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The epithelial–mesenchymal transition (EMT) is a key process in tumor invasion and migration. Transforming growth factor-βs (TGF-βs) are multifunctional growth factors and powerful modulators of the EMT. Here, we investigated the relationship between TGF-β expression and invasion by treated triple-negative breast cancer (TNBC) cells. Our results show that invasion capacity of TNBC cells was markedly higher than that of non-TNBC cells. In addition, EMT-related gene signatures, including vimentin (vim), fibronectin (FN), snail, and slug were highly expressed in TNBC cells. Interestingly, our results show that TGF-β1 and β2 mRNA expression levels were higher in TNBC cells than those in non-TNBC cells. Thus, we examined the effect of the TGF-β receptor I/II inhibitor LY2109761 on EMT-related gene expression and cell motility. Our data show that vim, FN, and slug mRNA expression levels dose-dependently decreased in response to LY2109761. TNBC cell motility also decreased in response to LY2109761. Finally, we investigated the effect of LY2109761 on TGF-β1 or TGF-β2-induced E-cadherin (E-cad), vim, and FN mRNA and protein expression. The reduction in E-cad and induction of vim and FN expression by TGF-β1 or TGF-β2 were completely reversed by LY2109761 treatment in HCC1806 TNBC cells. Taken together, we demonstrated that elevated TGF-β expression triggers invasion and migration by TNBCs through the EMT process. Inhibiting the TGF-β signaling pathway is considered a promising therapeutic strategy for treating TNBC. [ABSTRACT FROM AUTHOR]

Complex of platelet-derived growth factor (PDGF) isoforms and PDGF receptors have important functions in the regulation of growth and survival of various cell types. Herein, it was found that aberrant PDGFC expression is closely associated with survival rates in triple-negative breast cancer (TNBC) patients. In addition, PDGFC expression was identified to be significantly increased in TNBC cells unlike other subtypes such as PDGFA, PDGFB, and PDGFD. Apparently, the effects of specific PDGF receptor (PDGFR) inhibitors such as sunitinib and ponatinib on HCC1806 and Hs578T TNBC cells were investigated. Both inhibitors decreased cell viability in a dose-dependent manner. In addition, the inhibitors completely inhibited cell growth in both the cell lines and decreased the expression of matrix metalloproteinase-1 (MMP-1), one of the metastasis-related genes. Cell migration was also decreased by the inhibitors. Finally, the combined effects of the inhibitors with doxorubicin (DOX) were investigated. The results showed that the combination of two PDGFR inhibitors with DOX inhibited the growth of cells and enhanced the apoptotic cell death more uniformly than DOX. Consequently, it is demonstrated that PDGFR inhibitors, sunitinib and ponatinib hold the potential for effective treatment of TNBC. [ABSTRACT FROM AUTHOR]

Please cite this paper as: Activation of toll-like receptors 2, 3 or 5 induces matrix metalloproteinase-1 and -9 expression with the involvement of MAPKs and NF-κB in human epidermal keratinocytes. Experimental Dermatology 2010; 19: e44-e49. Abstract: Toll-like receptors (TLRs) on epidermal keratinocytes are the first line of defense against microbe invasion, and matrix metalloproteases (MMPs) regulate inflammation, cell migration and wound healing. In this study, we demonstrate that the mRNA and protein expressions of MMP-1 and MMP-9 in human epidermal keratinocytes are induced by ligands for TLR2, TLR3 and TLR5 [Pam3CSK4, Poly(I:C) and flagellin, respectively] in a dose-dependent manner. We also found that the ligands for TLR2, TLR3 and TLR5 activate the MAP kinases, JNK and p38 MAPK, but not ERK1/2. Furthermore, treatment with the ligands for TLR2, TLR3 and TLR5 also induced the degradation of IκB-α and activated the nuclear translocation of NF-κB. MMP-1 induction by the ligands for TLR2, TLR3 and TLR5 was inhibited by pretreatment with BAY11-7082 (NF-κB inhibitor) or SP600125 (JNK inhibitor), whereas MMP-9 expression was inhibited by pretreatment with BAY11-7082, SP600125 or SB203580. These findings demonstrate that the activation of TLR2, TLR3 or TLR5 induces the expression of MMP-1 and MMP-9 in human epidermal keratinocytes. In addition, NF-κB or JNK mediated the MMP-1 expression induced by TLR2, TLR3 and TLR5, whereas NF-κB, JNK or p38 MAPK mediated the MMP-9 expression induced by TLR2, TLR3 and TLR5. [ABSTRACT FROM AUTHOR]

Background: The biological effects of CD24 (FL-80) cross-linking on breast cancer cells have not yet been established. We examined the impact of CD24 cross-linking on human breast cancer cell line MCF-7. Methods: MCF-7 and MDA-MB-231 cells were treated with anti-rabbit polyclonal IgG or antihuman CD24 rabbit polyclonal antibodies to induce cross-linking, and then growth was studied. Changes in cell characteristics such as cell cycle modulation, cell death, survival in threedimensional cultures, adhesion, and migration ability were assayed after CD24 cross-linking in MCF-7. Results: Expression of CD24 was analyzed by flow cytometry in MDA-MB-231 and MCF-7 cells where 2% and 66% expression frequencies were observed, respectively. CD24 cross-linking resulted in time-dependent proliferation reduction in MCF-7 cells, but no reduction in MDA-MB- 231 cells. MCF-7 cell survival was reduced by 15% in three-dimensional culture after CD24 crosslinking. Increased MCF-7 cell apoptosis was observed after CD24 cross-linking, but no cell cycle arrest was observed in that condition. The migration capacity of MCF-7 cells was diminished by 30% after CD24 cross-linking. Conclusion: Our results showed that CD24 cross-linking induced apoptosis and inhibited migration in MCF-7 breast cancer cells. We conclude that CD24 may be considered as a novel therapeutic target for breast cancer. [ABSTRACT FROM AUTHOR]