Biomedical subjects

Mary Sproull

Publications and source records attributed to Mary Sproull.

13 recordsLinked to original sources

PubMed2006

Discovering clinical biomarkers of ionizing radiation exposure with serum proteomic analysis.

In this study, we sought to explore the merit of proteomic profiling strategies in patients with cancer before and during radiotherapy in an effort to discover clinical biomarkers of radiation exposure. Patients with a diagnosis of cancer provided informed consent for enrollment on a study permitting the collection of serum immediately before and during a course of radiation therapy. High-resolution surface-enhanced laser desorption and ionization-time of flight (SELDI-TOF) mass spectrometry (MS) was used to generate high-throughput proteomic profiles of unfractionated serum samples using an immobilized metal ion-affinity chromatography nickel-affinity chip surface. Resultant proteomic profiles were analyzed for unique biomarker signatures using supervised classification techniques. MS-based protein identification was then done on pooled sera in an effort to begin to identify specific protein fragments that are altered with radiation exposure. Sixty-eight patients with a wide range of diagnoses and radiation treatment plans provided serum samples both before and during ionizing radiation exposure. Computer-based analyses of the SELDI protein spectra could distinguish unexposed from radiation-exposed patient samples with 91% to 100% sensitivity and 97% to 100% specificity using various classifier models. The method also showed an ability to distinguish high from low dose-volume levels of exposure with a sensitivity of 83% to 100% and specificity of 91% to 100%. Using direct identity techniques of albumin-bound peptides, known to underpin the SELDI-TOF fingerprints, 23 protein fragments/peptides were uniquely detected in the radiation exposure group, including an interleukin-6 precursor protein. The composition of proteins in serum seems to change with ionizing radiation exposure. Proteomic analysis for the discovery of clinical biomarkers of radiation exposure warrants further study.

Biomarkers, Tumor↗

PubMed2005

Orthotopic growth of human glioma cells quantitatively and qualitatively influences radiation-induced changes in gene expression.

The effect of radiation on gene expression has been most frequently studied using tissue culture models. To determine the influence of experimental growth condition on radiation-induced changes in gene expression, microarray analysis was done on two human glioma cell lines (U87 and U251) grown in tissue culture and as s.c. or i.c. xenografts. Compared with tissue culture, the number of genes, whose expression was affected by radiation in both cell lines, was increased in the s.c. xenografts and further increased in the orthotopic tumors. Furthermore, in each growth condition, radiation modulated the expression of a different set of genes. In addition, whereas there were few commonly affected genes after irradiation of U87 and U251 in tissue culture, there were 729 common changes after orthotopic irradiation. These results indicate that the influence of the orthotopic environment on radiation-induced modulation of gene expression in glioma cells was both quantitative and qualitative. Moreover, they suggest that investigations of the functional consequence of radiation-induced gene expression will require accounting for experimental growth conditions.

Animals↗

PubMed2005

Influence of in vivo growth on human glioma cell line gene expression: convergent profiles under orthotopic conditions.

Defining the molecules that regulate tumor cell survival is an essential prerequisite for the development of targeted approaches to cancer treatment. Whereas many studies aimed at identifying such targets use human tumor cells grown in vitro or as s.c. xenografts, it is unclear whether such experimental models replicate the phenotype of the in situ tumor cell. To begin addressing this issue, we have used microarray analysis to define the gene expression profile of two human glioma cell lines (U251 and U87) when grown in vitro and in vivo as s.c. or as intracerebral (i.c.) xenografts. For each cell line, the gene expression profile generated from tissue culture was significantly different from that generated from the s.c. tumor, which was significantly different from those grown i.c. The disparity between the i.c gene expression profiles and those generated from s.c. xenografts suggests that whereas an in vivo growth environment modulates gene expression, orthotopic growth conditions induce a different set of modifications. In this study the U251 and U87 gene expression profiles generated under the three growth conditions were also compared. As expected, the profiles of the two glioma cell lines were significantly different when grown as monolayer cultures. However, the glioma cell lines had similar gene expression profiles when grown i.c. These results suggest that tumor cell gene expression, and thus phenotype, as defined in vitro is affected not only by in vivo growth but also by orthotopic growth, which may have implications regarding the identification of relevant targets for cancer therapy.

Animals↗

PubMed2005

Enhancement of in vitro and in vivo tumor cell radiosensitivity by valproic acid.

Valproic acid (VA) is a well-tolerated drug used to treat seizure disorders and has recently been shown to inhibit histone deacetylase (HDAC). Because HDAC modulates chromatin structure and gene expression, parameters considered to influence radioresponse, we investigated the effects of VA on the radiosensitivity of human brain tumor cells grown in vitro and in vivo. The human brain tumor cell lines SF539 and U251 were used in our study. Histone hyperacetylation served as an indicator of HDAC inhibition. The effects of VA on tumor cell radiosensitivity in vitro were assessed using a clonogenic survival assay and gammaH2AX expression was determined as a measure of radiation-induced DNA double strand breaks. The effect of VA on the in vivo radioresponse of brain tumor cells was evaluated according to tumor growth delay analysis carried out on U251 xenografts. Irradiation at the time of maximum VA-induced histone hyperacetylation resulted in significant increases in the radiosensitivity of both SF539 and U251 cells. The radiosensitization was accompanied by a prolonged expression of gammaH2AX. VA administration to mice resulted in a clearly detectable level of histone hyperacetylation in U251 xenografts. Irradiation of U251 tumors in mice treated with VA resulted in an increase in radiation-induced tumor growth delay. Valproic acid enhanced the radiosensitivity of both SF539 and U251 cell lines in vitro and U251 xenografts in vivo, which correlated with the induction of histone hyperacetylation. Moreover, the VA-mediated increase in radiation-induced cell killing seemed to involve the inhibition of DNA DSB repair.

Acetylation↗

PubMed2004

Evaluation of chelating agents as anti-angiogenic therapy through copper chelation.

The evaluation of several sets of polyamine donor chelating agents including a selection of novel hexadentate 1,3,5-cis,cis-triaminocyclohexane (tach) based derivatives were performed in an in vitro endothelial cell proliferation assay to assess their cytotoxicity and selectivity as novel anti-angiogenic agents. The selective nature of the anti-angiogenic agents for human umbilical vein endothelial cells (HUVEC) was compared to a normal fibroblast cell line and a human Glioma cell line to evaluate these compounds. Linear tri- and tetra-polyamines were superior to both macrocyclic and the tach based polyamine chelating agents in terms of selectivity of its inhibitory activity toward the proliferation of HUVEC cells compared to the fibroblast and human Glioma cells. The linear polyamine, triethylenetetramine (22), previously reported to possess anti-angiogenic properties failed to demonstrate any selectivity for inhibiting the proliferation of HUVEC cells compared to the fibroblast and human Glioma cells.

Angiogenesis Inhibitors↗

PubMed2004

Enhancement of xenograft tumor radiosensitivity by the histone deacetylase inhibitor MS-275 and correlation with histone hyperacetylation.

PURPOSE: Histone deacetylase (HDAC) inhibitors are undergoing clinical evaluation in cancer therapy. Because HDAC modulation has been shown to enhance the radiosensitivity of tumor cells in vitro, we investigated the effects of the HDAC inhibitor MS-275 on the radioresponse of DU145 prostate carcinoma xenografts. EXPERIMENTAL DESIGN: As an indicator of HDAC inhibition in vivo, the histone acetylation status in tumor lysates was determined after two, four, and six injections of MS-275 delivered at 12-hour intervals, as well as 24 and 48 hours after the last injection. Tumor growth delay studies were then performed using this DU-145 xenograft model with radiation administered to leg tumors after the fourth dose of MS-275, which corresponded to the time of maximum histone hyperacetylation. RESULTS: An increase in histone hyperacetylation was detected in each tumor after two injections of MS-275 with a maximum hyperacetylation occurring after four to six injections. In tumor growth delay studies, the combination of MS-275 and radiation resulted in a greater than additive inhibition of tumor growth as compared with the individual modalities. As alternative sources for an indicator of drug radiosensitizing activity, histone hyperacetylation was determined in a series of normal tissues, including lymphocytes. Each of the normal tissues also had a maximal histone hyperacetylation after four to six injections of MS-275. CONCLUSIONS: These studies show that MS-275 enhances the radiosensitivity of DU145 xenografts and suggest that histone hyperacetylation status can serve as a useful marker for drug radiosensitizing activity.

Acetylation↗

PubMed2004

Isoprostane levels in the urine of patients with prostate cancer receiving radiotherapy are not elevated.

PURPOSE: Previous studies have demonstrated that urinary 8-iso-prostaglandin F (PGF)2alpha serves as a powerful biomarker of lipid peroxidation in diseases in which oxidative stress plays an important role in its pathophysiology. The goal of this study was to measure the urinary isoprostane levels in patients with prostate cancer treated with radiotherapy (RT) in an effort to determine whether isoprostane levels are elevated compared with in historical controls, whether the levels increase after RT, and whether such an increase would correlate positively with the degree of GU symptoms during treatment. METHODS AND MATERIALS: Urine samples were obtained before and during RT from patients enrolled on a recently reported Phase III trial examining the therapeutic efficacy of ibuprofen in decreasing the acute urinary symptoms of RT. Radioimmunoassays were performed on urine samples for 8-iso-PGF2alpha or 15-keto-dihydro-PGF2alpha. RESULTS: Fifteen patients provided samples both before and during RT. The levels of 8-iso-PGF(2alpha) and 15-keto-dihydro-PGF2alpha in the urine samples obtained before prostate RT (0.27 and 0.41 nmol/mmol creatinine) did not differ appreciably from the values observed in a normal cohort (0.27 and 0.46 nmol/mmol creatinine) and did not change after RT (0.23 and 0.37 nmol/mmol creatinine). CONCLUSION: We were unable to detect an increase in either 8-iso-PGF2alpha or 15-keto-dihydro-PGF2alpha in the urine of patients with prostate cancer compared with in historical normal controls. We were also unable to measure an increase in either of the eicosanoids during RT to the prostate gland.

Anti-Inflammatory Agents, Non-Steroidal↗

PubMed2004

In vivo tumor imaging using a near-infrared-labeled endostatin molecule.

PURPOSE: Endostatin is a 20-kD C-terminal fragment of collagen XVIII and is a potent inhibitor of angiogenesis. Imaging technologies that use near-infrared (NIR) fluorescent probes are well suited to the laboratory setting. The goal of this study was to determine whether endostatin labeled with a NIR probe (Cy5.5) could be detected in an animal after intraperitoneal injection and whether it would selectively localize in a tumor. METHODS: Endostatin was conjugated to Cy5.5 monofunctional dye and purified from free dye by gel filtration. LLC, a murine tumor, was implanted in C57BL/6 mice. The tumors were allowed to grow to 350 mm(2), at which point the mice were injected with 100 microg/100 microL endostatin-Cy5.5 and imaged at various points under sedation. Imaging was performed using a lightproof box affixed to a fluorescent microscope mounted with a filter in the NIR bandwidth (absorbance maximum 675 nm and emission maximum 694 nm). Images were captured by a CCD and desktop computer and stored as 16-bit Tiff files. The mice were also serially imaged for uptake into the tumor and washout from the tumor. RESULTS: After intraperitoneal injection, endostatin-Cy5.5 was quickly absorbed, producing a NIR fluorescent image of the tumors at 24 h that persisted through 7 days. However, the signal peaked at 42 h after injection. Control animals included mice containing green fluorescent protein (GFP) under the control of an actin promotor, which expresses GFP in every cell; tumor-free mice injected with endostatin-Cy5.5; mice with tumors that were not injected with endostatin-Cy5.5; and mice with tumors injected with dye alone. In the four sets of control animals, no NIR photon emissions were detected at 24 hours or 5 days. Only the GFP mouse was detected using the GFP filter. Unlike previous analogous studies with 4-N-(S-glutathionylacetyl)amino) phenylarsenoxide (GSAO)-Cy5.5 in which the tumor image faded with time, the endostatin-Cy5.5 NIR signal was emitted from the tumor up to 7 days after injection, the last time point examined. CONCLUSION: The results of this study demonstrated that endostatin covalently bound to Cy5.5 will migrate from a distant intraperitoneal injection site to a tumor. These data indicate that endostatin-Cy5.5 is appropriate for selectively imaging tumors in experimental animals. Furthermore, data suggest that the anti-angiogenic effect of endostatin occurs through a local mechanism of action, within the tumor or tumor vasculature, rather than through a systemic mechanism.

Angiogenesis Inhibitors↗

PubMed2004

Urinary VEGF and MMP levels as predictive markers of 1-year progression-free survival in cancer patients treated with radiation therapy: a longitudinal study of protein kinetics throughout tumor progression and therapy.

PURPOSE: To determine the predictive value of urinary levels of two angiogenic factors, vascular endothelial growth factor (VEGF) and matrix metalloproteinase (MMPs), in a longitudinal study to determine their correlation with 1-year progression-free survival in patients with cancer. PATIENTS AND METHODS: VEGF and MMP levels were measured in the urine of 65 cancer patients at first evaluation, during therapy, and at follow-up (n = 242); normalized by creatinine levels; and compared with 16 healthy controls. The correlation of initial levels and trends of VEGF and MMPs with 1-year progression-free survival was assessed using two-sample tests and stepwise logistic regression. RESULTS: Urinary VEGF levels at presentation were different between patients with local-regional cancer and normal controls, and between patients with metastatic prostate cancer and local-regional disease (P =.04 and.01, respectively). Similar results were found with MMP measurement (P =.03 and.0001, respectively). Of those patients subsequently treated with radiation, VEGF levels at presentation between patients with no evidence of disease (NED) after radiation and those who had persistent or recurrent disease after radiotherapy were also different (P =.039). The comparison between angiogenic factor levels taken at least 1 month postradiotherapy and the last level taken during treatment was the strongest predictor of patient 1-year progression-free survival (P =.004). Similarly, the overall MMP trend was also significantly associated with 1-year progression-free survival, as was the individual MMP-2 trend (P =.004 and.001, respectively). Stepwise logistic regression revealed that the VEGF trend comparing postradiation levels with last level taken during treatment was an independent predictor of progression-free survival (P =.02). CONCLUSION: This small exploratory study suggests that the angiogenic urinary trends of VEGF and MMPs may be useful predictive markers for progression-free survival in cancer patients after the completion of radiotherapy.

Adult↗

PubMed2004

In vivo tumor imaging in mice with near-infrared labeled endostatin.

Endostatin is a potent inhibitor of angiogenesis currently in phase I clinical trials. Imaging technologies that use near-infrared fluorescent probes are well suited to the laboratory setting. The goal of this study was to determine whether endostatin labeled with a near-infrared probe (Cy5.5) could be detected in an animal and whether it would selectively localize to a tumor. Endostatin was conjugated to Cy5.5 monofunctional dye and injected into mice bearing Lewis lung carcinoma tumors (350 mm2). Mice were imaged at various time points while under sedation using a lightproof box affixed to a fluorescent microscope mounted with a filter in the near-infrared bandwidth consistent with Cy5.5 fluorescence. After i.p. injection, endostatin-Cy5.5 was absorbed producing a near-infrared fluorescent image within the tumors at 18 h reaching a maximum at 42 h after injection. No signal was emitted from mice injected with unlabeled endostatin or Cy5.5 dye alone or those that received no injection. Further results show that a dose response exists with injection of endostatin-Cy5.5. Mimicking the clinical route of administration, an i.v. injection had a peak signal emission at 3 h but also persisted to 72 h. Finally, to determine the intratumoral binding site for endostatin, we performed immunofluorescence on tumor specimens and demonstrated that endostatin binds to tumor vasculature and colocalizes with platelet/endothelial cell adhesion molecule 1 expression. This study demonstrates that endostatin covalently bound to Cy5.5 will migrate from a distant i.p. injection site to a tumor. These data indicate that endostatin-Cy5.5 is appropriate for selectively imaging tumors in uninjured experimental animals.

Animals↗

PubMed2003

Evaluation of copper chelation agents as anti-angiogenic therapy.

The design, synthesis and evaluation of N,N',N"-tris(2-pyridylmethyl)-cis,cis-1,3,5,-triaminocyclohexane (tachpyr, 1) derivatives as novel anti-angiogenic agents were performed in an in vitro endothelial cell proliferation assay to assess their cytotoxicity and selectivity. The selective nature of the anti-angiogenic agents for human umbilical vein endothelial cells (Huvec) was compared to a normal fibroblast cell line and a human Glioma cell line to evaluate these compounds. N,N',N"-tris(2-mercaptoethyl)-cis,cis-1,3,5-triaminocyclohexane trihydrochloride (3b) was superior to tachpyr in terms of selectivity of its inhibitory activity toward the proliferation of Huvec compared to the fibroblast and human Glioma cell lines.

Angiogenesis Inhibitors↗

PubMed2003

Radiation abscopal antitumor effect is mediated through p53.

The observation that radiation treatment to a local area of the body results in an antitumor effect for tumors distant to the radiation site has been termed the "abscopal effect." To understand the mechanism of this unusual phenomenon, we examined whether the effect was mediated through p53, a protein complex up-regulated in irradiated cells. Non-tumor-bearing legs of C57BL/6 (wild-type p53) and p53 null B6.129S2-Trp53(tm1Tyj) mice were irradiated to determine whether an abscopal effect could be observed against Lewis lung carcinoma (LLC) and T241 (fibrosarcoma) implanted at a distant site. In mice with wild-type p53, both LLC and T241 tumors implanted into the midline dorsum grew at a significantly slower rate when the leg of the animal was exposed to five 10-Gy fractions of radiation compared with sham-irradiated animals, suggesting that the abscopal effect is not tumor specific. When the radiation dose to the leg was reduced (twelve fractions of 2 Gy each), the inhibition of LLC tumor growth was decreased indicating a radiation-dose dependency for the abscopal effect. In contrast, when the legs of p53 null animals or wild-type p53 mice treated with pifithrin-alpha (a p53 blocker) were irradiated (five 10-Gy fractions), tumor growth was not delayed. These data implicate p53 as a key mediator of the radiation-induced abscopal effect and suggest that pathways downstream of p53 are important in eliciting this response.

Animals↗

PubMed2003

Antiangiogenic therapy through copper chelation.

As new compounds are being evaluated for use in clinical trials involving antiangiogenic therapies, two important factors must be considered. Independent of clinical efficacy, the potential drug must be cost-effective and have reasonable ease of production. The compound endostatin (Entremed, Inc.) has recently completed two Phase I trials with minimal toxicity to the patients treated [1,2]. However, due to the difficulty and expense of producing large quantities of a recombinant protein, Entremed Inc. has experienced financial difficulties [3]. As this company's fate indicates, a drug must not only be clinically effective, but must also possess reasonable production economics. Another interesting component of compound development is selectivity. Highly selective antiangiogenic compounds such as the tyrosine kinase inhibitor SU-5416 are being replaced by less selective compounds such as SU-6668, which acts on a broader spectrum of tyrosine kinase receptors [4]. This move towards using less selective antiangiogenic compounds is based on preclinical models that demonstrate both better clinical efficacy when using less specific molecules and low response rates from the more selective compounds. With the aim of further examining broadly-acting antiangiogenic agents, the authors are currently evaluating new classes of agents that preferentially bind copper and inhibit angiogenesis. Copper has been known to be a significant target for antiangiogenic therapy for a number of years [5]. Recently, through the use of molecular techniques, the target enzymes that utilise copper as a cofactor are being elucidated. This review will describe the historical use of anticopper therapy for the treatment of Wilson's disease and evaluate some of the new anticopper compounds currently under consideration for use in antiangiogenic therapy.

Angiogenesis Inhibitors↗