Inhibition of HIV-1 replication by an anti-tat hammerhead ribozyme.

Tat is a virally expressed regulatory protein involved in the replication of HIV-1, the etiological agent of AIDS. To investigate the effect of tat inhibition on HIV replication, we constructed a retroviral vector to express an anti-tat hammerhead ribozyme as part of the 3' untranslated region of beta-galactosidase transcripts. Initial testing of this vector in tat-expressing COS-7 cells reduced tat activity by 85-95% as measured by tat-dependent CAT assays. Amphotropic and HIV-pseudotyped retroviral particles generated with this vector were used in HIV challenge experiments to determine the ability of this reagent to control HIV replication. CD4(+) peripheral blood lymphocytes (PBLs) stably transduced with this vector were subsequently challenged with HIV. These cells were able to resist HIV infection for up to 20 days as measured by cell death and reverse transcriptase activity. These data yield proof of principle that a pseudotyped retroviral vector can target and deliver a protective ribozyme to CD4(+) cells.

Treatment of human prostate cancer cells with dolastatin 10, a peptide isolated from a marine shell-less mollusc.

BACKGROUND: Dolastatin 10 is an anticancer peptide isolated from the sea hare, Dolabela auricularia, which is currently in phase I trials. METHODS: The effects of dolastatin 10 on the DU-145 human prostate cancer cell line were studied both in tissue culture and in athymic nude mice. In tissue culture, after dolastatin 10 treatment, cell cycle kinetics were measured using propidum iodide, apoptosis was estimated using the TUNEL assay, and tubulin architecture studied by direct immunofluorescence. RESULTS: At concentrations of 1 nM (IC50 = 0.5 nM), dolastatin 10 completely inhibited the growth in tissue culture of human prostate cancer DU-145 cells. Growth inhibition was correlated with the arrest of these cells in G2/M and alpha-tubulin depolymerization. In athymic mice at a dose of 5 micrograms every 4 days i.p., dolastatin 10 blocked the diaphragmatic invasion of DU-145 tumor cells. CONCLUSIONS: Dolastatin 10 is a novel marine-derived compound with activity in the treatment of human prostate cancer in animals. The mechanism of action of this agent involves tubulin depolymerization but not the induction of apoptosis.

Stable in vivo gene transduction via a novel adenoviral/retroviral chimeric vector.

Gene therapy to correct defective genes requires efficient gene delivery and long-term gene expression. The available vector systems have not allowed the simultaneous achievement of both goals. We have developed a chimeric viral vector system that incorporates favorable aspects of both adenoviral and retroviral vectors. Adenoviral vectors induce target cells to function as transient retroviral producer cells in vivo. The progeny retroviral vector particles are then able to stably transduce neighboring cells. In this system, the nonintegrative adenoviral vector is rendered functionally integrative via the intermediate generation of a retroviral producer cell. The chimeric vectors may allow realization of the requisite goals for specific gene-therapy applications.

Adenoviral/retroviral vector chimeras: a novel strategy to achieve high-efficiency stable transduction in vivo.

Gene therapy to correct defective genes requires efficient gene delivery and long-term gene expression. Realization of both goals with available vector systems has so far not been achieved. As a novel approach to solve this problem, we have developed a chimeric viral vector system that exploits favorable aspects of both adenoviral and retroviral vectors. In this schema, adenoviral vectors induce target cells to function as transient retroviral producer cells in vivo. The progeny retroviral vector particles can then effectively achieve stable transduction of neighboring cells. In this system, the nonintegrative adenoviral vector is rendered functionally integrative via the intermediate generation of an induced retroviral producer cell. Such chimeric vectors may now allow realization of the requisite goals for specific gene therapy applications.

Effects of chrysotherapy on cell mediated immune response.

Auranofin (AF) differs significantly from gold sodium thiomalate (GSTM) in formulation, i.e., aurous gold is stabilized by dual sulfur and phosphorus ligands, hydrophobic rather than hydrophilic characteristics, and lack of ionic charge. These attributes facilitate: oral absorption of AF, plasma membrane penetration, increase in intracellular lymphocyte gold concentration; and perhaps thereby influence lymphocyte function. AF treated subjects recorded prompt and sharp declines in mitogen-induced lymphoproliferative response (LMR) greater than 80%; suppressed response to skin testing with dinitrochlorobenezene (DNCB) in 11 of 14 subjects; and blebbing of lymphocyte membranes by scanning electron microscopy. In contrast, lymphocytes from a matched group of GSTM treated subjects recorded later onset and less suppression of LMR; normal response to DNCB skin testing; and did not manifest membrane blebbing. Accordingly, the therapeutic action of AF on immune response was observed in the 16 subjects receiving 6 mg/d of an average of 45 weeks to effect primarily cell mediated rather than humoral immune response when compared with a matched group of GSTM treated patients.

Assessment of immune response during chrysotherapy. Comparison of gold sodium thiomalate vs. auranofin.

Auranofin (AF) differs significantly from gold sodium thiomalate (GST) in formulation, i.e., aurous gold is stabilized by dual sulfur and phosphorus ligands, has hydrophobic rather than hydrophilic characteristics, and lacks ionic charge. These attributes facilitate: oral absorption of AF, plasma membrane penetration, increase in intracellular lymphocyte gold concentration and perhaps thereby influence lymphocyte function. AF therapy was observed to affect primarily T rather than B lymphocyte function in 16 RA subjects receiving 6 mg of AF per day for an average of 45 weeks (range 20-74 weeks) compared with GST-treated RA subjects. Lymphocytes from AF-treated subjects manifested prompt and sharp declines in mitogen-induced lymphoproliferative response (LPR); suppressed response to skin testing with dinitrochlorobenzene (DNCB); and blebbing of lymphocyte membranes as shown by scanning electron microscopy. Suppression of LPR with AF was approximately 60% after the first week and 80% after 20 weeks of therapy, contrasting with 0% and 30% for the respective intervals in GST-treated subjects. DNCB skin testing of AF patients, indicated 11 of 14, failed to respond, whereas all GST patients responded. Local or systemic fungal, bacterial and/or opportunistic infections were not encountered. The effect of AF on B cell effector function, e.g., suppression of immunoglobulins and rheumatoid factor titer, was less marked when contrasted with GST therapy in RA subjects, as previously reported.