Luteolin reverses OPCML methylation to inhibit proliferation of breast cancer MDA-MB-231 cells / 南方医科大学学报

OBJECTIVE@#To observe the effect of luteolin on the proliferation and expression of OPCML in breast cancer cell line MDA-MB-231.@*METHODS@#Cultured MDA-MB-231 cells were treated with luteolin at the concentrations of 5, 10 and 20 μmol/L for 24 or 48 h. MTT assay was used to detect cell proliferation and flow cytometry was used to detect the cell apoptosis. The expressions of OPCML mRNA and protein were detected using real-time quantitative PCR and Western blotting, respectively. OPCML gene methylation in the promoter region was detected using methylation-specific PCR (MSP), and the activity of methylase in the cells was analyzed.@*RESULTS@#MTT assay showed that treatment with luteolin at 5, 10 and 20 μmol/L for 24 h concentration-dependently decreased the viability of MDA-MB-231 cells ( < 0.05). Flow cytometry also showed that luteolin at different concentrations could induce apoptosis of MDA-MB-231 cells ( < 0.05). Luteolin dose-dependently induced the expression of OPCML mRNA and protein in MDA-MB-231 cells ( < 0.05), down-regulated the methylation status in the promoter region of OPCML gene, up-regulated the level of non-methylated OPCML, and reduced the activity of methylase in the cells ( < 0.05).@*CONCLUSIONS@#Luteolin inhibits the proliferation of MDA-MB-231 breast cancer cells probably by upregulating OPCML expression and its demethylation.

Quercetin protects against lipopolysaccharide-induced cardiac injury in mice / 南方医科大学学报

<p><b>OBJECTIVE</b>To evaluate the protective effect of quercetin against lipopolysaccharide (LPS)-induced cardiac injury in mice.</p><p><b>METHODS</b>C57BL/6J mice were randomized into 4 groups to receive intraperitoneal injection of saline (negative control) or LPS (20 mg/kg), or fed with quercetin (100 mg/kg for 7 days) with or without subsequent LPS injection (quercetin+LPS group and quercetin control group, respectively). Six hour after LPS injection, the mice were tested for cardiac function with an echocardiograph, and the protein expressions of Bax, Bcl-2, iNOS, and eNOS in the myocardium were evaluated with Western blotting; serum NO concentration was also measured. The survival of the mice within 5 days after LPS injection was recorded to draw the survival curve.</p><p><b>RESULTS</b>Quercetin pretreatment significantly improved the cardiac function of LPS-challenged mice (P<0.05), and attenuated LPS-induced increment in myocardial iNOS expression and decrement in eNOS level. LPS significantly increased the myocardial Bax expression and slightly decreased Bcl-2 expression; quercetin pretreatment decreased Bax expression to the control level and significantly lowered Bax/Bcl-2 ratio as compared with the LPS group. Serum NO level was significantly increased by nearly 2.5 folds in LPS-challenged mice, but was markedly decreased with quercetin pretreatment (P<0.05). The 5-day survival rate of LPS-treated mice was 10%, which was increased to 45% in quercetin- pretreated mice (P<0.05).</p><p><b>CONCLUSION</b>Quercetin can alleviate LPS-induced cardiac dysfunctions in mice to increase their survival rate following LPS challenge.</p>

Nucleotide sequencing of E/NS1 gene segment of dengue type 1 viruses isolated in Guangdong Province / 中华实验和临床病毒学杂志

<p><b>OBJECTIVE</b>To analyse the genetic relationship of local strains of dengue type 1 viruses isolated in different years and regions from Guangdong Province, and to explore the genetic links with strains of adjacent countries by comparing with the sequences of relevant strains in Genbank.</p><p><b>METHODS</b>The viral RNAs were extracted and used for one-step reverse transcriptase polymerase chain reaction (RT-PCR) to amplify the partial nucleotide fragments in E/NS1 gene junction which were then cloned into the plasmid pBluescript II SK for sequencing, the results were analysed by DNASTAR software.</p><p><b>RESULTS</b>The phylogenetic tree of the sequenced 14 strains of dengue type 1 viruses branches into two genotypic groups. The nucleotide sequences showed a maximal homologies of 99.2% with Indonesia strains, 100% with Philippines strains and 98.8% with Thailand strains.</p><p><b>CONCLUSIONS</b>The dengue type 1 viruses of Guangdong Province are closely related to the Philippines, Indonesia and Thailand strains, which may indicate the possibility of importation from those countries.</p>