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

Emerging clinical applications in oncology for non-invasive multi- and hyperspectral imaging of cell and tissue autofluorescence

Hyperspectral and multispectral imaging of cell and tissue autofluorescence is an emerging technology in which fluorescence imaging is applied to biological materials across multiple spectral channels. This produces a stack of images where each matched pixel contains information about the sample's spectral properties at that location. This allows precise collection of molecularly specific data from a broad range of native fluorophores. Importantly, complex information, directly reflective of biological status, is collected without staining and tissues can be characterised in situ, without biopsy. For oncology, this can spare the collection of biopsies from sensitive regions and enable accurate tumour mapping. For in vivo tumour analysis, the greatest focus has been on oral cancer, whereas for ex vivo assessment head-and-neck cancers along with colon cancer have been the most studied, followed by oral and eye cancer. This review details the scope and progress of research undertaken towards clinical translation in oncology.

Quantitative Proteomic Analysis of Cervical Cancer Tissues Identifies Proteins Associated With Cancer Progression

BACKGROUND/AIM

To date, several proteomics studies in cervical cancer (CC) have focused mainly on squamous cervical cancer (SCC). Our study aimed to discover and clarify differences in SCC and CAD that may provide valuable information for the identification of proteins involved in tumor progression, in CC as a whole, or specific for SCC or CAD.

MATERIALS AND METHODS

Total protein extracts from 15 individual samples corresponding to 5 different CC tissue types were compared with a non-cancerous control group using bidimensional liquid chromatography-mass spectrometry (2D LC-MS/MS), isobaric tags for relative and absolute quantitation (ITRAQ), principal component analysis (PCA) and gene set enrichment analysis (GSEA).

RESULTS

A total of 622 statistically significant different proteins were detected. Exocytosis-related proteins were the most over-represented, accounting for 25% of the identified and quantified proteins. Based on the experimental results, reticulocalbin 3 (RCN3) and Ras-related protein Rab-14 (RAB14) were chosen for further downstream in vitro and vivo analyses. RCN3 was overexpressed in all CC tissues compared to the control and RAB14 was overexpressed in squamous cervical cancer (SCC) compared to invasive cervical adenocarcinoma (CAD). In the tumor xenograft experiment, RAB14 protein expression was positively correlated with increased tumor size. In addition, RCN3-expressing HeLa cells induced a discrete size increment compared to control, at day 47 after inoculation.

CONCLUSION

RAB14 and RCN3 are suggested as potential biomarkers and therapeutic targets in the treatment of CC.

MMP9 SNP and MMP SNP-SNP interactions increase the risk for ischemic stroke in the Han Hakka population

OBJECTIVES

To investigate the association of eight variants of four matrix metalloproteinase (MMP) genes with ischemic stroke (IS) and whether interactions among these single nucleotide polymorphisms (SNPs) increases the risk of IS.

METHODS

Among 547 patients with ischemic stroke and 350 controls, matrix-assisted laser desorption/ionization time of flight mass spectrometry was used to examine eight variants arising from four different genes, including MMP-1 (rs1799750), MMP-2 (rs243865, rs2285053, rs2241145), MMP-9 (rs17576), and MMP-12 (rs660599, rs2276109, and rs652438). Gene-gene interactions were employed using generalized multifactor dimensionality reduction (GMDR) methods.

RESULTS

The frequency of rs17576 was significantly higher in IS patients than in controls (p = .033). Logistic regression analysis revealed the AG and GG genotypes of rs17576 to be associated with a higher risk for IS, with the odds ratio and 95% confidence interval being 2.490 (1.251-4.959) and 2.494 (1.274-4.886), respectively. GMDR analysis showed a significant SNP-SNP interaction between rs17576 and rs660599 (the testing balanced accuracy was 53.70% and cross-validation consistency was 8/10, p = .0107). Logistic regression analysis showed the interaction between rs17576 and rs660599 to be an independent risk factor for IS with an odds ratio of 1.568 and a 95% confidence interval of 1.152-2.135.

CONCLUSION

An MMP-9 rs17576 polymorphism is associated with increased IS risk in the Han Hakka population and interaction between MMP-9 rs17576 and MMP-12 rs660599 is associated with increased IS risk as well.

Real-time polarization microscopy of fibrillar collagen in histopathology

Over the past two decades, fibrillar collagen reorganization parameters such as the amount of collagen deposition, fiber angle and alignment have been widely explored in numerous studies. These parameters are now widely accepted as stromal biomarkers and linked to disease progression and survival time in several cancer types. Despite all these advances, there has not been a significant effort to make it possible for clinicians to explore these biomarkers without adding steps to the clinical workflow or by requiring high-cost imaging systems. In this paper, we evaluate previously described polychromatic polarization microscope (PPM) to visualize collagen fibers with an optically generated color representation of fiber orientation and alignment when inspecting the sample by a regular microscope with minor modifications. This system does not require stained slides, but is compatible with histological stains such as H&E. Consequently, it can be easily accommodated as part of regular pathology review of tissue slides, while providing clinically useful insight into stromal composition.

Evaluation of immunohistopathological profile of tubular and solid canine mammary carcinomas

Breast cancer is the most common cancer in women, but the incidence of mammary carcinoma in female dogs is even higher than in humans. These two tumors have similarities that can be seen by its biological behavior, molecular genetic alterations, and histology. This suggest that female dogs can be an excellent model for preclinical oncological studies. And the mammary carcinoma most frequently found in this species is the tubular and solid carcinomas. The extracellular matrix (ECM) has an important role in the progression of these tumors. Because of that we proposed to evaluate the ECM components of these carcinomas through histology with specific stains such as Masson's Trichrome, Picrosirius Red and the technique of scanning electron microscopy. With that, we found the presence of collagen fibers in the tubular carcinoma and around its parenchyma. On the other hand, the solid carcinoma presented collagen fibers throughout the parenchyma and around each tumor cell. With the transmission electron microscopy, we observed the presence of mitochondrias and rough endoplasmic reticulum in both tumors. And finally, we evaluated the expression of proteins through the immunohistochemistry, in which we found a high expression of VEGF, PCNA, CK-18 and vimentin in solid carcinoma, and a positive mark in the tubular and solid carcinoma for collagen I, III and fibronectin. Thus, we demonstrated some differences in the ECM of these mammary carcinomas, allowing a better understanding of its histological characteristics, and these data may contribute to future studies about therapies focused on tumors ECM.

Association between matrix metalloproteinase family gene polymorphisms and risk of ischemic stroke: A systematic review and meta-analysis of 29 studies

BACKGROUND

Ischemic stroke (IS) is a complex and devastating vascular disease that has become one of the leading causes of disability and mortality worldwide. Several studies have shown the association between matrix metalloproteinase (MMP) family gene polymorphisms and IS. However, the results have been indecisive.

OBJECTIVE

To investigate the association between Matrix Metalloproteinase gene polymorphisms and risk of IS.

METHODS

A literature search for eligible candidate gene studies published before, 28 June 2017, was conducted in the PubMed, EMBASE, Cochrane and Google Scholar databases. The following combinations of main keywords were used: ('Matrix Metalloproteinase' or 'MMP' or 'Stromelysin-1' or 'Gelatinase b') AND ('ischemic stroke' or 'IS') AND ('single nucleotide polymorphism' or 'gene polymorphism' or 'SNP'). Fixed or random effects models were used to estimate the Pooled Odds ratio (OR) and 95% confidence interval (CI). Statistical analysis was carried out by using STATA version 13.0 software.

RESULTS

Total 29 studies were included in our meta-analysis. A significant association was observed for MMP-9 (-1562C/T) (OR 1.27; 95% CI 1.06 to 1.53; p value = 0.01) and MMP-12 (-1082 A/G) (OR 2.55; 95% CI 1.75 to 3.71; p value<0.001) gene polymorphisms and risk of IS. No significant association was found for any of the MMP-1(-1607 1G/2G), MMP-2 (-1306C/T) & (-735C/T) and MMP-3 (-1612 5A/6A) gene polymorphisms with the risk of IS.

CONCLUSION

Our meta-analysis suggests that MMP-9 (-1562C/T) and MMP-12 (-1082 A/G) gene polymorphisms could be a risk factor for IS while MMP-1 (-1607 1G/2G), MMP-2 (-1306C/T) & (-735C/T) and MMP-3 (-1612 5A/6A) have no association with the risk of causing IS. However, large prospective studies with sufficient power are required to validate our findings.

Evaluation of Collagen in Leukoplakia, Oral Submucous Fibrosis and Oral Squamous Cell Carcinomas Using Polarizing Microscopy and Immunohistochemistry

Objectives:

Picrosirius red and MMP are capable of degrading extracellular matrix proteins, expressed in lesions such as squamous cell carcinomas. The present study was undertaken with an aim to analyze and compare changes in collagen using Picrosirius red staining under polarizing microscopy and immunohistochemical staining using anti MMP-13 in samples of oral leukoplakia, oral submucous fibrosis and oral squamous cell carcinoma.

Materials and Methods:

A total of 70 slides were prepared and divided into 3 groups. Group I comprised 10 slides of normal gingival tissue, Group II 40 slides of potentially malignant disorders and Group III 20 slides of well differentiated oral squamous cell carcinoma. Half the slides for each group were stained with Picrosirius red stain and the remainder with antibodies to MMP-13.

Rerults:

In Group II, MMP-13 connective tissue expression was greater in OSMF as compared to leukoplakia. Group III showed elevated expression among 70% of cases. Picrosirius red staining in Group II cases, showed higher staining Yellow-Orange andGreen-Yellow mature fibers in OSMF than leukoplakia cases while in Group III, 50% OSCC cases showed Green-yellow stained immature thin fibers.

Conclusion:

In future, therapeutic measures targeted against MMP-13 may inhibit collagenolysis to some extent and delay spread of tumors. An easy and reliable method to determine the state of the stroma in such cases may be Picrosirius red staining with polarizing microscopy.

A Mathematical Model for the Onset of Avascular Tumor Growth in Response to the Loss of P53 Function

We present a mathematical model for the formation of an avascular tumor based on the loss by gene mutation of the tumor suppressor function of p53. The wild type p53 protein regulates apoptosis, cell expression of growth factor and matrix metalloproteinase, which are regulatory functions that many mutant p53 proteins do not possess. The focus is on a description of cell movement as the transport of cell population density rather than as the movement of individual cells. In contrast to earlier works on solid tumor growth, a model is proposed for the initiation of tumor growth. The central idea, taken from the mathematical theory of dynamical systems, is to view the loss of p53 function in a few cells as a small instability in a rest state for an appropriate system of differential equations describing cell movement. This instability is shown (numerically) to lead to a second, spatially inhomogeneous, solution that can be thought of as a solid tumor whose growth is nutrient diffusion limited. In this formulation, one is led to a system of nine partial differential equations. We show computationally that there can be tumor states that coexist with benign states and that are highly unstable in the sense that a slight increase in tumor size results in the tumor occupying the sample region while a slight decrease in tumor size results in its ultimate disappearance.

The Role of Matrix Metalloproteinase Polymorphisms in Ischemic Stroke

Stroke remains the fifth leading cause of mortality in the United States with an annual rate of over 128,000 deaths per year. Differences in incidence, pathogenesis, and clinical outcome have long been noted when comparing ischemic stroke among different ethnicities. The observation that racial disparities exist in clinical outcomes after stroke has resulted in genetic studies focusing on specific polymorphisms. Some studies have focused on matrix metalloproteinases (MMPs). MMPs are a ubiquitous group of proteins with extensive roles that include extracellular matrix remodeling and blood-brain barrier disruption. MMPs play an important role in ischemic stroke pathophysiology and clinical outcome. This review will evaluate the evidence for associations between polymorphisms in MMP-1, 2, 3, 9, and 12 with ischemic stroke incidence, pathophysiology, and clinical outcome. The role of polymorphisms in MMP genes may influence the presentation of ischemic stroke and be influenced by racial and ethnic background. However, contradictory evidence for the role of MMP polymorphisms does exist in the literature, and further studies will be necessary to consolidate our understanding of these multi-faceted proteins.

A novel role of annexin A2 in human type I collagen gene expression

The fibrillar collagen scaffold of the extracellular matrix provides a structural framework for cells in tissues and regulates intercellular communication; its disregulation has been associated with tumour development and progression. Previous work has shown that expression of type I collagen, the most abundant mammalian extracellular matrix protein, is decreased in chemically or virally transformed cells. This negative regulation could be mapped to a proximal COL1A2 promoter element spanning a CME (Collagen Modulating Element) site in SV40‐transformed human fibroblasts (SV‐WI38) that binds an unknown repressing protein. By magnetic bead pull‐down, we observed a multi‐protein complex bound to the CME with preference for single‐stranded over conventional double‐stranded DNA. MALDI‐TOF mass spectrometry of the CME‐binding protein complex revealed involvement of nuclear annexin A2 (AnxA2) which was increased in SV40‐transformed cells. Further EMSA analysis demonstrated that AnxA2 did not directly bind to the DNA but stabilised the complex and led to an increase in protein binding to the CME in SV‐WI38 but not untransformed WI38 cells. Knockdown of AnxA2 by siRNA increased type I collagen production in both WI38 and SV‐WI38 cells; however, these effects were not mediated at the transcriptional level. Rather, our data indicate a novel functional role of AnxA2 in the negative post‐transcriptional regulation of type I collagen synthesis in human fibroblasts. In SV40‐transformed cells, AnxA2 is accumulated at the proximal COL1A2 promoter region, suggesting close association with the transcriptional machinery that possibly facilitates binding to the emerging mRNA, eventually contributing to overall repression of type I collagen protein synthesis. J. Cell. Biochem. 116: 408–417, 2015. © 2014 The Authors. Journal of Cellular Biochemistry published by Wiley Periodicals, Inc.

Tumour cells down-regulate CCN2 gene expression in co-cultured fibroblasts in a Smad7- and ERK-dependent manner

Background

Recent studies have revealed that interactions between tumour cells and the surrounding stroma play an important role in facilitating tumour growth and invasion. Stromal fibroblasts produce most of the extracellular matrix components found in the stroma. The aim of this study was to investigate mechanisms involved in tumour cell-mediated regulation of extracellular matrix and adhesion molecules in co-cultured fibroblasts. To this end, microarray analysis was performed on CCD-1068SK human fibroblast cells after direct co-culture with MDA-MB-231 human breast tumour cells.

Results

We found that the expression of both connective tissue growth factor (CTGF/CCN2) and type I collagen was negatively regulated in CCD-1068SK fibroblast cells under direct co-culture conditions. Further analysis revealed that Smad7, a known negative regulator of the Smad signalling pathway involved in CCN2 promoter regulation, was increased in directly co-cultured fibroblasts. Inhibition of Smad7 expression in CCD-1068SK fibroblasts resulted in increased CCN2 expression, while Smad7 overexpression had the opposite effect. Silencing CCN2 gene expression in fibroblasts led, in turn, to a decrease in type I collagen mRNA and protein levels. ERK signalling was also shown to be impaired in CCD-1068SK fibroblasts after direct co-culture with MDA-MB-231 tumour cells, with Smad7 overexpression in fibroblasts leading to a similar decrease in ERK activity. These effects were not, however, seen in fibroblasts that were indirectly co-cultured with tumour cells.

Conclusion

We therefore conclude that breast cancer cells require close contact with fibroblasts in order to upregulate Smad7 which, in turn, leads to decreased ERK signalling resulting in diminished expression of the stromal proteins CCN2 and type I collagen.

Second harmonic generation reveals matrix alterations during breast tumor progression

Alteration of the extracellular matrix in tumor stroma influences efficiency of cell locomotion away from the primary tumor into surrounding tissues and vasculature, thereby affecting metastatic potential. We study matrix changes in breast cancer through the use of second harmonic generation (SHG) of collagen in order to improve the current understanding of breast tumor stromal development. Specifically, we utilize a quantitative analysis of the ratio of forward to backward propagating SHG signal (F/B ratio) to monitor collagen throughout ductal and lobular carcinoma development. After detection of a significant decrease in the F/B ratio of invasive but not in situ ductal carcinoma compared with healthy tissue, the collagen F/B ratio is investigated to determine the evolution of fibrillar collagen changes throughout tumor progression. Results are compared with the progression of lobular carcinoma, whose F/B signature also underwent significant evolution during progression, albeit in a different manner, which offers insight into varying methods of tissue penetration and collagen manipulation between the carcinomas. This research provides insights into trends of stromal reorganization throughout breast tumor development.

Native fluorescence spectra of human cancerous and normal breast tissues analyzed with non-negative constraint methods

The native fluorescence spectra of human cancerous and normal breast tissues were investigated using the selected excitation wavelength of 340 nm to excite key building block molecules, such as reduced nicotinamide adenine dinucleotide (NADH), collagen, and flavin. The measured emission spectra were analyzed using a non-negative constraint method, namely multivariate curve resolution with alternating least-squares (MCR-ALS). The results indicate that the biochemical changes of tissue can be exposed by native fluorescence spectra analysis. The MCR-ALS-extracted components corresponding to the key fluorophores in breast tissue, such as collagen, NADH, and flavin, show differences of relative contents of fluorophores in cancerous and normal breast tissues. This research demonstrates that the native fluorescence spectroscopy measurements are effective for detecting changes of fluorophores composition in tissues due to the development of cancer. Native fluorescence spectroscopy analyzed by MCR-ALS may have the potential to be a new armamentarium.

Anti-matrix metalloproteinase-9 DNAzyme decreases tumor growth in the MMTV-PyMT mouse model of breast cancer

INTRODUCTION

Despite continued improvements in diagnosis, surgical techniques, and chemotherapy, breast cancer patients are still overcome by cancer metastasis. Tumor cell proliferation, invasion and metastasis are mediated, at least in part, through degradation of basement membrane by neutral matrix metalloproteinases (MMP) produced by tumor and stromal cells. Evidence suggests that MMP-9 plays a significant role in breast tumor cell invasion and metastasis. DNAzymes or catalytic oligonucleotides are new classes of gene targeting molecules that bind and cleave a specific mRNA, resulting in decreased protein expression.

METHODS

The application of anti-MMP-9 DNAzyme (AM9D) for the treatment of primary and metastatic breast cancer was evaluated in vitro and in vivo using MDA-MB-231 cells and the MMTV-PyMT transgenic breast cancer mouse model. Spontaneously developed mammary tumors in MMTV-PyMT transgenic mice were treated intratumorally with naked AM9D, once a week for 4 weeks. The stability of DNAzyme was determined in vitro and in vivo using fluorescently labeled DNAzyme.

RESULTS

AM9D specifically inhibited expression of MMP-9 in MDA-MB-231 cells resulting in reduced invasive property of these cells by 43%. Weekly intratumoral treatment of spontaneously developed mammary tumors in MMTV-PyMT transgenic mice was sufficient to significantly reduce the rate of tumor growth and final tumor load in a dose dependent and statistically significant manner (P < 0.05). This decrease in tumor growth was correlated with decreased MMP-9 protein production within the treated tumor tissues. Tumors treated with AM9D were also less vascularized and contained more apoptotic cells compared to control and untreated tumors.

CONCLUSIONS

These results show that targeting and down regulation of MMP-9 by AM9D could prove useful as a therapy against breast carcinoma tumor growth and invasion.

Stokes shift spectroscopy highlights differences of cancerous and normal human tissues

The Stokes shift spectroscopy (S3) offers a simpler and better way to recognize spectral fingerprints of fluorophores in complex mixtures. The efficiency of S3 for cancer detection in human tissue was investigated systematically. The alterations of Stokes shift spectra (S3) between cancerous and normal tissues are due to the changes of key fluorophores, e.g., tryptophan and collagen, and can be highlighted using optimized wavelength shift interval. To our knowledge, this is the first time to explicitly disclose how and why S3 is superior in comparison with other conventional spectroscopic techniques.

Proteomic profiling of infiltrating ductal carcinoma reveals increased cellular interactions with tissue microenvironment

Progression of invasive carcinoma involves the deregulation of molecular signaling pathways that results in the acquisition of oncogenic phenotypes. Functional enrichment analysis allows for the identification of deregulated pathways from omics scale expression data. Given the importance of post-transcriptional regulatory mechanisms on protein expression and function, identification of deregulated pathways on the basis of protein expression data is likely to provide new insights. In this study, we have developed methods for label-based mass spectrometry in a large number of samples and applied these methods toward identification and quantification of protein expression in samples of infiltrating ductal carcinoma, benign breast growths, and normal adjacent tissue. We identified 265 proteins with differential expression patterns in infiltrating ductal carcinoma relative to benign growths or normal breast tissue. Analysis of the differentially expressed proteins indicated the deregulation of signaling pathways related to proliferation, invasion and metastasis, and immune response. Our approach provides complementary information to gene expression microarray data and identifies a number of deregulated molecular signaling pathways indicative of breast cancer progression that may enable more accurate, biologically relevant diagnoses and provide a stepping stone to personalized treatment.

A role for Tbx2 in the regulation of the alpha2(1) collagen gene in human fibroblasts

The T-box gene family encodes highly conserved transcription factors that play important roles in embryonic development and have been implicated in carcinogenesis. One member of the family, Tbx2, is generally regarded as a transcriptional repressor but appears to be capable of functioning as an activator depending on the cellular context. This study shows that Tbx2 is expressed in normal human fibroblasts but is drastically reduced in several transformed fibroblast cell lines. This pattern of Tbx2 expression correlated with that observed for the human alpha2(1) collagen gene (COL1A2). Interestingly, stable expression of transfected Tbx2 in transformed fibroblast cell lines further reduces expression of the human endogenous COL1A2 gene. This ability of Tbx2 to repress the human COL1A2 gene was confirmed in luciferase reporter assays and shown to be independent of the consensus T-box binding element.

A mathematical model for the onset of avascular tumor growth in response to the loss of p53 function

We present a mathematical model for the formation of an avascular tumor based on the loss by gene mutation of the tumor suppressor function of p53. The wild type p53 protein regulates apoptosis, cell expression of growth factor and matrix metalloproteinase, which are regulatory functions that many mutant p53 proteins do not possess. The focus is on a description of cell movement as the transport of cell population density rather than as the movement of individual cells. In contrast to earlier works on solid tumor growth, a model is proposed for the initiation of tumor growth. The central idea, taken from the mathematical theory of dynamical systems, is to view the loss of p53 function in a few cells as a small instability in a rest state for an appropriate system of differential equations describing cell movement. This instability is shown (numerically) to lead to a second, spatially inhomogeneous, solution that can be thought of as a solid tumor whose growth is nutrient diffusion limited. In this formulation, one is led to a system of nine partial differential equations. We show computationally that there can be tumor states that coexist with benign states and that are highly unstable in the sense that a slight increase in tumor size results in the tumor occupying the sample region while a slight decrease in tumor size results in its ultimate disappearance.

The Shaping of a Polyvalent and Highly Individual T-Cell Repertoire in the Bone Marrow of Breast Cancer Patients

We analyzed the T-cell repertoires from the bone marrow of 39 primary operated breast cancer patients and 11 healthy female donors for the presence and frequencies of spontaneously induced effector/memory T lymphocytes with peptide-HLA-A2-restricted reactivity against 10 breast tumor-associated antigens (TAA) and 3 normal breast tissue–associated antigens by short-term IFN-γ enzyme-linked immunospot (ELISpot) analysis. Sixty-seven percent of the patients recognized TAAs with a mean frequency of 144 TAA reactive cells per 106 T cells. These patients recognized simultaneously an average of 47% of the tested TAAs. The T-cell repertoire was highly polyvalent and exhibited pronounced interindividual differences in the pattern of TAAs recognized by each patient. Strong differences of reactivity were noticed between TAAs, ranging from 100% recognition of prostate-specific antigenp141-149 to only 25% recognition of MUC1p12-20 or Her-2/neup369-377. In comparison with TAAs, reactivity to normal breast tissue–associated antigens was lower with respect to the proportions of responding patients (30%) and recognized antigens (27%), with a mean frequency of only 85/106 T cells. Healthy individuals also contained TAA-reactive T cells but this repertoire was more restricted and the frequencies were in the same range as T cells reacting to normal breast tissue–associated antigens. Our data show a highly individual T-cell repertoire for recognition of TAAs in breast cancer patients. This has potential relevance for T-cell immune diagnostics, for tumor vaccine design, and for predicting immune responsiveness. (Cancer Res 2006; 66(16): 8258-65)

Secretory protein enrichment and analysis: an optimized approach applied on cancer cell lines using 2D LC-MS/MS

Reliable methods for profiling secretory proteins are highly desirable for the identification of biomarkers of disease progression. Secreted proteins are often masked by high amounts of protein supplements in the culture medium. We have developed an efficient method for the enrichment and analysis of the secretome of different cancer cell lines, free of essential contaminants. The method is based on the optimization of cell incubation conditions in protein-free medium. Secreted proteins are concentrated and fractionated using a reversed-phase tC2 Sorbent, followed by peptide mass fingerprinting for protein identification. An average of 88 proteins were identified in each cancer cell line, of which more than 76% are known to be secreted, possess a signal peptide or a transmembrane domain. Given the importance of secreted proteins as a source for early detection and diagnosis of disease, this approach may help to discover novel candidate biomarkers with potential clinical significance.

Differential coexpression analysis using microarray data and its application to human cancer

MOTIVATION

Microarrays have been used to identify differential expression of individual genes or cluster genes that are coexpressed over various conditions. However, alteration in coexpression relationships has not been studied. Here we introduce a model for finding differential coexpression from microarrays and test its biological validity with respect to cancer.

RESULTS

We collected 10 published gene expression datasets from cancers of 13 different tissues and constructed 2 distinct coexpression networks: a tumor network and normal network. Comparison of the two networks showed that cancer affected many coexpression relationships. Functional changes such as alteration in energy metabolism, promotion of cell growth and enhanced immune activity were accompanied with coexpression changes. Coregulation of collagen genes that may control invasion and metastatic spread of tumor cells was also found. Cluster analysis in the tumor network identified groups of highly interconnected genes related to ribosomal protein synthesis, the cell cycle and antigen presentation. Metallothionein expression was also found to be clustered, which may play a role in apoptosis control in tumor cells. Our results show that this model would serve as a novel method for analyzing microarrays beyond the specific implications for cancer.

Three-dimensional coculture of endometrial cancer cells and fibroblasts in human placenta derived collagen sponges and expression matrix metalloproteinases in these cells

OBJECTIVE

Collagen gel constitutes a valuable tool for the study of cell-matrix interactions; however, it is sometimes difficult to use the gel, in which tumor and stromal cells are cocultured, for immunohistochemistry, because it is easily broken during the process of fixation and embedding in paraffin, especially after long-term culture.

METHODS

To examine the interaction between endometrial cancer cells and fibroblasts in tumor invasion, we carried out three-dimensional (3-D) coculture of various endometrial cancer cell lines and fibroblasts in human placenta derived collagen sponges and analyzed the expression and localization of matrix metalloproteinases (MMP) and plasminogen activators (PA) in these cells by immunohistochemistry.

RESULTS

After 4 weeks of culture on the collagen sponges, endometrial cancer cells composed stratiform or glandular structures on the layer of extracellular matrix, which was composed from fibloblasts and extracellular matrix. Compared to Ishikawa cells, which were rarely invasive, HEC-1A and HEC-1BE and cocultured fibroblasts showed high invasiveness and strong expression of some proteins. In cell line HEC-1BE, MMP-1, -7, and -9, MT1-MMP, tissue inhibitors of metalloproteinases 2, and uPA showed intensive staining in both cancer cells and fibroblasts by immunohistochemistry. HEC-1A cells and cocultured fibroblasts showed expression patterns similar to those of HEC-1BE.

CONCLUSION

These results suggested that expression of MMPs and uPA was accelerated in fibroblasts surrounded by cancer cells. We believe that our 3-D coculture system has merit in that the interaction between cancer cells and stromal cells can be visually analyzed by immunohistochemistry and that experiments for a long period, at least 2 weeks, are possible. Furthermore, it is expected that some animal, e.g., nude mouse, experiments can be replaced by experiments using this culture system.

Infrequent somatic deletion of the 5' region of the COL1A2 gene in oesophageal squamous cell cancer patients

Oesophageal squamous cell cancer is the leading cause of cancer death amongst African males in South Africa. DNA was isolated from normal and tumour biopsies of the oesophagi of 33 African patients with squamous cell carcinoma of the oesophagus and was analysed with two dinucleotide repeat polymorphisms, a GT repeat sequence in the first intron, and a CA repeat in the promoter of the human alpha2(I) procollagen gene (COL1A2), using the polymerase chain reaction (PCR). Normal and tumour DNAs from each individual were compared to identify changes present in the tumour DNA, but absent in normal DNA. Twenty two cases were informative (heterozygous) for the promoter polymorphism and 24 cases were informative for the intronic polymorphism. Loss of heterozygosity (LOH) was seen in 2/22 (9.1%) for the promoter and 3/24 (12.5%) for the intronic polymorphism. These changes involved a total of three patients: two patients displayed the lost allele incorporating both the CA repeat and GT repeat loci; the third patient revealed LOH at the intronic polymorphism, but was non-informative (homozygous) for the promoter polymorphism. Deletions within the procollagen genes may represent an as yet unrecognised but rare event in the multistep process of carcinogenesis.

In situ production of gamma interferon, interleukin-4, and tumor necrosis factor alpha mRNA in human lung tuberculous granulomas

Human tuberculous granulomas from five adults undergoing surgery for hemoptysis were analyzed by nonradioactive in situ hybridization for tumor necrosis factor alpha (TNF-alpha), gamma interferon (IFN-gamma), and interleukin-4 (IL-4) gene expression. All of the patients produced TNF-alpha mRNA. Three patients stained positive for both IFN-gamma and IL-4 mRNA; the other two stained positive for IFN-gamma but not IL-4 mRNA. Heterogeneity between the granulomas was observed in those patients staining positive for both IFN-gamma and IL-4 mRNA; these patients exhibited granulomas having IFN-gamma and not IL-4 mRNA as well as granulomas positive for both cytokine mRNAs. There was no evidence of caseation in these granulomas, and the cytokine patterns may represent events in the evolution of the granuloma. However, in those granulomas exhibiting caseous necrosis, very little IFN-gamma or IL-4 mRNA was observed, implying that progression of the granuloma is accompanied by a down regulation of T-cell responses. TNF-alpha mRNA expression was highest in patients with both IFN-gamma and IL-4 mRNA. Populations of CD68 positive macrophage-like cells within the granulomas produce mRNA for TNF-alpha, IFN-gamma, and IL-4. This implies that macrophages within the tuberculous granuloma may not be dependent on T-cell cytokines for modulation of their function but may be able to regulate their own activation state and that of the surrounding T cells. These findings have implications on the delivery of immunotherapies to patients with tuberculosis.