• Journal of Gastric Cancer
• /
• v.15 no.3
• /
• pp.201-208
• /
• 2015

Purpose: The AT-rich interactive domain 1A (ARID1A ) gene encodes BRG1-associated factor 250a, a component of the SWItch/Sucrose NonFermentable chromatin remodeling complex, which is considered a tumor suppressor in many tumors. We aimed to investigate the prognostic significance of ARID1A expression in gastric cancers and explore its relationship with clinicopathologic parameters such as mismatch repair protein expression. Materials and Methods: Four tissue microarrays were constructed from 191 resected specimens obtained at Soonchunhyang University Cheonan Hospital from 2006 to 2008. Nuclear expression of ARID1A was semiquantitatively assessed and binarized into retained and lost expression. Results: Loss of ARID1A expression was observed in 62 cases (32.5%). This was associated with more frequent vascular invasion (P=0.019) and location in the upper third of the stomach (P=0.001), and trended toward more poorly differentiated subtypes (P=0.054). ARID1A loss was significantly associated with the mismatch repair-deficient phenotype (P=0.003). ARID1A loss showed a statistically significant correlation with loss of MLH1 (P=0.001) but not MSH2 expression (P=1.000). Kaplan-Meier survival analysis showed no statistically significant difference in overall survival; however, patients with retained ARID1A expression tended to have better overall survival than those with loss of ARID1A expression (P=0.053). In both mismatch repair-deficient and mismatch repair-proficient groups, survival analysis showed no differences related to ARID1A expression status. Conclusions: Our results demonstrated that loss of ARID1A expression is closely associated with the mismatch repair-deficient phenotype, especially in sporadic microsatellite instability-high gastric cancers.

• Proceedings of the Korea Crystallographic Association Conference
• /
• 2003.05a
• /
• pp.16-16
• /
• 2003

Mismatches in a DNA duplex are mainly due to DNA duplication errors that are generated by improper function of DNA polymerase. MutS, MutL and MutH are crucial proteins for the initiation of the methyl-directed mismatch repairing in bacteria. MutS has an ATPase activity md recognize the mismatched or unpaired bases on DNA. After binding to a mismatch, MutS recruits MutL to mediate the activation of MutH an endonuclease, which cleaves the 5' site of d(GATC) on the un-methylated strand. Both MutL and MutS also have essential roles in the subsequent removal and re-synthesis of the daughter strand. We have determined the crystal structures of either intact or active fragments of each of these proteins, both alone and complexed with ligands (DNA, ADP and ATP). The biochemical and mutagenesis studies based on the detailed 3-D structures led to new insights into the role of the ATPase activity of MutS in the mismatch recognition and directions for future investigation of mismatch repair.

• Molecules and Cells
• /
• v.38 no.1
• /
• pp.33-39
• /
• 2015

The correction of disease-causing mutations by single-strand oligonucleotide-templated DNA repair (ssOR) is an attractive approach to gene therapy, but major improvements in ssOR efficiency and consistency are needed. The mechanism of ssOR is poorly understood but may involve annealing of oligonucleotides to transiently exposed single-stranded regions in the target duplex. In bacteria and yeast it has been shown that ssOR is promoted by expression of $Red{\beta}$, a single-strand DNA annealing protein from bacteriophage lambda. Here we show that $Red{\beta}$ expression is well tolerated in a human cell line where it consistently promotes ssOR. By use of short interfering RNA, we also show that ssOR is stimulated by the transient depletion of the endogenous DNA mismatch repair protein MSH2. Furthermore, we find that the effects of $Red{\beta}$ expression and MSH2 depletion on ssOR can be combined with a degree of cooperativity. These results suggest that oligonucleotide annealing and mismatch recognition are distinct but interdependent events in ssOR that can be usefully modulated in gene correction strategies.

• Transactions of the Korean Society of Automotive Engineers
• /
• v.18 no.1
• /
• pp.99-104
• /
• 2010

It is a frequent occurrence in urban traffic - a low-speed collision in which one vehicle hits the back of another. The vehicles often sustain expensive damage. Bumpers can reduce this damage, but only line up so the initial contact in an impact is bumper to bumper. Then the bumpers on the colliding vehicles have to absorb the crash energy, keeping damage away from expensive sheet metal, lights, and other components. In real world accidents, Bumper mismatches in crashes are increasing, and the resulting repair costs from low-speed collisions are escalating. In this study, we investigated the bumper rail height and analyzed their effects on repair cost. Futhermore, Our 16kph front-into-rear crash tests demonstrates bumper mismatch problem.

• Asian Pacific Journal of Cancer Prevention
• /
• v.13 no.12
• /
• pp.6055-6057
• /
• 2012

The mismatch repair system (MMR) is a post-replicative DNA repair mechanism whose defects can lead to cancer. The MSH3 protein is an essential component of the system. We postulated that MSH3 gene polymorphisms might therefore be associated with prostate cancer (PC). We studied MSH3 codon 222 and MSH3 codon 1036 polymorphisms in a group of Iranian sporadic PC patients. A total of 60 controls and 18 patients were assessed using the polymerase chain reaction and single strand conformational polymorphism. For comparing the genotype frequencies of patients and controls the chi-square test was applied. The obtained result indicated that there was significantly association between G/A genotype of MSH3 codon 222 and G/G genotype of MSH3 codon 1036 with an increased PC risk (P=0.012 and P=0.02 respectively). Our results demonstrated that MSH3 codon 222 and MSH3 codon 1036 polymorphisms may be risk factors for sporadic prostate cancer in the Iranian population.

• Journal of Animal Reproduction and Biotechnology
• /
• v.36 no.3
• /
• pp.121-128
• /
• 2021

Increasing the efficiency of HR (homologous recombination) is important for a successful knock-in. Rad51 is mainly involved in homologous recombination and is associated with strand invasion. The HR-related mismatch repair system maintains HR fidelity by heteroduplex rejection and repair. Therefore, the purpose of this study is to control Rad51, which plays a critical role in HR, through UV-induced DNA damage. It is also to confirm the effect on the expression of MMR related genes (Msh2, Msh3, Msh6, Mlh1, Pms2) and HR-related genes closely related to HR through treatment with the MMR inhibitor CdCl₂. The mRNA expression of Rad51 gene was confirmed in both HC11 cells and mouse testes, but the mRNA expression of Dmc1 gene was confirmed only in mouse testes. The protein expression of Rad51 and Dmc1 gene increased in UV-irradiated HC11 cells. After 72 hours of treatment with 1 ㎛ of CdCl₂, the mRNA expression level of Msh3, Pms2, and Rad51 decreased, but the mRNA expression level of Msh6 and Mlh1 increased in HC11 cells. There was no significant difference in Msh2 mRNA expression between CdCl₂ untreated-group and the 72 hours treated group. In conclusion, HR-related gene (Rad51) was increased by UV-induced DNA damage. Treatment of the MMR inhibitor CdCl₂ in HC11 cells decreased the mRNA expression of Rad51.

• Asian Pacific Journal of Cancer Prevention
• /
• v.17 no.5
• /
• pp.2587-2592
• /
• 2016

Background: Early onset sporadic colorectal cancer (CRC) is a biologically and clinically distinct entity hypothesized to exhibit differences in histological features and microsatellite instability (MSI) as compared to typical onset CRC. This study compared the MSI status, mismatch repair enzyme deficiency and clinicopathological features of early onset (aged ${\leq}45$ years) with controls (>45 years). Materials and Methods: A total of 30 cases and 30 controls were analyzed for MSI status using the Bethesda marker panel. Using antibodies against hMLH1, hMSH2 and hMSH6, mismatch repair protein expression was assessed by immunohistochemistry. Molecular characteristics were correlated with clinicopathological features. Results: The early onset sporadic CRCs were significantly more poorly differentiated tumors, with higher N2 nodal involvement and greater frequency of signet ring phenotype than the typical onset cases. MSI was observed in 18/30 cases, with 12/18 designated as MSI-high (MSI-H) and 6/18 designated as MSI-low (MSI-L). In the control group, 14 patients exhibited MSI, with 7 MSI-H and 7 MSI-L. MSI tumors in both cases and controls exhibited loss of hMLH1, hMSH2 and hMSH6. MSS tumors did not exhibit loss of expression of MMR proteins, except hMLH1 protein in 3 controls. No statistically significant difference was noted in MSI status or expression of MMR proteins in cases versus controls. Conclusions: Microsatellite status is comparable between early and typical onset sporadic CRC patients in Pakistan suggesting that differences in clinicopathological features between these two subsets are attributable to other molecular mechanisms.

• Asian Pacific Journal of Cancer Prevention
• /
• v.15 no.7
• /
• pp.3287-3291
• /
• 2014

Background: The interesting preponderance of Chinese with colorectal carcinoma (CRC) amongst the three major ethnic groups in Malaysia prompted a study to determine DNA mismatch repair (MMR) status in our CRC and attempt correlation with patient age, gender and ethnicity as well as location, grade, histological type and stage of tumour. Histologically re-confirmed CRC, diagnosed between $1^{st} $January 2005 and $31^{st}$ December 2007 at the Department of Pathology, University of Malaya Medical Centre, were immunohistochemically stained with monoclonal antibodies to MMR proteins, MLH1, MSH2, MSH6 and PMS2 on the Ventana Benchmark XT autostainer. Of the 142 CRC cases entered into the study, there were 82 males and 60 females (M:F=1.4:1). Ethnically, 81 (57.0%) were Chinese, 32 (22.5%) Malays and 29 (20.4%) Indians. The patient ages ranged between 15-87 years (mean=62.4 years) with 21 cases <50-years and 121 ${\geq}50$-years of age. 14 (9.9%) CRC showed deficient MMR (dMMR). Concurrent loss of MLH1 and PMS2 occurred in 10, MSH2 and MSH6 in 2 with isolated loss of MSH6 in 1 and PMS2 in 1. dMMR was noted less frequently amongst the Chinese (6.2%) in comparison with their combined Malay and Indian counterparts (14.8%), and was associated with right sided and poorly differentiated tumours (p<0.05). 3 of the 5 (60.0%) dMMR CRC cases amongst the Chinese and 1 of 9 cases (11.1%) amongst the combined Malay and Indian group were <50-years of age. No significant association of dMMR was noted with patient age and gender, tumour stage or mucinous type.

• Animal Bioscience
• /
• v.35 no.1
• /
• pp.126-137
• /
• 2022

Objective: Efficient gene editing technology is critical for successful knock-in in domestic animals. RAD51 recombinase (RAD51) gene plays an important role in strand invasion during homologous recombination (HR) in mammals, and is regulated by checkpoint kinase 1 (CHK1) and CHK2 genes, which are upstream elements of RAD51 recombinase (RAD51). In addition, mismatch repair (MMR) system is inextricably linked to HR-related pathways and regulates HR via heteroduplex rejection. Thus, the aim of this study was to investigate whether clustered regularly interspaced short palindromic repeats/CRISPR-associated 9 (CRISPR/Cas9)-mediated knock-in efficiency of human lactoferrin (hLF) knock-in vector in the bovine β-casein gene locus can be increased by suppressing DNA MMR-related genes (MSH2, MSH3, MSH6, MLH1, and PMS2) and overexpressing DNA double-strand break (DSB) repair-related genes (RAD51, CHK1, CHK2). Methods: Bovine mammary epithelial (MAC-T) cells were transfected with a knock-in vector, RAD51, CHK1, or CHK2 overexpression vector and CRISPR/sgRNA expression vector to target the bovine β-casein gene locus, followed by treatment of the cells with CdCl₂ for 24 hours. After 3 days of CdCl₂ treatment, the knock-in efficiency was confirmed by polymerase chain reaction (PCR). The mRNA expression levels of DNA MMR-related and DNA DSB repair-related genes were assessed by quantitative real-time PCR (RT-qPCR). Results: Treatment with CdCl₂ decreased the mRNA expression of RAD51 and MMRrelated genes but did not increase the knock-in efficiency in MAC-T cells. Also, the overexpression of DNA DSB repair-related genes in MAC-T cells did not significantly affect the mRNA expression of MMR-related genes and failed to increase the knock-in efficiency. Conclusion: Treatment with CdCl₂ inhibited the mRNA levels of RAD51 and DNA MMR-related genes in MAC-T cells. However, the function of MMR pathway in relation to HR may differ in various cell types or species.

• IMMUNE NETWORK
• /
• v.2 no.4
• /
• pp.208-216
• /
• 2002

Background: Reactive oxygen and nitrogen are produced by rheumatoid arthritis (RA) synovial tissue and can induce mutations in key genes. Normally, this process is prevented by a DNA mismatch repair (MMR) system that maintains sequence fidelity. Key members of the MMR system include MutS${\alpha}$ (comprised of hMSH2 and hMSH6), which can sense and repair single base mismatches and 8-oxoguanine, and MutS${\beta}$ (comprised of hMSH2 and hMSH3), which repairs longer insertion/deletion loops. Methods: To provide further evidence of DNA damage, we analyzed synovial tissues for microsatellite instability (MSI). MSI was examined by PCR on genomic DNA of paired synovial tissue and peripheral blood cells (PBC) of RA patients using specific primer sequences for 5 key microsatellites. Results: Surprisingly, abundant MSI was observed in RA synovium compared with osteoarthritis (OA) tissue. Western blot analysis of the same tissues for the expression of MMR proteins demonstrated decreased hMSH6 and increased hMSH3 in RA synovium. To evaluate potential mechanisms of MMR regulation in arthritis, fibroblast-like synoviocytes (FLS) were isolated from synovial tissues and incubated with the nitric oxide donor S-nitroso-N-acetylpenicillamine (SNAP). Western blot analysis demonstrated constitutive expression of hMSH2, 3 and 6 in RA and OA FLS. When FLS were cultured with SNAP, the RA synovial pattern of MMR expression was reproduced (high hMSH3, low hMSH6). Conclusion: Therefore, oxidative stress can relax the DNA MMR system in RA by suppressing hMSH6. Decreased hMSH6 can subsequently interfere with repair of single base mutations, which is the type observed in RA. We propose that oxidative stress not only creates DNA adducts that are potentially mutagenic, but also suppresses the mechanisms that limit the DNA damage.