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CXCL12-induced VLA-4 activation is impaired in trisomy 12 chronic lymphocytic leukemia cells: a role for CCL21.

Ganghammer S, Hutterer E, Hinterseer E, Brachtl G, Asslaber D, Krenn PW, Girbl T, Berghammer P, Geisberger R, Egle A, Zucchetto A, Kruschinski A, Gattei V, Chigaev A, Greil R, Hartmann TN - Oncotarget (2015)

Bottom Line: Here, we demonstrate that high CD49d expression in tri12 CLL is accompanied by decreased CXCR4 expression.Concordantly, in real-time kinetic analyses we found CCL21 but not CXCL12 being capable to induce inside-out VLA-4 conformational changes in this CLL subgroup.Our results provide novel insights into the peculiar clinico-biological behaviour of tri12 CLL and emphasize its specific chemokine and integrin utilization during pathophysiologically and therapeutically relevant interactions with the microenvironment.

View Article: PubMed Central - PubMed

Affiliation: Laboratory for Immunological and Molecular Cancer Research, 3rd Medical Department with Hematology, Medical Oncology, Hemostaseology, Infectious Diseases and Rheumatology, Oncologic Center, Paracelsus Medical University Salzburg, Austria.

ABSTRACT
Homing to distinct lymphoid organs enables chronic lymphocytic leukemia (CLL) cells to receive pro-survival and proliferative signals. Cytogenetic aberrations can significantly affect CLL cell compartmentalization. Trisomy 12 (tri12) defines a CLL subgroup with specific clinical features and increased levels of the negative prognostic marker CD49d, the α4-subunit of the integrin VLA-4, which is a key regulator of CLL cell homing to bone marrow (BM). Chemokine-induced inside-out VLA-4 activation, particularly via the CXCL12-CXCR4 axis, increases the arrest of various cell types on VCAM-1 presenting endothelium. Here, we demonstrate that high CD49d expression in tri12 CLL is accompanied by decreased CXCR4 expression. Dissecting functional consequences of these alterations, we observed that tri12 CLL cell homing to murine BM is not affected by CXCR4-CXCL12 blockage using AMD3100 or olaptesed pegol/NOX-A12. In line, CCL21-CCR7 rather than CXCL12-CXCR4 interactions triggered VLA-4-mediated arrests of tri12 CLL cells to VCAM-1 under blood flow conditions. Concordantly, in real-time kinetic analyses we found CCL21 but not CXCL12 being capable to induce inside-out VLA-4 conformational changes in this CLL subgroup. Our results provide novel insights into the peculiar clinico-biological behaviour of tri12 CLL and emphasize its specific chemokine and integrin utilization during pathophysiologically and therapeutically relevant interactions with the microenvironment.

No MeSH data available.


Related in: MedlinePlus

Chemotaxis of tri12 CLL towards CXCL12 is intact despite lower CXCR4 expression(A) Boyden chamber migration assays of no tri12 (n = 17) and tri12 (n = 7) CLL cells towards CXCL12. Each experiment has been performed in duplicates; columns show the mean ± SD of all experiments performed. (B) Flow-cytometric comparison of CXCR4 surface expression of no tri12 and tri12 CLL samples used in (A).
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Figure 4: Chemotaxis of tri12 CLL towards CXCL12 is intact despite lower CXCR4 expression(A) Boyden chamber migration assays of no tri12 (n = 17) and tri12 (n = 7) CLL cells towards CXCL12. Each experiment has been performed in duplicates; columns show the mean ± SD of all experiments performed. (B) Flow-cytometric comparison of CXCR4 surface expression of no tri12 and tri12 CLL samples used in (A).

Mentions: Collectively, our observations could either point to a general CXCR4 dysfunction or to a specific alteration in the CXCL12-induced VLA-4 activation cascade in tri12 CLL cells. We therefore tested the ability of no tri12 versus tri12 CLL cells to migrate towards CXCL12 in chemotaxis assays. Notably, under these shear free conditions, tri12 CLL cells tended to migrate towards CXCL12 even at higher rates than no tri12 CLL cells (Figure 4A) despite expressing lower CXCR4 surface levels (Figure 4B). Chemotaxis was markedly reduced by AMD3100, ola-PEG and PTX in both subgroups to a similar extent (Supplemental Figure 3). These findings suggest a fully functional CXCR4 receptor and an integrin-independent random motility that is not compromised in tri12 CLL cells.


CXCL12-induced VLA-4 activation is impaired in trisomy 12 chronic lymphocytic leukemia cells: a role for CCL21.

Ganghammer S, Hutterer E, Hinterseer E, Brachtl G, Asslaber D, Krenn PW, Girbl T, Berghammer P, Geisberger R, Egle A, Zucchetto A, Kruschinski A, Gattei V, Chigaev A, Greil R, Hartmann TN - Oncotarget (2015)

Chemotaxis of tri12 CLL towards CXCL12 is intact despite lower CXCR4 expression(A) Boyden chamber migration assays of no tri12 (n = 17) and tri12 (n = 7) CLL cells towards CXCL12. Each experiment has been performed in duplicates; columns show the mean ± SD of all experiments performed. (B) Flow-cytometric comparison of CXCR4 surface expression of no tri12 and tri12 CLL samples used in (A).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4494922&req=5

Figure 4: Chemotaxis of tri12 CLL towards CXCL12 is intact despite lower CXCR4 expression(A) Boyden chamber migration assays of no tri12 (n = 17) and tri12 (n = 7) CLL cells towards CXCL12. Each experiment has been performed in duplicates; columns show the mean ± SD of all experiments performed. (B) Flow-cytometric comparison of CXCR4 surface expression of no tri12 and tri12 CLL samples used in (A).
Mentions: Collectively, our observations could either point to a general CXCR4 dysfunction or to a specific alteration in the CXCL12-induced VLA-4 activation cascade in tri12 CLL cells. We therefore tested the ability of no tri12 versus tri12 CLL cells to migrate towards CXCL12 in chemotaxis assays. Notably, under these shear free conditions, tri12 CLL cells tended to migrate towards CXCL12 even at higher rates than no tri12 CLL cells (Figure 4A) despite expressing lower CXCR4 surface levels (Figure 4B). Chemotaxis was markedly reduced by AMD3100, ola-PEG and PTX in both subgroups to a similar extent (Supplemental Figure 3). These findings suggest a fully functional CXCR4 receptor and an integrin-independent random motility that is not compromised in tri12 CLL cells.

Bottom Line: Here, we demonstrate that high CD49d expression in tri12 CLL is accompanied by decreased CXCR4 expression.Concordantly, in real-time kinetic analyses we found CCL21 but not CXCL12 being capable to induce inside-out VLA-4 conformational changes in this CLL subgroup.Our results provide novel insights into the peculiar clinico-biological behaviour of tri12 CLL and emphasize its specific chemokine and integrin utilization during pathophysiologically and therapeutically relevant interactions with the microenvironment.

View Article: PubMed Central - PubMed

Affiliation: Laboratory for Immunological and Molecular Cancer Research, 3rd Medical Department with Hematology, Medical Oncology, Hemostaseology, Infectious Diseases and Rheumatology, Oncologic Center, Paracelsus Medical University Salzburg, Austria.

ABSTRACT
Homing to distinct lymphoid organs enables chronic lymphocytic leukemia (CLL) cells to receive pro-survival and proliferative signals. Cytogenetic aberrations can significantly affect CLL cell compartmentalization. Trisomy 12 (tri12) defines a CLL subgroup with specific clinical features and increased levels of the negative prognostic marker CD49d, the α4-subunit of the integrin VLA-4, which is a key regulator of CLL cell homing to bone marrow (BM). Chemokine-induced inside-out VLA-4 activation, particularly via the CXCL12-CXCR4 axis, increases the arrest of various cell types on VCAM-1 presenting endothelium. Here, we demonstrate that high CD49d expression in tri12 CLL is accompanied by decreased CXCR4 expression. Dissecting functional consequences of these alterations, we observed that tri12 CLL cell homing to murine BM is not affected by CXCR4-CXCL12 blockage using AMD3100 or olaptesed pegol/NOX-A12. In line, CCL21-CCR7 rather than CXCL12-CXCR4 interactions triggered VLA-4-mediated arrests of tri12 CLL cells to VCAM-1 under blood flow conditions. Concordantly, in real-time kinetic analyses we found CCL21 but not CXCL12 being capable to induce inside-out VLA-4 conformational changes in this CLL subgroup. Our results provide novel insights into the peculiar clinico-biological behaviour of tri12 CLL and emphasize its specific chemokine and integrin utilization during pathophysiologically and therapeutically relevant interactions with the microenvironment.

No MeSH data available.


Related in: MedlinePlus