title: ROCK1 & 2 perform overlapping and unique roles in angiogenesis and angiosarcoma tumor progression.
abstract: The serine/threonine protein kinase paralogs ROCK1 & 2 have been implicated as essential modulators of angiogenesis; however their paralog-specific roles in endothelial function are unknown. shRNA knockdown of ROCK1 or 2 in endothelial cells resulted in a significant disruption of in vitro capillary network formation, cell polarization, and cell migration compared to cells harboring non-targeting control shRNA plasmids. Knockdowns led to alterations in cytoskeletal dynamics due to ROCK1 & 2-mediated reductions in actin isoform expression, and ROCK2-specific reduction in myosin phosphatase and cofilin phosphorylation. Knockdowns enhanced cell survival and led to ROCK1 & 2-mediated reduction in caspase 6 and 9 cleavage, and a ROCK2-specific reduction in caspase 3 cleavage. Microarray analysis of ROCK knockdown lines revealed overlapping and unique control of global transcription by the paralogs, and a reduction in the transcriptional regulation of just under 50% of VEGF responsive genes. Finally, paralog knockdown in xenograft angiosarcoma tumors resulted in a significant reduction in tumor formation. Our data reveals that ROCK1 & 2 exhibit overlapping and unique roles in normal and dysfunctional endothelial cells, that alterations in cytoskeletal dynamics are capable of overriding mitogen activated transcription, and that therapeutic targeting of ROCK signaling may have profound impacts for targeting angiogenesis.
authors.affiliation: Ghosh Science and Technology Center, Department of Biology, Worcester State University, Worcester, Massachusetts, USA.
authors.forename: J
authors.initials: J
authors.lastname: Montalvo
authors.forename: C
authors.initials: C
authors.lastname: Spencer
authors.forename: A
authors.initials: A
authors.lastname: Hackathorn
authors.forename: K
authors.initials: K
authors.lastname: Masterjohn
authors.forename: A
authors.initials: A
authors.lastname: Perkins
authors.forename: C
authors.initials: C
authors.lastname: Doty
authors.forename: A
authors.initials: A
authors.lastname: Arumugam
authors.forename: P P
authors.initials: PP
authors.lastname: Ongusaha
authors.forename: R
authors.initials: R
authors.lastname: Lakshmanaswamy
authors.forename: J K
authors.initials: JK
authors.lastname: Liao
authors.forename: D C
authors.initials: DC
authors.lastname: Mitchell
authors.forename: B A
authors.initials: BA
authors.lastname: Bryan
mesh_terms: D000818:Animals; D002460:Cell Line; D045744:Cell Line, Tumor; D002465:Cell Movement / Q000502:physiology; D002470:Cell Survival; D042783:Endothelial Cells / Q000378:metabolism; D005786:Gene Expression Regulation / Q000187:drug effects; D055785:Gene Knockdown Techniques; D006394:Hemangiosarcoma / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D008545:Melanoma / Q000378:metabolism / Q000473:pathology; D051379:Mice; D018919:Neovascularization, Physiologic / Q000235:genetics / Q000502:physiology*; D034741:RNA, Small Interfering; D042461:Vascular Endothelial Growth Factor A / Q000235:genetics / Q000378:metabolism / Q000494:pharmacology; D023041:Xenograft Model Antitumor Assays; D054460:rho-Associated Kinases / Q000235:genetics / Q000378:metabolism*
chemical_list: D034741:RNA, Small Interfering; D042461:Vascular Endothelial Growth Factor A; C515854:Rock1 protein, mouse; C515855:Rock2 protein, mouse; D054460:rho-Associated Kinases