Peptide Radioligands in Cancer Theranostics: Agonists and Antagonists

Abstract

The clinical success of radiolabeled somatostatin analogs in the diagnosis and therapy-"theranostics"-of tumors expressing the somatostatin subtype 2 receptor (SST2R) has paved the way for the development of a broader panel of peptide radioligands targeting different human tumors.

This approach relies on the overexpression of other receptor-targets in different cancer types. In recent years, a shift in paradigm from internalizing agonists to antagonists has occurred.

Thus, SST2R-antagonist radioligands were first shown to accumulate more efficiently in tumor lesions and clear faster from the background in animal models and patients.

The switch to receptor antagonists was soon adopted in the field of radiolabeled bombesin (BBN).

Unlike the stable cyclic octapeptides used in the case of somatostatin, BBN-like peptides are linear, fast to biodegradable and elicit adverse effects in the body. Thus, the advent of BBN-like antagonists provided an elegant way to obtain effective and safe radiotheranostics.

Likewise, the pursuit of gastrin and exendin antagonist-based radioligands is advancing with exciting new outcomes on the horizon.

In the present review, we discuss these developments with a focus on clinical results, commenting on challenges and opportunities for personalized treatment of cancer patients by means of state-of-the-art antagonist-based radiopharmaceuticals.

About this publication.

See also:

- Official Web Site: The Di Bella Method;

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

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

- Publication, 2018 Jul: Over-Expression of GH/GHR in Breast Cancer and Oncosuppressor Role of Somatostatin as a Physiological Inhibitor (from Di Bella's Foundation);

- Publication, 2018 Sep: The over-expression of GH/GHR in tumour tissues with respect to healthy ones confirms its oncogenic role and the consequent oncosuppressor role of its physiological inhibitor, somatostatin: a review of the literature (from Di Bella's Foundation);

- Publication, 2019 Aug: The Entrapment of Somatostatin in a Lipid Formulation: Retarded Release and Free Radical Reactivity (from Di Bella's Foundation);

- Publication, 2019 Sep: Effects of Somatostatin and Vitamin C on the Fatty Acid Profile of Breast Cancer Cell Membranes (from Di Bella's Foundation);

- Publication, 2019 Sep: Effects of somatostatin, curcumin, and quercetin on the fatty acid profile of breast cancer cell membranes (from Di Bella's Foundation);

- Publication, 2020 Sep: Two neuroendocrine G protein-coupled receptor molecules, somatostatin and melatonin: Physiology of signal transduction and therapeutic perspectives (from Di Bella's Foundation);

- The Di Bella Method (A Fixed Part - Bromocriptine and/or Cabergoline);

- Prolactin inhibitors in oncology - In vitro, review and in vivo publications;

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

- The Di Bella Method (A Fixed Part - Calcium, 2 grams per day, orally);

- Pancreatic Adenocarcinoma: clinical records on 17 patients treated with Di Bella's Method;

- The Di Bella Method Increases by the 30% the survival rate for Pancreas tumors and for this reason should be proposed as first line therapy for this type of cancer;

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

- A retrospective observational study on cases of Osteosarcomas treated with a multitherapy: The rationale and effectiveness;

- A Retrospective Observational Study on Cases of Sarcoma Treated with the Di Bella Method: Rationale and Effectiveness;

- Congenital fibrosarcoma in complete remission with Somatostatin, Retinoids, Vitamin D3, Vitamin E, Vitamin C, Melatonin, Calcium, Chondroitin sulfate associated with low doses of Cyclophosphamide in a 14-year Follow Up;

- 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;

- A retrospective observational study on cases of anaplastic brain tumors treated with the Di Bella Method: A rationale and effectiveness;

- Recurrent Glioblastoma Multiforme (grade IV – WHO 2007): a case of complete objective response achieved by means of the concomitant administration of Somatostatin and Octreotide – Retinoids – Vitamin E – Vitamin D3 – Vitamin C – Melatonin – D2 R agonists (Di Bella Method – DBM) associated with Temozolomide;

- The Di Bella Method DBM improved survival objective response and performance status in a retrospective observational clinical study on 23 tumours of the head and neck;

- 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;

- Pleural Mesothelioma: clinical records on 11 patients treated with Di Bella's Method;

- Malignant pleural mesothelioma, stage T3-T4. Consideration of a case study;

- Excellent result in a Mesothelioma case treated exclusively with Di Bella Method for over 4 years and still treatment with positive results;

- A case of advanced Multiple Myeloma treated with Di Bella Method (DBM) into total remission for 13 years;

- Neuroblastoma: Complete objective response to biological treatment;

- Cyclophosphamide plus Somatostatin, Bromocriptin, Retinoids, Melatonin and ACTH in the Treatment of Low-grade Non-Hodgkin’s Lymphomas at Advanced Stage: Results of a Phase II Trial;

- Relapse of High-Grade Non-Hodgkin’s Lymphoma After Autologous Stem Cell Transplantation: A Case Successfully Treated With Cyclophosphamide Plus Somatostatin, Bromocriptine, Melatonin, Retinoids, and ACTH;

- Low-grade Non-Hodgkin Lymphoma at Advanced Stage: A Case Successfully Treated With Cyclophosphamide Plus Somatostatin, Bromocriptine, Retinoids, and Melatonin;

- The Di Bella Method (DBM) improved survival, objective response and performance status in a retrospective observational clinical study on 55 cases of Lymphomas;

- Large B-cells Non-Hodgkin's Lymphoma, Stage IV-AE: a Case Report;

- Non-Hodgkin's Lymphoma, Stage III-B-E: a Case Report;

- Oesophageal squamocellular carcinoma: a complete and objective response.