Nuclear YB-1 expression as a negative prognostic marker in nonsmall cell lung cancer

The human Y-box binding protein, YB-1, is a multifunctional protein that regulates gene expression. Nuclear expression of YB-1 has been associated with chemoresistance and poor prognosis of tumour patients. Representative samples from autopsied material of primary tumours from 77 patients with NSCLC were investigated by immunohistochemistry for subcellular distribution of YB-1 and p53, in order to evaluate the prognostic role of nuclear expression of YB-1. Cytoplasmic YB-1 expression was found in all tumour samples, whereas nuclear expression was only observed in 48%. There was no correlation with histological classification, clinical parameters or tumour size, stage and metastasis status. However, patients with positive nuclear YB-1 expression in tumours showed reduced survival times when compared with patients without nuclear expression. Including information about the histology and mutational status for p53 increased the prognostic value of nuclear YB-1. Patients with nuclear YB-1 expression and p53 mutations had the worst prognosis (median survival 3 months), while best outcome was found in patients with no nuclear YB-1 and wildtype p53 (median survival 15 months). This suggests that the combined analysis of both markers allows a better identification of subgroups with varying prognosis. Nuclear expression of Y-box binding protien seems to be an independent prognostic marker.

Development of synthetic pan-selectin antagonists: a new treatment strategy for chronic inflammation in asthma

Asthma is characterized by chronic inflammation of large and small airways maintained by extravasation of leukocytes from the bloodstream into the surrounding peribronchial tissue. The process of extravasation is of crucial importance in inflammation and is mediated by a sequenced and concerted action between different adhesion molecules on endothelial cells and ligands on leukocytes. In this context, initial rolling and tethering is generally considered to be the primary event which is mediated by selectins, a family of glycoproteins comprised of E-, P- and L-selectin. Their role in asthma has been demonstrated in a variety of animal models, showing that all three selectins are involved in the chronic inflammation in asthma. Therefore, selectins are an attractive target where pan-selectin antagonism is the desired treatment strategy. Here, we give an overview of the status of the preclinical and clinical development of bimosiamose, the most advanced synthetic pan-selectin antagonist as a treatment for asthma.

Coexpression of p21(WAF1/CIP1) in adenovirus vector transfected human primary hepatocytes prevents apoptosis resulting in improved transgene expression

Replication-deficient adenovirus (Ad vector) is one of the most effective gene transfer systems. However, its employment in human gene therapy trials is hampered by Ad vector associated cytotoxicity and induction of apoptosis of the infected cells. Here, we identify one underlying mechanism as uncoupling of S phase and mitosis of the cell cycle leading to apoptosis and decline of transgene expression. Moreover, we demonstrate a strategy to avoid Ad vector associated cytotoxicity and induction of apoptosis in human primary hepatocytes by coinfection of Ad vector carrying the cDNA of choice and the cell cycle regulator p21(WAF1/CIP1) (p21). In addition, animal experiments were performed using Ad vector directed coexpression of p21 and human alpha 1-antitrypsin. As serum analysis of alpha 1-antitrypsin after Ad vector mediated gene transfer to the liver of mice revealed, this strategy resulted also in the improvement of transgene expression by two orders of magnitude. These data suggest that coexpression of p21 and Ad vector carrying a therapeutic gene may be a promising strategy to avoid cytotoxicity and induction of apoptosis leading to improved safety in human gene therapy.

Somatic mosaicism and variable penetrance in doublecortin-associated migration disorders

X-linked isolated lissencephaly sequence (XLIS) and subcortical band heterotopia (SBH) are allelic disorders caused by mutations in the doublecortin (DCX) gene. This genetic analysis of seven families revealed four novel mutations in the DCX gene. The authors detected a high rate of somatic mosaicism in male and female patients with variable penetrance of bilateral SBH including nonpenetrance in a heterozygous woman. In addition, the authors implemented prenatal diagnosis in a family with SBH/XLIS.

BALF N-acetylglucosaminidase and beta-galactosidase activities in idiopathic pulmonary fibrosis

The lysosomal enzymes N-acetylglucosaminidase (N-ACGA) and beta-galactosidase (beta-gal) are involved in cellular collagen metabolism and may, therefore, be markers of fibrosis in idiopathic interstitial pneumonias, such as idiopathic pulmonary fibrosis (IPF). N-ACGA and beta-gal were analyzed in the bronchoalveolar lavage fluid (BALF) of patients with the histologic pattern of usual interstitial pneumonia (UIP, n=10) and controls (n=9). Cellular distribution in BALF as well as the concentration of TGF-beta a well-known mediator of fibroblast matrix deposition were correlated to the enzyme activities in both groups of patients. We found that both, N-ACGA (UIP: 25.2 nmol/l s +/- 3.4; controls: 73 nmol/l s +/- 1.3) and beta-gal (UIP: 4.7 nmol/l s +/- 0.5; controls: 2.4 nmol/l s +/- 0.3) were elevated significantly in BALF of patients with IPF compared to that of control patients (P<0.003). This increase was paralleled by an increase in neutrophils (IPF: 17.9% +/- 21.8; controls: 5.4% +/- 6.3; P=0.03) and eosinophils (IPF: 2.0% +/- 1.5; controls: 0.2% +/- 0.45; P=0.002) in BALF fluid. In addition, N-ACGA activity correlated closely with lung function (FVC, TLC, and DLCO), transforming growth factor-beta (TGF-beta) in BALF (r=0.77, P=0.008) and activated lymphocytes (r=0.66, P=0.0021). Our findings suggest that measurement of lysosomal enzymes such as N-ACGA may represent a useful indicator of fibrotic activity in IPF.

Adenovirus-mediated E2F-1 gene transfer in nonsmall-cell lung cancer induces cell growth arrest and apoptosis

Since overexpression of E2F-1 has been shown to induce apoptosis, the ability of adenovirus-mediated transfer of E2F-1 to inhibit tumour growth in nonsmall-cell lung cancer cell lines was investigated. Three cell lines with various genomic status were infected with AdE2F. Cell proliferation and viability were determined by trypan blue exclusion. Apoptosis induction was assessed by flow cytometry and poly-adenosine diphosphate-ribose-polymerase cleavage assay. In vivo, the effect of E2F-1 on tumour growth was determined in severe combined immunodeficiency (SCID) mice. The current experiments showed that overexpression of E2F-1 suppressed tumour cell growth. The population of apoptotic cells was dramatically increased 96 h after infection with AdE2F. Inhibition of cell growth and induction of apoptosis was not dependent on genomic status. Moreover, treatment of implanted tumours in SCID mice with AdE2F inhibited tumour growth. These data suggest that adenovirus-mediated E2F-1 gene therapy may be effective in the treatment of nonsmall-cell lung cancer.

BAX and p16INK4A are independent positive prognostic markers for advanced tumour stage of nonsmall cell lung cancer

Clinical studies suggest prognostic relevance of p16INK4A in nonsmall cell lung cancer (NSCLC) while conflicting results for p53 have been published. However, the importance of the apoptosis regulating gene BAX, a downstream regulator of p53, on the prognosis of NSCLC is unknown. The present study investigated the prognostic relevance of BAX with respect to the status of p53 and P16INK4A in 61 patients with advanced NSCLC. Protein expression of BAX, p53 and p16INK4A was investigated retrospectively by immunohistochemistry. Tumour deoxyribonucleic acid (DNA) was screened for p53 mutations by single strand-conformation polymorphism polymerase chain reaction (PCR) and BAX frameshift mutations by fragment length analysis. Patients with positive BAX protein expression had a significantly longer median survival (14 months) than those patients without BAX expression (6 months, p=0.0004). In contrast, p53 status did not influence prognosis. Patients with p161NK4A negative tumours had a significantly shorter survival (4 months) than those with p16INK41 protein expression (15 months, p=0.0001). Furthermore, the loss of p16INK4A protein expression correlated strongly with the pressure of distant and advanced lymph-node metastases. The best survival was seen in a subgroup of 20 patients with positive p16INK4A expression and intact BAX (p=0.0002). The results of the present study suggest that the loss of BAX and p16INK4A expression are independent markers for poor prognosis in nonsmall cell lung cancer. The study suggests that multimarker analysis of genes involved in apoptosis may be useful for determining individual therapy and for identifying targets for gene-replacement therapy. This should be assessed in a prospective study with a larger cohort of patients.

Gene transfer into solid tumours--is a special application device beneficial?

The replacement of inactivated tumour suppressor genes is a promising approach in cancer therapy. The aim of this study was to evaluate the influence of technical determinants on the efficiency of adenoviral-mediated gene transfer into solid tumours. Therefore, we compared the efficacy of two different injection needle types, a conventional needle and a modified needle characterised by perforations at the side of the shaft in vivo. The total amount of adenoviral vector DNA and the activity of the transferred reporter gene were quantitatively analysed by polymerase chain reaction (PCR) specific for the E4 region of the Ad vector genome and the beta-galactosidase assay, respectively. The levels of adenoviral DNA, as well as the total beta-galactosidase activity, varied widely, but were not significantly different for the two groups. These results suggest, that the efficiency of intratumoral gene transfer cannot be improved by the design of the application device.

Analysis of p53/BAX/p16(ink4a/CDKN2) in esophageal squamous cell carcinoma: high BAX and p16(ink4a/CDKN2) identifies patients with good prognosis

PURPOSE

We have previously shown that loss of BAX expression is a negative prognostic factor in metastatic colorectal cancer. In the present study, we addressed the prognostic relevance of BAX and its upstream regulator p53 in squamous cell carcinoma (SCC) of the esophagus. Analysis of p16(ink4a/CDKN2) was included because p16(ink4a/CDKN2) and p53 were shown previously to cooperate during induction of cell cycle arrest and apoptosis.

PATIENTS AND METHODS

Retrospective analysis of 53 patients with curative intended R0 resection of esophageal SCC was done. Protein expression of BAX, p53, and p16(ink4a/CDKN2) was investigated by immunohistochemistry. In addition, tumor DNA was screened for BAX frameshift mutations by fragment length analysis and for p53 mutations by single-strand conformation polymorphism-polymerase chain reaction.

RESULTS

Overall median survival was 13.7 months. Patients with high BAX protein expression had a median survival of 19.5 months versus 8.0 months with low BAX expression (P <.005). High p16(ink4a/CDKN2) protein expression was associated with a median survival of 23.8 months versus 9.7 months with low p16(ink4a/CDKN2) (P =.011). The best survival (median, 45.8 months) was seen in a subgroup of 12 patients whose tumors bore the combination of both favorite phenotypes (ie, high BAX and high p16(ink4a/CDKN2) protein expression).

CONCLUSION

In this retrospective investigation, the combined analysis of BAX and p16(ink4a/CDKN2) shows subgroups in SCC of the esophagus with favorable (p16(ink4a/CDKN2)/BAX high expressing) or poor prognosis (loss of p16(ink4a/CDKN2)/loss of BAX). We suggest that such a multimarker analysis of apoptosis pathways could be useful for individualization of therapeutic strategies in the future, and suggest prospective studies to confirm these results.

Enteroendocrine localization of GLP-2 receptor expression in humans and rodents

BACKGROUND & AIMS

Glucagon-like peptide (GLP)-2, a product of the proglucagon gene, is expressed in enteroendocrine cells of the small and large intestine and is trophic to the gastrointestinal mucosa. GLP-2 also inhibits gastric acid secretion and emptying and up-regulates intestinal hexose transport. GLP-2 acts via binding to a single G protein-coupled GLP-2 receptor (GLP-2R), but the cellular targets for the diverse actions of GLP-2 remain unknown.

METHODS

GLP-2R expression in rodent and human tissues was examined using a combination of Northern blotting, reverse-transcription polymerase chain reaction (RT-PCR), and immunocytochemistry.

RESULTS

A single major GLP-2R messenger RNA transcript was detected by Northern blot analysis in rodent stomach, duodenum, jejunum, ileum, and colon, but not in rodent esophagus. GLP-2R expression was also detected by RT-PCR in RNA from the hypothalamus, brain stem, and lung. Immunocytochemical localization of human GLP-2R expression using specific antisera detected GLP-2R immunopositivity in subsets of endocrine cell populations in the epithelium of the stomach and both the small and large bowel.

CONCLUSIONS

These findings suggest that enteroendocrine-derived GLP-2 acts directly on endocrine cells to induce one or more downstream mediators of GLP-2 action in the gastrointestinal tract.

Impaired BAX protein expression in breast cancer: mutational analysis of the BAX and the p53 gene

We have previously shown that the pro-apoptotic BAX protein is differentially expressed in breast cancer and in other epithelial tumors. In this line, a reduced BAX protein expression is a negative prognostic factor in various carcinomas including breast cancer. For p53, a trancriptional activator of BAX in apoptosis, mutations in the coding sequence were shown to modulate BAX protein expression in cell line models on the transcriptional level. We therefore investigated the BAX gene in 68 breast cancer specimens for the presence of mutations in the coding sequence by single-strand conformation polymorphism (SSCP)-PCR and direct sequencing. The expression of BAX protein was assessed by immunohistochemistry. In addition, we screened for mutations in the exons 5-8 of the p53 gene by SSCP-PCR to assess whether mutations in the DNA-binding domain of this upstream regulator of BAX gene transcription are responsible for differences in BAX protein expression. As previously observed, BAX was differentially expressed in the breast cancer samples, but no mutations in the coding sequence of the BAX gene were found besides a polymorphism in exon 6 at the position 552 (G->A) and additional intronic polymorphisms. In contrast, we identified 16 of 68 (23.5%) tumors to bear mutations in the p53 gene. In the subset of BAX-expressing tumors, the mutational inactivation of p53 did result in a reduced BAX protein expression (Fisher exact test, p = 0. 047). Nevertheless, we identified a subset of BAX-negative tumors lacking BAX or p53 mutations. Thus, additional, not yet identified regulators, apart from p53, appear to be involved in the regulation of BAX protein expression.

Impaired BAX protein expression in breast cancer: mutational analysis of the BAX and the p53 gene

We have previously shown that the pro-apoptotic BAX protein is differentially expressed in breast cancer and in other epithelial tumors. In this line, a reduced BAX protein expression is a negative prognostic factor in various carcinomas including breast cancer. For p53, a trancriptional activator of BAX in apoptosis, mutations in the coding sequence were shown to modulate BAX protein expression in cell line models on the transcriptional level. We therefore investigated the BAX gene in 68 breast cancer specimens for the presence of mutations in the coding sequence by single-strand conformation polymorphism (SSCP)-PCR and direct sequencing. The expression of BAX protein was assessed by immunohistochemistry. In addition, we screened for mutations in the exons 5-8 of the p53 gene by SSCP-PCR to assess whether mutations in the DNA-binding domain of this upstream regulator of BAX gene transcription are responsible for differences in BAX protein expression. As previously observed, BAX was differentially expressed in the breast cancer samples, but no mutations in the coding sequence of the BAX gene were found besides a polymorphism in exon 6 at the position 552 (G->A) and additional intronic polymorphisms. In contrast, we identified 16 of 68 (23.5%) tumors to bear mutations in the p53 gene. In the subset of BAX-expressing tumors, the mutational inactivation of p53 did result in a reduced BAX protein expression (Fisher exact test, p = 0. 047). Nevertheless, we identified a subset of BAX-negative tumors lacking BAX or p53 mutations. Thus, additional, not yet identified regulators, apart from p53, appear to be involved in the regulation of BAX protein expression.

The London Depression Intervention Trial. Randomised controlled trial of antidepressants v. couple therapy in the treatment and maintenance of people with depression living with a partner: clinical outcome and costs

BACKGROUND

Relapse of depression is associated with a criticising attitude of the patient's partner.

AIMS

To compare the relative efficacy and cost of couple therapy and antidepressant drugs for the treatment and maintenance of people with depression living with a critical partner.

METHOD

A randomised controlled trial of antidepressant drugs v. couple therapy. The subjects were 77 people meeting criteria for depression living with a critical partner.

RESULTS

Drop-outs were 56.8% [corrected] from drug treatment and 15% from couple therapy. Subjects' depression improved in both groups, but couple therapy showed a significant advantage, according to the Beck Depression Inventory, both at the end of treatment and after a second year off treatment. Adding the costs of the interventions to the costs of services used showed there was no appreciable difference between the two treatments.

CONCLUSIONS

For this group couple therapy is much more acceptable than antidepressant drugs and is at least as efficacious, if not more so, both in the treatment and maintenance phases. It is no more expensive overall.

Cloning and characterization of the mammalian brain-specific, Mg2+-dependent neutral sphingomyelinase

The enzymatic breakdown of sphingomyelin by sphingomyelinases is considered the major source of the second messenger ceramide. Studies on the contribution of the various described acidic and neutral sphingomyelinases to the signaling pool of ceramide have been hampered by the lack of molecular data on the neutral sphingomyelinases (nSMases). We recently identified a mammalian nSMase, an integral membrane protein with remote similarity to bacterial sphingomyelinases. However, its ubiquitous expression pattern is in contrast to previous findings that sphingomyelinase activity is found mainly in brain tissues. By using an improved database search method, combined with phylogenetic analysis, we identified a second mammalian nSMase (nSMase2) with predominant expression in the brain. The sphingomyelinase activity of nSMase2 has a neutral pH optimum, depends on Mg(2+) ions, and is activated by unsaturated fatty acids and phosphatidylserine. Immunofluorescence reveals a neuron-specific punctate perinuclear staining, which colocalizes with a Golgi marker in a number of cell lines. The likely identity of nSMase2 with cca1, a rat protein involved in contact inhibition of 3Y1 fibroblasts, suggests a role for this enzyme in cell cycle arrest. Both mammalian nSMases are members of a superfamily of Mg(2+)-dependent phosphohydrolases, which also contains nucleases, inositol phosphatases, and bacterial toxins.

Survival and dominant transmission of "lethal" platyspondylic dwarfism of the "West coast" types

Torrance, San Diego, and Luton types ("West coast" types) of neonatal platyspondylic short-limbed dwarfism are suspected to be caused by dominant mutations that are obligatorily lethal. We report on an affected mother, who passed the disease to her daughter, confirming dominant disease transmission. Survival of the mother indicates a wider phenotypic spectrum.

An investigation of shame and guilt in a depressed sample

A self-report measure of proneness to shame and guilt was administered to 86 patients with moderate to severe depression, with the prediction that there would be a positive correlation of shame with severity of depression. Contrary to other, non-clinical studies, we found that guilt but not shame was associated with levels of depression. Shame-proneness demonstrated a unique association with a stable attributional style for negative outcomes, global negative self-evaluation, submissive behaviour and internalized anger. Contrary to prediction, no relationship was found between shame- or guilt-proneness and a reported history of childhood sexual abuse.

A descriptive analysis of factors contributing to binge eating

This study was designed to examine temporally proximal and remote antecedents as well as immediate and delayed consequences of binge eating behavior. Participants included 16 undergraduate females who reported engaging in binge eating at least two times per week and experiencing a sense of lack of control during binge eating episodes on the Questionnaire of Eating and Weight Patterns. Results indicated that the most frequent proximal antecedents to binge eating were negative emotions such as feeling depressed, angry, empty, hopeless, worried, or dissatisfied. The most frequent consequences of binge eating included relief from negative feelings and thoughts and decrease in hunger or craving. The results of this study suggest that the function of binge eating can be identified through assessment of antecedents and consequences with real time recording and retrospective reports. Treatment implications are discussed.

Analysis of the p53/BAX pathway in colorectal cancer: low BAX is a negative prognostic factor in patients with resected liver metastases

PURPOSE

To determine the prognostic value of the central downstream apoptosis effector BAX in relation to its upstream regulator p53 in R0-resected hepatic metastases of colorectal cancer.

PATIENTS AND METHODS

Retrospective analysis of 41 patients who underwent potentially curative resection of liver metastases from colarectal cancer was performed. Tumor DNA was screened for p53 mutations by single-stranded conformational polymorphism polymerase chain reaction and for BAX frameshift mutations by fragment length analysis. Protein expression of BAX, p21, and p53 was investigated by immunohistochemistry.

RESULTS

Overall median survival was 40.2 months. Tumors with BAX frameshift mutations were considered microsatellite mutator phenotype-positive and were excluded from further prognostic analyses. Patients with high BAX protein expression had a median survival of 53.6 months compared with 35.4 months for patients with low BAX expression (P < .05). The negative prognostic value of low BAX expression was more evident in those patients with wild-type p53 (median survival, 54.0 v 23.3 months for BAX-negative tumors; P < .01). Low BAX expression was an independent negative prognostic marker in multivariate regression analysis for all patients independent of the p53 status (relative risk, 3.03, P = .03), especially for p53 wild-type tumors (relative risk, 8.21; P = .0095).

CONCLUSION

We conclude that low BAX expression is an independent negative prognostic marker in patients with hepatic metastases of colorectal cancer. The best survival was seen in patients with an intact p53-to-BAX pathway; ie, wild-type p53- and BAX-positive tumors. Thus, analysis of apoptosis signaling pathways (here, p53 in concert with its downstream death effector, BAX) might yield more prognostic power in future studies as compared with analysis of single genes such as p53 alone.

Non-compliance following renal transplantation in children and adolescents

Reported frequencies of non-compliance in children with end-stage renal disease range from 8% to 70% with a mean around 40%. Sequelae amount to momentous emotional and financial burdens, including the loss of 7% of transplanted organs. Reasons for non-compliance have too often been attributed selectively to the patients (e.g., emotional, mental, social, or communication problems). Compared with general compliance research, this selective attribution appears to be too simplistic. Selective attribution neglects the patients' experiences within the context of disease and treatment and prevents open communication about non-compliance. Research on personal reasons for non-compliance is scarce. In psychological interviews, a third of our 85 patients with end-stage renal disease (34 boys, 51 girls, mean age 12.7 years, range 7.4-19.3 years) communicated psychologically meaningful reasons for non-compliance, frequently related to interrelational and systemic treatment conditions. Patients indirectly asked for more communication about their subjective reasons for non-compliance.

Ex vivo breast cancer cell purging by adenovirus-mediated cytosine deaminase gene transfer and short-term incubation with 5-fluorocytosine completely prevents tumor growth after transplantation

Peripheral blood progenitor harvests of breast cancer patients are contaminated with tumor cells, suggesting a potential role for these cells in the relapse after high-dose chemotherapy. Whereas physical purging methods do not eliminate contaminating tumor cells completely, pharmacological purging, although highly efficient, is hampered by a strong nonspecific toxicity toward hematopoietic progenitor cells. Taking advantage of the high efficiency of adenovirus-mediated gene transfer to epithelial cells, we selectively loaded breast cancer cells in vitro with a cytotoxic drug by gene transfer of the prodrug-converting enzyme cytosine deaminase (AdCMV.CD) and 5-fluorocytosine (5-FC). Despite the low dose of vector administered, limited exposure to 5-FC, and transplantation only of viable tumor cells into SCID mice, all animals that received cells treated in vitro with AdCMV.CD plus 5-FC were completely free of tumor development. These data show that the selective loading of tumor cells with AdCMV.CD/5-FC might be useful for purging of autografts.

Deletion mapping on chromosome 10p and definition of a critical region for the second DiGeorge syndrome locus (DGS2)

DiGeorge syndrome (DGS) is a developmental field defect, characterised by absent/hypoplastic thymus and parathyroid, and conotruncal heart defects, with haploinsufficiency loci at 22q (DGS1) and 10p (DGS2). We performed fluorescence in situ hybridisations (FISH) and polymerase chain reaction (PCR) analyses in 12 patients with 10p deletions, nine of them with features of DGS, and in a familial translocation 10p;14q associated with midline defects. The critical DGS2 region is defined by two DGS patients, and maps within a 1 cM interval including D10S547 and D10S585. The other seven DGS patients are hemizygous for both loci. The breakpoint of the reciprocal translocation 10p;14q maps at a distance of at least 12 cM distal to the critical DGS2 region. Interstitial and terminal deletions described are in the range of 10-50 cM and enable the tentative mapping of loci for ptosis and hearing loss, features which are not part of the DGS clinical spectrum.

Role of alveolar macrophages in rapid elimination of adenovirus vectors administered to the epithelial surface of the respiratory tract

To evaluate the hypothesis that innate immune mechanisms play a major role in eliminating adenovirus (Ad) vectors from the lung, the fate of adenoviral genome of an Ad vector was quantified in the first 24 h after intratracheal administration of an Ad vector coding for beta-galactosidase (beta gal) to mice. Southern analysis with an Ad specific probe showed that 70% of the Ad genome was lost within 24 h, in both immunocompetent and immunodeficient animals. When alveolar macrophages were eliminated by administration of liposomes containing dichloromethylene-biphosphanate, subsequent administration of Ad vector was associated with a 100%+/-8% increase in lung Ad DNA and 96%+/-9% rise in beta gal expression at 24 h compared to control animals. In vitro infection of mouse, rat, and human alveolar macrophages with an Ad vector resulted in 65% loss of vector genome within 24 h, whereas the vector genome was stable in lung epithelial cell lines. PCR in situ hybridization demonstrated that the Ad vector genome persisted A549 lung epithelial cell in vitro but not in alveolar macrophages. Finally, alveolar macrophages recovered from the mouse lung 30 min following intratracheal administration of an Ad vector showed large amounts of vector genome, whereas much less was evident in alveolar macrophages recovered after 24 h. These observations demonstrate that alveolar macrophages play an important role in elimination of Ad vectors from the lung and suggest that strategies to transiently suppress this major innate immune defense system might be rewarding in enhancing the efficiency Ad vectors for lung gene therapy.