Osteopontin is expressed diffusely in tissue sections of hepatic metastases from uveal melanoma, and increased serum osteopontin levels correlate with melanoma metastasis to the liver with high specificity and sensitivity.

Given that expression of many genes changes when cells become malignant or are placed in different microenvironments, we asked whether these changes were accompanied by global reorganization of chromatin. We reasoned that sequestration or exposure of chromatin-sensitive sites to restriction enzymes could be used to detect this reorganization. We found that AluI-sensitive sites of nonmalignant cells were relatively more exposed compared to their malignant counterparts in cultured cells and human tumor samples. Changes in exposure and sequestration of AluI-sensitive sites in normal fibroblasts versus fibrosarcoma or those transfected with oncogenes, nonmalignant breast cells versus carcinomas and poorly metastatic versus highly invasive melanoma were shown to be independent of the cell cycle and may be influenced by proteins rich in disulfide bonds. Remarkably, regardless of degree of malignancy, AluI-sensitive sites became profoundly sequestered when cells were incubated with laminin, Matrigel, or a circular RGD peptide (RGD-C), but became exposed when cells were placed on collagen I or in serum-containing medium. Disruption of the actin cytoskeleton led to exposure, whereas disruption of microtubules or intermediate filaments exerted a sequestering effect. Thus, AluI-sensitive sites are more sequestered with increasing malignant behavior, but the sequestration and exposure of these sites is exquisitely sensitive to information conferred to the cell by molecules and biomechanical forces that regulate cellular and tissue architecture.

Routine histology, the current gold standard, involves staining for specific biomolecules. However, untapped biochemical information in tissue can be gathered using biochemical imaging. Infrared spectroscopy is an emerging modality that allows label-free chemical imaging to derive biochemical information (such as protein, lipids, DNA, collagen) from tissues. Here we employed this technology in order to better predict the development of diabetic nephropathy. Using human primary kidney biopsies or nephrectomies, we obtained tissue from four histologically normal kidneys, four histologically normal kidneys from diabetic subjects and five kidneys with evidence of diabetic nephropathy. A biochemical signature of diabetic nephropathy was derived that enabled prediction of nephropathy based on the ratio of only two spectral frequencies. Nonetheless, using the entire spectrum of biochemical information, we were able to detect renal disease with near perfect accuracy. Additionally, study of sequential protocol biopsies from three transplanted kidneys showed biochemical changes even prior to clinical manifestation of diabetic nephropathy. Thus, infrared imaging can identify critical biochemical alterations that precede morphological changes, potentially allowing for earlier intervention.

The expression of mRNA and distribution of α1(IV), α3(IV) chains of type IV collagen, matrix metalloproteinase 2 (MMP-2), and tissue inhibitor of metallo-proteinase 1 (TIMP-1) were examined in kidneys from streptozotocin-diabetic rats, 2.5 months after administration of the drug, an early time point when specific diabetic glomerular changes were still minimal. Ten age-matched Sprague-Dawley rats were assigned to control and diabetic groups. Compared to the controls, the diabetic rats had a significantly lower body weight, higher kidney weight and serum glucose levels, but no significant changes of glomerular surface area and urine albumin were observed. Northern blot analysis, using whole kidney mRNA, revealed that diabetic rat kidneys expressed 113.5% more α1(IV), 46.5% more α3(IV), 54.8% less MMP-2 and 246% more TIMP-1 (in all instances: p < 0.05). These results were corroborated by in situ hybridization for RNA expression. A quantitative analysis of the data indicated the following changes in glomeruli: (1) 74.6% more α1(IV), (2) 103.8% more α3(IV), (3) 40.7% less MMP-2 and (4) 80.9% more TIMP-1. Similar changes were observed in tubular (proximal and distal) cells. We conclude that an increased synthesis and decreased degradation of renal extracellular matrix components occur early after induction of experimental diabetes, before the onset of typical structural changes in the kidneys, and represent changes of specific gene expression at the transcriptional level. All the cell types in the glomerulus as well as the proximal and distal tubules appear to be involved in this alteration of expression, and this is a novel finding.

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The histological detection of laminin-rich vasculogenic mimicry patterns in human primary uveal melanomas is associated with death from metastases. We therefore hypothesized that highly invasive uveal melanoma cells forming vasculogenic mimicry patterns after exposure to a laminin-rich three-dimensional microenvironment would differentially express genes associated with invasive and metastatic behavior. However, we discovered that genes associated with differentiation (GDF15 and ATF3) and suppression of proliferation (CDKNa1/p21) were up-regulated in highly invasive uveal melanoma cells forming vasculogenic mimicry patterns, and genes associated with promotion of invasive and metastatic behavior such as CD44, CCNE2 (cyclin E2), THBS1 (thrombospondin 1), and CSPG2 (chondroitin sulfate proteoglycan; versican) were down-regulated. After forming vasculogenic mimicry patterns, uveal melanoma cells invaded only short distances, failed to replicate, and changed morphologically from the invasive epithelioid to the indolent spindle A phenotype. In human tissue samples, uveal melanoma cells within vasculogenic mimicry patterns assumed the spindle A morphology, and the expression of Ki67 was significantly reduced in adjacent melanoma cells. Thus, the generation of vasculogenic mimicry patterns is accompanied by dampening of the invasive and metastatic uveal melanoma genotype and phenotype and underscores the plasticity of these cells in response to cues from the microenvironment. The term vasculogenic mimicry describes the formation of perfusion pathways in tumors by highly invasive, genetically deregulated tumor cells 1,2 : vasculogenic because, although these pathways do not form from preexisting vessels, they distribute plasma and may contain red blood cells and mimicry because the pathways are not blood vessels and merely mimic vascular function. In vasculogenic mimicry of the patterned matrix type, 3 highly invasive tumor cells form looping patterns rich in extracellular matrix (ECM) in three-dimensional (3D) culture conditions. 1 Highly invasive tumor cells do not generate these patterns when grown under monolayer conditions or on thin matrix, and poorly invasive tumor cells do not generate these patterns under any culture condition. 1,4 These looping patterns, termed the "fluid-conducting meshwork," 5 connect to endothelial cell-lined blood vessels 4,6 and conduct fluid in vitro 1,4 and in animal models of melanoma. 5,7,8 Vasculogenic mimicry patterns are composed of laminin, 5,9,10 collagen types IV 11 and VI, 12 fibronectin, 13 Pathology, Vol. 169, No. 4, October 2006 Copyright © American Society for Investigative Pathology DOI: 10.2353/ajpath.2006 1376 focally and weakly for collagen I and are structurally different from stromal host-derived fibrovascular septa. There is a strong association between the histological detection of vasculogenic mimicry patterns in primary uveal [15][16][17][18][19][20][21] and cutaneous 22,23 melanomas and subsequent death from metastasis, consistent with the in vitro observatio...

The Map kinase Activating Death Domain containing protein (MADD) isoform of the IG20 gene is over-expressed in different types of cancer tissues and cell lines and it functions as a negative regulator of apoptosis. Therefore, we speculated that MADD might be over-expressed in human breast cancer tissues and that MADD knock-down might synergize with chemotherapeutic or TRAIL-induced apoptosis of breast cancer cells. Analyses of breast tissue microarrays revealed over-expression of MADD in ductal and invasive carcinomas relative to benign tissues. MADD knockdown resulted in enhanced spontaneous apoptosis in human breast cancer cell lines. Moreover, MADD knockdown followed by treatment with TRAIL or doxorubicin resulted in increased cell death compared to either treatment alone. Enhanced cell death was found to be secondary to increased caspase-8 activation. These data indicate that strategies to decrease MADD expression or function in breast cancer may be utilized to increase tumor cell sensitivity to TRAIL and doxorubicin induced apoptosis.