Quantitation of somatostatin receptor type 2 gene expression in neuroblastoma cell lines and primary tumors using competitive reverse transcription-polymerase chain reaction
Abstract
We previously reported the presence of somatostatin (SS-14)-binding sites in a wide panel of human neuroblastoma (NB) tumor cell lines. Given that the adrenal gland and its relative embryonal and adult tumors express an abundance of mRNA for somatostatin receptor type 2 (sst2) mRNA, we studied the quantitative expression of sst2 in 6 NB cell lines and 15 primary tumors using competitive reverse transcription (RT)-PCR.
This method uses an insertion mutant of the target gene as a competitor for the RT-PCR reaction, thus allowing exact quantitation of sst2 mRNA abundance. We found expression of specific transcripts for sst2 in all of the NB cell lines and tumors investigated (range, 9 x 10(5)-4 x 10(9) molecules/microg RNA).
In NB cells, the expression of sst2 was highly correlated with SS-14-binding sites (R = 0.93). In primary tumors, sst2 was positively related to the expression of the neuroendocrine marker secretogranin II (P < 0.05) and negatively related to N-myc amplification (a poor prognostic factor, P < 0.005) and metastatic dissemination (P < 0.05).
In addition, Kaplan-Meier curves indicate that sst2 expression is positively related to survival (P = 0.01). In a patient with stage IVs disease (a spontaneously regressing form), we found the highest sst2 expression (4 x 10(9) molecules/microgram RNA), a value relatively similar to that of normal adrenal.
In conclusion, these data indicate that quantitation of sst2, as assessed with competitive RT-PCR, could represent a new prognostic tool in the neuroendocrine tumor NB. Since sst2 recognizes octreotide with high affinity, these findings could also have both diagnostic and therapeutic value.
See also:
- Official Web Site: The Di Bella Method;
- 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, 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);
- The Di Bella Method (A Fixed Part - Calcium, 2 grams per day, orally);
- Neuroblastoma: Complete objective response to biological treatment;
- 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;
- Pancreatic Adenocarcinoma: clinical records on 17 patients treated with Di Bella's Method;
- Complete objective response to biological therapy of plurifocal breast carcinoma;