OBJECTIVESTo obtain prokaryotic expressed IA-2 recombinant protein and to identify its immunological activity.

METHODSThe complimentary DNA (cDNA) coding for the intracytoplasmic part of IA-2 (IA-2ic) was amplified from human fetal brain RNA, and was subcloned into the PinPoint Xa-1 T vector to construct recombinant expression plasmid, and was then expressed in E. coli JM109 cells as a fusion protein with a biotinylated peptide sequence at the aminoterminus. The biotinylated fusion protein was then purified by affinity chromatography and was subsequently dialyzed. Finally, its immunogenicity was evaluated by enzyme linked immunosorbent assay (ELISA).

RESULTSThe purified IA-2ic fusion protein resolved on sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) as a single Coomassie brilliant blue stained band with a molecular weight of 59 kDa and its immunogenicity was confirmed by ELISA.

CONCLUSIONSE. coli expressed IA-2ic fusion protein has immunological activity. It can be used for detection of IA-2 autoantibodies (IA-2A) and for further studies on type 1 diabetes in future.

Animals ; Autoantigens ; biosynthesis ; DNA, Complementary ; analysis ; Diabetes Mellitus, Type 1 ; immunology ; Escherichia coli ; genetics ; Humans ; Membrane Proteins ; biosynthesis ; genetics ; isolation & purification ; Plasmids ; Protein Tyrosine Phosphatase, Non-Receptor Type 1 ; Protein Tyrosine Phosphatases ; biosynthesis ; genetics ; isolation & purification ; Rabbits ; Receptor-Like Protein Tyrosine Phosphatases, Class 8 ; Recombinant Fusion Proteins ; biosynthesis ; immunology ; isolation & purification

OBJECTIVETo construct a retrovirus-mediated expression system carrying human SHP-1 gene to transfer SHP-1 gene in human breast cancer MDA-MB-231 cells.

METHODSThe full-length SHP-1 gene fragment was amplified by RT-PCR from the total RNA extracted from human breast cancer cell line MCF-7 over-expressing SHP-1 protein. The gene fragment was inserted into the vector pLNCX2 to construct the recombinant retroviral plasmid, which was transfected into the packaging cell PT67 via Lipofectamine2000. A cell line stably producing the virus was selected with G418. MDA-MB-231 cells was infected with the virus, and the expression of SHP-1 gene in the positive cell clone was detected with Western blotting.

RESULTSA 1.8 kb cDNA fragment of SHP-1 gene was obtained from MCF-7 cells and successfully inserted into the pLNCX2. A stable cell clone PT67/SHP-1 and virus supernatant were obtained. Expression of SHP-1 protein was detected in the cells infected with the virus.

CONCLUSIONThe recombinant retroviral vector carrying SHP-1 gene has been successfully constructed and MDA- MB-231/SHP-1 cell line expressing SHP-1 has been obtained to allow further functional study of SHP-1 in breast cancer.

Breast Neoplasms ; genetics ; metabolism ; pathology ; Cell Line, Tumor ; Cloning, Molecular ; Genetic Vectors ; genetics ; Humans ; Protein Tyrosine Phosphatase, Non-Receptor Type 6 ; biosynthesis ; genetics ; Recombinant Proteins ; biosynthesis ; genetics ; Retroviridae ; genetics ; metabolism ; Reverse Transcriptase Polymerase Chain Reaction ; Transfection

OBJECTIVETo investigate the role of mitogen activated protein kinase phosphatase-1 (MKP-1) in mediating acquired multidrug resistance in pancreatic adenocarcinoma cell line SW1990/Fu.

METHODSTo detect MKP-1 mRNA expression, Northern blot analysis was carried out in well established drug resistant pancreatic adenocarcinoma cell line SW1990/Fu, SW1990 and MiaPaCa-2 cell lines. To further elucidate the exact role of MKP-1, Western blot hybridization was performed in these three cell lines.

RESULTSNorthern blot analysis of total RNA isolated from SW1990/Fu, SW1990 and MiaPaCa-2 cell lines revealed the presence of the 2400 bp MKP-1 transcript 7 at relatively high levels in pancreatic cancer cell lines SW1990 and MiaPaCa-2. In the SW1990/Fu, the MKP-1 transcript was detectable at very low level. Densitometric analysis with normalization to 7S indicated that MKP-1 mRNA expression level was significantly decreased in SW1990/Fu in comparison with the parental and MiaPaCa-2 cell lines. MKP-1 protein expression level in SW1990/Fu detected by Western blot was coincident with mRNA level.

CONCLUSIONSMKP-1 may be involved in acquired multidrug resistance in pancreatic adenocarcinoma, and we could hypothesized that alterations of intra-cellular transduction signal system acts as an important role in multidrug resistance of tumor cells.

Adenocarcinoma ; drug therapy ; enzymology ; pathology ; Blotting, Northern ; Blotting, Western ; Cell Cycle Proteins ; biosynthesis ; genetics ; physiology ; Cell Line, Tumor ; Down-Regulation ; Drug Resistance, Multiple ; Drug Resistance, Neoplasm ; Dual Specificity Phosphatase 1 ; Humans ; Immediate-Early Proteins ; biosynthesis ; genetics ; physiology ; Pancreatic Neoplasms ; drug therapy ; enzymology ; pathology ; Phosphoprotein Phosphatases ; biosynthesis ; genetics ; physiology ; Protein Phosphatase 1 ; Protein Tyrosine Phosphatases ; biosynthesis ; genetics ; physiology ; RNA, Messenger ; genetics

Gene Expression Profiling ; Humans ; Killer Cells, Natural ; pathology ; Lymphoma, T-Cell ; genetics ; metabolism ; pathology ; Nose Neoplasms ; genetics ; metabolism ; pathology ; Oligonucleotide Array Sequence Analysis ; Protein Tyrosine Phosphatase, Non-Receptor Type 6 ; biosynthesis ; genetics ; RNA, Messenger ; biosynthesis ; genetics

The amino acid sequence (1-301aa) coding the human PTP1B catalytic domain (PTP1Bc) was obtained from the GenBank. The PTP1Bc gene was constructed by overlapping PCR, then was inserted into vector pET-22b(+) and expressed efficiently in E. coli BL21(DE3) under optimum condition after IPTG induction. The proteins were expressed mainly as inclusion bodies with the yield of more than 30% of total bacterial proteins. The expressed products were purified through Ni(2+)-affinity chromatographic column. After purification, the purity of the proteins was more than 95%. Western blotting analysis suggested that the purified proteins could specially combine with anti-PTP1B antibody. Enzyme activity assay showed that the protein has phosphatase activities.
Catalysis ; Escherichia coli ; genetics ; metabolism ; Genetic Vectors ; genetics ; Humans ; Inclusion Bodies ; metabolism ; Polymerase Chain Reaction ; methods ; Protein Tyrosine Phosphatase, Non-Receptor Type 1 ; biosynthesis ; genetics ; Recombinant Proteins ; biosynthesis ; genetics ; metabolism

Fas transduces apoptotic signals upon cross-linking with the Fas ligand (FasL), which is experimentally replaced by agonistic anti-Fas monoclonal antibodies (mAb). Of eight human malignant hematopoietic cell lines (HL-60, KG-1, THP-1, K562, U937, Jurkat, IM-9, RPMI-8226) examined by flow cytometric analysis, all, except K562, were found to be positive for surface Fas antigen. However, despite surface Fas expression, the agonistic anti-Fas mAb (7C11) induced apoptosis in only three of seven Fas-expressing cell lines (KG-1, Jurkat and IM-9). This Fas-resistance did not correlated with high levels of mRNA either for DcR3, a decoy receptor for FasL, or for FAP-1, a Fas-associated phosphatase that can block the apoptotic function of Fas. Reverse transcriptase-polymerase chain reaction (RT-PCR) analysis did not show consistent differences in the expression of Bcl-2 and Bax between Fas-sensitive and Fas-resistant cell lines examined. These findings indicated that the presence or absence of mRNA expression of DcR3, FAP-1, Bcl-2 and Bax did not always correlate with relative sensitivity to Fas-mediated apoptosis. Treatment of cells with cycloheximide converted the phenotype of resistant cell lines from Fas-resistant to Fas-sensitive, and enhanced the sensitivity of Fas-sensitive cell lines. These results suggest that the Fas-resistance is dependent on the presence of labile proteins that determine resistance to Fas-mediated apoptosis and the apoptotic machinery is already in place in Fas-resistant cell lines.
Antigens, CD95/*metabolism ; Apoptosis/drug effects/*genetics ; Carrier Proteins/biosynthesis/genetics ; Comparative Study ; Cycloheximide/pharmacology ; Gene Expression Regulation, Neoplastic ; Hematologic Neoplasms/*genetics/metabolism ; Human ; Membrane Glycoproteins/*metabolism ; Protein Synthesis Inhibitors/pharmacology ; Protein-Tyrosine-Phosphatase/biosynthesis/genetics ; Proto-Oncogene Proteins/biosynthesis/genetics ; Proto-Oncogene Proteins c-bcl-2/biosynthesis/genetics ; Receptors, Cell Surface/biosynthesis/genetics ; Signal Transduction ; Support, Non-U.S. Gov't ; Tumor Cells, Cultured

The aim of study is to investigate the expression of hematopoietic cell phosphatase (SHP-1) gene and c-kit pro-oncogene in acute leukemia (AL) and its impact on prognosis in AL. Semi-quantity reverse transcriptase-polymerase chain reaction (RT-PCR) was used to detect the expression of SHP-1 mRNA and c-kit mRNA in 60 AL patients and 33 normal controls (NC). The results showed that the positive rates of SHP-1 expression from high to low level were found orderly in complete remission group, newly diagnosed group and relapsed group, there was significance difference between each group and NC group (P < 0.05). The positive rates of c-kit expression were opposite order in each groups as compared with SHP-1. there was also significance difference between each group and NC group (P < 0.05). The positive rate of SHP-1 and c-kit expressions in AML was higher than that in ALL (P < 0.05), there was negative correlation between expressions of SHP-1 and c-kit (r = -0.502, P < 0.05); The difference between the complete remission rate in SHP-1 positive and in SHP-1 negative patients from 30 newly diagnosed AML patients was significant (P < 0.05), the same result was found between c-kit(+) complete remission and c-kit(-) complete remission. It is concluded that SHP-1 gene is a potentially anti-oncogene and inhibits the growing of tumor by negatively modulating c-kit gene. Simultaneous detection of SHP-1 and c-kit gene may act as a factor for predicting prognosis in AL.
Adolescent ; Adult ; Aged ; Female ; Humans ; Leukemia, Myeloid, Acute ; genetics ; metabolism ; Male ; Middle Aged ; Polymerase Chain Reaction ; Precursor Cell Lymphoblastic Leukemia-Lymphoma ; genetics ; metabolism ; Prognosis ; Protein Tyrosine Phosphatase, Non-Receptor Type 6 ; biosynthesis ; genetics ; metabolism ; Proto-Oncogene Proteins c-kit ; biosynthesis ; genetics

OBJECTIVETo explore the transcription regulation of 5-aza-2'-deoxycytidine(5-Aza-CdR) on SHP-1 gene and its effects on Daudi cell line growth.

METHODSMTT method and flow cytometry were used to detect the growth and apoptosis of Daudi cells after treated with different dosage of 5-Aza-CdIR. Bisulfite sequencing PCR ( BSP) , T-A cloning and sequence analysis were evaluated for methylation status. The SHP-I mRNA and protein were determined by reverse transcription polymerase chain reaction (RT-PCR) ,immunohistochemistry.

RESULTS(1)After 7 d treatment with 2. 00 micromol/L of 5-Aza-CdR, all cytosines (C) in Daudi cells genome DNA were converted to thymidine, and SHP-1 mRNA and protein expressed again in the cells while those Cs in CpG dinucleotides in untreated Daudi cells remained Cs; (2)5-Aza-CdR inhibited the cell growth,The effects within certain extent were dose and time dependent:after 72 h treatment with 5-Aza-CdR at 200. 00, 20. 00, 2. 00 and 0. 20 micromol/L, the inhibitive rates were 72. 0% , 65. 1%, 51. 5%, 28.8% ,23.4% respectively; (3) 5-Aza-CdR increased apoptosis rate of tumor cells with a dose and times dependent manner within certain extent, too:at the 1,3,5 d treatment with 5-Aza-CdR 2. 00 micromol/L,the apoptosis rates were 2. 3% ,10. 8 % and 17. 1% ; respectively. (4) 5-Aza-CdR also changed cell cycle of tumor cells: at 24 h treatment with 5-Aza-CdR 2.00 micromol/L,92. 7% tumor cells stopped at S phase and G, phase cells were increased gradually with time.

CONCLUSIONDNA promoter hypermethylation is associated with SHP-1 gene silence in Daudi lymphoma cell line. 5-Aza-CdR could effectively cause demethylation and inhibit the growth of tumor cell by reactivating the gene transcription.

Antimetabolites, Antineoplastic ; pharmacology ; Apoptosis ; Azacitidine ; analogs & derivatives ; pharmacology ; Cell Line, Tumor ; Cell Proliferation ; drug effects ; DNA Methylation ; Dose-Response Relationship, Drug ; Humans ; Lymphoma ; genetics ; pathology ; Protein Tyrosine Phosphatase, Non-Receptor Type 6 ; biosynthesis ; genetics ; RNA, Messenger ; biosynthesis ; Reverse Transcriptase Polymerase Chain Reaction