Aberrantly expressed CEACAM6 is involved in the signaling leading to apoptosis of acute lymphoblastic leukemia cells.
OBJECTIVE
The aberrant expression of myeloid antigens on acute lymphoblastic leukemia (ALL) cells is a well-documented phenomenon. So far, there have been no reports of a functional consequence of this aberrant expression. The granulocytic marker carcinoembryonic antigen-related cell adhesion molecule 6 (CEACAM6, CD66c) is a GPI-anchored molecule that is reported to be the most frequently aberrantly expressed myeloid marker in ALL with a strong correlation with genotype.


METHODS
We mimicked CEACAM6 signaling in ALL cells by cross-linking with anti-CEACAM6 antibody. Next, we measured a response to CEACAM6 signaling by integrin subunits expression, integrin ligand binding, phosphorylation of extracellular signal-regulated kinase 1/2 (Erk1/2), Akt, and p38 mitogen-activated protein kinase (MAPK) and apoptosis by flow cytometry.


RESULTS
Following CEACAM6 cross-linking in ALL cells, we detected Erk1/2, Akt, and p38 MAPK phosphorylation and integrin upregulation, as well as enhanced binding of integrin ligands (vascular cell adhesion molecule-1 [VCAM-1] and intercellular cell adhesion molecule-1 [ICAM-1]). However, CEACAM6 signaling resulted in an increase in apoptosis, unlike other GPI-anchored molecules, such as CD24.


CONCLUSIONS
The present study is the first to demonstrate the functional consequences of CEACAM6 cross-linking in B-cell precursor ALL cells.
Kanderová
Veronika
V
Department of Pediatric Hematology and Oncology, Charles University Prague, University Hospital Motol, Czech Republic.
Hrusák
Ondrej
O
Kalina
Tomás
T
D000912:Antibodies, Neoplasm / Q000276:immunology / Q000494:pharmacology; D015703:Antigens, CD / Q000276:immunology / Q000378:metabolism*; D000951:Antigens, Neoplasm / Q000276:immunology / Q000378:metabolism*; D017209:Apoptosis; D015815:Cell Adhesion Molecules / Q000037:antagonists & inhibitors / Q000276:immunology / Q000378:metabolism*; D045744:Cell Line, Tumor; D058851:GPI-Linked Proteins; D015973:Gene Expression Regulation, Leukemic; D006801:Humans; D007152:Immunologic Capping; D016023:Integrins / Q000276:immunology / Q000378:metabolism; D018799:Intercellular Adhesion Molecule-1 / Q000276:immunology / Q000378:metabolism; D020935:MAP Kinase Signaling System; D048052:Mitogen-Activated Protein Kinase 3 / Q000276:immunology / Q000378:metabolism; D051058:Oncogene Protein v-akt / Q000276:immunology / Q000378:metabolism; D010766:Phosphorylation / Q000187:drug effects / Q000276:immunology; D015452:Precursor B-Cell Lymphoblastic Leukemia-Lymphoma / Q000276:immunology / Q000378:metabolism*; D048051:p38 Mitogen-Activated Protein Kinases / Q000276:immunology / Q000378:metabolism
D000912:Antibodies, Neoplasm; D015703:Antigens, CD; D000951:Antigens, Neoplasm; C504117:CEACAM6 protein, human; D015815:Cell Adhesion Molecules; D058851:GPI-Linked Proteins; D016023:Integrins; D018799:Intercellular Adhesion Molecule-1; D051058:Oncogene Protein v-akt; D048052:Mitogen-Activated Protein Kinase 3; D048051:p38 Mitogen-Activated Protein Kinases