Obesity, insulin resistance and oxidative stress: implication for breast carcinogenesis

Abstract #6025

Background: Obesity is associated with a modest increase in the risk of postmenopausal breast cancer (RR = 1.5 – 2.0); but, because nearly a third of the U.S. population is obese, the population attributable risk is estimated at 15%. Obesity can cause insulin resistance culminating in Type II diabetes. Notably, breast cancer incidence is significantly increased in the years preceding a diagnosis of type II diabetes. Because IGFBP-1 expression is tightly regulated by insulin, it is an excellent marker of insulin resistance in healthy individuals.
 Methods: These data are based on well-annotated prospectively acquired baseline blood and breast tissue samples from 72 high risk women between the ages of 37 and 86 years who participated in a chemoprevention trial. None of the women had been diagnosed with Type II diabetes. Women with plasma IGFBP1 levels in the lowest tertile (mean 2.1 ng/ml) were classified as insulin-resistant.
 Results: Plasma IGFBP1 was strongly inversely correlated with BMI (R2 = 0.247, P < 0.0001). Insulin-resistant women had marginally higher mean plasma free estradiol levels than women not classified as insulin-resistant (2.13 x 10-12M versus 1.53 x 10-12M, P = 0.072). There was no difference in plasma IGF1, IGF2, or IGFBP3 levels. Illumina whole genome expression microarray data was available for breast tissue from 55 women. Women classified as insulin-resistant showed evidence of an adaptive response to oxidative stress based on significant upregulation of NQO1, GSTK1, CYP4ZP2, and SRXN1 (P < 0.001).
 Conclusions: Marginally increased circulating estradiol may contribute to the increased breast cancer risk observed in insulin-resistant women. However, insulin resistance increases oxidative stress in breast tissue and may promote carcinogenesis through induction of oxidative DNA damage.

Citation Information: Cancer Res 2009;69(2 Suppl):Abstract nr 6025.

Urotensin II is an autocrine/paracrine growth factor for aortic adventitia of rat

Urotensin II (UII) is a potent vasoconstrictive peptide; however, its significance in vascular adventitia has not been clearly elucidated. In this study, rat aortic adventitia showed mRNA expression and immunoreactivity of UII and its receptor (UT). Moreover, radioligand-binding assay showed that maximum binding capacity (Bmax) of [(125)I]-UII was higher in adventitia than in media (28.60+/-1.94 vs. 20.21+/-1.11 fmol/mg, P<0.01), with no difference in binding affinity (dissociation constant [Kd] 4.27+/-0.49 vs. 4.60+/-0.40 nM, P>0.05). Furthermore, in cultured adventitial fibroblasts, UII stimulated DNA synthesis, collagen synthesis and secretion in a concentration-dependent manner. These effects were inhibited by the UII receptor antagonist urantide (10(-6) mol/l), Ca(2+) channel blocker nicardipine (10(-5) mol/l), protein kinase C inhibitor H7 (10(-6) mol/l), and mitogen-activated protein kinase inhibitor PD98059 (10(-6) mol/l) but not the phosphatidyl inositol-3 kinase inhibitor wortmannin (10(-7) mol/l). UII may act as an autocrine/paracrine factor through its receptor and the Ca(2+) channel, protein kinase C, and mitogen-activated protein kinase signal transduction pathways, in the pathogenesis of vascular remodeling by activating vascular adventitia.

Role of hydrogen sulfide in the development of atherosclerotic lesions in apolipoprotein E knockout mice

OBJECTIVE

We explored the effect of hydrogen sulfide (H(2)S) on atherosclerotic progression, particularly on intracellular adhesion molecule-1 (ICAM-1) in apolipoprotein-E knockout (apoE(-/-)) mice and human umbilical vein endothelial cells (HUVECs).

METHODS AND RESULTS

ApoE(-/-) mice were treated with sodium hydrosulfide (NaHS) or DL-propargylglycine (PPG); HUVECs were pretreated with NaHS. Compared with control mice, apoE(-/-) mice showed decreased plasma H(2)S level and aortic H(2)S production but increased plasma ICAM-1 and aortic ICAM-1 protein and mRNA. Compared with apoE(-/-) mice, apoE(-/-)+NaHS mice showed increased plasma H(2)S level, but decreased size of atherosclerotic plaque and plasma and aortic ICAM-1 levels, whereas apoE(-/-)+PPG mice showed decreased plasma H(2)S level but enlarged plaque size and increased plasma and aortic ICAM-1 levels. NaHS suppressed ICAM-1 expression in tumor necrosis factor (TNF)-alpha-treated HUVECs. NaHS inhibited IkappaB degradation and NF-kappaB nuclear translocation in HUVECs treated with TNF-alpha.

CONCLUSIONS

The vascular CSE/H(2)S pathway was disturbed in apoE(-/-) mice. H(2)S exerted an antiatherogenic effect and inhibited ICAM-1 expression in apoE(-/-) mice. H(2)S inhibited ICAM-1 expression in TNF-alpha-induced HUVECs via the NF-kappaB pathway.

Immunoglobulin variable region gene analysis to the autoantibody-secreting B cells from tumors in association with paraneoplastic autoimmune multiorgan syndrome

OBJECTIVES

We have studied the role of lymphoproliferative tumors in the pathogenesis of autoimmune and the origin of the autoantibodies in PNP. Objectives of this study is to understand the characteristics of immunoglobulin genes of the B-cells isolated from the tumor which can produce auto-antibody.

METHODS

Total RNA of the tumor cells was then isolated and the mRNA was reversely transcribed into cDNA. V(H) and V(L) genes were amplified and cloned and their sequences were analyzed.

RESULTS

49 V(H) genes (527 to 577 bp) and 36 V(L) genes (445 to 454 bp) sequences were cloned from five tumors. All of the IgV(L) were mostly homologous to IGKV4-01 germ-line gene. The frequency of IgV(H) germ-line gene usage in a decreasing order was IGHV3-23 > IGHV3-9 > IGHV4-31 > IGHV4-59. There was more nucleotide changes occurred in complementary determining regions (CDR) than those in the framework regions (FR) in the V(H) and V(L) of B cell clones. In both V(H) and V(L), the probability (P) that the number of observed replacement mutations (R) in the CDRs would occur by random chance was low.

CONCLUSIONS

The clones of B-lymphocytes in the tumors carrying possibly functional rearranged immunoglobulin heavy and light chain genes were isolated and there were high incidences of somatic mutations in CDRs and relatively conserved sequences in framework region.

The regulatory effect of endogenous hydrogen sulfide on pulmonary vascular structure and gasotransmitters in rats with high pulmonary blood flow

The study aimed to explore the regulatory effect of endogenous hydrogen sulfide (H(2)S), a novel gasotransmitter, on pulmonary vascular structure and gasotransmitters in rats with high pulmonary blood flow. Thirty-two Sprague-Dawley rats were randomly divided into a sham group, shunt group, sham+PPG (propargylglycine, an inhibitor of cystathionine-gamma-lyase) group and shunt+PPG group. Rats in the shunt and shunt+PPG groups underwent abdominal aorta-inferior vena cava shunting. Rats in the shunt+PPG and sham+PPG groups were intraperitoneally injected with PPG. After 4 weeks of shunting, mean pulmonary artery pressure (MPAP) and pulmonary vascular structural remodeling (PVSR) were evaluated. H(2)S, nitric oxide (NO) and carbon monoxide (CO) contents were measured in lung tissues. Meanwhile, nitric oxide synthase (eNOS), heme oxygenase (HO-1) and proliferative cell nuclear antigen (PCNA) protein expressions and ERK activation were evaluated. After 4 weeks of shunting, rats showed PVSR with increased lung tissue H(2)S and NO content but decreased CO content. After the PPG treatment, MPAP further increased and PVSR was aggravated. Meanwhile, PCNA expression and ERK activation were augmented with decreased lung tissue CO and HO-1 protein production but increased lung tissue NO production and eNOS expression. H(2)S exerted a protective effect on PVSR, and the inhibition of the NO/NOS pathway and the augmentation of the CO/HO pathway might be involved in the mechanisms by which H(2)S regulates PVSR in rats with high pulmonary flow.

Cell-based breast cancer risk stratification based on DNA methylation in fine needle aspiration samples

1508

Background: Tumor suppressor gene (TSG) methylation is identified in nearly all breast cancers, but rarely in histologically normal breast tissue from wonen unaffected with breast cancer. Its occurrence in high risk preneoplasia and in benign breast tissue adjacent to breast cancer suggests that it may represent a high risk field change that could be exploited for cell-based breast cancer risk stratification. Methods: TSG methylation was measured by quantitative methylation-specific real time PCR in 53 breast tumor fine needle aspiration (FNA) biopsies, 84 cellular random periareolar FNAs (RP-FNA) ipsilateral or contralateral to these cancers, 36 cellular RP- FNAs from unaffected women at high risk for breast cancer by the Gail model, and 95 cellular RP-FNAs from unaffected women at lower risk by the Gail model. Results: The breast tumors showed a high frequency of TSG methylation: RASSF1A 80%, HIN-1 65%, Cyclin D2 60%, RAR-β2 53%, and APC 47%. In general, RP-FNA samples from cancer patients and Gail high risk patients showed a greater frequency of methylation than samples from Gail lower risk patients: RASSF1A 43% vs. 21%, P = 0.001, HIN-1 32% vs. 20%, P = 0.05; Cyclin D2 18% vs. 9%, P = 0.10; RAR-β2 21% vs. 18%, P = 0.68; and APC 25% vs. 16%, P = 0.17. Twelve of 215 RP-FNA samples (5%) showed very high levels of methylation (>10% methylation for two or more genes). Only two of these samples were from women classified as lower risk by the Gail model. Methylation frequencies were entirely independent of cell yields but the frequency of RASSF1A methylation increased with increasing Masood scores (P = 0.05). Methylation of RASSF1A in one breast was highly predictive of RASSF1A methylation in the opposite breast (P < 0.0001). Conclusions: TSG methylation appears to be a breast cancer risk-associated field change that can be quantified in RP-FNA samples. RASSF1A methylation occurs frequently in benign breast epithelium, provides reasonable discrimination between high and lower risk breasts (O.R. = 2.0), is related to cytological atypia, and may be an early marker of a methylator phenotype. Quantification of TSG methylation in RP-FNA samples may provide a valuable surrogate endpoint biomarker for Phase II prevention trials.

No significant financial relationships to disclose.

Screening of common mitochondrial mutations in Chinese patients with mitochondrial encephalomyopathies

To investigate the spectrum of common mitochondrial mutations in Northern China during the years of 2000-2005, 552 patients of mitochondrial encephalomyopathies clinically diagnosed as MELAS, MERRF or Leigh's syndrome, 14 cases of LHON and 46 cases of aminoglycoside induced deafness along with their family members, accepted routine point mutation tests at nucleotide positions 3243, 8344, 8993, 11778 or 1555 in mitochondrial genome. PCR-RFLP analysis, site-specific PCR and PCR-sequencing methods were used to identify the mutations. Fifty-seven cases with A3243G mutation, 4 cases with A8344G, 2 cases with T8993C and 1 case with T8993G were identified from the 552 encephalomyopathy patients. In addition, one case with G11778A was found from the 14 cases of LHON, and 5 cases with A1555G from the 46 cases of aminoglycoside ototoxicity patients. Additional screening for T8356G and T3271C merely had limited significance for the diagnosis of MERRF and MELAS. Differential diagnosis among mitochondrial encephalomyopathies was often complicated due to many similar clinical manifestations. For A3243G mutation, the proportion of mutant mtDNA was not related to severity of the disease but to the age of onset.

Downregulation of CCR5 expression on cells by recombinant adenovirus containing antisense CCR5, a possible measure to prevent HIV-1 from entering target cells

Chemokine (C-C motif) receptor 5 (CCR5) is one of the major co-receptors for the macrophage (M)-tropic HIV-1. To prevent HIV-1 from entering into target cells, we inhibited CCR5 expression on target cell surface by recombinant adenovirus containing anti-sense CCR5 cDNA. A fragment of 653 bp cDNA located in the 5' region of CCR5 cDNA was reversely inserted into pAdTrack-CMV. Recombinant adenovirus containing antisense CCR5 cDNA (Ad-antiR5) was obtained by homologous recombination of resultant plasmid with the adenoviral backbone plasmid pAdEasy-2 in E. coli BJ5183 and then packed in AD-293 cells. Rate of positive CCR5 on U937 cell surface measured by flow cytometry was decreased from 89.53% to 1.88% after U937 cells infected with Ad-antiR5 for 24 hours, and this reduction lasted at least for 10 days. After challenged with HIV-1, the U937 cells infected with Ad-antiR5 produced much less p24 antigen in cultured medium than those infected with control recombinant adenovirus and the uninfected cells. The recombinant adenovirus had no effect on chemotactic activity and proliferation of the U937 cells. Therefore, the recombinant adenovirus containing anti-sense CCR5 cDNA can down-regulate CCR5 expression on U937 cells and protect the cells from HIV-1 infection without effects on their chemotaxis activity and proliferation function.

Assessment of tumor suppressor gene methylation for breast cancer risk screening

1004

Background: Tumor suppressor gene (TSG) methylation is frequently detected in benign proliferative breast tissue suggesting that it occurs early in breast carcinogenesis. If it can be screen-detected and is associated with breast cancer risk it could be exploited for breast cancer prevention. Methods: Nipple duct lavage (NDL) samples, obtained from 150 women selected to represent a wide range of breast cancer risk, were evaluated by quantitative methylation-specific real time PCR. High risk breasts were defined as those contralateral to a breast cancer (N = 63) and those of women with a 5-year Gail risk ≥ twice the age- and race-matched general population risk (N = 64). The prevelence of TSG methylation and marked atypia was compared for high risk and lower risk breasts using Chi-square. Data for breasts ipsilateral to a breast cancer are shown for comparison, but not included in the calculations for the high risk category. Results: Samples with adequate cellularity were obtained for 219 breasts (76%). The proportion of healthy breasts with ≥ 1% of the gene copies methylated was 13% for Cyclin D2, 19% for APC, 19% for HIN-1, 16% for RASSF1A, and 9% for RAR-beta. RAR-beta provided the best risk discrimination as 15% of high risk breasts were methylated at a level that exceeded the 95th percentile of the lower risk breasts (0.9% of gene copies methylated, P = 0.05). For the table , methylation fractions for all five genes were summed and the threshold for classifying a breast as positive was set to the 95th percentile of the lower risk breasts (methylation sum = 25.0%). Both methylation and marked atypia provide some discrimination between high and lower risk breasts; the combination, however, provides the best discrimination (24% marker positive for high risk versus 9% for lower risk, P = 0.02). Conclusions: TSG methylation in NDL samples is a marker of breast cancer risk that is complementary to cytology.

[Table: see text]

[Table: see text]

Epitopes in the linker subdomain region of envoplakin recognized by autoantibodies in paraneoplastic pemphigus patients

Sera from paraneoplastic pemphigus (PNP) immunoprecipitate multiple antigens from human epidermal protein extract. In this study, we further characterized the autoantibodies in 12 PNP sera. Immunoblotting using recombinant linker subdomains of envoplakin, periplakin, desmoplakin, and bullous pemphigoid antigen I found that 11 of the 12 sera recognized linker subdomains of envoplakin and periplakin. We then synthesized 12 peptides covering the linker subdomain of envoplakin for ELISA. One of the peptides, peptide no. 8, was recognized by nine out of the 12 sera with a higher affinity. A method of ligand-receptor binding assay was designed and performed using this peptide labeled with fluorescence as the ligand. Peptide no. 8 bound to CD20+ cells in Castleman's tumors from the patients whose sera were positive to this peptide by ELISA. Our data suggest that the linker subdomain of plakin proteins may be one of the major areas recognized by PNP autoantibodies, and epitopes in the linker subdomain of envoplakin recognized by PNP autoantibodies with a high affinity are dispersed in several areas and are variable among PNP patients. We also demonstrate that B-lymphocyte clones specifically reacting to epidermal proteins exist in Castleman's tumors from PNP.

Modulating effect of hydrogen sulfide on gamma-aminobutyric acid B receptor in recurrent febrile seizures in rats

Hydrogen sulfide (H2S) is recognized as a new neuromodulator in regulating various brain functions. Some of our recent studies showed that H2S alleviates the hippocampal damage induced by recurrent febrile seizures (FS). In the present study, we used a rat model of recurrent FS and found that sodium sulfhydrate (NaHS, a donor of H2S) down-regulated the expression of c-fos and increased the expression of gamma-aminobutyric acid B receptor subunits 1 (GABA(B)R1) and 2 (GABA(B)R2). Hydroxylamine (an inhibitor of cystathionine b-synthase) up-regulated the expression of c-fos and down-regulated the expression of GABA(B)R2, but did not change the expression of GABA(B)R1. These results suggest that H2S plays a regulatory role through modulating GABA(B)R function in the pathogenesis of recurrent FS.

Mutations in the cyp51A gene and susceptibility to itraconazole in Aspergillus fumigatus serially isolated from a patient with lung aspergilloma

OBJECTIVES

To monitor changes in itraconazole susceptibility of isolates from a patient undergoing treatment for pulmonary Aspergillus infection and relate these changes to genotypic/phenotypic alterations.

METHODS

Six Aspergillus fumigatus isolates were serially recovered from the patient. Itraconazole MICs were determined by Etest and NCCLS methodology. Growth characteristics and phenotype were monitored. Molecular analysis included random amplified polymorphic DNA (RAPD) assay and sequencing of the cyp51A gene.

RESULTS

The MIC of itraconazole against the first isolate before treatment was 0.25 mg/L; the MIC against the second isolate, recovered after 6 months of itraconazole therapy, was >16 mg/L; and that against the third isolate, obtained 2 months after discontinuation of the therapy, was 0.5 mg/L. The MIC against the last three isolates, acquired after restoration of itraconazole therapy for 4-7 months, was >16 mg/L. The six isolates shared identical band patterns of RAPD assay using four primers and the same sequence in intertranscribed spacers (ITS). Therefore, the six isolates were likely to be the same strain of A. fumigatus, and mutations involving itraconazole resistance possibly occurred in these isolates after prolonged itraconazole therapy. Sequencing of the cyp51A gene in the coding region revealed a mutation of M220I in cytochrome P450 sterol 14-alpha-demethylase in the second resistant isolate and a mutation of G54R in the last three resistant isolates. Expression changes of some pump genes, such as MDR3, may also, in part, be related to the resistance to itraconazole.

CONCLUSIONS

We conclude that resistance of A. fumigatus to itraconazole occurred in a patient treated with the drug, and the resistance may result from mutations in the cyp51A gene-the gene encoding the target enzyme for itraconazole.

Mutations in SCN9A, encoding a sodium channel alpha subunit, in patients with primary erythermalgia

Primary erythermalgia is a rare autosomal dominant disease characterised by intermittent burning pain with redness and heat in the extremities. A previous study established the linkage of primary erythermalgia to a 7.94 cM interval on chromosome 2q, but the causative gene was not identified. We performed linkage analysis in a Chinese family with primary erythermalgia, and screened the mutations in the two candidate genes, SCN9A and GCA, in the family and a sporadic patient. Linkage analysis yielded a maximum lod score of 2.11 for both markers D2S2370 and D2S2330. Based on critical recombination events in two patients in the family, we further limited the genetic region to 5.98 cM between D2S2370 and D2S2345. We then identified two missense mutations in SCN9A in the family (T2573A) and the sporadic patient (T2543C). Our data suggest that mutations in SCN9A cause primary erythermalgia. SCN9A, encoding a voltage-gated sodium channel alpha subunit predominantly expressed in sensory and sympathetic neurones, may play an important role in nociception and vasomotor regulation.

DNA-based prenatal diagnosis in a Chinese family with xeroderma pigmentosum group A

BACKGROUND

Xeroderma pigmentosum (XP) is a group of autosomal recessive diseases characterized by hypersensitivity to ultraviolet rays. Among its eight complementation groups, XP group A (XPA) is the most severe type. The XPAC gene has been identified as the defective gene in XPA patients.

OBJECTIVES

To examine genomic DNA from a Chinese family with XPA, to determine the XPAC mutation and, after genetic counselling, to undertake DNA-based prenatal diagnosis in a subsequent pregnancy.

METHODS

Fetal DNA was extracted from amniotic fluid and used to amplify exon 5 of XPAC containing the potential mutation. Direct sequencing and restriction endonuclease digestion were used for prenatal diagnosis.

RESULTS

We identified a homozygous nonsense XPAC mutation of 631C-->T, which results in an R211X mutation in XPA protein, in the proband. Both her parents are heterozygous. Prenatal diagnosis demonstrated a heterozygous sequence predicting an unaffected child, and a healthy girl was born.

CONCLUSIONS

These data provide the first example of a DNA-based prenatal test for genodermatosis in China.

Castleman's tumours and production of autoantibody in paraneoplastic pemphigus

BACKGROUND

Paraneoplastic pemphigus is an autoimmune mucocutaneous disease associated with Castleman's tumours, which when surgically removed often result in great improvement of mucocutaneous lesions. An IgG autoantibody against epidermal proteins is often used as a diagnostic marker for disease. Our aim was to ascertain the role of Castleman's tumours in production of the autoantibody and pathogenesis of paraneoplastic pemphigus.

METHODS

We enrolled seven patients with paraneoplastic pemphigus associated with Castleman's disease and assessed the effect of removal of tumours on mucocutaneous lesions in six individuals and on autoantibody titre with indirect immunofluorescence in four patients. We cultured tumour cells from one patient and assayed the secreted autoantibody. Finally, we characterised the gene sequence and expression of the variable region of the immunoglobulin heavy chain (IgV(H)) in tumour B cells from all patients by reverse transcription-PCR, DNA sequencing, and in-situ hybridisation.

FINDINGS

Cutaneous lesions disappeared within 6-11 weeks after resection of tumours. Mucosal lesions also improved in this period, but lasted for 5-10 months overall. Autoantibody titre decreased and became undetectable within 5-9 weeks in three of four patients assessed. We identified secreted autoantibody, similar to that identified in patients' serum, in cultured tumour cells. The tumour B-cells of the seven patients shared and expressed two rearrangement patterns of complementarity determining region 3 (CDR3) of IgV(H).

INTERPRETATION

Secreted autoantibody from Castleman's tumours, which reacts against epidermal proteins, could be an essential factor in the pathogenesis of paraneoplastic pemphigus. We noted clonal rearrangement, resulting in similar variable regions of IgV(H), in tumour B cells isolated from all seven patients. However, whether this pattern is associated with autoimmunity remains to be ascertained.

[The regulatory effect of endogenous hydrogen sulfide on hypoxic pulmonary hypertension]

OBJECTIVE

To study the changes of endogenous H2S and the effect of exogenously applied H2S on hypoxic pulmonary hypertension (HPH).

METHODS

Male Wistar rats were randomly divided into control group (n = 6), hypoxia group (n = 7) and hypoxia + NaHS group (n = 6). The rats that received hypoxia were put into a normobaric hypoxic chamber to respire hypoxic gas containing 10% (volume fraction) O2 for 6 hours everyday. NaHS solution was injected to rats of hypoxia + NaHS group at a dosage of 0.78 mg.kg-1 before hypoxic challenge. After 21 days of hypoxia, the mean pulmonary artery pressure (mPAP) was measured. The weight ratio of right ventricle vs left ventricle and septum [RV/(LV + SP)] was measured. The microstructure and ultrastructure changes in pulmonary small arteries were examined using elastin staining and transparent electron microscope respectively. And the activity of H2S generating enzymes in homogenates of the lung tissue and pulmonary artery was measured. The cystathionine gamma--lyase (CSE) mRNA in lung tissue was also measured using quantitative RT-PCR.

RESULTS

Compared with rats in the control group, the mPAP increased 45.6% (P < 0.01) and the RV/(LV + SP) ratio increased 41% (P < 0.01) in rats of hypoxia group respectively. The relative medium thickness (RMT) and relative medium areas (RMA) increased 41% and 49% respectively (P all < 0.01) under optical microscope. The ultrastructure of the pulmonary small arteries also changed significantly. The H2S generating enzyme activity in lung tissue and in pulmonary artery decreased 52% and 54% respectively (P < 0.01). There were obviously negative correlations between the mPAP and H2S generating enzymes ativity. Relative CSE mRNA amount in lung tissue also decreased 53% (P < 0.01) in rats of hypoxia group compared with that of control group. The mPAP, and the RV/(LV + SP) ratio of rats in hypoxia + NaHS group decreased 31.2%, and 24% respectively compard with that of hypoxia group (P < 0.01). The RMT and RMA in rats of hypoxia + NaHS group also decreased 36% and 31% respectively (P < 0.01). In hypoxia + NaHS group, the H2S generating enzymes activity and relative CSE mRNA amount in the lung tissue increased 67.7% and 110% respectively compared with those in hypoxia group (P all < 0.01).

CONCLUSION

Endogenous H2S was involved in the pathogenesis of rat's HPH. Exogenously applied H2s could exert protective effect during HPH.

Effects of cobalt-60 ?-radiation on the synthesis of adrenomedullin and endothelin in rat vascular smooth muscle cells

We studied the effects of cobalt-60 Gamma-radiation on the gene expression and secretion of adrenomedullin (Adm) and endothelin (ET) in cultured rat vascular smooth muscle cells (VSMCs). Rat VSMCs cultured in Dulbecoo's modified Eagle's medium containing 10% FBS were radiated with cobalt-60 Gamma-radiation at doses of 1, 14, and 25 Gy, respectively. Then the mRNA of Adm and ET in VSMCs were detected by the reverse-transcriptative competitive polymerase chain reaction. Adm and ET levels in rat VSMCs were measured by radioimmunoassay. As compared with that of the control, the secretions of Adm in rat VSMCs radiated at doses of 14 and 25 Gy were increased by 270% (P < 0.05) and 233% (P < 0.05), respectively. The mRNA levels of Adm were increased by 82.4% (P < 0.01) and 101% (P <0.01), respectively. Meanwhile, the secretions of ET were decreased by 27.3% (P < 0.01) and 58.0% (P < 0.01) in VSMCs radiated at doses of 14 and 25 Gy, respectively. In parallel, the mRNA levels of ET were decreased by 47.1% (P < 0.01) and 40.2% (P < 0.01), respectively. Radiation at a dose of 1 Gy had no significant effect on Adm and ET at the gene and protein levels. As compared with the control, the Adm/ET ratios in VSMCs increased by 65% (P > 0.05), 409% (P < 0.01), and 693% (P < 0.01), respectively, with radiation at doses of 1,14 and 25 Gy, respectively. The balance of Adm/ET in VSMCs could be changed by cobalt-60 Gamma-radiation, which might play an important role in the use of radiotherapy for restenosis.

[Study on gene mutation in 11 Chinese families with Hailey-Hailey disease]

OBJECTIVE

To screen and identify gene mutations of 11 Chinese patients with Hailey-Hailey disease (HHD).

METHODS

Cases of HHD were diagnosed by history, clinical menifestations and pathology. Then genomic DNA samples of patients were extracted from perpheral blood leukocytes, and polymerase chain reaction(PCR), DNA sequencing were performed.

RESULTS

We found five mutations in ATP2C1 gene including 3 nonsense mutations and 2 splicing mutations. Four of them were novel mutations.

CONCLUSION

Both nonsense mutation and splicing mutation could affect the rusult of transcription, translation, and the functions of protein encoded by ATP2C1 gene, so the mutations reported in this study is the underlying cause of HHD.

[Expression of chemokine-like factor 2 (CKLF2) mRNA in the rat myocardium after myocardial infarction]

OBJECTIVE

To investigate the expression of chemokine-like factor 2 (CKLF2) mRNA in the rat myocardium after myocardial infarction (MI).

METHODS

In a rat model of MI, the myocardium surrounding the infarcted area was used for RNA preparation at different time points. After RT, competitive polymerase chain reaction amplification was performed to assess the expression of rCKLF2 mRNA. SAS Kruskal-Wallis test was used for statistical comparisons.

RESULTS

The gene expression of rCKLF2 at mRNA level was significantly increased in the myocardium surrounding the infarcted area 3 days, 1 week, 2 weeks after infarction.

CONCLUSION

It is possible that CKLF2 contributes to the pathophysiological process and needs to be further investigated.

Cloning and expression of xeroderma pigmentosum complementation group A cDNA and the identification of its recombinant protein

OBJECTIVE

To clone and express xeroderma pigmentosum, complementation group A (XPA) cDNA and to identify its recombinant protein.

METHODS

Coding region of XPA cDNA was amplified from human tonsil cDNA by reverse transcription and nested PCR. The PCR product was cloned into pBluescript vector, confirmed by DNA sequencing, cloned in frame into a prokaryotic expression vector pTrcHis C and expressed in E. coli. TOP10. The recombinant fusion protein was identified by immunoblotting.

RESULTS

The entire coding region of XPA cDNA was cloned and expressed. The fusion XPA protein was identified by anti-XPA monoclonal antibody on western blot.

CONCLUSION

Cloning of human XPA cDNA and successful expression of recombinant XPA protein will be useful for the construction of a viral gene transfer vector for the gene therapy of XPA.

Immunobiology and long-term graft function in a transplant heterotopic renal rat model

BACKGROUND

The Th1-Th2 paradigm proposes clonal expansion of Th2 lymphocytes as the basis of allograft tolerance. The Th2 cells have been found to be present in recipients with long-term allograft survival. However, the presence of Th2 cells and tolerance is not a uniform finding. Previously we have shown that pre-engraftment single dose rapamycin and a 7-d course of cyclosporin induce transplantation tolerance to 120 d. In the present study, we investigated the immunobiology of grafts in a long-term follow-up (>350 d).

METHODS

Kidney allografts (n = 7), isografts (n = 5) and single nephrectomy (n = 3) groups were followed for 350 +/- 87 d. Heterotopic kidney transplant was performed by the same surgeon in the allograft group (ACI-Lewis) and the isograft group (Lewis-Lewis). The left kidney was removed in the single nephrectomy group. The allograft group was treated with pre-engraftment single dose rapamycin and a 7-d course of cyclosporin. A kidney biopsy was performed at midpoint time for histological study and tissue was frozen for measuring intragraft cytokine expression (IL-4, IL-10) in all animals. Prior to biopsy, serum blood urea nitrogen (BUN) and creatinine (Cr) levels were studied. Serum BUN, Cr levels, plus 24-h urinary protein (PRO) were measured prior to sacrifice. Randomly, four allograft rats received skin grafts (ACI, Lewis and Buffalo skin donors) after kidney biopsy. Skin grafts were studied for a mean of 6 weeks for signs of acceptance or rejection. Analysis of variance (ANOVA) with Tukey's test was used; p < 0.05 was considered statistically significant.

RESULTS

The mean follow up was 352 +/- 87 d. BUN and Cr levels at biopsy time (mean 214 d) were not statistically different between the three groups (p = 0.19 and p = 0.66). At sacrifice (mean 352 d), BUN, Cr and PRO were statistically different between allograft and isograft groups (p = 0.013), and between allograft and single nephrectomy groups (p = 0.027). Functional and histological signs of graft loss occurred in three of seven (42.8%) of the allografts at 352 d. Using BANFF criteria, three allografts at biopsy time and seven allografts (100%) and four isografts (80%) at sacrifice time developed chronic histologic changes. Intragraft overexpression of IL-4 and IL-10 was seen at biopsy and sacrifice time in six of seven allografts and one of five isografts. All donor specific skin grafts (ACI-Lewis) on allografts were accepted and third party (Buffalo) donor skin grafts were rejected in all animals (>95% skin necrosis).

CONCLUSIONS

This highly stringent, functional, renal transplant model yields 100% normal renal function as compared with isografts at 120 d follow-up. With the follow-up extended to 350 d, 43% of the allografts loose function and develop a chronic allograft histology despite a demonstrated intragraft Th2 cytokine dominance and donor specific skin graft acceptance.

[The synthesis of MT in rat myocardial fibroblasts]

OBJECTIVE

To study the influence on the synthesis of metallothionein (MT) induced by lipopolysaccharide (LPS), basic fibroblast growth factor (bFGF), oxidized low-density lipoproteins (oxLDL) and ZnCl2 in rat myocardial fibroblasts.

METHODS

The content of MT was measured by 109Cd-Hb saturation method and RT-PCR was used to determine the expression of MT mRNA.

RESULTS

All of the stimulus in this experiment increased the synthesis of MT in myocardial fibroblasts. Compared with control, 1 and 5 mg.L-1 LPS increased the content of MT by 94% and 130% (P < 0.01), 0.2 and 1.0 mg.L-1 bFGF by 41% and 59% (P < 0.01), 2 and 10 mg.L-1 oxLDL by 23% (P < 0.05) and 41% (P < 0.01) respectively. 1,2 and 5 mg.L-1 ZnCl2 increased the content of MT by 66%, 99% and 149% (P < 0.01) in a concentration-dependent manner. 2-8 mg.L-1 ZnCl2 increased the content of MT1 mRNA by 69%-129%, MT2 mRNA by 31%-60% (P < 0.01). But 10 mg.L-1 ZnCl2 didn't stimulate the synthesis of MT more significantly, probably because ZnCl2 of high concentration damaged myocardial fibroblasts and decreased the survival rate of the cells.

CONCLUSION

Many stimulus such as LPS, bFGF, oxLDL and ZnCl2 can induce the synthesis of MT, and ZnCl2 can increase the expression of MT mRNA in rat myocardial fibroblasts.