Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: DrugBank:EXPT01586 (G418)
 2,237 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We have used antisense RNA technology to inhibit endogenous parathyroid hormone-related peptide (PTHRP) production in the established human keratinocyte cell line, HPK1A, in order to assess the role of PTHRP as a potential modulator of cell growth. Rat PTHRP cDNA was cloned into the replication defective retroviral vector pYN in an antisense orientation and a stable cell line (HPK1A-AS) was generated after infection by amphotropic virus and selection by the neomycin derivative, G418. Expression of the transfected antisense sequence was confirmed with an RNA sense probe for PTHRP. The effect of the retrovirally mediated gene transfer on the endogenous PTHRP transcript was examined with an RNA antisense probe which demonstrated an absence of the endogenous transcript in HPK1A-AS cells. A 1.6-kilobase transcript was, however, present in equivalent quantities in both uninfected HPK1A and pYN-infected (HPK1A-pYN) cells. Immunocytochemistry and assessment of PTHRP secretion into the medium using an NH2-terminal radioimmunoassay and a UMR 106 adenylate cyclase bioassay confirmed the absence of PTHRP in HPK1A-AS cells. Examination of the inhibition of PTHRP production on cell growth demonstrated a reduction in doubling time and an increase in [3H]thymidine incorporation. Cell cycle analysis showed an increase in the proportion of the cell population in the S phase (relative to G0/G1) in HPK1A-AS cells compared to HPK1A or HPK1A-pYN cells. These data, therefore, indicate that endogenous PTHRP acts as an effective inhibitor of cell growth in this keratinocyte model and that this action occurs, at least in part, by diminishing entry into the S phase of the cell cycle. Furthermore, the antisense RNA method is a potent one to evaluate the cellular actions of PTHRP.
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PMID:Enhanced growth of a human keratinocyte cell line induced by antisense RNA for parathyroid hormone-related peptide. 161 64

AIM:To construct Hsp90 antisense RNA eukaryotic expression vector, transfect it into SGC7901 and SGC7901/VCR of MDR-type human gastric cancer cell lines, HCC7402 of human hepatic cancer and Ec109 of human esophageal cancer cell lines, and to study the cell cycle distribution of the gene transected cells and their response to chemotherapeutic drugs.METHODS:A 1.03kb cDNA sequence of Hsp90beta was obtained from the primary plasmid phHSP90 by EcoR I and BamH I nuclease digestion and was cloned to the EcoR I and BamH I site of the pcDNA by T4DNA ligase and an antisense orientation of Hsp90beta expression vector was constructed. The constructs were transfected with lipofectamine and positive clones were selected with G418. The expression of RNA was determined with dot blotting and RNase protection assay, and the expression of Hsp90 protein determined with western blot. Cell cycle distribution of the transfectants was analyzed with flow cytometry, and the drug sensitivity of the transfectants to Adriamycin (ADR), vincrinstine (VCR), mitomycin (MMC) and cyclophosphamide (CTX) with MTT and intracellular drug concentration of the transfectants was determined with flow cytometry.RESULTS:In EcoR I and BamH I restriction analysis, the size and the direction of the cloned sequence of Hsp90beta remained what had been designed and the gene constructs were named pcDNA-Hsp90.AH-SGC7901, AH-SGC7901/VCR, AH-HCC7402 and AH-Ec109 cell clones all expressed Hsp90 anti-sense RNA. The expression of Hsp90 was down-regulated in AH-SGC7901, AH-SGC7901/VCR, AH-HCC7402 and AH-Ec109 cell clones. Cell cycle distribution was changed differently. In AH-SGC7901/VCR and AH-Ec109 cells, G(1) phase cells were increased; S phase and G(2) phase cells were decreased as compared with their parental cell lines. In AH-SGC7901 cell, G(1)phase cells were decreased, G(2) phase cells increased and S phase cells were not changed, and in AH-HCC7402 cells G(1), S and G(2) phase cells remained unchanged as compared with their parental cell lines. The sensitivity of AH-SGC7901, AH-SGC7901/VCR, AH-HCC7402 and AH-Ec109 to chemotherapeutic drugs, the sensitivity of AH-SGC7901/VCR to ADR, VCR, MMC and CTX the sensitivity of AH-HCC7402 to ADR and VCR, and the sensitivity of Ec109 to ADR, VCR and CTX all increased as compared with their parental cell lines. The mean fluorescence intensity of ADR in AH-SGC7901, AH-SGC7901/VCR, AH-HCC7402 and AH-Ec109 was also significantly elevated (P < 0.05).CONCLUSION: Down-regulation of Hsp90 could change cell cycle distribution and increase the drug sensitivity of tumor cells.
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PMID:Down-regulation of Hsp90 could change cell cycle distribution and increase drug sensitivity of tumor cells. 1181 30