Modification of chemo-radiosensitivity of a human lung cancer cell line by introduction of the glutathione S-transferase pi gene.

Recent studies have suggested that glutathione S-transferase pi (GST-pi) may play a role in determining tumor sensitivities to cytotoxic drugs. In order to better understand the role of this enzyme in chemo- and/or radioresistance of lung cancer cells, we examined whether introduction of GST-pi cDNA into a chemo- and radiosensitive lung cancer cell line altered its sensitivities to various chemotherapeutic agents and/or ionizing radiation, which are often used in the management of lung cancers. Modestly increased resistance of the GST-pi transfectants preferentially to sublethal damage caused by ionizing radiation as well as to adriamycin (ADM) was observed. In contrast, resistances to cisplatin (CDDP), etoposide (VP-16), irinotecan hydrochloride (CPT-11) and paclitaxel were virtually unaltered. These results suggest that GST-pi may not play a major role in chemo- and radioresistance of lung cancers, although it could afford selective and limited protection against ADM- and ionizing radiation-induced damage.