[Role of long noncoding RNA MALAT1 promotes the occurrence and progression of cutaneous squamous cell carcinoma].

OBJECTIVE: To investigate the role of long noncoding RNA MALAT1 in the occurrence and progression of cutaneous squamous cell carcinoma (CSCC). METHODS: Fifty-five tissue samples of CSCC and 10 normal epidermal tissues were collected for examination of the expression of MALAT1 using q-PCR and in situ hybridization. Human CSCC A431 cells were transfected with small interfering RNAs (siNC, siMALAT1-1, and siMALAT1-2) using Lipofectamine2000 to knock down MALAT1 gene, and the changes in the cell migration, invasion, mobility and proliferation were analyzed using Transwell assay, wound healing assay, and CCK-8 assay; the changes in the expressions of the related factors of epithelial-mesenchymal transition (EMT), including E-cadherin, vimentin, and ß-catenin, were detected using qRT-PCR. RESULTS: Compared with normal tissues, CSCC tissues of different grades of differentiation all showed significantly increased expression of MALAT1 (P<0.001). In A431 cells, MALAT1 knockdown with siRNAs resulted in significantly lowered cell proliferation (P<0.001), migration (P<0.01), invasion (P<0.01), and mobility (P<0.01). Knocking down MALAT1 gene also caused significantly increased expressions of E-cadherin and ß-catenin (P<0.01) and lowered the expression of vimentin (P<0.01) in A431 cells. CONCLUSION: The long noncoding RNA MALAT1 promotes the occurrence and progression of CSCC and can potentially serve as a therapeutic target in treatment of CSCC.

Heavy metals in wild marine fish from South China Sea: levels, tissue- and species-specific accumulation and potential risk to humans.

Heavy metal pollution in marine fish has become an important worldwide concern, not only because of the threat to fish in general, but also due to human health risks associated with fish consumption. To investigate the occurrence of heavy metals in marine fish species from the South China Sea, 14 fish species were collected along the coastline of Hainan China during the spring of 2012 and examined for species- and tissue-specific accumulation. The median concentrations of Cd, Cr, Cu, Zn, Pb and As in muscle tissue of the examined fish species were not detectable (ND), 2.02, 0.24, 2.64, 0.025, and 1.13 mg kg(-1) wet weight, respectively. Levels of Cu, Zn, Cd and Cr were found to be higher in the liver and gills than in muscle, while Pb was preferentially accumulated in the gills. Differing from other heavy metals, As did not exhibit tissue-specific accumulation. Inter-species differences of heavy metal accumulation were attributed to the different habitat and diet characteristics of marine fish. Human dietary exposure assessment suggested that the amounts of both Cr and As in marine wild fish collected from the sites around Hainan, China were not compliant with the safety standard of less than 79.2 g d(-1) for wild marine fish set by the Joint FAO/WHO Expert Committee on Food Additives. Further research to identify the explicit sources of Cr and As in marine fish from South China Sea should be established.

Relationships between degree of polymerization and antioxidant activities: a study on proanthocyanidins from the leaves of a medicinal mangrove plant Ceriops tagal.

Tannins from the leaves of a medicinal mangrove plant, Ceriops tagal, were purified and fractionated on Sephadex LH-20 columns. 13C nuclear magnetic resonance (13C-NMR), reversed/normal high performance liquid chromatography electrospray ionization mass spectrometry (HPLC-ESI MS) and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDT-TOF MS) analysis showed that the tannins were predominantly B-type procyanidins with minor A-type linkages, galloyl and glucosyl substitutions, and a degree of polymerization (DP) up to 33. Thirteen subfractions of the procyanidins were successfully obtained by a modified fractionation method, and their antioxidant activities were investigated using 2,2-diphenyl-1-picrylhydrazyl (DPPH) scavenging capacity and ferric reducing antioxidant power (FRAP) method. All these subfractions exhibited potent antioxidant activities, and eleven of them showed significantly different mean DP (mDP) ranging from 1.43±0.04 to 31.77±1.15. Regression analysis demonstrated that antioxidant activities were positively correlative with mDP when around mDP <10, while dropped and then remained at a level similar to mDP = 5 with around 95 µg ml(-1) for DPPH scavenging activity and 4 mmol AAE g(-1) for FRAP value.

Differential responses to UVB irradiation in human keratinocytes and epidermoid carcinoma cells.

OBJECTIVE: To examine UVB-induced responses in normal human keratinocytes (HaCaT) and epidermoid carcinoma cells (A431) at the cellular and molecular level, and investigated the protective effect of salidroside. METHODS: Cells irradiated by UVB at various dosage and their viability was assessed by MTT assays, cell cycle was analysed by flow cytometry. The expression of NF-κB, BCL-2, and CDK6 after 50 J/m(2) UVB irradiation were detected by RT-PCR and western blotting. RESULTS: Our results confirmed greater tolerance of A341 cells to UVB-induced damage such as cell viability and cell cycle arrest, which was accompanied by differential expression changes in NF-κB, BCL-2, and CDK6. UVB exposure resulted in HaCaT cells undergoing G(1)-S phase arrest. When treated with salidroside, HaCaT survival was significantly enhanced following exposure to UVB, suggesting great therapeutic potential for this compound. CONCLUSION: Taken together, our study suggests that A431 respond differently to UVB than normal HaCaT cells, and supports a role for NF-κB, CDK6, and BCL-2 in UVB-induced cell G(1)-S phase arrest. Furthermore, salidroside can effectively protect HaCaT from UVB irradiation.

[Mechanisms of ultraviolet B irradiation-induced injuries in 16HBE cells].

OBJECTIVE: To investigate the biological effects of ultraviolet B (UVB) irradiation on human bronchial epithelial cells (16HBE cells) and explore the possible mechanism. METHODS: The survival rates of 16HBE cells were detected by MTT assay at 12 h after UVB irradiation at different doses (0, 10, 30, 50, 70, and 100 J/m(2)) or at 50 J/m(2) for different durations (2, 4, 8, 12, and 24 h). The DNA ladder was detected by agarose gel electrophoresis, the cell cycle changes were analyzed by flow cytometry, and the expression of nuclear factor-κB (NF-κB)/p65 protein was assayed by Western blotting following the exposures. RESULTS: UVB irradiation of the cells resulted in lowered cell survival rates, DNA fragmentation, S phase arrest and up-regulation of NF-κB/p65 protein expression. CONCLUSIONS: UVB irradiation can induce growth inhibition and apoptosis of 16HBE cells, in which process NF-κB protein may play a key role.

[Distribution of Hg in mangrove plants and correlation with Hg speciation in sediments].

Plant is an important role in biogeochemical cycle of Hg. The aim of this study is to ascertain Hg accumulation in several kinds of mangrove plants, and to discuss relationship among Hg concentrations in mangrove plants and different Hg speciation in sediments. Contents of total mercury (THg) in mangrove plants and sediments were determined. Hg speciation was determined with a modified Tessier's method. Contents of THg of the mangrove plants were in the range of 817.5-3 197.6 ng/g. In detail, Hg concentration was (1 579.4 +/- 1 326.8) ng/g in Kandelia candel, (2 115.1 +/- 1 892.3) ng/g in Aegiceras corniculatum, (2 159.3 +/- 1 678.7) ng/g in Avicennia marina, (2 566.5 +/- 821.6) ng/g in Bruguiera gymnorrhiza, (2 104.3 +/- 1 661.8) ng/g in Excoecaria agallocha, (3 197.6 +/- 2 782.8) ng/g in Sonneratia apetala, (817.5 +/- 632.3) ng/g in Acanthus ilicifolius, (1 801.8 +/- 1 255.4) ng/g in Rhizophora. stylosa, respectively. There are obvious interspecific variation, and organic variation in THg contents of mangrove plants, which is closely related to environment and physiological characteristics of mangrove plants. Enrichment of THg in mangrove plants was inhomogeneous, following the order of Sonneratia apetala > Bruguiera gymnorrhiza > Avicennia marina > Aegiceras corniculatum > Excoecaria agallocha > Rhizophora stylosa > Kandelia candel > Acanthus ilicifolius. Mercury exists mainly in volatile form in most mangrove wetlands, but mainly in the form of residue in sediments from Shenzhen mangrove wetlands. Significantly positive correlations were found among Hg concentrations in leaves and stems of Sonneratia apetala and volatile Hg, exchangeable Hg of sediments. Significantly positive correlations were also found among Hg concentrations in leaves of Excoecaria agallocha and volatile Hg, exchangeable Hg of sediments. But, there is no significant correlation between Hg concentrations of most mangrove plants and different Hg speciation in sediments. It showed that plants assimilate Hg from different sources, such as water, sediment and air, and that Hg assimilated by plants could transfer among different plant organics.

[Preliminary study on the distribution and impact factors of methylmercury in surficial sediments from main mangrove wetlands of China].

Total mercury (THg), methylmercury (MeHg) and environmental factors were determined to study distributions of MeHg and Hg methylation in the sediments from 8 main mangrove areas of China. The results showed that it was not consistent for distributions of THg and MeHg in sediments. Concentrations of MeHg in sediments from Sanya, Dongzhaigang (Hainan Province), Techengdao, Leizhou, Gaoqiao, Futian (Guangdong Province), Daguansha (Guangxi Autonomous Region), Fugong (Fujian Province) were (0.24 +/- 0.04), (0.58 +/- 0.27), (0.52 +/- 0.23), (1.56 +/- 0.49), (0.50 +/- 0.25), (1.21 +/- 0.36), (1.86 +/- 1.04), (0.47 +/- 0.16) ng x g(-1) respectively. There were regional difference in MeHg contents which decreased in the order of Daguansha > Leizhou > Futian > Dongzhaigang > Techengdao > Gaoqiao > Fugong > Sanya. Input of Hg and organic matter from industry and aquiculture may lead to high level of MeHg. Compared with sediments from other estuaries of the world, serious pollution of MeHg was found in mangrove sediments of China. (2) % MeHg in mangrove sediments ranged from 0.11% to 7.13%, which decreased in the order of Daguansha > Techengdao > Leizhou > Futian > Gaoqiao > Dongzhaigang > Sanya > Fugong. There was significantly positive correlation between % MeHg and sandy fraction (p < 0.05), and significantly negative correlation between % MeHg and silt-clay fraction (p < 0.05). (3) Total bacteria (TB) in mangrove sediments ranged from 2.44 x 10(10) to 1.91 x 10(11) CFU/g (dry weight), TB decreased in the order of Fugong > Sanya > Gaoqiao > Dongzhaigang > Futian > Daguansha. Sulfate-reducing bacterium (SRB) ranged from 1.73 x 10(4) to 4.92 x 10(6) CFU/g, SRB decreased in the order of Futian > Fugong > Dongzhaigang > Sanya > Gaoqiao > Daguansha. Wastewater with high organic matters leads to high SRB. The types of surface sediments also had a great impact on the amount of SRB. There was no significant correlation among MeHg and environmental factors, which indicated that exogenous input is the main cause of MeHg pollution in mangrove sediments.

[Distribution of mercury in surficial sediments from main mangrove wetlands of China].

Surficial sediment samples were collected from main mangrove wetlands of China, mercury, pH, salinity, organic matters, grain size, Fe/Hg, Mn/Hg were analyzed. Mercury content ranges from 2.3 to 903.6 ng x g(-1), with a average of (197 +/- 137.6) ng x g(-1). Compared with local background level, serious Hg pollution with high Hg content was found in 7 areas, including Luoyangqiao [(467.5 +/- 68.8) ng x g(-1)], Fugong [(438.2 +/- 147.0) ng x g(-1)], Ewan [(264.3 +/- 89.2) ng x g(-1)], Yaojiayu [(125.4 +/- 27.1) ng x g(-1)], Fujian Province; Sanya [(164.8 +/- 143.9) ng x g(-1)], Dongzhaigang [(314.1 +/- 335.7) ng x g(-1)], Hainan Province, Shenzhen [(179.9 +/- 7.7) ng x g(-1)], Guangdong Province. Hg content was similar with background value in the other 6 areas, including Yunxiao [(63.3 +/- 43.9)ng x g(-1)], Fujian Province; Gaoqiao [(178.6 +/- 127.0) ng x g(-1)], Guangdong Province; Daguansha [(26.1 +/- 18.8) ng x g(-1)], Shankou [(73.8 +/- 21.1) ng x g(-1)], Beilun estuary [(117.8 +/- 51.4) ng x g(-1)], Qinzhou Bay [(147.5 +/- 107.6) ng x g(-1)], Guangxi Autonomous Region. Discrepancy of total Hg concentrations in mangrove wetlands is due to many environmental factors and human activities. Parameters such as grain size, pH, organic matter, Fe/Hg, Mn/Hg are significantly correlated with total Hg respectively. Clay and Fe/Hg are obvious factors influencing total Hg concentration. Impact of environmental factors on mercury can be showed by regression equation.

Differential expression profiles of microRNAs in NIH3T3 cells in response to UVB irradiation.

MicroRNAs (miRNAs) are known as a kind of small, noncoding RNA, which play an important role in mediating many biological processes such as development, cell proliferation and differentiation in plants and animals. Here we report the differential expression profiles of miRNAs and characterized putative target genes in NIH3T3 cells at a series of different time points after UVB irradiation (compared with no UVB irradiation). The relative expression of mature miRNA genes was determined by miRNA microarray technique and the results were confirmed by real-time reverse transcriptase polymerase chain reaction (qRT-PCR). Potential target genes of these miRNAs were classified into different function categories with the GOstat software (http://gostat.wehi.edu.au/cgi-bin/goStat.pl). Several miRNAs in this study expressed highly at different time points, especially mmu-miR-365 and mmu-miR-21. Three miRNAs were lowly expressed, of which mmu-miR-465 showed low levels of expression at all time points, whereas after 50 J m(-2) UVB irradiation mmu-miR-296 and mmu-miR-376c showed low levels of expression at 6 and 12 h, respectively. Our study provided a basis for the global characterization of UV-regulated miRNA expression.

[Mechanisms of G2/M cycle arrest induced by topo IIalpha and II beta inhibitors in H460 cells].

OBJECTIVE: To compare the mechanisms of G(2)/M cycle arrest induced by topo IIalpha and IIbeta inhibitors in H460 cells. METHODS: The inhibitory effects of XK469, adriamycin and etoposide on H460 cell growth were analyzed by MTT assay. The changes in cell cycle and expressions of cdc2, phos-cdc2 and 14-3-3sigma proteins induced by these 3 topo II inhibitors were detected by flow cytometry and Western blotting, respectively. RESULTS: Both of the two types of topo II inhibitor resulted in dose-dependent G(2)/M phase arrest and growth inhibition of H460 cells, but XK469 failed to induce 14-3-3sigma protein expression as adriamycin and etoposide did. CONCLUSION: Topo IIalpha and topo IIbeta inhibitors induce growth inhibition of H460 cells possibly through two different mechanisms, namely the 14-3-3sigma-dependent pathway and the 14-3-3sigma-independent pathway, but further functional inhibition test of 14-3-3sigma is needed to confirm this hypothesis.

[Roles of p38 and ERK signaling pathway in cell apoptosis induced by UVB irradiation].

OBJECTIVE: To explore the involvement of p38 and ERK signal transduction pathways in UVB-induced cell apoptosis. METHODS: HaCat cells were exposed to UVB irradiation for 1, 3, 5, 10, and 15 min, respectively, after which the cell survival was assessed using MTT assay, and the cell apoptosis observed under fluorescent microscope with Hoechst staining. Western blotting was used to examine the possible signal transduction pathway involved in the cell apoptosis following the exposures. RESULTS: For the same incubation time following the exposure, the cell survival rate decreased gradually with the increase of UVB irradiation dose. At a fixed UVB irradiation dose, prolonged cell incubation following the exposure resulted in decreased cell survival rate, which, however, began to increase after the minimum rate was reached. At different UVB doses, cell exposure for 5 min caused the highest cell apoptosis rate, which peaked at 12 h during the post-irradiation incubation. The expressions of p38 and p53 were significantly decreased while p44/42 expression remained unchanged in the exposed cells. CONCLUSION: UVB irradiation can induce growth inhibition and apoptosis of HaCat cells in a dose- and time-dependent manner, and p38 pathway other than ERK pathway is probably involved in UVB-induced cell apoptosis.

Downregulation of HBx mRNA in HepG2.2.15 cells by small interfering RNA.

OBJECTIVE: Hepatitis B virus (HBV) infection is one of the most prevalent viral infectious diseases in humans. And it is still a challenge for the development of an effective therapy for HBV infection. Recently, the progress in RNA interference (RNAi) has shed some light on the inhibition of HBV expression and replication by RNAi specific for the various genes of the HBV genome. Some prior researches suggests that the HBV x protein (HBx) plays an important role in viral transcription, cell growth, and apoptotic cell death. METHODS: In the present study, we designed three siRNAs based on the X-protein of HBV sequences and tested their effects on the expression of HBx gene following sorting of siRNA-positive cells. The interference effect was tested in 24, 48, and 72 h. HBsAg in cultured media was assayed using western blot at various days post-transfection. The amount of HBx mRNA was quantitated by Real-time reverse-transcript PCR (RT-PCR). RESULTS: There was a decrease in the levels of HBV mRNA and HBsAg from the the transfected cells. Among these three siRNAs, siRNA-2 was found to be the most effective at suppressing HBV gene expression.

Distribution and ecological effect of mercury in Laogang landfill, Shanghai, China.

Laogang landfill near Shanghai is the largest landfill in China, and receives about 10000 t of daily garbage per day. Samples of topsoil and plants were analyzed to evaluate mercury pollution from the landfill. For topsoil samples, there were significant correlations among total mercury (HgT), combinative mercury (HgC) and gaseous mercury (HgG), and content of total organic carbon (TOC), but, no significantly relationship was found between Hg content and filling time. Hg content changes in vertical profiles with time showed that the average HgT of profiles 1992, 1996, and 2000 was similar, but their average HgG was quite different. HgT was significantly correlated with HgC in profile 1992 and 2000, and HgT was significantly correlated with HgG in profile 1996. HgG/HgT ratio in profile samples decreased in the order of (HgG/HgT)1992 > (HgG/Hg)1996 >> (Hg/HgT)2000. A simple outline of Hg release in landfill could be drawn: with increasing of filling time, degradation undergoes different biodegradation, accordingly, gaseous mercury goes through small, more, and small proportion to total mercury. Distribution of Hg in plants was inhomogeneous, following the order of leaf > root > stem. The highest value of leaf may be associated with higher atmospheric Hg from landfill. Ligneous plants (e.g. Phyllostachys glanca, Prunus salicina and Ligustrum lucidum) are capable of enriching more Hg than herbaceous plants.

[Specific small interfering RNAs inhibit replication of hepatitis B virus].

OBJECTIVE: To obtain specific small interfering RNAs (siRNA) for hepatitis B virus (HBV) and evaluate their interfering effect. METHODS: Three siRNAs were transfected into HepG2.2.15 cells, and the amount of HBV mRNA in the cell culture medium was quantified with real-time fluorescence quantitative RT-PCR. HBsAg in the culture media was assayed with Western blotting at different time points after transfection. RESULTS: The cells transfected with specific siRNAs showed decreased levels of HBV mRNA and HBsAg (P<0.05), but those with nonspecific siRNA transfection as the negative control did not show such changes (P>0.05). CONCLUSION: Specific siRNA can significantly inhibit protein expression and mRNA synthesis of HBV in HepG2.2.15 cells in vitro.

[Positron emission tomography with L-[S-methyl-11C]-methioine and its biodistribution].

OBJECTIVE: To study the biodistribution of L-[S-methyl-(11)C]-methioine ((11)C-MET) and explore its clinical application in positron emission tomography (PET) for brain tumor detection. METHODS: Twenty-four Wistar rats and divided into 6 equal groups and injected with (11)C-MET through the tail vein and killed by decollation at 5, 10, 20, 30 and 40 min after injection, respectively. The liver, brain, blood, heart, lung, kidney, and spleen were harvested to measure the radioactivity and calculate the biodistribution of (11)C-MET. PET imaging with (11)C-MET was performed in 6 normal volunteers and 30 patients with pathologically confirmed brain gliomas. RESULTS AND CONCLUSION: (11)C-MET showed high blood uptake and a long retention in the tumor mass, therefore can be a valuable tracer for PET imaging of brain tumor and the hypophysis.

[Research progress on wetland ecosystem service and its valuation].

With the recognition on the significance of wetland, wetland ecosystem service was come under more and more attention, and its valuation could give the policymakers a scientific support in punishing wetland destroyers and compensating its losers. This paper introduced the definitions of wetland ecosystem service, its function and value, summarized their valuation approaches, including market value approach, production function method, opportunity cost approach, shadow project approach, productivity variety approach, human capital approach, travel cost approach, hedonic value approach, contingent value approach and ecological value approach, and discussed the factors affecting the valuation results of these approaches as well as the existing problems in related researches. The further research directions in these fields were also prospected.

[Advances in the studies of miRNAs and cell apoptosis].

MicroRNAs (miRNAs) are a recently discovered class of 18 - 24 nucleotide RNA molecules that negatively regulate target mRNAs. All studied multicellular eukaryotes utilise miRNAs to regulate basic cellular functions including proliferation, differentiation, and death. In this review, we will discuss the function of miRNAs that regulate cell proliferation and apoptosis. Antiapoptotic miRNAs include the miRNAs of the miR-17 cluster, miR-21, bantam and miR-14, Proapoptotic miRNAs include let-7, miR-15a and miR-16.

[Effect factors for mercury accumulation to natural surface coatings and analysis its forms of occurrence].

In order to probe to the factors for mercury accumulation to natural surface coating, we study the concentration of mercury in Huangpu River surface coatings developed for different depth, different grown days and different seasons and analysis mercury forms of occurrence. The result show the organic matter in biofilm is much high (7.5%-14.5%). Growth time, depth and seasons are all important factors for mercury accumulation to surface coating. Illumination and temperature was stronger and the growth day was longer, The concentration of mercury in biofilm was higher. The mercury forms of occurrence in surface coating were mainly residual matter bound mercury (41.98%) and organic acids bound mercury (27.89%). The percentage of carbonate bound mercury (10.17%) and ion exchangeable mercury (5.33%) was little.

[Changes in immune function of dendritic cells infected by recombinant adenovirus containing Her2/neu gene of extracellular and transmembrane domain proteins].

OBJECTIVE: To observe the functional changes of dendritic cells (DCs) infected in vitro by 3 recombinant adenoviruses encoding Her2/neu extracellular first-receptor domain (Her2-ECDs), full-length extracellular domain (Her2-ECD), and extracellular and transmembrane domain (Her2-TM) proteins (rAdHer2-ECDs, rAdHer2-ECD and rAdHer2-TM, respectively). METHODS: The expressions of the target proteins were detected with Western blotting. The level of both interleukin (IL)-12 in the supernatant of in vitro cultured DCs infected with recombined adenoviruses and interferon gamma (IFN-gamma) in the supernatant of the lymphocyte populations co-cultured with DCs were determined by enzyme-linked immunosorbent assay (ELISA). The capacity of the DCs to stimulate allogeneic T lymphocyte proliferation was assessed by mixed lymphocyte reaction, and the activity of cellular toxic T lymphocytes (CTL) were investigated by MTT assay. RESULTS: Her2-ECDs, ECD and TM proteins were detected in the transfected DCs. Compared with the untransfected DCs, more abundant IL-12 production was detected in the supernatant of the DCs 5 days after transfection, but the IL-12 level showed no significant difference between the DCs infected with the 3 recombinant adenoviruses. IFN-gamma production increased gradually with passage of the time following DC-stimulated lymphocyte proliferation irrespective of infection of the DCs, and only the DCs infected with rAdHer2-TM seemed to result in significant difference in DC-mediated allogeneic T lymphocyte proliferation. The killing of breast cancer cell line with Her2 overexpression was more efficient with infected DCs priming autologous T lymphocyte to generate CTL than with uninfected DCs and those modified by SK-OV-3 cell fragment. CTL activity induced by rAdHer2-TM-infected DCs was the strongest, and breast cancer cell-killing activity was more efficient against cell line with Her2/neu-overexpression. CONCLUSION: The DCs infected with the recombinant adenovirus encoding Her2/neu extracellular and transmembrane domains show enhanced anti-tumor effect and induce Her2/neu-specific CTL activity.