Abstract
The association of iron with anticancer immunity is unclear. In order to determine the role of iron in anticancer immunity, we manipulated intracellular iron levels of the human MCF-7 and MDA-MB-231 breast cancer cell lines, and measured cytolysis of breast cancer cells by the natural killer cell line NK-92MI, nitric oxide (NO) production, tumor necrosis factor alpha (TNFα) production and gene expression of ferritin heavy chain (FTH1). We found that NK-92MI increased synthesis and release of NO and TNFα into the medium during co-culturing of NK-92MI cells with MCF-7 or MDA-MB-231 cells. Addition of iron inhibited the cytolysis of the breast cancer cell lines. The iron chelator deferoxamine (DFOM) increased NK-92MI cytolysis to MCF-7 or MDA-MB-231 cells. Iron reversed cytotoxicity to breast cancer cells induced by NO, released from S-nitroso-N-acetyl-penicillamine (NO donor). Real time quantitative polymerase chain reaction showed that iron up-regulated the expression of FTH1 and iron chelator DFOM reduced FTH1 expression of MCF-7 and MDA-MB-231 cells. In conclusion, increased iron in cancer cells and their microenvironment protects cancer cells from natural killer cell cytolysis by antagonizing NO- and TNFα-associated cytotoxicity and by up-regulation of ferritin expression in breast cancer cells. Conversely, a decrease in iron concentration caused by DFOM improves natural killer cytolysis of tumor cells.
- Received March 14, 2017.
- Revision received April 9, 2017.
- Accepted April 12, 2017.
- Copyright© 2017, International Institute of Anticancer Research (Dr. George J. Delinasios), All rights reserved