High CXCR3 on Leukemic Cells Distinguishes IgHV mut from IgHV unmut in Chronic Lymphocytic Leukemia: Evidence from CD5high and CD5low Clones

Role of the tumor microenvironment in CLL pathogenesis

Chronic lymphocytic leukemia (CLL) cells extensively interact with and depend on their surrounding tumor microenvironment (TME). The TME encompasses a heterogeneous array of cell types, soluble signals, and extracellular vesicles, which contribute significantly to CLL pathogenesis. CLL cells and the TME cooperatively generate a chronic inflammatory milieu, which reciprocally reprograms the TME and activates a signaling network within CLL cells, promoting their survival and proliferation. Additionally, the inflammatory milieu exerts chemotactic effects, attracting CLL cells and other immune cells to the lymphoid tissues. The intricate CLL-TME interactions also facilitate immune evasion and compromise leukemic cell surveillance. We also review recent advances that have shed light on additional aspects that are substantially influenced by the CLL-TME interplay.

Inhibition of protein kinase C isozymes causes immune profile alteration and possibly decreased tumorigenesis in bladder cancer

Protein kinase C (PRKC) isozymes activate many signaling pathways and promote tumorigenesis, which can be confirmed by masking the kinase activity. In the present study, the kinase activity of PRKC ε and ζ isozymes was masked by siRNA in bladder cancer, and the consequent gene profile was evaluated. Here, we show that the commonly dysregulated genes affected by both the isozymes were the chemokines (CXCL8 & CXCL10), adhesion molecules (ICAM1, SPP1, MMP3, VEGFA) and mutated isoform of TP53. As these same genes were upregulated in bladder cancer patients, the activity of the kinase in downregulating them is confirmed. These genes are associated with regulating the tumor microenvironment, proliferation and differentiation of cancer cells and poor prognosis. The effect of kinase masking in downregulating these genes in bladder cancer indicates the benefits PRKC inhibitors may have in managing these patients.

Immunophenotypic characterization of B1a lymphocytes in Cuban older adults

INTRODUCTION

B1a lymphocytes are characterized by having a high capacity for self-renewal and production of natural antibodies, in a T-independent manner. There are differences in both the number and composition of mature B lymphocytes throughout life, due to the phenomenon of immunosenescence.

OBJECTIVE

To characterize the immunophenotype of B1a lymphocytes in older Cuban adults with a simplified CD19CD20CD5 panel.

METHODS

A cross-sectional study was conducted in 30 institutionalized Cuban older adults. Characterization of CD19 + CD5+, CD20 + CD5+, and CD19 + CD20+ B lymphocytes in peripheral blood was performed by flow cytometry. For the reading and analysis of the biological samples, a flow cytometer, Beckman Coulter, Gallios, was used. A Microsoft Excel database was created with the information obtained. The sample was divided by sex and age. The data were processed using the statistical program GraphPadPrism version 6.00 using the percentage values and the median for the sample description.

RESULTS

The elderly aged 80 years and over showed a decrease in the absolute count of CD19 + CD20+ B lymphocytes, as well as in the percentage and absolute count of CD19 + CD5+ B lymphocytes. On the other hand, they presented higher absolute counts of CD20 + CD5+ lymphocytes in relation to those of the <80-year-old group. Women showed higher absolute counts of CD19 + CD5+, CD20 + CD5+, and CD19 + CD20+ B lymphocyte populations.

CONCLUSIONS

The immunophenotypic characterization of B1a lymphocytes in older Cuban adults is similar to that reported by other researchers. Both age and sex influence the absolute count of these cells, being higher in women under 80 years of age.

Towards a Better Characterisation of Leukemic Cells in Chronic Lymphocytic Leukaemia: Cell-Size Heterogeneity Reflects Their Activation Status and Migratory Abilities

Simple Summary

Chronic lymphocytic leukaemia (CLL) is a heterogeneous chronic disease characterised by the clonal expansion of mature CD19⁺CD23⁺CD5⁺ B-cells in blood, bone marrow and lymphoid tissue. Despite the CLL tumour cell population showing considerable heterogeneity in cell size, the functional characteristics of leukemic cells that differ in size have not been explored. The results of our study demonstrate that differences in CLL cell size reflect their activation state, polarisation and migratory capacity, with large CLL cells being more activated, polarised and motile than the small CLL cells present in the CLL cell pool. Our data provide evidence of the importance of cell-size heterogeneity within the CLL cell pool and the dynamics of cell-size changes for disease pathogenesis.

Abstract

Chronic lymphocytic leukaemia (CLL) is a genetically, morphologically and phenotypically heterogeneous chronic disease with clinical variability between patients. Whether the significant heterogeneity of cell size within the CLL population contributes to the heterogeneous features of this disease has not been investigated. The present study aimed to characterise the phenotypic and functional properties of two subpopulations of typical CLL cells that differ in cell size: small (s-CLL) and large (l-CLL) CLL cells delineated by forward scatter cytometry. The s-CLL cells were characterised by the CD5^lowCXCR4^hi phenotype, while the l-CLL cells were characterised by the CD5^hiCXCR4^dim phenotype and indicated a higher expression of CXCR3, CD20, CD38 and HLA-DR. The l-CLL cells displayed higher migration activity towards CXCL12, a tendency towards a higher proliferation rate and an increased capacity to produce IgM in the presence of CpG compared with s-CLL cells. When stimulated with CpG and CXCL12, l-CLL cells were characterised by a higher polarisation phenotype and motility than s-CLL cells. Our study revealed that the differences in CLL cell size reflected their activation status, polarisation and migratory abilities. Our data provide evidence of the importance of cell-size heterogeneity within a CLL pool and the dynamics of cell-size changes for disease pathogenesis, thus deserving further investigation.

Chemokines orchestrate tumor cells and the microenvironment to achieve metastatic heterogeneity

Chemokines, a subfamily of the cell cytokines, are low molecular weight proteins known to induce chemotaxis in leukocytes in response to inflammatory and pathogenic signals. A plethora of literature demonstrates that chemokines and their receptors regulate tumor progression and metastasis. With these diverse functionalities, chemokines act as a fundamental link between the tumor cells and their microenvironment. Recent studies demonstrate that the biology of chemokines and their receptor in metastasis is complex as numerous chemokines are involved in regulating site-specific tumor growth and metastasis. Successful treatment of disseminated cancer is a significant challenge. The most crucial problem for treating metastatic cancer is developing therapy regimes capable of overcoming heterogeneity problems within primary tumors and among metastases and within metastases (intralesional). This heterogeneity of malignant tumor cells can be related to metastatic potential, response to chemotherapy or specific immunotherapy, and many other factors. In this review, we have emphasized the role of chemokines in the process of metastasis and metastatic heterogeneity. Individual chemokines may not express the full potential to address metastatic heterogeneity, but chemokine networks need exploration. Understanding the interplay between chemokine-chemokine receptor networks between the tumor cells and their microenvironment is a novel approach to overcome the problem of metastatic heterogeneity. Recent advances in the understanding of chemokine networks pave the way for developing a potential targeted therapeutic strategy to treat metastatic cancer.