ABSTRACT
Epithelial ovarian cancer (EOC) is the most lethal gynecologic malignancy, and its vulnerability to metastasis contributes to the poor outcomes of EOC patients. Long noncoding RNAs (lncRNAs) were verified to play a pivotal role in EOC metastasis. However, the potential role of lncRNA membrane-associated guanylate kinase inverted 1 (MAGI1) intronic transcript (MAGI1-IT1) in EOC is largely unknown. In this study, the function and mechanisms of MAGI1-IT1 in EOC metastasis were explored profoundly. First, MAGI1-IT1 expression was found to be significantly decreased in overexpressing miR-200a EOC cells. Second, MAGI1-IT1 expression was remarkably increased in metastatic EOC tissues, and high MAGI1-IT1 was dramatically associated with EOC FIGO III-IV stage; in addition, MAGI1-IT1 might be related to EOC dissemination via epithelial-mesenchymal transition (EMT). Next, a series of gain- and loss-of-function assays verified that, although MAGI1-IT1 has no significant role in EOC proliferation and subcutaneous xenograft growth, the upregulation of MAGI1-IT1 can remarkably facilitate EOC EMT phenotype, cells migration and invasion ability and intraperitoneal metastasis in nude mice, while downregulation of MAGI1-IT1 led to the opposite effect in vitro. Moreover, MAGI1-IT1 was validated to promote EOC metastasis through upregulation of ZEB1 and ZEB2 by competitively binding miR-200a, and the restrictive effects of MAGI1-IT1 depletion on EOC metastasis could be reversed by inhibition of miR-200a and upregulation of ZEB1 and ZEB2. Collectively, these results suggest that MAGI1-IT1 may work as a ceRNA in promoting EOC metastasis through miR-200a and ZEB1/2 and may be a potential therapeutic target for EOC.
Subject(s)
Carcinoma, Ovarian Epithelial/genetics , Carcinoma, Ovarian Epithelial/pathology , MicroRNAs/metabolism , RNA, Long Noncoding/metabolism , Signal Transduction , Zinc Finger E-box-Binding Homeobox 1/metabolism , Animals , Base Sequence , Carcinoma, Ovarian Epithelial/ultrastructure , Cell Line, Tumor , Cell Movement/genetics , Cell Proliferation/genetics , Female , Gene Expression Regulation, Neoplastic , Gene Regulatory Networks , Humans , Mice, Nude , MicroRNAs/genetics , Middle Aged , Neoplasm Invasiveness , Neoplasm Metastasis , RNA, Long Noncoding/genetics , Signal Transduction/genetics , Zinc Finger E-box-Binding Homeobox 1/geneticsABSTRACT
There is growing appreciation of the importance of the mechanical properties of the tumor microenvironment on disease progression. However, the role of extracellular matrix (ECM) stiffness and cellular mechanotransduction in epithelial ovarian cancer (EOC) is largely unknown. Here, we investigated the effect of substrate rigidity on various aspects of SKOV3 human EOC cell morphology and migration. Young's modulus values of normal mouse peritoneum, a principal target tissue for EOC metastasis, were determined by atomic force microscopy (AFM) and hydrogels were fabricated to mimic these values. We find that cell spreading, focal adhesion formation, myosin light chain phosphorylation, and cellular traction forces all increase on stiffer matrices. Substrate rigidity also positively regulates random cell migration and, importantly, directional increases in matrix tension promote SKOV3 cell durotaxis. Matrix rigidity also promotes nuclear translocation of YAP1, an oncogenic transcription factor associated with aggressive metastatic EOC. Furthermore, disaggregation of multicellular EOC spheroids, a behavior associated with dissemination and metastasis, is enhanced by matrix stiffness through a mechanotransduction pathway involving ROCK, actomyosin contractility, and FAK. Finally, this pattern of mechanosensitivity is maintained in highly metastatic SKOV3ip.1 cells. These results establish that the mechanical properties of the tumor microenvironment may play a role in EOC metastasis.
