The effect of targeted regulation of LATS2 by LncRNA BCAR4 on proliferation, migration and apoptosis of HCC cells.

OBJECTIVE: This study explored and analyzed the effects of targeted regulation of LATS2 by LncRNA BCAR4 on the proliferation, migration and apoptosis of hepatocellular carcinoma (HCC). METHOD: We detected the expression of LncRNA, BCAR4 and LATS2 mRNA in liver hepatocellular carcinoma HepG2 cells and normal hepatocellular cells LO2 by RT-PCR. HepG2 cells were divided into BCAR4-siRNA, NC-siRNA and control groups. We detected the targeted regulation of LncRNA BCAR4 on LATS2 by luciferase gene assay, and measured the proliferation, migration and apoptosis of cells in each group by RT-PCR, MTT, Transwell and flow cytometry, respectively. RESULTS: The relative expression of LncRNA BCAR4 in HepG2 cells was critically higher than that in LO2 cells (P<0.05), while LATS2 mRNA in HepG2 cells was significantly less than that in LO2 cells (P<0.05). Compared with NC siRNA group, the content of luciferase in BCAR4 siRNA group was much higher (P<0.05); The relative expression of LncRNA BCAR4 in BCAR4 siRNA group decreased dramatically than that in NC-siRNA and control group (P<0.05), and the relative expression of LATS2 mRNA increased remarkably than that in NC-siRNA group and control group (P<0.05). The OD value of BCAR4 siRNA group was dramatically higher than that of NC-siRNA group and control group after 48 h and 72 h culture (P<0.05). The quantity of invaded cells in BCAR4 siRNA group was markedly less than that in NC-SIRNA group and control group (P<0.05). Cell apoptosis rate in BCAR4-siRNA group was significantly higher than that of NC-siRNA group and control group (P<0.05). CONCLUSION: LncRNA BCAR4 can regulate the LATS2 expression, and inhibiting the expression of LncRNA BCAR4 can inhibit proliferation, invasion of HepG2 cells and induce its apoptosis, which finding provides a certain reference for the targeted therapy of liver cancer.

Enhanced Fire Safety of Rigid Polyurethane Foam via Synergistic Effect of Phosphorus/Nitrogen Compounds and Expandable Graphite.

In order to explore highly efficient flame-retardant rigid polyurethane foam (RPUF), phosphorus/nitrogen compounds and expandable graphite (EG) were successfully incorporated into RPUF by a free one-spot method. The combustion results showed that the fire safety of the RPUF samples was remarkably improved by the addition of phosphoric/nitrogen compounds and EG. With the incorporation of 22.4 wt.% phosphorus/nitrogen compounds and 3.2 wt.% EG, the RPUF composites achieved UL-94 V-0 rating. Besides, the total heat release and total smoke release of RPUF composites were reduced by 29.6% and 32.4% respectively, compared to those of the pure RPUF sample. PO• and PO2• together with nonflammable gaseous products were evolved from phosphoric/nitrogen compounds in the gas phase, which quenched the flammable free radicals in the matrix and diluted the concentration of combustible gaseous products generated from PRUF during combustion. The compact char residues which acted as excellent physical barriers were formed by catalysis of EG and phosphoric/nitrogen compounds in the condense phase. The fire hazard of RPUF was significantly reduced by the synergistic effect of phosphorus-nitrogen compounds and EG. This work provides a promising strategy to enhance the fire safety of RPUF.

Highly Effective Flame-Retardant Rigid Polyurethane Foams: Fabrication and Applications in Inhibition of Coal Combustion.

The extemporaneous combustion of coal remains a major threat to safety in coal mines because such fire accidents result in casualties and significant property loss, as well as serious environmental pollution. This work proposed the fabrication of flame-retardant rigid polyurethane foam (RPUF) containing expandable graphite as char expander/sealant with melamine phosphosphate and 2-carboxyethyl (phenyl)phosphinic acid as char inducer and radical trapping agents. The as-prepared RPUF successfully inhibited coal combustion by forming thermally stable high graphitic content expandable intumescent char sealing over the coal. The RPUF achieved UL-94 V-0 rating in addition to significant reductions in peak heat release, total heat release, and CO and CO2 yields. The external and the internal residual char structure was studied by X-ray photoelectron spectra, Raman spectroscopy, and real-time Fourier transform infrared spectra techniques, and a flame-retardant mode of action has been proposed. This work provides important insight into a facile fabrication of highly efficient and economical flame-retardant RPUF to inhibit the spontaneous combustion of coal.

Up-regulating CYP3A4 expression in C3A cells by transfection with a novel chimeric regulator of hPXR-p53-AD.

Most hepatoma cell lines lack proper expression and induction of CYP3A4 enzyme, which limits their use for predicting drug metabolism and toxicity. Nuclear receptor pregnane X receptor (PXR) has been well recognized for its critical role in regulating expression of CYP3A4 gene. However, its physiological activity of binding to the particular site of promoter is significantly weakened in hepatic cell lines. To address this problem, we created "chimeric PXR" constructs by appending a strong activation domain (AD) from p53 subunit to either N- or C- termini of the human PXR (hPXR), that is, hPXR-p53 and p53-hPXR. C3A, a hepatoma cell line, was used as the cell model to test the regulation effect of chimeric hPXR over wild type (WT) hPXR on CYP3A4 expression at gene, protein, and metabolism levels, respectively. Compared with C3A cells transiently transfected with WT hPXR, the activity of CYP3A4.XREM.luc reporter gene in C3A cells transfected with hPXR-p53 or p53-hPXR increased 5- and 9-fold respectively, and the levels of CYP3A4 mRNA expression increased 3.5- and 2.6-fold, respectively. C3A cells stably transfected with hPXR-p53-AD exhibited an improved expression of CYP3A4 at both gene (2-fold) and protein (1.5-fold) levels compared to WT C3A cells. Testosterone, a CYP3A4-specific substrate, was used for detecting the metabolism activity of CYP3A4. No testosterone metabolite could be detected in microsomes from WT C3A cells and WT C3A cells-based array, while the formation of 6ß-hydroxytestosterone metabolite in the transfected cells was 714 and 55 pmol/mg protein/min, respectively. In addition, all the above expression levels in the transfected cell models could be further induced with additional treatment of Rifampicin, a specific inducer for CYP3A4. In conclusion, our study established a proof-of-principle example that genetic modification with chimeric hPXR-p53-AD could improve CYP3A4 metabolism ability in hepatic cell line.