Catherine M. Listinsky

Cell surface associated alpha-L-fucose moieties modulate human breast cancer neoplastic progression.

Glycosylation drives critical processes important for mammalian cell–cell and cell–matrix interactions. Alpha-l-fucose (α-l-f) is a key monosaccharide component of oligosaccharides that has been found to be overexpressed during tumor progression. Modification of cell surface fucosylation, we hypothesized, alters tumor cell phenotype and function at the end of the neoplastic progression cascade including tumor invasion. Alpha-l-fucosidase (α-l-fase) is a glycosidase that specifically removes (α-l-f) from oligosaccharide sites. We first verified the effectiveness of the α-l-fase to specifically decrease the level of α-l-f on the cell surface of several human breast cancer cell lines and also examined the recovery time for these cells to repopulate their surfaces. To investigate the potential effect of defucosylation on tumor functions, we studied the proliferation, and invasion in vitro of human breast cancer MDA-MB-231 cells as the representative cell model. We further examined several fucose-associated molecules previously shown to be involved in tumor progression, including CD44 and CD15 (Lewis X antigen). We found that α-l-fase pretreatment significantly decreased the invasive capability of breast cancer cells. Deoxyfuconojirimycin (DFJ), a specific α-l-fase inhibitor, reversed this effect. After fucosidase treatment, the level of both CD15 and CD44 were found to be reduced as measured by flow cytometry. α-l-fase treatment, further, did not affect tumor cell proliferation in vitro under identical experimental conditions. Gelatin zymography of conditioned media from tumor cells treated with α-l-fase demonstrated no change in MMP-2 activity while MMP-9 was significantly reduced. In summary, fucose containing glycans were found widely distributed on the cell surface of breast cancer cells and could be effectively removed by α-l-fase treatment. This decreased fucosylation, in turn, was seen to impair the interaction between tumor cells and extracellular matrices, and thus affected key cell functions modulating tumor invasion. Further elucidation of the molecular pathways involved in the inhibition of tumor cell invasion may suggest a rationale for the use of glycobiologic therapeutics to deter tumor progression.

Expression of HGAL in primary cutaneous large B-cell lymphomas: evidence for germinal center derivation of primary cutaneous follicular lymphoma

The classification of primary cutaneous large B-cell lymphoma (PCLBCL) is based on standard morphology, immunohistochemistry, and clinical presentation. There are two major subtypes in the current WHO–EORTC classification: follicle center lymphoma and diffuse large B-cell lymphoma, leg-type (DLBCL-LT). The goals of this study were to examine a series of DLBCLs to determine (1) whether the immunohistochemical paradigm of germinal center B-cell and non-germinal center B-cell types of systemic DLBCL could be applied to PCLBCL; (2) whether application of the newly described germinal center B-cell marker, human germinal center-associated lymphoma (HGAL) also discriminates between these types as a further support for germinal center B-cell origin for primary cutaneous center lymphoma; and (3) whether any of these biologic markers were of prognostic significance. To this end, 32 cases of diffuse PCLBCL (22 primary cutaneous follicular center lymphomas and 10 DLBCL-LT) were classified based on the WHO–EORTC criteria and studied for expression of CD20, BCL2, BCL6, CD10, MUM-1, and HGAL by immunohistochemistry. Results were correlated with clinical features. HGAL and BCL6 expression and germinal center B-cell phenotype were associated with primary cutaneous follicular center lymphoma. The combination of HGAL and BCL6 positivity had the highest sensitivity (88%) and specificity (100%) for predicting subtype compared to either marker alone. Both HGAL and BCL6 were associated with the germinal center B-cell phenotype. The correlation of HGAL expression with the germinal center B-cell phenotype demonstrates the role of this marker in the classification of cutaneous large B-cell lymphomas. BCL6 expression was the only immunohistochemical marker associated with overall survival. Characterizing PCLBCLs with markers of B-cell maturation stage is a useful framework for studying, classifying, and clinically stratifying these lymphomas.

Glycoengineering in cancer therapeutics: a review with fucose-depleted trastuzumab as the model.

Experimentally modified trastuzumab antibodies show increased cytotoxic potency when used with human effector cells against HER2-overexpressing human breast cancer cells in vitro and ex vivo. Furthermore, the superior efficacy of ‘glycoengineered’ trastuzumab has been confirmed in vivo utilizing a preclinical xenograft model of human HER2-amplified, trastuzumab-resistant human breast cancer. The increased cytotoxic potency coupled with other improvements are achieved by a seemingly modest change in trastuzumab’s structure, that is, depletion of two &agr;-L-fucose residues from trastuzumab’s heavy chains. Fucose-free trastuzumab binds with much greater affinity to human natural killer cells. This improved binding induces much greater antibody-dependent cellular cytotoxicity against HER2-overexpressing cells. The pharmaceutical industry has recognized the advantages of fucose-free therapeutic antibodies and has developed technologies that aim to mass produce such antibodies for human use. Here, we summarize data from multiple academic and pharmaceutical laboratories highlighting fucose depletion of antibodies as a key strategy of glycoengineering in cancer therapeutics. We use fucose-depleted trastuzumab as a model to show the advantages of this new class of anticancer agents. We predict that these advantages will translate clinically into improved therapeutics for many patients including those with HER2-overexpressing neoplasms.

Aggressive B-cell lymphomas.

The aggressive B-cell lymphomas are surprisingly heterogeneous in morphologic and architectural features, despite their common cell lineage. There are, in addition, a variety of differences among these entities that have no morphologic correlates. These disorders were spotlighted in the XI Workshop of the European Association of Hematopathology in May 2002 in Siena, Italy, and reviewed in the symposium of the American Society for Hematopathology in March 2003 at the Annual Meeting of the US-Canadian Academy of Pathology.1, 2, 3 Like the symposium, this presentation is derived from material presented at the XI European Workshop.Our intention is to provide a practical,illustrated update on the aggressive B-cell lymphomas for general pathologists in practice.