MiR-940 Inhibited Cell Growth and Migration in Triple-Negative Breast Cancer.

BACKGROUND Breast cancer is the main type of cancer in women, and triple-negative breast cancer (TNBC) is a unique subtype of breast cancer. The expression of miR-940 has been shown to play an important role in various cancers; however, the role of miR-940 in TNBC remains unknown. MATERIAL AND METHODS The expression of miR-940 in TNBC tissues or cells were tested by qRT-PCR; the expression of miR-940 in cells were overexpressed by miR-940 mimics, and suppressed by anti-miR-940. Bioinformatics algorithms from TargetScanHuman were used to predict the target genes of miR-940. The interaction between miR-940 and ZNF24 was confirmed by dual luciferase assays. The protein level was assayed by Western blot. RESULTS TNBC tissues and cells showed lower miR-940 levels. CONCLUSIONS MiR-940 inhibited cellular proliferation and migration in TNBC.

Systematic analyses of key genes and pathways in the development of invasive breast cancer.

BACKGROUND: Ductal carcinoma in situ (DCIS) is a common type of non-invasive breast cancer and can sometimes progress into invasive breast cancer (IBC). Identification of the critical genes and biological processes specifically and/or commonly changed in DCIS or IBC can help us understand more about breast cancer development and provide more critical targets and signal transduction pathways for the diagnosis and treatments for breast cancer patients. AIM AND METHODS: We aimed to gain more understanding about the whole process of IBC development, especially in the early stage. Here we systematically analyzed an online breast cancer patient database to identify those significantly changed genes and biological processes in epithelium from normal stage to DCIS stage or from DCIS stage to IBC stage. RESULTS: 344 specific genes, such as FN1, AURKA and HSPA8, were found to be significantly changed (both upregulated and downregulated) in DCIS group in comparison with normal tissue group, which represents the gene profile changes in early stage of breast cancer development. Meanwhile, 304 specific genes were significantly changed (both upregulated and downregulated) in IBC group in comparison with normal tissue group, which represents the gene profile changes in late stage of breast cancer development. Importantly, seven genes were identified to have consistent changes in both early stage and late stage, indicating they might play "driving" roles in the breast cancer development. Of these 7 genes, 5 have been shown to be involved in breast cancer progression by previous studies, which demonstrates the validity of our analyses. Notably, DNAPTP3 was identified for the first time to play an oncogenic role in breast cancer development. In the GO term analyses, cell cycle genes was found to play more important roles in the early stage while biological adhesion was indicated to be more specifically involved in late stage of breast cancer development. SIGNIFICANCE: Our systematic analyses provide better understanding of the unique gene profiles and biological processes during the breast cancer development and identify more potentially important targets for future studies, such as DNAPTP3.

Knockdown of ubiquitin protein ligase E3A affects proliferation and invasion, and induces apoptosis of breast cancer cells through regulation of annexin A2.

The present study used RNA interference (RNAi) to study how the expression of annexin A2 was affected by ubiquitin protein ligase E3A (UBE3A). In addition, the proliferation, apoptosis and invasiveness of BT-549 breast cancer cells was studied following knockdown of UBE3A. Three pairs of small interfering RNA (siRNA) fragments targeting UBE3A were designed and transfected into the BT-549 cells. The effects of silencing UBE3A were detected by reverse transcription-polymerase chain reaction and western blotting, and the same methods were used to detect the expression levels of annexin A2. Cell proliferation was determined using the Cell Counting kit-8, and flow cytometry and a Transwell chamber assay were used to assess the rate of cell apoptosis and invasion, respectively. Following transfection with the three siRNAs targeting UBE3A for 72 h, the mRNA expression levels of UBE3A were downregulated, as compared with those in the untreated groups, and siRNA1 was the shown to be the most effective siRNA for silencing UBE3A expression. The protein expression levels were concordant with the mRNA expression levels of UBE3A. In addition, the mRNA and protein expression levels of annexin A2 were downregulated. Cellular proliferation and invasion of the siRNA1 group was inhibited as compared with those in the untreated groups, and apoptosis of UBE3A-siRNA1 cells was increased as compared with that in the untreated groups. The results of the present study indicated that UBE3A may regulate the expression of annexin A2, resulting in promotion of proliferation and invasion and suppression of apoptosis in BT-549 cells.

Overexpression of annexin A2 is associated with abnormal ubiquitination in breast cancer.

Abnormal expression of annexin A2 contributes to metastasis and infiltration of cancer cells. To elucidate the cause of abnormal expression of annexin A2, Western blotting, immunoproteomics and immunohistochemical staining were performed to analyze differentially ubiquitinated proteins between fresh breast cancer tissue and its adjacent normal breast tissue from five female volunteers. We detected an ubiquitinated protein that was up-regulated in the cancer tissue, which was further identified as annexin A2 by mass spectrometry. These results suggest that abnormal ubiquitination and/or degradation of annexin A2 may lead to presence of annexin A2 at high level, which may further promote metastasis and infiltration of the breast cancer cells.

Over-expression of genes and proteins of ubiquitin specific peptidases (USPs) and proteasome subunits (PSs) in breast cancer tissue observed by the methods of RFDD-PCR and proteomics.

The ubiquitin-proteasome system facilitates the degradation of damaged proteins and regulators of growth and stress response. Alterations in this proteolytic system are associated with a variety of human pathologies. By restriction fragment differential display polymerase chain reaction (RFDD-PCR) and matrix-assisted laser desorption/ionization tandem time-of-flight mass spectrometry (MALDI-TOF-TOF MS) based on two-dimensional polyacrylamide gel electrophoresis (2-DE), differentially expressed genes and proteins of ubiquitin specific proteases (USPs), proteasome subuinits (PSs) and ubiquitin protein ligase E3A (UBE3A) were analyzed between breast cancer and adjacent normal tissues. Some of them were further verified as over-expression by immunohistochemical stain. Five genes of proteasome subunits (PSs), including PSMB5, PSMD1, PSMD2, PSMD8 and PSMD11, four genes of USPs, including USP9X, USP9Y, USP10 and USP25, and ubiquitin protein ligase E3A (UBE3A) were over-expressed (>3-fold) in breast cancer tissue compared to adjacent normal tissue, and over-expression (>4-fold) of proteins of PSMA1 and SMT3A were observed in breast cancer tissue. PSMD8, PSMD11 and UBE3A were further verified as over-expression by immunohistochemical stain. The action of ubiquitin-proteasome system were obviously enhanced in breast cancer, and selectively intervention in action of ubiquitin-proteasome system may be a useful method of treating human breast cancer.

Comparative proteome analysis of breast cancer and adjacent normal breast tissues in human.

Two-dimensional polyacrylamide gel electrophoresis (2D-PAGE) and matrix-assisted laser desorption/ionization tandem time-of-flight mass spectrometry (MALDI-TOF/TOF-MS), incorporated with online database searching, were performed to investigate differential proteins of breast cancer and adjacent normal breast tissues. Considering that serum albumin is abundantly presented in normal control samples, 15 differential spots detected in 11 out of 12 (91.7%) breast cancer samples were identified by online SIENA-2DPAGE database searching and MALDI-TOF/TOF-MS analysis. The results indicate that pathological changes of breast cancer are concerned with augmentation of substance metabolism, promotion of proteolytic activity, decline of activity of some inhibitors of enzymes, and so on. Some important proteins involved in the pathological process of breast cancer with changed expression may be useful biomarkers, such as alpha-1-antitrypsin, EF-1-beta, cathepsin D, TCTP, SMT3A, RPS12, and PSMA1, among which SMT3A, RPS12, and PSMA1 were first reported for breast cancer in this study.

[Relationship of oncogene C-erbB2 expression to ER, PR and PS2 in breast cancer and its prognostic significance].

OBJECTIVE: To explore the expression of oncogene C-erbB2 in breast cancer, its relationship to estrogen receptor (ER), progesterone receptor (PR) and PS2 and the prognostic significance. METHODS: The expression of oncogene C-erbB2 in 245 cases with breast cancer was detected with immunohistochemical technique (LsAB). RESULTS: Expression of oncogene C-erbB2 was found in 60% cases of breast cancer. Tumors positive for C-erbB2 were 45.19% and 71.55% in ER positive group and ER negative group respectively, while tumors positive for C-erbB2 were 48.08% and 70.43% in PR positive group and PR negative group respectively. The expression of the C-erbB2 was 23.26% in group of PS2 positive and 50.75% in group of PS2 negative (P < 0.05). No significant association of C-erbB2 expression with age and tumor size was noted(P > 0.05), but its expression in breast cancer was correlated with advanced clinical stage, high histological grade, axillary lymph node involvement (P < 0.05). CONCLUSION: C-erbB2 would be helpful to the evaluation of prognosis and treatment in breast cancer.