PRODUCTION AND RESPONSE OF HUMAN PROSTATE-CANCER CELL-LINES TO GRANULOCYTE MACROPHAGE-COLONY-STIMULATING FACTOR

Prostate cancer selectively metastasises to skeletal sites, where it n ormally produces osteoblastic lesions. This study investigated whether haematopoietic growth factors known to be present in the bone environ ment could be involved in the survival and proliferation of prostate s keletal metastases. To evaluate this hypothesis we investigated the ef fects of recombinant granulocyte/macrophage colony-stimulating factor (rGM-CSF), recombinant granulocyte colony-stimulating factor (rG-CSF), recombinant erythropoietin (rEPO) and recombinant interleukin-3 (rlL- 3) on the growth of 3 human prostate cancer cell lines. Two hormone-in sensitive cell lines, PC-3 and DU145, were significantly stimulated by rGM-CSF and rEPO in serum-free medium but their growth was unaffected by incubation with rlL-3 or rG-CSF. A hormone-sensitive cell line, LN CaP, was stimulated only by rGM-CSF. To investigate further the involv ement of GM-CSF in prostate cancer, the presence of GM-CSF protein in the 3 prostate cancer cell lines was examined by immunohistochemistry, and analysis of cell line conditioned media was carried out by ELISA and Western blotting. These techniques demonstrated that GM-CSF-like m aterial was produced by both DU145 and PC-3 cells but not by LNCaP. Th e results from ELISA found that media conditioned by DU145 and PC-3 ce lls contained 1.7 and 2.5 pg GM-CSF/mu g protein, respectively, wherea s no GM-CSF was detectable in the LNCaP conditioned media. Our results were also confirmed by Western blot analysis demonstrating one single band for DU145 and PC-3 conditioned media which co-migrated along wit h the standard rGM-CSF band. No bands were associated with the LNCaP c onditioned media. The presence of GM-CSF gene transcripts in DU145 and PC-3 cells was established by reverse transcription and polymerase ch ain reaction of total RNA. (C) 1994 Wiley-Liss, Inc.