17β-Estradiol activates GPER- and ESR1-dependent pathways inducing apoptosis in GC-2 cells, a mouse spermatocyte-derived cell line.
In mammals, spontaneous apoptosis is observed particularly in differentiating spermatogonia and in spermatocytes. 17β-Estradiol (E2) in primary rat pachytene spermatocytes (PS) binds estrogen receptor α (ESR1) and GPER to activate EGFR/ERK/c-Jun pathway leading to up regulation of proapoptotic factor bax. Aim of this study was to clarify the effector pathway(s) controlling spermatocytes apoptosis using as model GC-2 cells, an immortalized mouse pachytene spermatocyte-derived cell line, which reproduces primary cells responses to E2. In fact, in GC-2 cells we observed that ESR1 and GPER activation caused rapid ERK and c-Jun phosphorylation, bax up-regulation, events associated with apoptosis. We further investigated the apoptotic mechanism demonstrating that E2, as well as ESR1 and GPER specific agonists, induced sustained ERK, c-Jun and p38 phosphorylation, Cytochrome c release, caspase 3 and endogenous substrate Poly (ADP-ribose) polymerase (PARP) activation and increased expression of cell cycle inhibitor p21. When ESR1 or GPER expression was silenced, E2 was still able to decrease cell proliferation, only the concomitant silencing abolished E2 effect. These results indicate that GC-2 cells are a valid cell model to study E2-dependent apoptosis in spermatocytes and show that E2, activating both ESR1 and GPER, is able to induce an ERK1/2, c-Jun and p38-dependent mitochondrion apoptotic pathway in this cell type.
Department of Pharmaco-Biology, University of Calabria, 87036 Arcavacata di Rende, Cosenza, Italy.
Adele
A
Chimento
Rosa
R
Sirianni
Ivan
I
Casaburi
Carmen
C
Ruggiero
Marcello
M
Maggiolini
Sebastiano
S
Andò
Vincenzo
V
Pezzi
D000818:Animals; D017209:Apoptosis / Q000187:drug effects*; D053148:Caspase 3 / Q000235:genetics / Q000378:metabolism; D002460:Cell Line; D045304:Cytochromes c / Q000378:metabolism; D004958:Estradiol / Q000494:pharmacology*; D047628:Estrogen Receptor alpha / Q000235:genetics / Q000378:metabolism; D048049:Extracellular Signal-Regulated MAP Kinases / Q000235:genetics / Q000378:metabolism; D005786:Gene Expression Regulation / Q000187:drug effects*; D048031:JNK Mitogen-Activated Protein Kinases / Q000235:genetics / Q000378:metabolism; D008297:Male; D051379:Mice; D010766:Phosphorylation / Q000187:drug effects; D011065:Poly(ADP-ribose) Polymerases / Q000235:genetics / Q000378:metabolism; D043562:Receptors, G-Protein-Coupled / Q000235:genetics / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects / Q000235:genetics*; D013090:Spermatocytes / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D051028:bcl-2-Associated X Protein / Q000235:genetics / Q000378:metabolism; D054462:p21-Activated Kinases / Q000235:genetics / Q000378:metabolism; D048051:p38 Mitogen-Activated Protein Kinases / Q000235:genetics / Q000378:metabolism
D047628:Estrogen Receptor alpha; D043562:Receptors, G-Protein-Coupled; D051028:bcl-2-Associated X Protein; D004958:Estradiol; D045304:Cytochromes c; D011065:Poly(ADP-ribose) Polymerases; D054462:p21-Activated Kinases; D048049:Extracellular Signal-Regulated MAP Kinases; D048031:JNK Mitogen-Activated Protein Kinases; D048051:p38 Mitogen-Activated Protein Kinases; D053148:Caspase 3