Towards a Better Characterisation of Leukemic Cells in Chronic Lymphocytic Leukaemia: Cell-Size Heterogeneity Reflects Their Activation Status and Migratory Abilities
by
, , ,
Gayane Manukyan
1,2, 
Zuzana Mikulkova
1,
Peter Turcsanyi
3,
Jakub Savara
1,4,
Markéta Trajerová
1,
Zuzana Kubova
3,
Tomas Papajik
3 and
Eva Kriegova
1,* 1
Department of Immunology, Faculty of Medicine and Dentistry, Palacký University and University Hospital, 77900 Olomouc, Czech Republic
2
Laboratory of Molecular and Cellular Immunology, Institute of Molecular Biology NAS RA, Yerevan 0014, Armenia
3
Department of Hematology-Oncology, Faculty of Medicine and Dentistry, Palacký University and University Hospital, 77900 Olomouc, Czech Republic
4
Department of Computer Science, Faculty of Electrical Engineering and Computer Science, VSB-Technical University of Ostrava, 70800 Ostrava, Czech Republic
*
Author to whom correspondence should be addressed.
Cancers 2021, 13(19), 4922; https://doi.org/10.3390/cancers13194922
Submission received: 17 August 2021
/
Revised: 21 September 2021
/
Accepted: 27 September 2021
/
Published: 30 September 2021
(This article belongs to the Special Issue Tumor Heterogeneity: Recent Trends and Current Issues)
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 CD5lowCXCR4hi phenotype, while the l-CLL cells were characterised by the CD5hiCXCR4dim 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.
