Biomedical subjects

Donghui Li

Publications and source records attributed to Donghui Li.

At least 19 recordsLinked to original sources

PubMed2007

Effects of base excision repair gene polymorphisms on pancreatic cancer survival.

To explore the association between single nucleotide polymorphisms of DNA repair genes and overall survival of patients with pancreatic cancer, we conducted a study in 378 cases of pancreatic adenocarcinoma who were treated at The University of Texas M. D. Anderson Cancer Center between February 1999 and October 2004 and were followed up to April 2006. Genotypes were determined using genomic DNA and the MassCode method. Overall survival was analyzed using the Kaplan-Meier plot, log-rank test and Cox regression. We observed a strong effect of the POLB A165G and T2133C genotypes on overall survival. The median survival time (MST) was 35.7 months for patients carrying at least 1 of the 2 homozygous variant POLB GG or CC genotypes, compared with 14.8 months for those carrying the AA/AG or TT/TC genotypes (p = 0.02, log rank test). The homozygous variants of hOGG1 G2657A, APEX1 D148E and XRCC1 R194W polymorphisms all showed a weak but significant effect on overall survival as demonstrated by either log rank test or multivariate COX regression after adjusting for other potential confounders. In combined genotype analysis, a predominant effect of the POLB homozygous variants on survival was observed. When POLB was not included in the model, a slightly better survival was observed among those carrying none of the adverse genotypes than those carrying at least one of the adverse genotypes. These observations suggest that polymorphisms of base excision repair genes significantly affect the clinical outcome of patients with pancreatic cancer. These observations need to be confirmed in a larger study of homogenous patient population.

Aged↗

PubMed2007

K-ras mutation and p16 and preproenkephalin promoter hypermethylation in plasma DNA of pancreatic cancer patients: in relation to cigarette smoking.

OBJECTIVES: To examine the profiles of K-ras mutations and p16 and preproenkephalin (ppENK) promoter hypermethylation and their associations with cigarette smoking in pancreatic cancer patients. METHODS: In plasma DNA of 83 patients with untreated primary pancreatic ductal adenocarcinoma, DNA hypermethylation was determined by methylation-specific polymerase chain reaction and K-ras codon 12 mutations by enriched-nested polymerase chain reaction followed by direct sequencing. Information on smoking exposure was collected by in-person interview. Pearson chi test and Fisher exact test were used in statistical analysis. RESULTS: K-ras mutations, ppENK, and p16 promoter hypermethylation were detected in 32.5%, 29.3%, and 24.6% of the patients, respectively. Sixty-three percent (52/83) of patients exhibited at least one of the alterations. Smoking was associated with the presence of K-ras mutations (P = 0.003). A codon 12 G-to-A mutation was predominantly observed in regular smokers and in heavy smokers (pack-year of smoking > or =36). Smoking was not associated with p16 or ppENK hypermethylation. CONCLUSIONS: These preliminary observations suggest that plasma DNA might be a useful surrogate in detecting genetic and epigenetic alterations of pancreatic cancer. The findings on the association between K-ras mutation and smoking were in consistency with previous studies. Further studies on environmental modulators of epigenetic changes in pancreatic cancer are warranted.

Adenocarcinoma↗

PubMed2006

Polymorphisms of phase II xenobiotic-metabolizing and DNA repair genes and in vitro N-ethyl-N-nitrosourea-induced O6-ethylguanine levels in human lymphocytes.

This study tested the hypothesis that genetic variants of phase II detoxification enzymes and DNA repair proteins affect individual response to DNA damage from alkylating agents. In 171 healthy individuals, an immunoslot blot assay was used to measure O6-ethylguanosine (O6-EtGua) adduct levels in peripheral blood lymphocytes treated with N-ethyl-N-nitrosourea (ENU) in vitro. The genotypes of GSTM1, GSTT1, GSTP1 I(105)V and A(114)V, MGMT L(84)F and I(143)V, XPD D(312)N and K(751)Q, and XRCC3 T(241)M were determined. Demographic and exposure information was collected by in-person interview. Student's t-test, analysis of (co)variance, and multiple linear regression models were used in statistical analyses. The mean and median (range) O6-EtGua levels were 94.6 and 84.8 (3.2-508.1)fmol/g DNA, respectively. The adduct level was significantly lower in people who smoked >or=25 years than that in never-smokers (square-root transformed mean values 8.20 versus 9.37, P=0.03). Multiple linear regression models revealed that GSTT1 (beta=-2.36, P=0.009) polymorphism was a significant predictor of the level of adducts in 82 never-smokers, whereas the number of years smoked (beta=-0.08, P=0.005) and XRCC3 T(241)M (beta=2.22, P=0.007) in 89 ever-smokers. The association between GSTP1 I(105)V, MGMT I(143)V, and XPD D(312)N with the level of adducts was not conclusive. Each polymorphism could explain 2-10% of the variation of the adduct level. These observations suggest that GSTT1 null and XRCC3 T(241)M polymorphism may have some functional significance in modulating the level of ENU-induced DNA damage and these effects are smoking-dependent. Results from this exploratory study need to be confirmed in other experimental systems.

Aged↗

PubMed2006

Promoter polymorphism (-786t>C) in the endothelial nitric oxide synthase gene is associated with risk of sporadic breast cancer in non-Hispanic white women age younger than 55 years.

BACKGROUND: Nitric oxide (NO) is constitutively synthesized in the endothelium by endothelial nitric oxide synthase (eNOS) and acts as a pleiotropic regulator involved in carcinogenesis. Most breast cancers develop from mammary epithelial cells; therefore, NO may play a role in their development. It was hypothesized that eNOS polymorphisms are associated with risk of breast cancer. METHODS: In the current hospital-based case-control study of 421 non-Hispanic white women with sporadic breast cancer and 423 frequency-matched control subjects, we genotyped 3 polymorphisms of eNOS (i.e., -786T>C, the 27-base pair [bp] variable number of tandem repeats [VNTR] in intron 4, and 894G>T [Glu298Asp]) and assessed their associations with risk of breast cancer. RESULTS: It was found that, compared with -786TT, the -786C variant genotypes were associated with a significantly increased risk of breast cancer in an allele dose-dependent manner (adjusted odds ratio [OR], 1.33 [95% confidence interval (95% CI)], 0.99-1.77 for -786TC; and OR, 1.79 [95% CI, 1.11-2.87] for -786CC; P(trend) = .007), but 27-bp VNTR and 894G>T genotypes were not. Stratification analysis demonstrated that the risk associated with -786C variant genotypes (-786TC/CC) was more pronounced in smokers and in those 50 years or older (OR, 1.82 [95% CI, 1.19-2.80] and OR, 2.08 [95% CI, 1.25-3.45], respectively), and in the estrogen and progesterone receptor-negative cases (OR, 1.70 [95% CI, 1.10-2.62] and OR, 1.57 [95% CI, 1.07-2.32], respectively). Furthermore, the C4G haplotype derived from the observed genotypes was also associated with a significantly increased risk of breast cancer (OR, 2.16; 95% CI, 1.07-4.36). CONCLUSIONS: The results suggest that eNOS polymorphisms (especially -786T>C) may play a role in the development of sporadic breast cancer.

Adult↗

PubMed2006

Meta- and pooled analyses of the cytochrome P-450 1B1 Val432Leu polymorphism and breast cancer: a HuGE-GSEC review.

The association between the cytochrome P-450 1B1 (CYP1B1) Val432Leu polymorphism and breast cancer was assessed through a meta-analysis of all published case-control studies and a pooled analysis of both published and unpublished case-control studies from the Genetic Susceptibility to Environmental Carcinogens (GSEC) database ( www.upci.upmc.edu/research/ccps/ccontrol/g_intro.html ). GSEC is a collaborative project that gathers information on studies of metabolic gene polymorphisms and cancer. Thirteen articles were included in the meta-analysis (14,331 subjects; 7,514 cases, 6,817 controls); nine data sets were included in the pooled analysis (6,842 subjects; 3,391 cases, 3,451 controls). A summary meta- or pooled estimate of the association between the CYP1B1 Val432Leu polymorphism and breast cancer could not be calculated because of statistically significant heterogeneity in the point estimates among studies. No association between the CYP1B1 Val432Leu polymorphism and breast cancer was observed in Asians (for Val/Val and Val/Leu combined, odds ratio (OR) = 1.0, 95% confidence interval (CI): 0.8, 1.2). An inverse association was observed in populations of mixed/African origin (OR = 0.8, 95% CI: 0.7, 0.9). The pooled analysis suggested a possible association in Caucasians (for Val/Val and Val/Leu combined, OR = 1.5, 95% CI: 1.1, 2.1), with effect modification across age categories. The observed effect of age on the association in Caucasians indicates that further studies are needed on the role of CYP1B1 Val432Leu in estrogen metabolism according to age, ethnicity, and menopausal status.

Aryl Hydrocarbon Hydroxylases↗

PubMed2006

The state transition mechanism - simply depending on light-on and -off in Spirulina platensis.

The state transition in cyanobacteria is a long-discussed topic of how the photosynthetic machine regulates the excitation energy distribution in balance between the two photosystems. In the current work, whether the state transition is realized by "mobile phycobilisome (PBS)" or "energy spillover" has been clearly answered by monitoring the spectral responses of the intact cells of the cyanobacterium Spirulina platensis. Firstly, light-induced state transition depends completely on a movement of PBSs toward PSI or PSII while the redox-induced one on not only the "mobile PBS" but also an "energy spillover". Secondly, the "energy spillover" is triggered by dissociation of PSI trimers into the monomers which specially occurs under a case from light to dark, while the PSI monomers will re-aggregate into the trimers under a case from dark to light, i.e., the PSI oligomerization is reversibly regulated by light switch on and off. Thirdly, PSI oligomerization is regulated by the local H(+) concentration on the cytosol side of the thylakoid membranes, which in turn is regulated by light switch on and off. Fourthly, PSI oligomerization change is the only mechanism for the "energy spillover". Thus, it can be concluded that the "mobile PBS" is a common rule for light-induced state transition while the "energy spillover" is only a special case when dark condition is involved.

Biochemistry↗

PubMed2006

Selected polymorphisms of DNA repair genes and risk of pancreatic cancer.

BACKGROUND: Genetic variants of DNA repair genes may contribute to pancreatic carcinogenesis. O(6)-methylguanine-DNA methyltransferase (MGMT) is the major protein that removes alkylating DNA adducts, and apurinic/apyrimidinic endonuclease 1 (APE1) and X-ray repair cross-complementing group 1 (XRCC1) play important roles in the base excision repair pathway. METHODS: We investigated the association between polymorphisms of MGMT (Leu(84)Phe and Ile(143)Val), APE1 (Asp(148)Glu), and XRCC1 (Arg(194)Trp and Arg(399)Gln) and risk of pancreatic cancer in a case-control study. Exposure information from 384 patients with primary pancreatic ductal adenocarcinoma and 357 cancer-free healthy controls were collected and genomic DNAs were genotyped for five markers. Controls were frequency matched to patients by age at enrollment (+/-5 years), gender, and race. We estimated odds ratios (ORs) and 95% confidence intervals (CIs) by using unconditional logistic regression models. RESULTS: There was no significant main effect or interaction with smoking of these genetic variants on the risk of pancreatic cancer. However, the XRCC1(194) polymorphism had a significant interaction with the APE1(148) (p=0.005) or MGMT(84) polymorphism (p=0.02) in modifying the risk of pancreatic cancer. CONCLUSIONS: This study suggests that polymorphisms of genes involved in the repair of alkylating DNA adduct and DNA base damage may play a role in modulating the risk of pancreatic cancer. Larger studies are required to validate these preliminary findings. The mechanism of the combined genotype effects remains to be elucidated.

Adult↗

PubMed2006

Polymorphisms and haplotypes of the NBS1 gene are associated with risk of sporadic breast cancer in non-Hispanic white women <or=55 years.

DNA double-strand breaks (DSBs) may lead to genomic instability and cancer if unrepaired. Nijmegen breakage syndrome 1 (NBS1) protein is one of the key proteins that participates in recognition and repair of DSBs in humans. We hypothesized that polymorphisms of NBS1 are associated with breast cancer risk. We selected three NBS1 haplotype-tagging polymorphisms (i.e. 924T>C, 8360G>C and 30537G>C) to represent all common (>or=5%) haplotypes reported in the National Institute of Environmental Health Sciences database and to reconstruct haplotypes. In a hospital-based case-control study of 421 non-Hispanic white patients with sporadic breast cancer ( C polymorphism. Furthermore, the derived haplotypes were associated with risk in a dose-response manner as the number of variant (risk) alleles (i.e. 8360C, 924C or 30537C) increased (adjusted OR = 1.07, 95% CI = 0.78-1.46 for 1-2 variant alleles; adjusted OR = 2.47, 95% CI = 1.48-4.14 for 3-6 variant alleles; P(trend) = 0.006). These findings suggest that NBS1 polymorphisms and haplotypes may contribute to the etiology of sporadic breast cancer in young non-Hispanic white women. Large studies are warranted to confirm these findings.

Aged↗

PubMed2006

Significant effect of homologous recombination DNA repair gene polymorphisms on pancreatic cancer survival.

Genetic variation in DNA repair may affect the clinical response to cytotoxic therapies. We investigated the effect of six single nucleotide polymorphisms of the RecQ1, RAD54L, XRCC2, and XRCC3 genes on overall survival of 378 patients with pancreatic adenocarcinoma who were treated at University of Texas M.D. Anderson Cancer Center during February 1999 to October 2004 and were followed up to October 2005. Genotypes were determined using the MassCode method. Survival was determined from pathologic diagnosis to death. Patients who were alive at the last follow-up evaluation were censored at that time. Kaplan-Meier plot, log-rank test, and Cox regression were used to compare overall survival by genotypes. A significant effect on survival of all patients was observed for RecQ1 and RAD54L genes. The median survival time was 19.2, 14.7, and 13.2 months for the RecQ1 159 AA, AC, and CC genotypes, and 16.4, 13.3, and 10.3 months for RAD54L 157 CC, CT, and TT genotypes, respectively. A significantly reduced survival was associated with the variant alleles of XRCC2 R188H and XRCC3 A17893G in subgroup analysis. When the four genes were analyzed in combination, an increasing number of adverse alleles were associated with a significantly decreased survival. Subgroup analyses have shown that the genotype effect on survival was present among patients without metastatic disease or among patients who receive radiotherapy. These observations suggest that polymorphisms of genes involved in the repair of DNA double-strand breaks significantly affect the clinical outcome of patients with pancreatic cancer.

Adenosine Triphosphatases↗

PubMed2006

Single nucleotide polymorphisms of RecQ1, RAD54L, and ATM genes are associated with reduced survival of pancreatic cancer.

PURPOSE: Our goal was to determine whether single nucleotide polymorphisms (SNPs) in DNA repair genes influence the clinical outcome of pancreatic cancer. PATIENTS AND METHODS: We evaluated 13 SNPs of eight DNA damage response and repair genes in 92 patients with potentially resectable pancreatic adenocarcinoma. All patients were treated with neoadjuvant concurrent gemcitabine and radiotherapy with or without a component of induction gemcitabine/cisplatin at The University of Texas M.D. Anderson Cancer Center (Houston, TX) from February 1999 to August 2004 and observed through August 2005. Response to the pretreatment was assessed by evaluating time to tumor progression and overall survival. Kaplan-Meier plot, log-rank test, and Cox regression were used to compare survival of patients according to genotype. RESULTS: The RecQ1 A159C, RAD54L C157T, XRCC1 R194W, and ATM T77C genotypes had a significant effect on the overall survival with log-rank P values of .001, .004, .001, and .02, respectively. A strong combined effect of the four genotypes was observed. Patients with none of the adverse genotypes had a mean survival time of 62.1 months, and those with one, two, or three or more at-risk alleles had median survival times of 27.5, 14.4, and 9.9 months, respectively (log-rank P < .001). There is a significant interaction between the RecQ1 gene and other genotypes. All four genes except XRCC1 remained as independent predictors of survival in multivariate Cox regression models adjusted for other clinical predictors. CONCLUSION: These observations support the hypothesis that polymorphic variants of DNA repair genes affect clinical prognosis of patients with pancreatic cancer.

Adenosine Triphosphatases↗

PubMed2006

The XPD Asp312Asn and Lys751Gln polymorphisms, corresponding haplotype, and pancreatic cancer risk.

We evaluated the association between the XPD exon 10 Asp(312)Asn and exon 23 Lys(751)Gln polymorphisms and the risk of pancreatic cancer in a hospital-based study of 344 patients and 386 controls frequency matched by age, gender, and race. Stratified analyses showed ever smokers carrying the Asn(312)Asn genotype had a significantly reduced risk when compared with those carrying the (312)Asp allele (OR=0.46, 95% confidence interval 0.24-0.88) (P for interaction=0.03). The (312)Asp-(751)Gln was identified as the putative at risk haplotype. Our study shows that the XPD gene polymorphism could be a genetic risk modifier for smoking-related pancreatic cancer.

Adenocarcinoma↗

PubMed2006

Protein fragment domains identified using 2D gel electrophoresis/MALDI-TOF.

We previously reported a protein expression profiling experiment conducted on human pancreatic tissues using 2D gel electrophoresis and mass spectrometry. Here, 18 spots that were identified in the gel at molecular weights more than 10 kDa lower than database values are characterized. The matrix-assisted laser desorption/ionization mass spectrometry coverage is sufficient to identify the protein region present in each spot. Most of the fragments correspond to processed chains and known structural or functional domains, which may result from limited proteolysis.

Amino Acid Sequence↗

PubMed2005

Polymorphisms of cytochrome P4501A2 and N-acetyltransferase genes, smoking, and risk of pancreatic cancer.

To test the hypothesis that genetic variation in the metabolism of tobacco carcinogens, such as aromatic amines (AA) and heterocyclic amines (HCA), contributes to pancreatic cancer, we have examined genetic polymorphisms of three key enzymes, i.e. cytochrome P450 1A2 (CYP1A2) and N-acetyltransferase 1 and 2 (NAT1 and NAT2), in a hospital-based case-control study of 365 patients with pancreatic adenocarcinoma and 379 frequency-matched healthy controls. Genotypes were determined using PCR-restriction fragment length polymorphism (RFLP) and Taqman methods. Smoking information was collected by personal interview. Adjusted odds ratio (AOR) and 95% confidence interval (CI) was estimated by unconditional multivariate logistic regression analysis. We found that the NAT1 'rapid' alleles were associated with a 1.5-fold increased risk of pancreatic cancer (95% CI: 1.0-2.1) with adjustment of potential confounders. This effect was more prominent among never smokers (AOR: 2.4, 95% CI: 1.4-4.3) and females (AOR: 1.8, 95% CI: 1.0-3.1). Some genotypes were significantly associated with increased risk for pancreatic cancer among smokers, especially heavy smokers (<20 pack years). For example, heavy smokers with the CYP1A2*1D (T-2467delT) delT, CYP1A2*1F(A-163C) C allele, NAT1 'rapid' or NAT2 'slow' alleles had an AOR (95% CI) of 1.4 (0.7-2.3), 1.9 (1.1-3.4), 3.0 (1.6-5.4) and 1.5 (0.8-2.6), respectively, compared with never smokers carrying the non-at-risk alleles. These effects were more prominent in females than in males. The corresponding AOR (95% CI) was 3.1 (1.0-8.0), 3.8 (1.5-10.1), 4.5 (1.6-12.7) and 2.0 (0.8-5.1) for females versus 1.0 (0.4-1.9), 1.1 (0.5-2.4), 2.1 (1.0-4.6) and 1.1 (0.5-2.6) for males. A significant synergistic effect of CYP1A2*1F C allele and NAT1"rapid" alleles on the risk for pancreatic cancer was also detected among never smokers (AOR: 2.9, 95% CI: 1.2-6.9) and among females (AOR: 2.5, 95% CI: 1.1-5.7). These data suggest that polymorphisms of the CYP1A2 and NAT1 genes modify the risk of pancreatic cancer.

Adenocarcinoma↗

PubMed2005

The rapamycin analog CCI-779 is a potent inhibitor of pancreatic cancer cell proliferation.

We present immunohistochemical evidence that the mTOR/p70s6k pathway is activated in pancreatic tumors and show that the mTOR inhibitor and rapamycin analog CCI-779 potently suppresses the proliferation of pancreatic cancer cells. Consistent with a recent study, CCI-779 increased c-Jun phosphorylation (Ser63) in a dose- and time-dependent manner, and induced apoptosis in p53-defective BxPC-3 cells. In contrast to the study, however, we observed that CCI-779 concomitantly increased c-Jun protein levels and that its ability to induce apoptosis might not require the activated c-Jun. Furthermore, CCI-779 neither induced c-Jun phosphorylation in other p53-defective pancreatic cancer cells (MiaPaCa-2) nor inhibited their proliferation. c-Jun, in fact, appeared to be partly responsible for the resistance of MiaPaCa-2 cells to CCI-779. Together, these results indicate a complex role for c-Jun in cellular responses to CCI-779 and provide an important basis for investigating CCI-779 further as a potential therapeutic agent for pancreatic tumors.

Antineoplastic Agents↗

PubMed2005

Molecular basis for the RIN4 negative regulation of RPS2 disease resistance.

Recent studies have demonstrated that RPS2, a plasma membrane-localized nucleotide binding site/leucine-rich repeat protein from Arabidopsis thaliana, associates with RPM1 Interacting Protein 4 (RIN4) and that this association functions to modulate the RPS2-mediated defense pathway in response to the bacterial effector protein AvrRpt2. In addition to negatively regulating RPS2 activity, RIN4 is also a target of AvrRpt2, a Cys protease and cognate bacterial effector protein of RPS2. Nicotiana benthamiana has been employed as a heterologous expression system to characterize the RPS2-RIN4 association, defining the domains in RIN4 required for the negative regulation of RPS2 activity. Upon inoculation of N. benthamiana leaves with Agrobacterium tumefaciens expressing RPS2, a rapid hypersensitive response (HR) is detected with 22 h of infiltration. The HR can be blocked by infiltrating the leaf with A. tumefaciens expressing RPS2 in the presence of RIN4, recapitulating the ability of RIN4 to interfere with RPS2-mediated resistance in Arabidopsis. Moreover, in the presence of RIN4, the RPS2-mediated HR can be restored by the delivery of AvrRpt2 via A. tumefaciens. This assay has been developed as a phenotypic marker for (1) the HR-inducing phenotype associated with RPS2, (2) negative regulation of RPS2 by RIN4, and (3) the AvrRpt2-mediated disappearance of RIN4. Here, we present a series of deletion and site-directed mutation analyses to identify amino acids in RIN4 required for the RPS2-RIN4 association and to distinguish these from residues in RIN4 that serve as a target sequence for AvrRpt2. In addition to characterizing the RPS2-RIN4 association in N. benthamiana, we have moved forward to show that the biological relevance of these amino acid changes is applicable in Arabidopsis as well. To this end, we have identified specific amino acids within the C-terminal half of RIN4 that are required for RPS2 regulation and association.

Agrobacterium tumefaciens↗

PubMed2005

Plasma protein profiling for diagnosis of pancreatic cancer reveals the presence of host response proteins.

Plasma protein profiling using separations coupled to matrix-assisted laser desorption ionization mass spectrometry (MALDI MS) has great potential in translational research; it can be used for biomarker discovery and contribute to disease diagnosis and therapy. Previously reported biomarker searches have been done solely by MS protein profiling followed by bioinformatics analysis of the data. To add to current methods, we tested an alternative strategy for plasma protein profiling using pancreatic cancer as the model. First, offline solid-phase extraction is done with 96-well plates to fractionate and partially purify the proteins. Then, multiple profiling and identification experiments can be conducted on the same protein fractions because only 5% of the fractions are used for MALDI MS profiling. After MALDI MS analysis, the mass spectra are normalized and subjected to a peak detection algorithm. Over three sets of mass spectra acquired using different instrument variables, approximately 400 unique ion signals were detected. Classification schemes employing as many as eight individual peaks were developed using a training set with 123 members (82 cancer patients) and a blinded validation set with 125 members (57 cancer patients). The sensitivity of the study was 88%, but the specificity was significantly lower, 75%. The reason for the low specificity becomes apparent upon protein identification of the ion signals used for the classification. The identifications reveal only common serum proteins and components of the acute phase response, including serum amyloid A, alpha-1-antitrypsin, alpha-1-antichymotrypsin, and inter-alpha-trypsin inhibitor.

Acute-Phase Proteins↗

PubMed2005

Diagnostic protein discovery using liquid chromatography/mass spectrometry for proteolytic peptide targeting.

A peptide targeting method has been developed for diagnostic protein discovery, which combines proteolytic digestion of fractionated plasma proteins and liquid chromatography coupled to electrospray time-of-flight mass spectrometry (LC/ESI-TOFMS) profiling. Proteolysis prior to profiling overcomes molecular weight limitations and compensates for the poor sensitivity of matrix-assisted laser desorption/ionization (MALDI) protein profiling. LC/MS increases the peak capacity compared to crude fractionation techniques or single sample MALDI analysis. Differentially expressed peptides are targeted in the mass chromatograms using bioinformatic techniques and subsequently sequenced with MALDI tandem MS. In a model study comparing pancreatic cancer patients to controls, 74% of the peptide targets were successfully sequenced. This profiling method was superior to previous experiments using single sample MALDI analysis for protein profiling or proteolytic peptide profiling, because more potential protein markers were identified.

Adult↗

PubMed2005

AURKA amplification, chromosome instability, and centrosome abnormality in human pancreatic carcinoma cells.

To test the hypothesis that AURKA amplification contributes to pancreatic tumorigenesis by increasing centrosome abnormality and chromosome instability, the current study explored the associations between AURKA amplification, chromosome instability, centrosome abnormality, and the expression of several important proteins that are involved in cell proliferation (Ki-67), cell cycle regulation (p53, p16), and apoptosis (survivin) in 12 human pancreatic carcinoma cell lines. Using fluorescence in situ hybridization (FISH), we observed that 5 of the 12 cell lines had an AURKA amplification index (AI) (percentage of cells with more than three signals) >60%. Both the AURKA AI and the average number of signals per cell (ANSPC) were significantly associated with the copy number of chromosome 9 but not chromosome 17. The AURKA ANSPC was positively associated with the percentage of cells with the centrosome abnormality. Furthermore, centrosome abnormality was significantly associated with the frequency of cells with abnormal nuclei and abnormal mitotic figures, but no direct association was detected between the frequency of centrosome abnormalities and chromosome instabilities. The AURKA AI was also associated with a lower expression of Ki-67, a higher expression of survivin, and the lack of expression of p16. These associations support our hypothesis that AURKA amplification contributes to pancreatic carcinogenesis by increasing chromosome instability and centrosome abnormality.

Aurora Kinase A↗