SRC-like adaptor protein negatively regulates Wnt signaling in intrahepatic cholangiocarcinoma

Area of Science:

• Oncology
• Molecular Biology
• Cell Biology

Background:

• Intrahepatic cholangiocarcinoma (IHCC) molecular mechanisms remain largely unknown.
• SRC-like adaptor protein (SLAP) is implicated in various cancers but its role in IHCC is uncharacterized.

Purpose of the Study:

• To investigate the role of SLAP in IHCC.
• To determine the effect of SLAP on IHCC cell proliferation, cell cycle, and Wnt signaling pathway.

Main Methods:

• Quantitative analysis of SLAP expression in IHCC tissues and cells.
• Overexpression of SLAP in IHCC cell lines (RBE and Huh28) using adenovirus vectors.
• Cell proliferation assays, cell cycle analysis, and wound healing/invasion assays.
• Wnt signaling pathway activity assessment using TOPflash/FOPflash reporter assays and Western blotting for Wnt target genes.

Main Results:

• SLAP expression was significantly decreased in IHCC tissues and cells compared to controls.
• SLAP overexpression inhibited IHCC cell proliferation, induced G1 cell cycle arrest, and reduced migration and invasion.
• SLAP overexpression suppressed Wnt signaling pathway activity, evidenced by reduced TOPflash activity and decreased expression of Wnt target genes (β-catenin, c-Myc, CD44, Slug, Vimentin, MMP-9).

Conclusions:

• Reduced SLAP expression is a novel finding in IHCC and is associated with enhanced tumor progression.
• SLAP functions as a tumor suppressor in IHCC by inhibiting cell proliferation, migration, and invasion.
• SLAP exerts its tumor-suppressive effects, at least in part, by negatively regulating the Wnt/β-catenin signaling pathway.