67-kDa laminin-receptor expression adds prognostic information to intra-tumoral microvessel density in node-negative breast cancer

Decoding the mystery of MMTV-like virus and its relationship with breast cancer metastasis

BACKGROUND

MMTV causes mammary tumors in mice, and it is associated with invasive and aggressive forms of breast cancer in humans. However, the underlying mechanisms are yet unknown. We aimed to determine the MMTV-like virus (MMTV-LV) association with histological types of breast cancer, nodal involvement, and metastasis.

METHODS

First, 105 breast cancer biopsies and 15 disease-free biopsies were collected. Details of clinicopathological characteristics were retrieved from patients' records. The status of MMTV-LV was already known for these biopsy samples. Associations of MMTV-LV prevalence with LNM status and metastatic history were determined. Next, quantitative PCR (qPCR) was used to quantify env gene mRNA in biopsies positive for MMTV-LV. Expression of the env gene was compared against different histopathological types of mammary tumor, LNM status, and metastasis by performing Ordinary One Way ANOVA followed by Tukey's multiple comparisons test.

RESULTS

MMTV-LV prevalence was found to have no significant association with LNM or metastatic history. As compared to normal control, expression of the env gene was significantly higher (>2.8 folds) in invasive samples (P-value: < 0.01). Expression was also higher (3.28 and 2.89 folds) in patient samples with LNM (P-value: 0.0006) or metastatic history (P-value: < 0.0001), respectively.

CONCLUSION

We conclude that MMTV-LV prevalence is not associated with LNM status or breast cancer metastasis; samples with invasive phenotypes, nodal involvement, and metastasis exhibit significantly higher expression of the MMTV-like env gene.

Correlation between Laminin and Cathepsin D Expressions in Breast Carcinoma

Aims and Background

Laminin is a major glycoprotein component of basement membrane which is an important barrier to tumor cells which must be breached before metastatic spread can occur. Proteolytic enzymes play an important role in mediating the passage of cancer cells through the basement membrane(BM) and extracellular matrix. We have compared the patterns of laminin and cathepsin D (CD) expressions in a range of benign and malignant breast lesions to better understand the process of tumor progression.

Methods

One hundred and sixty-two cases of breast samples comprising 18 fibroadenomas, 22 cases of fibrocystic disease, 96 cases of invasive ductal carcinoma and 26 carcinomas with intraductal components were evaluated for laminin and cathepsin D expressions by immunohistochemical staining.

Results

The prevalence of CD positivity in both neoplastic and stromal cell components were significantly higher in higher histological grade tumors compared to lower grades (P <0.01). Various severity of BM disruption correlated with histological grade of the carcinomas (P <0.001). There was a negative correlation between the laminin expression and CD presence.

Conclusions

It was confirmed that in a process of cancer cell invasion and metastasis, it could be necessary with the basement membrane disruption by proteinase secreted by cancer cells and especially by stroma cells of cancer.

Cellular and Molecular Changes in MNU-Induced Breast Tumours Injected with PF4 or bFGF

Background: Angiogenic activity has been considered to reflect important molecular events during breast tumour development. The present study concerned cellular and molecular changes of MNU-induced breast tumours subjected to promotion and suppression of angiogenesis. Methods: Female Sprague Dawley rats at the age of 21 days received MNU at the dose 70 mg/kg of body weight by intraperitoneal injection. Three months post-carcinogen initiation, mammary tumours were palpated and their growth was monitored. When the tumour diameter reached 1.0 ± 0.05 cm, rats were given bFGF or PF4 intratumourally at a dose of 10 μg/tumour. Entire palpable tumour were subsequently excised and subjected to histology examination, IHC staining, and RT-PCR. Results: No critical morphological changes were observed between pro-angiogenic factor, bFGF, and control groups. However, increase of tumour size with more necrotic and diffuse areas was notable in tumours after anti-angiogenic PF4 intervention. ER and PR mRNA expression was significantly up- and down-regulated in bFGF and PF4 groups, respectively. The trends were significantly associated with peri- and intratumoural MVD counts. However, irrespective of whether we promoted or inhibited angiogenesis, the expression of EGFR and ERBB2 continued to be significantly increased but this was not significantly associated with the MVD score. No significant differences in E-cadherin and LR gene expression were noted between intervention and control groups. Conclusion: ER and PR receptor expression shows consistent responses when tumour angiogenesis is manipulated either positively or negatively. Our study adds to current understanding that not only do we need to target hormonal receptors, as presently practiced, but we also need to target endothelial receptors to successfully treat breast cancer.

In vitro inhibition of angiogenesis by antibodies directed against the 37kDa/67kDa laminin receptor

The 37kDa/67kDa laminin receptor (LRP/LR) is a central receptor mediating interactions between tumour cells and the basement membrane and is thereby a key player in adhesion and invasion, essential processes in metastatic cancer. To affect continued tumour growth, tumours induce angiogenesis for the constant delivery of nutrients and oxygen. This study aims to determine the blocking effect of the anti-LRP/LR specific antibody, W3 on the angiogenic potential of HUVE (human umbilical vein endothelial) cells. Flow cytometric analysis revealed that 97% of HUVE cells display cell surface LRP/LR. An angiogenesis assay was conducted employing HUVE cells seeded on the basement membrane reconstituent Matrigel™ supplemented with the pro-angiogenic factor vascular endothelial growth factor (VEGF). Post 18h incubation at 37°C tubular structures, namely tube lengths were assessed. Treatment of established tubular structures with 100 µg/ml anti-LRP/LR specific antibody completely blocked angiogenesis. Our findings suggest a central role of the 37kDa/67kDa LRP/LR in tube formation and recommends anti-LRP/LR specific antibodies as potential therapeutic tools for treatment of tumour angiogenesis.

Comprehensive proteomic analysis of nonintegrin laminin receptor interacting proteins

Human nonintegrin laminin receptor is a multifunctional protein acting as an integral component of the ribosome and a cell surface receptor for laminin-1. The laminin receptor is overexpressed in several human cancers and is also the cell surface receptor for several viruses and pathogenic prion proteins, making it a pathologically significant protein. This study focused on the proteomic characterization of laminin receptor interacting proteins from Mus musculus. The use of affinity chromatography with immobilized recombinant laminin receptor coupled with mass spectrometry analysis identified 45 proteins with high confidence. Following validation through coimmunoprecipitation, the proteins were classified based on predicted function into ribosomal, RNA processing, signal transduction/metabolism, protein processing, cytoskeleton/cell anchorage, DNA/chromatin, and unknown functions. A significant portion of the identified proteins is related to functions or localizations previously described for laminin receptor. This work represents a comprehensive proteomic approach to studying laminin receptor and provides an essential stepping stone to a better mechanistic understanding of this protein's diverse functions.

Anti-LRP/LR-specific antibody IgG1-iS18 significantly reduces adhesion and invasion of metastatic lung, cervix, colon and prostate cancer cells

The 37-kDa/67-kDa laminin receptor [laminin receptor precursor/high-affinity laminin receptor (LRP/LR)] is thought to play a major role in invasion and adhesion, key components of metastatic cancer. Lung cancer, cervical cancer, colon cancer and prostate cancer are among the top 10 cancer types worldwide. Here, we report that LRP/LR levels on the surface of lung cancer cells, cervical cancer cells, colon cancer cells and prostate cancer cells are significantly increased compared to non-tumorigenic fibroblasts. Adhesion of lung cancer cells, cervical cancer cells, colon cancer cells and prostate cancer cells to laminin-1 is significantly reduced, employing the anti-LRP/LR-specific antibody IgG1-iS18. Invasion of these cell lines into the Matrigel™ matrix was significantly impeded with IgG1-iS18. The Pearson's correlation coefficient proves a correlation between LRP/LR cell-surface levels and invasion potential, as well as adhesion and invasion, respectively. Our findings suggest that IgG1-iS18 antibody might act as alternative therapeutic tool for treatment of various metastatic cancer types.

The role of elastin peptides in modulating the immune response in aging and age-related diseases

It is now well accepted that aging is associated with the occurrence of a low-grade inflammation called Inflamm-aging. This leads to the imbalance between the various mediators of the inflammatory response in favour of the pro-inflammatory response represented by pro-inflammatory cytokines and oxidative stress. The question that arises, and is still under investigation, what is the origin of the driving force leading to these changes. One of the current hypotheses is that chronic stimulation of the immune system contributes to the pro-inflammatory shift. The chronic stimulation can be of viral origin such as cytomegalovirus, from tumor antigens or from other sources such as the extracellular matrix, especially from elastin fibres and collagens. Aging and various inflammatory diseases such as atherosclerosis, abdominal aortic aneurysms, chronic obstructive pulmonary diseases (COPD), cancer and type 2 diabetes are characterized by the destruction of elastin fibers and the consequent generation of elastin peptides which are biologically active. This review will describe the putative contribution of elastin peptides to inflamm-aging and extend on their role on immunosenescence, as well as on age-associated chronic inflammatory diseases.

Angiogenesis: a prognostic determinant in pancreatic cancer?

Angiogenesis has been associated with disease progression in many solid tumours, however the statement that tumours need angiogenesis to grow, invade and metastasise seems no longer applicable to all tumours or to all tumour subtypes. Prognostic studies in pancreatic cancer are conflicting. In fact, pancreatic cancer has been suggested an example of a tumour in which angiogenesis is less essential for tumour progression. The aim of the present study was therefore to measure angiogenesis in two anatomically closely related however prognostically different types of pancreatic cancer, pancreatic head and periampullary cancer, and investigate its relation with outcome. Vessels were stained by CD31 on original paraffin embedded tissue from 206 patients with microscopic radical resection (R0) of pancreatic head (n=98) or periampullary cancer (n=108). Angiogenesis was quantified by microvessel density (MVD) and measured by computerised image analysis of three randomly selected fields and investigated for associations with recurrence free survival (RFS), cancer specific survival (CSS), overall survival (OS) and conventional prognostic factors. MVD was heterogeneous both between and within tumours. A higher MVD was observed in periampullary cancers compared with pancreatic head cancers (p<.01). Furthermore, MVD was associated with lymph node involvement in pancreatic head (p=.014), but not in periampullary cancer (p=.55). Interestingly, MVD was not associated with RFS, CSS or with OS. In conclusion, angiogenesis is higher in periampullary cancer and although associated with nodal involvement in pancreatic head cancer, pancreatic cancer prognosis seems indeed angiogenesis independent.

Chapter 14. Measuring intratumoral microvessel density

For a tumor to grow beyond a limited volume of 1-2 mm(3), the tumor cells must not only proliferate, but they must be able to induce the growth of new capillary blood vessels from the host. As early as 1971, it was proposed that tumor growth was dependent on angiogenesis; and, that tumor cells and blood vessels composed a highly integrated ecosystem, that endothelial cells could be switched from a resting state to one of rapid growth by a diffusible signal from tumor cells, and that anti-angiogenesis may become an effective anti-cancer therapy. Indeed, now there is considerable indirect and direct evidence to show that tumor growth is angiogenesis dependent, that tumor cells can produce diffusible angiogenic regulatory molecules, and that angiogenesis inhibitors can slow or prevent tumor growth, and that angiogenesis is a relevant target for anti-cancer therapy. Measuring intratumoral microvessel density (iMVD) in vascular "hot spots" has been shown to correlate with aggressive tumor behavior. This chapter reviews the techniques available for measuring iMVD.

67-kDa Laminin Receptor in Human Laryngeal Squamous Cell Carcinoma

OBJECTIVES/HYPOTHESIS

Abnormal interaction of epithelial cells with laminin component of basement membrane may account for altered biological behavior of cells, influencing proliferation, adhesion, and motility. In the current study, we investigated the role of 67-kDa laminin receptor (67LR), a high affinity receptor for laminin, in aggressiveness of laryngeal squamous cell carcinoma.

METHODS

Thirty paraffin-embedded specimens and 20 fresh tissues of patients with laryngeal squamous cell carcinoma were analyzed using immunohistologic and reverse-transcriptase polymerase chain reaction techniques, respectively. Expression of 67LR on the surface of AMC-HN-8 cells was examined by flow cytometry. The effect of 67LR monoclonal antibody (MLuC5) on the adhesive and invasive abilities of AMC-HN-8 cells was determined by adherence and invasion inhibition assay in vitro.

RESULTS

Both at the mRNA and protein level, laryngeal carcinoma cells expressed higher level of 67LR than normal epithelial cells (P < .01). The expression of 67LR correlated inversely with differentiation extent of tumor (P < .05). 67LR level was significantly increased in patients with lymph node metastases than those without lymph node involvement (P < .05). Flow cytometry showed 80.9 +/- 0.9% of AMC-HN-8 cells expressed 67LR. After 60 minutes and 120 minutes of incubation, MluC5 induced 57.1 +/- 3.6% and 63.2 +/- 2.8% inhibition of adhesion, respectively. The invasive ability of AMC-HN-8 cells to matrigel was reduced by MLuC5.

CONCLUSIONS

Laryngeal carcinoma cells over-expressing 67LR have a stronger aggressive potential, which might make 67LR a promising target for the treatment of metastatic tumor.

Increasing evidence for a human breast carcinoma virus with geographic differences

BACKGROUND

An early immunologic study suggesting that a virus similar to the mouse mammary tumor virus (MMTV) was associated highly with breast carcinoma in Tunisian patients, compared with patients in the United States, led the authors to examine different breast carcinoma populations by using more current molecular techniques.

METHODS

Thirty-nine paraffin blocks were selected for sequencing of the 250-base pair segment of the MMTV from patients with breast carcinoma who were seen and treated at the Institut Salah Azaiz in Tunisia. Fifteen of those blocks were examined under code by a second laboratory, which used a different methodology and was blinded to the results of the first laboratory, and 14 blocks were analyzed successfully.

RESULTS

The comparison of Tunisian patients and patients from other countries clearly showed a significantly higher proportion of tumors with MMTV-like sequences in the Tunisian series of patients. There was complete reproducibility of data between the two laboratories. Using the results from the first laboratory and similar studies from the literature, detection of the MMTV-like env gene sequence showed an important geographic pattern with a significantly higher percentage of positive patients with breast carcinoma in Tunisia (74%) compared with patients with breast carcinoma in the United States (36%), Italy (38%), Australia (42%), Argentina (31%), and Vietnam (0.8%)

CONCLUSIONS

The findings provided increased evidence for a human breast carcinoma virus with geographic differences in prevalence. The geographic differences were compatible with studies of MMTV in wild mice; thus, the data were plausible biologically.

Microvessel density as a prognostic factor in women with breast cancer: a systematic review of the literature and meta-analysis

We performed a meta-analysis of all 87 published studies linking intratumoral microvessel density (MVD), reflecting angiogenesis, to relapse-free survival (RFS) and overall survival (OS). With median MVD as cutoff, MVD impact was measured by risk ratio (RR) between the two survival distributions. Seventeen studies did not mention survival data or fit inclusion criteria. Twenty-two were multiple publications of the same series, leaving 43 independent studies (8936 patients). MVD was assessed by immunohistochemistry, using antibodies against factor VIII (27 studies; n = 5262), CD31 (10 studies; n = 2296), or CD34 (8 studies; n = 1726). MVD might be a better prognostic factor when assessed by CD31 or CD34 versus factor VIII (P = 0.11). For RFS, statistical calculations were performed in 25 studies (6501 patients). High MVD significantly predicted poor survival [RR = 1.54 for RFS and OS with the same 95% confidence interval (CI), 1.29-1.84]. Twenty-two studies analyzed separately lymph node-negative patients (n = 3580), for whom predictors of poor survival are requested. This latter meta-analysis included 15 studies for RFS (2727 patients) and 11 for OS (1926 patients). High MVD significantly predicted poor survival [RR = 1.99 for RFS (95% CI, 1.33-2.98) and RR = 1.54 for OS (95% CI, 1.01-2.33)]. Between-study variations could result from patient selection criteria, techniques to stain and count microvessels, and cutoff selection. MVD was a significant although weak prognostic factor in women with breast cancer. Standardization of MVD assessment is needed.

Overexpression of c-erbB-2 is related to a higher expression of vascular endothelial growth factor (VEGF) and constitutes an independent prognostic factor in primary node-positive breast cancer after adjuvant systemic treatment

The aim of this study was to investigate possible associations between the expression of c-erbB-2 and the angiogenic factors vascular endothelial growth factor (VEGF), basic fibroblast growth factor (bFGF), p53 status, routine breast cancer prognostic factors and survival. Expression of c-erbB-2, VEGF, bFGF, and p53 protein was determined with an enzyme-linked immunosorbent assay (ELISA) in 656 patients with primary breast cancer (median follow-up time of 83 months). In 60 cases, we also used immunohistochemistry (IHC) for c-erbB-2 evaluation, to be used as a reference for the ELISA. Overexpression of c-erbB-2 was significantly related to a higher expression of VEGF, lower bFGF content, negative steroid receptor status, and a high S-phase fraction. In multivariate analysis, c-erbB-2 was an independent prognostic factor for relapse-free survival (RFS) and overall survival (OS) in all patients, and in node-positive patients, irrespective of the adjuvant systemic therapy. Combined survival analyses regarding c-erbB-2 and VEGF yielded additional prognostic information.

Prognostic Significance of Laminin, Laminin Receptor, and Bone Marrow Micrometastases in Breast Cancer Patients

Laminin is a basement membrane glycoprotein implicated in a large number of biologic activities of cancer progression, many of which are mediated by the presence of the laminin receptor (67LR) on the cell membrane. We studied the correlations of laminin and its receptor with standardized and new prognostic factors (including bone marrow micrometastases) in a series of 112 patients with operable breast cancers. Laminin-positive cells were detected in 60% of the tumors and 67LR-positive cells in 55%; both were present in 35% of the cases. No association was found between laminin or 67LR positivity and pathologic tumor size, pathologic nodal status, grading, Ki-67, estrogen receptor status, progesterone receptor status, or bone marrow micrometastases. The only statistically significant association was with menopausal status and age, with a higher percentage of 67LR-positive tumors among premenopausal and younger patients. The median follow-up was approximately 7 years. The prognosis of disease-free survival was similar in the laminin-positive and laminin-negative subjects but was significantly better in 67LR-negative patients; there were no significant differences in overall survival. The prognostic role of laminin and 67LR in disease-free survival and overall survival varied according to nodal status. In the absence of nodal involvement, the risk of relapse (and death) was greater in the patients who were positive for laminin, 67LR, or both than in those who were negative for laminin, 67LR, or both; in the case of 4 or more involved nodes, the prognostic role of laminin and 67LR was reversed. These results did not change after adjustment for age, menopausal status, tumor status, nodal status, grading, or bone marrow micrometastases.

Prognostic and predictive indicators in operable breast cancer

Because of its biological heterogeneity and wide spectrum of responsiveness to different treatments, breast cancer is a complex disease of difficult clinical management. Over the past several years, knowledge of the molecular mechanisms regulating normal and aberrant cell growth leading to cancer has been enhanced. These advances have enabled the identification of an increasing number of surrogate biomarkers, which have been correlated with prognosis or used as predictors of response to specific treatments. Axillary nodal status, age, tumor size, pathologic grade, and hormone receptor status are the established prognostic and/or predictive factors for selection of adjuvant treatments. The role of new biomarkers, such as p53, HER2/neu, angiogenesis, and the proliferation index value, is promising; however, the clinical value of their determination must be provided by prospective clinical studies.

Progress toward a peptidomimetic of laminin-derived pentapeptide YIGSR: synthesis of the unique tricyclic core structure

The peptide sequence YIGSR, a segment of the basement membrane matrix glycoprotein laminin, has been identified as a key component in tumor cell invasion. Guided by extensive NMR work and de novo design algorithms, a nonpeptide mimetic of this pentapeptide was identified as a lead candidate for synthesis. The target displays the key amino acid side chains from a novel tricyclic scaffold. The first synthesis of this unique scaffold is completed in 11 steps and 7% overall yield.

Putative role of 67 kDa elastin-laminin receptor in tumor invasion

Cellular regulatory mechanisms normally maintain a delicate balance between cell proliferation, quiescence and death. The imbalance between these functions resulting from molecular intracellular changes is a key factor in tumorigenesis. Tumor cells detaching from the primary tumor possess a propension for invasion and metastasis formation. These tumor cells can attach, migrate, proliferate and grow in host tissue. The surrounding extracellular matrix (ECM) modulates these functions. It is now widely accepted that cell-matrix interactions play an important role in these processes. Most investigators concentrated their attention on the role of integrins in the above processes. There are, however, only scant data on the role of elastin and its receptors in tumor invasion. Nevertheless, experimental evidence indicates that the 67 kDa elastin-laminin receptor (ELR) subunit plays an important role in tumor invasion by mediating essential tumor cell functions leading to metastases. In this review we will concentrate on the putative role of the 67 kDa ELR subunit in tumor invasion.

Potential markers predicting distant metastasis in axillary node-negative breast carcinoma

Prognostic parameters for axillary node-negative (ANN) breast cancer are still rare. Our aim was to establish potential markers that predict distant metastasis in ANN breast carcinoma and permit detection of the patients with high metastasis risk. A case control study was designed that comprised 64 ANN patients who developed distant metastasis during a 5-10 year follow-up period, 64 ANN patients with recurrence-free survival and 64 node-positive (ANP) comparitors. Immunohistochemistry and/or in situ hybridization were used to detect nm23, Cathepsin-D (Cath-D), Epidermal Growth Factor Receptor (EGFR) and Laminin Receptor (LR) in 192 cases. A significantly lower expression of both nm23 mRNA and protein was found in the ANN-group with poor prognosis compared with the ANN-group with good prognosis (p < 0.01). The protein levels of Cath-D, EGFR and LR were significantly higher in the ANN-group with poor prognosis and in the ANP-group compared with the ANN-group with good prognosis (p < 0.01 or p < 0.05), but no differences were found between the poor ANN-group and the ANP-group. Multiple regression analysis showed a close correlation of nm23, Cath-D and EGFR expression with occurrence of distant metastasis of ANN breast carcinoma. All markers except nm23 correlated with conventional histopathologic criteria such as tumor grade, margin and vessel invasion. The results suggest the combined detection of nm23, Cath-D and EGFR as predictive markers of distant metastasis in ANN breast cancer patients. Quantitative analysis together with clinicopathologic factors could contribute to estimate the potential risk of metastasis and select individual therapy regimen.

Midkine binds to 37-kDa laminin binding protein precursor, leading to nuclear transport of the complex

Midkine (MK) is a heparin binding multifunctional protein that promotes cell survival and cell migration. MK was found to bind to 37-kDa laminin binding protein precursor (LBP), a precursor of 67-kDa laminin receptor, with K(d) of 1.1 nM between MK and LBP-glutathione-S-transferase fusion protein. The binding was inhibited by laminin, anti-LBP, amyloid beta-peptide, and heparin; the latter two are known to bind to MK. In CMT-93 mouse rectal carcinoma cells, LBP was mostly located in the cytoplasm as revealed by immunostaining with anti-LBP antibody. That a portion of LBP or 67-kDa laminin receptor was located at the surface of these cells was verified by inhibition of cell attachment to laminin-coated dishes by anti-LBP antibody. When MK was added to culture medium of these cells, a part of LBP migrated to the nucleus. The movement occurred concomitantly with nuclear transport of biotin-labeled MK. These findings suggested that the binding of MK to LBP caused nuclear translocation of the molecular complex.

Genetic imbalances in preleukemic thymuses

To understand the molecular mechanisms involved in preleukemia, the suppression subtractive hybridization method was used in a murine radiation-induced thymic lymphoma model. Seventeen mRNAs overexpressed in preleukemic thymuses were identified: mouse laminin binding protein (p40/37LBP), E25 protein, Rattus norvegicus clone BB.1.4.1, profilin, poly(A) binding protein (PABP), mouse high mobility group protein 1, topoisomerase I, clusterin, proteasome RC1 subunit, rat prostatein C3 and C1 subunits; two ESTs and four unknown genes. The overexpression of PABP, clusterin, profilin, and the p40/37LBP mRNAs was confirmed in preleukemic thymuses and can be related to some cellular events observed during the preleukemic period, i.e., alterations of cell cycle and apoptosis properties. The p40/37LBP and 67-kDa laminin receptor proteins were upregulated during the preleukemic period. The data suggest that additional studies on p40/37LBP and 67-kDa laminin receptor regulation are required to evaluate their potential role in the lymphoma prevention by TNF-alpha and IFN-gamma.

Phage display mapping for peptide 11 sensitive sequences binding to laminin-1

We utilized a 9-mer random phage display library to identify sequences which bind to laminin-1 and elute with heparan sulfate or peptide 11 (CDPGYIGSR). Laminin-1 derivatized plates were used for biopanning. Three consecutive rounds of low pH elutions were carried out, followed by three rounds of specific elutions, each consisting of a heparan sulfate elution followed by a peptide 11 elution. The random sequence inserts were sequenced for phage populations eluted at low pH, by heparan sulfate and by peptide 11. Specifically eluted phage populations exhibited three classes of mimotopes for different regions in the cDNA derived amino acid sequence of the 67 kDa laminin binding protein (LBP). These regions were (1) a palindromic sequence known as peptide G, (2) a predicted helical domain corresponding to LBP residues 205-229, and (3) TEDWS-containing C-terminal repeats. All elution conditions also yielded phage with putative heparin binding sequences. We modeled the LBP(205-229) domain, which is strongly predicted to have a helical secondary structure, and determined that this region likely possesses heparin-binding characteristics located to one side of the helix, while the opposite side appears to contain a hydrophobic patch where peptide 11 could bind. Using ELISA plate assays, we demonstrated that peptide 11 and heparan sulfate individually bound to synthetic LBP(205-229) peptide. We also demonstrated that the QPATEDWSA peptide could inhibit tumor cell adhesion to laminin-1. These data support the proposal that the 67 kDa LBP can bind the beta-1 laminin chain at the peptide 11 region, and suggest that heparan sulfate is a likely alternate ligand for the binding interactions. Our results also confirm previous data suggesting that the most C-terminal region of the LBP, which contains the TEDWS repeats, is involved in cell adhesion to laminin-1, and we specifically implicate the repeat sequence in that activity.

Vascular grading of angiogenesis: prognostic significance in breast cancer

The study aimed to evaluate the prognostic value of angiogenesis by vascular grading of primary breast tumours, and to evaluate the prognostic impact of adding the vascular grade to the Nottingham Prognostic Index (NPI). The investigation included 836 patients. The median follow-up time was 11 years and 4 months. The microvessels were immunohistochemically stained by antibodies against CD34. Angiogenesis was graded semiquantitatively by subjective scoring into three groups according to the expected number of microvessels in the most vascular tumour area. The vascular grading between observers was moderately reproduced (kappa = 0.59). Vascular grade was significantly associated with axillary node involvement, tumour size, malignancy grade, oestrogen receptor status and histological type. In univariate analyses vascular grade significantly predicted recurrence free survival and overall survival for all patients (P < 0.0001), node-negative patients (P < 0.0001) and node-positive patients (P < 0.0001). Cox multivariate regression analysis showed that vascular grading contributed with independent prognostic value in all patients (P < 0.0001). A prognostic index including the vascular grade had clinical impact for 24% of the patients, who had a shift in prognostic group, as compared to NPI, and implied a better prognostic dissemination. We concluded that the angiogenesis determined by vascular grading has independent prognostic value of clinical relevance for patients with breast cancer.

The expression of membrane-associated 67-kDa laminin receptor (67LR) is modulated in vitro by cell-contact inhibition

The interaction of cells with their substratum is an important determinant of cell behaviour, influencing attachment, proliferation, and motility. Such interactions are mediated by cell surface receptors which bind to attachment factors, like the glycoprotein laminin in basement membranes. We have previously shown that expression of the 67-kDa laminin receptor (67LR) is elevated in proliferating retinal microvasculature compared with mature, quiescent vessels. Here, we examined 67LR mRNA and protein expression in primary cultures of retinal microvascular endothelial cells (RMEC) and in the breast cancer cell-line T47D during stages of contact inhibition. In both cell types, the expression levels of 67LR mRNA and membrane-associated 67LR protein were significantly increased during the proliferative phases of monolayer formation. As the cells achieved contact inhibition, 67LR expression was reduced to comparatively low levels. Thus, the differential expression of 67LR between dividing and contact-inhibited cells may indicate a role for this receptor during proliferative processes.

Quantification of microvessel density of breast carcinoma: an assessment of the inter- and intraobserver variation

The density profile of microvessels (MVD) has recently emerged as a prognostically independent morphological marker of various malignancies, including carcinoma of the breast. MVD-scoring may thus afford the pathologist the opportunity to identify subsets of early stage breast cancer patients, which may benefit from adjuvant therapy. Reproducibility studies are, however, mandatory. Fifty sections of invasive breast carcinoma, immunolabelled for Factor VIII-related antigen, were scored independently by two observers for the number of vessel-profiles (v-p) in the following manner: 1) 250 randomly selected high power fields (HPF) were scored by two analysts to evaluate the agreement of the counting per se; and 2) the hot spot(s), i.e. the zones considered the most vessel rich, in the 50 sections were identified and scored twice to evaluate the agreement on selecting hot spots. When the observers evaluated MVD in the very same 250 HPF a median deviation of 2 v-p (10%) was produced. The interobserver disparity was further accentuated when the participants independently had to identify the hot spots with a median deviation of 6 v-p (13%). Intraobserver variation was approximately equal to the interobserver discordance. Divergences were most conspicuous in fields with a complex vasculature. In conclusion the v-p scoring resulted in substantial inter- and intraobserver variation both in selecting hot spots and in performing the scoring per se. Alternative-scoring techniques, including strict stereological principles, should be considered in the morphological evaluation of angiogenesis.

Diminution of 37-kDa laminin binding protein expression reduces tumour formation of murine lung cancer cells

Expression of the 37-kDa laminin binding protein (37LBP/p40), a precursor of the 67-kDa laminin receptor, is well-correlated with the biological aggressiveness of cancer cells. To elucidate the direct role played by 37LBP/p40 in cancer cells, a murine lung cancer cell line T11, the 37LBP/p40 expression of which was remarkably diminished, was established by the introduction of the antisense 37LBP/p40-RNA using a retroviral vector. As a result, the population doubling time of T11 was prolonged (60 h) compared with that of P29, the non-transfected parental cell line (42 h), and TN2, a transfectant with vehicle only (40 h). In-vitro studies also showed that T11 cells adhered to immobilized laminin less firmly than P29 cells did. When 5 x 10(5) cells were subcutaneously inoculated into syngenic mice, the mean survival time of T11-recipients (77.0+/-14.8 days) was also significantly prolonged compared with that for P29 (34.8+/-5.5 days) and TN2 (36.7+/-6.1 days) recipients (P < 0.001). The electron-microscopic view of the tumour tissue revealed that T11 cells were loosely apposed and their intercellular space was markedly widened. Some of the T11 cells sporadically degenerated with the infiltration of lymphocytes and neutrophils. These results suggest that the suppressed expression of 37LBP/p40 reduces the capability of lung cancer cell proliferation in vitro and tumour formation in vivo.

Clinical significance of angiogenic factors in breast cancer

Growth, progression, and metastasis of breast cancer, as well as of most of the other tumors, are angiogenesis-dependent processes. Several pro-angiogenic growth factors and endogenous inhibitors of angiogenesis have been identified and sequenced, and experimental studies suggest that angiogenic activity of a tumor may result from downregulation of inhibitors of angiogenesis or up-regulation of endothelial growth factors. The mechanisms leading to the alteration of the balance between positive and negative modulators of angiogenesis are only partially known. We are at the beginning of research to identify the more active angiogenic factors in human breast cancer, and little information is presently available on their clinical significance. Preliminary results suggest that among the known angiogenic peptides, both vascular endothelial growth factor (VEGF) and platelet-derived endothelial cell growth factor / thymidine phosphorylase (PD-ECGF/TP) have promising prognostic and, perhaps, predictive value. No data are available on the clinical value of co-determination of positive and negative regulators of angiogenesis to look at the angiogenic balance of each single tumor. Only a few studies have assessed the role of endogenous inhibitors of angiogenesis in human breast cancer, with results available only on thrombospondin-1 and -2 (TSP-1, -2). Finally, the determination of some integrins such as alpha6 and alphavbeta3 and of some other endothelial-adhesion molecules seems to be of potential prognostic value. Recognizing which are the more biologically active positive and negative angiogenic factors is the key for the identification not only of new prognostic markers but also of targets for antiangiogenic therapy in human breast cancer.

The 67 kDa laminin receptor as a prognostic factor in human cancer

Different receptors for adhesion molecules, including the monomeric 67 kDa laminin receptor (67LR), are responsible for the interactions between tumor cells and components of the extracellular matrix that play an important role in tumor invasion and metastasis. Clinical data clearly demonstrate the importance of the 67LR in the progression of a wide variety of tumors, including breast, lung, ovary, and prostate carcinomas and lymphomas. Indeed, data on more than 4000 cases of different tumors from different organs studied by immunohistochemistry are all concordant with a role for the 67LR in invasiveness, metastasis, and even tumor growth. This receptor molecule appears to be unusual since the corresponding full-length gene encodes a 37 kDa precursor protein which, after acylation, dimerizes to generate the mature 67 kDa form. The primary function of the membrane receptor is to stabilize the binding of laminin to cell surface integrins, acting as an integrin-accessory molecule, although homology of the gene encoding the receptor precursor with other genes suggests additional functions. Studies conducted to define the structure, expression, and function of this laminin receptor represent a step toward developing therapeutic strategies that target this molecule. In particular, therapeutic approaches that downregulate expression of the receptor on tumor cells might lead to decreased tumor aggressiveness.

The relationship between prognostic and predictive factors in the management of breast cancer

The discovery of new prognostic factors proceeds at a much more rapid pace than our knowledge of how to properly utilize this information in the management of patients with breast cancer, especially those with early breast cancer that has not metastasized to regional lymph nodes. Prognostic factors provide information on how the patient is likely to do regardless of treatment. Predictive factors provide information on whether a patient is likely to benefit from therapy. Most factors identified to date provide prognostic information, but relatively few provide information that is truly helpful in making a therapeutic decision in the management of individual patients. In large part this is because there has been insufficient study of the factor, especially prospective evaluations of the factor. Unfortunately this has resulted in the premature use of this information under the general rubric that patients with a poor prognosis deserve more treatment in spite of the fact that there may be no benefit from that therapy in the poor prognostic group.

Laminin receptor in lymph node negative breast carcinoma

BACKGROUND

Expression of 67 kD laminin binding protein, 67LR, is reported to be associated with invasive and metastatic phenotypes in several types of human malignancies. In mammary carcinomas, however, the biologic role of 67LR has been less clear. The authors explored the potential biologic significance of expression of 67LR in 148 patients with axillary lymph node negative breast carcinoma.

METHODS

Formalin fixed, paraffin embedded histologic sections were immunohistochemically evaluated for 67LR using monoclonal antibody MLuC5. The staining results were correlated with morphologic data as well as with estrogen receptor content and p53 product accumulation.

RESULTS

There were statistically significant correlations between positivity for 67LR and lower histologic grade (P = 0.003), lower nuclear grade (P = 0.002), positivity for estrogen receptor (P = 0.003), and lack of p53 abnormality (P < 0.001). Expression of 67LR had no independent effect on the disease free or overall survival of lymph node negative patients with breast carcinoma. Nevertheless, in the subgroup of 67LR positive patients, positivity for estrogen receptor was associated with significantly longer overall survival (P = 0.008).

CONCLUSIONS

The data from this study suggest that tissue expression of 67LR, as detected by antibody MLuC5, is associated with better differentiated, less aggressive forms of axillary lymph node negative breast carcinoma.

Cell surface and substrate distribution of the 67-kDa laminin-binding protein determined by using a ligand photoaffinity probe

BACKGROUND

Peptide 11, a nine-amino acid sequence from the beta1 chain of laminin-1, has been reported to inhibit tumor cell invasion of basement membranes, and to reduce tumor lung colonization (Iwamoto et al.: Science 238:1132-1134, 1987; Landowski et al.: Clin Exp Metastasis 13:357-372, 1995). The peptide is a ligand for the 32/67-kDa laminin-binding protein (LBP); however, the mechanism by which the 67-kDa LBP promotes invasion is unknown.

METHODS

We have synthesized a highly specific probe for the 67-kDa LBP by adding a biotinylated residue, and replacing the required tyrosine in peptide 11 with the photoactivatable bezophenone crosslinker, 4-benzoyl-L-phenylalanine. This probe was used to follow the distribution of the 67-kDa LBP by gel electrophoresis, fluorescence-activated cell scanning, and confocal microscopy techniques.

RESULTS

A single crosslinked protein, consistent with the high molecular weight form of the LBP, was found on Western blots of membrane detergent extracts from cells treated with the ligand probe. A CHO cell line, manipulated to overexpress the laminin-specific alpha6beta1 integrin, exhibited increased invasiveness, and expressed more cell surface 67-kDa LBP. Membrane-associated 67-kDa LBP was found in the vicinity of focal adhesion plaques and also associated with the matrix substrate. Studies on conditioned medium indicated that the matrix-associated LBP derived from material that was shed from the cells, with more being shed from the more invasive CHO variants.

CONCLUSIONS

These results demonstrate the utility of this novel probe in diverse experimental protocols, and suggest that shedding of the 67-kDa LBP may have a role in promoting tumor cell invasion.

Sidechain and backbone requirements for anti-invasive activity of laminin peptide 11

The structure of laminin peptide 11 (CDPGYIGSR-NH2) contains valuable information for the design of mimetic compounds with anti-invasive and anti-metastatic properties. An alanine scan replacement experiment identified Tyr5, Ile6 and Arg9 residues as contributing significantly to anti-invasive activity. Circular dichroism spectra and NMR alphaH chemical shift values both supported the existence of populations of nonrandom coil solution structures for the analogs tested. A D-Ala4 for Gly4 substituted analog completely lost activity, while an L-Ala4 for Gly4 substituted analog retained half the activity of the parent peptide. These results complement our previous findings with D/L alanine substitutions at the Gly7 position, and together they suggest an 'S'-shaped backbone as likely for the active peptide conformation. NMR-constrained molecular modeling supported a direct involvement of the Tyr5 and Ile6 sidechains in conferring bioactivity, and indicated that the Tyr5 sidechain was buried in the Ala2 for Asp2 substitution. Based on the fact that the peptide 11 sequence derives from the disulfide bonded c-loop of an LE-repeat, we synthesized the cyclic CDPGYIGSRC-NH2 peptide. This analog exhibited good anti-invasive and anti-metastatic activity. NMR modeling experiments suggested that the trans-proline cyclic peptide, would favor an 'S'-shaped backbone conformation. Full retro-inverso analogs of peptide 11 were shown to have anti-invasive activity inferior to that of peptide 11. This weak bioactivity was probed using NMR-constrained molecular dynamics, and revealed potential conformations which limited the ability of the required sidechains to mimic the positions of those in the native peptide conformations.

TNF-alpha and IFN-gamma down-regulate the expression of the metastasis-associated bi-functional 37LRP/p40 gene and protein in transformed keratinocytes

The 37 LRP/p40 molecule is a bi-functional protein in which expression is increased in a large variety of cancers in association with their metastatic phenotype. Here we present the first data concerning the 37 LRP/p40 gene promoter activity and show that it is very active in a cervix carcinoma cell line. Interestingly, despite hallmarks of a housekeeping gene, we show that the 37 LRP/p40 gene promoter can be down-regulated by two potentially anticancerous cytokines, TNF-alpha and IFN-gamma. In addition, the dual fate of the protein, i.e., being intracellularly involved in the cell translation machinery and incorporated into a 67-kDa cell surface protein functioning as a laminin receptor (67LR), is differentially affected by the treatment. Our data suggest multiple regulation levels in the control of the 67LR/37LRP/p40 molecule expression and uncover new clues for the understanding of both the control of expression of this metastasis-associated molecule and the IFN-gamma and TNF-alpha anticancerous action.

Prognostic Factors for Node-negative Breast Cancers: Results of a Study Program by the Japanese Breast Cancer Society

BACKGROUND: Prognostic factors for predicting the recurrence of node-negativebreast cancers have been controversial. The present study was performed to elucidate practically useful prognostic factors using formalin-fixed paraffin sections. METHODS: This was a case-controlled multi-institutional study that composed 40 patients with recurrent node-negative breast cancer and 80 patients with node-negative breast cancer but without recurrence after radical surgery. Tumors weresmaller than 3 cm in diameter and were treated surgically between January 1, 1985 and December 31, 1990. The recurrent and non-recurrent cases were matched with regard to their age, adjuvant chemotherapy and the year in which surgery was performed. Fourteen immunohistochemical factors and 8 histological factors of theprimary tumor were studied on formalin-fixed, paraffin-embedded sections by immunohistochemical and histochemical analyses. RESULTS: According to univariate analysis, factors such as progesterone receptor (PgR), MIB-1, CD44v6, CD44v9 and platelet-derived endothelial cell growth factor (PDECGF) were significantly different between the recurrent and non-recurrent groups (p &ly; 0.1; Wilcoxon-Mann-Whitney analysis). Chi-squared test showed significant differences in MIB-1, cdc2 and stromal plasminogen activator receptor (suPAR). Histologically, mitotic count was also significantly different between the two groups (p < 0.005). Multivariate analysis revealed that positivity for cdc2 (p=0.01), high mitotic count (p=0.04) and negativity for CD44v9 (p=0.02)were independent prognostic factors among variables selected by univariate analysis, and that positivity for MIB-1 (p=0.03) and cdc2 (p =0.01), and negativity for CD44v9 (p =0.03) were independent prognostic factors among the immunohistochemical markers examined. CONCLUSION: Our results indicated that positivity for MIB-1 and cdc2, high mitotic count and negativity for CD44v9 could serve as independent factors for predicting the recurrence of node-negative breast cancer.

Tumoural vascularity as a prognostic factor in cancer patients: the evidence continues to grow

Accurate prognostic indicators would help in identifying patients at high risk for recurrence and death. Recent and previous studies indicate that intratumoural microvessel density (iMVD) of invasive breast carcinoma (a measure of tumour angiogenesis) is associated with aggressive tumour growth; iMVD may thus be a valuable prognostic indicator. Moreover, the bulk of accumulating data indicates that microvessel density in the area of most intense neovascularization in invasive breast carcinoma is an independent, significant and accurate prognostic indicator in predicting poorer survival. Such an indicator would be useful in the selection of high-risk patients with breast carcinoma for systemic adjuvant therapy.

Reduced vascular basement-membrane immunostaining in mucinous tumours of the ovary

Tumour vasculature is heterogeneous, exhibiting a range of vessel densities and the vascular basement membrane (VBM) of tumour blood vessels may be fragmented or absent. Increased microvessel density (MVD) has been reported in mucinous ovarian tumours as compared with other histologic sub-types. We hypothesized that VBM immunostaining differs between regions of the ovarian tumour vasculature and between ovarian tumour types exhibiting different MVD. Serial sections from 56 ovarian tumours were immunostained using antibodies to the VBM components collagen IV, heparan sulphate proteoglycan and laminin, and the endothelial cell marker CD31. Regions of high and average MVD were selected, and the number of vessels positive for each VBM component were counted and expressed as a percentage of the number of CD31-positive vessels. The percentage of VBM-positive vessels did not differ between the high and average MVD regions of borderline or malignant, mucinous and serous tumours. The percentage of VBM-positive vessels in mucinous tumours was less than that observed in malignant and borderline serous tumours and benign tumours (p < 0.02). Possible explanations for these findings are (i) that VBM turnover is similar throughout the vasculature; (ii) that the VBM is present both during angiogenesis and in the newly formed vessels of high MVD regions; or (iii) that an alternative angiogenesis mechanism is utilized in different ovarian tumour types, or even between different regions of the same tumour.

Tumoural vascularity as a prognostic factor in cancer patients: the evidence continues to grow

Accurate prognostic indicators would help in identifying patients at high risk for recurrence and death. Recent and previous studies indicate that intratumoural microvessel density (iMVD) of invasive breast carcinoma (a measure of tumour angiogenesis) is associated with aggressive tumour growth; iMVD may thus be a valuable prognostic indicator. Moreover, the bulk of accumulating data indicates that microvessel density in the area of most intense neovascularization in invasive breast carcinoma is an independent, significant and accurate prognostic indicator in predicting poorer survival. Such an indicator would be useful in the selection of high-risk patients with breast carcinoma for systemic adjuvant therapy.

The role of angiogenesis, laminin and CD44 expression in metastatic behavior of early-stage low-grade invasive breast carcinomas

To investigate the role of tumor angiogenesis, laminin and CD44 expression in metastatic potential of breast cancers, 35 early-stage (T1) and/or low-grade (grade 1) invasive breast carcinomas including 18 metastasizing and 17 non-metastasizing cases were analyzed in the present study. Angiogenesis was assessed by a stereologic method after immunohistochemical staining of vascular endothelium for factor VIII. The quantification of the tumor vascularization was based on the vascular surface density (VSD) and the microvessel number (NVES). The expressions of laminin and CD44 were evaluated by scoring the intensity and distribution of the immunostaining. The assessment of NVES and VSD resulted in a statistically significant difference between the two groups (P < 0.05, independent-samples t-test). In the breast cancers with metastatic spread, NVES was found to be 16.0+/-2.9 mm(-2) whereas it was 8.1+/-0.7 mm(-2) in the metastasizing group. VSD was found to be 59.0+/-12.6 mm(-1) in the metastasizing group and was significantly lower in the non-metastasizing group (33.8+/-2.6 mm[-1]). Immunohistochemistry exhibited strongly positive staining for CD44 in 22% of the breast cancers with metastasis, while 65% of the non-metastasizing cases were found to be negative. The statistical analysis also resulted in a significant difference (P = 0.034, chi2 test). However, the immunohistochemical staining for laminin did not yield any significant difference (P = 0.347, chi2 test). Approximately half of the cases being either metastasizing or non-metastasizing stained weakly positive for laminin. We concluded that angiogenesis and CD44 expression in breast cancers correlated significantly with lymph node or distant metastasis. However, the immunodetection of laminin expression in our study did not help to evaluate its role in the metastatic potential of breast cancers. We concluded that vascular parameters, such as an increase in microvessel number, and CD44 expression might be useful prognostic indicators of metastasis in breast cancer.

Overexpression of the 67 kD laminin receptor correlates with the progression of gastric carcinoma

This retrospective study was designed to investigate the relationship between overexpression of the 67 kD laminin receptor (67LR) using immunohistochemistry, and several clinicopathological parameters including overall survival in human gastric adenocarcinoma. We stained paraffin-embedded sections of 93 resected primary gastric adenocarcinomas using a polyclonal antibody specific for the 67LR as well as monoclonal antibodies for p53 protein, epidermal growth factor receptor, proliferating cell nuclear antigen, carcinoembryonic antigen and chromagranin. The results showed statistically significant correlations between overexpression of the 67LR and types of early or advanced gastric carcinoma (p < 0.001), depth of invasion (p < 0.001), WHO histopathologic classification (p < 0.001), stage (p = 0.001), expression of p53 protein (p = 0.019), expression of epidermal growth factor receptor (p < 0.001) and proliferating cell nuclear antigen labeling index (p = 0.002). A lower proportion of signet ring cells revealed a higher percentage of overexpression of 67LR in both early (p < 0.002) and advanced (p < 0.001) gastric carcinomas. Intestinal type adenocarcinoma (according to Lauren's classification) revealed a higher percentage of overexpression of the 67LR than the diffuse type in both early (p = 0.057) and advanced (p < 0.001) gastric carcinomas. The correlations between overexpression of the 67LR and lymph node metastasis were statistically significant (p < 0.07). Although the overexpression of the 67LR tended to correlate with lower survival rates, the correlation was not statistically significant due to the limited sample size. Our data revealed that overexpression of the 67LR is correlated with the progression of gastric carcinoma. The expression of the 67LR may be important as one of the steps which determines invasiveness during the progression of cancer.