Long non-coding RNA H19 promotes TDRG1 expression and cisplatin resistance by sequestering miRNA-106b-5p in seminoma

The role of TDRG1 in tumorigenesis and the progression of seminoma, as well as its role in regulating chemosensitivity of seminoma to cisplatin through the PI3K/Akt/mTOR signaling pathway, has been previously defined. However, the detailed mechanism underlying TDRG1 expression and concomitant chemoresistance conditions are unknown. Furthermore, it has been reported that non-protein-coding RNAs play an important role in a variety of vital processes including cellular chemosensitivity. However, the role of non-protein-coding RNAs in regulating the chemosensitivity of seminoma remains unknown. In this study, using microarray analysis, we found that long non-coding RNA H19 was upregulated while miRNA-106b-5p was downregulated in an established cisplatin-resistant TCam-2 cell line. Moreover, H19 acts as a miRNA-106b-5p sponge and thus impairs the function of miRNA-106b-5p on its target gene, TDRG1. Based on these findings, we propose that H19 promotes the expression of TDRG1 by sequestering miRNA-106b-5p and uses this mechanism to facilitate cell survival in cisplatin-based chemotherapeutic conditions. These findings elucidate the mechanisms, at least partially, applied to deregulate TDRG1 and cisplatin sensitivity, and may provide new therapeutic possibilities for chemoresistant seminoma.