Biomedical subjects

Yu-quan Wei

Publications and source records attributed to Yu-quan Wei.

At least 19 recordsLinked to original sources

PubMed2006

Prophylaxis against carcinogenesis in three kinds of unestablished tumor models via IL12-gene-engineered MSCs.

Mesenchymal stem cells (MSCs) were adenovirally engineered to secrete interleukin-12 (AdIL-12-MSCs) and evaluated for their anticarcinogenesis efficacy against three kinds of unestablished tumor models including B16 melanoma, LLC Lewis lung cancer and HCC hepatoma. Injection of AdIL-12-MSCs into protected mice before tumor inoculation prevented all of 12 mice in B16 preventive groups, 10 out of 12 in LLC lung cancer model and 11 out of 12 mice in HCC hepatoma model from developing tumors, whereas the control groups pre-receiving PBS were validated for 100% carcinogenesis; the tumor formation rates in free-AdIL-12 and vacant MSC groups were unveiled between approximately 83 and 100% even with plentiful angiogenesis and newborn lymphatic vessels, as well as distant metastases. As a novel approach, AdIL-12-MSC has revealed expected preventive effects on carcinogenesis (P<0.01) with low-toxic, broad-spectrum and long-range superiorities. In conclusion, our data indicate that AdIL-12-MSC possess the potential for tropism to preclinical tumor lesions and deprives surviving or hibernating tumor cells, which have escaped from conventional treatments, of revival and recurrence.

Animals↗

PubMed2006

Liposomal quercetin efficiently suppresses growth of solid tumors in murine models.

PURPOSE: Quercetin is a potent chemotherapeutic drug. Clinical trials exploring different schedules of administration of quercetin have been hampered by its extreme water insolubility. To overcome this limitation, this study is aimed to develop liposomal quercetin and investigate its distribution in vivo and antitumor efficacy in vivo and in vitro. EXPERIMENTAL DESIGN: Quercetin was encapsulated in polyethylene glycol 4000 liposomes. Biodistribution of liposomal quercetin i.v. at 50 mg/kg in tumor-bearing mice was detected by high-performance liquid chromatography. Induction of apoptosis by liposomal quercetin in vitro was tested. The antitumor activity of liposomal quercetin was evaluated in the immunocompetent C57BL/6N mice bearing LL/2 Lewis lung cancer and in BALB/c mice bearing CT26 colon adenocarcinoma and H22 hepatoma. Tumor volume and survival time were observed. The mechanisms underlying the antitumor effect of quercetin in vivo was investigated by detecting the microvessel density, apoptosis, and heat shock protein 70 expression in tumor tissues. RESULTS: Liposomal quercetin could be dissolved in i.v. injection and effectively accumulate in tumor tissues. The half-time of liposomal quercetin was 2 hours in plasma. The liposomal quercetin induced apoptosis in vitro and significantly inhibited tumor growth in vivo in a dose-dependent manner. The optimal dose of liposomal quercetin resulted in a 40-day survival rate of 40%. Quantitative real-time PCR showed that liposomal quercetin down-regulated the expression of heat shock protein 70 in tumor tissues. Immunohistochemistry analysis showed that liposomal quercetin inhibited tumor angiogenesis as assessed by CD31 and induced tumor cell apoptosis. CONCLUSIONS: Our data indicated that pegylated liposomal quercetin can significantly improve the solubility and bioavailability of quercetin and can be a potential application in the treatment of tumor.

Adenocarcinoma↗

PubMed2006

Different attitudes of oncology clinicians toward truth telling of different stages of cancer.

OBJECTIVES: To investigate different attitudes of oncology clinicians toward whether and how to disclose diagnosis to patients with different stages of cancer. MATERIALS AND METHODS: A questionnaire investigating physician's demographic information and attitude toward truth telling was delivered to 256 Chinese oncology clinicians. RESULTS: Two hundred thirty-two (90.6%) physicians completed the questionnaire. Of these oncology clinicians, 87.5% reported that a patient with early-stage cancer should be informed of the diagnosis, while only 40.5% believed that a patient with terminal illness should know the truth (P<0.001). Physicians who preferred to tell the truth reported that patients with early or terminal stage of cancer should be informed by the doctor-in-charge (81.3 vs 77.7%, respectively; P>0.05), immediately after the diagnosis (83.7 vs 87.2%, respectively), and in a quiet and undisturbed room (63.5 vs 68.1%, respectively; P>0.05). In stepwise multiple logistic regression analyses, no demographic information showed association with truth telling of early-stage cancer. Women doctors [odds ratio (OR), 2.25; 95% CI, 1.31 to 3.89; P=0.004] were more likely than men to want the patient to be informed of the terminal illness. Physicians with cancer relatives (OR, 0.55; 95% CI, 0.31 to 0.97; P=0.04) were less likely than physicians without cancer relatives to want the patient to be informed of the terminal illness. CONCLUSION: Oncology clinicians differed in their attitudes toward truth telling of different stages of cancer. Physicians reported that the doctor-in-charge should be the ones to disclose the condition of the patient, immediately after the diagnosis, and in a quiet and undisturbed room.

Adult↗

PubMed2006

[The regulating roles of angiopoietins/TEK-2 in angiogenesis].

Angiopoietins(ANGPT) and their endothelial cell-specific tyrosine kinase receptors TEK are the major regulators of blood vessels angiogenesis under physiological and pathologic conditions. ANGPT1 is essentially involved in maturation, stabilization, and remodeling of blood vessels through inducing TEK autophosphorylation, promoting endothelial cell migration and survival. Instead, ANGPT2 appears to act as a natural antagonist of ANGPT1, it can activate vascular remodeling with the presence of vascular endothelial growth factor(VEGF) or regress frank blood vessels under the absence of VEGF. High expression of angiopoietins and TEK is often detected in tumor tissues. Many studies showed that disrupting the ANGPT/TEK receptor pathway could inhibit the growth of a number of murine tumors and human tumors. Thus, it is possible that inhibitors targeting the ANGPT/TEK pathway will have broad clinical utility to treatment of cancer.

Angiopoietin-1↗

PubMed2006

Expression of extracellular domain of human vascular endothelial growth factor receptor-2 in Pichia pastoris.

OBJECTIVE: To investigate the feasibility of high expressing extracellular domain of human vascular endothelial growth factor receptor-2 (heVEGFR-2) with eukaryotic protein structure in Pichia pastoris. METHODS: We used PCR to amplify the DNA fragment encoding heVEGFR-2 from pORF-heVEGFR-2. The recombinant Pichia pastoris secretory expression vector(pPICZalphaA-heVEGFR-2)was constructed and transferred into Pichia pastoris X-33 by electroporation. The high expression transformnants were identified through its drug-resistant phenotype and methanol induction. RESULTS: As indicated by SDS-PAGE, the recombinant heVEGFR-2 protein with a molecular weight (MW) approximately 108 kDa, which reached 80 mg/L in the mass concentration, comprised 45% of the total expressed secreted proteins from Pichia pastoris X-33. The section of heVEGFR-2 had a MW approximately 106 kDa. The results of western blot analysis demonstrated that this protein could be specifically recognized by the rat monoclonal antibody against mouse VEGFR-2 (rat McAb against mVEGFR-2). CONCLUSION: The heVEGFR-2 with eukaryotic protein structure can get a high expression in Pichia pastoris.

Animals↗

PubMed2006

[Proteomic analysis of proteins related to retinoid acid resistance].

OBJECTIVE: To evaluate the applicability of proteomic methods for shedding light on the mechanisms of All-trans retinoic acid resistance. METHODS: The expression of cellular proteins in the retinoid acid sensitive cell line NB4 and retinoid acid resistant cell line MR2 was analyzed using the two-dimensional polyacrylamide gel electrophoresis (2D-PAGE). Differentially expressed proteins were analyzed by mass spectrometry for peptide mass finger and identified by SWISS-PROT protein database. RESULTS: Approximately 600 spots appeared in an sodium dod(SDS-GEL). The match of the expression of cellular proteins between NB4 and MR2 was better. Three significantly differentially expressed proteins were screened and identified to DJ-1 and HSP70, as well as KIAA1289 of which the function is not yet known. CONCLUSION: The utilization of 2D-PAGE, coupled with mass spectrometry is effective in screening the drug resistance-associated proteins and could provide molecular targets for the elucidation of resistance mechanisms.

Antineoplastic Agents↗

PubMed2006

[Construction of mammalian co-expression plasmid pIRES -LMP1-HSP90 beta and its expression in vitro].

OBJECTIVE: This study sought to clone Epstein-Barr virus latent membrane protein 1 (LMP1) and heat shock protein 90 beta (HSP90 beta) of nasopharyngeal carcinoma (NPC), to construct the mammalian co-expression plasmid pIRES-LMP1-HSP90 beta, and to detect the expression of the plasmid in vitro. METHODS: Total RNA was isolated from human NPC by cloning technique, their cDNA fragments of LMP1 gene and HSP90 beta gene were gained by RT-PCR, and their cDNA fragments were constructed into the mammalian co-expression plasmid vector pIRES. The inserted target genes in the mammalian co-expression plasmid were verified by nucleotide sequencing. COS cell line was transfected with this mammalian co-expression plasmid using lipofectin reagent. The expression of LMP1 and HSP90 beta molecules were detected by RT-PCR and Western blot technique. RESULTS: The mammalian expression plasmid pIRES-LMP1-HSP90 beta was obtained by cloning technique. The nucleotide sequences of LMP1 gene and HSP90 beta gene in this mammalian co-expression plasmid had high homology with EBV-LMP1 (100%) and human HSP90 beta (100%) respectively. After transfection with this mammalian co-expression plasmid, the LMP1 and HSP90 beta molecules were expressed in COS cells. CONCLUSION: The constructed mammalian co-expression plasmid pIRES-LMP1-HSP90 beta can express LMP1 and HSP90 beta molecules in vitro at the same time.

Animals↗

PubMed2006

[Experimental study of anti-cancer effect of Mannan-modified targeted nanoliposome on mice].

OBJECTIVE: To test the anti-cancer effect of mannan-modified targeted nanoliposome on mice. METHODS: The 3beta[N-(N',N'-dimethylaminoethane) -carbamoyl] cholesterol (DC-chol) was synthesized by the chemical reaction of cholesteryl chloroformate and N, N-dimethylethylendiamine. The DC-chol was then mixed with dioleoylphosphatidylethanolamine (DOPE) and chol-AECM-mannan to produce the sonicated mannan-modified targeted nanoliposome. The size of the nanoliposome was measured by zetasizer. Nanoliposome or purified EGFR (as control) was injected to the C57 mice with implanted lung cancers intravenously. The growth of tumors was observed, followed by ELISA and Western tests of serum antibodies. RESULTS: The liposome nanoparticle had a size of 132 nm. The experimental groups had significant higher levels of blood serum antibodies than the controls. The experimental groups also had less volumes of tumors than the controls (P<0.05). CONCLUSION: The growth of tumor has been inhibited by mannan-modified targeted nanoliposome. The mannan-modified targeted nanoliposome has anti-cancer effect on mice.

Animals↗

PubMed2006

[Expression and characterization of mouse 17-1A antigen from Pichia pastoris].

OBJECTIVE: This is a ground work in preparation for the development of a vaccine against tumor, in which 17-1A glucoprotein, a tumor associated antigen (TAA), was cloned and expressed in Pichia pastoris. METHODS: The cDNA of 17-1A gene was cloned from nephridial tissue of mouse embryo by RT-PCR and subsequently inserted into pPICZaA plasmid after digestion with Xho I and Xba I. The linearized recombinant plasmid was transformed into Pichia pastoris strain GS115. 17-1A glucoproteins were secreted into culture supernatant through alpha-signal peptide of AOX I after inducation with methanol. The protein products were analyzed and characterized by SDS-PAGE and Western-blot. RESULTS: The plasmid pPICZalphaA-17-1A was constructed and verified by sequenceing. 17-1A glucoproteins were expressed stably and glycosylated in Pichia pastoris. CONCLUSION: Glycosylated tumor associated antigen 17-1A can be expressed in Pichia pastoris.

Animals↗

PubMed2006

[Anti-tumor effects of recombinant adenovirus encoding survivin encapsulated in cationic liposome].

OBJECTIVE: To explore the anti-tumor effects and mechanisms of recombinant adenovirus encoding survivin encapsulated in cationic liposome. METHODS: CT26 tumor model was established in BALB/c mice. Fifty mice were randomly divided into five groups, including the group treated with recombinant adenovirus encoding survivin encapsulated in cationic liposome (Lip+ Ad-sur), the group of recombinant adenovirus encoding survivin (Ad-sur), the group of recombinant adenovirus encoding null encapsulated in cationic liposome (Lip+Ad-null), the group of liposome (Lip), and the group of PBS alone (PBS). Survival rate of mice, tumor volume, and side effects of treatments were observed. Lymphocytes were activated by adenovirus vaccine to kill tumor cells in vitro and in vivo. CTL assay and histological examination were carried out. RESULTS: Immunotherapy with recombinant adenovirus encoding survivin encapsulated in cationic liposome was effective for inducing protective and therapeutic anti-tumor immunity in CT26 tumor model. In the combination therapy group, the tumor growth was inhibited and the tumor volume was significantly smaller when compared with the controls. The survival rate of mice in the combination therapy group at 7 weeks after inoculation of tumor cells was significantly higher than that of the control group. Histologically, the tumor tissue was markedly necrotic and was infiltrated by lymphocytes. 51Cr assay in vitro indicated that the combination therapy group showed higher specific killing activity against CT26 tumor cells than did the control groups, and the T cells were independent of NK cells. CONCLUSION: Immunotherapy with recombinant adenovirus encoding survivin encapsulated in cationic liposome was noted to have a significant anti-tumor effect on CT26 tumor model.

Adenoviridae↗

PubMed2006

[An experimental research on the combination treatment of sFLK-1 gene therapy combined with gamma knife].

OBJECTIVE: To evaluate whether the sustained expression by adenovirus-mediated gene (sFLK-1) transfer can enhance the treatment efficacy of gamma knife radiosurgery. METHODS: The mouse sFLK-1 gene was cloned to construct the recombinant adenovirus. The gliomata growing in BALB/c female nude mice with an initial mean volume of (109.3 +/- 20.5) mm3 were treated with gamma knife alone (13 Gy on day 12), sFLK-1 adenovirus alone (1 x 10(9) plaque-forming units, PFU was given to two mouse tail vein by injections, 7 and 14 days), gamma knife associated with sFLK-1 adenovirus or control adenovirus (1 x 10(9) PFU was given to two mouse tail vein by injections, 13 and 17 days). After the completion of therapy, the tumor size was recorded. The microvessel density (MVD) and tumor apoptosis were evaluated by immunohistochemical means. RESULTS: As comparing with three other control groups, the combination treatment group with sFLK-1 gene therapy and gamma knife not only significantly reduced tumor volume and prolonged the life span of tumor burden mice as well. In addition, the average tumor weights were lower in sFLK-1 combined with gamma knife group than in any other control group. Immunohistochemical analysis of glioma demonstrated a decreased MVD and a high apoptosis cell rate in sFLK-1 combined with gamma knif group. CONCLUSION: The antitumor effect of gamma knife can be potentiated by sFLK-1 gene therapy. Thus the combination of sFLK-1 gene therapy and gamma knife results an additive effect of antitumor. The observation may provide an important strategy for treatment cancer metastasis.

Adenoviridae↗

PubMed2005

Human T lymphocyte responses against lung cancer induced by recombinant truncated mouse EGFR.

The induction of active cellular responses against EGFR should be a promising approach for the treatment of those receptor-positive tumors. However, the immunity against EGFR is presumably difficult to elicit by vaccine based on self or syngeneic EGFR due to the immune tolerance acquired during the development in immune system. We proposed a model to break immune tolerance against self-EGFR through an altered immunogen source based on xenogeneic homologous EGFR. We have previously shown human EGFR as a xenoantigen could induce specific immune responses in mouse and cross-react with mouse EGFR, and resulted in therapeutic benefits for EGFR-positive mouse tumor. Here, we show a recombinant form of extracellular domain of mouse EGFR, in the presence of DCs, could activate human peripheral T cells to proliferate, secret IFN-gamma, the induced responses could cross-react with human EGFR and kill autologous EGFR-positive lung cancer cells which could be blocked by anti-CD8 and anti-MHC class I antibody. There is no detectable cytotoxical activity against lung tissue, liver tissue and kidney tissue derived from paracancerous normal tissue. These observations suggest that antitumor immunity induced by the truncated mouse EGFR may be provoked in a cross-reaction between mouse EGFR and self-EGFR, and may provide insight into treatment of EGFR-positive tumors through induction of the autoimmune responses against EGFR.

Animals↗

PubMed2005

[Expression of xenogeneic homologous epidermal growth factor receptor ectodomain in Pichia pastoris].

OBJECTIVE: To develop a secreted expression system of xenogeneic homologous epidermal growth factor receptor (EGFR) ectodomain using Pichia pastoris (P. pastoris), thus providing a basis for subsequent antitumor immunological researches on EGFR subunit protein vaccine. METHODS: In order to construct the secreted expression vector pPICZaA-mer and pPICZaA-her, we recombined the cDNA of xenogeneic (human) EGFR ectodomain (her) and the corresponding control mouse EGFR ectodomain (mer) with the empty plasmid pPICZaA, respectively. Then the recombinant plasmids were linearized by Sac I and transformed into P. pastoris strain GS115 by electroporation. The positive transformants were selected on YPDS plate including Zeocin and were induced to express by methanol. Consequently, the proteins in the culture supernatant were assayed with SDS-PAGE and Western-blot. So we could choose the high-level secreted expression recombinant strain to produce protein vaccine vastly. RESULTS: We got the secreted expression of mouse and human EGFR ectodomain in P. pastoris. The relative molecular mass of the two aimed proteins is about 95 x 10(3). The Western-blot analysis demonstrated that the expression proteins have much good antigenicity and specificity. CONCLUSION: The recombinant plasmids pPICZaA-mer and pPICZaA-her could be induced to express the EGFR aimed proteins by methanol in methanol-trophic yeast expression system.

Animals↗

PubMed2005

Gemcitabine and cisplatin in advanced nasopharyngeal carcinoma: a pilot study.

A pilot study was performed to evaluate the efficacy and safety of gemcitabine and cisplatin combination in the treatment of patients with metastatic nasopharyngeal carcinoma (NPC). Eligible patients were those with metastatic NPC who had been treated with radiotherapy and cisplatin plus 5-fluorouracil chemotherapy. Cisplatin was given intravenously at the fixed dose of 30 mg/m2 on days 1-3. Gemcitabine was intravenously administered over 30 min infusion with the dose escalated from 800 to 1200 mg/m2 on days 1 and 8. The 3-week schedule defined a cycle of treatment. Fifteen patients were enrolled and assessed for the worst toxicities. For a total of 83 cycles, Grade 3-4 toxicity was 46.7 % for neutropenia, 40.0 % for thrombocytopenia, and 20.0% for anemia. Grade 3 nonhematologic toxicity was 13.3%. Fourteen patients were assessable for response. The overall response rate was 92.9%, with complete response in three patients (21.4%). Median survival was 10.2 months. Seven patients had lived more than one year, and two patients had lived more than 2 years. The recommended dose of gemcitabine was 1000 mg/m2 on days 1 and 8 in each cycle. In conclusion, the present combination is well tolerated and highly active in the treatment of advanced NPC patients.

Adult↗

PubMed2005

[Prokaryotic expression, purification and identification of recombinant Xenopus laevis and mouse vascular endothelial growth factors].

OBJECTIVE: To perform prokaryotic expression, purification and identification of Xenopus laevis and mouse vascular endothelial growth factors (VEGF). METHODS: The prokaryotic expression vectors were constructed by restriction endonuclease digestion and ligation, then the recombinant vector pET-xVEGF and the control vector pET-mVEGF were identified by restriction enzymatic digestion and DNA sequencing. The confirmed vectors were transformed into Escherichia coli. BL21 (DE3) and recombinant protein expression was induced by Isopropy-beta-D-thiogalactoside. The recombinant xVEGF and mVEGF were obtained and purified by Ni-NTA affinity chromatography under denature conditions and enterokinase specific digestion, respectively. Finally, the purified proteins' molecular weights and specificity were detected by SDS-PAGE and western blot analysis. RESULTS: Two new recombinant expression vectors, pET-xVEGF and pET-mVEGF, were constructed successfully. The xVEGF and mVEGF fusion proteins were expressed in E. coli. BL21 (DE3) stably, and the molecular weights of the purified xVEGF and mVEGF were identical to the expected values. The purity of final products reached a level higher than 95%. In addition, these two purified proteins could react with a specific antibody against mouse VEGF as expected. CONCLUSION: Recombinant Xenopus laevis VEGF and its control mouse VEGF protein may provide tools for further study of anti-tumor active immunity with this xenogeneic protein vaccine in mouse tumor models.

Animals↗

PubMed2005

[Effect of full-length cyclin B1 antisense cDNA on chemosensitivity of lewis lung carcinoma cells to gemicitabine in vitro and in vivo].

OBJECTIVE: To evaluate the effect of full-length cyclin B1 antisense cDNA (AS-CLB1) on chemosensitivity of Lewis lung carcinoma cells (LL/2) to gemicitabine (GEM) in vitro and in vivo and hence provide a therapeutic regiment for treating non-small cell lung (NSCL) cancer using AS-CLB1 combined with GEM. METHODS: Cell cycle phase distribution and apoptosis of LL/2 parent cells, LL/2/vect and LL/2/AS-CLB1 transfectants (LP, LV and LA cells) were determined by flow cytometry. In addition, the three kinds of cells were treated with GEM (20 nmol/L-20 micromol/L) in vitro for 1 h and 24 h respectively, and then cytotoxicity of GEM was measured by MTT assay. After inoculation with the three kinds of cells respectively, the C57BL/6 mice were treated with GEM [25 - 125 mg/(kg x day)] once every three days for four times when tumors developed; tumorigenicity and survival were observed and cell apoptosis in tumor tissues was determined by flow cytometry. RESULTS: LA cells displayed apparent apoptosis and G1 arrest compared with LP and LV cells (controls). Additionally, cytotoxicity of GEM to LA cells was more obvious than that to controls. Moreover, tumorigenicity was inhibited, cell apoptosis in tumor tissues was induced, and survival was evidently increased in LA cells group. CONCLUSION: AS-CLB1 slightly increased the sensitivity of LL/2 cells to GEM in vitro and in vivo. The function of AS-CLB1 may be associated with its ability to enhance the anti-tumor activity of GEM by inducing cell apoptosis and G1 arrest.

Animals↗

PubMed2005

[Construction of the recombinant adenovirus vector expressing human CD40 ligand gene].

OBJECTIVE: To construct a recombinant adenovirus vector expressing hCD40L gene and explore it in the use of anti-tumor gene therapy. METHODS: 1,900 bp gene fragment was obtained form plasmid pORF-hCD40L by Xho I/Swa I cutting and then cloned directionally into the pShuttle plasmid, finally, the resultant plasmid was digested by restriction endonnuclease PmeI and subsequently cotransformtion into BJ5183 cells with the adenoviral backbone pAdEasy-1 to obtain the homologous recombinant and then the recombinant was packaged in the 293 cells. Some methods such as PCR and endonulease digestion were employed to identify the recombinant adenovirus. RESULTS: The evidences of endonulease digestion and PCR analysis confirmed that recombinant hCD40L gene was correctly inserted into adenovirus vector. CONCLUSION: The adenoviral vector which expressed hCD40L gene was constructed. It provides an experimental basis for studies on it expression in the mammalian cells and in tumor gene therapy.

Adenoviridae↗

PubMed2004

[First-line Xeloda (Capecitabine) treatment for advanced and recurrent colorectal cancer].

OBJECTIVE: To evaluate the efficacy and safety of capecitabine as first-line therapy in patients with advanced and recurrent colorectal cancer. METHODS: From December 2000 to November 2001, sixty patients with advanced and recurrent colorectal cancer received first-line capecitabine treatment given at a dose of 1250 mg/m(2) twice daily, on days 1 - 14 every 21 days. At least 2 cycles were administered. RESULTS: The overall response rate was 23.3% with 14 PR, 24 SD (40.0%) and 15 PD. The median survival time was 14.7 months. The survival rate was 63.9% at 12-months and 33.4% at 24-months. Grade III-IV adverse effects were diarrhea in 4 patients (6.6%), anemia in 2 (3.3%) and hand-foot syndrome (HFS) in 1 (1.7%); Grade I-II adverse effects were hyperpigmentation in 20 (33.3%), HFS in 18 (30.0%) and diarrhea in 10 (16.7%). CONCLUSION: Capecitabine is an efficacious and better-tolerated alternative treatment for the patients with advanced and recurrent colorectal cancer.

Adult↗