Pten gene is the first antioncogene with dual phosphatase activity discovered so far, pten gene regulates the cell cycle progress, apoptosis, metastasis and invasion of the tumor cells through negatively regulating the multiple signaling transduction pathways. Multiple myeloma (MM) is a malignant tumor occurring in terminal stage of B cell differentiation. The genetic changes are considered as the important factors in MM pathogenesis, among which the deletion of antioncogene is a critical genetic change. However, little is known about the genetic change of pten in MM. This review summarizes the research advance on pten in MM including structure of pten, mechanism of pten effect and correlation of pten with MM in order to provide some references for the investigating new gene target to treat the MM.
Humans ; Multiple Myeloma ; metabolism ; therapy ; PTEN Phosphohydrolase ; genetics ; metabolism ; Signal Transduction

OBJECTIVETo explore PTEN gene expression and its clinical significance in acute leukemia.

METHODSThe expression levels of PTEN mRNA in 5 leukemia cell lines, 87 patients with acute leukemias (AL), including 59 acute myeloid leukemia (AML), 26 acute lymphoblastic leukemia (ALL), and 2 acute hybrid leukemia, 21 AL in complete remission (AL-CR), 31 chronic myelogenous leukemia (CML) and 14 normal controls were assayed by RT-PCR.

RESULTSPTEN mRNA was detected in K562 cell line, but not in Kasumi-1, HL-60, U937, Nalm-6 cell lines. The expression ratio of PTEN mRNA between CML (61.29%) and normal control (78.57%) had no statistical difference (P > 0.05). The expression ratios of PTEN mRNA in AL (18.39%) and AL-CR (42.86%) were significantly lower than that in normal control (P < 0.01 and P < 0.05, respectively), AL also has a lower expression ratio than that of AL-CR (P < 0.05). The decreased level of PTEN mRNA had a positive correlation with poor-prognostic factors (high white blood cell count of > or = 20 x 10(9)/L and chromosome abnormality).

CONCLUSIONThere is down-regulated expression of PTEN gene in AL. PTEN gene may play a role in leukemogenesis.

Cell Line, Tumor ; Humans ; Leukemia ; genetics ; metabolism ; PTEN Phosphohydrolase ; genetics ; metabolism ; RNA, Messenger ; genetics ; Reverse Transcriptase Polymerase Chain Reaction

Bone Marrow Cells ; metabolism ; DNA-Activated Protein Kinase ; genetics ; metabolism ; Humans ; Leukemia ; genetics ; Nuclear Proteins ; genetics ; metabolism ; PTEN Phosphohydrolase ; genetics ; metabolism ; RNA, Messenger ; Telomerase ; genetics ; metabolism

OBJECTIVETo investigate the effect of knocking-down microRNA-221 (miR-221) expression on the radiosensitivity of human colorectal carcinoma cells.

METHODSHuman colorectal carcinoma-derived cell line Caco2 was transfected with miR-221 antisense oligonucleotides (anti-miR-221) via Lipofectamine 2000. Real-time quantitative PCR was performed to detect the expression of miR-221 and PTEN mRNA in Caco2 cells. The changes in the protein expression of PTEN in the transfected cells were detected by Western blotting. The cell death after transfection and irradiation was detected by flow cytometry.

RESULTSTransfection with anti-miR-221 caused a significant reduction in miR-221 expression (P<0.05) and up-regulated PTEN protein expression (P<0.05) in Caco2 cells. The percentage of cell death was significantly increased in anti-miR-221 group and anti-miR-221 with irradiation group (P<0.01). Anti-miR-221 significantly enhanced the radiosensitivity of Caco2 cells, which was partially reversed by PTEN-siRNA.

CONCLUSIONAnti-miR-221 can enhance the radiosensitivity of colorectal carcinoma cells by up-regulating the expression of PTEN.

Caco-2 Cells ; radiation effects ; Colorectal Neoplasms ; genetics ; metabolism ; Humans ; MicroRNAs ; genetics ; metabolism ; PTEN Phosphohydrolase ; metabolism ; RNA, Messenger ; genetics ; Radiation Tolerance ; Transfection ; Up-Regulation

Objective: To investigate the effect of adenovirus-mediated shRNA down-regulating phosphatase and tensin homolog deleted on chromosome 10 (PTEN) expression on vinculin, filamin A, and cortactin in activated hepatic stellate cells (HSCs). Methods: Activated rats hepatic stellate cell line (HSC-T6) was cultured in vitro. Recombinant adenovirus Ad-shRNA/PTEN carrying PTEN targeted RNA interference sequence [short hairpin RNA (shRNA)] and empty control virus Ad-GFP were transfected into HSCs. The PTEN mRNA and protein expression of HSCs in each group were detected by real-time fluorescence quantitative PCR and Western blot. The expressional change of vinculin, filamin A and cortactin in HSCs of each group were detected by confocal laser scanning immunofluorescence microscope. Image-pro plus 6.0 software was used for image analysis and processing. The integrated optical density (IOD) of the fluorescence protein expression was measured. The experiment was divided into three groups: control group (DMEM instead of adenovirus solution in the adenovirus transfection step), Ad-GFP group (transfected with empty virus Ad-GFP only expressing green fluorescent protein), and Ad-shRNA/PTEN group (recombinant adenovirus Ad-shRNA/PTEN carrying shRNA targeting PTEN and expressing green fluorescent protein). One-way analysis of variance was used for comparison of mean value among the three groups, and LSD-test was used for comparison between the groups. Results: shRNA targeted PTEN was successfully transfected and the expression of PTEN mRNA and protein in HSC (P < 0.05) was significantly down-regulated. HSCs vinculin was mainly expressed in the cytoplasm. HSCs vinculin fluorescence IOD in the Ad-shRNA/PTEN group (19 758.83 ± 1 520.60) was higher than control (7 737.16 ± 279.93) and Ad-GFP group (7 725.50 ± 373.03) (P < 0.05), but there was no statistically significant difference between control group and Ad-GFP group (P > 0.05). There was no statistically significant difference in the fluorescence IOD of Filamin A among the three groups (P > 0.05), but the subcellular distribution of Filamin A among the three groups were changed. Filamin A in the Ad-shrNA /PTEN HSC group was mainly distributed in the cytoplasm. Filamin A HSC was mainly located in the nucleus.The filamin A HSC in the control group and Ad-GFP group was mainly located in the nucleus. The nucleocytoplasmic ratio of Filamin A in the AD-shrNA /PTEN group (0.60 ± 0.15) was significantly lower than control group (1.20 ± 0.15) and Ad-GFP group (1.08 ± 0.23), P < 0.05. but there was no statistically significant difference in filamin A nucleocytoplasmic ratio of HSC between the control group and the Ad-GFP group (P > 0.05). Cortactin HSCs in the three groups was mainly distributed in the cytoplasm. The cortactin fluorescence IOD of HSCs in the Ad-shRNA/PTEN group was significantly higher than control group (22 959.94 ± 1 710.42) and the Ad-GFP group (22 547.11 ± 1 588.72 ) (P < 0.05), while there was no statistically significant difference in the IOD of cortactin fluorescence in HSCs between the control group and the Ad-GFP group (P > 0.05). Conclusion: The down-regulation of PTEN expression raises the expression of microfilament-binding protein vinculin and cortactin, and changes the subcellular distribution of another microfilament binding protein filamin A, that is, translocation from nucleus to the cytoplasm in activated HSC in vitro.
Adenoviridae/metabolism* ; Animals ; Carrier Proteins ; Cell Proliferation ; Cortactin ; Filamins/genetics* ; Hepatic Stellate Cells/metabolism* ; PTEN Phosphohydrolase/metabolism* ; RNA, Small Interfering/genetics* ; Rats ; Vinculin/genetics*

OBJECTIVETo investigate the expressions of phosphorylated Smad2 (P-Smad2) and phosphatase and tensin homolog deleted on chromosome ten (PTEN) in hepatocellular carcinoma (HCC) tissues.

METHODSThe expressions of P-Smad2 and PTEN were detected using Envision immunohistochemical technique in 31 cases of HCC tissues, 25 cases of HCC adjacent liver tissues and 13 cases of non-hepatocellular carcinoma tissues.

RESULTSThe positive expression and staining intensity of PTEN in the cytoplasm of HCC cells (64.5%, 4.19+/-3.31) was significantly lower than those of the cells of the cancer adjacent tissues and non-cancerous tissues (96.0%, 7.88+/-0.93; 100%, 7.77+/-0.93). The staining intensity of PTEN in the cytoplasm of Edmondson pathologic grade III HCC cells was lower than those of the Edmondson grade I. The expression of PTEN was negatively correlated with intrahepatic vascular cancer thrombi (r=-0.43) and the expression of PTEN in the nuclei or cytoplasm of liver cells was negatively correlated with the liver disease progressions (r=-0.34). The positive rate and expression intensity of phosphorylated Smad2 in nuclei of HCC cells were the same as those in cancer adjacent and non-tumor liver tissues. The expression was mostly in the nucleus and cytoplasm of Edmondson grade I HCC cells, cancer adjacent liver tissue cells and non-tumor liver tissues, but its expression was only in the nuclei of Edmondson grade II and III HCC cells. The phosphorylated Smad2 expression appeared in the nuclei and in the cytoplasm of liver cells and it was positively correlated with the severity of the tumor pathology (r=0.22). Spearman correlation analysis revealed a significant inverse correlation between PTEN and phosphorylated Smad2 in HCC tissues (r=-0.73).

CONCLUSIONSThe aberrant expressions of PTEN and phosphorylated Smad2 and their interaction may play an important role in the pathogenesis of hepatocellular carcinoma.

Adult ; Aged ; Carcinoma, Hepatocellular ; genetics ; metabolism ; pathology ; Female ; Humans ; Liver Neoplasms ; genetics ; metabolism ; pathology ; Male ; Middle Aged ; Neoplasm Staging ; Oxidative Phosphorylation ; PTEN Phosphohydrolase ; metabolism ; Smad2 Protein ; metabolism

OBJECTIVETo construct the recombinant adenovirus expression vector of a short hairpin RNA (shRNA) targeting phosphatase and tensin homolog deleted on chromosome ten (PTEN) gene for gene therapy of ischemic cerebral injury.

METHODSThe U6 expression promoter and shRNA of pGenesil-1-shRNA, which was constructed and identified in our previous experiment, were subcloned to pAdTrack shuttle plasmid. The product pAdTrack-U6-shRNA was linearized by PmeI for homologous recombination with pAdEasy-1 in pAdEasy-1 competence bacteria. The positive clone was identified by enzyme digestion, PCR analysis and DNA sequence analysis. After linearization by PacI, the recombinant adenovirus DNA shuttle plasmid pAdEasy-U6-shRNA was transfected into 293 cells for packaging and amplification of Ad-U6-shRNA, which was further identified by PCR analysis and DNA sequence analysis. Western blotting was used to detect the expression of PTEN protein in the hippocampal neurons infected with the adenovirus.

RESULTSThe pAdTrack-U6-shRNA and pAd-U6-shRNA plasmids had been successfully constructed as verified by PCR analysis, enzyme digestion and DNA sequence analysis. PCR analysis and DNA sequence analysis confirmed successful packaging of the recombinant adenovirus Ad-U6-shRNA in 293 cells. PTEN protein expression decreased significantly in the hippocampal neurons after infection by the recombinant virus.

CONCLUSIONWe have successfully constructed the recombinant adenovirus Ad-U6-shRNA targeting PTEN gene, which provides a basis for investigating the role of PTEN in neuroprotection after cerebral ischemic injury using RNA interference.

Adenoviridae ; genetics ; metabolism ; Genetic Vectors ; genetics ; Humans ; PTEN Phosphohydrolase ; biosynthesis ; genetics ; RNA Interference ; RNA, Small Interfering ; genetics ; Recombinant Proteins ; biosynthesis ; genetics ; Sequence Analysis, DNA

OBJECTIVETo investigate the effects of exogenous wild PTEN gene stably transfection on growth of breast cancer cells in vitro.

METHODSAt first, a recombinant eukaryotic expression plasmid pcDNA3.1-PTEN was constructed. Human breast cancer cell line MDA468 was transfected with pcDNA3.1-PTEN or mock transfected plasmid pcDNA3.1(-) with lipofectamine. RT-PCR, immunohistochemical staining and Western blot were used to determine target gene expression. Cell viability was tested by MTT assay. Apoptosis was determined by flow cytometry with a double-staining method using FITC-conjugated annexin V and PI.

RESULTSThe PTEN stably transfected cells demonstrated the integration of the exogenous target gene and corresponding mRNA and protein over-expression. There was a significant decline in cell viability of pcDNA3.1-PTEN transfected MDA468 cells in comparison with the mock-transfected ones (P < 0.01). The PTEN-trasfected MDA468 cells also showed an increase in the rate of apoptosis, compared with parental and mock-trasfected cells (P < 0.001).

CONCLUSIONStable expression of exogenous PTEN can suppress the malignant phenotypes of the human breast cancer cell line MDA468.

Breast Neoplasms ; metabolism ; pathology ; Cell Line, Tumor ; Eukaryotic Cells ; metabolism ; Humans ; PTEN Phosphohydrolase ; biosynthesis ; genetics ; Phenotype ; Plasmids ; genetics ; Recombinant Proteins ; biosynthesis ; genetics ; Transfection

Polyethylenimine (PEI) is one of the most characterized non-viral vectors. It can condense DNA in a good manner and achieve high transfection efficiency. Minicircle DNA (mc-DNA) is a novel kind of supercoiled DNA which is devoid of bacterial backbone. mc-DNA is superior to conventional DNA for its higher transfection efficiency and longer time-span. In this study, we combined PEI and mc-DNA in gene delivery system. We investigated the physicochemical and biochemical effects of this non-viral system and further explore its potential in tumor gene therapy. mc-DNA was obtained by recombination of parental plasmid in the presence of L-arabinose, and complexed with PEI. The results of transmission electron microscopy and scanning electron microscopy showed that the particles were spherical and homogeneous. Through gel retardation assay and MTT assay, we found that there were no obvious differences in binding capability of PEI to mc-DNA and plasmid DNA, as well as in cytotoxicity. The results of dynamic light scattering showed that the size of PEI/mc-DNA was about 68 nm, a slight larger than that of PEI/plasmid DNA. Furthermore, the tumor cells transfected with mc-GFP showed higher GFP expression level than that of conventional plasmid. The same results were achieved in the cells treated with tumor-suppressor gene pten, assayed by RT-PCR and Western blot. It indicates that the system of PEI/minicircle DNA is promising in gene transfer.
DNA, Circular ; genetics ; Gene Transfer Techniques ; Genetic Vectors ; genetics ; Green Fluorescent Proteins ; genetics ; Nanoparticles ; chemistry ; PTEN Phosphohydrolase ; genetics ; Polyethyleneimine ; metabolism ; Transfection

The study was aimed to explore the correlation of expression of pten mRNA and PTEN protein with AKT phosphorylation levels in various types of leukemia and to elucidate its role in the pathogenesis of leukemia so as to provide some evidence for using PI3K/AKT pathway inhibitors in future. 128 de novo leukemia patients were enrolled in this study, including 61 AML cases, 27 ALL cases, 24 CML cases, and 16 CLL cases. 21 volunteers were selected as normal control. The RT-PCR and Western blot were used to assay the expressions of pten mRNA, PTEN protein, and P-AKT protein in Jurkat cells, bone marrow mononuclear cells of patients respectively. The results showed that the expressions of pten mRNA and PTEN protein in Jurkat cells were lower than that in normal control group; the expression of pten mRNA in AML group was lower than that in normal control group, but the difference was not significant (p=0.274); the expressions of pten mRNA in ALL, CML, CLL each group were lower than that in normal control group, and the difference was significant (p<0.05). Compared with normal control group, the expression of PTEN protein was lower and the expression of P-AKT protein was higher in AML, ALL, CML, CLL each group, the difference were significant (p<0.05). It is concluded that the a lower expression of PTEN protein and higher expression of P-AKT protein may play an important role on leukemia pathogenesis, and inactivation of PTEN protein mainly occurs in the level of protein translation.
Bone Marrow Cells ; metabolism ; Case-Control Studies ; Humans ; Jurkat Cells ; Leukemia ; metabolism ; pathology ; PTEN Phosphohydrolase ; metabolism ; Phosphorylation ; Proto-Oncogene Proteins c-akt ; metabolism ; RNA, Messenger ; genetics