Expression of a New Cellular Protein by Monocytoid B-Lymphocytes Differentiated from the Acute Lymphoblastic Leukemia Cell Line (REH)

Abstract

In an attempt to identify differentiation-related changes in cellular proteins, the common acute lymphoblastic leukemia (ALL) cell line, REH, was studied. REH cells were cultured in either the absence or presence of 12-0-tetradecanoylphorbol-13-acetate (TPA). Changes in surface phenotype were analyzed using monoclonal antibodies and flow cytometry. Cellular proteins were analyzed with two-dimensional polyacrylamide gel electrophoresis (2D-PAGE) of [(3)H]leucine and [(32)P]orthophosphate labeled cells. Immunophenotype and 2D-PAGE studies were replicated three times on untreated (control) and TPA-treated cells on day 5. Immunophenotypic analysis showed that TPA induced further differentiation of REH cells along the B-cell lineage as indicated by significant decrease in the expression of CD10, induction of CD11c and increase in the expression of CD22. 2D-PAGE of [(3)H]leucine but not the [(32)P]orthophosphate showed that TPA induced the expression of a unique protein. The apparent relative molecular mass (Mr) of the resolved protein was ~23 kd with a ~6.2 isoelectric point (PI). Based on the morphologic and phenotypic findings, our data suggest that the new protein (p23-6.2) and the quantitative changes in protein synthesis induced by TPA are differentiation-related. Our study also indicates that 2D-PAGE analysis is a sensitive and complementary tool to phenotypic markers in the study of differentiation of malignant B-cells.

Role of ubiquitin carboxyl terminal hydrolase in the differentiation of human acute lymphoblastic leukemia cell line, Reh

“…3a, b). The differentiation state of TPA-treated Reh cells was determined as a function of cell surface markers (CD10 and CD11c) and enzymatic activity (AcP and TdT) [22]. Such measurements are important in assessing the transition of the B cell along the differentiation pathway.…”

“…The effectiveness of the AODN obviously depends on its ability to penetrate the cell membrane. Little is known about the uptake process of the AODN but it most probably involves an endocytotic process [22] mediated by a receptor-like mechanism and fluid-phase endocytosis [5]. The cellular trafficking of AODN was studied using isotopically labeled AODN.…”