C. De Nardo and E. Fonsatti contributed equally to this work.
Recombinant transmembrane CD59 (CD59-TM) confers complement resistance to GPI-anchored protein defective melanoma cells†
Article first published online: 14 DEC 2001
Copyright © 2002 Wiley-Liss, Inc.
Journal of Cellular Physiology
Volume 190, Issue 2, pages 200–206, February 2002
How to Cite
De Nardo, C., Fonsatti, E., Sigalotti, L., Calabrò, L., Colizzi, F., Cortini, E., Coral, S., Altomonte, M. and Maio, M. (2002), Recombinant transmembrane CD59 (CD59-TM) confers complement resistance to GPI-anchored protein defective melanoma cells. J. Cell. Physiol., 190: 200–206. doi: 10.1002/jcp.10050
- Issue published online: 4 JAN 2002
- Article first published online: 14 DEC 2001
- Manuscript Accepted: 27 AUG 2001
- Manuscript Received: 10 AUG 2001
- Associazione Italiana per la Ricerca sul Cancro
- Progetto Ricerca Finalizzata awarded by the Italian Ministry of Public Health
Protectin (CD59) is a glycosylphosphatidylinositol (GPI)-anchored cell membrane glycoprotein, broadly expressed on melanocytic cells, that represents the main restriction factor of complement (C)-mediated lysis of human melanoma cells. Levels of CD59 expression may impair the clinical efficacy of C-activating monoclonal antibodies (mAb); thus, we investigated the molecular mechanisms underlying the lack of CD59 expression in selected melanoma cells. Serological and biochemical analyses showed that MeWo melanoma cells expressed CD59 neither at cell surface nor at cytoplasmic levels; however, no critical mutations were identified in their CD59 mRNA. Consistently, MeWo CD59 cDNA (MeWo-CD59) was appropriately translated when transfected into the CD59-positive Mel 100 melanoma cells, and into the CD59-negative Nalm-6 pre-B leukemia cells that acquired resistance to C. In contrast, transfection of MeWo cells with CD59 cDNA from Mel 275 melanoma cells did not induce CD59 expression; however, their transfection with the CD59-TM chimeric construct, obtained by replacing the GPI-anchoring signal of MeWo-CD59 with the transmembrane tail of the human low-density lipoprotein receptor, induced the expression of a C-protective transmembrane form of CD59. These data, together with the absent expression of additional GPI-anchored proteins (i.e., CD55), suggest that defects in the biosynthesis and/or processing of GPI-anchored proteins underlie the lack of CD59 expression in MeWo cells. Further unveiling of the molecular mechanism that turns off CD59 expression in human melanoma cells will help to set-up more effective therapeutic strategies utilizing C-activating mAb in melanoma patients. J. Cell. Physiol. 190: 200–206, 2002. © 2002 Wiley-Liss, Inc.