LPA receptor 2 mediates LPA-induced endometrial cancer invasion.
OBJECTIVE
We have previously shown that lysophosphatidic acid (LPA) promotes the ovarian cancer metastatic cascade. In this study, we evaluated the role of LPA on endometrial cancer invasion.


METHODS
Transient mRNA knockdown was accomplished using pre-designed siRNA duplexes against LPA receptor 2 (LPA2) and human matrix metalloproteinase-7 (MMP-7). RT-PCR was used to characterize LPA receptor and MMP-7 expression. Analysis of in vitro invasion was performed with rat-tail collagen type I coated Boyden chambers. Gelatin zymography was used to evaluate the MMP activity in cell culture conditioned media. Cell-cell and cell-matrix attachment was also assessed upon LPA2 knockdown to further illuminate the LPA2 cascade.


RESULTS
LPA increases HEC1A cellular invasion at physiologic concentrations (0.1-1 muM). Of the four principle LPA receptors, LPA2 is predominantly expressed by HEC1A cells. Transient transfection of LPA2 siRNA reduced LPA2 mRNA expression in HEC1A cells by 93% (P<0.01). Silencing LPA2 eliminated the LPA-stimulated increase in invasion (P<0.05) and reduced LPA-induced MMP-7 secretion/activation, without significantly affecting cell-cell or cell-matrix adhesion. Silencing MMP-7 reduced overall invasion but did not eliminate LPA's pro-invasive effect on HEC1A cells, as compared to negative control (P<0.05). Gelatin zymography confirmed that LPA2 and MMP-7 knockdown reduced MMP-7 activation in HEC1A conditioned media.


CONCLUSIONS
LPA2 mediates LPA-stimulated HEC1A invasion and the subsequent activation of MMP-7.
Hope
Joanie Mayer
JM
Department of Obstetrics and Gynecology, New York University School of Medicine, New York, NY 10016, USA. joanie.hope@nyumc.org
Wang
Feng-Qiang
FQ
Whyte
Jill S
JS
Ariztia
Edgardo V
EV
Abdalla
Walid
W
Long
Kara
K
Fishman
David A
DA
D002448:Cell Adhesion / Q000187:drug effects / Q000502:physiology; D002450:Cell Communication / Q000187:drug effects / Q000502:physiology; D045744:Cell Line, Tumor; D016889:Endometrial Neoplasms / Q000235:genetics / Q000378:metabolism* / Q000473:pathology*; D004789:Enzyme Activation; D005109:Extracellular Matrix / Q000473:pathology; D005260:Female; D020868:Gene Silencing; D006801:Humans; D008246:Lysophospholipids / Q000494:pharmacology*; D020778:Matrix Metalloproteinase 2 / Q000378:metabolism; D020783:Matrix Metalloproteinase 7 / Q000378:metabolism; D009361:Neoplasm Invasiveness; D034741:RNA, Small Interfering / Q000235:genetics; D049368:Receptors, Lysophosphatidic Acid / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D014162:Transfection
D008246:Lysophospholipids; D034741:RNA, Small Interfering; D049368:Receptors, Lysophosphatidic Acid; C060932:MMP7 protein, human; D020783:Matrix Metalloproteinase 7; D020778:Matrix Metalloproteinase 2; C032881:lysophosphatidic acid