[Effect of calmodulin antagonist O-4-ethoxyl- butyl-berbamine on the proliferation of human breast cancer cell line MCF-7 and its relevant mechanism].

OBJECTIVE: To investigate the effect of calmodulin antagonist O-(4-ethoxyl-butyl)-berbamine (EBB) on proliferation of human breast cancer cell MCF-7 and its possible mechanism. METHODS: MTT assay was used to analyze the effect of EBB on tumor cells growth. Flow cytometry was used to detect its impact on the cell cycle of MCF-7 cells. Immunofluoresce labeling technique and laser scanning confocal microscope were used to reveal the changes of the microtubule, microfilament, mitochondrion, and endoplasmic reticulum in the cells. RESULTS: The IC50 value of EBB in MCF-7 cells was (13.0 +/- 3.7) micromol/L. MCF-7 cells were arrested at S phase after EBB treatment. Meanwhile, depolymerization of the microtubule and microfilament, impairment of the mitochondrion and swelling of endoplasmic reticulum were observed. CONCLUSION: EBB arrests MCF-7 cells at S phase by inhibiting the growth of MCF-7 cells, which may be related to the changes of structures and functions of the microtubule, microfilament, mitochondrion, and endoplasmic reticulum.

[Three-step purification of preparative-scale antiCD20 (Fab')2].

OBJECTIVE: To establish a three-step purification method of preparative-scale antiCD20 (Fab')2 using AKTA prime. METHODS: AntiCD20 (Fab')2 was extracted by hyperosmotic solution and then purified by CM sepharose FF, phenyl sepharose FF, and protein G sepharose FF. RESULTS: Around 8 mg anti-CD20 (Fab')2, whose purification was 96.678%, was purified. The antigen-binding activity of antiCD20 (Fab')2 was similar to that of antiCD20 (Fab')2 purified by protein G sepharose FF and S-100. CONCLUSION: The three-step purification method can obtain high-purity preparative-scale antiCD20 (Fab')2 in a simple way.

[Preparation and activity detection of monoclonal antibody against anti-CD3 ScFv].

OBJECTIVE: To prepare monoclonal antibody (McAb) against anti-CD3 ScFv for purifying and detecting serum anti-CD3 antibody concentration. METHODS: McAb against anti-CD3 ScFv was prepared by hybridoma technique and used to prepare affinity chromatography column, which was used to purify anti-CD3 ScFv and Diabody [CD3 x Pgp] without E-tag. The binding activities of anti-CD3 ScFv, Diabody [CD3 x Pgp] without E-tag, and Diabody [CD3 x Pgp] purified by anti-CD3 affinity chromatography column or anti-E-tag affinity chromatography column against K562/A02 cell and Jurket cells were detected by fluorescence activated cell sorting (FACS) method. ELISA was used to identify the specificity of the McAb. RESULTS: McAb against anti-CD3 ScFv specifically detected serum anti-CD3 ScFv without reacting with sera. The anti-CD3 ScFv purified by anti-CD3 affinity chromatography column and purified by anti-E-tag affinity chromatography column had the same specific binding activity with Jurkat cells. The positive binding rates of Diabody [CD3 x Pgp] without E-tag to K562/A02 and Jurkat cells were 89.87% and 83.95%, respectively. In the competitive binding experiments with K562/A02 and Jurkat cells, the binding rates of Diabody [CD3 x Pgp] without E-tag decreased to 56.30% and 43.78%, respectively. CONCLUSION: The McAb against anti-CD3 ScFv prepared in our lab can be used to purify and detect serum anti-CD3 antibody concentration.

[Design and activity determination of small molecular inhibitors of integrin alphavbeta3].

OBJECTIVE: To explore the design and activity determination of small molecular inhibitors of integrin alphavbeta3 through structure-based virtual screening. METHODS: Based on the crystal structure of integrin ctv33 extracellular segment in complex with an ARG-GLY-ASP ligand, docking procedure against the receptor binding domain was performed on 3D database. Integrin alphavbeta3-mediated cell adhesion assay was performed to assess the adhesion-inhibiting ability of the candidate compounds. Cell migration assay and capillary-structure-like formation inhibition assay were used to estimate the effects of the compounds on integrin alphavbeta3. Analysis of molecular graphics was carried out to deduce a probable binding model of compound with integrin alphavbeta3. RESULTS: From the top 1000 compounds with the best DOCK energy score, 50 compounds were selected for biological assay based on chemical and drug-like diversity. Seven of 50 compounds showed notable inhibition activity on cell adhesion, and two with half-maximum inhibition concentration (IC50) values less than 100 mol/L. The compound with best activity (1-37) showed high inhibitory activity in cell migration assay and capillary-structure-like formation inhibition assay. Molecular graphics analysis indicated that metal ion-dependent adhesion site (MIDAS) might be involved in the compound 1-37-mediated inhibition of ligand binding with integrin alphavbeta3. CONCLUSIONS: Through virtual screening combined with biological assay, a promising lead compound was discovered to inhibit integrin alphavbeta3, which embodies the rational drug design with computation aid and brings a new thought and approach to find novel inhibitors of integrin.

[Reversal of multidrug resistance in drug-resistant human breast cancer cell line MCF-7/ADR by calmodulin antagonist O-(4-ethoxyl-butyl)-berbamine].

OBJECTIVE: To investigate the reversal effect of O-(4-ethoxyl-butyl)-berbamine (EBB) on multidrug resistance (MDR) in MCF-7/ADR cell. METHODS: 3-(4, 5-dimethyl-2-thiazolyl)-2, 5-diphenyl-2H-tetrazolium bromide (MTT) assay was used to assess the antitumor effect of EBB and determine the reversal effects of different concentrations ( < or = IC20) of EBB on MCF-7/ADR cell. Flow cytometry was applied to observe the intracellular accumulation of Rh123 and cell cycle in the presence of EBB. The expressions of MDR-related genes mdr 1 and topoisomerase II b (top II b) were evaluated by reverse transcription-polymerase chain reaction. RESULTS: The sensitivity of MCF-7/ADR to adriamycin (ADR) was enhanced up to 50. 40, 89.80, and 14.88 folds after exposure of the cells to 3 micromol/L EBB, 7.5 micromol/L EBB, and 10 micromol/L verapamil (VPL), respectively. After 2 hours of incubation with 6 micromol/L EBB, intracellular Rh123 accumulation in MCF-7/ADR cells was increased to the level comparable to that in MCF-7 cells. When 6 micromol/L EBB was added together with 2 micromol/L ADR, MCF-7/ ADR cells showed to be arrested in the G2/M phase. The declination of mdr 1 gene expression was observed when 6 micromol/L EBB, 12 micromol/L EBB, and 10 micromol/L VPL were added for 48 hours; meanwhile, the expression of top II b mRNA showed no significant change. CONCLUSION: EBB has a strong reversal effect on MDR in MCF-7/ ADR cell, which may be achieved by enhancing the arrestment of MCF-7/ADR cells at G2/M phase and increasing intracellular drug concentration.

[An anti-P-gp/anti-CD3 bispecific antibody cytotoxic to human multidrug resistant KB cells].

OBJECTIVE: To study the specific cytotoxicity mediated by anti-P-gp/anti-CD(3) diabodies in multidrug resistant solid tumor using P-gp as target. METHODS: The anti-P-gp/anti-CD(3) diabodies were secreted from E. coli strain 16C9 containing the expression plasmid PAYZDCP, grown at 30 degrees C in a shaker flask; the diabodies were purified by affinity chromatography and identified by SDS-PAGE; the effect of the anti-P-gp/anti-CD(3) diabody mediated lysis of P-gp-expressing tumor cells was assayed by (51)Cr release assay in vitro, and by human KB nude mouse xenograft models in vivo. RESULTS: The diabodies were generated by bacteria as a soluble functional form and purified by one-step affinity chromatography with a yield > 4 mg/L culture medium. In (51)Cr release assay, the diabodies targeted human activated T cells to lyse P-gp(+)-KB/MDR cells in a dose-dependent manner. It suggested that the diabody was able to induce an efficient lysis of the target cells by human T cells in vitro. When combined with activated human T cells, the diabody significantly inhibited the growth of KB/MDR, but had no effect on KB xenografts. CONCLUSION: The anti-P-gp/anti-CD(3) bispecific antibody is a potent agent for targeting human T lymphocytes to lyse solid tumor cells overexpressing P-gp in vitro and in vivo.

[Effect of monoclonal antibody against extracellular domain III of vascular endothelial growth factor receptor KDR on proliferation of vascular endothelial cells].

OBJECTIVE: To prepare a neutralizing monoclonal antibody (McAb) against vascular endothelial growth factor receptor KDR and study its biological activity. METHODS: Extracellular immunoglobulin (Ig)-like domain III of KDR (KDR III) was expressed in E. coli and purified by affinity chromatograph. Monoclonal antibody against KDR III was prepared by hybridoma technique. ELISA and FACS analysis were used to identify its specificity. Immunoprecipitation and [(3)H]-TdR incorporation assay were also used to detect the activity of anti-KDR McAb blocking the phosphorylation of KDR tyrosine kinase receptor and the influence on VEGF-induced mitogenesis of human endothelial cells. RESULTS: McAb Ycom1D3 against KDR III was prepared which bound specifically to both the soluble KDR III and the cell-surface expressed KDR. It effectively blocked VEGF/KDR interaction and inhibited VEGF-stimulated activation of KDR expression on human endothelial cells. Furthermore, Ycom1D3 efficiently neutralized VEGF-induced mitogenesis of human umbilical vascular endothelial cells. CONCLUSION: McAb Ycom1D3 against KDR III may suppress the action of VEGF by blocking native vascular endothelial growth factor receptor KDR. It has potential clinical applications in the treatment of cancers and other diseases where pathological angiogenesis is involved.

[Effect of calmodulin antagonist EBB on invasion of human fibrosarcoma cell HT1080].

OBJECTIVE: To investigate the potential effect of EBB, a calmodulin antagonist, on invasion of human fibrosarcoma cells HT1080. METHODS: The antitumor effect of EBB was assessed by 3-(4,5-Dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) assay. Activities of matrix metalloproteinase (MMP)-2 and MMP-9 were measured by Zymogrophy analysis. The mRNA levels, of MMP-2, MMP-9, and tissue inhibitor of metalloproteinases (TIMP)-1 were evaluated by reverse transcriptionpolymerase chain reaction (RT-PCR). Transwell chamber assay was applied to measure the effect of EBB on the invasion of HT1080 cells. RESULTS: Calmodulin antagonist EBB inhibited the proliferation of HT1080 cells with an IC50 of (8.2 +/- 1.2) microg/ml. EBB down-regulated the activities of MMP-2 and MMP-9, and down-regulated the mRNA levels of MMP-2 and MMP-9, while up-regulated the mRNA levels of TIMP-1. The invasive ability of HT1080 cells was decreased to (31.13 +/- 2.265)%, (59.91 +/- 2.566)%, and (71.58 +/- 0.5960)% after exposure of the cells with 2, 5, and 10 microg/ml EBB, respectively. CONCLUSION: Treatment with calmodulin antagonist EBB is effective in suppressing tumor invasion. The possible mechanism is the down-regulation of MMPs.

[Identification of differentially expressed genes involved in multidrug resistance in K562/A02 by cDNA microarray].

OBJECTIVE: To study the molecular mechanism underlying multidrug resistance (MDR) and identify unknown genes that might be involved in drug resistance development in K562/A02 cells. METHODS: K562/A02 was induced by gradually increasing the ADM concentration in culture medium of K562 cells, the differential expression of associated genes between K562 and K562/A02 was determined with cDNA microarray. Overexpression of neurofilament protein NF-H gene in K562/A02 cells was confirmed with RT-PCR and immunocytochemistry. Anti-sense oligodeoxynucleotides were transfected into K562/A02 cells by lipofectamine in order to further analyze the role of NF-H in drug resistance. RESULTS: Comparing with the expression profiles, we found upregulation of 5 transcripts and downregulation of 7 transcripts in response to MDR of K562/A02 cells. The overexpression of NF-H, one of the 5 upregulated genes, was confirmed. After being treated with antisense oligodeoxynucleotides of NF-H and mdr1, the cellular adriamycin concentration increased significantly, but antisense NF-H alone did not have significant effect on drug resistance phenotype. CONCLUSION: The development of MDR in K562/A02 cells is multifactorial. NF-H may be involved in the drug resistance of K562/A02, which may provide a new marker of diagnosis and a new target of therapy.

[Effects of 3-substituted aryl oxindole(PH II-7) on cell cycle of tumor cells].

AIM: To study the antitumor mechanism of 3-substituted aryl oxindole (PH II-7) and determine its effects on cell cycle distribution of tumor cells. METHODS: The cell cycle distributions were determined with FACS. The cell cycle regulation-related proteins of K562 lysates were analyzed with Western Blot. The inhibition of PH II-7 on DNA synthesis of tumor cells were estimated though 3H-thymidine incorporation and the tyrosine kinase activity of EGFR of A431 lysates was measured with ELISA. RESULTS: PH II-7 effected cell cycle distribution of several tumor cells, including multidrug resistant tumor cell lines, and accumulation of cells in the G0-G1 stages was observed. The cell cycle regulation-related proteins CDK2, Rb and c-myc were inhibited by PH II-7 in a dose dependent manner, whereas the expression of CyclinE was increased after exposure to PH II-7. Furthermore, PH II-7 2.0 mg.L-1 was shown to inhibit the incorporation of 3H-thymidine into DNA, and 21.89%-41.29% of the PTK activity of EGFR in A431 lysates was inhibited by PH II-7 2-8 mg.L-1 in a dose-dependant manner. CONCLUSION: PH II-7, a new anti-tumor agent, blocks the transition of cell cycle of tumor cells from G1 to S phase by inhibition CDK2.

[Structure-based design, synthesis and evaluation of bioactivity of anti-P-gp peptide mimetic].

AIM: To design and evaluate the small peptide mimetic of anti-P-glycoprotein (P-gp) antibody (PHMA02). METHODS: From the three dementional structure analysis of computer modeling of PHMA02 CDR loops, a small peptide mimetic was designed and determined by flow cytometry. RESULTS: Anti-P-gp peptide mimetic functionally similar to PHMA02 was developed. The peptide mimetic competitively inhibits PHMA02 binding to P-gp and partially block the P-gp function as a drug efflux pump in K562/A02 cells. CONCLUSION: Some special conformational properties of CDR loops of antibody might serve as lead structures for develop new biological peptide mimetics. Antibody-structure-based design would develop new drug in the future.

[Preliminary studies on the mechanisms of a new anti-tumor agent PH II-7 with special preference to multidrug resistant tumor cells].

OBJECTIVE: To determine the anti-tumor activity of PH II-7 in vitro and explore preliminarily its mechanisms. METHODS: The anti-tumor activity was measured using colorimetric MTT assay. Apoptosis was determined with fluorescence-activated cell sorter (FACS), electron microscopy and agarose gel electrophoresis. The expressions of mdr1 and sorcin genes were determined by Northern blot assay. RESULTS: PH II-7 inhibited the proliferation of various human tumor cells derived from different tumor cell lines. The IC50 values varied from 0.34-18.61 mumol/L. Especially, PH II-7 had strong inhibitory effect on multidrug resistant tumor cells, whereas adriamycin (ADR) was resistant. Apoptosis was induced in HL60 and HL60/ADR cells treated with 1 microgram/ml PH II-7, while PH II-7 inhibited the expressions of mdr1 and sorcin genes. CONCLUSIONS: PH II-7 is a new potential agent which has strong inhibitory effect on both multidrug resistant cells and their parental cells. PH II-7 may increase the intracellular drug concentration in MDR cells by inhibiting the expressions of the MDR-related genes mdr1 and sorcin and induce the apoptosis of MDR cells and their parental tumor cells.

[Molecular design and biological activity of BCR-ABL tyrosine kinase inhibitors].

OBJECTIVE: To discover BCR-ABL tyrosine kinase inhibitors through structure based virtual screening. METHODS: Docking screening against the distinctive inactive conformation of the catalytic domain of BCR-ABL tyrosine kinase was performed on 3D database. The MTT assay was performed to assess the viability of the tumor cells treated with selected compounds. The amount and kinase activity of BCR-ABL protein were detected in the presence of compounds by Western blot analysis and immunoprecipitation. RESULTS: From the top 1,000 compounds with the best DOCK energy score, 15 compounds were selected for biological assay. Eight out of 15 compounds showed notable inhibitory activity against Ph+ human K562 cells with IC50 values ranging from 10 to 200 micromol/L. In cell-based assays of ABL tyrosine phosphorylation, the ability of two kinds of novel, structurally diverse, lead compounds to inhibit ABL kinase activity was observed. However, no significant differences in the amount of BCR-ABL protein were noted on the ABL immunoblot in the presence of these lead compounds. CONCLUSIONS: Two promising lead compounds were discovered to inhibit BCR-ABL tyrosine kinase activity. Virtual screening technique has been proven to narrow down the size of screening compound libraries to the most prospective drug candidates with high success rates.

A review of ERGIC-53: its structure, functions, regulation and relations with diseases.

ERGIC-53 is a type I transmembrane protein. It includes an N-terminal signal sequence, a carbohydrate recognition domain, which is calcium-dependent and pH-sensitive, a stalk region, a transmembrane domain, and a short cytoplasmic domain; ERGIC-53 mainly acts as a receptor of a limited number of glycoprotein and transports them from ER to ERGIC and Golgi, meanwhile it has a secondary glycoprotein quality control function. Recent research has revealed that UPR, heat shock and VIPL may regulate the expression of ERGIC-53. F5F8D, and some ER storage diseases have relationship with ERGIC-53.

Haishengsu as an adjunct therapy to conventional chemotherapy in patients with non-small cell lung cancer: a pilot randomized and placebo-controlled clinical trial.

OBJECTIVE: To investigate the effect of Haishengsu, an extract from Tegillarca granosa, on non-small cell lung cancer as an adjunct to conventional chemotherapy. DESIGNS/SETTINGS: Randomized, double-blind, placebo-controlled trial was conducted in 83 patients. The Haishengsu (n=42, 2.4mg Haishengsu in 250ml normal saline, iv, for 15 days) and the placebo group (n=41, 250ml normal saline, iv) were also treated with two cycles (28 days for each cycle) of conventional chemotherapy consisting mitomycin, vindesine and cisplatin. RESULTS: The curative effect of conventional chemotherapy was observed in 62% of Haishengsu group patients and in 39% in of the placebo group patients (P=0.04, RR 1.59, 95% CI: 1.01-2.49). Improvement in Karnofsky performance status scores was seen in 66.7% of Haishengsu group patients and in 17.1% of the placebo group patients (P<0.01, RR 3.63, 95%CI: 1.77-7.41). The ratio of patients with no or only mild gastrointestinal reaction in the Haishengsu and the placebo group was 83.3% and 39.0%, respectively (P<0.01, RR 2.13, 95% CI: 1.42-3.20). CONCLUSIONS: This study suggests that Haishengsu may be an effective adjunct therapy to the conventional chemotherapy for non-small cell lung cancer. The short-term therapeutic effect of chemotherapy may be improved and the chemotherapy-induced nausea or vomiting may be reduced by concurrent Haishengsu administration.

[The influence of Ara-C on anti-CD3/anti-Pgp mediating T-lymphocytes activities against multi-drug resistant leukemia cells.].

OBJECTIVE: To investigate the role of Ara-C in regulating anti-CD3/anti-Pgp mediating T-lymphocytes activities against multi-drug resistant leukemia cells. METHODS: The diabody of anti-CD3/anti-Pgp was purified by E-tag affinity chromatography. K562 and K562/A02 cells were treated with Ara-C. The expressions of B7-1 and B7-2 on K562 and K562/AO2 cells were detected by FACS. The cytotoxicity of T-lymphocytes combined with anti-CD3/anU-Pgp plus Ara-C was analyzed by CytoTox 96 nonradioactive method. RESULTS: The expressions of B7-1 and B7-2 on K562 and K562/A02 cells treated by Ara-C was significantly higher than those untreated. The effect/target ratio was from 0.39:1 to 25:1, and the killing rate of activated T cells to anti-drug-resistant leukemia cells was from (16.44 +/- 1.20)% to (60.49 +/- 2.90)%. The killing rates were increased gradually, with both the effect/target ratio and the antibody concentration increasing (P < 0.05). CONCLUSION: Ara-C may be an important adjuvant for improving anti-CD3/anti-Pgp mediating T-lymphocytes activities against multi-drug resistant leukemia cells.

[Construction and expression of human 4-1BBL/anti-CD20 fusion protein].

AIM: To construct and express human 4-1BBL/anti-CD20 bispecific fusion protein and identify its biological activity. METHODS: PCR and overlapping PCR were used to construct human 4-1BBL/anti-CD20 bispecific fusion protein. DNA sequencing was performed by the terminus of the fusion protein nucleotide.The product was purified by affinity chromatography and analyzed by Western blot and its antigen-binding activity was examined by FACS. RESULTS: The data of DNA sequence showed that human 4-1BBL/anti-CD20 bispecific fusion protein was correct. The fusion protein was recovered in high yield (up to 4 mg/L) after E-tag purification and predominantly(90%) as a dimer. The fusion protein could bind to Raji cells(CD20(+)) and A549 cells(4-1BB(+)), respectively. CONCLUSION: The human 4-1BBL/anti-CD20 bispecific fusion protein with high level expression was successfully obtained and could bind to Raji ceIls and A549 cells.