ABSTRACT
Objective To explore the expression of methyl CpG binding protein 2 (MeCP2) in gastric cancer tissues and its role in multi-drug resistance (MDR) in gastric cancer cells.Methods The expression of MeCP2 in 90 gastric cancer tissues and the adjacent normal tissues was detected by immunohistochemistry,and the relationship between MeCP2 expression level and clinicopathological parameters was analyzed.The expression level of MeCP2 in gastric cancer cell line SGC7901,MDR cell variants SGC7901/doxorubicin hydrochloride(ADR) and SGC7901/vincristine(VCR)was determined by Western blot.After the expression of MeCP2 was silenced by short interference RNA (siRNA),half inhibitory concentration (IC50) of 5-fluorouraeil and cisplatin in gastric cancer cell was tested by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-tetrazolium bromide(MTT) assay.The t test or chi square test was performed for statistical analysis.Results The positive rate of MeCP2 expression in gastric cancer tissues was 72.2％ (65/90),which was significantly lower than that in adjacent normal tissues (93.3％,84/ 90),and the difference was statistically significant (x2 =14.068,P＜0.01).MeCP2 expression was not correlated with age,tumor maximum diameter and lymph node metastasis (all P＞0.05),however which was related to gender,clinical TNM stages and distant metastasis (x2=4.680,4.186 and 4.327;aH P＜ 0.05).The gray scale ratios of MeCP2/β-actin in SGC7901/ADR and SGC7901/VCR were 0.593 7 ± 0.030 5 and 0.651 2 ± 0.018 6,which were lower than that of parental SGC7901 cells (1),and the differences were statistically significant (t =23.080,17.360;both P ＜ 0.01).After the expression of MeCP2 was silenced by siRNA,the IC50 of 5-fluorouracil and cisplatin in SGC7901 transfected with MeCP2 specific siRNA were (11.540 0±0.469 3) μg/mL and (2.273 0±0.265 4) μg/mL,which were higher than the IC50 of 5-fluorouracil and cisplatin in SGC7901 transfected with non-related oligonucleotide sequence ((8.663 0±0.160 1) μg/mL and (0.884 0 ±0.038 6) μg/mL),respectively.The differences were statistically significant (t =15.380 and 8.153;both P ＜ 0.01).Conclusions The expression of MeCP2 in gastric cancer tissues significantly decreased,which was correlated with clinical stages,distant metastasis.MeCP2 can inhibit the MDR of gastric cancer cell,which indicated the dysregulated expression of MeCP2 might participate in the genesis and development of gastric cancer.
ABSTRACT
The expression changes of genes associated with adipose metabolism and regulation of cell growth in backfat tissue at five growth stages (1, 2, 3, 4 and 5 months) of Landrace (a leaner Western breed) and Taihu pigs (a fatty indigenous Chinese breed) were measured by using pathway-focused Oligo microarray. The comparative results between two pig breeds of change ratios showed that the fold changes of 10, 6, 11, 8 and 19 genes were over two times at same month from 1 to 5 months respectively. Variance analysis (ANOVA) revealed that 25 genes in Landrace pigs showed significantly altered in expression among five growth stages (P < 0.05). Principal components analysis (PCA) revealed that angiopoietin-like 4 (ANGPTL4), cathepsin K (CTSK), isocitrate dehydrogenase 2(NADP+) (IDH2), lipoprotein lipase (LPL), malic enzyme 1 (ME1), stearoyl-CoA desaturase (SCD) and uncoupling protein 2 (UCP2) displayed distinctive expression patterns from other genes, which suggested that these genes may be subject to special regulation during the period from 1 to 5 months. K-means clustering analysis revealed that genes in Landrace pigs which showed up-regulation were mainly related to the positive regulation of fatty acid metabolism and genes in Taihu pigs which showed slight fluctuation were mainly related to the regulation of cell growth. Quantitative real-time RT-PCR was used to verify the microarray data for five modulated genes, and a good positive correlation between the two measures of expression was observed for both two pig breeds at different growth stages. These results highlight some possible candidate genes for porcine carcass and meat quality traits, reveal the expressional disciplinarian of correlative genes and provide some data on which to base further study of the dynamic balance process for fatty acid biogynthesis and hydrolyzation.