Decreased DNA repair capacity of UV-irradiated cells following interferon treatment.

The aim of this study was to examine the effect of interferons (IFNs) on the recovery of UV-damaged cells by means of measuring cell viability rates. The influence of the recombinant human interferons IFN-alpha, IFN-beta and IFN-gamma on the repair capacity of the UV-irradiated human cell lines WISH and HeLa was studied. The ability of cells to repair UV-induced damage was determined by the comet assay and both short- and long-term survival assays in proliferating cell cultures.

Influence of interferons on the repair of UV-damaged DNA.

The capacity for nucleotide excision repair of a normal (WISH) and three tumour (MCF-7, HeLa, Namalva) cell lines treated with human recombinant interferons (hrIFN-alpha and hrIFN-gamma) was compared by the host cell reactivation assay. The cells were transfected with in vitro UV-damaged plasmid DNA (pEGFP-N1). The repair capacity was determined by measuring the fluorescence intensity of the expressed marker protein in total cell lysates.

Spontaneous transfection of mammalian cells with plasmid DNA.

A simple method for spontaneous transfection into mammalian cells (both adherent and suspension in culture) with plasmid DNA is described. This method does not require any specific DNA carrier or technical device and can be applied for obtaining both transient and stably transfected cells. The efficiency of spontaneous transfection is slightly lower in comparison with that of the conventional calcium phosphate and lipofectin transfection methods and does not depend on the type of cell culture used.