Expression of the chemokine receptor CCR1 promotes the dissemination of multiple myeloma plasma cells in vivo

Haematologica. 2021 Dec 1;106(12):3176-3187. doi: 10.3324/haematol.2020.253526.

Abstract

Multiple myeloma (MM) disease progression is dependent on the ability of MM plasma cells (PCs) to egress from the bone marrow (BM), enter the circulation and disseminate to distal BM sites. Expression of the chemokine CXCL12 by BM stromal cells is crucial for MM PC retention within the BM. However, the mechanisms which overcome CXCL12-mediated retention to enable dissemination are poorly understood. We have previously identified that treatment with the CCR1 ligand CCL3 inhibits the response to CXCL12 in MM cell lines, suggesting that CCL3/CCR1 signalling may enable egress of MM PC from the BM. Here, we demonstrated that CCR1 expression was an independent prognostic indicator in newly diagnosed MM patients. Furthermore, we showed that CCR1 is a crucial driver of dissemination in vivo, with CCR1 expression in the murine MM cell line 5TGM1 being associated with an increased incidence of bone and splenic disseminated tumours in C57BL/KaLwRij mice. Furthermore, we demonstrated that CCR1 knockout in the human myeloma cell line OPM2 resulted in a >95% reduction in circulating MM PC numbers and BM and splenic tumour dissemination following intratibial injection in NSG mice. Therapeutic targeting of CCR1 with the inhibitor CCX9588 significantly reduced OPM2 or RPMI-8226 dissemination in intratibial xenograft models. Collectively, our findings suggest a novel role for CCR1 as a critical driver of BM egress of MM PCs during tumour dissemination. Furthermore, these data suggest that CCR1 may represent a potential therapeutic target for the prevention of MM tumour dissemination.

MeSH terms

  • Animals
  • Cell Line, Tumor
  • Humans
  • Mice
  • Mice, Inbred C57BL
  • Multiple Myeloma* / drug therapy
  • Multiple Myeloma* / genetics
  • Plasma Cells
  • Receptors, CCR1 / genetics

Substances

  • CCR1 protein, human
  • Ccr1 protein, mouse
  • Receptors, CCR1

Grants and funding

Funding: This research was supported by grant 2002138 awarded through the 2020 Priority-driven Collaborative Cancer Research Scheme (PdCCRS), co-funded by Cancer Australia and Cure Cancer, and grant 1163245 awarded through the 2018 PdCCRS, co-funded by Cancer Australia, Cure Cancer, and Leukaemia Foundation of Australia, awarded to KV. The work was partially supported by a Hans-Jürgen and Marianne Ohff Research Grant from the University of Adelaide, awarded to MZ. MZ was supported by the Florey Medical Research Foundation Doctor Chun Chung Wong and Madam So Sau Lam Memorial Postgraduate Cancer Research Top-Up Scholarship and a Short-Term Research Grant from the German Academic Exchange Service (DAAD). VP was supported by a National Health & Medical Research Council Early Career Fellowship. KV and KMM were supported by Early Career Cancer Research Fellowships from the Cancer Council SA Beat Cancer Project on behalf of its donors and the State Government of South Australia through the Department of Health.