Luteinizing hormone and GATA4 action in the adrenocortical tumorigenesis of gonadectomized female mice

Abstract

<p><strong><em>Background/Aims:</em></strong> Physiological role of luteinizing hormone (LH) and its receptor (LHCGR) in adrenal remains unknown. In inhibin-α/Simian Virus 40 T antigen (SV40Tag) (inhα/Tag) mice, gonadectomy-induced (OVX) elevated LH triggers the growth of transcription factor GATA4 (GATA4)-positive adrenocortical tumors in a hyperplasia-adenoma-adenocarcinoma sequence. </p><p><b><i>Methods:</i></b> We investigated the role of LHCGR in tumor induction, by crossbreeding inhα/Tag with <i>Lhcgr</i> knockout (LuRKO) mice. By knocking out <i>Lhcgr</i> and <i>Gata4</i> in Cα1 adrenocortical cells (<i>Lhcgr-ko, Gata4</i>-ko) we tested their role in tumor progression. <b><i></i></b></p><p><b><i>Results:</i></b> Adrenal tumors of OVX inhα/Tag mice develop from the hyperplastic cells localized in the topmost layer of zona fasciculata. OVX inhα/Tag/LuRKO only developed SV40Tag positive hyperplastic cells that were GATA4 negative, cleaved caspase-3 positive and did not progress into adenoma. In contrast to <i>Lhcgr-ko, Gata4</i>-ko Cα1 cells presented decreased proliferation, increased apoptosis, decreased expression of <i>Inha</i>, <i>SV40Tag</i> and <i>Lhcgr</i> tumor markers, as well as up-regulated adrenal- and down-regulated sex steroid gene expression. Both <i>Gata4</i>-ko and <i>Lhcgr</i>-ko Cα1 cells had decreased expression of steroidogenic genes resulting in decreased basal progesterone production. <b><i></i></b></p><p><b><i>Conclusion:</i></b> Our data indicate that LH/LHCGR signaling is critical for the adrenal cell reprogramming by GATA4 induction prompting adenoma formation and gonadal-like phenotype of the adrenocortical tumors in inhα/Tag mice.<br /></p>