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NEOPLASIA
From the Division of Hematology and Medical Oncology,
Oregon Health Sciences University, Portland, OR.
Chronic myelogenous leukemia (CML), a malignancy of a hematopoietic
stem cell, is caused by the Bcr-Abl tyrosine kinase. STI571(formerly CGP 57148B), an Abl tyrosine kinase inhibitor, has specific in vitro
antileukemic activity against Bcr-Abl-positive cells and is currently
in Phase II clinical trials. As it is likely that resistance to a
single agent would be observed, combinations of STI571 with other
antileukemic agents have been evaluated for activity against
Bcr-Abl-positive cell lines and in colony-forming assays in vitro. The
specific antileukemic agents tested included several agents currently
used for the treatment of CML: interferon-alpha (IFN), hydroxyurea
(HU), daunorubicin (DNR), and cytosine arabinoside (Ara-C). In
proliferation assays that use Bcr-Abl-expressing cells lines, the
combination of STI571 with IFN, DNR, and Ara-C showed additive or
synergistic effects, whereas the combination of STI571 and HU
demonstrated antagonistic effects. However, in colony-forming assays
that use CML patient samples, all combinations showed increased antiproliferative effects as compared with STI571 alone. These data
indicate that combinations of STI571 with IFN, DNR, or Ara-C may be
more useful than STI571 alone in the treatment of CML and suggest
consideration of clinical trials of these combinations.
(Blood. 2000;96:3195-3199) Chronic myelogenous leukemia (CML) is a
hematopoietic stem cell disorder. In the chronic phase of the disease,
there are excess numbers of myeloid cells; however, these cells
differentiate and function normally. Over time, there is a progressive
loss of terminal differentiation, and the disease terminates in an
acute leukemia, known as blast crisis. Blast crisis is usually of
myeloid phenotype, but, in up to one third of patients, a lymphoid
phenotype is seen. In all phases of the disease, leukemic cells contain
the Philadelphia (Ph) chromosome.1 In addition,
approximately 20% of adults and 5% of children with acute
lymphoblastic leukemia (ALL) are Ph chromosome positive.1
On a molecular level, the Ph chromosome results in the juxtaposition of
Bcr and Abl sequences, leading to a chimeric messenger RNA and protein
termed Bcr-Abl.2,3 Virtually all cases of CML express a
210-kd form of Bcr-Abl, whereas 50% of adults and 95% of children
with Ph-positive ALL express a shorter version of Bcr-Abl, termed p185
or 190 Bcr-Abl.1,4
Current standard treatments for CML include stem cell transplantation,
interferon (IFN)-alpha-containing regimens, and hydroxyurea (HU).
Allogeneic stem cell transplantation is the only curative therapy.
Long-term survival from this procedure is approximately 65%; however,
only one third of patients are eligible for this procedure because of
the lack of availability of a donor or because of concerns regarding
mortality with advancing age. Thus, the overall cure rate for CML is
less than 20%.4-6 IFN can prolong survival by an average
of up to 2 years as compared with HU, and there is evidence that the
addition of cytosine arabinoside (Ara-C) to IFN improves response rate
and survival.7-9 In the blast phase of the disease,
patients are typically refractory to standard induction chemotherapy
regimens, particularly with myeloid disease phenotype.4,5
Patients with Ph chromosome-positive ALL have a worse prognosis than
do patients with normal cytogenetics.10,11
Bcr-Abl is a constitutively activated tyrosine kinase that has been
shown to be the cause of CML with tyrosine kinase activity being
essential to the function of the Bcr-Abl protein.12-14
Recent clinical trials with STI571, a specific inhibitor of the Bcr-Abl tyrosine kinase, have shown this compound to have significant activity
in all phases of CML as well as Ph chromosome-positive acute
leukemias.15,16 However, in patients with acute leukemias, relapses have been a major problem.15 This situation
raises the possibility that later relapses will also be seen in chronic phase patients because of resistance to STI571. In this study, combinations of STI571 with several antileukemic agents were
investigated, including IFN, HU, daunorubicin (DNR), and Ara-C. These
studies were performed to determine whether these combinations would
enhance the activity of STI571 and whether these combinations might be useful in an attempt to circumvent resistance.
Reagents
Cell lines and culture conditions
MO7p210, a derivative of MO7e engineered to express Bcr-Abl,18 and K562, a Bcr-Abl-positive CML blast crisis patient cell line,19 were grown in RPMI-1640 medium supplemented with 10% (v/v) FBS, 2% L-glutamine, and 1% pen/strep. All cell lines were grown in 5% CO2/95% O2 air, in a 37°C fully humidified incubator. MTT assays Cells were plated at a concentration of 5 × 103 cells per well. Each concentration of drug alone and in combination with STI571 was assayed in quadruplicate. Controls were performed, using identical dilutions of medium with identical concentrations of solvent used for STI571 and the antileukemic agents. Each plate contained serial dilutions of cells to ensure that a linear relationship between optical density (OD) and cell number was maintained. Wells were assayed for uptake of MTT at daily intervals as described.20 Plates were read with a 96-well scanning spectrophotometer at 570 nm and reported as ODs. The mean and standard deviation were calculated for each concentration and combination and were reported as the percentage of growth versus control. Cell proliferation curves were generated from these data, and results from day 3 were used to assess for activity. The percentage of inhibition of proliferation is calculated as 1 (OD MO7p210 + drug/OD
MO7p210) × 100. To evaluate antagonistic, additive, or synergistic
effects of drug combinations, isobolograms were generated from the
inhibitory concentrations with the highest number of data points and
plotted as a function of the concentration of IFN, DNR, Ara-C, or HU
versus the concentration of STI571.
Colony-forming assays Colony-forming assays were performed on bone marrow and peripheral blood samples of 4 CML patients. Each of these patients was in late chronic phase or early accelerated phase of the disease, had failed a trial of IFN, and were off all therapy for at least 1 week. Bone marrow or blood samples were collected after obtaining informed consent. Five milliliters of bone marrow or 10 mL of peripheral blood was diluted 1:4 with warmed Iscove modified Dulbecco media (IMDM; Gibco BRL), layered over Ficoll-Paque (Amersham Pharmacia, Uppsala, Sweden), and centrifuged at 1300 rpm for 20 minutes at 20°C. Mononuclear cells were aspirated from the density interface, resuspended in 15 mL of IMDM, and pelleted by centrifugation at 1000 rpm for 10 minutes at 20°C. After resuspension in IMDM, viable cells were counted by trypan blue exclusion and diluted to a concentration of 5 × 105 cells/mL. Cells were diluted 1:10 in methylcellulose media containing erythropoietin and interleukin-3 (IL-3) for burst-forming unit, erythroid (BFU-E) assays (Methocult GF H4434, Stem Cell Technologies, Vancouver, BC), or GM-CSF and IL-3 for colony-forming unit-granulocyte-macrophage (CFU-GM) assays (Methocult GF H4534, Stem Cell Technologies). Cells (5 × 104) were plated in 35-mm cell culture dishes. A range of concentrations and combinations of STI571 and other antileukemic agents were assayed in duplicates. After a 2-week incubation at 37°C, BFU-E and CFU-GM were counted. Results were calculated as the percentage of growth versus control.Statistical analysis BFU-E and CFU-GM are expressed as the percentage of inhibition versus control, and the mean and standard deviation of colony inhibition for each dose of drug and each combination were calculated across all patient samples. Nonpaired, single-tail t tests were used to evaluate efficacy of STI571 and drugs versus STI571 alone, as well as STI571 and drugs versus drug alone.
Cellular proliferation studies Three cell lines were analyzed for inhibition of proliferation by STI571 and a variety of antileukemic agents, HU, IFN, Ara-C, and DNR. The 3 cell lines chosen for this analysis were MO7e cells, a human megakaryoblastic cell line that requires either GM-CSF, IL-3, or steel factor (SF) for survival or proliferation; MO7p210 cells, a derivative of the MO7e cell line, engineered to express Bcr-Abl; and K562 cells, a Bcr-Abl-positive human cell line derived from a CML patient in blast crisis. Initial experiments were performed with a wide range of concentrations of STI571 and each of the antileukemic agents to establish an approximation of a 50% inhibitory concentration (IC50). Additional experiments were then performed by using a narrower range of concentrations to determine whether additive, synergistic, or antagonistic effects of STI571 were seen with each of the antileukemic agents.The results presented in Figure 1 plot
the percentage of inhibition of proliferation of the MO7p210 cells
after 3 days in the continuous presence of HU, IFN, DNR, or Ara-C alone
as compared with 0.05 µmol/L STI571 combined with each of these
agents. In these graphs, the antileukemic activity of STI571 alone is
indicated by the intersection with the y-axis. Each data point
represents the mean of 4 wells from 1 of 3 separate experiments. To
determine the relationship between the percentage of inhibition of
proliferation and drug concentrations, a best fit regression line was
generated. R2 values indicate the percentage of data that
can be accounted for by the regression line. For all of the
antileukemic agents, except HU, there is a substantial shift in the
curves, consistent with increased antiproliferative activity of the
combinations. Similar data were obtained by using 0.025 and 0.1 µmol/L STI571 (data not shown). As the highest clustering of data
points in Figure 1 was at or near an IC60 for the combinations, these
regression lines were used to estimate an IC60 for each of the
combinations as compared with each of the antileukemic agents alone
(Table 1).
MO7e cell line When grown in GM-CSF, MO7e cells were not inhibited by concentrations of STI571 of up to 10 µmol/L. In contrast, the growth of MO7e cells was easily inhibited by various concentrations of antileukemic agents, IFN, DNR, HU, and Ara-C. As predicted, there was no change in the inhibition of proliferation of MO7e cells when STI571 was added to IFN, DNR, HU, or Ara-C compared with each of the antileukemic agents alone (Table 1).MO7p210 cell line MO7p210 cells have previously been shown to be highly sensitive to STI571.21 Consistent with the known resistance to antileukemic agents imparted by Bcr-Abl expression, MO7p210 cells required higher concentrations of each of the antileukemic agents, except IFN, for inhibition of cellular proliferation, as compared with MO7 cells (Table 1). However, when STI571 was combined with IFN, DNR, or Ara-C, the IC60s for these agents dropped to concentrations lower or equal to those of the MO7e parental cell line. There was no change in the IC60 when STI571 was combined with HU (Table 1).K562 cell line Identical experiments were performed with K562 cells, a Bcr-Abl-positive human cell line derived from a CML patient in blast crisis. Concentrations of 0.1, 0.25, and 0.5 µmol/L STI571 were combined with each of the antileukemic agents. A 40% to 45% inhibition of proliferation was seen with the use of 0.25 µmol/L STI571. Thus, this dose was selected to construct graphs similar to those in Figure 1 for the K562 cell lines. Regression lines were generated for each of the combinations, and IC60 concentrations were determined from these graphs (Table 1). Similar to the MO7p210 cells, K562 cells demonstrated substantially higher IC60s for DNR, HU, and Ara-C than the MO7e cell line (Table 1). Again, with the exception of HU, combining each of the antileukemic agents with STI571 resulted in a substantial decrease in the IC60s (Table 1).For the K562 cells, enough data points were clustered at various
inhibitory concentrations of each of the combinations to construct
isobolograms (Figure 2). Thus, for the
combination of Ara-C and STI571, the IC50s and IC80s were used, whereas
IC75s were used for the combination of DNR with STI571 as indicated in
Figure 2. In this analysis, a straight line would represent an additive
effect, a downward bowing curve a synergistic effect, and an upward
bowing curve an antagonistic effect. As with the MO7p210 cells, the
combinations of STI571 plus IFN or DNR produced additive antileukemic
effects, whereas STI571 plus Ara-C produced the most substantial
increase in inhibition of proliferation, consistent with a synergistic
effect. R2 values, indicating the degree of fit for the
generation of the regression lines, were all more than 0.74, demonstrating a high degree of confidence in these regression lines.
Colony-forming assays Colony-forming assays that used bone marrow or peripheral blood samples from 4 CML patients were performed, and BFU-E and CFU-GM were counted. In these assays, STI571 was again analyzed in combination with HU, IFN, DNR, or Ara-C. All 4 of the patients were in late chronic phase or early accelerated phase of the disease. Blood or marrow samples were obtained with patients who had been off all therapies for at least 1 week; thus, circulating drug levels were not likely to be a confounding variable in these assays.In Figure 3, the data for CFU-GM and
BFU-E are shown. In this figure, data are plotted that compare STI571
alone as the basis for comparison with each additional line,
representing a different dose of the various antileukemic agents. Data
were plotted in this manner, as there was consistent inhibition of
colony formation for all patients at each dose of STI571, whereas there
was significant interpatient variability with the different
antileukemic agents. As can be seen in Figure 3, STI571 in combination
with IFN, DNR, or Ara-C produced substantial decreases in colony
formation. This increased inhibition of colony formation was seen in
both CFU-GM and BFU-E and is consistent with the cell line
proliferation assays. In most of these combinations, the decrease in
colony formation by adding STI571 to either IFN, DNR, or Ara-C was
statistically significant. However, in contrast to the results of the
MO7p210 and K562 cell line assays, combinations of STI571 with HU also demonstrated significant inhibition of colony formation.
In this study, the combination of STI571 with various antileukemic agents was investigated. The major conclusion from the data is that the addition of standard agents used for the treatment of various stages of CML adds to the antiproliferative activities of STI571. The only exception to this conclusion was that HU appeared antagonistic in cell lines; however, it did improve on STI571 when analyzed in colony-forming assays that used CML patient samples. This discrepancy could be due to the difference in the assay systems, differences in cellular phenotype, or other unknown factors. The possibility of antagonism between STI571 and antileukemic agents was a major reason for undertaking these studies. In colony-forming assays that used chronic phase CML patient samples, we have previously demonstrated that STI571 selects for the growth of benign hematopoietic progenitors.21 However, attempts to eliminate the Bcr-Abl-positive clone by incubating STI571 with CD34+ cells in the presence of a variety of cytokines have failed (B.J.D., unpublished data, June 1996). The most likely explanation for this discrepancy is that colony-forming assays require cellular proliferation, whereas, for the in vitro purging experiments, cells may remain quiescent. Thus, we hypothesized that inhibition of cellular proliferation with antileukemic agents may protect Bcr-Abl-expressing cells from STI571. As seen, with the exception of HU, this situation was not the case. Having demonstrated that STI571 improves the in vitro benefits from antileukemic agents, further studies are warranted to elucidate the mechanism of this enhancement. STI571 is known to induce apoptosis of Bcr-Abl-expressing cell lines.21-23 Thus, it is possible that the same or different apoptotic pathways are used by STI571 as compared with the other antileukemic agents to explain additive or synergistic effects. Whether cell cycle-dependent effects of these agents are also operational is also worthy of investigation. The results presented in this study are consistent with the findings that Bcr-Abl expression renders cells resistant to chemotherapeutic agents.24,25 As seen, both MO7p210 and K562 cells required higher doses of antileukemic agents for cell killing than did M07 cells. However, treatment of the Bcr-Abl-expressing cells with STI571 rendered these cells susceptible to cell killing at concentrations of the antileukemic agents similar to the concentration required to kill MO7 cells. These data suggest that the Bcr-Abl-resistance phenotype can be completely reversed by treating cells with STI571. We chose low-dose, continuous exposure to the antileukemic agents rather than investigating all possible combinations of doses and schedules. This investigation was done specifically to evaluate whether STI571 would increase the sensitivity of Bcr-Abl-expressing cells to antileukemic agents. Thus, the experiments presented in the study are most obviously applicable to chronic phase patients whose current treatment regimens include low-dose, continuous exposure to agents, such as IFN and Ara-C. In particular, the colony-forming data validate the rationale for clinical trials of these combinations in chronic phase patients. In acute leukemia patients, antileukemic agents are typically given as high-dose bolus infusions. By reversing the chemotherapy resistance phenotype of Bcr-Abl-expressing cell lines, it is also possible that STI571 will enhance the benefits from standard chemotherapy regimens used for the treatment of Bcr-Abl acute leukemias. As relapses in blast crisis patients treated with STI571 are a major problem,15 and blast crisis patients are highly resistant to standard chemotherapy, these data suggest that combinations of STI571 with standard antileukemic agents are a viable approach to the treatment of Bcr-Abl acute leukemias. Despite the dramatic results with the use of STI571 to treat patients with chronic phase CML who have failed IFN therapy,16 the major questions being addressed in ongoing clinical trials of STI571 in these chronic phase patients are the duration of responses and whether it will be possible to completely eradicate the leukemic clone. As Bcr-Abl is thought to contribute to the genetic instability responsible for disease progression,26 it is possible that long-term therapy with STI571 without eradication of Bcr-Abl could also improve survival. In any case, it is possible that resistance would develop with long-term administration of STI571 without elimination of the leukemic clone or that side effects from long-term administration would be observed. Thus, the preferable approach would be to combine STI571 with other agents to either prevent the emergence of resistant clones or to enhance the eradication of the leukemic clone. Although the data suggests that Ara-C may be the best partner with STI571 in terms of synergy, caution in overinterpreting this finding is warranted. In particular, all of the patients whose samples were used in colony-forming assays had failed a trial of IFN. Thus, the benefits from the STI571/IFN combination may be underestimated from these in vitro studies. However, these data suggest that clinical trials with these combinations are worth pursuing. On the basis of these in vitro data, clinical trials are planned that use the combination of STI571 with IFN and STI571 with low-dose Ara-C. In addition, trials of combinations of STI571 with standard induction chemotherapy are planned for patients with CML blast crisis and Ph + ALL.
Submitted March 3, 2000; accepted July 10, 2000.
Supported by National Institutes of Health grant CA65823. B.J.D. is a recipient of a Translational Research Award from the Leukemia and Lymphoma Society.
The publication costs of this article were defrayed in part by page charge payment. Therefore, and solely to indicate this fact, this article is hereby marked "advertisement" in accordance with 18 U.S.C. section 1734.
Reprints: Brian J. Druker, Division of Hematology and Medical Oncology, L592, Oregon Health Sciences University, 3181 SW Sam Jackson Park Rd, Portland, OR 97201; e-mail: drukerb{at}ohsu.edu.
1. Kurzrock R, Gutterman JU, Talpaz M. The molecular genetics of Philadelphia chromosome-positive leukemias. N Engl J Med. 1988;319:990-998[Medline] [Order article via Infotrieve]. 2. Shtivelman E, Lifshitz B, Gale RP, Canaani E. Fused transcript of abl and bcr genes in chronic myelogenous leukaemia. Nature. 1985;315:550-554[Medline] [Order article via Infotrieve].
3.
Konopka JB, Watanabe SM, Singer JW, Collins SJ, Witte ON.
Cell lines and clinical isolates derived from Ph1-positive chronic myelogenous leukemia patients express c-abl proteins with a common structural alteration.
Proc Natl Acad Sci U S A.
1985;82:1810-1814
4.
Faderl S, Talpaz M, Estrov Z, et al.
The biology of chronic myeloid leukemia.
N Engl J Med.
1999;341:164-172
5.
Sawyers CL.
Chronic myeloid leukemia.
N Engl J Med.
1999;340:1330-1340 6. Goldman JM. Treatment of chronic myeloid leukaemia: some topical questions. Baillieres Clin Haematol. 1997;10:405-421[Medline] [Order article via Infotrieve].
7.
Silver RT, Woolf SH, Hehlmann R, et al.
An evidence-based analysis of the effect of busulfan, hydroxyurea, interferon, and allogeneic bone marrow transplantation in treating the chronic phase of chronic myeloid leukemia: developed for the American Society of Hematology.
Blood.
1999;94:1517-1536
8.
Chronic Myeloid Leukemia Trialists' Collaborative Group.
Interferon alfa versus chemotherapy for chronic myeloid leukemia: a meta-analysis of seven randomized trials.
J Natl Cancer Inst.
1997;89:1616-1620
9.
Guilhot F, Chastang C, Michallet M, et al.
Interferon alfa-2B combined with cytarabine versus interferon alone in chronic myelogenous leukemia.
N Engl J Med.
1997;337:223-229 10. Uckun FM, Nachman JB, Sather HN, et al. Clinical significance of Philadelphia chromosome positive pediatric acute lymphoblastic leukemia in the context of contemporary intensive therapies: a report from the Children's Cancer Group. Cancer. 1998;83:2030-2039[Medline] [Order article via Infotrieve]. 11. Preti HA, O'Brien S, Giralt S, et al. Philadelphia-chromosome-positive adult acute lymphocytic leukemia: characteristics, treatment results, and prognosis in 41 patients. Am J Med. 1994;97:60-65[Medline] [Order article via Infotrieve].
12.
Daley GQ, Van Etten RA, Baltimore D.
Induction of chronic myelogenous leukemia in mice by the P210bcr/abl gene of the Philadelphia chromosome.
Science.
1990;247:824-830
13.
Kelliher MA, McLaughlin J, Witte ON, Rosenberg N.
Induction of a chronic myelogenous leukemia-like syndrome in mice with v-abl and BCR/ABL.
Proc Natl Acad Sci U S A.
1990;87:6649-6653
14.
Lugo TG, Pendergast AM, Muller AJ, Witte ON.
Tyrosine kinase activity and transformation potency of bcr-abl oncogene products.
Science.
1990;247:1079-1082 15. Druker BJ, Kantarjian H, Sawyers CL, et al. Activity of an Abl specific tyrosine kinase inhibitor in patients with Bcr-Abl positive acute leukemias, including chronic myelogenous leukemia in blast crisis. Blood. 1999;94:697a. 16. Druker BJ, Talpaz M, Resta D, et al. Clinical efficacy and safety of an Abl specific tyrosine kinase inhibitor as targeted therapy for chronic myelogenous leukemia. Blood. 1999;94:368a. 17. Avanzi GC, Lista P, Giovinazzo B, et al. Selective growth response to IL-3 of a human leukaemic cell line with megakaryoblastic features. Br J Haematol. 1988;69:359-366[Medline] [Order article via Infotrieve].
18.
Matsuguchi T, Salgia R, Hallek M, et al.
SHC phosphorylation in myeloid cells is regulated by GM-CSF, IL-3, and steel factor and is constitutively increased by p210BCR-ABL.
J Biol Chem.
1994;269:5016-5021
19.
Lozzio CB, Lozzio BB.
Human chronic myelogenous leukemia cell line with positive Philadelphia chromosome.
Blood.
1975;45:321-334 20. Mosmann T. Rapid colorimetric assay for cellular growth and survival: application to proliferation and cytotoxicity assays. J Immunol Methods. 1983;65:55-63[Medline] [Order article via Infotrieve]. 21. Druker BJ, Tamura S, Buchdunger E, et al. Effects of a selective inhibitor of the ABL tyrosine kinase on the growth of BCR-ABL positive cells. Nat Med. 1996;2:561-566[Medline] [Order article via Infotrieve].
22.
Deininger MW, Goldman JM, Lydon N, Melo JV.
The tyrosine kinase inhibitor CGP57148B selectively inhibits the growth of Bcr-Abl-positive cells.
Blood.
1997;90:3691-3698 23. Gambacorti-Passerini C, le Coutre P, Mologni L, et al. Inhibition of the ABL kinase activity blocks the proliferation of BCR/ABL+ leukemic cells and induces apoptosis. Blood Cells Mol Dis. 1997;23:380-394[Medline] [Order article via Infotrieve].
24.
Bedi A, Zehnbauer BA, Barber JP, Sharkis SJ, Jones RJ.
Inhibition of apoptosis by BCR-ABL in chronic myeloid leukemia.
Blood.
1994;83:2038-2044 25. Nishii K, Kabarowski JH, Gibbons DL, et al. ts BCR-ABL kinase activation confers increased resistance to genotoxic damage via cell cycle block. Oncogene. 1996;13:2225-2234[Medline] [Order article via Infotrieve].
26.
Laneuville P, Sun G, Timm M, Vekemans M.
Clonal evolution in a myeloid cell line transformed to interleukin-3 independent growth by retroviral transduction and expression of p210bcr/abl.
Blood.
1992;80:1788-1797
© 2000 by The American Society of Hematology.
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 |
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  T. P. Hughes, S. Branford, D. L. White, J. Reynolds, R. Koelmeyer, J. F. Seymour, K. Taylor, C. Arthur, A. Schwarer, J. Morton, et al. Impact of early dose intensity on cytogenetic and molecular responses in chronic- phase CML patients receiving 600 mg/day of imatinib as initial therapy Blood, November 15, 2008; 112(10): 3965 - 3973. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
W. Deenik, B. van der Holt, G. E. G. Verhoef, W. M. Smit, M. J. Kersten, H. C. Kluin-Nelemans, L. F. Verdonck, A. Ferrant, A. V. M. B. Schattenberg, J. J. W. M. Janssen, et al. Dose-finding study of imatinib in combination with intravenous cytarabine: feasibility in newly diagnosed patients with chronic myeloid leukemia Blood, March 1, 2008; 111(5): 2581 - 2588. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
B. Wassmann, H. Pfeifer, N. Goekbuget, D. W. Beelen, J. Beck, M. Stelljes, M. Bornhauser, A. Reichle, J. Perz, R. Haas, et al. Alternating versus concurrent schedules of imatinib and chemotherapy as front-line therapy for Philadelphia-positive acute lymphoblastic leukemia (Ph+ALL) Blood, September 1, 2006; 108(5): 1469 - 1477. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
H. Liu, C. Zang, M. H. Fenner, D. Liu, K. Possinger, H. P. Koeffler, and E. Elstner Growth inhibition and apoptosis in human Philadelphia chromosome-positive lymphoblastic leukemia cell lines by treatment with the dual PPAR{alpha}/{gamma} ligand TZD18 Blood, May 1, 2006; 107(9): 3683 - 3692. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
A. Aloisi, S. Di Gregorio, F. Stagno, P. Guglielmo, F. Mannino, M. P. Sormani, P. Bruzzi, C. Gambacorti-Passerini, G. Saglio, S. Venuta, et al. BCR-ABL nuclear entrapment kills human CML cells: ex vivo study on 35 patients with the combination of imatinib mesylate and leptomycin B Blood, February 15, 2006; 107(4): 1591 - 1598. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 A. S. Rao, N. Kremenevskaja, R. von Wasielewski, V. Jakubcakova, S. Kant, J. Resch, and G. Brabant Wnt/{beta}-Catenin Signaling Mediates Antineoplastic Effects of Imatinib Mesylate (Gleevec) in Anaplastic Thyroid Cancer J. Clin. Endocrinol. Metab., January 1, 2006; 91(1): 159 - 168. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
S. Lee, Y.-J. Kim, C.-K. Min, H.-J. Kim, K.-S. Eom, D.-W. Kim, J.-W. Lee, W.-S. Min, and C.-C. Kim The effect of first-line imatinib interim therapy on the outcome of allogeneic stem cell transplantation in adults with newly diagnosed Philadelphia chromosome-positive acute lymphoblastic leukemia Blood, May 1, 2005; 105(9): 3449 - 3457. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
M. Deininger, E. Buchdunger, and B. J. Druker The development of imatinib as a therapeutic agent for chronic myeloid leukemia Blood, April 1, 2005; 105(7): 2640 - 2653. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
F. Guo, C. Sigua, P. Bali, P. George, W. Fiskus, A. Scuto, S. Annavarapu, A. Mouttaki, G. Sondarva, S. Wei, et al. Mechanistic role of heat shock protein 70 in Bcr-Abl-mediated resistance to apoptosis in human acute leukemia cells Blood, February 1, 2005; 105(3): 1246 - 1255. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
M. Baccarani, G. Martinelli, G. Rosti, E. Trabacchi, N. Testoni, S. Bassi, M. Amabile, S. Soverini, F. Castagnetti, D. Cilloni, et al. Imatinib and pegylated human recombinant interferon-{alpha}2b in early chronic-phase chronic myeloid leukemia Blood, December 15, 2004; 104(13): 4245 - 4251. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 S. Parmar, E. Katsoulidis, A. Verma, Y. Li, A. Sassano, L. Lal, B. Majchrzak, F. Ravandi, M. S. Tallman, E. N. Fish, et al. Role of the p38 Mitogen-activated Protein Kinase Pathway in the Generation of the Effects of Imatinib Mesylate (STI571) in BCR-ABL-expressing Cells J. Biol. Chem., June 11, 2004; 279(24): 25345 - 25352. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
J. M. Dziba and K. B. Ain Imatinib Mesylate (Gleevec; STI571) Monotherapy Is Ineffective in Suppressing Human Anaplastic Thyroid Carcinoma Cell Growth in Vitro J. Clin. Endocrinol. Metab., May 1, 2004; 89(5): 2127 - 2135. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 M. G. Mohi, C. Boulton, T.-L. Gu, D. W. Sternberg, D. Neuberg, J. D. Griffin, D. G. Gilliland, and B. G. Neel Combination of rapamycin and protein tyrosine kinase (PTK) inhibitors for the treatment of leukemias caused by oncogenic PTKs PNAS, March 2, 2004; 101(9): 3130 - 3135. [Abstract] [Full Text] [PDF]
|
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|
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|
|
P. La Rosee, K. Johnson, A. S. Corbin, E. P. Stoffregen, E. M. Moseson, S. Willis, M. M. Mauro, J. V. Melo, M. W. Deininger, and B. J. Druker In vitro efficacy of combined treatment depends on the underlying mechanism of resistance in imatinib-resistant Bcr-Abl-positive cell lines Blood, January 1, 2004; 103(1): 208 - 215. [Abstract] [Full Text] [PDF]
|
|
|
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M. Gardembas, P. Rousselot, M. Tulliez, M. Vigier, A. Buzyn, F. Rigal-Huguet, L. Legros, M. Michallet, C. Berthou, N. Cheron, et al. Results of a prospective phase 2 study combining imatinib mesylate and cytarabine for the treatment of Philadelphia-positive patients with chronic myelogenous leukemia in chronic phase Blood, December 15, 2003; 102(13): 4298 - 4305. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 A. Hamada, H. Miyano, H. Watanabe, and H. Saito Interaction of Imatinib Mesilate with Human P-Glycoprotein J. Pharmacol. Exp. Ther., November 1, 2003; 307(2): 824 - 828. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
T. Kamio, T. Toki, R. Kanezaki, S. Sasaki, S. Tandai, K. Terui, D. Ikebe, K. Igarashi, and E. Ito B-cell-specific transcription factor BACH2 modifies the cytotoxic effects of anticancer drugs Blood, November 1, 2003; 102(9): 3317 - 3322. [Abstract] [Full Text] [PDF]
|
|
|
|
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Y. Canitrot, R. Falinski, T. Louat, G. Laurent, C. Cazaux, J.-S. Hoffmann, D. Lautier, and T. Skorski p210 BCR/ABL kinase regulates nucleotide excision repair (NER) and resistance to UV radiation Blood, October 1, 2003; 102(7): 2632 - 2637. [Abstract] [Full Text] [PDF]
|
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 T. Tauchi, M. Sumi, A. Nakajima, G. Sashida, T. Shimamoto, and K. Ohyashiki BCL-2 Antisense Oligonucleotide Genasense Is Active against Imatinib-resistant BCR-ABL-positive Cells Clin. Cancer Res., September 15, 2003; 9(11): 4267 - 4273. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
J. Kuroda, S. Kimura, H. Segawa, Y. Kobayashi, T. Yoshikawa, Y. Urasaki, T. Ueda, F. Enjo, H. Tokuda, O. G. Ottmann, et al. The third-generation bisphosphonate zoledronate synergistically augments the anti-Ph+ leukemia activity of imatinib mesylate Blood, September 15, 2003; 102(6): 2229 - 2235. [Abstract] [Full Text] [PDF]
|
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 M. W. N. Deininger and B. J. Druker Specific Targeted Therapy of Chronic Myelogenous Leukemia with Imatinib Pharmacol. Rev., September 1, 2003; 55(3): 401 - 423. [Abstract] [Full Text] [PDF]
|
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 E. F. Petricoin and L. A. Liotta Clinical Applications of Proteomics J. Nutr., July 1, 2003; 133(7): 2476S - 2484. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
T. Lange, C. Gunther, T. Kohler, R. Krahl, S. Musiol, S. Leiblein, H.-K. Al-Ali, I. van Hoomissen, D. Niederwieser, and M. W. N. Deininger High levels of BAX, low levels of MRP-1, and high platelets are independent predictors of response to imatinib in myeloid blast crisis of CML Blood, March 15, 2003; 101(6): 2152 - 2155. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 K. Peggs and S. Mackinnon Imatinib Mesylate -- The New Gold Standard for Treatment of Chronic Myeloid Leukemia N. Engl. J. Med., March 13, 2003; 348(11): 1048 - 1050. [Full Text] [PDF]
|
|
|
|
 |
|
 A. Nakajima, T. Tauchi, M. Sumi, W. R. Bishop, and K. Ohyashiki Efficacy of SCH66336, a Farnesyl Transferase Inhibitor, in Conjunction with Imatinib against BCR-ABL-positive Cells Mol. Cancer Ther., March 1, 2003; 2(3): 219 - 224. [Abstract] [Full Text] [PDF]
|
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M. Huang, Y. Wang, S. B. Cogut, B. S. Mitchell, and L. M. Graves Inhibition of Nucleoside Transport by Protein Kinase Inhibitors J. Pharmacol. Exp. Ther., February 1, 2003; 304(2): 753 - 760. [Abstract] [Full Text] [PDF]
|
|
|
|
|
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U. J. Scheuring, H. Pfeifer, B. Wassmann, P. Bruck, J. Atta, E. K. Petershofen, B. Gehrke, H. Gschaidmeier, D. Hoelzer, and O. G. Ottmann Early minimal residual disease (MRD) analysis during treatment of Philadelphia chromosome/Bcr-Abl-positive acute lymphoblastic leukemia with the Abl-tyrosine kinase inhibitor imatinib (STI571) Blood, January 1, 2003; 101(1): 85 - 90. [Abstract] [Full Text] [PDF]
|
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|
|
 |
|
 R. Nimmanapalli, E. O'Bryan, M. Huang, P. Bali, P. K. Burnette, T. Loughran, J. Tepperberg, R. Jove, and K. Bhalla Molecular Characterization and Sensitivity of STI-571 (Imatinib Mesylate, Gleevec)-resistant, Bcr-Abl-positive, Human Acute Leukemia Cells to SRC Kinase Inhibitor PD180970 and 17-Allylamino-17-demethoxygeldanamycin Cancer Res., October 15, 2002; 62(20): 5761 - 5769. [Abstract] [Full Text] [PDF]
|
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O. G. Ottmann, B. J. Druker, C. L. Sawyers, J. M. Goldman, J. Reiffers, R. T. Silver, S. Tura, T. Fischer, M. W. Deininger, C. A. Schiffer, et al. A phase 2 study of imatinib in patients with relapsed or refractory Philadelphia chromosome-positive acute lymphoid leukemias Blood, August 28, 2002; 100(6): 1965 - 1971. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
A. F. List, K. J. Kopecky, C. L. Willman, D. R. Head, M. L. Slovak, D. Douer, S. R. Dakhil, and F. R. Appelbaum Cyclosporine inhibition of P-glycoprotein in chronic myeloid leukemia blast phase Blood, August 13, 2002; 100(5): 1910 - 1912. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
A. B. Dash, I. R. Williams, J. L. Kutok, M. H. Tomasson, E. Anastasiadou, K. Lindahl, S. Li, R. A. Van Etten, J. Borrow, D. Housman, et al. A murine model of CML blast crisis induced by cooperation between BCR/ABL and NUP98/HOXA9 PNAS, May 28, 2002; 99(11): 7622 - 7627. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 M. O'Dwyer Multifaceted Approach to the Treatment of Bcr-Abl-Positive Leukemias Oncologist, April 1, 2002; 7(90001): 30 - 38. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 S. Fruehauf, K. Srbic, R. Seggewiss, J. Topaly, and A. D. Ho Functional characterization of podia formation in normal and malignant hematopoietic cells J. Leukoc. Biol., March 1, 2002; 71(3): 425 - 432. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
D. G. Savage and K. H. Antman Imatinib Mesylate -- A New Oral Targeted Therapy N. Engl. J. Med., February 28, 2002; 346(9): 683 - 693. [Full Text] [PDF]
|
|
|
|
|
|
B. M. F. Mow, J. Chandra, P. A. Svingen, C. G. Hallgren, E. Weisberg, T. J. Kottke, V. L. Narayanan, M. R. Litzow, J. D. Griffin, E. A. Sausville, et al. Effects of the Bcr/abl kinase inhibitors STI571 and adaphostin (NSC 680410) on chronic myelogenous leukemia cells in vitro Blood, January 15, 2002; 99(2): 664 - 671. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 M. J. Mauro, M. O'Dwyer, M. C. Heinrich, and B. J. Druker STI571: A Paradigm of New Agents for Cancer Therapeutics J. Clin. Oncol., January 1, 2002; 20(1): 325 - 334. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
C. Yu, G. Krystal, L. Varticovksi, R. McKinstry, M. Rahmani, P. Dent, and S. Grant Pharmacologic Mitogen-activated Protein/Extracellular Signal-regulated Kinase Kinase/Mitogen-activated Protein Kinase Inhibitors Interact Synergistically with STI571 to Induce Apoptosis in Bcr/Abl-expressing Human Leukemia Cells Cancer Res., January 1, 2002; 62(1): 188 - 199. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 B. J. Druker, S. G. O'Brien, J. Cortes, and J. Radich Chronic Myelogenous Leukemia Hematology, January 1, 2002; 2002(1): 111 - 135. [Abstract] [Full Text]
|
|
|
|
|
|
S. M. Graham, H. G. Jorgensen, E. Allan, C. Pearson, M. J. Alcorn, L. Richmond, and T. L. Holyoake Primitive, quiescent, Philadelphia-positive stem cells from patients with chronic myeloid leukemia are insensitive to STI571 in vitro Blood, January 1, 2002; 99(1): 319 - 325. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
Y. A. Elsayed and E. A. Sausville Selected Novel Anticancer Treatments Targeting Cell Signaling Proteins Oncologist, December 1, 2001; 6(6): 517 - 537. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
N. C. Wolff and R. L. Ilaria Jr Establishment of a murine model for therapy-treated chronic myelogenous leukemia using the tyrosine kinase inhibitor STI571 Blood, November 1, 2001; 98(9): 2808 - 2816. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
S. P. Whitman, K. J. Archer, L. Feng, C. Baldus, B. Becknell, B. D. Carlson, A. J. Carroll, K. Mrozek, J. W. Vardiman, S. L. George, et al. Absence of the Wild-Type Allele Predicts Poor Prognosis in Adult de Novo Acute Myeloid Leukemia with Normal Cytogenetics and the Internal Tandem Duplication of FLT3: A Cancer and Leukemia Group B Study Cancer Res., October 1, 2001; 61(19): 7233 - 7239. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 R. M. Kisabeth Laboratory Adaptations--Changing Expectations Clin. Chem., August 1, 2001; 47(8): 1509 - 1515. [Full Text] [PDF]
|
|
|
|
|
|
W. Zhang, P. M. Laborde, K. R. Coombes, D. A. Berry, and S. R. Hamilton Cancer Genomics: Promises and Complexities Clin. Cancer Res., August 1, 2001; 7(8): 2159 - 2167. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
B. A. Chabner The Oncologic Four-Minute Mile Oncologist, June 1, 2001; 6(3): 230 - 232. [Full Text] [PDF]
|
|
|
|
|
|
M. J. Mauro and B. J. Druker STI571: Targeting BCR-ABL as Therapy for CML Oncologist, June 1, 2001; 6(3): 233 - 238. [Abstract] [Full Text] [PDF]
|
|
|
|
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B. J. Druker, C. L. Sawyers, H. Kantarjian, D. J. Resta, S. F. Reese, J. M. Ford, R. Capdeville, and M. Talpaz Activity of a Specific Inhibitor of the BCR-ABL Tyrosine Kinase in the Blast Crisis of Chronic Myeloid Leukemia and Acute Lymphoblastic Leukemia with the Philadelphia Chromosome N. Engl. J. Med., April 5, 2001; 344(14): 1038 - 1042. [Abstract] [Full Text] [PDF]
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B. J. Druker, C. L. Sawyers, R. Capdeville, J. M. Ford, M. Baccarani, and J. M. Goldman Chronic Myelogenous Leukemia Hematology, January 1, 2001; 2001(1): 87 - 112. [Abstract] [Full Text] [PDF]
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Top
Abstract
Introduction
(Schering, Kenilworth,
NJ), Ara-C (Pharmacia & Upjohn, Kalamazoo, MI), and HU (Sigma, St
Louis, MO) were dissolved in sterile water, diluted in RPMI-1640 medium
(Gibco BRL, Rockville, MD), and used within 24 hours of reconstitution.
3-(4,5-Dimethylthiazole-2-yl)-2,5-diphenyltetrazolium bromide
(MTT) (Sigma) was stored as a 10 mg/mL sterile stock solution and used at a final concentration of 1 mg/mL.
) to each antileukemic
agent with 0.05 µmol/L STI571 (
). Each data point represents a
mean across 4 identical wells from 1 of 3 separate experiments.
Standard deviations ranged from ± 0% to 13%, with a median of
2%. Regression lines generated in Microsoft Excel represent the best
fit relationship between drug concentration and the percentage of
inhibition of proliferation. R2 values indicate the
percentage of data that can be accounted for by the regression line.
IC60 concentrations for the MO7p210 with each antileukemic alone and in
combination with STI571 were determined from these graphs and are
listed in Table 
