Formation of spherical cancer stem-like cell colonies with resistance to chemotherapy drugs in the human malignant fibrous histiocytoma NMFH-1 cell line.

Various human cancers have been revealed to contain cancer stem-like cells (CSCs) and the spherical colonies that possess stem-like properties and cancer-initiating abilities. Malignant fibrous histiocytoma (MFH) is a common soft-tissue sarcoma, and is considered to be a myxoma due to the observed high-grade lesions. In the present study, the spherical colonies were isolated from a human MFH cell line NMFH-1 using the sphere culture system. These colonies demonstrated stem-like properties, with the ability of self-renewal and strong drug-resistance to doxorubicin and cisplatin. In addition, verapamil, an adenosine triphosphate binding cassette protein transporter protein (ABCG2) inhibitor, enhanced the efficacy of the aforementioned chemotherapy agents. These colonies also demonstrated an increased expression of embryonic stem genes, including Oct3/4, signal transducer and activator of transcription 3, sex determining region Y-box 10 and ABCG2, and stem cell-associated surface markers, such as cluster of differentiation (CD)44 and CD133. These results indicated that NMFH-1 lesions contain cancer stem-like cell populations that demonstrate strong drug resistance, and verapamil enhanced the efficacy of the chemotherapy agents.