Risk factors and prognosis of early neurological deterioration in patients with posterior circulation cerebral infarction.

BACKGROUND: The incidence, risk factors, and pathogenesis of early neurological deterioration (END) in posterior circulation stroke are still unclear. In this study, we aimed to determine the risk factors and prognosis of END in patients with acute posterior circulation cerebral infarction. METHODS: Acute posterior circulation ischemic stroke patients who had completed neuroimaging within 72 h of onset were selected from a prospective registry study Demographic characteristics, physiological data, medical history, laboratory data, in-hospital evaluation, neurological severity and TOAST classification, treatment, and the modified Rankin Scale (mRS) score of patients were assessed. Early neurological deterioration was defined as an increase of 2 points in the National Institutes of Health Stroke Scale score between the baseline and 72 h evaluation. Favorable and poor outcomes were defined as mRSs of 02 and≥ 3, respectively, at 3 months. The incidence and risk factors were evaluated by univariate and multivariate regression analysis (step-back method). RESULTS: The analysis included 455 subjects with an acute posterior circulation non-cardiac ischemic stroke, 330 (72.53 %) of them male, with an average age of 63.12 ( ± 10.14) years and with 47 (10.33 %) having END. The results of univariate and multivariate logistic regression analysis showed that BATMAN scores ≥ 5 (OR: 0.1, 95 % CI: 0.02-0.53, P < 0.01), large artery atherosclerosis (OR: 11.55, 95 % CI: 4.18-31.93, P < 0.01), vascular stenosis > 50 % (OR: 2.44, 95 % CI: 1.1-5.42, P = 0.029), reperfusion therapy (OR: 4.21, 95 % CI: 1.66-10.64, P < 0.01), and the distribution of pontine lesions (OR: 5.66, 95 % CI: 2.39-13.44, P < 0.01) were significantly associated with END. Patients with END had a lower rate of favorable outcomes at discharge and long-term follow-up (P < 0.001), regardless of whether they received reperfusion therapy. CONCLUSION: The lesion distribution of the pons, the progression of temporo-occipital lobe lesions, and large arterial atherosclerosis are independent risk factors of END that might predict a poor short- and long-term prognosis.

LRRC75A-AS1 delivered by M2 macrophage exosomes promotes cervical cancer progression via enhancing SIX1 expression.

We aimed to investigate potential roles of LRRC75A-AS1 delivered by M2 macrophage exosomes in inducing cervical cancer progression. We demonstrated LRRC75A-AS1 was highly expressed in exosomes from M2 macrophages which could be absorbed by Hela cells. M2 macrophage-derived exosomes promoted Hela cell proliferation, migration, invasion, and EMT process by delivering LRRC75A-AS1. LRRC75A-AS1 directly targeted and suppressed miR-429 in Hela cells. The regulation of cell functions by exosomes from LRRC75A-AS1-overexpressing M2 macrophages was abrogated by miR-429 mimics. miR-429 directly targeted and repressed SIX1 expression. SIX1 overexpression alleviated the modulation of cellular functions and STAT3/MMP-9 signaling by miR-429 mimics. Also, miR-429 overexpression or SIX1 silence repressed tumor formation and metastasis in nude mice, which was mitigated by exosomes from LRRC75A-AS1-overexpressing M2 macrophages. In conclusion, LRRC75A-AS1 delivered by M2 macrophage exosomes repressed miR-429 to elevate SIX1 expression and promote cervical cancer progression through activating the STAT3/MMP-9 axis.

Synergistic Effect of Quercetin on Antibacterial Activity of Florfenicol Against Aeromonas hydrophila In Vitro and In Vivo.

The overuse or abuse of antimicrobial drugs in aquaculture, aggravates the generation of drug-resistant bacteria, which has caused potential risks to human health and the aquaculture industry. Flavonoid-antibiotic combinations have been shown to suppress the emergence of resistance in bacteria, and sometimes even reverse it. Here, the antibacterial activity of florfenicol in combination with quercetin, a potential drug to reverse multidrug resistance, was tested against Aeromonas hydrophila (A. hydrophila). Of eleven selected antimicrobial agents, quercetin and florfenicol showed the strongest bactericidal effect, and fractional inhibitory concentration (FIC) indices were 0.28, showing a highly synergistic effect. Then, the antibacterial activities of quercetin and florfenicol against A. hydrophila were further tested in vitro and in vivo. Bacterial viability of A. hydrophila decreased in a florfenicol dose-dependent manner, about 16.3-191.4-fold lower in the presence of 15 µg/mL quercetin and 0.156 to 1.25 µg/mL florfenicol than in the absence of quercetin, respectively. The cell killing was maximum at 45 µg/mL quercetin in the dose range tested plus 0.156 µg/mL florfenicol. The viability decreased over time during the combined treatment with quercetin and florfenicol by 60.5- and 115-fold in 0.156 µg/mL florfenicol and 0.625 µg/mL florfenicol, respectively. Additionally, the synergistic effect was confirmed by the bacterial growth curve. Furthermore, quercetin and florfenicol had an obvious synergistic activity in vivo, reducing the bacterial load in the liver, spleen and kidney tissues of Cyprinus carpio up to 610.6-fold compared with the florfenicol group, and improving the survival rate of infected fish from 10% in the control group to 90% in drug combinations group. These findings indicated that quercetin could potentiate the antibacterial activity of florfenicol against A. hydrophila infection and may reduce the use of antimicrobial drugs and improve the prevention and control capability of bacterial resistance.

Postoperative hyperglycemia predicts symptomatic intracranial hemorrhage after endovascular treatment in patients with acute anterior circulation large artery occlusion.

INTRODUCTION: Acute phase hyperglycemia is independently associated with an increased risk of death and symptomatic intracranial hemorrhage (sICH) in stroke patients treated with intravenous thrombolysis. Whether postoperative hyperglycemia is an independent predictor of sICH after endovascular therapy remains unknown. Here, we assessed whether hyperglycemia after endovascular therapy can predict sICH. METHODS: Consecutive acute ischemic stroke patients who were treated with mechanical thrombectomy with or without subsequent stent implantation were analyzed. The primary outcome was the occurrence of sICH within the first 7 days after endovascular treatment. The second outcome was other forms of hemorrhagic transformation (HT), including parenchymal hematoma (PH) and parenchymal hematoma type 2 (PH-2). RESULTS: One hundred and fifty-six patients were included. Fifteen patients (9.62%) developed sICH after endovascular therapy. After adjusting for potential confounding factors, postoperative glucose values were independently associated with sICH after endovascular therapy. Furthermore, adding postoperative glucose values to conventional risk factors led to a substantial reclassification for sICH following endovascular therapy (net reclassification improvement = 28.1%; p = .014). Moreover, postoperative glucose values were found to be risk factors for PH-2. CONCLUSIONS: We found that postoperative glucose values might be an independent risk factor for sICH in patients with anterior circulation large vessel occlusion who are treated with mechanical thrombectomy. Adding postoperative glucose values to conventional risk factors could improve risk stratification for sICH following endovascular therapy.

LncRNA NKILA suppresses TGF-ß-induced epithelial-mesenchymal transition by blocking NF-κB signaling in breast cancer.

TGF-ß plays a central role in mediating epithelial-mesenchymal transition (EMT) by activating the Smad pathway. In addition, accumulating evidence suggests that TGF-ß-induced EMT is NF-κB-dependent in various cancer types. However, it is largely unclear if NF-κB mediates TGF-ß-induced EMT in breast cancer, and if this mediation occurs, the regulatory mechanisms are unknown. In our study, we found that TGF-ß activates the NF-κB pathway. Inhibition of NF-κB signaling markedly abrogates TGF-ß-induced EMT. By studying the regulatory mechanism of TGF-ß-induced NF-κB signaling, we found that lncRNA NKILA was upregulated by TGF-ß and was essential for the negative feedback regulation of the NF-κB pathway. Accordingly, overexpression of NKILA significantly reduced TGF-ß-induced tumor metastasis in vivo. Consistent with the results from mice, the expression of NKILA was negatively correlated with EMT phenotypes in clinical breast cancer samples. Collectively, our study indicated that the NKILA-mediated negative feedback affects TGF-ß-induced NF-κB activation and that NKILA may be a therapeutic molecule in breast cancer metastasis via inhibition of EMT.

Epstein-Barr Virus-Induced VEGF and GM-CSF Drive Nasopharyngeal Carcinoma Metastasis via Recruitment and Activation of Macrophages.

Chronic inflammation induced by persistent microbial infection plays an essential role in tumor progression. Although it is well documented that Epstein-Barr virus (EBV) infection is closely associated with nasopharyngeal carcinoma (NPC), how EBV-induced inflammation promotes NPC progression remains largely unknown. Here, we report that tumor infiltration of tumor-associated macrophages (TAM) and expression of CCL18, the cytokine preferentially secreted by TAM, closely correlate with serum EBV infection titers and tumor progression in two cohorts of NPC patients. In vitro, compared with EBV- NPC cell lines, EBV+ NPC cell lines exhibited superior capacity to attract monocytes and skew them to differentiate to a TAM-like phenotype. Cytokine profiling analysis revealed that NPC cells with active EBV replications recruited monocytes by VEGF and induced TAM by GM-CSF in an NF-κB-dependent manner. Reciprocally, TAM induced epithelial-mesenchymal transition and furthered NF-κB activation of tumor cells by CCL18. In humanized mice, NPC cells with active EBV replications exhibited increased metastasis, and neutralization of CCL18, GM-CSF, and VEGF significantly reduced metastasis. Collectively, our work defines a feed-forward loop between tumor cells and macrophages in NPC, which shows how metastatic potential can evolve concurrently with virus-induced chronic inflammation. Cancer Res; 77(13); 3591-604. ©2017 AACR.

Blocking the recruitment of naive CD4+ T cells reverses immunosuppression in breast cancer.

The origin of tumor-infiltrating Tregs, critical mediators of tumor immunosuppression, is unclear. Here, we show that tumor-infiltrating naive CD4+ T cells and Tregs in human breast cancer have overlapping TCR repertoires, while hardly overlap with circulating Tregs, suggesting that intratumoral Tregs mainly develop from naive T cells in situ rather than from recruited Tregs. Furthermore, the abundance of naive CD4+ T cells and Tregs is closely correlated, both indicating poor prognosis for breast cancer patients. Naive CD4+ T cells adhere to tumor slices in proportion to the abundance of CCL18-producing macrophages. Moreover, adoptively transferred human naive CD4+ T cells infiltrate human breast cancer orthotopic xenografts in a CCL18-dependent manner. In human breast cancer xenografts in humanized mice, blocking the recruitment of naive CD4+ T cells into tumor by knocking down the expression of PITPNM3, a CCL18 receptor, significantly reduces intratumoral Tregs and inhibits tumor progression. These findings suggest that breast tumor-infiltrating Tregs arise from chemotaxis of circulating naive CD4+ T cells that differentiate into Tregs in situ. Inhibiting naive CD4+ T cell recruitment into tumors by interfering with PITPNM3 recognition of CCL18 may be an attractive strategy for anticancer immunotherapy.

Long non-coding RNA NKILA inhibits migration and invasion of tongue squamous cell carcinoma cells via suppressing epithelial-mesenchymal transition.

Long non-coding RNAs (lncRNAs) have emerged recently as key regulators of tumor development and progression. Our previous study identified an NF-KappaB interacting lncRNA (NKILA) which was negatively correlated with breast cancer metastasis and patient prognosis. However, its clinical significance and potential role in Tongue squamous cell carcinoma (TSCC) remain unclear. Here we show that NKILA is down-regulated in TSCC cancer tissues than that in matched adjacent noncancerous tissues. And low NKILA expression in TSCC is significantly correlated with tumor metastasis and poor patient prognosis. In vitro, overexpression of NKILA decreases TSCC cells migration and invasion. Mechanistic study shows that NKILA inhibits the phosphorylation of IκBα and NF-κB activation as well as the induction of the epithelial-mesenchymal transition (EMT) process. Ectopic expression of NKILA in Tscca cells inhibits NF-κB activator TNF-α-promoted cell migration and invasion, while applying NF-κB inhibitor Bay-117082 or JSH-23 in NKILA silenced CAL27 cells reverses cell migration capacity to lower level. In vivo experimental metastasis model also demonstrates NKILA inhibits lung metastasis of NOD/SCID mice with TSCC tumors. These results suggested that NKILA is a vital determinant of TSCC migration and invasion and NF-κB signaling pathway mediates this effect. Given the above mentioned function of NKILA, it could act as a potential predictor for overall survival in patients with TSCC and a potential therapeutic target for TSCC intervention.

miR-142-5p and miR-130a-3p are regulated by IL-4 and IL-13 and control profibrogenic macrophage program.

Macrophages play a pivotal role in tissue fibrogenesis, which underlies the pathogenesis of many end-stage chronic inflammatory diseases. MicroRNAs are key regulators of immune cell functions, but their roles in macrophage's fibrogenesis have not been characterized. Here we show that IL-4 and IL-13 induce miR-142-5p and downregulate miR-130a-3p in macrophages; these changes sustain the profibrogenic effect of macrophages. In vitro, miR-142-5p mimic prolongs STAT6 phosphorylation by targeting its negative regulator, SOCS1. Blocking miR-130a relieves its inhibition of PPARγ, which coordinates STAT6 signalling. In vivo, inhibiting miR-142-5p and increasing miR-130a-3p expression with locked nucleic acid-modified oligonucleotides inhibits CCL4-induced liver fibrosis and bleomycin-induced lung fibrosis in mice. Furthermore, macrophages from the tissue samples of patients with liver cirrhosis and idiopathic pulmonary fibrosis display increased miR-142-5p and decreased miR-130a-3p expression. Therefore, miR-142-5p and miR-130a-3p regulate macrophage profibrogenic gene expression in chronic inflammation.

Regulation of SOX10 stability via ubiquitination-mediated degradation by Fbxw7α modulates melanoma cell migration.

Dysregulation of SOX10 was reported to be correlated with the progression of multiple cancer types, including melanocytic tumors and tumors of the nervous system. However, the mechanisms by which SOX10 is dysregulated in these tumors are poorly understood. In this study, we report that SOX10 is a direct substrate of Fbxw7α E3 ubiquitin ligase, a tumor suppressor in multiple cancers. Fbxw7α promotes SOX10 ubiquitination-mediated turnover through CPD domain of SOX10. Besides, GSK3ß phosphorylates SOX10 at CPD domain and facilitates Fbxw7α-mediated SOX10 degradation. Moreover, SOX10 protein levels were inversely correlated with Fbxw7α in melanoma cells, and modulation of Fbxw7α levels regulated the expression of SOX10 and its downstream gene MIA. More importantly, SOX10 reversed Fbxw7α-mediated suppression of melanoma cell migration. This study provides evidence that the tumor suppressor Fbxw7α is the E3 ubiquitin ligase responsible for the degradation of SOX10, and suggests that reduced Fbxw7α might contribute to the upregulation of SOX10 in melanoma cells.

CCL18-mediated down-regulation of miR98 and miR27b promotes breast cancer metastasis.

Our previous work has indicated that CCL18 secreted by tumor-associated macrophages (TAMs) promotes breast cancer metastasis, which is associated with poor patient prognosis. However, it remains unclear whether microRNAs (miRNAs), which may modulate multiple cellular pathways, are involved in the regulation of CCL18 signaling and the ensuing metastasis of breast cancer. In this study, we demonstrated that CCL18 reduces miR98 and miR27b expression via the N-Ras/ERK/PI3K/NFκB/Lin28b signaling pathway, while down-regulation of these mRNAs feedbacks to increase N-Ras and Lin28b levels. This cascade of events forms a positive feedback loop that sustains the activation of CCL18 signaling. More importantly, reduction in miR98 and miR27b enhances the epithelial-mesenchymal transition (EMT) of breast cancer cells, and thus promotes breast cancer metastasis. These findings suggest that down-regulation of miR98 and miR27b promotes CCL18-mediated invasion and migration of breast cancer cells.

Nerve fibers in breast cancer tissues indicate aggressive tumor progression.

Emerging evidence has indicated nerve fibers as a marker in the progression of various types of cancers, such as pancreatic cancer and prostate cancer. However, whether nerve fibers are associated with breast cancer progression remains unclear. In this study, we evaluated the presence of nerve fibers in 352 breast cancer specimens and 83 benign breast tissue specimens including 43 cases of cystic fibrosis and 40 cases of fibroadenoma from 2 independent breast tumor center using immunohistochemical staining for specific peripheral nerve fiber markers.In all, nerve fibers were present in 130 out of 352 breast cancer tissue specimens, while none were detected in normal breast tissue specimens. Among 352 cases, we defined 239 cases from Sun Yat-Sen Memorial Hospital, Guangzhou, China, as the training set, and 113 cases from the First Affiliated Hospital of Shantou University, Guangdong, China, as the validation set. The thickness of tumor-involving nerve fibers is significantly correlated with poor differentiation, lymph node metastasis, high clinical staging, and triple negative subtype in breast cancer. More importantly, Cox multifactor analysis indicates that the thickness of tumor-involving nerve fibers is a previously unappreciated independent prognostic factors associated with shorter disease-free survival of breast cancer patients. Our findings are further validated by online Oncomine database. In conclusion, our results show that nerve fiber involvement in breast cancer is associated with progression of the malignancy and warrant further studies in the future.

miR-21 induces myofibroblast differentiation and promotes the malignant progression of breast phyllodes tumors.

Phyllodes tumors of breast, even histologically diagnosed as benign, can recur locally and have metastatic potential. Histologic markers only have limited value in predicting the clinical behavior of phyllodes tumors. It remains unknown what drives the malignant progression of phyllodes tumors. We found that the expression of myofibroblast markers, α-smooth muscle actin (α-SMA), fibroblast activation protein (FAP), and stromal cell-derived factor-1 (SDF-1), is progressively increased in the malignant progression of phyllodes tumors. Microarray showed that miR-21 was one of the most significantly upregulated microRNAs in malignant phyllodes tumors compared with benign phyllodes tumors. In addition, increased miR-21 expression was primarily localized to α-SMA-positive myofibroblasts. More importantly, α-SMA and miR-21 are independent predictors of recurrence and metastasis, with their predictive value of recurrence better than histologic grading. Furthermore, miR-21 mimics promoted, whereas miR-21 antisense oligos inhibited, the expression of α-SMA, FAP, and SDF-1, as well as the proliferation and invasion of primary stromal cells of phyllodes tumors. The ability of miR-21 to induce myofibroblast differentiation was mediated by its regulation on Smad7 and PTEN, which regulate the migration and proliferation, respectively. In breast phyllodes tumor xenografts, miR-21 accelerated tumor growth, induced myofibroblast differentiation, and promoted metastasis. This study suggests an important role of myofibroblast differentiation in the malignant progression of phyllodes tumors that is driven by increased miR-21.

A positive feedback loop between mesenchymal-like cancer cells and macrophages is essential to breast cancer metastasis.

The close vicinity of cancer cells undergoing epithelial-mesenchymal transition (EMT) and tumor-associated macrophages (TAMs) at the invasive front of tumors suggests that these two cell type may mutually interact. We show that mesenchymal-like breast cancer cells activate macrophages to a TAM-like phenotype by GM-CSF. Reciprocally, CCL18 from TAMs induces cancer cell EMT, forming a positive feedback loop, in coculture systems and humanized mice. Inhibition of GM-CSF or CCL18 breaks this loop and reduces cancer metastasis. High GM-CSF expression in breast cancer samples is associated with more CCL18(+) macrophages, cancer cell EMT, enhanced metastasis, and reduced patient survival. These findings suggest that a positive feedback loop between GM-CSF and CCL18 is important in breast cancer metastasis.

Pyk2 and Src mediate signaling to CCL18-induced breast cancer metastasis.

Pyk2 and Src phosphorylation is initiated by CCL18, which promotes breast cancer metastasis via its functional G protein-coupled receptor PITPNM3. However, the function of Pyk2 and Src in CCL18-induced breast cancer metastasis is poorly understood. Quantitative reverse-transcription polymerase chain reactions (qRT-PCRs), Western blot, boyden chamber assay, and adherence assay were performed to delineate the consequences of Pyk2/Src in CCL18-induced breast cancer cells. Co-immunoprecipitation and immunofluorescence were performed to analyze the interaction of proteins. Upon the binding of CCL18 to PITPNM3, Pyk2 translocates from the cytoplasm to the plasma membrane to form a stable complex with PITPNM3, subsequently activating Src kinase. Moreover, upon stimulation with CCL18, Pyk2 and Src become essential for integrin alpha5/beta1 clustering-dependent adherence, migration, and invasion. Pyk2 and Src are important in CCL18-induced breast cancer metastasis.

Lin28 induces epithelial-to-mesenchymal transition and stemness via downregulation of let-7a in breast cancer cells.

The RNA-binding protein Lin28 is known to promote malignancy by inhibiting the biogenesis of let-7, which functions as a tumor suppressor. However, the role of the Lin28/let-7 axis in the epithelial-to-mesenchymal transition (EMT) and stemness in breast cancer has not been clearly expatiated. In our previous study, we demonstrated that let-7 regulates self-renewal and tumorigenicity of breast cancer stem cells. In the present study, we demonstrated that Lin28 was highly expressed in mesenchymal (M) type cells (MDA-MB-231 and SK-3rd), but it was barely detectable in epithelial (E) type cells (MCF-7 and BT-474). Lin28 remarkably induced the EMT, increased a higher mammosphere formation rate and ALDH activity and subsequently promoted colony formation, as well as adhesion and migration in breast cancer cells. Furthermore, we demonstrated that Lin28 induced EMT in breast cancer cells via downregulation of let-7a. Strikingly, Lin28 overexpression was found in breast cancers that had undergone metastasis and was strongly predictive of poor prognoses in breast cancers. Given that Lin28 induced the EMT via let-7a and promoted breast cancer metastasis, Lin28 may be a therapeutic target for the eradication of breast cancer metastasis.

The overexpression of hypomethylated miR-663 induces chemotherapy resistance in human breast cancer cells by targeting heparin sulfate proteoglycan 2 (HSPG2).

MicroRNAs are involved in regulating the biology of cancer cells, but their involvement in chemoresistance is not fully understood. We found that miR-663 was up-regulated in our induced multidrug-resistant MDA-MB-231/ADM cell line and that this up-regulation was closely related to chemosensitivity. In the present study, we aimed to clarify the role of miR-663 in regulating the chemoresistance of breast cancer. MicroRNA microarray and quantitative RT-PCR assays were used to identify differentially expressed microRNAs. Cell apoptosis was evaluated by annexin V/propidium iodide staining, TUNEL, and reactive oxygen species generation analysis. The expression of miR-663 and HSPG2 in breast cancer tissues was detected by in situ hybridization and immunohistochemistry. The potential targets of miR-663 were defined by a luciferase reporter assay. Bisulfite sequencing PCR was used to analyze the methylation status. We found that miR-663 was significantly elevated in MDA-MB-231/ADM cells, and the down-regulation of miR-663 sensitized MDA-MB-231/ADM cells to both cyclophosphamide and docetaxel. The overexpression of miR-663 in breast tumor tissues was associated with chemoresistance; in MDA-MB-231 cells, this chemoresistance was accompanied by the down-regulation of HSPG2, which was identified as a target of miR-663. MDA-MB-231/ADM contained fewer methylated CpG sites than its parental cell line, and miR-663 expression in MDA-MB-231 cells was reactivated by 5-aza-29-deoxycytidine treatment, indicating that DNA methylation may play a functional role in the expression of miR-663. Our findings suggest that the overexpression of hypomethylated miR-663 induced chemoresistance in breast cancer cells by down-regulating HSPG2, thus providing a potential target for the development of an microRNA-based approach for breast cancer therapy.

MicroRNA 34c gene down-regulation via DNA methylation promotes self-renewal and epithelial-mesenchymal transition in breast tumor-initiating cells.

Tumor-initiating cells (T-ICs), a subpopulation of cancer cells with stem cell-like properties, are related to tumor relapse and metastasis. Our previous studies identified a distinct profile of microRNA (miRNA) expression in breast T-ICs (BT-ICs), and the dysregulated miRNAs contribute to the self-renewal and tumorigenesis of these cells. However, the underlying mechanisms for miRNA dysregulation in BT-ICs remain obscure. In the present study, we demonstrated that the expression and function of miR-34c were reduced in the BT-ICs of MCF-7 and SK-3rd cells, a breast cancer cell line enriched for BT-ICs. Ectopic expression of miR-34c reduced the self-renewal of BT-ICs, inhibited epithelial-mesenchymal transition, and suppressed migration of the tumor cells via silencing target gene Notch4. Furthermore, we identified a single hypermethylated CpG site in the promoter region of miR-34c gene that contributed to transcriptional repression of miR-34c in BT-ICs by reducing DNA binding activities of Sp1. Therefore, miR-34c reduction in BT-ICs induced by a single hypermethylated CpG site in the promoter region promotes self-renewal and epithelial-mesenchymal transition of BT-ICs.

miR-124 suppresses multiple steps of breast cancer metastasis by targeting a cohort of pro-metastatic genes in vitro.

Metastasis is a multistep process involving modification of morphology to suit migration, reduction of tumor cell adhesion to the extracellular matrix, increase of cell mobility, tumor cell resistance to anoikis, and other steps. MicroRNAs are well-suited to regulate tumor metastasis due to their capacity to repress numerous target genes in a coordinated manner, thereby enabling their intervention at multiple steps of the invasion-metastasis cascade. In this study, we identified a microRNA exemplifying these attributes, miR-124, whose expression was reduced in aggressive MDA-MB-231 and SK-3rd breast cancer cells. Down-regulation of miR-124 expression in highly aggressive breast cancer cells contributed in part to DNA hypermethylation around the promoters of the three genes encoding miR-124. Ectopic expression of miR-124 in MDA-MB-231 cells suppressed metastasis-related traits including formation of spindle-like morphology, migratory capacity, adhesion to fibronectin, and anoikis. These findings indicate that miR-124 suppresses multiple steps of metastasis by diverse mechanisms in breast cancer cells and suggest a potential application of miR-124 in breast cancer treatment.

[Analysis of microRNA in drug-resistant breast cancer cell line MCF-7/ADR].

OBJECTIVE: To analyze the difference in microRNAs expression between MCF-7 and MCF-7/ADR cells and explore the association between microRNA and drug resistance of breast cancer. METHODS: The drug resistance of MCF-7/ADR cells was evaluated using MTT assay and flow cytometry. Microarray technique and RT-PCR were used to analyze the differential expressions of the microRNA between MCF-7 and MCF-7/ADR cells. RESULTS: The drug resistance index of MCF-7/ADR cells relative to the parental MCF-7 cells was 33.2. The percentages of the side population in MCF-7/ADR and MCF-7 cells were (9.50-/+0.9)% and (0.85-/+0.2)%, respectively. Microarray analysis of MCF-7 to MCF-7/ADR cells identified 36 differentially expressed genes, including 16 up-regulated and 20 down-regulated genes in MCF-7/ADR cells. RT-PCR identified 14 microRNAs that were differentially expressed between MCF-7 and MCF-7/ADR cells, including 7 up-regulated and 7 down-regulated ones in MCF-7/ADR cells. Of these differentially expressed microRNAs, mir-221, mir222, mir-130a, and mir-155 showed significantly increased expression, and mir200a, mir-200b, mir-200c, and mir-421 showed significantly lowered expression in MCF-7/ADR cells as indicated by the results of microarray analysis and RT-PCR. CONCLUSION: MCF-7/ADR cells show a different microRNA expression profile from its parental MCF-7 cells, suggesting the involvement of microRNAs in tumor cell drug resistance. This finding provides a experimental basis for further study of mechanism underlying the drug resistance of breast cancer.