ABSTRACT
<p><b>OBJECTIVE</b>To investigate the effect of gene Af116609 on gastric cancer multi-drug resistance (MDR) by introducing it into gastric cancer multi-drug resistant (MDR) cell line SGC7901/VCR.</p><p><b>METHODS</b>Gene Af116609 was cloned from SGC7901/VCR by RT-PCR and its differential expression between gastric cancer MDR cells and its parental cells was displayed by Northern blot. The gene was introduced to gastric cancer cells by transfection of recombinant eukaryotic expression vector by electroporation. MTT assay in vitro was applied to investigate its effect on multi-drug resistance phenotype of gastric cancer cells.</p><p><b>RESULTS</b>The full length CDS of gene Af116609, as long as 327 bp, was cloned from gastric cancer MDR cell line SGC7901/VCR and its sequence was coincident with the hypothetical gene Af116609 in GenBank. It was overexpressed in MDR cells than its parental cells at mRNA level. In the MTT assay in vitro, the drug sensitive cells transfected with sense eukaryotic expression vector showed upregulated targeted gene, with increased resistance to vincristine, 5-fliorouracil and arabinoside, and decreased resistance to adriamycin, but no influence on resistance to methotrexate. However, the drug resistant cells transfected with anti-sense eukaryotic expression vector, showed down regulated targeted gene, with less resistance to all the five anticancer drugs to different degrees.</p><p><b>CONCLUSION</b>Gene Af116609 is related to MDR phenotype of gastric cancer cells and may become a candidate molecular target to reverse the MDR of gastric cancer.</p>
Subject(s)
Humans , Antineoplastic Agents, Phytogenic , Pharmacology , Autoantigens , Genetics , Cell Line, Tumor , Drug Resistance, Multiple , Genetics , Drug Resistance, Neoplasm , Genetics , RNA, Small Cytoplasmic , Genetics , Ribonucleoproteins , Genetics , Stomach Neoplasms , Genetics , Pathology , Vascular Endothelial Growth Factor A , Vincristine , PharmacologyABSTRACT
Translocating protein and translocating peptides have therapeutic potential against tumors by exposing the cytotoxic domains of toxic proteins to the cell cytosol. The aim of this study is to investigate the effect of N-terminally fused PE translocating peptides on granzyme B (GrBa) activity. PE II-GrBa fusion protein genes were constructed by replacing N-terminal signal and acidic dipeptide sequence of human granzyme B gene with two truncated translocating sequences of Pseudomonas exotoxin A (PE II aa 280-364/358) by recombinant PCR, and then cloned into pIND inducible expression vector. The resulting pIND-PE II-GrBa expression vectors were co-transfected with assistant plasmid pVgRXR into HeLa cells through lipofectamine, followed by selection on G418 and zeocin. The resistant cells were collected and induced with ponasterone A. Western blot analysis demonstrated that ponasterone A induction caused the expression of PE II-GrBa fusion proteins, and indirect immunofluorescence detected giant sized multinucleated cells, suggesting cytoskeletal and mitotic abnormalities as reported in our previous studies. Western blot, enzymatic activity assay and cell counting analysis indicated that two types of PE II-GrBa fusion proteins were capable of cleaving both endogenous and exogenous substrates of granzyme B, and inhibiting the growth of cells. The PE II (aa 280-358)-GrBa was shown to have higher serine protease activity and stronger growth inhibitory effect. Such inhibition was presumably associated with G2 arrest as determined by cell cycle analysis. These data prove that PE II-GrBa fusion proteins have cell inhibitory effect similar to GrBa, and that the shorter PE-derived peptide exerts less influence on GrBa activity. This study helps to optimize the construction of recombinant protein comprising translocating peptides and cytotoxic molecules for tumor cell killing.
Subject(s)
Humans , ADP Ribose Transferases , Genetics , Pharmacology , Bacterial Toxins , Genetics , Pharmacology , Cell Proliferation , Exotoxins , Genetics , Pharmacology , Granzymes , Genetics , Pharmacology , HeLa Cells , Recombinant Fusion Proteins , Pharmacology , Virulence Factors , Genetics , PharmacologyABSTRACT
To explore the effect of a tyrosine-kinase inhibitor STI571 and P21(WAF) gene clone on the proliferation, cycle, apoptosis of leukemia cell line K562, P21(WAF) gene was obtained by RT-PCR, and its sequence was approved to be correct, then P21-pcDNA3.1 vector was constructed and transfected into K562 cell line. After selected with G418, P21-pcDNA3.1-K562 cell clone that stably expression P21(WAF) was isolated. P21(WAF) protein was identified by Western blot. The survival rate were tested by MTT. Cell cycle and apoptosis were tested by flow cytometry. The results showed that the expression of P21(WAF) protein could be detected by Western blot in P21-pcDNa3.1-K562 cells. A strong inhibition of cell proliferation was observed in P21-pcDNA3.1-K562 cells as compared with that of the control. The cells cycle were arrested in G(0)/G(1) phase. The percentage of apoptosis was declined slightly after P21-pcDNA3.1-K562 cells were combined with STI571, meanwhile its survival rate declined more slowly than that of K562 cell with STI571. In conclusion, P21(WAF) inhibits the proliferation of K562 cell, meanwhile slightly inhibits its apoptosis induced by STI571and decrease its sensitivity to STI571.
Subject(s)
Humans , Antineoplastic Agents , Pharmacology , Apoptosis , Genetics , Base Sequence , Benzamides , Blotting, Western , Cell Cycle , Genetics , Cell Proliferation , Cloning, Molecular , Cyclin-Dependent Kinase Inhibitor p21 , Genetics , Metabolism , Imatinib Mesylate , K562 Cells , Leukemia, Myelogenous, Chronic, BCR-ABL Positive , Genetics , Metabolism , Pathology , Molecular Sequence Data , Piperazines , Pharmacology , Protein-Tyrosine Kinases , Pyrimidines , Pharmacology , TransfectionABSTRACT
<p><b>OBJECTIVE</b>To investigate the differential expression of RPL6/Taxreb107 between drug-resistant gastric cancer cell line SGC7901/ADR and gastric cancer cell line SGC7901 as well as its correlation with multiple-drug resistance (MDR) in gastric cancer cells.</p><p><b>METHODS</b>Total RNA was extracted from SGC7901 and SGC77901/ADR, with internal control RT-PCR, Northern blot, gene cloning and expression, construction of eukaryotic expression vector, gene transfection by electroporation. The accumulation and retention of ADR in transiently transfected cell was detected by flow cytometry.</p><p><b>RESULTS</b>The internal control RT-PCR and Northern blot showed high RPL6/Taxreb107 expression in SGC7901/ADR cell line. Sense and antisense eukaryonic expression vectors demonstrated by double enzyme digestion were successfully transfected into gastric cancer cell line SGC7901 and SGC7901/ADR respectively by electroporation. The accumulation and retention of ADR detected 48 hours after transfection showed that RPL6 gene had shown effect on drug resistance in gastric cancer cell.</p><p><b>CONCLUSION</b>The high expression of RPL6/Taxreb107 in drug resistant gastric cancer cell shows its correlation with multiple-drug resistance in gastric cancer.</p>
Subject(s)
Humans , DNA-Binding Proteins , Metabolism , Drug Resistance, Multiple , Physiology , Drug Resistance, Neoplasm , Physiology , Statistics as Topic , Stomach Neoplasms , Pathology , Tumor Cells, CulturedABSTRACT
The purpose of this work was to investigate the effects of niflumic acid (NFA), a chloride channel blocker, on the proliferation of human hepatoma cell line (HHCC). Cell proliferation was analyzed by cell count and MTT assay. Cell cycle analysis was carried out by flow cytometry. [Ca(2+)](i) was determined by laser scanning confocal system. It was found that NFA decreased significantly the cell number and the MTT optical density (OD) of HHCC cells, and that the OD value was reversed after washout of NFA. Compared with control, NFA blocked cell cycle progression in G(1) phase. Extracellular application of NFA (100 micromol/L) induced a rapid decrease in [Ca(2+)](i). These findings demonstrate that blockage of chloride channels by NFA induces growth arrest of HHCC in G(1) phase, which may be due to the inhibition of Ca(2+)/CaM-dependent signaling pathways.