This study aimed to investigate the role of fatty acid synthase (FASN) in the epithelial-mesenchymal transition (EMT) of breast cancer cells. MCF-7 cells and MCF-7 cells overexpressing mitogen-activated protein kinase 5 (MCF-7-MEK5) were used in this study. MCF-7-MEK5 cells showed stable EMT characterized by increased vimentin and decreased E-cadherin expression. An In vivo animal model was established using the orthotopic injection of MCF-7 or MCF-7-MEK5 cells. Real-time quantitative PCR and western blotting were used to detect the expression levels of FASN and its downstream proteins liver fatty acid-binding protein (L-FABP) and VEGF/VEGFR-2 in both in vitro and in vivo models (nude mouse tumor tissues). In MCF-7-MEK5 cells, significantly increased expression of FASN was associated with increased levels of L-FABP and VEGF/VEGFR-2. Cerulenin inhibited MCF-7-MEK5 cell migration and EMT, and reduced FASN expression and down-stream proteins L-FABP, VEGF, and VEGFR-2. MCF-7-MEK5 cells showed higher sensitivity to Cerulenin than MCF-7 cells. Immunofluorescence revealed an increase of co-localization of FASN with VEGF on the cell membrane and with L-FABP within MCF-7-MEK5 cells. Immunohistochemistry further showed that increased percentage of FASN-positive cells in the tumor tissue was associated with increased percentages of L-FABP- and VEGF-positive cells and the Cerulenin treatment could reverse the effect. Altogether, our results suggest that FASN is essential to EMT possibly through regulating L-FABP, VEGF and VEGFR-2. This study provides a theoretical basis and potential strategy for effective suppression of malignant cells with EMT.
TERT attenuates astrocyte proliferation and promotes neuronal survival in the developing rat brain after hypoxia-ischemia, partly through its enhancement of p15 and neurotrophin-3 expression in astrocytes.
Hypoxia is a common feature of solid tumors including stomach cancer (SC) and is closely associated with cancer malignant progression. N6-methyladenosine (m6A), a common modification on RNA, is involved in the regulation of RNA fate and hypoxic responses in cancers. However, the interaction between m6A reader insulin-like growth factor-II mRNA-binding protein 3 (IGF2BP3) and SC hypoxic microenvironment is poorly defined. In the present study, expression levels of IGF2BP3 and hypoxia inducible factor-1α (HIF1A) were examined by bioinformatics analysis and RT-qPCR and western blot assays. Cell migratory ability was assessed through Transwell and wound healing assays. The angiogenic potential was evaluated by VEGF secretion, tube formation, and chick embryo chorioallantoic membrane (CAM) assays. The interaction between IGF2BP3 and HIF1A was explored using bioinformatics analysis and RIP and luciferase reporter assays. The results showed that IGF2BP3 and HIF1A were highly expressed in SC tissues and hypoxia-treated SC cells. IGF2BP3 knockdown inhibited hypoxia-induced cell migration and angiogenesis in SC. IGF2BP3 positively regulated HIF1A expression by directly binding to a specific m6A site in the coding region of HIF1A mRNA in SC cells. HIF1A overexpression abrogated the effects of IGF2BP3 knockdown on hypoxia-induced cell migration and angiogenesis in SC. In conclusion, IGF2BP3 knockdown inhibited hypoxia-induced cell migration and angiogenesis by down-regulating HIF1A in SC.
A binding site of GL is present on the surface of rat hepatocytes, BSA-NP-GL may be internalized via this site by hepatocytes and can be used as a drug carrier for active targeting of delivery drugs to hepatocytes.
Dermatopontin (DPT) was recently found as a downstream target of vitamin D receptor, which is a key molecule in the 1,25-dihydroxy-vitamin D(3) anti-hepatoma proliferation pathway. MCTx-1 from Millepora, a homolog of DPT, is identified as a cytotoxin towards leukemia cells. The aim of this study was to analyze DPT expression in hepatocellular carcinoma (HCC) based on the analysis for DPT gene in normal tissues in order to estimate its function in the progression of HCC. DPT mRNA expression was analyzed in normal tissues and HCC cell lines by RT-PCR, and in HCC tissue by RT-PCR and real-time PCR. Its protein was examined in HCC tissues by Western blot and immunohistochemistry assays. Meanwhile, transforming growth factor-beta1 (TGF-beta1) that is closely associated with HCC and DPT was observed by immunohistochemistry in HCC tissues. The results showed that DPT mRNA was strongly expressed in human fetal and adult liver, kidney, and spleen, weakly in ovary and heart, and absent in other tissues and HCC cell lines examined. Its mRNA was significantly downregulated in HCC tissues, while its protein was weakly expressed in tumor compared with non-tumor. DPT is located mainly in the cytoplasm of several cell types in the liver; it has been identified also in the extracellular matrix of the skin. TGF-beta1 was observed in extensive tumor tissue of HCC. This fact suggests that DPT can play various roles in different tissues and might be a molecule related to carcinogenesis and the progression of HCC via possible interaction with TGF-beta1 and other potential mechanisms.
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