p53 promotes adenoviral replication and increases late viral gene expression.

The tumor suppressor protein, p53, plays a critical role in viro-oncology. However, the role of p53 in adenoviral replication is still poorly understood. In this paper, we have explored further the effect of p53 on adenoviral replicative lysis. Using well-characterized cells expressing a functional p53 (A549, K1neo, RKO) and isogenic derivatives that do not (K1scx, RKOp53.13), we show that virus replication, late virus protein expression and both wtAd5 and ONYX-015 virus-induced cell death are impaired in cells deficient in functional p53. Conversely, by transfecting p53 into these and other cells (IIICF/c, HeLa), we increase late virus protein expression and virus yield. We also show, using reporter assays in IIICF/c, HeLa and K1scx cells, that p53 can cooperate with E1a to enhance transcription from the major late promoter of the virus. Late viral protein production is enhanced by exogenous p53. Taken together, our data suggest that functional p53 can promote the adenovirus (Ad) lytic cycle. These results have implications for the use of Ad mutants that are defective in p53 degradation, such as ONYX-015, as agents for the treatment of cancers.

Drug metabolism genotypes and their association with adverse drug reactions in selected populations: a pilot study of methodology.

Aims-(1) To undertake a pilot population study of the investigation of pharmacogenetic factors that may lead to adverse drug reactions (ADRs). (2) To investigate whether a population of patients taking fluoxetine, moclobemide or omeprazole reported to the New Zealand (NZ) Intensive Medicines Monitoring Programme (IMMP) with ADRs, have a higher frequency of CYP2D6 and CYP2C19 poor metabolizer (PM) genotypes than a reference population. (3) To determine the frequency of CYP2C19 alleles in the NZ Caucasian population.Methods-150 patients who had been notified to the NZ IMMP as experiencing an adverse event after being prescribed fluoxetine, moclobemide or omeprazole (50 on each) were approached by letter and asked if they would consent to take part. Of these, 31 patients and 56 subjects from a population of blood donors were genotyped for common CYP2D6 and CYP2C19 alleles.Results and conclusions-At either loci the distributions of genotypes were not significantly different in the IMMP patients compared with the reference population or with other reported studies. In this small study CYP2D6 or CYP2C19 PM genotypes are not overrepresented in selected patients with adverse reactions. Population studies involving sampling of blood for genotyping are feasible in the general population. Copyright (c) 2000 John Wiley & Sons, Ltd.

Familial overexpression of beta antithrombin caused by an Asn135Thr substitution.

We have investigated the basis of antithrombin deficiency in an asymptomatic individual (and family) with borderline levels (approximately 70% antigen and activity) of antithrombin. Direct sequencing of amplified DNA showed a mutation in codon 135, AAC to ACC, predicting a heterozygous Asn135Thr substitution. This substitution alters the predicted consensus sequence for glycosylation, Asn-X-Ser, adjacent to the heparin interaction site of antithrombin. The antithrombin isolated from plasma of the proband by heparin-Sepharose chromatography contained amounts of beta antithrombin (the very high affinity fraction) greatly increased (approximately 20% to 30% of total) above the trace levels found in normals. Expression of the residue 135 variant in both a cell-free system and COS-7 cells confirmed altered glycosylation arising as a consequence of the mutation. Wild-type and variant protein were translated and exported from COS-7 cells with apparently equal efficiency, in contrast to the reduced level of variant observed in plasma of the affected individual. This case represents a novel cause of antithrombin deficiency, removal of glycosylation concensus sequence, and highlights the potentially important role of beta antithrombin in regulating coagulation.