title: Cell growth density modulates cancer cell vascular invasion via Hippo pathway activity and CXCR2 signaling.
abstract: Metastasis of cancer cells involves multiple steps, including their dissociation from the primary tumor and invasion through the endothelial cell barrier to enter the circulation and finding their way to distant organ sites where they extravasate and establish metastatic lesions. Deficient contact inhibition is a hallmark of invasive cancer cells, yet surprisingly the vascular invasiveness of commonly studied cancer cell lines is regulated by the density at which cells are propagated in culture. Cells grown at high density were less effective at invading an endothelial monolayer than cells grown at low density. This phenotypic difference was also observed in a zebrafish model of vascular invasion of cancer cells after injection into the yolk sac and extravasation of cancer cells into tissues from the vasculature. The vascular invasive phenotypes were reversible. A kinome-wide RNA interference screen was used to identify drivers of vascular invasion by panning small hairpin RNA (shRNA) library-transduced noninvasive cancer cell populations on endothelial monolayers. The selection of invasive subpopulations showed enrichment of shRNAs targeting the large tumor suppressor 1 (LATS1) kinase that inhibits the activity of the transcriptional coactivator yes-associated protein (YAP) in the Hippo pathway. Depletion of LATS1 from noninvasive cancer cells restored the invasive phenotype. Complementary to this, inhibition or depletion of YAP inhibited invasion in vitro and in vivo. The vascular invasive phenotype was associated with a YAP-dependent upregulation of the cytokines IL6, IL8 and C-X-C motif ligand 1, 2 and 3. Antibody blockade of cytokine receptors inhibited invasion and confirmed that they are rate-limiting drivers that promote cancer cell vascular invasiveness and could provide therapeutic targets.
authors.affiliation: Lombardi Cancer Center, Georgetown University, Washington, DC, USA.
authors.forename: G M
authors.initials: GM
authors.lastname: Sharif
authors.affiliation: Lombardi Cancer Center, Georgetown University, Washington, DC, USA.
authors.forename: M O
authors.initials: MO
authors.lastname: Schmidt
authors.affiliation: Lombardi Cancer Center, Georgetown University, Washington, DC, USA.
authors.forename: C
authors.initials: C
authors.lastname: Yi
authors.affiliation: Lombardi Cancer Center, Georgetown University, Washington, DC, USA.
authors.forename: Z
authors.initials: Z
authors.lastname: Hu
authors.affiliation: Lombardi Cancer Center, Georgetown University, Washington, DC, USA.
authors.forename: B R
authors.initials: BR
authors.lastname: Haddad
authors.affiliation: Lombardi Cancer Center, Georgetown University, Washington, DC, USA.
authors.forename: E
authors.initials: E
authors.lastname: Glasgow
authors.affiliation: Lombardi Cancer Center, Georgetown University, Washington, DC, USA.
authors.forename: A T
authors.initials: AT
authors.lastname: Riegel
authors.affiliation: Lombardi Cancer Center, Georgetown University, Washington, DC, USA.
authors.forename: A
authors.initials: A
authors.lastname: Wellstein
mesh_terms: D048868:Adaptor Proteins, Signal Transducing / Q000235:genetics / Q000378:metabolism*; D000818:Animals; D017209:Apoptosis; D015153:Blotting, Western; D001943:Breast Neoplasms / Q000235:genetics / Q000378:metabolism* / Q000473:pathology*; D002453:Cell Cycle; D002465:Cell Movement; D049109:Cell Proliferation; D016207:Cytokines / Q000235:genetics / Q000378:metabolism; D004730:Endothelium, Vascular / Q000378:metabolism / Q000473:pathology*; D005260:Female; D015972:Gene Expression Regulation, Neoplastic; D061307:Human Umbilical Vein Endothelial Cells; D006801:Humans; D051379:Mice; D008819:Mice, Nude; D009361:Neoplasm Invasiveness; D010750:Phosphoproteins / Q000235:genetics / Q000378:metabolism*; D010766:Phosphorylation; D017346:Protein Serine-Threonine Kinases / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D034622:RNA Interference; D012333:RNA, Messenger / Q000235:genetics; D060888:Real-Time Polymerase Chain Reaction; D023063:Receptors, Interleukin-8B / Q000235:genetics / Q000378:metabolism*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014157:Transcription Factors; D014407:Tumor Cells, Cultured; D023041:Xenograft Model Antitumor Assays; D000091102:YAP-Signaling Proteins; D015027:Zebrafish
chemical_list: D048868:Adaptor Proteins, Signal Transducing; D016207:Cytokines; D010750:Phosphoproteins; D012333:RNA, Messenger; D023063:Receptors, Interleukin-8B; D014157:Transcription Factors; D000091102:YAP-Signaling Proteins; C088374:YAP1 protein, human; C092745:LATS1 protein, human; D017346:Protein Serine-Threonine Kinases