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Novel Candidate Drugs That Target Cccdna of
HBV
Yoshiki Murakami1, Michiyo Hayakawa1, Saori Itami-
Matsumoto1, Mari Ando1, Yutaka Yata1,2, Masaru Enomoto1,
Akihiro Tamori1, Norifumi Kawada1, Takashi Honda3,
Yoshihiko Yano4, Mitsuo Iwadate5 and Hideaki Umeyama5,
(1)Department of Hepatology, Osaka City University, (2)
Department of Gastroenterology, Hanwa Sumiyoshi General
Hospital, (3)Department of Gastroenterology and Hepatology,
Nagoya University School of Medicine, (4)Department
of Gastroenterology, Kobe University, (5)Department of
Biological Science, Chuo University
Background: Antiviral drugs that treat chronic hepatitis
B with nucleos(t)ide analogues are considered effective.
Although the frequency of emerging escape mutant viruses
has decreased, most drugs of this class frequently result
in viral relapse after cessation of therapy. Persistent viral
infections require the presence of the viral genome in
the infected cell in a stable form that is not lost during cell
division. For hepadnaviruses, the viral genome persists in the
nucleus as covalently closed circle (ccc) DNA. Sp1, a group
of transcription factors that bind specifically to DNA, regulates
the expression of the Hepatitis B virus X (HBx) gene. The
HBx protein affects the epigenetic function of nuclear HBV
cccDNA via several nuclear transcription factors. Moreover
cyclin D2 regulated HBV replication by enhancing the activity
of HBV core and Sp1 promoters. To develop more efficient
drugs to treat chronic hepatitis B, it is necessary to focus on
the viral replication process, excluding reverse-transcription.
We aimed to identify low molecular compounds that suppress
the transcription of cccDNA. Methods: Fifteen chemical
compounds for Sp1 inhibitors were chosen from a library
of chemical compounds (AKos GmbH, Steinen, Germany)
using in silico screening. PXB cells (Phoenix bio, Hiroshima,
Japan) with HBV infection were cultured. The medium was
changed every five days and one chemical compound was
added each time the medium was changed. The quantities
of HBVDNA in the medium and cccDNA in the nucleus were
measured using real-time PCR. The human albumin content
in the medium was detected using the Human albumin
ELISA quantitation kit (Bethyl, Montgomery, AL, USA).
Results: Four of the 15 compounds were able to suppress
viral replication without cytotoxicity. The level of HBVDNA
treated with candidate No.15 (1-[3-(4-tert-butylcyclohexyl)
oxy-2-hydroxypropyl]-2,2,6,6-tetramethylpiperidin-4-ol) is
the same as that of entecavir (ETV). Anti-HBV effect of this
chemical compound is dose-depending manner and the IC
50 is 66 nM. Moreover, candidate No.15 was able to reduce
significantly the expression level of ccc DNA, as compared
to ETV (p<0.05). Conclusion: In this study, we developed
novel anti-viral candidates that decreased viral replication
by targeting cccDNA. Identifying candidate for controlling
nuclear transcription factor facilitates development of novel
medicines that combine novel anti-viral drugs and nucleos(t)
ide analogues for HBV treatment作者: StephenW 时间: 2018-10-17 18:54
409哟西
