Establishment and characterization of two novel patient-derived cell lines from giant cell tumor of bone: NCC-GCTB8-C1 and NCC-GCTB9-C1

Giant cell tumor of bone (GCTB) is a rare osteolytic bone tumor consisting of mononuclear stromal cells, macrophages, and osteoclast-like giant cells. Although GCTB predominantly exhibits benign behavior, the tumor carries a significant risk of high local recurrence. Furthermore, GCTB can occasionally undergo malignant transformation and distal metastasis, making it potentially fatal. The standard treatment is complete surgical resection; nonetheless, an optimal treatment strategy for advanced GCTB remains unestablished, necessitating expanded preclinical research to identify appropriate therapeutic options. However, only one GCTB cell line is publicly available from a cell bank for research use worldwide. The present study reports the establishment of two novel cell lines, NCC-GCTB8-C1 and NCC-GCTB9-C1, derived from the primary tumor tissues of two patients with GCTB. Both cell lines maintained the hallmark mutation in the H3-3A gene, which is associated with tumor formation and development in GCTB. Characterization of these cell lines revealed their steady growth, spheroid-formation capability, and invasive traits. Potential therapeutic agents were identified via extensive drug screening of the two cell lines and seven previously established GCTB cell lines. Among the 214 antitumor agents tested, romidepsin, a histone deacetylase inhibitor, and mitoxantrone, a topoisomerase inhibitor, were identified as potential therapeutic agents against GCTB. Conclusively, the establishment of NCC-GCTB8-C1 and NCC-GCTB9-C1 provides novel and crucial resources that are expected to advance GCTB research and potentially revolutionize treatment strategies.