Laura Kasman - Academia.edu (original) (raw)

Papers by Laura Kasman

PubMed, Dec 27, 2023

Outcome data from 6 National Institutes of Health-funded Postbaccalaureate Research Education Pro... more Outcome data from 6 National Institutes of Health-funded Postbaccalaureate Research Education Programs (PREPs) in the Mid-Atlantic region were combined to give a multi-institutional perspective on their scholars' characteristics and progress through biomedical research training. The institutions hosting these programs were Johns Hopkins University School of Medicine, the Medical University of South Carolina, the University of Maryland School of Medicine, the University of North Carolina at Chapel Hill, Virginia Commonwealth University, and Virginia Polytechnic Institute and State University. The authors summarize the institutional pathways, demographics, undergraduate institutions, and graduate institutions for a total of 384 PREP scholars who completed the programs by June 2021. A total of 228 (59.4%) of these PREP scholars identified as Black or African American, 116 (30.2%) as Hispanic or Latinx, and 269 (70.0%) as female. The authors found that 376 of 384 scholars (97.9%) who started PREP finished their program, 319 of 376 (84.8%) who finished PREP matriculated into PhD or MD/PhD programs, and 284 of 319 (89.0%) who matriculated have obtained their PhD or are successfully making progress toward their PhD.

Cornea, Oct 1, 2006

Susceptibility to herpes stromal keratitis (HSK) is strongly influenced by genetic factors, as sh... more Susceptibility to herpes stromal keratitis (HSK) is strongly influenced by genetic factors, as shown by multiple rodent models using human herpes simplex virus. A single gene, encoding the immunoglobulin G (IgG) 2a heavy chain protein, confers susceptibility or resistance through a mechanism involving molecular mimicry in one mouse model. However, other rodent studies have produced contradictory results. This study tested the hypothesis that the GM23 gene (the human IgG2a homolog) influences susceptibility to HSK in humans. Methods: The study population consisted of all consenting patients

Applied and Environmental Microbiology, Aug 1, 1998

Activated forms of Bacillus thuringiensis insecticidal toxins have consistently been found to for... more Activated forms of Bacillus thuringiensis insecticidal toxins have consistently been found to form insoluble and inactive precipitates when they are expressed in Escherichia coli. Genetic engineering of these proteins to improve their effectiveness as biological pesticides would be greatly facilitated by the ability to express them in E. coli, since the molecular biology tools available for Bacillus are limited. To this end, we show that activated B. thuringiensis toxin (Cry1Ac) can be expressed in E. coli as a translational fusion with the minor phage coat protein of filamentous phage. Phage particles displaying this fusion protein were viable, infectious, and as lethal as pure toxin on a molar basis when the phage particles were fed to insects susceptible to native Cry1Ac. Enzyme-linked immunosorbent assay and Western blot analysis showed the fusion protein to be antigenically equivalent to native toxin, and micropanning with anti-Cry1Ac antibody was positive for the toxin-expressing phage. Phage display of B. thuringiensis toxins has many advantages over previous expression systems for these proteins and should make it possible to construct large libraries of toxin variants for screening or biopanning.

Journal of Applied Microbiology, Oct 18, 2010

To explore the preventative potential of muscadine grape skin (MGS) and the single flavonoid, que... more To explore the preventative potential of muscadine grape skin (MGS) and the single flavonoid, quercetin, as an alternative means for ameliorating Helicobacter pylori infection and/or the H. pylori-induced inflammatory response in mice. The antimicrobial and anti-inflammatory properties of MGS and quercetin, a major phenolic constituent, were evaluated against H. pylori in vitro and in vivo. The antimicrobial activity of quercetin was evaluated against 11 H. pylori strains in vitro with inhibition of all strains at 128-64 μg ml(-1) . In vivo studies showed a moderate reduction in H. pylori counts following treatment with 5 and 10% MGS or quercetin (25 mg kg(-1) body weight) in addition to significantly reduced inflammatory cytokines (TNF-α, IL-1β and IFN-γ) when compared with untreated mice. MGS and quercetin did not significantly reduce H. pylori growth in a mouse model. However, these products were effective in regulating the inflammatory response to H. pylori infection. Our results suggest that H. pylori infection may be reduced or prevented via the consumption of fruits rich in certain phenolic compounds (e.g. quercetin) such as muscadine grapes.

The Journal of Urology, Sep 1, 2009

Purpose-TRAIL, an endogenous protein involved in immunosurveillance and a novel drug in clinical ... more Purpose-TRAIL, an endogenous protein involved in immunosurveillance and a novel drug in clinical trials, is of particular interest as a cancer therapeutic because it can induce apoptosis in cancer cells but not in normal cells. Since some cancers develop resistance to TRAIL, safe and effective methods of TRAIL sensitization are of great clinical interest. This study explores how chemotherapy and oxidative stress affect TRAIL sensitivity and expression of proteins in the apoptotic pathway. Materials and Methods-Sensitivity to TRAIL was assessed in viability assays. Apoptosis was measured by caspase-3/7 activity and/or nuclear condensation using Hoechst staining. Western blotting was used to determine cleavage, phosphorylation, or alterations in protein expression. Results-TRAIL reduced the viability of 5637 but not J82 and T24 bladder carcinoma cells. Chemotherapy with doxorubicin or cisplatin decreased the expression of the anti-apoptotic protein cFLIP S and increased caspase-8 cleavage, reversing TRAIL resistance in T24 cells. Specific targeting of cFLIP S by siRNA was insufficient for sensitization to TRAIL in T24 cells. However, chemotherapy-mediated TRAIL sensitization was mimicked by low concentrations of hydrogen peroxide, which resulted in phosphorylation of translation elongation factor 2 (EF2) and reduced expression of several short half-life, anti-apoptotic proteins including FLIP S , XIAP, and survivin. Conclusions-Induction of oxidative stress by low concentrations of hydrogen peroxide may reverse TRAIL resistance and warrants the further exploration of hydrogen peroxide as an adjuvant intravesical treatment to lower the apoptotic threshold of bladder cancer cells.

Free Radical Biology and Medicine, Nov 1, 2007

We have previously shown that doxorubicin sensitizes prostate cancer cells to TNF-Related Apoptos... more We have previously shown that doxorubicin sensitizes prostate cancer cells to TNF-Related Apoptosis Inducing Ligand (TRAIL). Sensitization correlated with decreased expression of the antiapoptotic protein cFLIP S. The decrease in cFLIP S could not be explained by transcriptional regulation or increased degradation, leading us to focus on translational mechanisms. In this study, we found that doxorubicin caused strong and sustained phosphorylation of elongation factor 2 (EF-2), which interferes with protein elongation. Phosphorylation of EF-2 appeared to occur in a kinaseindependent manner. Treatment with hydrogen peroxide recapitulated the events observed after doxorubicin treatment. In addition, cells treated with hydrogen peroxide expressed less XIAP and survivin which, like cFLIP S , are short half-life proteins with an anti-apoptotic function while expression levels of DR5, caspases-8,-9,-3, and Bax are maintained. The doxorubicin-mediated decrease in cFLIP S and XIAP as well as TRAIL-induced apoptosis was prevented by pretreatment with an iron chelator, indicating that expression of these proteins was affected by free radical generation upon interaction of iron with doxorubicin. In conclusion, our data suggest that free radicals can affect the phosphorylation of EF-2 resulting in a net loss of short half-life proteins such as cFLIP S and XIAP, leaving a cell more vulnerable to apoptotic stimuli.

Virology, Mar 1, 2005

CD13/aminopeptidase N is a membrane-bound metalloproteinase implicated in human cytomegalovirus (... more CD13/aminopeptidase N is a membrane-bound metalloproteinase implicated in human cytomegalovirus (HCMV) infection and pathogenesis. Anti-CD13 antibodies can neutralize HCMV infectivity, and HCMV viremia after bone marrow transplantation induces anti-CD13 autoantibodies which correlate with development of chronic graft vs. host disease. We examined whether murine CD13/APN was similarly implicated in murine cytomegalovirus (MCMV) disease. MCMV infection did induce anti-CD13 antibodies in mice in a strainspecific manner. ICR and 129S mice developed high titers of anti-CD13 antibodies and anti-MCMV antibodies after MCMV infection, whereas CBA and CBAxC57BL/6 f1 hybrid mice produced antibodies against MCMV only. Unlike HCMV, no evidence was found for a correlation between host cell CD13/APN expression and infection, or for the presence of CD13/APN on MCMV particles, although APN inhibitors decreased MCMV plaque formation. Reproduction of CD13/APN autoantibody production in the murine system should make it possible to determine if these antibodies contribute to CMV pathogenesis.

Cancer Gene Therapy, Dec 22, 2006

Gene therapy of cancer using adenovirus as a single treatment modality has met limited success an... more Gene therapy of cancer using adenovirus as a single treatment modality has met limited success and efforts to enhance therapeutic outcomes have included combination of gene therapy with chemotherapy. The goal of this study was to investigate which chemotherapeutic agents may be suitable for combination with gene therapy of prostate cancer. Using an adenovirus expressing green fluorescent protein (GFP), we determined the effect of cisplatin, gemcitabine, doxorubicin, depsipeptide and MS-275 on adenoviral infectivity and transgene expression in LNCaP cells. We found that the two histone deacetylase inhibitors (HDACi), depsipeptide and MS-275, and to a lesser extent doxorubicin, increased infectivity and transgene expression. However, only the HDACi selectively increased infectivity in LNCaP cells while doxorubicin increased infectivity to a greater extent in normal prostate epithelial cells (PrEC). The increase in infectivity but not transgene expression correlated to increased surface expression of coxsackie and adenovirus receptor (CAR). Increased transgene expression following infection with an adenovirus expressing tumor necrosis factor-related apoptosis inducing ligand (TRAIL) was observed only in LNCaP cells treated with depsipeptide or MS-275. Combination of TRAIL gene therapy with HDACi but not doxorubicin resulted in increased induction of apoptosis in LNCaP cells. In contrast, apoptosis was not enhanced by HDACi in normal PrEC. These results suggest that combination of HDACi with adenoviral TRAIL gene therapy may be a new therapeutic approach for the treatment of prostate cancer that warrants further investigation.

Journal of Visualized Experiments, Dec 1, 2013

Bladder cancer is the second most common cancer of the urogenital tract and novel therapeutic app... more Bladder cancer is the second most common cancer of the urogenital tract and novel therapeutic approaches that can reduce recurrence and progression are needed. The tumor microenvironment can significantly influence tumor development and therapy response. It is therefore often desirable to grow tumor cells in the organ from which they originated. This protocol describes an orthotopic model of bladder cancer, in which MB49 murine bladder carcinoma cells are instilled into the bladder via catheterization. Successful tumor cell implantation in this model requires disruption of the protective glycosaminoglycan layer, which can be accomplished by physical or chemical means. In our protocol the bladder is treated with trypsin prior to cell instillation. Catheterization of the bladder can also be used to deliver therapeutics once the tumors are established. This protocol describes the delivery of an adenoviral construct that expresses a luciferase reporter gene. While our protocol has been optimized for short-term studies and focuses on gene delivery, the methodology of mouse bladder catheterization has broad applications.

BMC Cancer, May 12, 2011

Background: Bladder cancer, the 5 th most common malignancy in the USA, is often detected as a re... more Background: Bladder cancer, the 5 th most common malignancy in the USA, is often detected as a result of incidental findings or by presenting hematuria. Once diagnosed the disease is one of the costliest cancers to treat due to frequent, invasive and often lifelong follow-up procedures. Because cells are shed into urine, there has been an emerging effort to develop non-invasive tests for the detection of bladder cancer. Expression of survivin, a member of the inhibitor of apoptosis protein family, has been associated with bladder cancer. Therefore, the goal of this study was to determine the feasibility of transducing viable exfoliated cells obtained from urine with an adenoviral vector in which a reporter gene is under the control of the survivin promoter. Methods: Exfoliated cells from urine were obtained from 36 human subjects (> 40 years old). An adenovirus in which GFP expression is under control of the survivin promoter (Ad.Surv.GFP) was generated. An adenovirus in which GFP is expressed from the CMV promoter served as a control. GFP expression was analyzed by fluorescent microscopy and quantified by flow cytometry. Results: Short-term cultures from exfoliated cells in urine could be established in 16 of 31 samples. These cultures were successfully transduced with Ad.CMV.GFP. Analysis of GFP expression following transduction with Ad.Surv.GFP, indicated that the survivin promoter was preferentially active in UM-UC-3 bladder cancer cells compared to nonmalignant UROtsa cells. Interestingly, baseline levels of GFP expression in cultures from exfoliated cells in urine exhibited higher baseline levels than UROtsa following transduction with Ad.Surv.GFP. Conclusions: We demonstrated the feasibility of establishing and analysing short-term cultures isolated from exfoliated cells in voided urine by means of adenoviral transduction, thereby forming the foundation for future studies to determine the specificity and sensitivity of a non-invasive test based on survivin promoter activity.

Journal of Virology, Jun 1, 2002

Prior observations of phage-host systems in vitro have led to the conclusion that susceptible hos... more Prior observations of phage-host systems in vitro have led to the conclusion that susceptible host cell populations must reach a critical density before phage replication can occur. Such a replication threshold density would have broad implications for the therapeutic use of phage. In this report, we demonstrate experimentally that no such replication threshold exists and explain the previous data used to support the existence of the threshold in terms of a classical model of the kinetics of colloidal particle interactions in solution. This result leads us to conclude that the frequently used measure of multiplicity of infection (MOI), computed as the ratio of the number of phage to the number of cells, is generally inappropriate for situations in which cell concentrations are less than 10 7 /ml. In its place, we propose an alternative measure, MOI actual , that takes into account the cell concentration and adsorption time. Properties of this function are elucidated that explain the demonstrated usefulness of MOI at high cell densities, as well as some unexpected consequences at low concentrations. In addition, the concept of MOI actual allows us to write simple formulas for computing practical quantities, such as the number of phage sufficient to infect 99.99% of host cells at arbitrary concentrations.

Virology Journal, Apr 15, 2005

Background: Growth characteristics of coliphage viruses indicate that they are adapted to live wi... more Background: Growth characteristics of coliphage viruses indicate that they are adapted to live with their Eschericia coli hosts in the intestinal tract. However, coliphage experimentally introduced by ingestion persist only transiently if at all in the gut of humans and other animals. This study attempted to identify the barriers to long term establishment of exogenous coliphage in the gastrointestinal (GI) tracts of laboratory mice. Intestinal contents were screened for the presence of coliphage and host bacteria, and strains of E. coli bacteria from different segments of the GI tract were tested for susceptibility to six common laboratory coliphages. Results: Contrary to expectations, coliphage were not evident in the GI tracts of laboratory mice, although they were occasionally detected in feces. Commensal flora showed extreme variability within groups of mice despite identical handling and diet. Less than 20% of 48 mice tested carried E. coli in their gut, and of 22 commensal E. coli strains isolated and tested, 59% were completely resistant to infection by lambda, M13, P1, T4, T7, and PhiX174 coliphage. Lysogeny could not be demonstrated in the commensal strains as mitomycin C failed to induce detectable phage. Preexisting immunity to phages was not evident as sera and fecal washes did not contain significant antibody titers to six laboratory phage types. Conclusion: Lack of sufficient susceptible host bacteria seems to be the most likely barrier to establishment of new coliphage infections in the mouse gut.

Bladder, Feb 26, 2016

OBJECTIVE-The MB49 syngeneic, murine model of bladder cancer has been widely used for more than 3... more OBJECTIVE-The MB49 syngeneic, murine model of bladder cancer has been widely used for more than 35 years. In humans, bladder cancer is one third as prevalent in women as in men, with a trend toward lower prevalence in parous compared to nulliparous women. Our objective was to determine if the MB49 bladder cancer model reproduces the sex differences observed in humans, and to determine its sensitivity to testosterone and the pregnancy hormone, human chorionic gonadotropin (hCG). METHODS-Male and female C57BL/6 mice were implanted with MB49 murine bladder cancer cells, and observed for tumor growth. MB49 dose responses to hCG and dihydrotestosterone were determined in vitro. RESULTS-MB49 tumor growth was significantly greater in male mice than female mice. Pregnancy did not affect MB49 tumor growth in female mice. MB49 cells did not proliferate in response to hCG in vitro and the functional receptor for gonadotropins was absent. Dihydrotestosterone strongly stimulated growth of MB49 cells in vitro. CONCLUSIONS-The MB49 murine model of bladder cancer reproduced some aspects of the sex differences observed in humans. Our results suggest that testosterone may stimulate MB49 cell proliferation, which may explain the more rapid MB49 tumor growth observed in male mice.

Molecular Pharmaceutics, Aug 5, 2009

The application of adenoviral gene therapy for cancer is limited by immune clearance of the virus... more The application of adenoviral gene therapy for cancer is limited by immune clearance of the virus as well as poor transduction efficiency, since the protein used for viral entry (CAR) serves physiological functions in adhesion and is frequently decreased among cancer cells. Cationic polymers have been used to enhance adenoviral gene delivery but novel polymers with low toxicity are needed to realize this approach. We recently identified polymers that were characterized by high transfection efficiency of plasmid DNA and a low toxicity profile. In this study we evaluated the novel cationic polymer EGDE-3,3′ for its potential to increase adenoviral transduction of the CARnegative bladder cancer cell line TCCSUP. The amount of adenovirus required to transduce 50-60% of the cells was reduced 100-fold when Ad.GFP was pre-incubated with the EGDE-3,3′ polymer. Polyethyleneimine (pEI), a positively charged polymer currently used as a standard for enhancing adenoviral transduction, also increased infectivity, but transgene expression was consistently higher with EGDE-3,3′. In addition, EGDE-3,3′-supplemented transduction of an adenovirus expressing an apoptosis inducing transgene, Ad.GFP-TRAIL, significantly enhanced the amount of cell death. Thus, our results indicate that novel biocompatible polymers may be useful in improving the delivery of adenoviral gene therapy.

Frontiers in Immunology, Sep 8, 2022

According to the American Centers for Disease Control and Prevention, people in all age groups ca... more According to the American Centers for Disease Control and Prevention, people in all age groups catch two or more "colds" per year, at least half of which are caused by human rhinoviruses. Despite decades of effort, there are no vaccines or drugs against rhinovirus infections and even social distancing measures that were effective in reducing the spread of the pandemic coronavirus, SARS-CoV-2, did not reduce the rate of rhinovirus detection. Fortunately, most rhinovirus strains are naturally attenuated in that they are not associated with serious illness, hospitalization or mortality. Instead, rhinoviruses are one of the most frequent viruses found in nasal swabs of asymptomatic, healthy people. Since rhinovirus infections cannot be avoided, a rational approach would be to engineer them for the benefit of their human hosts. Rhinovirus infections naturally induce robust mucosal and serum immune responses to all virusexpressed proteins. Several replication-competent, human rhinovirus vaccine vectors able to express protective antigens for other pathogens have already been designed and tested in animal models. With this strategy, the inevitable common cold would be able to induce immunity not just to a specific rhinovirus serotype but to other more pathogenic respiratory viruses as well. This article reviews existing rhinovirus vaccine vector technology and describes the characteristics that make live-attenuated rhinoviruses attractive vaccine candidates for SARS-CoV-2 and other pathogenic respiratory viruses in the future.

Prostate Cancer, 2012

Adenoviral gene therapy using the death receptor ligand TRAIL as the therapeutic transgene can be... more Adenoviral gene therapy using the death receptor ligand TRAIL as the therapeutic transgene can be safely administered via intraprostatic injection but has not been evaluated for efficacy in patients. Here we investigated the efficacy of adenoviral TRAIL gene therapy in a model of castration resistant prostate cancer and found that intratumoral injections can significantly delay tumor growth but cannot eliminate established lesions. We hypothesized that an underlying cause is inefficient adenoviral delivery. Using the LNCaP progression model of prostate cancer we show that surface CAR expression decreases with increasing tumorigenicity and that castration resistant C4-2b cells were more difficult to transduce with adenovirus than castration sensitive LNCaP cells. Many genes, including CAR, are epigenetically silenced during transformation but a new class of chemotherapeutic agents, known as histone deacetylase inhibitors (HDACi), can reverse this process. We demonstrate that HDACi restore CAR expression and infectivity in C4-2b cells and enhance caspase activation in response to infection with a TRAIL adenovirus. We also show that in cells with high surface CAR expression, HDACi further enhance transgene expression from the CMV promoter. Thus HDACi have multiple beneficial effects, which may enhance not only viral but also non-viral gene therapy of castration resistant prostate cancer.

Microbiology, 2000

Autographa californicaM nucleopolyhedrovirus (AcMNPV) is the prototypical member of theNucleopoly... more Autographa californicaM nucleopolyhedrovirus (AcMNPV) is the prototypical member of theNucleopolyhedrosisgenus of theBaculoviridae, a family of large, double-stranded DNA viruses that are highly diverse. Nucleocapsid morphogenesis of AcMNPV and others in theNucleopolyhedrovirusgenus takes place within the nuclei of infected host cells. Previously, we showed that filamentous actin (F-actin) is essential for this process to occur in AcMNPV-infected cells, an unprecedented finding for a DNA virus that replicates within the nucleus. Because of the fundamental importance of this requirement to our understanding of virus–host interactions, and because of the diversity of viruses included within theNucleopolyhedrovirusgenus, we were compelled to determine whether the replication of other nucleopolyhedroviruses was also F-actin dependent. We report here that progeny virus production of six other lepidopteran nucleopolyhedroviruses, representing both phylogenetic groups I and II within the g...

Journal of Controlled Release, Feb 28, 2014

Gene therapy has garnered significant attention as a therapeutic approach for bladder cancer but ... more Gene therapy has garnered significant attention as a therapeutic approach for bladder cancer but efficient delivery and gene expression remain major hurdles. The goal of this study was to determine if cationic polymers can enhance adenoviral gene expression in cells that are difficult to transduce in vitro and to subsequently investigate lead candidates for their capacity to increase adenoviral gene expression in an orthotopic in vivo model of bladder cancer. In vitro screening of linear polyamine-based and aminoglycoside-based polymer libraries identified several candidates that enhanced adenoviral reporter gene expression in vitro. The polyamine-based polymer NPGDE-1,4 Bis significantly enhanced adenoviral gene expression in the orthotopic model of bladder cancer but unfortunately further use of this polymer was limited by toxicity. In contrast, the aminoglycoside-based polymer paromomycin-BGDE, enhanced adenoviral gene expression within the bladder without adverse events. Our study demonstrates for the first time that cationic polymers can enhance adenoviral gene expression in an orthotopic model of bladder cancer, thereby providing the foundation for future studies to determine therapeutic benefits of polymeradenovirus combination in bladder cancer gene therapy.