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.
University Department of Haematology, Royal Liverpool University Hospital, and School of Biological Sciences, University of Liverpool, UK.
R E
RE
Clark
J
J
Grzybowski
C M
CM
Broughton
N T
NT
Pender
D G
DG
Spiller
C G
CG
Brammer
R V
RV
Giles
D M
DM
Tidd
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