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

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Published on Tuesday, 09 April 2019

Abstract

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.

 

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See also:

- Official Web Site: The Di Bella Method;

- Somatostatin in oncology, the overlooked evidences - In vitro, review and in vivo publications;

- The Di Bella Method (A Fixed Part - Somatostatin, Octreotide, Sandostatin LAR, analogues and/or derivatives);

- The Di Bella Method (A Fixed Part - Cyclophosphamide 50mg tablets and/or Hydroxyurea 500mg tablets, one or two per day);

- The Di Bella Method (DBM) in the treatment of prostate cancer: a preliminary retrospective study of 16 patients and a review of the literature;

- The Synergism of Somatostatin, Melatonin, Vitamins Prolactin and Estrogen Inhibitors Increased Survival, Objective Response and Performance Status In 297 Cases of Breast Cancer;

- Complete objective response, stable for 5 years, with the Di Bella Method, of multiple-metastatic carcinoma of the breast;

- Evaluation of the safety and efficacy of the first-line treatment with somatostatin combined with melatonin, retinoids, vitamin D3, and low doses of cyclophosphamide in 20 cases of breast cancer: a preliminary report;

- The Di Bella Method (DBM) improved survival, objective response and performance status in a retrospective observational clinical study on 122 cases of breast cancer;

- Complete objective response to biological therapy of plurifocal breast carcinoma;

- Chronic Lymphocytic Leukemia: Long-Lasting Remission with Combination of Cyclophosphamide, Somatostatin, Bromocriptine, Retinoids, Melatonin, and ACTH;

- Somatostatin, retinoids, melatonin, vitamin D, bromocriptine, and cyclophosphamide in advanced non-small-cell lung cancer patients with low performance status;

- Somatostatin, retinoids, melatonin, vitamin D, bromocriptine, and cyclophosphamide in chemotherapy-pretreated patients with advanced lung adenocarcinoma and low performance status;

- Observations on the Report of a case of pulmonary adenocarcinoma with lymph node, hepatic and osseus metastasis.