ALPP Induces Epithelial-Mesenchymal Transition by Activating the Wnt/β-Catenin Signaling Pathway in Colorectal Cancer Cells.

[PURPOSE] Colorectal cancer (CRC) is a prevalent cancer worldwide, with metastasis significantly contributing to its high mortality and poor prognosis. This study focuses on the impact of Alkaline Phosphatase, Placental (ALPP) on epithelial-mesenchymal transition (EMT) in colorectal cancer cells and its role in the Wnt/β-catenin signaling pathway.

[PATIENTS AND METHODS] Differential ALPP expression was first interrogated in metastatic versus non-metastatic CRC samples from The Cancer Genome Atlas (TCGA-CRC) cohort. Functional validation was subsequently performed in vitro with HT29 and HCT116 cell lines engineered for ALPP overexpression or CRISPR/Cas9-mediated knockdown. Proliferation, migration and invasion were quantified by CCK-8, wound-healing and Transwell assays; EMT and Wnt/β-catenin signaling were assessed by Western blot.

[RESULTS] Bioinformatics analysis revealed significantly different ALPP expression between metastatic and non-metastatic patients. In vitro experiments further revealed that ALPP overexpression drives proliferation, invasion, migration and, consequently, metastasis of HT29 and HCT116 colorectal cancer cells, whereas ALPP knockdown abolishes these EMT-dependent effects. Increased ALPP expression resulted in increased levels of N-Cadherin, Vimentin, and Snail proteins, along with a decrease in E-cadherin protein expression, in contrast to findings following ALPP knockdown. Furthermore, ALPP overexpression was also associated with Wnt/β-catenin signaling pathway activation.

[CONCLUSION] ALPP was found to act as an oncogenic factor in colorectal cancer cell lines HT29 and HCT116, stimulating cell proliferation and facilitating EMT. Abnormal activation of the Wnt/β-catenin signaling pathway was also found to be linked to increased ALPP expression.