CD44 is exposed to the extracellular matrix at invasive sites in basal cell carcinomas

Transcriptome Analysis of Diffuse Large B-Cell Lymphoma Cells Inducibly Expressing MyD88 L265P Mutation Identifies Upregulated CD44, LGALS3, NFKBIZ, and BATF as Downstream Targets of Oncogenic NF-κB Signaling

During innate immune responses, myeloid differentiation primary response 88 (MyD88) functions as a critical signaling adaptor protein integrating stimuli from toll-like receptors (TLR) and the interleukin-1 receptor (IL-1R) family and translates them into specific cellular outcomes. In B cells, somatic mutations in MyD88 trigger oncogenic NF-κB signaling independent of receptor stimulation, which leads to the development of B-cell malignancies. However, the exact molecular mechanisms and downstream signaling targets remain unresolved. We established an inducible system to introduce MyD88 to lymphoma cell lines and performed transcriptomic analysis (RNA-seq) to identify genes differentially expressed by MyD88 bearing the L265P oncogenic mutation. We show that MyD88L265P activates NF-κB signaling and upregulates genes that might contribute to lymphomagenesis, including CD44, LGALS3 (coding Galectin-3), NFKBIZ (coding IkBƺ), and BATF. Moreover, we demonstrate that CD44 can serve as a marker of the activated B-cell (ABC) subtype of diffuse large B-cell lymphoma (DLBCL) and that CD44 expression is correlated with overall survival in DLBCL patients. Our results shed new light on the downstream outcomes of MyD88L265P oncogenic signaling that might be involved in cellular transformation and provide novel therapeutical targets.

Cancer stem-like cells in adenoid cystic carcinoma of salivary glands: relationship with morphogenesis of histological variants

BACKGROUND

Adenoid cystic carcinoma (AdCC) is a common malignant salivary gland tumor. AdCC is histologically characterized as having cribriform, tubular and solid patterns, and production of excess extracellular matrix (ECM). Cancer stem cells (CSCs) are defined cells within a tumor that possess the capacity to self-renew and to induce the heterogeneous lineages of cancer cells that comprise the tumor.

METHODS

To examine the morphogenetic relationship between CSCs and the growth patterns in AdCC, we employed formalin-fixed and paraffin-embedded 26 cases of AdCC and immunohistochemically clarified the distribution of CSCs using CD133 and CD44 antibodies.

RESULTS

CD133- or CD44-positive cancer stem (CS)-like cells were scattered in the pseudocyst-lining area of cribriform patterns having a Swiss cheese-like appearance. However, based on the further overproduction of ECM, CS-like cells accumulate in thin epithelial cords or trabecular arrangements. These CS-like cell aggregations are considered to form two cell-layered tubular patterns. Moreover, proliferation of outer cells in tubular patterns leads to cribriform patterns or solid patterns in the presence of excess ECM production or a lack of ECM overproduction, respectively. CS-like cells in AdCC were frequently located at the border areas adjacent to ECM, with exception of some cribriform and solid variants.

CONCLUSION

It is suggested that CSCs included in CD133- or CD44-positive cells play an important role in morphogenesis of salivary AdCC, especially in transition among the histological growth patterns. ECM is well known as a component of the CSC microenvironment, and ECM may regulate morphogenesis of AdCC through the stimulation of CSCs.

Nodular basal cell carcinoma is associated with increased hyaluronan homeostasis

BACKGROUND

Basal cell carcinoma (BCC) is one of the most frequent forms of malignancy in humans. Although BCC is a tumour of low degree of malignancy, if left untreated, it can be locally aggressive, eat away at tissues and cause ulceration. Nodular is the most common subtype of BCC (>50%). Although apparently non-invasive, micronodular, a certain subgroup of nodular, is likely to recur. Glycosaminoglycans (GAGs), such as hyaluronic acid (HA), are extracellular matrix molecules of high importance in malignant transformation, metastasis and other complex remodelling processes.

OBJECTIVES

To investigate the expression of GAGs and their metabolizing enzymes in nodular BCC, when compared with adjacent healthy human skin tissue specimens.

METHODS

Total GAGs were isolated and purified from nodular BCC and normal adjacent human skin tissue specimens. GAGs were subsequently fractionated by electrophoresis on cellulose acetate membranes and characterized using specific GAG-degrading enzymes. The content of HA in total GAGs was measured using ELISA and the expression of HA synthases (HAS), hyaluronidases (HYAL) and HA receptors (CD44 and receptor hyaluronic acid-mediated motility (RHAMM) was assessed using RT-PCR.

RESULTS

Nodular BCC is associated with increased levels of HA concomitant with upregulation of gene expression of HAS3, HYAL3 and RHAMM, when compared with normal adjacent skin.

CONCLUSION

These results indicate that HA homeostasis in nodular BCC shows distinct features which may be helpful in understanding the complex behaviour of nodular subtype of BCC, thus eventually leading to new treatment strategies.

Directional sensing of a phorbol ester gradient requires CD44 and is regulated by CD44 phosphorylation

Cancer progression is associated with enhanced directional cell migration, both of the tumour cells invading into the stroma and stromal cells infiltrating the tumour site. In cell-based assays to study directional cell migration, phorbol esters are frequently used as a chemotactic agent. However, the molecular mechanism by which these activators of protein kinase C (PKC) result in the establishment of a polarized migratory phenotype is not known. Here we show that CD44 expression is essential for chemotaxis towards a phorbol ester gradient. In an investigation of CD44 phosphorylation kinetics in resting and stimulated cells, Ser316 was identified as a novel site of phosphorylation following activation of PKC. PKC does not phosphorylate Ser316 directly, but rather mediates the activation of downstream Ser316 kinase(s). In transfection studies, a phosphorylation-deficient Ser316 mutant was shown to act in a dominant-negative fashion to impair chemotaxis mediated by endogenous CD44 in response to a phorbol ester gradient. Importantly, this mutation had no effect on random cell motility or the ability of cells to migrate directionally towards a cocktail of chemoattractants. These studies demonstrate that CD44 functions to provide directional cues to migrating cells without affecting the motility apparatus.

Microarray profiles of human basal cell carcinoma: Insights into tumor growth and behavior

PURPOSE

Basal cell carcinoma (BCC) is the most common human neoplasm. Much interest lies in determining the genetic basis of BCC to explain the unique locally invasive phenotype and infrequent metastatic behavior of these skin tumors.

OBJECTIVE

We sought to examine a gene expression profile for BCC to elucidate new molecules responsible for its unique growth characteristics.

METHODS

We analyzed gene expression patterns of 50 BCC tumors using spotted cDNA microarrays of 1718 characterized human genes related to cancer and immunity. This is the largest and most comprehensive gene expression study ever performed for BCC. Nodular and sclerosing histological subtypes of BCC were examined and compared to normal control skin. After statistical filtering, 374 significantly dysregulated genes were sorted by hierarchical clustering to determine trends of gene expression and similarities between patient gene expression profiles.

RESULTS

A total of 165 upregulated genes and 115 downregulated genes were identified. These covered a range of categories, including extracellular matrix, cell junctions, motility, metastasis, oncogenes, tumor suppressors, DNA repair, cell cycle, immune regulation and angiogenesis. Clusters of genes were either commonly dysregulated across the 50 patient sample, or selectively affected in subsets of tumors. Histological subtypes were not distinguishable by hierarchical clustering. Many of the genes elucidated, including collagen type IV subunits and other novel candidates, possess functions related to extracellular matrix remodeling and metastasis.

CONCLUSION

These results suggest a gene profile which may explain the invasive growth yet rarely metastatic behavior of BCC. The genes identified may also be potential targets for therapeutics aimed at further controlling invasiveness and local destruction of BCC.

Modulation of ezrin and E-cadherin expression by IL-1beta and TGF-beta1 in human trophoblasts

OBJECTIVES

The present study examines the effects of IL-1beta and TGF-beta1 in modulation of ezrin, E-cadherin, CD44 and beta-catenin expression in human trophoblast cells which may lead to their altered cytoskeleton dynamics during cell-to-cell and cell-to-matrix interactions.

METHODS

Trophoblast (extravillous and villous) cells isolated and purified from early and term placentae and human choriocarcinoma cell line JEG-3 used in this study were challenged with either IL-1beta or TGF-beta1 (10 ng/ml) for 12 h following which RT-PCR was performed for ezrin, E-cadherin, CD44 and beta-catenin. Immunolocalization of these proteins was carried out in the chorionic villi as well as in the cultured cells stimulated by the cytokines. Western Blot was also performed to study the regulation of ezrin and E-cadherin in primary extravillous, villous and term trophoblast by these cytokines. Scanning electron microscopy (SEM) and Matrigel Invasion Assay was used to study the effect of these cytokines on cellular morphology and invasion.

RESULTS

IL-1beta induced a down regulation in the expression of ezrin, E-cadherin and beta-catenin while upregulation of CD44 message in both primary trophoblast and JEG-3 cells. On the contrary, TGF-beta1 exhibited just an opposite effect, i.e. up regulation of ezrin, E-cadherin, beta-catenin, and down regulation of CD44. These observations were further corroborated with the immunolocalization findings of the above proteins in first trimester and term villous tissue, the former having predominance of IL-1beta and the latter of TGF-beta1 [Am. J. Reprod. Immunol. 48 (2002) 210]. Cellular morphology as observed through SEM revealed an enhanced cell-to-matrix adhesion with poor cell-cell interaction following IL-1beta challenge and a strong intercellular adhesion with weak cell-to-matrix interaction in presence of TGF-beta1. Crystal violet staining and Matrigel invasion revealed a higher invasion index following IL-1beta challenge and a low invasion index following TGF-beta1 challenge.

CONCLUSION

IL-1beta mediated increased cell-to-matrix interaction with reduced cell-to-cell adhesion along with reduced ezrin and E-cadherin expression is associated with enhanced invasiveness while TGF-beta1 mediated up regulation of cell-to-cell adhesion with reduced cell-to-matrix interaction along with an increased ezrin and E-cadherin expression, is associated with reduced invasiveness, along with an altered cellular morphology. These facts therefore indicate the possible role of the two cytokines during cell motility and invasion through alteration of cell-matrix and cell-cell interaction.

The stromal reaction in basal cell carcinomas. A prerequisite for tumour progression and treatment strategy

Specimens of basal cell carcinomas collected from 28 patients were classified into three groups: superficial, nodular, and infiltrative, according to their microarchitecture. The specimens were then subjected to histological characterization by means of a biotinylated hyaluronan-binding probe (HABP). By using Ki-67 and PCNA the proliferative activity of the BCC tumours was evaluated with immunohistological techniques. In superficial BCC the tumour islands displayed moderate hyaluronan (HA) staining. Feeble proliferation, denoted by modest mitotic activity and weak Ki-67 and PCNA immunoreactivity, occurred within the tumour islands. The surrounding connective tissue resembled normal skin, and no differentiated tumour stroma was observed. In nodular BCC, the HA staining of the tumour strands was weak to moderate, denoting increased proliferative activity. The differentiated surrounding tumour stroma stained strongly for HA. Tumour islands of infiltrative BCC stained weakly to moderately to HA and evidenced intense proliferation. The intensely HA-stained tumour stroma ended abruptly and the adjacent areas were almost devoid of HA. This study showed that the proliferative activity of BCC cells is associated with increased expression of HA in the tumour stroma. Modification of tumour-associated connective tissue indicates a close relationship between the tumour cells and the adjacent matrix. In particular, in infiltrative BCC, such alterations include degeneration and possible modification and remodelling of the surrounding extracellular matrix. These processes involving areas of probable importance for tumour progression, should be considered when deciding the extent of intended surgical resection.