Faculty Bibliography

Gene transfer of p53 induces cell death in most cancer cells, and replication-defective adenoviral vectors expressing p53 are being evaluated in clinical trials. However, low transduction efficiency limits the efficacy of replication-defective vector systems for cancer therapy. The use of replication-competent vectors for gene delivery may have several advantages, holding the potential to multiply and spread the therapeutic agent after infection of only a few cells. However, expression of a transgene may adversely affect viral replication. We have constructed a replicating adenoviral vector (Adp53rc) that expresses high levels of p53 at a late time point in the viral life cycle and also contains a deletion of the adenoviral death protein (ADP). Adp53rc-infected cancer cells demonstrated high levels of p53 expression in parallel with the late expression pattern of the adenoviral fiber protein. p53 expression late in the viral life cycle did not impair effective virus propagation. Survival of several lung cancer cell lines was significantly diminished after infection with Adp53rc, compared with an identical p53-negative control virus. p53 expression also improved virus release and spread. Interestingly, p53 was more cytotoxic than the ADP in cancer cells but less cytotoxic than the ADP in normal cells. In conclusion, late expression of p53 from a replicating virus improves tumor cell killing and viral spread without impairing viral replication. In addition, in combination with a deletion of the ADP, specificity of tumor cell killing is improved.

4-Aminobiphenyl (4-ABP) is a major etiological agent for human bladder cancer. Metabolically activated 4-ABP is able to interact with DNA to form adducts that may induce mutations and initiate carcinogenesis. Thirty to sixty percent of bladder cancer has a mutation in the tumor suppressor p53 gene, and the mutational spectrum bears unique features. To date the DNA binding spectrum of 4-ABP in the p53 gene is not known due to the lack of methodology to detect 4-ABP-DNA adducts at nucleotide sequence level. We have found that UvrABC nuclease, a nucleotide excision repair complex isolated from Escherichia coli, is able to incise specifically and quantitatively DNA fragments modified with N-hydroxy-4-aminobiphenyl (N-OH-4-ABP), an activated intermediate of 4-ABP. Using the UvrABC nuclease incision method, we mapped the binding spectrum of N-OH-4-ABP in DNA fragments containing exons 5, 7, and 8 of the human p53 gene and also determined the effect of C5 cytosine methylation on N-OH-4-ABP-DNA binding. We found that codon 285, a mutational hotspot at a non-CpG site in bladder cancer, is the preferential binding site for N-OH-4-ABP. We also found that C5 cytosine methylation greatly enhanced N-OH-4-ABP binding at CpG sites, and that two mutational hotspots at CpG sites, codons 175 and 248, became preferential binding sites for N-OH-4-ABP only after being methylated. These results suggest that both the unique DNA binding specificity of 4-ABP and cytosine methylation contribute to the mutational spectrum of the p53 gene in human bladder cancer

Mutations in the p53 gene have been implicated to play an important role in the development of various human cancers. To evaluate the importance of p53 in lung cancer, a transgenic mouse model was established by utilizing the Clara cell secretory protein (CCSP) promoter to target the expression of a dominant-negative mutant form of p53 (dnp53) in the lung. In two transgenic CCSP-dnp53 founder lines, the dnp53 protein was expressed exclusively in the lungs. The incidence of spontaneous lung cancer in 18-month-old transgenic mice was 45%, whereas that in age-matched control mice was 20%. The relative risk of lung tumors in CCSP-dnp53 mice was 2.3 times that of wild-type mice (exact confidence limits of 0.69, 17.5). In addition to the increased incidence of spontaneous lung tumor, these mice were more susceptible to the development of lung adenocarcinoma after exposure to benzo(a)pyrene (BaP). Six months after intratracheal instillation of benzo(a)pyrene, the tumor incidence in wild-type and CCSP-dnp53 mice was 39% and 73%, respectively. The risk of lung tumors was 25.3 times greater in BaP-treated mice adjusted for transgene expression (95% confidence limits of 3.29, 678, mid-p corrected). These results suggest that p53 function is important for protecting mice from both spontaneous and BaP-induced lung cancers

STUDY OBJECTIVE:s: Although pulmonary mycetoma has been well-described in immunocompetent hosts, the only description in HIV-infected patients has been of 10 patients from our institution, from 1992 to 1995. To further investigate the impact of HIV status on the presentation and course of pulmonary mycetoma, we conducted a follow-up study. DESIGN: Retrospective review of all cases of pulmonary mycetoma at Bellevue Hospital from 1992 to 1999. SETTING: Patients were evaluated on the inpatient chest service and in the outpatient chest and HIV clinics of Bellevue Hospital in New York City. PATIENTS: We identified 74 patients with pulmonary mycetoma; 20 of them were HIV-infected (27%). INTERVENTIONS: The 20 HIV-infected patients were treated with antiretroviral and/or antifungal therapy. MEASUREMENTS AND RESULTS: Predisposing diseases were pulmonary tuberculosis (TB), Pneumocystis carinii pneumonia (PCP), or both TB and PCP. Seventeen patients had a CD4+ cell count of < 100 cells/ micro L at presentation. Hemoptysis was present in 13 patients, but was massive in only 1 patient. Cough was common. Of the 18 patients for whom follow-up was available, 11 received antifungal treatment and 7 were observed without therapy. Six patients received both antiretroviral and antifungal therapy. Disease progression occurred in 50%. Only five patients exhibited radiographic or clinical improvement. All five were treated with both antiretroviral and antifungal therapy. CONCLUSIONS: PCP is a risk factor for pulmonary mycetoma in the HIV-infected individual. HIV-infected patients with mycetomas have a significant rate of disease progression, although they rarely have life-threatening hemoptysis. A combination of antifungal and antiretroviral therapy may improve the clinical outcome in HIV-infected patients with pulmonary mycetoma

To control tuberculosis worldwide, the burden of adult pulmonary disease must be reduced. Although widely used, Mycobacterium bovis BCG vaccination given at birth does not protect against adult pulmonary disease. Therefore, postexposure vaccination of adults with mycobacterial antigens is being considered. We examined the effect of various mycobacterial antigens on mice with prior M. tuberculosis infection. Subcutaneous administration of live or heat-treated BCG with or without lipid adjuvants to infected mice induced increased antigen-specific T-cell proliferation but did not reduce the bacterial load in the lungs and caused larger lung granulomas. Similarly, additional mycobacterial antigen delivered directly to the lungs by aerosol infection with viable M. tuberculosis mixed with heat-killed Mycobacterium tuberculosis (1:1) also did not reduce the bacillary load but caused increased expression of tumor necrosis factor alpha (TNF-alpha) and interleukin 6 (IL-6), which was associated with larger granulomas in the lungs. When M. tuberculosis-infected mice were treated with recombinant BCG that secreted cytokines shown to reduce disease in a preinfection vaccine model, the BCG secreting TNF-alpha, and to a lesser extent, IL-2 and gamma interferon (IFN-gamma), caused a significant increase in granuloma size in the lungs. Moreover, treatment of M. tuberculosis-infected mice with recombinant murine TNF-alpha resulted in increased inflammation in the lungs and accelerated mortality without affecting the bacillary load. Taken together, these studies suggest that administration of mycobacterial antigens to mice with prior M. tuberculosis infection leads to immune activation that may exacerbate lung pathology via TNF-alpha-induced inflammation without reducing the bacillary load

STUDY OBJECTIVES: Patients with HIV-1 infection or AIDS may present with abnormal chest radiograph (CXR) findings in the absence of symptoms specific to the lung. The objective was to determine the spectrum of disease and the diagnostic modalities employed in these patients. METHODS: From 1996 to 1998, we identified patients with HIV-1 infection presenting to the Bellevue Hospital Chest Service with abnormal CXR findings, and absence of specific pulmonary symptoms. Charts were reviewed for presence of constitutional symptoms, CD4 lymphocyte count, use of Pneumocystis carinii pneumonia (PCP) prophylaxis, eventual diagnosis, and all diagnostic modalities employed. CXR findings were classified according to their predominant abnormalities: nodules, infiltrates, cavity, mass, adenopathy, or effusion. RESULTS: Forty-four patients were eligible for inclusion. Eight-six percent of patients had a CD4 lymphocyte count < 200 cells/microL, and 57% were receiving PCP prophylaxis. Nodular disease was the most common radiographic abnormality (57%), followed by adenopathy (17%). A definitive diagnosis was obtained in 86% of the patients. The most common diagnosis was tuberculosis (26%), followed by nontuberculous mycobacteria (NTM; 23%) and Kaposi sarcoma (12%). No patients had PCP or bacterial pneumonia. Sixty-two percent of patients required an invasive modality to establish a diagnosis. Only 18% of patients with tuberculosis (2 of 11 patients) received diagnoses by sputum analysis. CONCLUSIONS: Patients with HIV-1 infection, abnormal CXR findings, and lack of pulmonary symptoms have a high incidence of infectious disorders, especially pulmonary tuberculosis and infection due to NTM. The high prevalence of treatable and potentially communicable disorders warrants an aggressive diagnostic approach in these patients

Autosomal recessive deficiency of lysosomal acid maltase (GAA) or glycogen storage disease type II (GSDII) results in a spectrum of phenotypes including a rapidly fatal infantile disorder (Pompe's), juvenile, and a late-onset adult myopathy. The infantile onset form presents as hypotonia with massive accumulation of glycogen in skeletal and heart muscle, with death due to cardiorespiratory failure. Adult patients with the slowly progressive form develop severe skeletal muscle weakness and respiratory failure. Particle bombardment is a safe, efficient physical method in which high-density, subcellular-sized particles are accelerated to high velocity to carry DNA into cells. Because it does not depend on a specific ligand, receptor, or biochemical features on cell surfaces, particle-mediated gene transfer can be readily applied to a variety of systems. We evaluated particle bombardment as a delivery system for therapy of GSDII. We utilized a vector carrying the CMV promoter linked to the human GAA cDNA. Human GSDII cell lines (fibroblasts and lymphoid) as well as ex vivo with adult-onset peripheral blood cells (lymphocytes and monocytes) were transiently transfected by bombardment with a Helios gene gun delivering gold particles coated with the GAA expression plasmid. All cell types showed an increase in human GAA activity greater than 50% of normal activity. Subsequently, GAA -/- mice were treated every 2 weeks for 4 months by particle bombardment to the epidermis of the lower back and hind limbs. Muscle weakness in the hind and forelimbs was reversed. These data suggest that particle delivery of the GAA cDNA by the Helios gene gun may be a safe, effective treatment for GSDII