Expression of adhesion molecules LFA-1, ICAM-1, CD44, and L-selectin in childhood non-Hodgkin lymphomas

Differential B-Cell Receptor Signaling Requirement for Adhesion of Mantle Cell Lymphoma Cells to Stromal Cells

Interactions between lymphoma cells and stromal cells play a key role in promoting tumor survival and development of drug resistance. We identified differences in key signaling pathways between the JeKo-1 and REC-1 mantle cell lymphoma (MCL) cell lines, displaying different patterns of stromal cell adhesion and chemotaxis towards stroma-conditioned medium. The identified adhesion-regulated genes reciprocated important aspects of microenvironment-mediated gene modulation in MCL patients. Five-hundred and ninety genes were differently regulated between the cell lines upon adhesion to stromal cells, while 32 genes were similarly regulated in both cell lines. Regulation of B-cell Receptor (BCR) signature genes in adherent cells was specific for JeKo-1. Inhibition of BCR using siRNA or clinically approved inhibitors, Ibrutinib and Acalabrutinib, decreased adhesion of JeKo-1, but not REC-1 cells. Cell surface levels of chemokine receptor CXCR4 were higher in JeKo-1, facilitating migration and adhesion of JeKo-1 but not REC-1 cells. Surface levels of ICAM1 adhesion protein differ for REC-1 and JeKo-1. While ICAM1 played a positive role in adherence of both cell lines to stromal cells, S1PR1 had an inhibitory effect. Our results provide a model framework for further investigation of mechanistic differences in patient-response to new pathway-specific drugs.

Diagnostic and Prognostic Relevance of Bone Marrow Microenvironment Components in Non Hodgkin’s Lymphoma Cases Before and After Therapy

Objective:

To evaluate stromal cells of the bone marrow microenvironment (BMM) in bone marrow trephine biopsy (BMTB) specimens, with a focus on fibronectin, tumor necrosis factor- alpha (TNF-α) and L-selectin in Non-Hodgkin’s lymphoma (NHL) patients, before and after therapy.

Materials and Methods:

A total of 80 de novo NHL patients, 64 with B-cell lymphomas 80%, (follicular cell lymphoma (FCL) in 32, chronic lymphocytic leukemia/small lymphocytic lymphoma (CLL/SLL) in 12, and diffuse large cell lymphoma in 20) and 16 with T-cell lymphomas (20%) all diagnosed as T-Lymphoblastic lymphomas, were evaluated before and after therapy. For comparison, 25 age and sex matched BM donors, were included as a control group. BMTB material and BM aspirates were taken for morphological assessment of stromal cells, the plasma of these samples being examined for TNFα and L-selectin by ELISA, and fibronectin by radial immunodiffusion (RID).

Results:

BM stromal cells comprising reticular macrophages and fibroblasts were elevated in 53.3% of NHL cases at diagnosis, while BM fibronectin levels were decreased and BM TNFα and L-selectin were higher than in controls (p<0.05). In NHL cases, elevated values of BM TNFα and BM L-selectin were associated with signs of aggressive disease, including >1 extra nodal sites, detectable B symptoms, high grade, BM and CNS invasion, and a high International prognostic index (IPI) (p<0.05).

Conclusion:

BMM components, TNFα, L-selectin and fibronectin, in NHL can be useful in evaluating disease activity, extent and response to treatment and as prognostic markers according to the IPI.

The Differential Expression of Galectin-1 and Galectin-3 in Normal Lymphoid Tissue and Non-Hodgkin's and Hodgkin's Lymphomas

The WHO classification of lymphomas was established on the basis of clinical, morphological, immunohistochemical and genetic criteria. However, each entity displays its own spectrum of clinical aggressiveness. Treatment success varies widely and is not predictable. Since galectins are involved in oncogenesis and the physiology of immune cells, we investigated whether galectin-1 and galectin-3 immunohistochemical expression could differ in 25 normal lymphoid tissues, 42 non-Hodgkin's and 14 Hodgkin's lymphomas. Immunohistochemical galectin expression was submitted to semi-quantitative and quantitative (computer-assisted microscopy) evaluations. This study is completed by an analysis (by means of quantitative RT-PCR) of galectin-3 mRNA expression in 3 normal lymph nodes, 3 follicular lymphomas (FLs) and 3 diffuse large B-cell lymphomas (DLBCLs). The data show that in normal lymphoid tissue, lymphocytes do not express galectin-1 and rarely express galectin-3. In contrast, galectin-3 was expressed in 8 of the 16 DLBCL cases and in 1 of the 8 FL cases. Furthermore, galectin-3 mRNA was expressed 3-times more in the DLBCLs than in the FLs. While the blood vessel walls of the lymphomas expressed galectin-1, the vessel walls of normal lymphoid tissues did not. This expression of galectin-1 in blood vessel walls was correlated with vascular density. The present study thus shows that DLBCL can be distinguished from normal lymphoid tissue and other lymphomas on the basis of galectin-3 expression.

Flow cytometry in lymphoma diagnosis and prognosis: useful?

Flow cytometry has become an important tool in the diagnosis of mature lymphoid neoplasms and the determination of prognosis in selected cases. The advantages of flow cytometry are based largely on its ability to analyse, rapidly and simultaneously, multiple cell properties in a quantitative manner. Flow cytometric immunophenotyping is useful in diagnosing lymphoma under the WHO classification system, where lymphoid neoplasms are separated into distinct clinical entities based upon morphology, immunophenotype, genetic abnormalities and clinical features. Flow cytometry can quantify the expression of proteins associated with a good or poor prognosis, detect multidrug resistance, and measure cell proliferation, making it useful in measuring prognostic indicators in lymphoid neoplasia. The unique attributes of flow cytometry therefore make it a valuable technique in the diagnosis and classification of lymphomas as well as the assessment of prognostic markers in lymphoma patients.