The New Tumour Biomarker <i>miRNA‐371‐3p</i> Influences Cisplatin Sensitivity of Testicular Germ Cell Tumour Cell Lines

Cisplatin is used to treat a variety of malignancies, including testicular germ cell tumours (TGCTs). Although cisplatin-based chemotherapy yields high response rates, a subset of patients develop cisplatin resistance, limiting treatment options and worsening prognosis. Therefore, there is a high clinical need for new therapeutic strategies targeting cisplatin-resistant TGCTs. MicroRNA-371a-3p (miR-371), the new serum biomarker for TGCTs, shows significantly increased expression in cisplatin-resistant TGCT cell lines compared to sensitive parental cell lines. However, the functional impact of miR-371 on cisplatin sensitivity has not been investigated yet. To evaluate the impact of miR-371 on cisplatin sensitivity, antagomirs were used to inhibit miR-371 expression, resulting in a > 98% decrease in miR-371 expression. Cisplatin sensitivity was significantly increased after miR-371 inhibition in cisplatin-resistant and corresponding parental TGCT cell lines, indicating a strongly reduced viability and increased apoptosis after cisplatin treatment in miR-371-inhibited cells. Our results suggest that miR-371 may contribute to the development of cisplatin resistance in TGCTs. Interfering with miR-371 expression can increase the cisplatin sensitivity of tumour cells, which may represent a promising approach to improve future therapeutic outcomes in patients with TGCTs, especially those with cisplatin-resistant disease.