Biomedical subjects

Yong Zhu

Publications and source records attributed to Yong Zhu.

At least 19 recordsLinked to original sources

PubMed2004

Localization and variation of TRAIL and its receptors in human placenta during gestation.

The localization of TRAIL and its receptors in human placenta was studied under light microscopy using immunohistochemistry method. The variation of TRAIL and its receptors with development was also detected by in situ semi-quantification. The syncytiotrophoblast, cytotrophoblast, stromal cells and the capillary endothelium cells in human placenta all appeared to be TRAIL immunoreactive and the immunoreactive material was distributed on membrane and in cytoplasm with negative nuclei. During whole gestation there was no obvious variation of the staining of TRAIL. Although DR4, DR5, DcR1 and DcR2 can also be detected in the placenta throughout pregnancy, DR4 and DR5 staining increased with development whereas DcR1 and DcR2 staining decreased. Interestingly, at the beginning of the gestation DR4 and DR5 staining distributed on the cytotrophoblast mainly, whereas DcR1 and DcR2 mainly located in the syncytiotrophoblast cells. Collectively, these results suggest that human placenta may not only produce TRAIL but also be a TRAIL target organ, and that TRAIL/TRAILR system could take part in the self-homeostasis of placenta during whole gestation.

Animals↗

PubMed2003

9.1C3 is identical to LAIR-1, which is expressed on hematopoietic progenitors.

The leukocyte-associated Ig-like receptor-1 (LAIR-1) is a negative regulator of natural killer (NK) cells, its encoding gene belonging to the leukocyte receptor complex (LRC). Antibody to LAIR-1 can inhibit Ab-induced redirected lysis and TNF-alpha release of effector cells. LAIR-1 contains 2 immunoreceptor tyrosine-based inhibitory motifs (ITIM) in its cytoplasmic region that have been shown to bind constitutively and presumably regulate the tyrosine phosphatase SHP-1 in hematopoietic cells. SHP-1 mutation in mice results in abnormal lymphoproliferation, suggesting that LAIR-1 may also be implicated in regulating hematopoiesis. Here we investigated a monoclonal antibody, 9.1C3, against a NK cell antigen previously described as inducing increased colony formation in in vitro assays of human bone marrow cells. We found that 9.1C3 was expressed on CD34 positive hematopoietic progenitors for the first time. In functional assays, 9.1C3 MAb was able to inhibit Ab-induced redirected lysis and TNF-alpha secretion of NK cells. We proved that 9.1C3 is identical to LAIR-1, based on the fact that not only the antigen precipitated by 9.1C3 MAb was of 40kDa but also 9.1C3 MAb bound specifically to LAIR-1 cDNA transfected COS7 cells as well as recognized LAIR-1 fusion protein in ELISA. This finding provided the first evidence that LAIR-1 expresses on hematopoietic progenitor, implicating its role in the regulation of hematopoiesis at early stage.

Animals↗

PubMed2003

Telomere dysfunction: a potential cancer predisposition factor.

BACKGROUND: Genetic instability associated with telomere dysfunction (i.e., short telomeres) is an early event in tumorigenesis. We investigated the association between telomere length and cancer risk in four ongoing case-control studies. METHODS: All studies had equal numbers of case patients and matched control subjects (92 for head and neck cancer, 135 for bladder cancer, 54 for lung cancer, and 32 for renal cell carcinoma). Telomere length was measured in peripheral blood lymphocytes from study participants. Genetic instability was assessed with the comet assay. Patient and disease characteristics were collected and analyzed for associations with risk for these cancers. All statistical tests were two-sided. RESULTS: Telomeres were statistically significantly shorter in patients with head and neck cancer (6.5 kilobases [kb]) than in control subjects (7.4 kb) (difference = 0.9 kb, 95% confidence interval [CI] = 0.5 to 1.2 kb; P<.001). Nine percent of patients with head and neck cancer were in the longest quartile of telomere length, whereas 59% were in the shortest quartile. Similar patterns were observed for lung, renal cell, and bladder cancer. When subjects were categorized into telomere length quartiles defined by the distribution in control subjects, the following inverse relationship between telomere length and cancer risk was observed: adjusted odds ratios [ORs] for decreasing quartiles = 0.84 (95% CI = 0.36 to 1.97), 1.77 (95% CI = 0.72 to 4.36), and 5.11 (95% CI = 1.90 to 13.77). In stratified analysis, we found a suggestive greater-than-additive interaction between smoking status and telomere length: for ever smokers with short telomeres, OR = 25.05 (95% CI = 6.91 to 90.73); for never smokers with short telomeres, OR = 6.18 (95% CI = 1.72 to 22.13); and for ever smokers with long telomeres, OR = 6.49 (95% CI = 1.54 to 27.38). Telomere length was statistically significantly and inversely associated with baseline and mutagen-induced genetic instability. CONCLUSION: Short telomeres appear to be associated with increased risks for human bladder, head and neck, lung, and renal cell cancers.

Adult↗

PubMed2003

From genotype to phenotype: correlating XRCC1 polymorphisms with mutagen sensitivity.

This study correlated the extent of induced in vitro chromosomal damage, assessed by the mutagen sensitivity assay, with genotypes of the X-ray repair cross complementing group 1 (XRCC1) gene, which encodes for a base excision repair protein. There are two common polymorphisms that cause amino acid substitutions in XRCC1, one at codon 194 in exon 6 and another at codon 399 in exon 10. We genotyped these two polymorphisms in 524 healthy subjects and performed mutagen sensitivity assays using both bleomycin and benzo[a]pyrene-diol-epoxide (BPDE) as challenge mutagens. Our results showed that individuals with the wildtype exon 6 Arg/Arg exhibited significantly higher values of chromosomal breaks per cell (b/c) than those with one or two variant Trp alleles (P=0.005 for bleomycin and P=0.05 for BPDE). For the exon 10 polymorphism, subjects who were Gln/Gln homozygotes had higher b/c than did those with other genotypes, with evidence of a gene dosage effect. When we combined the two polymorphic sites and used the exon 6 Arg/Trp and Trp/Trp and exon 10 Arg/Arg genotypes as the reference category, these differences were enhanced for bleomycin sensitivity (P for trend = 0.032), but not for BPDE sensitivity (P for trend = 0.821). These data are biologically plausible since codon 399 is located within the BRCA1 C-terminus functional domain and codon 194 is in the linker region of the XRCC1 N-terminal functional domain. To our knowledge, this is the largest study conducted evaluating the functional relevance of these polymorphisms.

7,8-Dihydro-7,8-dihydroxybenzo(a)pyrene 9,10-oxide↗

PubMed2003

Sequence and structural diversity in endotoxin-binding dodecapeptides.

For the study of sequence or structure requirement of short peptides for endotoxin binding, and to search for potential endotoxin antagonists, biopanning was carried out on a phage-displayed random dodecapeptide library against immobilized lipopolysaccharide (LPS) or lipid A (LA), the core toxic portion of LPS. Specific binding of selected phage-displayed peptides to LPS/LA was confirmed by surface plasmon resonance (SPR) analysis. These peptides are rich in basic and hydrophobic amino acids, especially histidine, proline and tryptophan, highlighting apparent amphiphilicity and bacterial membrane activity. These dodecapeptide sequences have no predictable secondary structure in solution, indicating the importance of a random structure before their interaction with LPS/LA. Sequence alignment reveals various potential secondary structures with these selected peptides, which contain specific signature motifs such as b(p)hb(p)hb(p), bbbb, hhhh (b-basic, p-polar, h-hydrophobic residue), capable of binding LPS/LA. However, none of these peptides exhibit a significant calculated structural amphiphilicity while assuming a secondary structure. This study suggests that for these short dodecapeptides to bind LPS/LA, the potential for their structural adaptation is more important than an amphipathic structure.

Amino Acid Sequence↗

PubMed2003

Death receptor 4 and bladder cancer risk.

Tumor necrosis factor-related apoptosis-inducing ligand stimulates the extrinsic apoptoticpathway by binding to death receptors 4 (DR4) and 5 (DR5). In DR4 exon 4, a C-->G polymorphism at amino acid 626 located immediately 3' to one of the main receptor ligand interface regions, results in a threonine-->arginine change. We found that the DR4 exon 4 G/G genotype was associated with an overall decreased risk of bladder cancer in Caucasians [odds ratio (OR) = 0.58; 95% confidence interval (CI), 0.38-0.88]. This protective effect was more apparent in younger individuals (OR = 0.42; 95% CI, 0.20-0.87) than in older individuals (OR = 0.60; 95% CI, 0.35-1.02) and in women (OR = 0.45; 95% CI, 0.20-0.99) than in men (OR = 0.60; 95% CI, 0.36-0.99). Moreover, the protective effect was greater for light smokers (OR = 0.19; 95% CI, 0.06-0.59) compared with heavy smokers (OR = 0.83; 95% CI, 0.41-1.69). These data provide the first large-scale molecular epidemiological evidence that the DR4 polymorphism is associated with environmental exposure and bladder cancer risk, possibly through modulating the capacity of the receptor ligand complex to engage the apoptotic pathway.

Alleles↗

PubMed2003

Identification, classification, and partial characterization of genes in humans and other vertebrates homologous to a fish membrane progestin receptor.

Recently we discovered a previously uncharacterized gene with the characteristics of a membrane progestin receptor (mPR) in a fish model, spotted seatrout. Here, we report the identification, cloning, and characteristics of other members of this hitherto unknown family of putative mPRs from several vertebrate species, including human, mouse, pig, Xenopus, zebrafish, and Fugu, with highly conserved nucleotide and deduced amino acid sequences and similar structures to the spotted seatrout mPR. The 13 vertebrate genes identified seem to belong to an unknown gene family. Phylogenetic analysis indicates these cDNAs comprise three distinct groups (named alpha, beta, and gamma) within this gene family. Structural analyses of the translated cDNAs suggest they encode membrane proteins with seven transmembrane domains. The transcript sizes of the human alpha, beta, and gamma putative mPR mRNAs varied from 2.8 to 5.8 kb and showed distinct distributions in reproductive, neural, kidney and intestinal tissues, respectively. Recombinant human alpha, gamma, and mouse beta proteins produced in an Escherichia coli expression system demonstrated high affinity (K(d) = 20-30 nM) saturable binding for progesterone. Further analysis of binding to the gamma-subtype revealed binding was specific for progestins and was displaceable, with rapid rates of association and dissociation (t(1/2) = 2-8 min). These results suggest this is a new family of steroid receptors unrelated to nuclear steroid receptors, but instead having characteristics of G protein-coupled receptors.

Amino Acids↗

PubMed2003

Cloning, expression, and characterization of a membrane progestin receptor and evidence it is an intermediary in meiotic maturation of fish oocytes.

The structures of membrane receptors mediating rapid, nongenomic actions of steroids have not been identified. We describe the cloning of a cDNA from spotted seatrout ovaries encoding a protein that satisfies the following seven criteria for its designation as a steroid membrane receptor: plausible structure, tissue specificity, cellular distribution, steroid binding, signal transduction, hormonal regulation, and biological relevance. For plausible structure, computer modeling predicts that the protein has seven transmembrane domains, typical of G protein-coupled receptors. The mRNA (4.0 kb) is only detected in the brain and reproductive tissues on Northern blots. Antisera only detect the protein (40 kDa) in plasma membranes of reproductive tissues. The recombinant protein produced in an Escherichia coli expression system has a high affinity (K(d) = 30 nM), saturable, displaceable, single binding site specific for progestins. Progestins alter signal transduction pathways, activating mitogen-activated protein kinase and inhibiting adenylyl cyclase, in a transfected mammalian cell line. Inhibition of adenylyl cyclase is pertussis toxin sensitive, suggesting the receptor may be coupled to an inhibitory G protein. Progestins and gonadotropin up-regulate both mRNA and protein levels in seatrout ovaries. Changes in receptor abundance in response to hormones and at various stages of oocyte development, its probable coupling to an inhibitory G protein and inhibition of progestin induction of oocyte maturation upon microinjection of antisense oligonucleotides are consistent with the identity of the receptor as an intermediary in oocyte maturation. These characteristics suggest the fish protein is a membrane progestin receptor mediating a "nonclassical" action of progestins to induce oocyte maturation in fish.

Animals↗

PubMed2003

Preparation and characterization of a set of monoclonal antibodies to TRAIL and TRAIL receptors DR4, DR5, DcR1, and DcR2.

The tumor necrosis factor-related apoptosis-inducing ligand (TRAIL/Apo 2L) is a novel cytotoxic ligand belonging to TNF superfamily. Among TRAIL receptors, death receptor 4 (DR4) and DR5 containing death domain (DD) in their cytoplasmic region mediate apoptosis-signaling upon TRAIL binding, while decoy receptor 1 (DcR1) and DcR2 with a truncated or non-functional DD play "decoy" role. The interaction of TRAIL and TRAIL receptors plays important roles both in immunoregulation and immune pathogenesis of some diseases. In this study, we raised hybridomas secreting monoclonal antibodies against TRAIL (FMU1.1, 1.2, 1.3), DR4 (FMU1.4), DR5 (FMU1.5, 1.6), DcR1 (FMU1.7) and DcR2 (FMU1.8, 1.9). These MAbs could be used for fluorescent staining and flow cytometry (FCM) analysis as well as immunohistochemistry (IHC). Moreover, FMU1.1, 1.3, 1.4 and 1.5 could be used as coating antibodies paring corresponding polyclonal antibodies to develop sandwich ELISAs to quantitate the soluble TRAIL (sTRAIL), sDR4 or sDR5 in serum samples respectively. In addition, cross-linking of DR4/DR5 by FMU1.4 or FMU1.5 MAbs could induce apoptosis of some DR4/DR5-expressing tumor cells. Thus, this set of monoclonal antibodies against TRAIL or TRAIL receptors may be useful in expression phenotypic and functional study of TRAIL and TRAIL receptors.

Animals↗

PubMed2003

Tandem repeats of Sushi3 peptide with enhanced LPS-binding and -neutralizing activities.

Endotoxin, also known as lipopolysaccharide (LPS), is the major mediator of septic shock due to Gram-negative bacterial infection. Chemically synthesized S3 peptide, derived from Sushi3 domain of Factor C, which is the endotoxin-sensitive serine protease of the limulus coagulation cascade, was previously shown to bind and neutralize LPS activity. For large-scale production of this peptide and to mimick other pathogen-recognizing molecules, tandem multimers of the S3 gene were constructed and expressed in Escherichia coli. The recombinant tetramer of S3 (rS3-4mer) was purified by anion exchange and digested into monomers (rS3-1mer). Both the rS3-4mer and rS3-1mer were functionally analyzed for their ability to bind LPS by an ELISA-based method and surface plasmon resonance. The LAL inhibition and TNFalpha-release test showed that rS3-1 mer can neutralize the LPS activity as effectively as the synthetic S3 peptide, while rS3-4mer displays an enhanced inhibitory effect on LPS-induced activities. Both recombinant peptides exhibited low cytotoxicity and no haemolytic activity on human cells. This evidence suggests that the recombinant sushi peptides have potential use for the detection, removal of endotoxin and/or anti-endotoxin strategies.

Arthropod Proteins↗

PubMed2003

Stimulation of BMP-2 expression by pro-inflammatory cytokines IL-1 and TNF-alpha in normal and osteoarthritic chondrocytes.

BACKGROUND: Destruction of cartilage in osteoarthritis is a direct effect of an imbalance between catabolic and anabolic activities in the tissue. While a great deal is known about catabolism, we sought to determine the biochemical basis of the anabolic activity. METHODS: Cartilage was isolated from normal and osteoarthritic patients and subjected to both cell and explant culture. mRNA expression levels of the growth and differentiation factors bone morphogenetic protein-2 (BMP-2), BMP-4, BMP-6, cartilage-derived morphogenetic protein-1 (CDMP-1), connective tissue growth factor (CTGF), and activin were determined. BMP-2 was localized in osteoarthritic cartilage by immunohistochemistry. To determine the mechanism of BMP-2 stimulation, chondrocytes were cultured with TGF-beta (transforming growth factor-beta), insulin-like growth factor-1 (IGF-1), interleukin-1beta (IL-1beta), and tumor necrosis factor-alpha (TNF-alpha). The BMP-2 response was monitored by quantitative real-time polymerase chain reaction to ascertain mRNA levels and by Western blot analysis, BMP-2 protein quantitation, and immunohistochemistry to determine protein levels. RESULTS: BMP-2 was found to be up-regulated in osteoarthritic chondrocytes and cartilage. In cell culture, IL-1beta and TNF-alpha increased BMP-2 mRNA and protein levels by eightfold and fifteenfold, respectively, whereas IGF-1 and TGF-beta1 had no effect. In cartilage explant cultures, IL-1beta and TNF-alpha increased BMP-2 levels both intracellularly and extracellularly. Functional relevance was suggested by co-localization of BMP-2 and newly synthesized type-II procollagen within the same cells. CONCLUSIONS: BMP-2 acts as a stimulus of anabolic activities in normal and osteoarthritic chondrocytes. Furthermore, the pro-inflammatory cytokines IL-1beta and TNF-alpha, known to be present in synovium and cartilage of patients with osteoarthritis, stimulate the production of active BMP-2.

Aged↗

PubMed2003

Time-dependent inhibitory effects of indomethacin on spinal fusion.

BACKGROUND: The use of nonsteroidal anti-inflammatory drugs following spine arthrodesis is discouraged because of the negative effects on bone-healing. We are not aware of any data regarding when nonsteroidal anti-inflammatory drugs may be safely resumed postoperatively. We hypothesized that these drugs have a time-dependent deleterious effect on fusion, with the greatest inhibition during the early phases of fusion. METHODS: Seventy New Zealand White rabbits underwent posterior intertransverse process arthrodesis at L5-L6 with use of iliac autograft. Rabbits randomly received indomethacin (10 mg/kg orally) starting at two weeks after surgery (twenty-four animals), indomethacin starting at four weeks postoperatively (twenty-three), or saline starting at two weeks postoperatively (twenty-three) (the control group). The animals were killed at six weeks, and the spines were denuded of soft tissues and palpated for L5-L6 motion. Fusion was defined as the complete absence of motion. RESULTS: Sixty-five percent (fifteen) of the twenty-three spines in the control group and 48% (eleven) of the twenty-three in the four-week group fused. However, only 21% (five) of the twenty-four spines in the two-week group fused. The difference between the two-week and control groups was significant (p < 0.002), as was the difference between the two and four-week groups (p = 0.05). The difference between the four-week and control groups was not significant (p = 0.2). CONCLUSIONS: The earlier that indomethacin was resumed postoperatively, the greater was its negative effect on fusion. Indomethacin appears to play a significant inhibitory role in the early phase of healing. Initiating indomethacin treatment in the latter phase of healing does not appear to significantly affect fusion rates, although there was a nonsignificant trend toward inhibition. To our knowledge, this is the first investigation of the time-dependent nature of indomethacin's effect on bone-healing.

Animals↗

PubMed2003

[Screening for lifespan-extension mutants with paraquat in Arabidopsis].

Genetic analyses of lifespan in model animals have revealed that extended lifespans are closely associated to increased resistance to oxidative stress. In the model plant Arabidopsis, late-flowering mutants are also found to be more tolerant to oxidative stress. However, Arabidopsis mutants with extended lifespans are poorly studied so far. In this study, a screening system for mutants with extended lifespans in Arabidopsis was established using paraquat, a potent herbicide that exacerbates O2-. radical production. The relationship between lifespan and resistance to oxidative stress was examined with one of the mutants, SFNA-9-4. Compared to that of wild type, the lifespan of SFNA-9-4 is significantly extended, and its resistance to oxidative stress is also significantly elevated. These results suggest that, as in Drosophila, paraquat can also be used to screen for mutants with extended lifespans in Arabidopsis.

Animals↗

PubMed2002

A case-control analysis of lymphocytic chromosome 9 aberrations in lung cancer.

Cytogenetic aberrations on chromosome 9 have been reported to be one of the most frequent genetic changes in lung tumorigenesis. Although many of these changes have been detected in lung carcinoma specimens, there is growing evidence showing the concordance between chromosomal alterations in primary lung tumors and peripheral blood lymphocytes (PBLs). We investigated whether spontaneous aberrations on chromosome 9 in PBLs are associated with the presence of lung cancer and with a family history of cancer. A personal interview, to construct a detailed epidemiologic profile including family history of cancer, was conducted on 174 lung cancer cases and 162 matched controls. One hundred metaphases from PBLs of each subject were analyzed for chromosome 9 aberrations using the whole chromosome painting technique. Overall, the mean proportion of individuals with chromosome 9 abnormalities in their PBLs was significantly higher in cases (96.0%) than in controls (60.5%) (p < 0.05). After adjustment by age, gender, ethnicity, family size, and pack-years, there was a 16.63-fold significantly elevated odds ratio (OR) for lung cancer associated with chromosome 9 aberrations. When subjects were categorized by frequencies of the chromosome 9 lesions, we observed significantly increased odds ratios of 11.13 (4.66, 26.58) and 27.45 (11.15, 67.54) for individuals with 1 chromosome 9 aberration and >/=2 chromosome 9 aberrations, respectively. By performing family history analyses, we further observed that control individuals with chromosome 9 aberrations were more likely to report a family history of any cancer (OR = 1.67 [0.84, 3.32]) and lung cancer (OR = 2.49 [0.81, 7.67]). Our findings suggest that chromosome 9 aberrations in PBLs might be considered a marker of lung cancer predisposition and may be associated with familial aggregation of cancer.

Case-Control Studies↗

PubMed2002

BPDE-induced lymphocytic 3p21.3 aberrations may predict head and neck carcinoma risk.

BACKGROUND: Tobacco exposure is an established risk factor for head and neck squamous cell carcinoma (HNSCC). Benzo[alpha]pyrene diol expoxide (BPDE), a main metabolic product of the tobacco smoke constituent benzo[alpha]pyrene, induces chromosomal aberrations at specific loci. Chromosomal aberrations in peripheral blood lymphocytes (PBLs) induced by BPDE may reflect individuals' genetic susceptibility to tobacco carcinogens. METHODS: This study was designed to detect BPDE-induced aberrations in PBLs at locus 3p21.3 in cultured lymphocytic cells. Our hypothesis is that the presence of BPDE-induced 3p21.3 aberrations is a biomarker of an individual's genetic susceptibility and that individuals with these aberrations are at an increased risk for HNSCC. PBL cultures from 52 cases and 54 controls were treated with 2 microM BPDE for 24 hours before the 3p21.3 aberrations were assessed by fluorescence in situ hybridization. One thousand lymphocyte interphases were scored for each sample. RESULTS: We found that BPDE-induced chromosome 3p21.3 aberrations occurred more frequently in cases (mean: 31.4 per 1000 cells) than in controls (mean: 22.1 per 1000 cells; P < 0.001). However, when 6q27 was selected as a control locus, no such difference was observed (P = 0.545). When the 75th percentile value of induced aberrations in the controls was used as a cutoff point to classify 3p21.3 BPDE-induced sensitivity, 30 of the 52 cases (57.69%) and only 14 of the 54 controls (25.93%) were sensitive to BPDE exposure. This approach resulted in an odds ratio of 4.8 (95% confidence interval: 1.87-12.28) for HNSCC risk associated with BPDE-induced 3p21.3 aberrations. There was also a dose-response relationship between the number of BPDE-induced aberrations at 3p21.3 and risk for HNSCC. CONCLUSIONS: The results from this study demonstrated that 3p21.3 may be a specific molecular target of tobacco carcinogens and that BPDE sensitivity at this locus may reflect an individual's genetic susceptibility to HNSCC.

7,8-Dihydro-7,8-dihydroxybenzo(a)pyrene 9,10-oxide↗

PubMed2002

Genetic instability of specific chromosomes associated with a family history of cancer.

This study evaluated the association between family history of cancer and bleomycin-induced mutagen breaks at specific chromosomes. The authors' hypothesis was that individuals exhibiting mutagen-induced specific chromatid breaks might have genetic instability and thus be more likely to report a family history of cancer. The study included 78 healthy individuals. All subjects completed a personal interview to collect epidemiologic information, including a detailed family history of cancer, and donated a 10-mL blood sample. Bleomycin-induced mutagen sensitivity on specific chromosomes was quantified by counting the bleomycin-induced specific chromosomal breaks with Q-banding techniques. We found that chromosome 4 breaks were significantly associated with a positive family history of cancer in first-degree relatives with an odds ratio of 3.18 and 95% confidence interval of 1.05-9.61. However, none of the other chromosomes showed significantly increased risk with family cancer history. In addition, the mutagen-induced chromosome 4 breaks were not associated with age, sex, ethnicity, or smoking status. These findings suggested that chromosome 4 mutagen sensitivity might be a predictor of familial susceptibility to cancer.

Aged↗

PubMed2002

Extracellular domain of TGFbeta type III receptor inhibits angiogenesis and tumor growth in human cancer cells.

TGFbeta overexpression in human cancer cells has been shown to promote tumor progression. In the present study, we sought to determine whether sequestration of endogenous TGFbeta by the expression of a soluble TGFbeta type III receptor (sRIII), can reduce malignancy in human carcinoma cells and whether the tumor-suppressive activity of sRIII is associated with the inhibition of angiogenesis. Ectopic expression of sRIII significantly inhibited the growth of tumors formed by human colon carcinoma HCT116 and breast carcinoma MDA-MB-435 cells in nude mice. It also reduced the metastatic potential of the MDA-MB-435 cells. Thus, endogenous TGFbeta appears to be necessary for the progression of these two carcinomas. Furthermore, when the tumor cells were mixed with Matrigel and embedded subcutaneously in nude mice, the blood volume in Matrigel plugs containing sRIII-expressing cells as indicated by hemoglobin levels was significantly lower than that in Matrigel plugs containing the respective control cells. Blood vessel counts in paraffin sections of the Matrigel plugs containing sRIII-expressing cells were also significantly lower than those in paraffin sections of the Matrigel plugs containing control cells. Treatment of human endothelial cells with a recombinant sRIII significantly inhibited their ability to form a capillary web structure on Matrigel. These results for the first time indicate that the sRIII-induced tumor suppression appears to be in part due to the inhibition of angiogenesis.

Angiogenesis Inhibitors↗

PubMed2002

Chromosome instability in lymphocytes: a potential indicator of predisposition to oral premalignant lesions.

Oral premalignant lesions (OPLs) are related to tobacco use and mark individuals at high risk for oral cancer development. Increased mutagen sensitivity as measured by an in vitro mutagen challenge assay has been shown to be a risk factor for upper aerodigestive tract cancers. In this case control study, we used two assays with mutagens relevant to tobacco exposure (benzo[a]pyrene diol epoxide (BPDE) and bleomycin) to see whether sensitivity to these mutagens could be used as biomarkers for assessing risk of premalignant lesions. Furthermore, we evaluated whether 3p21.3 is a molecular target of BPDE damage in lymphocytes of patients with OPLs. There were 82 patients with OPLs and 89 healthy controls frequency matched to the cases on age, sex, ethnicity, and smoking status. These subjects' lymphocytes were treated in two separate experiments with either 2 microM BPDE for 24 h or 0.03 units/ml bleomycin for 5 h, and the frequency of induced chromatid breakage in Giemsa-stained preparations was determined. BPDE-induced 3p21.3 aberrations were scored by fluorescent in situ hybridization technique in 1000 interphases/sample. We found that the mean BPDE-induced chromatid breaks per cell were higher in cases than controls (1.05 +/- 0.40 and 0.55 +/- 0.27, respectively; P < 0.01). Similar results were evident with bleomycin-induced chromatid breaks per cell (0.78 +/- 0.37 and 0.57 +/- 0.31, respectively; P < 0.01). After adjusting for age, sex, ethnicity, and smoking status, significantly elevated odds ratios (95% confidence interval) for OPL risk were noted for BPDE sensitivity [12.96 (5.51, 30.46)] and bleomycin sensitivity [3.33 (1.64, 6.77)]. When subjects were categorized into quartiles of the number of breaks per cell, a dose response was observed for both assays. The adjusted odds ratios for subjects with increasing numbers of breaks per cell in quartiles were 2.34, 9.14, and 54.04 for BPDE sensitivity and 1.92, 3.33, and 7.15 for bleomycin sensitivity, respectively. Subjects sensitive to both mutagens had a 50-fold increased risk for OPLs. In addition, there were significantly more BPDE-induced chromosome aberrations at the 3p21.3 locus in cases (51.13/1000) than in controls (40.93/1000; P < 0.0001). However, no such difference was observed for 3q13, a control locus. BPDE-induced 3p21.3 aberrations were associated with an elevated risk for OPLs of 6.08 (2.57, 14.4). The degree of BPDE sensitivity at 3p21.3 and risk for OPLs increased in a dose-dependent manner. In summary, BDPE sensitivity and bleomycin sensitivity appear to be individually and jointly associated with elevated risk of OPLs. Furthermore, 3p21.3 may be a molecular target of BPDE in OPLs. This is the first study to examine mutagen sensitivity in a premalignant condition. The next step is to correlate these findings in surrogate (lymphocyte) tissue with molecular events in the target tissue.

7,8-Dihydro-7,8-dihydroxybenzo(a)pyrene 9,10-oxide↗