Clinical use of streptolysin-O to facilitate antisense oligodeoxyribonucleotide delivery for purging autografts in chronic myeloid leukaemia.
Antisense oligodeoxyribonucleotides (ODN) targeted against the breakpoint in BCR-ABL mRNA will specifically decrease BCR-ABL mRNA, provided cells are first permeabilised with streptolysin-O (SL-O). We used 18-mer chimeric methylphosphonodiester: phosphodiester linked (4-9-4) ODN complementary to 9 bases either side of the BCR-ABL junction to purge harvests ex vivo in three CML patients who remained completely Ph positive after multiple chemotherapy courses. After CD34+ cell selection and SL-O permeabilisation, harvests were purged with 20 microM ODN. After purging, all individual CFU-GM colonies grown from the two b3a2 breakpoint cases remained positive for BCR-ABL mRNA. In contrast, all 24 colonies grown from the b2a2 breakpoint case were BCR-ABL mRNA negative. Patients were conditioned with busulphan 16 mg/kg. The initial post-transplant course was uneventful, although the time to return to 0.5 x 10(9)/l neutrophils was slow at 25-51 days. Both chronic phase patients remain in haematological remission at +724 and +610 days, although each has cytogenetic evidence of relapse. The b2a2 accelerated phase patient died of myeloid blast transformation at day +91. The present SL-O-facilitated ODN purging strategy appears to be without significant toxicity, and offers considerable improvements in ODN delivery to the cytosol.
Clark
R E
RE
University Department of Haematology, Royal Liverpool University Hospital, and School of Biological Sciences, University of Liverpool, UK.
Grzybowski
J
J
Broughton
C M
CM
Pender
N T
NT
Spiller
D G
DG
Brammer
C G
CG
Giles
R V
RV
Tidd
D M
DM
D018952:Antigens, CD34; D016044:Fusion Proteins, bcr-abl / Q000235:genetics*; D019650:Hematopoietic Stem Cell Mobilization; D018380:Hematopoietic Stem Cell Transplantation / Q000379:methods*; D006801:Humans; D007937:Leukapheresis; D015464:Leukemia, Myelogenous, Chronic, BCR-ABL Positive / Q000628:therapy*; D016376:Oligonucleotides, Antisense / Q000008:administration & dosage / Q000627:therapeutic use*; D017063:Outcome Assessment, Health Care; D017422:Sequence Analysis, DNA; D019172:Transplantation Conditioning / Q000379:methods*
D018952:Antigens, CD34; D016376:Oligonucleotides, Antisense; D016044:Fusion Proteins, bcr-abl