Germ cell tumors (GCTs) constitute diverse neoplasms arising in the gonads or extragonadal locations. Testicular GCTs (TGCTs) are the predominant solid tumors in adolescents and young men. Despite cisplatin serving as the primary therapeutic intervention for TGCTs, 10–20% of patients with advanced disease demonstrate resistance to cisplatin-based chemotherapy, and epithelial-mesenchymal transition (EMT) is a potential contributor to this resistance. EMT is regulated by various factors, including the snail family transcriptional repressor 2 (
SLUG
) transcriptional factor, and, to the best of our knowledge, remains unexplored within TGCTs. Therefore, the present study investigated the EMT transcription factor
SLUG
in TGCTs.
In silico
analyses were performed to investigate the expression of EMT markers in TGCTs. In addition, a cisplatin-resistant model for TGCTs was developed using the NTERA-2 cell line, and a mouse model was also established. Subsequently, EMT was assessed both
in vitro
and
in vivo
within the cisplatin-resistant models using quantitative PCR and western blot analyses. The results of the
in silico
analysis showed that the different histologies exhibited distinct expression profiles for EMT markers. Seminomas exhibited a lower expression of EMT markers, whereas embryonal carcinomas and mixed GCT demonstrated high expression. Notably, patients with lower
SLUG
expression had longer median progression-free survival (46.4 months vs. 28.0 months, P=0.022). In the
in vitro
analysis, EMT-associated genes [fibronectin; vimentin (
VIM
); actin, α2, smooth muscle; collagen type I α1; transforming growth factor-β1; and
SLUG
] were upregulated in the cisplatin-resistant NTERA-2 (NTERA-2R) cell line after 72 h of cisplatin treatment. Consistent with this finding, the NTERA-2R mouse model demonstrated a significant upregulation in the expression levels of
VIM
and
SLUG.
In conclusion, the present findings suggested that
SLUG
may serve a crucial role in connecting EMT with the development of cisplatin resistance, and targeting
SLUG
may be a putative therapeutic strategy to mitigate cisplatin resistance.