353 research outputs found
Third Annual Conference on Privacy, Security and Trust
No full textThis pre-print appears as a courtesy only. Please see the conference proceedings for the definitive version. Ching-Lung Fu is the corresponding author
[[alternative]]The Study of Furniture's Forms and Developments in Grand Ching
No full text[[abstract]]The Study of Furniture’s Forms and Developments in Grand Ching，beginning with the discussion of the borderland market in late Ming dynasty from Ching-tai-tsu Nurhaci, the way of use and ritual rules concerning are involved. After getting into mainland, based on prince consort Yung’s 「Twelve Beauties」painting and official files, to search for the characteristic of Yung Cheng dynasty. As to Chien Lung dynasty’s furniture, due to the sixty years in power, the source is various, and the developments are pluralistic. Under such complicated background and the brilliant appearance, how to define, where is its history significance, which type of style is contained, and what the material culture it reflected, is the main points of this dissertation.
[[alternative]]Genetic Alterations of Mismatch Repair Genes in Lung Tumorigenesis in Taiwan
No full text[[abstract]]貳、英文摘要
Lung cancer is the leading cause of cancer deaths in Taiwan. Genetically determined variation in DNA repair capacity is thought to contribute to susceptibility to tobacco-related cancers, such as lung cancer. In addition, defects in mismatch repair (MMR) genes have been implied in several types of sporadic and hereditary cancers in terms of inducing microsatellite instability (MI) of tumor cells. We have previously found that MI occurs in 41% of non-small cell lung cancer patients (NSCLC). However, there was only little report discussing the MMR gene alteration in lung cancer.
In order to elucidate the role of MMR in human lung carcinogenesis in Taiwan, we examined the alteration of two DNA mismatch repair genes, hMLH1 and hMSH2, in primary lung tumor tissues from NSCLC patients. We investigated the expression levels of hMLH1 and hMSH2 proteins in 169 and 77 NSCLC tumors , respectively, by the immunohistochemical analysis. Ninety-six (56.8%) patients had the alteration of hMLH1 protein expression; thirteen patients (17.1%) had the alteration of hMSH2 protein expression. In addtion, we found that the alteration of protein expression correlated with the aberrant mRNA expression by RT-PCR assay for both hMLH1 and hMSH2 (P=0.001). The alteration frequencies of mRNA expression were 55.8% and 15.6% for hMLH1 gene and hMSH2 gene, respectively.
To further examine the role of promoter hypermethylation in the identified alteration of protein expression, we also examine the association between hMLH1 promoter hypermathylation and hMLH1 protein expression. Forty-five (73.8%) patients containing hMLH1 promoter hypermethylation showed the alteration of protein expression (P = 0.001). The results suggested that mismatch repair plays a significant role in NSCLC tumorigenesis in Taiwan and that hMLH1 promoter hypermethylation is closely relative to the altered expression of mRNA and protein in the hMLH1 mismatch repair gene. Furthermore, we conducted a loss of heterozygosity (LOH) analysis at 3p21 microsatellite polymorphic marker D3S1768 for the deletion of hMLH1 region in a series of 39 NSCLC patients. The high percentage of LOH (56.4%) was observed at the D3S1768. The result suggested that loss of chromosome 3p21 may be also a critical event in the pathogenesis of lung cancer in Taiwan.
To investigate the association of hMLH1 alteration with MI, we also studied the correlation between MI and expression of hMLH1 mismatch repair protein in 73 patients. Twenty-seven of 37 MI-positive patients (73.0%) did not express hMLH1 protein. The data showed that MI was associated with altered hMLH1 expression (P=0.025). In addition, there was a tendency of association between LOH at D3S1768 (3p21) region and MI (P=0.092). The correlation suggests the alteration of the hMLH1 gene/ protein may be associated with microsatellite instability (MI) because of the failure to correct replication slippage errors.
In conclusion, our data suggest that alteration of hMLH1 gene and/or protein involved in lung tumorigenesis in Taiwan. The major alteration mechanism may be the promoter methylation of hMLH1 gene, and therefore inactivating its mRNA and protein expression. Moreover, LOH of the hMLH1 gene can also play an important role in alteration of hMLH1 gene. As regards hMSH2 gene, the data indicated that hMSH2 does not play a major etiological role in lung tumorigenesis in Taiwan. Validating the promoter hypermethyaltion and LOH in other mismatch rapair genes are worthy of further investigation in lung cancer tumorigenesis in Taiwan.
[[alternative]]Development of molecular diagnostic markers in sputum and plasma samples for lung cancer detection
No full text[[abstract]]Purpose: Lung cancer is the leading cause of cancer deaths in Taiwan. Traditional radiography and sputum cytology have not been successfully reducing lung cancer mortality. It’s urgent to develop more sensitive molecular marker panel for large early lung cancer screening.
Strategy: Carcinogenesis is a multi-step process resulting from the accumulation of errors in vital regulatory pathways. The present study was designed to select multiple DNA markers, which have high sensitivity and specificity to serve as diagnostic biomarkers for lung cancer detection.
Methods: Part I, we examined the promoter hypermethylation of three tumor suppressor genes (FHIT, p16INK4a, and RARβ) by methylation-specific PCR (MSP), and the instability of eight microsatellite markers (D3S1234, D3S1285, D5S1456, D9S286, D9S942, GATA49D12, D13S170, and D17S786) by loss of heterozygosity (LOH) and microsatellite instability (MSI) analyses in lung tumor cells and matched sputum specimens from 79 lung cancer patients. Part II, we examined the promoter hypermethylation of six tumor suppressor genes (BLU, CDH13, FHIT, p16INK4a, RARβ, and RASSF1A) by MSP assay in lung tumor tissues and matched plasma specimens from 63 lung cancer patients. In addition, there were additional sputum and plasma specimens from 22 cancer-free individuals to be the negative control of part I and part II studies.
Results: Part I sputum study, based on the results of sensitivity, specificity, and concordance from each marker analyzed, we selected seven biomarkers, which are LOH of D9S286, D9S942, GATA49D12, and D13S170, MSI of D9S942, and methylation of p16INK4a and RARβ. In addition, the odds ratio of D9S942 LOH in sputum was 4.9 (95% confidence interval, CI: 1.23~21.73, P=0.024), and the odds ratio of p16INK4a methylation in sputum was 3.29 (95% CI: 1.00~14.93, P=0.049). Using a definition that patient with cancer risk had alteration in more than two among seven selected biomarkers, we achieved a sensitivity of 81%, a specificity of 72%, and a concordance of 77%. In addition, the regression model calculated from the training set (53 cancer patients, 13 cancer-free individuals) had a match score of 80% while applying to the test set (26 cancer patients, 9 cancer-free individuals). The new regression model Y = -0.87＋0.79 (D9S286 LOH)＋1.96 (D9S942 LOH)＋2.24 (GATA49D12 LOH)＋12.19 (D13S170 LOH)＋11.02 (D9S942 MSI)＋0.70 (p16INK4a methyl)＋1.25 (RARβ methyl) thus was generated by calculating all cases (79 cancer patients, 22 cancer-free individuals) and this led to a sensitivity of 86%, a specificity of 22%, and a concordance of 78%.
Part II plasma study, p16INK4a, RARβ, and RASSF1A genes had higher promoter hypermethylation frequencies. In addition, the odds ratio of p16INK4a methylation and RASSF1A methylation in plasma was 5.56 (95%CI: 1.41~37.22, P=0.012) and 5.48 (95% CI: 1.40~37.00, P=0.014), respectively. Using a definition of risk individual showing alteration in more than one of the three selected biomarkers, we achieved a sensitivity of 74%, a specificity of 78%, and a concordance of 75%. The regression model calculated from the training set (43 cancer patients, 13 cancer-free individuals) had a match score of 83% comparing to the test set (20 cancer patients, 9 cancer-free individuals). The new regression model Y = 0.19＋0.52 (BLU methyl)＋1.92 (p16INK4a methyl)＋1.52 (RASSF1A methyl), which calculated by overall cases (63 cancer patients, 22 cancer-free individuals), achieved a sensitivity of 77%, a specificity of 90%, and a concordance of 79%. Therefore, the new regression model will be used in the future clinical screening because its high sensitivity, specificity, and concordance.
Conclusion: These selected early-etiologically associated biomarkers can potentially be tested as supplement biomarkers for early lung cancer detection in the future.
[[alternative]]Loss of heterozygosity and its correlation with genetic polymorphisms of double-stranded break repair in lung cancer
No full text[[abstract]]Background: Most tumor suppressor genes (TSGs) are recessive. Both copies of TSGs need to be inactivated for losing their biological function. One allele may be inactivated by point mutation and methylation change. The other is frequently inactivated by a large deletion involving the gene of interest as well as adjacent stretches of DNA. Thus, searches for genomic regions frequently deleted by loss of heterozygosity (LOH) in cancer have helped to identify or confirm the location of several TSGs. In addition, lung cancer cells frequently exhibit marked chromosome instability such as high fractional allelic loss (FAL, an indication of genomic instability). We then postulated that genetic polymorphism of the double strand-break repair (DSBR) genes, Ku70, Ku80, Ligase IV, and XRCC4, may involve in lung cancer susceptibility. Purposes and Methods: To define the minimal deletion regions (MDRs) that may contain TSGs, we used 112 microsatellite markers to perform LOH analysis in tumors and corresponding normal tissues from 48 adenocarcinomas (ADs) and 36 squamous carcinomas (SQs) lung cancer patients. In addition, we investigated the frequency of four NHEJ (non-homologous end-joining) pathway genes Ku70 (C217G), Ku80 (G92504A), Ligase IV (G3539A, Thr9Ile), and XRCC4 (G275626A, splice-site) polymorphisms in 151 lung cancer patients and 162 cancer-free individuals. The joint effects of these four genes contributed to an increased cancer risk were also analyzed. Results: The average LOH frequency was 48% in AD and 42% in SQ. In addition, 12 MDRs and 13 MDRs were revealed in AD and SQ, respectively. The data suggested that different mechanisms may be involved in the development of AD and SQ. The average interval of 25 MDRs was 5.18 cM. We found that the loss of MDRA7p1 (D7S1818-D7S506, 7p12.1-7p12.3) was associated with AD, and the loss of MDRS9p1 (D9S2169-D9S286, 9p24.1-9p24.3) was associated with SQ and smoking. Furthermore, stage-specific and common deletion markers were identified, suggesting their role in tumor progression. Several candidate genes were annotated by the web-search tools and they can be target genes for further analyses. There was no significant difference in the genotype distribution of Ku70 (C217G), Ku80 (G92504A) polymorphism between lung cancer patients and cancer-free controls (P>0.05, multivariate logistic regression model). However, we found that patients with homozygous or heterozygous variant genotype (A/A or A/G) of Ligase IV (G3539A, Thr9Ile) polymorphism had a tendency to be associated with lung cancer risk (adjusted odds ratio, aOR=1.64, 95% confidence interval, CI=1.03-2.62, adjusted P=0.038). The patients with homozygous variant genotype (G/G) of XRCC4 (G275626A, splice-site) polymorphism also showed a significantly increase lung cancer risk (aOR=2.38, 95% CI=1.05-5.76, adjusted P=0.043). In addition, we found that the G/G frequency of XRCC4 was significant higher in high FAL patients than low FAL patients. (adjusted P=0.016). Furthermore, the joint effect was found between Ku70 and Ku80 as well as Ligase IV and XRCC4. The increased risk of developing lung cancer were 4.65 (95% CI=1.19-24.08, adjusted P=0.040) and 8.75 (95% CI=2.27-57.77, adjusted P=0.006), respectively, when patients harboring two putative high-risk genotypes in these genes. Conclusions: The LOH analysis and definition of MDRs can potentially be used for the clinical association study and the cloning of new TSGs whose aberration contributes to lung tumorigenesis. In addition, the polymorphic results suggest that the polymorphism in four NHEJ genes may be associated with the susceptibility to lung cancer. Our data provide new evidence that the NHEJ putative risk alleles may have a joint effect on the genomic instability of lung cancer.
Integrative Omic Study to Identify Potential Dietary Supplement for Osteoporosis Treatment
No full text[[alternative]]Etiological association of alterations in p53-hdm2-p14ARF pathway with lung tumorigenesis in Taiwan
No full text[[abstract]]Lung cancer is the leading and second cause of cancer deaths among women and men in Taiwan, respectively. However, the molecular mechanisms involved in lung tumorigenesis in Taiwan remain poorly defined. There is increasing evidence that alterations in tumor suppressor genes and oncogenes are common in many forms of human cancer including lung cancer. We found that p53 gene mutation frequency was 17% in resected non-small cell lung cancers (NSCLC). However, p53 protein overexpression frequency was 48%. To further identify the molecular basis for this p53 immunohistochemical abnormality, we performed a genetic and epigenetic study of the p53 upstream proteins, p14ARF and hdm2, in NSCLC patients. Specimens of resected NSCLC from 113 patients were recruited in this study. Protein expression and mRNA expression of p14ARF and hdm2 were examined by immunoshitochemistry and reverse transcriptase-polymerase chain reaction (RT-PCR), respectively. Methylation-based PCR assay was conducted to detect promoter methylation of the p14ARF gene. Loss of heterozygosity (LOH), homozygous deletion, and mutation of p14ARF gene were also examined. All data of p14ARF and hdm2 analyses were compared among patients with various clinicopathological parameters and with the p53 protein expression level. The data indicated that 45% and 41% lung cancer patients showed low or absent of hdm2 protein and mRNA expression, respectively. We also found that alternative splicing was the major mechanism which caused hdm2 gene alteration. In addition, we examined the frequency of protein expression of Akt kinase because Akt is known to associate with phosphorylation and nuclear localization of hdm2. The results indicated that the negative Akt kinase protein expression was correlated with negative hdm2 protein expression. With regard to p14ARF analyses, the data indicated that 34% and 31% lung cancer patients showed low or absent of p14ARF protein and mRNA expression, respectively. The frequency of p14ARF promoter hypermethylation, LOH, homozygous deletion, and mutation was 30%, 24%, 9% and 2%, respectively. We suggested that promoter hypermethylation was the major mechanism which caused p14ARF gene alteration. Note that 92% (35/38) patients with p53 overexpression showed absence or low expression of hdm2 protein and near overexpression of p14ARF protein. It indicated that the p53 overexpression was indeed induced by the dysregulation of the upstream proteins, hdm2 and p14ARF. Interestingly, most of the NSCLC patients with dysregulation of the p53-hdm2-p14ARF pathway were suffered late stage and SQ type of cancer. In addition, the patients with p53 overexpression had poor prognosis (P=0.013).
The study was the first report which examines all possible alteration pathways in p53-hdm2-p14ARF gene/protein deregulation in the same series of NSCLC, and examines their relationship with the clinical data of NSCLC. In addition, it was also the first report on the alternative splicing of hdm2 mRNA in lung cancer. In conclusion, the alteration of p53-hdm2-p14ARF regulation pathway plays an important role in tumorigenesis of lung cancer in Taiwan, and could be potentially used as a molecular prognostic marker.
[[alternative]]HIC1 alteration and its association with deregulation of p53/SIRT1-mediated control in lung cancer
No full text[[abstract]]Purpose: We have previously reported that the chromosomal regions at 17p13.3 showed a high frequency of loss of heterozygosity in tumors from non-small cell lung cancer (NSCLC) patients. HIC1 (hypermethylated in cancer 1) is a candidate tumor suppressor gene at 17p13.3 and is epigenetically inactivated in many human cancers. A circular regulation of HIC1, SIRT1 deacetylase, and p53 is proposed for modulation of cellular responses to DNA damage in cell and animal studies. However, the etiological role of HIC1 alteration and its correlation with p53 and SIRT1 deregulation have never been examined in the same series of human cancer patients. Therefore, we investigated the alterations of HIC1 at the DNA, RNA, and protein levels, and their correlation with deregulation of p53/SIRT-mediated control in lung cancer. Materials and Methods: The alterations of HIC1 including loss of protein/mRNA expression and promoter hypermethylation as well as their clinical correlations were examined in 108 NSCLC patients. In addition, the expression of acetylated p53 and SIRT1 deacetylase was examined by Western blot. We also treated A549 lung cancer cell line with demethylation reagent 5’aza 2’deoxycytidine (5’-Aza-2’-dC) and SIRT1 inhibitor nicotinamide (vitamin B3) to investigate the effects in the regulation of HIC1, p53 and SIRT1. Results: Overall, 65.5%, 75.9%, and 40% of NSCLC patients showed low protein, low mRNA, and promoter hypermethylation for HIC1 gene, respectively. A high concordance was observed between low mRNA expression and promoter hypermethylation for the HIC1 gene (P<0.05). Low mRNA expression of HIC1 was significantly associated with low acetylated p53, supporting that HIC1 is a transactivating target of p53 (P=0.016). In addition, low acetylated p53 is significantly associated with high SIRT1 protein (P=0.002), and high SIRT1 protein is significantly associated with low HIC1 protein (P=0.004). In addition, in the A549 lung cancer cells, which showed low levels of HIC1 mRNA and promoter hypermethylation, treated with demethylation reagent 5’-Aza-2’-dC, the HIC1 mRNA and protein expressions were restored along with the demethylation of HIC1 promoter. In the A549 cells treated with SIRT1 inhibitor nicotinamide, an increase of p53 acetylation and HIC1 re-expression were seen. In addition, promoter hypermethylation of HIC1 gene was tended to be associated with adenocarcinomas than with squamous carcinomas (P=0.059), whereas deacetylation of p53 was tended to be associated with squamous carcinomas than with adenocarcinomas (P=0.046). Conclusion: HIC1 alteration plays an important role in lung tumorigenesis and the predominant mechanisms of HIC inactivation were HIC1 promoter hypermethylation and p53 deacetylation. The present study shows the first clinical evidence that alteration of HIC1/SIR1/p53 pathway is involved in tumorigenesis.
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