A functional thrombin receptor (PAR1) is expressed on bone-derived prostate cancer cell lines

Objectives. To identify genes important in prostate cancer metastatic to bone. Bone-specific metastasis is a common feature of prostate cancer and a significant cause of morbidity. Methods. To identify factors involved in organ-specific metastasis, we used cDNA microarray analysis to compare a bone-derived cell line, VCaP, with a soft tissue-derived cell line, DuCaP. Both cell lines were derived from the same patient and spontaneously passaged. Results. Forty-five genes were differentially expressed, and only seven of these also had increased expression in VCaP compared with normal prostatic tissue. Of these, protease-activated receptor I (PAR I) was verified as having increased expression by reverse transcriptase-polymerase chain reaction and Northern blot analysis, as well as by immunohistochemistry. PAR1 expression in a panel of prostate cancer cell lines demonstrated increased expression in those cell lines derived from bone metastases. Alpha-thrombin stimulation of the VCaP cells produced a dose-dependent mobilization of intracellular calcium compared with DuCaP, suggesting that PAR I expressed on the VCaP prostate cancer cell line is functional. Conclusions. These data indicate that a functional PARI is expressed on prostate cancer cell lines. The prostate cancer cell lines expressing PARI appear to have an association with increased bone metastases. (C) 2002, Elsevier Science Inc.