Establishment and characterization of two novel patient-derived cell lines from giant cell tumor of bone.

Giant cell tumor of bone (GCTB) is a rare bone tumor with osteolytic features, composed of stromal cells with a monotonous appearance, macrophages, and osteoclast-like giant cells. GCTB is commonly associated with a pathogenic mutation in the H3-3A gene. While complete surgical resection is the standard cure for GCTB, it often results in local recurrence and, rarely, metastasis. Thus, an effective multidisciplinary treatment approach is necessary. Although patient-derived cell lines is an essential tool for investigating novel treatment strategies, there are only four GCTB cell lines available in public cell banks. Therefore, this study aimed to establish novel GCTB cell lines and successfully created NCC-GCTB6-C1 and NCC-GCTB7-C1 cell lines from two patients' surgically removed tumor tissues. These cell lines exhibited H3-3A gene mutations, consistent proliferation, and invasive properties. After characterizing their behaviors, we performed high-throughput screening of 214 anti-cancer drugs for NCC-GCTB6-C1 and NCC-GCTB7-C1 and integrated their screening data with those of NCC-GCTB1-C1, NCC-GCTB2-C1, NCC-GCTB3-C1, NCC-GCTB4-C1, and NCC-GCTB5-C1 that we previously established. We identified histone deacetylase inhibitor romidepsin as a possible treatment for GCTB. These findings suggest that NCC-GCTB6-C1 and NCC-GCTB7-C1 could be valuable tools for preclinical and basic research on GCTB.