Format

Send to:

Choose Destination
See comment in PubMed Commons below
Exp Hematol Oncol. 2013 Apr 10;2(1):11. doi: 10.1186/2162-3619-2-11.

Vincristine could partly suppress stromal support to T-ALL blasts during pegylated arginase I treatment.

Author information

  • 1Department of Paediatrics & Adolescent Medicine, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, SAR, China. gcfchan@hku.hk.

Abstract

BACKGROUND:

Relapsed T-lineage acute lymphoblastic leukemia (T-ALL) has been an incurable disease. Recent reports showed that an L-arginine depleting enzyme, pegylated arginase (BCT-100) may be effective against T-ALL cells. On the other hand, studies including ours had shown the symbiosis of ALL blasts and human mesenchymal stromal cells (hMSCs) in bone marrow microenvironment during L-asparaginase treatment. As L-asparaginase and BCT-100 both act by depleting lymphoid cells of specific amino acid, we hypothesized that hMSCs may also protect T-ALL blasts from BCT-100 treatment in co-culture and such protection may be abrogated by pre-treating hMSCs with vincristine (VCR).

METHODS:

XTT assay was used to test sensitivities of T-ALL cell lines and hMSCs to BCT-100. Apoptosis of T-ALL cell lines with or without BCT-100 treatment were tested by annexin V / propidium iodide (AV/PI) assay using flow cytometer. Western blotting was performed to analyze the expression of ornithine transcarbamylase (OTC), an enzyme involved in L-arginine metabolism which may account for BCT-100 resistance.

RESULTS:

hMSCs were resistant to BCT-100 while CCRF-CEM, Jurkat and MOLT-4 were very sensitive to it. hMSCs could protect all the three cell lines from BCT-100 treatment in transwell co-culture. All the 3 T-ALL cell lines were also found to be rescued by an L-arginine precursor citrulline, while the breakdown product of BCT-100, ornithine only had limited salvaging effect on CCRF-CEM but not Jurkat and MOLT-4. Both hMSCs and 3 T-ALL cell lines express citrulline synthesis enzyme, ornithine transcarbamylase (OTC) at basal level while only hMSCs could express OTC at relatively higher level under BCT-100 treatment. Treating hMSCs with vincristine before co-culturing with T-ALL could resume the cytotoxicity of BCT-100 to CCRF-CEM and MOLT-4 cells.

CONCLUSIONS:

Our results suggest a possible strategy to overcome resistance to BCT-100 from cancer microenvironments by suppressing hMSCs either in marrow or in the perivascular niche using vincristine.

PMID:
23574711
[PubMed]
PMCID:
PMC3655039
Free PMC Article
PubMed Commons home

PubMed Commons

0 comments
How to join PubMed Commons

    Supplemental Content

    Full text links

    Icon for PubMed Central
    Loading ...
    Write to the Help Desk