Myxofibrosarcoma (MFS) is a highly aggressive malignancy with complex karyotypes and a postoperative recurrence tendency, owing to its strong invasiveness. Although systemic chemotherapy is considered in patients with unresectable MFS, the efficacy of conventional chemotherapy is hitherto unclear. Recently, drug screening analysis using a large number of tumor cell lines has been attempted to discover novel therapeutic candidate drugs for common cancers. However, the number of MFS cell lines is extremely small because of its low incidence—this hinders the conduction of screening studies and slows down the development of therapeutic drugs. To overcome this problem, we established a novel MFS cell line, NCC-MFS5-C1, which was shown to harbor typical MFS genetic abnormalities and thus had useful properties for in vitro studies. We conducted the largest integrated screening analysis of 210 drugs using NCC-MFS5-C1 cells along with four MFS cell lines, which we previously reported. Bortezomib (a proteasome inhibitor) and romidepsin (a histone deacetylase inhibitor) showed stronger antitumor effects than the standard drug, doxorubicin. Therefore, the NCC-MFS5-C1 cell line can potentially contribute to elucidating MFS pathogenesis and developing a novel MFS treatment.

Pseudomyxoma peritonei (PMP) is the intraperitoneal accumulation of mucus due to a mucinous tumor. PMP predominantly occurs in low-grade carcinomas. The incidence rate of PMP is one to two cases per million people per year. The standard therapy of PMP comprises complete cytoreductive surgery and hyperthermic intraperitoneal chemotherapy. PMP recurs in about 50% of patients, and 30–40% are unable to receive the standard treatment because of its invasiveness. Therefore, novel therapies are of the utmost necessity. For basic and pre-clinical research, patient-derived cell lines are essential resources. However, only two PMP cell lines have been reported. Thus, we established a novel PMP cell line from resected metastatic PMP tissue. The cell line, named NCC-PMP1-C1, was maintained for more than 5 months and was passaged 25 times. NCC-PMP1-C1 cells demonstrated multiple amplifications and deletions, slow growth, tumorigenic ability, and dissemination of tumor cells in nude mice. We also used NCC-PMP1-C1 cells to screen drugs, which demonstrated a significant response to daunorubicin HCl, homoharringtonine, mitomycin C, and ponatinib. The NCC-PMP1-C1 cell line is the first PMP cell line derived from metastasized tissue and will be a potential resource for basic and pre-clinical research of metastasized PMP.

Dedifferentiated liposarcoma (DDLPS) is a highly malignant sarcoma characterized by the co-amplification of MDM2 and CDK4. Although systemic chemotherapy is recommended for unresectable or metastatic cases, DDLPS is insensitive to conventional chemotherapy, leading to an unfavorable prognosis. Therefore, novel treatment methods are urgently required. Patient-derived cell lines are essential in preclinical studies. Recently, large-scale screening studies using a number of cell lines have been actively conducted for the development of new therapeutic drugs. However, the DDLPS cell line cannot be obtained from public cell banks owing to its rarity, hindering screening studies. As such, novel DDLPS cell lines need to be established. Accordingly, this study aimed to establish a novel DDLPS cell line from surgical specimens. The cell line was named NCC-DDLPS4-C1. NCC-DDLPS4-C1 cells retained copy number alterations corresponding to the original tumors. Further, the cells demonstrated constant growth, spheroid formation, and equivalent invasiveness to MG63 osteosarcoma cells. We also conducted drug screening and integrated the results with those of the previously reported DDLPS cell lines. Consequently, we identified the histone deacetylase inhibitor romidepsin as a novel candidate drug. In conclusion, the NCC-DDLPS4-C1 cell line is a useful tool for the basic study of DDLPS.

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