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Trastuzumab is commonly used in the treatment of human epidermal growth factor receptor-2 positive (HER-2+) breast cancer, but its efficacy is often limited by the emergence of chemoresistance. Recent studies indicate that exosomes act as vehicles for exchange of genetic cargo between heterogeneous populations of tumor cells, engendering a transmitted drug resistance for cancer development and progression. However, the specific contribution of breast cancer-derived exosomes is poorly understood. In this study, publicly available expression profiling data from breast cancer and bioinformatics analyses were used to screen potential miRNAs in trastuzumab resistance. A series of gain- or loss-functional assays were performed to define the function of miR-567 and ATG5 in trastuzumab resistance and autophagy, both in vitro and in vivo. Our results showed that miR-567 was significantly decreased in trastuzumab-resistant patients compared with responding patients. Moreover, miR-567 was also downregulated in trastuzumab-resistant cells compared with parental cells. Overexpression of miR-567 reversed chemoresistance, whereas silence of miR-567 induced trastuzumab resistance, both in vitro and in vivo. In addition, enhanced miR-567 could be packaged into exosomes, incorporated into receipt cells, suppressing autophagy and reversed chemoresistance by targeting ATG5. To conclude, exosomal miR-567 plays a key role in reversing trastuzumab resistance via regulating autophagy, indicating it may be a promising therapeutic target and prognostic indicator for breast cancer patients.

Background Long non-coding RNA (lncRNA) is an endogenous RNA over 200 nt in length involved in gene regulation. LINC01559 is a novel lncRNA that has been identified as a fundamental player in human cancer. However, its role in triple-negative breast cancer (TNBC) remains unknown. Here, we explored the expression, function and clinical implication of LINC01559 in TNBC. Methods RNA expression was detected by qRT-PCR analysis. Cell Counting Kit-8 (CCK-8), 5-Ethynyl-2′-deoxyuridine (EdU), wound healing and Transwell assays were used to test cell viability, DNA synthesis rate, migration and invasion, respectively. The competing endogenous RNA (ceRNA) axis involved in LINC01559 was determined by RNA pull-down and luciferase reporter assays. The xenograft model was used to verify the function of LINC01559 in vivo. Results LINC01559 was significantly increased in TNBC tissues as compared to matched normal tissues, which was due to high levels of H3K4Me3 and H3K27Ac in the promoter region. Knockdown of LINC01559 inhibited TNBC cell proliferation, migration and invasion in vitro, and also retarded tumor growth and reduced lung metastasis in vivo. Mechanistically, LINC01559 served as a ceRNA that sponged miR-370-3p, miR-485-5p and miR-940, resulting in increasing the expression of a cohort of oncogenes, thus accelerating TNBC progression. Conclusions Our data provide a comprehensive analysis of LINC01559 in TNBC, we found that LINC01559 functioned as a carcinogenic ceRNA via sponging miRNAs. Targeting of LINC01559 may be a potential treatment for TNBC patients.

Trastuzumab has been widely used for treatment of HER-2-positive breast cancer patients, however, the clinical response has been restricted due to emergence of resistance. Recent studies indicate that long noncoding RNA AGAP2-AS1 (lncRNA AGAP2-AS1) plays an important role in cancer resistance. However, the precise regulatory function and therapeutic potential of AGAP2-AS1 in trastuzumab resistance is still not defined. In this study, we sought to reveal the essential role of AGAP2-AS1 in trastuzumab resistance. Our results suggest that AGAP2-AS1 disseminates trastuzumab resistance via packaging into exosomes. Exosomal AGAP2-AS1 induces trastuzumab resistance via modulating ATG10 expression and autophagy activity. Mechanically, AGAP2-AS1 is associated with ELAVL1 protein, and the AGAP2-AS1-ELAVL1 complex could directly bind to the promoter region of ATG10, inducing H3K27ac and H3K4me3 enrichment, which finally activates ATG10 transcription. AGAP2-AS1-targeting antisense oligonucleotides (ASO) substantially increased trastuzumab-induced cytotoxicity. Clinically, increased expression of serum exosomal AGAP2-AS1 was associate with poor response to trastuzumab treatment. In conclusion, exosomal AGAP2-AS1 increased trastuzumab resistance via promoting ATG10 expression and inducing autophagy. Therefore, AGAP2-AS1 may serve as predictive biomarker and therapeutic target for HER-2+ breast cancer patients.

The regulatory mechanism of long non-coding RNAs (lncRNAs) in trastuzumab resistance is not well established to date. In this research, we identified differentially expressed lncRNA and investigated its regulatory role in trastuzumab resistance of breast cancer. HiSeq sequencing and quantitative real-time PCR were performed to identify the dysregulated lncRNAs. Mass spectrometry, RNA fluorescence in situ hybridization (RNA-FISH), and immunoprecipitation assays were performed to identify the direct interactions between ZNF649-AS1 and other associated targets, such as polypyrimidine tract binding protein 1 (PTBP1) and autophagy related 5 (ATG5). Our results showed that ZNF649-AS1 was more highly expressed in trastuzumab-resistant cells compared to sensitive cells. Increased expression of ZNF649-AS1 was associated with a poorer response and shorter survival time of breast cancer patients. ZNF649-AS1 was upregulated by H3K27ac modification at the presence of trastuzumab treatment, and knockdown of ZNF649-AS1 reversed trastuzumab resistance via modulating ATG5 expression and autophagy. Mechanically, ZNF649-AS1 was associated with PTBP1 protein, which further promoted the transcription activity of the ATG5 gene. In conclusion, we demonstrated that H3K27ac modification-induced upregulation of ZNF649-AS1 could cause autophagy and trastuzumab resistance through associating with PTBP1 and promoting ATG5 transcription.

Background: Trastuzumab has been widely used for treatment of HER-2-positive breast cancer patients, however, the clinical response has been restricted due to emergence of resistance. Recent studies indicate that long noncoding RNA AGAP2-AS1 (lncRNA AGAP2-AS1) plays an important role in cancer resistance. However, the precise regulatory function and therapeutic potential of AGAP2-AS1 in trastuzumab resistance is still not defined. Methods: Trastuzumab resistant cells were established. RNA sequencing and qRT-PCR were performed to identify the target gene of AGAP2-AS1. Mass spectrometry, RNA pulldown and RNA immunoprecipitation assays were performed to verify the direct interactions among AGAP2-AS1 and other associated targets, such as embryonic lethal abnormal version like RNA binding protein 1 (ELAVL1) and autophagy related 10 (ATG10). In vitro and in vivo experimental assays were done to clarify the functional role of exosomal AGAP2-AS1 in trastuzumab resistance.Results: AGAP2-AS1 promotes and disseminates trastuzumab resistance via packaging into exosomes. Exosomal AGAP2-AS1 induces trastuzumab resistance via modulating ATG10 expression and autophagy activity. Mechanically, AGAP2-AS1 is associated with ELAVL1 protein. The AGAP2-AS1-ELAVL1 complex could directly bind to the promoter region of ATG10, inducing H3K27ac and H3K4me3 enrichment, which finally activates ATG10 transcription. AGAP2-AS1-targeting antisenseoligonucleotides (ASO) substantially increased trastuzumab-induced cytotoxicity. Clinically, increased expression of serum exosomal AGAP2-AS1 was associate with poor response to trastuzumab treatment.Conclusion: ExosomalAGAP2-AS1 increased trastuzumab resistance via promoting ATG10 expression and inducing autophagy. Therefore, AGAP2-AS1 may serve aspredictive biomarker and therapeutic target for HER-2+ breast cancer patients.

Additional file 7: Figure S3 Nuclear fraction experiment and qRT-PCR experiments were performed to detect the relative distribution of AFAP1-AS1 in nuclear and cytoplasm of SKBR-3 and BT474 cells.

Additional file 2: Table S2 Information of the qPCR primer sequences and silencing RNA sequences.

Additional file 1: Table S1 Clinical characteristics of 64 HER2+ patients and the expression of AFAP1-AS1.

Additional file 8: Table S4 Identification of AFAP1-AS1 binding proteins by MS.

Additional file 4: Table S3 Univariate and multivariate Cox proportional hazards regression model analysis of overall survival in breast cancer patients.

Additional file 6: Figure S2 HER-2 protein was upregulated in trastuzumab-resistant cells. (a) Quantification of fluorescence intensity of Fig. 6a. (b-d) Flow cytometry analysis with anti-ERBB2 antibody (1:1000, ab31889, Abcam) showed a significantly elevated HER-2-positive cells in trastuzumab-resistant cells compared to sensitive cells, *P

Additional file 3: Figure S1 Determination of IC50 values of breast cancer cells. (a-b) The IC50 values of breast cancer parental cells (SKBR-3 and BT474) and established trastuzumab-resistant cells (SKBR-3-TR and BT474-TR) were determined via CCK8 assay. (c-d) The IC50 values of trastuzumab-resistant cells transfected with si-NC or si-AFAP1-AS1 were determined accordingly.

Background Breast cancer angiogenesis is key for metastasis and predicts a poor prognosis. Angiotensin-converting enzyme 2 (ACE2), as a member of the renin-angiotensin system (RAS), was reported to restrain the progression of hepatocellular carcinoma (HCC) and non-small cell lung cancer (NSCLC) through inhibiting angiogenesis. However, the relationship between ACE2 and breast cancer angiogenesis remains unclear. Methods The prognosis and relative gene selection were analysed using the GEPIA, GEO, TCGA and STRING databases. ACE2 expression in breast cancer tissue was estimated by reverse transcription-quantitative polymerase chain reaction (qPCR). Breast cancer cell migration, proliferation and angiogenesis were assessed by Transwell migration, proliferation, tube formation, and wound healing assays. The expression of vascular endothelial growth factor A (VEGFa) was detected by qPCR and Western blotting. The phosphorylation of vascular endothelial growth factor receptor 2 (VEGFR2), mitogen-activated protein kinase 1/2 (MEK1/2), and extracellular signal-regulated protein kinase 1/2 (ERK1/2) was examined by Western blotting. Breast cancer metastasis and angiogenesis in vivo were measured using a zebrafish model. Results ACE2 was downregulated in breast cancer patients. Patients with higher ACE2 expression had longer relapse-free survival (RFS). In vitro, ACE2 inhibited breast cancer migration. Meanwhile, ACE2 in breast cancer cells inhibited human umbilical vascular endothelial cell (HUVEC) proliferation, tube formation and migration. In the zebrafish model, ACE2 inhibited breast cancer cell metastasis, as demonstrated by analyses of the number of disseminated foci and the metastatic distance. Neo-angiogenesis was also decreased by ACE2. ACE2 downregulated the expression of VEGFa in breast cancer cells. Furthermore, ACE2 in breast cancer cells inactivated the phosphorylation of VEGFR2, MEK1/2, and ERK1/2 in HUVECs. Conclusions Our findings suggest that ACE2, as a potential resister to breast cancer, might inhibit breast cancer angiogenesis through the VEGFa/VEGFR2/ERK pathway. Trial registration Retrospectively registered. Electronic supplementary material The online version of this article (10.1186/s13046-019-1156-5) contains supplementary material, which is available to authorized users.

Purpose The prognostic value of tumor-infiltrating Foxp3+ regulatory T cells (Tregs) in breast cancer remains controversial. Therefore, we performed this meta-analysis to determine the impact of Foxp3+ Tregs infiltration on survival outcomes. Methods Relevant literature was retrieved from Pubmed, Web of science and Cocohrane until May 30, 2016. Meta-analysis was performed using hazard ratios (HRs), odds ratio (OR) and 95 % confidence intervals (CI) as effect measures. Results Fourteen studies (10,259 patients) were included. Meta-analysis showed that high Foxp3+ Tregs infiltration was correlated with high histological grade (OR= 2.96, 95%CI [2.03-4.31]), estrogen receptor (ER) negativity (OR= 0.38, 95%CI [0.23-0.60]), human epidermal growth factor receptor type 2 (HER2) positivity (OR=2.43, 95%CI [1.69-3.51]). The detection of FOXP3+ Tregs was significantly associated with recurrence-free survival (RFS) of patients (HR = 1.58, 95 % CI [1.03-2.44]). Conclusion Our meta-analysis suggests that high Foxp3+ Tregs infiltration is associated with poor RFS in breast cancer patients and predicts histological grade, estrogen receptor and HER-2 status.

Improvements in stent-graft devices and increasing clinical experience with the technique have improved outcomes and expanded clinical indications in patients with Stanford type B aortic dissection (AD) in China. However, the evolution of and modifications to stent grafts have not been reviewed. The aim of this study was to summarize all available published data on technical success, potential benefits, complications, stent evolution, and survival rates associated with endovascular stent-graft placements in patients with Stanford type B AD in China.We performed comprehensive searches of the Chinese-language medical literature in Chinese Biomedical Database, China National Knowledge Infrastructure, and Wanfang Data and of the English-language medical literature in PubMed, Web of Science, and the Cochrane Library. This systematic review was based on all retrospective studies assessing outcomes of Stanford type B AD treated with endovascular stent-graft placement in China.A total of 153 retrospective studies that included 8,694 cases were analyzed in this study. Procedure success was reported in 99.7 ± 0.1% of patients. Overall complications were reported in 19.1 ± 0.6% of patients. Postoperative endoleaks occurred in 7.2 ± 0.3% of patients. Major complications were reported in 3.2 ± 0.2% of patients, with a neurological complication rate of 1.3 ± 0.1%. Periprocedural stroke occurred more frequently than did paraplegia (0.8 ± 0.1% vs. 0.1 ± 0.04%). Overall complications were significantly greater in patients treated with first-generation stents than in those treated with second-generation stents (25.1 ± 1.2% vs. 9.5 ± 0.9%, P 0.001). The in-hospital mortality rate was 1.6 ± 0.1%. In addition, 1.8 ± 0.2% of patients died during a mean follow-up period of 29.4 ± 13.5 months. The Kaplan-Meier estimates of the overall survival rate were 99.0 ± 0.1% at 30 days, 98.5 ± 0.2% at 6 months, 98.4 ± 0.2% at 1 year, 98.1 ± 0.2% at 2 years, and 97.9 ± 0.2% at 5 years.Endovascular stent-graft placement is feasible and has a high technique success rate as well as favorable neurological complication and survival rates when used to treat Stanford type B AD. The new generation of stent grafts appears to have favorable in-hospital and follow-up outcomes.

Table S3. Hub gene selection. (DOCX 19 kb)

Table S2. TCGA breast cancer clinical data stratified by the ACE2 expression level. (DOCX 20 kb)

Table S1. Clinical and pathological characteristics of breast cancer patients. (DOCX 17 kb)

Table S4. KEGG pathways between ACE2 and VEGFa. (DOCX 32 kb)

Supporting methods. (DOCX 19 kb)

To study the incidence of implantation metastasis of breast cancer in vacuum-assisted breast biopsy (VABB) needle tract in Chinese patients and evaluate the effect of neoadjuvant chemotherapy on needle tract metastasis following VABB.The breast cancer patients with established diagnosis by VABB were divided into two groups to receive open surgery or neoadjuvant chemotherapy prior to open surgery. The incidence of needle tract metastasis, disease-free survival (DFS) and overall survival (OS) were compared between the two groups.A total of 214 patients were enrolled, among whom 94 directly underwent surgeries and 120 had neoadjuvant chemotherapy before surgery. The two groups showed no significant differences in the incidence of needle tract metastasis (3.2% vs 0.8%, P=0.206), DFS (P=0.221), or OS (P=0.531).The incidence of needle tract metastasis is low after VABB, and neoadjuvant chemotherapy does not increase this risk.