Association between Promoter Polymorphisms of TFF1, TFF2, and TFF3 and the Risk of Gastric and Diffuse Gastric Cancers in a Korean Population

Gastric cancer is one of the most common cancers in the world. The aims of this study were to evaluate the association between polymorphisms in TFF gene family, TFF1, TFF2, and TFF3 and the risk of gastric cancer (GC) and GC subgroups in a Korean population via a case-control study. The eight polymorphisms in TFF gene family were identified by sequencing and genotyped with 377 GC patients and 396 controls by using TaqMan genotyping assay. The rs184432 TT genotype of TFF1 was significantly associated with a reduced risk of GC (odds ratio, [OR) = 0.45; 95% confidence interval, [CI] = 0.25-0.82; P = 0.009), more protective against diffuse-type GC (OR = 0.20; 95% CI = 0.05-0.89; P = 0.035) than GC (OR = 0.34; 95% CI = 0.14-0.82; P = 0.017) in subjects aged < 60 yr, and correlated with lymph node metastasis negative GC and diffuse-type GC (OR = 0.44; 95% CI = 0.23-0.86; P = 0.016 and OR = 0.20; 95% CI = 0.05-0.87; P = 0.031, respectively). In addition, a decreased risk of lymph node metastasis negative GC and diffuse-type GC was observed for rs225359 TT genotype of TFF1 (OR = 0.46, 95% CI = 0.24-0.88; P = 0.020 and OR = 0.21, 95% CI = 0.05-0.88; P = 0.033, respectively). These findings suggest that the rs184432 and rs225359 polymorphisms in TFF1 have protective effects for GC and contribute to the development of GC in Korean individuals.

Expression Changes of Endothelin-1, Endothelin Receptor A and B in the Cochlea after Noise Exposure / 대한이비인후과학회지

BACKGROUND AND OBJECTIVES: There are several evidences of reduced cochlea blood flow after noise exposure in the cochlea. However, the pathophysiology of blood flow change is still obscure, and endothelins, proteins that constrict blood vessels and play a key role in vascular homeostasis using its receptors may have importance in this respect. In this study, we investigated the expression changes of endothelin-1 (ET-1), endothelin receptor A (ETAR) and B (ETBR) according to auditory threshold change after noise exposure. MATERIALS AND METHOD: Mice were exposed to different noise to generate transient (group 2) and permanent threshold shift (group 3), respectively. Auditory threshold shifts were evaluated with auditory brainstem response and expression changes of ET-1, ETAR and ETBR after noise exposure were evaluated by immunohistochemistry and real time RT-PCR. RESULTS: After noise exposure, the increased ET-1, ETAR and ETBR immunoreactivities were observe in stria vascularis, spiral ligament and spiral ganglion neuron. ET-1 mRNA expressions increased after noise exposure in both group 2 and group 3 compared to those of the control group. At 2 weeks after noise exposure, however, the ET-1 mRNA expressions in group 3 increased compared to that of the control but decreased compared to that of group 2. On the other hand, ETAR mRNA expression increased at 2 weeks after noise exposure in both groups, just after noise exposure in group 2 and at 2 weeks after noise exposure in group 3. CONCLUSION: These results suggest that expression changes of ET-1, ETAR and ETBR might be associated with hearing threshold shift and recovery after noise exposure in the cochlea.

Disruption of Microtubules Sensitizes the DNA Damage-induced Apoptosis Through Inhibiting Nuclear Factor kappaB (NF-kappaB) DNA-binding Activity

The massive reorganization of microtubule network involves in transcriptional regulation of several genes by controlling transcriptional factor, nuclear factor-kappa B (NF-kappaB) activity. The exact molecular mechanism by which microtubule rearrangement leads to NF-kappaB activation largely remains to be identified. However microtubule disrupting agents may possibly act in synergy or antagonism against apoptotic cell death in response to conventional chemotherapy targeting DNA damage such as adriamycin or comptothecin in cancer cells. Interestingly pretreatment of microtubule disrupting agents (colchicine, vinblastine and nocodazole) was observed to lead to paradoxical suppression of DNA damage-induced NF-kappaB binding activity, even though these could enhance NF-kappaB signaling in the absence of other stimuli. Moreover this suppressed NF-kappaB binding activity subsequently resulted in synergic apoptotic response, as evident by the combination with Adr and low doses of microtubule disrupting agents was able to potentiate the cytotoxic action through caspase-dependent pathway. Taken together, these results suggested that inhibition of microtubule network chemosensitizes the cancer cells to die by apoptosis through suppressing NF-kappaB DNA binding activity. Therefore, our study provided a possible anti-cancer mechanism of microtubule disrupting agent to overcome resistance against to chemotherapy such as DNA damaging agent.

Long-term Activation of c-Jun N-terminal Kinase through Receptor Interacting Protein is Associated with DNA Damage-induced Cell Death

Activation of c-Jun N-terminal kinase (JNK), a member of the mitogen-activated protein kinase family, is an important cellular response that modulates the outcome of the cells which are exposed to the tumor necrosis factor (TNF) or the genotoxic stress including DNA damaging agents. Although it is known that JNK is activated in response to genotoxic stress, neither the pathways to transduce signals to activate JNK nor the primary sensors of the cells that trigger the stress response have been identified. Here, we report that the receptor interacting protein (RIP), a key adaptor protein of TNF signaling, was required to activate JNK in the cells treated with certain DNA damaging agents such as adriamycin (Adr) and 1-beta-D-arabinofuranosylcytosine (Ara-C) that cause slow and sustained activation, but it was not required when treated with N-methyl-N-nitro-N-nitrosoguanidine (MNNG) and short wavelength UV, which causes quick and transient activation. Our findings revealed that this sustained JNK activation was not mediated by the TNF (tumor necrosis factor) receptor signaling, but it required a functional ATM (ataxia telangiectasia) activity. In addition, JNK inhibitor SP-600125 significantly blocked the Adr-induced cell death, but it did not affect the cell death induced by MNNG. These findings suggest that the sustained activation of JNK mediated by RIP plays an important role in the DNA damage-induced cell death, and that the duration of JNK activation relays a different stress response to determine the cell fate.

Prevention of TNF-induced necrotic cell death by rottlerin through a Nox1 NADPH oxidase

Previous studies have demonstrated that rottlerin, a specific PKCdelta inhibitor, potentiates death receptor- mediated apoptosis through a cytochrome c-dependent or -independent pathway. However, its ability to regulate necrotic cell death, as well as the underlying mechanism, remains unknown. We found that in murine fibrosarcoma L929 cells, treatment with rottlerin protected the cells against TNF-induced necrosis, whereas it sensitized the cells to apoptosis induced by co-treatment with Hsp90 inhibitor geldanamycin and TNF, in a manner independent of its ability to inhibit PKC-delta. TNF treatment induced rapid accumulation of mitochondrial superoxide (O2") through the Nox1 NADPH oxidase when cells undergo necrosis. Moreover, pretreatment with rottlerin failed to induce the GTP-bound form of small GTPase Rac1 by TNF treatment, and subsequently suppressed mitochondrial O2(-) production and poly(ADP-ribose) polymerase activation, thus inhibiting necrotic cell death. Therefore, our study suggests that Nox1 NADPH oxidase is a new molecular target for anti-necrotic activity of rottlerin upon death-receptor ligation.

Effects of Proinflammatory Cytokines and Natural Products on Mucin Release from Cultured Hamster Tracheal Surface Epithelial Cells

In this study, we investigated whether TNF-alpha, IL-1beta, CTMA (carboxymethyl trimethylammonium) and LPD (Lup-20[29]-ene-3beta, 28-diol) affect mucin release from airway goblet cells and compared the activities of these agents with the inhibitory action of PLL and the stimulatory action of ATP on mucin release. Confluent primary hamster tracheal surface epithelial (HTSE) cells were metabolically radiolabeled with 3H-glucosamine for 24 h and chased for 30 min in the presence of varying concentrations of each agent to assess the effects on 3H-mucin release. The results were as follows: TNF-alpha, CTMA and LPD increased mucin release at the highest concentration, but IL-1beta did not. We conclude that CTMA and LPD can stimulate mucin release by directly acting on airway mucin-secreting cells, and suggest that these agents should be further investigated for the possible use as mild expectorants during the treatment of chronic airway diseases.

Caffeic Acid Phenethyl Ester Inhibits the PKC-Induced IL-6 Gene Expression in the Synoviocytes of Rheumatoid Arthritis Patients

To gain insight on the role of pro-inflammatory cytokines in the pathogenesis and treatment of rheumatoid arthritis (RA), the phorbol 12-myristate 13-acetate (PMA) -induced IL-6 gene expression and the effect of caffeic acid phenethyl ester (CAPE) on the PMA-induced IL-6 gene expression were investigated in human fibroblast-like synoviocytes (FLSs). Synovial tissue samples were obtained from rheumatoid arthritis patients, and FLSs were isolated. The cells were stimulated with PMA (100 nM) for 6 hrs to induce IL-6 gene. The cells were pretreated with CAPE (20, 50, 100 microM) prior to PMA treatment. PMA increased IL-6 RNA expression, binding activities of transcription factors (NF-kappaB, AP-1) to IL-6 promoter, and IL-6 promoter activity. However, CAPE inhibited PMA-induced IL-6 mRNA expression in dose-dependent manner, and also inhibited the increased binding activities of transcription factors to IL-6 promoter and IL-6 promoter activity. These results suggest that CAPE might regulate PKC-mediated IL-6 expression and inflammatory reactions in RA.

Consistent and Specific Suppression of Mucin Release from Cultured Hamster Tracheal Surface Epithelial Cells by Poly-L-Lysine

Poly-L-lysine (PLL) was reported to suppress mucin release from airway goblet cells during 30 min treatment period. In this study, we investigated whether PLL consistently suppresses mucin release from cultured airway goblet cells during 24 h after 30 min treatment and also specifically suppresses the release of mucin without any effects on the other releasable glycoproteins. Confluent primary hamster tracheal surface epithelial (HTSE) cells were metabolically radiolabeled with 3H-glucosamine for 24 h and chased for 30 min in the presence of varying concentrations of PLL to assess the effects on 3H-mucin release and on the total elution profile of the treated culture medium. The total mucin content during 24 h after 30 min treatment of PLL was assesed to investigate the consistency of effects. PLL did not affect the release of the other releasable glycoproteins whose molecular weights were less than mucin, and decreased the total mucin content during 24 h after 30 min treatment. We conclude that PLL can specifically suppress mucin release from cultured airway goblet cells and the suppression on mucin release is consistent. This finding suggests that PLL might be used as a specific airway mucin-regulating agent by directly acting on airway mucin-secreting cells.

Diclofenac inhibits IFN-gamma plus lipopolysaccharide-induced iNOS gene expression via suppression of NF-kappaB activation in RAW 264.7 macrophages

Diclofenac, a phenylacetic acid derivative, is a widely used non-steroidal anti-inflammatory drug (NSAID) to provide effective relief of inflammation and pain. Nitric oxide (NO) synthesized by inducible nitric oxide synthase (iNOS) has been implicated as a mediator of inflammation. We examined the inhibitory effects of diclofenac on the induction of iNOS in RAW 264.7 macrophages which were activated with lipopolysaccharide (LPS) plus interferon-gamma (IFN-gamma). Treatment of RAW 264.7 cells with diclofenac and other NSAIDs (aspirin and indomethacin) significantly inhibited NO production and iNOS protein expression induced by LPS plus IFN-gamma. Also, diclofenac but not aspirin and indomethacin, inhibited iNOS mRNA expression and nuclear factor-kappa B (NF-kappaB) binding activity concentration-dependently. Furthermore, transfection of RAW 264.7 cells with iNOS promoter linked to a CAT reporter gene revealed that only diclofenac inhibited the iNOS promoter activity induced by LPS plus IFN-gamma through the NF-kappaB sites of iNOS promoter. Taken together, these suggest that diclofenac may exert its anti-inflammatory effect by inhibiting iNOS gene expression at the transcriptional level through suppression of NF-kappaB activation.

Role of NF- kappaB binding sites in the regulation of inducible nitric oxide synthase by tyrosine kinase

In macrophages, lipopolysaccharide (LPS) alone or in combination with interferon- gamma (IFN- gamma) has been shown to release a nitric oxide (NO) through the increase of the transcription of the inducible nitric oxide synthase (iNOS) gene. To investigate the exact intracellular signaling pathway of the regulation of iNOS gene transcription by LPS plus IFN- gamma, the effects of protein tyrosine kinase (PTK) inhibitor and protein kinase C (PKC) inhibitors on NO production, iNOS mRNA expression, nuclear factor- kappaB (NF- kappaB) binding activity and the promoter activity of iNOS gene containing two NF- kappaB sites have been examined in a mouse macrophage RAW 264.7 cells. LPS or IFN- gamma, stimulated NO production, and their effect was enhanced synergistically by mixture of LPS and IFN- gamma. The PTK inhibitor such as tyrphostin reduced LPS plus IFN- gamma-induced NO production, iNOS mRNA expression and NF- kappaB binding activity. In contrast, PKC inhibitors such as H-7, Ro-318220 and staurosporine did not show any effect on them. In addition, transfection of RAW 264.7 cells with iNOS promoter linked to a CAT reporter gene revealed that tyrphostin inhibited the iNOS promoter activity through the NF- kappaB binding site, whereas PKC inhibitors did not. Taken together, these suggest that PTK, but not PKC pathway, is involved in the regulation of the iNOS gene transcription through the NF- kappaB sites of iNOS promoter in RAW 264.7 macrophages by LPS plus IFN- gamma.

(3H)Ryanodine binding sites of SR vesicles of the chicken pectoral muscle

To investigate the properties of ryanodine binding sites of the bird skeletal SR vesicles, SDS PAGE, purification of RyR, and (3H)ryanodine binding study were carried out in the SR vesicles prepared from the chicken pectoral muscle. The chicken SR vesicles have two high molecular weight (HMW) protein bands as in eel SR vesicles on SDS PAGE. The HMW bands on SDS PAGE were found in the (3H) ryanodine peak fraction (Fr3-5) obtained from the purification step of the ryanodine receptor protein. Bmax and KD of the chicken (3H)ryanodine binding sites were 12.52 pmol/mg protein and 14.53 nM, respectively. Specific (3H)ryanodine binding was almost maximal at 50~100 micrometer Ca2+, but was not increased by 5 mM AMP and not inhibited by high Ca2+. Binding was significantly inhibited by 20~100 micrometer ruthenium red and 1 mM tetracaine, but slightly inhibited by Mg2+. From the above results, it is suggested that chicken SR vesicles have the ryanodine binding sites to which the binding of ryanodine is almost maximal at 50~10 micrometer Ca2+, is significantly inhibited by ruthenium red and tetracaine, slightly inhibited by Mg2+, but not affected by AMP and not inhibited by high Ca2+.