Inhibition of hepatitis B virus by a novel L-nucleoside, 2'-fluoro-5-methyl-beta-L-arabinofuranosyl uracil

Abstract

2'-Fluoro-5-methyl-beta-L-arabinofuranosyl uracil (L-FMAU) was discovered to have potent antiviral activity against hepatitis B virus (HBV). L-FMAU was more potent than its D-enantiomer and produced dose-dependent inhibition of the viral DNA replication in 2.2.15 cells (human HepG2 cells with the HBV genome), with a 50% inhibitory concentration of 0.1 microM. There was no inhibitory effect on HBV transcription or protein synthesis. In the 2.2.15 cell system, L-FMAU did not show any toxicity up to 200 microM, whereas the D-enantiomer was toxic, with a 50% inhibitory concentration of 50 microM. Repeated treatments of HepG2 cells with L-FMAU at a 1 microM concentration for 9 days did not result in any decrease in the total mitochondrial DNA content, suggesting that a mode of toxicity similar to that produced by 2',3'-dideoxycytidine is unlikely. Also at concentrations as high as 200 microM, L-FMAU did not adversely affect mitochondrial function as determined by lactic acid production by L-FMAU-treated hepatoma cells. L-FMAU was metabolized in the cells to its mono-, di-, and triphosphates, A dose-dependent inhibition of HBV DNA synthesis by L-FMAU triphosphate was observed in the DNA polymerase assays with isolated HBV particles, suggesting that the mode of action of this compound could involve viral polymerase. However, L-FMAU was not incorporated into the cellular DNA. Considering the potent inhibition of the viral DNA synthesis and the nontoxicity of L-FMAU towards the host DNA synthetic machinery, this compound should be further explored for development as asn anti-HBV drug.

High-dose clevudine impairs mitochondrial function and glucose-stimulated insulin secretion in INS-1E cells

“…Commonly used antiviral therapies are nucleoside analog reverse transcriptase inhibitors (NRTIs) including entecavir, lamivudine, and telbivudine. NRTIs undergo intracellular and intramitochondrial phosphorylation into active triphosphates that are capable of inhibiting HIV reverse transcriptase (RT) [2]. However, these drugs have side effects such as lipodystrophy, neuropathy, myopathy, and liver steatosis, all of which are related to mitochondrial toxicity.…”

“…Clevudine (1-(2-deoxy-2-fluoro-β-L-arabinofuranosyl) thymine) is an NRTI that exhibits potent and sustained antiviral activity against HBV with weaker effects on mitochondrial structure and function compared to those of other NRTIs [2,5]. However, long-term therapy for more than one year results in the development of considerable drug resistance and skeletal myopathy [6-9].…”

Hepatitis B virus reverse transcriptase – Target of current antiviral therapy and future drug development

“…Clevudine is a thymidine analog approved for HBV treatment in the Philippines and South Korea (Balakrishna Pai et al, 1996; Chu et al, 1995; Jang et al, 2011; Korba et al, 2006). It was shown, after cessation of treatment, to maintain suppression of HBV replication over 6 months (Lee et al, 2006; Peek et al, 2001), very unusual for a polymerase inhibitor.…”

Design and Evaluation of Hepatitis B Virus Inhibitors

“…This compound inhibits HBV replication by greater than 90% in an HBV producing cell line (2.2.15) [16,17] and in duck HBV model (DHBV) in vivo [18] but is associated with hepatotoxicity [19]. In a phase 1/II clinical trials adefovir dipivoxyl 13, an acyclic phosphorylated purine nucleoside, shows that patients exhibited a 97% reduction in HBV DNA levels after of 28 -day of treatment with once -aOther β-L-nucleoside analogs such as β-L-FMAU 4 [9] exhibit activity against HBV with no detectable effect on mithochondria synthesis [10]. The 2',3'-dideoxy-2',3'-didehydro analogs of β-Lcytidine 5 and its 5-fluoro derivatives 6 were also reported to exhibit potent activity against HBV [11].…”

“…0,2 [25,87,139] 0,05-0,7-1,2 [25,55,59,139] yes [24] no Phase III [20,152] 2'CDG <0,1 [18] 0,05-0,1 [13,16,21] yes [18,19,116] no no β-D-FIAU 3 0,028 [61] 0, 9-10 [21,61] no yes [132] High toxicity [158] β-L-FMAU 4 0,1 [9,10] yes [86] yes [132] Planned [References] to estimate mitochondrial cytotoxicity [67], and are less used.…”