MDCK cells expressing constitutively active Yes-associated protein (YAP) undergo apical extrusion depending on neighboring cell status

Abstract

Cell competition is a cell-cell interaction by which a cell compares its fitness to that of neighboring cells. The cell with the relatively lower fitness level is the “loser” and actively eliminated, while the cell with the relatively higher fitness level is the “winner” and survives. Recent studies have shown that cells with high Yes-associated protein (YAP) activity win cell competitions but the mechanism is unknown. Here, we report the unexpected finding that cells overexpressing constitutively active YAP undergo apical extrusion and are losers, rather than winners, in competitions with normal mammalian epithelial cells. Inhibitors of metabolism-related proteins such as phosphoinositide-3-kinase (PI3K), mammalian target of rapamycin (mTOR), or p70S6 kinase (p70S6K) suppressed this apical extrusion, as did knockdown of vimentin or filamin in neighboring cells. Interestingly, YAP-overexpressing cells switched from losers to winners when co-cultured with cells expressing K-Ras (G12V) or v-Src. Thus, the role of YAP in deciding cell competitions depends on metabolic factors and the status of neighboring cells.

Hippo pathway controls cell adhesion and context‐dependent cell competition to influence skin engraftment efficiency

“…S2). These results corroborate previously described results for MDCK cells (38) and extend them to PAM keratinocytes and NIH3T3 fibroblasts—that is, mammalian cells expressing activated YAP1 can be losers in cell competitions with normal cells, a finding that stands in contrast to the case in Drosophila .…”

“…A context‐dependent switch between losing and winning in cell competitions is not a new observation. We previously reported that MDCK cells overexpressing active YAP1 became losers when cocultured with WT cells in vitro but were winners when cocultured with cells expressing K‐Ras (G12V) or v‐Src (38, 47). The findings we have presented in this manuscript indicate that a major reason for winner‐loser switching may be a difference in the ability of a cell to adhere to the surface of a culture vessel or matrix.…”

“…To determine the role of YAP1 during mammalian cell competition, we examined PAM (mouse keratinocyte), MDCK (dog kidney), and NIH3T3 (mouse fibroblast) cell lines engineered to overexpress the YAP5SA protein. In this mutant form of YAP1, the 5 Ser residues normally phosphorylated by Hippo signaling are replaced with Ala (38). As a result, all 3 cell lines can be induced to express a constitutively active form of YAP1 in a Dox-dependent manner (Supplemental Fig.…”

Elimination of oncogenic cells that regulate epithelial homeostasis in Drosophila

“…In particular, normal epithelial tissues often exert anti-tumor effects against neighboring cells that acquire oncogenic alterations (Bissell & Radisky, 2001). For instance, oncogenic cells activating an oncogene such as Ras, Src, ErbB2, or YAP are eliminated from the epithelial layer when surrounded by wild-type cells in mammals (Chiba et al, 2016;Hogan et al, 2009;Kajita et al, 2010;Leung & Brugge, 2012). Similarly, oncogenic cells mutant for an evolutionarily conserved apico-basal polarity gene such as scribble (scrib) or discs large (dlg) are eliminated from the Drosophila imaginal epithelium when surrounded by wild-type cells (Brumby & Richardson, 2003;Woods & Bryant, 1991).…”

Prostaglandin E2 and its receptor EP2 trigger signaling that contributes to YAP‐mediated cell competition

“…In mouse fibroblast NIH3T3 cells, cell competition resulting in apoptosis was reportedly dependent on TEAD activity (Mamada, Sato, Ota, & Sasaki, 2015). We subsequently showed that MDCK cells and mouse hepatocytes also undergo YAP-induced competition (Chiba et al, 2016;Miyamura et al, 2017). We generated doxycycline (Dox)-inducible YAP (5SA)-expressing MDCK cells [YAP (5SA) cells] and showed that they succumb to apical extrusion when surrounded by normal MDCK cells.…”