To study the expression of tankyrase (a positive regulator of telomerase activity) in malignant hematopoietic cells and its relation with telomerase activity, the method of realtime quantitative PCR with fluorescence probe hybridization were used to measure expression of tankyrase and hTERT in myeloid leukemia cell lines K562, HL-60, U937, NB4, THP-1, HEL, Dami and T lymphocytic leukemia cell lines 6T-CEM, Jurkat and B-cell lymphoma cell line Raji. CD3(+), CD19(+) and CD33(+) cells separated from normal human mobilized peripheral blood by immunomagnetic bead system and 10 mononuclear cell samples separated from bone marrow of normal individuals were served as normal controls. The results indicated that the expression of tankyrase in malignant hematopoietic cell lines was significantly higher than that in normal controls (U = 19, P < 0.01). Its expression in myeloid leukemia cell lines is higher than in normal CD33(+) cells, the expression in T lymphocytic leukemia and B-cell lymphoma cell lines is higher than in CD3(+) and CD19(+) cells respectively. Its expression in myeloid malignant hematopoietic cell lines is significantly lower than in lymphocytic ones (0.0032 +/- 0.0010 vs. 0.012 +/- 0.0016, F = 23, P < 0.01). The expression of tankyrase correlated positively with hTERT (Spearman correlation coefficient is 0.395, P < 0.05). It is concluded that tankyrase is overexpressed in malignant hematopoietic cell lines, that may be one of the causes of high-produced telomerase activity in malignant hematopoietic diseases.
DNA-Binding Proteins ; HL-60 Cells ; Humans ; K562 Cells ; Leukemia ; enzymology ; Polymerase Chain Reaction ; Tankyrases ; genetics ; Telomerase ; genetics ; U937 Cells

OBJECTIVETo investigate the inhibition of telomerase activity and cellular proliferation in tongue cancer TCCA-8113 cell lines by antisense human tankyrase-1 RNA treatment, and explore the possibility of the tankyrase-1 as a target of gene therapy for tongue cancer.

METHODSThe replication deficient retrovirus expressing tankyrase-1 antisense RNA was constructed to infect the TCCA-8113 cells. Tankyrase-1 expression was examined by RT-PCR. Telomerase activity was assayed by telomerase repeat amplification protocol (TRAP). Cell proliferation was investigated by cellular growth curve. Cellular apoptosis was detected by flow cytometry method and invert microscope.

RESULTSTankyrase-1 expression and telomerase activity of tongue cancer TCCA-8113 cells were significantly inhibited. There was G(1)-S phase arrest when TCCA-8113 cells were treated with antisense tankyrase-1 transduction. Cellular proliferation was arrested, and cellular apoptosis occurred after antisense tankyrase transduction.

CONCLUSIONSThe transduction of antisense tankyrase-1 by retroviral vector can significantly inhibit the tankyrase-1 expression and telomerase activity of tongue cancer TCCA-8113 cell lines, and arrest the cellular proliferation and promote cellular apoptosis. The tankyrase may be a potential target of gene therapy for tongue cancer.

Apoptosis ; Cell Line, Tumor ; Cell Proliferation ; Genetic Therapy ; Genetic Vectors ; genetics ; Humans ; RNA, Antisense ; genetics ; Retroviridae ; genetics ; Tankyrases ; genetics ; Telomerase ; metabolism ; Tongue Neoplasms ; genetics ; metabolism ; pathology ; therapy ; Transfection

Apoptosis ; physiology ; Cell Cycle ; physiology ; Humans ; Neoplasms ; etiology ; metabolism ; Tankyrases ; genetics ; physiology ; Telomerase ; metabolism ; physiology ; Telomere ; genetics ; metabolism ; Telomere-Binding Proteins ; genetics ; physiology ; Telomeric Repeat Binding Protein 1 ; genetics ; physiology ; Telomeric Repeat Binding Protein 2 ; genetics ; physiology

BACKGROUNDChemotherapy is the most frequently adopted adjuvant therapy of pancreatic ductal adenocarcinoma (PDAC), but the development of drug resistance reduces its effectiveness. Clarification of the mechanism of multidrug resistance (MDR) development in PDAC is needed to improve the therapeutic effect of chemotherapy. This study was aimed to investigate the molecular mechanism of MDR of PDAC and to identify genes associated with MDR development.

METHODSThe gene expression profiles of cell line SW1990 and three drug-selected pancreatic chemoresistant sub-lines, SW1990/5-Fu, SW1990/ADM and SW1990/GEM, were obtained using an oligonucleotide microarray (Affymetrix HG U133 2.0 plus) that contained approximately 38,000 human genes. The microarray results were validated by real-time quantitative polymerase chain reaction and Western blot analysis.

RESULTSThere were 165 genes and expressed sequence tags, some of which have never been linked to drug resistance, that were up- or down-regulated at least 2-fold in all resistant sub-lines when compared with SW1990. According to Gene Ontology annotation, differentially expressed genes related to MDR in pancreatic cancer belong to many functional families and with diverse biological processes. Genes related to antioxidant activity, apoptosis, the cell cycle, signal transduction and intracellular adhesion may undergo epigenetic changes preceding MDR development. A hierarchical clustering was conducted and several interesting clusters were discovered that may be primarily related to cell cycle and developmental regulation. A prediction rule was built from the expression profiles of 117 genes after support vector machine (SVM) analysis, and the prediction result was examined by cytotoxic testing. As a result, a differential gene expression pattern was constructed in multidrug resistant pancreatic cancer cells.

CONCLUSIONSThe findings of this study prove that construction of a chemoresistance prediction rule, based on gene expression patterns, is practical. These data provide new insights into the molecular mechanism of pancreatic cancer MDR development and may be useful for the detection and treatment of MDR in pancreatic cancer patients.

Cell Cycle Proteins ; genetics ; Cell Line, Tumor ; Computational Biology ; Drug Resistance, Multiple ; Drug Resistance, Neoplasm ; Gene Expression Profiling ; Glutathione Peroxidase ; genetics ; Glutathione Transferase ; genetics ; Humans ; Microtubule-Associated Proteins ; genetics ; Oligonucleotide Array Sequence Analysis ; methods ; Pancreatic Neoplasms ; drug therapy ; genetics ; Tankyrases ; genetics