globotriaosylceramide and Multiple-Myeloma

The ribosome-inactivating protein, Shiga-like toxin-1 (SLT-1), targets cells that express the glycolipid globotriaosylceramide (CD77) on their surface. CD77 and/or SLT-1 binding was detected by flow cytometry and immunocytochemistry on lymphoma and breast cancer cells recovered from biopsies of primary human cancers as well as on B cells or plasma cells present in blood/bone marrow samples of multiple myeloma patients. Breast cancer cell lines also expressed receptors for the toxin and were sensitive to SLT-1. Treatment of primary B lymphoma, B-cell chronic lymphocytic leukemia, and myeloma B or plasma cells with SLT-1-depleted malignant B cells by 3- to 28-fold, as measured by flow cytometry. Depletion of myeloma plasma cells was confirmed using a cellular limiting dilution assay followed by reverse transcriptase-polymerase chain reaction analysis of clonotypic IgH transcripts, which showed a greater than 3 log reduction in clonotypic myeloma cells after SLT-1 treatment. Receptors for the toxin were not detected on human CD34(+) hematopoietic progenitor cells (HPC). HPC were pretreated with a concentration of SLT-1 known to purge primary malignant B cells and cultured for 6 days. The number of HPC was comparable in toxin-treated and untreated cultures. HPC were functionally intact as well. Colony-forming units (CFU) were present at an identical frequency in untreated and SLT-1 pretreated cultures, confirming that CFU escape SLT-1 toxicity. The results suggest the ex vivo use of SLT-1 in purging SLT-1 receptor-expressing malignant cells from autologous stem cell grafts of breast cancer, lymphoma, and myeloma patients.

Topics: Antibodies, Monoclonal; B-Lymphocytes; Bacterial Toxins; Biomarkers; Biomarkers, Tumor; Blood Cells; Bone Marrow Cells; Bone Marrow Purging; Breast Neoplasms; Carcinoma; Cell Separation; Cells, Cultured; Colony-Forming Units Assay; Female; Flow Cytometry; Genes, Immunoglobulin; Glycolipids; Hematopoietic Stem Cell Transplantation; Hematopoietic Stem Cells; Humans; Immunoglobulin Heavy Chains; Lymphoma, B-Cell; Lymphoma, Follicular; Male; Multiple Myeloma; Neoplasm Proteins; Neoplastic Stem Cells; Organ Specificity; Plasma Cells; Receptors, Cell Surface; Reverse Transcriptase Polymerase Chain Reaction; Shiga Toxin 1; Transplantation, Autologous; Trihexosylceramides; Tumor Cells, Cultured; Tumor Stem Cell Assay

Functionally defined clones and lines of murine lymphocytes including myelomas, helper, suppressor and cytolytic T lymphocytes were analyzed for their glycosphingolipids (GSLs). GSLs were characterized by thin-layer chromatography and by high-performance liquid chromatography. Lymphocytes with different functions displayed, besides a number of common GSLs, some characteristic GSLs that may be regarded as markers. Globotriaosylceramide was found on myelomas and B blasts, whereas globotetraosylceramide was confined to helper T cells. All T cells including cytolytic T lymphocytes displayed gangliotetraosylceramide (asialo-GM1) as a major GSL, which was further characterized by sequential degradation with exoglycosidases.

Topics: Animals; Cell Line; Clone Cells; G(M1) Ganglioside; Globosides; Glycosphingolipids; Male; Mice; Mice, Inbred CBA; Mice, Inbred DBA; Multiple Myeloma; T-Lymphocytes, Cytotoxic; T-Lymphocytes, Helper-Inducer; T-Lymphocytes, Regulatory; Trihexosylceramides