Cheung-Seog Park

MicroRNA and gene expression analysis of melatonin-exposed human breast cancer cell lines indicating involvement of the anticancer effect.

Abstract:  MicroRNAs (miRNAs) are small, noncoding RNAs that play a crucial role in regulation of gene expression. Recent studies have shown that miRNAs implicated in initiation and progression of various human cancers, including breast cancer and also analysis of miRNA expression profiles in cancer provide new insights into potential mechanisms of carcinogenesis. Melatonin, N‐acetyl‐5‐methoxytryptamine, is synthesized by the pineal gland in response to the dark/light cycle and has been known to act as a synchronizer of the biological clock. Melatonin has a variety of therapeutic effects, such as immunomodulatory actions, anti‐inflammatory effects, and antioxidant actions. Furthermore, melatonin is reported to have an anticancer function including suppression of the metabolism of tumor cells and induction of tumor suppressor genes in cancer cells, including breast cancer cells. In this study, we determined whether miRNAs play a role in regulation of various gene expression responses to melatonin in MCF‐7 human breast cancer cells. We examined whole‐genome miRNA and mRNA expression and found that 22 miRNAs were differentially expressed in melatonin‐treated MCF‐7 cells. We further identified a number of mRNAs whose expression level shows a high inverse correlation with miRNA expression. The Gene Ontology (GO) enrichment analysis and pathways analysis were performed for identification of the signaling pathways and biological processes affected by differential expression of miRNA and miRNA‐related genes. Our findings suggested that melatonin may modulate miRNA and gene expression as an anticancer mechanism in human breast cancer cells.

Extracts from Citrus unshiu promote immune-mediated inhibition of tumor growth in a murine renal cell carcinoma model.

AIM OF THIS STUDY Citrus unshiu (Satsuma mandarin, SM) is a citrus fruit the peel of which has been used as a traditional Chinese medicine to treat common cold, relieve exhaustion, and cancer. In this study, we examined how effectively the content and peel extracts of SM can suppress cancer growth. The mechanism underlying cancer-suppressing properties of SM was investigated in tumor-bearing mice with renal carcinoma cell, Renca. MATERIALS AND METHODS Effectiveness of SM in tumor suppression was evaluated by measuring size of tumor mass in tumor-bearing mice treated with various doses of SM content and peel extracts. Proliferation of tumor cells and splenocytes was determined by MTT assay and [³H]TdR uptake, respectively. Relevant immunological mechanisms were chased by assaying cytokines including TGF-β, IL-6, IFN-γ, and TNF-α by ELISA. RESULTS The content and peel extracts of SM inhibited the growth of tumor cells in tumor-bearing mice. Especially, average tumor volume of two groups treated with 3 and 30 mg peel extracts per mouse weight (kg) were significantly decreased to 52.32% (p<0.05) and 68.72% (p<0.01), respectively. To identify tumor regression mechanism, anti-tumor cytokines measured in Con A-activated splenocytes from tumor-bearing mice. IFN-γ was increased in both of the peel extract-treated groups, while TNF-α, which had been decreased by tumor growth, was rescued to the normal level in SM content and peel extracts-treated groups. However, SM content and peel extracts did not inhibit proliferation and tumor-proliferative cytokines including TGF-β and IL-6 production of tumor cells. CONCLUSION These results indicate that SM content and peel extracts have anti-tumor properties in the tumor-bearing murine model. The mechanism underlying the anti-tumor effects of SM extracts is strongly suggested to be via boosting cytokines such as IFN-γ and TNF-α, enhancing immune-mediated anti-tumor properties.

Omega-3 fatty acid-derived mediator, Resolvin E1, ameliorates 2,4-dinitrofluorobenzene-induced atopic dermatitis in NC/Nga mice

Atopic dermatitis (AD) is a common inflammatory skin disease for which few effective treatments are available. Resolvin E1 (RvE1; 5S,12R,18R-trihydroxy-6Z,8E,10E,14Z,16E-eicosapentaenoic acid) is an endogenous lipid mediator derived from omega-3 fatty eicosapentaenoic acid, which is a potent inhibitor of inflammation. AD-like skin lesion was induced by repetitive skin contact with DNFB in NC/Nga mice and the effects of RvE1 were evaluated on the basis of histopathological findings of skin, ear swelling and cytokine production of CD4(+) T cells. Intraperitoneal injection of RvE1 for one week after DNFB challenge significantly lowered ear swelling and improved back skin lesions. In addition, RvE1 significantly suppressed production of interferon-gamma (IFN-γ) and interleukin-4 (IL-4) by activated CD4(+) T cells and serum IgE level. Furthermore, RvE1 reduced DNFB-induced infiltration of eosinophils, mast cells, CD4(+) T cells, and CD8(+) T cells in skin lesions. Therefore, RvE1 may suppress the development of AD-like skin lesions in DNFB-treated NC/Nga mice by reducing IL-4 and IFN-γ of activated CD4(+) T cells and serum IgE levels and infiltration of immune cells to skin lesion.

Effect of Perilla frutescens var. acuta Kudo and rosmarinic acid on allergic inflammatory reactions

Allergy is characterized by an overreaction of the immune system. Perilla frutescens leaf extract has been reported to exhibit antiallergic inflammatory activity. To investigate precisely the effect and mechanism of 30% ethanol extract powder of P. frutescens var. acuta Kudo (EPPF) and rosmarinic acid (RA), a component of EPPF in allergic rhinitis and rhinoconjunctivitis, the antiallergic effects of EPPF and RA were analyzed using in vivo and in vitro models. Cytokine production was analyzed by means of an enzyme-linked immunosorbent assay. Cytokine expression was analyzed via reverse transcription-polymerase chain reaction and Western blotting. Transcription factor and caspase-1 activity were analyzed by a luciferase assay and caspase-1 assay, respectively. The number of nasal, ear and eye rubs after an ovalbumin (OVA) challenge in OVA-sensitized mice was significantly higher than that in OVA-unsensitized mice. Increased number of rubs was inhibited by administration of EPPF or RA. Increased levels of IgE in the serum, spleen and nasal mucosa of OVA-sensitized mice were reduced by EPPF or RA administration. The histamine level was also reduced by EPPF or RA administration in the serum of OVA-sensitized mice. Protein levels and mRNA expressions of interleukin (IL)-1β, IL-6 and tumor necrosis factor-α were inhibited by EPPF or RA administration in the nasal mucosa tissue or spleen of OVA-sensitized mice. In EPPF or RA-administered mice, the mast cell and eosinophil infiltration increase as caused by OVA-sensitization was decreased. In addition, EPPF or RA inhibited both cyclooxygenase-2 protein expression and caspase-1 activity in the same nasal mucosa tissue. In activated human mast cells, nuclear factor-kappa B (NF-κB)/Rel A and caspase-1 activation increased, whereas NF-κB/Rel A and caspase-1 activation was inhibited after a treatment of EPPF or RA. These results indicate that EPPF and RA ameliorate allergic inflammatory reactions such as allergic rhinitis and allergic rhinoconjunctivitis.

Production and applications of rosmarinic acid and structurally related compounds

Rosmarinic acid (α-o-caffeoyl-3,4-dihydroxyphenyllactic acid; RA) is a naturally occurring hydroxylated compound commonly found in species of the subfamily Nepetoideae of the Lamiaceae and Boraginaceae, such as Rosmarinus officinalis, Salvia officinalis, and Perilla frutescens. RA is biosynthesized from the amino acids l-phenylalanine and l-tyrosine by eight enzymes that include phenylalanine ammonia lyase and cinnamic acid 4-hydroxylase. RA can also be chemically produced by the esterification of caffeic acid and 3,4-dihydroxyphenyllactic acid. RA and its numerous derivatives containing one or two RA with other aromatic moieties are well known and include lithospermic acid, yunnaneic acid, salvianolic acid, and melitric acid. Recently, RA and its derivatives have attracted interest for their biological activities, which include anti-inflammatory, anti-oxidant, anti-angiogenic, anti-tumor, and anti-microbial functions. Clinically, RA attenuates T cell receptor-mediated signaling, attenuates allergic diseases like allergic rhinitis and asthma, and 2,4-dinitrofluorobenzene-induced atopic dermatitis-like symptoms, protects from neurotoxicity, and slows the development of Alzheimer’s disease. These attributes have increased the demand for the biotechnological production and application of RA and its derivatives. The present review discusses the function and application of RA and its derivatives including the molecular mechanisms underlying clinical efficacy.

Production of antibodies with peptide-CpG-DNA-liposome complex without carriers

BackgroundThe screening of peptide-based epitopes has been studied extensively for the purpose of developing therapeutic antibodies and prophylactic vaccines that can be potentially useful for treating cancer and infectious diseases such as influenza virus, malaria, hepatitis B, and HIV. To improve the efficacy of antibody production by epitope-based immunization, researchers evaluated liposomes as a means of delivering vaccines; they also formulated adjuvants such as flagella and CpG-DNA to enhance the magnitude of immune responses. Here, we provide a potent method for peptide-based epitope screening and antibody production without conventional carriers.ResultsWe present that a particular form of natural phosphodiester bond CpG-DNA encapsulated in a specific liposome complex (Lipoplex(O)) induces potent immunomodulatory activity in humans as well as in mice. Additionally, Lipoplex(O) enhances the production of IgG2a specific to antigenic protein in mice. Most importantly, immunization of mice with several peptides co-encapsulated with Lipoplex(O) without carriers significantly induces each peptide-specific IgG2a production in a TLR9-dependent manner. A peptide-specific monoclonal antibody produced against hepatocellular carcinoma-associated antigen has functional effects on the cancer cells.ConclusionsOur overall results show that Lipoplex(O) is a potent adjuvant and that complexes of peptide and Lipoplex(O) are extremely useful for B cell epitope screening and antibody production without carriers. Therefore, our strategy may be promptly used for the development of therapeutic antibodies by rapid screening of potent B cell epitopes.

Prevention and therapy of hepatocellular carcinoma by vaccination with TM4SF5 epitope-CpG-DNA-liposome complex without carriers.

Although peptide vaccines have been actively studied in various animal models, their efficacy in treatment is limited. To improve the efficacy of peptide vaccines, we previously formulated an efficacious peptide vaccine without carriers using the natural phosphodiester bond CpG-DNA and a special liposome complex (Lipoplex(O)). Here, we show that immunization of mice with a complex consisting of peptide and Lipoplex(O) without carriers significantly induces peptide-specific IgG2a production in a CD4+ cells- and Th1 differentiation-dependent manner. The transmembrane 4 superfamily member 5 protein (TM4SF5) has gained attention as a target for hepatocellular carcinoma (HCC) therapy because it induces uncontrolled growth of human HCC cells via the loss of contact inhibition. Monoclonal antibodies specific to an epitope of human TM4SF5 (hTM4SF5R2-3) can recognize native mouse TM4SF5 and induce functional effects on mouse cancer cells. Pre-immunization with a complex of the hTM4SF5R2-3 epitope and Lipoplex(O) had prophylactic effects against tumor formation by HCC cells implanted in an mouse tumor model. Furthermore, therapeutic effects were revealed regarding the growth of HCC when the vaccine was injected into mice after tumor formation. These results suggest that our improved peptide vaccine technology provides a novel prophylaxis measure as well as therapy for HCC patients with TM4SF5-positive tumors.

Oral administration of Uncariae rhynchophylla inhibits the development of DNFB-induced atopic dermatitis-like skin lesions via IFN-γ down-regulation in NC/Nga mice.

ETHNOPHARMACOLOGICAL RELEVANCE Uncariae rhynchophylla (UR) is an herb which has blood pressure lowering and anti-inflammatory effects and has been prescribed traditionally to treat stroke and vascular dementia. AIM OF STUDY In the present study, we examined whether UR suppress Atopic dermatitis (AD)-like skin lesions in NC/Nga mice treated with 2, 4-dinitrofluorobenzene (DNFB) under SPF conditions. MATERIAL AND METHODS The effect of UR in DNFB- treated NC/Nga mice was determined by measuring the skin symptom severity, levels of serum IgE, and of the amounts of IL-4 and IFN-gamma secreted by activated T cells in draining lymph nodes. RESULTS Oral administration of UR to DNFB-treated NC/Nga mice was found to inhibit ear thickness increases and the skin lesions induced by DNFB. IFN-gamma production by CD4+ T cells from the lymph nodes of DNFB-treated NC/Nga mice was significantly inhibited by UR treatment, although levels of IL-4 and total IgE in serum were not. CONCLUSION UR may suppress the development of AD-like dermatitis in DNFB-treated NC/Nga mice by reducing IFN-gamma production.

Selective GSK-3β inhibitors attenuate the cisplatin-induced cytotoxicity of auditory cells

Glycogen synthase kinase-3 (GSK-3) plays an important role in the regulation of apoptosis. However, the role of GSK-3 in the auditory system remains unknown. Here we examined whether the GSK-3-specific inhibitors, SB 216763 and LiCl, could protect against cisplatin-induced cytotoxicity of auditory cells. GSK-3 was activated by cisplatin treatment of HEI-OC1 cells. SB 216763 or LiCl treatments inhibited cisplatin-induced apoptosis in a dose-dependent manner and activated caspase-9, -8 and -3. In rat primary explants of the organ of Corti, SB 216763 or LiCl treatments completely abrogated the cisplatin-induced destruction of outer hair cell arrays. Administration of SB 216763 or LiCl inhibited cochlear destruction and the production of tumor necrosis factor-alpha (TNF-alpha), interleukin-1beta (IL-1beta) and IL-6 in cisplatin-injected mice. Furthermore, administration of SB 216763 or LiCl reduced the thresholds of the auditory brainstem response (ABR) in cisplatin-injected mice. Collectively, these results suggest that cisplatin-induced ototoxicity might be associated with modulation of GSK-3 activation.

Melatonin suppresses acrolein‐induced IL‐8 production in human pulmonary fibroblasts

Abstract:  Cigarette smoke (CS) causes harmful alterations in the lungs and airway structures and functions that characterize chronic obstructive pulmonary disease (COPD). In addition to COPD, active cigarette smoking causes other respiratory diseases and diminishes health status. Furthermore, recent studies show that, α, β‐unsaturated aldehyde acrolein in CS induces the production of interleukin (IL)‐8, which is known to be related to bronchitis, rhinitis, pulmonary fibrosis, and asthma. In addition, lung and pulmonary fibroblasts secrete IL‐8, which has a chemotactic effect on leukocytes, and which in turn, play a critical role in lung inflammation. On the other hand, melatonin regulates circadian rhythm homeostasis in humans and has many other effects, which include antioxidant and anti‐inflammatory effects, as demonstrated by the reduced expressions of iNOS, IL‐1β, and IL‐6 and increased glutathione (GSH) and superoxide dismutase activities. In this study, we investigated whether melatonin suppresses acrolein‐induced IL‐8 secretion in human pulmonary fibroblasts (HPFs). It was found that acrolein‐induced IL‐8 production was accompanied by increased levels of phosphorylation of Akt and extracellular signal‐regulated kinases (ERK1/2) in HPFs, and that melatonin suppressed IL‐8 production in HPFs. These results suggest that melatonin suppresses acrolein‐induced IL‐8 production via ERK1/2 and phosphatidylinositol 3‐kinase (PI3K)/Akt signal inhibition in HPFs.