Gene expression and protein localisation of calcyclin, a calcium-binding protein of the S-100 family in fresh neuroblastomas

• Published in: European journal of cancer (1990) Vol. 31; no. 4; pp. 499 - 504
• Main Authors: Tonini, G.P., Fabretti, G., Kuznicki, J., Massimo, L., Scaruffi, P., Brisigotti, M., Mazzocco, K.
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 1995
• Subjects: Base Sequence; Calcium-Binding Proteins - genetics; Calcium-Binding Proteins - metabolism; calcyclin; Cell Cycle Proteins; cell differentiation; Cell Differentiation - genetics; gene expression; Gene Expression Regulation, Neoplastic; Humans; Molecular Sequence Data; Neoplasm Proteins - genetics; Neoplasm Proteins - metabolism; neuroblastoma; Neuroblastoma - genetics; Neuroblastoma - metabolism; Polymerase Chain Reaction; retinoic acid; RNA, Messenger - genetics; RNA, Neoplasm - genetics; S-100; S100 Calcium Binding Protein A6; S100 Proteins - metabolism; Tumor Cells, Cultured; S-100; retinoic acid; cell differentiation; calcyclin; neuroblastoma; gene expression; polymerase chain reaction
• ISSN: 0959-8049; 1879-0852
• DOI: 10.1016/0959-8049(95)00043-I

Calcyclin gene, a Ca 2+-binding protein with homology to S-100, has been found to be expressed at different levels in leukaemic cells and in other tumour cells. We recently reported the expression of the gene in human neuroblastoma (NB) cell lines, and suggested a possible role of calcyclin in cell differentiation. To extend our findings, we investigated the expression of the gene in NB cells induced to differentiate by retinoic acid (RA), using the reverse transcriptase-polymerase chain reaction (RT-PCR) technique. Time-course experiments employing LA-N-5 cells showed that calcyclin mRNA appeared 2 h after RA treatment, long before the cells were blocked in the G1 cell-cycle phase and before the neurite-like structures outgrew from the cell bodies. This suggests the involvement of the gene in the early phase of cell differentiation. Furthermore, we investigated mRNA expression in a series of fresh neuroblastomas. NB tumours showed a heterogeneous pattern of calcyclin expression, although calcyclin seemed to be expressed more frequently in cases with a favourable Shimada histology. We also studied the expression of the protein in formalin fixed and paraffin embedded tissues, by using a specific anticalcyclin antibody. The protein was detected in stromal cells which characterise a more mature histological type, and in nerve sheaths, whereas neuroblasts were negative. The tissue that expressed calcyclin protein showed a Schwann-like differentiation and, unlike S-100 protein, calcyclin was expressed in the perineurium.