Hee Nam Kim

Association between folate-metabolizing pathway polymorphism and non-Hodgkin lymphoma

Polymorphisms in the genes coding folate‐metabolizing enzymes affect the risk of some forms of cancer. We investigated the association between these polymorphisms and non‐Hodgkin lymphoma (NHL) risk in a population‐based study (583 cases and 1700 controls). The MTHFR 677TT and CT genotypes were associated with reduced risk for NHL [odds ratios (OR) = 0·79; 95% confidence intervals (CI) = 0·65–0·98 for 677CT and 0·61; 0·45–0·82 for 677TT] and diffuse large B‐cell lymphoma (DLBCL) (OR = 0·68; 0·51–0·88 for 677CT; OR = 0·56; 0·38–0·83 for 677TT). The MTHFR 1298CC genotype was associated with increased risk for NHL (OR = 1·71; 1·07–2·75) and T‐cell lymphoma (OR = 3·05; 1·53‐6·11). The MTRR 66GG genotype was associated with increased risk for DLBCL (OR = 1·56; 1·03‐2·38) and the TYMS 2R2R genotype was associated with increased risk for T‐cell lymphoma (OR = 2·83; 1·33–6·01). Using subjects with 3RG3RG as a reference group, TYMS 2R2R was associated with increased risk for T‐cell lymphoma (OR = 2·46; 1·04–5·79). Interestingly, we observed a reduced association between the TYMS 2R3RG genotype and DLBCL (OR = 0·61; 0·38–0·99). These results suggest that MTHFR, MTRR and TYMS polymorphisms may play a significant role in the risk for NHL.

Association between polymorphisms of folate-metabolizing enzymes and hematological malignancies

Several genetic polymorphisms in the genes coding folate-metabolizing enzymes have been associated with susceptibility to hematology malignancies. We conducted a Korean population-based case-control study to examine the relationship between the polymorphisms of folate-metabolizing enzymes and the risk of AML (acute myelogenous leukemia), CML (chronic myelogenous leukemia), MDS (myelodyspastic syndrome), and ALL (acute lymphoblastc leukemia). The MTHFR 677TT genotype was associated with an increased risk for ALL (odds ratios (OR)=1.77; 95% confidence intervals (CI)=1.02-3.09, p=.044). The MTRR 66 AG genotype was associated with an increased risk for MDS (OR=1.59; 1.06-2.38, p=.026) and the MTRR 66 GG genotype was associated with increased risk for AML (OR=1.51; 1.03-2.23, p=.037). The TYMS 2R3R genotype was associated with a decreased risk for AML (OR=0.76; 0.60-0.96, p=.022). The TYMS hap3 (2R-6bp) and hap4 (2R-0bp) were associated with decreased risk (OR=0.69; 0.53-0.90, p=.006) and increased risk (OR=1.65; 1.20-2.27, p=.002), respectively for AML. Hap C (677T-1298A) was associated with an increased risk (OR=1.40; 1.02-1.92, p=.04) for ALL. The risk for ALL appears to be associated with the MTHFR 677 polymorphism. The results are supportive of a risk modification by folate polymorphisms in several hematologic malignancies in Korea. The pattern of results suggests that MDS was associated with the DNA methylation status and the risk for AML was associated with both the DNA synthesis and DNA methylation status.

Design of novel analogue peptides with potent antibiotic activity based on the antimicrobial peptide, HP (2–20), derived from N-terminus of Helicobacter pylori ribosomal protein L1

HP (2-20) (AKKVFKRLEKLFSKIQNDK) is the antimicrobial sequence derived from the N-terminus of Helicobacter pylori ribosomal protein L1 (RPL1). In order to develop novel antibiotic peptides useful as therapeutic agents, potent antibiotic activities against bacteria, fungi and cancer cells without a cytotoxic effect are essential. To this end, several analogues with amino acid substitutions were designed to increase or decrease only the net hydrophobicity. In particular, the substitution of Trp for the hydrophobic amino acids, Gln and Asp at positions 17 and 19 of HP (2-20) (Anal 3), caused a dramatic increase in antibiotic activity without a hemolytic effect. In contrast, the decrease of hydrophobicity brought about by substituting Ser for Leu and Phe at positions 12 and 19 of HP (2-20), respectively (Anal 4, Anal 5), did not have a significant effect on the antibiotic activity. The antibiotic effects of these synthetic peptides were further investigated by treating prepared protoplasts of Candida albicans and conducting an artificial liposomal vesicle (PC/PS; 3:1, w/w) disrupting activity test. The results demonstrated that the Anal 3 prevented the regeneration of fungal cell walls and induced an enhanced release of fluorescent dye (carboxyfluorescein) trapped in the artificial membrane vesicles to a greater degree than HP (2-20). The potassium-release test conducted on C. albicans indicated that Anal 3 induced greater amounts of potassium ion to be released than the parent peptide, HP (2-20) did. These results indicated that the hydrophobic region of peptides is prerequisite for its effective antibiotic activity and may facilitate easy penetration of the lipid bilayers of the cell membrane.

BRCA1 and XRCC1 polymorphisms associated with survival in advanced gastric cancer treated with taxane and cisplatin

This study evaluated the influence of genetic polymorphism influencing drug metabolism on survival in taxane‐ and cisplatin‐treated advanced gastric cancer (AGC). Peripheral blood samples from 207 AGC patients treated with first‐line chemotherapy of taxane and cisplatin were used. We investigated polymorphisms that influenced the metabolism of taxane (ATP‐binding cassette transporter B1 (ABCB1)), cisplatin (glutathione S‐transferase M1 (GSTM1), glutathione S‐transferase P1 (GSTP1), glutathione S‐transferase T1 (GSTT1), excision repair cross complementing 1 (ERCC1), X‐ray Cross Complementing group 3 (XRCC3), X‐ray Cross Complementing group 4 (XRCC4), X‐ray Cross Complementing group 1 (XRCC1), breast cancer (BRCA1)), and 5‐fluorouracil (methylene tetrahydrofolate reductase (MTHFR), thymidylate synthase (TYMS)). A total of 207 patients were enrolled between May 2004 and Dec 2008, and 200 patients were analyzed. The overall response rate was 38.5%. Time to progression and overall survival time were 4.3 ± 0.19 months and 11.9 ± 1.05 months, respectively. There was no significant association between genetic polymorphism and response rate. However, the BRCA1 mutant TT homozygote was associated with significant prolongation of overall survival (hazard ratio [HR] = 0.43; 95% confidence interval [CI], 0.20–0.92; P = 0.03) and progression‐free survival (HR = 0.51; 95% CI, 0.26–1.00; P = 0.05). Also, the XRCC1 194 CT genotype was associated with inferior overall survival, relative to the XRCC1 194 CC homozygotes (HR = 1.49; 95% CI, 0.11–2.07; P = 0.018).These findings suggest that BRCA1 TT and XRCC1 194 CT genotypes could be modest prognostic markers of AGC response in taxane‐ and cisplatin‐treated patients.

Methylenetetrahydrofolate reductase C677T polymorphism in patients with gastric and colorectal cancer in a Korean population

BackgroundThis study was designed to investigate an association between the methylenetetrahydrofolate reductase (MTHFR) C677T polymorphism and the risk of gastric and colorectal cancer in the Korean population.MethodsWe conducted a population-based large-scale case-control study involving 2,213 patients with newly diagnosed gastric cancer, 1,829 patients with newly diagnosed colorectal cancer, and 1,700 healthy controls. Genotyping was performed with peripheral blood DNA for MTHFR C677T polymorphisms. The statistical significance was estimated by logistic regression analysis.ResultsThe MTHFR C677T frequencies of CC, CT, and TT genotypes were 35.2%, 47.5%, and 17.3% among stomach cancer, 34%, 50.5%, and 15.5% in colorectal cancer, and 31.8%, 50.7%, and 17.5% in the controls, respectively. The MTHFR 677TT genotype showed a weak opposite association with colorectal cancer compared to the homozygous CC genotype [adjusted age and sex odds ratio (OR) = 0.792, 95% confidence interval (CI) = 0.638-0.984, P = 0.035]. Subjects with the MTHFR 677CT showed a significantly reduced risk of gastric cancer compared whose with the 677CC genotype (age- and sex-adjusted OR = 0.810; 95% CI = 0.696-0.942, P = 0.006). We also observed no significant interactions between the MTHFR C677T polymorphism and smoking or drinking in the risk of gastric and colorectal cancer.ConclusionsThe T allele was found to provide a weak protective association with gastric cancer and colorectal cancer.

Association of a common genetic variant in prostate stem‐cell antigen with gastric cancer susceptibility in a Korean population

A recent genome wide association study (GWAS) indentified a significant association between rs2294008 (C > T) polymorphism in prostate stem‐cell antigen (PSCA) and increased risk of gastric cancer in Japanese and Korean populations. The aim of this study was to determine whether rs2294008 polymorphism is associated with risk of gastric cancer in a Korean population. We conducted a large‐scale case–control study of 3,245 gastric cancer patients and 1,700 controls. The frequencies of the CC, CT, and TT genotypes of rs2294008 polymorphism were 17.8%, 49.9%, and 32.3% in the gastric cancer patients; and 24.4%, 48.1%, and 27.5% in the controls, respectively. We found that the CT and TT genotypes were associated with a significantly increased risk of gastric cancer (ORCT = 1.50, 95% confidence intervals, 95% CI: 1.28–1.76; ORTT = 1.71, 95% CI: 1.43–2.04), compared with the CC genotype. Further, stratified by tumor location and histological type, the effect of the rs2294008 T allele was larger in cardia (ORTT = 2.62, 95% CI = 1.42–4.85) than non‐cardia (ORTT = 1.67, 95% CI = 1.40–2.00), in diffuse‐type (ORTT = 2.00, 95% CI: 1.55–2.59) than in intestinal‐type (ORTT = 1.51, 95% CI: 1.22–1.86). Our study showed that rs2294008 in the PSCA gene was associated with increased risks of gastric cancer in a Korean population, suggests that rs2294008 might play an important role in gastric carcinogenesis.

Influence of polymorphisms in MTHFR 677 C→T, TYMS 3R→2R and MTR 2756 A→G on NSCLC risk and response to platinum-based chemotherapy in advanced NSCLC

AIMS Genetic factors may contribute to individual differences in cancer susceptibility, drug efficacy and toxicity. This study was designed to investigate the effects of the polymorphisms of methylenetetrahydrofolate reductase 677 C→T (MTHFR 677 C→T), thymidylate synthase (TYMS 3R→2R),and methionine synthase 2756 A→G (MTR 2756 A→G) on the risk of lung cancer and response to platinum-based chemotherapy in advanced non-small-cell lung cancer (NSCLC). MATERIALS & METHODS We conducted a case-control study involving 438 NSCLC cases (including 101 follow-up cases) and 641 healthy controls in North China. RESULTS & CONCLUSION Using a genetic model analysis, the polymorphism MTHFR 677 C→T showed a significantly increased risk for NSCLC in women but not in men, which was observed in the codominant model (CT vs CC adjusted odds ratio [OR] = 2.46; 95% confidence interval [CI]: 1.37-4.42; p = 0.003; TT vs CC adjusted OR: 2.04; 95% CI: 1.09-3.81; p = 0.03) and the dominant model (CT + TT vs CC adjusted OR: 2.30; 95% CI: 1.31-4.05; p = 0.004). In addition, we found that patients with the MTHFR 677 TT genotype showed a better response to platinum-based chemotherapy in the recessive model (TT vs CT + CC adjusted OR: 0.24; 95% CI: 0.09-0.68; p = 0.007), the generalized OR was 0.44 (0.22-0.88; p = 0.04). There were no significant associations of the polymorphisms of TYMS 3R→2R or MTR 2756 A→G with the risk of NSCLC or response to platinum-based chemotherapy in advanced NSCLC in any genetic model. Our results suggest that genetic polymorphisms of MTHFR 677 C→T may contribute to NSCLC development in Chinese women and could also influence treatment response for advanced NSCLC patients with platinum-based chemotherapy. Further studies with larger sample sizes are required to validate this association.

p53 codon 72 polymorphism and the risk of lung cancer in a Korean population.

The aim of this study was to assess whether p53 codon 72 polymorphism is associated with an increased risk of lung cancer (LC) in a South Korean population. We conducted a population-based, large-scale, case-control study including 3939 patients with LC and 1700 controls. P53 codon 72 polymorphism was determined by real-time polymerase chain reaction (PCR). The frequencies of p53 codon 72 polymorphisms (Arg/Arg, Arg/Pro, and Pro/Pro) in LC were 37.0%, 46.2%, and 16.7%, respectively; frequencies in the controls were 43.2%, 45.6%, and 11.2%, respectively (p<0.01). The Arg/Pro and Pro/Pro genotype were significantly associated with increased risk of LC (odds ratio (OR)=1.22, 95% confidence interval (CI)=1.06-1.14 and OR=1.83, 95% CI=1.48-2.26, respectively) compared with the Arg/Arg genotype. Risk was compared in different subgroups. The OR of Pro/Pro genotype was significantly higher in small cell lung cancer (SCC) and squamous cell carcinoma (SQC) than in adenocarcinoma (ADC). Higher OR of Pro/Pro genotype was also seen among males. However, relationships between gender, age, smoking, and genotypes were not found. P53 codon 72 polymorphism was associated with an increased risk of LC in this Korean population; the association was especially noteworthy in SQC, SCC, and males.

The Effect of Apolipoprotein E Polymorphism on Lipid Levels in Korean Adults

The aim of this study was to determine the effects of polymorphisms in the apolipoprotein E gene (APOE) on lipid levels in Korean adults and to investigate the interactions between these polymorphisms and environmental factors in determining lipid levels. We performed a cross-sectional study of 1,900 subjects (668 men and 1,232 women; 45-74 yr old) in Namwon, Korea, in 2004. APOE polymorphisms were determined by polymerase chain reaction and restriction enzyme analysis. Carriers of the APOE*E2 (E2) allele had significantly lower total cholesterol and low-density lipoprotein cholesterol (LDL-C) concentrations than did carriers of the APOE*E3 (E3) or APOE*E4 (E4) alleles, regardless of gender. The APOE allele type had significant effect on high-density lipoprotein cholesterol (HDL-C) and triglyceride levels in women, but not in men. The effect of APOE allele type on HDL-C levels was modified by age in women. In addition, in men, the effect of APOE allele type on triglyceride levels was modified by smoking. These findings highlight the important effect of gene-environment interactions on lipid levels.

Antimicrobial mechanism of β-glycyrrhetinic acid isolated from licorice, Glycyrrhiza glabra

Abstractβ-Glycyrrhetinic acid isolated from Glycyrrhiza glabra had an antibacterial activity of 7.6 and 12.5 μg ml−1 against Bacillus subtilis and Staphylococcus epidermidis without causing hemolysis of human erythrocytes, whereas it was not inhibitory against Escherichia coli, Proteus vulgaris and various fungi. Confocal microscopy showed that β-glycyrrhetinic acid was located within the bacteria but had not caused membrane disruption. It then inhibited synthesis of DNA, RNA and protein.