Distribution and Interactive Effects of Heavy Metals in Soil-Maize (Zea Mays L.) System in the Mercury Mining Area, Southwestern China.

The concentrations and interactive effects of beneficial elements (i.e., Se, Mo, and Zn) and heavy metals (As, Cd, Hg, and Pb) of maize (Zea mays L.) grown on lime soil and/or soil with mercury tailing were investigated in this study. The results show that the concentrations of heavy metals (i.e., As, Hg, and Pb) in soil with tailing were higher than those in lime soil. The concentrations of beneficial elements (i.e., Mo and Zn) in maize grown on soil with tailing were higher than those of maize grown on lime soil. The mean concentrations of Se, Mo, and Zn in maize grown on soil with tailing were 3.67 mg/kg, 0.530 mg/kg, and 27.4 mg/kg. The pH and an antagonistic effect played an important role in the concentrations of Mo and Zn in maize. The Se concentration in maize was controlled by the planting media.

Identification of CXCL10 as a Prognostic Biomarker for Clear Cell Renal Cell Carcinoma.

Background: One of the widespread forms of kidney tumor is clear cell renal cell carcinoma (ccRCC), with poor prognosis and insensitivity to radio chemotherapy as there is limited capacity to understand the disease mechanism. This study aims at identifying potential biomarkers and the underlying processes of ccRCC using bioinformatics analysis. Methods: Transcriptome data of relevant samples were downloaded from The Cancer Genome Atlas (TCGA) database. R software was used to screen differentially expressed genes (DEGs) using the "edgeR" package. Two types of analysis-Gene Ontology (GO) functional and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment-were accomplished by applying Database for Annotation, Visualization, and Integrated Discovery (DAVID) and Search Tool for the Retrieval of Interacting Genes database (STRING) online bioinformatics tools. A protein-protein interaction (PPI) network of the identified DEGs was constructed using Cytoscape software, and hub genes were subsequently selected via the Cytohubba plug-in. The selected genes were input into Oncomine for verification. Finally, selected hub genes were analyzed by doing survival analysis to notice the relationship between survival (OS) rate and the selected genes' level of expression. Results: There were 1,855 DEGs found connected to ccRCC, with 1,207 upregulated genes and 648 downregulated genes. G-protein-coupled receptor signaling pathway, integral component of membrane, calcium ion binding, and cytokine-cytokine receptor interaction were among the DEGs discovered. Oncomine confirmed the top six hub genes from the PPI network (C3, CXCR3, CXCL10, CCR5, CCL4, and CCL5). A high level of expression of CXCL10, one of these hub genes, was linked to a poor prognosis in individuals with ccRCC. The results of survival analysis showed that the expression level of CXCL10 was significantly correlated with the prognosis of ccRCC patients (p < 0.05). Conclusions: From the analysis, the following results were drawn: CXCL10 might be a potential prognostic biomarker and novel therapeutic target for ccRCC.

Mitogen-activated protein kinase mediates the apoptosis of highly metastatic human non-small cell lung cancer cells induced by isothiocyanates.

Dietary isothiocyanates have been shown to possess anti-tumour activity, inhibiting several types of cultured human cancer cell growth. However, there are limited studies on their effects on cancer cell metastasis. Our previous study showed that benzyl isothiocyanate (BITC) and phenethyl isothiocyanate (PEITC) suppressed human lung cancer cell metastasis potential. In the present study, we found BITC (7·5 and 10 µm) and PEITC (12·5 and 20 µm) induced highly metastatic human non-small cell lung cancer L9981 cell apoptosis in a dose-dependent manner. Caspase-3 was activated. They also caused cell cycle arrest at the G2/M phase, via modulation of cyclin B1 expression. The mitogen-activated protein kinase (MAPK) signalling pathway was involved. c-Jun N-terminal kinase, extracellular signal-regulated protein kinase 1/2 and p38 were activated in a dose-dependent manner; activator protein 1 (AP-1) transcriptional activation and cyclin D1 expression were repressed. Apoptosis and MAPK activation were abrogated by anti-oxidant N-acetyl cysteine (NAC), suggesting that cell death signalling was triggered by oxidative stress. Further microarray analysis evaluated the potential targeted genes related to apoptosis and the cell cycle. Our studies suggested that BITC and PEITC suppressed the metastasis potential of highly metastatic lung cancer cells by inducing apoptosis and cell cycle arrest, via targeting the MAPK/AP-1 pathway. This may provide a novel approach for metastasis therapy of lung cancer by dietary isothiocyanates and possibly other types of cancer.

Isothiocyanates induce oxidative stress and suppress the metastasis potential of human non-small cell lung cancer cells.

BACKGROUND: Isothiocyanates are natural compounds found in consumable cruciferous vegetables. They have been shown to inhibit chemical carcinogenesis by a wide variety of chemical carcinogens in animal models. Recent studies have also shown that isothiocyanates have antitumor activity, inhibiting the growth of several types of cultured human cancer cells. Our previous study showed that PEITC inhibited human leukemia cells growth by inducing apoptosis. However, the effect of isothiocyanates on lung cancer cell metastasis has not been studied. In the present study, we investigated the inhibitory effects of BITC and PEITC on metastatic potential of highly metastatic human lung cancer L9981 cells. METHODS: Cell migration and invasion were measured by wound healing assay and transwell chemotaxis assay. Expression of metastasis-related genes was assessed by quantitative RT-PCR and Western blotting. The mechanisms of action were evaluated by flow cytometry, reporter assay and Western blotting. RESULTS: Our data showed that both BITC and PEITC inhibited L9981 cell growth in a dose-dependent manner, the IC50 values were 5.0 and 9.7 microM, respectively. Cell migrations were reduced to 8.1% and 16.5% of control, respectively; and cell invasions were reduced to 2.7% and 7.3% of control, respectively. Metastasis-related genes MMP-2, Twist and beta-catenin were also modulated. BITC and PEITC inhibited cell survival signaling molecules Akt and NFkappaB activation. Moreover, BITC and PEITC increased ROS generation and caused GSH depletion. Pretreatment with NAC blocked BITC and PEITC induced ROS elevation and NFkappaB inhibition. CONCLUSION: Our results indicated that BITC and PEITC suppress lung cancer cell metastasis potential by modulation of metastasis-related gene expression, inhibition of Akt/NFkappaB pathway. Induction of oxidative stress may play an important role.

The relationship between methylation of the Syk gene in the promoter region and the genesis of lung cancer.

BACKGROUND: To study the expression of the Syk (Spleen Tyrosine Kinase) gene and methylation in its promoter region in lung cancer. To investigate the relationship between silencing of the Syk gene and DNA methylation of the Syk promoter region. METHODS: RT-PCR (Semi-quantitative reverse transcription PCR), Real-time PCR (Real-time quantitative PCR) and immunohistochemistry technique, the expression of Syk in specimens from 3 lung cancer cell lines and 16 lung cancer patients (tumor tissues and adjacent normal tissues). MSP (Methylation-specific PCR) was used to analyze the methylation status of the Syk promoter region. Then we also investigated the role of restoring Syk expression by using a DNA methyltransferase inhibitor, 5-aza-CdR (5-aza-2'-deoxycytidine), in suppressing invasion of lung cell lines. RESULTS: No expression of the Syk gene was detected in the 3 lung cancer cell lines. In the 16 lung patient samples, Syk expression was significantly lower in the tumor tissues than in the adjacent normal tissues (P < 0.05). Consistently, immunohistochemistry analyses of Syk protein expression showed that in the cancer tissues Syk protein expression accounted for 5% (1/20), and in the adjacent normal tissues the rate of expression was 100% (20/20). The correlation was highly significant (chi2 = 36.19, P < 0.005). In the only case that showed a positive expression of cancer textus, the level was inferior to the adjacent tissue. In the two lung cancer cell lines (L9981, A549) that lack the endogenous Syk epression, 4uM demethylation agent 5-aza-CdR treatment was able to reactivate the Syk gene expression. CONCLUSIONS: Hypermethylation leads to silencing of the Syk gene in human lung carcinoma. Methylation of the Syk promoter and loss of Syk expression in lung cancer are independent biomarkers, a determination which may offer guidance for selecting appropriate diagnoses and treatments. Syk may be a potential tumor suppressor in human lung cancer.

[Construction and screening of the subtracted cDNA library of human large cell lung cancer lines with different metastatic potentials].

BACKGROUND: Screening metastatic-related genes of lung cancer is helpful to understand the molecular mechanisms of lung cancer invasion and metastasis. In order to screen the differential expression genes related to metastasis of lung cancer, we constructed and preliminarily screened the subtracted cDNA libraries of human large cell lung cancer cell lines with different metastatic potentials in this study. METHODS: Subtracted cDNA library was constructed in the different metastastic potential cell lines NL9980 and L9981 by suppression subtractive hybridization (SSH) method. The positive clones were preliminarily screened by blue-white colony based on the α-complementary principal, and precisely identified by PCR. The forward and reverse subtracted libraries were screened and identified by dot blot to obtain the clones corresponding to differential expression segments. RESULTS: The subtracted cDNA libraries were successfully constructed in the different metastastic potential cell lines NL9980 and L9981. Three hundred and seven positive clones in the forward subtracted library and 78 positive clones in the reverse subtracted library were obtained by the dot blot method. CONCLUSIONS: SSH is proved to be an efficient tool for differential expression gene cloning. The forward and reverse subtracted cDNA libraries of different metastastic potential cell lines are constructed by this method. The differential expression genes related to tumor metastasis might exist in the human large cell lung cancer cell lines with different metastasis potential.

[Quantitative detection of GSTP1 gene sin the lung tissue of hypobaric hypoxia modeling rats].

We have investigated the susceptibility of rat lung's GSTP1 gene to hypobaric hypoxia and explored its role in the body's possible adaptation mechanism at the moleuclar lever. Thirty male SD rats were randomly divided into five groups(0,1,3,5 and 7 d) and were exposed for 12 h per day at a simulating altitude of 7000 +/- 50 m in a hypobaric hypoxia chamber with 1 h's rest after 6 h's exposure. Then the expression of GSTP1 mRNA in the lung tissue of SD rats was examined using fluorescence quantitative RT-PCR. Meanwhile the activity of glutathione S-transferases (GSTs) enzyme and the change of maleic dialdehyde (MDA) in the lung tissue of SD rats were determined using spectrophotometer. In comparison with the non-exposure group,the expression of GSTP1 gene showed statistically significant differnce from the first to the seventh day (P<0.05). The level of GSTs decreased and MDA increased from the first to the seventh day (P<0.05). In conclusion, GSTP1 gene is susceptible to hypobaric hypoxia and may be a new marker of gene screening for the body's adaptation to special environment.

AG1478 inhibits the migration and invasion of cisplatin-resistant human lung adenocarcinoma cells via the cell cycle regulation by matrix metalloproteinase-9.

AG1478 is a specific epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor. The effect of AG1478 on the A549/DDP (cisplatin-resistant human lung adenocarcinoma) cell line is unknown. The aim of the present study was to investigate the effects of AG1478 on the A549/DDP cell line and its sensitive parental A549 cell line. The two cell lines were treated with AG1478 and the growth, proliferation, migration and invasion of the tumor cell lines were measured using flow cytometry, as well as 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide, wound healing and Transwell system assays. The expression of metastasis-associated genes and proteins was evaluated by quantitative-polymerase chain reaction and western blot analysis. The molecular mechanisms were investigated using short-interfering RNAs (siRNAs). The phosphorylation status of the key cell cycle protein, retinoblastoma (Rb), was also investigated. The results revealed that AG1478 inhibited the growth of the two cell lines with varying potency, and that the A549/DDP cell line was more sensitive to AG1478 than the A549 cell line. Cell migration and invasion, as well as matrix metalloproteinase (MMP)-9 and E2F1 expression were significantly inhibited. However, MMP-9 expression was also significantly suppressed in the two cell lines following transfection with E2F1-targeting siRNA. In addition, AG1478 significantly arrested A549/DDP and A549 cells in G1 phase, with a corresponding reduction in the S phase. The phosphorylation of Rb protein at various sites was selectively inhibited by AG1478 at various time points. The results indicate that AG1478 may provide a clinical therapeutic approach for certain types of cisplatin-resistant lung cancer.

[Influence of MSA on cell growth and spontaneousn metastasis of L9981-Luc lung cancer transplanted model in nude mice by bioluminescence imaging].

BACKGROUND AND OBJECTIVE: Methylseleninic acid (MSA) is an artificially developed selenium compound. It has been proven that MSA could inhibit growth and metastasis on many tumor cells. This study investigated whether MSA has an impact on the growth and metastasis of L9981-Luc lung cancer transplanted model in nude mice or not. METHODS: A transplantated tumor model was established in nude mice. Fifteen nude mice were randomly divided into three groups: the control group treated with normal saline (0.2 mL/d), the MSA group treated with MSA solution (0.2 mL), and the cisplatin (DDP) group injected intraperitoneally with DDP (4 mg/kg/w). Inhibition of MSA on tumor growth and tumor metastasis was observed using the IVIS Imaging System 200 Series. RESULTS: A significant difference was obserced in the primary tumor bioluminescence among the three groups (P=0.002) on 21 days post-inoculation. Primary tumor bioluminescence in the DDP group (P=0.001) and in the MSA group (P=0.031) was significantly lower than that in the control group (P=0.001). No significant difference in the metastasis bioluminescence of the thoracic area was indicated among the three groups (P>0.05). CONCLUSIONS: MSA can inhibit the growth of planted tumor of transgenic lung cancer cell lines L9981-Luc in nude mice. MSA may also suppress the distant metastasis of the transplanted tumor of transgenic lung cancer cell lines L9981-Luc in nude mice.

Apoptosis induced by benzyl isothiocyanate in gefitinib-resistant lung cancer cells is associated with Akt/MAPK pathways and generation of reactive oxygen species.

Gefitinib is the first targeted drug approved for non-small cell lung cancer (NSCLC) treatment. Clinical trails showed that patients with certain clinical and histologic characteristics (such as women, patients of East Asian descent, no history of smoking, and adenocarcinoma) had higher rates of response and overall survival. Despite excellent clinical response to gefitinib in certain NSCLC patients, nearly all patients who respond initially to gefitinib later develop drug resistance. Isothiocyanates have been shown to possess antitumor activity, inhibiting several types of cancer cells growth. However, there are limited studies on their effects on chemoresistance of cancer cells. In this report, we found that benzyl isothiocyanate (BITC) inhibited gefitinib-resistant human NSCLC cells growth by inducing apoptosis in a dose-dependent manner, and activated caspase-3. There were no effects of BITC on epidermal growth factor receptor and multidrug resistant proteins expression. BITC caused cell cycle arrest at G2/M phase, reactive oxygen species generation, and glutathione depletion. Akt activity and NFκB transcriptional activation were suppressed; mitogen-activated protein kinase and activator protein 1 (AP-1) were activated. Our results demonstrated that BITC overcame gefitinib resistance in lung cancer cells. The further understanding of the anti-resistance mechanism of BITC would contribute to establish it as a potent lead compound for the synthesis of novel anticancer drugs.

[The influence of in awake and sleeping to the thresholds of ASSR].

OBJECTIVE: To explore the difference of the threshold of auditory steady-state evoked responses (ASSR) in awake and sleeping. METHOD: Fifteen adults (30 ears) with normal hearing were selected to ASSR test. ASSR parameters: carrier frequency (CM)are 0.5, 1.0, 2.0, 3.0, 4.0, 6.0 kHz, modulation frequency (FM) are 46.81 Hz. The test was performed in two different status (in awake and sleeping). RESULT: In awake, the thresholds of ASSR with FM of 46 Hz are significantly lower than 81 Hz (P < 0.01); In sleeping, the thresholds of ASSR with FM of 81 Hz are lower than 46 Hz above 2 kHz CM (P < 0.05), which thresholds were close to pure tone. CONCLUSION: To select low modulate (46 Hz) frequency in awake, and use high modulate (81 Hz) frequency in sleeping. When perform ASSR test, the test values are closer to the actual hearing threshold.

[Methylation profile difference in human high-metastatic large cell lung cancer cell line L9981 and low-metastatic large cell lung cancer line NL9980].

BACKGROUND AND OBJECTIVE: Invasion and metastasis is one of malignant phenotype of lung cancer and the important cause of the death of lung cancer patients. The aim of this study is to explore the methylation profile difference in different metastatic potential cell lines. METHODS: To compare the DNA methylation profile of two large cell lung cancer cell lines with different metastatic potential by MeIP chip hybridization, hypermethylated and hypomethylated genes of L9981 cell lines were analyzed online in NIH-DAVID, KEGG and MILANO webside. RESULTS: Compared with NL9980 cell line, 735 genes are hypermethylated in L9981, including 656 known genes and 79 unknown genes; 809 gene are hypermethylated in L9981, including 698 known genes and 111 unknown genes; the different genes are involved in cell process, signal transduction, cell communication, cell adhesion, cell motility, and angiogenesis. CONCLUSION: Hypermethylation of suppressor genes and negative regulator of signal transduction and hopomethylation of oncogene and cell adhesion molecules (CAMs) in L9981 may promote metastasis of tumor cells.

[The study of the tumorigenicity and metastasis ability in human lung cancer cell line L9981 using in vivo imaging.].

BACKGROUND: The aim of this work is to study the tumorigenicity and metastasis ability in human large cell lung caner cell line L9981 by in vivo imaging. METHODS: We firstly transfected the plasmids with firefly luciferase (luc ) gene into L9981 cells and then established the stable transfected L9981-luc cell line with G418. Then the positive L9981-Lue cells were implanted subcutaneously into mice and were monitored for tumor growth and micrometastases with in vivo imaging technique. RESULTS: The results showed that the bioluminescence density of the stable transfected L9981-Lue cells correlated to the numbers of the tumor cells in vitro . The L9981-Luc cells still keep the high metastasis characterization. After the L9981-Luc cells were implanted into mice subcutaneously for several weeks, we found the metastasis lesions in the different organs of the mice using in vivo imaging machine and the bioluminescence of the tumor correlated with its size. Furthermore, we confirmed the metastasis lesions by scarifying the mice and analyzing with pathological staining. CONCLUSIONS: We established a stable L9981-Luc cell line with high metastasis character that can be used to analyze the tumor invasion ad metastasis in animal model by in vivo imaging.

[A study on the relationship between glutathione S-transferases gene polymorphism and susceptibility response to hypoxia].

AIM: To investigate the relationship between glutathione S-transferases gene polymorphism and susceptibility response to hypoxia. METHODS: In the case-control study, the gene polymorphisms of glutathione S-transferases were tested in Tibetan mountaineers and sea-level Han Chinese by multiple-PCR and PCR-RELP. RESULTS: The frequency of GSTT1 null genotype was significant different between Tibetan mountaineers and sea-level Han Chinese (P < 0.05), OR = 1.86 (95% CI = 1.01-3.39), and also for GSTP(1-105) mutant genotype in two groups (P < 0.01), OR = 2.19 (95% CI = 1.16-4.13). There was significant difference between A allele and G allele of GSTP(1-105) groups (P < 0.01). There was no difference for GSTM1 null genotype between two groups (P > 0.05), OR = 0.78 (95% CI = 0.43 - 1.42). CONCLUSION: GSTT1 and GSTP(1-105) genotype may be associated with susceptibility response to altitude hypoxia.