Radiomics nomogram based on digital breast tomosynthesis: preoperative evaluation of axillary lymph node metastasis in breast carcinoma.

PURPOSE: This study aimed to establish a radiomics nomogram model based on digital breast tomosynthesis (DBT) images, to predict the status of axillary lymph nodes (ALN) in patients with breast carcinoma. METHODS: The data of 120 patients with confirmed breast carcinoma, including 49 cases with axillary lymph node metastasis (ALNM), were retrospectively analyzed in this study. The dataset was randomly divided into a training group consisting of 84 patients (37 with ALNM) and a validation group comprising 36 patients (12 with ALNM). Clinical information was collected for all cases, and radiomics features were extracted from DBT images. Feature selection was performed to develop the Radscore model. Univariate and multivariate logistic regression analysis were employed to identify independent risk factors for constructing both the clinical model and nomogram model. To evaluate the performance of these models, receiver operating characteristic (ROC) curve analysis, calibration curve, decision curve analysis (DCA), net reclassification improvement (NRI), and integrated discriminatory improvement (IDI) were conducted. RESULTS: The clinical model identified tumor margin and DBT_reported_LNM as independent risk factors, while the Radscore model was constructed using 9 selected radiomics features. Incorporating tumor margin, DBT_reported_LNM, and Radscore, the radiomics nomogram model exhibited superior performance with AUC values of 0.933 and 0.920 in both datasets, respectively. The NRI and IDI showed a significant improvement, suggesting that the Radscore may serve as a useful biomarker for predicting ALN status. CONCLUSION: The radiomics nomogram based on DBT demonstrated effective preoperative prediction performance for ALNM in patients with breast cancer.

Value of Histogram of Gray-Scale Ultrasound Image in Differential Diagnosis of Small Triple Negative Breast Invasive Ductal Carcinoma and Fibroadenoma.

Objective: To investigate the value of gray-scale ultrasound (US) image histogram in the differential diagnosis between small (≤2.00 cm), oval, or round triple negative breast invasive ductal carcinoma (TN-IDC) and fibroadenoma (FA). Methods: Fifty-five cases of triple negative breast invasive ductal carcinoma (TN-IDC group) and 57 cases of breast fibroadenoma (FA group) confirmed by pathology in Hubei cancer hospital from September 2017 to September 2021 were analyzed retrospectively. The gray-scale US images were analyzed by histogram analysis method, from which some parameters (including mean, variance, skewness, kurtosis and 1st, 10th, 50th, 90th and 99th percentile) can be obtained. Intraclass correlation coefficient (ICC) was used to evaluate the inter observer reliability of histogram parameters. Histogram parameters between the TN-IDC and FA groups were compared using independent Student's t-test or Mann-Whitney U-test, respectively. In addition, the receiver operating characteristic (ROC) curve analysis was used for the significant parameters to calculate the differential diagnosis efficiency. Results: All the histogram parameters showed excellent inter-reader consistency, with the ICC values ranged from 0.883 to 0.999. The mean value, 1st, 10th, 50th, 90th and 99th percentiles of TN-IDC group were significantly lower than those of FA group (P < 0.05). The area under ROC curve (AUC) values of mean and n percentiles were from 0.807 to 0.848. However, there were no significant differences in variance, skewness and kurtosis between the two groups (P > 0.05). Conclusion: Histogram analysis of gray-scale US images can well distinguish small, oval, or round TN-IDC from FA.

miR-363 Alleviates Detrusor Fibrosis via the TGF-ß1/Smad Signaling Pathway by Targeting Col1a2 in Rat Models of STZ-Induced T2DM.

Dysregulated expression of microRNAs (miRNAs or miRs) has been implicated in the pathophysiology of type 2 diabetes mellitus (T2DM). However, their underlying role in the complication of detrusor fibrosis remains poorly understood. Therefore, this study aimed to examine the potential functional relevance of miR-363 in detrusor fibrosis of rats with streptozotocin (STZ)-induced T2DM through the predicted target gene collagen type I alpha 2 (Col1a2). Immunohistochemical analysis found an increase in the positive expression of collagen type III alpha 1 (Col3a1) and Col1a2 in detrusor tissues, where miR-363 expression was decreased. Next, gain- and loss-of-function experiments were performed to clarify the effects of miR-363 and Col1a2 on the activities of bladder detrusor cells. Of note, binding affinity between miR-363 and Col1a2 was verified by a dual-luciferase reporter gene assay and RNA immunoprecipitation (RIP) assay. Upregulated miR-363 inhibited Col1a2 expression, which led to increased expression of B-cell lymphoma 2 (Bcl-2) and Smad7 and accelerated cell viability, along with decreases in cell apoptosis and Col3a1, Bcl-2-associated X protein (Bax), transforming growth factor (TGF)-ß1, and Smad4 expressions. In conclusion, miR-363 upregulation reduces detrusor fibrosis in rats with STZ-induced T2DM through suppression of the TGF-ß1/Smad signaling pathway by targeting Col1a2. Therefore, our study provided further insights for the development of new therapeutic targets for T2DM.

[Retracted] Diagnostic and prognostic value of contrast­enhanced ultrasound combined with diffusion­weighted magnetic resonance imaging in different subtypes of breast cancer.

Int J Mol Med 42: [Related article:] 105­114, 2018; DOI: 10.3892/ijmm.2018.3591. The authors have requested that their research article entitled 'Diagnostic and prognostic value of contrast­enhanced ultrasound combined with diffusion­weighted magnetic resonance imaging in different subtypes of breast cancer' published in International Journal of Molecular Medicine 42, 105­114, 2018, be retracted. This study was conceived jointly by the research institute of the authors' hospital (Jilin University China­Japan Friendship Hospital) and the Second Affiliated Hospital of Zhengzhou University, and the clinical data were obtained from the two institutes. It is regrettable that the scientific research unit of the Second Affiliated Hospital of Zhengzhou University did not authorize the publication of these results, and the authors have subsequently received an official request from the Second Affiliated Hospital of Zhengzhou University to retract this paper, since the results of their article have infringed the scientific research rights of the third party. The Editor of International Journal of Molecular Medicine agrees that the article should be retracted from the publication in view of the infringement of the scientific rights of the third party. All the named authors agree to this retraction. The authors apologize to the Editor and to the readership of the Journal, and regret any inconvenience this will cause.

Long non-coding RNA LINC00968 attenuates drug resistance of breast cancer cells through inhibiting the Wnt2/ß-catenin signaling pathway by regulating WNT2.

BACKGROUND: Breast cancer is one the most common cancers, making it the second leading cause of cancer-related death among women. Long non-coding RNAs (lncRNAs), with tightly regulated expression patterns, also serve as tumor suppressor during tumorigenesis. The present study aimed to elucidate the role of LINC00968 in breast cancer via WNT2-mediated Wnt2/ß-catenin signaling pathway. METHODS: Breast cancer chip GSE26910 was utilized to identify differential expression in LINC00968 and WNT2. The possible relationship among LINC00968, transcriptional repressor HEY and WNT2 was analyzed and then verified. Effects of LINC00968 on activation of the Wnt2/ß-catenin signaling pathway was also tested. Drug resistance, colony formation, cell migration, invasion ability and cell apoptosis after transfection were also determined. Furthermore, tumor xenograft in nude mice was performed to test tumor growth and weight in vivo. RESULTS: WNT2 expression exhibited at a high level, whereas LINC00968 at a low expression in breast cancer which was also associated with poor prognosis in patients. LINC00968 targeted and negatively regulated WNT2 potentially via HEY1. Either overexpressed LINC00968 or silenced inhibited activation of the Wnt2/ß-catenin signaling pathway, thereby reducing drug resistance, decreasing colony formation ability, as well as suppressing migration and invasion abilities of breast cancer cells in addition to inducing apoptosis. Lastly, in vivo experiment suggested that LINC00968 overexpression also suppressed transplanted tumor growth in nude mice. CONCLUSION: Collectively, overexpressed LINC00968 contributes to reduced drug resistance in breast cancer cells by inhibiting the activation of the Wnt2/ß-catenin signaling pathway through silencing WNT2. This study offers a new target for the development of breast cancer treatment.

Analgesic effects of microRNA-129-5p against bone cancer pain through the EphB1/EphrinB2 signaling pathway in mice.

The study aims to investigate the analgesic effects of microRNA-129-5p (miR-129-5p) on bone cancer pain (BCP) by targeting Eph receptor B1 (EphB1) through the EphB1/EphrinB2 signaling pathway. BCP mice models were established, and C3H/HeJ female mice were classified into the normal, blank, negative control (NC), miR-129-5p mimics, miR-129-5p inhibitors, EphB1 knockout (KO), and miR-129-5p inhibitors + EphB1 KO groups. Quantitative reverse transcription polymerase chain reaction and Western blot analysis were used to evaluate the miR-129-5p expression, and messenger RNA (mRNA) and protein expressions of EphB1, p-EphB1, EphrinB2, and p-EphrinB2. EphB1 and EphrinB2 were highly activated in the tibias of BCP mice 7 days after the operation. EphB1 is a target gene of miR-129-5p. The mechanical withdrawal threshold increased in the miR-129-5p mimics, EphB1 KO and miR-129-5p inhibitors + EphB1 KO groups, but decreased in the miR-129-5p inhibitors group. Compared with the blank and the NC groups, the expression of miR-129-5p was significantly increased in the miR-129-5p mimics group, and the mRNA and protein expressions of EphrinB2, p-EphrinB2, EphB1, and p-EphB1 were significantly decreased, while in the miR-129-5p inhibitors group, the results were opposite (all P < 0.05); the mRNA and protein expressions of EphrinB2, p-EphrinB2, EphB1, and p-EphB1 were significantly decreased in the EphB1 KO group (all P < 0.05); the expression of miR-129-5p was significantly decreased in the miR-129-5p inhibitors + EphB1 KO group ( P < 0.05), while the mRNA and protein expressions of EphrinB2 and p-EphrinB2 were not significantly different ( P > 0.05). The results indicated that upregulated miR-129-5p alleviate BCP via downregulation of the EphB1/EphrinB2 signaling pathway.

Efficacy and adverse events of five targeted agents in the treatment of advanced or metastatic non-small-cell lung cancer: A network meta-analysis of nine eligible randomized controlled trials involving 5,059 patients.

Recently, targeted agents were reported to improve overall survival, progression-free survival (PFS), response rate, and quality of life compared with cytotoxic chemotherapies, which provides hope for the treatment of non-small-cell lung cancer (NSCLC). The network meta-analysis is applied to compare the efficacies and adverse events of five targeted agents (erlotinib, gefitinib, vandetanib, dacomitinib, and icotinib) for advanced or metastatic NSCLC. Nine eligible randomized controlled trials from PubMed and Cochrane Library database were included. Weighted mean difference, odds ratio, and surface under the cumulative ranking curve (SUCRA) values were evaluated for the efficacy and adverse events of the five targeted agents in the treatment of NSCLC. With regard to efficacy, the overall response rate (ORR) of advanced or metastatic NSCLC patients treated with gefitinib was relatively higher than those treated with placebo. Compared with patients treated with placebo, the disease control rate (DCR) of patients treated with erlotinib and with gefitinib was relatively higher. Furthermore, in terms of PFS and DCR, the SUCRA value of icotinib was the highest among the five targeted drugs. With regard to ORR, the SUCRA value of gefitinib was the highest among the five targeted drugs. In terms of fatigue, rash, and cough, erlotinib had the lowest SUCRA value, whereas vandetanib exhibited the lowest SUCRA value in terms of diarrhea. Our study suggests that the efficacies of gefitinib and icotinib for advanced or metastatic NSCLC were comparatively better, whereas the toxicities of erlotinib and vandetanib were relatively greater.

Downregulation of the long noncoding RNA MBNL1-AS1 protects sevoflurane-pretreated mice against ischemia-reperfusion injury by targeting KCNMA1.

Total knee arthroplasty (TKA) is the most common and cost-effective treatment for older adults with long-standing osteoarthritis. During TKA, muscle cells suffer from prolonged oxygen deficiency, which leads to altered cell metabolism that reduces the energy demand and maintains cell homeostasis before blood flow is restored. This study focused on the role of the lncRNA muscleblind-like 1 antisense RNA 1 (MBNL1-AS1) in protecting sevoflurane-pretreated mice against ischemia-reperfusion (I/R) injury after TKA, as well as the elucidation of the potential associated mechanism. Identification of differentially expressed lncRNAs was performed using the microarray dataset GSE21164, which was extracted from the GEO database. Target genes of the lncRNA were determined using Multi-Experiment Matrix (MEM), a dual-luciferase reporter gene assay, and KEGG enrichment analyses. The results showed that MBNL1-AS1 was overexpressed in skeletal muscle cells in mice, while KCNMA1, which was enriched in the cGMP-PKG signaling pathway, was negatively regulated by MBNL1-AS1. Furthermore, I/R mice displayed serious inflammatory reactions. Down-regulation of MBNL1-AS1 increased the expression of KCNMA1, PKGII, VASP, VEGF, Bcl-2, Cyclin D1, Cyclin D3, and Cdc 42 but decreased the expression of Bax, cleaved caspase-3, and cleaved PARP. Furthermore, upon MBNL1-AS1 upregulation, the rate of cell apoptosis increased while the rate of cell proliferation decreased. Our data suggested that down-regulated lncRNA MBNL1-AS1 might promote the proliferation and inhibit the apoptosis of skeletal muscle cells by upregulating KCNMA1 expression via activation of the cGMP-PKG signaling pathway, thus protecting sevoflurane-pretreated mice against I/R injury after TKA.

Diagnostic and prognostic values of contrast­enhanced ultrasound combined with diffusion­weighted magnetic resonance imaging in different subtypes of breast cancer.

The present study aimed to investigate the diagnostic and prognostic values of contrast­enhanced ultrasound (CEUS) combined with diffusion­weighted magnetic resonance imaging (DW­MRI) in different subtypes of breast cancer (BC). CEUS and DW­MRI were conducted in 232 patients with BC prior to surgical treatment. Patients were categorized as having the luminal A subtype, the luminal B subtype, triple­negative subtype or the human epidermal growth factor receptor 2 (Her­2)­positive subtype according to their expression of the estrogen receptor (ER), progesterone receptor (PR) and Her­2, as detected by immunohistochemistry. The CEUS and DW­MRI parameters of patients with different subtypes of BC were obtained and analyzed. The risk factors for the prognosis of patients with different subtypes of BC were analyzed using Kaplan­Meier and COX regression analyses. The diagnostic accuracy rate of CEUS combined with DW­MRI (93.10%) was higher than that of CEUS (88.79%) or DW­MRI (82.33%) alone. The local recurrence rate and distant metastasis rate of the Her­2­positive subtype were the highest among all the subtypes. Furthermore, patients with Her­2­positive BC exhibited a higher proportion of lesions with indistinct margins and histological grade III. Lymph node metastasis and BC subtype were independent risk factors for the prognosis of BC. The overall survival and disease­free survival of patients with the luminal A subtype were higher than those of patients with the Her­2­positive subtype. The results of the current study therefore indicate that CEUS combined with DW­MRI is more effective at diagnosing the different subtypes of BC than either CEUS or DW­MRI alone.

Efficacy of different chemotherapy regimens in treatment of advanced or metastatic pancreatic cancer: A network meta-analysis.

We performed a network meta-analysis (NMA) to compare the short- and long-term efficacy of Gemcitabine, Gemcitabine + S-1 (tegafur), Gemcitabine + nab-paclitaxel, Gemcitabine + Capecitabine, Gemcitabine + Cisplatin, FOLFIRINOX (oxaliplatin + irinotecan + fluorouracil + leucovorin), Gemcitabine + oxaliplatin, Gemcitabine + irinotecan, Gemcitabine + Exatecan, Gemcitabine + pemetrexed, Gemcitabine + 5-FU, and S-1 in treating advanced or metastatic pancreatic cancer (PC). The odds radios (OR) or weighted mean difference (WMD) and surface under the cumulative ranking curves (SUCRA) were evaluated by a combination of direct evidence and indirect evidence. In total twenty studies were included in this paper. For short-term efficacy, the overall response rate (ORR) was lower for patients treated with Gemcitabine compared with Gemcitabine + S-1, Gemcitabine + Cisplatin, Gemcitabine + irinotecan and S-1. The ORR for FOLFIRINOX was higher compared with Gemcitabine, Gemcitabine + Capecitabine and Gemcitabine + Cisplatin. The disease control rate (DCR) for Gemcitabine was lower compared with Gemcitabine + S-1, Gemcitabine + Cisplatin, and FOLFIRINOX. For long-term efficacy, the 12-month overall survival (OS) rate for FOLFIRINOX was higher compared with Gemcitabine, Gemcitabine + Capecitabine, Gemcitabine + Cisplatin, Gemcitabine + irinotecan, Gemcitabine + Exatecan, and Gemcitabine + pemetrexed. The SUCRA revealed that FOLFIRINOX was relatively better in both short- and long-term efficacy, while Gemcitabine was relatively poorer. In both short- and long-term efficacy, FOLFIRINOX had the best short- and long-term efficacy among the 12 chemotherapy regimens while efficacy of Gemcitabine was relatively poorer in the treatment of advanced or metastatic PC.

Overexpression of microRNA-132 enhances the radiosensitivity of cervical cancer cells by down-regulating Bmi-1.

We examined the effects of microRNA-132 (miR-132) on Bmi-1 expression and radiosensitivity in HeLa, SiHa, and C33A cervical cancer (CC) cells and 104 CC patients. MiR-132 expression was decreased and Bmi-1 expression was increased in tumor tissues compared to adjacent normal tissues and in radiotherapy-resistant patients compared to radiotherapy-sensitive patients. MiR-132 expression and Bmi-1 mRNA expression were also negatively correlated in tumor tissues. HeLa, SiHa, and C33A cells were divided into blank, miR-132 negative control (NC), miR-132 inhibitor, miR-132 mimics, siBmi-1, and miR-132 inhibitor + siBmi-1 groups, after which expression of miR-132 and Bmi-1, and the interaction between them and cell survival, proliferation, and apoptosis were examined. Bmi-1 was confirmed as a target of miRNA-132. Survival was higher and apoptosis lower in the miR-132 inhibitor group than the blank group after various doses of radiation. By contrast, survival was lower and apoptosis higher in the miRNA-132 mimics and siBmi-1 groups than in the blank group. Moreover, miR-132 expression increased and Bmi-1 mRNA expression decreased in each group at radiation doses of 6 and 8 Gy. Finally, co-administration of radiotherapy and exogenous miR-132 inhibited the growth of HeLa cell transplant-induced tumors in nude mice more effectively than radiotherapy alone. These results suggest overexpression of miR-132 enhances the radiosensitivity of CC cells by down-regulating Bmi-1 and that miR-132 may be a useful new target for the treatment of CC.

Evaluation of Prediction of Polymorphisms of DNA Repair Genes on the Efficacy of Platinum-Based Chemotherapy in Patients With Non-Small Cell Lung Cancer: A Network Meta-Analysis.

This network meta-analysis (NMA) was conducted to compare the predictive value of 14 SNPs in eight DNA repair genes on the efficacy of platinum-based chemotherapy in patients with non-small cell lung cancer (NSCLC). These included ERCC1 (rs11615, rs3212986, rs3212948), XRCC1 (rs25487, rs25489, rs1799782), XPD (rs13181, rs1799793), XPG (rs1047768, rs17655), XPA (rs1800975), XRCC3 (rs861539), APE1 (rs3136820), and RRM1 (rs1042858). The PubMed and Cochrane library databases were reviewed from their inception to February 2017 and studies which met our inclusion criteria were included in our investigation. This network meta-analysis combines direct and indirect evidence to assess the predictive value of 14 SNPs in eight DNA repair genes on the efficacy of platinum-based chemotherapy in NSCLC. We evaluated the predictive value through the use of the odd ratios (OR) and drawing surface under the cumulative ranking curves (SUCRA). A total of 26 eligible cohort studies were enrolled in this NMA. The pairwise meta-analysis indicated that in terms of overall response ratio (ORR), ERCC1 (rs11615), XRCC1 (rs25487, rs1799782), and XPD (rs13181) polymorphisms are associated with the efficacy of platinum-based chemotherapy in NSCLC. The result of this NMA suggests that there is no significant difference in predictive value of 8 DNA repair genes on the efficacy of platinum-based chemotherapy in NSCLC patients. The rank of SUCRA values of the 14 SNPs in the eight DNA repair genes were: XPD (rs1799793)→ERCC1 (rs3212986)→XPA(rs1800975)→ERCC1(rs3212948)→XRCC1(rs25487)→XRCC3(rs861539)→APE1(rs3136820)→ERCC1(rs11615)→XRCC1(rs1799782)→RRM1(rs1042858)→XPD(rs13181)→XPG (rs1047768)→XPG(rs17655)→XRCC1(rs25489). ERCC1(rs11615), XRCC1(rs25487, rs1799782) and XPD(rs13181) polymorphisms were better predictors in evaluating the efficacy of platinum-based chemotherapy in NSCLC patients. J. Cell. Biochem. 118: 4782-4791, 2017. © 2017 Wiley Periodicals, Inc.

Chitosan nanoparticle-delivered siRNA reduces CXCR4 expression and sensitizes breast cancer cells to cisplatin.

Chemokine (C-X-C motif) receptor 4 (CXCR4) has been reported as a poor prognostic biomarker in human breast cancers, and has been suggested as a promising therapeutic target of breast cancer treatment. The present study aims to investigate the delivery efficiency of siRNA by chitosan into breast cancer cells, and then to examine the regulatory role by chitosan nanoparticle-delivered siRNA on CXCR4 expression and on the chemosensitivity of breast cancer cells. Our results demonstrated that the siRNA could be capsuled by chitosan into nanoparticles with a diameter of 80-110 nm, and with a zeta potential of 20-50 mV. The chitosan nanoparticle delivered siRNA efficiently into breast cancer MCF-7 cells significantly reduced the expression of CXCR4 in both mRNA and protein levels. Moreover, the reduced CXCR4 by chitosan nanoparticle-delivered siRNA was associated with increased sensitivity of breast cancer cells to cisplatin. Reduced growth and increased apoptosis of MCF-7 cells were observed in the CXCR4 siRNA group than in the control siRNA group. Taken together, our results present the treatment potential of chitosan nanoparticle-delivered siRNA targeting CXCR4 in breast cancers.

MicroRNAs contribute to promyelocyte apoptosis in As2O3-treated APL cells.

BACKGROUND: Arsenic trioxide (As2O3), an ancient drug used in traditional Chinese medicine, has substantial anticancer activities, especially in the treatment of patients suffering from acute promyelocytic leukemia (APL); however the underlying mechanisms are not well understood. METHODS: MTT assay was used to detect the cell viability. Flow Cytometry analysis and caspase-3 activity assay were used to measure apoptosis of APL cells. Caspase-3 and Bax levels were analyzed by western blot and let-7d and miR-766 levels were determined by real-time RT-PCR. RESULTS: As2O3 significantly inhibited cell viability and induced apoptosis in APL cells. Several microRNAs, including let-7d and miR-766, were dysregulated in APL cells treated with As2O3. The expression of caspase-3 and Bax, which are targets of let-7d and miR-766, respectively, were up-regulated in As2O3 treated cells. Transfection of let-7d and miR-766 into NB4 cells decreased the expression of caspase-3 and Bax, respectively. Correspondingly, transfection of these microRNAs increased NB4 cell viability. As2O3 induced degradation of promyelocytic leukemia (PML), and then induced the down-regulation of both let-7d and miR-766 in NB4 cells. CONCLUSIONS: We construct a dysregulated microRNA network involved in As2O3-induced apoptosis in APL. Targeting this network may be a new strategy for the prevention of side effects associated with APL treatment with As2O3.

High level of CXCR4 in triple-negative breast cancer specimens associated with a poor clinical outcome.

Despite high sensitivity to chemotherapy, the prognosis for triple-negative breast cancer (TNBC) remains poor because of its high rate of metastasis and low sensitivity to endocrine therapy. CXCR4 expression has been reported in many subtypes of human breast cancers, but it remains unknown whether CXCR4 is expressed in TNBC and whether CXCR4 expression in TNBC could be a prognostic indicator. TNBCs tissues were formalin fixed, paraffin embedded and hematoxylin-eosin (H&E) stained. Immunohistochemical staining was utilized to determine the CXCR4 expression in those specimens. Statistical analyses were performed using SPSS16.0 software to reveal the correlation of CXCR4 expression in TNBC specimens and cancer recurrence and cancer-related death. Our results showed that there was a strong association between CXCR4 overexpression and both menopause and the histological cancer grade of TNBC patients (p values were separately 0.004 and 0.001). The 5-y disease-free survival (DFS) and the 5-y overall survival (OS) were 57.69% and 58.33% for the low-CXCR4 group versus 42.11% and 44.74% for the high-CXCR4 group, respectively (p＝0.031 and 0.048). CXCR4 overexpression plays an important role in triple-negative breast cancers, and may be a predictor of poor prognosis.

Downregulation of miR-151-5p contributes to increased susceptibility to arrhythmogenesis during myocardial infarction with estrogen deprivation.

Estrogen deficiency is associated with increased incidence of cardiovascular diseases. But merely estrogen supplementary treatment can induce many severe complications such as breast cancer. The present study was designed to elucidate molecular mechanisms underlying increased susceptibility of arrhythmogenesis during myocardial infarction with estrogen deprivation, which provides us a new target to cure cardiac disease accompanied with estrogen deprivation. We successfully established a rat model of myocardial ischemia (MI) accompanied with estrogen deprivation by coronary artery ligation and ovariectomy (OVX). Vulnerability and mortality of ventricular arrhythmias increased in estrogen deficiency rats compared to non estrogen deficiency rats when suffered MI, which was associated with down-regulation of microRNA-151-5p (miR-151-5p). Luciferase Reporter Assay demonstrated that miR-151-5p can bind to the 3'-UTR of FXYD1 (coding gene of phospholemman, PLM) and inhibit its expression. We found that the expression of PLM was increased in (OVX+MI) group compared with MI group. More changes such as down-regulation of Kir2.1/IK1, calcium overload had emerged in (OVX+MI) group compared to MI group merely. Transfection of miR-151-5p into primary cultured myocytes decreased PLM levels and [Ca(2+)]i, however, increased Kir2.1 levels. These effects were abolished by the antisense oligonucleotides against miR-151-5p. Co-immunoprecipitation and immunofluorescent experiments confirmed the co-localization between Kir2.1 and PLM in rat ventricular tissue. We conclude that the increased ventricular arrhythmias vulnerability in response to acute myocardial ischemia in rat is critically dependent upon down-regulation of miR-151-5p. These findings support the proposal that miR-151-5p could be a potential therapeutic target for the prevention of ischemic arrhythmias in the subjects with estrogen deficiency.