Prediction of TP53 mutations by p53 immunohistochemistry and their prognostic significance in gastric cancer.

BACKGROUND: Recently, molecular classifications of gastric cancer (GC) have been proposed that include TP53 mutations and their functional activity. We aimed to demonstrate the correlation between p53 immunohistochemistry (IHC) and TP53 mutations as well as their clinicopathological significance in GC. METHODS: Deep targeted sequencing was performed using surgical or biopsy specimens from 120 patients with GC. IHC for p53 was performed and interpreted as strong, weak, or negative expression. In 18 cases (15.0%) with discrepant TP53 mutation and p53 IHC results, p53 IHC was repeated. RESULTS: Strong expression of p53 was associated with TP53 missense mutations, negative expression with other types of mutations, and weak expression with wild-type TP53 (p<.001). The sensitivity for each category was 90.9%, 79.0%, and 80.9%, and the specificity was 95.4%, 88.1%, and 92.3%, respectively. The TNM stage at initial diagnosis exhibited a significant correlation with both TP53 mutation type (p=.004) and p53 expression status (p=.029). The Kaplan-Meier survival analysis for 109 stage II and III GC cases showed that patients with TP53 missense mutations had worse overall survival than those in the wild-type and other mutation groups (p=.028). Strong expression of p53 was also associated with worse overall survival in comparison to negative and weak expression (p=.035). CONCLUSIONS: Results of IHC of the p53 protein may be used as a simple surrogate marker of TP53 mutations. However, negative expression of p53 and other types of mutations of TP53 should be carefully interpreted because of its lower sensitivity and different prognostic implications.

Efficacy of Mirror Therapy Containing Functional Tasks in Poststroke Patients.

OBJECTIVE: To investigate the effect of mirror therapy containing functional tasks on upper extremity function and activities of daily living in patients with subacute stroke. METHODS: The subjects were randomly divided into two groups: the mirror therapy group (30 patients) and the sham therapy group (30 patients). The mirror therapy group underwent a mirror therapy program together with conventional therapy for 20 minutes per day on 5 days per week for 4 weeks. The control group received a sham conventional therapy program under the same schedule as the mirror therapy group. The Fugl-Meyer Motor Function Assessment (FMA), Brunnstrom motor recovery stage, and Modified Barthel Index (MBI) were evaluated 4 weeks after the treatment. RESULTS: The upper extremity function on the affected side and ability to perform daily life activities after the intervention were significantly improved in both groups. After 4 weeks of intervention, improvements in the FMA (p=0.027) and MBI (p=0.041) were significantly greater in the mirror therapy group than the sham therapy group. CONCLUSION: In this study, we found that the mirror therapy containing functional task was effective in terms of improving the upper extremity functions and activities of daily living in patients with subacute stroke.

Factors related to completed status and seropositivity of hepatitis a immunization among children aged 1-3 years and 6-8 years in South Korea.

This study was designed to identify factors associated with hepatitis A immunization status and seropositivity in Korean children. In-person interviews, reviewing their vaccination cards and testing hepatitis A antibody were conducted with 389 children aged 1-3 years and 544 children aged 6-8 years. In all age groups, earlier birth order was the only significant factor in children receiving either single or both doses of the vaccination. And completion of the second dose of vaccination was a prerequisite for increased seropositivity. Additionally, household income had a positive impact on seropositivity only in children aged 6-8 years. Our findings suggest that presence of an economic barrier is the underlying cause of the decreased hepatitis A vaccination services in Korea. Therefore, hepatitis A vaccine should be included in the essential National Immunization Program.

Novel dihydrobenzofuro[4,5-b][1,8]naphthyridin-6-one derivative, MHY-449, induces apoptosis and cell cycle arrest in HCT116 human colon cancer cells.

Colorectal cancer (CRC) is the second most frequent cancer in men and the third most common cancer in women in Korea. In spite of the significant advances in conventional therapeutic approaches to CRC, most patients ultimately die of their disease. There is a need to develop novel preventive approaches for this malignancy. This study was carried out to investigate the anticancer effect of the diastereoisomeric compounds, MHY-449 and MHY-450, novel dihydrobenzofuro[4,5-b][1,8]naphthyridin-6-one derivatives, on HCT116 human colon cancer cells. MHY-449 exhibited more potent cytotoxicity than MHY-450, against HCT116 cells. Treatment of cells with MHY-449 resulted in growth inhibition and induction of apoptosis in a concentration-dependent manner, and inhibition of proliferation in a time-dependent manner. The induction of apoptosis was observed by decreased cell viability, DNA fragmentation, activation of protein levels involved in death receptors. Moreover, activation of caspase-3, -8 and -9 and cleavage of poly(ADP-ribose) polymerase and alteration in the ratio of Bax/Bcl-2 protein expression was observed. MHY-449 induced G2/M phase arrest in the cell cycle progression which was observed by flow cytometry analysis, and a decrease in the protein expression of cyclin B1 and its activating partners Cdc25c and Cdc2. MHY-449 also caused increase in the expression levels of p53, a tumor suppressor gene, and p21WAF1/CIP and p27KIP, G2/M phase inhibitors. These results suggest that MHY-449 may be a useful candidate for chemo-prevention and/or treatment of colon cancer.

Protective effect of polysaccharide from Hizikia fusiformis against ethanol-induced toxicity.

Polysaccharide extracted from Hizikia fusiformis (Hf-PS-1) exhibited protective effects against ethanol-induced peptic injury. In in vivo assay, the ethanol group exhibited decrease of total glutathione (GSH) and increase of jun N-terminal kinase (JNK) phosphorylation relative to the control group, whereas levels were significantly increased and decreased, respectively, in the Hf-PS-1 group. Hf-PS-1 reduced ethanol-induced gastric injury. In in vitro assay, ethanol induced IEC-6 cells' death in a dose-dependent manner. Ethanol decreased the phosphorylation of Shc and the binding of Grb2 to Shc, and Hf-PS-1 pretreatment increased them. Ethanol also induced the phosphorylation of JNK and extracellular signal-regulated kinase (ERK), whereas Hf-PS-1 pretreatment decreased JNK activation but not ERK. Co-treatment with JNK inhibitor and ethanol decreased GSH levels, indicating that JNK phosphorylation is a critical factor during ethanol-induced injury. Therefore, Hf-PS-1 may be useful to protect against ethanol-induced gastrointestinal injury.

Polysaccharides from Capsosiphon fulvescens stimulate the growth of gastrointestinal cells.

Capsosiphon fulvescens is a green alga that is abundant along the southwest coast of South Korea. Although it is consumed for its purported health-enhancing properties, particularly as a treatment for stomach disorders and hangovers, the health effects of dietary C. fulvescens remain unclear. Polysaccharides extracted from C. fulvescens (Cf-PS) are investigated for their effects on the proliferation of rat small intestinal epithelial IEC-6 cells. Cf-PS stimulated IEC-6 cell proliferation in a dose-dependent manner. Further, Cf-PS treatment induced the translocation of ß-catenin, an effector of the Wnt signaling pathway, from the cytosol to the nucleus and increased the expression of cyclinD1 and c-myc. Cf-PS also induced ERK1/2 phosphorylation, which is activated by mitogenic and proliferative stimuli such as growth factors, but the phosphorylation of JNK and p38 was not enhanced. Therefore, this chapter discusses the effect of Cf-PS on the growth of gastrointestinal cells.

A glycoprotein from Porphyra yezoensis produces anti-inflammatory effects in liposaccharide-stimulated macrophages via the TLR4 signaling pathway.

The purpose of this study was to investigate the antioxidant and anti-inflammatory effects of a glycoprotein isolated from the alga Porphyra yezoensis in LPS-stimulated RAW 264.7 mouse macrophages. First, we extracted a novel material with antioxidant activity from P. yezoensis, confirmed by SDS-PAGE to be a glycoprotein, which we named P. yezoensis glycoprotein (PGP). PGP inhibited the production of NO and ROS and expression of iNOS, COX-2, TNF-α and IL-1ß, which are involved in the pathogenesis of many inflammation-associated human diseases, including septic shock, hemorrhagic shock and rheumatoid arthritis. Next, we determined the mechanisms behind the antioxidant and anti-inflammatory activities of PGP. We focused on the Toll-like receptor 4 (TLR4) signaling pathway because it is well-known to induce the pro-inflammatory proteins that trigger MAPK and NF-κB activation in lipopolysaccharide (LPS)-induced oxidative events. PGP treatment reduced the formation of the TLR4-IRAK4 and TLR4-TRIF binding complexes in response to LPS. Moreover, it inhibited LPS-induced activation and nuclear translocation of NF-κB by abrogating IκB phosphorylation. PGP also suppressed the phosphorylation of ERK1/2 and JNK in a dose-dependent manner. These results suggest that PGP exerts its anti-inflammatory effects by modulating TLR4 signaling and thus inhibiting the activation of NF-κB and MAP kinases.

Polysaccharides from Capsosiphon fulvescens stimulate the growth of IEC-6 Cells by activating the MAPK signaling pathway.

Seaweed extracts show diverse bioactivities, such as antioxidant and antitumor activity. Capsosiphon fulvescens is a green alga that is abundant along the southwest coast of South Korea. Although it is consumed for its purported health-enhancing properties, particularly as a treatment for stomach disorders and hangovers, the health effects of dietary C. fulvescens remain unclear. We extracted polysaccharides from C. fulvescens (Cf-PS), investigated their effects on the proliferation of rat small intestinal epithelial IEC-6 cells, and determined the signaling cascade involved. We cultured IEC-6 cells in the presence of Cf-PS, which stimulated cell proliferation in a dose-dependent manner, and analyzed the Wnt and MAPK signaling pathways, which are related to cell proliferation. Cf-PS treatment induced the translocation of ß-catenin, an effector of the Wnt signaling pathway, from the cytosol to the nucleus and increased the expression of cyclinD1 and c-myc. Cf-PS also induced ERK1/2 phosphorylation, which is activated by mitogenic and proliferative stimuli such as growth factors, but the phosphorylation of JNK and p38 was not enhanced. Our results show that Cf-PS regulates proliferation via stimulating the nuclear translocation of ß-catenin and ERK1/2 activation in intestinal epithelial cells.

A glycoprotein from Laminaria japonica induces apoptosis in HT-29 colon cancer cells.

We isolated a novel glycoprotein from the brown alga Laminaria japonica that has antiproliferative effects on HT-29 colon cancer cells. We also identified the mechanism by which this glycoprotein, named LJGP, induces apoptosis. MTS assays showed that LJGP inhibited the proliferation of several cancer cell lines (AGS, HepG2, HT-29) in a dose-dependent manner. Especially in HT-29 cells, proliferation was significantly decreased. LJGP treatment on HT-29 displayed several apoptotic features, such as DNA fragmentation, sub-G1 arrest, caspase-3 activation, and PARP degradation. Consistent with sub-G1 arrest, LJGP decreased the expression of Cdk2, cyclin E, cyclin D1, PCNA, E2F-1, and phosphorylated pRb. Furthermore, the increase of p27 expression was observed. We also determined that LJGP-induced apoptosis leads to the formation of a death-induced signaling complex of Fas, FADD, and procaspase-8. LJGP induced the reduction of mitochondrial membrane potential with activation of the Bcl-2 family of proteins and caspase-9. These findings suggest that LJGP inhibits HT-29 cell proliferation by inducing apoptosis, which may be mediated via multiple pathways, including the Fas signaling pathway, the mitochondrial pathway, and cell cycle arrest. Therefore, LJGP can be a useful treatment option for colon cancer in humans.

Protective effect of a polysaccharide from Hizikia fusiformis against ethanol-induced cytotoxicity in IEC-6 cells.

In the present study, we examined the signaling pathways related to the ethanol-protective effect of Hf-PS-1 in IEC-6 cells. Ethanol induced the death of IEC-6 cells in a dose-dependent manner, and pretreatment with Hf-PS-1 abrogated the ethanol toxicity. When we examined whether the effect of Hf-PS-1 on ethanol cytotoxicity was associated with insulin growth factor-I receptor signaling pathways, involving mitogen-activated protein kinase (MAPK), we found that ethanol treatment decreased the phosphorylation of Shc and the binding of Grb2 to Shc, and Hf-PS-1 pretreatment increased them. Ethanol treatment also induced the phosphorylation of JNK and ERK, whereas Hf-PS-1 pretreatment decreased JNK activation but not ERK activation. Using a JNK inhibitor (SP600125), we examined GSH levels to determine whether Hf-PS-1 pretreatment mi20 ght protect against ethanol-induced gastric intestinal damage by down-regulating JNK. Co-treatment with SP600125 and ethanol decreased GSH levels, indicating that JNK phosphorylation is a critical factor during ethanol-induced injury and that the effect of Hf-PS-1 occurs via JNK down-regulation. We have thus demonstrated the protective effect of Hf-PS-1 against ethanol-induced cellular damage. Therefore, Hf-PS-1 may be useful as a bio-functional food source to protect against ethanol-induced gastrointestinal injury.

Glycoprotein extraction from Laminaria japonica promotes IEC-6 cell proliferation.

The brown alga Laminaria japonica is frequently consumed in Korea, Japan and China, and has been used for more than a thousand years as a drug in traditional Chinese medicine. In this study, we isolated a novel glycoprotein from L. japonica that stimulates the growth of the IEC-6 normal murine intestinal epithelial cells. We also identified the mechanism by which this glycoprotein, referred to as LJGP, stimulates cell growth. After 24 h of exposure to LJGP, cell proliferation increased in a dose-dependent manner. To further explore the mechanism associated with LJGP-induced cell proliferation, we treated cells for various times with LJGP. We focused on the epidermal growth factor receptor (EGFR) signaling pathway, which is involved in the regulation of cellular proliferation and differentiation, during LJGP-induced cell growth. The results showed that LJGP induced EGFR and Akt activation. Furthermore, LJGP stimulated Shc/Grb2 binding and ERK activation, but inhibited JNK phosphorylation. These results indicate that LJGP stimulates gastrointestinal cell growth by activating the EGFR signaling pathway.

Chemoprotective effects of a protein from the red algae Porphyra yezoensis on acetaminophen-induced liver injury in rats.

Seaweeds contribute to the maintenance of health through their nutritional and medicinal properties. The effects of PYP, a 14 kDa protein isolated from a hot-water extract of the marine alga Porphyra yezoensis, on AAP-induced liver injury in rats was evaluated. AAP induced acute liver injury and AAP-induced hepatotoxicity is the leading cause of liver failure. In this study, male Sprague-Dawley rats were assigned to one of three treatment groups: control, AAP, or AAP + PYP. Compared with the control group, liver tissue from the AAP group showed increased levels of caspase-3 activity and DNA fragmentation, decreased levels of GSH and increased serum GOT/GPT levels. In contrast, treatment with AAP + PYP produced levels of caspase-3 activity, DNA fragmentation, GSH and GOT/GPT that matched the values seen in the control group. It is concluded that PYP may prevent AAP-induced liver injury.

Chemoprotective effect of insulin-like growth factor I against acetaminophen-induced cell death in Chang liver cells via ERK1/2 activation.

The insulin-like growth factor (IGF) system and type-I IGF receptor (IGF-IR) signaling are involved in protecting against chemotherapeutic drug-induced cell death in human hepatoma cells. Acetaminophen (AAP) hepatotoxicity is the leading cause of liver failure, and the prevention of AAP-induced cell death has been the focus of many studies. We determined whether IGF-I could protect against AAP-induced cell death in Chang liver cells and investigated the protective mechanism. Based on the results of MTS assays, LDH release assays, Hoechst 33342 cell staining, and DNA fragmentation experiments, AAP induced cell death in a dose-dependent manner. According to Western blot analysis, treatment with AAP increased the level of poly(ADP-ribose) polymerase (PARP) fragments in cells compared with that in control cells; however, caspase-3, a critical signaling molecule in apoptosis, was not activated after AAP overdose. Moreover, combined treatment with AAP and IGF-I inhibited PARP cleavage, which was consistent with the ability of IGF-I to restore the level of glutathione (GSH) and cell viability in GSH and MTS assays, respectively. We investigated whether the protective effect of IGF-I against AAP cytotoxicity is related to the extracellular signal-related kinase ERK1/2, which is generally activated by mitogenic and proliferative stimuli such as growth factors. Compared with AAP treatment alone, IGF-I and AAP co-treatment increased ERK1/2 phosphorylation but inhibited PARP cleavage. Thus ERK1/2 activation is instrumental in the protective effect of IGF-I against AAP-induced cell death in Chang liver cells.