Endocrine Abstracts

It is well established that oestrogens participate in the control of normal spermatogenesis and endogenous or environmental oestrogens are involved in pathological germ cell proliferation including testicular germ cell tumours. The effects of oestrogen are now known to be mediated by oestrogen receptor-α (ERα) and ERβ subtypes, but only ERβ has been found in human germ cells of normal testis. However, its expression was markedly diminished in seminomas, embryonal cell carcinomas, and in mixed germ cell tumours but remains high in teratomas.

The interaction and the expression of ERβ and HMGA1 were studied by using 32 cases of cryopreserved seminomas and the GC1 and TCam-2 germ cell lines.

Here, we shown that ERβ interacts with HMGA1 in normal germ cells, while down regulation of ERβ associates with transcriptional coregulator HMGA1 over-expression and cytoplasmic localization in human testicular seminomas. In addition, we show that 17β-oestradiol induces an HMGA1 increased cytoplasmic expression associated to an ERβ down-regulation in TCam-2 cell line derived from human testicular seminoma.

Taken togheter, our results suggest to hypothesize that exposure to oestrogens or oestrogen-mimics, in some as of yet undefined manner, diminishes the ERβ-mediated growth restraint in human testicular seminoma, due to the HMGA1 cytoplasmic delocalization associated with ERβ down-regulation.

Declaration of interest: The authors declare that there is no conflict of interest that could be perceived as prejudicing the impartiality of the research project.

Funding: This research did not receive any specific grant from any funding agency in the public, commercial or not-for-profit sector.