Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0017636 (glioblastoma)
 18,345 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Recombinant purified Nef protein of HIV-1, as well as Nef protein derived from extracts of permanently HIV-1 infected glioblastoma cells and monocytes, are specifically cleaved by the HIV-1 protease. Nef cleavage products in cellular extracts treated with protease showed identical molecular weights as those obtained by digestion of purified Nef with recombinant HIV-1 protease. Since cellular extracts were prepared by detergent and mechanical lysis it cannot be excluded that physiological cytoplasmic conditions were altered. The lack of Nef cleavage by endogenous HIV-1 protease in infected cells might be due to low concentrations of viral protease and the presence of Gag precursor molecules as natural substrate. Using a panel of monoclonal antibodies two cleavage fragments of 19 kDa and 8 kDa were defined. The cleavage site was located by microsequencing between amino acid 57 and 58 (AW*LEAQEEEEVGF). The conserved cleavage motif within HIV-1 Nef suggests a potential biological function of Nef processing.
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PMID:Cleavage of recombinant and cell derived human immunodeficiency virus 1 (HIV-1) Nef protein by HIV-1 protease. 783 26

In vivo imaging of endogenously expressed mammalian proteases has been useful for the detection of cancer and preneoplastic lesions, for staging of inflammatory and autoimmune diseases, and for testing the efficacy of novel protease inhibitors. Here we report on the synthesis of a novel imaging probe that is specific for HIV-1 protease (PR). The probe was designed to be biocompatible, i.v. injectable, and detectable by fluorescence imaging. Human Gli36 glioblastoma cells infected with an human simplex virus amplicon vector expressing HIV-1PR showed specific fluorescence activation, an effect that could be inhibited by the HIV-1PR inhibitor, indinavir. The transfer of the HIV-1PR marker gene could be detected in vivo after intratumoral delivery of the human simplex virus-amplicon vector. These results are the first proof of principle that viral proteases can directly be imaged in vivo. These findings may be directly applicable in using viral protease expression as a transgene marker in tumor therapy and may have implications in testing the efficacy of HIV-1PR inhibitors in vivo.
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PMID:In vivo imaging of HIV protease activity in amplicon vector-transduced gliomas. 1472 34

Immune reconstitution might not be the only factor contributing to the low prevalence of microsporidiosis in human immunodeficiency virus (HIV)-infected patients treated with protease inhibitors, as these drugs may exert a direct inhibitory effect against fungi and protozoa. In this study, we developed a cell culture-quantitative PCR assay to quantify Encephalitozoon intestinalis growth in U-373-MG human glioblastoma cells and used this assay to evaluate the activities of six HIV aspartyl protease inhibitors against E. intestinalis. A real-time quantitative PCR assay targeted the E. intestinalis small-subunit rRNA gene. HIV aspartyl protease inhibitors were tested over serial concentrations ranging from 0.2 to 10 mg/liter, with albendazole used as a control. Ritonavir, lopinavir, and saquinavir were able to inhibit E. intestinalis growth, with 50% inhibitory concentrations of 1.5, 2.2, and 4.6 mg/liter, respectively, whereas amprenavir, indinavir, and nelfinavir had no inhibitory effect. Pepstatin A, a reference aspartyl protease inhibitor, could also inhibit E. intestinalis growth, suggesting that HIV protease inhibitors may act through the inhibition of an E. intestinalis-encoded aspartyl protease. These results showed that some HIV protease inhibitors can inhibit E. intestinalis growth at concentrations that are achievable in vivo and that the real-time quantitative PCR assay that we used is a valuable tool for the in vitro assessment of the activities of drugs against E. intestinalis.
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PMID:Inhibitory activity of human immunodeficiency virus aspartyl protease inhibitors against Encephalitozoon intestinalis evaluated by cell culture-quantitative PCR assay. 1591 34