title: Inhibition of rho-associated kinase signaling prevents breast cancer metastasis to human bone.
abstract: Rho-associated kinase (ROCK) signaling plays a fundamental role in regulating cell morphology, adhesion, and motility. Aberrant expression of ROCK is related to tumor metastases and poor clinical outcome. Here, we show that ROCK expression is increased in metastatic human mammary tumors and breast cancer cell lines compared with nonmetastatic tumors and cell lines. Overexpression of ROCK confers a metastatic phenotype on the nonmetastatic MCF-7 cell line. Inhibition of ROCK activity, by either a specific ROCK inhibitor (Y27632) or ROCK-targeted small interfering RNAs, reduces cell migration and proliferation in vitro and metastasis to bone in vivo using a novel "human breast cancer metastasis to human bone" mouse model. Expression of the c-Myc-regulated miR-17-92 cluster is shown to be elevated in metastatic breast cancer cells compared with nonmetastatic cells and diminished by Y27632 treatment. Furthermore, blockade of miR-17 is shown to decrease breast cancer cell invasion/migration in vitro and metastasis in vivo. Together, these findings suggest that augmented ROCK signaling contributes to breast cancer metastasis. The effects of ROCK on tumor cell invasion/motility and growth may derive from regulating cytoskeletal actin-myosin contraction and modulating the c-Myc pathway, including c-Myc-dependent microRNAs. Inhibition of ROCK or the pathway it stimulates, therefore, may represent a novel approach for treatment of breast cancer metastases.
authors.affiliation: Department of Physiology, Tufts University School of Medicine, Boston, Massachusetts 02111-1800, USA.
authors.forename: Sijin
authors.initials: S
authors.lastname: Liu
authors.forename: Robert H
authors.initials: RH
authors.lastname: Goldstein
authors.forename: Ellen M
authors.initials: EM
authors.lastname: Scepansky
authors.forename: Michael
authors.initials: M
authors.lastname: Rosenblatt
mesh_terms: D000818:Animals; D015153:Blotting, Western; D001859:Bone Neoplasms / Q000201:enzymology / Q000235:genetics / Q000556:secondary*; D001943:Breast Neoplasms / Q000201:enzymology* / Q000235:genetics / Q000473:pathology; D002465:Cell Movement / Q000187:drug effects / Q000502:physiology; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005260:Female; D005434:Flow Cytometry; D015870:Gene Expression / Q000187:drug effects; D020869:Gene Expression Profiling; D006801:Humans; D051379:Mice; D035683:MicroRNAs / Q000187:drug effects / Q000235:genetics / Q000378:metabolism; D009361:Neoplasm Invasiveness / Q000235:genetics* / Q000473:pathology; D009362:Neoplasm Metastasis / Q000235:genetics / Q000473:pathology; D020411:Oligonucleotide Array Sequence Analysis; D016271:Proto-Oncogene Proteins c-myc / Q000187:drug effects / Q000235:genetics / Q000378:metabolism; D012333:RNA, Messenger; D034741:RNA, Small Interfering; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015398:Signal Transduction / Q000502:physiology*; D054460:rho-Associated Kinases / Q000378:metabolism*
chemical_list: D004791:Enzyme Inhibitors; D035683:MicroRNAs; C543614:Mirn17 microRNA, mouse; C541873:Mirn92 microRNA, mouse; D016271:Proto-Oncogene Proteins c-myc; D012333:RNA, Messenger; D034741:RNA, Small Interfering; D054460:rho-Associated Kinases