Antitumor effect of lung cancer vaccine with umbilical blood dendritic cells in reconstituted SCID mice.

Dendritic cells (DCs) are important cells in initiating an immune response. A generation of functional DCs has potential clinical use in treating cancer. However, the source of DCs and patient immunodeficiency with cancer have been hindrances in clinical therapy. We generated DCs from human umbilical cord blood mononuclear cells (UBMCs) with recombinant human granulocyte-macrophage colony stimulating factor, recombinant human interleukin-4, and recombinant human tumor necrosis factor-alpha. The mature DC-A549 lung cancer vaccine (AgL-DC) was prepared through loading A549 lysate, treating with lipopolysaccharide (LPS) and positive selecting with CD83 magnetic beads. AgL-DC can secrete interleukin (IL)-12 and IL-1. Further in vitro analysis showed that AgL-DC notably induced human UBMC lymphocyte proliferation (p < 0.01) by 3-(4,5-dimethylthiazol-z-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, increased the cytotoxic T-lymphocyte (CTL) activity of UBMC lymphocytes against A549 cells (p < 0.05, at effector cells:target cells ratios of 50:1 and 100:1) by lactate dehydrogenase (LDH) cytotoxic assay, and improved production of IL-6 and tumor necrosis factor-beta (p < 0.01, p < 0.05) by enzyme-linked immunosorbent assay. Subsequently, the reconstitute immunity model in severe combined immunodeficiencies (SCID) mice has been established using human UBMC transplantation, and similar trends to results of UBMC in vitro experiments have been shown in lymphocyte proliferation, CTL activity, and IL-6 and tumor necrosis factor-beta secretion levels in these models. AgL-DC also significantly (p < 0.01) increased the antitumor effect in vivo. The tumor infiltrating immunocytes were positively expressed human CD83 and CD3 molecules, and they were negatively expressed in tumor tissue treated with control. These results have demonstrated that umbilical cord DCs are a useful source of vaccine cells for augmenting CTL-mediated cytotoxicity and have potential usefulness in cellular therapy for human cancer in a new vaccination strategy.

[Studies on the enhancement of DC vaccine to mouse Lewis lung cancer by CpG oligonucleotides].

OBJECTIVE: To investigate whether CpG ODN can affect the antitumor responses of DC-tumor cell vaccine against Lewis lung cancer. METHODS: CpG oligonucleotides 1826 (ODN 1826) were used to promote maturation of DCs in vitro. By fusing DCs with Lewis lung carcinoma L3-8 cells, DC-based tumor cell vaccines were developed. To determine the immune responses to the vaccines, T cell proliferation and cytotoxicity were done in vitro. Therapeutic and prophylactic immunization with DC vaccines were performed in C57BL/6 mice bearing Lewis lung carcinoma. RESULTS: Bone marrow cells cultured in the presence of GM-CSF and IL-4 plus additional ODN 1862 appeared typical morphology of DCs. FACS analyses showed that the mean fluorescence index (MFI) of CD40 expression of DCs stimulated with and without CpG ODN was 24 and 11, respectively, and that of CD86 expression was 75 and 33, respectively. IL-12 secreted by DCs cultured with ODN 1826 was 10-fold as high as that without ODN 1826. Significant T-cell proliferation and T cell-mediated cytotoxicity against L3-8 was induced in vitro. Marked inhibition of tumor growth in L3-8 bearing mice was observed upon prophylactic and therapeutic immunizations with the vaccine. CONCLUSION: CpG ODN can enhance the antitumor responses of DC vaccine by promoting DC maturation.

[A study of the inhibition effect of HIFU and its mechanism of action on the proliferation of human breast cancer cells].

OBJECTIVE: To investigate the killing effect of high intensity focused ultrasound (HIFU) on human tumor cells and study the mechanism of its action. METHODS: Human breast cancer cells MCF-7 were treated with different intensity of HIFU in vitro and incubated. The killing effect and proliferation inhibition effect of HIFU on tumor cells were investigated with the methods of trypan blue exclusion assay, MTT assay and colony formation assay. And the cell cycle, apoptotic cells and the expressions of P53, BCL-2, FAS and HSP70 were measured with flow cytometry. RESULTS: After HIFU treatment, the death rates of cancer cell increased, the proliferation of cell waned (P < 0.05), the number of colony formation decreased (P < 0.001), the cell number increased in G0/G1 phase (P < 0.05) and decreased in S phase, the apoptotic indices increased (P < 0.01), the expression of HSP70 was enhanced, and no significant changes of P53, BCL-2, FAS expressions were found (P > 0.05). CONCLUSION: HIFU produces significant effects such as killing, proliferation inhibition and colony formation inhibition on human breast cancer cells; its mechanism of action may be associated with the inhibition of DNA synthesis. In addition, HIFU treatment can induce apoptotic cell death, which may not be associated with the mediation and regulation of P53, BCL-2 and FAS genes.