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Updated: Mar 16, 2026
Three-Dimensional Bone Extracellular Matrix Model for Osteosarcoma
Published on: April 12, 2019
Sclerostin expression in skeletal sarcomas
Jia Shen1, Carolyn A Meyers2, Swati Shrestha2
1Division of Growth and Development and Section of Orthodontics, School of Dentistry, University of California, Los Angeles, CA 90095; Department of Pathology and Laboratory Medicine, David Geffen School of Medicine, University of California, Los Angeles, CA 90095.
Abstract:
Sclerostin (SOST) is an extracellular Wnt signaling antagonist which negatively regulates bone mass. Despite this, the expression and function of SOST in skeletal tumors remain poorly described. Here, we first describe the immunohistochemical staining pattern of SOST across benign and malignant skeletal tumors with bone or cartilage matrix (n=68 primary tumors). Next, relative SOST expression was compared to markers of Wnt signaling activity and osteogenic differentiation across human osteosarcoma (OS) cell lines (n=7 cell lines examined). Results showed immunohistochemical detection of SOST in most bone-forming tumors (90.2%; 46/51) and all cartilage-forming tumors (100%; 17/17). Among OSs, variable intensity and distribution of SOST expression were observed, which highly correlated with the presence and degree of neoplastic bone. Patchy SOST expression was observed in cartilage-forming tumors, which did not distinguish between benign and malignant tumors or correlate with regional morphologic characteristics. Finally, SOST expression varied widely between OS cell lines, with more than 97-fold variation. Among OS cell lines, SOST expression positively correlated with the marker of osteogenic differentiation alkaline phosphatase and did not correlate well with markers of Wnt/β-catenin signaling activity. In summary, SOST is frequently expressed in skeletal bone- and cartilage-forming tumors. The strong spatial correlation with bone formation and the in vitro expression patterns are in line with the known functions of SOST in nonneoplastic bone, as a feedback inhibitor on osteogenic differentiation. With anti-SOST as a potential therapy for osteoporosis in the near future, its basic biologic and phenotypic consequences in skeletal tumors should not be overlooked.
Insights
Sclerostin (SOST) is frequently found in bone and cartilage tumors, acting as a feedback inhibitor of osteogenic differentiation. Its expression in osteosarcoma correlates with bone formation, not Wnt signaling activity.
Area of Science:
- Oncology
- Endocrinology
- Biochemistry
Background:
- Sclerostin (SOST) is a key antagonist of Wnt signaling, regulating bone mass.
- The role and expression of SOST in skeletal tumors are not well understood.
- Understanding SOST in tumors is crucial given its therapeutic potential for osteoporosis.
Purpose of the Study:
- To investigate the expression pattern of SOST in benign and malignant skeletal tumors.
- To compare SOST expression with Wnt signaling activity and osteogenic differentiation markers in osteosarcoma cell lines.
Main Methods:
- Immunohistochemical staining of SOST in 68 primary skeletal tumors.
- Quantitative analysis of SOST expression in 7 human osteosarcoma cell lines.
- Correlation analysis with Wnt signaling markers and alkaline phosphatase.
Main Results:
- SOST was detected in 90.2% of bone-forming and 100% of cartilage-forming tumors.
- SOST expression in osteosarcoma correlated with neoplastic bone presence and degree.
- SOST expression in cell lines varied widely and correlated with osteogenic differentiation, not Wnt signaling.
Conclusions:
- SOST is commonly expressed in skeletal bone- and cartilage-forming tumors.
- SOST functions as a feedback inhibitor of osteogenic differentiation in these tumors.
- The biological consequences of SOST in skeletal tumors warrant further investigation for potential therapeutic implications.
