive capabilities. Additionally, this manipulation enhanced cell susceptibility to apoptosis and improved the sensitivity of these cells to DOX. When PLPP4 was knocked down in vivo in transplantable tumors, there was a marked enhancement in the responsiveness to DOX treatment. The transcription factor CAPRIN1 was found to regulate the expression of PLPP4 in the HCC1937 and MDA-MB-231 cell lines. Upregulation of CAPRIN1 was observed in both BC tissues and cells, and overexpression of PLPP4 reversed the effects of CAPRIN1 silencing on BC cell proliferation, migration, invasion, apoptosis, and DOX sensitivity. This study demonstrates that CAPRIN1 transcriptionally activates PLPP4 to inhibit DOX sensitivity and promote BC progression. Targeting PLPP4 may represent a novel therapeutic strategy to enhance the efficacy of DOX in BC patients.

Breast cancer is the second highest incidence of cancer in the world. It is of great significance to find biomarkers to diagnose breast cancer and predict the prognosis of breast cancer patients. PAIP2 is a poly (A) -binding protein interacting protein that regulates the expression of VEGF. However, the possible role of PAIP2 in the progression of breast cancer is still unknown. RT-qRCR and Western blotting were used to verify the expression of PAIP2 in breast cancer cells and normal breast cells. The data of breast cancer samples were obtained in the TCGA database and the HPA database to analyze the expression of PAIP2 in breast cancer samples. Transwell experiment and CCK8 experiment confirmed the changes in the invasion and proliferation ability of PAIP2 after siRNA was down-regulated. Using bioinformatics technology to explore the prognostic value of PAIP2 and its possible biological function, and its effect on tumor immunity and immunotherapy. Studies have shown that PAIP2 has higher expression in breast cancer tissues and breast cancer cells. PAIP2 can promote the proliferation and invasion of breast cancer cells and has significantly high expression in higher tumor stages. The high expression of PAIP2 is associated with better OS in breast cancer patients and is negatively correlated with most chemotherapeutic drug sensitivity and IPS in cancer immunotherapy. Our study explored the potential value of PAIP2 as a biomarker for diagnosis and prognosis and may predict the efficacy of immunotherapy, providing reference for the follow-up study on the role of PAIP2 in breast cancer.