autologous blood and marrow transplantation - Blog Science ...

Carlo-Stella et al. 129
INTRODUCTION
CML is associated with a specific chromosomal abnormality known as the
Philadelphia chromosome, which results from a reciprocal translocation between
chromosomes 9 and 22 and fuses genetic sequences of the BCR gene on
chromosome 22 with c-ABL sequences translocated from chromosome 9. 1,2
The
resulting BCR-ABL gene generates fusion proteins with dysregulated PTK
activity 3
and transforming activity for hematopoietic cells. 4
Although considered with growing interest in CML, autologous stem cell
transplantation (autoSCT) requires improvement either by purging of the leukemic
stem cells or selection of the nonleukemic stem cells. 5
Selection strategies have
focused either on in vivo 6,7
or in vitro 8-15
purging. Targeting the tyrosine kinase
activity of BCR-ABL has been proposed as an attractive therapeutic strategy due
to the potential for malignant transformation of this kinase activity. 16
Inhibition of the BCR-ABL PTK activity has been obtained with nonselective
compounds, such as genistein, as well as selective compounds, such as herbimycin
1 7 1 8
A. Recently, a selective inhibition of the BCR-ABL tyrosine kinase activity has
been demonstrated with the 2-phenylaminopyrimidine derivative CGP57148B. 19
' 20
Tyrphostins represent an additional family of PTK inhibitors acting as competitive
inhibitors of protein substrate and/or ATP binding. 21
It was therefore the aim of the present study to investigate the differential
effects of graded concentration of AG957 on the in vitro growth of CML and
normal hematopoietic progenitors. The capability of AG957 to select in vitro for
BCR-ABL-negative progenitors was analyzed by detecting the BCR-ABL mRNA
on single progenitors by RT-PCR. We also studied the apoptotic effect of AG957
on a BCR-ABL-positive and -negative cell line.
MATERIALS AND METHODS
Patients
Eight patients (median age 46 years; range 38-61) with a diagnosis of Ph-
positive CML in chronic phase were studied. Five patients were studied at
diagnosis and before any treatment, whereas three patients had received
hydroxyurea and/or IFN-a therapy for 4 to 16 months before being studied. All
patients were 100% Ph-positive on direct cytogenetic analysis.
Cell separation procedures
CML marrow cells were obtained by aspiration from the posterior iliac crest. Normal
cells were obtained from healthy donors undergoing peripheral blood progenitor cell