CM1 Ligation Induces Apoptosis via Fas-FasL Interaction in Ramos Cells, but via Down-regulation of Bcl-2 and Subsequent Decrease of Mitochondrial Membrane Potential in Raji Cells

BACKGROUND: CM1 (Centrocyte/-blast Marker I) defined by a mAb developed against concanavalin-A activated PBMC, is expressed specifically on a subpopulation of centroblasts and centrocytes of human germinal center (GC) B cells. Burkitt lymphoma (BL) is a tumor consisting of tumor cells with the characteristics of GC B cell. Previously we reported that CM1 ligation with anti-CM1 mAb induced apoptosis in Ramos (IgM(high)) and Raji (IgM(low)) cells. METHODS & RESULTS: In the present study, we observed that CM1 ligation with anti-CM1 mAb induced Fas ligand and Fas expression in Ramos cells, but not in Raji cells. Furthermore, anti-Fas blocking antibody, ZB4, blocked CM1-mediated apoptosis effectively in Ramos cells, but not in Raji cells. Increased mitochondrial membrane permeabilization, which was measured by DiOC6, was observed only in Raji cells. In contrast to no significant change of Bax known as pro-apoptotic protein, anti-apoptotic protein Bcl-2 was significantly decreased in Raji cells. In addition, we observed that CM1 ligation increased release of mitochondrial cytochrome c and upregulated caspase-9 activity in Raji cells. CONCLUSION: These results suggest that apoptosis induced by CM1-ligation is mediated by Fas-Fas ligand interaction in Ramos cells, whereas apoptosis is mediated by down-regulation of Bcl-2 and subsequent decrease of mitochondrial membrane potential in Raji cells.

Inhibition of Cell Migration by Corticotropin-Releasing Hormone (CRH) in Human Natural Killer Cell Line, NK-92MI

BACKGROUND: Natural killer (NK) cells are CD3 (-) CD14 (-) CD56 (+) lymphocytes. They play an important role in the body's innate immune response. They can induce spontaneous killing of cancer cells or virus-infected cells via the Fas/Fas ligand or the granzyme/perforin systems. The corticotropin-releasing hormone (CRH) is an important regulator for the body's stress response. It promotes proliferation and migration of various cancer cells through the CRH type 1 receptor under stress, and also inhibits NK or T cell activity. However, the relationship of CRH and NK cell migration to the target has not been confirmed. Herein, we study the effect of CRH on NK cell migration. METHODS: We used the human NK cell line, NK-92MI, and tested the expression of CRH receptor type 1 on NK-92MI by RT-PCR. This was to examine the effect of CRH on tumor and NK cell migration, thus NK cells (NK-92MI) were incubated with or without CRH and then each CRH treated cell's migration ability compared to that of the CRH untreated group. RESULTS: We confirmed that CRH receptor type 1 is expressed in NK-92MI. CRH can decrease NK cell migration in a time-/dose-dependent manner. CONCLUSION: These data suggest CRH can inhibit NK cell migration to target cells.

Enhancement of the Stability and Skin Penetration of Vitamin C by Polyphenol

BACKGROUND: It is necessary for human beings to uptake vitamin C through diet or supplements. It is also well-known that vitamin C plays an important role in the prevention of scurvy, enhancement of collagen synthesis and anti-tumor immune response. In addition, there are several recent reports regarding the effective role of vitamin C on the regulation of allergic responses, such as atopic dermatitis and asthma. However, the effective therapeutic and preventive measures using vitamin C are not established yet, since vitamin C is seriously unstable in aqueous solution. Therefore, we have investigated the best way to maintain the stability of vitamin C. METHODS: After we making a mixture of polyphenol (0.001, 0.01, 0.1%) and vitamin C (1 mM), the mixtures were placed at room temperature both with/without light protection. And then the concentration of ascorbic acid was measured with HPLC. To analyze the in vivo effect of vitamin C on the regulation of skin allergic reaction, polyphenol (0.1%)-vitamin C (1 mM) mixture was applied to the skin and the production of histamine from mast cell was analyzed by Evans blue dye staining. RESULTS: We have found that the polyphenol has preventive power of oxidation of vitamin C. In addition, the production of histamine was suppressed by the polyphenol (0.1%)-vitamin C (1 mM) mixture. CONCLUSION: We have reached the conclusion that our study suggests the research guideline for the therapy of atopic dermatitis through vitamin C.

Enhancement of Cell Migration by Corticotropin-Releasing Hormone (CRH) in Human Gastric Cancer Cell Line, MKN-28

BACKGROUND: Corticotropin-Releasing Hormone (CRH), an important regulator of stress response, has a potent immunoregulatory effect with the ability to promote the growth of various cancer through CRH receptor type 1 under stress. Although the metastasized cancers through cell migration are more aggressive than the primary cancers, little is known about the effect of CRH on cell migration. Gastric cancer is prone to metastasize to other tissues and it is reported that gastric cancer is response to various stresses such as oxidative stress. Herein, we studied the relationship between CRH and gastric cancer cell migration. METHODS: We used gastric cancer cell line, MKN-28 and tested the CRH receptor type 1 expression on MKN-28 by RT-PCR. To examine the change in the ability of migration by CRH in MKN-28, cells were incubated with CRH and then migration ability was measured using a cell migration assay. RESULTS: We confirmed that CRH receptor type 1 was expressed in MKN-28 and HaCaT cells. The migration ability of MKN-28 cells was increased by CRH in a time-, dose- dependent manner. CONCLUSION: These data suggest that CRH increases migration ability in gastric cancer cell line and that CRH may be a critical regulator in the metastasis of gastric cancer cell.

The Emerging Role of Natural Killer Cells in Innate and Adaptive Immunity

In the early host defense system, effector function of natural killer (NK) cells results in natural killing against target cells such as microbe-infected, malignant, and certain allogenic cells without prior stimulation. NK cell cytotoxicity is selectively regulated by homeostatic prevalence between a repertoire of both activating and inhibitory receptors, and the discrimination of untransformed cells is achieved by recognition of major histocompatibility complex (MHC) class I alleles through inhibitory signals. Although it is well known that the bipotential T/NK progenitors are derived from the common precusor, functional mechanisms in terms of the development of NK cells remain to be further investigated. NK cells are mainly involved in innate immunity, but recent studies have been reported that they also play a critical role in adaptive immune responses through interaction with dendritic cells (DC). This interaction will provide effector functions and development of NK cells, and elucidation of its precise mechanism may lead to therapeutic strategies for effective treatment of several immune diseases.