Bisphosphonates regulate cell growth and gene expression in the UMR 106-01 clonal rat osteosarcoma cell line

Abstract

Despite significant improvements in patient survival and local disease control, 25% of patients with osteosarcoma develop metastases and the surgery for many extremity lesions still includes amputation. Thus, modalities that inhibit tumour growth and the metastatic cascade will have a significant impact on patient survival and potential for limb sparing surgery.Tumours induce bone destruction by cellular processes, such as osteoclast-mediated bone lysis. The importance of osteoclastmediated lysis has been demonstrated in other malignancies, where the development of osseous metastases has been shown to be mediated by soluble tumour-related osteoclast activating factors (Galasko, 1976). More recently, the induction of specific osteoclast recruiting factors in osteoblasts/stromal cells following contact with myeloma and breast cancer cells has been demonstrated (Chikatsu et al, 2000). Bisphosphonates have recognized efficacy in reducing bone destruction, pain and pathological fracture in a variety of lytic primary and metastatic diseases of the skeleton (Thiébaud et al, 1991;Coleman and Purohit, 1993;Shipman et al, 1997;Bloomfield, 1998;Diel et al, 1998). They have more recently been shown to inhibit establishment and growth of prostate cancer metastases, which are generally considered to be osteoblastic in their growth pattern (Adami, 1997). We proposed that, as with the intraosseous growth of prostate cancer, the local spread of osteosarcoma involves proteolytic and osteoclast-mediated bone destruction. The bisphosphonates may reduce bone destruction by uncoupling close regulation of osteoclast activity by osteoblast-like cells.The aims of our study were to examine the effects on the regulation of proliferation and apoptosis by bisphosphonate treatment of a clonal osteosarcoma cell line. Further, we assessed the expression of an osteoclast differentiating factor, receptor activator of NF-κβ (RANKL) (Yasuda et al, 1998b) and an osteoclastogenesis inhibitory factor, osteoprotegerin (OPG) (Simonet et al, 1997;Yasuda et al, 1998a). Finally, we investigated the effects on osteoblast-related gene expression by an aminobisphosphonate and a non-aminobisphosphonate. The use of a bisphosphonate from each group allows comparison of their relative potencies with the known effects on osteoclasts and bone resorption studies (Fleisch, 1993). MATERIALS AND METHODS Cell cultureUMR 106-01 cells derived from a 32 P-induced osteosarcoma in rats (Martin et al, 1976) were used. Cells were cultured in 75 cm 2 tissue culture flasks (Greiner Cellstar) in α-modified Minimal Essential Medium (α-MEM) containing hepes 4 g l Ϫ1 , sodium bicarbonate 1.95 g 6 Ϫ1 , gentamicin 80 mg 6 Ϫ1 , pH 7.4 and 10% fetal bovine serum (FBS), incubated at 37˚C and equilibrated in 5% CO 2 in air. Subcultures were performed using 0.0125% trypsin in 0.5 mM Na 2 EDTA in calcium and magnesium-free phosphate buffer (1 ϫ versene) to harvest the cells. Summary Local growth of osteosarcoma involves destruction of host bone by proteolytic mechanisms and/or host osteocl...

Zoledronic acid determines S-phase arrest but fails to induce apoptosis in cholangiocarcinoma cells

“…BPs are currently the most important class of inhibitors of osteoclast-mediated bone resorption and are used extensively for the treatment of skeletal diseases, such as Paget's disease, postmenopausal osteoporosis, and tumor-induced osteolysis [16,17]. The antiproliferative effect of pamidronate in human and rat osteosarcoma cells has recently been demonstrated in vitro [18,19]. BPs can be divided into two distinct pharmacological classes based on their molecular mechanisms of action [20].…”

Incadronate Amplifies Prostaglandin F2α-induced Vascular Endothelial Growth Factor Synthesis in Osteoblasts

“…Pamidronate and zoledronate have recently been shown to enhance the differentiation and boneforming activities of primary cultured human fetal osteoblasts (15). It has also been reported that pamidronate and clodronate increase the expression of mRNA for osteopontin and RANKL in UMR 106-01 rat osteoblastic osteosarcoma cells (16). Thus, it is currently speculated that the effects of bisphosphonates on bone metabolism are exerted through not only osteoclasts but also osteoblasts.…”

Onco-Nephrology

“…Because the IV bisphosphonates are excreted unchanged by the kidneys through glomerular filtration, their dosing must be adjusted for impaired renal function to avoid toxicity (35,36). Mechanistically, bisphosphonates decrease bone resorption through extracellular and intracellular mechanisms (37)(38)(39)(40)(41). In the extracellular space, bisphosphonates bind to calcium phosphate and stabilize the bone matrix, while intracellularly these agents inhibit osteoclast activity, in part through inhibition of the mevalonate pathway (37)(38)(39).…”

“…In the extracellular space, bisphosphonates bind to calcium phosphate and stabilize the bone matrix, while intracellularly these agents inhibit osteoclast activity, in part through inhibition of the mevalonate pathway (37)(38)(39). Furthermore, bisphosphonates impair cellular adenosine triphosphatedependent metabolic pathways, disrupt the osteoclast cytoskeleton, and induce apoptosis (40,41).…”