Biomedical subjects

C Qian

Publications and source records attributed to C Qian.

At least 19 recordsLinked to original sources

PubMed2006

The antitumor activity of TRAIL and IL-24 with replicating oncolytic adenovirus in colorectal cancer.

Melanoma differentiation associated gene-7 (Mda-7)/IL-24 was previously cloned into ZD55 (an adenovirus with E1B55 deleted) to form ZD55-IL-24, which had much better antitumor effect than Ad-IL-24. According to its good antitumor properties, ZD55-IL-24 has been used in preclinical studies. But ZD55-IL-24 alone still could not completely eradicate established tumors in all nude mice. It was reported that IL-24 could induce and enhance the activity of tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) (a member of tumor necrosis factor (TNF) superfamily). Accordingly, the combined use of ZD55-IL-24 and ZD55-TRAIL was carried out in this study. Treatment with both ZD55-IL-24 and ZD55-TRAIL could induce more significant apoptosis in cancer cells in vitro compared with ZD55-IL-24 or ZD55-TRAIL alone. The combination of the two replicative adenoviruses had better antitumor activity in vivo than that of single oncolytic adenovirus and led to complete eradication of xenograft tumors in all treated mice. Upregulation of TRAIL was observed in tumor cells infected with ZD55-IL-24 and studies of the apoptotic cascade regulators indicate that ZD55-IL-24 could further enhance the activation of apoptosis through the TNF family of death receptors. We demonstrated for the first time the potential therapeutic effect of combined ZD55-IL-24 with ZD55-TRAIL for the targeted therapy of cancer.

Adenoviridae↗

PubMed2006

Increased VEGF levels induced by anti-VEGF treatment are independent of tumor burden in colorectal carcinomas in mice.

Inhibition of vascular endothelial growth factor (VEGF) by gene transfer techniques was effectively applied to control experimental tumor growth, whereas effects on systemic VEGF levels had not been investigated. Therefore, we evaluated the effect of VEGF inhibition by adenoviral-mediated gene delivery of a dominant-negative soluble fragment of FLK-1 (sFlk-1) on systemic VEGF levels, organ-specific VEGF-RNA expression and antitumor efficacy in a murine colorectal cancer (CRC) tumor model. Vector function of AdsFlk-1 was shown by Western blot analysis and transgene expression was documented over a time period of 42 days in the serum of treated mice. Although cell supernatant of CT26 cells contained considerable levels of VEGF, systemic VEGF levels in the serum of tumor-bearing mice remained unaffected. Interestingly, mice that were systemically treated with AdsFlk-1 showed a strong upraise of circulating VEGF, whereas VEGF remained at background levels in the control. Vascular endothelial growth factor was increased not only in tumor bearing but also in healthy, tumor-free mice. Vascular endothelial growth factor determination in liver tissue homogenates showed a 16.5-fold upraise in AdsFlk-1-treated animals as compared to the AdLacZ control. Consecutively, systemic small interfering RNA injection targeted against VEGF reverted elevated VEGF levels almost back to normal levels. In spite of elevated VEGF levels, AdsFlk-1 administration showed significant antitumor effects in a subcutaneous metastatic CRC tumor model. There was no significant correlation between antitumour treatment response and VEGF levels in this model. Collectively, we conclude that the systemic administration of AdsFlk-1 had significant inhibitory effects on metastatic CRC tumor growth in spite of elevated systemic VEGF levels and that VEGF serum concentrations did not correlate to tumor burden and antitumor treatment response in this model.

Adenoviridae↗

PubMed2006

SET domain protein lysine methyltransferases: Structure, specificity and catalysis.

Site- and state-specific lysine methylation of histones is catalyzed by a family of proteins that contain the evolutionarily conserved SET domain and plays a fundamental role in epigenetic regulation of gene activation and silencing in all eukaryotes. The recently determined three-dimensional structures of the SET domains from chromosomal proteins reveal that the core SET domain structure contains a two-domain architecture, consisting of a conserved anti-parallel beta-barrel and a structurally variable insert that surround a unusual knot-like structure that comprises the enzyme active site. These structures of the SET domains, either in the free state or when bound to cofactor S-adenosyl-L-homocysteine and/or histone peptide, mimicking an enzyme/cofactor/substrate complex, further yield the structural insights into the molecular basis of the substrate specificity, methylation multiplicity and the catalytic mechanism of histone lysine methylation.

Amino Acid Sequence↗

PubMed2005

An oncolytic adenovirus controlled by a modified telomerase promoter is attenuated in telomerase-negative cells, but shows reduced activity in cancer cells.

The promoter for human telomerase reverse transcriptase (hTERTp) is preferentially active in malignant cells. It was recently used to control the expression of the adenoviral E1A gene for the development of oncolytic adenoviruses. To ensure maximal repression in normal cells, the inclusion of additional E-boxes in the proximal region of the core promoter was described. We found that the transcriptional activity of this artificial sequence (T-255-4DEB) is minimal in normal cells, but it is also reduced in all the cancer cell lines tested. The cancer specificity of a new oncolytic adenovirus based in this promoter (AdTE1) was evaluated by direct comparison with wild-type adenovirus type 5 (AdWT) in vitro and in vivo. In all the parameters tested, AdTE1 was attenuated in normal cells, but the efficacy in cancer cells showed a parallel reduction, suggesting a lack of specificity. However, the cytotoxicity of AdTE1 was repressed in senescent cells compared to AdWT. Therefore, we conclude that AdTE1 is preferentially attenuated only in cells that are permanently devoid of telomerase expression such as senescent cells. Further modifications in the telomerase-based promoters should be introduced in order to combine maximal attenuation of oncolytic adenoviruses in normal tissues and enhanced activity in tumors.

Adenoviridae↗

PubMed2004

Treatment of colorectal and hepatocellular carcinomas by adenoviral mediated gene transfer of endostatin and angiostatin-like molecule in mice.

AIM AND METHOD: In this study, we explored the responsiveness of different tumour entities (colorectal carcinoma (CRC), hepatocellular carcinoma (HCC), and the murine Lewis lung carcinoma (LLC)) to angiostatic antitumour treatment with two recombinant adenoviral vectors encoding angiostatin-like molecule (AdK1-3) and endostatin (Adendo). RESULTS: AdK1-3 and Adendo exerted inhibitory biological functions on endothelial cell proliferation, migration, and tube formation in vitro. AdK1-3 inhibited significantly endothelial cell infiltration in vascular endothelial growth factor embedded Matrigel plugs in mice whereas Adendo showed only minor effects. Both AdK1-3 and Adendo induced similar antitumour effects in the LLC tumour model in immune competent C57BL/6 mice but AdK1-3 had stronger inhibitory effects in athymic mice. Furthermore, AdK1-3 inhibited tumour growth in a murine CRC and human HCC model but was ineffective in a human CRC model. In contrast, Adendo did not reduce tumour progress in either of these tumour models although AdK1-3 and Adendo effectively reduced intratumoral microvessel density in LLC tumours. CONCLUSION: Our data demonstrate that angiostatic gene therapy may form a feasible strategy for the treatment of established hepatocellular carcinomas and that in vivo antitumour efficacy of angiostatic proteins is tumour specific.

Adenoviridae↗

PubMed2003

Pancreatic cancer escape variants that evade immunogene therapy through loss of sensitivity to IFNgamma-induced apoptosis.

Combined injections into experimental tumor nodules of adenovirus encoding IL-12 and certain chemokines are capable to induce immune-mediated complete regressions. In this study, we found that the combination of two adenoviruses, one encoding IL-12 and other MIP3alpha (AdCMVIL-12+AdCMVMIP3alpha) was very successful in treating CT-26-derived colon carcinomas. However, in experimental tumors generated from the pancreatic carcinoma cell line Panc02 such combined treatment induces 50% of macroscopic complete regressions, although local relapses within 1 week are almost constant. We derived cell lines from such relapsing tumors and found that experimental malignancies derived from their inoculum were not amenable to treatment in any case with AdCMVIL-12+AdCMVMIP-3alpha. Importantly, relapsing cell lines were insensitive to in vitro induction of apoptosis by IFNgamma, in clear contrast with the original Panc02 cells. Comparative analyses by cDNA arrays of relapsing cell lines versus wild-type Panc02 were performed revealing an important number of genes (383) whose expression levels were modified more than two-fold. These changes grouped in certain gene ontology categories should harbor the mechanistic explanations of the acquired selective resistance to IFNgamma.

Adenoviridae↗

PubMed2003

The promise of gene therapy in gastrointestinal and liver diseases.

Gene therapy consists of the transfer of genetic material to cells to achieve a therapeutic goal. In the field of gastroenterology and hepatology gene therapy has produced considerable expectation as a potential tool in the management of conditions that lack effective therapy including non-resectable neoplasms of the liver, pancreas and gastrointestinal tract, chronic viral hepatitis unresponsive to interferon therapy, liver cirrhosis, and inflammatory bowel disease.

Animals↗

PubMed2002

A novel strategy for the generation of angiostatic kringle regions from a precursor derived from plasminogen.

In this study we have explored the feasibility of generating angiostatin by incorporating an endoproteolytic furin cleavage site into plasminogen to allow conversion of the precursor molecule into an angiostatic active K1-3 fragment. We show that secretable angiostatin can be successfully generated from cells infected with adenovirus carrying the furin-mutated plasminogen (AdmuthPlgK3). Supernatant from cells transduced with AdmuthPlagK3 inhibits tube formation and proliferation and migration of human umbilical vein endothelial cells with an efficiency similar to that of supernatant from cells infected with adenovirus expressing kringle 1-3 of plasminogen (AdK1-3). Administration of AdmuthPlgK3 and AdK1-3 in mice results in significantly decreased endothelial cell infiltration in VEGF-embedded Matrigel plugs. Treatment with AdmuthPlgK3 and AdK1-3 exerts strong antitumoral effect in models of hepatocellular carcinoma and Lewis lung cancer. This antitumor effect was associated with decreased microvessel density in the tumors. Taken together, our data demonstrate that angiostatin endowed with strong antiangiogenic and antitumor effects can be released from a furin-mutated plasminogen acting as a precursor. This strategy may have potential to develop angiostatic anti-cancer therapies.

Adenoviridae↗

PubMed2002

Gene therapy for liver diseases: recent strategies for treatment of viral hepatitis and liver malignancies.

Gene therapy has emerged as a powerful and very plastic tool to regulate biological functions in diseased tissues with application in virtually all medical fields. An increasing number of experimental and clinical studies underline the importance of genes as curative agents in the future. However, intense research is needed to evaluate the potential of gene therapy to improve efficacy and minimise the toxicity of the procedure.

Clinical Trials, Phase I as Topic↗

PubMed2002

Cytokine gene transfer into dendritic cells for cancer treatment.

Bone marrow-derived dendritic cells have been used to treat established experimental tumors by unleashing a cellular immune response against tumor antigens. Such antigens are artificially loaded onto dendritic cells' antigen-presenting molecules by different techniques including incubation with synthetic antigenic determinants, tumor lysates or nucleic acids encoding for those relevant antigens. Ex vivo gene transfer with viral and non-viral vectors is frequently used to obtain expression of the tumor antigens and thereby to formulate the therapeutic vaccines. Efficacy of the approaches is greatly enhanced if dendritic cells are transfected with a number of genes which encode immunostimulating factors. In some cases, such as with IL-12, IL-7 and CD40L genes, injection inside experimental malignancies of thus transfected dendritic cells induces complete tumor regression in several models. In this case tumor antigens are captured by dendritic cells by still unclear mechanisms and transported to lymphoid organs where productive antigen presentation to T-cells takes place. Many clinical trials testing dendritic cell-based vaccines against cancer are in progress and partial clinical efficacy has been already proved. Transfection of genes further strengthening the immunogenicity of such strategies will join the clinical club soon.

Bone Marrow Cells↗

PubMed2001

Binding site elucidation of hydantoin-based antagonists of LFA-1 using multidisciplinary technologies: evidence for the allosteric inhibition of a protein--protein interaction.

The binding site on the lymphocyte function-associated antigen-1 (LFA-1) of a class of hydantoin-based antagonists of leukocyte cell adhesion has been identified. This site resides in the inserted-domain (I-domain) of the CD11a chain at a location that is distal to residues known to be required for interactions with the intercellular adhesion molecules. This finding supports the hypothesis that the molecules are antagonizing cell adhesion via an allosteric modification of LFA-1. The binding site was identified using an integrated immunochemical, chemical, and molecular modeling approach. Antibodies that map to epitopes on the I-domain were blocked from binding to the purified protein by the hydantoins, indicating that the hydantoin-binding site resides on the I-domain. Photoaffinity labeling of the I-domain followed by LC/MS and LC/MS/MS analysis of the enzymatic digest identified proline 281 as the primary amino acid residue covalently attached to the photoprobe. Distance constraints derived from this study coupled with known SAR considerations allowed for the construction of a molecular model of the I-domain/inhibitor complex. The atomic details of the protein/antagonist interaction were accurately predicted by this model, as subsequently confirmed by the X-ray crystal structure of the complex.

Allosteric Site↗

PubMed2001

Alpha(v)beta(3) integrin-mediated adenoviral transfer of interleukin-12 at the periphery of hepatic colon cancer metastases induces VCAM-1 expression and T-cell recruitment.

We previously reported that systemic injection of recombinant adenovirus resulted in a rim of gene transduction around experimental liver tumor nodules. This zone of higher infection is dependent on the alpha(v)beta(3) integrin, acting as an adenovirus internalization receptor, which is overexpressed in tissues surrounding liver metastases. When a recombinant adenovirus encoding interleukin-12 (AdCMVIL-12) is given into a subcutaneous tumor nodule in mice also bearing concomitant liver tumors, a fraction of AdCMVIL-12 reaches the systemic circulation and infects liver tissue, especially at the malignant/healthy tissue interface. As a result of the expression at this location of the interleukin-12 transgenes, VCAM-1 is induced on vessel cells and mediates the recruitment of adoptively transferred anti-tumor cytolytic T-lymphocytes. These studies provide mechanistic explanations for the potent therapeutic synergy observed between interleukin-12 gene transfer and adoptive T-cell therapy.

Adenoviridae↗

PubMed2001

Anti-inflammatory activities of LDP-392, a dual PAF receptor antagonist and 5-lipoxygenase inhibitor.

Leukotrienes (LTs) and platelet-activating factor (PAF) are important mediators of inflammation and allergy. LDP-392, a novel dual PAF receptor antagonist and 5-lipoxygenase (5-LO) inhibitor, has been identified. LDP-392 is 17.9-fold more potent than zileuton (5-LO inhibitor) in the RBL cytosolic 5-LO assay, and equally potent as MK 287 (PAF receptor antagonist) in the human platelet PAF receptor binding assay. The in vivo dual activities of LDP-392 were confirmed by measuring the inhibition of ex vivo LTB(4)production in rats and PAF-induced hemoconcentration in mice. Intravenous administration of LDP-392 demonstrated greater inhibition than zileuton, BN 50739 or MK 287 on arachidonic acid-induced ear edema and protected mice from LPS-induced lethality. Topical administration of LDP-392, in a dose-dependent manner, inhibited TPA-induced ear edema in mice and UVB-induced erythema in guinea-pigs. These data suggest that LDP-392, as a dual PAF receptor antagonist and 5-LO inhibitor, may be of greater clinical effectiveness.

Animals↗

PubMed2001

IL-12 gene therapy for cancer: in synergy with other immunotherapies.

In preclinical models of cancer, gene therapy with interleukin 12 (IL-12) has reached unprecedented levels of success when combined with immunotherapy approaches such as gene transfer of other cytokines and/or chemokines, costimulatory molecules or adoptive cell therapy. These combinations have been found to produce synergistic rather than additive effects. Meanwhile, IL-12 gene therapy is beginning clinical testing as a single agent, but combination strategies are at hand.

4-1BB Ligand↗

PubMed2001

Development of an enzyme-linked immunosorbent assay for the determination of maduramicin in broiler chicken tissues.

Maduramicin is one of the most widely used coccidiostats in the world. A rapid and accurate analytical method for this drug should provide producers and users with an effective management tool. The current chromatographic methods are sensitive but labor-intensive. This paper reports the development of an enzyme-linked immunosorbent assay (ELISA) based on an immunoaffinity chromatography cleanup procedure for the analysis of maduramicin in broiler chicken tissues (including muscle, liver, and fat). Recoveries from fortified tissue homogenates at levels of 30.0-120.0 microg kg(-)(1) ranged from 76.4 to 107.5% with coefficients of variation of 3.8-16.4%. The limits of detection were 1.0 ng g(-)(1) in muscle, 2.8 ng g(-)(1) in liver, and 1.5 ng g(-)(1) in fat. The ELISA results from the analysis of incurred residue in tissue samples showed the cleanup procedure is viable.

Adipose Tissue↗

PubMed2001

Genetic heterogeneity in the toxicity to systemic adenoviral gene transfer of interleukin-12.

Despite the efficacy of IL-12 in cancer experimental models, clinical trials with systemic recombinant IL-12 showed unacceptable toxicity related to endogenous IFNgamma production. We report that systemic administration of a recombinant adenovirus encoding IL-12 (AdCMVmIL-12) has a dramatically different survival outcome in a number of mouse pure strains over a wide range of doses. For instance at 2.5 x 10(9) p.f.u., systemic AdCMVmIL-12 killed all C57BL/6 mice but spared all BALB/c mice. Much higher IFNgamma concentrations in serum samples of C57BL/6 than in those from identically treated BALB/c were found. Causes for heterogeneous toxicity can be traced to differences among murine strains in the levels of gene transduction achieved in the liver, as assessed with adenovirus coding for reporter genes. In accordance, IL-12 serum concentrations are higher in susceptible mice. In addition, sera from C57BL/6 mice treated with AdCMVmIL-12 showed higher levels of IL-18, a well-known IFNgamma inducer. Interestingly, lethal toxicity in C57BL/6 mice was abolished by administration of blocking anti-IFNgamma mAbs and also by simultaneous depletion of T cells, NK cells, and macrophages. These observations together with the great dispersion of IFNgamma produced by human PBMCs upon in vitro stimulation with IL-12, or infection with recombinant adenovirus encoding IL-12, suggest that patients might also show heterogeneous degrees of toxicity in response to IL-12 gene transfer.

Adenoviridae↗

PubMed2001

Gene therapy of orthotopic hepatocellular carcinoma in rats using adenovirus coding for interleukin 12.

The use of gene therapy to enhance antitumor immunity has emerged as a promising procedure to fight cancer. In this study we have tested the ability of an adenovirus carrying interleukin 12 (IL-12) gene (AdCMVIL-12) to eliminate tumoral lesions in 3 animal models of orthotopic hepatocellular carcinoma (HCC). Intratumoral injection of AdCMVIL-12 in animals with a single big tumor nodule implanted in the liver resulted in significant inhibition of tumor growth in a dose-dependent manner. Fifty percent of animals that received a dose of 5 x 10(9) plaque-forming units, showed complete regression of the tumor 2 weeks after treatment. In animals with 2 independent tumor nodules in the left liver lobe, injection in only one of them of 5 x 10(9) pfu AdCMVIL-12 induced, 15 days after therapy, complete regression of 50% of treated tumors and also of 50% of untreated lesions, with 60% long-term survival. Rats that were tumor free after therapy with AdCMVIL-12 showed protection against tumor rechallenge. A group of rats received the carcinogen diethylnitrosamine and developed multiple hepatic dysplasic nodules of 1 to 5 mm in diameter. These animals were treated by intrahepatic artery injection of either AdCMVIL-12 (5 x 10(9) pfu) or control vector. In this model AdCMVIL-12 induced complete tumor regression in 20% of treated rats and inhibited tumor growth in 60% of cases with an increase in rat survival. Activation of natural killer (NK) cells and inhibition of angiogenesis were found to be antitumor mechanisms set in motion by AdCMVIL-12. Our data indicate that experimental HCC can be efficiently treated by intratumoral or intravascular injection of adenovirus expressing IL-12.

Adenoviridae↗

PubMed2001

Adenovirus-mediated CD40 ligand gene therapy in a rat model of orthotopic hepatocellular carcinoma.

Unresectable hepatocellular carcinoma (HCC) lacks effective therapy and entails very poor prognosis. In this study, we have explored a gene-therapeutic approach to stimulate antitumor immunity by adenoviral-mediated transfer of CD40 ligand to treat HCC in rats. In vitro infection of a rat HCC cell line (McA-RH7777) with adenoviral vector expressing CD40 ligand (AdCMVmCD40L) induced CD40L expression in a dose-dependent manner. Expression of CD40L in McA-RH7777 cells did not alter their growth rate in vitro, but it abrogated their tumorigenicity when CD40L-expressing cells were implanted into the liver of syngenic Buffalo rats. In vivo gene therapy of established orthotopic HCC nodules (6.5 mm in diameter) in Buffalo rats by intratumor injection of AdCMVmCD40L vector led to complete tumor eradication and long-term survival in 69.5% of treated animals. Therapy with AdCMVmCD40L induced strong lymphocytic infiltration of the tumoral tissue and increased apoptosis of malignant cells. The observed antitumoral effect was mediated by CD8(+) T cells and was associated with increased interleukin (IL)-12 serum levels and enhanced natural killer (NK) activity. Animals that eliminated the tumor after in vivo gene therapy developed protective antitumor immunity being resistant to rechallenge with neoplastic cells. Toxicity of the therapy with AdCMVmCD40L was slight, with only a transient increase in the level of serum transaminases and minor lymphocyte infiltration of normal liver tissue. These data demonstrate that intratumoral administration of AdCMVmCD40L may provide an efficient and safe treatment for HCC.

Adenoviridae↗