Synthesis and anti-HIV Activity of a Series of 2-Indolinones and Related Analogues

A novel series of 2-indolinones with in vitro anti-HIV (human immunodeficiency virus) activity is described. Two structurally related compounds, 1, 3,3-(4- N-methyl-1,2,5,6-tetrahydropyridylmethyl)-1- phenyl-2-indolinone, and 2, its 4- N-methylpiperidinylmethyl analogue (Fig. 1), formed the basis of a structure-activity study. The synthesis of approximately 50 analogues and their respective activities vs. HIV are presented. Both 1 and 2 were effective inhibitors of HIV(IIIb) in cell protection assays with IC90 values of 4.4 and 14.9μM (2.2 and 7.9μg ml−1), respectively. In the same concentration range, 1 and 2 also inhibit syncytia formation. These compounds represent a novel class of anti-HIV agents which appear to act by inhibiting virus-dependent cell fusion.

Constitutive expression of chimeric neo-Rev response element transcripts suppresses HIV-1 replication in human CD4+ T lymphocytes

We have previously reported that chimeric neomycin phosphotransferase (neo)-Rev response element (RRE) transcripts suppress the function of the human immunodeficiency virus type 1 (HIV-1) Rev trans-activator protein in HeLa cells. In an extension of these experiments, human CD4+ CEM cells (G418-resistant cell populations and clonal isolates) stably expressing chimeric neo-RRE genes (2, 3, or 6 RRE copies) were generated using retroviral-mediated gene transfer. The transduced CEM clones were infected with the HIV-1 HTLVIIIB isolate and the following three phenotypes were observed: (i) the transduced CEM cells were readily infected with HIV-1 indistinguishable from the control CEM cells; (ii) the appearance of HIV-1 replication markers was significantly delayed; (iii) no signs of HIV-1 replication were detectable although proviral HIV-1 DNA sequences could be detected in these cells. Furthermore, HIV antigen expression was limited in neo-resistant CEM cell populations inoculated with the HIV-1 HTLVIIIB isolate. Only 10% of the CEM-pX17-3xRRE cells and 20% of the CEM-pX17-2xRRE cells displayed HIV-1 antigens 43 days after challenge and had retained CD4 surface expression on 47% and 64% of the cells, respectively. In sharp contrast, 80% of the CEM-pX17 or the CEM-pX17-6xRRE cells expressed HIV-1 antigens but no CD4 antigens were detectable in these cultures. These results clearly indicate that RRE decoys could be developed into an effective somatic gene therapy approach against HIV-1 induced acquired immunodeficiency syndrome (AIDS).

Whole cell assays in screening for biologically active substances

This past year has seen a number of new developments in recombinant cell based assays. Lead compounds are beginning to be identified using mechanism-based whole cell assays to discover inhibitors of cellular processes, such as transactivation and signaling. These assays offer advantages for many targets over subcellular assay systems with purified macromolecules.