The increased expression of periostin during early stages of prostate cancer and advanced stages of cancer stroma.
BACKGROUND
Three-dimensional culture (3DC) is a relevant in vitro model used to study prostate development and carcinogenesis. Recent studies have indicated that 3DC-associated genes would be more sensitive as prognostic markers for cancer; however, no 3DC-associated genes in prostate cancer (CaP) have thus far been elucidated.


METHODS
Candidate 3DC-associated genes in non-malignant prostatic epithelial cells, RWPE-1 and TA2, were selected, based on a comparison of microarray gene expression data between cells grown in two-dimensional culture (2DC) and in 3DC. To extract CaP-associated genes among the 3DC-associated genes, gene expression levels from the microdissected tissue samples were compared between 20 well-differentiated or 20 poorly differentiated CaP, as well as matched normal prostate epithelium. The expression levels of CaP-associated genes in 3DC were validated by quantitative RT-PCR using TA2 cells in 2DC and 3DC. Protein expression of periostin (POSTN), which is one of the 3DC CaP-associated genes, was further evaluated in the clinical samples by immunohistochemistry.


RESULTS
Several genes including POSTN were identified as CaP-associated genes using a 3DC system. Immunohistochemical analyses revealed that POSTN expression was increased in the early stages of CaP (Gleason score 6-7), but not in the advanced stages of CaP. Furthermore, the positive ratio observed for the expression of POSTN in tumor-associated stroma was significantly correlated with the degree of malignancy.


CONCLUSIONS
POSTN, one of the 3DC-associated genes, may serve as a potential biomarker for predicting the pathological grade and prognosis of CaP. Prostate 69: 1398-1403, 2009. (c) 2009 Wiley-Liss, Inc.
Tsunoda
Toshiyuki
T
Faculty of Medicine, Department of Cell Biology, Fukuoka University, Nanakuma, Jonan-ku, Fukuoka, Japan. tsunoda@fukuoka-u.ac.jp
Furusato
Bungo
B
Takashima
Yasuo
Y
Ravulapalli
Suma
S
Dobi
Albert
A
Srivastava
Shiv
S
McLeod
David G
DG
Sesterhenn
Isabell A
IA
Ornstein
David K
DK
Shirasawa
Senji
S
D014408:Biomarkers, Tumor / Q000235:genetics*; D015815:Cell Adhesion Molecules / Q000235:genetics*; D018929:Cell Culture Techniques / Q000379:methods*; D018450:Disease Progression; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D020411:Oligonucleotide Array Sequence Analysis; D011379:Prognosis; D011471:Prostatic Neoplasms / Q000235:genetics / Q000473:pathology*; D012720:Severity of Illness Index; D017154:Stromal Cells / Q000473:pathology / Q000502:physiology*; D014407:Tumor Cells, Cultured
D014408:Biomarkers, Tumor; D015815:Cell Adhesion Molecules; C512835:POSTN protein, human