Bisheteroarylpiperazine reverse transcriptase inhibitor in combination with 3'-azido-3'-deoxythymidine or 2',3'-dideoxycytidine synergistically inhibits human immunodeficiency virus type 1 replication in vitro

Abstract

Bisheteroarylpiperazine compounds are nonnucleoside reverse transcriptase inhibitors of human immunodeficiency virus type 1 (HIV-1). To provide a rationale for combination therapy with a second-generation bisheteroarylpiperazine, we investigated the effect of U-90152 in combination with 3'-azido-3'-deoxythymidine (AZT) or 2',3'-dideoxycytidine (ddC). HIV-1-infected cells were cultured in the presence of test compounds, and drug effects on p24 core antigen production were measured by an enzyme-linked immunosorbent assay. In a CD4+ T-cell line (H9) infected with HIV-1IIIB, the 501% effective concentrations for U-90152, AZT, and ddC were 6.0, 80.4, and 31.8 nM, respectively. In human peripheral blood mononuclear cells infected with the molecularly cloned clinical isolate HIV-lJRCSF, the 50%o effective concentrations for U-90152, AZT, and ddC were 5.3, 5.9, and 25.0 nM, respectively. Over a range of drug concentrations (U-90152 and AZT at 0.3, 1, 3, 10, and 30 nM; ddC at 3, 10, 30, and 100 nM), U-90152 in combination with AZT or ddC synergistically inhibited the replication of a laboratory-adapted strain and a clinical isolate of HIV-1.The bisheteroarylpiperazine (BHAP) class of compounds has been shown to inhibit the reverse transcriptase (RT) of human immunodeficiency virus type 1 (HIV-1) and block HIV-1 replication in culture cells (1,3,7,8,28,33). The BHAPs belong to a structurally diverse group of compounds known as the nonnucleoside RT inhibitors. These compounds inhibit the HIV-1 RT by binding to a common region of the enzyme away from the substrate binding site (8,12,33). In contrast, nucleoside analog inhibitors, such as 3'-azido-3'-deoxythymidine (AZT), 2',3'-dideoxyinosine, and 2',3'-dideoxycytidine (ddC), mimic the normal deoxynucleotide triphosphate substrate for RT and thus act as chain terminators during proviral synthesis (31). Other nonnucleoside RT inhibitors include dipyridodiazepinones (nevirapine) (18, 23), pyridinones (L-697,661) (12), thiobenzimidazolone compounds (TIBO Ro82150) (25), and the more recently reported TSAO [2',5' -bis-O-(tert-butyl-dimethylsilyl)-3' -spiro-5"-(4"-amino-1",2"-oxathiole-2",2"-dioxide)pyrimidine] and HEPT {1-[(2-hydroxyethoxy)methyl]-6-(phenylthio)thymine} compounds (2, 32).Drug

Non-nucleoside Inhibitors of HIV-1 Reverse Transcriptase Inhibit Phosphorolysis and Resensitize the 3′-Azido-3′-deoxythymidine (AZT)-resistant Polymerase to AZT-5′-triphosphate

“…Despite many studies devoted to this topic, the molecular mechanism underlying the antiviral synergy of combinations of reverse transcriptase inhibitors is in most cases unknown. The synergistic inhibition of HIV replication in cell culture has been reported for many combinations of nucleosidic and NNRTI inhibitors including, among others, bis(heteroaryl)piperazine derivates (29), pyridinone derivates (30), nevirapine (13), HEPT derivates (14), TIBO derivates (15,31), or canalolide A (16). However, other studies have shown that the same combinations showed no synergy in inhibiting RT activity in vitro (17)(18)(19)(20)(21).…”

Synergistic Inhibition of Human Immunodeficiency Virus Type 1 Replication in Vitro by Two- and Three-Drug Combinations of Delavirdine, Lamivudine and Zidovudine

“…A synergistic antiviral effect in vitro has also been reported for two-drug combinations involving ZDV and several other NNRTls including DLV, pyridinone L-697,639 and nevirapine (Chong et al, 1994;Richman et al, 1991;Goldman et al, 1991). Separately, Balzarini et al (1996) reported that when combined with 3TC, several NNRTls, including DLV, more readily suppress viral 'breakthrough', and may delay the emergence of resistant virus.…”

“…This is equivalent to 70% of the peak viral titre achievable on day 7 post-infection. PBMC antiviral assays were set up as described previously (Chong et a!., 1994). The percentage inhibition of HIV replication on day 5 of treatment was determined by comparing HIV p24 antigen levels in the supernatant of infected cells treated with inhibitor versus supernatant from the control cultures without compound.…”

“…HIV-1 JR _ CSF was selected because it replicates in PBMC but has not been adapted to replicate in cell lines (Koyanagi et a!., 1987). Stock viruses ofHIV-1JR_CSF were harvested as culture supernatant from infected primary human PBMC culture as previously described (Chong et a!., 1994).…”

“…We have previously reported that DLV is synergistic when used in two-drug combinations in vitro with NRTIs 334 ZDV or 4-amino-1-p-D-2',3'-dideoxyribofuranosyl-2-(lH)-pyrimidinone (zalcitabine; ddC), and in three-drug combination involving ZDV and 2',3'-dideoxyinosine (didanosine; ddI) (Chong et al, 1994;Chong & Pagano, 1997). Here we describe and compare the antiviral effects of two-and three-drug combinations of DLV, 3TC and ZDV in acutely infected peripheral blood mononuclear cells (PBMC).…”