Tumor suppressor effect of follistatin-like 1 in ovarian and endometrial carcinogenesis: a differential expression and functional analysis.
Endometrial and ovarian cancers are the most common and the most lethal gynecologic malignancies worldwide, respectively. By performing differential expression analysis using annealing control primer-based reverse transcription (RT)-polymerase chain reaction (PCR) on pooled complementary DNA (cDNA) from 45 endometrial and 36 ovarian cancers and their non-tumor samples, reduced expression of the follistatin-like 1 (FSTL1) was identified. Downregulation of FSTL1 was further confirmed on individual samples and cell lines by quantitative real-time RT-PCR and western blotting. For in vitro functional study, full-length cDNA of FSTL1 was cloned and transiently transfected into the ovarian cancer cell line Ovca420 and endometrial cancer cell line AN3CA. 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide assay and cell count demonstrated significantly slower proliferation rate. By terminal uridine deoxynucleotidyl transferase dUTP nick end labeling and flow cytometric analysis, higher apoptotic activity and a remarkable increase in sub-G(1) cell population were observed in transfected cells, suggesting that FSTL1 induced apoptosis in cancer cells. Subsequent messenger RNA and protein expression analysis on downstream apoptotic molecules revealed upregulation and/or activation of FAS, FASLG, TRADD, Caspase-3, Caspase-7 and PARP by FSTL1 transfection, suggesting that FSTL1-induced apoptosis may be initiated mainly by FAS/FASLG death receptor-ligand binding. Cell migration and invasion assays demonstrated a remarkably lower cell migration and invasion capability in FSTL1-transfected cells in relation to downregulation of matrix metallopeptidase-2. Our findings suggested that a tumor suppressor role of FSTL1 may be important in ovarian and endometrial carcinogenesis.
Chan
Queeny K Y
QK
Department of Pathology, The University of Hong Kong, Queen Mary Hospital, Hong Kong, China.
Ngan
Hextan Y S
HY
Ip
Philip P C
PP
Liu
Vincent W S
VW
Xue
W C
WC
Cheung
Annie N Y
AN
D017209:Apoptosis; D015153:Blotting, Western; D049109:Cell Proliferation; D015536:Down-Regulation; D016889:Endometrial Neoplasms / Q000473:pathology / Q000503:physiopathology*; D005260:Female; D005434:Flow Cytometry; D038702:Follistatin-Related Proteins / Q000235:genetics / Q000502:physiology*; D016147:Genes, Tumor Suppressor; D006801:Humans; D020287:In Situ Nick-End Labeling; D009361:Neoplasm Invasiveness; D009362:Neoplasm Metastasis; D010051:Ovarian Neoplasms / Q000473:pathology / Q000503:physiopathology*; D020133:Reverse Transcriptase Polymerase Chain Reaction
D038702:Follistatin-Related Proteins; C448799:FSTL1 protein, human