High expression of somatostatin receptors and messenger ribonucleic acid for its receptor subtypes in organ-confined and locally advanced human prostate cancers.

Published

Journal Article

To evaluate the potential application of somatostatin (SST) analogs as an adjuvant treatment for prostate cancer, we characterized the binding sites for SST octapeptide analogs on prostate cancers in patients treated with radical prostatectomy. The affinity and density of binding sites for SST analog RC-160 on 80 surgical specimens of prostate cancers were determined by ligand competition assays. The expression of messenger ribonucleic acid (mRNA) for SST receptor subtype 1 (SSTR1), subtype 2 (SSTR2), and subtype 5 (SSTR5) was also investigated in 22 samples by RT-PCR. Fifty-two of 80 specimens (65%), showed a single class of specific binding sites for RC-160 with a mean dissociation constant (K(d)) of 9.44 nmol/L and a mean maximal binding capacity of 754.8 fmol/mg membrane protein. The mRNA for SSTR1 was detected in 86% of samples, whereas the incidences of mRNA for SSTR2 and SSTR5 were 14% and 64%, respectively. The expression of SSTR2 and/or SSTR5 was 100%, consistent with the presence of RC-160 binding. In patients at high risk of cancer recurrence (stage pT3 and/or Gleason score of 8-10), the incidence of RC-160 binding (65.7%) was similar to that observed in the low risk group (64.3%). The demonstration of the high incidence of octapeptide-preferring SSTRs in organ-confined and locally advanced prostate cancers supports the merit of further investigations of the application of SST analogs and their radionuclide and cytotoxic derivatives for adjuvant treatment of patients at high risk of cancer recurrence after radical prostatectomy. Such approaches could be also considered for patients with advanced prostate cancer at the time of relapse.

Full Text

Duke Authors

Cited Authors

  • Halmos, G; Schally, AV; Sun, B; Davis, R; Bostwick, DG; Plonowski, A

Published Date

  • July 2000

Published In

Volume / Issue

  • 85 / 7

Start / End Page

  • 2564 - 2571

PubMed ID

  • 10902809

Pubmed Central ID

  • 10902809

International Standard Serial Number (ISSN)

  • 0021-972X

Digital Object Identifier (DOI)

  • 10.1210/jcem.85.7.6698

Language

  • eng

Conference Location

  • United States