Examples of Acute Leukemia

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Examples of Acute Leukemia
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FISH
t(821)
normal
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The t(1418)
How is Bcl-2 Regulated Normally? Expression is
regulated Function is regulated by    
phosphorylation     interaction with other
proteins eg Bad Bad can also be regulated    
by phosphorylation What goes wrong in cancer?
Bcl-2 is overexpressed (translocation,
mutation) Normal apoptosis (eg due to growth
factor withdrawal) is reduced Apoptosis
induced by damage is reduced Cells survive with
damaged DNA Risk of mutation increased
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The t(814)
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Nature 1973 Jun 1243(5405)290-3 Related
Articles, Books, OMIM, LinkOut Letter A new
consistent chromosomal abnormality in chronic
myelogenous leukaemia identified by quinacrine
fluorescence and Giemsa staining. Rowley JD.
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Normal Peripheral Blood
Normal Bone Marrow
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CML
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Chronic Myelogenous Leukemia Peripheral Blood.
Wright's Stain. Oil Immersion (x100) Note the
high concentration of leukocytes. (A)
Myeloblasts. (B) Neutrophilic Myelocyte. (C)
Neutrophilic Metamyelocyte. (D) Band neutrophil.
(E) Basophil.
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BCR/ABL
STI-571

• Increased survival
• Increased proliferation

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Acute Promyelocytic Leukemia (APL) - FAB M3
t(1517) PML-RARa Maturation In the classic M3
the majority of the proliferating cells are
abnormal promyelocytes with numerous primary type
granules. Auer rods are frequent and often
multiple. Staining The cells are MPO and
chloroacetate esterase (CAE) positive, but
generally negative for NSE (NSE positive in
25). Immunophenotype Positivity for CD13 and
CD33, but are usually negative for HLA-DR
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Blood 1988 Aug72(2)567-72 Related Articles,
Books Use of all-trans retinoic acid in the
treatment of acute promyelocytic leukemia. Huang
ME, Ye YC, Chen SR, Chai JR, Lu JX, Zhoa L, Gu
LJ, Wang ZY. Shanghai Institute of Hematology,
Shanghai Second Medical University, People's
Republic of China. Twenty-four patients with
acute promyelocytic leukemia (APL) were treated
with all-trans retinoic acid (45 to 100
mg/m2/day). Of these, eight cases had been either
nonresponsive or resistant to previous
chemotherapy the other 16 cases were previously
untreated. All patients attained complete
remission without developing bone marrow
hypoplasia. Bone marrow suspension cultures were
studied in 15 of the 24 patients. Fourteen of
these patients had morphological maturation in
response to the retinoic acid (1 mumol/L).
Chloroacetate esterase and alpha-naphthyl acetate
esterase staining as well as electronmicroscopic
examination confirmed that retinoic acid-induced
cells differentiated to granulocytes with
increased functional maturation (as measured by
nitroblue tetrazolium reduction, NBT). The single
nonresponder to retinoic acid in vitro was
resistant to treatment with retinoic acid but
attained complete remission after addition of
low-dose cytosine arabinoside (ara-C). During the
course of therapy, none of the patients showed
any abnormalities in the coagulation parameters
we measured, suggesting an absence of any
subclinical disseminated intravascular
coagulation. The only side effects consisted of
mild dryness of the lips and skin, with
occasional headaches and digestive symptoms.
Eight patients have relapsed after 2 to 5 months
of complete remission. The others remain in
complete remission at 1 to 11 months and are
still being followed up. We conclude that
all-trans retinoic acid is an effective inducer
for attaining complete remission in APL.
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Molecular analysis of acute promyelocytic
leukemia breakpoint cluster region on chromosome
17. Borrow J, Goddard AD, Sheer D, Solomon
E Science. 1990 Sep 28249(4976)1577-80. Medline
91019420   The t(1517) translocation of acute
promyelocytic leukaemia fuses the retinoic acid
receptor alpha gene to a novel transcribed
locus. de The H, Chomienne C, Lanotte M, Degos L,
Dejean A Nature. 1990 Oct 11347(6293)558-61. Med
line 91015360   Translocation breakpoint of acute
promyelocytic leukemia lies within the retinoic
acid receptor alpha locus. Alcalay M, Zangrilli
D, Pandolfi PP, Longo L, Mencarelli A, Giacomucci
A, Rocchi M, Biondi A, Rambaldi A, Lo Coco F, et
al Proc Natl Acad Sci U S A. 1991 Mar
188(5)1977-81. Medline 91156729
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A
Histone Deacetylases
N-CoR/ SMRT
Histone Acetyltranserases
mSin3A
RA
X
RAR?
RAR?
B
N-CoR/ SMRT
Histone Deacetylases
N-CoR/ SMRT
Histone Deacetylases
mSin3A
high levels ATRA
N-CoR/ SMRT
mSin3A
X
PML/RAR?
PML/RAR?
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Blood 1996 Aug 188(3)1052-61 Related Articles,
Books In vitro studies on cellular and
molecular mechanisms of arsenic trioxide (As2O3)
in the treatment of acute promyelocytic leukemia
As2O3 induces NB4 cell apoptosis with
downregulation of Bcl-2 expression and modulation
of PML-RAR alpha/PML proteins. Chen GQ, Zhu J,
Shi XG, Ni JH, Zhong HJ, Si GY, Jin XL, Tang W,
Li XS, Xong SM, Shen ZX, Sun GL, Ma J, Zhang P,
Zhang TD, Gazin C, Naoe T, Chen SJ, Wang ZY, Chen
Z. Shanghai Institute of Hematology, Rui-Jin
Hospital, Department of Biophysics, Shanghai
Second Medical University, P.R. China. It has
been shown recently in China that arsenic
trioxide (As2O3) is a very effective treatment
for acute promyelocytic leukemia (APL). APL
patients resistant to all-trans retinoic acid
(ATRA) and conventional chemotherapy can still
respond to AS2O3. In this study, we addressed the
possible cellular and molecular mechanisms of
this treatment by using NB4 cells as a model. The
results show that (1) As2O3 triggers relatively
specific NB4 cell apoptosis at micromolar
concentration, as proved by morphology,
histogramic related nuclear DNA contents, and DNA
gel eletrophoresis. (2) As2O3 does not influence
bax, bcl-x, c-myc, and p53 gene expression, but
downregulates bcl-2 gene expression at both mRNA
and protein levels. (3) As2O3 induces a
significant modulation of the PML staining
pattern in NB4 cells and HL-60 cells. The
micropunctates characteristic of PML-RAR alpha in
NB4 cells dissappear after treatment with As2O3,
whereas a diffuse PML staining occurs in the
perinuclear cytoplasmic region. In addition, a
low percentage of untreated NB4 cells exhibits an
accumulation of PML positive particles in a
compartment of cytoplasm. The percentage of these
cells can be significantly increased after As2O3
treatment. A similar PML staining pattern is
observed in apoptotic cells. (4) ATRA
pretreatment does not influence As2O3-induced
apoptosis. These results suggest that induction
of cell apoptosis can be one of the mechanisms of
the therapeutic effect of As2O3. Moreover, this
apoptosis induction occurs independently of the
retinoid pathway and may be mediated, at least
partly, through the modulation of bcl-2, as well
as PML-RAR alpha and/ or PML proteins.
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t(821) AML-1/ETO 10-15 t(1621) AML-1/MTG16
t(1221) TEL/AML-1 25 (B-ALL)
Inv (16) CBFß/MYH11 8
CBF-ß
AML-1B (CBF-?)
p14ARF
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AML with differentiation (M2) Myeloblasts with
some maturation beyond the promyelocyte rare
thin Auer rods present. Translocation t(821)
(q22q22), common to M2, involves ETO and AML1
genes, respectively. Arrows show breakpoints in
chromosomes 8 and 21. This translocation is
associated with a favorable prognosis.
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The t(821) creates the AML-1/ETO fusion protein
AML-1
RHD
TAF110
HHR
ZF
ND
ETO
TAF110
HHR
ZF
ND
RHD
AML/ETO
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Activator
AML-1B
HDAC
mSin3
N-CoR/ SMRT
ETO
HDAC
mSin3
N-CoR/ SMRT
X
AML-1/ETO
Target Genes
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Inv(16)
CBFß
MHY11
C-C
CBFß
MHY11
C-C
inv(16)(p13q22)
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The inv(16) fusion protein acts as an AML-1
co-repressor
Histone Deacetylases?
mSin3A
Inv (16) CBFß/SMMHC
X
AML-1
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t(1221)
ETS
TEL/ETV6
AML-1
RHD
TEL
AML-1
RHD
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mSin3
mSin3
TEL
AML-1B
HDAC3
HDAC3
N-CoR
mSin3
X
TEL/AML-1B
Target Genes
TGT/c GGT ACA/g CCA
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Fusion Proteins
Onco. e.g. Ras
Immortalization Hyperproliferation
p14
X
p53
MDM2
Cellular Proliferation
Molecular Model of Leukemogenesis