Matrix Metalloproteinase (MMP)-13 Regulates Mammary Tumor–Induced Osteolysis by Activating MMP9 and Transforming Growth Factor-β Signaling at the Tumor-Bone Interface

Abstract

The tropism of breast cancer cells for bone and their tendency to induce an osteolytic phenotype are a result of interactions between breast cancer cells and stromal cells and are of paramount importance for bone metastasis. However, the underlying molecular mechanisms remain poorly understood. We hypothesize that tumor-stromal interaction alters gene expression in malignant tumor cells and stromal cells creating a unique expression signature that promotes osteolytic breast cancer bone metastasis and that inhibition of such interactions can be developed as targeted therapeutics. Microarray analysis was performed to investigate gene expression profiling at the tumor-bone (TB) interface versus the tumor alone area from syngenic mice injected with three different syngenic mammary tumor cell lines that differ in their metastatic potential. We identified matrix metalloproteinase 13 (MMP13), receptor activator of NF-κB ligand (RANKL), and integrins binding sialoprotein to be genes upregulated at the TB interface and validated. To determine the functional role of MMP13 in tumor-induced osteolysis, mice with Cl66 mammary tumors were treated with MMP13 antisense oligonucleotides (MMP13-ASO) or control scrambled oligonucleotides (control-ASO). Knockdown of MMP13 expression at the TB interface leads to significant reduction in bone destruction and in the number of activated osteoclasts at the TB interface. Further analysis to evaluate the mechanism of MMP13-dependent osteolytic bone metastasis revealed that MMP13-ASO treatment decreased active MMP9, RANKL levels, and transforming growth factor-β signaling at the TB interface. Together, our data indicate that upregulation of MMP13 at the TB interface is important in tumor-induced osteolysis and suggest that MMP13 is a potential therapeutic target for breast cancer bone metastasis. Cancer Res; 70(9); 3494-504.

Cross Talk among TGF- Signaling Pathways, Integrins, and the Extracellular Matrix

“…Conversely, Tgfb1 RGE/RGE ;Tgfb3 -/ -mice are all born with brain hemorrhage, the only phenotype in mice lacking avb8 that is not seen in mice lacking just TGF-b1 or TGF-b3 (Mu et al 2008). Thus, avb6 and Lyons et al (1990) and Flaumenhaft et al (1992); osteoclast data from Oursler (1994); MMP-13 data from Uchinami et al (2006) and Nannuru et al (2010); TSP1 data from Crawford et al (1998); Itgav 2/2 data from Bader et al (1998); avb6 data from Munger et al (1999); avb8, MT1-MMP data from Mu et al (2002); avb3, avb5 data from Wipff et al (2007); ROS data from Jobling et al (2006); shear force data from Ahamed et al (2008).…”

Bone marrow as a metastatic niche for disseminated tumor cells from solid tumors

“…45 When murine breast cancer cell line Cl66 cells are implanted into the subcutaneous spaces of mice near the calvarial bone, MMP-13, MMP-9, transforming growth factor (TGF)-b and phosphorylated Smad2 are expressed greater in the area where tumor interfaces with bone (TB interface), compared with areas of tumor alone. 46 It is in this TB interface where larger numbers of osteoclasts and bone resorption areas are found. 46 In addition, osteoclast number, osteolytic lesion frequency and MMP-13 expression at the TB interface are all significantly reduced when mice are treated with MMP-13 antisense oligonucleotides.…”

“…46 It is in this TB interface where larger numbers of osteoclasts and bone resorption areas are found. 46 In addition, osteoclast number, osteolytic lesion frequency and MMP-13 expression at the TB interface are all significantly reduced when mice are treated with MMP-13 antisense oligonucleotides. 46 Furthermore, MMP-13 antisense oligonucleotide treatments also impair the expression of MMP-9, TGF-b and phosphorylated Smad2 in the TB interface.…”

“…46 In addition, osteoclast number, osteolytic lesion frequency and MMP-13 expression at the TB interface are all significantly reduced when mice are treated with MMP-13 antisense oligonucleotides. 46 Furthermore, MMP-13 antisense oligonucleotide treatments also impair the expression of MMP-9, TGF-b and phosphorylated Smad2 in the TB interface. 46 Increased expression of placental growth factor (PIGF) is observed when MDA-MB-231 cells reach the marrow, and PIGF induces migration of MDA-MB-231 cells via the ERK pathway.…”

“…46 Furthermore, MMP-13 antisense oligonucleotide treatments also impair the expression of MMP-9, TGF-b and phosphorylated Smad2 in the TB interface. 46 Increased expression of placental growth factor (PIGF) is observed when MDA-MB-231 cells reach the marrow, and PIGF induces migration of MDA-MB-231 cells via the ERK pathway. 47 Anti-murine PIGF antibody 5D11D4 treatments prevent metastasis to bone and bone resorption in mice inoculated with either MDA-MB-231 cells or murine melanoma cell line B16/F10 cells.…”