NID2

NID2 (Nidogen-2) functions as a context-dependent regulator of cell signaling whose re-expression suppresses tumor progression in epithelial cancers while its overexpression drives pathological osteogenic transdifferentiation in vascular smooth muscle cells (PMID:27793011, PMID:40937642). In nasopharyngeal and esophageal squamous carcinoma cells, NID2 re-expression suppresses clonogenic survival, migration, and liver metastasis by inhibiting the EGFR/Akt and integrin/FAK/PLCγ signaling pathways (PMID:27793011), and in lung cancer cells NID2 overexpression or promoter demethylation reduces viability, proliferation, migration, and invasion while increasing apoptosis and blocking xenograft tumorigenesis, identifying promoter hypermethylation as the mechanism of its silencing (PMID:30826972). In a distinct vascular context, NID2 overexpression promotes osteogenic transdifferentiation of smooth muscle cells through activation of an IGF2-ERK1/2 signaling axis, and its induction downstream of reduced soluble epoxide hydrolase activity (via elevated EETs) drives diabetic vascular calcification (PMID:40937642). Beyond these signaling phenotypes, no structural or biochemical reconstitution of NID2 function has been characterized in the available corpus.

1. 2016 Medium

   Established NID2 as a metastasis suppressor in squamous carcinomas and placed it upstream of defined oncogenic signaling, answering whether its loss has a causal role in tumor spread.

   Evidence NID2 re-expression in NPC and ESCC cell lines with clonogenic/migration assays, in vivo liver metastasis model, and pathway analysis

   PMID:27793011

   Open questions at the time

   • No direct biochemical demonstration of how NID2 engages EGFR or integrin to inhibit signaling
   • Single lab; no reciprocal loss-of-function in patient-derived models
   • Mechanism of NID2 silencing not addressed in this study
2. 2019 Medium

   Extended the tumor-suppressor model to lung cancer and linked NID2 silencing causally to promoter hypermethylation, addressing why NID2 is lost in epithelial tumors.

   Evidence NID2 overexpression and demethylation in lung cancer cell lines with CCK-8, colony formation, transwell, wound-healing, flow cytometry, and nude mouse xenografts

   PMID:30826972

   Open questions at the time

   • Downstream effector pathways in lung cancer not mechanistically dissected
   • Direct demethylation-driven re-expression not shown at the endogenous promoter in vivo
   • Single lab
3. 2025 Medium

   Revealed a context-opposite, pro-pathogenic role for NID2 in vascular calcification and connected it to an upstream EET/sEH input and downstream IGF2-ERK1/2 output, answering how NID2 contributes to diabetic vascular disease.

   Evidence Ephx2 (sEH) knockout mouse with siRNA, pharmacologic inhibition, AAV9-mediated NID2 overexpression rescue, alizarin red/Von Kossa staining, and Western blotting

   PMID:40937642

   Open questions at the time

   • How NID2 activates IGF2-ERK1/2 is not biochemically defined
   • Mechanism by which EETs lower NID2 expression unknown
   • Single lab; reconciliation with the tumor-suppressor context not addressed

• How NID2 produces opposite outcomes (signaling suppression in epithelial cancers versus osteogenic signaling activation in vascular smooth muscle) at the molecular level remains unresolved.
• No structural or reconstituted biochemical mechanism for NID2 signaling modulation
• No identified direct receptor or matrix partner mediating its effects
• Cell-type determinants of NID2's opposite roles undefined