Establishment and Characterization of a new Human Extragonadal Germ Cell Line, SEM-1, and its Comparison With TCam-2 and JKT-1

Abstract

OBJECTIVE To describe the establishment and characterization of a human cell line, SEM-1, from a patient diagnosed with a mediastinal seminoma. METHODS A small percentage of germ cell tumors develop as primary lesions in extragonadal sites, and the etiology of these tumors is poorly understood. Currently, only 2 cell lines from seminoma patients have been reported, JKT-1 and TCam-2, both derived from the testis. The cell line was characterized by heterotransplantation in Nude mice, cytogenetic studies, immunohistochemical and flow cytometry staining for germ cell tumor biomarkers, quantitative reverse-transcription polymerase chain reaction for cancer testis antigen expression, and BRAF mutation screening with quantitative polymerase chain reaction. RESULTS Characterization studies confirmed the human extragonadal seminoma origin of SEM-1 and demonstrated that it had more features in common with TCam-2 than JKT-1. Specifically, SEM-1 was positive for Sal-like protein 4 (SALL-4), activator protein-2γ (AP-2γ), and cytokeratin CAM5.2, and demonstrated heterogeneous expression of stem cell markers octamer-binding transcription factor 3/4, NANOG, c-KIT, SOX17, and SOX2. Cytogenetic analysis revealed a hypotriploid chromosome number, with multiple copies of 12p, but isochromosome 12p and the BRAF mutation V600E were not identified. The cell lines also did not contain the BRD4/NUT gene rearrangement [t(15,19)] seen in midline carcinomas nor did they contain overexpressed nuclear protein in testis (NUT) genes. CONCLUSION SEM-1 is the first cell line derived from an extragonadal germ cell tumor showing intermediate characteristics between seminoma and nonseminoma, and as such, is an important model to study the molecular pathogenesis of this malignancy.

Testicular orphan receptor 4 promotes tumor progression and implies poor survival through AKT3 regulation in seminoma

“…Mechanistically, TR4 may exert its function through upregulation of AKT3 at the transcriptional level. It is a pity that we only used Tcam‐2 cell line in our cell line studies for lacking of the other pure seminoma cell line in the world now . In our future research, we will continue to explore the role of TR4 and AKT3 in the other testicular germ cell cancer, such as teratoma and choriocarcinoma, to obtain a comprehensive understanding of TR4 function in testicular tumors.…”

The plasticity of germ cell cancers and its dependence on the cellular microenvironment

“…Most studies analysing the plasticity of seminomas are based on in vitro and in vivo experiments utilizing the seminomaderived cell line TCam-2. TCam-2 is the only available cell line, which reliably resembles a seminoma / GCNIS / PGC in vitro [29][30][31][32][33][34], whereas the suitability of the cell lines JKT-1 and SEM1 as a proxy for seminomas is questionable, although they were derived from tumours of patients diagnosed with seminoma [30,35,36].…”

TDRG1 regulates chemosensitivity of seminoma TCam-2 cells to cisplatin via PI3K/Akt/mTOR signaling pathway and mitochondria-mediated apoptotic pathway

“…Hence, to date, only 3 lines have been reported and none of them can be purchased. 18 The human TCam-2 cell line was primarily derived from a testicular tumor sample of pure classical seminoma in 1992. 19 In this study, TCam-2 cells (kindly gifted from Dr. Riko Kitazawa, Department of Diagnostic Pathology, Ehime University Hospital, Matsuyama, Japan) were maintained in complete medium (Roswell Park Memorial Institute Medium-1640 with 10% fetal calf serum) in a humidified 5% CO 2 , 37 C incubator.…”