Sung Joon Lee

The Cytotoxicity of Kahweol in HT-29 Human Colorectal Cancer Cells Is Mediated by Apoptosis and Suppression of Heat Shock Protein 70 Expression

Although coffee is known to have antioxidant, anti-inflammatory, and antitumor properties, there have been few reports about the effect and mechanism of coffee compounds in colorectal cancer. Heat shock proteins (HSPs) are molecular chaperones that prevent cell death. Their expression is significantly elevated in many tumors and is accompanied by increased cell proliferation, metastasis and poor response to chemotherapy. In this study, we investigated the cytotoxicity of four bioactive compounds in coffee, namely, caffeine, caffeic acid, chlorogenic acid, and kahweol, in HT-29 human colon adenocarcinoma cells. Only kahweol showed significant cytotoxicity. Specifically, kahweol increased the expression of caspase-3, a pro-apoptotic factor, and decreased the expression of anti-apoptotic factors, such as Bcl-2 and phosphorylated Akt. In addition, kahweol significantly attenuated the expression of HSP70. Inhibition of HSP70 activity with triptolide increased kahweol-induced cytotoxicity. In contrast, overexpression of HSP70 significantly reduced kahweol-induced cell death. Taken together, these results demonstrate that kahweol inhibits colorectal tumor cell growth by promoting apoptosis and suppressing HSP70 expression.

An electron microscopic study--correlation of gastroesophageal reflux disease and laryngopharyngeal reflux.

Laryngopharyngeal reflux (LPR) originates from regurgitation of gastric contents, a mechanism seemingly identical to gastroesophageal reflux disease (GERD). Some researchers postulate a connection between LPR and GERD, whereas some assert LPR is a disease apart from GERD. We examined symptoms of GERD from LPR patients, and performed gastrointestinal endoscopy and transmission electron microscopy (TEM) to evaluate GERD findings from these patients.

Ethanol-induced DNA damage and repair-related molecules in human intestinal epithelial Caco-2 cells

The acute administration of ethanol to intestinal epithelial cells causes increased intestinal permeability and the translocation of endotoxins. The changes caused by ethanol in intestinal cells may be related to oxidative stress and DNA damage. However, DNA damage and repair-related molecules which act against stresses, including ethanol, have not been fully investigated in intestinal cells. Heat shock proteins (Hsps) are involved in the recovery and protection from cell damage and may be associated with DNA repair. Therefore, the aim of our study was to investigate cytotoxicity, DNA damage and the expression of DNA repair-related molecules, antioxidant proteins and Hsps in intestinal cells exposed to ethanol. Human intestinal Caco-2 cells were incubated with 1–8% ethanol for 1 h. Cell viability and DNA damage were determined using the MTT and comet assays, respectively. We measured DNA repair-related molecules, including DNA polymerase β, apurinic/apyrimidinic endonuclease/redox factor-1 (APE/Ref-1), growth arrest and DNA damage 45α (GADD45α) and proliferating cell nuclear antigen (PCNA), in Caco-2 cells using western blot analysis. We also measured glutathione peroxidase-1 (GPx-1), peroxiredoxin-1 (PRX-1), superoxide dismutase-2 (SOD-2), Hsp10, Hsp27, Hsp60, heat shock cognate (Hsc)70, Hsp70 and Hsp90. The viability of the Caco-2 cells exposed to ethanol decreased at concentrations ≥7% (P<0.05). The Olive tail moment, indicating DNA damage, increased dose dependently in ≥3% ethanol (P<0.05). Among the DNA repair proteins, the expression of PCNA and APE/Ref-1 increased significantly at 1% ethanol. Antioxidant enzymes, including GPx-1, PRX-1 and SOD-2, had an increased expression at 1% ethanol. Hsp10, Hsp27 and Hsp70 expression also increased significantly at 1% ethanol. In conclusion, the expression of DNA repair molecules, antioxidants and Hsps increased in intestinal Caco-2 cells exposed to low concentrations of ethanol. In particular, PCNA, APE/Ref-1, Hsp10, Hsp27 and Hsp70 were sensitive to low ethanol concentrations, indicating that they may be useful in evaluating the DNA repair and cytoprotective effects of the drug against stress in intestinal cells.

Apocynin Suppresses Lipopolysaccharide‐Induced Inflammatory Responses Through the Inhibition of MAP Kinase Signaling Pathway in RAW264.7 Cells

Apocynin, an inhibitor of NADPH oxidase, exhibits anti‐inflammatory properties in ulcerative colitis. However, the underlying mechanism by which apocynin exerts this effect has not been clearly demonstrated. The objective of this study was to elucidate the anti‐inflammatory mechanism of apocynin in lipopolysaccharide (LPS)‐challenged RAW264.7 macrophage cells. Apocynin inhibited LPS‐induced extracellular secretion of the pro‐inflammatory mediators, nitric oxide (NO) and PGE2 and the expression of inducible nitric oxide synthase and cyclooxygenase‐2. Apocynin also suppressed LPS‐induced secretion of the pro‐inflammatory cytokine, tumor necrosis factor‐α and LPS‐induced degradation of IκB, which retains NF‐κB in the cytoplasm, consequently inhibiting the transcription of pro‐inflammatory genes by NF‐κB in the nucleus. To elucidate the underlying anti‐inflammatory mechanism of apocynin, the involvement of the mitogen‐activated protein (MAP) kinases, c‐jun N‐terminal kinase, extracellular signal‐regulated kinases, and p38 was examined. Apocynin attenuated LPS‐induced activation of all three MAP kinases in a concentration‐dependent manner. The present study demonstrates apocynin exerts anti‐inflammatory activity via the suppression of MAP kinase signaling pathways in LPS‐challenged RAW264.7 macrophage cells. Drug Dev Res, 2016.

Electron microscopic study of intercellular space: Correlation analysis of bronchial asthma and gastroesophageal reflux disease

Background and Aims:  Bronchial asthma (BA) is considered an extra‐esophageal syndrome of gastroesophageal reflux disease (GERD) with poor pathophysiological background. We analyzed the correlation between GERD and BA, examining esophageal epithelium with transmission electron microscopy (TEM), along with clinical findings.

Occult gastric cancer with distant metastasis proven by random gastric biopsy

Krukenberg tumor, a rare metastatic ovarian tumor arising from gastrointestinal adenocarcinoma mainly, tends to occur in premenopausal females. Finding the origin of a Krukenberg tumor is crucial for determining prognosis. In Eastern countries, the most common origin of Krukenberg tumor is stomach cancer, which is generally diagnosed via endoscopic biopsy to investigate an abnormal mucosal lesion. Here, we describe a case of huge adnexal mass in a 33-year-old woman who presented with abdominal distension. Two independent endoscopic examinations performed by experts in two tertiary university hospitals revealed no abnormal mucosal lesion. The patient was diagnosed with a Krukenberg tumor according to findings from random endoscopic biopsies taken from normal-looking gastric mucosa in our hospital. It is very rare to be diagnosed via a random biopsy in cases where three well-trained endoscopists had not found any mucosal lesion previously. Thus, in this case, random biopsy was helpful in finding the origin of a Krukenberg tumor.

Expression of Heat Shock Proteins and Cytokines in Response to Ethanol Induced Damage in the Small Intestine of ICR Mice.

BACKGROUND/AIMS Ethanol administration causes intestinal epithelial cell damage by increasing intestinal permeability and the translocation of endotoxins from intestinal bacterial flora. Heat shock proteins (HSPs) are associated with recovery and protection from cell damage. The aim of the current study was to investigate differences in the expression of HSPs in the small intestine and the biochemical changes attributable to ethanol-induced intestinal damage. METHODS Ethanol (20%) was injected intraperitoneally (2.75 g/kg, 5.5 g/kg, 8.25 g/kg) in ICR mice and the same volume of saline was administered to controls. After 1 hour, the proximal, middle, and distal segments were taken from the small intestine and the degree of damage was analyzed. In each segment, the expression of HSPs was analyzed by western blotting. The expression of inflammatory mediators including interleukin-1β (IL-1β), tumor necrosis factor-α (TNF-α), cyclooxygenase-2 (COX-2), and antioxidant enzyme such as glutathione-S-transferase were compared using real-time polymerase chain reaction assays. RESULTS In the control group, HSP70 increased in all segments of small intestine. Additionally, increases in the expression of HSP40 and HSP90 in the distal regions and an increase in HSP32 in the middle regions were observed. After ethanol treatment, greater histological damage was observed in the distal small intestine and significant decreases in HSPs were observed generally. Increased expression of IL-1β, TNF-α, and COX-2 was observed in small intestinal tissues exposed to ethanol-induced damage. However, there was no significant difference in the expression of an antioxidant enzyme. CONCLUSIONS Significant differences in the expression of HSPs in different intestinal regions were observed. These differences may have been attributable to the distribution of intestinal bacteria.

Evaluation of the Efficacy and Safety of DA-9601 versus Its New Formulation, DA-5204, in Patients with Gastritis: Phase III, Randomized, Double-Blind, Non-Inferiority Study

This study compared the efficacy of DA-9601 (Dong-A ST Co., Seoul, Korea) and its new formulation, DA-5204 (Dong-A ST Co.), for treating erosive gastritis. This phase III, randomized, multicenter, double-blind, non-inferiority trial randomly assigned 434 patients with endoscopically proven gastric mucosal erosions into two groups: DA-9601 3 times daily or DA-5,204 twice daily for 2 weeks. The final analysis included 421 patients (DA-5204, 209; DA-9601, 212). The primary endpoint (rate of effective gastric erosion healing) and secondary endpoints (cure rate of endoscopic erosion and gastrointestinal [GI] symptom relief) were assessed using endoscopy after the treatment. Drug-related adverse events (AEs), including GI symptoms, were also compared. At week 2, gastric healing rates with DA-5204 and DA-9601 were 42.1% (88/209) and 42.5% (90/212), respectively. The difference between the groups was −0.4% (95% confidence interval, −9.8% to 9.1%), which was above the non-inferiority margin of −14%. The cure rate of gastric erosion in both groups was 37.3%. The improvement rates of GI symptoms with DA-5204 and DA-9601 were 40.4% and 40.8%, respectively. There were no statistically significant differences between the two groups in both secondary endpoints. AEs were reported in 18 (8.4%) patients in the DA-5204 group and 19 (8.8%) in the DA-9601 group. Rates of AE were not different between the two groups. No serious AE or adverse drug reaction (ADR) occurred. These results demonstrate the non-inferiority of DA-5204 compared to DA-9601. DA-5204 is as effective as DA-9601 in the treatment of erosive gastritis. Registered randomized clinical trial at ClinicalTrials.gov (NCT02282670)

Extraesophageal Manifestations of Gastroesophageal Reflux Disease

Gastroesophageal reflux disease (GERD) is a common disease, affecting approx 40 million people in the United States alone. In fact, even this huge number is only an estimate, which is based on population surveys of the prevalence of frequent heartburn (the cardinal symptom of GERD) in the population. The GERD population would likely be even larger if the estimate encompassed individuals with extraesophageal manifestations of GERD, as well as heartburn sufferers. Extraesophageal manifestations of GERD, encompassing a spectrum of pulmonary and otolaryngologic disorders, may be the primary (or only) manifestation of GERD in some individuals. The implicated syndromes include posterior laryngitis, asthma, chronic cough, recurrent pneumonitis, chronic hoarseness, chest pain, pharyngitis, sinusitis, and dental disease.

Angiolipoma of the stomach presenting with anaemia

Angiolipoma is a morphological variation of the lipoma and is a benign tumour that consists of mature adipose tissue and proliferating blood vessels. It occurs very rarely in the digestive tract, especially the stomach. We report a gastric angiolipoma in a 58-year-old woman admitted for anaemia and melena. Endoscopy showed a large polypoid mass with superficial ulceration in the anterior wall of the gastric antrum. Endoscopic ultrasound showed an about 2 cm sized isoechoic lesion at the third echo layer, with the echogenic portion on the luminal side of the lesion. Laparoscopic wedge resection was performed and histological examination showed that the lesion had encapsulated adipose tissue at the submucosal layer and stromal fibrosis just below superficial ulceration. There were blood vessels with thick walls among the mature fat cells. Therefore, the lesion was diagnosed as an angiolipoma.