The human CYP2A6 enzyme metabolizes certain drugs and pre-carcinogens and appears to be the most important enzyme for nicotine metabolism. At present, more than 10 different allelic variants are known that cause abolished or decreased enzyme activity. Genetic polymorphism in this gene might be of particular importance for an individual's need for nicotine and for susceptibility to lung and/or liver cancer. We have identified a new CYP2A6 allele (CYP2A6*12) which carries an unequal crossover between the CYP2A6 and CYP2A7 genes in intron 2. This results in a hybrid allele where the 5' regulatory region and exons 1-2 are of CYP2A7 origin and exons 3-9 are of CYP2A6 origin, resulting in 10 amino acid substitutions compared to the CYP2A6(*)1 allele. Phenotyping with the CYP2A6 substrate coumarin indicates that it causes reduced CYP2A6 activity in'vivo. Furthermore, when expressed in mammalian COS-1 cells, the enzyme variant catalyzed 7-hydroxylation of coumarin at a rate approximately 60% of that of the wild-type enzyme. The CYP2A6(*)12 allele was present at an allele frequency of 2.2% among Spaniards, but was absent in Chinese.

SummaryNeisseria gonorrhoeae is a human pathogen causing the sexually transmitted disease gonorrhoeae. The bacteria preferentially attach to and invade epithelial cells of the genital tract. As these cells previously have been shown to express the human cathelicidin LL-37, we wanted to investigate the role of LL-37 during N. gonorrhoeae infection. The cervical epithelial cell line ME180 was utilized and the expression of LL-37 was confirmed on both peptide and transcriptional levels. Moreover, LL-37 exhibited potent in vitro activity against N. gonorrhoeae. Interestingly, the transcript and peptide levels of LL-37 were downregulated during infection, according to quantitative real-time polymerase chain reaction (PCR) and immunocyto-chemistry. The downregulation was most prominent with pathogenic strains of Neisseria , while non-pathogenic strains such as Neisseria lactamica and Escherichia coli only exhibited moderate effects. Heat-killed N. gonorrhoeae had no impact on the downregulation, emphasizing the importance of live bacteria. The results in this study suggest that pathogenic Neisseria may gain a survival advantage in the female genital tract by downregulating LL-37 expression.

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SummaryNeisseria meningitidis and Neisseria gonorrhoeae colonize human mucosal surfaces and cause sepsis/ meningitis and gonorrhoea respectively. The first step in the infection process is pilus-mediated adhesion of the bacteria to epithelial cells, followed by host cell invasion. Adhesion of pathogenic Neisseria elicits multiple responses in host cells, including cellular signalling events, cytokine production and modulation of the eukaryotic cell surface. We used microarrays to assess the respective involvement of 375 human cytokine and adhesion related genes during adhesion of piliated and non-piliated N. gonorrhoeae , and piliated encapsulated N. meningitidis to the epithelial cell line ME-180. We identified 29 differentially regulated genes not previously reported to respond to neisserial infections, many of which encode membrane proteins. Selected genes were further analysed by semiquantitative RT-PCR, and protein expression was examined by flow cytometry. We found that N. gonorrhoeae elicited a different inflammatory response than N. meningitidis and we also demonstrated that early adhesion events are responsible for the induction of specific genes. Our data create a new platform for elucidating the interaction between pathogenic Neisseria and target cells.

Adrenocortical carcinoma (ACC) is a rare malignant disease with poor prognosis. The main pharmacological choice, o,p'-DDD (mitotane), produces severe adverse effects. Since o,p'-DDD is a chiral molecule and stereoisomers frequently possess different pharmacokinetic and/or pharmacodynamic properties, we isolated the two o,p'-DDD enantiomers, (R)-(+)-o,p'-DDD and (S)-(-)-o,p'-DDD, and determined their absolute structures. The effects of each enantiomer on cell viability and on cortisol and dehydroepiandrosterone (DHEA) secretion in the human adrenocortical cell line H295R were assessed. We also assayed the o,p'-DDD racemate and the m,p'- and p,p'-isomers. The results show small but statistically significant differences in activity of the o,p'-DDD enantiomers for all parameters tested. The three DDD isomers were equally potent in decreasing cell viability, but p,p'-DDD affected hormone secretion slightly less than the o,p'- and m,p'-isomers. The small chiral differences in direct effects on target cells alone do not warrant single enantiomer administration, but might reach importance in conjunction with possible stereochemical effects on pharmacokinetic processes in vivo.