ABSTRACT
BACKGROUND: Triptolide is a structurally unique diterpene triepoxide with potent antitumor activity. However,the effect and mechanism of triptolide on hepatocellular carcinoma (HCC) is not well studied. METHODS: Cells were treated with triptolide, and the anti-HCC activity of triptolide was evaluated using flow cytometry, western blot, and xenograft studies. MicroRNA microarray and quantitative reverse-transcription polymerase chain reaction was used to identify differential microRNAs induced by triptolide. Chromatin immunoprecipitation assay was employed to study the interaction between c-Myc and genomic regions of miR106b-25. MicroRNAs overexpression and knockdown experiments were performed to determine the role of these microRNAs in triptolide-induced apoptosis. RESULTS: Triptolide inhibited cell proliferation and induced marked apoptosis in multiple HCC cell lines with different p53 status. Several signaling molecules involved in different pathways were altered after the treatment of triptolide. Xenograft tumor volume was significantly reduced in triptolide-treated group compared with vehicle control group. Two miRNA clusters, miR-17-92 and miR-106b-25, were significantly suppressed by triptolide, which resulted in the upregulation of their common target genes, including BIM, PTEN, and p21. In HCC samples, high levels of these miRNA clusters correlated with shorter recurrence free survival. Triptolide inhibited the expression of theses miRNAs in a c-Myc-dependent manner, which enhanced triptolide-induced cell death. We further showed that triptolide down-regulated the expression of c-Myc through targeting ERCC3, a newly identified triptolide-binding protein. CONCLUSIONS: The triptolide-induced modulation of c-Myc/miRNA clusters/target genes axis enhances its potent antitumor activity, which indicates that triptolide serves as an attractive chemotherapeutic agent against HCC.
Subject(s)
Carcinoma, Hepatocellular/genetics , Carcinoma, Hepatocellular/metabolism , Diterpenes/pharmacology , Gene Expression Regulation, Neoplastic/drug effects , Liver Neoplasms/genetics , Liver Neoplasms/metabolism , MicroRNAs/genetics , Phenanthrenes/pharmacology , Proto-Oncogene Proteins c-myc/metabolism , Animals , Antineoplastic Agents, Alkylating/pharmacology , Carcinoma, Hepatocellular/mortality , Carcinoma, Hepatocellular/pathology , Cell Death/drug effects , Cell Death/genetics , Cell Line, Tumor , Cell Proliferation , DNA Helicases/genetics , DNA-Binding Proteins/genetics , Disease Models, Animal , Epoxy Compounds/pharmacology , Gene Expression Profiling , Humans , Liver Neoplasms/mortality , Liver Neoplasms/pathology , Mice , Oncogenes , RNA Interference , Xenograft Model Antitumor AssaysABSTRACT
A novel label-free aptamer surface-enhanced Raman scattering (SERS) sensor for trace malathion residue detection was proposed. In this process, the binding of malathion molecule with aptamer is identified directly. The silver nanoparticles modified with positively charged spermine served as enhancing and capture reagents for the negatively charged aptamer. Then, the silver nanoparticles modified by aptamer were used to specifically capture the malathion. The SERS background spectra of spermine, aptamer, and malathion were recorded and distinguished with the spectrum of malathion-aptamer. To enhance the characteristic peak signal of malathion captured by the aptamer, the aggregate reagents (NaCl, KCl, MgCl2) were compared and selected. The selectivity of this method was verified in the mixed-pesticide standard solution, which included malathion, phosmet, chlorpyrifos-methyl, and fethion. Results show that malathion can be specifically identified when the mixed-pesticide interferences existed. The standard curve was established, presenting a good linear range of 5×10-7 to 1×10-5mol·L-1. The spiked experiments for tap water show good recoveries from 87.4% to 110.5% with a relative standard deviation of less than 4.22%. Therefore, the proposed label-free aptamer SERS sensor is convenient, specifically detects trace malathion residues, and can be applied for qualitative and quantitative analysis of other pesticides.
ABSTRACT
OBJECTIVE: To observe in vitro and in vivo effects of triptolide on growth inhibition and apoptosis of osteosarcoma cells, and to further explore its correlated molecular mechanisms. METHODS: The growth inhibition effects of triptolide on osteosarcoma cells were detected using MTT assay. The apoptosis was detected using flow cytometry.The protein expressions of associated signals were detected using Western blot. The in vivo anti-osteosarcoma effects of triptolide were verified in osteosarcoma nude mice. The in vivo associated protein expressions were detected using immunohistochemistry (IHC). RESULTS: Triptolide could significantly inhibit the proliferation of various osteosarcoma cells. Besides, it could induce their apoptosis. Triptolide triggered the mitochondrial dependent apoptotic pathway, significantly inhibited the in vivo growth of osteosarcoma cells, and caused in vivo apoptosis. CONCLUSIONS: Triptolide induced apoptosis of osteosarcoma cells partially through activating mitochondria associated apoptosis signal pathway. Triptolide also induced apoptosis of osteosarcoma cells and inhibited their in vivo growth in nude mice.
