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Breast cancer suppressor candidate-1 (BCSC-1; also termed von Willebrand factor A domain containing 5A and LOH11CR2A) is a newly identified candidate tumor suppressor gene that has been implicated in several types of cancer in previous studies. However, there have been few reports about the association between BCSC-1 and human breast cancer in recent years. In the present study, the expression of BCSC-1 in breast cancer was determined by immunohistochemistry (IHC) staining of tissue microarrays and clinical tissue specimens. Subsequently, BCSC-1 gene expression was evaluated in different breast cancer cell lines by quantitative polymerase chain reaction and the MDA-MB-231 cell line was selected for further use in subsequent experiments, due to its low BCSC-1 expression. An MDA-MB-231 cell line with stable overexpression of BCSC-1 was established through transfection with plasmid containing the BCSC-1 gene, and then screening for G418 resistance. Wound-healing, migration and invasion assays were conducted to detect the effect of BCSC-1 on MDA-MB-231 cells. Furthermore, changes in matrix metalloproteinases (MMPs), osteopontin (OPN) and the nuclear factor-κB (NF-κB) pathway were detected in the current study. Additionally, stable silencing of BCSC-1 expression in MCF-7 cells was performed using a lentivirus. The results of IHC indicated that BCSC-1 is expressed at low levels in breast cancer tissues compared with in normal breast tissue. Results of the wound healing, migration and invasion assays demonstrated that BCSC-1 overexpression reduced the metastasis ability of MDA-MB-231 cells in vitro. Further research confirmed that the BCSC-1 overexpression reduced the expression levels of MMP7, MMP9 and OPN, and the phosphorylation of NF-κB p65. Furthermore, inhibition of BCSC-1 via lentivirus-mediated RNA interference revealed that the downregulation of BCSC-1 increased the invasive ability of MCF-7 cells. In summary, the results demonstrated that BCSC-1 is expressed at low levels in breast cancer tissues, and that it can suppress human breast cancer cell migration and invasion, potentially altering the expression of MMP7, MMP9, OPN, and the activity of the NF-κB pathway. Therefore, BCSC-1 may be useful as a biomarker for the treatment of breast cancer in the future.

Recent evidence suggests that numerous long non‑coding RNAs (lncRNAs) are dysregulated in cancer, and have critical roles in tumour development and progression. The present study investigated the ghrelin receptor antisense lncRNA growth hormone secretagogue receptor opposite strand (GHSROS) in breast cancer. Reverse transcription‑quantitative polymerase chain reaction revealed that GHSROS expression was significantly upregulated in breast tumour tissues compared with normal breast tissue. Induced overexpression of GHSROS in the MDA‑MB‑231 breast cancer cell line significantly increased cell migration in vitro, without affecting cell proliferation, a finding similar to our previous study on lung cancer cell lines. Microarray analysis revealed a significant repression of a small cluster of major histocompatibility class II genes and enrichment of immune response pathways; this phenomenon may allow tumour cells to better evade the immune system. Ectopic overexpression of GHSROS in the MDA‑MB‑231 cell line significantly increased orthotopic xenograft growth in mice, suggesting that in vitro culture does not fully capture the function of this lncRNA. This study demonstrated that GHSROS may serve a relevant role in breast cancer. Further studies are warranted to explore the function and therapeutic potential of this lncRNA in breast cancer progression.

HDAC inhibitors (HDACis) represent a class of anticancer agents including suberoylanilide hydroxamic acid (SAHA, Vorinostat), which has shown a strong antitumor effect, both in vitro and in vivo. Induction of apoptotic genes is an important pathway of SAHA cytotoxic mechanism of action and it has been largely described that SAHA induces sensitization of cell death receptor-resistant breast cancer cells to apoptosis. In this study, we investigated the activation of some apoptotic genes which could be responsible for the in vivo antitumor potency of SAHA in a model of human breast cancer. We found that the apoptotic gene pattern induced by SAHA in the MDA-MB-231 cell line involves the upregulation of some molecules belonging to the TNF superfamily. In particular, we demonstrated that the upregulation of the CD137 receptor/ligand system correlates with a synergistic cytotoxic effect when MDA-MB-231 cells are treated with the combination of SAHA and soluble CD137 receptor. To our knowledge, this is the first study to indicate that this member of the TNF superfamily, CD137, is modulated by SAHA treatment in breast cancer cells, suggesting that the combination of SAHA with this TNF-related receptor could be a new therapeutic approach for the treatment of tumors.

We evaluated in vitro the potentiating and/or synergistic antitumor effects among retinoids (all-trans-retinoic acid, tRA, and 13-cis-retinoic acid, 13cRA), alpha-interferon 2a (alpha-IFN 2a) and tamoxifen (TAM) on both estrogen receptor positive (ER(+)) and negative (ER(-)) human breast cancer cell lines. In our experimental model, the three studied agents showed antiproliferative activity in ER(+) cell lines MCF-7 and ZR-75.1, while alpha-IFN 2a was the most effective drug in the ER(-) cell line MDA-MB-231. Retinoids and TAM exerted a strong apoptotic effect in MCF-7 cells, while such an effect was obtained in MDA-MB-231 cells by alpha-IFN 2a. The tested combinations displayed different effects in the different evaluated cell lines: i) in MCF-7 cells tRA + TAM showed additive activity, both tRA + alpha-IFN 2a and TAM + alpha-IFN 2a association displayed a synergistic effect, and a further potentiation of the antiproliferative action was detected with the triple combination; ii) in ZR-75.1 cell line an additive activity was showed by tRA + TAM and TAM + alpha-IFN 2a, while tRA + alpha-IFN 2a produced synergistic action; iii) in MDA-MB-231 cell line only alpha-IFN 2a displayed a strong antiproliferative effect, and no significant potentiation was exerted by any drug association. The feasibility and activity of such combinations have been tested in two pilot clinical trials on patients with metastatic breast cancer: both the tested associations were tolerable, with good treatment compliance and low toxicity. The different antiproliferative and apoptotic effects observed in vitro on apparently similar breast cancer cell lines prompted us to a further investigation of the mutual biological modulations of these drug combinations, in view of a better selection of patients who might potentially benefit from these treatments.

There is a growing body of evidence indicating that calcitonin (CT) and calcitonin receptor (CTR) are involved in the regulation of cell growth, differentiation, and survival and in tissue development. However, the precise functional role of CT/CTR in breast cancer is still unknown. It is well established that the urokinase plasminogen activator (uPA) system plays an important role in breast cancer invasion and metastasis. The goal of this study was to investigate the effects of CT on regulation of the uPA system and invasive capacity of breast cancer cells. In the highly invasive MDA-MB-231 cell line, 10(-8) M CT decreased both uPA and uPAR mRNA and protein expression which was associated with inhibition of the extracellular signal-regulated kinase (ERK) 1/2 pathway. Furthermore, two weeks of CT administration to nude mice inhibited the expression of uPA mRNA in primary tumors by 25% (P

Stromal cell-derived factor-1 (SDF-1), via its receptor CXCR4, has been implicated in metastasis of cancer, including breast cancer. Exogenous SDF-1 is known to regulate locomotion, chemotaxis and adhesion. The knowledge regarding the effect of autocrine SDF-1 on breast cancer cells is not available. The current study evaluated the effects of SDF-1 on the biological behaviour of breast cancer cells by genetically modifying the expression of SDF-1 in breast cancer cells. Two human breast cancer cell lines (MDA-MB-231 and MDA-MB-435s) and a human fetal lung fibroblast cell line (MRC5) were used. The expression of SDF-1 and the SDF-1 receptor, CXCR4 in the cell lines were studied. Expression cassettes of human SDF-1 and hammerhead ribozyme transgenes specifically targeting human SDF-1 were constructed and used to over-express SDF-1 or to knockout the expression of SDF-1 in cancer cells, respectively. Invasiveness, migration and growth of the genetically modified cells were assessed. SDF-1 was expressed in wild-type human breast cancer cell line MDA-MB-435s and fibroblast cell line MRC5, but not in MDA-MB-231 cell line. In contrast, CXCR4 expression was observed in all three cell lines tested. The ability of invasion and migration was significantly reduced in SDF-1 knockout MDA-MB-435s cells, compared with wild-type and vector control cells (p

Progression of breast cancer implicates the degradation of extracellular matrix (ECM) by metalloproteinases (MMPs), a process with important consequences on the growth and invasiveness of cancer cells in adjacent and distant sites. The isoflavone, genistein - a natural inhibitor of protein tyrosine kinase pathway - inhibits the growth of a wide range of cancer cells in vitro. The aim of this study was to investigate: i) the expression of mRNAs encoded for MMPs and their endogenous inhibitors (TIMPs) associated with pathogenesis and metastatic potential of breast cancer cells; and ii) the effect of genistein on the transcription of MMPs and TIMPs and the invasive potential of breast cancer cells. Gene expression at transcriptional level was examined in cell cultures of two epithelial breast cancer cell lines, the high invasive (ER-negative) MDA-MB-231 and the low invasive (ER-positive) MCF-7, as well as the normal mammary cells (MCF-12A) following RNA isolation and reversed transcriptase polymerase chain reaction (RT-PCR). The inhibitory effect of genistein on functional invasiveness was examined by a cell invasion assay. Cell cycle distribution showed that genistein arrested breast cancer MDA-MB-231, MCF-7 and BT-20 cells in the G 2 /M phase. Both normal and breast cancer cell lines express the genes of MMP-2, -9, MT1-, MT2-, MT3-MMP and TIMP-1, -2 and -3. MCF-7 express notably less MMPs than MDA-MB-231 cell line. The addition of genistein resulted in down-regulation of the transcription of all MMP genes in MDA-MB-231 and most of MMPs in MCF-7 cells. The inhibitory effect of genistein on MMPs was functionally confirmed, since it significantly reduced the invasion properties of cancer cells in vitro. The obtained results indicate that genistein may be of great value in prevention of breast cancer cell metastasis, since it represents both a transcriptional modulator of genes involved in this pathogenetic process and a suppressor of breast cancer cell invasiveness.

High level expression of urokinase plasminogen activator (uPA) has been well documented in a variety of tumors. In breast cancer, expression of uPA is essential for tumor cell invasion, metastasis and proliferation. By contrast, the primary objective of tumor therapy is to reduce the uPA expression level within the tumor, which results in abrogation of proliferation, invasion and metastasizing of the tumor cells. We investigated the effects of uPA on the MDA-MB-231 cell line. MDA-MB-231 cells are highly invasive and express high levels of uPA. In our study, uPA inhibition was achieved by two methodologies: a) stable transfection with an antisense uPA vector, b) transfection with siRNA molecules (small interfering RNA). A plasmid vector was constructed by cloning a uPA-specific cDNA (612 bp) fragment into pBK-CMV plasmid in antisense orientation. In contrast, a double-stranded 21-mer siRNA was designed for targeting uPA. The antisense-transfected cells revealed decreased uPA mRNA and protein as detected by real-time PCR, immunocytochemistry, ELISA, and Western blotting. Moreover, the transfected cells exhibited a significantly reduced proliferation activity as determined by a fluorometric proliferation assay. As a conclusion of our study siRNA-technique is the superior method also regarding time saving for clone selection and instant availability of the transfected cells. Moreover, even if both strategies lead to uPA suppression, a stronger inhibitory effect could be obtained by application of the siRNA-based technique.

Bone metastases are generally associated with bone destruction which occurs in response to factors secreted by metastatic cells. Some of these factors secreted by the metastatic cells activate osteoclats while others are proteases that degrade bone collagen. To determine if Neovastat (AE-941), a naturally occurring multi-functional inhibitor of angiogenesis, is able to regulate properties that are thought to have relevance to their propensity to form bone metastases in vivo, we used the human breast cancer MDA-MB-231 cell line which can metastasize to bone. We showed that Neovastat prevented the degradation of osteoid-like radiolabeled extracellular matrices which was induced by incubation of human SaOS-2 osteoblast-like cells with MDA-MB-231 cells. Moreover, Neovastat was demonstrated to inhibit the gelatinolytic activity of matrix metalloproteinase (MMP)-9 expressed by MDA-MB-231 cells. The potential of Neovastat to retard the spread, growth, and osteolysis of MDA-MB-231 cells was then estimated in vivo. Histomorphometric analysis of the vertebral bodies indicated that MDA-MB-231 cells inoculated in nude mice (intracardiac) successfully generate osteolytic metastases with an 83% reduction of the volume of medullary bone (p< or =0.01). However, when tumor-bearing animals were treated orally with Neovastat, there was only a 19% decrease in medullary bone thus indicating that Neovastat can prevent bone metastasis in this model. Consistent with histological results, radiographic analysis indicated that Neovastat decreased the number of osteolytic lesions by 33% (p< or =0.3). Moreover, a decrease in the tumor volume in bone was observed in Neovastat-treated animals. These results indicate that Neovastat may be useful in preventing bone metastasis in cancer patients.

Bone metastases are generally associated with bone destruction which occurs in response to factors secreted by metastatic cells. Some of these factors secreted by the metastatic cells activate osteoclats while others are proteases that degrade bone collagen. To determine if Neovastat (AE-941), a naturally occurring multi-functional inhibitor of angiogenesis, is able to regulate properties that are thought to have relevance to their propensity to form bone metastases in vivo, we used the human breast cancer MDA-MB-231 cell line which can metastasize to bone. We showed that Neovastat prevented the degradation of osteoid-like radiolabeled extracellular matrices which was induced by incubation of human SaOS-2 osteoblast-like cells with MDA-MB-231 cells. Moreover, Neovastat was demonstrated to inhibit the gelatinolytic activity of matrix metalloproteinase (MMP)-9 expressed by MDA-MB-231 cells. The potential of Neovastat to retard the spread, growth, and osteolysis of MDA-MB-231 cells was then estimated in vivo. Histomorphometric analysis of the vertebral bodies indicated that MDA-MB-231 cells inoculated in nude mice (intracardiac) successfully generate osteolytic metastases with an 83% reduction of the volume of medullary bone (por =0.01). However, when tumor-bearing animals were treated orally with Neovastat, there was only a 19% decrease in medullary bone thus indicating that Neovastat can prevent bone metastasis in this model. Consistent with histological results, radiographic analysis indicated that Neovastat decreased the number of osteolytic lesions by 33% (por =0.3). Moreover, a decrease in the tumor volume in bone was observed in Neovastat-treated animals. These results indicate that Neovastat may be useful in preventing bone metastasis in cancer patients.

Microsatellite mutation of the polyadenine tract (10 adenine repeat) within the TbetaR-II [transforming growth factor-beta (TGF-beta) receptor type II] coding region have been found in a variety of human cancers, particularly in association with microsatellite instability (MSI). Since breast cancers have been reported to carry MSI, although its frequencies were quite variable, we examined whether microsatellite mutation of the polyadenine tract occurs in the human breast cancer MDA-MB-231 cell line. TbetaR-II expression in MDA-MB-231 was found to be low on our Northern and Western analyses. Sequencing analysis for the polyadenine tract of TbetaR-II cDNA obtained from MDA-MB-231 cells indicated heterozygous deletion of one adenine base. Subsequently, sensitivity to TGF-beta induced growth-inhibitory effects of control and TbetaR-II transfected MDA-MB-231 cells was compared. The sensitivity of TbetaR-II transfectants to exogenous as well as endogenous TGF-beta1 was increased distinctly compared with control transfectant. These results suggest that heterozygous deletion of one adenine base within the polyadenine tract in MDA-MB-231 cells might lead to reduced TbetaR-II expression and sensitivity to TGF-beta.