Biomedical subjects

Cheng Chang

Publications and source records attributed to Cheng Chang.

29 records · Page 2Linked to original sources

PubMed2005

[The expression and clinical significance of stromal cell-derived factor-1 and CXCR4 in acute leukemia and malignant lymphoma].

OBJECTIVE: To analyze the expression of stromal cell derived factor-1 (SDF-1) and its functional chemokine receptor CXCR4 in patients with acute leukemia and malignant lymphoma. METHODS: CXCR4 expressed on the membrane surface of marrow mononuclear cells was enumerated with 3-color flow cytometry. The serum level of SDF-1 was determined with ELISA assay. RESULTS: The expression of SDF-1 and CXCR4 in acute leukemia for ALL group, the expression of SDF-1 and CXCR4 is (7115.8 +/- 946.5) ng/L and (77.2 +/- 9.7)%; for ANLL group, the expression is (4642.2 +/- 1146.8) ng/L, (38.9 +/- 11.0)% and malignant lymphoma for HD group, the expression of SDF-1 and CXCR4 is (3728.9 +/- 690.9) ng/L and (9.2 +/- 2.7)%; for NHL group, the expression is (4442.1 +/- 1073.0) ng/L and (8.5 +/- 2.4)% patients were higher than that in controls the expression of SDF-1 and CXCR4 is (2369.3 +/- 966.5) ng/L and (2.7 +/- 1.5)% (P < 0.01). In the leukemia group, the patients with extra-marrow infiltration have higher expression of SDF-1/CXCR4 than those without and the patients; in the lymphoma group. CONCLUSIONS: The high expression of SDF-1 and CXCR4 is somewhat correlated with the pathogenetic process and infiltration characteristics of acute leukemia and malignant lymphoma. This can provide a new method to cure the above-mentioned hematologic tumors.

Adolescent↗

PubMed2005

[Effects of RNA interference inhibiting SDF-1 expression in bone marrow stromal cells on the proliferation and apoptosis of co-cultured Jurkat cells].

OBJECTIVE: To study the effects of RNA interference inhibiting stromal cell derived factor-1 (SDF-1) expression on the proliferation and apoptosis of co-cultured Jurkat cells. METHOD: Inhibition of SDF-1 expression by RNA interference (RNAi) was achieved by transferring SDF-1 specific short hairpin RNA (shRNA) expressing plasmid into cultured human acute leukemic bone marrow stromal cells. Resistant clones were obtained by G418 selection (group A). The concentration of SDF-1 protein in culture supernatant was detected by enzyme-linked immunosorbent assay (ELISA). The population double time (PDT), cell cycles, apoptosis rates and the expressions of PCNA, Bcl-2/Bax, Fas/FasL of co-cultured Jurkat cells were detected by cells counting, flow cytometry. TdT-mediated dUTP nick-end labelling (TUNEL) and immunocytochemistry (ICC), respectively. The un-transfected acute leukemic (group B) and normal (group C) bone marrow stromal cells were taken as controls. RESULTS: The content of SDF-1 protein in supernatant of group A\[(384 +/- 41) pg/ml] was significantly lower than that in group B[(2474 +/- 271) pg/ml] or group C[(1324 +/- 154) pg/ml]. As group A compared with group B and group C, the PDT of co-cultured Jurkat cells was prolonged (group A: 42 h, vs group B: 29 h, group C: 33 h), and G(0)/G(1) stage cells increased [group A: (28.47 +/- 2.39)%, vs group B: (19.43 +/- 2.80)%, group C: (27.15 +/- 2.07)%], S stage cells decreased [group A: (25.57 +/- 1.90)%, vs group B: (74.48 +/- 3.23)%, group C: (60.99 +/- 2.33)%], G(2)/M stage cells increased [group A: (45.96 +/- 3.24)%, vs group B: (6.09 +/- 1.96)%, group C: (11.86 +/- 1.98)%], the apoptosis rate increased [group A: (15.2 +/- 0.8)%, vs group B: (5.4 +/- 0.7)%, group C: (9.5 +/- 0.4)%], and the expressions of PCNA, Bcl-2, Fas decreased; whereas the expressions of Bax and FasL were increased. CONCLUSION: The inhibition of SDF-1 expression in bone marrow stromal cells inhibits the proliferation and promotes the apoptosis of co-cultured Jurkat cells.

Apoptosis↗

PubMed2005

[Effects of inhibiting SDF-1 expression by RNA interference on adhesion and drug sensitivity of Jurkat cells co-cultured with bone marrow stromal cells].

OBJECTIVE: To observe the effects of inhibiting stromal cell derived factor-1 (SDF-1) expression by RNA interference (RNAi) on adhesion and drug sensitivity of Jurkat cells co-cultured with bone marrow stromal cells. METHODS: SDF-1 specific short hairpin RNA (shRNA) expressing plasmid was transferred into cultured human acute leukemic bone marrow stromal cells, positive clones were isolated by screening G418 resistance (Group A) , SDF-1 protein level in culture supernatant was detected by enzyme-linked immunosorbent assay (ELISA). The adhesion rates to bone marrow stromal cells layer and the drug sensitivity to doxorubicin of co-cultured Jurkat cells were detected by cell counting and MTT assay, respectively. The un-transfected bone marrow stromal cells of acute leukemia patient (Group B) or normal subject (Group C) were taken as control. RESULTS: The level of secreted SDF-1 protein (pg/10(5) cells/week) in the supernatants of Group A, B and C were 1920 +/- 205, 12,370 +/- 1355 and 6620 +/- 770, respectively. Of co-cultured Jurkat cells in Group A, B and C, the adhesion rates after 24 h co-culturing were (28.8 +/- 2.6)%, (57.4 +/- 3.8)% and (45.2 +/- 4.0)%, respectively, and the IC50 values of doxorubicin were 585, 6162 and 1758 nmol/L, respectively. CONCLUSION: Down-regulating SDF-1 expression of bone marrow stromal cells by RNAi reduces adhesion rates and enhances drug sensitivity to doxorubicin of their co-cultured Jurkat cells.

Bone Marrow Cells↗

PubMed2004

Topology scanning and putative three-dimensional structure of the extracellular binding domains of the apical sodium-dependent bile acid transporter (SLC10A2).

The apical sodium-dependent bile acid transporter (ASBT, SLC10A2) facilitates the enterohepatic circulation of bile salts and plays a key role in cholesterol metabolism. The membrane topology of ASBT was initially scanned using a consensus topography analysis that predominantly predicts a seven transmembrane (TM) domain configuration adhering to the "positive inside" rule. Membrane topology was further evaluated and confirmed by N-glycosylation-scanning mutagenesis, as reporter sites inserted in the putative extracellular loops 1 and 3 were glycosylated. On the basis of a 7TM topology, we built a three-dimensional model of ASBT using an approach of homology-modeling and remote-threading techniques for the extramembranous domains using bacteriorhodopsin as a scaffold for membrane attachment points; the model was refined using energy minimizations and molecular dynamics simulations. Ramachandran scores and other geometric indicators show that the model is comparable in quality to the crystal structures of similar proteins. Simulated annealing and docking of cholic acid, a natural substrate, onto the protein surface revealed four distinct binding sites. Subsequent site-directed mutagenesis of the predicted binding domain further validated the model. This model agrees further with available data for a pathological mutation (P290S) because the mutant model after in silico mutagenesis loses the ability to bind bile acids.

Amino Acid Sequence↗

PubMed2004

A ligand-based approach to identify quantitative structure-activity relationships for the androgen receptor.

We examined the three-dimensional quantitative structure-activity relationship (QSAR) of a group of endogenous and synthetic compounds for the androgen receptor (AR) using comparative molecular field analysis (CoMFA). The goal of these studies was to identify structural features necessary for high binding affinity and optimization of selective androgen receptor modulators (SARMs). A homology model of the AR was used as a scaffold to align six lead compounds that served as templates for alignment of the remaining 116 structures prior to CoMFA modeling. The conventional r(2) and cross-validated q(2) relating observed and predicted relative binding affinity (RBA) were 0.949 and 0.593, respectively. Comparison of predicted and observed RBA for a test set of 10 compounds resulted in an r(2) of 0.954, demonstrating the excellent predictive ability of the model. These integrated homology modeling and CoMFA studies identified critical amino acids for SARM interactions and provided QSAR data as the basis for mechanistic studies of AR structure, function, and design of optimized SARMs.

Anilides↗

PubMed2004

[Inhibiting effects of stroma cell drived factor 1 (SDF-1) on proliferation of human acute myelocytic leukemia cell HL-60].

This study was aimed to investigate the importance of chemokine SDF-1 in maintaining proliferation ability of acute myelocytic leukemia cell line HL-60 when the effects of SDF-1 on HL-60 cell proliferation were inhibited. Marrow stromal cells were cultured and co-cultured with HL-60 cells, and SDF-1 activity was blocked with anti-CXCR4 McAb. HL-60 cell activity was detected by MTT while cell cycle and the expression of CXCR4 on HL-60 cell membrane were observed by flow cytometry meanwhile. The internal calcium ionic concentration in HL-60 cell was detected as well before and after treated with 12G5. The results showed that 12G5 down-regulated the expression of CXCR4 on HL-60 cell membrane; HL-60 cells at G(0)/G(1) phase increased, but decreased at S phase; survive rate of leukemia cells reduced; the intercellular calcium ionic concentration of HL-60 cell decreased after treated with 12G5. It was concluded that brockage of the SDF-1 activity may inhibit proliferation of leukemia cell at certain level.

Antibodies, Monoclonal↗

PubMed2004

[Effects of anti- CXCR4 monoclonal antibody on adhesiveness of human acute myelocytic leukemia cell line HL-60 and expression of Bcl-2, Fas proteins].

To study the importance of chemokine SDF-1 in surviving of acute myelocytic leukemia cells HL-60, the adhesion ability of HL-60 and expression of Bcl-2, Fas protein when SDF-1 activity was blocked by anti-CXCR4 monoclonal antibody (12G5) were compared with those detected before MAb incubation, in this experiment, HL-60 cell were cultured and co-cultured with normal marrow stromal cell. The adhesion rate was detected while the expression of Bcl-2 and Fas proteins were assayed by immunohistochemical technique when SDF-1 activity was inhibited. The results showed that cell adhesion rate of HL-60 decreased while the expression Bcl-2 decreased and Fas increased. It is concluded that inhibition of SDF-1 activity increases cell apoptosis and thus reduces life-span of leukemia cell at certain level.

Antibodies, Monoclonal↗

PubMed2004

[Molecular identification of wheat granule bound starch synthase gene polymorphism].

Fourteen wheat cultivars were identified into six types of Wx proteins combinations using 6% SDS-PAGE. PCR primers were designed according to the three Wx genes sequences and their mutants, respectively. A 327 bp-band was amplified from the Wx-A1 mutant,while the band was absent for the normal alleles at the Wx-A1 locus,as well as the presence or absence of a 187 bp PCR fragment at the Wx-B1 locus and a 700 bp PCR fragment at the Wx-D1 locus, respectively, corresponding to the normal and mutant alleles. Compared with the former studies, shorter and more different PCR products at three loci, amplified by the primers designed for Wx-B1 gene can be separated in 2% agarose gel, which enables screening breeding lines for noodle use faster and effectively.

Electrophoresis, Polyacrylamide Gel↗

PubMed2004

[Effects of anti-CXCR4 monoclonal antibody on adhesion and proliferation of human acute myelocytic leukemia cell line HL-60].

BACKGROUND & OBJECTIVE: Stromal cell derived factor-1 (SDF-1), excreted by bone marrow stromal cells, may be involved in shielding of marrow stromal cells from leukemia cells by binding to its receptor CXCR4, but the relation between SDF-1/CXCR4 axis and leukemia cells is unclear. This study was to inhibit activity of SDF-1 by anti-CXCR4 monoclonal antibody 12G5, observe changes of adhesion and proliferation of acute myelocytic leukemia cell line HL-60 co-cultivated with leukemic marrow stromal cells, and to assay potential of inhibiting SDF-1-driven processes on treating marrow residual disease. METHODS: HL-60 cells were co-cultured with leukemic marrow stromal cells, and 10 mug/ml 12G5 was added to block SDF-1 activity. Adhesive state, adhesion rate, apoptosis rate, and cell cycle of HL-60 cells were observed after incubation. Living conditions of HL-60 cells were detected by trypan blue exclusion, cell growth curve was protracted. RESULTS: Adhesion rate of 24-h 12G5-incubated HL-60 cells was (39.4+/-7.9)%, while that of control HL-60 cells was (51.4+/-5.9)% (P< 0.05). G0/G1, S, and G2/M phases of 24-h 12G5-incubated HL-60 cells were (55.2+/-4.9)%, (30.4+/-4.1)%, and (14.4+/-5.2)%, respectively, and apoptosis rate was (9.0+/-1.7)%; while those of control HL-60 cells were (44.7+/-2.2)%, (45.3+/-3.7)%, (10.0+/-2.6)%, and (4.0+/-2.4)%, respectively. T test showed that 12G5 induced more cells entering G0/G1 phase (P< 0.05), and increased cell apoptosis rate(P< 0.05). Compared with control HL-60 cells, survival rate and proliferation of 48-h 12G5-incubated HL-60 cells decreased markedly. CONCLUSION: 12G5 may inhibit adhesion ability and proliferation of HL-60 cells, thus inhibiting SDF-1 activity by 12G5 may be helpful to the treatment of marrow residual disease.

Antibodies, Monoclonal↗

PubMed2003

Effects of ultraviolet B on epidermal morphology, shedding, lipid peroxide, and antioxidant enzymes in Cope's rat snake (Elaphe taeniura).

Cope's rat snakes (Elaphe taeniura) favor to expose under sunlight in order to increase their body temperature simultaneously increasing the risk of skin damage by ultraviolet B (UVB) irradiation. We have investigated the effects of UVB irradiation on their skin. Results show that the UVB transmission of the keratinous layer was only 5.1+/-0.36%. The peak of epidermal damage and malondialdehyde (MDA) content, a product of lipid peroxidation, simultaneously occurred 72-96, 48 or 24 h after exposure to 300, 500 and 800 mJ/cm2 of UVB radiation, respectively. Superoxide dismutase (SOD) activity was inhibited by UVB and the lowest activity occurred 24, 48, 12 and 12 h after exposure to 110, 300, 500 and 800 mJ/cm2 of UVB, respectively. SOD activity recovered later to some extent but mostly remained below control level. After exposure to different doses of UVB radiation, catalase (CAT) activity was inhibited immediately, and then gradually recovered and even increased to peak levels above control level. The highest CAT levels accompanied the most serious damage of skin morphology. Later on, CAT activity decreased and recovered again close to or below control level, which was accompanied by shedding off the damaged epidermal complex. This indicated that the epidermal damage induced by UVB is closely related to lipid peroxidation, where CAT acts as a primary antioxidant enzyme. Moreover, the keratinous layer protects the viable cell layer against UVB damage as well.

Animals↗

PubMed2003

Structural determinants of P-glycoprotein-mediated transport of glucocorticoids.

PURPOSE: The aim of this study was to determine requisite structural features for P-glycoprotein-mediated transport of a series of structurally related glucocorticoids (GCs). METHODS: Transport experiments were conducted in wild-type and stably transfected MDRI LLC-PK cell line. Transport efficiency (Teff = Peff, B-->A / Peff, A-->B) in both cell lines was compared as a measure of passive diffusion and P-glycoprotein-mediated transepithelial transport for each steroid. Three-dimensional structure-activity relationships were built to determine how specific structural features within the steroids affect their P-gp-mediated efflux. RESULTS: Mean (+/- SD) Teff in LLC-PK cells was 1.1 +/- 0.17, indicating that differences in structure and partition coefficient did not affect drug flux in the absence of P-glycoprotein. Teff in L-MDRI cells ranged from 3.6 to 26.6, demonstrating the importance of glucocorticoid structure to P-glycoprotein transport. The rank order of Teff in MDR1 cells was: methylprednisolone> prednisolone > betamethasone > dexamethasone/prednisone > cortisol. There was no correlation between individual Teff values and partition coefficient. 3D-QSAR models were built using CoMFA and CoMSIA with a q2 (r2) of 0.48 (0.99) and 0.41 (0.95), respectively. CONCLUSIONS: Nonpolar bulky substituents around the C-6alpha position, as well as a hydrogen-bond donor at position C-11, enhance P-glycoprotein affinity and cellular efflux, whereas bulky substituents at C-16 diminish transporter affinity.

ATP Binding Cassette Transporter, Subfamily B, Mem↗