ABSTRACT
The effects of RNAi-mediated gene silencing of LRlG1 on proliferation and invasion of the human glioma cell line U251-MG and the possible mechanisms were explored in this study. The plasmids pGenesil2-LRIG1-shRNA1 and pGenesil2-LRIG1-shRNA2 were transfected into U251-MG glioma cells respectively by using Lipofectamine 2000 and the transfected cells in which the LRIG1 expression was stably suppressed were selected by G418. The cells transfected with negative shRNA served as control. The expression levels of LRIG1 mRNA and protein were measured by qRT-PCR and Western blotting, respectively. The cell cycle was analyzed by flow cytometry. The results showed that LRIG1 mRNA expression was reduced by 70% and 58% and LRIG1 protein expression by 58% and 26% in U251-MG cells transfected with pGenesil2-LRIG1-shRNAl and pGenesil2-LRIG1-shRNA2 relative to the negative shRNA-transfected U251-MG cells. The proliferative capacity of the LRIG1 specific siRNA-transfected cells was stronger than that of control cells. Cell cycle analysis showed that silencing LRIG1 significantly increased the percentage of S phase cells and the proliferation index (P<0.01). Moreover, silencing LRIG1 could promote the invasion of U251-MG cells (P<0.05). These findings suggested that LRIG1-targeting siRNA can exert a dramatically inhibitory effect on RNA transcription and protein expression of LRIG1, and LRIG1 down-regulation could promote the proliferation of U251-MG cells, arrest U251-MG cells in S phase, and enhance the invasion of U251-MG cells.
ABSTRACT
BACKGROUND: Leucine-rich repeats and immunoglobulin-like domains 1 (LRIG1) gene showed low expression in glioma cells. LRIG1 gene overexpression significantly enhanced LRIG1 mRNA and protein expression and inhibited its biological behavior. However, very few researchs are reported from the stand-point of inhibition of LRIG1 gene expression. OBJECTIVE: To construct specific RNA interference plasmids for LRIG1, establish stably transfected human glioma GL15 cell line, and observe its effect on expression of target gene LRIG1. METHODS: Designed and synthesized two shRNAs (named LRIG1-shRNA1 and LRIG1-shRNA2) specific for LRIG1 mRNA according to the GenBank, and one scrambled shRNA sequence as negative control, named pGenesil2-negative shRNA. The shRNA was inserted into pGenesil2 vector and sequenced. The recombinant vectors were transformed into E. coli. Picked up the positive clones and extracted the plasmids, which were transfected into GL15 cells by Metafectine. G418 was applied to select the stably transfected cell clones. Western Blotting was performed to examine the LRIG1 protein level.RESULTS AND CONCLUSION: The recombinant plasmids which contain shRNA were analyzed by restriction endonuclease digestion and DNA sequence, and it was proved that the fragment was inserted into the expected sites. Compared with the negative control group, the level of LRIG1 protein expression in pGenesil2-LRIG1-shRNA1(LRIG11) transfected cells and in pGenesil2-LRIG1-shRNA2(LRIG12) transfected cells was decreased by 47.9% (P 0.05). The results confirmed that RNAi expressing vector specific for LRIG1 gene (pGenesil2-LRIG1-shRNA1) was successfully constructed, and the stable cell clones transfected with the shRNA expression vector showed inhibition of the expression of LRIG1 in glioma cell line GL15.
ABSTRACT
This study examined the effects of over-expression of leucine-rich repeats and immunoglobulin-like domains 3 (LRIG3) on the cell cycle and survival of human glioma cell line U87 and U251 and explored the possible mechanisms. The LRIG3 gene was transduced into U87 and U251 cells respectively by using lentivirus and the transduced cells were selected by puromycin. The changes in LRIG3 mRNA and protein levels were measured by RT-PCR and Western blotting. The apoptosis rate was detected by Annexin V-FITC/PI double labeling and the cell cycle was flow cytometrically analyzed. Compared with control cells, LRIG3 mRNA expression in U251 and U87 cells transduced with pLVX-DsRed-LRIG3-Monomer-N1 were increased by 77.6% and 129.7%, and LRIG3 protein expression was raised by 141.3% and 322.7%, respectively. Cell cycle analysis showed that LRIG3 over-expression increased the percentage of cells at G(0)/G(1) phase (P<0.01). Over-expressed LRIG3 could significantly promote the apoptosis of U87 and U251 cells (P<0.05). These findings suggest that the over-expression of LRIG3 could arrest the cell cycle in G(0)/G(1) phase, and promote apoptosis of U87 and U251 cells.
ABSTRACT
The Leucine-rich repeats and immunoglobulin-like domains-2 (LRIG2) gene expression in pituitary adenoma and its correlation with tumor invasiveness were studied. The expression of LRIG2 mRNA and protein in human pituitary adenoma obtained surgically was detected by RT-PCR (39 cases) and immunohistochemical staining (30 cases). It was found that LRIG2 was mostly localized at the nucleus of the pituitary adenoma cells. Its expression was significantly higher in the invasive cases than in the non-invasive cases. LRIG2 protein was positive in 14 cases out of 21 cases of invasive adenoma, but only 2 cases were positive in 9 cases of non-invasive adenoma. The positive expression rate of LRIG2 mRNA was 91.3% in invasive cases (total 23 cases) and 62.5% in non-invasive cases (total 16 cases), respectively. LRIG2 gene is overexpressed in invasive pituitary adenoma. It may play an important role in pituitary adenoma invasiveness and further studies are necessary to elucidate the mechanism under this phenomenon.
ABSTRACT
Three human leucine-rich repeats and immunoglobulin-like domains (LRIG) genes and proteins, named LRIG1-3, has been previously characterized and it was proposed that they may act as suppressors of tumor growth. The LRIG1 protein can inhibit the growth of tumors of glial cells and the down-regulation of the LRIG1 gene may be involved in the development and progression of the tumor. Real-time reverse transcription-polymerase chain reaction (RT-PCR) is a recently developed technique for quantitative assessment of specific RNA levels. In the current study, it was demonstrated that LRIG1-3 and EGFR mRNA was detected in human pituitary adenoma cell lines and a normal pituitary sample, with differences in the expression levels. Compared to the normal pituitary samples, the expression of LRIG1-3 in HP75 cell line was lower, but the expression of EGFR in HP75 cell line was higher. The results are consistent with LRIG1-3 being tumour suppressor genes, and LRIG genes decreasing the expression of EGFR. The ratio of EGFR/LRIG1 was increased at least 13-fold in HP75 cells compared with the normal pituitary cells, which was also the case for the ratio of EGFR/LRIG2 (14-fold increase in HP75) and EGFR/LRIG3 (11-fold increase in HP75). Further studies were needed to elucidate the explicit role of LRIG genes as negative regulators of oncogenesis in human pituitary adenoma.
ABSTRACT
Three human leucine-rich repeats and immunoglobulin-like domains (LRIG) genes and proteins, named LRIG1-3, has been previously characterized and it was proposed that they may act as suppressors of tumor growth. The LRIG1 protein can inhibit the growth of tumors of glial cells and the down-regulation of the LRIG1 gene may be involved in the development and progression of the tumor. Real-time reverse transcription-polymerase chain reaction (RT-PCR) is a recently developed technique for quantitative assessment of specific RNA levels. In the current study, it was demonstrated that LRIG1-3 and EGFR mRNA was detected in human pituitary adenoma cell lines and a normal pituitary sample, with differences in the expression levels. Compared to the normal pituitary samples, the expression of LRIG1-3 in HP75 cell line was lower, but the expression of EGFR in HP75 cell line was higher. The results are consistent with LRIG1-3 being tumour suppressor genes, and LRIG genes decreasing the expression of EGFR. The ratio of EGFR/LRIG1 was increased at least 13-fold in HP75 cells compared with the normal pituitary cells, which was also the case for the ratio of EGFR/LRIG2 (14-fold increase in HP75) and EGFR/LRIG3 (11-fold increase in HP75). Further studies were needed to elucidate the explicit role of LRIG genes as negative regulators of oncogenesis in human pituitary adenoma.
ABSTRACT
The effects of epidermal growth factor (EGF) on proliferation of G15 glioma cells and the possible mechanisms were investigated. GFAP and EGFR expression was detected by immunohistochemical method. After the cells were treated with EGF at different concentrations, cell count method was used to determine the proliferation of glioma cells, cell cycle and apoptosis were analyzed by flow cytometry (FCM), and laser scan confocal microscope (LSCM) was used to measure the cytoplasmic free calcium. The results showed that GFAP was diffusedly expressed in GL15 cells and EGFR was over-expressed. EGF at doses of < or =1 ng/mL could significantly stimulate cell proliferation, cells in phase G0/G1 decreased, and those in phase S increased. EGF at doses of 10 and 100 ng/ml could inhibit the cell proliferation significantly, and the apoptosis ratio in high dose of EGF group was higher than in control group. EGF could significantly induce a quick rise of intracellular free calcium, but the peak value of intracellular free calcium activated by high dose of EGF was higher than by low dose of EGF. It was suggested that EGF had a dual effect on gliomas: low dose of EGF could stimulate the cell proliferation of gliomas, but high dose of EGF could induce the cell apoptosis and inhibit the proliferation of gliomas, which might be contributed to the difference of intracellular free calcium.
ABSTRACT
The expression of epidermal growth factor receptor (EGFR) and leucine-rich repeats and immunoglobulinqike domain 1 (LRIG-1) in humantrigeminal neurinoma was investigated and their effect on the origination and development of trigeminal neurinoma, and the relationship between them was studied. By using immunohistochemistry with tissue chip, the expression of EGFR and LRIG-1 was detected in 23 cases of trigeminal neurinoma. It was found that in the 23 cases, the expression rate of EGFR was 21.74 %, while that of the LRIG-1 was 78.26 %. There was a negative correlation between them. It wassuggested that LRIG-1 might inhibit the malignant differentiation and proliferation of the trigeminal neurinoma possibly by the negative feedback loop of EGFR.
ABSTRACT
The effects of epidermal growth factor (EGF) on proliferation of G 15 glioma cells and the possible mechanisms were investigated. GFAP and EGFR expression was detected by immunohistochemical method. After the cells were treated with EGF at different concentrations, cell count method was used to determine the proliferation of glioma cells, cell cycle and apoptosis were analyzed by flow cytometry (FCM), and laser scan confocal microscope (LSCM) was used to measure the cytoplasmic free calcium. The results showed that GFAP was diffusedly expressed in GL15 cells and EGFR was over-expressed. EGF at doses of ≤ 1 ng/mL could significantly stimulate cell proliferation, cells in phase G0/G1 decreased, and those in phase S increased. EGF at doses of 10 and 100ng/ml could inhibit the cell proliferation significantly, and the apoptosis ratio in high dose of EGF group was higher than in control group. EGF could significantly induce a quick rise of intracellular free calcium, but the peak value of intracellular free calcium activated by high dose of EGF was higher than by low dose of EGF. It was suggested that EGF had a dual effect on gliomas: low dose of EGF could stimulate the cell proliferation of gliomas, but high dose of EGF could induce the cell apoptosis and inhibit the proliferation of gliomas, which might be contributed to the difference of intracellular free calcium.
ABSTRACT
From May, 2000 to June, 2001, 27 patients with Parkinson disease (PD), including 10 cases of rigidity, 13 cases of tremor, 4 cases of rigidity and tremor, were treated by microelectrode-guided technique. Among them, phlebotomy was carried out in 17 cases and thalamotomy in 10 cases. All the targets of lesion were anatomically located by using MR and neurophysiological signals on microelectrode. Our results showed that the efficiency of microelectrode-guided technique for treatment of PD was 98%. The postoperative unified parkinson disease rating scale were 12.3 +/- 9.1 and 13.2 +/- 8.9 respectively, which significantly improved as compared with those before operation. It was concluded that by recognizing special electrical signals in neurons microelectrode-guided neuropsychological techniques can locate target at cellular level, which overcomes the individual difference in anatomy and function, and allow more accuracy, safety and efficiency of operation. This is especially true of PD patients who fail to respond to medical treatment.
Subject(s)
Adult , Female , Humans , Male , Middle Aged , Magnetic Resonance Imaging , Microelectrodes , Parkinson Disease , General Surgery , Stereotaxic Techniques , Thalamus , General SurgeryABSTRACT
From May, 2000 to June, 2001, 27 patients with Parkinson disease (PD), including 10 cases of rigidity, 13 cases of tremor, 4 cases of rigidity and tremor, were treated by microelectrode-guided technique. Among them, phlebotomy was carried out in 17 cases and thalamotomy in 10 cases. All the targets of lesion were anatomically located by using MR and neurophysiological signals on microelectrode. Our results showed that the efficiency of microelectrode-guided technique for treatment of PD was 98%. The postoperative unified parkinson disease rating scale were 12.3 +/- 9.1 and 13.2 +/- 8.9 respectively, which significantly improved as compared with those before operation. It was concluded that by recognizing special electrical signals in neurons microelectrode-guided neuropsychological techniques can locate target at cellular level, which overcomes the individual difference in anatomy and function, and allow more accuracy, safety and efficiency of operation. This is especially true of PD patients who fail to respond to medical treatment.