Natural killer anti-tumor activity

Recent studies further suggest that LF may have a role in the development and progression of tumors (Tsuda et al., 2002). Orally administered bovine LF has been found to inhibit the development of tumors in the colon, oesophagus and lung carcinogenesis in a rat or mouse model, but the mode of action remains to be resolved (Sekine et al., 1997 Ushida et al., 1999 Kuhara et al., 2000). The anti-tumor activity may be mediated by the enhanced cytokine production or the activating effect on natural killer cells and be independent of the iron-saturation level. 

Recently it was demonstrated that transfection of tumor cells with an antitumor peptide induced a protective immune reponse. Inoculation of mice with murine BD-2-transfected leukemia cells enhanced cytotoxic T lymphoc)des (CTL) and natural killer (NK) anti-tumor activity, with augmented IL-12 and IFN-y production. Animals vaccinated with transfected cells were protected against a challenge with parental cells (50% protection) and the vaccination generated leukemia-specific memory CTL [210]. 

In addition to direct effects on genes regulating inflammation, glucocorticoids also inhibit the transcription factors that initiate synthesis of pro-inflammatory cytokines (e.g., interleukin-1, tumor necrosis factor), enzymes (e.g., COX-2, nitric oxide synthase), and receptor proteins (e.g., natural killer receptors).17,87,89 Glucocorticoids may also exert some of their effects via a membrane-bound receptor that regulates activity of macrophages, eosinophils, T lymphocytes, and several other types of cells involved in the inflammatory response.89 Consequently, glucocorticoids affect many aspects of inflammation, and their powerful anti-inflammatory effects in rheumatoid arthritis result from their ability to blunt various cellular and chemical components of the inflammatory response. 

---