The involvement of osteopontin and matrix metalloproteinase- 9 in the migration of endometrial epithelial cells in patients with endometriosis.
BACKGROUND
Endometriosis, which shares certain characteristics with cancers, may cause abnormal expression of proteins involved in cell migration. Endometrial epithelial cells (EECs) are believed to play an important role in endometriotic migration. The aim of this study was to investigate the relationship between the expression of osteopontin (OPN) and matrix metalloproteinase-9 (MMP-9) in endometriotic migration.


METHODS
We performed primary culture of EECs and investigated the expression of OPN and MMP-9 in EECs regulated by 17beta-estradiol (E2). OPN-specific siRNA interference was used to down-regulate OPN and to explore the corresponding change in MMP-9 expression. Real-time RT-PCR, western blot analysis and flow cytometry were used to determine the expression levels of OPN and MMP-9. Gelatin zymography was performed to observe the enzymatic activity of MMP-9 in conditioned media. Transwell and wound scratch assays were performed to investigate the migration ability of EECs.


RESULTS
The expression levels of OPN and MMP-9 in normal EECs (NEECs) were inferior to those in EECs from patients with endometriosis (EEECs). The expression levels of OPN and MMP-9 from stage III/IV EEECs and secretory-phase EECs were higher than those of stage I/II EEECs or proliferative-phase EECs. The expression levels of OPN and MMP-9 in EEECs were increased by E2 treatment and remarkably decreased by siRNA interference. Active MMP-9 expression increased with E2 treatment and decreased with siRNA treatment in EEECs compared with the same treatments in NEECs. The migratory abilities of EEECs were enhanced after cells were treated with E2; in contrast, these abilities were reduced by siRNA interference. In NEECs, active MMP-9 and cellular migration abilities were only minimally influenced by E2 and siRNA treatment.


CONCLUSIONS
The present study suggests that the up-regulation of MMP-9 via activation of OPN induced by estrogen may correlate with the migration of endometrial epithelial cells in patients with endometriosis.
Ningxia Medical University, Yinchuan, Ningxia, China. yangmei_hz@163.com.|Department of Obstetrics and Gynecology, Xiangyang Central Hospital, Affiliated Hospital of Hubei University of Arts and Science, Xiangyang, Hubei, China. yangmei_hz@163.com.
Mei
M
Yang
Department of Pathology, Xiangyang Central Hospital, Affiliated Hospital of Hubei University of Arts and Science, Xiangyang, Hubei, China. tissuefox@gmail.com.
Chunfan
C
Jiang
Department of Obstetrics and Gynecology in General Hospital, Key Laboratory of Fertility Preservation and Maintenance of the Ministry of Education, Ningxia Medical University, Yinchuan, Ningxia, China. chenghua6879@163.com.
Hua
H
Chen
Ningxia Medical University, Yinchuan, Ningxia, China. ny201209@163.com.
Yan
Y
Nian
Ningxia Medical University, Yinchuan, Ningxia, China. 1056259018@qq.com.
Zhimiao
Z
Bai
Department of Obstetrics and Gynecology in General Hospital, Key Laboratory of Fertility Preservation and Maintenance of the Ministry of Education, Ningxia Medical University, Yinchuan, Ningxia, China. hachunfang@gmail.com.
Chunfang
C
Ha
D000328:Adult; D002465:Cell Movement / Q000187:drug effects / Q000502:physiology*; D002478:Cells, Cultured; D004715:Endometriosis / Q000378:metabolism* / Q000473:pathology; D004717:Endometrium / Q000187:drug effects / Q000378:metabolism* / Q000473:pathology; D004847:Epithelial Cells / Q000187:drug effects / Q000378:metabolism* / Q000473:pathology; D004967:Estrogens / Q000494:pharmacology; D005260:Female; D006801:Humans; D020780:Matrix Metalloproteinase 9 / Q000096:biosynthesis*; D053495:Osteopontin / Q000096:biosynthesis*; D055815:Young Adult
D004967:Estrogens; D053495:Osteopontin; C579270:MMP9 protein, human; D020780:Matrix Metalloproteinase 9