Detection of somatostatin receptor subtype 2 (SSTR2) in established tumors and tumor cell lines: evidence for SSTR2 heterogeneity.

Abstract

The somatostatin receptor subtype 2 (SSTR2) was detected in a wide range of human and rat tumors using in vitro receptor binding ([125I]MK-678), receptor gene expression analysis, and immunoblotting techniques. The highest receptor concentrations were observed in the rat AR42J pancreatic and human small cell lung cancer (SCLC) cell lines, NCI-H69 and NCI-H345, with much lower levels detected in breast, prostate, melanoma, and hepatic tumors. Several human pancreas tumors were devoid of SSTR2. For all tumors showing detectable [125I]MK-678 binding, SSTR2 receptor mRNA was expressed. Furthermore, a mRNA transcript corresponding to a truncated isoform of SSTR2 was detected at low levels in the human SCLC NCI-H69 cell line, and likely represents a human homologue of rodent SSTR2B. Immunoblotting analysis using the SSTR2-specific antibody, 2e3, detected multiple immunoreactive protein species, including a predominant 150-kDa molecule, which could be blocked by the SSTR2-derived 2e3 peptide. Somatostatin (SRIF) peptides with high SSTR2 affinity and antiproliferative properties were potent inhibitors of [125I]MK-678 binding to several tumor types, suggesting that they may exert antitumor effects via the SSTR2 receptor.

• Authors: J E Taylor, M A Theveniau, R Bashirzadeh, T Reisine, P A Eden
• Journal: Peptides (Peptides) Vol. 15 Issue 7 Pg. 1229-36 ( 1994) ISSN: 0196-9781 [Print] United States
• PMID: 7854974 (Publication Type: Journal Article)

Chemical References

• DNA Primers
• DNA, Neoplasm
• RNA, Messenger
• Receptors, Somatostatin

Topics

• Animals
• Base Sequence
• Breast Neoplasms (genetics, metabolism)
• DNA Primers (genetics)
• DNA, Neoplasm (genetics)
• Female
• Gastrointestinal Neoplasms (genetics, metabolism)
• Gene Expression
• Humans
• In Vitro Techniques
• Kinetics
• Lung Neoplasms (genetics, metabolism)
• Male
• Melanoma (genetics, metabolism)
• Mice
• Molecular Sequence Data
• Neoplasms (genetics, metabolism)
• Polymerase Chain Reaction
• Prostatic Neoplasms (genetics, metabolism)
• RNA, Messenger (genetics, metabolism)
• Rats
• Receptors, Somatostatin (classification, genetics, metabolism)
• Tumor Cells, Cultured (metabolism)