Increased apoptosis in B-chronic lymphocytic leukemia cells as a result of cyclin D3 down regulation

Leuk Lymphoma. 2002 Sep;43(9):1827-35. doi: 10.1080/1042819021000006411.

Abstract

B-cell chronic lymphocytic leukemia (CLL) is a clonal B cell malignancy of morphologically mature, functionally immature B cells. B-cell CLL cells are known to be resistant to killing by anticancer and other agents. This resistance is associated with alterations in apoptosis and cell cycle regulated genes. In our earlier studies, we have demonstrated that CLL cells have differential expression of genes that are associated with apoptosis and cell cycle regulation, including elevated expression of Bcl-2, DAD-1, Cyclin D3 and cyclin dependent kinase 4 inhibitor. Therefore, in this study, in an attempt to study the role of Cyclin D3 in the resistant behavior of CLL cells, Cyclin D3 was down regulated using antisense oligonucleotide (AS-ODN) in WSU-CLL, a human CLL cell line. The down regulation of Cyclin D3 was confirmed by RT-PCR and flow cytometry techniques. The Cyclin D3 expression down-regulated WSU-CLL cells were then tested for their susceptibility to fludarabine, a chemotherapeutic agent. Our results showed that the Cyclin D3 expression down-regulated WSU-CLL cells were more susceptible to fludarabine mediated killing. Following treatment with fludarabine, there was a significant increase in the number of cells undergoing apoptosis in Cyclin D3 expression down-regulated WSU-CLL cells as determined by Annexin-V assay, cell cycle analysis for DNA content, and cytomorphology. Thus, our results indicate Cyclin D3 down regulation increases the killing of WSU-CLL cells with fludarabine by increasing the number of cells undergoing apoptosis.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Annexin A5 / pharmacology
  • Apoptosis Regulatory Proteins
  • Apoptosis*
  • Caenorhabditis elegans Proteins*
  • Cell Cycle
  • Cell Division
  • Cell Line, Tumor
  • Coloring Agents / pharmacology
  • Cyclin D3
  • Cyclin-Dependent Kinase 4
  • Cyclin-Dependent Kinases / antagonists & inhibitors
  • Cyclins / biosynthesis*
  • Cyclins / metabolism
  • Down-Regulation*
  • Fluorescein-5-isothiocyanate / pharmacology
  • Humans
  • Leukemia, Lymphocytic, Chronic, B-Cell / metabolism*
  • Leukemia, Lymphocytic, Chronic, B-Cell / pathology*
  • Oligonucleotides, Antisense / pharmacology
  • Proto-Oncogene Proteins c-bcl-2 / metabolism
  • Proto-Oncogene Proteins*
  • Repressor Proteins / metabolism
  • Reverse Transcriptase Polymerase Chain Reaction
  • Tetrazolium Salts / pharmacology
  • Thiazoles / pharmacology
  • Vidarabine / analogs & derivatives*
  • Vidarabine / therapeutic use

Substances

  • Annexin A5
  • Apoptosis Regulatory Proteins
  • CCND3 protein, human
  • Caenorhabditis elegans Proteins
  • Coloring Agents
  • Cyclin D3
  • Cyclins
  • Dad-1 protein, C elegans
  • Oligonucleotides, Antisense
  • Proto-Oncogene Proteins
  • Proto-Oncogene Proteins c-bcl-2
  • Repressor Proteins
  • Tetrazolium Salts
  • Thiazoles
  • CDK4 protein, human
  • Cyclin-Dependent Kinase 4
  • Cyclin-Dependent Kinases
  • thiazolyl blue
  • Vidarabine
  • Fluorescein-5-isothiocyanate
  • fludarabine