Suppression of Anchorage-Independent Growth of Human Cancer Cell
Lines by the TRIF52/Periostin/OSF-2 Gene
Naohisa Yoshioka,* Shigeo Fuji,* Misuzu Shimakage,† Ken Kodama,‡ Akira Hakura, Masuo Yutsudo,§
Hirokazu Inoue,
¶
and Hiroshi Nojima*
,1
*Department of Molecular Genetics, §Department of Bacterial Infections, and Department of Tumor Virology, Research Institute for
Microbial Diseases, Osaka University, Suita 565-0871, Japan; †Clinical Research Institute, Osaka National Hospital,
Osaka 540-0006, Japan; ‡Department of Thoracic Surgery, Osaka Medical Center for Cancer and Cardiovascular Diseases,
Osaka 537-8511, Japan; and
¶
Department of Microbiology, Shiga University of Medical Science, Otsu 520-2192, Japan
In searching for genes that suppress the viral trans-
formation of primary cells, we have isolated a number
of TRIF (transcript reduced in F2408) genes that are
expressed well in primary rat embryo fibroblasts
(REFs) but poorly in spontaneously immortalized rat
fibroblast cell lines derived from REFs. One of these
genes, TRIF52, is a rat homologue of the mouse protein
periostin, which is suspected of being involved in on-
cogenesis. We found here that periostin mRNA expres-
sion is markedly downregulated in a variety of human
cancer cell lines and human lung cancer tissues. Hu-
man cancer cell lines with reduced endogenous peri-
ostin gene expression that were infected with a recom-
binant retrovirus containing the periostin gene had
reduced anchorage-independent growth. Mutational
analysis revealed that the C-terminal region of perios-
tin is sufficient to convey the anchorage-independent
growth-suppressive activity of the protein. These ob-
servations together suggest that periostin may serve
to inhibit the development of human cancers by acting
as a tumor suppressor.
© 2002 Elsevier Science (USA)
Key Words: periostin; tumor suppression; anchorage-
independent growth; primary cells; transformation.
INTRODUCTION
We have reported previously that factors that sup-
press transformation by viral oncogenes are expressed
in primary rat embryo fibroblasts (REFs) [1]. To iden-
tify such transformation suppressor genes, we used
cDNA subtraction to isolate 30 different cDNA clones
whose mRNA expression is markedly reduced in the
rat fibroblast cell line F2408 [1]. We referred to these
clones as TRIF (transcript reduced in F2408). In a
previous article, we demonstrated that TRIF3 (lumi-
can) suppresses transformation by v-src and v-K-ras
oncogenes, which suggests that the other TRIF genes
may also be transformation suppressor candidates [1].
In this article, we focus on TRIF52, a rat homologue
of mouse periostin. Periostin, formerly called osteo-
blast-specific factor 2 (osf-2), was previously isolated as
an osteoblast-specific gene from a cDNA library of the
mouse osteoblastic cell line MC3T3-E1 by subtraction
hybridization and differential screening techniques [2].
Periostin has a typical signal peptide sequence at its N
terminus and four repeated domains. Each of the latter
domains contain two highly conserved sequences that
have been found in the fasciclin I family of proteins [2,
3]. Periostin is particularly highly homologous to

ig-
h3, one of the fasciclin I protein family, which has been
isolated as a transforming growth factor

(TGF-

)-
responsive gene [4].

ig-h3 promotes the cell adhesion
and spreading of fibroblasts via integrin
␣
1

2 [5, 6] but
also suppresses the ability of CHO cells to develop into
tumors in nude mice [7]. Periostin is also involved in
the cell adhesion and spreading of osteoblastic cells [3].
In addition, the protein expression of periostin is in-
creased by TGF-

[3], and mRNA expression of perios-
tin is downregulated by the introduction of Wnt-3 and
by the inhibition of glycogen synthase kinase 3

(GSK-
3

) [8]. These observations suggest that loss of perios-
tin expression could promote oncogenesis.
To clarify whether periostin/TRIF52 could inhibit
human oncogenesis as a tumor suppressor, we investi-
gated the expression of periostin mRNA in a variety of
human cancer cell lines and several human lung can-
cer tissues. We found most tumors poorly expressed
periostin mRNA. Furthermore, we tested the ability of
exogenous periostin to suppress the malignant pheno-
type of those human cancer cell lines with a downregu-
lated expression of periostin mRNA. We found that
periostin can suppress the anchorage-independent
growth of these cells, supporting the notion that peri-
ostin has a tumor suppressor function in human onco-
genesis.
1
To whom reprint requests should be addressed. Fax: ϩ81 6 6875
5192. E-mail: hnojima@biken.osaka-u.ac.jp
0014-4827/02 $35.00
91
© 2002 Elsevier Science (USA)
All rights reserved.
Experimental Cell Research 279, 91–99 (2002)
doi:10.1006/excr.2002.5590