Prime-boost vaccination with recombinant mumps virus and recombinant vesicular stomatitis virus vectors elicits an enhanced human immunodeficiency virus type 1 Gag-specific cellular immune response in rhesus macaques.

Intramuscular inoculation of rhesus macaques with one or more doses of recombinant vesicular stomatitis virus (rVSV) expressing human immunodeficiency virus type 1 (HIV-1) Gag (rVSVgag) typically elicits peak cellular immune responses of 500 to 1,000 gamma interferon (IFN-gamma) enzyme-linked immunospots (ELISPOTS)/10(6) peripheral blood lymphocytes (PBL). Here, we describe the generation of a novel recombinant mumps virus (rMuV) expressing HIV-1 Gag (rMuVgag) and measure the Gag-specific cellular immune responses detected in rhesus macaques following vaccination with a highly attenuated form of rVSV expressing HIV-1 Gag (rVSVN4CT1gag1) and rMuVgag in various prime-boost combinations. Notably, peak Gag-specific cellular immune responses of 3,000 to 3,500 ELISPOTS/10(6) PBL were detected in macaques that were primed with rMuVgag and boosted with rVSVN4CT1gag1. Lower peak cellular immune responses were detected in macaques that were primed with rVSVN4CT1gag1 and boosted with rMuVgag, although longer-term gag-specific responses appeared to remain higher in this group of macaques. These findings indicate that rMuVgag may significantly enhance Gag-specific cellular immune responses when administered with rVSVN4CT1gag1 in heterologous prime-boost regimens.

Enzymatic kinetic resolution of piperidine atropisomers: synthesis of a key intermediate of the farnesyl protein transferase inhibitor, SCH66336.

The resolution of secondary amines via enzyme-catalyzed acylation is a relatively rare process. The kinetic resolution of a series of intermediates of SCH66336 (1), by either enzymatic acylation of the pendant piperidine (4, 5) or hydrolysis of the corresponding carbamate 3, was investigated. In the case of 4, the molecule exists as a pair of enantiomers due to atropisomerism about the exocyclic double bond. The enzymatic acylation of (+/-)-4 was optimized in terms of acylating agent, solvent, and moisture content. The use of lipase, Toyobo LIP-300, and trifluoroethyl isobutyrate as acylating agent resulted in isobutyrylation of the (+)-enantiomer, which is easily separated from the unwanted (-)-4. Hydrolysis of the isobutyramide 6c yielded the desired (+)-4 in high enantiomeric excess. (-)-4 may be recovered from the resolution step, racemized, and resubjected to enzymatic acylation to increase material throughput.

5-Ethoxy-2'-deoxyuridine, a novel substrate for thymidine phosphorylase, potentiates the antitumor activity of 5-fluorouracil when used in combination with interferon, an inducer of thymidine phosphorylase expression.

Clinical studies have demonstrated that the combination of 5-fluorouracil (FUra) and IFN-alpha has activity in the treatment of advanced colorectal cancer. Treatment of human colon carcinoma cells with IFN caused a 5-fold increase in the level of thymidine phosphorylase (TP) mRNA and an 8-fold increase in TP enzyme activity. Since TP catalyzes the first step in the direct conversion of FUra to deoxyribonucleotides, its induction by IFN is a potential biochemical mechanism for the modulation of the antitumor activity of FUra. In contrast to the activity measured in cell extracts, however, thymine utilization by intact cells was increased less than 2-fold by IFN, suggesting that the metabolic activation of FUra by TP in the IFN-treated cells was similarly suboptimal. This was likely due to a rate-limiting amount of cosubstrate for TP, and in this study, a series of 5-substituted 2'-deoxyuridine analogues were synthesized and tested as potential deoxyribose donors for TP. One of the compounds, the novel pyrimidine analogue 5-ethoxy-2'-deoxyuridine (EOdU), was found to be a substrate for the transferase reaction of TP, to have little or no direct cytotoxicity, to selectively increase the cellular levels of 5-fluoro-dUMP, to enhance the inhibitory effect of FUra on thymidylate synthase activity, and to potentiate the cytotoxicity of FUra and IFN in human colon carcinoma cells. EOdU was tested in vivo against HT-29 cells grown as xenografts in nude mice. The combination of EOdU+FUra+IFN-alpha 2a produced tumor regressions and a significantly greater delay in tumor growth when compared to FUra+IFN-alpha 2a, FUra+EOdU, or FUra or IFN used alone; tumors were 72% smaller in the EOdU+FUra+IFN-alpha 2a-treated animals compared to the saline control group. A comparable antitumor effect was also found when a related nucleoside analogue, 5-propynyloxy-2'-deoxyuridine, was used with FUra+IFN, and it also showed modulating activity when used with only FUra. The antitumor activity of the three agent combination (nucleoside+IFN+FUra) was comparable to that of a higher dose of FUra used alone, but it was substantially less toxic to the animals than the higher dose of FUra, indicating that the modulating agents improved the therapeutic index of FUra.(ABSTRACT TRUNCATED AT 400 WORDS)

Synthesis, absolute configuration, and enantioselectivity of antiretroviral effect of (R)-(-)- and (S)-(+)-cytallene. Lipase-catalyzed enantioselective acylations of (+/-)-N4-acylcytallenes.

Enantioselectivity of acylations of (+/-)-cytallene (1b), (+/-)-N4-acetylcytallene (11a), (+/-)-N4-benzoylcytallene (11b), and (+/-)-N4-(9-fluorenylmethoxycarbonyl)cytallene (11c) using vinyl butyrate or acetate catalyzed by lipases in organic solvents was investigated. Reactions with 1b, 11a, and adenallene (1a) did not display a high enantioselectivity but all resulted in a predominant acylation of the (-)-enantiomers. Application of the Lowe-Brewster rule led to a tentative assignment of the R-configuration to all acylated products. Studies of the time course of acylation of (+/-)-N4-benzoylcytallene (11b) in chloroform, tetrahydrofuran (THF), tetrahydropyran (THP), tetrahydrothiophene (THT), and dioxane with lipase PS30 and/or AK showed that the reaction in THF catalyzed by lipase AK was the most promising for resolution of 11b. Indeed, a large-scale acylation afforded, after separation and deprotection of intermediates 3e and 10d, (+)- and (-)-cytallene (3c and 2b) in high yield and enantioselectivity. Acylation of 11c in THF led also to formation of 3c and 2b in high enantioselectivity. Single crystal X-ray diffraction established the S-configuration of (+)-cytallene (3c), thus confirming the assignment made on the basis of Lowe-Brewster rule. An improved large-scale synthesis of (+/-)-cytallene (1b) is also described. The R-enantiomer 2b inhibited the replication of a primary human immunodeficiency virus (HIV-1) isolate in phytohemagglutinin-activated peripheral blood mononuclear cells (PHA-PBM) with IC50 0.4 and IC90 1.7 microM. (+/-)-Cytallene (1b) exhibited IC50 0.8 and IC90 3.4 microM. Both compounds completely suppressed replication of HIV-1 at 10 microM with no detectable cytotoxicity. The S-enantiomer (3c) was inactive.

(R)-(-)- and (S)-(+)-adenallene: synthesis, absolute configuration, enantioselectivity of antiretroviral effect, and enzymic deamination.

Synthesis of optically pure (-)- and (+)-adenallene 2 and 3 is described. Racemic adenallene (1a) was subjected to deamination with adenosine deaminase monitored by HPLC using a Chiralcel CA-1 column to give (-)-adenallene (2) and (+)-hypoxallene (4). The latter compound was converted to acetate 5. The reaction of 5 with trifluoromethanesulfonic anhydride and pyridine followed by ammonolysis furnished acetate 6 or (+)-adenallene (3) depending on the solvent used in the last step. Acetate 5 was smoothly transformed to the 6-chloro derivative 7, but an attempted ammonolysis led only to racemization and decomposition. Single crystal X-ray diffraction established the R-configuration of (-)-enantiomer 2. The latter forms a pseudosymmetric dimer in the lattice with the adenine moiety in an anti-like conformation. The torsional angles of the allenic bonds show departures from 90 degrees (91 and 97 degrees, respectively) and rotameric preference of the hydroxymethyl groups is different in both molecules of the dimer. The R-enantiomer 2 inhibited the replication and cytopathic effect of human immunodeficiency virus (HIV-1) in ATH8 cell culture with an IC50 of 5.8 microM, whereas the S-enantiomer 3 was less active (IC50 > 200 microM). The enantioselectivity of the anti-HIV effect is significantly lower than that of 2',3'-dideoxyadenosine. Kinetics of deamination of R- and S-enantiomers 2 and 3 catalyzed by adenosine deaminase gave the following parameters: Km values of S-form 3 and R-form 2 were 0.41 and 0.52 mM with Vmax being 530 and 18.5 mumol/min, respectively [corrected]. Again,, a much lower level of enantioselectivity of deamination was observed than that of D- and L-adenosine. These results indicate (i) different enantioselectivity of enantiomers 2 and 3 as HIV inhibitors and adenosine deaminase substrates and (ii) both R- and S-enantiomers 2 and 3 can function as nucleoside analogues with varied enantioselectivity for different enzymes or receptors.