Co-expression of 9-O-acetylated sialoglycoproteins and their binding proteins on lymphoblasts of childhood acute lymphoblastic leukemia: an anti-apoptotic role.
Enhanced levels of 9-O-acetylated sialoglycoproteins (Neu5,9Ac(2)GPs) as disease-associated molecules was reported to act as signaling molecules for promoting survival of lymphoblasts in childhood acute lymphoblastic leukemia (ALL). Here, we searched for potential physiological ligands for Neu5,9Ac(2)GPs that could be involved in modulating the survival of lymphoblasts. Accordingly, we examined the presence of binding proteins for Neu5,9Ac(2)GPs on cell lines and primary cells of patients with B- and T-ALL, at presentation of the disease. Peripheral blood mononuclear cells from normal healthy donors and cells from myeloid leukemia patients were used for comparison. Neu5,9Ac(2)GPs-binding proteins (BPs) were specifically detected on the surface of both T- and B-ALL-lymphoblasts and ALL-cell lines along with the consistent presence of Neu5,9Ac(2)GPs. The Neu5,9Ac(2)GPs and BPs also co-localized on the cell surface and interacted specifically in vitro. Apoptosis of lymphoblasts, induced by serum starvation, was reversed in the presence of purified Neu5,9Ac(2)GPs due to possible engagement of BPs, and the anti-apoptotic role of this interaction was established. This is the first report of the presence of potential physiological ligands for disease-associated molecules like Neu5,9Ac(2)GPs, the interaction of which is able to trigger an anti-apoptotic signal conferring a survival advantage to leukemic cells in childhood ALL.
Mukherjee
Kankana
K
Infectious Diseases and Immunology Division, Indian Institute of Chemical Biology, 4, Raja S.C. Mullick Road, Kolkata 700032, India.
Chava
Anil K
AK
Bandyopadhyay
Suman
S
Mallick
Asish
A
Chandra
Sarmila
S
Mandal
Chitra
C
D000107:Acetylation; D000293:Adolescent; D000328:Adult; D017209:Apoptosis / Q000187:drug effects; D015153:Blotting, Western; D002453:Cell Cycle / Q000187:drug effects; D002460:Cell Line; D002648:Child; D002675:Child, Preschool; D005260:Female; D005434:Flow Cytometry; D006801:Humans; D007223:Infant; D008214:Lymphocytes / Q000378:metabolism*; D008297:Male; D018613:Microscopy, Confocal; D008875:Middle Aged; D054198:Precursor Cell Lymphoblastic Leukemia-Lymphoma / Q000378:metabolism*; D011485:Protein Binding; D012795:Sialoglycoproteins / Q000378:metabolism* / Q000494:pharmacology; D055815:Young Adult
D012795:Sialoglycoproteins