Anti-DKK1 mAb (BHQ880) as a potential therapeutic agent for multiple myeloma

Abstract

Decreased activity of osteoblasts (OBs) contributes to osteolytic lesions in multiple myeloma (MM). IntroductionA cardinal clinical feature of multiple myeloma (MM) is the presence of osteolytic bone lesions. Myeloma cells disrupt the delicate balance between bone formation and bone resorption. 1,2 Various clinical observations 3 and experimental studies 4,5 have linked the level of MM bone disease with disease burden. Increased osteoclastic activity and its molecular basis have long been considered a primary pathogenic event in MM bone disease. However, a molecular basis for the well recognized lack of osteoblast (OB) function, specifically DKK-1, in the MM bone disease has only recently been described. 6,7 Canonical Wnt pathway plays an important role in controlling proliferation, differentiation, and survival of OB. [8][9][10][11] Previous studies have reported high expression levels of the canonical Wnt inhibitor DKK1 and osteolytic bone lesions in various tumor types including breast, 12,13 neuroblastoma, 14 esophageal, and lung cancer, 15 and conversely enhanced OB activity and osteoblastic bone lesions associated with decreased DKK1 levels in prostate and colon cancers. [16][17][18] In MM, high serum DKK1 levels were correlated with focal bone lesions. 19 The DKK1 produced by MM cells can inhibit the differentiation of OB precursor cells 19 and bone formation in vitro 20 through a DKK1-mediated attenuation of Wnt3a-induced stabilization of ␤-catenin. 21 These findings confirm DKK1 as an important regulator of bone formation in the bone microenvironment. The importance of DKK1 secretion in diseases associated with bone destruction is reinforced by a recent study showing that DKK1 mediates the bone destructive effects of rheumatoid arthritis and that a neutralizing antibody to DKK1 could inhibit the bone destructive process in that disease. 22 There is also emerging evidence that the cellular bone compartment affects MM cell growth and progression. This is supported by the observation that osteoclasts can support long-term survival and proliferation of primary MM cells, 23,24 and OB may impede MM cell growth. 7,25 Thus, targeting these cellular elements may also favorably affect disease control. Therefore, we have evaluated DKK1 as a therapeutic target in MM in the context of the bone marrow (BM) microenvironment, analyzing the effect of a human DKK1 neutralizing antibody (BHQ880). We show that this clinically applicable antibody increases OB function and number and also has anti-MM effect when evaluated in the presence of the BM milieu. Methods ReagentsBHQ880 is a phage-derived DKK1 neutralizing human immunoglobulin G1 (IgG1) antibody (provided by Novartis, Cambridge, MA). BHQ880 has a high affinity for and can neutralize both human DKK1 and murine DKK1. IgG1 isotype antibody was used as control. CellsBone marrow mononuclear cells (BMMNCs) and primary MM cells were isolated using Ficoll-Hypaque density gradient sedimentation from BM Submitted November 25, 2008; accepted April 20, 2009. Prepublished online ...

Autocrine stimulation of osteoblast activity by Wnt5a in response to TNF-α in human mesenchymal stem cells

“…Since TNF-a seemed to increase the levels of other canonical Wnt proteins, we investigated the activation of the canonical Wnt signaling pathway with anti-Dkk1 antibodies. Stimulatory effects of anti-Dkk1 antibodies have recently been reported in mouse primary osteoblasts [17], and are consistent with the beneficial effects of anti-Dkk1 antibodies on bone formation in vivo [10,17,35,36]. In our experiments, blocking Dkk1 slightly increased TNAP expression in osteoblasts differentiating from human MSCs.…”

Bone Anabolic Agents for the Treatment of Multiple Myeloma

“…In vivo studies using both murine and humanized models of MM-bone disease confirmed the bone-anabolic properties of DKK1 antagonists, with increased bone formation, increased OB number and improvement of osteolytic lesions [31,33,34]. Importantly, two studies showed a significant reduction in tumor burden, mainly as an indirect effect via modification of the tumor microenvironment by DKK1 inhibition [31,33]. A clinical trial (NCT00741377) has been opened in 2008 to assess safety and tolerability as well as efficacy of the DKK1 inhibitor BHQ880 in combination with standard chemotherapy with or without bisphosphonates in relapsed or refractory MM patients.…”

“…BHQ880 and DKK1 Antagonists BHQ880 is a clinical grade neutralizing antibody against DKK1 (Novartis), which promotes OB differentiation by reversing the negative effects of MM cells on OB formation and inhibits IL-6 production by BMSC, thereby blocking tumor cells proliferation [33]. In vivo studies using both murine and humanized models of MM-bone disease confirmed the bone-anabolic properties of DKK1 antagonists, with increased bone formation, increased OB number and improvement of osteolytic lesions [31,33,34].…”

“…In addition, MMderived DKK1 inhibits OPG expression in OBs and upregulates RANKL secretion [18], therefore stimulating osteoclastogenesis. Neutralizing antibodies against DKK1 promote OB differentiation [30] and limit MM cell proliferation when co-cultured with BMSC [33]. In several in-vivo models of MM bone disease, DKK1 inhibition prevents tumor-induced bone destruction, increases trabecular bone formation in both bones bearing MM cells and uninvolved bones, and reduces tumor burden [31,33,34].…”

“…Low dose bortezomib (0.7 mg/m2) will Increases bone formation markers, decreases pain. Decreases tumor burden BHQ880 [33] Neutralizing anti-DKK1 antibody Increases bone volume and OBn NA Decreases tumor burden MLN3897 [64] Small molecule CCR1 antagonists Trend for increase in osteocalcin expression NA Decreases OCn and tumor burden Teriparatide [109] Recombinant parathyroid hormone Increases BMD NA Decreases tumor burden AMG775…”