DETECTION OF AN INHIBITING ACTIVITY FOR OSTEOCLAST BONE-RESORPTION FROM HUMAN PROSTATIC-CANCER CELLS

An inhibiting activity for isolated osteoclasts and bone resorption wa s demonstrated in culture supernatants from androgen-independent, but not androgen-dependent, human prostatic cancer cell lines. It causes a dose-dependent osteoclast inhibition as quantified with a bone resorb ing pit formation assay. The constitutively released activity was dete rmined to be protein (>50 kDa) distinct from some of the known cytokin es in bone resorption. The activity does not affect osteoclast morphol ogy and viability. Time-lapse video microscopy revealed an osteoclast motility increase, disrupting their anchorage to the bone and resorbin g processes. The association of the activity with androgen-independent cancer cells that disrupt bone remodeling is discussed. (C) 1998 Else vier Science Ireland Ltd.