title: Protease-activated-receptor-2 affects protease-activated-receptor-1-driven breast cancer.
abstract: Mammalian protease-activated-receptor-1 and -2 (PAR1 and PAR2) are activated by proteases found in the flexible microenvironment of a tumor and play a central role in breast cancer. We propose in the present study that PAR1 and PAR2 act together as a functional unit during malignant and physiological invasion processes. This notion is supported by assessing pro-tumor functions in the presence of short hairpin; shRNA knocked-down hPar2 or by the use of a truncated PAR2 devoid of the entire cytoplasmic tail. Silencing of hPar2 by shRNA-attenuated thrombin induced PAR1 signaling as recapitulated by inhibiting the assembly of Etk/Bmx or Akt onto PAR1-C-tail, by thrombin-instigated colony formation and invasion. Strikingly, shRNA-hPar2 also inhibited the TFLLRN selective PAR1 pro-tumor functions. In addition, while evaluating the physiological invasion process of placenta extravillous trophoblast (EVT) organ culture, we observed inhibition of both thrombin or the selective PAR1 ligand; TFLLRNPNDK induced EVT invasion by shRNA-hPar2 but not by scrambled shRNA-hPar2. In parallel, when a truncated PAR2 was utilized in a xenograft mouse model, it inhibited PAR1-PAR2-driven tumor growth in vivo. Similarly, it also attenuated the interaction of Etk/Bmx with the PAR1-C-tail in vitro and decreased markedly selective PAR1-induced Matrigel invasion. Confocal images demonstrated co-localization of PAR1 and PAR2 in HEK293T cells over-expressing YFP-hPar2 and HA-hPar1. Co-immuno-precipitation analyses revealed PAR1-PAR2 complex formation but no PAR1-CXCR4 complex was formed. Taken together, our observations show that PAR1 and PAR2 act as a functional unit in tumor development and placenta-uterus interactions. This conclusion may have significant consequences on future breast cancer therapeutic modalities and improved late pregnancy outcome.
authors.affiliation: Sharett-Institute of Oncology, Hadassah-Hebrew University Medical Center, POB 12000, 91120, Jerusalem, Israel.
authors.forename: Mohammad
authors.initials: M
authors.lastname: Jaber
authors.forename: Miriam
authors.initials: M
authors.lastname: Maoz
authors.forename: Arun
authors.initials: A
authors.lastname: Kancharla
authors.forename: Daniel
authors.initials: D
authors.lastname: Agranovich
authors.forename: Tamar
authors.initials: T
authors.lastname: Peretz
authors.forename: Sorina
authors.initials: S
authors.lastname: Grisaru-Granovsky
authors.forename: Beatrice
authors.initials: B
authors.lastname: Uziely
authors.forename: Rachel
authors.initials: R
authors.lastname: Bar-Shavit
mesh_terms: D000818:Animals; D001943:Breast Neoplasms / Q000235:genetics* / Q000473:pathology / Q000628:therapy; D005260:Female; D015972:Gene Expression Regulation, Neoplastic; D057809:HEK293 Cells; D006801:Humans; D051379:Mice; D009842:Oligopeptides / Q000378:metabolism; D011247:Pregnancy; D034741:RNA, Small Interfering / Q000235:genetics / Q000378:metabolism; D044463:Receptor, PAR-1 / Q000235:genetics* / Q000378:metabolism; D044464:Receptor, PAR-2 / Q000235:genetics* / Q000378:metabolism; D019718:Receptors, CXCR4 / Q000235:genetics; D059016:Tumor Microenvironment / Q000235:genetics*; D023041:Xenograft Model Antitumor Assays
chemical_list: C527276:CXCR4 protein, human; D009842:Oligopeptides; D034741:RNA, Small Interfering; D044463:Receptor, PAR-1; D044464:Receptor, PAR-2; D019718:Receptors, CXCR4; C508781:threonyl-phenylalanyl-leucyl-leucyl-arginyl-asparagine