Expression of CD44 isoforms in infiltrating lobular carcinoma of the breast

Novel evaluation of the expression patterns CD44 and MMP9 proteins in intracranial meningiomas and their relationship to the overall survival

Background

Meningiomas are common primary brain neoplasms. CD44 is a cell surface glycoprotein receptor that is involved in matrix-mediated cell signaling and cell–matrix adhesion. Matrix metalloproteinase-9 (MMP-9) plays important role in angiogenesis and tumor invasion. The expression of CD44 protein membranous and cytoplasmic (CD44M and CD44C) has been reported in several tumors (such as lobular carcinoma, renal cell carcinoma, sinonasal melanoma, and lymphoma) except CNS tumors.

Methods

This study addressed the expression of CD44M and CD44C and MMP9 proteins in intracranial meningiomas and their relationship to overall survival. The expression patterns of CD44M&C and MMP-9 proteins were examined in 32 cases of benign meningiomas, 12 cases of atypical meningiomas, and 6 cases of anaplastic meningiomas using immunohistochemical staining methods.

Results

There was more evidence of CD44M expression in atypical and anaplastic meningioma (p =  < 0.001). Interestingly, Spearman correlation analyses revealed significant positive correlation between CD44M and MMP9 protein (r = 0.572, p =  < 0.001) in spite of the negative correlation between MMP9 and CD44 score (r = − 0.035 p = 0.405). There was a significant association between Ki67 protein expression and the grade of meningiomas (p < 0.001) and gender (p = 0.026). There was a significant correlation between overall survival (OS) and age, gender, tumor grade, and Ki-67.

Conclusions

Extensive CD44M expression in high-grade meningioma may reflect a tendency toward more invasive power of meningioma cells into surrounding structures (dura, bone, and brain).CD44M/MMP-9 axis presented by this study is open for future investigations.

Collective invasion in ductal and lobular breast cancer associates with distant metastasis

Breast cancer undergoes collective tissue invasion and, in experimental models, can collectively metastasize. The prevalence of collective invasion and its contribution to distant metastasis in clinical disease, however, remains poorly defined. We here scored the adipose tissue invasion of primary invasive ductal carcinoma (IDC), expressing E-cadherin, and E-cadherin negative invasive lobular carcinoma (ILC) and identified predominantly collective invasion patterns (86/86 samples) in both carcinoma types. Whereas collective invasion in IDC lesions retained adherens junctions, multicellular clusters and “Indian files” in ILC, despite the absence of adherens junctions (AJ) proteins E-cadherin and β-catenin, retained CD44 at cell–cell contacts. By histomorphological scoring and semi-automated image analysis, we show that the extent of collective invasion into the adipose tissue correlated with decreased distant metastasis-free survival (5-year follow-up; hazard ratio: 2.32 and 2.29, respectively). Thus, collective invasion represents the predominant invasion mode in breast cancer, develops distinct junctional subtypes in IDC and ILC, and associates with distant metastasis, suggesting a critical role in systemic dissemination.

High throughput identification of monoclonal antibodies to membrane bound and secreted proteins using yeast and phage display

Antibodies are ubiquitous and essential reagents for biomedical research. Uses of antibodies include quantifying proteins, identifying the temporal and spatial pattern of expression in cells and tissue, and determining how proteins function under normal or pathological conditions. Specific antibodies are only available for a small portion of the proteome, limiting study of those proteins for which antibodies do not exist. The technologies to generate target-specific antibodies need to be improved to obtain high quality antibodies to the proteome at reasonable cost. Here we show that renewable, validated, and standardized monoclonal antibodies can be generated at high throughput, without the need for antigen production or animal immunizations. In this study, 60 protein domains from 24 selected secreted proteins were expressed on the surface of yeast and used for selection of phage antibodies, over 400 monoclonal antibodies were identified within 3 weeks. A subset of these antibodies was validated for binding to cancer cells that overexpress the target protein by flow cytometry or immunohistochemistry. This approach will be applicable to many of the membrane-bound and the secreted proteins, 20–40% of the proteome, accelerating the timeline for Ab generation while reducing the cost.

DNA aptamers against exon v10 of CD44 inhibit breast cancer cell migration

CD44 adhesion molecules are expressed in many breast cancer cells and have been demonstrated to play a key role in regulating malignant phenotypes such as growth, migration, and invasion. CD44 is an integral transmembrane protein encoded by a single 20-exon gene. The diversity of the biological functions of CD44 is the result of the various splicing variants of these exons. Previous studies suggest that exon v10 of CD44 plays a key role in promoting cancer invasion and metastasis, however, the molecular mechanisms are not clear. Given the fact that exon v10 is in the ectodomain of CD44, we hypothesized that CD44 forms a molecular complex with other cell surface molecules through exon v10 in order to promote migration of breast cancer cells. In order to test this hypothesis, we selected DNA aptamers that specifically bound to CD44 exon v10 using Systematic Evolution of Ligands by Exponential Enrichment (SELEX). We selected aptamers that inhibited migration of breast cancer cells. Co-immunoprecipitation studies demonstrated that EphA2 was co-precipitated with CD44. Pull-down studies demonstrated that recombinant CD44 exon v10 bound to EphA2 and more importantly aptamers that inhibited migration also prevented the binding of EphA2 to exon v10. These results suggest that CD44 forms a molecular complex with EphA2 on the breast cancer cell surface and this complex plays a key role in enhancing breast cancer migration. These results provide insight not only for characterizing mechanisms of breast cancer migration but also for developing target-specific therapy for breast cancers and possibly other cancer types expressing CD44 exon v10.

CD44 is overexpressed in basal-like breast cancers but is not a driver of 11p13 amplification

Overexpression and alternative splicing of CD44 have been implicated in tumour progression. Here we describe the identification of a high level amplification of human 11p13, encompassing the CD44 gene, in primary breast cancers and cell lines and test whether CD44 acts as the driver of this amplicon. aCGH analysis revealed 11p13 amplification in 3% (3/100) of primary breast carcinomas and in two cell lines. The minimal region of amplification was 34.38-37.62 Mb. Amplification was confirmed by dual-colour FISH in these cell lines and further validated by CISH in an independent tumour cohort. CD44 expression in primary breast cancers was significantly associated with features of basal-like breast cancer. Detection of CD44 expression in breast cancer cell lines confirmed moderate to high expression in basal-like cell lines and minimal expression in luminal cell lines. In both, primary breast cancers and cell lines, 11p13 amplification was associated with high levels of CD44 mRNA expression. CD44 alternative splicing was detected in four of nine cell lines and in tumour samples, irrespective of the amplification status. RNAi mediated knock down of CD44 failed to reveal an increased dependence on CD44 expression for proliferation or survival in amplified cell lines. Given that expression of CD44 is not an absolute requirement for the survival of cells harbouring CD44 gene amplification, CD44 is unlikely to be a driver of the 11p13 amplicon.

Serial transplantation of NMU-induced rat mammary tumors: A model of human breast cancer progression

Human breast cancer is a heterogeneous disease that appears to progress from an in situ tumor to invasive cancer. Little is known about the molecular events driving this progression. Although microarray technology has helped us understand the genetic heterogeneity of breast cancer, its application to studying the transition from in situ to invasive disease is limited by the inability to follow the progression of a single patient's tumor. We previously used rat specific microarrays to show that N-methyl-N-nitrosourea induced tumors are similar to low-grade estrogen-receptor positive human breast cancer. Here, we transplanted these tumors through 5 generations of syngeneic hosts, and studied 65 resulting tumors. Most transplanted tumors gradually progressed from a noninvasive, low-grade cancer to a higher-grade invasive disease, losing p63 localization and basement membrane integrity. Invasive cancers frequently demonstrated a more mesenchymal phenotype with increased vimentin expression. Additionally, a unique transplant series is described with a phenotype similar to human basal-like breast cancer. Rat-specific Affymetrix gene arrays containing 15,866 gene probes identified genes that differentiated highly invasive tumors from those of low invasive potential. A linear regression analysis was used to find genes whose change in expression paralleled increasing invasive features independent of the transplant lineage of origin. Genes identified were assigned membership in cell adhesion, signal transduction, cell cycle and extracellular matrix groups, among others. This animal model overcomes the difficulty in studying human breast cancer progression. Our data support a gradual and continuous alteration in programs of gene expression during breast cancer invasion.

Biologic markers in axillary node-negative breast cancer: differential expression in invasive ductal carcinoma versus invasive lobular carcinoma

PURPOSE

The objective of this study was to compare the differential expression of established histopathologic and biologic markers of proliferation, apoptosis, and angiogenesis in invasive lobular carcinoma (ILC) and invasive ductal carcinoma (IDC) in a group of axillary node-negative breast cancers.

PATIENTS AND METHODS

Two hundred twenty patients with axillary node-negative ILC and IDC who underwent surgery at the University of Texas M. D. Anderson Cancer Center between 1978 and 1995 had tissue available for analysis. Of these, 206 (94%) had IDC and 14 (6%) had ILC. Estrogen receptors, progesterone receptors, tumor and stromal expression of vascular endothelial growth factor receptor 2, CD44, laminin-5, E-cadherin, and topoisomerase-2 were evaluated by immunohistochemical analysis. HER2/neu and alpha6beta4 integrin were evaluated by in situ hybridization. The Fisher exact test was used to calculate significant differences between ILC and IDC. Median age was 59 years.

RESULTS

Invasive lobular carcinoma was more likely to occur in patients aged > 50 years. Invasive lobular carcinoma tended to be > 2 cm (50% vs. 39%), have a nuclear grade of 1/2 (100% vs. 72%), be estrogen receptor positive (93% vs. 70%), HER2/neu negative (92% vs. 68%), have high CD44 expression (31% vs. 16%), low stromal vascular endothelial growth factor receptor 2 expression (36% vs. 47%), no E-cadherin expression (0 vs. 90%), and low laminin-5 expression (15% vs. 25%), compared with IDC.

CONCLUSION

Invasive lobular carcinoma and IDC might be distinct histologic types of breast cancer with different expression of biologic markers. These differences, not all being statistically significant in this small study, might generate hypotheses to develop tailored options for future systemic therapy.

Cortactin underpins CD44-promoted invasion and adhesion of breast cancer cells to bone marrow endothelial cells

Using a validated tetracycline (tet)-regulated MCF7-founder (MCF7F) expression system to modulate expression of CD44 standard form (CD44s), we report the functional importance of CD44s and that of a novel transcriptional target of hyaluronan (HA)/CD44s signaling, EMS1/cortactin, in underpinning breast cancer metastasis. In functional experiments, tet-regulated induction of CD44s potentiated the migration and invasion of MCF7F cells through HA-supplemented Matrigel. EMS1/cortactin was identified by expression profiling as a novel transcriptional target of HA/CD44 signaling, an association validated by quantitative PCR and immunoblotting experiments in a range of breast cancer cell lines. The mechanistic basis underpinning CD44-promoted transcription of EMS1/cortactin was shown to be dependent upon a NFkappaB mechanism, since pharmacological inhibition of IkappaKinase-2 or suppression of p65 Rel A expression attenuated CD44-induced increases in cortactin mRNA transcript levels. Overexpression of a c-myc tagged murine cortactin construct in the weakly invasive, CD44-deficient MCF7F and T47D cells potentiated their invasion. Furthermore, the functional importance of cortactin to CD44s-promoted metastasis was demonstrated by selective suppression of cortactin in CD44-expressing MCF7F-B5 and MDA-MB-231 breast cancer cells using RNAi, which was shown to result in attenuated CD44-promoted invasion and CD44-promoted adhesion to bone marrow endothelial cells (BMECs).

Comparison of immunohistological parameters in primary breast cancers and corresponding locoregional recurrences

Biological changes in breast cancers during tumor progression can affect therapeutic parameters, such as hormone receptors. We studied a series of primary tumors and the matching recurrent lesions to analyze the frequency of this phenomenon and the impact on disease-free interval. The expression of ER, PgR, c-erbB2, CD44v6, and p53 in the primary and the locoregional tumor was analyzed in 70 patients with recurrent breast cancer. Antigen expression correlated well between the primary and the matching recurrent tumor for all antigens under study. However, hormone receptor expression was lost in more than 50% of the cases, without significant impact on the disease-free survival interval. The disease-free interval was significantly longer for PgR-positive primary tumors, but did not depend on the ER status. The expression or changes of c-erbB2, CD44v6, and p53 were not related to the recurrence-free time intervals. Therefore, for treatment, it seems important to consider a possible loss of hormone receptors during tumor progression.

CD44s is useful in the differentiation of benign and malignant papillary lesions of the breast

BACKGROUND/AIMS

CD44s, the standard form of CD44, has been shown to be downregulated during malignant transformation of breast cancers. It has also been reported recently to be a useful marker in differentiating between benign and malignant papillary lesions of the breast, with high expression in the former. CD44s expression in benign and malignant papillary lesions was evaluated.

METHODS

CD44s expression was assessed by immunohistochemistry in 101 benign papillomas and 59 papillary carcinomas (seven invasive papillary carcinomas, 41 papillary ductal carcinomas in situ, and 11 ductal carcinomas involving papillomas).

RESULTS

Patients' age and tumour size were significantly different between the papilloma and papillary carcinoma groups (p < 0.0001). CD44s showed positive staining in 45 papillomas (45%) and five papillary carcinomas (8%), and the difference was significant (p < 0.0001). The myoepithelial cells, when present, were also positive for CD44s in both groups, with no observable differences. Using CD44s positive staining to differentiate between benign and malignant papillary lesions gives a sensitivity, specificity, and accuracy of 45%, 92%, and 62%, respectively.

CONCLUSIONS

CD44s may be useful as an adjunct in the evaluation of morphologically problematic cases of papillary lesion of the breast.

Expression and significance of CD44s, CD44v6, and nm23 mRNA in human cancer

AIM: To investigate the relationship between the expression levels of nm23 mRNA, CD44s, and CD44v6, and oncogenesis, development and metastasis of human gastric adenocarcinoma, colorectal adenocarcinoma, intraductal carcinoma of breast, and lung cancer.

METHODS: Using tissue microarray by immu-histochemical (IHC) staining and in situ hybri-dization (ISH), we examined the expression levels of nm23 mRNA, CD44s, and CD44v6 in 62 specimens of human gastric adenocarcinoma and 62 specimens of colorectal adenocarcinoma; the expression of CD44s and CD44v6 in 120 specimens of intraductal carcinoma of breast and 20 specimens of normal breast tissue; the expression of nm23 mRNA in 72 specimens of human lung cancer and 23 specimens of normal tissue adjacent to cancer.

RESULTS: The expression of nm23 mRNA in the tissues of gastric and colorectal adenocarcinoma was not significantly different from that in the normal tissues adjacent to cancer (P>0.05), and was not associated with the invasion of tumor and the pathology grade of adenocarcinoma (P>0.05). However, the expression of nm23 mRNA was correlated negatively to the lymph node metastasis of gastric and colorectal adenocarcinoma (r = -0.49, P<0.01; r = -4.93, P<0.01). The expression of CD44s in the tissues of gastric and colorectal adenocarcinoma was significantly different from that in the normal tissues adjacent to cancer (P<0.05; P<0.01). CD44v6 was expressed in the tissues of gastric and colorectal adenocarcinoma only, the expression of CD44v6 was significantly associated with the lymph node metastasis, invasion and pathological grade of the tumor (r = 0.47, P<0.01; r = 5.04, P<0.01). CD44s and CD44v6 were expressed in intraductal carcinoma of breast, the expression of CD44s and CD44v6 was significantly associated with lymph node metastases and invasion (P<0.01). However, neither of them was expressed in the normal breast tissue. In addition, the expression of CD44v6 was closely related to the degree of cell differentiation of intraductal carcinoma of breast (χ² = 5.68, P<0.05). The expressional level of nm23 mRNA was closely related to the degree of cell differentiation (P<0.05) and lymph node metastasis (P<0.01), but the expression of nm23 gene was not related to sex, age, and type of histological classification (P>0.05).

CONCLUSION: Patients with overexpression of CD44s and CD44v6 and low expression of nm23 mRNA have a higher lymph node metastatic rate and invasion. In addition, overexpression of CD44v6 is closely related to the degree of cell differentiation. Detection of the three genes is able to provide a reliable index to evaluate the invasion and metastasis of tumor cells.

The emerging role of CD44 in regulating skeletal micrometastasis

The hyaluronan (HA) receptor CD44 has a well documented role in tumour metastasis. This review focuses on the potential significance of CD44 expression and function in regulating the metastasis of both haematological malignancies and solid tumours to the bone. Specifically, the review will discuss the evidence that HA-CD44 interactions facilitate the arrest of circulating malignant cells upon the bone marrow endothelial cells and discuss data that suggests CD44 may orchestrate the ability of tumour cells to regulate the modification of the bone matrix and support its colonisation by malignant cells.

Clinicopathological associations of CD44 mRNA and protein expression in primary breast carcinomas

AIMS

The purpose of this study was to examine the occurrence of CD44 isoforms in breast carcinomas and their role in predicting clinical outcome.

METHODS AND RESULTS

Shock-frozen tumour tissues from 110 patients with breast carcinoma were examined by immunohistochemistry using antibodies directed against CD44s, v5, v6, v7 and v3-10. In addition, 80 of these tumours were available for quantitative real-time reverse transcriptase-polymerase chain reaction (RT-PCR) analysis of CD44s and CD44v6. Immunohistochemically, the positive tumours showed cytoplasmic and/or membranous staining with all antibodies. Staining results did not correlate with histological subtype, lymph node status, status of steroid receptors, tumour size or age. Neither was any correlation found for overall and disease-free survival. Quantitative real-time RT-PCR of CD44s and CD44v6, however, revealed that expression of CD44v6 mRNA was significantly associated with lower pathological grade (Pearson chi(2) test P = 0.009; linear-by-linear association P = 0.003). Linear-by-linear association between CD44s mRNA expression and lower pathological grade was also seen (P = 0.02). Survival analysis with the Kaplan-Meier method demonstrated that increased CD44s mRNA expression was significantly associated with both disease-free survival and overall survival (P = 0.0185 and P = 0.0344, respectively). A similar trend for CD44v6 mRNA expression was seen in these cases, but the difference was not significant.

CONCLUSIONS

Quantitative real-time RT-PCR revealed clinical correlations of CD44s and CD44v6 mRNA expression in breast carcinomas while immunohistochemistry for the protein expression of CD44s and other CD44 variants did not. This contradictory result merits further studies concerning the clinical impact of CD44 molecules in breast carcinomas.

Expression of sialyl-Tn antigen in breast cancer cells transfected with the human CMP-Neu5Ac: GalNAc alpha2,6-sialyltransferase (ST6GalNac I) cDNA

Sialyl-Tn antigen (STn) is a cancer associated carbohydrate antigen over-expressed in several cancers including breast cancer, and currently associated with more aggressive diseases and poor prognosis. However, the commonly used breast cancer cell lines (MDA-MB-231, T47-D and MCF7) do not express STn antigen. The key step in the biosynthesis of STn is the transfer of a sialic acid residue in alpha2,6-linkage to GalNAc alpha-O-Ser/Thr. This reaction is mainly catalyzed by a CMP-Neu5Ac GalNAc alpha2,6-sialyltransferase: ST6GalNAc I. In order to generate STn-positive breast cancer cells, we have cloned a cDNA encoding the full-length human ST6GalNAc I from HT-29-MTX cells. The stable transfection of MDA-MB-231 with an expression vector encoding ST6GalNAc I induces the expression of STn antigen at the cell surface. The expression of STn short cuts the initial O-glycosylation pattern of these cell lines, by competing with the Core-1 beta1,3-galactosyltransferase, the first enzyme involved in the elongation of O-glycan chains. Moreover, we show that STn expression is associated with morphological changes, decreased growth and increased migration of MDA-MB-231 cells.