Dual effects of macrophage inflammatory protein-1α on osteolysis and tumor burden in the murine 5TGM1 model of myeloma bone disease

Babatunde O. Oyajobi, Giovanni Franchin, Paul J. Williams, Donna Pulkrabek, Anjana Gupta, Steve Munoz, Barry Grubbs, Ming Zhao, Di Chen, Barbara Sherry, Gregory R. Mundy

Research output: Contribution to journalArticlepeer-review

175 Scopus citations

Abstract

Recent data have implicated macrophage inflammatory protein-1α (MIP-1α) in multiple myeloma (MM)-associated osteolysis. However, it is unclear whether the chemokine's effects are direct, to enhance osteolysis, or indirect and mediated through a reduction in tumor burden, or both. It is also unclear whether MIP-1α requires other factors such as receptor activator of nuclear factor-λB ligand (RANKL) for its effects on bone. In murine 5TGM1 (Radl) myeloma-bearing mice, administration of neutralizing anti-MIP-1α antibodies reduced tumor load assessed by monoclonal paraprotein titers, prevented splenomegaly, limited development of osteolytic lesions, and concomitantly reduced tumor growth in bone. To determine the effects of MIP-1α on bone in vivo, Chinese hamster ovary (CHO) cells secreting human MIP-1α (CHO/MIP-1α) were inoculated into athymic mice. Mice bearing intramuscular CHO/MIP-1α tumors developed lytic lesions at distant skeletal sites, which occurred earlier and were larger than those in mice with CHO/empty vector (EV) tumors. When experimental metastases were induced via intracardiac inoculation, mice bearing CHO/MIP-1α tumors developed hypercalcemia and significantly more osteolytic lesions than mice bearing CHO/EV tumors, with intramedullary CHO/MIP-1α tumors associated with significantly more tartrate-resistant acid phosphatase-positive (TRAP+) osteoclasts. Injection of recombinant MIP-1α over calvariae of normal mice evoked a striking increase in osteoclast formation, an effect dependent on RANK/RANKL signaling because MIP-1α had no effect in RANK-/- mice. Together, these results establish that MIP-1α is sufficient to induce MM-like destructive lesions in bone in vivo. Because, in the 5TGM1 model, blockade of osteoclastic resorption in other situations does not decrease tumor burden, we conclude that MIP-1α exerts a dual effect in myeloma, on osteoclasts, and tumor cells.

Original languageEnglish (US)
Pages (from-to)311-319
Number of pages9
JournalBlood
Volume102
Issue number1
DOIs
StatePublished - Jul 1 2003

ASJC Scopus subject areas

  • Biochemistry
  • Immunology
  • Hematology
  • Cell Biology

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