Expressions of EZH2 and DLC1 in breast cancer tissues and cell lines and their correlation / 肿瘤

Objective: To study the expressions of enhancer of zeste homolog 2 (EZH2) and deleted in liver cancer-1 (DLC1) in breast cancer tissues and cell lines, and to explore their relationship. Methods: The expressions of EZH2 and DLC1 proteins in 120 cases of breast cancer tissues and 63 cases of para-cancerous tissues were detected by immunohistochemistry. The expression levels of EZH2 and DLC1 mRNAs and proteins in 20 cases of breast cancer tissues, 20 cases of the corresponding para-cancerous tissues, breast cancer MCF-7 and MDA-MB-231 cells and the normal mammary epithelial HBL100 cells were detected by real-time fluorescent quantitative PCR and Western blotting, respectively. The specific siRNA targeting EZH2 gene was transfected into MDA-MB-231 cells by liposome, then the expression levels of EZH2 and DLC1 mRNAs and proteins in MDA-MB-231 cells were detected again by realtime fluorescent quantitative PCR and Western blotting, respectively. Results: The positive expression rate of EZH2 in breast cancer tissues was significantly higher than that in corresponding para-cancerous tissues (P = 0.000). The positive expression rate of DLC1 in breast cancer tissues was significantly lower than that in corresponding para-cancerous tissues (P = 0.008). The expression rates of EZH2 and DLC1 were significantly correlated with tumor size and lymph node metastasis (both P < 0.05). The expression levels of EZH2 mRNA and protein in breast cancer tissues and breast cancer MCF7 and MDA-MB-231 cells were signifiicantly higher than those in corresponding para-cancerous tissues and normal breast epithelial HBL100 cells (all P < 0.01), but the expression levels of DLC1 mRNA and protein were lower than those in corresponding para-cancerous tissues and normal breast epithelial HBL100 cells (all P < 0.01). After EZH2 gene-silencing, the expression levels of DLC1 mRNA and protein in MDA-MB-231 cells were increased (both P < 0.05). Conclusion: There is a negative correlation between the expressions of EZH2 and DLC1 in breast cancer, and the inhibition of EZH2 expression can restore the expression of DLC1; which suggests that EZH2 maybe promote the occurrence and development of tumor by inhibiting the expression of DLC1.

Expressions and clinical significances of DLC-1 and ROCKⅠin non-small cell lung cancer / 国际肿瘤学杂志

Objective To explore the expressions and clinical significances of deleted in liver cancer-1 (DLC-1 ) and Rho associated coiledcoil forming protein kinase (ROCK )Ⅰ in non-small lung cancer (NSCLC).Methods The expressions of DLC-1 and ROCKⅠ in NSCLC and adjacent tissue of 48 patients with pathologically confirmed as NSCLC and undergone surgical resection were detected by immunohistochemis-try EnVision method.The correlations among DLC-1 protein,ROCKⅠ protein and the clinical pathological characteristics were analyzed.The prognostic value of DLC-1 in patients with NSCLC was studied.Results The expression of DLC-1 protein in NSCLC tissue was low or missing,and the positive rate was 33.3%(16/48),significantly lower than that in the tissue adjacent to carcinoma 70.8% (34/48),with statistical significance (χ2 =13.523,P<0.01).The positive expression rate of ROCKⅠprotein in NSCLC was 58.3%(28/48),higher than that of tissue adjacent to carcinoma 0(0/48),with statistical significance (χ2 =39.529, P<0.01).The expression of DLC-1 protein was correlated with tumor differentiation,lymph node metastasis and clinical stage,rather than with sex,smoking history and organization type.Through the correlation analy-sis,the expression of ROCKⅠin DLC-1 positive group was 37.5%(6/16),and the expression rate of ROCKⅠ in DLC-1 negative group was 68.8%(22/32).There was negative correlation between DLC-1 and ROCKⅠin NSCLC tissues (r=-2.214,P=0.039).The 3 year survival rate in DLC-1 protein high expression group was obviously higher than that in low expression group,with statistical significance (P=0.043).Conclusion Low or missing expression of DLC-1 and high expression of ROCKⅠ protein may play an important role in the occurrence and development of NSCLC.Detecting the expression of DLC-1 and ROCKⅠprotein may be useful for evaluating the biological behavior and prognosis of NSCLC.

Expression of DLC1 mRNA and protein in breast carcinoma and non-cancerous breast tissues and its relationship with Ki-67 / 临床与实验病理学杂志

Purpose To investigate the expression of DLC1 and its relationship with Ki-67 in cancerous and non-cancerous tissues of the breast.Methods In situ hybridization and immunohistochemiscal EnVision method were used to detect the expression of DLC1 mRNA and protein and Ki-67 in 52 invasive breast ductal carcinomas and 42 non-cancerous mammary tissues, including 22 mammary fibroadenomas and 20 paracancerous tissues.Results The positive rates of DLC1 mRNA and protein expression in the breast carcinomas (50% and 57.7%) was significantly lower than that in the non-cancerous mammary tissues (90.5% and 92.9%) (χ~2=17.518 and 10.729,P＜0.01).The expression of DLC1-mRNA was positively related to DLC1protein (r_s=0.379,P＜0.01). The positive rate of Ki-67 expression was 61.5% in the breast carcinomas, but no expression was observed in the all non-cancerous tissues (χ~2=39.186,P＜0.01).Correlation analysis showed that DLC1 expression was negatively correlated with Ki-67 expression (r_s=-0.507,P＜0.01).Conclusions Lower or no expression of DLC1 mRNA and protein may play an important role in the pathogenesis and progression in breast carcinoma. DLC1 may inhibit the proliferation of the breast carcinoma cells,which indicates that it may act as a new molecular marker of breast carcinoma.Combining detection of DLC1 and Ki-67 may be useful parameters for evaluating the biological behaviors of breast carcinoma.

Transcriptional induction of DLC-1 gene through Sp1 sites by histone deacetylase inhibitors in gastric cancer cells

We previously reported that trichostatin A (TSA), a histone deacetylase (HDAC) inhibitor, induced DLC-1 mRNA expression and accumulated acetylated histones H3 and H4 associated with the DLC-1 promoter in DLC-1 non-expressing gastric cancer cells. In this study, we demonstrated the molecular mechanisms by which TSA induced the DLC-1 gene expression. Treatment of the gastric cancer cells with TSA activates the DLC-1 promoter activity through Sp1 sites located at -219 and -174 relative to the transcription start site. Electrophoretic mobility-shift assay (EMSA) revealed that Sp1 and Sp3 specifically interact with these Sp1 sites and showed that TSA did not change their binding activities. The ectopic expression of Sp1, but not Sp3, enhances the DLC-1 promoter responsiveness by TSA. Furthermore, the TSA-induced DLC-1 promoter activity was increased by p300 expression and reduced by knockdown of p300. These results demonstrated the requirement of specific Sp1 sites and dependence of Sp1 and p300 for TSA-mediated activation of DLC-1 promoter.

Effects of DNMT3b on expression and methylation status of promoter region of DLC-I in human hepatocellular carcinoma cell line / 中华肝胆外科杂志

Objective To explore the effects of DNMT3b on the expression and methylation sta-tus of the promoter region of DLC-1 in human hepatocellular carcinoma cell line. Methods The SMMC-7721 cell line was divided into 2 groups. The cell line in the experimental group was transfect-ed with DNMT3b siRNA, while that in the control group was transfected with control siRNA. West-ern blot was used to detect the expression of DNMT3b and DLC-1 and MSP was employed to examine the methylation status of the promoter region of DLC-1. Results The expression of DNMT3b was significantly higher in the experimental group than in the control group, while the expression of DLC-1 was just opposite. There was no significant difference in the methylation status of the promoter re-gion of DLC-1 between the 2 groups and both were methylated. Conelnsion The inhibition of expression of DNMT3b by siRNA method can enhance the expression level of DLC-1, and the methylation status of the promoter region of DLC-1 does not change at the same time. When affecting the expression of DLC-1, DN-MT3b might not play the role of methyhransferase, but can act as a transcriptional regulatory factor.