Lung resistance-related protein gene expression and drug sensitivity in human gastric and lung cancer cells.

Lung resistance-related protein (LRP) is the human major vault transporter protein and is suggested to confer anticancer drug resistance. We quantitated the level of LRP mRNA expression in 10 gastric and 14 lung cancer cell lines by RT-PCR, and examined the relationship between its level in these cells and their sensitivities to anticancer drugs. HT1080 fibrosarcoma cells were used as positive controls for LRP. LRP mRNA was expressed in all gastric and lung cancer lines, and its level in each cell type was less than two-fold that of HT1080 cells, except for two lung cancer lines. The correlation between the level of LRP mRNA expression and cisplatin sensitivity was significant in lung cancer lines (r = 0.762, P = 0.028), and borderline in gastric cancer lines (r = 0.631, P = 0.129). There was no correlation between the level of LRP mRNA expression and etoposide, doxorubicin, vincristine, or SN-38. Our results suggest that LRP is commonly expressed in gastric and lung cancers, and may confer their resistance to cisplatin.