Glutathione S-transferase-pi gene expression and platinum drug exposure in human lung cancer

We examined the association between the gene expression levels of glutathione S-transferase-pi (GST-pi) and platinum drug exposure in human lung cancer. First we monitored GST-pi gene expression levels in two lung cancer cell lines and in peripheral mononuclear cells of ten previously untreated lung cancer patients after platinum drug exposure. Next we examined GST-pi gene expression levels in 40 lung cancer autopsy specimens. The GST-pi gene expression levels were assessed by the quantitative reverse transcription-polymerase chain reaction or Northern blot analysis. The GST-pi gene expression was not induced by platinum drugs either in vitro and in vivo within 24 h of exposure. In contrast, GST-pi gene expression levels in lung cancer tissues of patients who had been exposed to platinum drugs at least 1 month before death were significantly higher than that in those of patients who had not been exposed. These results suggest that GST-pi gene expression is associated with chronic exposure to platinum drugs in lung cancer and/or the stress response to xenobiotics.