Expression of complement factor H by lung cancer cells: effects on the activation of the alternative pathway of complement
Complement Factor H/biosynthesis
Complement Factor H/immunology
Complement Factor H/metabolism
Lung Neoplasms/immunology
Lung Neoplasms/metabolism
Issue Date: 
American Association for Cancer Research
Ajona D, Castaño Z, Garayoa M, Zudaire E, Pajares MJ, Martinez A, et al. Expression of complement factor H by lung cancer cells: effects on the activation of the alternative pathway of complement. Cancer Res 2004 Sep 1;64(17):6310-6318.
The complement system is important in immunosurveillance against tumors. However, malignant cells are usually resistant to complement-mediated lysis. In this study, we examine the expression of factor H, an inhibitor of complement activation, and factor H-like protein 1 (FHL-1), its alternatively spliced form, in lung cancer. We also evaluate the potential effect of factor H/FHL-1 in the protection of lung cancer cells against the activation of the complement cascade. By Northern blot analysis we demonstrate a high expression of factor H and FHL-1 in most non-small cell lung cancer cell lines, although neuroendocrine pulmonary tumors (small cell lung carcinoma and carcinoid cell lines) had undetectable levels. Western blot analysis of conditioned medium showed the active secretion of factor H and FHL-1 by cells that were positive by Northern blot. Expression of factor H/FHL-1 mRNA was also shown in a series of non-small cell lung cancer biopsies by in situ hybridization. Interestingly, many cultured lung cancer cells were able to bind fluorescence-labeled factor H to their surfaces. Deposition of C3 fragments from normal human serum on H1264, a lung adenocarcinoma cell line, was more efficient when factor H/FHL-1 activity was blocked by specific antibodies. Blocking factor H/FHL-1 activity also enhanced the release of anaphylatoxin C5a and moderately increased the susceptibility of these cells to complement-mediated cytotoxicity. In summary, we demonstrate the expression of factor H and FHL-1 by some lung cancer cells and analyze the contribution of these proteins to the protection against complement activation.

Files in This Item:
14Ajona CancerResearch 2004.pdf
420.38 kB
Adobe PDF

Statistics and impact
0 citas en
0 citas en

Items in Dadun are protected by copyright, with all rights reserved, unless otherwise indicated.