B-chronic lymphocytic leukemia cells contain both endogenous kappa immunoglobulin mRNA and critical immunoglobulin gene activation transcription factors

Leukemia. 1992 Jul;6(7):675-9.

Abstract

B-cell chronic lymphocytic leukemia (B-CLL) is a hematologic malignancy characterized by the proliferation and accumulation of mature-looking B lymphocytes. Patients with B-CLL exhibit a number of immune defects including: auto-antibodies, depressed cell-mediated immunity and hypogammaglobulinemia (HG). We investigated the control of Ig production in the malignant CLL B-cell at a transcriptional and translation level. We isolated fresh leukemic B-cells from CLL patients and analyzed for the presence of nuclear factors OCT-1, OCT-2, and NF-KB. Malignant B-cells were purified to greater than 90% B-cells, and total cellular RNA and nuclear proteins were isolated from these cells. Mobility shift assays were probed with 32P-labeled oligonucleotides specific to the immunoglobulin (Ig) enhancer and promotor regions. We detected endogenous OCT-1, OCT-2, and NF-KB in all patients tested (n = 5). We then evaluated whether activation of CLL B cells could augment kappa-mRNA levels. CLL cells (n = 3) exposed to phorbol ester and A23187 were harvested at 0, 2, 4, 8, and 48 min and examined for kappa-mRNA by Northern blot. All CLL patients (n = 3) had easily detectable levels of endogenous kappa-mRNA. However, only one patient had an obvious increase in kappa-mRNA post-induction with TPA/A23187. There was no concomitant increase in this patient's OCT-1, OCT-2, or NF-KB level. This finding prompted us to survey other B-CLL patients (n = 6) for Ig nuclear transcriptional factors pre- and post-induction. In summary, CLL B cells express Ig transcriptional factor OCT-1, OCT-2, and NF-KB constitutively. The endogenous level of NF-KB may account for the basal kappa-mRNA detected in B-CLL cells. However, the inability to augment NF-KB levels may, in part, explain the low levels of Ig synthesis in CLL B-cells.

Publication types

  • Research Support, U.S. Gov't, Non-P.H.S.
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Base Sequence
  • Calcimycin / pharmacology
  • Cell Nucleus / metabolism
  • DNA-Binding Proteins / metabolism
  • Gene Expression Regulation, Neoplastic
  • Genes, Immunoglobulin*
  • Humans
  • Immunoglobulin kappa-Chains / genetics*
  • In Vitro Techniques
  • Leukemia, Lymphocytic, Chronic, B-Cell / genetics*
  • Molecular Sequence Data
  • NF-kappa B / metabolism
  • Octamer Transcription Factor-2
  • Oligodeoxyribonucleotides / chemistry
  • RNA, Messenger / genetics
  • RNA, Neoplasm / genetics
  • Transcription Factors / metabolism*
  • Transcriptional Activation
  • Tumor Cells, Cultured

Substances

  • DNA-Binding Proteins
  • Immunoglobulin kappa-Chains
  • NF-kappa B
  • Octamer Transcription Factor-2
  • Oligodeoxyribonucleotides
  • POU2F2 protein, human
  • RNA, Messenger
  • RNA, Neoplasm
  • Transcription Factors
  • Calcimycin