HS1 protein is differentially expressed in chronic lymphocytic leukemia patient subsets with good or poor prognoses.
We used a proteomic approach for identifying molecules involved in the pathogenesis of chronic lymphocytic leukemia (CLL). We investigated 14 patients who were completely concordant for IgV(H) mutational status (unmutated vs. mutated), CD38 expression (positive vs. negative), and clinical behavior (progressive vs. stable); these patients were characterized as having either poor or good prognoses. The 2 patient subsets differed in the expression of hematopoietic lineage cell-specific protein 1 (HS1). In patients with poor prognoses, most HS1 protein was constitutively phosphorylated, whereas only a fraction was phosphorylated in patients with good prognoses. This difference was investigated in a larger cohort of 26 unselected patients. The survival curve of all 40 patients analyzed revealed that patients with predominately phosphorylated HS1 experience a significantly shorter median survival time. As HS1 is a protein pivotal in the signal cascade triggered by B cell receptor (BCR) stimulation, we studied its pattern of expression following BCR engagement. Normal mature B cells stimulated by anti-IgM shifted the non- or less-phosphorylated form of HS1 toward the more phosphorylated form. Naive B cells showed both HS1 forms while memory B cells expressed mainly the phosphorylated fraction. These data indicate a central role for antigen stimulation in CLL and suggest a new therapeutic target for patients with aggressive disease.
Scielzo
Cristina
C
Department of Oncology, Università Vita e Salute-San Raffaele, Milan, Italy.
Ghia
Paolo
P
Conti
Antonio
A
Bachi
Angela
A
Guida
Giuseppe
G
Geuna
Massimo
M
Alessio
Massimo
M
Caligaris-Cappio
Federico
F
D036541:ADP-ribosyl Cyclase / Q000096:biosynthesis; D051997:ADP-ribosyl Cyclase 1; D048868:Adaptor Proteins, Signal Transducing; D000368:Aged; D000369:Aged, 80 and over; D015703:Antigens, CD / Q000096:biosynthesis; D001402:B-Lymphocytes / Q000378:metabolism*; D014408:Biomarkers, Tumor / Q000096:biosynthesis* / Q000235:genetics; D001798:Blood Proteins / Q000096:biosynthesis* / Q000235:genetics; D016022:Case-Control Studies; D005260:Female; D015973:Gene Expression Regulation, Leukemic / Q000235:genetics; D006801:Humans; D007143:Immunoglobulin Heavy Chains / Q000235:genetics / Q000378:metabolism; D007075:Immunoglobulin M / Q000096:biosynthesis / Q000235:genetics; D007135:Immunoglobulin Variable Region / Q000235:genetics / Q000378:metabolism; D015451:Leukemia, Lymphocytic, Chronic, B-Cell / Q000235:genetics / Q000378:metabolism*; D008297:Male; D008562:Membrane Glycoproteins; D008875:Middle Aged; D010766:Phosphorylation; D011379:Prognosis; D011499:Protein Processing, Post-Translational / Q000235:genetics; D011947:Receptors, Antigen, B-Cell / Q000096:biosynthesis / Q000235:genetics; D027041:Somatic Hypermutation, Immunoglobulin / Q000235:genetics
D048868:Adaptor Proteins, Signal Transducing; D015703:Antigens, CD; D014408:Biomarkers, Tumor; D001798:Blood Proteins; C061909:HCLS1 protein, human; D007143:Immunoglobulin Heavy Chains; D007075:Immunoglobulin M; D007135:Immunoglobulin Variable Region; D008562:Membrane Glycoproteins; D011947:Receptors, Antigen, B-Cell; D036541:ADP-ribosyl Cyclase; C498154:CD38 protein, human; D051997:ADP-ribosyl Cyclase 1