1022-7954/01/3706- $25.00 © 2001
Russian Journal of Genetics, Vol. 37, No. 6, 2001, pp. 659–665. Translated from Genetika, Vol. 37, No. 6, 2001, pp. 803–810.
Original Russian Text Copyright © 2001 by Varga, Cheremnova, Ovchinnikova, Shapiguzov, Kudryavtseva, Morozova, Engelhardt, Lazarevich.
Hepatocyte nuclear factors (HNFs) contributing to
several families of regulatory proteins (HNF1, C/EBP,
HNF3, HNF4, and HNF6), are essential for regulation
of the expression of hepatocyte-speciﬁc genes and for
hepatocyte differentiation [1–3]. These factors are
liver-enriched but not restricted to this tissue. They
function in combination and often synergistically to
regulate liver-speciﬁc gene transcription. The transcrip-
tional hierarchy between the members of different fam-
ilies is still poorly understood, although the levels of
the expression of various HNFs are coordinated .
Little is known about the mechanisms responsible for
coordination of tissue-speciﬁc regulation and general
mechanisms of cell proliferation, their morphological
reorganization, and interaction with the microenviron-
One of the HNFs, HNF4
(below referred to as
HNF4) belongs to a superfamily of nuclear receptors
and, to our opinion, plays the key role in the expression
of the hepatocyte phenotype. This factor directly regu-
lates the expression of some serum proteins (tran-
sthyretin, transferrin, some apolipoproteins) [4, 5] and
activates the expression of the hepatocyte factor HNF1
. The binding sites for HNF1 were found in promot-
ers of many liver genes  including those for serum
albumin (SA) and alpha-fetoprotein.
Some evidence indicates that transcription regula-
tion of several liver-speciﬁc proteins does not exhaust
the HNF4 functions. A homozygous deletion of the
gene is lethal: it practically completely arrests
gastrulation leading to the death of the embryos as early
as on the tenth day of development [8–10]. In most ded-
ifferentiated hepatoma lines, no expression of the
HNF4 was detected . When exogenous HNF4 is
expressed in dedifferentiated hepatoma H5, the culti-
vated cells assumed the epithelial morphology as reex-
pression of E-cadherin and cytokeratin and the restoration
of cell–cell contacts and cell polarization [12, 13]. These
data suggest that HNF4 coordinates liver-speciﬁc gene
expression and epithelial morphogenesis.
Note that the role of HNF4 in hepatocarcinogenesis
is insufﬁciently studied and it could not be veriﬁed
under in vivo conditions because of the absence of an
adequate model. The necessity of this protein for the
establishment of the epithelial phenotype was demon-
strated using the H5 hepatoma cell culture, which
passed through numerous passages in vitro.
We have recently developed a novel experimental
system consisting of the highly differentiated slow-
growing hepatocarcinoma (sgHCC), the dedifferenti-
ated fast-growing variant (fgHCC) derived from the
former, and the fgHCC cell culture .
The abrupt progression of fgHCC beginning from
the third passage of sgHCC was probably caused by
mutation of one or several key genes. fgHCC differed
from the parental strain by signiﬁcantly higher growth
rate (intervals between passages were 5–7 months and
two weeks for sgHCC and fgHCC, respectively).
fgHCC was characterized by low ploity, complete loss
of cell polarity, a striking decrease in cell–cell contacts
and with extracellular matrix adhesion. The fgHCC
cells synthesized much less if any SA, transferrin, and
other differentiation marker proteins [14, 15].
The Tissue-Specific Gene Expression
during Progression of Mouse Hepatocellular Carcinoma
E. V. Varga, O. A. Cheremnova, D. A. Ovchinnikov, A. Yu. Shapiguzov, E. I. Kudryavtseva,
O. V. Morozova, N. V. Engelhardt, and N. L. Lazarevich
Institute of Carcinogenesis, Blokhin Cancer Research Center, Russian Academy of Medical Science,
Moscow, 115478 Russia; fax: (095) 324-12-05; e-mail: email@example.com
Received November 9, 2000
—Expression of hepato-speciﬁc genes in slow- and fast-growing hepatocellular murine carcinomas
was studied. A fast-growing dedifferentiated transplantable hepatocarcinoma variant (fgHCC) arose from the
highly differentiated slow-growing hepatocarcinoma (sgHCC). In contrast to the parental hepatocarcinoma,
expression of the hepatocyte nuclear factor 4 (HNF4), one of the key regulators of hepatocyte differentiation,
and several HNF-4-responsive genes, transferrin, transthyretin, hepatocyte nuclear factor 1 (HNF1), and serum
albumin, was downregulated in fgHCC. The expression of exogenous HNF4 in the fgHCC cell culture partially
restored the expression of hepato-speciﬁc genes and led to the formation of epithelial islets in the culture. The
described system may serve as an appropriate model for further analysis of mechanisms underlying hepatocar-
cinogenesis and liver tumor progression.