E-cadherin represses anchorage-independent growth in sarcomas through both signaling and mechanical mechanisms

Abstract

42E-cadherin, an epithelial-specific cell-cell adhesion molecule, plays multiple roles in maintaining 43 adherens junctions, regulating migration and invasion, and mediating intracellular signaling. 44 Downregulation of E-cadherin is a hallmark of epithelial-mesenchymal transition (EMT) and 45 correlates with poor prognosis in multiple carcinomas. Conversely, upregulation of E-cadherin is 46 prognostic for improved survival in sarcomas. Yet, despite the prognostic benefit of E-cadherin 47 expression in sarcoma, the mechanistic significance of E-cadherin in sarcomas remains poorly 48 understood. Here, by combining mathematical models with wet-bench experiments, we identify 49 the core regulatory networks mediated by E-cadherin in sarcomas, and decipher their functional 50 consequences. Unlike in carcinomas, E-cadherin overexpression in sarcomas does not induce a 51 mesenchymal-epithelial transition (MET). However, E-cadherin acts to reduce both anchorage-52 independent growth and spheroid formation of sarcoma cells. Ectopic E-cadherin expression acts 53 to downregulate phosphorylated CREB (p-CREB) and the transcription factor, TBX2, to inhibit 54 anchorage-independent growth. RNAi-mediated knockdown of TBX2 phenocopies the effect of 55 E-cadherin on p-CREB levels and restores sensitivity to anchorage-independent growth in 56 sarcoma cells. Beyond its signaling role, E-cadherin expression in sarcoma cells can also 57 strengthen cell-cell adhesion and restricts spheroid growth through mechanical action. Together, 58 our results demonstrate that E-cadherin inhibits sarcoma aggressiveness by preventing 59 anchorage-independent growth. 60 61 62 63 64 65 66 67 68 69 70 71Sarcomas -deadly cancers that arise from tissues of a mesenchymal lineage -are highly 72 aggressive, with five year survival rates of just 66% (1). Despite their mesenchymal origin, some 73 sarcomas undergo phenotypic plasticity in which they gain "epithelial-like" traits (2)(3)(4). While 74 this transition to a more epithelial-like state is now being recognized as a feature of multiple 75 subtypes of soft tissue sarcoma and osteosarcoma (2)(3)(4), there are also a number of sarcoma 76 subtypes that are classically known to exhibit epithelioid features pathologically, including 77 synovial sarcoma (5), epithelioid sarcoma (6), and adamantinoma (7). One might expect the 78 acquisition of epithelial-like traits to be of little relevance in mesenchymal tumors, yet that is not 79 the case. Phenotypic plasticity is clinically important in sarcoma patients: Sarcoma patients 80 whose tumors express epithelial-like biomarkers have improved outcomes relative to patients 81 with more "mesenchymal-like" tumors (2)(3)(4)8). 82 Phenotypic plasticity observed in sarcomas is reminiscent of the phenomenon of 83 epithelial plasticity in carcinomas. Epithelial plasticity refers to reversible transitions between 84 epithelial and mesenchymal phenotypes. In carcinomas, the phenotypic transition to a more 85 mesenchymal-like state via an epithelial-mesenchyma...

Proteomic and transcriptomic profiling identifies mediators of anchorage-independent growth and roles of inhibitor of differentiation proteins in invasive lobular carcinoma

“…To test the previously described role of E-cadherin in anchorage independence 18 , 19 , 33 , 34 , we stably overexpressed E-cadherin in MM134 and SUM44 cells using a doxycycline-inducible system. Re-introduction of E-cadherin led to tighter cell–cell contacts by morphology and significantly diminished the growth of these ILC cell lines in both 2D and ULA culture, with stronger effects in ULA (Fig.…”

Role of Cadherins in Cancer—A Review

“…Such presentation of E-cadherin may aid in identifying recurrence risk patients in whom adjuvant therapy could be beneficial. E-cadherin overexpression in sarcomas reduces anchorage-independent growth and spheroid formation of sarcoma cells through downregulation of phosphorylated CREB1 (p-CREB) and the transcription factor, TBX2, thus inhibiting sarcoma aggressiveness by preventing anchorage-independent growth [ 111 ]. In metastatic colorectal cancer (mCRC), expression of E-cadherin in either cell membrane or cytoplasm was combined with strong vascular endothelial growth factor A (VEGF-A) staining as a predictor of disease outcome.…”

Inhibitory Effects of Doxycycline on Tumor Progression In vitro and on Metastases in Early-Stage Osteosarcoma Xenografts Mice.

“…Based on IHC staining, the primary tumors of both Dox − /Amp − and Dox + /Amp − xenografts were vimentin positive and E-cadherin negative (Fig. 4A), verifying the mesenchymal nature of OS [39,40,41].…”