Abstract
Tumors frequently induce the multifunctional cytokine IL-6, which has been linked to several paraneoplastic syndromes, most notably cachexia. IL-6 stimulates osteoclast formation, causes mild hypercalcemia, and is produced by bone cells in vitro upon exposure to systemic hormones. Since IL-6 is produced together with parathyroid hormone-related protein (PTH-rP) in some patients with cancer, we tested the hypothesis that production of IL-6 potentiates the effects of PTH-rP on Ca2+ homeostasis and osteoclastic bone resorption and examined potential mechanisms for these interactions in vivo. Chinese hamster ovarian (CHO) cells stably transfected with cDNAs for IL-6 (CHO/IL-6) and PTH-rP sense (CHO/PTH-rP) or antisense (CHO/PTH-rP AS) were inoculated intramuscularly into nude mice. Experimental groups included CHO/IL-6 plus CHO/PTH-rP; CHO/IL-6 plus CHO/PTH-rP AS; CHO/IL-6 alone; and CHO/PTH-rP alone. Blood ionized Ca2+ was measured on days 0, 7, 10, 12, and 13. Three different developmental stages in the osteoclast lineage were examined at day 13: the early multipotential precursor, granulocyte macrophage colony-forming units (CFU-GM); more mature mononuclear osteoclast precursors, assessed by their capacity to form tartrate-resistant acid phosphatase-positive multinucleated cells in marrow cultures; and mature osteoclasts, assessed by histomorphometry. IL-6 increased CFU-GM but not bone resorption or Ca2+. In contrast, PTH-rP induced hypercalcemia and bone resorption and increased multinucleated osteoclasts and more mature precursors cells, but not CFU-GM. However, mice treated with both IL-6 and PTH-rP had very marked hypercalcemia and osteoclastosis as well as an increase in the number of both CFU-GM and mature osteoclast precursors. These data demonstrate that IL-6 enhances PTH-rP-mediated hypercalcemia and bone resorption, most likely by increasing the pool of early osteoclast precursors that in turn can differentiate to mature osteoclasts. We conclude that IL-6 stimulatory effects on osteoclast precursors may enhance the effects of other bone resorption factors that act at later stages in the osteoclast lineage.
Full text
PDF






Images in this article
Selected References
These references are in PubMed. This may not be the complete list of references from this article.
- Black K., Garrett I. R., Mundy G. R. Chinese hamster ovarian cells transfected with the murine interleukin-6 gene cause hypercalcemia as well as cachexia, leukocytosis and thrombocytosis in tumor-bearing nude mice. Endocrinology. 1991 May;128(5):2657–2659. doi: 10.1210/endo-128-5-2657. [DOI] [PubMed] [Google Scholar]
- Budayr A. A., Nissenson R. A., Klein R. F., Pun K. K., Clark O. H., Diep D., Arnaud C. D., Strewler G. J. Increased serum levels of a parathyroid hormone-like protein in malignancy-associated hypercalcemia. Ann Intern Med. 1989 Nov 15;111(10):807–812. doi: 10.7326/0003-4819-111-10-807. [DOI] [PubMed] [Google Scholar]
- Chen L., Mory Y., Zilberstein A., Revel M. Growth inhibition of human breast carcinoma and leukemia/lymphoma cell lines by recombinant interferon-beta 2. Proc Natl Acad Sci U S A. 1988 Nov;85(21):8037–8041. doi: 10.1073/pnas.85.21.8037. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Guise T. A., Chirgwin J. M., Favarato G., Boyce B. F., Mundy G. R. Chinese hamster ovarian cells transfected with human parathyroid hormone-related protein cDNA cause hypercalcemia in nude mice. Lab Invest. 1992 Oct;67(4):477–485. [PubMed] [Google Scholar]
- Houssiau F. A., Devogelaer J. P., Van Damme J., de Deuxchaisnes C. N., Van Snick J. Interleukin-6 in synovial fluid and serum of patients with rheumatoid arthritis and other inflammatory arthritides. Arthritis Rheum. 1988 Jun;31(6):784–788. doi: 10.1002/art.1780310614. [DOI] [PubMed] [Google Scholar]
- Ishimi Y., Miyaura C., Jin C. H., Akatsu T., Abe E., Nakamura Y., Yamaguchi A., Yoshiki S., Matsuda T., Hirano T. IL-6 is produced by osteoblasts and induces bone resorption. J Immunol. 1990 Nov 15;145(10):3297–3303. [PubMed] [Google Scholar]
- Jilka R. L., Hangoc G., Girasole G., Passeri G., Williams D. C., Abrams J. S., Boyce B., Broxmeyer H., Manolagas S. C. Increased osteoclast development after estrogen loss: mediation by interleukin-6. Science. 1992 Jul 3;257(5066):88–91. doi: 10.1126/science.1621100. [DOI] [PubMed] [Google Scholar]
- Löwik C. W., van der Pluijm G., Bloys H., Hoekman K., Bijvoet O. L., Aarden L. A., Papapoulos S. E. Parathyroid hormone (PTH) and PTH-like protein (PLP) stimulate interleukin-6 production by osteogenic cells: a possible role of interleukin-6 in osteoclastogenesis. Biochem Biophys Res Commun. 1989 Aug 15;162(3):1546–1552. doi: 10.1016/0006-291x(89)90851-6. [DOI] [PubMed] [Google Scholar]
- Miki S., Iwano M., Miki Y., Yamamoto M., Tang B., Yokokawa K., Sonoda T., Hirano T., Kishimoto T. Interleukin-6 (IL-6) functions as an in vitro autocrine growth factor in renal cell carcinomas. FEBS Lett. 1989 Jul 3;250(2):607–610. doi: 10.1016/0014-5793(89)80805-1. [DOI] [PubMed] [Google Scholar]
- Mulé J. J., McIntosh J. K., Jablons D. M., Rosenberg S. A. Antitumor activity of recombinant interleukin 6 in mice. J Exp Med. 1990 Mar 1;171(3):629–636. doi: 10.1084/jem.171.3.629. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Pandian M. R., Morgan C. H., Carlton E., Segre G. V. Modified immunoradiometric assay of parathyroid hormone-related protein: clinical application in the differential diagnosis of hypercalcemia. Clin Chem. 1992 Feb;38(2):282–288. [PubMed] [Google Scholar]
- Roodman G. D. Interleukin-6: an osteotropic factor? J Bone Miner Res. 1992 May;7(5):475–478. doi: 10.1002/jbmr.5650070502. [DOI] [PubMed] [Google Scholar]
- Roodman G. D., Kurihara N., Ohsaki Y., Kukita A., Hosking D., Demulder A., Smith J. F., Singer F. R. Interleukin 6. A potential autocrine/paracrine factor in Paget's disease of bone. J Clin Invest. 1992 Jan;89(1):46–52. doi: 10.1172/JCI115584. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Serve H., Steinhauser G., Oberberg D., Flegel W. A., Northoff H., Berdel W. E. Studies on the interaction between interleukin 6 and human malignant nonhematopoietic cell lines. Cancer Res. 1991 Aug 1;51(15):3862–3866. [PubMed] [Google Scholar]
- Strassmann G., Fong M., Kenney J. S., Jacob C. O. Evidence for the involvement of interleukin 6 in experimental cancer cachexia. J Clin Invest. 1992 May;89(5):1681–1684. doi: 10.1172/JCI115767. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Suda T., Yamaguchi Y., Suda J., Miura Y., Okano A., Akiyama Y. Effect of interleukin 6 (IL-6) on the differentiation and proliferation of murine and human hemopoietic progenitors. Exp Hematol. 1988 Dec;16(11):891–895. [PubMed] [Google Scholar]
- Yoneda T., Nakai M., Moriyama K., Scott L., Ida N., Kunitomo T., Mundy G. R. Neutralizing antibodies to human interleukin 6 reverse hypercalcemia associated with a human squamous carcinoma. Cancer Res. 1993 Feb 15;53(4):737–740. [PubMed] [Google Scholar]
- van Oers M. H., van Zaanen H. C., Lokhorst H. M. Interleukin-6, a new target for therapy in multiple myeloma? Ann Hematol. 1993 May;66(5):219–223. doi: 10.1007/BF01738469. [DOI] [PubMed] [Google Scholar]


