MicroRNA-630 inhibits breast cancer progression by directly targeting BMI1

MicroRNAs (miRNAs) play critical roles in breast cancer cell biological processes, including proliferation and apoptosis by inhibiting the expression of their target genes. Herein, we reported that miR-630 overexpression initiates apoptosis, blocks cell cycle progression and suppresses cell proliferation in breast cancer cells. Furthermore, BMI1, a member of polycomb group family, was identified as a direct target of miR-630, and there was a negative correlation between the expression levels of BMI1 and miR-630 in human breast cancer samples. With a series of biology approaches, subsequently, we proved that BMI1 was a functional downstream target of miR-630 and mediated the property of miR-630-dependent inhibition of breast cancer progression. Taken together, these findings provide further evidence on the tumor-suppression function of miR-630 in breast cancer, and clarify BMI1 as a novel functional target gene of miR-630.     

microRNA-1225 inhibit apoptosis of pancreatic cancer cells via targeting JAK1

The microRNA miRNA-1225-5p (miR-1225) is known as an essential modulator of the development of multiple cancers and other biological reactions. However, the understanding of its contribution to pancreatic cancer (PC) is insufficient. The effects of miR-1225 on PC cell survival and tumorigenesis in vivo as well as on the modulation of cell apoptosis were investigated. The expression of miR-1225 was upregulated in 20 human LC samples from acute myeloid leukemia patients with adverse prognosis and poor responses to therapy as well as in several human PC cell lines, as compared to that in healthy tissues, normal tissues, and normal pancreatic cells. In contrast, Janus kinase 1 (JAK1) expression was downregulated in human-derived PC samples and PC cell lines. EdU staining demonstrated that the aberrant expression of miR-1225 impaired the proliferation and survival of these two PC cell lines. The depletion of miR-1225 expression increased the apoptosis of both PANC-1 and AsPC-1 cells, as revealed by the TdT-mediated dUTP nick end labeling (TUNEL) staining and flow cytometry results. The results of dual-luciferase reporter assay indicated that miR-1225 targeted the 3′-untranslated region of JAK1 for silencing. Silencing of JAK1 expression counteracted the suppressive influence of miR-1225 depletion in PC cells. Thus, these results offer an insight into the biological and molecular mechanisms underlying the development of PC and provide potential strategies for PC treatment.     

ADAM9 silencing inhibits breast tumor cell invasion in vitro

ADAM9 (A Disintegrin And Metalloproteinase 9) is a member of the ADAM protein family which contains a disintegrin domain. This protein family plays key roles in many physiological processes, including fertilization, migration, and cell survival. The ADAM proteins have also been implicated in various diseases, including cancer. Specifically, ADAM9 has been suggested to be involved in metastasis. To address this question, we generated ADAM9 knockdown clones of MDA-MB-231 breast tumor cells using silencing RNAs that were tested for cell adhesion, proliferation, migration and invasion assays. In RNAi-mediated ADAM9 silenced MDA-MB-231 cells, the expression of ADAM9 was lower from the third to the sixth day after silencing and inhibited tumor cell invasion in matrigel by approximately 72% when compared to control cells, without affecting cell adhesion, proliferation or migration. In conclusion, the generation of MDA-MB-231 knockdown clones lacking ADAM9 expression inhibited tumor cell invasion in vitro, suggesting that ADAM9 is an important molecule in the processes of invasion and metastasis.     

Oncogenic microRNA-765 promotes the growth and metastasis of breast carcinoma by directly targeting ING4

Previous investigations have proved that microRNA (miR)-765 is significantly overexpressed in multiple tumor types. Nevertheless, the underlying molecular mechanism of miR-765 in mediating breast carcinoma cell growth and metastasis remains unclear. Quantitative real-time polymerase chain reaction was used to determine the levels of miR-765 and inhibitor of growth 4 (ING4) in breast carcinoma tissues and breast carcinoma cells. Cell proliferation, colony formation, wound healing, and Transwell invasion assays were used to analysis the role of miR-765 on breast carcinoma cell growth and aggressiveness. The expressions of ING4 were determined using Western blot analysis and immunohistochemical staining. The direct target of ING4 and miR-765 was confirmed using the luciferase reporter assay. Nude mice were subcutaneously implanted with miR-765 inhibitor transfected MDA-MB-231 cells to determine the potential role of miR-765 in tumor growth in vivo. We observed that miR-765 is overexpressed in breast carcinoma tissue and breast cancer cells. By using luciferase reporter gene bioassay, we find that ING4 is the direct target of miR-765 in breast carcinoma. The level of ING4 is inversely associated with the level of miR-765. The gain-of-function and loss-of-function experiments in vitro indicate that the downregulation of miR-765 suppresses the growth, mobility, and invasion abilities of breast cancer cells by inhibiting ING4. In addition, overexpression of ING4 suppresses the aggressiveness of the MDA-BA-231 cell that is induced by miR-761 in vitro. In this study, we prove that miR-765 regulates the growth and metastasis of breast cancer via modulating miR-765-ING4-negative feedback loop.     

Inhibitory monoclonal antibody targeting ADAM17 expressed on cancer cells

ADAM17 is upregulated in many cancers and in turn activates signaling pathways, including EGFR/ErbB, as well as those underlying resistance to targeted anti-EGFR therapies. Due to its central role in oncogenic pathways and drug resistance mechanisms, specific and efficacious monoclonal antibodies against ADAM17 could be useful for a broad patient population with solid tumors. Hence, we describe here an inhibitory anti-ADAM17 monoclonal antibody, named D8P1C1, that preferentially recognizes ADAM17 on cancer cells. D8P1C1 inhibits the catalytic activity of ADAM17 in a fluorescence-based peptide cleavage assay, as well as the proliferation of a range of cancer cell lines, including breast, ovarian, glioma, colon and the lung adenocarcinoma. In mouse models of triple-negative breast cancer and ovarian cancer, treatment with the mAb results in 78% and 45% tumor growth inhibition, respectively. Negative staining electron microscopy analysis of the ADAM17 ectodomain in complex with D8P1C1 reveals that the mAb binds the ADAM17 protease domain, consistent with its ability to inhibit the ADAM17 catalytic activity. Collectively, our results demonstrate the therapeutic potential of the D8P1C1 mAb to treat solid tumors.     

Dysregulated circRNA_100876 suppresses proliferation of osteosarcoma cancer cells by targeting microRNA-136

The aim of this study was to explore the regulatory mechanism of circRNA_100876/ microRNA-136 (miR-136) axis in the development and progression of osteosarcoma cancer. Quantitative real-time polymerase chain reaction (RT-qPCR) was used to evaluate the expression levels of circRNA_100876 and miR-136 in osteosarcoma cancer samples and the adjacent nontumor tissues. Then, cell proliferation, cell cycle, apoptosis, and migration of circRNA_100876-knocked down cells were analyzed by in vitro and in vivo experiments, using cell counting kit-8 (CCK-8), flow cytometry, and transwell and tumorigenesis assays. The expression of circRNA_100876 was found to be significantly upregulated in osteosarcoma, and was closely correlated with the tumor size and tumor differentiation degree. In addition, the knockdown of circRNA_100876 could significantly inhibit the tumor growth, both in vitro and in vivo. Flow cytometry and Western blot analysis results showed that the downregulation of circRNA_100876 inhibited osteosarcoma cells proliferation via promoting apoptosis and arresting more cells in the G2/M stage, as suggested by the expression of apoptosis and cell cycle pathway-related proteins, which changed consistently. Furthermore, the level of miR-136 was negatively correlated with the expression of circRNA_100876, and miR-136 inhibitors were able to reverse the suppression of cell proliferation induced by silencing circRNA_100876. Our study demonstrates that the dysregulation of circRNA_100876 could induce apoptosis and arrest the cell cycle at G2/M stage, followed by suppression of cell proliferation in osteosarcoma, while silencing miR-136 could restore the cell growth. Therefore, circRNA_100876 might serve as a promising biomarker and treatment target for osteosarcoma.     

Estradiol stabilizes the 105-kDa phospho-form of the adhesion docking protein NEDD9 and suppresses NEDD9-dependent cell spreading in breast cancer cells

Recent data suggest that the adhesion docking protein NEDD9/HEF1/Cas-L is a critical regulator of adhesion-dependent signalling pathways during mammary tumour development. Multiple phosphorylation modifications of NEDD9 regulate interaction with downstream protein partners, thus the regulation of NEDD9 phospho-forms is an important point of control for NEDD9 function. As estradiol (E2) plays a central role in the development and progression of breast cancer, we have investigated NEDD9 phospho-form regulation in MCF-7 estrogen receptor (ER)-positive breast cancer cells in response to estrogen. We find that levels of the 105-kDa NEDD9 phospho-form are significantly increased after 3 days of estrogen exposure, and this is suppressed by the anti-estrogen tamoxifen. Analysis of protein decay kinetics following treatment with the protein synthesis inhibitor cycloheximide indicates that increased 105-kDa levels are due to a slower rate of protein decay. Moreover, exogenous expression of NEDD9 failed to induce spreading in the presence of E2, and this was reversed by tamoxifen treatment. Finally, we show that the 105-kDa NEDD9 phospho-form appears to predominate in ER-positive versus ER-negative breast cancer cell lines. Taken together, our results suggest that estradiol may suppress phospho-form-specific functions of NEDD9.     

Recombinant disintegrin domain of human ADAM9 inhibits migration and invasion of DU145 prostate tumor cells

One of the most important features of malignant cells is their capacity to invade adjacent tissues and metastasize to distant organs. This process involves the creation, by tumor and stroma cells, of a specific microenvironment, suitable for proliferation, migration and invasion of tumor cells. The ADAM family of proteins has been involved in these processes. This work aimed to investigate the role of the recombinant disintegrin domain of the human ADAM9 (rADAM9D) on the adhesive and mobility properties of DU145 prostate tumor cells. rADAM9D was able to support DU145 cell adhesion, inhibit the migration of DU145 cells, as well as the invasion of this cell line through matrigel in vitro. Overall this work demonstrates that rADAM9D induces specific cellular migratory properties when compared with different constructs having additional domains, specially those of metalloproteinase and cysteine-rich domains. Furthermore, we showed that rADAM9D was able to inhibit cell adhesion, migration and invasion mainly through interacting with α6β1 in DU145 tumor cell line. These results may contribute to the development of new therapeutic strategies for prostate cancer.     

Recombinant disintegrin domain of human ADAM9 inhibits migration and invasion of DU145 prostate tumor cells

One of the most important features of malignant cells is their capacity to invade adjacent tissues and metastasize to distant organs. This process involves the creation, by tumor and stroma cells, of a specific microenvironment, suitable for proliferation, migration and invasion of tumor cells. The ADAM family of proteins has been involved in these processes. This work aimed to investigate the role of the recombinant disintegrin domain of the human ADAM9 (rADAM9D) on the adhesive and mobility properties of DU145 prostate tumor cells. rADAM9D was able to support DU145 cell adhesion, inhibit the migration of DU145 cells, as well as the invasion of this cell line through matrigel in vitro. Overall this work demonstrates that rADAM9D induces specific cellular migratory properties when compared with different constructs having additional domains, specially those of metalloproteinase and cysteine-rich domains. Furthermore, we showed that rADAM9D was able to inhibit cell adhesion, migration and invasion mainly through interacting with α6β1 in DU145 tumor cell line. These results may contribute to the development of new therapeutic strategies for prostate cancer.     

microRNA-802 inhibits cell proliferation and induces apoptosis in human cervical cancer by targeting serine/arginine-rich splicing factor 9

microRNAs (miRNAs) play crucial roles in cancer development and progression by targeting mRNAs for degradation and/or translational repression. microRNA-802 (miR-802) has been reported as a tumor suppressor and its deregulation is observed in various human cancers. However, the prognostic value of miR-802 and its underlying mechanisms involved in human cervical cancer are poorly investigated. The purposes of this study were to explore the role of miR-802 in cervical cancer and to clarify the regulation of serine/arginine-rich splicing factor 9 (SRSF9) by miR-802. Here, we found that miR-802 was downregulated in both cervical cancer tissues and cell lines. Transfection of a miR-802 mimic into cervical cancer cells inhibited their proliferation and colony formation, and promoted cell cycle arrest at the G0/G1 phase and cell apoptosis. In addition, we found that miR-802 could directly target the 3′-untranslated region of SRSF9 and suppress SRSF9 expression. Rescue experiments revealed that overexpression of SRSF9 partially reversed the inhibition effect of miR-802 in cervical cancer cells. Overall, these findings demonstrate that miR-802 functions as a tumor suppressor in cervical cancer by targeting SRSF9, suggesting that miR-802 might serve as a potential therapeutic target in cervical cancer.     

MicroRNA-188-5p promotes apoptosis and inhibits cell proliferation of breast cancer cells via the MAPK signaling pathway by targeting Rap2c

Breast cancer is a common malignancy that is highly lethal with poor survival rates and immature therapeutics that urgently needs more effective and efficient therapies. MicroRNAs are intrinsically involved in different cancer remedies, but their mechanism in breast cancer has not been elucidated for prospective treatment. The function and mechanism of microRNA-188-5p (miR-188) have not been thoroughly investigated in breast cancer. In our study, we found that the expression of miR-188 in breast cancer tissues was obviously reduced. Our findings also revealed the abnormal overexpression of miR-188 in 4T1 and MCF-7 cells significantly suppressed cell proliferation and migration and also enhanced apoptosis. miR-188 induced cell cycle arrest in the G1 phase. To illuminate the molecular mechanism of miR-188, Rap2c was screened as a single target gene by bioinformatics database analysis and was further confirmed by dual-luciferase assay. Moreover, Rap2c was found to be a vital molecular switch for the mitogen-activated protein kinase signaling pathway in tumor progression by decreasing apoptosis and promoting proliferation and migration. In conclusion, our results revealed that miR-188 is a cancer progression suppressor and a promising future target for breast cancer therapy.     

Regulation of angiogenesis via Notch signaling in breast cancer and cancer stem cells

Breast cancer angiogenesis is elicited and regulated by a number of factors including the Notch signaling. Notch receptors and ligands are expressed in breast cancer cells as well as in the stromal compartment and have been implicated in carcinogenesis. Signals exchanged between neighboring cells through the Notch pathway can amplify and consolidate molecular differences, which eventually dictate cell fates. Notch signaling and its crosstalk with many signaling pathways play an important role in breast cancer cell growth, migration, invasion, metastasis and angiogenesis, as well as cancer stem cell (CSC) self-renewal. Therefore, significant attention has been paid in recent years toward the development of clinically useful antagonists of Notch signaling. Better understanding of the structure, function and regulation of Notch intracellular signaling pathways, as well as its complex crosstalk with other oncogenic signals in breast cancer cells will be essential to ensure rational design and application of new combinatory therapeutic strategies. Novel opportunities have emerged from the discovery of Notch crosstalk with inflammatory and angiogenic cytokines and their links to CSCs. Combinatory treatments with drugs designed to prevent Notch oncogenic signal crosstalk may be advantageous over λ secretase inhibitors (GSIs) alone. In this review, we focus on the more recent advancements in our knowledge of aberrant Notch signaling contributing to breast cancer angiogenesis, as well as its crosstalk with other factors contributing to angiogenesis and CSCs.     

MiR-126-3p inhibits ovarian cancer proliferation and invasion via targeting PLXNB2

Ovarian cancer is one of the leading malignancies in women and the 5-year survival rate of ovarian cancer still remains poor. In the present study, we aimed to investigate the interaction between the miR-126-3p and PLXNB2 in the progression of ovarian cancer. The qRT-PCR data revealed a reduction of miR-126-3p level in ovarian cancer tissues comparing to the adjacent normal tissues. Over-expression of miR-126-3p in ovarian cancer cells suppressed cell proliferation and invasion and the phosphorylation of AKT and ERK1/2. The cell cycle assay results showed that the over-expression of miR-126-3p induced cells in G1-phase and reduced cells in S-phase. We further performed bioinformatics analysis and luciferase assay to investigate the relationship between miR-126-3p and PLXNB2 in ovarian cancer cells. The results of TargetScan suggested that PLXNB2 is a direct target of miR-126-3p in ovarian cancer cells, and luciferase assay confirmed bioinformatics prediction. Knocking down of PLXNB2 with PLXNB2 siRNA results in repressed ovarian cancer cell proliferation and invasion, and decreased phosphorylation of AKT and ERK1/2, which is similar to the effect of over-expression of miR-126-3p in OC cells. The synergistic effect of combination of miR-126-3p over-expression and PLXNB2 down-regulation on the cell growth viability, cell colony, and cell invasion was also identified. All these findings indicated that miR-126-3p is involved in the progression of ovarian cancer via direct regulating PLXNB2.