Notch receptor and ligands

• Receptor isoforms: Notch 1-4• Ligands: jagged 1, jagged 2, delta1, delt

a2, delta 3, delta 4• Microenviroment of bone marrow stroma

Materials and methods• Cell culture:

• Myeloma cell line: RPMI-8226, OPM-2, LP-1, NCI-H929, U266, • Hodgkin cell ine:KM-H2• Burkitt lymphoma cell line: BJAB• HtTA-jag10 cell (under tetracycline control)

• Isolation and preparation of CD19+ B cells and CD19 low CD 38 high plasma cells

• Enrichment of primary multiple myeloma cells• Immunohistochemistry• Immunoblotting• RT-PCR analysis• Proliferation assay

Materials and methods

• Cell cultures, vectors and drugs• Gene transfer• Interaction between myeloma cells and strom

a; detection of apoptosis• Cell proliferation and cell cycle distribution• Elctromobility shift assay• Luciferase assay• Quantitative PCR of the HES-1 gene• Western blotting

Results

• Notch-1 activated in hematologic malignant cells following contact with bone marrow stroma

• Activation of the Notch-1 pathway protects myeloma cells from drug-induced apoptosis

• Activation of Notch-1 causes up regulation of p21 and growth inhibition of myeloma cells

• Overexpression of Notch-1 restored drug-resistant phenotype of Notch-1 deficient myeloma cells