title: Mouse fibroblasts lacking RB1 function form spheres and undergo reprogramming to a cancer stem cell phenotype.
abstract: Activation of the RB1 pathway triggers the cell-cycle arrest that mediates cell-cell contact inhibition. Accordingly, mutation of all three RB1 family members leads to loss of contact inhibition and outgrowth of fibroblasts into spheres where cell-cell contacts predominate. We present evidence that such outgrowth triggers reprogramming to generate cells with properties of cancer stem cells. Fibroblasts with only a single RB1 mutation remain contact inhibited; however, if this contact inhibition is bypassed by forcing the RB1(-/-) cells to form spheres in suspension, cells with properties of cancer stem cells are also generated. These cells not only form tumors in nude mice but also generate differentiated cells. We propose that contact inhibition imposed by the RB1 pathway performs an unexpected tumor suppressor function by preventing cell outgrowth into structures where cells with properties of cancer stem cells can be generated from differentiated somatic cells in advancing cancers.
authors.affiliation: Molecular Targets Program, Brown Cancer Center, University of Louisville Health Sciences Center, Louisville, KY 40202, USA.
authors.forename: Yongqing
authors.initials: Y
authors.lastname: Liu
authors.forename: Brian
authors.initials: B
authors.lastname: Clem
authors.forename: Ewa K
authors.initials: EK
authors.lastname: Zuba-Surma
authors.forename: Shahenda
authors.initials: S
authors.lastname: El-Naggar
authors.forename: Sucheta
authors.initials: S
authors.lastname: Telang
authors.forename: Alfred B
authors.initials: AB
authors.lastname: Jenson
authors.forename: Yali
authors.initials: Y
authors.lastname: Wang
authors.forename: Hui
authors.initials: H
authors.lastname: Shao
authors.forename: Mariusz Z
authors.initials: MZ
authors.lastname: Ratajczak
authors.forename: Jason
authors.initials: J
authors.lastname: Chesney
authors.forename: Douglas C
authors.initials: DC
authors.lastname: Dean