interleukin-8 and Leukemia--Erythroblastic--Acute

hUCB-MSC (human umbilical cord blood-derived mesenchymal stem cells) offer an attractive alternative to bone marrow-derived MSC for cell-based therapy by being less invasive a source of biological material. We have evaluated the effect of hUCB-MSC on the proliferation of K562 (an erythromyeloblastoid cell line) and the cytokine secretion pattern of hUCB-MSC. Co-culturing of hUCB-MSC and K562 resulted in inhibition of proliferation of K562 in a dose-dependent manner. However, the anti-proliferative effect was reduced in transwells, suggesting the importance of direct cell-to-cell contact. hUCB-MSC inhibited proliferation of K562, arresting them in the G0 /G1 phase. NO (nitric oxide) was not involved in the hUCB-MSC-mediated tumour suppression. The presence of IL-6 (interleukin 6) and IL-8 were obvious in the hUCB-MSC conditioned media, but no significant increase was found in 29 other cytokines. Th1 cytokines, IFNα (interferon α), Th2 cytokine IL-4 and Th17 cytokine, IL-17 were not secreted by hUCB-MSC. There was an increase in the number of hUCB-MSC expressing the latent membrane-bound form of TGFβ1 co-cultured with K562. The anti-proliferative effect of hUCB-MSC was due to arrest of the growth of K562 in the G0 /G1 phase. The mechanisms underlying increased IL-6 and IL-8 secretion and LAP (latency-associated peptide; TGFβ1) by hUCB-MSC remains unknown.

Topics: Cell Communication; Cell Line, Tumor; Cell Proliferation; Cell- and Tissue-Based Therapy; Coculture Techniques; Contact Inhibition; G1 Phase Cell Cycle Checkpoints; Humans; Interleukin-6; Interleukin-8; Leukemia, Erythroblastic, Acute; Mesenchymal Stem Cells; Nitric Oxide; Transforming Growth Factor beta1; Umbilical Cord

Embryonic development associated gene (EDAG), which is overexpressed in hematopoietic neoplasms and leukemia cell lines, has been reported to participate in the leukemia cell differentiation and proliferation. This study investigated whether retrovirus-mediated transfer of a siRNA against EDAG can reduce the growth of leukemia cells which highly express EDAG in vitro and in vivo. The stable transfected cells were identified with RT-PCR, the effect of EDAG/siRNA on the growth of the human erythroleukemia cell line HEL was analyzed by MTT assay, and angiogenic factor IL-8 release was evaluated by ELISA and RT-PCR. The results showed that EDAG/siRNA can silence the expression of EDAG in HEL cells. Down-regulation of EDAG expression by retrovirus-mediated siRNA inhibited the cell proliferation and tumor growth. Knockdown of EDAG expression by siRNA is also associated with decreased expression of the anti-angiogenic factor IL-8, suggesting that EDAG stimulates tumor growth at least in part by regulating angiogenesis. This study suggests that siRNA-mediated gene silencing of EDAG could potentially be a therapeutic strategy for EDAG over-expressing leukemia cells.

Topics: Base Sequence; Cell Division; Cell Line, Tumor; Chromosome Mapping; Chromosomes, Human, Pair 9; Down-Regulation; Gene Expression Regulation, Neoplastic; Humans; Interleukin-8; Kinetics; Leukemia, Erythroblastic, Acute; Molecular Sequence Data; Nuclear Proteins; Retroviridae; Reverse Transcriptase Polymerase Chain Reaction; RNA, Small Interfering; Tetradecanoylphorbol Acetate; Transfection

The erythrocyte chemokine receptor is a cell surface protein that binds a wide array of chemokines including interleukin-8 (IL-8), melanoma growth stimulating activity (MGSA), monocyte chemotactic protein-1 (MCP-1), and RANTES (Regulated on Activation, Normal T Expressed and Secreted). This protein has also been identified as the Duffy blood group antigen, a cell surface receptor for the malarial parasite Plasmodium vivax. In the present study, we have identified a chemokine receptor-like binding protein in a human erythroleukemic cell line (HEL), which, based on its molecular properties, may be related to the erythrocyte chemokine receptor. Saturation binding studies with 125I-IL-8 revealed a single class of IL-8 binding sites in HEL cells with a KD of 7.4 +/- 1.9 nM and a receptor density of 12,818 +/- 965 binding sites/cell. In competition studies unlabeled IL-8 MGSA, MCP-1, and RANTES were fully able to inhibit the binding of 125I-IL-8 to HEL cells. Chemical cross-linking with radiolabeled IL-8 resulted in a cross-linked species of 60 kDa in membranes from HEL cells. The labeling was specific since it was inhibited by pre-incubation with 1 microM unlabeled IL-8 or MGSA. A monoclonal antibody (Fy6) to the human erythrocyte Duffy blood group antigen/chemokine receptor blocked the binding of IL-8 and other chemokines to the HEL cell chemokine receptor-like binding protein. Cell membranes from HEL cells and from erythrocyte ghosts were subjected to SDS-PAGE and analyzed by Western blotting with anti-Fy6. The antibody bound to a molecule with a molecular mass of 50 kDa in HEL cell membranes and 40 kDa in erythrocyte ghosts. Northern blot analysis of mRNA revealed that the HEL chemokine-binding protein hybridized to a cDNA probe to the Duffy antigen/chemokine receptor.

Topics: Binding Sites; Brain; Cells, Cultured; Chemokine CCL2; Chemokine CCL5; Chemokine CXCL1; Chemokines, CXC; Chemotactic Factors; Cytokines; Erythrocytes; Growth Substances; Humans; Intercellular Signaling Peptides and Proteins; Interleukin-8; Kidney; Leukemia, Erythroblastic, Acute; Lymphokines; Receptors, Cytokine; RNA, Messenger; Spleen; Tumor Cells, Cultured

Normal as well as transformed epidermal cells (EC) have recently been reported to produce a cytokine--EC-derived thymocyte-activating factor (ETAF), which according to its biologic as well as biochemical properties is indistinguishable from macrophage-derived interleukin 1 (IL 1). In the present study, the effect of supernatants (SN) derived from normal EC and a human squamous carcinoma cell (SCC) line were tested for their effects on natural killer (NK) cell activity. EC- as well as SCC-derived SN were able to augment in vitro NK cell activity of peripheral blood lymphocytes against K 562 cells. In contrast, adherent cell-derived, IL 1-containing SN did not affect NK cell activity. Upon high-pressure liquid chromatography (HPLC) gel filtration, ETAF and the EC-derived NK cell activity-augmenting factor (ENKAF) exhibited a similar m.w. However, by using reverse-phase HPLC, ETAF and ENKAF eluted as distinct peaks of activity, indicating that SCC cell-derived ENKAF is different from ETAF. Furthermore, ENKAF does not contain interleukin 2 (IL 2) or interferon (IFN) activity. The enhancement of NK cell activity was dose dependent and evident after 20 hr of preincubation of effector cells. Pretreatment of target cells with ENKAF did not affect the susceptibility of the target cells. The NK activity of large granular lymphocytes (LGL) purified by discontinuous Percoll gradient centrifugation and further depleted of high-affinity sheep erythrocyte rosetting cells was enhanced by ENKAF. In contrast, no NK cell activity was expressed by LGL-depleted T cell populations before or after treatment with ENKAF. In a single cell cytotoxicity assay in agarose, the number of lymphocyte binding to K 562 was not affected by ENKAF, but the frequency of dead conjugated target cells and presumably of active killer cells was increased by pretreatment with ENKAF. Additional incubation of LGL with ETAF did not further increase ENKAF-mediated augmentation of NK activity. In contrast to ETAF, ENKAF was not chemotactic for polymorphonuclear leukocytes. These results indicate that normal as well as transformed EC release a unique cytokine--ENKAF--which augments NK cell activity of LGL but is distinct from ETAF, IL 2, and IFN.

Topics: Biological Products; Carcinoma, Squamous Cell; Cell Line; Chemotactic Factors; Cytokines; Cytotoxicity, Immunologic; Epidermis; Humans; Interleukin-1; Interleukin-8; Killer Cells, Natural; Leukemia, Erythroblastic, Acute; Temperature