Prognostic significance of laminin production in relation with its receptor expression in human breast carcinomas

An adiponectin paralog protein, CTRP6 decreased the proliferation and invasion activity of oral squamous cell carcinoma cells: possible interaction with laminin receptor pathway

C1q/tumor necrosis factor-related protein-6 (CTRP6), also known as CTRP6 is identified adiponectin paralog. Although recent studies have revealed that adiponectin has an inhibitory role in carcinogenesis, the role of CTRP6 in carcinogenesis remains unclear. In this study, we found that eukaryotic recombinant CTRP6 protein bound to the cell surface membrane of cultured oral squamous cell carcinoma cells by immunofluorescence staining. Screening of CTRP6 binding protein in expression library followed by co-immunoprecipitation assay revealed that CTRP6 bound to the precursor of laminin receptor. CTRP6 disturbed the binding of laminin to the laminin receptor. Interestingly, the eukaryotic recombinant CTRP6 protein significantly suppressed the proliferation and Matrigel invasion activity of oral squamous cell carcinoma SAS cells in a dose-dependent manner. Moreover, administration of CTRP6 significantly attenuated the growth of SAS cells in xenoplant mice model. Laminin and laminin receptor are known to be overexpressed and promote the tumor growth in OSCC. Combined together, the present findings suggest that CTRP6 could repress progression of oral squamous cell carcinoma cells, putatively through disrupting the laminin-laminin receptor axis.

Systematic analysis of tumour cell-extracellular matrix adhesion identifies independent prognostic factors in breast cancer

Tumour cell-extracellular matrix (ECM) interactions are fundamental for discrete steps in breast cancer progression. In particular, cancer cell adhesion to ECM proteins present in the microenvironment is critical for accelerating tumour growth and facilitating metastatic spread. To assess the utility of tumour cell-ECM adhesion as a means for discovering prognostic factors in breast cancer survival, here we perform a systematic phenotypic screen and characterise the adhesion properties of a panel of human HER2 amplified breast cancer cell lines across six ECM proteins commonly deregulated in breast cancer. We determine a gene expression signature that defines a subset of cell lines displaying impaired adhesion to laminin. Cells with impaired laminin adhesion showed an enrichment in genes associated with cell motility and molecular pathways linked to cytokine signalling and inflammation. Evaluation of this gene set in the Molecular Taxonomy of Breast Cancer International Consortium (METABRIC) cohort of 1,964 patients identifies the F12 and STC2 genes as independent prognostic factors for overall survival in breast cancer. Our study demonstrates the potential of in vitro cell adhesion screens as a novel approach for identifying prognostic factors for disease outcome.

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.

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.

Vimentin and laminin expression is associated with basal-like phenotype in both sporadic and BRCA1-associated breast carcinomas

AIMS

To determine whether basal-like phenotype and vimentin and/or laminin are related in both sporadic/familial (BRCA1 or BRCA2 mutated) tumours.

METHODS

230 non-familial and 28 hereditary node-negative invasive breast carcinomas were immunohistochemically analysed for oestrogen receptors (ER), progesterone receptors (PR), cytokeratin 5/6 (CK5/6), epidermal growth factor receptors (EGFR), Ki67, p53, vimentin and laminin, using tissue microarrays. Tumours were considered to have basal-like phenotype if they were ER negative and HER2 negative, but positive for CK5/6 and/or EGFR.

RESULTS

In sporadic tumours, vimentin expression was found in 77.8% cases with basal-like phenotype and 15.5% of non-basal cases (p<0.001). In familial cases, vimentin was expressed in 83.3% basal-like cancers and 16.7% of non-basal tumours (p<0.001). Vimentin expression was more frequent in BRCA1 than BRCA2 mutation carriers. Vimentin expressing tumours were associated with poor prognosis (p = 0.012) among patients not receiving adjuvant chemotherapy and showed a trend for local recurrence or visceral but not bone metastasis (p = 0.021). Laminin expression was also related to basal-like phenotype in both sporadic/familial cases (p<0.001 and p = 0.007, respectively), but neither with prognosis nor recurrence pattern in sporadic cancers.

CONCLUSIONS

Vimentin and laminin expression is associated with basal-like phenotype in breast cancer. Expression of vimentin and laminin is characteristic of BRCA1 associated tumours. Since vimentin and laminin staining is widely used by pathologists for diagnostic purposes, thus demonstrating the robustness of their specific antibodies, the immunohistochemical evaluation of these two molecules could be used in identification of basal-like breast tumours in both sporadic/familial cases.

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.

New insights into the role of extracellular matrix during tumor onset and progression

Recently, a view of the tumor as a functional tissue interconnected with the microenvironment has recently been described. For many years, the stroma has been studied in the context of the malignant lesion, and only rarely has its role been considered before carcinogenic lesions appear. Recent studies have provided evidence that stromal cells and their products can cause the transformation of adjacent cells through transient signaling that leads to the disruption of homeostatic regulation, including control of tissue architecture, adhesion, cell death, and proliferation. It is now well established that tumor progression requires a continually evolving network of interactions between neoplastic cells and extracellular matrix. A relevant step of this process is the remodeling of microenvironment which surrounds tumors leading to the release of ECM-associated growth factors which can then stimulate tumor and/or endothelial cells. Finally, tumor cells reorganizing the extracellular matrix to facilitate communications and escape the homeostatic control exerted by the microenvironment modify response to cytotoxic treatments.

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.

Detection of laminin in serum and ascites from patients with epithelial ovarian tumor

The change in serum laminin (LN) level and its clinical significance in epithelial ovarian tumor were investigated. The LN levels in serum and ascites samples from 69 patients with epithelial ovarian tumor and 42 cases as control group before and after operation were analyzed by radioimmunoassay. The results showed that the serum LN levels in the patients with malignant tumors (157.85 +/- 14.37 ng/ml) were significantly higher than that in the control group (125.14 +/- 7.03 ng/ml) and in the patients with benign tumors (128.36 +/- 8.75 ng/ml) (both P < 0.01) before operation. The serum LN levels in the malignant group were decreased significantly after operation as compared with those before operation (P < 0.05). The serum LN levels in low-differentiated tumors was higher than those in moderate-differentiated tumors and high-differentiated tumors (P < 0.05). The LN levels in ascites (172.94 +/- 15.26 ng/ml) was significantly higher than in serum (161.34 +/- 6.59 ng/ml) (P < 0.05) in malignant tumors. The serum LN levels in the patients with lymph node metastasis (165.41 +/- 19.91 ng/ml) was obviously higher than those without lymph node metastasis (152.35 +/- 10.34 ng/ml) (P < 0.05). It was concluded that LN levels in serum and acistis were remarkably increased in malignant epithelial ovarian tumors, suggesting that LN might be one of important diameters reflecting tumor biological characteristics.

Characterization of morphological and cytoskeletal changes in MCF10A breast epithelial cells plated on laminin-5: comparison with breast cancer cell line MCF7

The extracellular matrix regulates functional and morphological differentiation of mammary epithelial cells both in vivo and in culture. The MCF10A human breast epithelial cell line is ideal for studying these processes because it retains many characteristics of normal breast epithelium. We describe a distinct set of morphological changes occurring in MCF10A cells plated on laminin-5, a component of the breast gland basement membrane extracellular matrix. MCF10A cells adhere and spread on laminin-5 about five times more rapidly than on fibronectin or uncoated surfaces. Within 10 minutes from plating on laminin-5, they send out microfilament-rich filopodia and by 30 minutes acquire a cobblestone appearance with microfilaments distributed around the cell periphery. At 90 minutes, with or without serum, > 75% of the MCF10A cells plated on laminin-5 remain in this stationary cobblestone phenotype, while the remainder takes on a motile appearance. Even after 18 hours, when the culture is likely entering an exponential growth phase, the majority of cells maintain a stationary cobblestone appearance, though motile cells have proportionally increased. In contrast, the fully transformed, malignant human breast epithelial cells, MCF7, never acquire a stationary cobblestone appearance, do not organize peripheral microfilaments, and throughout the early time points up to 120 min appear to be constantly motile on laminin-5. We propose that changes in morphology and microfilament organization in response to laminin-5 may represent a benchmark for distinguishing normal vs. malignant behavior of epithelial cells derived from the mammary gland. This may lead to better model systems for studying the interactions between breast epithelium and the basement membrane extracellular matrix, which appear to be deregulated in processes like carcinogenesis and metastasis.

Human Breast Carcinoma Patients Develop Clonable Oncofetal Antigen-Specific Effector and Regulatory T Lymphocytes

Oncofetal Ag (OFA) is a 44-kDa glycoprotein expressed during early to mid-gestation fetal development and re-expressed as a surface Ag by tumor cells soon after transformation. The Ag is detectable on all types of human and rodent tumors tested, but is undetectable on normal cells. In experimental animals it is autoimmunogenic and induces potentially protective T cell responses both after experimental immunization and during tumor development subsequent to carcinogenic insult. To determine whether this tumor-associated Ag is also immunogenic for human T lymphocytes, breast carcinoma patients’ peripheral blood mononuclear leucocytes were stimulated in vitro with autologous tumor cells in the presence of IL-2, γ-IFN, and IL-6 for 2 wk. The tumor-reactive cells were then restimulated and cloned by limiting dilution, and the clones were analyzed. We established 24, 19, 11, and 16 tumor-reactive clones from the four respective patients. Of those, 4, 6, 4, and 7, respectively, proliferated specifically to purified OFA. Both CD4 and CD8 OFA-specific clones were established, which responded equally well to purified OFA or 32- to 44-kDa immature laminin receptor protein. All were CD3+, TCR-αβ+. All CD4 clones secreted γ-IFN, but neither secreted IL-4 nor IL-10. Both IFN-γ-secreting cytotoxic CD8 clones and IL-10-secreting inhibitory CD8 clones were established. Thus, during human cancer development, the same types of OFA-specific effector and regulatory T cells are induced as during murine T lymphomagenesis.

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.

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.

Expression of extracellular matrix proteins in cervical squamous cell carcinoma--a clinicopathological study

AIM

To evaluate the intracellular and peritumoral expression of matrix proteins in squamous cell carcinoma of the uterine cervix using immunohistochemistry.

METHODS

71 squamous cell carcinomas and 10 controls were stained for laminin, fibronectin, and collagen IV. Cytoplasmic staining in tumour cells and peritumoral deposition of matrix proteins were evaluated. The association between staining results and patient age, tumour stage, histological grade, and survival was studied.

RESULTS

Positive cytoplasmic staining for laminin, fibronectin, and collagen IV was observed in 17 (23.9%), 27 (38%), and 10 (14.1%) cases, respectively. Staining for laminin was most pronounced in the invasive front of tumour islands, while for fibronectin and collagen IV it appeared to be diffuse. Peritumoral staining for laminin and collagen IV was detected in 12 cases (16.9%). Early stage (Ia1-Ia2) tumours were uniformly negative for all three proteins. Cytoplasmic staining for laminin correlated with positive staining for fibronectin and collagen IV, and with the presence of a peritumoral deposition of collagen IV and laminin. There was no correlation with any of the three markers between staining results and patient age, stage, grade, or survival.

CONCLUSIONS

Expression of extracellular matrix proteins in some cervical squamous cell carcinomas might reflect the enhanced ability of these tumours to modify the peritumoral stroma. This ability seems to be absent in early stage tumours. The correlation between intracytoplasmic and peritumoral expression of matrix proteins supports the evidence of their synthesis by tumour cells. However, this property did not correlate with disease outcome in this study.

Possibilities of a viral etiology for human breast cancer. A review

Previous studies related mouse mammary tumor virus (MMTV) to human breast cancer. However, the presence of human endogenous retroviruses (HERs) confounded these results. We selected a 660-bp sequence of the MMTV env gene with low homology to HER (or any other known gene) and searched for a sequence homologous to it, using the polymerase chain reaction (PCR). The 660-bp sequence was detected in 131 (39%) of 335 unselected breast cancers, in 2 (6.9%) of 29 fibroadenomas, and in 2 (1.65%) of 121 normal breast specimens. The sequence was not present in normal tissues, or in other human cancers or cell lines. Cloning and sequencing of the 660-bp sequence revealed that it is 95-98% homologous to MMTV env gene, but not the known HERs or other viral or human gene. Southern blot hybridization using labeled cloned sequences demonstrated that the 660-bp sequence was present in very low copy number as a 6-8 kb EcoRI fragment only in breast cancer samples and in some of the human breast cancer cell lines that were positive by PCR. Preliminary experiments using reverse transcriptase (RT)-PCR indicated that expression of the 660-bp sequence can be detected in 65% of the positive tumors. We were also able to identify in breast cancer DNA a segment of 1.6 kb comprising LTR and env gene sequences, which are homologous to MMTV, but not to the HERs. The origin of the MMTV-like sequences in tumor DNA could be the result of integrated MMTV-like sequences derived from a human mammary virus.

Peptide G, containing the binding site of the 67-kDa laminin receptor, increases and stabilizes laminin binding to cancer cells

We investigated the effect of peptide G, a synthetic peptide derived from the sequence of the 37-kDa laminin receptor precursor, on the interaction of laminin in two tumor cell lines one of which produces laminin and one of which does not. Addition of peptide G to the culture medium induced a significant increase in the amount of endogenous laminin detectable on the cell membrane of both cell lines. Moreover, pretreatment of exogenous laminin with peptide G dramatically increased laminin binding on both cell lines. Kinetics analysis of membrane-bound labeled laminin revealed a 3-fold decrease in the kd of peptide G-treated laminin compared with untreated or unrelated or scrambled peptide-treated laminin. Moreover, the affinity constant of peptide G-treated laminin increased 2-fold, with a doubling of the number of laminin binding sites, as determined by Scatchard analysis. Expression of the VLA6 integrin receptor on the cell membrane increased after incubation with peptide G-treated laminin. However, the lower binding inhibition of peptide G-treated laminin after anti-VLA6 antibody or cation chelation treatment indicates that membrane molecules in addition to integrin receptors are involved in the recognition of peptide G-modified laminin. These "new" laminin-binding proteins also mediated cell adhesion to laminin, the first step in tumor invasion. Together, the data suggest that peptide G increases and stabilizes laminin binding on tumor cells, involving surface receptors that normally do not take part in this interaction. This might explain the abundant clinical and experimental data suggesting a key role for the 67-kDa laminin receptor in the interaction between cancer cells and the basement membrane glycoprotein laminin during tumor invasion and metastasis.

Laminin activates the p185HER2 oncoprotein and mediates growth inhibition of breast carcinoma cells

The interaction between laminin and the oncoprotein encoded by the c-erbB-2 oncogene was studied in vitro and in vivo in human breast carcinomas. In vitro analysis of breast carcinoma cell lines overexpressing p185HER2 revealed that laminin, but not fibronectin, induced tyrosine phosphorylation and down-modulation of oncoprotein membrane expression. Laminin also specifically inhibited growth of p185HER2-positive cell lines. No direct binding between the recombinant extracellular domain of p185HER2 and laminin was found. Induction of oncoprotein down-modulation by anti-integrin antibodies and coprecipitation of the oncoprotein with the beta 4 integrin subunit indicate that the interaction between p185HER2 and laminin occurs through integrin molecules. The relevance of this in vitro observation was verified in vivo by analysing the prognostic value of p185HER2 overexpression as a function of laminin production on archival paraffin-embedded sections of 887 primary breast tumours. The results revealed an association between p185HER2 overexpression and unfavourable prognosis in tumours negative for laminin production, whereas in laminin-producing tumours, the oncoprotein overexpression was not associated with tumour aggressiveness.