Genetic polymorphisms of the sortase A gene and early childhood caries in two-year-old children

OBJECTIVE

To explore and compare the genetic polymorphisms of the sortase A (srtA) gene found in Streptococcus mutans (S. mutans) infecting two-year-old children suffering early childhood caries to those found in caries-free children through molecular identification methods.

METHODS

Clinical S. mutans strains were isolated from the dental plaques of two-year-old children. Fifteen strains of S. mutans from the caries-active group and 15 strains of S. mutans from the caries-free group were collected. Genomic DNA was extracted from the S. mutans isolates. DNA fragments, including the srtA gene, were amplified by PCR. The PCR products were purified, sequenced and analyzed. A chi-square test and BioEdit software were used to analyze the sequencing results.

RESULTS

All 30 clinically isolated S. mutans strains had a 741 base pair (bp) srtA gene. There were no nucleotide sequence insertions or deletions observed in the srtA genes. Twenty mutations were identified in the srtA genes that taken from the 30 clinical strains. There were 10 silent point mutations at the 78, 99, 150, 165, 186, 222, 249, 261, 312, and 636bp positions. The other 10 mutations were point mutations resulting in a missense mutation at the 23, 34, 36, 47, 112, 114, 168, 176, 470, and 671bp positions. None of the positions were enzyme-activity sites of srt A. The missense mutation rates of the two groups did not exhibit statistically significant differences.

CONCLUSION

There were no genetic polymorphisms of the sortase A gene associated with early childhood caries in two-year-old children.

Tranilast prevents the progression of chronic cyclosporine nephrotoxicity through regulation of transforming growth factor β/Smad pathways

PURPOSE

Our aim was to investigate the role of tranilast in transforming growth factor (TGF) β/Smad pathways using a rat model of chronic cyclosporine (CsA) nephrotoxicity.

METHODS

Thirty Sprague-Dawley (SD) rats were equally randomized in to 5 groups for gavage treatments daily for 4 weeks: normal control (N), olive oil; CsA (25 mg/kg), (M) CsA plus low-dose tranilast group (T1; CsA 25 mg/kg and tranilast 100 mg/kg); CsA plus medium-dose tranilast group (T2; CsA 25 mg/kg and tranilast 200 mg/kg); and CsA plus high-dose tranilast group (T4; CsA 25 mg/kg and tranilast 400 mg/kg). Kidneys were harvested at the end of the fourth week. TGF-β1 as well as Smad3 and Smad7 were detected by reverse-transcription polymerase chain reaction and immunohistochemistry.

RESULTS

The administration of tranilast decreased the expression of TGF-β1 and Smad3 by CsA-treated rats, whereas it increased both mRNA and protein levels of Smad7. Semiquantitative analysis of mRNA production revealed these treatments to markedly reduce the amount of TGF-β1: T1: 0.8452 ± 0.0825 vs 0.8529 ± 0.0606 (P < .05); T2: 0.8414 ± 0.0696 vs 0.8529 ± 0.0606 (P < .05); T4: 0.8336 ± 0.0592 vs 0.8529 ± 0.0606 (P < .05). For Smad3: T1: 0.8581 ± 0.0328 vs 0.8613 ± 0.0542 (P < .05); T2: 0.8528 ± 0.0599 vs 0.8613 ± 0.0542 (P < .05); T4: 0.8436 ± 0.0185 vs 0.8613 ± 0.0542 (P < .05). The significantly elevated dose-dependent amounts of Smad7 were: T1: 0.9026 ± 0.0522 vs 0.8678 ± 0.0246, (P < .05); T2: 0.9087 ± 0.0506 vs 0.8678 ± 0.0246 (P < .05); T4: 0.9151 ± 0.0793 vs 0.8678 ± 0.0246 (P < .05).

CONCLUSION

Regulation of TGF-β/Smad pathways is one of the mechanisims by which tranilast mitigates the progression of chronic CsA nephrotoxicity in rats.

Simultaneous determination of lincomycin and spectinomycin residues in animal tissues by gas chromatography-nitrogen phosphorus detection and gas chromatography-mass spectrometry with accelerated solvent extraction

A new multi-dimensional analytical method using gas chromatography-nitrogen phosphorus detection (GC-NPD) and gas chromatography-mass spectrometry (GC-MS) was developed for qualitative and quantitative measurement of lincomycin and spectinomycin residues in food animal tissues. This method is based on a new extraction procedure using accelerated solvent extraction (ASE). The analytes were extracted by phosphate buffer with trichloroacetic acid deproteinization and clean-up by C₁₈ solid-phase extraction (SPE) adding dodecanesulfonic acid sodium salt as an ion-pair reagent. The eluted fraction was evaporated and derivatised with N,O-bis(trimethylsilyl) trifluoroacetamide (BSTFA) for GC-NPD analysis and GC-MS confirmation. Parameters for extraction pressure, temperature and cycle of ASE, clean-up, derivatisation and analysis procedure were optimised. The method was validated in muscle, kidney and liver of swine, bovine with a low concentration (limit of quantification) of 16.4 and 21.4 µg kg⁻¹ for these two analytes using GC-NPD. For GC-MS, the limits of quantification were 4.1 and 5.6 µg kg⁻¹, respectively. Spiked recoveries from levels of 20 to 200 µg kg⁻¹ were found to be between 73% and 99% with a relative standard deviation (RSD) of less than 17% in GC-NPD. For GC-MS, levels from 5 to 20 µg kg⁻¹ had between 70% and 93% with an RSD of less than 21%. This rapid and reliable method can be used for the characterisation and quantification of residues of lincomycin and spectinomycin in animal tissues.

132 EFFECTS OF OXYGEN TENSION, MEDIUM, AND WELL OF THE WELL ON IN VITRO DEVELOPMENT OF THE MOUSE EMBRYO

The objectives of the present research were to investigate whether embryo culture media have preferences for oxygen tension, to explore the feasibility of using physical lung air to support the in vitro development of mouse embryos, and to evaluate the effect of well of the well (WOW) culture on in vitro preimplantational development of mouse embryos. The results are as follows. First, cleavage rate and blastocyst rate were not significantly different between medium CZB and mKSOM regardless of using 3 gas phases: 4% CO2 + 16% O2 + 78% N2 + 2% H2O (lung air), 5% CO2 + 5% O2 + 90% N2 (5% O2, low oxygen), and 5% CO2 + 95% air (20% O2, high oxygen; P > 0.05), but mean total cell numbers per blastocyst cultured in CZB medium were higher than those in mKSOM when the lung air was used (P < 0.05). Second, when mKSOM was used as the basic medium, the blastocyst rate (22.6%) in the 5% O2 gas phase was notably higher than that in other 2 gas phases (P < 0.05). Third, for the CZB medium, the blastocyst rate was not different significantly among 3 gas environments (P > 0.05). Fourth, both the blastocyst rate (74.6 ± 5.1%) and the mean total cell numbers per blastocyst (76 ± 2) cultured in the WOW system were obviously higher than those in the group culture system (38.2 ± 6.6% and 58 ± 4). Taken together, our results indicate that mKSOM and CZB have preferences for oxygen tension during in vitro culture of mouse embryos, the lung air was reaffirmed to be able to effectively support in vitro preimplantation development of mouse embryos, and the WOW culture system can apparently enhance in vitro developmental competence and blastocyst quality of mouse embryos. L. YS, C. ZB: equal contribution; supported by NSFC (30700574), 863 (2008AA101003).

250 HUMAN EXHALED AIR CAN EFFECTIVELY SUPPORT IN VITRO MATURATION OF PORCINE OOCYTES AND SUBSEQUENT IN VITRO DEVELOPMENT

The objective of the present study was to examine the feasibility of culturing porcine oocytes and embryos in vitro using the human exhaled lung air atmosphere. In Experiment 1, the effects of lung air atmosphere on nuclear maturation of prepubertal gilt oocytes and subsequent development in vitro of parthenogenetic-activated and somatic-cell-cloned embryos were explored. Abattoir-derived prepubertal gilt cumulus–oocyte complexes (COC) were matured in TCM-199 supplemented with 10 IU mL–1 of eCG, 10 IU mL–1 of hCG, 10 ng mL–1 of epidermal growth factor, and 10% porcine follicular fluid (pFF) for 40 to 44 h at 38.5°C, 100% humidity, and 5% CO2+20% O2 (high oxygen tension) or human exhaled air encapsulated in plastic, airtight bags (lung air) or 5% CO2+7% O2 (low oxygen tension) in the incubator. Nuclear maturation was evaluated by the presence of the 1st polar body. For parthenogenetic activation, denuded oocytes with the 1st polar body were selected and stimulated with a single 1.6-kV/cm, 100-μs direct current pulse followed by culture in porcine zygote medium-3. For NT, denuded metaphase II oocytes were enucleated, and then the donor cell was directly injected into the perivitelline space. After NT, reconstructed couplets were fused and activated electrically followed by treatment in 7.5 μg mL–1 of cytochalasin B and 10 μg mL–1 of cycloheximide for 4 to 6 h before culture in porcine zygote medium-3. We found no significant difference among groups in terms of nuclear maturation rate (66.5% v. 60.2%, 63.2%), cleavage rate (94.8% v. 94.2%, 85.2%), blastocyst formation rate (39.5% v. 40.3%, 32.5%), and total cell number (37 v. 38, 32). Moreover, as for porcine cloned embryo, no significant difference between the lung-air and high-oxygen (20% O2) groups was observed in the cleavage rate (88.3% v. 80.3%), blastocyst formation rate (7.3% v. 10.7%), and total cell number (34 v. 36). The above results indicated that porcine oocytes can be matured in vitro safely and efficiently using the human exhaled lung air atmosphere. In Experiment 2, in vitro developmental competence of porcine zona-free parthenogenetically activated embryos cultured in a lung air, low oxygen (5% O2), or high oxygen (20% O2) tension gas environment was studied. We found no obvious difference among the 3 groups regarding the rates of cleavage (83.0%, 83.6%, 82.8%), but blastocyst formation rate (26.8% v. 48.6%, 48.2%) and total cell number (23 v. 34, 29) in lung air were lower than those in the rest of the groups (P < 0.05). The results show that lung air could be an alternative for preparing a gas environment for in vitro culture of porcine zona-free parthenotes, although not an ideal alternative. Taken together, porcine oocytes and embryos can be cultured in vitro safely and efficiently using the human exhaled lung air atmosphere. Z. B. Cao and L. C. Sui contributed equally to this work. X. R. Zhang and Y. H. Zhang are the corresponding authors. This work was supported by NSFC (30700574), 863 (2008AA101003).

316 INDUCTION OF PIG INDUCED PLURIPOTENT STEM CELLS BY RECOMBINANT PROTEINS ENCODED BY DEFINED FACTORS

Pluripotent cells derived from any differentiated cell type through ectopic expression of transcription factors were designated as induced pluripotent stem (iPS) cells, exhibiting similar morphology and growth properties to embryonic stem (ES) cells besides expressing ES cell marker. Because iPS have the ability to differentiate into all types of cells, iPS cell technology is thought to have enormous potential for generating disease models, drug screening, toxicology, and regenerative medicine. However, for virus-mediated transfection of defined factors, the exogenous genes generally would be randomly inserted into the target cell’s genome, possibly bringing the potential hazard of insertional mutagenesis. Therefore, it is necessary to seek some new methods to induce somatic cell reprogramming without viruses. With instruction from the work of Zhou et al. (2009 Cell Stem Cell 4, 381–384), in the present study we attempted to use defined factors recombinant proteins-carried cell-penetrating peptide for the generation of porcine iPS cells, which would be a benefit for safe applications of iPS cells. Defined factors genes were amplified by PCR with specific primers of 9 arginines (R9) from recombinant plasmid pLL-hOCT4/pSox2/pMyc/pKlf4-EGFP (Yin et al. 2010 Prog. Biochem. Biophys. 37, 607–612) and inserted into prokaryotic expression vector pET-28a-EGFP. After DNA sequencing confirmation, the 4 recombinant plasmids were then transformed into BL21 strains, respectively. After IPTG induction, hOCT4/pSox2/pMyc/pKlf4-R9-EGFP fusion proteins were purified using Novagen His-Bind kit and confirmed by sodium dodecyl sulfate–polyacrylamide gel electrophoresis, respectively. Then, defined factors recombinant proteins were added into pig fetal fibroblasts (PFF) medium every 48 h to establish pig iPS cells. The results showed that purified hOCT4/pSox2/pMyc/pKlf4-R9-EGFP fusion proteins could enter into PFF efficiently, and most of them were located in nuclei. The PPF were subcultured in stem cell medium condition and treated with defined factors recombinant proteins for 6 cycles simultaneously; the clear-cut cell colonies were gradually derived. These cells had large translucent nuclei and a high nucleo:cytoplasmic ratio and were positive for AP, Oct4, and Nanog. Detailed characterisation of such induced cells is ongoing. This research would provide new ideas for the induction of porcine somatic cell reprogramming. Y. H. Zhang and H. G. Cao contributed equally. This work was supported by NSFC (30700574 30800784/c120103) and 973 (2009CB941004).

290 GENERATION OF INDUCED PLURIPOTENT STEM CELLS FROM BOVINE FETAL FIBROBLAST CELLS BY DEFINED FACTORS

Induced pluripotent stem cells (iPS) have broad potential applications in drug screening, regenerative medicine, and basic biology, and using iPS as starting materials that have identical properties to embryonic stem cell would probably revolutionize the production of gene-targeted livestock. However, iPS in livestock is still lacking except for in pigs. Instructed by Yamanaka’s idea, in the current study we attempted to generate bovine iPS from fetal fibroblast cells (bFF; from a fetus 2.5 months old after gestation) by using 4 defined transcriptional factors: Oct-4, Sox2, Klf4, and c-Myc. A lentivirus haboring the 4 factors acted as a vehicle to transfect the bFF. One bFF cell line was infected for at least 3 replicates. After transfection, the treated bFF were then cultured in DMEM supplemented with 4 ng mL–1 of basic fibroblast growth factor and 1000 IU mL–1 of leukemia inhibitory factor at 37.5°C, 5% CO2, on the mouse embryonic feeder cells pretreatd with mitomycin C. From Day 16 after the onset of induction, morphology of a few typical spindle-like bFF gradually changed into round, ball-like cells and grew into colonies. Afterward, when these colonies were harvested and subcultured in stem cell medium supplemented with 1000 IU mL–1 of leukemia inhibitory factor and 4 ng mL–1 of basic fibroblast growth factor, new colonies with clear-cut, round edge emerged, and the cells in the colonies had increased nuclear:cytoplasm ratio, kept normal karyotype up to 10 passages, and were alkaline phosphatase staining positive. We also found that the cells exhibited part of the stem cell markers, as evidenced by being Nanog, SSEA1 positive but SSEA3 and TRA-60 negative. Moreover, embryoid bodies could be formed in vitro, and terotoma formation after injection into nude mice also displayed 3 layers. Taken together, we found that 4 lentivirus-mediated, defined transcriptional factors could successfully induce bFF into iPS-like cells. H. G. Cao and Y. Liu contributed equally to this work. The corresponding authors are Y. H. Zhang and X. R. Zhang. This work was supported by NSFC (30800784/c120103, 30700574), 973 (2009CB941004).

The association and differentiation of MHC class I polymorphic Alu insertions and HLA-B/Cw alleles in seven Chinese populations

We investigated polymorphic Alu insertion (POALIN) frequencies at five loci in the major histocompatibility complex (MHC) class I genomic region to determine their allele and haplotype frequencies and associations with the human leukocyte antigen (HLA)-B and -Cw genes in seven different Chinese ethnic populations, the Han, Bulang, Wa, Dai, Maonan, Hani and Jinuo. The POALINs varied in frequency between 0% and 42.3% with significant differences between populations at all of the loci. Each POALIN was in significant linkage disequilibrium with a variety of HLA-B or -Cw four-digit alleles. The percentage association between Alu insertions and the HLA-B or -Cw alleles was calculated in pairwise analyses of haplotypes to show possible crossing over events between loci. The POALIN insertions also helped to further stratify the HLA-B:-Cw haplotypes into different POALIN:HLA-B:HLA-Cw haplotype frequencies. Of the two-locus, five-locus and seven-locus haplotype analyses, the seven-locus haplotypes showed the largest number of differences between the populations. The most common multilocus haplotype in Han was MICB*1:B*4601:Cw*0102:TF*1:HJ*1:HG*2:HF*1 (15.6%) associated with the AluHG insertion, whereas the second most common multilocus haplotype in Han was MICB*1:B*1502:Cw*0801:TF*1:HJ*2:HG*1:HF*1 (11.8%) associated with the AluHJ insertion. This comparative study of multilocus POALINs in the HLA class I region of seven Chinese ethnic populations shows that POALINs alone or together with the HLA class I alleles are informative genetic markers for the identification of HLA class I allele and haplotype lineages and variations such as crossing over events within the same and/or different populations.

Vitamin D receptor genetic polymorphisms and tuberculosis: updated systematic review and meta-analysis

BACKGROUND

Host genetic susceptibility has been suggested as one of the most important explanations for inter-individual differences in tuberculosis (TB) risk. The vitamin D receptor (VDR) gene has been studied as a candidate locus due to genetic polymorphisms that affects the activity of the receptor and subsequent downstream vitamin D-mediated effects.

METHODS

We reviewed published studies on VDR polymorphisms and TB susceptibility up to 15 April 2009 and quantitatively summarised associations of the most widely studied polymorphisms (FokI, TaqI, ApaI and BsmI) using meta-analysis.

RESULTS

A total of 23 eligible studies were included in this review. Heterogeneous results were observed, which may be partly explained by the differences between populations. Among Asians, the FokI ff genotype showed a pronounced positive association (OR 2.0, 95%CI 1.3-3.2), a significant inverse association was observed for the BsmI bb genotype (OR 0.5, 95%CI 0.4-0.8), and marginal significant associations were found for TaqI and ApaI polymorphisms. However, none of the polymorphisms was significantly related to TB among Africans or South Americans.

CONCLUSIONS

The association of VDR polymorphisms with risk of TB observed in our analyses supports the hypothesis that vitamin D deficiency might play a role as risk factor during the development of TB.

Tumor Ki67 Proliferation Index within 4 Weeks of Initiating Neoadjuvant Endocrine Therapy for Early Identification of Non-Responders

Background: The Preoperative Endocrine Prognostic Index (PEPI) scores the independent prognostic effects of tumor pathologic staging and expression levels of ER and the “proliferation” marker Ki67 in the surgical sample to predict long term outcomes after completion of neoadjuvant endocrine treatment (Ellis et al JNCI 100:1380, 2008). A limitation of the PEPI is that the prognostic information becomes available only after 4 months of treatment. We therefore evaluated the value of an early assessment of the Ki67 level in a tumor biopsy sample taken two to four weeks after initiating treatment in two neoadjuvant endocrine therapy trials for the purposes of the early identification of non- respondersMethods: A Ki67 cut point of greater than 10% for poor outcome in ER+ breast cancer was derived by comparing the PAM50 intrinsic subtype profile using a qRT-PCR assay with Ki67 data in a 700+ sample data set. A baseline level of 10% or less correlated most closely with a PAM50-based definition of LumA breast cancer and above 10% LumB breast cancer. We subsequently applied the 10% cut point to the baseline and early on-treatment Ki67 data in two trials, POL (Olson et al JACS 208:906, 2009) and IMPACT (Smith et al JCO: 23, 5108, 2005).Results: At baseline the dichotomized Ki67 definition was not significantly predictive for surgical Ki67 level, PEPI score or RFS in this modest size sample set. In contrast, in a result that emphasizes the enhaced prognostic properties of the on-treatment Ki67 approach, the one month POL sample Ki67 values (62 patients) predicted a higher level of Ki67 in the surgical samples at four months after treatment initiation (P=.01), a poorer PEPI score (P=0.01), a smaller number of patients in the PEPI risk point zero group (P=0.08) and worse relapse free survival (P=0.003). The IMPACT data (153 patients) confirmed that a two week Ki67 &gt;10% predicted higher Ki67 in the surgical specimen (P=0.001), a poorer PEPI score (P=0.001), smaller numbers of patients in the PEPI 0 risk point group (P= 0.004) and worse relapse free survival (P=0.008).Ki67 and OutcomePOL 4W Ki67% PEPI 0RFS (events)10%&gt;1/19 (5%)5/21 (23%)10%≤10/36 (28%)1/41 (2.4%)P ValueP=0.08 (Fisher)P=0.003 (log rank)IMPACT 2W Ki67% PEPI 0RFS (events)10%&gt;0/32 (0%)9/35 (26%)10%≤21/101 (21%)13/118 (11%)P ValueP=0.004 (Fisher)P=0.008 (log rank) Conclusions: A tumor Ki67 assessment taken a short time (2 to 4 week window) after the initiation of neoadjuvant AI identifies patients with poor outcome ER+ disease. Amendment 6 of the neoadjuvant endocrine therapy protocol ACOSOG Z1031 will triage patients with an “on treatment” Ki67 value above 10% to chemotherapy in order to assess the pathological response rate to cytotoxic therapy in this important tumor subset.Supported by R01 CA095614, Avon PFP award 3P50 CA68438-07S2, U01 CA114722, ACOSOG U10 CA 76001, Breakthrough Cancer UK and AstraZenica (IMPACT trial).

Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 78.

Flexible CO2 laser system for fundamental research related to an extreme ultraviolet lithography source

A CO(2) laser system with flexible parameters was developed for fundamental research related to an extreme ultraviolet (EUV) lithography source. The laser is a master oscillator and power amplifier (MOPA) system, consisting of a master oscillator, an externally triggered plasma switch, a preamplifier, a main amplifier, and electronic synchronization units. The laser pulse duration can be varied easily from 10 to 110 ns, with a constant peak power for pulse durations from 25 to 110 ns. The MOPA laser system can also be operated in dual-oscillator mode to produce laser pulse with pulse duration as long as 200 ns and a train of laser pulses with flexible interval. The divergence of the laser beam is 1.3 times the diffraction limit. The laser intensity on the target surface can be up to 8x10(10) W/cm(2). Utilizing this CO(2) MOPA laser system, high conversion efficiency from laser to in-band (2% bandwidth) 13.5 nm EUV emission has been demonstrated over a wide range of laser pulse durations.

Osteoporosis in china

SUMMARY

Based on related studies published between 1980 and May 2008, we examine the prevalence of osteoporoses in mainland China, Hong Kong, and Taiwan. Overall, the prevalence of osteoporosis among these Chinese populations remains low compared to other Caucasian populations; in the mainland, it was approximately 13%.

INTRODUCTION

Osteoporosis is a significant public health problem and has received great attention in industrialized countries. However, limited is known in many developing countries including China, where aging and changing lifestyles likely contribute to increased osteoporosis. The objectives of the study is to examine the disease burden (prevalence) and time trends of osteoporosis in mainland China, Hong Kong, and Taiwan.

METHODS

Related studies published in English and Chinese between January 1980 and May 2008 were reviewed and analyzed.

RESULTS

The prevalence increased with age and varied dramatically based on local versus international diagnosis criteria. In the mainland, reported overall prevalence of osteoporosis based on nationwide surveys ranged from 6.6% to 19.3% (average = 13.0%). The prevalence varied considerably across studies, and by regions, gender, and bone sites, but the urban to rural difference was small. In Hong Kong, the prevalence among women > or =50 years ranged from 34.1-37% in the spine; was 7% in the same aged men. In Taiwan, among those aged > or =50 years, average prevalence of osteoporosis was 11.4% in women and 1.6% in men.

CONCLUSIONS

Future national programs need to monitor the burden of osteoporosis in China though available data indicate that the prevalence of osteoporosis remains low compared to that of other Caucasian populations.

Distribution of HLA-A, -B, -Cw, and -DRB1 alleles and haplotypes in an isolated Han population in Southwest China

In this study, polymorphisms of human leukocyte antigen (HLA) class I (A, B, and Cw) and class II (DRB1) loci were analyzed in an isolated Han population living in Fengyandong in the Yunnan province of Southwest China (FYDH) using a high-resolution polymerase chain reaction-Luminex typing method. A total of 13 A, 26 B, 15 Cw, and 23 DRB1 alleles of HLA were found in FYDH. The frequencies of A*1101, A*0207, A*2402, B*4601, B*1502, Cw*0102, Cw*0801, DRB1*0901, and DRB1*1202 were >10%. The following haplotypes were common with frequencies >5%: three A-B, four Cw-B, two B-DRB1, two A-B-DRB1, three A-B-Cw, two B-Cw-DRB1, and two A-B-Cw-DRB1 phylogenetic tree and multidimensional scaling analysis based on HLA-A, -B, and -DRB1 allele frequencies of 18 Han populations suggested that FYDH was an isolated Han population, but the analytic result also provided a suggestion that FYDH was genetically related to Chinese Southern Han. According to the characteristics of the HLA allele and haplotype distributions and significantly reduced allelic and haplotypic diversity in FYDH, we deduced that genetic drift and/or selection and subsequent geographic isolation had influenced the distribution characteristics of the HLA gene in FYDH. In addition, significantly reduced allelic and haplotypic diversity in FYDH makes it an ideal homogenous population and very useful model for future investigations of issues related to immunogenetic diseases in the Han population.

Knockdown of Abl interactor 1 expression impairs invadopodia formation, tumor angiogenesis, and markedly slows tumor growth of breast cancer cells

Abstract #2054

Background: Abl interactor 1 (Abi1) is a key regulator of actin polymerization/depolymerization. Previous studies have revealed that Abi1 interacts with Wiskott–Aldrich syndrome protein (Wasp) family proteins, and regulates the nucleation promoting activity of Wasp proteins. In addition to Wasp family proteins, Abi1 also binds to a variety of other signaling molecules, including those involved in the signal transductions of small GTP-binding protein Rac and PI3 kinase. The ability to interact with diverse signaling pathways places Abi1 at a central position in the signaling network that regulates cell motility and proliferation. The involvement of Abi1 in the development of abnormal cytoskeletal functions of cancer cells has recently been reported. It remains unclear, however, how Abi1 exerts its effects in tumor cells and whether it contributes to tumor progression in vivo.&#x2028; Material and Methods: The short hairpin RNA (shRNA)-mediated gene silencing was used, in conjunction with murine tumor xenograft models, to examine the effects of Abi1 knockdown on cytoskeleton remodeling, cell migration, invasion, as well as tumor growth and angiogenesis of MDA-MB231 breast cancer cells.&#x2028; Results: We report here a novel function for Abi1 in the regulation of invadopodia formation as well as in the tumor angiogenesis and invasion of breast cancer cells, possibly through the modulation of Src and matrix metalloproteinase 9 (MMP-9) activities. Abi1 co-localizes with invadopodia, the specialized adhesive/invasive structures believed to control the invasion of tumor cells, in MDA-MB231 breast cancer cells. Epigenetic silencing of the Abi1 gene by shRNA in MDA-MB231 cells impaired the formation of invadopodia and decreased the activity of c-Src and MMP-9. The decreased invadopodia formation and MMP-9 activity correlated with a reduction in the ability of these cells to degrade extracellular matrix (ECM). Remarkably, the knockdown of Abi1 expression inhibited tumor invasion and angiogenesis and markedly slowed tumor growth in xenograft mouse models. Taken together, these results indicate that the Abi1 signaling plays a critical role in breast cancer progression and suggest that this pathway may serve as a therapeutic target for the treatment of human breast cancer.

Citation Information: Cancer Res 2009;69(2 Suppl):Abstract nr 2054.

A comparative genomic analysis between human breast cancer and paired tumor lines derived from transplanation of tumor biopsies into NOD/SCID mice

Abstract #41

Background: Successful preclinical studies of experimental anticancer agents require model systems that recapitulate breast cancer biology and genomic abnormalities as accurately as possible. The use of primary human tumor explants engrafted into the humanized mammary fat pad of NOD SCID mice (HIM technique for "human in mouse") is promising in this regard, but the evidence that the genomic profile of the tumor is stable during serial translatation of human tumors into mice and between mouse passages has not beeen clearly demonstrated.&#x2028; Methods: 4th mammary glands of NOD/SCID mice were humanized by removing mouse mammary epithelia and implanting immortalized human breast fibroblasts. Human breast tumor tissues were dissociated into single cell suspensions and injected into the “humanized” mammary fat pads of NOD/SCID mice. Patient tumors were micro-dissected from the surrounding normal tissue by laser capture microdissection and tumor RNA and DNA was isolated. In addition, tumor RNA and DNA was isolated from xenografts at passage 1, 2, and 3. Agilent 4 x 44K whole genome expression array and 244K array-based comparative genomic hybridization (aCGH) was performed on established xenografts (passage 1-3) as well as the original tumor samples. Exon 9 and 20 of PIK3CA and exon 4 to 9 of TP53 were targeted for mutation detection since these genes are commonly mutated in human breast cancer.&#x2028; Results: To date, eight HIM tumor lines have been successfully established and serially passaged. The HIM number and source of tumor are as follows: HIM2 (primary tumor); HIM 3 (primary tumor); HIM 4 (abdominal wall metastasis); HIM 5 (brain metastasis from the patient used to establish HIM 2); HIM6 (primary breast cancer); HIM7 (chest wall metastasis); HIM 8 (chest wall metastasis); HIM9 (chest wall metastasis). Passage 3 HIM tumors serially transplanted in NOD/SCID mice have similar histopathological features to their original human counterparts (HCP). Sequence analyses of the eight HIM lines reveals mutations in the TP53 gene in three tumor lines and a mutation in PIK3CA gene in one tumor line that are also present in the HCP. aCGH analysis, where available, also demonstated that the positions of the major gene amplifications and deletions in HIM lines are also consistent with the HCP. Furthermore, aCGH shows that genomic structure of the grafts are stable with passage. Immunohistochemistry shows that HIM8 and its HCP are positive for HER2. Molecular subtyping by PAM50 gene list indicates that HIM 2 – 8 tumor lines and their HCP are basal type breast cancer. HIM9 tumor line and its HCP are luminal subtypes, although the proliferation signature was activated in the mouse graft.&#x2028; Conclusions: The HIM mouse system faithfully reproduces the genotypic features of the respective HCP's and is therefore a valuable research engine for the preclinical development of biomarkers, imaging techniques and for the assessment of novel therapeutic approaches, particularly for Basal-type breast cancer.

Citation Information: Cancer Res 2009;69(2 Suppl):Abstract nr 41.