The seminoma cell line TCam‐2 is sensitive to HDAC inhibitor depsipeptide but tolerates various other chemotherapeutic drugs and loss of NANOG expression

Abstract

Seminomas and embryonal carcinomas (EC) are both type II germ cell tumor (GCT) entities and develop from the same precursor lesion (carcinoma-in situ, CIS). However, they show significant differences in growth behavior, differentiation potential, and gene expression. Although ECs are prone to differentiate into all three germ layers and give rise to the non-seminomatous GCT entities teratoma, choriocarcinoma, and yolk-sac tumor, differentiation of seminomas to these entities is only rarely observed. This might reflect the ability of seminomas to actively inhibit differentiation processes evoked by environmental cues. Also, it is not known why CIS gives rise to seminoma in some patients and to non-seminoma in the others. Here, we treated the seminoma-like cell line TCam-2 with the HDAC-inhibitor Depsipeptide, the global demethylating agent 5-aza-2'-deocycytidine, all-trans retinoic acid and the monaminooxidase inhibitor Tranylcipromine and also used knock down approaches to reduce expression of the pluripotency marker NANOG and/or the inhibitor of primordial germ cell differentiation TFAP2C. We found that TCam-2 cells induce apoptosis when treated with Depsipeptide (> 10 nM) but are resistant to treatments with 5-aza-2'-deocycytidine, all-trans retinoic acid and Tranylcipromine, highlighting Depsi as a treatment option for seminomas. We show that TCam-2 cells up-regulate endoderm- and throphectoderm-associated genes after down-regulation of NANOG expression; however, morphologically no indications of differentiation could be found. Instead, we observed up-regulation of OCT3/4 and SOX17 in TCam-2-NANOG knockdown and speculate that this compensates for the loss of the NANOG protein. Hence, NANOG is not a primary target gene responsible for the inhibition of differentiation in seminomas.

Seminoma and Embryonal Carcinoma Footprints Identified by Analysis of Integrated Genome-Wide Epigenetic and Expression Profiles of Germ Cell Cancer Cell Lines

“…SOX2 was partly methylated in TCam-2, in line with findings illustrating that TCam-2 can differentiate and become SOX2 positive after extra-gonadal injection in mice [54]. A 220 bp region directly upstream of the TSS of SOX2 (chr3:181429712) has previously been shown to be completely hypomethylated in TCam-2 [55]. This is in line with our findings as a consistently hypomethylated region (chr3:181429233-181430485) is shown directly upstream of the TSS while a 652 bp long DMR (chr3:181428046-181428697) between NCCIT and TCam-2 is detected by DMRforPairs in a region ca.…”

Valproic Acid Confers Functional Pluripotency to Human Amniotic Fluid Stem Cells in a Transgene-free Approach

“…These data are indicative of allelic differential methylation at the H19 DMD, as expected from the monoallelic expression of H19 in AFSC. We next compared the whole genome transcriptome identity of AFSC_VPA with the seminoma cell line TCam-2, 32 which exhibit characteristics of fetal germ cell ( Supplementary Figure S5 ). Results showed that AFSC and TCam-2 cells share 39% transcriptome identity ( Figure 8f ).…”

Transcription Factor TFAP2C Regulates Major Programs Required for Murine Fetal Germ Cell Maintenance and Haploinsufficiency Predisposes to Teratomas in Male Mice

“…siRNA mediated knockdown of TFAP2C in TCam-2 cells was performed as described by [27]. Scrambled and TFAP2C siRNA were obtained from Origene (TFAP2C SR304789, Origene Technologies, Rockville, USA).…”