ANKDD1A

ANKDD1A functions as a negative regulator of the hypoxic transcriptional response in glioma, acting as a tumor suppressor whose loss favors hypoxic adaptation of tumor cells (PMID:30082910, PMID:21962230). Mechanistically, ANKDD1A directly binds FIH1 (factor inhibiting HIF-1) and upregulates its activity, which destabilizes HIF1α by shortening its half-life and represses HIF1α-driven transcription; the downstream consequences include reduced glucose uptake and lactate production, inhibition of autophagy, and induction of apoptosis in glioblastoma cells under hypoxia (PMID:30082910). ANKDD1A expression is suppressed in primary glioma through promoter hypermethylation and altered histone modifications, and can be restored via miR-185-mediated targeting of DNMT1 (PMID:21962230). Beyond its FIH1/HIF1α axis in glioma, no further molecular detail has been characterized in the available corpus.

1. 2011 Medium

   Established that ANKDD1A is epigenetically silenced in glioma, framing it as a candidate tumor suppressor whose loss is driven by aberrant promoter methylation rather than mutation.

   Evidence Genome-wide MeDIP-chip, MassARRAY methylation validation, ChIP, and miR-185 overexpression in primary glioma samples and cell lines

   PMID:21962230

   Open questions at the time

   • Does not establish the molecular function of the ANKDD1A protein itself
   • Causal contribution of silencing to tumorigenesis not directly demonstrated
   • miR-185/DNMT1 link to ANKDD1A is correlative restoration, not a defined regulatory circuit
2. 2018 Medium

   Defined the molecular mechanism by which ANKDD1A acts, showing it binds FIH1 to suppress HIF1α signaling and reprogram hypoxic metabolism, autophagy, and survival in glioblastoma.

   Evidence Co-immunoprecipitation for FIH1 interaction plus HIF1α half-life, glucose uptake, lactate, autophagy, and apoptosis assays in GBM cells under hypoxia

   PMID:30082910

   Open questions at the time

   • Single-lab finding without independent replication
   • Structural basis of the ANKDD1A–FIH1 interaction and how it upregulates FIH1 activity not resolved
   • Whether ANKDD1A acts in tissues outside glioma is untested

• Whether ANKDD1A has functions beyond the FIH1/HIF1α axis and a role in normal physiology remains unknown.
• No structural or domain-level mechanism for FIH1 activation
• No in vivo tumor suppression demonstration in the corpus
• No partners or substrates beyond FIH1 identified