Heat shock protein 70 (Hsp70) subtype expression in neuroendocrine tissue and identification of a neuroendocrine tumour-specific Hsp70 truncation.

Abstract

In order to identify neuroendocrine tumour-specific protein expression, we generated monoclonal antibodies (mAbs) with a tumour-related reaction pattern using a human insulinoma as immunogen. One of the generated mAbs (mAb 1D4) exhibited striking immunoreactivity against various neuroendocrine tumours without staining pancreatic islets of Langerhans. Furthermore, mAb 1D4 immunostained a characteristic subtype of hypothalamic neurones. Using two-dimensional (2-D) gel electrophoresis, mAb 1D4 immunoblotting and mass spectrometry, heat shock protein 70 (Hsp70) isoforms were identified as the mAb 1D4-specific antigen. In hypothalamic tissue, the presence of two different Hsp70 isoforms (Hsp70-8 and Hsp70-1) was revealed by 2-D gel immunoblots and consecutive mass spectrometric peptide analysis. In contrast, insulinoma and other neuroendocrine tumours displayed solely Hsp70-8 expression. Moreover, the tumour-specific presence of an additional mAb 1D4 immunoreactive protein of 40 kDa was observed in eight out of eight tested neuroendocrine tumours. For this variant, exclusively, peptides derived from the C terminus excluding the 299 amino-terminal residues were detected. In cultured tumour-derived fibroblasts, expression of the truncated Hsp70-8 subtype was not present. In conclusion, we have demonstrated a neuroendocrine tumour-specific expression pattern of Hsp70 isoforms and identified an as yet unknown N-terminally truncated Hsp70-8 variant.

• Authors: B Zierhut, K Mechtler, W Gartner, T Daneva, W Base, M Weissel, B Niederle, L Wagner
• Journal: Endocrine-related cancer (Endocr Relat Cancer) Vol. 11 Issue 2 Pg. 377-89 (Jun 2004) ISSN: 1351-0088 [Print] England
• PMID: 15163312 (Publication Type: Comparative Study, Journal Article, Research Support, Non-U.S. Gov't)
• Copyright: Copyright 2004 Society for Endocrinology

Chemical References

• Antibodies, Monoclonal
• HSP70 Heat-Shock Proteins
• Recombinant Fusion Proteins

Topics

• Amino Acid Sequence
• Animals
• Antibodies, Monoclonal
• Carcinoid Tumor (metabolism, pathology)
• Electrophoresis, Gel, Two-Dimensional
• HSP70 Heat-Shock Proteins (classification, metabolism)
• Humans
• Insulinoma (immunology, metabolism, pathology)
• Mass Spectrometry
• Mice
• Mice, Inbred BALB C
• Molecular Sequence Data
• Neuroendocrine Tumors (metabolism)
• Pancreatic Neoplasms (metabolism, pathology)
• Pheochromocytoma (metabolism, pathology)
• Recombinant Fusion Proteins (metabolism)
• Sequence Deletion
• Sequence Homology, Amino Acid