Evidence has accumulated indicating that LHRH might behave as an autocrine/paracrine growth inhibitory factor in some peripheral tumors. However, LHRH receptors in tumor cells have not been fully characterized, so far. The present experiments were performed to analyze: 1) the messenger RNA expression; 2) the molecular size; and 3) the signal transduction pathway of LHRH receptors in prostate cancer. For these studies, the human androgen-dependent LNCaP and androgen-independent DU 145 prostate cancer cell lines were used. 1) By RT-PCR, a complementary DNA product, which hybridized with a 32P-labeled oligonucleotide probe specific for the pituitary LHRH receptor complementary DNA, was found both in LNCaP and in DU 145 cells. 2) Western blot analysis, using a monoclonal antibody raised against the human pituitary LHRH receptor, revealed the presence of a protein band of approximately 64 kDa (corresponding to the molecular mass of the pituitary receptor) in both cell lines. 3) In LNCaP and DU 145 cells, pertussis toxin completely abrogated the antiproliferative action of a LHRH agonist (LHRH-A). Moreover, LHRH-A substantially antagonized the pertussis toxin-catalyzed ADP-ribosylation of a Galpha(i) protein. Finally, LHRH-A significantly counteracted the forskolin-induced increase of intracellular cAMP levels in both cell lines. These data demonstrate that the LHRH receptor, which is present in prostate cancer cells, independently of whether they are androgen-dependent or not, corresponds to the pituitary receptor, in terms of messenger RNA expression and protein molecular size. However, at variance with the receptor of the gonadotrophs, prostate cancer LHRH receptor seems to be coupled to the Galpha(i) protein-cAMP signal transduction pathway, rather than to the Galpha(q/11)-phospholipase C signaling system. This might be responsible for the different actions of LHRH in anterior pituitary and in prostate cancer.

The luteinizing hormone-releasing hormone receptor in human prostate cancer cells: messenger ribonucleic acid expression, molecular size, and signal transduction pathway / P. Limonta, R.M. Moretti, M. Montagnani Marelli, D. Dondi, M. Parenti, M. Motta. - In: ENDOCRINOLOGY. - ISSN 0013-7227. - 140:11(1999 Nov), pp. 5250-5256.

The luteinizing hormone-releasing hormone receptor in human prostate cancer cells: messenger ribonucleic acid expression, molecular size, and signal transduction pathway

P. Limonta
Primo
;
R.M. Moretti
Secondo
;
M. Montagnani Marelli;D. Dondi;M. Motta
Ultimo
1999-11

Abstract

Evidence has accumulated indicating that LHRH might behave as an autocrine/paracrine growth inhibitory factor in some peripheral tumors. However, LHRH receptors in tumor cells have not been fully characterized, so far. The present experiments were performed to analyze: 1) the messenger RNA expression; 2) the molecular size; and 3) the signal transduction pathway of LHRH receptors in prostate cancer. For these studies, the human androgen-dependent LNCaP and androgen-independent DU 145 prostate cancer cell lines were used. 1) By RT-PCR, a complementary DNA product, which hybridized with a 32P-labeled oligonucleotide probe specific for the pituitary LHRH receptor complementary DNA, was found both in LNCaP and in DU 145 cells. 2) Western blot analysis, using a monoclonal antibody raised against the human pituitary LHRH receptor, revealed the presence of a protein band of approximately 64 kDa (corresponding to the molecular mass of the pituitary receptor) in both cell lines. 3) In LNCaP and DU 145 cells, pertussis toxin completely abrogated the antiproliferative action of a LHRH agonist (LHRH-A). Moreover, LHRH-A substantially antagonized the pertussis toxin-catalyzed ADP-ribosylation of a Galpha(i) protein. Finally, LHRH-A significantly counteracted the forskolin-induced increase of intracellular cAMP levels in both cell lines. These data demonstrate that the LHRH receptor, which is present in prostate cancer cells, independently of whether they are androgen-dependent or not, corresponds to the pituitary receptor, in terms of messenger RNA expression and protein molecular size. However, at variance with the receptor of the gonadotrophs, prostate cancer LHRH receptor seems to be coupled to the Galpha(i) protein-cAMP signal transduction pathway, rather than to the Galpha(q/11)-phospholipase C signaling system. This might be responsible for the different actions of LHRH in anterior pituitary and in prostate cancer.
Animals ; Pituitary Gland ; GTP-Binding Protein alpha Subunits, Gi-Go ; Humans ; Cyclic AMP ; Gene Expression ; Goserelin ; Molecular Weight ; Rats; RNA, Messenger ; Rats, Sprague-Dawley ; Blotting, Western ; Pertussis Toxin ; Tumor Cells, Cultured ; Virulence Factors, Bordetella ; Type C Phospholipases ; Prostatic Neoplasms ; Receptors, LHRH ; Signal Transduction ; Adenosine Diphosphate Ribose ; Male
Settore BIO/13 - Biologia Applicata
Settore BIO/09 - Fisiologia
Article (author)
File in questo prodotto:
File Dimensione Formato  
5250.full.pdf

accesso aperto

Tipologia: Publisher's version/PDF
Dimensione 3.11 MB
Formato Adobe PDF
3.11 MB Adobe PDF Visualizza/Apri
Pubblicazioni consigliate

Caricamento pubblicazioni consigliate

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: http://hdl.handle.net/2434/170156
Citazioni
  • ???jsp.display-item.citation.pmc??? 22
  • Scopus 122
  • ???jsp.display-item.citation.isi??? 123
social impact