The granulin-epithelin precursor/PC-cell-derived growth factor is a growth factor for epithelial ovarian cancer.
OBJECTIVE
The role of growth factors in ovarian cancer development and progression is complex and multifactorial. We hypothesized that new growth factors may be identified through the molecular analysis of ovarian tumors as they exist in their native environment.


METHODS
RNA extracted from microdissected serous low malignant potential (LMP) and invasive ovarian tumors was used to construct cDNA libraries. A total of 7300 transcripts were randomly chosen for sequencing, and those transcripts were statistically evaluated. Reverse transcription-PCR and immunohistochemistry were used to validate the findings in tumor tissue samples. Ovarian cancer cell lines were used to test gene effects on monolayer growth, proliferative capacity, and density-independent growth.


RESULTS
Analysis of the pooled library transcripts revealed 26 genes differentially expressed between LMP and invasive ovarian cancers. The granulin-epithelin precursor [GEP/PC-cell derived growth factor (PCDGF)] was expressed only in the invasive ovarian cancer libraries (P < 0.028) and was absent in the LMP libraries (0 of 2872 clones). All of the invasive tumor epithelia, 20% of the LMP tumor epithelia, and all of the stroma from both subsets expressed GEP by reverse transcription-PCR. Immunohistochemical staining for GEP was diffuse and cytosolic in invasive ovarian cancer tumor cells compared with occasional, punctate, and apical staining in LMP tumor epithelia. Antisense transfection of GEP into ovarian cancer cell lines resulted in down-regulation of GEP production, reduction in cell growth (P < 0.002), decrease in the S-phase fraction (P < 0.04), and loss of density-independent growth potential (P < 0.01).


CONCLUSIONS
cDNA library preparation from microdissected tumor epithelium provided a selective advantage for the identification of growth factors for epithelial ovarian cancer. Differential granulin expression in tumor samples and the antiproliferative effects of its antisense down-regulation suggest that GEP may be a new autocrine growth factor and molecular target for epithelial ovarian cancer.
Jones
Monica Brown
MB
Laboratory of Pathology, National Cancer Institute, Bethesda, Maryland 20892-1500, USA.
Michener
Chad M
CM
Blanchette
James O
JO
Kuznetsov
Vladimir A
VA
Raffeld
Mark
M
Serrero
Ginette
G
Emmert-Buck
Michael R
MR
Petricoin
Emanuel F
EF
Krizman
David B
DB
Liotta
Lance A
LA
Kohn
Elise C
EC
D002455:Cell Division; D003001:Cloning, Molecular; D018076:DNA, Complementary / Q000378:metabolism; D019992:Databases as Topic; D004848:Epithelium / Q000473:pathology*; D005260:Female; D015723:Gene Library; D006023:Glycoproteins / Q000096:biosynthesis* / Q000235:genetics; D006133:Growth Substances / Q000096:biosynthesis* / Q000235:genetics / Q000378:metabolism; D006801:Humans; D007150:Immunohistochemistry; D036341:Intercellular Signaling Peptides and Proteins; D005810:Multigene Family; D016376:Oligonucleotides, Antisense / Q000378:metabolism; D010051:Ovarian Neoplasms / Q000378:metabolism*; D000077153:Progranulins; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013997:Time Factors; D014018:Tissue Distribution; D014162:Transfection; D014407:Tumor Cells, Cultured
D018076:DNA, Complementary; D006023:Glycoproteins; D006133:Growth Substances; D036341:Intercellular Signaling Peptides and Proteins; D016376:Oligonucleotides, Antisense; D000077153:Progranulins