Altered expression of fibronectin and collagens I and IV in multiple myeloma and monoclonal gammopathy of undetermined significance

Abstract

Multiple myeloma (MM) is an incurable B-cell malignancy that arises in the bone marrow (BM). The malignant cells within the BM have extensive interaction with the structural components of their microenvironment. It has been previously shown that the interactions between MM cells and the BM extracellular matrix (ECM) proteins contribute to drug resistance. To understand the underlying causes of adhesion-mediated drug resistance in MM, the components of human BM ECM available for interactions with MM cells must be characterized. We analyzed the expression and localization of fibronectin, laminin, and collagens I and IV in the core biopsies of normal donors and patients with monoclonal gammopathy of undetermined significance (MGUS) or MM. In addition, we compared the patterns of ECM expression in MM patients with low-, mid-, and high-level plasmacytosis of the BM. Although expression of laminin was the same for all groups tested, levels of fibronectin and collagen I were reduced in MM patients with high-level plasmacytosis. Expression of collagen IV in the BM of MGUS and MM patients was higher than in the BM from normal donors. Compared with the plasma cells isolated from the patients with low- and mid-level plasmacytosis, sorted CD138(+) plasma cells from MM patients with high-level plasmacytosis overexpressed collagen IV. Our findings show that, compared with normal controls, the ECM composition of the bone, endosteum, and BM is aberrant in patients with MM, further establishing ECM as a key player in the MM disease process.

Figure 1

Expression of extracellular matrix (ECM) proteins in the human bone. IHC analysis of the core biopsy sections from normal donors (n=5) and patients with monoclonal gammopathy of undetermined significance (MGUS; n=6) and multiple myeloma (MM; n=5 for each of the low/mid/high plasmacytosis groups), showing the staining (brown) of bone marrow (BM), bone, and endosteum for (A) fibronectin, (B) laminin, (C) collagen I, and (D) collagen IV. The entire length of the core biopsy was examined, and images are shown from the representative field of view. (E) High-magnification staining of BM core biopsy serial sections. Bars: A–D = 200 μm; E = 10 μm.

Figure 1

Expression of extracellular matrix (ECM) proteins in the human bone. IHC analysis of the core biopsy sections from normal donors (n=5) and patients with monoclonal gammopathy of undetermined significance (MGUS; n=6) and multiple myeloma (MM; n=5 for each of the low/mid/high plasmacytosis groups), showing the staining (brown) of bone marrow (BM), bone, and endosteum for (A) fibronectin, (B) laminin, (C) collagen I, and (D) collagen IV. The entire length of the core biopsy was examined, and images are shown from the representative field of view. (E) High-magnification staining of BM core biopsy serial sections. Bars: A–D = 200 μm; E = 10 μm.

Figure 1

Expression of extracellular matrix (ECM) proteins in the human bone. IHC analysis of the core biopsy sections from normal donors (n=5) and patients with monoclonal gammopathy of undetermined significance (MGUS; n=6) and multiple myeloma (MM; n=5 for each of the low/mid/high plasmacytosis groups), showing the staining (brown) of bone marrow (BM), bone, and endosteum for (A) fibronectin, (B) laminin, (C) collagen I, and (D) collagen IV. The entire length of the core biopsy was examined, and images are shown from the representative field of view. (E) High-magnification staining of BM core biopsy serial sections. Bars: A–D = 200 μm; E = 10 μm.

Figure 1

Expression of extracellular matrix (ECM) proteins in the human bone. IHC analysis of the core biopsy sections from normal donors (n=5) and patients with monoclonal gammopathy of undetermined significance (MGUS; n=6) and multiple myeloma (MM; n=5 for each of the low/mid/high plasmacytosis groups), showing the staining (brown) of bone marrow (BM), bone, and endosteum for (A) fibronectin, (B) laminin, (C) collagen I, and (D) collagen IV. The entire length of the core biopsy was examined, and images are shown from the representative field of view. (E) High-magnification staining of BM core biopsy serial sections. Bars: A–D = 200 μm; E = 10 μm.

Figure 1

Expression of extracellular matrix (ECM) proteins in the human bone. IHC analysis of the core biopsy sections from normal donors (n=5) and patients with monoclonal gammopathy of undetermined significance (MGUS; n=6) and multiple myeloma (MM; n=5 for each of the low/mid/high plasmacytosis groups), showing the staining (brown) of bone marrow (BM), bone, and endosteum for (A) fibronectin, (B) laminin, (C) collagen I, and (D) collagen IV. The entire length of the core biopsy was examined, and images are shown from the representative field of view. (E) High-magnification staining of BM core biopsy serial sections. Bars: A–D = 200 μm; E = 10 μm.

Figure 2

Contribution of CD138⁺ cells to the expression of fibronectin and collagens I and IV in patients with MM. (A,B) Mononuclear cells from BM needle aspirates from patients with low- (n=6), mid- (n=5), and high- (n=3) grade plasmacytosis were sorted into CD138⁺ and CD138⁻ lymphocyte populations and subjected to real-time quantitative RT-PCR analysis for (A) fibronectin (p>0.05) and (B) collagen IV (p<0.001 for mid/high grade MM compared with low grade). Results presented as percent of GAPDH mRNA expression. (C) Genomic collagen I was amplified from the mononuclear cells from BM needle aspirates (n=3, only Patients 1 and 2 are shown).