![[Feedback]](/icons/banner/feedbackACT.gif){kind=icon}
![[For Subscribers]](/icons/banner/subscriberACT.gif){kind=icon}
![[Archive]](/icons/banner/archiveACT.gif){kind=icon}
![[Search]](/icons/banner/searchACT.gif){kind=icon}
![[Contents]](/icons/banner/tocACT.gif){kind=icon}
|
|
|
|
|
||
Vol. 52, Issue 6, 1000-1009, 1997
-D-Arabinofuranosylcytosine-Induced
Apoptosis in Human Leukemia Cells that Overexpress Bcl-2
Departments of
Medicine (S.W., J.A.V., T.M.B., A.J.F.,
W.D.J., L.B.K., G.K.),
Radiation Oncology (P.D.),
Pharmacology and
Toxicology (P.D., S.G.), and
Microbiology and Immunology (G.K., S.G.),
Medical College of Virginia, Richmond, Virginia 23298
The effects of the non-tumor-promoting protein kinase C (PKC) activator
bryostatin 1 and the PKC inhibitors staurosporine and UCN-01 were
examined with respect to modulation of
1-[
-D-arabinofuranosyl]cytosine (ara-C)-induced
apoptosis in human myeloid leukemia cells (HL-60) overexpressing the
antiapoptotic protein Bcl-2. HL-60/Bcl-2 cells displayed a 5-fold
increase in Bcl-2 protein compared with empty-vector counterparts
(HL-60/pCEP4) but comparable levels of Bax, Mcl-1, and
Bcl-xL. After exposure to an equimolar concentration of
ara-C (10 µM for 6 hr), HL-60/Bcl-2 cells were
significantly less susceptible to apoptosis, DNA fragmentation, and
loss of clonogenicity than HL-60/pCEP4 cells. The protective effect of
increased Bcl-2 expression was manifested by a failure of ara-C to
induce activation/cleavage of the Yama protease (CPP32; caspase-3) and
degradation of one of its substrates, poly(ADP-ribose)polymerase to an
85-kDa cleavage product. When HL-60/Bcl-2 cells were preincubated with
bryostatin 1 (10 nM; 24 hr) or coincubated with either
staurosporine (50 nM; 6 hr) or UCN-01 (300 nM;
6 hr) after a 1-hr preincubation, exposures that exerted minimal
effects alone, ara-C-induced apoptosis and DNA fragmentation were
restored to levels equivalent to, or greater than, those observed in
empty-vector controls. These events were accompanied by restoration of
the ability of ara-C to induce CPP32 cleavage and activation,
poly(ADP-ribose) polymerase degradation, and inhibition of colony
formation. Western analysis of Bcl-2 protein obtained from
overexpressing cells treated with bryostatin 1, staurosporine, or
UCN-01 revealed the appearance of a slowly migrating species and a
general broadening of the protein band, effects that were insensitive
to the protein synthesis inhibitor cycloheximide. Alterations in Bcl-2
protein mobility on sodium dodecyl sulfate-polyacrylamide gel
electrophoresis were reversed by treatment of lysates with alkaline
phosphatase or protein phosphatase 2A; actions of the latter were
blocked by the specific phosphatase inhibitor okadaic acid. In
vivo labeling studies of Bcl-2 protein demonstrated
increased incorporation of
[32PO4]orthophosphate in drug-treated cells.
Last, phosphorylated Bcl-2 failed to display decreased binding to the
proapoptotic protein Bax. Collectively, these findings indicate that
bryostatin 1, which down-regulates PKC, and staurosporine and UCN-01,
which directly inhibit the enzyme, circumvent resistance of
Bcl-2-overexpressing leukemic cells to ara-C-induced apoptosis and
activation of the protease cascade. They also raise the possibility
that modulation of Bcl-2 phosphorylation status contributes to this
effect.
This article has been cited by other articles:
|
|
 |
|
  C. A. Granville, R. M. Memmott, J. J. Gills, and P. A. Dennis Handicapping the Race to Develop Inhibitors of the Phosphoinositide 3-Kinase/Akt/Mammalian Target of Rapamycin Pathway Clin. Cancer Res., February 1, 2006; 12(3): 679 - 689. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 G. Dasmahapatra, J. A. Almenara, and S. Grant Flavopiridol and Histone Deacetylase Inhibitors Promote Mitochondrial Injury and Cell Death in Human Leukemia Cells That Overexpress Bcl-2 Mol. Pharmacol., January 1, 2006; 69(1): 288 - 298. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
L. M. Karnitz, K. S. Flatten, J. M. Wagner, D. Loegering, J. S. Hackbarth, S. J. H. Arlander, B. T. Vroman, M. B. Thomas, Y.-U. Baek, K. M. Hopkins, et al. Gemcitabine-Induced Activation of Checkpoint Signaling Pathways That Affect Tumor Cell Survival Mol. Pharmacol., December 1, 2005; 68(6): 1636 - 1644. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 R. R. Rosato, J. A. Almenara, S. C. Maggio, P. Atadja, R. Craig, J. Vrana, P. Dent, and S. Grant Potentiation of the lethality of the histone deacetylase inhibitor LAQ824 by the cyclin-dependent kinase inhibitor roscovitine in human leukemia cells Mol. Cancer Ther., November 1, 2005; 4(11): 1772 - 1785. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
S. Grant and P. Dent Kinase Inhibitors and Cytotoxic Drug Resistance Clin. Cancer Res., April 1, 2004; 10(7): 2205 - 2207. [Full Text] [PDF]
|
|
|
|
 |
|
 W. Jia, C. Yu, M. Rahmani, G. Krystal, E. A. Sausville, P. Dent, and S. Grant Synergistic antileukemic interactions between 17-AAG and UCN-01 involve interruption of RAF/MEK- and AKT-related pathways Blood, September 1, 2003; 102(5): 1824 - 1832. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 R. R. Rosato, J. A. Almenara, and S. Grant The Histone Deacetylase Inhibitor MS-275 Promotes Differentiation or Apoptosis in Human Leukemia Cells through a Process Regulated by Generation of Reactive Oxygen Species and Induction of p21CIP1/WAF1 1 Cancer Res., July 1, 2003; 63(13): 3637 - 3645. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
S. Wang, Z. Wang, P. Dent, and S. Grant Induction of tumor necrosis factor by bryostatin 1 is involved in synergistic interactions with paclitaxel in human myeloid leukemia cells Blood, May 1, 2003; 101(9): 3648 - 3657. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
L. Cartee, S. C. Maggio, R. Smith, H. M. Sankala, P. Dent, and S. Grant Protein Kinase C-dependent Activation of the Tumor Necrosis Factor Receptor-mediated Extrinsic Cell Death Pathway Underlies Enhanced Apoptosis in Human Myeloid Leukemia Cells Exposed to Bryostatin 1 and Flavopiridol Mol. Cancer Ther., January 1, 2003; 2(1): 83 - 93. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
S. Wang, Z. Wang, and S. Grant Bryostatin 1 and UCN-01 Potentiate 1-beta -D-Arabinofuranosylcytosine-Induced Apoptosis in Human Myeloid Leukemia Cells through Disparate Mechanisms Mol. Pharmacol., January 1, 2003; 63(1): 232 - 242. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
L. H. Cragg, M. Andreeff, E. Feldman, J. Roberts, A. Murgo, M. Winning, M. B. Tombes, G. Roboz, L. Kramer, and S. Grant Phase I Trial and Correlative Laboratory Studies of Bryostatin 1 (NSC 339555) and High-Dose 1-B-D-Arabinofuranosylcytosine in Patients with Refractory Acute Leukemia Clin. Cancer Res., July 1, 2002; 8(7): 2123 - 2133. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 Z. Wang, S. Wang, Y. Dai, and S. Grant Bryostatin 1 Increases 1-beta -D-Arabinofuranosylcytosine-Induced Cytochrome c Release and Apoptosis in Human Leukemia Cells Ectopically Expressing Bcl-xL J. Pharmacol. Exp. Ther., May 1, 2002; 301(2): 568 - 577. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
C. M. Barrett, F. L. Lewis, J. B. Roaten, T. W. Sweatman, M. Israel, J. L. Cleveland, and L. Lothstein Novel Extranuclear-targeted Anthracyclines Override the Antiapoptotic Functions of Bcl-2 and Target Protein Kinase C Pathways to Induce Apoptosis Mol. Cancer Ther., May 1, 2002; 1(7): 469 - 481. [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]
|
|
|
|
|
|
Y. Dai, C. Yu, V. Singh, L. Tang, Z. Wang, R. McInistry, P. Dent, and S. Grant Pharmacological Inhibitors of the Mitogen-activated Protein Kinase (MAPK) Kinase/MAPK Cascade Interact Synergistically with UCN-01 to Induce Mitochondrial Dysfunction and Apoptosis in Human Leukemia Cells Cancer Res., July 1, 2001; 61(13): 5106 - 5115. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
C. Yu, S. Wang, P. Dent, and S. Grant Sequence-Dependent Potentiation of Paclitaxel-Mediated Apoptosis in Human Leukemia Cells by Inhibitors of the Mitogen-Activated Protein Kinase Kinase/Mitogen-Activated Protein Kinase Pathway Mol. Pharmacol., July 1, 2001; 60(1): 143 - 154. [Abstract] [Full Text]
|
|
|
|
|
|
P. Dent and S. Grant Pharmacologic Interruption of the Mitogen-activated Extracellular-regulated Kinase/Mitogen-activated Protein Kinase Signal Transduction Pathway: Potential Role in PromotingCytotoxic Drug Action Clin. Cancer Res., April 1, 2001; 7(4): 775 - 783. [Full Text]
|
|
|
|
|
|
L. Cartee, Z. Wang, R. H. Decker, S. P. Chellappan, G. Fusaro, K. G. Hirsch, H. M. Sankala, P. Dent, and S. Grant The Cyclin-dependent Kinase Inhibitor (CDKI) Flavopiridol Disrupts Phorbol 12-Myristate 13-Acetate-induced Differentiation and CDKI Expression while Enhancing Apoptosis in Human Myeloid Leukemia Cells Cancer Res., March 1, 2001; 61(6): 2583 - 2591. [Abstract] [Full Text]
|
|
|
|
|
|
S. Harvey, R. Decker, Y. Dai, G. Schaefer, L. Tang, L. Kramer, P. Dent, and S. Grant Interactions between 2-Fluoroadenine 9-{beta}-D-Arabinofuranoside and the Kinase Inhibitor UCN-01 in Human Leukemia and Lymphoma Cells Clin. Cancer Res., February 1, 2001; 7(2): 320 - 330. [Abstract] [Full Text]
|
|
|
|
|
|
W. D. Jarvis, F. A. Fornari Jr., R. M. Tombes, R. K. Erukulla, R. Bittman, G. K. Schwartz, P. Dent, and S. Grant Evidence for Involvement of Mitogen-Activated Protein Kinase, Rather than Stress-Activated Protein Kinase, in Potentiation of 1-beta -D-Arabinofuranosylcytosine-Induced Apoptosis by Interruption of Protein Kinase C Signaling Mol. Pharmacol., November 1, 1998; 54(5): 844 - 856. [Abstract] [Full Text]
|
|
 |
 |
 |
|
 |
 |
 |
