Jung Oh Kim

Melatonin prevents cisplatin-induced primordial follicle loss via suppression of PTEN/AKT/FOXO3a pathway activation in the mouse ovary

Premature ovarian failure (POF) is a major side effect of chemotherapy in young cancer patients. To develop pharmaceutical agents for preserving fertility, it is necessary to understand the mechanisms responsible for chemotherapy‐induced follicle loss. Here, we show that treatment with cisplatin, a widely used anticancer drug, depleted the dormant follicle pool in mouse ovaries by excessive activation of the primordial follicles, without inducing follicular apoptosis. Moreover, we show that co‐treatment with the antioxidant melatonin prevented cisplatin‐induced disruption of the follicle reserve. We quantified the various stages of growing follicles, including primordial, primary, secondary, and antral, to demonstrate that cisplatin treatment alone significantly decreased, whereas melatonin co‐treatment preserved, the number of primordial follicles in the ovary. Importantly, analysis of the PTEN/AKT/FOXO3a pathway demonstrated that melatonin significantly decreased the cisplatin‐mediated inhibitory phosphorylation of PTEN, a key negative regulator of dormant follicle activation. Moreover, melatonin prevented the cisplatin‐induced activating phosphorylation of AKT, GSK3β, and FOXO3a, all of which trigger follicle activation. Additionally, we show that melatonin inhibited the cisplatin‐induced inhibitory phosphorylation and nuclear export of FOXO3a, which is required in the nucleus to maintain dormancy of the primordial follicles. These findings demonstrate that melatonin attenuates cisplatin‐induced follicle loss by preventing the phosphorylation of PTEN/AKT/FOXO3a pathway members; thus, melatonin is a potential therapeutic agent for ovarian protection and fertility preservation during chemotherapy in female cancer patients.

3’-UTR Polymorphisms in the MiRNA Machinery Genes DROSHA, DICER1, RAN, and XPO5 Are Associated with Colorectal Cancer Risk in a Korean Population

MicroRNAs play an important role in cancer initiation and development. The aim of this study was to investigate whether polymorphisms in miRNA machinery genes are associated with the development of colorectal cancer (CRC). RAN rs14035 CT heterozygotes and T allele carriers (CT + TT) genotypes had lower risk of CRC, while the DICER1 rs3742330, DROSHA rs10719, and XPO5 rs11077 polymorphisms were not associated with CRC in the full study sample. Specifically, male RAN rs14035 CT heterozygotes and XPO5 rs11077 AA genotype (CT/AA) carriers experienced reduced CRC susceptibility (both colon and rectal). Subgroup analysis demonstrated that the combined RAN rs14035 CT + TT genotype was associated with rectal cancer, but not colon cancer. In addition, the DICER1 rs3742330 AG genotype was associated with a significantly increased risk of colon cancer. Stratified analysis revealed the RAN rs14035 combined CT+TT genotype was associated with decreased CRC risk in male patients without diabetes mellitus (DM) and in patients with rectal cancer. In addition, we found the RAN rs14035 CC genotype was related to a decreased risk of CRC with respect to tumor size and metabolism of homocysteine and folate. Furthermore, patients diagnosed with hypertension or DM who carried the DROSHA rs10719 CC genotype showed increased CRC risk, while the XPO5 rs11077 AC+CC genotype led to increased CRC risk in patients with hypertension only. Our results indicate variations in RAN rs14035, DICER1 rs3742330, XPO5 rs11077, and DROSHA rs10719 of Korean patients are significantly associated with their risk of CRC.

Association of the Single Nucleotide Polymorphisms in microRNAs 130b, 200b, and 495 with Ischemic Stroke Susceptibility and Post-Stroke Mortality.

The microRNA (miRNA) is a small non-coding RNA molecule that modulates gene expression at the posttranscriptional level. Platelets have a crucial role in both hemostasis and thrombosis, a condition that can occlude a cerebral artery and cause ischemic stroke. miR-130b, miR-200b, and miR-495 are potential genetic modulators involving platelet production and activation. We hypothesized that single nucleotide polymorphisms (SNPs) in these miRNAs might potentially contribute to the susceptibility to ischemic stroke and post-stroke mortality. This study included 523 ischemic stroke patients and 400 control subjects. We investigated the association of three miRNA SNPs (miR-130bT>C, miR-200bT>C, and miR-495A>C) with ischemic stroke prevalence and post-stroke mortality. In the multivariate logistic regression, there was no statistically significant difference in the distribution of miR-130bT>C, miR-200bT>C, or miR-495A>C between the ischemic stroke and control groups. In the subgroup analysis based on ischemic stroke subtype, the miR-200b CC genotype was less frequently found in the large-artery atherosclerosis stroke subtype compared with controls (TT+CT vs CC; adjusted odds ratio for CC, 0.506; 95% confidence interval, 0.265–0.965). During a mean follow-up period of 4.80 ± 2.11 years after stroke onset, there were 106 all-cause deaths among the 523 stroke patients. Multivariate Cox regression analysis did not find a significant association between post-stroke mortality and three miRNA SNPs. Our findings suggest that the functional SNP of miR-200b might be responsible for the susceptibility to large-artery atherosclerotic stroke.

Genetic variants of vascular endothelial growth factor are associated with recurrent implantation failure in Korean women

Vascular endothelial growth factor (VEGF) is involved in embryonic development, decidual vascularization and placenta angiogenesis. This study was performed to determine whether there is an association between genetic polymorphisms in the VEGF gene and the development of recurrent implantation failure (RIF) in Korean women. A total of 119 women diagnosed with RIF and 236 control subjects were genotyped for VEGF polymorphic sites including rs833061 (-460T>C), rs25648 (-7C>T) and rs3025020 (-583C>T) using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) assays and real-time PCR. The VEGF rs833061 C allele and rs25648 T allele were significantly associated with increased RIF risk (odds ratio [OR] = 1.813 [1.161-2.831], P = 0.009, OR = 2.213 [1.254-3.903], P = 0.005). The rs833061/rs25648 TC/CT, TC/CT+TT, and rs833061/rs3025020 TC+CC/TT genotypes were more frequent in the RIF group compared with the control group (OR = 2.130 [1.092-4.156], P = 0.025, OR = 2.130 [1.092-4.156], OR = 4.261 [1.163-15.620], P = 0.028, respectively). The results of this study suggests that VEGF polymorphisms are associated with RIF development. Therefore, we postulate that VEGF polymorphisms might be useful markers to predict RIF development. Further studies are warranted to elucidate the role of VEGF variants and RIF development.

Association between hepatocellular carcinoma and tumor necrosis factor alpha polymorphisms in South Korea

AIM To investigate associations between the tumor necrosis factor alpha (TNF-α) -1031 T>C, -863 C>A, -857 C>T, -308 G>A, and -238 G>A polymorphisms and HCC in Korea. METHODS Hepatocellular carcinoma (HCC) cases were diagnosed at CHA Bundang Medical Center from June 1996 to August 2008. The association between TNF-α polymorphisms and HCC was analyzed in 157 HCC patients and 201 controls using a polymerase chain reaction-restriction fragment length polymorphism assay. We investigated five TNF-α polymorphisms, which are TNF-α -1031 T>C, -863 C>A, -857 C>T, -308 G>A, and -238 G>A. The TNF-α genotype frequencies, genotype combinations and haplotypes were analyzed to disclose the association with HCC. RESULTS None of the TNF-α polymorphisms was significantly associated with HCC. However, nine genotype combinations had associations with increased likelihood of HCC. Among them, TNF-α -1031/-857/-238 TT/CC/GA (AOR = 18.849, 95%CI: 2.203-161.246, P = 0.007), TNF-α -1031/-308/-238 TT/GG/GA (AOR = 26.956, 95%CI: 3.071-236.584, P = 0.003), and TNF-α -1031/-238 TT/GA (AOR = 21.576, 95%CI: 2.581-180.394, P = 0.005) showed marked association with HCC. There were five haplotypes of TNF-α polymorphisms which were significantly associated with HCC. They are TNF-α -1031/-863/-857/-308/-238 T-C-C-G-A (OR = 25.824, 95%CI: 1.491-447.223, P = 0.0005), TNF-α -1031/-857/-308/-238 T-C-G-A (OR = 12.059, 95%CI: 2.747-52.950, P < 0.0001), TNF-α -1031/-857/-238 T-C-A (OR = 10.696, 95%CI: 2.428-47.110, P = 0.0001), TNF-α -1031/-308/-238 T-G-A (OR = 7.556, 95%CI: 2.173-26.280, P = 0.0002) and TNF-α -1031/-238 T-A (OR = 10.865, 95%CI: 2.473-47.740, P = 0.0001). Moreover, HCC Okuda stage III cases with the TNF-α -1031 CC genotype had better survival than those with the TT genotype (AOR = 5.795, 95%CI: 1.145-29.323). CONCLUSION Although no single TNF-α polymorphism is associated with HCC in this study, some TNF-α genotype combinations and haplotypes are associated with HCC. In addition, HCC Okuda stage III cases with the TNF-α -1031 TT genotype may have a better prognosis than those with the CC genotype.

Genetic Variation of Methylenetetrahydrofolate Reductase (MTHFR) and Thymidylate Synthase (TS) Genes Is Associated with Idiopathic Recurrent Implantation Failure.

The one-carbon metabolism pathway disorder was important role in successful pregnancy. The MTHFR and TS protein were crucial factor in one-carbon metabolism. To investigate the association between recurrent implantation failure (RIF) and enzymes in the one-carbon metabolism pathway. A total of 120 women diagnosed with RIF and 125 control subjects were genotyped for MTHFR 677C>T, 1298A>C, TSER 2R/3R and TS 1494del/ins by a polymerase chain reaction-restriction fragment length polymorphism assay. According to the gene-gene combination analysis, the MTHFR 677/MTHFR 1298 (TT/AA) and MTHFR 677/TS 1494 (TT/6bp6bp) genetic combinations were associated with relatively higher risks [adjusted odds ratio (AOR), 2.764; 95% CI, 1.065–7.174; P = 0.037 and AOR, 3.186; 95% CI, 1.241–8.178; P = 0.016] in RIF patients compared to the CC/AA (MTHFR 677/MTHFR 1298) and TT/6bp6bp (MTHFR 677/TS 1494) combinations, respectively. The results suggested that the combined MTHFR 677/MTHFR 1298 genotype might be associated with increased risk of RIF. To the best of our knowledge, this study is the first to elucidate the potential association of MTHFR, TS and TSER polymorphisms with RIF risk in Korean patients.

Variation in the Dicer and RAN Genes Are Associated with Survival in Patients with Hepatocellular Carcinoma.

Single-nucleotide polymorphisms (SNPs) in microRNA machinery genes might affect microRNA processing and subsequently impact tumorigenesis. The aim of this study was to investigate the associations between SNPs in microRNA machinery genes and hepatocellular carcinoma (HCC) in a Korean population. Genotyping of six SNPs in microRNA machinery genes was performed using blood samples from 147 patients with HCC and 209 healthy control subjects. None of the six SNPs in microRNA machinery genes were significantly associated with HCC development. However, among the models for six polymorphic loci—DICER (rs3742330 and rs13078), DROSHA (rs10719 and rs6877842), RAN (rs14035) and XPO5 (rs11077)—one allele combination (A-A-T-C-C-C) showed synergistic effects in terms of an increased risk of HCC development (odds ratio = 8.881, 95% confidence interval [CI] = 1.889–41.750; P = 0.002). Multivariate Cox proportional hazard regression analysis showed a significant survival benefit for the DICER rs3742330 GG compared with the AA type (hazard ratio [HR], 0.314; 95% CI, 0.135–0.730; P = 0.007) and for the RAN rs14035 CT compared with the CC genotype (HR, 0.587; 95% CI, 0.349–0.987; P = 0.044). Although we found no direct association between DICER (rs3742330 and rs13078), DROSHA (rs10719 and rs6877842), RAN (rs14035) or XPO5 (rs11077) polymorphisms and HCC risk, we demonstrated that DICER (rs3742330) and RAN (rs14035) were associated with the survival of HCC patients. Future studies with larger samples are needed to determine associations of SNPs in microRNA machinery genes with HCC risk and prognosis.

Association of miR-146aC>G, miR-149C>T, miR-196a2T>C, and miR-499A>G polymorphisms with risk of recurrent implantation failure in Korean women

OBJECTIVE The aim of this study was to investigate the association of microRNA polymorphisms (miR-146aC>G, miR-149T>C, miR-196a2T>C, and miR-499A>G) in Korean patients with recurrent implantation failure (RIF). METHODS We conducted a case-control study of 354 Korean women: 120 patients with RIF and 234 healthy controls with at least one live birth and no history of pregnancy loss. RESULTS The combined miR-146aCG+GG/miR-196a2CC genotype was more frequent in patients than in controls (P<0.05), and apparently conferred increased susceptibility. Conversely, genotype-based multifactor dimensionality reduction analysis, revealed that the G-T-T-A (miR-146a/-149/-196a2/-499) and G-T-T inferred genotypes (miR-146a/-149/-196a2) were significantly less frequent in patients, which suggested potential protective effects. The expression of miR-146a for the GG homozygote was significantly lower (P<0.05) than expression of the CC homozygote from both the pre, mature and sequences of miR-146a-3p (P<0.05 each). The expression of miR-196a2 for the CC homozygote was also lower than the TT homozygote from the mature sequence of miR-196a2-3p (P<0.05). CONCLUSIONS These results suggest that the polymorphisms in miR-146a and miR-196a2 could alter their target mRNA expression. Our findings suggest that expression levels of miR-146aC>G, miR-196a2T>C and putative gene-gene interaction between miR-146a, miR-196a2, miR-149 may be involved in RIF development in Korean women.

miR-27a and miR-449b polymorphisms associated with a risk of idiopathic recurrent pregnancy loss

Objective MicroRNAs (miRNAs) regulate gene expression during the peri-implantation period. The purpose of this study was to investigate whether genetic polymorphisms in the four miRNAs associated with fetal or placental development play roles in the development of idiopathic recurrent pregnancy loss (RPL) in Korean females. Study design A case-control study involving 225 controls and 387 women with at least two consecutively recurrent pregnancy losses between 1999 and 2012 was performed. The genotypes of the four miRNA polymorphisms, including miR-27a rs895819, miR-423 rs6505162, miR-449b rs10061133, and miR-605 rs2043556, were analyzed by the polymerase chain reaction-restriction fragment length polymorphism assay. Odds ratios and 95% confidence intervals were estimated using multivariate analyses after maternal age adjustments. The relationships between each of the four microRNA genotypes and each of the six clinical parameters of the RPL patients (plasma homocysteine and folate levels, natural killer cell number, platelet count, prothrombin time, and, activated partial thromboplastin time) were analyzed using multiple linear regression analyses. Results Our results suggest that weak associations between decreased RPL risk and the genotypes of miR-27a (AG and AG+GG), combination genotype of miR-27a/miR-423 (AG/GC), and haplotypes of miR-27a/miR-423/miR-449b/miR-605 (G-C-A-G) and miR-27a/miR-449b/miR-605 (G-A-G), whereas weak associations between increased RPL risk and genotypes of miR-449b (GG and AG+GG), combination genotypes of miR-423/miR-449b (CC/GG and CA/AG), miR-449b/miR-605 (AG/AG), haplotypes of miR-27a/miR-423/miR-449b/miR-605 (A-C-G-A, A-A-A-G, and G-C-G-G), miR-27a/miR-423/miR-449b (A-C-G), miR-27a/miR-449b/miR-605 (A-A-G, A-G-A, and G-G-G), miR-423/miR-449b/miR-605 (C-G-G and A-A-G), and miR-423/miR-449b (C-G and A-A). The genotypes of miR-27a (AG and AG+GG) also showed significant contributions to the prediction of folate levels in RPL patients. Conclusions The study showed associations between miRNA polymorphisms (miR-27a rs895819 and miR-449b rs10061133) and RPL development, and between the miRNA polymorphism (miR-27a rs895819) and plasma folate levels.

Association of miR-146a, miR-149, miR-196a2, and miR-499 Polymorphisms with Ossification of the Posterior Longitudinal Ligament of the Cervical Spine

Background Ossification of the posterior longitudinal ligament (OPLL) of the spine is considered a multifactorial and polygenic disease. We aimed to investigate the association between four single nucleotide polymorphisms (SNPs) of pre-miRNAs [miR-146aC>G (rs2910164), miR-149T>C (rs2292832), miR-196a2T>C (rs11614913), and miR-499A>G (rs3746444)] and the risk of cervical OPLL in the Korean population. Methods The genotypic frequencies of these four SNPs were analyzed in 207 OPLL patients and 200 controls by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) assay. Findings For four SNPs in pre-miRNAs, no significant differences were found between OPLL patients and controls. However, subgroup analysis based on OPLL subgroup (continuous: continuous type plus mixed type, segmental: segmental and localized type) showed that miR-499GG genotype was associated with an increased risk of segmental type OPLL (adjusted odds ratio = 4.314 with 95% confidence interval: 1.109–16.78). In addition, some allele combinations (C-T-T-G, G-T-T-A, and G-T-C-G of miR-146a/-149/-196a2/-499) and combined genotypes (miR-149TC/miR-196a2TT) were associated with increased OPLL risk, whereas the G-T-T-G and G-C-C-G allele combinations were associated with decreased OPLL risk. Conclusion The results indicate that GG genotype of miR-499 is associated with significantly higher risks of OPLL in the segmental OPLL group. The miR-146a/-149/-196a2/-499 allele combinations may be a genetic risk factor for cervical OPLL in the Korean population.