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Alveolar macrophages play an important role in chronic obstructive pulmonary disease via production of matrix metalloproteinases (MMPs) and cathepsins as well as their inhibitors, tissue inhibitors of metalloproteinases and cystatin C. We hypothesised that expression levels of these molecules by alveolar macrophages at baseline and after stimulation would be influenced by genotype and associated with chronic obstructive pulmonary disease phenotypes. Quantitative PCR and ELISAs/gelatine zymography were used to investigate expression levels of mRNA and protein, respectively. The relationships of expression with genotype, pulmonary function and emphysema were analysed. The results showed that basal expression level of MMP12 mRNA was inversely related to the diffusing capacity of the lung for carbon monoxide/alveolar volume and to forced expiratory volume in 1 s/forced vital capacity after correction for multiple comparisons. The expression level of MMP12 protein stimulated with lipopolysaccharide was also inversely related to the diffusing capacity of the lung for carbon monoxide/alveolar volume and was positively related to the extent of emphysema. The basal expression of MMP1 mRNA was positively correlated with the extent of emphysema. Cathepsin L protein level was positively associated with forced expiratory volume in 1 s % predicted. We conclude that increased MMP12 and MMP1 expression may play a role in the pathogenesis of emphysema. Cathepsin L and MMP9 may be involved in the development of airflow limitation.

To the Editors: In a recent issue of the European Respiratory Journal , Chappell et al. 1 clearly demonstrated that the lack of association with any of the tumour necrosis factor (TNF)-α single nucleotide polymorphisms or haplotypes makes it highly unlikely that polymorphisms in this gene play a major role in susceptibility to chronic obstructive pulmonary disease (COPD). Their sample sizes were sufficient to elucidate association of TNF-α gene variations with susceptibility to COPD. However, they neglected the effect of ethnicity differences in genetic susceptibility to COPD. The frequency of the TNF-α-308*2 allele in Caucasian control populations (10–17%) is higher than that in Asians (0–8%) 1–10. Genetic susceptibility …

p27Kip1 is a cyclin-dependent kinase inhibitor, it negatively regulates G1 progression and is reported to modulate apoptosis. Phosphorylation of this protein is thought to regulate its intracellular localisation and affect its stability. The aim of this study was to regulate p27Kip1 expression levels, and to examine how this protein affects cell cycle status and modulates viability in A549 lung adenocarcinoma cells. In addition, the association between phosphorylation status of p27Kip1 and its intracellular localisation was investigated, using expression vectors with cDNA of p27Kip1 or mutants in which the phosphorylation sites had been mutated. Although overexpression of p27Kip1 reduced cell cycle progression, its removal did not change cell cycle status. Modest induction of p27Kip1 rescued adenovector-induced apoptosis and its removal with short interfering RNA increased spontaneous cell death. It was also observed that p27Kip1 localised mainly in the cytoplasm, and forced expression of p27Kip1 cDNA with the substitution of serine (S) 10, threonine (T) 157 and T198 to glutamate (phosphor-mimetic) induced its cytoplasmic localisation. In conclusion, p27Kip1, when expressed physiologically, exists mainly in the cytoplasm, has little effect on cell cycle status and contributes viability in A549 lung adenocarcinoma cells. It was also surmised that intracellular localisation of p27Kip1 dominates its function and that its localisation was partly determined by its phosphorylation.

To the Editor: In a recent issue of the European Respiratory Journal , Barcelo et al. 1 reported results on the plasma angiotensin converting enzyme (ACE) activity and the distribution of an insertion (I)/deletion (D) polymorphism of the ACE gene both in obstructive sleep apnoea syndrome (OSAS) patients and in healthy controls. They found that ACE activity was higher in OSAS patients (53.9±2.5 international units (IU)·L−1) than in healthy controls (42.4±3.1 IU·L−1, p

Although replication-defective adenoviruses (Ads) are used as vectors for delivering therapeutic genes to cancer cells, various effects of the viruses on the proliferation of lung cancer cells have been reported. Experiments were carried out to determine whether or not E1-deleted Ad vectors (Ad5-CMV-lacZ) affected cell kinetics in two different types of lung cancer cell line in vitro. A dose-dependent relationship was measured between the vector multiplicity of infection (MOI) and the efficiency of lacZ gene transfer to lung cancer cells. The growth curves of vector-infected cells were shifted to the right compared with those of vehicle-exposed cells in a vector MOI-dependent fashion. The slowed cell proliferation resulted from both increased cell death and slower cell cycle progression of the vector-infected cells. The morphology of vector-exposed cells revealed apoptotic features including nuclear condensation and fragmented nuclei. These results indicate that using a higher vector MOI causes a higher gene transfer rate, but may induce apoptosis of infected cells. Although vector-induced apoptosis may be advantageous in inhibiting tumour growth, apoptosis of vector-infected cells may also reduce transgene expression in cancer cells. Minimization of the induction of apoptosis of vector-infected cells is important for the prolongation of the transduction efficiency of Ad vectors.