Active β-catenin promotes aggressive spread of childhood bone cancer

A new research paper was recently published in Volume 17 of Genes & Cancer, titled "Active Beta-Catenin (ABC) promotes an invasive phenotype in pediatric osteosarcoma."

The study was led by co-first authors Kristin Hinton and Saima Ghafoor, and corresponding author Sujata Persad from the Department of Paediatrics, Faculty of Medicine and Dentistry at the University of Alberta, Canada.

Osteosarcoma is the most common primary bone cancer in children and adolescents. Despite advances in surgery and chemotherapy, survival rates have improved little over the past two decades, particularly for patients whose cancer spreads to distant organs such as the lungs. Understanding the molecular mechanisms that drive tumor progression remains a major priority in the search for more effective treatments.

In this study, researchers investigated the role of activated β-catenin (ABC), a highly active form of the β-catenin protein that participates in Wnt signaling, a pathway known to influence cancer development and progression. Previous work had shown that ABC levels are elevated in aggressive osteosarcoma cells, but whether ABC directly contributes to disease progression remained unclear.

To address this question, the team engineered osteosarcoma cells to express either ABC or conventional β-catenin and compared their behavior in a series of laboratory experiments. The results revealed a striking difference between the two proteins.

Cells expressing ABC demonstrated significantly greater invasive capacity than control cells and closely resembled highly metastatic osteosarcoma cell lines. In contrast, overexpression of standard β-catenin did not produce the same effect. ABC also enhanced anchorage-independent growth, a hallmark of cancer aggressiveness that enables tumor cells to survive and proliferate without normal attachment signals.

Further experiments showed that ABC substantially increased Wnt pathway transcriptional activity. The researchers observed elevated expression of matrix metalloproteinases MMP-2 and MMP-9, enzymes that help cancer cells break down surrounding tissue and invade new sites. These molecular changes provide a potential explanation for the enhanced invasive behavior observed in ABC-expressing cells.

The investigators also found that ABC promoted cancer-associated traits more effectively than β-catenin itself. While both proteins activated Wnt signaling to some extent, ABC consistently produced stronger transcriptional responses and more pronounced effects on tumor cell behavior.

"Cumulatively, these results suggest that ABC plays a role in OS progression, and this may be distinct from the role of β-Catenin."

According to the authors, these findings suggest that ABC may represent a previously underappreciated driver of osteosarcoma progression. Because ABC appears to promote aggressive tumor behavior more directly than β-catenin, therapies designed to specifically block ABC formation or activity could offer a more targeted approach than broader inhibition of the Wnt signaling pathway.

The researchers also note that elevated nuclear levels of ABC may have value as a prognostic biomarker, potentially helping clinicians identify tumors with a greater likelihood of progression or metastasis.

Overall, the study provides the first direct evidence that activated β-catenin promotes an invasive phenotype in osteosarcoma cells. The findings improve our understanding of how osteosarcoma progresses and highlight ABC as a promising therapeutic target and potential biomarker for this aggressive pediatric cancer.