Important note: Information in this article was accurate in 1990. The state of the art may have changed since the publication date.
Antiretroviral effects of glycerophospholipid stereoisomers of AZT on HIV replication in HT4-6C cells.
Int Conf AIDS. 1990 Jun 20-23;6(1):186 (abstract no. Th.A.265). Unique Identifier : AIDSLINE ICA6/10026590 Kumar R; Richman DD; Hostetler KY; Vical Inc, San Diego, CA, USA
Abstract:
OBJECTIVE: Macrophages are an important target for anti-HIV therapies. We previously reported the synthesis of sn-3 phosphatidylAZT (pAZT), a phospholipid prodrug of azidothymidine (AZT, zidovudine) which was active in HIV-infected cells. pAZT can be targeted to macrophages in vivo. We wished to determine if the sn-1 derivative is also effective in HIV-infected cells since most of the cellular phospholipases are stereospecific for sn-3 phosphoglycerides. METHODS: We synthesized sn-1, sn-3, and racemic dipalmitoylglycerophosphoAZT from the corresponding isopropylidene glycerols by coupling with AZT-monophosphate followed by deblocking and acylation of the hydroxyls of glycerol with palmitic anhydride. Lipid vesicles containing 10 mole % of the pAZTs were incubated with HT4-6C cells after infection with the LAV-1BRU strain of HIV in a plaque reduction assay. RESULTS: sn-3 pAZT reduced plaque formation by 50% (ID50) at 2.1 uM versus 2.2 uM for the sn-1 derivative while racemic pAZT had an IC50 of 2.7 uM. None of these differences were statistically significant (n=3). CONCLUSIONS: Contrary to expectations, the sn-1 and sn-3 derivatives of pAZT were equally effective in reducing HIV replication of HT4-6C cells. This is a surprising result since most cellular phospholipases are thought to be specific for the sn-3 glycerophospholipids. Intact pAZTs have no intrinsic activity against HIV reverse transcriptase (RT). Therefore, the sn-1 pAZT must be degraded in the cell by enzymatic processes which are still uncharacterized before being converted to AZT-triphosphate, the inhibitor of RT.
Keywords: Cell Line Human HIV/*DRUG EFFECTS/PHYSIOLOGY Prodrugs/*PHARMACOLOGY Stereoisomers Virus Replication/*DRUG EFFECTS Zidovudine/*PHARMACOLOGY ABSTRACT 901230
M90C3532
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