Up-regulation of miR-182 by ß-catenin in breast cancer increases tumorigenicity and invasiveness by targeting the matrix metalloproteinase inhibitor RECK.

BACKGROUND: MiR-182 is a member of the miR-183 cluster located at human chromosome 7q32 region and is up-regulated in human cancers. We study the regulation of miR-182 expression and its oncogenic role. METHODS: MiR-182 level was investigated by real-time reverse transcription-PCR. Chromatin immunoprecipitation assay was used to confirm promoter binding of transcription factors. The correlation between miR-182 and RECK was analyzed by Western blotting, real-time RT-PCR and 3(')-untranslated region reporter assay. Zymography, matrix metalloproteinase activity, invasion and colony formation were used to study the tumorigenic activity. RESULTS: MiR-182 is over-expressed in human breast tumor tissues and cell lines. Inhibition or knockdown of ß-catenin reduced miR-182 level in MDA-MB-231 cells. ChIP assay confirmed the binding of ß-catenin on miR-182 promoter. Anti-miR-182 increased the MMP inhibitor RECK protein in MDA-MB-231 cells while pre-miR-182 reduced RECK protein but not mRNA in normal mammary epithelial H184B5F5/M10 cells. Restoration of RECK protein by anti-miR-182 attenuated MMP-9 activity, cell invasion and colony formation. Ectopic expression of miR-182 inhibited restoration of RECK protein by ß-catenin inhibitor indicating miR-182 is important for ß-catenin-induced down-regulation of RECK. An inverse association between miR-182 and RECK was demonstrated in breast tumor tissues. CONCLUSIONS: We provide evidence that miR-182 is up-regulated by ß-catenin signaling pathway in breast cancer and its up-regulation increases tumorigenicity and invasiveness by repressing RECK. GENERAL SIGNIFICANCE: Our data demonstrate for the first time that miR-182 expression is controlled by ß-catenin. In addition, we identify a new miR-182 target RECK which is important for miR-182-induced tumorigenesis.

A novel sialyltransferase inhibitor AL10 suppresses invasion and metastasis of lung cancer cells by inhibiting integrin-mediated signaling.

Aberrant sialylation catalyzed by sialyltransferases (STs) is frequently found in cancer cells and is associated with increased cancer metastasis. However, ST inhibitors developed till now are not applicable for clinical use because of their poor cell permeability. In this study, a novel ST inhibitor AL10 derived from the lead compound lithocholic acid identified in our previous study is synthesized and the anti-cancer effect of this compound is studied. AL10 is cell-permeable and effectively attenuates total sialylation on cell surface. This inhibitor shows no cytotoxicity but inhibits adhesion, migration, actin polymerization and invasion of alpha-2,3-ST-overexpressing A549 and CL1.5 human lung cells. Inhibition of adhesion and migration by AL10 is associated with reduced sialylation of various integrin molecules and attenuated activation of the integrin downstream signaling mediator focal adhesion kinase. More importantly, AL10 significantly suppresses experimental lung metastasis in vivo without affecting liver and kidney function of experimental animals as determined by serum biochemical assays. Taken together, AL10 is the first ST inhibitor, which exhibits potent anti-metastatic activity in vivo and may be useful for clinical cancer treatment.

New idea for hair transplantation to preserve more donor hair follicles.

Higher risk of rapid progression in alopecia or male pattern baldness was observed in men who had family history. This could result from accumulation of DHT in hair follicles. Hair follicles on frontal region are more vulnerable to DHT. With development of minimal invasive hair transplantation surgery, hair follicles transplantation could be performed from frontal or occipital region to frontal region. However, limited hair follicles remained a problem. With development of technology of vitrification, we suggested extracting hair follicles from frontal region without affecting the appearance and preserving them with vitrification when the patient was young. When alopecia progressively developed, these extracted hair follicles would increase the donor number of hair follicles used for transplantation, which could extend longer dense hair appearance.

MiR-182 promotes proliferation and invasion and elevates the HIF-1α-VEGF-A axis in breast cancer cells by targeting FBXW7.

The feature of imperfect complementary effect of miRNAs to mRNAs implies that miRNAs may simultaneously target different mRNAs to affect multiple aspects of tumorigenesis. In our previous results, we demonstrated that miR-182 was over-expressed in breast cancer cell lines and clinical tumor tissues and its up-regulation increased tumorigenicity and invasiveness by repressing a tumor suppressor RECK. In this study, we showed that overexpression miR-182 regulated actin distribution and filopodia formation to increase invasiveness of breast cancer cells. In addition, miR-182 enhanced cell cycle progression and proliferation. We further identified the E3 ubiquitin-protein ligase FBXW7 as a target gene of miR-182. We also demonstrated that miR-182-overexpressing cells were highly sensitive to hypoxia. Under hypoxic condition, HIF-1α and VEGF-A proteins were significantly upregulated in these cells. In addition, the conditioned medium of miR-182-overexpressing cells contained more VEGF-A than the control cells and induced angiogenesis more efficiently in vitro. All these effects could be counteracted by ectopic expression of FBXW7 in cells or neutralization of VEGF-A in the conditioned media by specific antibody. Finally, our data showed that miR-182 expression was inversely correlated with FBXW7 in breast tumor tissues. In conclusion, our study explores a novel mechanism by which miR-182 elevates HIF-1α expression to promote breast cancer progression.

Targeting of TGF-ß-activated protein kinase 1 inhibits chemokine (C-C motif) receptor 7 expression, tumor growth and metastasis in breast cancer.

TGF-ß-activated protein kinase 1 (TAK1) is a critical mediator in inflammation, immune response and cancer development. Our previous study demonstrated that activation of TAK1 increases the expression of chemokine (C-C motif) receptor 7 (CCR7) and promotes lymphatic invasion ability of breast cancer cells. However, the expression and association of activated TAK1 and CCR7 in breast tumor tissues is unknown and the therapeutic effect by targeting TAK1 is also unclear. We showed that activated TAK1 (as indicated by phospho-TAK1) and its binding protein TAB1 are strongly expressed in breast tumor tissues (77% and 74% respectively). In addition, increase of phospho-TAK1 or TAB1 is strongly associated with overexpression of CCR7. TAK1 inhibitor 5Z-7-Oxozeaenol (5Z-O) inhibited TAK1 activity, suppressed downstream signaling pathways including p38, IκB kinase (IKK) and c-Jun N-terminal kinase (JNK) and reduced CCR7 expression in metastatic MDA-MB-231 cells. In addition, 5Z-O repressed NF-κB- and c-JUN-mediated transcription of CCR7 gene. Knockdown of TAB1 attenuated CCR7 expression and tumor growth in an orthotopic animal study. More importantly, lymphatic invasion and lung metastasis were suppressed. Collectively, our results demonstrate that constitutive activation of TAK1 is frequently found in human breast cancer and this kinase is a potential therapeutic target for this cancer.

Lower Urinary Tract Symptoms Are Associated with Increased Risk of Dementia among the Elderly: A Nationwide Study.

Studies show a strong association between dementia and lower urinary tract symptoms (LUTS). The aim of this study was to investigate whether LUTS are a risk factor for cognitive impairment. We enrolled 50-year-old and older subjects with LUTS (LUTS([+])) (n = 6801) and controls without LUTS (LUTS([-])) (n = 20,403) from Taiwan's National Health Insurance Research Database. LUTS, dementia, and other confounding factors are defined by International Classification of Diseases, Ninth Revision, Clinical Modification Codes. Participants were recruited from 2000 to 2004 and then followed up until death or the end of 2011. The outcome was the onset of dementia, which was assessed using Poisson regression analysis, Cox hazards models, and Kaplan-Meier survival curves. The incidence of dementia was significantly higher in the LUTS([+]) group than in the LUTS([-]) group (124.76 versus 77.59/1000 person-years). The increased risk of dementia related to LUTS remained significant after adjustment for potential confounders (adjusted hazard ratio (AHR): 1.61, 95% confidence interval (CI) 1.47-1.76, P < 0.0001) and higher than that related to cerebrovascular disease (AHR: 1.43, 95% CI 1.26-1.61, P < 0.0001). The outcome suggests the need for early screening and appropriate intervention to help prevent cognitive impairment of patients with LUTS.

Inhibition of chemokine (C-C motif) receptor 7 sialylation suppresses CCL19-stimulated proliferation, invasion and anti-anoikis.

Chemokine (C-C motif) receptor 7 (CCR7) is involved in lymph-node homing of naive and regulatory T cells and lymphatic metastasis of cancer cells. Sialic acids comprise a group of monosaccharide units that are added to the terminal position of the oligosaccharide chain of glycoproteins by sialyation. Recent studies suggest that aberrant sialylation of receptor proteins contributes to proliferation, motility, and drug resistance of cancer cells. In this study, we addressed whether CCR7 is a sialylated receptor protein and tried to elucidate the effect of sialylation in the regulation of signal transduction and biological function of CCR7. Our results demonstrated that α-2, 3-sialyltransferase which catalyze sialylation reaction in vivo was overexpressed in breast tumor tissues and cell lines. Lectin blot analysis clearly demonstrated that CCR7 receptor was sialyated in breast cancer cells. Chemokine (C-C motif) ligand 19 (CCL19), the cognate ligand for CCR7, induced the activation of extracellular signal-regulated kinase (ERK) and AKT signaling and increased the expression of cell cycle regulatory proteins and proliferation of breast cancer cells. When cells were pre-treated with a sialyltransferase inhibitor AL10 or sialidase, CCL19-induced cell growth was significantly suppressed. CCL19 also increased invasion and prevented anoikis by up-regulating pro-survival proteins Bcl-2 and Bcl-xL. Inhibition of sialylation by AL10 totally abolished these effects. Finally, we showed that AL10 inhibited tumorigenicity of breast cancer in experimental animals. Taken together, we demonstrate for the first time that CCR7 receptor is a sialylated protein and sialylation is important for the paracrine stimulation by its endogenous ligand CCL19. In addition, inhibition of aberrant sialylation of CCR7 suppresses proliferation and invasion and triggers anoikis in breast cancer cells. Targeting of sialylation enzymes may be a novel strategy for breast cancer treatment.