Antitumor effect of the combination of manumycin A and Immodin is associated with antiplatelet activity and increased granulocyte tumor infiltration in a 4T1 breast tumor model

Manumycin A is a natural antibiotic isolated from Streptomyces parvulus with broad range of biological activities including antineoplastic activity in several in vitro and in vivo cancer models. Immodin [dialyzable leukocyte extract (DLE)] is a dialysate released from disintegrated blood leukocytes of healthy donors which exerts immunonormalizing effects on cell-mediated immune responses. The aim of the present study was to explore the antitumor potential of the combination of manumycin A and Immodin in an experimental breast cancer model. Experiments were carried using a 4T1 tumor-bearing BALB/c mouse model. Survival analysis, tumor growth, hematological and biochemical profiles, leukocyte differential, phagocytic activity of leukocytes and histology of the primary tumor were examined. The combination treatment suppressed the tumor growth and prolonged the survival of tumor-bearing mice, decreased the number of monocytes, plateletes and plateletcrit in peripheral blood of the tumor-bearing mice and increased the infiltration of neutrophils and eosinophils in the primary tumor. Moreover, individual therapies enhanced the phagocytic activity of monocytes and neutrophils. These findings demonstrate the antitumor effect of the combination of manumycin A and Immodin in 4T1 tumor-bearing mice associated with strong antiplatelet activity and innate immunity activation.

Far-western blotting as a solution to the non-specificity of the anti-erythropoietin receptor antibody

The erythropoietin receptor (EpoR) is a member of the cytokine receptor family. The interaction between erythropoietin (Epo) and EpoR is important for the production and maturation of erythroid cells, resulting in the stimulation of hematopoiesis. The fact that EpoR was also detected in neoplastic cells has opened the question about the relevance of anemia treatment with recombinant Epo in cancer patients. Numerous studies have reported pro-stimulating and anti-apoptotic effects of Epo in cancer cells, thus demonstrating EpoR functionality in these cells. By contrast, a previous study claims the absence of EpoR in tumor cells. This apparent discrepancy is based, according to certain authors, on the use of non-specific anti-EpoR antibodies. With the aim of bypassing the direct detection of EpoR with an anti-EpoR antibody, the present authors propose a far-western blot methodology, which in addition, confirms the interaction of Epo with EpoR. Applying this technique, the presence of EpoR and its interaction with Epo in human ovarian adenocarcinoma A2780 and normal human umbilical vein endothelial cells was confirmed. Furthermore, modified immunoprecipitation of EpoR followed by matrix-assisted laser desorption/ionization-time-of-flight mass spectrometry analysis confirmed a 57 kDa protein as a human Epo-interacting protein in both cell lines.