A role for iron in Wnt signalling.

Area of Science:

• Oncology
• Molecular Biology
• Cell Biology

Background:

• Emerging evidence links iron to carcinogenesis, particularly colorectal cancer.
• The role of iron in Wnt signaling, a key oncogenic pathway, remains unstudied.

Purpose of the Study:

• To investigate the impact of iron loading on Wnt signaling.
• To determine if iron-mediated Wnt signaling is dependent on Adenomatous Polyposis Coli (APC) status.

Main Methods:

• Utilized cell lines with mutant APC (Caco-2, SW480) and wild-type APC (HEK-293, primary fibroblasts).
• Assessed Wnt signaling via TOPFLASH reporter activity, c-myc and Nkd1 mRNA expression, and cellular proliferation.
• Investigated the role of beta-catenin and E-cadherin in iron-mediated Wnt signaling.

Main Results:

• Iron loading increased Wnt signaling, c-myc/Nkd1 expression, and proliferation in mutant APC cells (Caco-2, SW480).
• Wild-type APC cells (HEK-293, fibroblasts) showed no response to iron loading.
• Restoring wild-type APC in SW480 cells abolished iron-mediated Wnt signaling.
• LS174T cells (wild-type APC, mutant beta-catenin) responded to iron, suggesting iron regulates beta-catenin.
• E-cadherin status did not influence iron-mediated Wnt signaling.

Conclusions:

• Excess iron may exacerbate tumorigenesis in the context of APC loss.
• Iron's effect on Wnt signaling appears to be mediated through beta-catenin regulation.
• These findings highlight a potential mechanism linking iron overload to cancer development, especially in APC-deficient cancers.