RESUMO
BACKGROUND: In recent years, the rapidly advancing field of low-temperature atmospheric pressure plasmas has shown considerable promise for future translational biomedical applications, including cancer therapy, through the generation of reactive oxygen and nitrogen species. METHOD: The cytopathic effect of low-temperature plasma was first verified in two commonly used prostate cell lines: BPH-1 and PC-3 cells. The study was then extended to analyse the effects in paired normal and tumour (Gleason grade 7) prostate epithelial cells cultured directly from patient tissue. Hydrogen peroxide (H2O2) and staurosporine were used as controls throughout. RESULTS: Low-temperature plasma (LTP) exposure resulted in high levels of DNA damage, a reduction in cell viability, and colony-forming ability. H2O2 formed in the culture medium was a likely facilitator of these effects. Necrosis and autophagy were recorded in primary cells, whereas cell lines exhibited apoptosis and necrosis. CONCLUSIONS: This study demonstrates that LTP treatment causes cytotoxic insult in primary prostate cells, leading to rapid necrotic cell death. It also highlights the need to study primary cultures in order to gain more realistic insight into patient response.
Assuntos
Apoptose/efeitos dos fármacos , Autofagia/efeitos dos fármacos , Temperatura Baixa , Dano ao DNA/efeitos dos fármacos , Células Epiteliais/patologia , Gases em Plasma/farmacologia , Próstata/patologia , Neoplasias da Próstata/patologia , Western Blotting , Células Cultivadas , Células Epiteliais/efeitos dos fármacos , Humanos , Peróxido de Hidrogênio/metabolismo , Masculino , Necrose , Próstata/efeitos dos fármacos , Neoplasias da Próstata/tratamento farmacológicoRESUMO
A coin-shaped ionisation chamber, orientated with its thin window facing away from the radiation source, was used to investigate the dose perturbations caused by the absence of back-scattering material near the exit surface of solid phantoms. Cobalt 60 and 4, 8 and 16 MV X-ray beams were used in the study. With no scattering material beyond the chamber window the ionisation was found to be as much as 17% less than the full scatter value. This was attributed to the absence of both back-scattered electrons and back-scattered photons. Full electron back-scattering could be restored by placing between 1.0 and 2.7 mm of unit density material beyond the chamber, depending on the primary beam energy. Under these circumstances the reduction in dose, now due to the absence of back-scattered photons only, was found to be small.