Ho-Keun Kwon

Cinnamon extract induces tumor cell death through inhibition of NFκB and AP1

BackgroundCinnamomum cassia bark is the outer skin of an evergreen tall tree belonging to the family Lauraceae containing several active components such as essential oils (cinnamic aldehyde and cinnamyl aldehyde), tannin, mucus and carbohydrate. They have various biological functions including anti-oxidant, anti-microbial, anti-inflammation, anti-diabetic and anti-tumor activity. Previously, we have reported that anti-cancer effect of cinnamon extracts is associated with modulation of angiogenesis and effector function of CD8+ T cells. In this study, we further identified that anti-tumor effect of cinnamon extracts is also link with enhanced pro-apoptotic activity by inhibiting the activities NFκB and AP1 in mouse melanoma model.MethodsWater soluble cinnamon extract was obtained and quality of cinnamon extract was evaluated by HPLC (High Performance Liquid Chromatography) analysis. In this study, we tested anti-tumor activity and elucidated action mechanism of cinnamon extract using various types of tumor cell lines including lymphoma, melanoma, cervix cancer and colorectal cancer in vitro and in vivo mouse melanoma model.ResultsCinnamon extract strongly inhibited tumor cell proliferation in vitro and induced active cell death of tumor cells by up-regulating pro-apoptotic molecules while inhibiting NFκB and AP1 activity and their target genes such as Bcl-2, BcL-xL and survivin. Oral administration of cinnamon extract in melanoma transplantation model significantly inhibited tumor growth with the same mechanism of action observed in vitro.ConclusionOur study suggests that anti-tumor effect of cinnamon extracts is directly linked with enhanced pro-apoptotic activity and inhibition of NFκB and AP1 activities and their target genes in vitro and in vivo mouse melanoma model. Hence, further elucidation of active components of cinnamon extract could lead to development of potent anti-tumor agent or complementary and alternative medicine for the treatment of diverse cancers.

Targeted chemoimmunotherapy using drug-loaded aptamer-dendrimer bioconjugates

We reported an innovative, targeted chemoimmuno drug-delivery system. Although chemoimmunotherapy, as an alternative to or in combination with conventional therapeutic systems, has been in the forefront of recent oncological research, as presently configured, such systems face several major obstacles for efficient clinical application. Here, we establish a novel nano-platform for effective chemoimmunotherapy designed to overcome the drawbacks of conventional cancer therapies, describing a delivery system based on a dendrimer and a single-strand DNA-A9 PSMA (prostate-specific membrane antigen) RNA aptamer hybrid. Employing these vehicles, we demonstrate the promising possibility of this chemoimmuno therapeutic system against prostate cancer in in vivo and in vitro models.

Cinnamon extract suppresses tumor progression by modulating angiogenesis and the effector function of CD8+ T cells.

Cinnamon is one of the most widely used herbal medicines with diverse bioactive effects. However, little evidence has been reported about the potential anti-tumor effects of cinnamon. In vitro and in vivo system, cinnamon treatment strongly inhibited the expression of pro-angiogenic factors and master regulators of tumor progression not only in melanoma cell lines but also in experimental melanoma model. In addition, cinnamon treatment increased the anti-tumor activities of CD8(+) T cells by increasing the levels of cytolytic molecules and their cytotoxic activity. In conclusion, cinnamon extract has the potential to be an alternative medicine for tumor treatment.

Lactobacillus casei potentiates induction of oral tolerance in experimental arthritis

Probiotics have been shown to exert beneficial effects on modulation of diverse diseases. However, no information is available for the effect of probiotics in the induction of oral tolerance in autoimmune diseases. The main purpose of this study was to elucidate whether Lactobacillus casei (L. casei) affect the induction of oral tolerance in experimental rheumatoid arthritis (RA). Type II collagen (CII) alone or together with L. casei was orally administered into collagen-induced arthritis (CIA) rats, and its effects on the clinical and histopathological aspects of RA were investigated. Co-administration of L. casei with CII more effectively suppressed clinical symptoms, paw swelling, lymphocyte infiltration and destruction of cartilage tissues of experimental arthritis than the rats treated with CII alone. The enhanced therapeutic efficacy was associated with an increase in anti-inflammatory cytokines (IL-10 and TGF-beta) while decreasing pro-inflammatory cytokines (IL-1beta, IL-2, IL-6, IL-12, IL-17, IFN-gamma and TNF-alpha). Co-administration of L. casei with CII more effectively suppressed CII-reactive T cell proliferation and the levels of Th1-type IgG isotypes (IgG2a and IgG2b), while up-regulating Foxp3 expression levels and the population of Foxp3(+) CD4(+) T cells. Our study provides evidence that L. casei could potentiate antigen-specific oral tolerance and suppress Th1-type immune responses of arthritic inflammation.

Interaction of Ets-1 with HDAC1 Represses IL-10 Expression in Th1 Cells

IL-10 is a multifunctional cytokine that plays a crucial role in immunity and tolerance. IL-10 is produced by diverse immune cell types, including B cells and subsets of T cells. Although Th1 produce IL-10, their expression levels are much lower than Th2 cells under conventional stimulation conditions. The potential role of E26 transformation-specific 1 (Ets-1) transcription factor as a negative regulator for Il10 gene expression in CD4+ T cells has been implicated previously. In this study, we investigated the underlying mechanism of Ets-1–mediated Il10 gene repression in Th1 cells. Compared with wild type Th1 cells, Ets-1 knockout Th1 cells expressed a significantly higher level of IL-10, which is comparable with that of wild type Th2 cells. Upregulation of IL-10 expression in Ets-1 knockout Th1 cells was accompanied by enhanced chromatin accessibility and increased recruitment of histone H3 acetylation at the Il10 regulatory regions. Reciprocally, Ets-1 deficiency significantly decreased histone deacetylase 1 (HDAC1) enrichment at the Il10 regulatory regions. Treatment with trichostatin A, an inhibitor of HDAC family, significantly increased Il10 gene expression by increasing histone H3 acetylation recruitment. We further demonstrated a physical interaction between Ets-1 and HDAC1. Coexpression of Ets-1 with HDAC1 synergistically repressed IL-10 transcription activity. In summary, our data suggest that an interaction of Ets-1 with HDAC1 represses the Il10 gene expression in Th1 cells.

Swiprosin‐1 is expressed in mast cells and up‐regulated through the protein kinase CβI/η pathway

Swiprosin‐1 exhibits the highest expression in CD8+ T cells and immature B cells and has been thought to play a role in lymphocyte physiology. Here we report that swiprosin‐1 is also expressed in mast cells and up‐regulated in both in vitro cultured mast cells by phorbol ester and in vivo model tissues of passive cutaneous anaphylaxis and atopic dermatitis. Targeted inhibition of the specific protein kinase C (PKC) isotypes by siRNA revealed that PKC‐βI/η are involved in the expression of swiprosin‐1 in the human mast cell line HMC‐1. In contrast, down‐regulation of swiprosin‐1 by A23187 or ionomycin suggests that calcium‐signaling plays a negative role. The ectopic expression of swiprosin‐1 augmented PMA/A23187‐induced NF‐κB promoter activity, and resulted in increased expression of cytokines. Moreover, knock‐down of swiprosin‐1 attenuated PMA/A23187‐induced cytokine expression. Collectively, these results suggest that swiprosin‐1 is a PKC‐βI/η‐inducible gene and it modulates mast cell activation through NF‐κB‐dependent pathway. J. Cell. Biochem. 108: 705–715, 2009.

Prophylactic Effect of Probiotics on the Development of Experimental Autoimmune Myasthenia Gravis

Probiotics are live bacteria that confer health benefits to the host physiology. Although protective role of probiotics have been reported in diverse diseases, no information is available whether probiotics can modulate neuromuscular immune disorders. We have recently demonstrated that IRT5 probiotics, a mixture of 5 probiotics, could suppress diverse experimental disorders in mice model. In this study we further investigated whether IRT5 probiotics could modulate the progression of experimental autoimmune myasthenia gravis (EAMG). Myasthenia gravis (MG) is a T cell dependent antibody mediated autoimmune disorder in which acetylcholine receptor (AChR) at the neuromuscular junction is the major auto-antigen. Oral administration of IRT5 probiotics significantly reduced clinical symptoms of EAMG such as weight loss, body trembling and grip strength. Prophylactic effect of IRT5 probiotics on EMAG is mediated by down-regulation of effector function of AChR-reactive T cells and B cells. Administration of IRT5 probiotics decreased AChR-reactive lymphocyte proliferation, anti-AChR reactive IgG levels and inflammatory cytokine levels such as IFN-γ, TNF-α, IL-6 and IL-17. Down-regulation of inflammatory mediators in AChR-reactive lymphocytes by IRT5 probiotics is mediated by the generation of regulatory dendritic cells (rDCs) that express increased levels of IL-10, TGF-β, arginase 1 and aldh1a2. Furthermore, DCs isolated from IRT5 probiotics-fed group effectively converted CD4+ T cells into CD4+Foxp3+ regulatory T cells compared with control DCs. Our data suggest that IRT5 probiotics could be applicable to modulate antibody mediated autoimmune diseases including myasthenia gravis.

Immunomodulatory effect of water soluble extract separated from mycelium of Phellinus linteus on experimental atopic dermatitis

BackgroundComplementary and alternative medicine (CAM) is becoming a popular treatment for modulating diverse immune disorders. Phellinus linteus (P. linteus) as one of the CAMs has been used to modulate cancers, inflammation and allergic activities. However, little evidence has been shown about its underlying mechanism of action by which it exerts a beneficial role in dermatological disease in vivo. In this study, we examined the immunomodulatory effects of P. linteus on experimental atopic dermatitis (AD) and elucidated its action mechanism.MethodsThe immunomodulatory effect of total extract of P. linteus on IgE production by human myeloma U266B1 cells was measured by ELISA. To further identify the effective components, P. linteus was fractionated into methanol soluble, water soluble and boiling water soluble extracts. Each extract was treated to U266B1 cells and primary B cells to compare their inhibitory effects on IgE secretion. To test the in vivo efficacy, experimental atopic dermatitis (AD) was established by alternative treatment of DNCB and house dust mite extract into BALB/c mice. Water soluble extract of P. linteus (WA) or ceramide as a positive control were topically applied to ears of atopic mouse every day for 2 weeks and progression of the disease was estimated by the following criteria: (a) ear thickness, clinical score, (b) serum total IgE, IgG and mite specific IgE level by ELSIA, (c) histological examination of ear tissue by H&E staining and (d) cytokine profile of total ear cells and CD4+ T cells by real time PCR and ELSIA.ResultsTreatment of total extracts of P. linteus to U266B1 inhibited IgE secretion. Among the diverse extracts of P. linteus, water soluble extract of P. linteus (WA) significantly reduced the IgE production in primary B cells and B cell line U266B1. Moreover, treatment of WA reduced AD symptoms such as ear swelling, erythema, and dryness and decreased recruitment of lymphocyte into the inflamed site. Interestingly WA treatment significantly reduced IgE level without affecting IgG levels and also down-regulated the levels of pathogenic cytokines (IL-4, IL-13, IL-12 and IFN-γ) and chemokines (CCL17 and CCL22) involved in AD development.ConclusionsOur study indicates that protective effect of water soluble extract of P. linteus in atopic dermatitis is mediated by inhibiting IgE production and expression of AD associated pathogenic cytokines as well as chemokines, suggesting the beneficial effect of P. linteus to modulate allergic skin disease.

Different molecular complexes that mediate transcriptional induction and repression by FoxP3

FoxP3 conditions the transcriptional signature and functional facets of regulatory T cells (Treg cells). Its mechanism of action, whether as an activator or a repressor, has remained unclear. Here, chromatin analysis showed that FoxP3 bound active enhancer elements, not repressed chromatin, around loci over- or under-expressed in Treg cells. We evaluated the impact of a panel of FoxP3 mutants on its transcriptional activity and interactions with DNA, transcriptional cofactors and chromatin. Computational integration, confirmed by biochemical interaction and size analyses, showed that FoxP3 existed in distinct multimolecular complexes. It was active and primarily an activator when complexed with the transcriptional factors RELA, IKZF2 and KAT5. In contrast, FoxP3 was inactive when complexed with the histone methyltransferase EZH2 and transcription factors YY1 and IKZF3. The latter complex partitioned to a peripheral region of the nucleus, as shown by super-resolution microscopy. Thus, FoxP3 acts in multimodal fashion to directly activate or repress transcription, in a context- and partner-dependent manner, to govern Treg cell phenotypes.

A Novel Splicing Variant of Mouse Interleukin (IL)-24 Antagonizes IL-24-induced Apoptosis

Alternative splicing of mRNA enables functionally diverse protein isoforms to be expressed from a single gene, allowing transcriptome diversification. Interleukin (IL)-24/MDA-7 is a member of the IL-10 gene family, and FISP (IL-4-induced secreted protein), its murine homologue, is selectively expressed and secreted by T helper 2 lymphocytes. A novel splice variant of mouse IL-24/FISP, designated FISP-sp, lacks 29 nucleotides from the 5′-end of exon 4 of FISP. The level of FISP-sp expression is 10% of the level of total primary FISP transcription. Unlike FISP, FISP-sp does not induce growth inhibition and apoptosis. FISP-sp is exclusively localized in endoplasmic reticulum, and its expression is up-regulated by endoplasmic reticulum stress. Our results suggest that the novel splicing variant FISP-sp dimerizes with FISP and blocks its secretion and inhibits FISP-induced apoptosis in vivo.