Biomedical subjects
Publications and source records attributed to Dan Zhao.
A series of Ge132 derivatives have shown enhanced antitumor activity. Previous studies suggest that DNA can be their primary target. Here we show direct evidence that two newly synthesized Ge132 derivatives can intercalate into DNA. Unexpected methyl substitution effect of the novel derivatives on DNA sequence selectivity and cytotoxicity was observed.
Aquaporin-8 (AQP8) is a water-transporting protein expressed in organs of the mammalian gastrointestinal tract (salivary gland, liver, pancreas, small intestine, and colon) and in the testes, heart, kidney, and airways. We studied the phenotype of AQP8-null mice, and mice lacking AQP8, together with AQP1 or AQP5. AQP8-knockout mice lacked detectable AQP8 transcript and protein, and had reduced water permeability in plasma membranes from testes. Breeding of AQP8 heterozygous mice yielded AQP8-null mice, whose number, survival, and growth were not different from those of wild-type mice. Organ weight and serum/urine chemistries were similar in wild-type and AQP8-null mice, except for increased testicular weight in the null mice (4.8 +/- 0.7 vs. 7.3 +/- 0.3 mg/g body wt). Urinary concentrating ability in AQP8-null mice was unimpaired as assessed by urine osmolality (3,590 +/- 360 mosmol/kgH(2)O) and weight loss (22 +/- 2%) after 36-h water deprivation; urinary concentrating ability was similarly impaired in AQP1-null mice vs. AQP8/AQP1 double-knockout mice. Agonist-driven fluid secretion in salivary gland was not different in AQP8 vs. wild-type mice ( approximately 1 microl.min(-1).g body wt(-1)) or in AQP5-null mice vs. AQP8/AQP5 double-knockout mice. Closed intestinal loop measurements in vivo indicated unimpaired osmotically driven water transport, active fluid absorption, and cholera toxin-driven fluid secretion in AQP8-null mice. After 21 days on a 50% fat diet, wild-type and AQP8-null mice had similar weight gain ( approximately 15 g), with no evidence of steatorrhea or abnormalities in blood chemistries, except for mild hypertriglyceridemia in the null mice. The mild phenotype of AQP8-null mice was surprising in view of the multiple phenotype abnormalities found in mouse models of AQP1-5 deficiency.
Urea transporters are a group of proteins that facilitate urea movement across biological membranes. Kidd blood group (Jk antigen) and urea transporter of human erythrocytes are carried by the same protein UT-B. To investigate the molecular basis of the Jk null phenotype in the Chinese population, blood samples from Chinese individuals were screened using the 2 mol/L urea solution hemolysis test. Urea and water permeability of erythrocytes membrane was measured by stopped-flow light scattering. Genomic DNA was extracted from lymphocytes. UT-B gene of JKnnu's family was analyzed using genomic PCR by primers designed to cover sequences of all exons and exon-intron boundaries in human UT-B gene. One Jk null subject was found from twenty thousand screened Chinese individuals, and it was confirmed that this individual did not express the erythrocyte urea transporter. Genomic sequence analysis of the Jk null individual showed that there were two point mutations, G-->C, which is novel, and G-->A, at the 3'-acceptor splice site (AG) of intron 5 of UT-B gene. Exon 6 is spliced out in the UT-B transcript due to either of these mutations. Water permeability in Jk null erythrocytes (Pf, -0.00037 cm/s) was significantly lower than that in normal erythrocytes (Pf, -0.00062 cm/s) after HgCl2 incubation, providing evidence for UT-B facilitated water transport in human erythrocytes.
OBJECTIVE: To study the effects of pSilencer 1.0-U6-siRNA-STAT3 on the growth of PC3 and LNCaP cells. METHODS: Three pairs of DNA template coding siRNA were synthesized against STAT3 to reconstruct pSilencer 1.0-U6-STAT3-siRNA, which was transfected into PC3 and LNCaP cells. The STAT3 expression in PC3 cells and LNCaP were transfected with pSilencer 1.0-U6-siRNA-STAT3, and it was detected by Western blot and Northern blot. MTT and FCM were used to observe the growth-inhibiting ratio and apoptosis in PC3 cells. RESULTS: Western blot and Northern blot analyses demonstrated that pSilencer 1.0-U6-siRNA-STAT3 could significantly inhibit the expression of STAT3 in PC3 and LNCaP cells; MIT and FCM results showed that it could suppress the growth of PC3 cells and LNCaP and induce apoptosis of PC3 cells in vitro. CONCLUSION: PSilencer 1.0-U6-siRNA-STAT3 could significantly inhibit STAT3 expression, suppress the growth of PC3 and LNCaP cells and induce the apoptosis of PC3 cells.
OBJECTIVE: To confirm the expression and distribution of aquaporin 5 (AQP5) in rat nasal mucosa of experimental allergic rhinitis and to investigate the relationship between AQP5 and allergic rhinitis. METHODS: Twenty-four healthy Wistar rats both male and female weighting 200-300 g were divided into two groups randomly, one was testing group (n = 12), the other was comparing group (n = 12). Generally sensitized rats in testing group were given repeated local booster sensitization into nasal cavity. Twelve normal rat nasal mucosa and twelve nasal mucosa from rat with allergic rhinitis were used. The distribution of AQP5 in normal rat nasal mucosa and nasal mucosa in rat with allergic rhinitis were observed by immunofluorescence technique. Furthermore, the expression of AQP5 in normal rat nasal mucosa and nasal mucosa from rat with allergic rhinitis were studied by immunohistochemical staining. RESULTS: Hematoxylin and eosin staining showed that there was obvious inflammation reaction, a large quantity of glands hyperplasia and acidophils soaked in nasal mucosa from rat with allergic rhinitis. (2) Both immunofluorescence technique and immunohistochemical staining showed that the distribution of AQP5 in normal rat nasal mucosa was in accordance with that in nasal mucosa from rat with allergic rhinitis on the whole. AQP5 expressed mainly in the membrane and cytoplasm of the epithelium in the glands, ducts and cilia. (3) The statistical analysis of the immunohistochemical staining showed that the quantity of AQP5 in rat nasal mucosa with allergic rhinitis (156.37 +/- 1.93) was obviously higher than that in the normal rat nasal mucosa (178.52 +/- 1.94). There was statistical significance between the two groups (t = 28.08, P < 0.01). CONCLUSIONS: The hypersecretion of glands has a close relationship with the high expression of AQP5 in allergic rhinitis.
OBJECTIVE: To investigate the role of human estrogen receptor-related receptors (ERRs) in ovarian cancer. METHODS: A green fluorescent protein (GFP) reporter plasmid of ERRalpha was constructed and transfected into ovarian cancer cell lines SKOV3 and OVCAR3. RT-PCR was used to analyze the expression of ERRalpha, ERRbeta, and ERRgamma mRNA in 33 primary ovarian cancer samples and 12 normal ovarian epithelial cells. Progression-free survival time and overall survival time of patients with different expression of ERRs were analyzed by Kaplan-Meier method. RESULTS: GFP-ERRalpha fusion protein showed ERRalpha expressed in the ovarian cancer cell nucleus. Expressions of the ERRalpha and ERRgamma were increased in the ovarian cancers (58% and 48%) compared with the normal ovarian tissues (P < 0.05); ERRbeta was weakly expressed in the ovarian cancer (9%) as well as in the normal tissues (0). Expression of ERRalpha was positively correlated with the International Federation of Gynecology and Obstetrics (FIGO) stage (r = 0.639, P = 0.017) and cell grading (r = 0.520, P = 0.022). Survival analysis showed that ERRalpha positive group had a poorer overall survival (19.0 months vs. 31.5 months, P < 0.05) and ERRgamma positive group had a longer progression-free survival (18.0 months vs. 13.5 months, P < 0.05). CONCLUSIONS: ERRalpha chiefly expresses in the cell nucleus. ERRalpha and ERRgamma may play important roles in ovarian cancer.
OBJECTIVE: To investigate the role of estrogen receptor-related receptor (ERR), a subfamily of orphan receptors, in the tumorigenesis of endometrial carcinoma and to evaluate the clinical significance. METHODS: A total of 46 cases of endometrial carcinoma tissues and 24 cases of normal endometrium tissues were collected. Semi-quantitative reverse transcription polymerase chain reaction and immunohistochemistry were used to measure the expressions of ERR. All samples were classified into two groups according to ERalpha status. RESULTS: It was positively correlated between the ERR (alpha, beta, gamma) mRNA and protein expression (r = 0.462, P = 0.009; r = 0.689, P = 0.016 and r = 0.673, P = 0.001). The expression rate and level of ERRalpha mRNA in ERalpha-positive endometrial carcinoma (42%, 0.24 +/- 0.18) were lower than in normal endometrium (78%, 0.42 +/- 0.23; P = 0.019, P = 0.021). No significant difference was observed in the expression of ERRbeta mRNA between endometrial carcinoma (23%, 0.21 +/- 0.16) and normal endometrium (22%, 0.27 +/- 0.15; P > 0.05). In ERalpha-positive endometrial carcinoma, the expression level of ERRgamma mRNA (0.93 +/- 0.24) was higher than normal endometrium (0.72 +/- 0.21; P = 0.023). The numbers of patients of Federal International Gynecological Oncology (FIGO) stage II-IV and of deep myometrial invasion in ERRalpha mRNA positive endometrial carcinoma group were more than those in ERRalpha mRNA negative group (P = 0.017 and P = 0.033). ERRgamma mRNA positive patients had a lower occurrence of lymph metastases than negative patients (P = 0.021). CONCLUSIONS: ERR may be closely related with the tumorigenesis of endometrial carcinoma, similar to ER. ERRalpha may serve as a biomarker of poor prognosis and ERRgamma as a favorable biomarker in endometrial carcinoma.
OBJECTIVE: To study induction of apoptosis and inhibition of proliferation in Hep-2 by survivin gene targeting. METHOD: Antisense survivin RNA expression vector was constructed and then was transfected to human laryngeal carcinoma cell line Hep-2 by lipofectamine. HpEGFP/survivin cells were abstained by using G418. The level of survivin protein before and after transfection was determined by Western blot. Proliferation activity was measured by MTT assay. The experiment of colony formation in soft agar was carried out. Apoptosis was assessed by flow cytometry and acridine orange (AO). RESULT: After antisense survivin RNA plasmids were transfected, the level of survivin protein was inhibited in Hep-2. Compared with control, proliferation of HpEGFP/survivin cells transfected with the recombinant of antisense survivin RNA were suppressed significantly. The experiment of colony formation in soft agar showed the ability of colony formation decreased in HpEGFP/survivin cells compared to control (P <0.05). Apoptosis rate increased about 1.81 folds compared with control. CONCLUSION: The recombination antisense survivin RNA plasmid can partly inhibit the level of survivin protein expression in Hep-2. Antisense survivin RNA can induce apoptosis and inhibit the proliferation of Hep-2 by down-regulating the expression of endogenous survivin in vitro.
OBJECTIVE: To study the membrane mobility of aquaporin 7 (AQP7) by cloning stably transfected CHO cells with expression of pEGFP-C1-AQP7, in which AQP7 cDNA was fused downstream and in frame to pEGFP-C1 gene. METHODS: The full sequence of AQP7 was amplified by RT-PCR and then recombined in the downstream of the green fluorescent protein gene in the pEGFP-C1 vector. The recombinant vector pEGFP-C1-AQP7 was stably transfected into CHO cells. With fluorescent microscopy, immunocytochemical stain and Western blot, pEGFP-C1-AQP7 showed a predominant intracellular vesicular localization. RESULTS: (1) The sequence of AQP7 cDNA of the Wistar rat was logged into the GenBank (access number: AY157737). (2) Identification demonstrated that pEGFP-C1-AQP7 fusion protein stably expressed in CHO cells. (3) With fluorescence microscopy, pEGFP-C1-AQP7 showed a predominant intracellular vesicular localization. CONCLUSION: The CHO cell line with stable pEGFP-C1-AQP7 expression was set up successfully for advanced research.
Nanocrystalline zirconia co-doped with Yb3+ and Tm3+ ions was prepared by co-precipitation. Up-conversion luminescence of the samples doped with different Tm3+ concentrations was investigated under a 980 nm LD excitation. When x = 0.2 and 0.4, the luminescences of the two samples were mostly the same: strong blue up-conversion peaked at 474 nm and very weak red up-conversion were observed, corresponding to the transitions of 1G4 --> 3H6 and 1G4 --> 3F4 respectively. However, there was no luminescence of x = 1. Blue up-conversion luminescence of 0.2 mol% Tm3+-ions-doped nanocrystalline zirconia under different annealing temperatures was investigated. Blue up-conversion emission grew stronger with annealing temperature increasing. With pumping current increasing, blue up-conversion emission grew stronger too. By studying the sources of blue up-conversion, we concluded that it was three-photon process.
An ordered Si-C alloy was observed in the products resulting from thermal reduction of molybdenum disilicide heating rods. High-resolution transmission electron microscopy measurements indicate that the Si1-xCx alloy with x approximately 25% is pure, single crystalline, and possesses a superlattice structure. The superlattice periodicity occurs along the diamond [001] direction and corresponds to the quintupling of the primary (002) periodicity. The possible growth mechanism is discussed. The Mo element is likely to play a crucial role in the growth process of the Si1-xCx alloy, since it can both reduce the energy required for breaking up C clusters and contribute to surface modification, which are of great benefit to enhance the carbon concentration and induce an ordered structure.
OBJECTIVE: To investigate the protective effects of vitamin B(12), ginseng saponin, and folic acid on mouse embryos subjected to high heat. METHODS: Mice were used for the experiment. RESULTS: After exposure of pregnant mice to high heat, the rates of teratism, stillbirth, and fetal absorption were markedly lower in mice treated with ginseng saponin and folic acid following heat exposure than in untreated mice. There were no significant differences in these rates when comparing mice treated with vitamin B(12) with the untreated mice. CONCLUSIONS: Ginseng saponin and folic acid can lessen injuries to murine embryos caused by high heat, while vitamin B(12) has little protective effect against high temperature except for promoting overall embryonic growth.
OBJECTIVE: To study the effect of zinc L-lysine and taurine against teratogenesis caused by hyperthermia in pregnant mice. METHODS: Eighty seven female Swiss mice with the gestational age of 8 days were exposed to 42.5 approximately 43.0 degrees C waterbath for 9 minutes. Six hours later the same procedure was repeated for 8 minutes. On the 9th gestational day zinc L-lysine (200 mg/kg) was perfused orally into 30 pregnant mice, and taurine (300 mg/kg) was perfused orally into 27 pregnant mice. The other 30 mice were used as controls. On the 18th gestational day, the pregnant mice were all killed. The teratogenic rate, embryo rate, and absorbed embryo rate, body weight, body length, and tail length of each mouse were examined. RESULTS: The teratogenic rates in zinc L-lysine group and taurine group were 1.1% and 1.2% respectively, both significantly lower than that in the control group (5.4%, P < 0.01). The dead embryo rates in the zinc L-lysine group and taurine group were 1.0% and 1.5% respectively, both significantly lower than that in the control group (3.5%, P < 0.01). The absorbed embryo rates in the zinc L-lysine group and taurine group were both 5.6%, significantly lower than that in the control group (14.3%, P < 0.01). The mean weight of the first two groups was 1 370 mg +/- 180 mg and 1 380 mg +/- 190 mg respectively, significantly greater than that in the control group (1 280 mg +/- 240 mg, P < 0.01). The mean body length in the first two groups was 28.1 mm +/- 1.9 mm and 28.0 mm +/- 2.1 mm respectively, significantly greater than that in the control group (26.7 mm +/- 2.2 mm, P < 0.01). The mean tail length in the first two groups was 12.2 mm +/- 1.3 mm and 12.2 mm +/- 1.9 mm respectively, significantly greater than that in the control group (11.6 mm +/- 1.5 mm, P < 0.01). CONCLUSION: Zinc L-lysine and taurine have a significant effect against teratogenesis caused by hyperthermia and promote the embryo growth.