Signal peptide of eosinophil cationic protein upregulates transforming growth factor-alpha expression in human cells

• Published in: Journal of cellular biochemistry Vol. 100; no. 5; pp. 1266 - 1275
• Main Authors: Chang, Hao-Teng, Kao, Yu-Lin, Wu, Chia-Mao, Fan, Tan-chi, Lai, Yiu-Kay, Huang, Kai-Ling, Chang, Yuo-Sheng, Tsai, Jaw-Ji, Chang, Margaret Dah-Tsyr
• Format: Journal Article
• Language: English
• Published: Hoboken Wiley Subscription Services, Inc., A Wiley Company 01.04.2007
• Subjects: Aspartic Acid Endopeptidases - genetics; Aspartic Acid Endopeptidases - metabolism; Carcinoma, Squamous Cell - metabolism; Culture Media, Conditioned - pharmacology; Enzyme-Linked Immunosorbent Assay; eosinophil cationic protein; Eosinophil Cationic Protein - genetics; Eosinophil Cationic Protein - metabolism; Green Fluorescent Proteins - metabolism; HL-60 Cells; Humans; Protein Sorting Signals - physiology; Receptor, Epidermal Growth Factor - metabolism; Recombinant Fusion Proteins - genetics; Recombinant Fusion Proteins - pharmacology; signal peptide; signal peptide peptidase; Transforming Growth Factor alpha - metabolism; transforming growth factor-alpha; Tumor Cells, Cultured; Up-Regulation
• DOI: 10.1002/jcb.21120
• ISSN: 0730-2312

Eosinophil cationic protein (ECP) is a major component of eosinophil granule protein that is used as a clinical bio‐marker for asthma and allergic inflammatory diseases. Previously, it has been reported that the signal peptide of human ECP (ECPsp) inhibits the cell growth of Escherichia coli (E. coli) and Pichia pastoris (P. pastoris), but not mammalian A431 cells. The inhibitory effect is due to the lack of human signal peptide peptidase (hSPP), a protease located on the endoplasmic reticulum (ER) membrane, in the lower organisms. In this study, we show that the epidermal growth factor receptor (EGFR) is upregulated by the exogenous ECPsp‐eGFP as a result of the increased expression of the transforming growth factor‐alpha (TGF‐α) at both transcriptional and translational levels in A431 and HL‐60 clone 15 cell lines. Furthermore, the N‐terminus of ECPsp fragment generated by the cleavage of hSPP (ECPspM1‐G17) gives rise to over threefold increase of TGF‐α protein expression, whereas another ECPsp fragment (ECPspL18‐A27) and the hSPP‐resistant ECPsp (ECPspG17L) do not show similar effect. Our results indicate that the ECPspM1‐G17 plays a crucial role in the upregulation of TGF‐α, suggesting that the ECPsp not only directs the secretion of mature ECP, but also involves in the autocrine system. J. Cell. Biochem. 100: 1266–1275, 2007. © 2006 Wiley‐Liss, Inc.