RUNX2 Reverses p53-Induced Chemotherapy Resistance in Gastric Cancer

Objective

Gastric cancer is one of the most common malignancies worldwide; however, its overall mortality has not improved significantly over the last decade. Chemoresistance plays a critical role in this issue. This study aimed to clarify the role and mechanism of runt-related transcription factor 2 (RUNX2) in platinum-based chemotherapy resistance.

Methods

First, a drug-resistant model of gastric cancer cells was established to evaluate the relative expression level of the RUNX2 as a potential biomarker of chemotherapy resistance. Next, exogenous silencing was conducted to study whether RUNX2 could reverse drug resistance and understand the underlying mechanisms. Simultaneously, the correlation between the clinical outcomes of 40 patients after chemotherapy and the RUNX2 expression levels in tumor samples was analyzed.

Results

We discovered that RUNX2 was significantly expressed in drug-resistant gastric cancer cells and tissues; it was also reversibly resistant to transformation treatment by exogenous RUNX2 silencing. It is confirmed that RUNX2 negatively regulates the apoptosis pathway of the p53 to reduce the chemotherapeutic effects of gastric cancer.

Conclusion

RUNX2 is a possible target for platinum-based chemotherapy resistance.

Effects of linalool on Botrytis cinerea growth and control of tomato gray mold

We examined the antifungal characteristics of linalool against Botrytis cinerea using plate inhibition assay and spore germination assay, and assessed the capacity of linalool in controlling tomato gray mold disease via tomato pot inoculation assay. The results showed that linalool exhibited strong inhibitive effects on mycelial growth of B. cinerea, with an EC₅₀ value of 0.581 mL·L^-1. In the spore germination test, linalool treatment inhibited spore germination in a dose-dependent manner. The electric conductivity and the malondialdehyde (MDA) contents were significantly increased in linalool-treated B. cinerea than that of the control, indicating that linalool induced oxidative damage and destroyed the cell membrane integrity in B. cinerea. The activities of the superoxide dismutase (SOD), catalase (CAT), and peroxidase (POD) in the linalool-treated B. cinerea were decreased significantly by 27.4%, 68.9% and 26.0%, respectively, suggesting that linalool inhibited the antioxidant activity of B. cinerea. In the pot experiment, the diameter of lesions in linalool-treated tomatoes was significantly smaller than that of the control. The activities of SOD, POD, CAT, polyphenol oxidase, and phenylalnine ammonialyase in the linalool-treated tomatoes increased, while the MDA content decreased, suggesting that linalool could alleviate the oxidative damage caused by B. cinerea and promote plant disease resistance. In summary, linalool had inhibitory effect on the growth of B. cinerea and could control gray mold disease in tomatoes. These findings could lay the foundation for developing bota-nical antifungal agents for management of tomato gray mold disease.

[A cross-sectional survey of receiving no methadone maintenance treatment in HIV infected injecting drug users in Dehong Dai and Jingpo autonomous prefecture, Yunnan province]

Objective: To understand the current status of receiving no methadone maintenance treatment (MMT) and influencing factors in HIV infected injecting drug users (IDUs) in Dehong Dai and Jingpo autonomous prefectures, Yunnan province. Methods: Data of survival of IDUs with AIDS in Dehong were collected from " Chinese National Comprehensive HIV/AIDS and Care Information System" in December, 2014. Results: There were 987 IDUs who should receive MMT, the majority of them were males (94.6%, 934/987), aged 35-44 years (53.0%, 523/987) and farmers (77.2%, 762/987). Among the 987 IDUs, 60.2% (592/987) received no MMT. Multivariate logistic regression analysis showed that being female (OR=2.66, 95%CI: 1.21-5.87), in Jingpo ethnic group (OR=3.05, 95% CI: 1.97-4.71) were the major risk factors for receiving no MMT; not being farmers (OR=0.46, 95%CI: 0.31-0.70), in Dai ethnic group (OR=0.53, 95%CI: 0.36-0.79), diagnosed HIV infection history ≥10 years (OR=0.60, 95%CI: 0.45-0.81) were the major protective factors for receiving no MMT. The reasons for receiving no MMT included long distance journey (289, 48.8%), fear of exposure (124, 20.9%), poor daily medication compliance (59, 10.0%), fear of side effects (47, 7.9%), others (73, 12.3%). Conclusions: The proportion of receiving no MMT in IDUs with AIDS in Dehong was high. Being female and farmer, in Jingpo ethnic group, low educational level, short diagnosed HIV infection history were influencing factors for receiving no MMT. The effective intervention measures should be taken to further improve MMT coverage according to the different characteristics of the patients.

Club drug use and associated high-risk sexual behaviour in six provinces in China

AIM

To investigate the characteristics of the different club drugs and associated high-risk sexual behaviours in China.

DESIGN

Multicentre cross-sectional study.

SETTING

Drug Detoxification and Rehabilitation Centres in six provinces, China.

PARTICIPANTS

A total of 1434 eligible club drug users were included.

MEASUREMENTS

Participants were investigated by trained interviewers using a self-designed structured questionnaire to collect information on club drug use and associated behaviours.

FINDINGS

Methamphetamine was the most commonly abused drug in participants (73.92%), who used it in their or their friends' homes by non-injection for the purpose of feeling euphoria. Among participants with sexual behaviours after club drug use, 75.21% reported having engaged in sex with multiple partners after club drug use during the past year and 79.84% had unprotected sex after using club drug during the past year. A two-level logistic model showed that male gender [adjusted odds ratio (AOR)=7.14; 95% confidence interval (CI)=4.17-12.5], unmarried (AOR=1.71, 95% CI=1.04-2.79), long duration of club drug use during their life-time (AOR=1.76, 95% CI=1.28-2.42) and severe acute intoxication after using club drugs during the past year (AOR=2.11, 95% CI=1.07-4.15) were independent risk factors of multiple sex partners during the past year. Another two-level model showed that the club drug users who were female (AOR=1.79, 95% CI=1.03-3.11) and had polydrug use during their lifetime (AOR=1.55, 95% CI=1.01-2.34) had more risk for unprotected sex during the past year than without these characteristics.

CONCLUSION

High-risk sexual behaviours are common among club drug users in China. The prevention and intervention of club drug use could decrease the risk of sexual behaviours which further prevent HIV transmission and other sexually transmitted infections in China.

Metabolic responses to ethanol in Saccharomyces cerevisiae using a gas chromatography tandem mass spectrometry-based metabolomics approach

During the fermentation process, Saccharomyces cerevisiae cells are often inhibited by the accumulated ethanol, and the mechanism of the S. cerevisiae response to ethanol is not fully understood. In the current study, a systematic analytical approach was used to investigate the changes in the S. cerevisiae cell metabolome that were elicited by treatment with various concentrations of ethanol. Gas chromatography-mass spectrometry and a multivariate analysis were employed to investigate the ethanol-associated intracellular biochemical changes in S. cerevisiae. The intracellular metabolite profiles that were found upon treatment of the cells with different concentrations of ethanol were unique and could be distinguished with the aid of principal component analysis. Furthermore, partial least-squares-discriminant analysis revealed a group classification and pairwise discrimination between the control without ethanol and ethanol treated groups, and 29 differential metabolites with variable importance in the projection value greater than 1 were identified, which was also confirmed by the subsequent hierarchical cluster analysis. The metabolic relevance of these compounds in the response of S. cerevisiae to ethanol stress was investigated. Under ethanol stress, the glycolysis was inhibited and the use of carbon sources for fermentation was diminished, which might account for the growth inhibition of S. cerevisiae cells. It was suggested that S. cerevisiae cells change the levels of fatty acids, e.g., hexadecanoic, octadecanoic and palmitelaidic acids, to maintain the integrity of their plasma membrane through decreasing membrane fluidity in the medium containing ethanol. Moreover, the increased levels of some amino acids idemtified in the cells of ethanol-treated experimental group might also confer ethanol tolerance to S. cerevisiae. These results reveal that the metabolomics strategy is a powerful tool to gain insight into the molecular mechanism of a microorganism's cellular response to environmental stress factors.

Predictive factors for open conversion of laparoscopic adrenalectomy: a 13-year review of 456 cases

BACKGROUND AND PURPOSE

Laparoscopic adrenalectomy has largely replaced open adrenalectomy for the treatment of adrenal tumor. However, certain cases still require conversion to open procedures. Identifying the risk of conversion remains difficult. This study identified risk factors that may predict conversion from a laparoscopic to an open procedure.

PATIENTS AND METHODS

From January 1993 to September 2006, a total of 456 laparoscopic adrenalectomies were performed at two urologic centers. A retrospective analysis of parameters, including tumor size, patient age, American Society of Anesthesiology classification, body mass index (BMI), sex, laparoscopic approach, previous abdominal surgery, laterality, type of tumor, laparoscopist experience, and surgeon, was performed. Multivariate logistic regression was used to identify those variables predicting conversion.

RESULTS

A total of 25 (5.5%) laparoscopic adrenalectomies required conversion. Significant predictors of conversion according to univariate analysis were tumor size > or =5 cm, BMI > or =24 kg/m(2), and pheochromocytoma. Multivariate analysis showed that the significant independent predictive factors for conversion were tumor size > or =5 cm (8.884 greater odds ratio [OR] of conversion; 95% confidence interval 3.543, 22.277; P < 0.001), BMI > or = 24 kg/m(2) (OR 3.632; 95% confidence interval 1.367, 9.648; P = 0.010), and pheochromocytoma (OR 3.068; 95% confidence interval 1.175, 8.007; P = 0.022).

CONCLUSIONS

Knowledge of tumor size, BMI, and tumor type can help in counseling patients undergoing laparoscopic adrenalectomy with regard to the probability of conversion. The size of the tumor was found to be the most important predictor.

High frequency of level II-V lymph node involvement in RET/PTC positive papillary thyroid carcinoma

AIMS

To investigate the frequency and clinical significance of RET rearrangement in Chinese patients with papillary thyroid carcinoma (PTC) and discuss the role of RET rearrangement in therapeutic decision-making after the performance of level VI lymph node dissection and the 2002 AJCC staging system.

METHODS

RET/PTC-1 and RET/PTC-3 were detected in 126 PTCs using reverse transcription-polymerase chain reaction (RT-PCR) and direct sequencing.

RESULTS

RET rearrangement was detected in 18 cases of PTC. The patient group aged < 20 years had the highest frequency (3/6) of RET rearrangement among the age groups (< 20 years, 20-40 years and > or = 40 years; P=0.03). RET/PTC-1 positive patients were more likely to suffer from Hashimoto's thyroiditis simultaneously (P=0.02) while RET/PTC-3 positive patients had a higher frequency of extrathyroidal extension (P<0.01) and advanced T classification (P<0.01). RET rearrangement (OR=8.70, 95% CI 1.69-44.81), male (OR=3.88, 95% CI 1.41-10.69), age (OR=0.96, 95% CI 0.93-0.99), multifocality (OR=3.54, 95% CI 1.33-9.41) and advanced T classification (OR=7.32, 95% CI 2.91-18.40) were all identified as risk factors of level II-V lymph node involvement in the multivariate analysis.

CONCLUSIONS

The frequency of RET rearrangement in Chinese patients is low and age related. RET/PTC-1 and RET/PTC-3 are associated with different clinical pathological characteristics but not with lymph node involvement. The RET/PTC positive patients should receive more attention to lateral neck in the management of PTC.

Genetic dissection of ethanol tolerance in the budding yeast Saccharomyces cerevisiae

Uncovering genetic control of variation in ethanol tolerance in natural populations of yeast Saccharomyces cerevisiae is essential for understanding the evolution of fermentation, the dominant lifestyle of the species, and for improving efficiency of selection for strains with high ethanol tolerance, a character of great economic value for the brewing and biofuel industries. To date, as many as 251 genes have been predicted to be involved in influencing this character. Candidacy of these genes was determined from a tested phenotypic effect following gene knockout, from an induced change in gene function under an ethanol stress condition, or by mutagenesis. This article represents the first genomics approach for dissecting genetic variation in ethanol tolerance between two yeast strains with a highly divergent trait phenotype. We developed a simple but reliable experimental protocol for scoring the phenotype and a set of STR/SNP markers evenly covering the whole genome. We created a mapping population comprising 319 segregants from crossing the parental strains. On the basis of the data sets, we find that the tolerance trait has a high heritability and that additive genetic variance dominates genetic variation of the trait. Segregation at five QTL detected has explained approximately 50% of phenotypic variation; in particular, the major QTL mapped on yeast chromosome 9 has accounted for a quarter of the phenotypic variation. We integrated the QTL analysis with the predicted candidacy of ethanol resistance genes and found that only a few of these candidates fall in the QTL regions.

Constructing genetic linkage maps under a tetrasomic model

An international consortium has launched the whole-genome sequencing of potato, the fourth most important food crop in the world. Construction of genetic linkage maps is an inevitable step for taking advantage of the genome projects for the development of novel cultivars in the autotetraploid crop species. However, linkage analysis in autopolyploids, the kernel of linkage map construction, is theoretically challenging and methodologically unavailable in the current literature. We present here a theoretical analysis and a statistical method for tetrasomic linkage analysis with dominant and/or codominant molecular markers. The analysis reveals some essential properties of the tetrasomic model. The method accounts properly for double reduction and incomplete information of marker phenotype in regard to the corresponding phenotype in estimating the coefficients of double reduction and recombination frequency and in testing their significance by using the marker phenotype data. Computer simulation was developed to validate the analysis and the method and a case study with 201 AFLP and SSR markers scored on 228 full-sib individuals of autotetraploid potato is used to illustrate the utility of the method in map construction in autotetraploid species.

Modeling population genetic data in autotetraploid species

Allozyme and PCR-based molecular markers have been widely used to investigate genetic diversity and population genetic structure in autotetraploid species. However, an empirical but inaccurate approach was often used to infer marker genotype from the pattern and intensity of gel bands. Obviously, this introduces serious errors in prediction of the marker genotypes and severely biases the data analysis. This article developed a theoretical model to characterize genetic segregation of alleles at genetic marker loci in autotetraploid populations and a novel likelihood-based method to estimate the model parameters. The model properly accounts for segregation complexities due to multiple alleles and double reduction at autotetrasomic loci in natural populations, and the method takes appropriate account of incomplete marker phenotype information with respect to genotype due to multiple-dosage allele segregation at marker loci in tetraploids. The theoretical analyses were validated by making use of a computer simulation study and their utility is demonstrated by analyzing microsatellite marker data collected from two populations of sycamore maple (Acer pseudoplatanus L.), an economically important autotetraploid tree species. Numerical analyses based on simulation data indicate that the model parameters can be adequately estimated and double reduction is detected with good power using reasonable sample size.

Theoretical basis for genetic linkage analysis in autotetraploid species

Linkage analysis in autotetraploid species has been an historical challenge in quantitative genetics theory and is a stumbling block that urgently needs to be removed in the rapidly emerging genome research on this species, such as cultivated potato. This article presents theory of a full model of tetrasomic linkage and develops a statistical framework for the linkage analysis. The model considers both double reduction and recombination, the most essential features of tetrasomic inheritance with linked loci, whereas the statistical method takes appropriate account of the major complexities in analyzing both dominant and codominant molecular marker data during map reconstruction in tetraploid species. These complexities include the problems arising from multiple dosage of allelic inheritance, the null allele, allelic segregation distortion, mixed bivalent and quadrivalent pairing in meiosis, and incomplete information of marker phenotype data. The theoretical analysis established the relationship between the coefficients of double reduction at linked loci, which is essential in the present tetrasomic linkage analysis and in assessing the impact of double reduction on the evolution of tetraploid populations. The statistical method, based on the combination of theoretical analysis and a computer-based algorithm, provided analytical tools for predicting the maximum-likelihood estimates of the model parameters. A simulation study showed the feasibility of a practical implementation of the method, detailed the procedure of the analysis, validated the power and reliability in the parameter estimation, and compared the present method with those proposed in the current literature.

Factors governing selective formation of specific disulfides in synthetic variants of alpha-conotoxin

alpha-Conotoxin GI is a snail toxin protein consisting of 13 amino acids cross-linked by 2 intramolecular disulfide bridges. This toxin is an antagonist of acetylcholine receptors. The native sequence has been synthesized, along with nine additional variants in which non-cysteine residues are replaced by alanine or the cysteine positions are altered. Each reduced peptide has been oxidized by reaction with oxygen or glutathione both in a folding buffer and in 6 M guanidine hydrochloride. Purified products of oxidation have been characterized with respect to molecular weights and the positions of disulfides. The four cysteines in conotoxin can form two intramolecular disulfides in three different combinations. Relative yields of each of the three isomers have been determined, thereby permitting evaluation of the roles of non-cysteine residues and cysteine placements in the folding of conotoxin. Cysteine positions dominate factors directing formation of the nativelike isomer in a manner that may be predicted from equilibrium constants for loop formation in model peptides containing two cysteines. Alanine substitutions at several positions which are conserved in naturally occurring conotoxins affect the discrimination between the two most favored disulfide arrangements. Substitutions at three nonconserved positions have no structural effect on isomer yields. It therefore is possible to vary these latter three positions in a manner which might help to generate a functional binding surface which is complementary to receptors in the specific prey of a particular species of snail, without affecting the toxin's folding.

Dependence of formation of small disulfide loops in two-cysteine peptides on the number and types of intervening amino acids

Microscopic disulfide-exchange rate constants have been measured for the formation and opening of small disulfide loops in reactions between glutathione and peptides containing 2 cysteines. Twelve cysteine-Xm-cysteine peptides have been studied, where X is an amino acid and m is the number of amino acids between the cysteines. Homopolymers of alanine for m equaling 0-5 are evaluated, as well as X1 and X2 series employing glycine, valine, or proline. Equilibrium constants Kc for loop closing are only slightly dependent on the nature of X. Loops with even values of m generally are favored relative to loops with odd values. Kc increases in the rank order X1, X3, X0, X5, X4, and X2. Formation of a disulfide between sequentially adjacent cysteines therefore is not especially difficult. The dependence of Kc on the odd-even nature of m is compared with similar patterns observed both in statistics of disulfide formation in naturally occurring proteins and in theoretical studies of peptide cyclization. The relative equilibrium populations of intramolecular disulfides in peptides containing cysteine-cysteine-cysteine and cysteine-serine-cysteine-serine-cysteine clusters are consistent with predictions based on the values of Kc in the two-cysteine peptides.