PDCD7

PDCD7 transcriptionally activates E-cadherin expression by binding a GC-box element in the E-cadherin promoter; CRISPR knockout of PDCD7 increases in vitro oncogenicity and neck nodal metastasis in mice while reducing E-cadherin levels, and PDCD7 is itself a direct target of miR-134 (PMID:29971778). Overexpression of the mouse ortholog (ES18) in T-cell lymphoma promotes apoptotic cell death, though the molecular pathway linking PDCD7 to apoptosis has not been defined (PMID:10037816).

1. 1999 Low

   Initial cloning revealed that PDCD7 overexpression could promote apoptosis in T-cell lymphoma and that its transcript was selectively regulated by apoptotic stimuli, establishing a first link between PDCD7 and programmed cell death without placing it in a defined pathway.

   Evidence Transient overexpression in mouse T-cell lymphoma with apoptosis readout; transcript regulation during dexamethasone- and staurosporine-induced apoptosis

   PMID:10037816

   Open questions at the time

   • Overexpression-only phenotype without loss-of-function validation or pathway placement
   • No molecular mechanism linking PDCD7 to apoptotic signaling identified
   • Single lab observation not independently confirmed
2. 2018 Medium

   PDCD7 was shown to act as a transcriptional activator of E-cadherin through a GC-box in its promoter and to suppress metastasis in vivo, while being itself regulated by miR-134, establishing a miR-134–PDCD7–E-cadherin axis in cancer progression.

   Evidence Luciferase reporter assays with wild-type/mutant constructs, CRISPR knockout, in vivo mouse nodal metastasis model, promoter GC-box functional analysis

   PMID:29971778

   Open questions at the time

   • Findings originate from a single laboratory; independent replication is lacking
   • Mechanism by which PDCD7 binds or activates the GC-box (direct DNA binding vs. cofactor recruitment) not resolved
   • Relationship between the E-cadherin–activating function and the earlier apoptotic role remains unexplored

• It remains unknown whether PDCD7 directly binds DNA, what structural domains mediate its transcriptional activity, and whether its pro-apoptotic and tumor-suppressive functions reflect the same or distinct molecular mechanisms.
• No structural or biochemical characterization of PDCD7 protein
• No identified protein domains mediating transcriptional activation
• No interactome or proteomics data placing PDCD7 in a defined complex