The characteristic genetic abnormality of neuroendocrine neoplasms (NENs), a heterogeneous group of tumors found in various organs, remains to be identified. Here, based on the analysis of the splicing variants of an oncogene Focal Adhesion Kinase (FAK) in The Cancer Genome Atlas datasets that contain 9193 patients of 33 cancer subtypes, we found that Box 6/Box 7-containing FAK variants (FAK^6/7) were observed in 7 (87.5%) of 8 pancreatic neuroendocrine carcinomas and 20 (11.76%) of 170 pancreatic ductal adenocarcinomas (PDACs). We tested FAK variants in 157 tumor samples collected from Chinese patients with pancreatic tumors, and found that FAK^6/7 was positive in 34 (75.6%) of 45 pancreatic NENs, 19 (47.5%) of 40 pancreatic solid pseudopapillary neoplasms, and 2 (2.9%) of 69 PDACs. We further tested FAK splicing variants in breast neuroendocrine carcinoma (BrNECs), and found that FAK^6/7 was positive in 14 (93.3%) of 15 BrNECs but 0 in 23 non-NEC breast cancers. We explored the underlying mechanisms and found that a splicing factor serine/arginine repetitive matrix protein 4 (SRRM4) was overexpressed in FAK^6/7-positive pancreatic tumors and breast tumors, which promoted the formation of FAK^6/7 in cells. These results suggested that FAK^6/7 could be a biomarker of NENs and represent a potential therapeutic target for these orphan diseases.
Female ; Humans ; Alternative Splicing ; Breast Neoplasms/metabolism* ; Carcinoma, Pancreatic Ductal/pathology* ; Focal Adhesion Protein-Tyrosine Kinases/therapeutic use* ; Nerve Tissue Proteins/genetics* ; Neuroendocrine Tumors/genetics* ; Oncogenes ; Pancreatic Neoplasms/metabolism*

YWHAE gene is located on chromosome 17p13.3, and its product 14-3-3epsilon protein belongs to 14-3-3 protein family. As a molecular scaffold, YWHAE participates in biological processes such as cell adhesion, cell cycle regulation, signal transduction and malignant transformation, and is closely related to many diseases. Overexpression of YWHAE in breast cancer can increase the ability of proliferation, migration and invasion of breast cancer cells. In gastric cancer, YWHAE acts as a negative regulator of MYC and CDC25B, which reduces their expression and inhibits the proliferation, migration, and invasion of gastric cancer cells, and enhances YWHAE-mediated transactivation of NF-κB through CagA. In colorectal cancer, YWHAE lncRNA, as a sponge molecule of miR-323a-3p and miR-532-5p, can compete for endogenous RNA through direct interaction with miR-323a-3p and miR-532-5p, thus up-regulating K-RAS/ERK/1/2 and PI3K-AKT signaling pathways and promoting the cell cycle progression of the colorectal cancer. YWHAE not only mediates tumorigenesis as a competitive endogenous RNA, but also affects gene expression through chromosome variation. For example, the FAM22B-YWHAE fusion gene caused by t(10; 17) (q22; p13) may be associated with the development of endometrial stromal sarcoma. At the same time, the fusion transcript of YWHAE and NUTM2B/E may also lead to the occurrence of endometrial stromal sarcoma. To understand the relationship between YWHAE, NUTM2A, and NUTM2B gene rearrangement/fusion and malignant tumor, YWHAE-FAM22 fusion gene/translocation and tumor, YWHAE gene polymorphism and mental illness, as well as the relationship between 17p13.3 region change and disease occurrence. It provides new idea and basis for understanding the effect of YWHAE gene molecular mechanism and genetic variation on the disease progression, and for the targeted for the diseases.
14-3-3 Proteins/metabolism* ; Breast Neoplasms/genetics* ; Cell Line, Tumor ; Cell Proliferation/genetics* ; Cell Transformation, Neoplastic/genetics* ; Colorectal Neoplasms/genetics* ; Endometrial Neoplasms ; Female ; Gene Expression Regulation, Neoplastic ; Humans ; MicroRNAs/genetics* ; Phosphatidylinositol 3-Kinases/metabolism* ; Sarcoma, Endometrial Stromal/pathology* ; Stomach Neoplasms/genetics* ; Transcription Factors/genetics* ; Translocation, Genetic

OBJECTIVE: To investigate the regulatory effect of miR-4324 on ankyrin 2(Talin2) expression and biological behaviors of breast cancer cells and the clinical implications of changes in miR-4324 and Talin2 expressions in breast cancer. METHODS: In breast cancer and adjacent tissues, the expressions of Talin2 and miR-4324 were examined with immunohistochemistry and qRT-PCR, respectively and the association of Talin2 expression levels with the prognosis and clinicopathological features of breast cancer patients was analyzed.The human breast cancer cell line SKBR-3 was transfected with miR-4324 mimic, miR-4324 inhibitor, si-Talin2, or both miR-4324 inhibitor and si-Talin2, and the changes in biological behaviors of the cells were examined; the cellular expression of Talin2at the mRNA and protein levels were detected with qRT-PCR and Western blotting.Dual luciferase reporter gene assay was used to verify the targeting relationship between miR-4324 and Talin2.The effect of miR-4324-mediated regulation of Talin2 on SKBR-3 cell migration was assessed using Transwell assays. RESULTS: Talin2 expression was significantly higher in breast cancer tissues than in the adjacent tissues, and its expression level was correlated with lymph node metastasis and high HER-2 expression in breast cancer (P < 0.05) but not with the patient's age, clinical stage, histological grade or expressions of estrogen and progesterone receptors (P >0.05).The expression of miR-4324 was significantly reduced in breast cancer tissues as compared with the adjacent tissues (P < 0.01).In SKBR-3 cells, transfection with miR-4324 mimics significantly inhibited proliferation, migration and invasion (P < 0.05) and promoted apoptosis (P < 0.01) of the cells.Dual luciferase reporter gene assay confirmed that cotransfection with miR-4324 mimics significantly reduced luciferase activity of Talin2-3'-UTR WT reporter plasmid (P < 0.05).Transfection of the cells with miR-4324 mimics significantly reduced mRNA and protein expressions of Talin2(P < 0.05).Transwell migration assay showed that the migration ability of SKBR-3 cells was significantly enhanced after transfection with miR-4324 inhibitor (P < 0.01), lowered after transfection with si-Talin2(P < 0.01), and maintained at the intermediate level after co-transfection with miR-4324 inhibitor+si-Talin2 group (P < 0.05). CONCLUSIONS High expression of Talin2 is associated with lymph node metastasis and HER-2 overexpression in breast cancer patients.Down-regulation of miR-4324 inhibits the proliferation, invasion and migration and induces apoptosis of breast cancer cells, and the inhibitory effect of miR-4324 knockdown on breast cancer cell migration is mediated probably by targeted inhibition of Talin2 expression.
Female ; Humans ; Breast Neoplasms/pathology* ; Cell Line, Tumor ; Cell Movement/genetics* ; Cell Proliferation/genetics* ; Gene Expression Regulation, Neoplastic ; Luciferases/genetics* ; Lymphatic Metastasis ; MicroRNAs/metabolism* ; Neoplasm Invasiveness/genetics* ; RNA, Messenger

BACKGROUND: Ubiquitin-conjugating enzyme E2C (UBE2C) has been shown to be associated with the occurrence of various cancers and involved in many tumorigenic processes. This study aimed to investigate the specific molecular mechanism through which UBE2C affects breast cancer (BC) proliferation. METHODS: BC-related datasets were screened according to filter criteria in the Gene Expression Omnibus (GEO) database and The Cancer Genome Atlas (TCGA) database. Then differentially expressed genes (DEGs) were identified using Venn diagram analysis. By using DEGs, we conducted the following analyses including Gene ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG), protein-protein interaction (PPI), and survival analysis, and then validated the function of the hub gene UBE2C using quantitative reverse transcription-polymerase chain reaction (RT-qPCR), cell counting kit-8 (CCK-8) assay, transwell assay, and Western blot assay. RESULTS: In total, 151 DEGs were identified from the GEO and TCGA databases. The results of GO analysis demonstrated that the DEGs were significantly enriched with mitotic nuclear division, lipid droplet, and organic acid-binding. KEGG analysis showed that the peroxisome proliferators-activated receptor (PPAR) signaling pathway, regulation of lipolysis in adipocytes, and proximal tubule bicarbonate reclamation were significantly enriched in the signal transduction pathway category. The top three hub genes that resulted from the PPI network were FOXM1, UBE2C, and CDKN3. The results of survival analysis showed a close relationship between UBE2C and BC. The results of CCK-8 and transwell assays suggested that the proliferation and invasion of UBE2C knockdown cells were significantly inhibited (P < 0.050). The results of Western blot assay showed that the level of phosphorylated phosphatase and tensin homology deleted on chromosome 10 (p-PTEN) was obviously increased (P < 0.050), whereas the levels of phosphorylated protein kinase B (p-AKT), phosphorylated mammalian target of rapamycin (p-mTOR), and hypoxia-inducible factor-1 alpha (HIF-1α) were dramatically decreased (P < 0.050) in the UBE2C knockdown cell. CONCLUSION UBE2C can promote BC proliferation by activating the AKT/mTOR signaling pathway.
Biomarkers, Tumor ; Breast Neoplasms/pathology* ; Cell Proliferation/genetics* ; Computational Biology ; Female ; Gene Expression Regulation, Neoplastic ; Humans ; Proto-Oncogene Proteins c-akt/genetics* ; Signal Transduction/genetics* ; TOR Serine-Threonine Kinases/genetics* ; Ubiquitin-Conjugating Enzymes/metabolism*

OBJECTIVE: To study the effects of the overexpression of autophagy-related gene 3 (ATG3) on autophagy and salinomycin-induced apoptosis in breast cancer cells and explore the underlying mechanisms. METHODS: We used the lentivirus approach to establish a breast cancer cell line with stable overexpression of ATG3. Western blotting, immunofluorescence staining and transmission electron microscopy were used to analyze the effect of ATG3 overexpression on autophagy in breast cancer MCF-7 cells. Using the AKT/mTOR agonists SC79 and MHY1485, we analyzed the effect of AKT/mTOR signal pathway activation on ATG3 overexpression-induced autophagy. Western blotting and flow cytometry were used to analyze the effect of autophagy on apoptosis of the ATG3-overexpressing cells treated with salinomycin and 3-MA (an autophagy inhibitor). RESULTS: In ATG3-overexpressing MCF-7 cells, ATG3 overexpression obviously promoted autophagy, inhibited the AKT/mTOR signaling pathway, significantly weakened salinomycin-induced apoptosis ( < 0.01), caused significant reduction of the levels of the pro-apoptotic proteins cleaved-caspase 3 ( < 0.01) and Bax ( < 0.05), and enhanced the expression of the anti-apoptotic protein Bcl-2 ( < 0.05). The inhibition of autophagy obviously weakened the inhibitory effect of ATG3 overexpression on salinomycin-induced apoptosis. CONCLUSIONS ATG3 overexpression promotes autophagy possibly by inhibiting the AKT/mTOR signaling pathway to decrease salinomycin-induced apoptosis in MCF-7 cells, suggesting that autophagy induction might be one of the mechanisms of drug resistance in breast cancer cells.
Acetates ; pharmacology ; Apoptosis ; drug effects ; genetics ; Autophagy ; drug effects ; Autophagy-Related Proteins ; metabolism ; Benzopyrans ; pharmacology ; Breast Neoplasms ; metabolism ; pathology ; Cell Line, Tumor ; Cell Proliferation ; Drug Resistance, Neoplasm ; Female ; Gene Expression Regulation ; Humans ; MCF-7 Cells ; Morpholines ; pharmacology ; Proto-Oncogene Proteins c-akt ; antagonists & inhibitors ; metabolism ; Pyrans ; pharmacology ; TOR Serine-Threonine Kinases ; antagonists & inhibitors ; metabolism ; Triazines ; pharmacology ; Ubiquitin-Conjugating Enzymes ; metabolism

Breast Neoplasms ; metabolism ; pathology ; Cell Line, Tumor ; Cell Proliferation ; drug effects ; Down-Regulation ; drug effects ; Female ; Guanine Nucleotide Exchange Factors ; antagonists & inhibitors ; genetics ; metabolism ; Humans ; Indoles ; pharmacology ; MCF-7 Cells ; Maleimides ; pharmacology ; Protein Isoforms ; genetics ; metabolism ; Protein Kinase C ; antagonists & inhibitors ; genetics ; metabolism ; RNA Interference ; RNA, Small Interfering ; metabolism ; Receptor, ErbB-2 ; genetics ; metabolism ; Tetradecanoylphorbol Acetate ; toxicity

Cancer stem cells (CSCs), a subpopulation of cancer cells with ability of initiating tumorigenesis, exist in many kinds of tumors including breast cancer. Cancer stem cells contribute to treatment resistance and relapse. Conventional treatments only kill differentiated cancer cells, but spare CSCs. Combining conventional treatments with therapeutic drugs targeting to CSCs will eradicate cancer cells more efficiently. Studying the molecular mechanisms of CSCs regulation is essential for developing new therapeutic strategies. Growing evidences showed CSCs are regulated by non-coding RNA (ncRNA) including microRNAs and long non-coding RNAs (lncRNAs), and histone-modifiers, such as let-7, miR-93, miR-100, HOTAIR, Bmi-1 and EZH2. Herein we review the roles of microRNAs, lncRNAs and histone-modifiers especially Polycomb family proteins in regulating breast cancer stem cells (BCSCs).
Breast Neoplasms ; genetics ; metabolism ; pathology ; Histones ; metabolism ; Humans ; Neoplastic Stem Cells ; metabolism ; RNA, Untranslated ; genetics ; metabolism

Breast Neoplasms ; metabolism ; pathology ; Female ; Humans ; Ki-67 Antigen ; genetics ; metabolism

Basal-type breast cancers are among the most aggressive and deadly breast cancer subtypes, displaying a high metastatic ability associated with mesenchymal features. However, the molecular mechanisms underlying the maintenance of mesenchymal phenotypes of basal-type breast cancer cells remain obscure. Here, we report that KRAS is a critical regulator for the maintenance of mesenchymal features in basal-type breast cancer cells. KRAS is preferentially activated in basal-type breast cancer cells as compared with luminal type. By loss and gain of KRAS, we found that KRAS is necessary and sufficient for the maintenance of mesenchymal phenotypes and metastatic ability through SLUG expression. Taken together, this study demonstrates that KRAS is a critical regulator for the metastatic behavior associated with mesenchymal features of breast cancer cells, implicating a novel therapeutic target for basal-type breast cancer.
Animals ; Breast Neoplasms/*genetics/metabolism/pathology ; Cell Line, Tumor ; Cell Transformation, Neoplastic/genetics/metabolism ; Disease Models, Animal ; Epithelial-Mesenchymal Transition/*genetics ; Female ; Gene Expression Regulation, Neoplastic ; Gene Knockdown Techniques ; Heterografts ; Humans ; Neoplasm Invasiveness ; Neoplasm Metastasis ; Phenotype ; Proto-Oncogene Proteins/*genetics/metabolism ; *Transcriptional Activation ; ras Proteins/*genetics/metabolism

PURPOSE: The aims of this study were to compare the expression of sarcosine metabolism-related proteins between invasive lobular carcinoma (ILC) and invasive ductal carcinoma (IDC) and to determine the implications of these results. MATERIALS AND METHODS: Tissue microarrays were constructed, containing 30 samples from normal breast tissue, 114 samples from patients with ILC, and 692 samples from patients with IDC. Immunohistochemical staining was performed to examine the expression of sarcosine metabolism-related proteins [glycine N-methyltransferase, sarcosine dehydrogenase, and l-pipecolic acid oxidase (PIPOX)]. RESULTS: The sarcosine metabolic phenotype differed between ILC and IDC (p<0.001). In IDC, sarcosine metabolic phenotype was distributed as null type (61.7%)>low sarcosine type (30.4%)>high sarcosine type (5.0%)>intermediate type (2.9%). However, in ILC, the sarcosine metabolic phenotype was distributed as low sarcosine type (61.4%)>null type (32.5%)>intermediate type (5.3%)>high sarcosine type (0.9%). PIPOX showed higher expression in ILC than in IDC (p<0.001) and correlated with androgen receptor (AR) positivity (p=0.001) in ILC. CONCLUSION: Expression of sarcosine metabolism-related proteins differed between ILC and IDC. Low sarcosine type was the majority sarcosine metabolic phenotype of ILC. PIPOX expression was predominant in ILC and correlated with AR positivity.
Adult ; Breast/pathology ; Breast Neoplasms/*metabolism/pathology ; Carcinoma, Ductal, Breast/*metabolism/pathology ; Carcinoma, Lobular/*metabolism ; Female ; Humans ; Immunohistochemistry ; Middle Aged ; Multivariate Analysis ; Phenotype ; Proportional Hazards Models ; Regression Analysis ; Retrospective Studies ; Sarcosine/genetics/*metabolism ; Tissue Array Analysis