Lnc NR2F1-AS1 Promotes Breast Cancer Metastasis by Targeting the MiR-25-3p/ZEB2 Axis.

Background: Long noncoding RNAs (lncRNAs) substantially affect tumor metastasis and are aberrantly expressed in various cancers. However, its role in breast cancer (BC) remains unclear. Methods: A microarray assay of differentially expressed lncRNAs in epithelial-mesenchymal transition (EMT) and non-EMT cells was performed. The prognostic value of lnc NR2F1-AS1 expression in patients with BC was analyzed using The Cancer Genome Atlas database. Lnc NR2F1-AS1 expression levels in different BC cell lines were assessed using quantitative real-time PCR. The role of lnc NR2F1-AS1 in BC cell metastasis was investigated in vitro and in vivo. Dual luciferase reporter assay and RNA immunoprecipitation were performed to investigate the relationship between lnc NR2F1-AS1, miR-25-3p, and ZEB2. Results: High levels of lnc NR2F1-AS1 were observed in BC cells undergoing EMT and were closely correlated with adverse prognosis in patients with BC. Lnc NR2F1-AS1 knockdown significantly inhibited BC cell migration, invasiveness in vitro, and metastasis in vivo. Mechanistically, lnc NR2F1-AS1 competitively binds to miR-25-3p to impede ZEB2 degradation, a positive EMT transcription factor in BC. Conclusions: Our study revealed a novel lnc NR2F1-AS1/miR-25-3p/ZEB2 axis in BC metastasis and that lnc NR2F1-AS1 may serve as a potential therapeutic target for BC metastasis.

lncRNA NR2F1-AS1 promotes breast cancer angiogenesis through activating IGF-1/IGF-1R/ERK pathway.

Long non-coding RNAs (lncRNAs) take various effects in cancer mostly through sponging with microRNAs (miRNAs). lncRNA NR2F1-AS1 is found to promote tumour progression in hepatocellular carcinoma, endometrial cancer and thyroid cancer. However, the role of lncRNA NR2F1-AS1 in breast cancer angiogenesis remains unknown. In this study, we found lncRNA NR2F1-AS1 was positively related with CD31 and CD34 in breast cancer through Pearson's correlation analysis, while lncRNA NR2F1-AS1 transfection promoted human umbilical vascular endothelial cell (HUVEC) tube formation. In breast cancer cells, lncRNA NR2F1-AS1 enhanced the HUVEC proliferation, tube formation and migration ability through tumour-conditioned medium (TCM). In zebrafish model, lncRNA NR2F1-AS1 increased the breast cancer cell-related neo-vasculature and subsequently promoted the breast cancer cell metastasis. In mouse model, lncRNA NR2F1-AS1 promoted the tumour vessel formation, increased the micro vessel density (MVD) and then induced the growth of primary tumour. Mechanically, lncRNA NR2F1-AS1 increased insulin-like growth factor-1 (IGF-1) expression through sponging miRNA-338-3p in breast cancer cells and then activated the receptor of IGF-1 (IGF-1R) and extracellular signal-regulated kinase (ERK) pathway in HUVECs. These results indicated that lncRNA NR2F1-AS1 could promote breast cancer angiogenesis through IGF-1/IGF-1R/ERK pathway.

KCTD12 promotes G1/S transition of breast cancer cell through activating the AKT/FOXO1 signaling.

BACKGROUND: Sustaining proliferation is the most fundamental step for breast cancer tumor genesis. Accelerated proliferation is usually linked to the uncontrolled cell cycle. However, the internal and external factors linked to the activation of breast cancer cell cycle are still to be investigated. METHODS: quantitative PCR (qPCR) and Western blotting assay were used to detect the expression of potassium channel tetramerization domain containing 12 (KCTD12) in breast cancer. MTT and colony formation assays were performed to evaluate the effect of KCTD12 on cell proliferation of breast cancer. Anchorage-independent growth assay was used to examine the in vitro tumorigenesis of breast cancer cells. Flow cytometry assay, qPCR, and Western blotting were used to investigate the detailed mechanisms of KCTD12 on breast cancer progression. RESULTS: Herein, the result showed that the level of KCTD12 is significantly decreased in breast cancer tissues and cells, and lower level of KCTD12 predicts poorer survival for patients with breast cancer. Further cell function tests illustrated that downregulation of KCTD12 significantly promotes cell proliferation and in vitro tumor genesis. Besides, molecular biologic experiments showed that downregulation of KCTD12 can enhance the G1/S transition through activating the AKT/FOXO1 signaling. CONCLUSION: Our study inferred that downregulation of KCTD12 can be a novel factor for poor prognosis in breast cancer.

MicroRNA-200a confers chemoresistance by antagonizing TP53INP1 and YAP1 in human breast cancer.

BACKGROUND: Emerging evidence suggests molecular and phenotypic association between treatment resistance and epithelial-mesenchymal transition (EMT) in cancer. Compared with the well-defined molecular events of miR-200a in EMT, the role of miR-200a in therapy resistance remains to be elucidated. METHODS: Breast cancer cells transfected with mimic or inhibitor for miR-200a was assayed for chemoresistance in vitro. miR-200a expression was assessed by quantitative real-time PCR (qRT-PCR) in breast cancer patients treated with preoperative chemotherapy. Luciferase assays, cell proliferation assay were performed to identify the targets of miR-200a and the mechanism by which it promotes treatment resistance. Survival analysis was used to evaluate the prognosis value of miR-200a. RESULTS: In this study, our results showed ectopic expression of miR-200a promotes chemoresistance in breast cancer cell lines to several chemotherapeutic agents, whereas inhibition of miR-200a enhances gemcitabine chemosensitivity in resistance cancer cells. We found overexpression of miR-200a was closely associated with poor response to preoperative chemotherapy and poor prognosis in breast cancer patients. Furthermore, knockdown of YAP1 and TP53INP1 phenocopied the effects of miR-200a overexpression, and confirmed that TP53INP1 is a novel target of miR-200a. Remarkably, TP53INP1 expression is inversely correlated with miR-200a expression in Breast cancer cell lines. Taken together, these clinical and experimental results demonstrate that miR-200a is a determinant of chemoresistance of breast cancer. CONCLUSIONS: Upregulated miR-200a enhances treatment resistance via antagonizing TP53INP1 and YAP1 in breast cancer.

Bioprinted, spatially defined breast tumor microenvironment models of intratumoral heterogeneity and drug resistance.

Cellular, extracellular matrix (ECM), and spatial heterogeneity of tumor microenvironments (TMEs) regulate disease progression and treatment efficacy. Developing in vitro models that recapitulate the TME promises to accelerate studies of tumor biology and identify new targets for therapy. Here, we used extrusion-based, multi-nozzle 3D bioprinting to spatially pattern triple-negative MDA-MB-231 breast cancer cells, endothelial cells (ECs), and human mammary cancer-associated fibroblasts (HMCAFs) with biomimetic ECM inks. Bioprinted models captured key features of the spatial architecture of human breast tumors, including varying-sized dense regions of cancer cells and surrounding microvessel-rich stroma. Angiogenesis and ECM stiffening occurred in the stromal area but not the cancer cell-rich (CCR) regions, mimicking pathological changes in patient samples. Transcriptomic analyses revealed upregulation of angiogenesis-related and ECM remodeling-related signatures in the stroma region and identified potential ligand-receptor (LR) mediators of these processes. Breast cancer cells in distinct parts of the bioprinted TME showed differing sensitivities to chemotherapy, highlighting environmentally mediated drug resistance. In summary, our 3D-bioprinted tumor model will act as a platform to discover integrated functions of the TME in cancer biology and therapy.

Comparison of clinicopathological characteristics and response to neoadjuvant chemotherapy between HER2-low and HER2-zero breast cancer.

Novel anti-HER2 antibody-drug conjugates trastuzumab deruxtecan (DS-8201a) showed its effect in previously-treated HER2-low metastatic breast cancer, suggesting a promising future in HER2-low breast cancer. We retrospectively reviewed the clinicopathological data of 325 patients with stage I-III HER2 negative breast cancer who received neoadjuvant chemotherapy in the First Affiliated Hospital of Sun Yat-sen University from January 2016 to June 2021. In general, 91 patients (28.0%) were HER2-zero, and 234 patients (72.0%) were HER2-low. The pathological complete response (pCR) rate of the entire cohort was 17.3%. The pCR rate was 16.7% in HER2-low group, and 18.9% in HER2-zero group, showing no significant difference. Patients with HER2-low tumors had significantly longer overall survival (OS) than patients with HER2-zero tumors. ER status was the affecting factor of OS in HER2-low patients in both univariate and multivariate analysis. In conclusion, evidence for HER2-low BC as a distinct entity is insufficient, and more efforts are needed to standardize the scoring of HER2-low breast cancer.

Dissecting the role of cancer-associated fibroblast-derived biglycan as a potential therapeutic target in immunotherapy resistance: A tumor bulk and single-cell transcriptomic study.

INTRODUCTION: Cancer-associated fibroblasts (CAFs) are correlated with the immunotherapy response. However, the culprits that link CAFs to immunotherapy resistance are still rarely investigated in real-world studies. OBJECTIVES: This study aims to systematically assess the landscape of fibroblasts in cancer patients by combining single-cell and bulk profiling data from pan-cancer cohorts. We further sought to decipher the expression, survival predictive value and association with immunotherapy response of biglycan (BGN), a proteoglycan in the extracellular matrix, in multiple cohorts. METHODS: Pan-cancer tumor bulks and 27 single-cell RNA sequencing cohorts were enrolled to investigate the correlations and crosstalk between CAFs and tumor or immune cells. Specific secreting factors of CAFs were then identified by expression profiling at tissue microdissection, isolated primary fibroblasts and single-cell level. The role of BGN was further dissected in additional three bulk and five single-cell profiling datasets from immunotherapy cohorts and validated in real-world patients who have received PD-1 blockade using immunohistochemistry and immunofluorescence. RESULTS: CAFs were closely correlated with immune components. Frequent crosstalk between CAFs and other cells was revealed by the CellChat analysis. Single-cell regulatory network inference and clustering identified common and distinct regulators for CAFs across cancers. The BGN was determined to be a specific secreting factor of CAFs. The BGN served as an unfavourable indicator for overall survival and immunotherapy response. In the real-world immunotherapy cohort, patients with high BGN levels presented a higher proportion of poor response compared with those with low BGN (46.7% vs. 11.8%) and a lower level of infiltrating CD8+ T cells was also observed. CONCLUSIONS: We highlighted the importance of CAFs in the tumor microenvironment and revealed that the BGN, which is mainly derived from CAFs, may be applicable in clinical practice and serve as a therapeutic target in immunotherapy resistance.

BRCA1 Insufficiency Induces a Hypersialylated Acidic Tumor Microenvironment That Promotes Metastasis and Immunotherapy Resistance.

Cancer metastasis is an extremely complex process affected by many factors. An acidic microenvironment can drive cancer cell migration toward blood vessels while also hampering immune cell activity. Here, we identified a mechanism mediated by sialyltransferases that induces an acidic tumor-permissive microenvironment (ATPME) in BRCA1-mutant and most BRCA1-low breast cancers. Hypersialylation mediated by ST8SIA4 perturbed the mammary epithelial bilayer structure and generated an ATPME and immunosuppressive microenvironment with increased PD-L1 and PD1 expressions. Mechanistically, BRCA1 deficiency increased expression of VEGFA and IL6 to activate TGFß-ST8SIA4 signaling. High levels of ST8SIA4 led to accumulation of polysialic acid (PSA) on mammary epithelial membranes that facilitated escape of cancer cells from immunosurveillance, promoting metastasis and resistance to αPD1 treatment. The sialyltransferase inhibitor 3Fax-Peracetyl Neu5Ac neutralized the ATPME, sensitized cancers to immune checkpoint blockade by activating CD8 T cells, and inhibited tumor growth and metastasis. Together, these findings identify a potential therapeutic option for cancers with a high level of PSA. SIGNIFICANCE: BRCA1 deficiency generates an acidic microenvironment to promote cancer metastasis and immunotherapy resistance that can be reversed using a sialyltransferase inhibitor.

The prognostic role of a phospho-Stathmin 1 signature in breast cancer treated with neoadjuvant chemotherapy.

Background: High expression of Stathmin 1 (STMN1) protein is related to a poor prognosis in various tumors, including breast cancer. In our previous study, a phospho-STMN1 signature was conducted to predict outcomes in adjuvantly treated breast cancer patients. This study aimed to explore the relationship of STMN1 expression with our phospho-STMN1 signature and the prognosis of patients treated with neoadjuvant chemotherapy (NACT). Methods: A retrospective analysis of 116 patients who received NACT in The First Affiliated Hospital of Sun Yat-sen University between December 2008 and March 2016 was conducted. Patients were followed up through telephone once a year until 2022. The levels of STMN1, Ser16, Ser25, Ser38, and Ser63 phosphorylation and GRP78 expression in pre-NACT biopsy specimens from the patients were detected by immunohistochemistry. The recurrence risk score for each patient was calculated using the p-STMN1/GRP78 model. Clinical and pathological parameters, pathological complete response and objective response rates, and survival data were analyzed. Results: In patients with NACT-treated breast cancer, high levels of STMN1, Ser25 phosphorylation, Ser38 phosphorylation, and GRP78 were related to worse disease-free survival (DFS), as was a high p-STMN1/GRP78 model risk score. In contrast, high Ser16 and Ser63 phosphorylation levels were related to better DFS [p-STMN1/GRP78 model: P=0.002, HR =0.180 (0.061-0.534); STMN1: P=0.001, HR =0.290 (0.147-0.572); Ser16: P=0.036, HR =2.019 (1.049-3.886); Ser25: P=0.013, HR =0.392 (0.188-0.819); Ser38: P=0.001, HR =0.293 (0.153-0.559); Ser63: P=0.006, HR =3.346 (1.407-7.961); GRP78: P=0.010, HR =0.417 (0.214-0.815)]. However, no significant statistical difference was found in the multivariate regression. The relationship between these markers and the therapeutic effect of NACT (pathological complete response and objective response) showed the same tendency with survival. The area under the receiver operating characteristic curve for the p-STMN1/GRP78 model was 0.790 (P=0.001) with sensitivity of 70% and specificity of 74%. Conclusions: The expression and serine phosphorylation status of STMN1 may be beneficial as biomarkers for predicting the prognosis of breast cancer patients treated with NACT. Our p-STMN1/GRP78 model could become a widely applied signature for assessing the metastatic risk of breast cancer patients, potentially facilitating their individualized management before NACT.

LINC01194 recruits NUMA1 to promote ubiquitination of RYR2 to enhance malignant progression in triple-negative breast cancer.

Long intergenic nonprotein coding RNA 1194 (LINC01194) has been reported as an oncogene in several cancer types, but its expression and potential role in triple-negative breast cancer (TNBC) are still unclear. We found that LINC01194 was significantly highly expressed in TNBC based on The Cancer Genome Atlas (TCGA) database. Data from in vitro experiments and in vivo assays demonstrated that LINC01194 promoted TNBC progression. Through bioinformatics prediction, mass spectrometry, and mechanical experiments, we found that LINC01194 could recruit nuclear mitotic apparatus protein 1 (NUMA1) to bind to the untranslated region (3'UTR) of ubiquitin-conjugating enzyme E2 C (UBE2C) 3' and stabilize UBE2C mRNA. Moreover, we found that UBE2C acted as an ubiquitin ligase to promote the ubiquitination and degradation of ryanodine receptor type 2 (RYR2) that inhibited the progression of TNBC by inhibiting the Wnt/ß-catenin signaling pathway. In summary, LINC01194 activate the Wnt/ß-catenin signaling pathway and accelerates the malignant progression of TNBC by recruiting NUMA1 to stabilize UBE2C mRNA and thus promotes RYR2 ubiquitination and degradation. These findings might provide a more effective therapeutic strategy for TNBC patients.

KIF17 maintains the epithelial phenotype of breast cancer cells and curbs tumour metastasis.

Kinesin superfamily motor protein 17 (KIF17) was previously identified downregulated in breast cancer and correlated with patient prognosis. However, its pathophysiological role in tumours remains unknown. Here, we confirmed that KIF17 was significantly under-expressed in breast cancer tissues and low KIF17 expression correlated with poor outcomes in patients with breast cancer. In vitro and in vivo experiments demonstrated that KIF17 overexpression in breast cancer cell lines significantly inhibited breast cancer invasion and metastasis. By establishing the lung metastatic MDA-MB-231 cell lines, we found a transient silence of KIF17 during the initiation of breast cancer metastasis. Further experiments revealed that KIF17 might suppress metastasis by regulating the level of acetylated tubulin to maintain cytoskeleton stability. Eventually, we found that the low expression of KIF17 in breast cancer is regulated by DNMT1-mediated 5-mC DNA methylation and epigenetic silencing. Decitabine can effectively improve the expression level of KIF17 in breast cancer cells. Our study demonstrates that KIF17 mediates microtubule acetylation to maintain the stability of microtubules, thereby inhibiting tumour invasion and metastasis.

Quantification of ferroptosis pathway status revealed heterogeneity in breast cancer patients with distinct immune microenvironment.

Clinical significance and biological functions of the ferroptosis pathway were addressed in all aspect of cancer regarding multi-omics level; however, the overall status of ferroptosis pathway alteration was hard to evaluate. The aim of this study is to comprehensively analyze the putative biological, pathological, and clinical functions of the ferroptosis pathway in breast cancer on a pathway level. By adopting the bioinformatic algorithm "pathifier", we quantified five programmed cell death (PCD) pathways (KO04210 Apoptosis; KO04216 Ferroptosis; KO04217 Necroptosis; GO:0070269 Pyroptosis; GO:0048102 Autophagic cell death) in breast cancer patients, and we featured the clinical characteristics and prognostic value of each pathway in breast cancer and found significantly activated PCD in cancer patients, among which ferroptosis demonstrated a significant correlation with the prognosis of breast cancer. Correlation analysis between PCD pathways identified intra-tumor heterogeneity of breast cancer. Therefore, clustering of patients based on the status of PCD pathways was done. Comparisons between subgroups highlighted specifically activated ferroptosis in cluster 2 patients, which showed the distinct status of tumor immunity and microenvironment from other clusters, indicating putative correlations with ferroptosis. NDUFA13 was identified and selected as a putative biomarker for cluster 2 patients. Experimental validations were executed on cellular level and NDUFA13 showed an important role in regulating ferroptosis activation and can work as a biomarker for ferroptosis pathway status. In conclusion, the status of the ferroptosis pathway significantly correlated with the clinical outcomes and intra-tumor heterogeneity of breast cancer, and NDUFA13 expression was identified as a positive biomarker for ferroptosis pathway activation in breast cancer patients.

Sequential versus concurrent adjuvant chemo-endocrine therapy for HR+ early breast cancer: a systematic review and Bayesian network meta-analysis.

Background: Chemo-endocrine therapy is the standard adjuvant treatment strategy for hormone receptor-positive (HR+) early breast cancer. Our research aimed to compare the efficacy of adjuvant chemo-endocrine therapies, regarding different endocrinal regimens and integration sequences (sequential or concomitant), for HR+ early breast cancer. Methods: PubMed, Embase, the Cochrane Library and web of science were searched for articles published before October 2018 with Clinicaltrials.gov (https://clinicaltrials.gov) for registered clinical trials and ASCO, AACR, ESCO, SABCS meeting abstracts for addition. Randomized clinical trials (RCTs) comparing chemotherapy and/or endocrine therapy in the adjuvant treatment of primary breast cancer patients were included. Hazard ratios (HRs) of disease-free survival (DFS) and overall survival (OS) were extracted and analyzed in Bayesian analysis. Patients were stratified by menopause status. Results: Thirty-three trials with 28,515 patients and 19 treatments were enrolled. Comparisons between regimens has seen better efficacy of ovarian function suppressor (OFS) + aromatase inhibitors (AI) than OFS + tamoxifen, either used concurrently [HR =0.69, 95% credible intervals (CrI): 0.47-1.02] or sequentially with chemotherapy (HR =0.72, 95% CrI: 0.49-1.06) in premenopausal patients. Adding OFS to tamoxifen was marginally better than tamoxifen used alone (DFS: HR =0.85, 95% CrI: 0.65-1.09; OS: HR =0.77, 95% CrI: 0.52-1.08). Comparisons between different sequences of chemo-endocrine therapy proved equal efficacy in premenopausal and postmenopausal patients. Recommendation was given based on ranking of treatments. Sequential and concurrent use of chemotherapy and OFS + AI ranked equally in premenopausal patients and were recommended as the best option. However, tamoxifen ranked higher when used concurrently with chemotherapy in both premenopausal and postmenopausal HR+ early breast cancer. Conclusions: In the adjuvant chemo-endocrine therapy for premenopausal HR+ early breast cancer, concurrent and sequential adjuvant chemo-endocrine therapy was demonstrated of equal efficacy in both postmenopausal and premenopausal HR+ early breast cancer. Trial Registration: PROSPERO CRD42018104889.

LncRNA LGALS8-AS1 Promotes Breast Cancer Metastasis Through miR-125b-5p/SOX12 Feedback Regulatory Network.

BACKGROUND: Metastasis is a major factor weakening the long-term survival of breast cancer patients. Increasing evidence revealed that long non-coding RNAs (lncRNAs) were involved in the occurrence and development of breast cancer. In this study, we aimed to investigate the role of LGALS8-AS1 in the metastatic progression of breast cancer cells and its potential mechanisms. RESULTS: The lncRNA LGALS8-AS1 was highly expressed in breast cancer and associated with poor survival. LGALS8-AS1 functioned as an oncogenic lncRNA that promoted the metastasis of breast cancer both in vitro and in vivo. It upregulated SOX12 via competing as a competing endogenous RNA (ceRNA) for sponging miR-125b-5p and acted on the PI3K/AKT signaling pathway to promote the metastasis of breast cancer. Furthermore, SOX12, in turn, activated LGALS8-AS1 expression via direct recognition of its sequence binding enrichment motif on the LGALS8-AS1 promoter, thereby forming a positive feedback regulatory loop. CONCLUSION: This study manifested a novel mechanism of LGALS8-AS1 facilitating the metastasis of breast cancer. The LGALS8-AS1/miR-125b-5p/SOX12 reciprocal regulatory loop dyscrasia promoted the migration and invasion of breast cancer cells. This signaling axis could be applicable to the design of novel therapeutic strategies against this malignancy.

Tripartite motif-containing 3 (TRIM3) enhances ER signaling and confers tamoxifen resistance in breast cancer.

Tamoxifen resistance remains a clinical problem in estrogen receptor (ER)-positive breast cancer. SUMOylation of ERα enhances ERα-induced transcription activity. Tripartite motif-containing (TRIM) proteins are a new class of SUMO E3 ligases, which regulate the SUMOylation of proteins. However, the precise molecular mechanism and function of TRIM3 in SUMOylation and the response to tamoxifen remain unclear. In the present study, we observed that TRIM3 was dramatically overexpressed in breast cancer, which correlated with tamoxifen resistance. Furthermore, TRIM3 overexpression significantly correlated with poor survival of patients with ER+ breast cancer treated with tamoxifen. TRIM3 overexpression conferred cell survival and tumorigenesis, whereas knocking down of TRIM3 reduced these capabilities. Moreover, TRIM3, as a ubiquitin carrier protein 9 (UBC9) binding protein, promoted SUMO modification of estrogen receptor 1 (ESR1) and activated the ER pathway. Silencing UBC9 abolished the function of TRIM3 in regulating tamoxifen resistance. These results suggest TRIM3 as a novel biomarker for breast cancer therapy, indicating that inhibiting TRIM3 combined with tamoxifen might provide a potential treatment for breast cancer.

ZNF367-induced transcriptional activation of KIF15 accelerates the progression of breast cancer.

Breast cancer (BC) is one of the most common female cancers, and its incidence has been increasing in recent years. Although treatments are continuously improving, the prognosis of patients in the advanced stage is still unsatisfactory. Thus, an in-depth understanding of its molecular mechanisms is necessary for curing breast cancer. KIF15 is a tetrameric spindle motor which can regulate mitosis in cellular process and exert the crucial functions in several cancers. The purpose of our research was to investigate the functions of KIF15 in breast cancer. We tested the expression of KIF15 in breast cancer tissues and the survival rate of breast cancer patients with high or low level of KIF15 through TCGA data. What's more, western blot and immunohistochemistry assay were utilized to evaluate the protein level and mRNA level of KIF15 in breast cancer tissues. Then CCK-8, wound healing, transwell and flow cytometry experiments were adopted separately to test cell viability, migration, invasion and cell cycle distribution. We discovered that KIF15 was highly expressed in breast cancer tissues and high level KIF15 was associated with a low survival rate of breast cancer patients. Moreover, silence of KIF15 suppressed cell viability, migration, invasion and cell cycle distribution. Following, we discovered that ZNF367 was the upstream transcription factor of KIF15. In addition, silenced ZNF367 could also repress the growth of breast cancer cells. And rescue experiments indicated that overexpressed KIF15 could counteract the inhibition effect of silencing ZNF367 on the progression of breast cancer. Importantly, we discovered that KIF15 and ZNF367 were associated with the regulation of cell cycle. In short, ZNF367-activated KIF15 accelerated the progression of breast cancer by regulating cell cycle progress.

Downregulation of transgelin 2 promotes breast cancer metastasis by activating the reactive oxygen species/nuclear factor­κB signaling pathway.

Transgelin 2 (TAGLN2) is a cytoskeletal protein of the calponin family. Abnormal expression of TAGLN2 was observed in various types of cancer. Our previous study reported that TAGLN2 expression was reduced in lymph node­positive breast cancer patients; however, the role of TAGLN2 in breast cancer metastasis remains unknown. In the present study, the role of TAGLN2 in breast cancer metastasis was investigated in vitro and in vivo via Transwell migration, luciferase and flow cytometry assays, and a mouse xenograft model. Proteins interacting with TAGLN2 were identified via co­immunoprecipitation assays and liquid chromatography/mass spectrometry, and the signaling pathway associated with the effects of TAGLN2 was investigated. Additionally, western blotting and reverse transcription­quantitative polymerase chain reaction were performed to further explore the potential pathway in which TAGLN2 may be involved and the mechanism underlying its effects in breast cancer metastasis. The present study reported that TAGLN2 expression was increased by 11.4­fold in patients without distant metastasis compared with those positive for distant metastasis. Knockdown of TAGLN2 resulted in increased cell migration in vitro and promoted lung metastasis in vivo. Additionally, overexpression of TAGLN2 suppressed lung metastasis in a mouse model. Peroxiredoxin 1 (PRDX1), an important reactive oxygen species (ROS) regulator, was revealed to interact with TAGLN2. In addition, mitochondrial redistribution and PRDX1 downregulation were reported following TAGLN2 silencing, which promoted ROS production and nuclear factor (NF)­κB activation in breast cancer cells. This induced the expression of metastasis­associated genes, including C­X­C chemokine receptor 4, matrix metalloproteinase (MMP)1 and MMP2. The present study proposed TAGLN2 to function as a tumor suppressor and that loss of TAGLN2 may promote the metastasis of breast cancer by activating the ROS/NF­κB signaling pathway.

Characterization of PIK3CA and PIK3R1 somatic mutations in Chinese breast cancer patients.

Deregulation of the phosphoinositide 3-kinase (PI3K) pathway contributes to the development and progression of tumors. Here, we determine that somatic mutations in PIK3CA (44%), PIK3R1 (17%), AKT3 (15%), and PTEN (12%) are prevalent and diverse in Chinese breast cancer patients, with 60 novel mutations identified. A high proportion of tumors harbors multiple mutations, especially PIK3CA plus PIK3R1 mutations (9.0%). Next, we develop a recombination-based mutation barcoding (ReMB) library for impactful mutations conferring clonal advantage in proliferation and drug responses. The highest-ranking PIK3CA and PIK3R1 mutations include previously reported deleterious mutations, as well as mutations with unknown significance. These PIK3CA and PIK3R1 impactful mutations exhibit a mutually exclusive pattern, leading to oncogenesis and hyperactivity of PI3K pathway. The PIK3CA impactful mutations are tightly associated with hormone receptor positivity. Collectively, these findings advance our understanding of PI3K impactful mutations in breast cancer and have important implications for PI3K-targeted therapy in precision oncology.

Androgen receptor expression predicts different clinical outcomes for breast cancer patients stratified by hormone receptor status.

In this study we sought to correlate androgen receptor (AR) expression with tumor progression and disease-free survival (DFS) in breast cancer patients. We investigated AR expression in 450 breast cancer patients. We found that breast cancers expressing the estrogen receptor (ER) are more likely to co-express AR compared to ER-negative cancers (56.0% versus 28.1%, P < 0.001). In addition, we found that AR expression is correlated with increased DFS in patients with luminal breast cancer (P < 0.001), and decreased DFS in TNBC (triple negative breast cancer, P = 0.014). In addition, patients with HR+ tumors (Hormone receptor positive tumors) expressing low levels of AR have the lowest DFS among all receptor combinations. We also propose a novel prognostic model using AR receptor status, BRCA1, and present data showing that our model is more predictive of disease free survival compared to the traditional TMN staging system.

The phosphorylation-specific association of STMN1 with GRP78 promotes breast cancer metastasis.

Metastasis is a major cause of death in patients with breast cancer. Stathmin1 (STMN1) is a phosphoprotein associated with cancer metastasis. It exhibits a complicated phosphorylation pattern in response to various extracellular signals, but its signaling mechanism is poorly understood. In this study, we report that phosphorylation of STMN1 at Ser25 and Ser38 is necessary to maintain cell migration capabilities and is associated with shorter disease-free survival (DFS) in breast cancer. In addition, we report that glucose-regulated protein of molecular mass 78 (GRP78) is a novel phospho-STMN1 binding protein upon STMN1 Ser25/Ser38 phosphorylation. This phosphorylation-dependent interaction is regulated by MEK kinase and is required for STMN1-GRP78 complex stability and STMN1-mediated migration. We also propose a prognostic model based on phospho-STMN1 and GRP78 to assess metastatic risk in breast cancer patients.