RESUMO
The growth of DU-145 human prostate carcinoma cells is reduced to 50% of control by 1 X 10(-6) M to 2 X 10(-6) M selenium and to 2% of control at 10(-4)M selenium. These cells show greater sensitivity to inhibition of growth or DNA synthesis by selenium than human W1-38 and HeLa cells and mouse mammary tumor cells. It has been shown that selenium inhibits carcinogenesis and reduces the incidence of chemical carcinogen and virus-induced tumors of a variety of organs in animals. Selenium may also inhibit the growth of certain tumor cells of non-human origin. To our knowledge, this is the first study on the effects of selenium on the growth of human tumor cells. From extrapolation, it is deduced that selenium serum levels in humans living in high selenium areas may be as high as 10(-6) M and could be effective in inhibiting the growth of tumor cells in vivo. These findings have implications in the prevention and intervention of prostate cancer in man.
Assuntos
Neoplasias da Próstata/metabolismo , Selênio/farmacologia , Animais , Divisão Celular/efeitos dos fármacos , Linhagem Celular , Relação Dose-Resposta a Droga , Feminino , Células HeLa/metabolismo , Humanos , Técnicas In Vitro , Masculino , Neoplasias Mamárias Experimentais/metabolismo , CamundongosRESUMO
Screening of cDNA libraries constructed in phage or plasmids with oligonucleotide probes has become one of the preferred cloning techniques with the least number of false positive failures. In this article we present our current protocols for designing the procedure to detect cDNA inserts and isolate them. We illustrate with primary screens for G protein subunits and membrane receptors.