Differential effects of tumor necrosis factor-α on matrix metalloproteinase-2 expression in human myometrial and uterine leiomyoma smooth muscle cells.
OBJECTIVE
Does tumor necrosis factor-α (TNF-α) differentially regulate matrix metalloproteinase-2 (MMP-2) expression in leiomyomas compared with normal myometrium?


CONCLUSIONS
TNF-α up-regulates MMP-2 expression and stimulates cell migration through the activation of extracellular signal-regulated kinase (ERK) signaling pathway in leiomyoma smooth muscle cells (SMCs), but not in normal myometrial SMCs.


BACKGROUND
Uterine leiomyoma, the benign smooth muscle cell tumor, is the single most common indication for hysterectomy. High expression of MMPs or TNF-α has been reported in uterine leiomyomas; however, the molecular mechanism underlying these observations remains unknown.


METHODS
Samples were obtained between 2009 and 2013 from 12 women of reproductive age at the proliferative phase of the menstrual cycle by hysterectomy. Leiomyomas and matched normal myometrium from each woman were analyzed in vitro.


METHODS
Western blot, RT-qPCR and a wound-healing assay were used to investigate the effects of TNF-α on MMP-2 expression and intracellular signal transduction in cultured SMCs from leiomyomas and matched myometrium.


RESULTS
Western blot and RT-qPCR analyses using tissues from clinical patients showed that the levels of MMP-2 protein (P = 0.008) and mRNA (P = 0.009) were significantly higher in uterine leiomyomas compared with their matched myometrium. Treatment with TNF-α significantly up-regulated the protein (P = 0.039) and mRNA (P = 0.037) levels of MMP-2 in cultured leiomyoma SMCs but not in matched myometrial SMCs. The extracellular signal-regulated kinase (ERK) and nuclear factor-kappa B (NF-κB) pathways were activated by TNF-α in leiomyoma SMCs. Specific inhibitors of the ERK or NF-κB pathway (PD98059 or Bay11-7082) suppressed TNF-α-induced MMP-2 expression in leiomyoma SMCs. The wound-healing assay revealed that TNF-α promoted the migration of cultured leiomyoma SMCs (P = 0.036); however, PD98059 compromised the cell migration triggered by TNF-α.


CONCLUSIONS
This study is descriptive and although we observed clear differential regulation of MMP-2 by TNF-α at mRNA and protein levels in leiomyoma, future studies are needed to identify why the difference in TNF-α response exists between human leiomyoma tissue and normal myometrium. Including some of the experiments such as transfection studies for TNF-α and MMP-2 promoter mapping could have added more insight as to why this difference exists. In addition, further studies in vivo are needed to verify the results obtained from primary cultured SMCs.


CONCLUSIONS
Considering the positive effect of TNF-α on leiomyoma SMC migration, strategies targeting TNF-α, in parallel with the production of more speciﬁc inhibitors of MMPs, may provide alternative therapeutic approaches for the treatment of leiomyoma.


BACKGROUND
This work was partially supported by grants from the Program for New Century Excellent Talents in University (NCET-12-0282), National Natural Science Foundation of China (81371620) and Tianjin Natural Science Foundation (12JCZDJC24900). The authors have no conflicts of interest to declare.
Department of Pathophysiology, Nankai University School of Medicine, Tianjin, China.
Yuebing
Y
Wang
Department of Pathophysiology, Nankai University School of Medicine, Tianjin, China Department of Urology, Second Hospital of Tianjin Medical University, Tianjin, China.
Guowei
G
Feng
Graduate School, Tianjin Medical University, Tianjin, China.
Jiyuan
J
Wang
Graduate School, Tianjin Medical University, Tianjin, China.
Yu
Y
Zhou
Department of Gynecology, Tianjin Central Hospital for Obstetrics and Gynecology, Tianjin, China.
Yixin
Y
Liu
Department of Gynecology, Tianjin Central Hospital for Obstetrics and Gynecology, Tianjin, China.
Yiquan
Y
Shi
Department of Gynecology, Tianjin Central Hospital for Obstetrics and Gynecology, Tianjin, China.
Yingjun
Y
Zhu
Department of Gynecology, Tianjin Central Hospital for Obstetrics and Gynecology, Tianjin, China.
Wanjun
W
Lin
Department of Pathophysiology, Nankai University School of Medicine, Tianjin, China.
Yang
Y
Xu
Department of Pathophysiology, Nankai University School of Medicine, Tianjin, China zongjinli@nankai.edu.cn.
Zongjin
Z
Li
D000328:Adult; D002465:Cell Movement; D002478:Cells, Cultured; D005260:Female; D005498:Follicular Phase / Q000378:metabolism; D006801:Humans; D007889:Leiomyoma / Q000378:metabolism*; D020935:MAP Kinase Signaling System; D020778:Matrix Metalloproteinase 2 / Q000378:metabolism*; D008875:Middle Aged; D032389:Myocytes, Smooth Muscle / Q000378:metabolism; D009215:Myometrium / Q000378:metabolism*; D016328:NF-kappa B / Q000378:metabolism; D015398:Signal Transduction; D014409:Tumor Necrosis Factor-alpha / Q000235:genetics / Q000378:metabolism / Q000502:physiology*
D016328:NF-kappa B; D014409:Tumor Necrosis Factor-alpha; D020778:Matrix Metalloproteinase 2
extracellular signal-regulated kinase (ERK); matrix metalloproteinase (MMP); tumor necrosis factor-α (TNF-α); uterine leiomyoma