IL-15 and GM-CSF stimulated macrophages enhances phagocytic activity in ENU induced leukemic mice.

Murine splenic macrophage plays a decisive role in host immunity through phagocytosis against pathogens. It was reported that, macrophages also involves in phagocytosis of some tumour cells upon its activation initiated by certain cytokines produced by other immune cell or by indigenously treated. In this study, we have investigated the killing of leukemic blast cells by macrophages upon stimulated with IL-15 and GM-CSF alone or in combination in ENU challenged leukemic murine model. Along with, the release of TNF-α, IL-12 and IFN-γ by macrophages were assayed by ELISA. NO production by macrophages was also investigated. The molecular expressions like GM-CSF and TLRs were investigated for better understand of macrophage-leukemic cell interaction. Result shows that in disease condition macrophages have poor phagocytic activities which may be due to less release of TNF-α, IL-12 and IFN-γ by macrophages. This impaired phagocytic activity in leukemic mice was increase upon stimulation with IL-15 and GM-CSF.

Friedelane, isolated from Pouzolzia indica Gaud. exhibits toxic effect against melanoma.

Melanoma is a predominant cause of skin cancer-related deaths. It was reported that, the methanolic extract of Pouzolzia Indica (P. indica) on chromatography gave five compounds (1-hentriacontanyl palmitate, myricyl alcohol, 6,7-dimethoxycoumarin, trichadonic acid and friedelane), which inhibited the acute promyelocytic leukemia cell lines, NB4, and HT93A. Friedelane was extracted as active compound from methanolic extract of P. indica. In this study, friedelane was tested on murine metastatic B16F10 and B16BL6 melanoma cell lines. To achieve the target, the cell viability using trypan blue exclusion, acridine orange/EtBr staining and cell cytotoxicity were tested using MTT assay. Caspase-3, caspase-9, Cyt-c, BAD and Bax protein were assayed to evidence the apoptosis induction. The compound friedelane shows potent cytotoxic effect against metastatic melanoma mouse cell lines in 10 µg/ml concentration.

IL-3 and GM-CSF modulate functions of splenic macrophages in ENU induced leukemia.

Leukemia is often accompanied by enhanced susceptibility to infection due to compromised B cell and T cell functions. The alterations in macrophage functions in leukemia remain less investigated. Herein, we examined macrophages for their functions and responsiveness to IL-3 and GM-CSF in ENU-induced leukemia in BALB/c mice. We observed that the macrophages from the leukemic mice had less phagocytic activity, reduced chemotactic activity in response to monocyte chemoattractant protein-1(MCP-1), and decreased expression of iNOS, GM-CSF, TLR2, TLR4, IFN-γ and TNF-α. These impaired macrophage functions in leukemic mice were significantly corrected by IL-3 and GM-CSF treatment indicating the therapeutic benefit of these two cytokines in leukemia.

Cytotoxic activity of T lymphocytes is induced upon stimulation with IL-3 plus GM-CSF in animal leukemia model.

Chemotherapy for leukemia has severe toxicity and bone marrow transplantation is both financially and logistically demanding. Therefore, immunotherapy is a feasible and promising approach to treat leukemia. For immunotherapy, cytotoxic T lymphocytes (CTL) against leukemic cells were induced. In BALB/c mice, leukemia was induced by N-ethyl-N'-nitrosourea (ENU). The mice were treated with recombinant IL-3 and GM-CSF - both 5µg/kg/day for four days to induce functional CTL. The IL-3+GM-CSF treatment increased total leukocyte counts, accompanied by significant increase in CTL activity, in the leukemic mice. The IL-3+GM-CSF treatment also enhanced the expression of both p40 and p35 isoforms of IL-12. Perforin and granzyme B expressions were increased in the treated group supporting the T lymphocyte-mediated cytotoxic killing of the target cells. The protein tyrosine kinase (PTK) activity was increased in leukemia but decreased after the treatment with IL-3 and GM-CSF. Interferon gamma (IFN-γ) production was decreased in leukemic condition but increased after the treatment with these colony stimulating factors. These data indicate the anti-leukemic potential of the IL-3 and GM-CSF combination therapy.