Teratocarcinoma-derived growth factor-1 is upregulated in aldosterone-producing adenomas and increases aldosterone secretion and inhibits apoptosis in vitro.
Aldosterone-producing adenomas (APA) are a frequent cause of secondary hypertension characterized by autonomous hypersecretion of aldosterone. However, the molecular mechanisms involved in adrenal tumorigenesis and deregulated aldosterone secretion are currently unknown. To identify putative functional genes, a transcriptional screening was performed on 8 APA and 3 normal adrenals (NA) using oligonucleotide microarrays. Data were next validated on an expanded set of samples by real-time PCR (APA, n=19; NA, n=10). The epidermal growth factor-like teratocarcinoma-derived growth factor-1 (TDGF-1) was upregulated in APA compared with NA (14.7-fold and 21.4-fold by microarray and real-time PCR, respectively). In vitro studies and Western blot analysis using the NCI H295R adrenocortical cell line showed that TDGF-1 increased Akt phosphorylation on Thr308 and Ser473, consistent with activation of phosphatidylinositol 3-kinase/Akt signaling, and also demonstrated a concomitant inactivation of the Akt substrate glycogen synthesis kinase-3beta via Ser9 phosphorylation. Furthermore, TDGF-1 mediated a 3.8+/-0.4-fold increase in aldosterone secretion (n=4) that was specifically blocked by the phosphatidylinositol 3-kinase inhibitors wortmannin (50 nmol/L) and LY294002 (20 micromol/L). Finally, TDGF-1 protected H295R cells from apoptosis induced by staurosporine, causing a decrease in caspase-3 activity, a reduction in the inactivation of poly(ADP-ribose) polymerase, and an inhibition of DNA fragmentation, detected by the TUNEL reaction and fluorescence microscopy that was blocked by LY294002. Taken together, our data suggest that TDGF-1, which is significantly upregulated in APA and mediates aldosterone hypersecretion and deregulated growth in adrenocortical cells in vitro, may represent a key player in the development and pathophysiology of primary aldosteronism.
Williams
Tracy A
TA
Department of Medicine and Experimental Oncology, University of Torino, Torino, Italy. tracyann.williams@unito.it
Monticone
Silvia
S
Morello
Fulvio
F
Liew
Choong-Chin
CC
Mengozzi
Giulio
G
Pilon
Catia
C
Asioli
Sofia
S
Sapino
Anna
A
Veglio
Franco
F
Mulatero
Paolo
P
D000236:Adenoma / Q000378:metabolism* / Q000601:surgery; D000306:Adrenal Cortex Neoplasms / Q000378:metabolism* / Q000601:surgery; D000315:Adrenalectomy; D000328:Adult; D000368:Aged; D000450:Aldosterone / Q000378:metabolism*; D017209:Apoptosis / Q000502:physiology*; D014408:Biomarkers, Tumor / Q000378:metabolism*; D001707:Biopsy, Needle; D015153:Blotting, Western; D053148:Caspase 3 / Q000378:metabolism*; D049109:Cell Proliferation; D004815:Epidermal Growth Factor / Q000378:metabolism*; D005260:Female; D058851:GPI-Linked Proteins; D006801:Humans; D007150:Immunohistochemistry; D020287:In Situ Nick-End Labeling; D036341:Intercellular Signaling Peptides and Proteins; D008297:Male; D008562:Membrane Glycoproteins / Q000378:metabolism*; D008875:Middle Aged; D009363:Neoplasm Proteins / Q000378:metabolism*; D020411:Oligonucleotide Array Sequence Analysis; D012334:RNA, Neoplasm / Q000032:analysis; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015398:Signal Transduction; D046509:Tissue Culture Techniques; D014407:Tumor Cells, Cultured; D015854:Up-Regulation
D014408:Biomarkers, Tumor; D058851:GPI-Linked Proteins; D036341:Intercellular Signaling Peptides and Proteins; D008562:Membrane Glycoproteins; D009363:Neoplasm Proteins; D012334:RNA, Neoplasm; C070636:TDGF1 protein, human; D000450:Aldosterone; D004815:Epidermal Growth Factor; D053148:Caspase 3