An immunohistochemical examination of the expression of E-cadherin, alpha- and beta/gamma-catenins, and alpha2- and beta1-integrins in invasive breast cancer

Amygdalin Exerts Antitumor Activity in Taxane-Resistant Prostate Cancer Cells

Despite recent advances in the treatment of metastatic prostate cancer (PCa), resistance development after taxane treatments is inevitable, necessitating effective options to combat drug resistance. Previous studies indicated antitumoral properties of the natural compound amygdalin. However, whether amygdalin acts on drug-resistant tumor cells remains questionable. An in vitro study was performed to investigate the influence of amygdalin (10 mg/mL) on the growth of a panel of therapy-naïve and docetaxel- or cabazitaxel-resistant PCa cell lines (PC3, DU145, and LNCaP cells). Tumor growth, proliferation, clonal growth, and cell cycle progression were investigated. The cell cycle regulating proteins (phospho)cdk1, (phospho)cdk2, cyclin A, cyclin B, p21, and p27 and the mammalian target of rapamycin (mTOR) pathway proteins (phospho)Akt, (phospho)Raptor, and (phospho)Rictor as well as integrin β1 and the cytoskeletal proteins vimentin, ezrin, talin, and cytokeratin 8/18 were assessed. Furthermore, chemotactic activity and adhesion to extracellular matrix components were analyzed. Amygdalin dose-dependently inhibited tumor growth and reduced tumor clones in all (parental and resistant) PCa cell lines, accompanied by a G0/G1 phase accumulation. Cell cycle regulating proteins were significantly altered by amygdalin. A moderate influence of amygdalin on tumor cell adhesion and chemotaxis was observed as well, paralleled by modifications of cytoskeletal proteins and the integrin β1 expression level. Amygdalin may, therefore, block tumor growth and disseminative characteristics of taxane-resistant PCa cells. Further studies are warranted to determine amygdalin’s value as an antitumor drug.

Functional Redundancy between β1 and β3 Integrin in Activating the IR/Akt/mTORC1 Signaling Axis to Promote ErbB2-Driven Breast Cancer

Integrin receptors coordinate cell adhesion to the extracellular matrix (ECM) to facilitate many cellular processes during malignant transformation. Despite their pro-tumorigenic roles, therapies targeting integrins remain limited. Here, we provide genetic evidence supporting a functional redundancy between β1 and β3 integrin during breast cancer progression. Although ablation of β1 or β3 integrin alone has limited effects on ErbB2-driven mammary tumorigenesis, deletion of both receptors resulted in a significant delay in tumor onset with a corresponding impairment in lung metastasis. Mechanistically, stiff ECM cooperates with integrin receptors to recruit insulin receptors (IRs) to focal adhesion through the formation of integrin/IR complexes, thereby preventing their lysosomal degradation. β1/β3 integrin-deficient tumors that eventually emerged exhibit impaired Akt/mTORC1 activity. Murine and human breast cancers exhibiting enhanced integrin-dependent activity also display elevated IR/Akt/mTORC1 signaling activity. Together, these observations argue that integrin/IR crosstalk transduces mechanical cues from the tumor microenvironment to promote ErbB2-dependent breast cancer progression.

Beta 1 integrin signaling mediates pancreatic ductal adenocarcinoma resistance to MEK inhibition

Pancreatic cancer, one of the deadliest human malignancies, has a dismal 5-year survival rate of 9%. KRAS is the most commonly mutated gene in pancreatic cancer, but clinical agents that directly target mutant KRAS are not available. Several effector pathways are activated downstream of oncogenic Kras, including MAPK signaling. MAPK signaling can be inhibited by targeting MEK1/2; unfortunately, this approach has been largely ineffective in pancreatic cancer. Here, we set out to identify mechanisms of MEK inhibitor resistance in pancreatic cancer. We optimized the culture of pancreatic tumor 3D clusters that utilized Matrigel as a basement membrane mimetic. Pancreatic tumor 3D clusters recapitulated mutant KRAS dependency and recalcitrance to MEK inhibition. Treatment of the clusters with trametinib, a MEK inhibitor, had only a modest effect on these cultures. We observed that cells adjacent to the basement membrane mimetic Matrigel survived MEK inhibition, while the cells in the interior layers underwent apoptosis. Our findings suggested that basement membrane attachment provided survival signals. We thus targeted integrin β1, a mediator of extracellular matrix contact, and found that combined MEK and integrin β1 inhibition bypassed trametinib resistance. Our data support exploring integrin signaling inhibition as a component of combination therapy in pancreatic cancer.

In vivo modeling of the EGFR family in breast cancer progression and therapeutic approaches

Modeling breast cancer through the generation of genetically engineered mouse models (GEMMs) has become the gold standard in the study of human breast cancer. Notably, the in vivo modeling of the epidermal growth factor receptor (EGFR) family has been key to the development of therapeutics and has helped better understand the signaling pathways involved in cancer initiation, progression and metastasis. The HER2/ErbB2 receptor is a member of the EGFR family and 20% of breast cancers are found to belong in the HER2-positive histological subtype. Historical and more recent advances in the field have shaped our understanding of HER2-positive breast cancer signaling and therapeutic approaches.

Breast Cancer Tumor Stroma: Cellular Components, Phenotypic Heterogeneity, Intercellular Communication, Prognostic Implications and Therapeutic Opportunities

Although the mechanisms underlying the genesis and progression of breast cancer are better understood than ever, it is still the most frequent malignant tumor in women and one of the leading causes of cancer death. Therefore, we need to establish new approaches that lead us to better understand the prognosis of this heterogeneous systemic disease and to propose new therapeutic strategies. Cancer is not only a malignant transformation of the epithelial cells merely based on their autonomous or acquired proliferative capacity. Today, data support the concept of cancer as an ecosystem based on a cellular sociology, with diverse components and complex interactions between them. Among the different cell types that make up the stroma, which have a relevant role in the dynamics of tumor/stromal cell interactions, the main ones are cancer associated fibroblasts, endothelial cells, immune cells and mesenchymal stromal cells. Several factors expressed by the stroma of breast carcinomas are associated with the development of metastasis, such as matrix metalloproteases, their tissular inhibitors or some of their regulators like integrins, cytokines or toll-like receptors. Based on the expression of these factors, two types of breast cancer stroma can be proposed with significantly different influence on the prognosis of patients. In addition, there is evidence about the existence of bi-directional signals between cancer cells and tumor stroma cells with prognostic implications, suggesting new therapeutic strategies in breast cancer.

Re-Evaluating E-Cadherin and β-Catenin: A Pan-Cancer Proteomic Approach with an Emphasis on Breast Cancer

E-cadherin is conventionally considered to be a good prognostic marker in cancer. The loss of E-cadherin is one of the key hallmarks of epithelial-to-mesenchymal transition, a biological process that promotes cancer cell invasiveness and metastasis. Recent evidence has cast doubt on the importance of epithelial-to-mesenchymal transition in metastasis. The availability of protein-level data in the Cancer Genome Atlas allows for the quantitative analysis of protein and prognosis. The prognostic values of E-cadherin and β-catenin were revisited across 19 cancer types, and high E-cadherin was found to correlate with good prognosis in most cancers. Conversely, higher E-cadherin and β-catenin correlated with shorter survival in invasive breast carcinoma. Stratifying breast cancers by histologic subtype revealed that the poor prognosis of E-cadherin and β-catenin proteins was characteristic of infiltrating ductal, but not lobular, carcinomas. To further corroborate the protein findings and examine cellular localization, immunohistochemistry was used for E-cadherin and β-catenin in 163 breast patient samples from the Iowa cohort. Most previous studies showing that reduced or absent E-cadherin and β-catenin was inversely associated with tumor stages in ductal carcinomas were confirmed. Taken together, these results lead us to question the prognostic values of E-cadherin and β-catenin in ductal carcinomas and indicate a complicated role of E-cadherin and β-catenin in breast cancer progression.

Prognostic value of increased integrin-beta 1 expression in solid cancers: a meta-analysis

Integrin-beta 1 (ITGB1) is aberrantly overexpressed or downregulated in solid cancers; however, its prognostic value remains controversial. Therefore, we conducted a meta-analysis to explore whether ITGB1 expression is correlated with overall survival (OS) and the clinicopathological characteristics of patients with solid cancers. We systematically searched the PubMed, Embase, and Web of Science databases for eligible studies published up to June 1, 2017. In total, 22 studies involving 3,666 patients were included. A sensitivity analysis was performed to assess the validity and reliability of the pooled OS. Among the 22 studies, 7 focused on lung cancer, 3 focused on colorectal cancer, 6 focused on breast cancer, 3 involved melanoma, and 3 involved pancreatic cancer. The pooled results showed that high ITGB1 expression was significantly associated with worse OS in lung cancer (pooled hazard ratio [HR]=1.78, 95% CI: 1.19–2.65, p<0.05) and breast cancer (pooled HR=1.88, 95% CI: 1.46–2.42, p<0.01). In addition, a significant association was observed between high ITGB1 expression and disease-free survival in breast cancer (pooled HR=1.63, 95% CI: 1.17–2.25, p<0.001) and pancreatic cancer (pooled HR=2.49, 95% CI: 1.35–4.61, p<0.001). However, high ITGB1 expression was not related to OS in colorectal cancer, pancreatic cancer, or melanoma. The pooled HRs used to evaluate the prognostic value of increased ITGB1 expression in lung cancer, breast cancer, and pancreatic cancer were not significantly altered, which indicates that the pooled results were robust. The results of this study indicate that the prognostic value of decreased ITGB1 expression varies among solid cancers.

β1 and β3 integrins in breast, prostate and pancreatic cancer: A novel implication

Integrins are transmembrane glycoproteins that consist of an α and a β subunit. Specific integrin heterodimers preferentially bind to distinct extracellular matrix (ECM) proteins to affect the characteristics of cells or the components of the ECM. Among the different integrins, β1 and β3 integrins serve essential roles in the progression of different cancer-associated processes, including the initiation, proliferation, survival, migration and invasion. Furthermore, previous studies have revealed a ratio between these two integrins in cancer cells, which also demonstrated that the functions of these two integrins are paradoxical. This indicated that the proliferation and metastasis of cancer cells are not always parallel and may be considered independently maintained. Additionally, the present review may assist in understanding certain aspects of cancer, and in making clinical decisions in a novel and more comprehensive manner.

Immunocytochemical stem cell markers can predict clinical stage of breast cancer

We present a computational-statistical algorithm that, from data on the staining degree of immunocytochemical markers: i) evaluates the ability of the considered immuno-panel in predicting the breast cancer stage; ii) makes the accurate identification of breast cancer stage possible; iii) provides the best stage prognosis compatible with the considered sample; and iv) does so through the use of the minimum number of markers minimizing time and resource costs. After running the algorithm on two data sets [triple-negative breast cancer, (TNBC), and estrogen receptor-negative breast cancer, (ERNBC)], we conclude that EpCAM and β1 integrin are enough to accurately predict TNBC stage, being ALDH1, CD24, CD61, and CK5 the necessary markers to exactly predict ERNBC stage.

FOXM1 transcriptionally regulates expression of integrin β1 in triple-negative breast cancer

PURPOSE

Triple-negative breast cancer (TNBC) is an aggressive type of breast cancer and associated with early metastasis, drug resistance, and poor patient survival. Fork head box M1 (FOXM1) is considered as an emerging molecular target due to its oncogenic role and high overexpression profile in 85% in TNBC. However, molecular mechanisms by which FOXM1 transcription factor mediate its oncogenic effects are not fully understood. Integrin β1 is often upregulated in invasive breast cancers and associated with poor clinical outcome and shorter overall patient survival in TNBC. However, the mechanisms regulating integrin β1 (ITGB1) gene expression have not been well elucidated.

METHODS

Normal breast epithelium (MCF10A) and TNBC cells (i.e., MDA-MB-231, BT-20 MDA-MB436) were used for the study. Small interfering RNA (siRNA)-based knockdown was used to inhibit Integrin β1 gene (mRNA) and protein expressions, which are detected by RT-PCR and Western blot, respectively. Chromatin immunoprecipitation (ChiP) and gene reporter (Luciferase) assays were used to demonstrate that FOXM1 transcription factor binds to the promoter of Integrin β1 gene and drives its expression.

RESULTS

We demonstrated that FOXM1 directly binds to the promoter of integrin β1 gene and transcriptionally regulates its expression and activity of focal adhesion kinase (FAK) in TNBC cells.

CONCLUSION

Our study suggests that FOXM1 transcription factor regulates Integrin β1 gene expression and that FOXM1/ Integrin-β1/FAK axis may play an important role in the progression of TNBC.

E3 Ubiquitin Ligase UBR5 Drives the Growth and Metastasis of Triple-Negative Breast Cancer

Patients with triple-negative breast cancers (TNBC) are at high risk for recurrence and metastasis at an early time despite standard treatment, underscoring the need for novel therapeutic modalities. Here, we report for the first time a distinctive and profound role of the E3 ubiquitin ligase UBR5 in the growth and metastasis of TNBC. An analysis of primary TNBC specimen by whole-exon sequencing revealed strong gene amplifications of UBR5 associated with the disease. UBR5 overexpression in TNBC tissues was confirmed at mRNA and protein levels. CRISPR/Cas9-mediated deletion of ubr5 in an experimental murine mammary carcinoma model of TNBC dramatically abrogated tumor growth and metastasis in vivo, which could be reversed completely via reconstitution with wild-type UBR5 but not a catalytically inactive mutant. Loss of UBR5 caused an impairment in angiogenesis within the tumor, associated with increased apoptosis, necrosis, and growth arrest. Absence of UBR5 in the tumor triggered aberrant epithelial-to-mesenchymal transition, principally via abrogated expression of E-cadherin, which resulted in severely reduced tumor metastasis to secondary organs. Use of NOD/SCID mice revealed that tumor-derived UBR5 facilitated tumor growth in a manner completely dependent upon immune cells in the microenvironment, whereas it promoted metastasis in a tumor cell-autonomous fashion. Our findings unveil UBR5 as a novel and critical regulator of tumor growth, metastasis, and immune response and highlight the potential for UBR5 as an effective therapeutic target for the treatment of highly aggressive breast and ovarian cancers that fail conventional therapy. Cancer Res; 77(8); 2090-101. ©2017 AACR.

Prognostic Value of E-Cadherin and β-Catenin in Triple-Negative Breast Cancer

OBJECTIVES

To analyze the expression of E-cadherin and β-catenin in triple-negative breast cancer (TNBC) to assess their prognostic significance.

METHODS

The expression of E-cadherin and β-catenin was examined semiquantitatively and correlated with other pathologic factors and survival outcomes.

RESULTS

Of 72 consecutive TNBCs, 56% showed reduced membranous expression of E-cadherin or β-catenin, with a strong correlation to each other. Of the clinicopathologic factors analyzed, tumor size and nodal status were significantly associated with overall survival and disease-specific survival, while the latter remained an independent factor by multivariate analysis. Reduced E-cadherin and β-catenin were both significantly associated with a poor overall survival and disease-specific survival by univariate and multivariate analyses.

CONCLUSIONS

E-cadherin and β-catenin expression provides discriminative prognostic power independent of conventional pathologic factors, thus further reinforcing the important role of cell adhesion molecules in the process of tumor metastasis, especially in TNBC.

E-cadherin re-expression shows in vivo evidence for mesenchymal to epithelial transition in clonal metastatic breast tumor cells

Substantial experimental evidence has shown that dedifferentiation from an epithelial state to a mesenchymal-like state (EMT) drives tumor cell metastasis. This transition facilitates tumor cells to acquire motility and invasive features. Intriguingly, tumor cells at the metastatic site are primarily epithelial, and it is believed that they differentiate back to an epithelial state by a process called mesenchymal to epithelial transition (MET). However, there is little in vivo evidence to support the MET process. To investigate EMT and MET in vivo, we generated two epithelial (E) and two mesenchymal (M) primary clonal cell lines from a spontaneous mouse mammary tumor (Tg MMTV/neu). These cells were labeled with reporters (GFP and luciferase), and tracked in vivo during primary tumor growth and subsequent secondary metastasis. Once E cells were implanted into the mammary fat pad, E-cadherin expression progressively decreased and continued to decrease as the primary tumor enlarged over time. A greater percentage of E tumor cells expressed E-cadherin at the secondary metastatic site as compared to the corresponding primary tumor site. Collectively, these data provide direct in vivo evidence that epithelial tumor cells have metastatic potential, undergo EMT at the primary tumor site, and MET at the metastatic site.

Lack of CD151/integrin α3β1 complex is predictive of poor outcome in node-negative lobular breast carcinoma: opposing roles of CD151 in invasive lobular and ductal breast cancers

Background:

The proposed involvement of CD151 in breast cancer (BCa) progression is based on findings from studies in invasive ductal carcinoma (IDC). The IDC and invasive lobular carcinoma (ILC) represent distinct disease entities. Here we evaluated clinical significance of CD151 alone and in association with integrin α3β1 in patients with ILC in context of the data of our recent IDC study.

Methods:

Expression of CD151 and/or integrin α3β1 was evaluated in ILC samples (N=117) using immunohistochemistry. The findings were analysed in relation to our results from an IDC cohort (N=182) demonstrating a prognostic value of an expression of CD151/integrin α3β1 complex in patients with HER2-negative tumours.

Results:

Unlike in the IDCs, neither CD151 nor CD151/α3β1 complex showed any correlation with any of the ILC characteristics. Lack of both CD151 and α3β1 was significantly correlated with poor survival (P=0.034) in lymph node-negative ILC N(−) cases. The CD151⁻/α3β1⁻ patients had 3.12-fold higher risk of death from BCa in comparison with the rest of the ILC N(−) patients.

Conclusions:

Biological role of CD151/α3β1 varies between ILC and IDC. Assessment of CD151/α3β1 might help to identify ILC N(−) patients with increased risk of distant metastases.

The expression of β-catenin in different subtypes of breast cancer and its clinical significance

The Wnt/β-catenin signaling pathway is implicated in mammary oncogenesis. Reports of β-catenin expression and its association with outcome in breast cancer are controversial. This study was performed to address the distribution of β-catenin expression in invasive breast cancer and the correlation between β-catenin expression and survival of breast cancer patients, and to determine whether β-catenin was specifically activated in any molecular subtypes. Immunohistochemistry was performed on a tissue microarray containing 169 invasive breast cancers to detect expression of β-catenin. One hundred thirty one of the 169 patients were followed up. Correlation between β-catenin expression and different molecular subtypes was determined using chi-square analysis. Overall survival (OS) was analyzed by Kaplan-Meier method with log-rank test. The invasive breast cancer displayed the different patterns of β-catenin expression from normal tissues with significantly increased cytoplasmic and nuclear staining of β-catenin. Aberrant β-catenin expression was observed in 109 in the 169 cases (64.50 %), and there was no difference in β-catenin expression in the four molecular subtypes. Furthermore, aberrant β-catenin expression was significantly associated with adverse outcome not only in the entire cohort but also in each of the different molecular subtypes. β-catenin activation is preferentially found and is associated with a poor clinical outcome in invasive breast cancer independent of molecular subtype.

DRP-1, ezrin and E-cadherin expression and the association with esophageal squamous cell carcinoma

It has been shown that death-associated protein kinase (DAPK) family and E-cadherin play significant roles in the promotion of apoptosis and the suppression of cell adhesion and migration, and are involved in tumor metastasis. Ezrin, a cytoplasmic peripheral membrane protein, has been shown to interact with E-cadherin to participate in the metastasis of tumor cells. The present study aimed to investigate the expression of DRP-1 (a member of the DAPK family), ezrin and E-cadherin in esophageal squamous cell carcinoma (ESCC), and to analyze their association with clinicopathological factors in order to explore their potential in ESCC diagnosis. The expression of these genes was studied in tissue microarrays using in situ hybridization and immunohistochemistry methods in 76 specimens of ESCC and their paracancerous normal squamous epithelium tissues. Expression was statistically analyzed with regard to clinicopathological factors using χ² and non-parametric tests. The expression level of DRP-1 was significantly different between the ESCC and paracancerous tissues (P<0.05). The expression level was correlated with the depth of invasion and lymph node metastasis (P<0.05). Abnormal E-cadherin expression was found to be associated with a high degree of cancer differentiation and lymph node metastasis (P<0.05). A positive correlation was observed between the expression of DRP-1 and E-cadherin (P<0.05). The expression of ezrin was found to be correlated with the depth of ESCC invasion, the degree of differentiation and lymph node metastasis (P<0.05). The high expression of ezrin has been previously shown to be correlated with the low or absent expression of E-cadherin. In conclusion, in ESCC, the expression levels of DRP-1, ezrin and E-cadherin were all reduced, and this reduction or absence of expression may have been attributed to ESCC tumorigenesis and progression. Simultaneous analyses of DRP-1, ezrin and E-cadherin expression levels would be useful to determine the malignancy and metastatic potential of ESCC, and these genes are consequently of potential use as biomarkers for the diagnosis and prognosis assessment of early-stage ESCC.

Induction of an EMT-like transformation and MET in vitro

Background

The epithelial-to-mesenchymal transition (EMT) and mesenchymal-to-epithelial transition (MET) play pivotal roles in metastasis of epithelial cancers. The distinction between them has shed new light on the molecular mechanisms of tumor metastasis. Recently, tumor microenvironment (TM) has been identified as one of the most potent inducers of EMT and MET. TM is characterized by its complexity and flexibility. The purpose of this study was to ascertain the exact effect of each distinct TM component on the evolution hepatocellular carcinoma (HCC) metastasis.

Methods

Two different cell culture models were used. The HCC cell line Bel-7402 was co-cultured with the normal liver cell line HL-7702 or with the retinal vascular endothelial cell line RF/6A in double-layer six-well plates, imitating the direct interaction between tumor-host cells and tumor cells. Bel-7402 was also cultured in the conditioned medium (CM) of the human lung fibroblast cell line MRC-5, HL-7702 or RF/6A, imitating an indirect interaction. Integrin β1, β3, β4, β7, laminin β3, E-cadherin and Snail levels were measured by quantitative RT-PCR in tumor sepecimens from 42 resected HCC.

Results

We found that Bel-7402 cells co-cultured with HL-7702 or RF/6A cells were induced to undergo MET. The expression of E-cadherin, α-catenin and β-catenin was up-regulated, accompanied with a strengthened E-cadherin/catenin complex on the membrane of co-cultured Bel-7402 cells. Consequently, the invasion and migration ability of cells was declined. Conversely, Bel-7402 cells cultured in conditioned medium from MRC-5 cells underwent an EMT-like transformation as the cells became elongated with increased invasion and migration ability. Furthermore, we demonstrated that HL-7702 cells could generally inhibit the tumorigenicity and viability of Bel-7402 cells. We also found that integrin β1 expression was negatively associated with capsular formation, and that integrin β4 expression was negatively associated with CK19 expression.

Conclusion

Our findings highlight the strong influences exerted by TM on tumor progression through EMT and MET by impacting the expression of adhesion molecules, including the E-cadherin/catenin complex, laminins and integrins.

Reduced expression levels of the death-associated protein kinase and E-cadherin are correlated with the development of esophageal squamous cell carcinoma

The aim of this study was to investigate the expression levels of the death-associated protein kinase (DAPK) and E-cadherin in esophageal squamous cell carcinoma (ESCC) and their correlation with clinical and pathological factors. Immunohistochemistry [streptavidin-peroxidase (SP) method], in situ hybridization, immunoblot assays and reverse transcription-PCR (RT-PCR) were used to detect the expression of DAPK and E-cadherin in the carcinomas and the adjacent normal tissues of 76 cases of esophageal squamous carcinomas. The immunoblot assay indicated that the expression levels of DAPK and E-cadherin were decreased significantly in the ESCC tissue (P<0.05) when compared with the adjacent normal tissues. The RT-PCR results showed that the mRNA levels of DAPK and E-cadherin were reduced. The abnormal expression of DAPK was highly correlated with the invasiveness and lymphatic metastasis of the cancer. The abnormal expression of E-cadherin was highly correlated with the differentiation and lymphatic metastasis of the cancer. The decreased expression levels of DAPK and E-cadherin correlated with the development of ESCC. The combined detection of DAPK and E-cadherin proteins may be correlated with the degree of malignancy and metastatic potency of ESCC.

Cadherin cell adhesion system in canine mammary cancer: a review

Cadherin-catenin adhesion complexes play important roles by providing cell-cell adhesion and communication in different organ systems. Abnormal expression of cadherin adhesion molecules constitutes a common phenomenon in canine mammary cancer and has been frequently implicated in tumour progression. This paper summarizes the current knowledge on cadherin/catenin adhesion molecules (E-cadherin, β-catenin, and P-cadherin) in canine mammary cancer, focusing on the putative biological functions and clinical significance of these molecules in this disease. This paper highlights the need for further research studies in this setting in order to elucidate the role of these adhesion molecules during tumour progression and metastasis.

Beta 1 integrin predicts survival in breast cancer: a clinicopathological and immunohistochemical study

Background

The main focus of several studies concerned with cancer progression and metastasis is to analyze the mechanisms that allow cancer cells to interact and quickly adapt with their environment. Integrins, a family of transmembrane glycoproteins, play a major role in invasive and metastatic processes. Integrins are involved in cell adhesion in both cell-extracellular matrix and cell-cell interactions, and particularly, β1 integrin is involved in proliferation and differentiation of cells in the development of epithelial tissues. This work aimed to investigate the putative role of β1 integrin expression on survival and metastasis in patients with breast invasive ductal carcinoma (IDC). In addition, we compared the expression of β1 integrin in patients with ductal carcinoma in situ (DCIS).

Methods

Through tissue microarray (TMA) slides containing 225 samples of IDC and 67 samples of DCIS, β1 integrin expression was related with several immunohistochemical markers and clinicopathologic features of prognostic significance.

Results

β1 integrin was overexpressed in 32.8% of IDC. In IDC, β1 integrin was related with HER-2 (p = 0.019) and VEGF (p = 0.011) expression and it had a significant relationship with metastasis and death (p = 0.001 and p = 0.05, respectively). Kaplan-Meier survival analysis showed that the overexpression of this protein is very significant (p = 0.002) in specific survival (number of months between diagnosis and death caused by the disease). There were no correlation between IDC and DCIS (p = 0.559) regarding β1 integrin expression.

Conclusions

Considering that the expression of β1 integrin in breast cancer remains controversial, specially its relation with survival of patients, our findings provide further evidence that β1 integrin can be a marker of poor prognosis in breast cancer.

Virtual slides

The virtual slide(s) for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/6652215267393871

Activation status of Wnt/ß-catenin signaling in normal and neoplastic breast tissues: relationship to HER2/neu expression in human and mouse

Wnt/ß-catenin signaling is strongly implicated in neoplasia, but the role of this pathway in human breast cancer has been controversial. Here, we examined Wnt/ß-catenin pathway activation as a function of breast cancer progression, and tested for a relationship with HER2/neu expression, using a human tissue microarray comprising benign breast tissues, ductal carcinoma in situ (DCIS), and invasive carcinomas. Cores were scored for membranous ß-catenin, a key functional component of adherens junctions, and for nucleocytoplasmic ß-catenin, a hallmark of Wnt/ß-catenin pathway activation. Only 82% of benign samples exhibited membrane-associated ß-catenin, indicating a finite frequency of false-negative staining. The frequency of membrane positivity was similar in DCIS samples, but was significantly reduced in carcinomas (45%, P<0.001), consistent with loss of adherens junctions during acquisition of invasiveness. Negative membrane status in cancers correlated with higher grade (P = 0.04) and estrogen receptor-negative status (P = 0.03), both indices of poor prognosis. Unexpectedly, a substantial frequency of nucleocytoplasmic ß-catenin was observed in benign breast tissues (36%), similar to that in carcinomas (35%). Positive-staining basal nuclei observed in benign breast may identify putative stem cells. An increased frequency of nucleocytoplasmic ß-catenin was observed in DCIS tumors (56%), suggesting that pathway activation may be an early event in human breast neoplasia. A correlation was observed between HER2/neu expression and nucleocytoplasmic ß-catenin in node-positive carcinomas (P = 0.02). Furthermore, cytoplasmic ß-catenin was detected in HER2/neu-induced mouse mammary tumors. The Axin2^NLSlacZ mouse strain, a previously validated reporter of mammary Wnt/ß-catenin signaling, was utilized to define in vivo transcriptional consequences of HER2/neu-induced ß-catenin accumulation. Discrete hyperplastic foci observed in mammary glands from bigenic MMTV/neu, Axin2^NLSlacZ mice, highlighted by robust ß-catenin/TCF signaling, likely represent the earliest stage of mammary intraepithelial neoplasia in MMTV/neu mice. Our study thus provides provocative evidence for Wnt/ß-catenin signaling as an early, HER2/neu-inducible event in breast neoplasia.

Mechanobiology of tumor invasion: engineering meets oncology

The physical sciences and engineering have introduced novel perspectives into the study of cancer through model systems, tools, and metrics that enable integration of basic science observations with clinical data. These methods have contributed to the identification of several overarching mechanisms that drive processes during cancer progression including tumor growth, angiogenesis, and metastasis. During tumor cell invasion - the first clinically observable step of metastasis - cells demonstrate diverse and evolving physical phenotypes that cannot typically be defined by any single molecular mechanism, and mechanobiology has been used to study the physical cell behaviors that comprise the "invasive phenotype". In this review, we discuss the continually evolving pathological characterization and in vitro mechanobiological characterization of tumor invasion, with emphasis on emerging physical biology and mechanobiology strategies that have contributed to a more robust mechanistic understanding of tumor cell invasion. These physical approaches may ultimately help to better predict and identify tumor metastasis.

β1-integrins signaling and mammary tumor progression in transgenic mouse models: implications for human breast cancer

Consistent with their essential role in cell adhesion to the extracellular matrix, integrins and their associated signaling pathways have been shown to be involved in cell proliferation, migration, invasion and survival, processes required in both tumorigenesis and metastasis. β1-integrins represent the predominantly expressed integrins in mammary epithelial cells and have been proven crucial for mammary gland development and differentiation. Here we provide an overview of the studies that have used transgenic mouse models of mammary tumorigenesis to establish β1-integrin as a critical mediator of breast cancer progression and thereby as a potential therapeutic target for the development of new anticancer strategies.

Tenascin C induces epithelial-mesenchymal transition-like change accompanied by SRC activation and focal adhesion kinase phosphorylation in human breast cancer cells

Tenascin C (TNC) is an extracellular matrix glycoprotein up-regulated in solid tumors. Higher TNC expression is shown in invading fronts of breast cancer, which correlates with poorer patient outcome. We examined whether TNC induces epithelial-mesenchymal transition (EMT) in breast cancer. Immunohistochemical analysis of invasive ductal carcinomas showed that TNC deposition was frequent in stroma with scattered cancer cells in peripheral margins of tumors. The addition of TNC to the medium of the MCF-7 breast cancer cells caused EMT-like change and delocalization of E-cadherin and β-catenin from cell-cell contact. Although amounts of E-cadherin and β-catenin were not changed after EMT in total lysates, they were increased in the Triton X-100-soluble fractions, indicating movement from the membrane into the cytosol. In wound healing assay, cells were scattered from wound edges and showed faster migration after TNC treatment. The EMT phenotype was correlated with SRC activation through phosphorylation at Y418 and phosphorylation of focal adhesion kinase (FAK) at Y861 and Y925 of SRC substrate sites. These phosphorylated proteins colocalized with αv integrin-positive adhesion plaques. A neutralizing antibody against αv or a SRC kinase inhibitor blocked EMT. TNC could induce EMT-like change showing loss of intercellular adhesion and enhanced migration in breast cancer cells, associated with FAK phosphorylation by SRC; this may be responsible for the observed promotion of TNC in breast cancer invasion.

CD151 amplifies signaling by integrin α6β1 to PI3K and induces the epithelial-mesenchymal transition in HCC cells

BACKGROUND & AIMS

Overexpression of CD151 is associated with poor prognosis for hepatocellular carcinoma (HCC), yet its role in pathogenesis is not known.

METHODS

We analyzed the expression of the integrin subunit α6 by quantitative, real-time polymerase chain reaction and immunoblot analyses of 120 HCC tissue samples; its clinical significance was investigated using tissue microarray (TMAs) analysis of samples from 335 patients with HCC. Immunoprecipitation was used to assess the relationship between α6 and CD151. The molecular effects of high expression levels of α6 and CD151 in HCC cells were determined using RNA interference and pharmacologic approaches.

RESULTS

Overexpression of α6 correlated with poor prognosis of patients with HCC; α6 formed a complex with endogenous CD151 in HCC cells. In cells that expressed high levels of α6 and CD151, laminin-5 promoted cell spreading by inducing the epithelial-mesenchymal transition (EMT); this effect was not observed in cells that expressed high levels of only α6 or CD151. Cells that expressed high levels of α6 and CD151 underwent the EMT in response to laminin-5, through hyperactivation of phosphatidylinositol-3-kinase (PI3K), primarily induced via the PI3K-protein kinase B (Akt)-Snail-phosphatase and tensin homolog feedback pathway. The EMT was reversed by PI3K inhibitors and antibodies against CD151 or α6 in vitro, and was delayed by specific interference with CD151 and α6 in vivo.

CONCLUSIONS

High expression levels of CD151 and α6 promote invasiveness of HCC cells. Either of these proteins, or PI3K signaling, might be targets for therapeutics for subgroups of patients with HCC.

Expression of Toll-like receptor 4 and beta 1 integrin in breast cancer

Toll-like receptor (TLR) 4 signaling pathway has been shown to support tumor cell growth in vitro and in vivo. Its stimulation on breast cancer cell lines induces β1 integrin and promotes tumor invasiveness. However, its role in predicting clinical behavior of tumor is not yet clarified. Therefore, we investigated TLR4 and β1 integrin expression on 133 primary breast cancer samples by immunohistochemistry and correlated it with overall survival and disease-free survival of patients as well as with clinicopathological characteristics of the tumor. We found higher β1 integrin expression in invasive lobular cancer in comparison with other tumor types. No significant association of TLR4 and β1 integrin expression with overall survival or disease-free survival was seen. Therefore, we conclude that expression of these markers is of biological interest but appears to be of little additional use as predictive clinical marker.

Immunohistochemical expression of E-cadherin in sclerosing adenosis, ductal carcinoma in situ and invasive ductal carcinoma of the breast

E-cadherin (EC) is an important glycoprotein cell-adhesion molecule that appears to play a significant role in the progression of breast lesions. The objective of this study was to evaluate EC expression in sclerosing adenosis, ductal carcinoma in situ and invasive ductal carcinoma. Samples of breast lesions from 44 women were used in this study, comprising cases of sclerosing adenosis (n = 11), ductal carcinoma in situ (DCIS) (n = 10) and invasive ductal carcinoma (n = 23). Immunohistochemical evaluation of EC expression was assessed semiquantitatively and considered negative (<10% of cells with stained cytoplasmic membranes), positive+ (10-50% of cells stained) or positive++ (> 50% of cells stained). Fisher's exact test was used to compare the distribution of staining intensity in the lesions (P< 0.05). There was a progressive loss of EC expression from benign to malignant lesions. This difference was statistically significant when sclerosing adenosis was compared with DCIS (P < 0.0002), when sclerosing adenosis was compared with invasive ductal carcinoma (P < 0.008) and when DCIS was compared with invasive ductal carcinoma (P < 0.007). The present findings point to a significant association between reduced EC expression and the progression and aggressivity of breast lesions. Diagn. Cytopathol. 2010. (c) 2009 Wiley-Liss, Inc.

miR-200 enhances mouse breast cancer cell colonization to form distant metastases

BACKGROUND

The development of metastases involves the dissociation of cells from the primary tumor to penetrate the basement membrane, invade and then exit the vasculature to seed, and colonize distant tissues. The last step, establishment of macroscopic tumors at distant sites, is the least well understood. Four isogenic mouse breast cancer cell lines (67NR, 168FARN, 4TO7, and 4T1) that differ in their ability to metastasize when implanted into the mammary fat pad are used to model the steps of metastasis. Only 4T1 forms macroscopic lung and liver metastases. Because some miRNAs are dysregulated in cancer and affect cellular transformation, tumor formation, and metastasis, we examined whether changes in miRNA expression might explain the differences in metastasis of these cells.

METHODOLOGY/PRINCIPAL FINDINGS

miRNA expression was analyzed by miRNA microarray and quantitative RT-PCR in isogenic mouse breast cancer cells with distinct metastatic capabilities. 4T1 cells that form macroscopic metastases had elevated expression of miR-200 family miRNAs compared to related cells that invade distant tissues, but are unable to colonize. Moreover, over-expressing miR-200 in 4TO7 cells enabled them to metastasize to lung and liver. These findings are surprising since the miR-200 family was previously shown to promote epithelial characteristics by inhibiting the transcriptional repressor Zeb2 and thereby enhancing E-cadherin expression. We confirmed these findings in these cells. The most metastatic 4T1 cells acquired epithelial properties (high expression of E-cadherin and cytokeratin-18) compared to the less metastatic cells.

CONCLUSIONS/SIGNIFICANCE

Expression of miR-200, which promotes a mesenchymal to epithelial cell transition (MET) by inhibiting Zeb2 expression, unexpectedly enhances macroscopic metastases in mouse breast cancer cell lines. These results suggest that for some tumors, tumor colonization at metastatic sites might be enhanced by MET. Therefore the epithelial nature of a tumor does not predict metastatic outcome.

Real time PCR analyses of expression of E-cadherin, alpha-, beta- and gamma-catenin in human breast cancer for predicting clinical outcome

Background

The E-cadherin catenin system acts as an invasion suppressor of epithelial malignancies. However, it is debatable whether expression of E-cadherin or catenins is a useful prognostic marker in invasive breast cancer.

Methods

We measured the expression of E-cadherin and catenins (α-, β-, γ-catenin) in human breast carcinomas using real time quantitative polymerase chain reaction (Q-PCR) and investigated whether the expression levels were associated with known tumour variables or patient survival (median follow-up 72.2 months). RNA from frozen sections of breast tissue (tumour n = 124, background normal tissue n = 33) was reverse transcribed, quantified and analysed by Q-PCR with results expressed as number of copies of transcript/50 ng RNA.

Results

There was no statistically significant difference in the expression of E-cadherin and catenins (α-, β-, γ-catenin)in the 33 paired normal background and tumour tissues. The expression of E-cadherin, α-, β-, and γ-catenin in node positive tumours was similar to node-negative tumours. E-cadherin, α-, β-, and γ-catenin expression in breast tumours was not related to Nottingham Prognostic Index (NPI). There was no significant difference in the expression of E-cadherin, α-, β-, γ-catenin between the various TNM stages. None of the molecular markers significantly influenced survival. Lymph node status was the only significant predictor of survival.

Conclusion

Using real time quantitative PCR there was no difference in the expression of E-cadherin, α-, β-, γ-catenin between tumour and normal breast tissue. Furthermore, measurement of expression of these molecules was not of prognostic value in predicting long term outcome of women with breast cancer.

Genomics and premalignant breast lesions: clues to the development and progression of lobular breast cancer

Advances in genomic technology have improved our understanding of the genetic events that parallel breast cancer development. Because almost all mammary carcinomas develop in the terminal duct lobular units of the breast, understanding the events involved in mammary gland development make it possible to recognize those events that, when altered, contribute to breast neoplasia. In this review we focus on lobular carcinomas, discussing the pathology, development, and progression of premalignant lobular lesions from a genomic point of view. We highlight studies utilizing genomic approaches and describe how these investigations have furthered our understanding of the complexity of premalignant breast lesions.

P-cadherin and beta-catenin are useful prognostic markers in breast cancer patients; beta-catenin interacts with heat shock protein Hsp27

The cadherin-catenin proteins have in common with heat shock proteins (HSP) the capacity to bind/interact proteins of other classes. Moreover, there are common molecular pathways that connect the HSP response and the cadherin-catenin protein system. In the present study, we have explored whether in breast cancer the HSP might interact functionally with the cadherin-catenin cell adhesion system. Beta-catenin was immunoprecipitated from breast cancer biopsy samples, and the protein complexes isolated in this way were probed with antibodies against HSP family members. We are thus the first to demonstrate a specific interaction between beta-catenin and Hsp27. However, beta-catenin did not bind Hsp60, Hsp70, Hsp90, gp96, or the endoplasmic reticulum stress response protein CHOP. To confirm the finding of Hsp27-beta-catenin interaction, the 27-kDa immunoprecipitated band was excised from one-dimensional polyacrylamide gel electrophoresis gels and submitted to liquid chromatography-tandem mass spectrometry with electrospray ionization, confirming a role for Hsp27. In addition, beta-catenin interacted with other proteins including heat shock transcription factor 1, P-cadherin, and caveolin-1. In human breast cancer biopsy samples, beta-catenin was coexpressed in the same tumor areas and in the same tumor cells that expressed Hsp27. However, this coexpression was strong when beta-catenin was present in the cytoplasm of the tumor cells and not when beta-catenin was expressed at the cell surface only. Furthermore, murine breast cancer cells transfected with hsp25 showed a redistribution of beta-catenin from the cell membrane to the cytoplasm. When the prognostic significance of cadherin-catenin expression was examined by immunohistochemistry in breast cancer patients (n = 215, follow-up = >10 years), we found that the disease-free survival and overall survival were significantly shorter for patients expressing P-cadherin and for patients showing expression of beta-catenin in the cytoplasm only (not at the cell surface). The interactions of beta-catenin with Hsp27 and with HSF1 may explain some of the molecular pathways that influence tumor cell survival and the clinical significance in the prognosis of the breast cancer patients.

Reassessing epithelial to mesenchymal transition as a prerequisite for carcinoma invasion and metastasis

For most carcinomas, progression toward malignancy is accompanied by loss of epithelial differentiation and a shift towards a mesenchymal phenotype. This process, referred to as epithelial to mesenchymal transition (EMT), exacerbates motility and invasiveness of many cell types and is often considered a prerequisite for tumor infiltration and metastasis. However, there are numerous examples of advanced carcinomas that adopt some mesenchymal features, yet retain characteristics of well-differentiated epithelial cells. We provide a review of these reports and describe mechanisms to explain the morphologic and molecular heterogeneity and plasticity of malignant carcinoma cells, including incomplete EMT, reversion to an epithelial phenotype, and collective migration. We suggest that these mechanisms can manifest in a series of independent and reversible steps and that EMT represents just one mechanism in the global metastatic carcinoma development process.

Bench to bedside and back again: molecular mechanisms of alpha-catenin function and roles in tumorigenesis

The cadherin/catenin complex, comprised of E-cadherin, beta-catenin and alpha-catenin, is essential for initiating cell-cell adhesion, establishing cellular polarity and maintaining tissue organization. Disruption or loss of the cadherin/catenin complex is common in cancer. As the primary cell-cell adhesion protein in epithelial cells, E-cadherin has long been studied in cancer progression. Similarly, additional roles for beta-catenin in the Wnt signaling pathway has led to many studies of the role of beta-catenin in cancer. Alpha-catenin, in contrast, has received less attention. However, recent data demonstrate novel functions for alpha-catenin in regulating the actin cytoskeleton and cell-cell adhesion, which when perturbed could contribute to cancer progression. In this review, we use cancer data to evaluate molecular models of alpha-catenin function, from the canonical role of alpha-catenin in cell-cell adhesion to non-canonical roles identified following conditional alpha-catenin deletion. This analysis identifies alpha-catenin as a prognostic factor in cancer progression.

The Spectrum of Morphomolecular Abnormalities of the E-Cadherin/Catenin Complex in Pleomorphic Lobular Carcinoma of the Breast

Pleomorphic lobular carcinoma of the breast is a high nuclear grade variant of lobular carcinoma. E-cadherin, a tumor-invasion suppressor gene, codes for a transmembrane protein that functions in intercellular adhesion. The E-cadherin protein internal domain binds with alpha, beta, gamma, and p120 catenins to anchor the E-cadherin complex to the actin cytoskeleton of the cell. The E-cadherin gene is routinely mutated in lobular neoplasia. This study examines the morphomolecular spectrum of the components of the E-cadherin-catenin complex in lobular neoplasia. Fifteen cases of pleomorphic lobular neoplasia, 8 cases of classic lobular neoplasia and 4 ductal carcinomas were studied. Normal breast epithelium and invasive ductal carcinomas all showed intense linear cell membrane immunostaining with antibodies to E-cadherin, alpha, beta, gamma, and P120 catenins. Membrane immunostaining of the catenin antibodies in lobular neoplasia was negative, except for rare cases that displayed beaded or dotlike patterns. Cytoplasmic immunostaining patterns for all lobular lesions included coarse paranuclear granules of beta catenin or diffuse intense cytoplasmic staining for P120 catenin. These immunostaining patterns demonstrate that catenins alpha, beta, gamma, and p120 are routinely dislocated from the cell membrane into the cytoplasm in lobular neoplasia and that the disrupted catenin patterns parallel absence of membrane E-cadherin in all cases. The diffuse cytoplasmic immunostaining of p120 in lobular neoplasia may be useful diagnostically as a positive marker for lobular neoplasia.

Adherens and tight junctions: structure, function and connections to the actin cytoskeleton

Adherens junctions and Tight junctions comprise two modes of cell-cell adhesion that provide different functions. Both junctional complexes are proposed to associate with the actin cytoskeleton, and formation and maturation of cell-cell contacts involves reorganization of the actin cytoskeleton. Adherens junctions initiate cell-cell contacts, and mediate the maturation and maintenance of the contact. Adherens junctions consist of the transmembrane protein E-cadherin, and intracellular components, p120-catenin, beta-catenin and alpha-catenin. Tight junctions regulate the paracellular pathway for the movement of ions and solutes in-between cells. Tight junctions consist of the transmembrane proteins occludin and claudin, and the cytoplasmic scaffolding proteins ZO-1, -2, and -3. This review discusses the binding interactions of the most studied proteins that occur within each of these two junctional complexes and possible modes of regulation of these interactions, and the different mechanisms that connect and regulate interactions with the actin cytoskeleton.

Expression of E-cadherin, P-cadherin and beta-catenin in canine malignant mammary tumours in relation to clinicopathological parameters, proliferation and survival

Cadherin-catenin complexes play a critical role in intercellular adhesion, and their altered expression has been implicated in tumour progression. In this study, the expression of E-cadherin, P-cadherin and beta-catenin was analysed in 65 canine malignant mammary tumours and correlated with clinicopathological parameters, proliferation and survival. Reduction in E-cadherin expression was significantly associated with increased tumour size, high histological and invasion grades, lymph node metastasis and high mitotic index. Reduced beta-catenin expression was associated with high histological and invasion grades. Anomalous expression of P-cadherin was only associated with invasion. In 39 cases for which follow-up data were available, reduced E-cadherin and beta-catenin expression was significantly associated with shorter overall survival and disease free survival. Abnormal expression of adhesion molecules is a common phenomenon in canine mammary malignant tumours and may play a central role in tumour progression.

E-cadherin, beta-catenin, invasion and lymph node metastases in canine malignant mammary tumours

Recent studies of canine malignant mammary tumours suggest that reduction of E-cadherin and/or beta-catenin correlates with invasive behaviour and lymph node metastasis. The aims of this study were to examine the interrelationships between the expression of E-cadherin and beta-catenin, and the relationship between the expression of E-cadherin and/or beta-catenin and the mode of growth and metastatic capacity of canine malignant mammary tumours. 90 spontaneous malignant tumours and local and regional lymph nodes were studied. A significant relationship was evidenced between membranous expression of E-cadherin and beta-catenin (p=0.0027), but not between E-cadherin and cytoplasmic beta-catenin. Only E-cadherin as a separate factor was significantly related to tumour invasion (p=0.0072) and lymph node metastasis (p=0.0001). Neither membranous nor cytoplasmic beta-catenin expression was significantly related to either of these phenomena.

Increased β1 Integrin Is Associated with Decreased Survival in Invasive Breast Cancer

Aberrant microenvironments and loss of balance in cell-extracellular matrix signaling are associated with breast cancer invasion, metastasis, and resistance to therapy. We have recently shown that increased beta1 integrin signaling is involved in malignant progression and that inhibitory antibody to beta1 integrin leads to selective apoptosis and decreased proliferation in three-dimensional cultures and in xenograft models of breast cancer in vivo. To investigate the clinical importance of these findings, in the present study we examined the expression of beta1 integrin and extracellular beta1 integrin ligands fibronectin and laminin-1 in a cohort of 249 breast cancer patients who had a median follow-up of 8.4 years. Among the 149 scorable cases, the highest beta1 integrin intensity score (3+ versus 0-2+) was associated with significantly decreased 10-year overall survival of 48% versus 71% (P<0.03) and decreased disease-free survival of 50% versus 80% (P<0.05). Importantly, high fibronectin expression was associated with decreased overall and disease-free survival on univariate analysis (P<0.04) and beta1 integrin intensity score was significantly correlated with fibronectin expression (Kendall's tau-b=0.19; P=0.03). In a multivariate Cox proportional hazards model, beta1 integrin intensity score remained a significant independent predictor of overall survival [hazard ratio (HR), 1.69; 95% confidence interval (95% CI), 1.19-2.38; P<0.003] and disease-free survival (HR, 1.87; 95% CI, 1.21-2.88; P<0.005). These findings show that beta1 integrin expression has potential prognostic value in invasive breast cancer and that coexpression of fibronectin may help identify patients with more aggressive tumors who may benefit from targeted therapy.

Chronic NOS inhibition actuates endothelial-mesenchymal transformation

Chronic kidney diseases are accompanied by the accumulation of substances like asymmetric dimethylarginine, phenylacetic acid, homocysteine, and advanced glycation end products, known to either inhibit endothelial nitric oxide synthase (eNOS) or uncouple it, consequently limiting the amount of available nitric oxide (NO). Reduced bioavailability of NO induces endothelial dysfunction. An early loss of peritubular capillaries in tubulointerstitial fibrotic areas and injury to endothelial cells have been linked to progressive renal disease. Screening endothelial genes in cells treated with NOS inhibitors showed upregulation of collagen XVIII, a precursor of a potent antiangiogenic substance, endostatin. This finding was confirmed at the level of mRNA and protein expression. Tie-2 promoter-driven green fluorescent protein mice treated with nonhypertensinogenic doses of a NOS inhibitor exhibited upregulation of collagen XVIII/endostatin and rarefaction of capillary profiles. This was accompanied by the increased expression of transforming growth factor-β and connective tissue growth factor in the kidney. Occasional endothelial cells expressed both the marker of endothelial lineage (green fluorescent protein) and mesenchymal marker (α-smooth muscle actin or calponin). In vitro studies of endothelial cells treated with asymmetric dimethylarginine showed decreased expression of eNOS and Flk-1 and enhanced expression of calponin and fibronectin, additional markers of smooth muscle and mesenchymal cells. These cells overexpressed transforming growth factor-β and connective tissue growth factor, as well as endostatin. In conclusion, data presented here 1) ascribe to NO deficiency in endothelial cells the function of a profibrotic stimulus associated with the expression of an antiangiogenic fragment of collagen XVIII (endostatin) and 2) provide evidence of endothelial-mesenchymal transdifferentiation in the course of inhibition of NOS by a pathophysiologically important antagonist, asymmetric dimethylarginine. Both mechanisms may account for microvascular rarefaction.

Metastasis-related factors expressed in pT1 pN0 breast cancer: Assessment of recurrence risk

OBJECTIVES

Previous reports have indicated that small breast cancers without lymph node metastasis present a favorable prognosis. However, 10-20% of patients with T1 N0 invasive ductal carcinoma experience recurrence and have a poor prognosis. The objective of this study was to examine whether certain metastasis-related factors are prognostic of cancer recurrence in such patients at risk for relapse.

METHODS

Nineteen patients with the carcinoma who had recurrence 1-15 years after margin-free resection were examined. The control group consisted of 20 patients with pT1 pN0 invasive ductal carcinoma who had no recurrence for > or =10 years after radical surgery. The two groups were compared with respect to clinical profiles, conventional neoplastic features, and immunohistochemical expressions of 16 metastasis-related factors.

RESULTS

No significant difference was found between the two groups in clinical profiles and conventional neoplastic features. However, six factors (MMP-2, MT1-MMP, T1MP-2, VEGF, cMET, and PCNA) were significantly expressed in the recurrence group against the control group. MMP-9 was significantly less expressed in the recurrence group. Of these factors, MMP-2, MT1-MMP, and VEGF showed the highest adjusted odds ratios.

CONCLUSION

MMP family and growth factors may be promising predictors of recurrence risk of early stage breast cancer.

Lymph node status as a guide to selection of available prognostic markers in breast cancer: the clinical practice of the future?

Prognosticators evaluating survival in breast cancer vary in significance in respect to lymph node status. Studies have shown e.g. that HER2/neu immunohistochemistry or HER2/neu gene amplification analysis do perform well as prognosticators in lymph node positive (LN +) patients but are less valuable in lymph node negative (LN -) patients. We collected data from different studies and tried to evaluate the relative significance of different prognosticators in LN+/LN- patient groups. In LN+ patients HER2/neu and E-cadherin immunohistochemistry were the statistically most significant prognosticators followed by proliferation associated features (mitotic counts by SMI (standardised mitotic index) or MAI (mitotic activity index), or S-phase fraction). Bcl-2 immunohistochemistry was also significant but p53 and cystatin A had no significance as prognosticators. In LN- patients proliferation associated prognosticators (SMI, MAI, Ki-67 index, PCNA immunohistochemistry, S-phase fraction) are especially valuable and also Cathepsin D, cystatin A, and p53 are significant, but HER2/neu or bcl-2, or E-cadherin less significant or without significance. We find that in studies evaluating single prognosticators one should distinguish between prognosticators suitable for LN+ and LN- patients. This will allow the choice of best prognosticators in evaluating the prospects of the patient. The distinction between LN+ and LN- patients in this respect may also be of special value in therapeutic decisions.

E-cadherin Immunohistochemical Expression as a Prognostic Factor in Infiltrating Ductal Carcinoma of the Breast: a Systematic Review and Meta-Analysis

PURPOSE

Multiple studies examining the relationship between loss of E-cadherin expression, a pivotal event for evolving metastatic behavior among epithelially derived cancers, and 5-year survival in infiltrating ductal breast carcinoma have yielded inconclusive and contradictory results.

EXPERIMENTAL DESIGN

We conducted a systematic review of the PubMed database through August 2005 with no language restrictions to identify cohort studies that evaluated E-cadherin immunohistochemical expression as a prognostic marker for ductal breast carcinoma. 5-year all-cause mortality or 5-year breast cancer-specific mortality were the primary study outcomes. Meta-analysis was conducted using the REVMAN software and summary hazard ratios assuming both fixed effect and random effect models were calculated.

RESULTS

Ten retrospective cohort studies were identified. Reduced or absent E-cadherin expression significantly increased the risk of all-cause mortality [combined HR = 1.55; 95% CI = 1.08-2.23] whereas a non-significant association was observed for breast cancer-specific mortality [combined HR = 0.70; 95% CI = 0.39-1.27]. We documented substantial inter-study heterogeneity with respect to all aspects of clinical data collection, immunohistochemical staining and interpretation as well as statistical modeling. These factors could not be formally analyzed but they challenge the robustness of our calculated summary estimates.

CONCLUSIONS

Loss of E-cadherin expression may be an independent negative prognostic indicator for infiltrating ductal breast carcinoma and randomized, controlled studies evaluating this finding are justified. We encourage standardization of immunohistochemical techniques, data interpretation algorithms across laboratories and use of all-cause mortality to increase data compatibility and facilitate future efforts summarizing the utility of alternate prognostic markers in cancer.

E-cadherin expression in canine malignant mammary tumours: relationship to other clinico-pathological variables

The relationship between E-cadherin epithelial expression, as detected by immunohistochemical methods, and other clinico-pathological characteristics of canine malignant mammary tumours was studied in 77 tumours surgically removed from 45 female dogs. The immunohistochemical assessment was based on the estimated percentage of epithelial cells with membranous labelling. Reduction of E-cadherin expression was significantly related to size and ulceration of tumours but not to fixation to skin or underlying tissue; it was also related to lymph node metastasis, necrosis and infiltrative growth. Histological type (but not histological grade) was related to E-cadherin expression, with solid tumours more frequently lacking expression and tubulopapillary tumours showing increased expression as compared with the other types. The significant relationship between E-cadherin and other known factors of poor prognosis suggests that the loss of E-cadherin expression may have prognostic value in canine malignant mammary tumours.