ISSN 1470-3947 (print) | ISSN 1479-6848 (online)

Endocrine Abstracts (2019) 63 P709 | DOI: 10.1530/endoabs.63.P709

Protein expression of convertases involved in POMC processing in silent and functioning corticotroph tumors

David Cano1, Araceli García-Martínez2, Álvaro Flores1, Joan Gil3, Manel Puig-Domingo3, Susan M Webb4, Alfonso Soto1 & Antonio Picó5


1Endocrinology Department, Hospital Universitario del Rocío, Sevilla, Grupo Vinculado CIBERER 15, Sevilla, Spain; 2Research Laboratory, Hospital General Universitario de Alicante, ISABIAL, Grupo Vinculado CIBERER 13, Alicante, Spain; 3Endocrinology Department, IGTP, Badalona, Grupo Vinculado CIBERER 14, Badalona, Spain; 4Endocrinology Department, Hospital Sant-Pau, Barcelona, Grupo U747 CIBERER, Barcelona, Spain; 5Endocrinology Department, Hospital General Universitario de Alicante, ISABIAL, Grupo Vinculado CIBERER 13, Alicante, Spain.


Introduction: Previous results of our group, presented in the ECE last year, showed a lower gene expression of proconvertase PC1/3, involved in the processing of POMC, in silent corticotroph tumors (sCT) than in functioning ones (fCT), overall and in microadenomas. The aim of the present study was to quantify the protein expression of convertases involved in the processing of POMC (PC1/3) and in the degradation of ACTH (PC2, CPE and PAM) in a series of CT.

Methods: We selected 15 sCT, 15 fCT and 14 silent gonadotroph tumors (sGT) (control group). Previously, the gene expression of these convertases was quantified by quantitative PCR. The quantification of protein expression was carried out by Western Blot.

Results: Similar to gene expression studies, sCT showed lower PC1/3 protein expression than fCT (P=0.078), especially than fCT microadenomas (P=0.028). Moreover, we observed a strong positive correlation between PC2 and CPE gene and protein expression (ρ≥0.670, P<0.009) in sCT but a lack of correlation in the case of PC1/3.

Conclusion: The difference in PC1/3 expression between sCT and fCT remains at the proteins level. This low gene and protein PC1/3 expressions and the efficient post-transcriptional processing of PC2 and CPE in sCT compared with fCT could explain the lack of Cushing symptomatology in sCT. Moreover, we confirmed that the macro CT represent an intermediate state between silent and micro fCT.

Grant from the CIBERER (Rare Disease Network of Excellence) ER15TRL2EOI9/2017.

Article tools

My recent searches

No recent searches.