Eosinophil Granular Protein(s) Modulate Tumor Metastasis Marker Gene Expression

摘要

MCF-7 breast cancer multicellular tumor spheroids have been used as the model system for evaluating the effect of eosinophil granular proteins as well as pro-/anti-inflammatory cytokines on tumor growth and proliferation. More specifically this study attempts to evaluate the effect of these proteins on the expression of oncogenes which modulate growth and proliferation of tumors. These oncogenes include erbB2/Her-2-neu, cyclin D1, cyclin E1, p21, p27, p53, e-cadherin and n-cadherin. Eosinophil cell lines established from an allergic asthmatic individual were batch cultured and used to isolate eosinophil granular proteins (MBP, EPO and ECP). Additional protein isolation efforts include perforin and granzyme b which are also produced by eosinophils and which are known to be a mechanism by which cytotoxic T cells and natural killer cells kill tumor targets. SDS-PAGE analysis of 18 and 21 HCl extractions from eosinophil granules (spontaneously released in culture supernatants and cellular extracts, respectively) revealed molecular weight bands for MBP, EPO, and ECP in 14 of the supernatant granule extracts and in 20 of the 21 cellular granule extracts. MCF-7 spheroids were treated with 10-fold increasing suboptimum doses of MBP and cytokines IL-4, TNF-alpha, IL-10 and IL-12 individually for 24, 48 and 72 hrs. IL-4, MBP and IL-12 downregulated expression of all genes except erbB2; TNF-alpha downregulated erbB2 (5ng),CyD1, CyEl, p21, p27 and p53, while IL-10 downregulated CyE1, p21, p53 and e-cadherin expression. The data strongly suggest the potential anti-cancer effects of MBP at very low doses. The possible collaborative effect of MBP,other granular proteins and the cytokines studied with known anti-cancer drugs to effectuate greater efficacy of anti-cancer drug activity may be the direction for these studies.