The Role of CD8A in the Immune Microenvironment of Breast Cancer.

BACKGROUND: Triple-negative breast cancer (TNBC) is an aggressive form of breast cancer (BC), and it is often associated with a high tumor grade, a younger age at diagnosis, and a low survival rate. Conventional endocrine and anti-HER-2 therapies are usually ineffective against TNBC, creating treatment challenges and resulting in a poor prognosis. Hence, new targets and treatment strategies for TNBC are urgently required. METHODS: The GSE102818 dataset was used to identify differentially expressed genes (DEGs) between primary BC and metastatic BC lesions. The Cancer Genome Atlas and the cBioPortal platform were employed to explore mutations in candidate genes. Utilizing the Tumor IMmune Estimation Resource (TIMER), the relationship between the expression of candidate genes and immune cell infiltration was assessed. Additionally, the cell-specific expression of the candidate genes was examined in the immune microenvironment of primary BC and metastatic BC lesions using the single-cell RNA sequencing (scRNA-seq) datasets GSE118389 and GSE202695. Finally, the protein expression of the candidate genes in clinical TNBC samples was evaluated. RESULTS: CD8A was identified as a hub gene in the DEG network and was found to be down-regulated in metastatic BC lesions. CD8A expression was highly correlated with the infiltration of CD8+ T cells, and elevated CD8A expression was correlated with improved survival. Interestingly, scRNA-seq data revealed that CD8A was down-regulated in CD8+ T cells in the immune microenvironment of metastatic BC lesions. Finally, the evaluation of clinical samples confirmed the down-regulation of CD8A in the immune microenvironment of BC lung metastases. CONCLUSIONS: In patients with metastatic TNBC, high levels of CD8A (especially in the immune microenvironment) are associated with a good prognosis.

Zinc finger and SCAN domain containing 1, ZSCAN1, is a novel stemness-related tumor suppressor and transcriptional repressor in breast cancer targeting TAZ.

Introduction: Cancer stem cells (CSCs) targeted therapy holds the potential for improving cancer management; identification of stemness-related genes in CSCs is necessary for its development. Methods: The Cancer Genome Atlas (TCGA) and the Molecular Taxonomy of Breast Cancer International Consortium (METABRIC) datasets were used for survival analysis. ZSCAN1 correlated genes was identified by Spearman correlation analysis. Breast cancer stem-like cells (BCSLCs) were isolated by sorting CD44+CD24- cells from suspension cultured breast cancer (BC) spheroids. The sphere-forming capacity and sphere- and tumor-initiating capacities were determined by sphere formation and limiting dilution assays. The relative gene expression was determined by qRT-PCR, western blot. Lentivirus system was used for gene manipulation. Nuclear run-on assay was employed to examine the levels of nascent mRNAs. DNA pull-down and Chromatin immunoprecipitation (ChIP) assays were used for determining the interaction between protein and target DNA fragments. Luciferase reporter assay was used for evaluating the activity of the promoter. Results and discussion: ZSCAN1 is aberrantly suppressed in BC, and this suppression indicates a bad prognosis. Ectopic expression of ZSCAN1 inhibited the proliferation, clonogenicity, and tumorigenicity of BC cells. ZSCAN1-overexpressing BCSLCs exhibited weakened stemness properties. Normal human mammary epithelial (HMLE) cells with ZSCAN1 depletion exhibited enhanced stemness properties. Mechanistic studies showed that ZSCAN1 directly binds to -951 ~ -925bp region of WWTR1 (encodes TAZ) promoter, inhibits WWTR1 transcription, thereby inhibiting the stemness of BCSCs. Our work thus revealed ZSCAN1 as a novel stemness-related tumor suppressor and transcriptional repressor in BC.

Prediction of Clinical Molecular Typing of Breast Invasive Ductal Carcinoma Using 18F-FDG PET/CT Dual-Phase Imaging.

RATIONALE AND OBJECTIVES: To investigate the diagnostic value of Fluorine-18-labeled 2-fluoro-2-deoxy-D-glucose positron emission tomography and computed tomography (18F-FDG PET/CT) dual-phase imaging for the different molecular subtypes of invasive ductal carcinoma of the breast. MATERIALS AND METHODS: Clinical imaging data of 164 women with invasive ductal carcinoma of the breast confirmed by pathology who underwent 18F-FDG PET/CT dual-phase imaging were retrospectively analyzed. The maximum standard uptake values (SUVmax) of the early and delayed phases of the lesion were measured and recorded as SUVmax1 and SUVmax2, respectively, and the retention index (RI) was calculated. We analyzed the change rule of SUVmax1, SUVmax2, and RI for the different molecular subtypes and molecular marker expression groups. The diagnostic threshold of different molecular marker expression status was determined using receiver operating characteristic curve analysis. RESULTS: SUVmax1 and SUVmax2 were highest in the TNBC group and lowest in the luminal A group (p<0.001). TNBC and HER2 overexpression groups had higher RI than the luminal A and B groups (p<0.001), with no significant difference between the TNBC and HER2 overexpression groups or between the luminal A and B groups (p=0.640 and 0.345, respectively). The ER- and PR-negative groups had significantly higher SUVmax1, SUVmax2, and RI than the PR-positive group (p<0.001). The HER2-positive group had higher SUVmax1 and SUVmax2 than the negative group (p<0.001). The Ki67 overexpression group had higher SUVmax1 and SUVmax2 levels than the low expression group (p<0.001). There was no significant difference in RI between HER2-positive and negative groups or between Ki67 high and low expression groups (p=0.904 and 0.216, respectively). For ER-negative and positive expression status, the maximum area under the curve (AUC) of SUVmax2 was 0.852, diagnostic threshold was 10.87, sensitivity was 79.6%, and specificity was 74.5%. For PR-negative and positive expression status, the AUC of SUVmax2 was 0.858, diagnostic threshold was 10.45, sensitivity was 83.1%, and specificity was 75.3%. For HER2-negative and positive expression status, the AUC of SUVmax1 was 0.714, diagnostic threshold was 9.28, sensitivity was 79.6%, and specificity was 60.9%. For Ki67 high- and low expression status, the AUC of SUVmax2 was 0.915 at maximum, diagnostic threshold was 10.21, sensitivity was 83.4%, and specificity was 93.9%. CONCLUSION: 18F-FDG PET/CT dual-phase imaging facilitates the prediction of the expression of molecular markers and subtypes of invasive ductal carcinoma of the breast and the development of more tailored treatment plans for patients with this disease.

KLF14 alleviated breast cancer invasion and M2 macrophages polarization through modulating SOCS3/RhoA/Rock/STAT3 signaling.

PURPOSE: To study the functions and underlying network of KLF14 in breast cancer invasion and tumor-associated macrophages (TAMs). METHODS: The expressions of gene or protein were assessed by qRT-PCR and western blot assays, respectively. Cell proliferation and invasion were investigated by colony formation, CCK-8 and transwell assays, respectively. Macrophage M2 polarization was identified by flow cytometry assay. The methylation level was tested by methylation Specific PCR (MSP). The molecular relationship between KLF14 and SOCS3 was validated by dual luciferase and ChIP assays. In vivo model was established to confirm effect of KLF14 on tumor growth and metastasis. RESULTS: KLF14 was downregulated in breast cancer, and its level was modified by CpG-mediated methylation. Overexpression of KLF14 significantly inhibited the proliferation and invasion of breast cancer in vitro and in vivo. Moreover, KLF14-overexpressing breast cancer cells notably reduced M2 macrophages polarization and it related promoting factor of tumor microenvironment (EGF, TGFß, MMP9 and VEGF). Mechanistically, KLF14 could positively activate SOCS3 transcription, then blocking the activation of RhoA/Rock/STAT3 signaling. Further rescue experiments identified that either SOCS3 silencing and activation of RhoA/Rock/STAT3 signaling dramatically restrained the regulatory roles of KLF14 overexpression in breast cancer invasion and M2 macrophages polarization. CONCLUSION: Collectively, KLF14 suppressed breast cancer cell invasion and M2 macrophage polarization through modulating SOCS3/RhoA/Rock/STAT3 signaling, and these findings would provide a new potential target against breast cancer.

MicroRNA-139-5p Suppresses Cell Malignant Behaviors in Breast Cancer through Targeting MEX3A.

OBJECTIVE: The study was designed to evaluate the underlying mechanism of microRNA-139-5p in breast cancer (BC). METHODS: Expression statuses of microRNA-139-5p and MEX3A were measured by qRT-PCR and western blotting. The anticancer effect of microRNA-139-5p in vitro was tested by a set of assays. Interaction between microRNA-139-5p and MEX3A was validated by dual-luciferase detection. RESULTS: MicroRNA-139-5p expression in BC cells was obviously low, while MEX3A was significantly overexpressed. MicroRNA-139-5p restrained proliferative, invasive, and migratory abilities of BC cells and increased apoptosis level of BC cells, while MEX3A exerted a promoting effect on BC cell growth. Dual-luciferase reporter detection confirmed that microRNA-139-5p bound to MEX3A 3'-UTR. CONCLUSIONS: MicroRNA-139-5p inhibited the development of BC by targeting MEX3A. MicroRNA-139-5p/MEX3A may be a target for BC therapy.