Distributions of MTHFR Gene Polymorphism according to the Location of Colon Cancer

PURPOSE: Colon carcinogenesis seems to vary according to the original location of tumor, especially theright and the left sides. Two common methylenetetrahydrofolate reductase (MTHFR) polymorphisms, 677C->T and 1298A->C, are now known. Especially, the TT type of the 677C->T mutation shows reduced catalytic activity at a rate 30% that of wild type. The aim of this study is to investigate the distributions of MTHFR polymorphisms of 677C->T and 1298A->C according to the location of the colon cancer. METHODS: Blood samples were collected from 112 patients diagnosed in our hospital, as having colon cancer: 34 proximal and 78 distal cases to the splenic flexure and 448 healthy control subjects. In order to characterize MTHFR polymorphisms, we applied the polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). RESULTS: The distributions of MTHFR 677C->T polymorphisms as genotypes CC, CT, and TT were 32.4%, 53.1%, and 14.5% in the control group, and 34.8%, 58.0%, and 7.1% in the cancer group (P=0.056). In the 34 proximal cancers, the CC, CT, and TT distributions were 44.1%, 55.9%, and 0% (PC polymorphism by genotypes, AA, AC, CC were 69.6%, 28.6%, and 1.8% in the control group, and 58.9%, 38.4%, and 2.7% in the cancer group. The proximal and the distal groups show genotype distributions of 44.1%, 53.0%, and 2.9% and 65.4%, 32.0%, and 2.6%, respectively, but the differences were not statistically significant. CONCLUSIONS: There are no definite differences between control subjects and colon-cancer patients in the two polymorphisms 677C->T and 1298A->C. However, the TT genotype shows a lower frequency in the cancer group than in the control group with a marginal statistical value (P=0.056), which suggest a reduced risk of cancer incidence for this type, compared with a CC or a CT type.

Discovery of Differentially Overexpressed Genes in Immortalized Cells and Human Pulmonary Non-small Cell Carcinomas

PURPOSE: Our aim of research is to find novel genes that overexpressed in various samples such as cell lines and tissues that infinitely proliferate; so-called immortalized cells, cancer cells and tissues. In this study, we obtained a gene from immortalized cell line (WI-38 VA13) then identified it from various cell lines and human lung tissues. MATERIALS AND METHODS: Using suppressive subtractive hybridization (SSH) method, we obtained many genes and selected a novel gene of them. And then the novel gene fragment was amplified by PCR and ligated in T easy vector for sequencing. And finally we found a differentially expressed gene in cell lines and tissues when it was performed by reverse transcriptase-PCR (RT-PCR). RESULTS: As the result of transformation of genes that we gained using SSH, we obtained about 150 clones. And then we certificated several genes by DNA prep and confirmed it by sequencing. We examined whether the gene sequences are novel or known genes by genome homology search and we confirmed the gene expressions by RT-PCR. As a result, we identified a differentially overexpressed gene (named "clone 58") in immortalized cells, cancer cell lines and lung squamous cell carcinomas. CONCLUSION: The "clone 58" mRNA was significantly up-regulated in various human cell lines and also human lung cancer tissues compared to the normal. We suppose that this gene can carry out a specific role related to the induction of cancer and/or the mechanism of the changeover of a normal cell to an immortalized cell. In short, the discovery of our gene has an importance in the point that they are thought to have a connection with immortalization and carcinogenesis of human cells and tissues.

Characterization of the Differentially Expressed Genes in Human Breast Cancer using Subtractive Hybridization / 한국유방암학회지

PURPOSE: Although breast cancer the most common cancer for women remains a significant health problem, it has not been systematically studied until now. In an attempt to identify novel genes implicated in breast cancer development, we performed a suppression subtraction hybridization (SSH) with human breast cancer tissues, as well as with cloned genes, that are expressed more than in normal tissue. METHODS: After the identification of a novel gene, RT-PCR was performed to determine its mRNA expression in human breast cancers. In order to learn more about the expression profile of this gene, PCR was performed using various commercially available normal or carcinoma cell lines. The novel gene was found to be strongly expressed in breast cancer tissues and other carcinoma cell lines. To determine whether this novel gene was associated with cell cycle regulation, normal WI-38 fibroblast cells were stimulated with media containing 0.1% FBS for 48hours. RESULT: From the experimental results of the SSH, a novel clone, "Clone 135" which was strongly expressed in tumor compared to matched normal tissue, has been found. The novel clone was identified as being expressed in several tumor tissues and carcinoma cell lines. The time-course expression of this novel gene in the WI-38 (8PDL) normal lung cell line indicated a significant increase for G1-phase arrest. CONCLUSION: We have used a suppression subtractive hybridization (SSH) to generate a profile of genes overexpressed in human breast cancer. We have screened novel genes, of which "Clone 135" scored as a candidate oncogene that was overexpressed in tumor compared to matched normal tissue.

Characterization of the Differentially Expressed Genes in Human Breast Cancer using Subtractive Hybridization / 한국유방암학회지

PURPOSE: Although breast cancer the most common cancer for women remains a significant health problem, it has not been systematically studied until now. In an attempt to identify novel genes implicated in breast cancer development, we performed a suppression subtraction hybridization (SSH) with human breast cancer tissues, as well as with cloned genes, that are expressed more than in normal tissue. METHODS: After the identification of a novel gene, RT-PCR was performed to determine its mRNA expression in human breast cancers. In order to learn more about the expression profile of this gene, PCR was performed using various commercially available normal or carcinoma cell lines. The novel gene was found to be strongly expressed in breast cancer tissues and other carcinoma cell lines. To determine whether this novel gene was associated with cell cycle regulation, normal WI-38 fibroblast cells were stimulated with media containing 0.1% FBS for 48hours. RESULT: From the experimental results of the SSH, a novel clone, "Clone 135" which was strongly expressed in tumor compared to matched normal tissue, has been found. The novel clone was identified as being expressed in several tumor tissues and carcinoma cell lines. The time-course expression of this novel gene in the WI-38 (8PDL) normal lung cell line indicated a significant increase for G1-phase arrest. CONCLUSION: We have used a suppression subtractive hybridization (SSH) to generate a profile of genes overexpressed in human breast cancer. We have screened novel genes, of which "Clone 135" scored as a candidate oncogene that was overexpressed in tumor compared to matched normal tissue.

Detection of Differentially Expressed Genes in Glioblastoma by Suppression Subtractive Hybridization

OBJECTIVE: A variety of genetic alterations in human glioblastoma comprises signal transduction and cell cycle arrest control of cellular processes. Subtractive hybridization is potentially a faster method for identifying differentially expressed genes associated with a particular disease state. Using the technique of subtraction, we isolated novel genes that are overexpressed in glioblastoma tissue as compared to normal brain tissue. METHODS: We evaluated the differential expression of genes in each of hybridizing tester and driver cDNAs to digested 130 clones. After sequencing of 130 clones and homology search, this study performed to determine mRNA expression of the unknown gene, "clone 47", in brain tissue, glioblasoma, and several cancer cell lines by reverse transcription-polymerase chain reaction (RT-PCR). To test the time course for G0-phase arrest, serum stimulation and expression at various times for RT-PCR performed. RESULTS: We identified 23 novel genes by BLAST of the digested 130 clones. The expressions of "clone 47" mRNA of glioblastoma and several cancer lines were significantly higher than normal brain tissues and several normal cell lines. We confirmed the mRNA expression of "clone 47" was up-regulation for 0.5~1hr of WI-38 cell differentiation. CONCLUSION: The novel gene, "Clone 47" is upregulated in glioblastoma tissue and several cancer cell lines. This gene is time dependent activation during time course of serum stimulation. This result suggests that "clone 47" play a role in brain tumorigenesis and the activation of this "clone 47" may be necessary for the development of cancer.

Induction of Apoptosis by a Novel Bcl-2 Protein, Bak-like without a BH3 Domain

OBJECTIVE: In a variety of physiologic settings, cells are eliminated by apoptosis, a genetically encoded process of cellular suicide. Bak, a member of the Bcl-2 protein family, accelerates apoptosis by an unknown mechanism. Here, we describe the identification and characterization of a complementary DNA that encodes a previously unknown Bcl-2 homologue designated Bak-like. METHODS: We identified a splicing variant of Bak with a lacked BH3 domain from human full-length cDNA bank. The expression of Bak-like was examined by northern blot analysis and polymerase chain reaction. To investigate whether Bak-like might arise from alternative splicing of mRNA of Bak, Southern blot analysis was executed. Apoptosis in transfected HeLa cells was analyzed by direct counting of viable cells. We examined the location of Bak-like in individual living cells by using EGFP fusion constructs and confocal microscope. RESULTS: Bak-like cDNA coded a protein consisting of 101 amono acid, and conserved BH1 and BH2 domains like Bak but not BH3 domain. Bak-like mRNA was about 2.4kb similar to bak. Bak-like was assumed to be an alternative splicing variant of Bak and to concern with promotion of apoptosis. GFP-bak-like markedly changed its intracellular distribution, relocating within cells during apoptosis from a diffuse to a punctate pattern. CONCLUSION: Our results define a novel splicing form of the bak gene and demonstrate that this variant without a conserved BH3 domain appears to contain the BH1 and BH2 domains and the transmembrane sequence for apoptosis induction by channel-forming Bcl-2 proteins. Like Bak, Bak-like gene product primarily enhanced apoptotic cell death following an appropriate stimulus.

Molecular Genetics of Cerebral Aneurysm / 대한뇌혈관외과학회지

Subarachnoid hemorrhage(SAH) secondary to ruptured cerebral aneurysm is a complex trait, with both genetic and environmental risk factors playing an important part. The 30-day mortality rate of patients with SAH is 40% to 44%, with survivors suffering from major disability. Despite the high incidence and catastrophic consequences of a ruptured cerebral aneurysm and the fact that there is considerable evidence that predisposition to cerebral aneurysm has a strong genetic component, very little is understood with regard to the pathology and pathogenesis of this disease. Recent advances in molecular genetics provide evidence that genetic variants of different candidate genes are associated with the occurrence of cerebral aneurysm. This article reviews the evidence supporting a genetic predisposition to SAH from cerebral aneurysm, the conditions commonly associated with cerebral aneurysm, and the search for genetic risk factors.

Genetic Mutation of 5, 10-Methylenetetrahydrofolate Reductase in the Brain Neoplasms

OBJECTIVE: Recent epidermiologic studies suggested that alterations in folate metabolism as a result of polymorphism in the enzyme 5,10-methylenetetrahydrofolate reductase(MTHFR) have been frequently associated with neural tube defects, vascular disease, and some cancers. A common 677C->T polymorphism in the MTHFR gene results in thermolability and reduced MTHFR activity that decreases the pool of 5-methyltetrahydrofolate and increases the pool of 5,10-methylenetetrahydrofolate. A possible cause underlying altered DNA methylation could be an insufficient level of S-adenosylmethionine as a consequence of weaker alleles of MTHFR gene. Therefore, the weak MTHFR activity may underlie susceptibility to brain neoplasms. We now report the associations of MTHFR polymorphisms in three groups of adult brain tumors: gliomas, meningiomas and schwannomas. METHODS: We analyzed DNA of 71 brain tumors and 254 age- and sex-matched controls with a case-control study. MTHFR variant alleles were determined by a PCR-restriction fragment length polymorphism assay. RESULTS: The incidence of the MTHFR 677TT genotype was higher among 20 schwannoma cases compared with that of 254 controls, conferring a 5-fold increase of the risk of schwannomas(odds ratio, OR=4.75 ; 95% confidence index, CI=1.05-21.50). The homozygous mutant group had half the risk of meningioma(OR=0.42:95% CI = 0.11-1.58) compared with the homozygous normal or heterozygous genotypes. There was no significant difference in MTHFR 677TT genotype frequency between glioma group(19 cases) and control group(254 cases)(OR = 1.53 ; 95% CI = 0.30-7.73). CONCLUSION: The data indicate that the homozygous 677TT MTHFR genotype confers the significantly higher risk of schwannoma and the lower risk of meningioma. However, our study had limited a statistical power because of the small sample size, which is reflected in the wide CIs. Hence, these findings need to be confirmed in larger populations.