Expression of breast cancer resistance protein (BCRP/ABCG2) in human placenta throughout gestation and at term before and after labor

Breast cancer resistance protein, BCRP, is a multidrug resistance protein that is highly expressed in the human placenta. In cancer tissues, this protein actively extrudes a wide variety of chemically and structurally unrelated chemotherapeutic drugs and other compounds. Studies in mice have shown that in the absence of BCRP activity in the placenta, there is a 2-fold increase in the uptake in BCRP substrates into fetus. This suggests that in the placenta, BCRP extrudes compounds that would otherwise cross the syncytiotrophoblast cells into fetal circulation. The purpose of this study was to examine the expression and localization of BCRP in the human placenta throughout gestation. Tissues from 6–13, 16–19, 24–29, 32–35, and 38–41 weeks of gestation were used. Real time RT-PCR analysis demonstrated that the mRNA levels of BCRP in the placenta do not change significantly as gestation progressed. However, Western blot analysis revealed that the protein levels increased towards the end of gestation. We demonstrated that BCRP is localized to the syncytiotrophoblast of the placenta and in some fetal blood vessels within the placenta. Tissues from the early stages of pregnancy (6–13 weeks) showed fewer BCRP positive blood vessels than term tissues (38–41 weeks).

Microsatellites, single nucleotide polymorphisms and a sequence tagged site in starch-synthesizing genes in relation to starch physicochemical properties in nonwaxy rice (Oryza sativa L.)

Starch characteristics determine the quality of various products of rice, e.g., eating, cooking and processing qualities. Our previous study indicated that molecular markers inside or close to starch synthesizing genes can differentiate the starch properties of 56 waxy rices. Here we report microsatellite (or simple sequence repeat, SSR) polymorphism in the Waxy (Wx) gene, soluble starch synthase I gene (SS1) and starch branching enzyme 1 gene (SBE1), single nucleotide polymorphism (SNP) in Wx and starch branching enzyme 3 gene (SBE3), and a sequence tagged site (STS) in starch branching enzyme 1 gene (SBE1) among 499 nonwaxy rice samples and their relationships with starch physicochemical properties. The nonwaxy rice samples consist of landraces (n = 172) obtained from germplasm centers and cultivars and breeding lines (n = 327) obtained from various breeding programs. Ten (CT)( n ) microsatellite alleles, (CT)(8), (CT)(10), (CT)(11), (CT)(12, )(CT)(17), (CT)(18), (CT)(19), (CT)(20), (CT)(21), and (CT)(22), were found at the Wx locus, of which (CT)(11) was the most frequent, and (CT)(12), (CT)(21) and (CT)(22) were identified for the first time. Four (CT)( n ) microsatellite alleles were found at the SBE1 locus, (CT)(8), (CT)(9), and (CT)(10 )together with an insertion sequence of CTCTCGGGCGA, and (CT)(8) alone without the insertion, of which (CT)(9) and the insertion was a new allele identified in only one rice, IR1552. Multiple microsatellites clustered at the SS1 locus, and in addition to the three alleles previously detected (SSS-A = (AC)(2)...TCC(TC)(11)...(TC)(5)C(ACC)(11), SSS-B = (AC)(3)...TCT(TC)(6)...(TC)(4)C(ACC)(9), and SSS-C = (AC)(3)...TCT(TC)(6)...(TC)(4)C(ACC)(8)), one new allele (SSS-D = (AC)(2)...TCC(TC)(10)...(TC)(4)C(ACC)(9)) was found. Analysis of the starch physicochemical properties of the samples with different microsatellites, SNPs and STS groups indicated that these molecular markers can differentiate almost all the physicochemical properties examined, e.g., apparent amylose content (AAC), pasting viscosity characteristics, and gel textural properties. Wx SSR and Wx SNP alone explained more variations for all physicochemical properties than the other molecular markers. The total six markers could explain 92.2, 81 and 86% of total variation of AAC, gel hardness (HD), and gel cohesiveness (COH), respectively, and they could explain more than 40% of the total variation of hot paste viscosity (HPV), cool paste viscosity (CPV), breakdown viscosity (BD), setback viscosity (SB) and gel adhesiveness (ADH). However, only 29% of the total variation of peak viscosity (PV) and 37% of pasting temperature (PT) could be explained by all the molecular markers. Some of these markers can differentiate the starch physicochemical properties among the rice samples with the same Wx allele, indicating that the variation within Wx allele classes can be explained by other starch synthesizing genes. These SSRs, SNPs and STS are useful in marker-assisted breeding for the improvement of starch quality of rice.

Nucleotide diversity in starch synthase IIa and validation of single nucleotide polymorphisms in relation to starch gelatinization temperature and other physicochemical properties in rice (Oryza sativa L.)

The characteristics of starch, such as gelatinization temperature (GT), apparent amylose content (AAC), pasting temperature (PT) and other physicochemical properties, determine the quality of various products of rice, e.g., eating, cooking and processing qualities. The GT of rice flour is controlled by the alk locus, which has been co-mapped to the starch synthase IIa (SSIIa) locus. In this study, we sequenced a 2,051 bp DNA fragment spanning part of intron 6, exon 7, intron 7, exon 8 and part of 3' untranslated region of SSIIa for 30 rice varieties with diverse geographical distribution and variation in starch physicochemical properties. A total of 24 single nucleotide polymorphisms (SNPs) and one insertion/deletion (InDel) were identified, which could be classified into nine haplotypes. The mean pairwise nucleotide diversity pi was 0.00292, and Watterson's estimator theta was 0.00296 in this collection of rice germplasm. Tajima's D test for selection showed no significant deviation from the neutral expectation (D = - 0.04612, P > 0.10). However, significant associations were found between seven of the SNPs and peak GT (T (p)) at P < 0.05, of which two contiguous SNPs (GC/TT) showed a very strong association with T (p) (P < 0.0001). With some rare exception, this GC/TT polymorphism alone can differentiate rice varieties with high or intermediate GT (possessing the GC allele) from those with low GT (possessing the TT allele). In contrast, none of these SNPs or InDel was significantly associated with amylose content. A further 509 rice varieties with known physicochemical properties (e.g., AAC and PT) and known alleles of other starch synthesizing genes were genotyped for the SSIIa GC/TT alleles. Association analysis indicated that 82% of the total variation of AAC in these samples could be explained by a (CT)n simple sequence repeat (SSR) and a G/T SNP of Waxy gene (Wx), and 62.4% of the total variation of PT could be explained by the GC/TT polymorphism. An additional association analysis was performed between these molecular markers and the thermal and retrogradation properties for a subset of 245 samples from the 509 rice varieties. The SSIIa GC/TT polymorphism explained more than 60% of the total variation in thermal properties, whereas the SSR and SNP of Wx gene explained as much as the SSIIa GC/TT of the total variation in retrogradation properties. Our study provides further support for the utilization of the GC/TT polymorphism in SSIIa. As shown in our study of 509 rice varieties, the GC/TT SNP could differentiate rice with high or intermediate GT from those with low GT in about 90% of cases. Using four primers in a single PCR reaction, the GC/TT polymorphism can be surveyed on a large scale. Thus, this SNP polymorphism can be very useful in marker-assisted selection for the improvement of GT and other physicochemical properties of rice.

Recombinant adenoviruses expressing TRAIL demonstrate antitumor effects on non-small cell lung cancer (NSCLC)

INTRODUCTION

Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) induces apoptosis in a variety of malignant cells, but not in normal cells. This preferential toxicity to the abnormal cells renders TRAIL potentially a very powerful therapeutic weapon against cancer. However, a requirement for large quantities of TRAIL to suppress tumor growth in vivo is one of the major factors that has hindered it from being widely applied clinically. To overcome this, we constructed a replication-deficient adenovirus that carries a human full-length TRAIL gene (Ad-TRAIL) and tested its efficacy against a lung cancer model system in comparison to that of the recombinant soluble TRAIL protein.

METHODS

To investigate the antitumor activity and therapeutic value of the Ad-TRAIL on the non-small cell lung cancer (NSCLC), four NSCLC cell lines, namely, YTMLC, GLC, A549, and H460 cells, were used. TRAIL protein expression was determined by Western blotting and flow cytometry. Cell viability was analyzed by proliferation assay, and DNA ladder and cell-cycle analysis were used to identify apoptosis. To further evaluate the effect of Ad-TRAIL in vivo, YTMLC cells were inoculated to the subcutis of nude mice. The Ad-TRAIL was subsequently administered into the established tumors. Tumor growth and the TRAIL toxicity were evaluated after treatment.

RESULTS

YTMLC cells infected with Ad-TRAIL showed decreased cell viability and a higher percentage of apoptosis. Similar, Ad-TRAIL treatment also significantly suppressed tumor growth in vivo.

CONCLUSIONS

TRAIL gene therapy provides a promising therapy for the treatment of NSCLC.

c-Jun N-terminal kinase is activated in non-small-cell lung cancer and promotes neoplastic transformation in human bronchial epithelial cells

c-Jun N-terminal kinase (JNK) has been reported to either potentiate or inhibit oncogenesis, depending upon the cellular context, but its role in lung neoplasia is unclear. Here we sought to define the role of JNK in lung neoplasia by examining evidence of JNK phosphorylation in non-small-cell lung cancer (NSCLC) biopsy samples and by using genetic and pharmacologic approaches to modulate JNK expression and activity in cultured cells. Immunohistochemical staining for JNK phosphorylation was detected in 114 (45%) of 252 NSCLC biopsy samples and was predominantly nuclear, providing evidence of JNK activation in a subset of NSCLC cases. Introduction of a doxycycline-inducible, constitutively active, mutant mitogen-activated protein kinase kinase 4 (MKK4) into the human bronchial epithelial cell lines BEAS-2B and HB56B increased the cells' proliferation, migration, invasion and clonogenicity. Depletion of JNK in MKK4 mutant-transformed BEAS-2B cells by introduction of JNK1/2 short hairpin RNA reversed the transformed phenotype, indicating that JNK activation is oncogenic and MKK4 confers neoplastic properties in these cells. The proliferation of NSCLC cell lines HCC827 and H2009, in which JNK and its substrate c-Jun are constitutively phosphorylated, was inhibited by SP600125, a JNK kinase inhibitor. We conclude that JNK is activated in a subset of NSCLC biopsy samples and promotes oncogenesis in the bronchial epithelium, suggesting that strategies to inhibit the JNK pathway should be considered for the prevention and treatment of NSCLC.

On the human CYP2C9*13 variant activity reduction: a molecular dynamics simulation and docking study

Cytochrome P450 2C9 (CYP2C9) plays a key role in the metabolism of clinical drugs. CYP2C9 is a genetically polymorphic enzyme and some of its allelic variants have less activity compared to the wild-type form. Drugs with a narrow therapeutic index may cause serious toxicity to the individuals who carry such allele. CYP2C9*13, firstly identified by some of the present authors in a Chinese poor metabolizer of lornoxicam, is characterized by mutation encoding Leu90Pro substitution. Kinetic experiments show that CYP2C9*13 has less catalytic activity in elimination of diclofenac and lornoxicam in vitro. In order to explore the structure-activity relationship of CYP2C9*13, the three-dimensional structure models of the substrate-free CYP2C9*1 and its variant CYP2C9*13 are constructed on the basis of the X-ray crystal structure of human CYP2C9*1 (PDB code 1R9O) by molecular dynamics simulations. The structure change caused by Leu90Pro replacement is revealed and used to explain the dramatic decrease of the enzymatic activity in clearance of the two CYP2C9 substrates: diclofenac and lornoxicam. The trans configuration of the bond between Pro90 and Asp89 in CYP2C9*13 is firstly identified. The backbone of residues 106-108 in CYP2C9*13 turns over and their side chains block the entrance for substrates accessing so that the entrance of *13 shrinks greatly than that in the wild-type, which is believed to be the dominant mechanism of the catalytic activity reduction. Consequent docking study which is consistent with the results of the kinetic experiments by Guo et al. identifies the most important residues for enzyme-substrate complexes.

Two novel mutations and evidence for haploinsufficiency of the ADAR gene in dyschromatosis symmetrica hereditaria

BACKGROUND

Dyschromatosis symmetrica hereditaria (DSH, MIM 127400) is a dominantly inherited skin disease associated with mutations in ADAR, the gene that encodes a double-stranded RNA-specific adenosine deaminase. We previously reported two novel ADAR mutations (p.Q513X and p.R916W) and confirmed the role of ADAR in Chinese patients with DSH. Both haploinsufficiency and a dominant-negative effect have been suggested as the potential mechanism by which ADAR mutations cause DSH.

OBJECTIVES

To identify ADAR mutations in two additional Chinese DSH families and to obtain insight into the pathogenic mechanism of heterozygous ADAR mutations.

METHODS

For mutation detection, all ADAR exons and their flanking intronic sequences were amplified and sequenced. Mutations were further confirmed by restriction analysis. Direct sequencing of cDNA fragments produced by reverse transcription-polymerase chain reaction (RT-PCR) and real-time quantitative RT-PCR were used to examine the expression of ADAR in peripheral lymphocytes isolated from affected individuals.

RESULTS

A small deletion, c.1555delT (p.C519fs), and a missense mutation, c.3116A>G (p.K1039R), were found in families A and B, respectively. In individuals carrying p.Q513X or p.C519fs, sequencing of cDNA fragments indicated almost total loss of mRNA expression from the mutant alleles, and real-time quantitative RT-PCR showed an approximately 50% reduction of ADAR expression. However, equal abundance of the wild-type and mutant cDNA sequences without reduction of ADAR expression was found in a patient with the missense p.R916W mutation. These results suggest that both the nonsense p.Q513X and frameshift p.C519fs mutations have generated null alleles probably by nonsense-mediated mRNA decay.

CONCLUSIONS

Two novel ADAR mutations were found in Chinese patients with DSH. Evidence for ADAR haploinsufficiency as a mechanism underlying the molecular pathogenesis of DSH was obtained.

The relationship between polymorphisms of HCMV UL144 ORF and clinical manifestations in 73 strains with congenital and/or perinatal HCMV infection

Human cytomegalovirus (HCMV) displays genetic variability and can cause a wide range of diseases in neonates. To explore the relationship between polymorphisms and clinical manifestations, the UL144 genes from 73 clinical strains were sequenced. All of the strains, which came from 70 infants with suspected congenital and/or perinatal HCMV infection, were non-passage strains. Among them, 23 strains were from surgery specimens, and the others were from urine samples. Clinically, 12 infants displayed asymptomatic infection and 58 patients displayed symptomatic infection. The results showed that 36 patients (49.3%) were infected with strains belonging to UL144 group G1 (G1a 33/36, G1b 3/36), 19 patients (28.8%) were infected with strains belonging to group G2, and 15 patients (21.9%) were infected with strains belonging to group G3. This result indicated that UL144 group G1 was the predominant genotype in congenital and/or perinatal HCMV infection in northern China. Compared with the distribution pattern of strains in UL144 genotypes of data from Chicago, Iowa and Texas, and Japan by chi-square test, the difference was statistically significant. This suggested that the distribution pattern of strains in UL144 genotype was related to geographic location. However, no linkage was observed between the UL144 genotypes and the severity and/or outcome of HCMV disease.

Characterization of microsatellite loci in fulvous fruit bat Rousettus leschenaulti

Rousettus leschenaulti is an abundant species in many countries of South‐East Asia, including south China. We isolated seven microsatellite loci in R. leschenaulti from genomic DNA enriched for CA repeats with the enriched library method. A total of 56 samples from a population in the Guangxi Province of China were tested with these microsatellite markers. The polymorphism ranged from seven to 16 alleles, and the observed heterozygosity was 84–94%. It is the first time microsatellite markers were characterized from R. leschenaulti, and these markers can be an important tool for analysing population structure and genotypic diversity.

The specificity of Sushi peptides for endotoxin and anionic phospholipids: potential application of POPG as an adjuvant for anti-LPS strategies

Sushi peptides [S1 (Sushi 1 peptide) and S3] are derived from the LPS (lipopolysaccharide; also known as endotoxin)-binding domains of an LPS-sensitive serine protease, Factor C, from the horseshoe crab (Carcinoscorpius rotundicauda). S1 and S3 interact at high affinity with LPS. The intermolecular disulphide bonding in the S3 dimer is indispensable for its LPS binding, disruption and consequent neutralization. Simultaneously, the specific interaction between the Sushi peptides and bacterial membrane phospholipids further explains the selective propensity of these peptides for the gram-negative bacteria. Our findings yield insights into a complex molecular paradigm in which the juxtaposition of LPS molecules and the anionic phospholipid POPG (1-palmitoyl-2-oleoyl phosphatidylglycerol) on the bacterial outer membrane confers such interfacial properties which create the optimal environment for the interaction between the peptides and bacterial membrane lipids.

Vegetative insecticidal protein enhancing the toxicity of Bacillus thuringiensis subsp kurstaki against Spodoptera exigua

AIMS

The objective of this work was to enhance the insecticidal activity or widen the pesticidal spectrum of a commercial Bacillus thuringiensis strain YBT1520.

METHODS AND RESULTS

A vegetative insecticidal protein gene vip3Aa7, under the control of its native promoter and cry3A promoter, was subcloned into B. thuringiensis acrystalliferous BMB171 to generate BMB8901 and BMBvip respectively. It was found that the amount of Vip3Aa7 protein produced by BMBvip was 3.2-fold more than that produced by BMB8901. Therefore, the vip3Aa7 gene under the control of cry3A promoter was transformed into strain YBT1520. The toxicity of the resulting strain BMB218V against Spodoptera exigua was 10-fold more than that of YBT1520, and that the toxicity of BMB218V against Helicoverpa armigera retained the same level as that of strain YBT1520.

CONCLUSIONS

Strain YBT1520 obtained high toxicity against S. exigua after it was transformed and expressed the foreign vip3Aa7 gene.

SIGNIFICANCE AND IMPACT OF THE STUDY

Commercial B. thuringiensis strain YBT1520 has high toxicity against H. armigera and Plutella xylostella, but almost no activity against S. exigua, which is a major crop pest in China. This work provides a new strategy for widening the activity spectrum of B. thuringiensis against agriculture pests.

Upregulation and activation of PKC alpha by ErbB2 through Src promotes breast cancer cell invasion that can be blocked by combined treatment with PKC alpha and Src inhibitors

Although ErbB2 is known to enhance breast cancer metastasis, the signaling events responsible for this remain elusive. Alpha-isozyme of protein kinase C (PKCalpha), which is involved in cancer development and progression, has been suggested to be activated by ErbB2 without direct evidence. In addition, the roles of PKCalpha in ErbB2-mediated cancer cell malignancy have not been clearly identified. In this study, we investigated whether ErbB2 can activate PKCalpha and determined what role PKCalpha plays in ErbB2-mediated breast cancer cell invasion. We expressed wild-type and mutant ErbB2 with altered signaling capacities in MDA-MB-435 breast cancer cells and revealed that overexpression or activation of ErbB2 in MDA-MB-435 cells upregulated and activated PKCalpha and that downregulation of ErbB2 by small-interfering RNA decreased the expression and activity of PKCalpha in BT474 breast cancer cells. These in vitro results were supported by data from breast cancer patient samples. In 150 breast cancer tumor samples, ErbB2-overexpressing tumors showed significantly higher positive rates of PKCalpha membrane immunohistochemistry staining than that of ErbB2-low-expressing tumors. Mechanistically, we found that PKCalpha is co-immunoprecipitated with Src and PKCalpha expression and activity can be decreased by Src inhibitor PP2 and by the expression of a dominant-negative mutant of Src. Moreover, ErbB2-mediated upregulation of urokinase-type plasminogen activator receptor (uPAR) is reduced by either the PKCalpha inhibitor Go6976 or the Src inhibitor PP2, and the combination of Go6976 with PP2 is superior to either agent alone in suppressing uPAR expression and cell invasion. These results demonstrate that PKCalpha is critical for ErbB2-mediated cancer cell invasion and provide valuable insights for current and future PKCalpha and Src inhibitor clinical trials.

Energy balance in Alzheimer's disease

Alzheimer s disease is the most frequent cause of dementia in elderly people and it is one of the leading causes of death among older individuals. Weight loss is a frequent clinical finding in Alzheimer s disease patients, and it is actually listed as a symptom consistent with the diagnosis of Alzheimer s disease, but its significance has not been clearly understood until now. This review examines the role of the components of energy balance in determining weight loss in AD patients, on the basis of data collected from the literature. We also considered the possible causes of anorexia in AD patients. In the last years many researchers investigated the possible role of abnormally high energy expenditure, or low energy intakes, or both, to explain weight loss in these patients. Studies on energy intake, energy expenditure and body composition in AD patients have been reviewed. The results of published studies do not seem to support the hypothesis of an hypermetabolic state or inadequate energy intake in AD patients, but further studies, with greater samples are necessary in the future to investigate weight loss in AD patients. A better understanding of this finding could be important to obtain the maximal lifespan of demented patients.

Cloning and expression of mel gene from Bacillus thuringiensis in Escherichia coli

Previous work from our laboratory has shown that most of Bacillus thuringiensis strains possess the ability to produce melanin in the presence of L -tyrosine at elevated temperatures (42 degrees C). Furthermore, it was shown that the melanin produced by B. thuringiensis was synthesized by the action of tyrosinase, which catalyzed the conversion of L -tyrosine, via L -DOPA, to melanin. In this study, the tyrosinase-encoding gene (mel) from B. thuringiensis 4D11 was cloned using PCR techniques and expressed in Escherichia coli DH5 alpha. A DNA fragment with 1179 bp which contained the intact mel gene in the recombinant plasmid pGEM1179 imparted the ability to synthesize melanin to the E. coli recipient strain. The nucleotide sequence of this DNA fragment revealed an open reading frame of 744 bp, encoding a protein of 248 amino acids. The novel mel gene from B.thuringiensis expressed in E. coli DH5 alpha conferred UV protection on the recipient strain.

Expression of the multidrug resistance P-glycoprotein, (ABCB1 glycoprotein) in the human placenta decreases with advancing gestation

The multidrug resistance p-glycoprotein (P-gp), encoded by the ABCB1 gene, is a plasma membrane protein that actively extrudes a wide variety of substances from cells. Preliminary studies in mice have shown that the ABCB1/P-gp can protect the fetus from a number of toxic substances. ABCB1/P-gp is expressed in the human placenta and is potentially capable of protecting the fetus from a large number of drugs and toxins, including herbicides and pesticides. The protein can also extrude various steroids including certain glucocorticoids and may therefore play an important role in regulating fetal access of glucocorticoids. The aim of the present study was to examine the expression profile and cellular localization of ABCB1/P-gp in human placenta throughout gestation. We hypothesized that there would be gestational age-related changes in the expression of the protein. ABCB1/P-gp mRNA was measured by Real-Time PCR using specific probes in tissues obtained from 6 weeks gestation to term. ABCB1/P-gp mRNA levels in placental tissue obtained at 6-10 weeks (n=5) and 24-35 weeks (n=5) were significantly higher than in tissues obtained at term (38-41 weeks gestation) by elective C-section (n=6) or following labor (n=6). The profile of ABCB1/P-gp protein levels, quantified using Western analysis, demonstrated a similar decrease with advancing gestation. At all gestational ages ABCB1/P-gp was localized by immunohistochemistry to the syncytiotrophoblast. In term tissues, it appeared to be localized to some areas of the villi and not others. Together, these data indicate that with advancing gestation there is a decrease in the level of ABCB1/P-gp in the human placenta indicating that the fetus may be more susceptible to toxic insults in the latter part of gestation. Further, the reduction in ABCB1/P-gp expression may contribute to the increased transfer of maternal cortisol to the fetus that is known to occur in late gestation.