Heat shock protein 27 was up-regulated in cisplatin resistant human ovarian tumor cell line and associated with the cisplatin resistance.

To understand the molecular basis for failure of cisplatin (CDDP) based chemotherapy, we compared gene expressions between CDDP sensitive and resistant ovarian tumor cell line, 2008 and 2008/C13*5.25, by mRNA differential display. We detected both up-regulated and down-regulated bands in the resistant cell and found some of them to be positive on Northern blotting. DNA sequencing revealed one to be mitochondrial heat shock protein 75. We found that HSP27 and HSP70 were also up-regulated in the resistant cell by Western blotting. Further, transient transfection with the HSP27 sense gene made the sensitive cell more resistant, while transient transfection with the antisense gene made it more sensitive.