Aberrant type I and type III collagen gene expression in human breast cancer in vivo

MT1-MMP protects breast carcinoma cells against type I collagen-induced apoptosis

As invading breast carcinoma cells breach their underlying basement membrane, they become confronted with a dense three-dimensional reactive stroma dominated by type I collagen. To develop metastatic capabilities, invading tumor cells must acquire the capacity to negotiate this novel microenvironment. Collagen influences the fate of epithelial cells by inducing apoptosis. However, the mechanisms used by invading tumor cells to evade collagen-induced apoptosis remain to be defined. We demonstrate that membrane type-1 matrix metalloproteinase (MT1-MMP/MMP-14) confers breast cancer cells with the ability to escape apoptosis when embedded in a collagen gel and after orthotopic implantation in vivo. In the absence of MMP-14-dependent proteolysis, type I collagen triggers apoptosis by inducing the expression of the pro-apoptotic Bcl-2-interacting killer in luminal-like breast cancer cells. These findings reveal a new mechanism whereby MMP-14 activity promotes tumor progression by circumventing apoptosis.

Determination of paraneoplastic autoimmune responses by tumor cell biology and intratumoral IFN-alpha/IL-12 in breast cancer patients

A wide variety of cancer types has been associated with paraneoplastic autoimmune disorders and with the induction of autoimmunity against several autoantigens, among them self-antigens that are also expressed by tumor cells. This raises the question of autoimmune disorders as a result of immune reactions to the tumor. To date, however, requirements for the generation of autoimmune reactions in cancer patients remain largely unclear. In this study, we characterized conditions in altogether 131 patients, which determine autoimmune responses in primary breast cancer patients. We used ex vivo IFN-γ EliSpot assays against autologous tumor or skin lysates to evaluate tumor- and auto-reactive T-cells (TCs) in the bone marrow (BM) as well as ELISA, ECLIA, and turbidimetric immunoassays for the detection of auto-reactive antibodies in the peripheral blood and compared results to intratumoral cytokine concentrations and pathobiological features of the primary tumor tissue. We here demonstrate a significant correlation between anti-tumor BMTC responses and cellular autoimmune reactivity in primary breast cancer patients (P = 0.002). Humoral autoimmune reactions, however, were negatively correlated with anti-tumor TC immunity (P = 0.039). We observed auto-reactive BMTCs especially in patients with well-differentiated, hormone receptor-positive carcinomas (P = 0.009). Furthermore, elevated concentrations of intratumoral IFN-α significantly correlated with the induction of cellular autoimmune reactivity (P = 0.0002), while humoral autoimmune reactions correlated with increased levels of intratumoral IL-12 (P = 0.04). Altogether, these data indicate a significant role of the tumor microenvironment and particularly that of IFN-α and IL-12 in the induction of systemic autoimmune responses and imply that the primary tumor tissue represents an integral site of autoimmune regulation in cancer patients.

Hypoxic tumor microenvironments reduce collagen I fiber density

Although the mechanisms through which hypoxia influences several phenotypic characteristics such as angiogenesis, selection for resistance to apoptosis, resistance to radiation and chemotherapy, and increased invasion and metastasis are well characterized, the relationship between tumor hypoxia and components of the extracellular matrix (ECM) is relatively unexplored. The collagen I (Col1) fiber matrix of solid tumors is the major structural part of the ECM. Col1 fiber density can increase tumor initiation, progression, and metastasis, with cancer cell invasion occurring along radially aligned Col1 fibers. Here we have investigated the influence of hypoxia on Col1 fiber density in solid breast and prostate tumor models. Second harmonic generation (SHG) microscopy was used to detect differences in Col1 fiber density and volume between hypoxic and normoxic tumor regions. Hypoxic regions were detected by fluorescence microscopy, using tumors derived from human breast and prostate cancer cell lines stably expressing enhanced green fluorescent protein (EGFP) under transcriptional control of the hypoxia response element. In-house fiber analysis software was used to quantitatively analyze Col1 fiber density and volume from the SHG microscopy images. Normoxic tumor regions exhibited a dense mesh of Col1 fibers. In contrast, fewer and structurally altered Col1 fibers were detected in hypoxic EGFP-expressing tumor regions. Microarray gene expression analyses identified increased expression of lysyl oxidase and reduced expression of some matrix metalloproteases in hypoxic compared with normoxic cancer cells. These results suggest that hypoxia mediates Col1 fiber restructuring in tumors, which may impact delivery of macromolecular agents as well as dissemination of cells.

Dynamic interplay between the collagen scaffold and tumor evolution

The extracellular matrix (ECM) is a key regulator of cell and tissue function. Traditionally, the ECM has been thought of primarily as a physical scaffold that binds cells and tissues together. However, the ECM also elicits biochemical and biophysical signaling. Controlled proteolysis and remodeling of the ECM network regulate tissue tension, generate pathways for migration, and release ECM protein fragments to direct normal developmental processes such as branching morphogenesis. Collagens are major components of the ECM of which basement membrane type IV and interstitial matrix type I are the most prevalent. Here we discuss how abnormal expression, proteolysis and structure of these collagens influence cellular functions to elicit multiple effects on tumors, including proliferation, initiation, invasion, metastasis, and therapy response.

Nonlinear optical microscopy and computational analysis of intrinsic signatures in breast cancer

Recently, new non-invasive imaging methods have been developed and applied to cellular and animal mammary models that have enabled breast cancer researchers to track key players and events in mammary metastasis. Noninvasive nonlinear optical methods such as multiphoton laser scanning microscopy (MPLSM), Fluorescence Lifetime Microscopy (FLIM) and second harmonic generation (SHG) imaging provide an unrivaled ability for obtaining high-resolution images from deep within tissue that can be exploited in the quest to understand breast cancer progression. These optical methods can add greatly to our knowledge of cancer progression by allowing key processes to be non-invasively imaged such as metabolism (on the basis of free and bound NADH detection via FLIM) and interactions with the extracellular matrix (SHG imaging of collagen). In this short application note we present a survey of our latest optical and computational efforts to study intrinsic fluorescence in breast cancer models. In particular we present the latest development in our SLIM Plotter application, an open source visualization program for interactive visualization and inspection of combined spectral lifetime (SLIM) data.

Procollagen Alpha 1 Type I: A Potential Aide in Histopathological Grading of Glioma

Collagen type I production has been shown to play a role in malignant transformation. We examined procollagen type I expression in brain tumors and with histopathological grading. Expression levels of procollagen alpha 1 type 1 were determined in 5 glioma cell lines by RT-PCR, Northern, and Western blot analysis. In addition, 41 primary brain tumors and 2 metastatic lung cancers to the brain were examined by PCR. Of the 5 glioma cell line analyzed, 3 (glioma 1, SW-1783 and U-118) expressed procollagen alpha 1 type I and were sensitive to vitamin D3 (VD3). In contrast, 2 of the cell lines (U-373 and T-98G) lacked procollagen alpha 1 type 1 expression. In patients' samples, 14 of 15 anaplastic and low grade gliomas expressed procollagen alpha 1 type I, and 12 of the 14 expressed high levels. In contrast, only 12 of 21 high grade gliomas from patients expressed procollagen alpha 1 type1 and among these, only 4 of the 12 expressed high levels. Thus, there is an inversed correlation between procollagen alpha 1 type 1 expression and histopathological grading (R2=- 0.56, p=0.0005). Our data suggest that procollagen alpha 1 type I expression occurs more commonly in intermediate and low grade gliomas and may assist in histopathological grading.

Analysis of breast cancer by small angle X-ray scattering (SAXS)

Small angle X-ray scattering (SAXS) images of normal breast tissue and benign and malignant breast tumour tissues, fixed in formalin, were measured at the momentum transfer range of 0.063 nm(-1) < or = q (= 4pisin(theta/2)/lambda) < or = 2.720 nm(-1). Four intrinsic parameters were extracted from the scattering profiles (1D SAXS image reduced) and, from the combination of these parameters, another three parameters were also created. All parameters, intrinsic and derived, were subject to discriminant analysis, and it was verified that parameters such as the area of diffuse scatter at the momentum transfer range 0.50 < or = q < or = 0.56 nm(-1), the ratio between areas of fifth-order axial and third-order lateral peaks and third-order axial spacing provide the most significant information for diagnosis (p < 0.001). Thus, in this work it was verified that by combining these three parameters it was possible to classify human breast tissues as normal, benign lesion or malignant lesion with a sensitivity of 83% and a specificity of 100%.

Protease-dependent versus -independent cancer cell invasion programs: three-dimensional amoeboid movement revisited

Tissue invasion during metastasis requires cancer cells to negotiate a stromal environment dominated by cross-linked networks of type I collagen. Although cancer cells are known to use proteinases to sever collagen networks and thus ease their passage through these barriers, migration across extracellular matrices has also been reported to occur by protease-independent mechanisms, whereby cells squeeze through collagen-lined pores by adopting an ameboid phenotype. We investigate these alternate models of motility here and demonstrate that cancer cells have an absolute requirement for the membrane-anchored metalloproteinase MT1-MMP for invasion, and that protease-independent mechanisms of cell migration are only plausible when the collagen network is devoid of the covalent cross-links that characterize normal tissues.

The carboxyl terminal trimer of procollagen I induces pro-metastatic changes and vascularization in breast cancer cells xenografts

BACKGROUND

The COOH terminal peptide of Pro-collagen type I (PICP, also called C3) is chemotactic for endothelial melanoma and breast cancer cells. PICP induces the expression of Metalloproteinases-2 and -9, of Vascular endothelial growth factor and of the chemokine CXCL-12 receptor CXCR4 in MDA MB231 breast carcinoma cells in vitro.

METHODS

We used a model of xenografts in BalbC/nude mice obtaining tumors by implanting in contro-lateral subcutaneous positions MDA MB231 cells added or not with purified PICP and studied the earlier phases of tumor development, up to 48 days from implant, by histology, immunostain and in situ hybridization.

RESULTS

Addition of PICP promotes rapid vascularization of the tumors while does not affect mitotic and apoptotic indexes and overall tumor growth. PICP-treated, relative to control tumors, show up-modulation of Vascular endothelial factor, Metalloproteinase-9 and CXCR4, all tumor prognostic genes; they also show down-modulation of the endogenous Metalloproteinase inhibitor, reversion-inducing-cysteine-rich protein with kazal motifs, and a different pattern of modulation of Tissue Inhibitor of Metalloproteinase-2. These changes occur in absence of detectable expression of CXCL-12, up to 38 days, in control and treated tumors.

CONCLUSION

PICP has an early promoting effect in the acquisition by the tumors of prometastatic phenotype. PICP may be play a relevant role in the productive interactions between stroma and tumor cells by predisposing the tumor cells to respond to the proliferation stimuli ensuing the activation of signaling by engagement of CXCR4 by cytokines and by fostering their extravasion, due to the induction of increased vascular development.

X-ray scattering for classifying tissue types associated with breast disease

Collagen types I and III can be characterized at the molecular level (at the tens to hundreds of nanometers scale) using small angle x-ray scattering (SAXS). Although collagen fibril structural parameters at this length scale have shown differences between diseased and nondiseased breast tissues, a comprehensive analysis involving a multitude of features with a large (>50) patient cohort has not previously been investigated. Breast tissue samples were excised from 80 patients presenting with either a breast lump or reduction mammoplasty. From these, invasive carcinoma, benign tissue, and normal parenchyma were analyzed. Parameters related to collagen structure, including longitudinal (axial) and lateral (equatorial) features, polar angle features, total scattering intensity, and tissue heterogeneity effects, were extracted from the SAXS patterns and examined. The amplitude of the third-order axial peak and the total scattering intensity (amorphous scatter) showed the most separation between tissue groups and a classification model using these two parameters demonstrated an accuracy of over 95% between invasive carcinoma and mammoplasty patients. Normal tissue taken from disease-free patients (mammoplasty) and normal tissue taken from patients with presence of disease showed significant differences, suggesting that SAXS may provide different diagnostic information from that of conventional histopathology.

Genetic association between functional haplotype of collagen type III alpha 1 and chronic hepatitis B and cirrhosis in Koreans

Collagen type III alpha 1 (COL3A1) is one of the extracelluar matrix (ECM) proteins. The expression of COL3A1 is closely related to chronic liver diseases. In this study, we investigated whether single nucleotide polymorphisms (SNPs) of COL3A1 confer genetic susceptibility to patients with hepatitis B virus-infected liver diseases including chronic hepatitis B (CH), liver cirrhosis (CIR), and hepatocellular carcinoma (HCC). A total of 399 Korean (KOR) people, 111 patients with CH, 95 patients with CIR, 86 patients with HCC, and 107 spontaneously recovery, were genotyped for 16 SNPs of the COL3A1 gene. The 'A' allele of rs3106796 was highly associated with the CH [odds ratio (OR) = 1.62, P = 0.01], CIR (OR = 1.67, P = 0.01), and HCC (OR = 1.59, P = 0.03). There were six polymorphic SNPs that could be divided into two linkage disequilibrium (LD) blocks. The haplotype pattern of the KOR control seems to be similar to the patterns displayed in the Japanese, Chinese, and Caucasian populations sampled in the International HapMap project. Haplotype 3 (A-G-A) of the LD block 2 was significantly associated with CH (OR = 2.23, P = 0.02), CIR (OR = 2.24, P = 0.03), and HCC (OR = 2.27, P = 0.03). Moreover, diplotype analysis showed that they had increased relative risk for CH and CIR in the two diplotypes, dt3 (A-G-A/G-G-A; OR = 4.05, P = 0.01) and dt6 (A-A-A/A-G-A; OR = 7.42, P = 0.01 and OR = 5.84, P = 0.05) against dt1 (G-G-A/G-G-A), the most common diplotype in both KOR groups. In vitro reporter gene assays showed that the constructs containing the 'G' allele of rs3106796 appear to exert lower transcriptional activity of COL3A1 than the 'A' allele, depending on the promoter types.

Three-dimensional context regulation of metastasis

Tumor progression ensues within a three-dimensional microenvironment that consists of cellular and non-cellular components. The extracellular matrix (ECM) and hypoxia are two non-cellular components that potently influence metastasis. ECM remodeling and collagen cross-linking stiffen the tissue stroma to promote transformation, tumor growth, motility and invasion, enhance cancer cell survival, enable metastatic dissemination, and facilitate the establishment of tumor cells at distant sites. Matrix degradation can additionally promote malignant progression and metastasis. Tumor hypoxia is functionally linked to altered stromal-epithelial interactions. Hypoxia additionally induces the expression of pro-migratory, survival and invasion genes, and up-regulates expression of ECM components and modifying enzymes, to enhance tumor progression and metastasis. Synergistic interactions between matrix remodeling and tumor hypoxia influence common mechanisms that maximize tumor progression and cooperate to drive metastasis. Thus, clarifying the molecular pathways by which ECM remodeling and tumor hypoxia intersect to promote tumor progression should identify novel therapeutic targets.

Imatinib mesylate inhibits proliferation and exerts an antifibrotic effect in human breast stroma fibroblasts

Tumor stroma plays an important role in cancer development. In a variety of tumors, such as breast carcinomas, a desmoplastic response, characterized by stromal fibroblast and collagen accumulation, is observed having synergistic effects on tumor progression. However, the effect of known anticancer drugs on stromal cells has not been thoroughly investigated. Imatinib mesylate is a selective inhibitor of several protein tyrosine kinases, including the receptor of platelet-derived growth factor, an important mediator of desmoplasia. Recently, we have shown that imatinib inhibits the growth and invasiveness of human epithelial breast cancer cells. Here, we studied the effect of imatinib on the proliferation and collagen accumulation in breast stromal fibroblasts. We have shown that it blocks the activation of the extracellular signal-regulated kinase and Akt signaling pathways and up-regulates cyclin-dependent kinase inhibitor p21(WAF1), leading to the inhibition of fibroblast proliferation, by arresting them at the G(0)/G(1) phase of the cell cycle. Imatinib inhibits more potently the platelet-derived growth factor-mediated stimulation of breast fibroblast proliferation. By using specific inhibitors, we have found that this is due to the inhibition of the Akt pathway. In addition, imatinib inhibits fibroblast-mediated collagen accumulation. Conventional and quantitative PCR analysis, as well as gelatin zymography, indicates that this is due to the down-regulation of mRNA synthesis of collagen I and collagen III-the main collagen types in breast stroma-and not to the up-regulation or activation of collagenases matrix metalloproteinase 2 and matrix metalloproteinase 9. These data indicate that imatinib has an antifibrotic effect on human breast stromal fibroblasts that may inhibit desmoplastic reaction and thus tumor progression.

Procollagen I COOH-terminal fragment induces VEGF-A and CXCR4 expression in breast carcinoma cells

The COOH-terminal fragment of procollagen type I (C3) is produced in tissues with high synthesis of collagen I, such as in breast cancer stroma and in bone. We previously demonstrated that C3 is chemoattractant for breast carcinoma and endothelial cells, and that in tumor cells it induces expression and activation of metalloproteinases (MMP) -2 and -9. Here we demonstrate that C3 induces expression of vascular-endothelial growth factor (VEGF) and of CXCR4, the receptor of the CXCL12/SDF-1 chemokine, in MDA MB 231 breast cancer cells. We show that the changes in gene expression and motility induced by C3 occur in a timely succession and are mediated by multiple and different signaling pathways. C3 induces early phosphorylation of p38/MAPK. Induction of VEGF expression requires continual activity of p38/MAPK and of Protein Kinase C (PKC). Pro-MMP-2 and -9 are induced through a signaling pathway involving G0alpha.i protein, and cell migration requires the activity of a combination of these signaling pathways. Our results suggest that C3 acts as a stromal-derived, cancer-promoting agent active in inducing the migratory phenotype and the survival of cancer cells and determining timely changes in their gene expression that establish conditions promoting tumor angiogenesis and invasion.

Diagnosing breast cancer using diffuse reflectance spectroscopy and intrinsic fluorescence spectroscopy

Using diffuse reflectance spectroscopy and intrinsic fluorescence spectroscopy, we have developed an algorithm that successfully classifies normal breast tissue, fibrocystic change, fibroadenoma, and infiltrating ductal carcinoma in terms of physically meaningful parameters. We acquire 202 spectra from 104 sites in freshly excised breast biopsies from 17 patients within 30 min of surgical excision. The broadband diffuse reflectance and fluorescence spectra are collected via a portable clinical spectrometer and specially designed optical fiber probe. The diffuse reflectance spectra are fit using modified diffusion theory to extract absorption and scattering tissue parameters. Intrinsic fluorescence spectra are extracted from the combined fluorescence and diffuse reflectance spectra and analyzed using multivariate curve resolution. Spectroscopy results are compared to pathology diagnoses, and diagnostic algorithms are developed based on parameters obtained via logistic regression with cross-validation. The sensitivity, specificity, positive predictive value, negative predictive value, and overall diagnostic accuracy (total efficiency) of the algorithm are 100, 96, 69, 100, and 91%, respectively. All invasive breast cancer specimens are correctly diagnosed. The combination of diffuse reflectance spectroscopy and intrinsic fluorescence spectroscopy yields promising results for discrimination of breast cancer from benign breast lesions and warrants a prospective clinical study.

Impact of the non-cellular tumor microenvironment on metastasis: potential therapeutic and imaging opportunities

Evidence is accumulating that the malignant phenotype of a given tumor is dependent not only on the intrinsic characteristics of tumor cells, but also on the cooperative interactions of non-neoplastic cells, soluble secreted factors and the non-cellular solid-state ECM network that comprise the tumor microenvironment. Given the ability of the tumor microenvironment to regulate the cellular phenotype, recent efforts have focused on understanding the molecular mechanisms by which cells sense, assimilate, interpret, and ultimately respond to their immediate surroundings. Exciting new studies are beginning to unravel the complex interactions between the numerous cell types and regulatory factors within the tumor microenvironment that function cooperatively to control tumor cell invasion and metastasis. Here, we will focus on studies concerning a common theme, which is the central importance of the non-cellular solid-state compartment as a master regulator of the malignant phenotype. We will highlight the non-cellular solid-state compartment as a relatively untapped source of therapeutic and imaging targets and how cellular interactions with these targets may regulate tumor metastasis.

Comparative proteome analysis of human epithelial ovarian cancer

Background

Epithelial ovarian cancer is a devastating disease associated with low survival prognosis mainly because of the lack of early detection markers and the asymptomatic nature of the cancer until late stage. Using two complementary proteomics approaches, a differential protein expression profile was carried out between low and highly transformed epithelial ovarian cancer cell lines which realistically mimic the phenotypic changes observed during evolution of a tumour metastasis. This investigation was aimed at a better understanding of the molecular mechanisms underlying differentiation, proliferation and neoplastic progression of ovarian cancer.

Results

The quantitative profiling of epithelial ovarian cancer model cell lines TOV-81D and TOV-112D generated using iTRAQ analysis and two-dimensional electrophoresis coupled to liquid chromatography tandem mass spectrometry revealed some proteins with altered expression levels. Several of these proteins have been the object of interest in cancer research but others were unrecognized as differentially expressed in a context of ovarian cancer. Among these, series of proteins involved in transcriptional activity, cellular metabolism, cell adhesion or motility and cytoskeleton organization were identified, suggesting their possible role in the emergence of oncogenic pathways leading to aggressive cellular behavior.

Conclusion

The differential protein expression profile generated by the two proteomics approaches combined to complementary characterizations studies will open the way to more exhaustive and systematic representation of the disease and will provide valuable information that may be helpful to uncover the molecular mechanisms related to epithelial ovarian cancer.

The evolution of collagen expression in sarcomatoid renal cell carcinoma

The development of a sarcomatoid morphotype is recognized as an extreme form of dedifferentiation in renal cell carcinoma and is associated with a poor prognosis. Although sarcomatoid renal cell carcinoma shows pronounced spindle cell morphology, clear cell renal cell carcinoma may show early spindle cell change with cellular elongation, and the prognostic significance of this is debated. To determine the relationship between sarcomatoid renal cell carcinoma and clear cell renal cell carcinoma showing early spindle cell change, we have investigated collagen expression using immunohistochemistry in these 2 tumor types. Both sarcomatoid renal cell carcinoma and early spindle cell change tumors showed pericellular interstitial expression of collagen types I and III, whereas sarcomatoid renal cell carcinoma also showed cytoplasmic expression of these collagen types. Expression of these collagen types in typical clear cell renal cell carcinoma was, in occasional cases, limited to faint and patchy staining in a pericellular interstitial distribution. Tumor cells did not stain for collagen type IV in sarcomatoid renal cell carcinoma, early spindle cell change, or typical clear cell renal cell carcinoma. In sarcomatoid renal cell carcinoma, there was diffuse pericellular expression of collagen type V and patchy pericellular expression of collagen type VI, whereas early spindle cell change tumors showed patchy pericellular staining with antibodies to collagen type V. Collagen type VI expression in early spindle cell change was largely confined to the vascular adventitia and areas of scarring, although very occasional foci of faint interstitial staining were also seen. In typical clear cell renal cell carcinoma, staining of collagen types V and VI was limited to the vascular adventitia and foci of desmoplasia, whereas no staining of tumor cell cytoplasm were seen. This study has shown that collagen expression of sarcomatoid renal cell carcinoma differs from that of early spindle cell change and provides validating evidence that these 2 morphotypes should not be considered together for classification purposes.

Quantitative analysis of estrogen receptor heterogeneity in breast cancer

Immunohistochemical analyses (IHC) of biomarkers are extensively used for tumor characterization and as prognostic and predictive measures. The current standard of single slide analysis assumes that one 5 microM section is representative of the entire tumor. We used our automated image analysis technology (AQUA) using a modified IHC technique with fluorophores to compare estrogen receptor (ER) expression in multiple blocks/slides from cases of primary breast cancer with the objective of quantifying tumor heterogeneity within sections and between blocks. To normalize our ER scores and allow slide-to-slide comparisons, 0.6 microm histospots of representative breast cancer cases with known ER scores were assembled into a 'gold standard array' (GSA) and placed adjacently to each whole section. Overall, there was excellent correlation between AQUA scores and the pathologist's scores and reproducibility of GSA scores (mean linear regression R value 0.8903). Twenty-nine slides from 11 surgical cases were then analyzed totaling over 2000 AQUA images. Using standard binary assignments of AQUA (>10) and pathologist's (>10%) scores as being positive, there was fair concordancy between AQUA and pathologist scores (73%) and between slides from different blocks from the same cases (75%). However using continuous AQUA scores, agreement between AQUA and pathologist was far lower and between slides from different blocks from the same cases only 19%. Within individual slides there was also significant heterogeneity in a scattered pattern, most notably for slides with the highest AQUA scores. In sum, using a quantitative measure of ER expression, significant block-to-block heterogeneity was found in 81% of cases. These results most likely reflect both laboratory-based variability due to lack of standardization of immunohistochemistry and true biological heterogeneity. It is also likely to be dependent on the biomarker analyzed and suggests further studies should be carried out to determine how these findings may affect clinical decision-making processes.

Wavelet-based feature extraction applied to small-angle x-ray scattering patterns from breast tissue: a tool for differentiating between tissue types

This paper reports on the application of wavelet decomposition to small-angle x-ray scattering (SAXS) patterns from human breast tissue produced by a synchrotron source. The pixel intensities of SAXS patterns of normal, benign and malignant tissue types were transformed into wavelet coefficients. Statistical analysis found significant differences between the wavelet coefficients describing the patterns produced by different tissue types. These differences were then correlated with position in the image and have been linked to the supra-molecular structural changes that occur in breast tissue in the presence of disease. Specifically, results indicate that there are significant differences between healthy and diseased tissues in the wavelet coefficients that describe the peaks produced by the axial d-spacing of collagen. These differences suggest that a useful classification tool could be based upon the spectral information within the axial peaks.

Localization of precursor proteins and mRNA of type I and III collagens in usual interstitial pneumonia and sarcoidosis

The aim of this study was to assess and compare the accumulation and distribution of newly synthesized type I and III collagens in usual interstitial pneumonia (UIP) and pulmonary sarcoidosis. Lung biopsies from 10 patients with UIP and 13 patients with sarcoidosis were investigated by immunohistochemical technique and mRNA in situ hybridization. The antibodies for the aminoterminal propeptide of type I procollagen and the aminoterminal propeptide of type III procollagen (PINP and PIIINP, respectively) were used. When compared to healthy lung, levels of type I pN- and type III pN-collagens were increased in both of these disorders. Type I procollagen was mostly present as intracellular spots in newly formed fibrosis in UIP while type III pN-collagen was expressed extracellularly underneath metaplastic alveolar epithelium. Type I procollagen was present intracellularly within and around the granulomas of sarcoidosis, whereas type III pN-collagen was expressed extracellularly, mainly around the granulomas. mRNAs of both collagens colocalized with the precursor proteins. We conclude that the expression of precursor proteins and mRNA of type I and type III collagens is increased in UIP and sarcoidosis, reflecting mainly active synthesis of these collagens in different areas of the lung.

Differential gene expression in a paclitaxel-resistant clone of a head and neck cancer cell line

The anti-neoplastic drug paclitaxel (taxol), which is known to block cells in the G2/M phase of the cell cycle through stabilization of microtubules, is meanwhile commonly used for chemotherapy of advanced head and neck cancer. Chemotherapy is primarily used in order to preserve laryngeal and/or pharyngeal structures. Although paclitaxel generally seems to be a powerful agent, it failed to reach a loco-regional tumor control in a sufficient percentage of patients. In order to investigate molecular resistance mechanisms, we have established a paclitaxel-resistant subline originating from the larynx carcinoma cell line HLaC79, which seemed to be partially dependent on taxol. The original and the descendant cell line were characterized by growth inhibition assays. We used western blotting and the cDNA subtraction (SSH) technique to identify genes differentially expressed in the taxol-resistant cell clone. cDNA subtraction revealed increased expression of six genes, including clathrin heavy chain, alpha3-tubulin, a neuroblastoma-specific Thymosin beta, the ribosomal protein L7a, HLA-B associated transcript 3 and collagen IIIalpha1 in the taxol-resistant cell line. Furthermore, western blots showed an overexpression of MDR-1 in the taxol-resistant clone, while alpha- and beta-tubulins and p48/IRF9 were expressed in equal amounts in both cell lines.

Simulation of small-angle x-ray scattering from collagen fibrils and comparison with experimental patterns

Simulation of small-angle x-ray scattering from collagen in healthy and cancerous breast tissue may reveal detailed information on the structural changes in collagen. Collagen fibril is modelled as a cylinder with axially periodic step-function electron density, and packing is approximated by placing the cylinders in small hexagonal bundles. The intensity from a bundle is calculated by summing analytical scattering amplitudes from the cylinders, and intensities from several bundles with varying lattice constants are averaged. Comparisons with more complex models are made to estimate the robustness of the model. The oscillations in the equatorial direction are not significantly affected by added complexity. The relative intensities of the Bragg peaks in the meridional direction can be tuned by modifying the axial electron density distribution. Tests with different fibril radius distributions show that the average radius can be determined with an accuracy of +/-0.5 nm but that the shape of the radius distribution cannot be accurately determined from the scattering patterns. The effect of multiple scattering and the detector point-spread function (PSF) is considered, and the PSF may make a significant contribution to the final slope of the scattering pattern. Comparisons with observed scattering indicate that the model is basically correct at the supra-molecular level.

Lack of Telopeptides in Fibrillar Collagen I Promotes the Invasion of a Metastatic Breast Tumor Cell Line

Defective fibrillar collagen polymerization in primary tumors has been correlated with increased metastasis. However, it is unclear how collagen organization influences tumor invasion. In this study, we show that collagen I polymerized without telopeptides (the flanking regions of collagen molecules) can differentially affect the three-dimensional migration of mammary carcinoma cells. MDA-MB-231 cells capable of proteolytic degradation and mesenchymal motion, invaded telopeptide-intact and telopeptide-free collagen gels to the same extent. In contrast, MDA-MB-435S cells, with typical features of amoeboid cells (poor collagenolytic activity, rounded cell morphology), were 5-fold more invasive in telopeptide-free than telopeptide-intact collagen. A fraction of the MDA-MB-435S cells that invaded telopeptide-intact or telopeptide-free collagen had a rounded morphology; however, in telopeptide-free collagen, a significant fraction of the cells switched from a rounded to elongated morphology (protrusion formation). The dynamic changes in cellular shape facilitated MDA-MB-435S locomotion through the narrow interfiber gaps, which were smaller than cell diameters. Based on the spherical morphology of MDA-MB-435S cells, we tested if the changes in cell shape and invasion were related to RhoA-ROCK activity; GTP-bound RhoA was measured in pull-down assays. RhoA activity was 1.8-fold higher for MDA-MB-435S cells seeded on telopeptide-free than telopeptide-intact collagen. Y27632 inhibition of ROCK, a Rho effector, significantly reduced the changes in cellular morphodynamics and the invasion of MDA-MB-435S cells but did not alter the invasion of MDA-MB-231 cells. Thus, the higher RhoA activity of MDA-MB-435S cells in telopeptide-free collagen enhances the changes in cellular morphodynamics associated with motility and invasion.

Human breast cancerin vitro: matching histo-pathology with small-angle x-ray scattering and diffraction enhanced x-ray imaging

Twenty-eight human breast tumour specimens were studied with small-angle x-ray scattering (SAXS), and 10 of those were imaged by the diffraction enhanced x-ray imaging (DEI) technique. The sample diameter was 20 mm and the thickness 1 mm. Two examples of ductal carcinoma are illustrated by histology images, DEI, and maps of the collagen d-spacing and scattered intensity in the Porod regime, which characterize the SAXS patterns from collagen-rich regions of the samples. Histo-pathology reveals the cancer-invaded regions, and the maps of the SAXS parameters show that in these regions the scattering signal differs significantly from scattering by the surrounding tissue, indicating a degradation of the collagen structure in the invaded regions. The DEI images show the borders between collagen and adipose tissue and provide a co-ordinate system for tissue mapping by SAXS. In addition, degradation of the collagen structure in an invaded region is revealed by fading contrast of the DEI refraction image. The 28 samples include fresh, defrosted tissue and formalin-fixed tissue. The d-values with their standard deviations are given. In the fresh samples there is a systematic 0.76% increase of the d-value in the invaded regions, averaged over 11 samples. Only intra-sample comparisons are made for the formalin-fixed samples, and with a long fixation time, the difference in the d-value stabilizes at about 0.7%. The correspondence between the DEI images, the SAXS maps and the histo-pathology suggests that definitive information on tumour growth and malignancy is obtained by combining these x-ray methods.

Synthesis and maturation of type I and type III collagens in endometrial adenocarcinoma

OBJECTIVE

The structure and distribution of type I and type III collagens in the extracellular matrix of malignant endometrium was evaluated for their roles in the development and progression of this neoplasm.

STUDY DESIGN

Collagen synthesis and deposition in endometrial adenocarcinomas was determined by immunohistochemical analysis of type I and type III procollagen and verified by computer-assisted morphometry and in situ hybridization.

RESULTS

In the stroma of well-differentiated adenocarcinomas increased intracellular collagen synthesis was observed in fibroblastic cells as well as increased extracellular formation of newly synthesized type I and type III procollagen. Collagen maturation was also rapid. In moderately differentiated tumors, destruction and dissolution occurred around invading islets, concomitantly with decreased deposits of both collagens, despite increases in corresponding mRNAs. In poorly differentiated neoplasms, solid epithelial islets coexisted with sparse and distinctly collagen-positive stroma. Poorly differentiated neoplasms also contained tumor cells exhibiting intracellular collagen staining as well as in situ hybridization signals. In highly malignant papillary adenocarcinomas, the tumor cells induced distinctly increased collagen synthesis and deposition of newly synthesized collagen but not the mature cross-linked protein.

CONCLUSIONS

In malignancy, compression of surrounding stroma and a fibroproliferative response with increased collagen synthesis and deposition may prevent tumor growth. In more advanced lesions, stromal dissolution may permit tumor spread and in highly malignant lesions an abnormal stroma may promote neoplasm progression.

Procollagen 1 expression in atypical fibroxanthoma and other tumors

BACKGROUND

Procollagen (PC) is secreted by fibroblasts into the extracellular matrix, where it is cleaved to form collagen. The rat anti-human PC-1 monoclonal antibody has been reported to react with atypical fibroxanthoma (AFX), a poorly differentiated but usually benign skin lesion common in elderly patients. We have studied PC-1 staining in 50 tumors with AFX histological features (four of which were subsequently reclassified as non-AFX tumors) to confirm this prior observation. In addition, we have investigated PC-1 in other skin tumors, particularly those with spindled cell or sclerosing/desmoplastic morphologies.

METHOD

Archival material was retrieved and sections were prepared and immunostained with PC-1 as well as a panel of antibodies, including S-100 and MNF-116 (cytokeratins 5, 6, 7, 8, 17, and 19).

RESULTS

PC-1 staining was strongly positive in 40 of 46 (87%) AFXs. Three AFXs displayed weak staining with PC-1 even after repeat staining of 10 tumors that were initially weak. Three additional tumors stained with both PC-1 and MNF-116 and were classified as AFX-like squamous cell carcinoma (SCC). One tumor with AFX-like histology was PC-1 negative and S-100 positive and was classified as an AFX-like melanoma. Positive staining in tumor cells was observed in three of nine (33%) desmoplastic malignant melanomas, three of eight (38%) desmoplastic SCCs, zero of 10 (0%) desmoplastic trichoepitheliomas, zero of 10 (0%) morpheic basal cell carcinomas, and zero of 10 (0%) sclerosing sweat duct carcinomas.

CONCLUSION

PC-1 is a useful antibody in a diagnostic immunohistochemical panel when investigating AFX and AFX-like tumors; however, good technical quality and careful interpretation are necessary when using a panel of antibodies, particularly to keratin and S-100 protein, for optimal accuracy.

Integrated transcriptome analysis of the cellular mechanisms associated with Ha-ras-dependent malignant transformation of the human breast epithelial MCF7 cell line

To understand the cellular mechanisms of malignant transformation induced by constitutive activation of the ras oncogene (Ha-ras), we used a subtractive hybridization method (VGID) together with an integrative analytical procedure based upon literature databases in the form of extensive interaction graphs. We found 166 over- and under-expressed genes which, in the human MCF7-ras breast epithelial cell line, are involved in the different aspects of tumoral transformation such as defined signaling pathways, cellular growth, protection against apoptosis, extracellular matrix and cytoskeleton remodeling. Integrative analysis led to the construction of a physiological model defining cross-talk and signaling pathway alterations which explicitly suggested mechanisms directly involved in tumor progression. The model further suggested points and means of intervention which could induce cell death in Ha-ras-transformed cells specifically. These hypotheses were directly tested in vitro and found to be largely correct, hence indicating that these new analytical and technological approaches allow the discovery of pathology-associated cellular mechanisms and physiologically defined targets leading to phenotype-specific pharmacological interventions.

Pro-collagen I COOH-terminal trimer induces directional migration and metalloproteinases in breast cancer cells

Breast and prostatic carcinomas, melanoma, and endothelial cell lines are chemoattracted by medium conditioned by mature osteoblasts. The chemoattractant for endothelial cells was identified with C3, carboxyl-terminal trimer of pro-collagen type I. We report that C3 induces directional migration and proliferation, the expression of tissue inhibitor of metalloproteinases-2, pro-metalloproteinase-2 and -9, and their activation in MDA MB231 cells, without changing the expression of tissue inhibitor of metalloproteinases-1 and of metalloproteinase-14. Antiserum against metalloproteinase-2 or -9 or -14, tissue inhibitor of metalloproteinases-1, or GM6001 inhibits the C3-induced migration. Urokinase and its receptor are detected and unchanged upon exposure to C3. The antibody against urokinase or addition of plasminogen activator inhibitor inhibits migration. Blocking antibodies to integrins alpha(2), alpha(6), beta(1), and beta(3) inhibit chemotaxis and do not change urokinase and urokinase receptor expression. Blockage of alpha(2), beta(1), and beta(3) integrins affect differently the induction by C3 of pro-metalloproteinase-2 and -9 and of tissue inhibitor of metalloproteinases-2. Chemotaxis to C3 is also inhibited by genistein, by pertussis toxin, which also inhibits C3-induced pro-metalloproteinase -2 and -9, but not urokinase expression. Wortmannin partially inhibits C3-induced cell migration. Other, but not all, breast carcinoma lines tested responded to C3 with migration and pro-metalloproteinase-2 induction. Presently C3 is the only agent known to induce migration specifically of both endothelial and breast carcinoma cells. The mitogenic and motogenic role of C3 in vitro might prefigure a role in in vivo carcinogenesis and in the establishment of metastasis.

[Ossification in lung metastases of primary colorectal adenocarcinomas]

Ossification of lung tissue is a rare phenomenon, which can be found in association with carcinoid tumors of the lung or pulmonary blastomas. Very rarely, ossifications are observed in lung metastases of extrathoracal epithelial tumors. In these cases, the most probable primary focus is a colorectal adenocarcinoma. Our question was, whether ossifications in lung metastases are pathognomonic for colorectal adenocarcinomas and how they can be pathogenetically arranged. A total of 15 lung metastases with ossifications from 5 patients suffering from a colorectal adenocarcinoma were examined by means of immunohistochemistry. Thereby, we found an increased expression of bone morphogenetic protein (BMP) 2/4 and osteonectin in tumor cells, as well as an increased stromatogenous expression of collagen type III. We conclude that there is strong evidence of a primary colorectal adenocarcinoma when ossifications in lung metastases are found. In these cases, a common metastatic spread of tumor cells and tumor stroma seems to be probable.

In vivo investigation of progressive alterations in rat mammary gland tumors by near-infrared spectroscopy

We have investigated mammary gland tissues of female rats treated with 7,12-dimethylbenz[a]anthracene in sesame oil by a near infrared (NIR) spectroscopy finding that the DNA and water contents in the cancerous tissues were larger than those in the normal tissues but that the lipid content in the former was less than that in the latter. With protein contents, however, little difference was observed between the two. Thus, we used a lipid band around 1725 nm (the first overtone of n-alkane) and a protein band around 2054 nm (a combination band of amide A and amide II of polypeptides) for a quantitative evaluation of malignant changes in the mammary gland tissues. The lipid/protein band intensity ratios were calculated from the spectra of the mammary glands in the control animals and those of the noncancerous and cancerous sites in the treated animals. The lipid/protein ratios in the control animals, in the noncancerous sites, and in the cancerous sites were 1.452 +/- 0.221 (n = 5), 0.728 +/- 0.069 (n = 5), and 0.362 +/- 0.060 (n = 5), respectively. These values were significantly different from each other (P < 0.001). The lipid changes observed by near-infrared (NIR) spectroscopy were confirmed by the results obtained from chemical methods for the evaluation of lipid levels in the same samples. Thus, our NIR spectroscopic method would be able not only to discriminate between cancerous and normal tissues but also to distinguish animals with cancers from normal animals. In addition, as the cancer grew, the lipid band intensity decreased, this band was shifted to higher wavelengths, and collagen peaks appeared in the tissues. These findings were supported by histological examinations of the cancerous and normal tissues. The present study indicates that NIR spectroscopy has high specificity and sensitivity in discriminating cancerous tissues from normal mammary glands in animals and it may offer potential for noninvasive, in vivo diagnosis of female breast cancer in the near future.

Collagen type I expression in experimental anaplastic thyroid carcinoma: regulation and relevance for tumorigenicity

Fibrosis in solid malignancies plays a significant role in tumor pathophysiology. Potential mechanisms for collagen type I deposition in anaplastic thyroid carcinoma (ATC) were investigated using 6 characterized ATC cell lines. Three of these cell lines, which produced collagen type I, had, as a group, a poor tumorigenicity when inoculated in athymic mice. This group of cells generated tumors in 4 of 24 injected animals (17%). Pro-alpha 1(I) collagen mRNA-expressing carcinoma and stromal cells were interdispersed in the tumors generated by these ATC cells. By contrast, the 3 noncollagen-producing ATC cell lines were all tumorigenic with a tumor take of 60% in the whole group. In the latter tumors, pro-alpha 1(I) collagen mRNA-expressing cells were confined to the stromal compartment, well delineated from carcinoma cell islets. To study the influence of ATC cells on collagen type I synthesis by fibroblasts, we used AG 1518 diploid human fibroblasts cultured on poly-(2-hydroxyethyl methacrylate) (poly[HEMA])-coated plates. This culture condition allows the study of the effect of collagen mRNA translation in the regulation of collagen type I synthesis. Conditioned media from the 6 ATC cell lines did not influence collagen synthesis. The ATC cell line KAT-4 stimulated fibroblast synthesis of collagen type I when the two cell types were cocultured on poly[HEMA]-coated substrates. Specific inhibitors of PDGF and TGF-beta reduced the KAT 4 carcinoma cell-induced stimulation of collagen type I synthesis. Our data suggest that collagen type I production by carcinoma cells correlates negatively with tumorigenicity and that the formation of a well-defined stroma is of importance for tumor growth. Furthermore, our data suggest that tumor cells are able to stimulate collagen mRNA translation in stromal fibroblasts in direct cell-cell contact by, at least in part, transferring PDGF or TGF-beta.

Reactive stroma in prostate cancer progression

PURPOSE

The development of an altered stromal microenvironment in response to carcinoma is a common feature of many tumors. We reviewed the literature describing characteristics of reactive stroma, how reactive stroma affects cancer progression and how carcinoma regulates reactive stroma. Moreover, we present a hypothesis of reactive stroma in prostate cancer and discuss how the biology of reactive stroma may be used in novel diagnostic and therapeutic approaches.

MATERIALS AND METHODS

An extensive literature search was performed to review reports of the general features of wound repair stroma, general stromal responses to carcinoma, and stromal biology of normal and prostate cancer tissues. These studies were analyzed and a reactive stroma hypothesis in prostate cancer was developed.

RESULTS

Modifications to the stroma of breast, colon and prostate tumors parallel the generation of granulation tissue in wound repair. These changes include stromal cell phenotypic switching, extracellular matrix remodeling and angiogenesis induction. Therefore, it is predicted that a modified wound healing response induces the formation of reactive stroma in cancer to create a tumor promoting environment. Based on its role in wound repair and its over expression in prostate cancer, transforming growth factor-beta stands out as a potential regulator of reactive stroma.

CONCLUSIONS

Reactive stroma in prostate cancer and granulation tissue in wound repair show similar biological responses and processes that are predicted to promote cancer progression. Further identification of specific functional and regulatory mechanisms in prostate cancer reactive stroma may aid in the use of reactive stroma for novel diagnostic and therapeutic approaches.

Colorectal cancer metastatic phenotype stimulates production by fibroblasts of N-terminal peptide of type III collagen: clinical implications for prognosis

In this study we assessed whether the serum levels of the N-terminal peptide of type III collagen (PIIIP), an index of type III collagen synthesis, are influenced by colorectal cancer stage, and whether "in vitro" fibroblast growth and PIIIP production could be altered by tumor tissues obtained from metastatic and nonmetastatic colorectal cancer. 208 colorectal cancer patients (115 colon and 93 rectum) were studied; 54 were stage I, 62 stage II, 37 stage III and 55 stage IV. PIIIP serum levels were significantly higher in stage IV as compared to all other patient groups. The 5-year survival of stage I, stage II, stage III and stage IV patients were 87%, 88%, 32% and 20%, respectively. In the subgroup of stage I and stage II patients considered together, PIIIP (> 0.5 U/ml), but not CEA (> 5 microg/l) serum levels, were predictive for survival. Fibroblast growth was significantly inhibited, while PIIIP production was significantly enhanced, when these cells were conditioned with colorectal cancer homogenates obtained from patients with distant metastases, than from those without distant metastases. In conclusion, colorectal tumors, when metastatic, stimulate fibroblasts' PIIIP synthesis and the serum levels of this peptide might predict patients' outcome after radical surgery.

Collagen matrix in development and progression of experimentally induced respiratory neoplasms in the hamster

Intratracheal instillations of 7H-dibenzo(c, g)carbazole (DBC), a tobacco smoke component, into Syrian golden hamsters, resulted in preneoplastic lesions and benign and malignant respiratory neoplasms. Neoplastic progression was associated with specific changes in the extracellular matrix (ECM), dependent on the stage of tumor development. DBC-induced tracheobronchial squamous metaplasia was associated with an increase in collagen type I and type III deposition in the subepithelial ECM, as observed by computer-assisted image analysis of immunohistochemical staining for the aminoterminal propeptides of collagen type I (PINP) and collagen type III (PIIINP). Increased collagen matrix synthesis was detected in dysplasia by in situ hybridization of alpha1(I) mRNA for collagen I and alpha1(III) mRNA for collagen type III after continued exposure to DBC. In well-differentiated squamous cell carcinomas with an expansive growth pattern, collagen deposition increased, as did fiber size. In moderately differentiated neoplasms, basement membrane (BM) destruction and invasion was associated with a destructive growth pattern and decreases in collagen synthesis and the deposition of new collagen. Preserved deposition of mature collagen was detected by staining for the telopeptide of collagen type I propeptide. In less differentiated tumors, ECM development was minimal, with few and small fibers, possibly explaining the rapid development of these neoplasms. Transforming growth factor beta (TGFbeta1) immunoreactivity was increased in hyperplastic epithelium and well differentiated neoplasms and decreased in dysplasia and less differentiated squamous cell carcinomas, while TGFbeta2 and TGFbeta3 expression was also distinct in neoplastic cells. Collagen synthesis and epithelial differentiation were associated with an increased number of myofibroblasts in the ECM and with increased TGFbeta3 immunoreactivity in differentiated cells and in the matrix. The nature of the composition of the ECM was related to neoplastic growth and progression when analyzed by computer-associated image analysis, revealing alterations in collagen structure, size, and shape.

Changes in gene expression during progression of ovarian carcinoma

The molecular events leading to the development and progression of serous ovarian carcinoma are not completely understood. We performed a large scale survey for the identification of differentially expressed genes in serous ovarian carcinoma by using cDNA array analysis. Differences in gene expression between serous adenocarcinoma and benign serous adenoma, and between advanced and/or moderately or poorly differentiated and local, highly differentiated serous adenocarcinoma were assessed. The most striking difference between adenocarcinoma and benign adenoma was upregulation of RHOGDI2 in the carcinomas irrespective of the clinical tumor stage. Other changes in carcinoma were upregulation of MET and Ne-dlg, and downregulation of HGFAC, desmin, and PDGFA. The most prominent differences between advanced and local adenocarcinoma were upregulation of COL3A1, CFGR, and MET in advanced carcinoma, and downregulation of HGFAC, FZD3, and BFL1 in the same tumors. In conclusion, significant differences were found in the gene expression between benign and malignant serous ovarian tumors, and between local, highly differentiated and advanced and/or moderately or poorly differentiated serous adenocarcinomas. The differentially expressed genes may be related to the carcinogenesis and progression of the malignant growth.

Ets factors and regulation of the extracellular matrix

Ets factors are critical mediators of extracellular matrix (ECM) remodelling. As the spectrum of Ets-regulated target genes widens, so does their role in various pathological and physiological processes. Regulation of matrix degrading proteases by Ets factors in tumor invasion and metastasis is well established. Emerging evidence suggests that they may also play a role in the pathology of autoimmune diseases. Newly characterized Ets target genes such as tenascin-C and collagen type I suggest their role in diseases characterized by aberrant collagen deposition (fibrosis). Ets function is also critical in bone and cartilage development. There is increasing knowledge of the complex regulatory mechanisms involved in transcription of Ets target genes. Ets factors may function as activators or as repressors via association with specific cofactors depending on the promoter context. Signaling pathways can modulate the activation status of Ets factors and their transcriptional partners. Precise understanding of the role of Ets factors in the complex cellular network governing the expression of ECM proteins and the enzymes that degrade them will be a focus of future studies.

Breast tumour cell-induced down-regulation of type I collagen mRNA in fibroblasts

This study investigated the modulation of type I collagen gene expression in normal fibroblasts by breast tumour cells. Northern analysis of total RNA extracted from stages I, II and III breast tumour tissue revealed that collagen mRNA levels were elevated in stage I tumours compared to the adjacent normal breast tissues, whereas they were decreased in stages II and III breast tumours. This aberrant collagen gene expression was confirmed by non-radioactive RNA:RNA in situ hybridization analysis of 30 breast carcinomas which localized the production of type I collagen mRNA to the stromal fibroblasts within the vicinity of the tumour cells. In order to determine whether the tumour cells were directly responsible for this altered collagen production by the adjacent fibroblasts, breast tumour cell lines were co-cultured with normal fibroblasts for in vitro assessment of collagen and steady-state collagen RNA levels. Co-culture of tumour cells and normal fibroblasts in the same dish resulted in down-regulation of collagen mRNA and protein. Treatment of the fibroblasts with tumour-cell conditioned medium also resulted in decreased collagen protein levels but the mRNA levels, however, remained unaltered. These results suggested that the tumour cells either secrete a labile 'factor', or express a cell surface protein requiring direct contact with the fibroblasts, resulting in down-regulation of collagen gene expression. Modulation of the ECM is a common characteristic of invading tumour cells and usually involves increased production of collagenases by the tumour cells or stromal fibroblasts. This study showed that tumour cells were also able to modulate collagen mRNA production by stromal fibroblasts, which may facilitate tumour cell invasion and metastasis.

Characterization of type I collagen synthesis and maturation in uterine carcinosarcomas

BACKGROUND

Epithelial malignancies often induce an enhanced expression of interstitial collagens in the fibroblasts within the tumor tissue and the surrounding non-neoplastic stroma. In uterine carcinosarcomas (malignant mixed müllerian tumors [MMMTs]) both the stroma and the epithelium are malignant.

METHODS

In this investigation, both in situ hybridization and immunohistochemical staining were applied with two different antibodies that were capable of distinguishing between newly synthesized and mature, trivalently cross-linked Type I collagen to define Type I procollagen mRNA expression and the synthesis and maturation of the corresponding protein in MMMTs.

RESULTS

In the better differentiated parts of these tumors, in which anticytokeratins stained only clearly carcinomatous cells, Type I procollagen mRNA expression was limited to stromal fibroblasts; mature Type I collagen bundles were abundant and regular. In poorly differentiated areas, in which anticytokeratins stained only a few individual cells, Type I procollagen mRNA was expressed peculiarly by three morphologically different cell types. In addition to benign mesenchymal cells, Type I procollagen mRNA was present in atypical epithelial and mesenchymal cells. In these tumors, the collagen bundles close to the malignant cells were comprised of newly synthesized Type I collagen, with only little evidence of the presence of mature, fully cross-linked collagen.

CONCLUSIONS

These results strongly suggest that the undifferentiated cells of MMMTs are capable of producing their own stroma with irregularly arranged collagen bundles.

The extracellular matrix in skin tumor development-a morphological study

The development of cancer involves epithelial-stromal interactions. Alterations in the synthesis and deposition of type I and III collagens are related to the tumor morphology. Skin carcinogenesis in experimental animals provides a reliable model for the development of neoplasia. Ultraviolet (UV) irradiation is the main etiological factor for epidermal dysplasia and malignant tumors in man, but also for dermal degeneration. Non-neoplastic dermal changes and skin tumors induced by ultraviolet irradiation and 7,12-dimethylbenz(a)anthracene were investigated in various mouse strains with different susceptibilities to tumor formation. UVB irradiation resulted in an increased immunoreactivity of collagens in the dermis, in comparison with 7,12-dimethylbenz(a)anthracene. Increased synthesis and deposition of type I and III collagens were found in the stroma adjacent to benign alterations. In well-differentiated squamous cell carcinomas, a similar induction of collagen synthesis and deposition was observed. The destruction of fibrillary structures was more pronounced during the decrease of differentiation from moderately to poorly differentiated squamous cell carcinomas. Anaplastic carcinomas with spindle cell morphology displayed a delicate meshwork of reticular fibers and collagen III, and abnormal expression of mRNA for collagens in some malignant cells with epithelial characteristics. The underlying stroma reacts to the development of epithelial tumors in a reproducible way, which is related to the carcinogenic agent involved.