| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
|
|
|
|||||||
|
|||||||||
* Department of Immunology and Oncology, Centro Nacional de Biotecnología/CSIC, Universidad Autonóma de Madrid, Cantoblanco, Madrid E-28049;
Hospital Ramón y Cajal, Carretera de Colmenar Km 9, Madrid E-28034;
Department of Animal Pathology, Veterinary School, Universidad Complutense de Madrid, Madrid E-28040; and
§ Centro de Biología Molecular/CSIC, Universidad Autónoma de Madrid, Cantoblanco, Madrid E-28049, Spain
1Correspondence: Centro Nacional de Biotecnología, Carretera de Colmenar Km 16, Cantoblanco, Madrid E-28049, Spain. E-mail: acarrera{at}cnb.uam.es
 |
ABSTRACT |
|---|
 TOP ABSTRACT INTRODUCTIONMATERIALS AND METHODSRESULTSDISCUSSIONREFERENCES |
|---|
Key Words: lymphoproliferative disease • autoimmunity • cancer • phosphoinositide 3-kinase • PTEN
|
INTRODUCTION |
|---|
|
TOPABSTRACTINTRODUCTIONMATERIALS AND METHODSRESULTSDISCUSSIONREFERENCES |
|---|
, 2
). The in vivo role of 3-phosphoinositides is
nonetheless poorly understood. Knockout mice for the PI3K p85
isoform revealed an essential role for this isoform in B cells
(3
, 4)
. Other PI3K isoforms are retained in these mice,
however, and the observation that T cell proliferation is blocked after
inhibition of PI3K activity suggests that other isoforms (such as
p85ß) may replace p85 function in T cells (3)
. PI3K
has also been implicated in tumor formation based on the increased copy
number of 3q26, a region that includes the p110 catalytic subunit,
in ~40% of ovarian tumors (5)
. In addition, the tumor
suppressor phosphatase PTEN, mutated in a large proportion of human
tumors, down-regulates PI3K pathways (6
7
8)
. Nonetheless,
selective impairment of 3-phosphoinositide recognition has been
described in only one naturally occurring human PTEN mutation (9
, 10)
; it remains unclear whether other substrates of this
phosphatase, such as Shc and focal adhesion kinase
(11
12
13)
, are essential mediators of this tumor
suppressor.
To elucidate PI3K involvement in T cell function and to establish the
role of deregulated PI3K in tumor formation, we generated transgenic
mice expressing an active PI3K form in T cells. The allele used,
p65PI3K, a truncation mutant of p85 isolated
from a thymic lymphoma, associates with p110 and drives its
constitutive activation, resulting in the induction of downstream PI3K
effectors such as AKT and rac (14)
. We show that
expression of this active PI3K form in T lymphocytes induces cell
survival in vivo, resulting in the development of an
infiltrating lymphoproliferative disorder and autoimmmune renal disease
similar to that developed by a heterozygous
PTEN+/- mice (15)
. Moreover, PTEN
selectively blocks PI3K-induced focus formation, but not v-src- or
v-raf-induced foci. Finally, we show that p65PI3K
expression predisposes to tumor formation in vivo. Together,
these results demonstrate the relevance of PI3K in T cell homeostasis
and its contribution to tumor formation, and suggest that
3-phosphoinositides are the most important PTEN substrates for its
tumor suppressor function.
|
MATERIALS AND METHODS |
|---|
|
TOPABSTRACTINTRODUCTIONMATERIALS AND METHODSRESULTSDISCUSSIONREFERENCES |
|---|
into the
BamHI site of the p56 Lck promotor (pLck) human growth
hormone (hGh) vector (16)
. The purified NotI
fragment containing the pLck-p65PI3K-hGH
transgene was injected into the pronuclei of fertilized oocytes of
(C57BL/6 x CBA) F1 mice. Microinjected eggs were
transferred into pseudo-pregnant F1 recipients.
Offspring were analyzed 30 days after birth by polymerase chain
reaction (PCR) and Southern blot analysis, and four transgene-positive
lines were backcrossed onto the C57BL/6 background for subsequent
experiments. p65PI3K Tg mice were crossed with
p53-/- or p53+/- mice
(17)
to obtain the different genotype mice used in tumor
formation experiments. All animals were PCR-screened using specific
primers. Mice were bred and maintained under specific pathogen-free
conditions at the Centro Nacional de Biotecnología.
Histology
Mice were examined twice weekly for the appearance of tumors or
other clinical signs; affected mice or controls were killed, and tumor
and organs were collected for histology or flow cytometry analysis.
Tissues were fixed in phosphate-buffered saline (PBS) -buffered 10%
formalin, processed, paraffin-embedded, and hematoxylin/eosin stained
using standard techniques. For immunohistochemistry, fresh organs were
included in standard tissue freezing solution (Jung, Nussloch,
Germany). Frozen kidney sections were fixed with cold acetone and
blocked with an avidin/biotin blocking kit (Vector, Burlingame, Calif.)
for biotinylated anti-CD3 staining (145–2C11; PharMingen, San Diego,
Calif.), or blocked in PBS with 10% fetal calf serum and 2% bovine
serum albumin for fluorescein isothiocyanate (FITC) -conjugated goat
anti-mouse immunoglobulin G (IgG) staining (PharMingen). Biotinylated
anti-CD3-stained sections were developed with streptavidin-peroxidase
(Dako, Glostrup, Denmark). Finally, sections were hematoxylin stained.
Flow cytometry, cell death analysis, and focus
formation
Cell suspensions from thymus, spleen, and lymph nodes were
prepared by grinding tissue through sterile wire mesh. In some assays,
lymphocyte subpopulations were purified using Cellect columns (Biotex,
Alberta, Canada). For cell surface staining, all antibodies (Abs) used
were conjugated to FITC, phycoerythrin, or biotin. Biotinylated Abs
were developed with streptavidin-SPRD (Southern Biotechnology,
Birmingham, Ala.). The following Abs from PharMingen were used: CD8
(Ly-2, 53–6,7), CD4 (L3T4, H129.19), CD3 (145–2C11), CD11b (
chain, M1/70), B220 (CD45R, RA3–6B2), CD44 (pgp1, IM7), and CD62L
(Mel-14). CD45RB (C363.16A) was from Southern Biotechnology, the
annexin V-FITC kit was from Coulter Immunotech (Miami, Fla.), and
labeling was performed according to manufacturer’s instructions. Cells
were analyzed on an EPICS XL using system II software (Coulter). DNA
content estimation, in vitro culture, and anti-Fas
Ab-induced cell death were performed as described (18)
.
Cell viability was determined by trypan blue exclusion. CD4+ or CD8+
cell number was estimated in flow cytometry analysis as the proportion
of each subset at each time point. Focus formation assays were
performed as described (14)
. hPTEN cDNA was amplified from
poly(A)-mRNA of MCF-7 cells and was subcloned in pRK5.
Biochemical and serological analyses
Cell lysis, immunoprecipitation, phospholipid in
vitro kinase assays, AKT assays, and Western blotting were
performed as described (14)
. Anti-AKT Ab was from Upstate
Biotechnology (Lake Placid, N.Y.). Anti-PTEN Ab was from Santa Cruz
Biotechnology (Santa Cruz, Calif.). Serum Ig measurement was performed
as described (19)
. The titer represents the serum dilution
yielding an A492 equal to half-maximal binding
activity of a wild-type (WT) mouse serum pool. Isotype-specific
anti-dsDNA measurement and relative autoantibody unit calculation were
performed as described (19)
. Since WT mice have low
amounts of IgG autoantibodies, autoantibody unit refers to the amount
of anti-dsDNA IgG2a in a pool of p65PI3K Tg mouse
serum (100 units).
|
RESULTS |
|---|
|
TOPABSTRACTINTRODUCTIONMATERIALS AND METHODSRESULTSDISCUSSIONREFERENCES |
|---|
. Two of these lines contained ten integrated
copies of the transgene (high-copy founders) and two contained two
integrated copies (low-copy founders). Tg females were sterile
(currently under study), and transgenic lines were thus maintained by
crossing Tg males onto a C57BL/6 background. High-copy founders
expressed p65PI3K in thymus at levels similar to
those of endogenous p85 (Fig. 1A
), and were used in subsequent experiments.
p65PI3K was expressed in similar amounts in
purified CD4+ and CD8+ T cells (Fig. 1B, C
), but not in
purified B cells (not shown). As described in vitro
(14)
, p65PI3K associates with the
p110 catalytic subunit, causing increased associated lipid kinase
activity (Fig. 1D
) and activating the PI3K effector AKT
(1)
, particularly in purified mature Tg T cells
(Student’s t test, P=0.008; Fig. 1E
).
|
Peripheral CD4+ T cell accumulation in p65PI3K Tg mice
Six-week-old Tg mice showed a slight increase in spleen CD4+ T
cell number as compared to WT littermates (~30% higher,
P<0.001; Fig. 2A
); no differences were observed in CD8+ T cells, B
lymphocytes (B220+) (Fig. 2A
), 
T cells, or natural
killer cells (not shown). The increase in peripheral CD4+ T cells
persisted in Tg mice for the following 6–10 months. At 8–10 months, a
more marked increase in the CD4+ T cell pool was observed in some mice,
leading to a massive accumulation of CD4+ T cells in 12- to
15-month-old Tg mouse spleen (Fig. 2B
) and lymph node (not
shown). Peripheral B lymphocytes (B220+) and macrophages (CD11b+)
remained essentially unchanged until 12–15 months after birth, when
they also increased in Tg mice (Fig. 2B
). At this age,
lymphoid organs were no longer well structured and spleens showed
marked hyperplasia of the white pulp (Fig. 2C, D
; WT and Tg,
respectively). In addition, these mice showed alterations such as
reduced mobility and skin lesions.
|
Memory markers are up-regulated in CD4+ T cells from
p65PI3K Tg mice
A hallmark of the autoimmune diseases that affect autoimmune-prone
mouse strains is the progressive accumulation of activated T and B
cells in the periphery. We thus compared lineage and activation marker
expression in WT and p65PI3K Tg mouse spleen and
lymph node cells. The fraction of T cells expressing the shared
memory/activated CD44high
CD62Llow CD45RBlow
phenotype (20
, 21)
was increased in Tg mice compared to WT
mice, as a function of age (not shown). Evident increases were observed
in 10-month-old Tg mice (Fig. 2E
) prior to the dramatic
enlargement of the T cell pool. Triple staining analysis confirmed that
the CD44high cells also expressed
CD62Llow and CD45RBlow. To
determine whether these cells represented either fully activated T
lymphocytes or memory T cells, we examined expression of the specific
markers of activated T lymphocytes, CD25, CD54, CD69, CD11b, and VLA-4
(22
, 23)
. Expression of these activation markers was not
significantly increased in CD4+ T cells from
p65PI3K Tg mice between 6 wk and 10 months of
age, suggesting that the CD4+ T cell population in these mice was
enriched in memory cells. In contrast, in the CD8+ pool, only CD44
expression was altered (not shown). CD4+ memory cells accumulated as
lymphoproliferative disease progressed, representing >90% of T cells
at advanced stages of the disease. In some 12- to 15-month-old Tg mice,
the expanding CD4+ cell population acquired a partially activated
phenotype, with increased expression of CD69 and CD54, but not of CD25,
CD11b, or VLA4. CD4+ T lymphocytes also showed an increase in Fas
expression in mice at this age, but no significant changes were
detected in CD8+ T lymphocytes.
Infiltrating lymphoproliferative disorder and autoimmune renal
disease in adult p65PI3K Tg mice
Serial necropsies were performed on 9 WT and 29 Tg mice showing
signs of disease at ages ranging from 12 to 15 months. Transgenic mice
showed large lymphoid infiltrates in nonlymphoid organs including lung,
salivary glands, kidney, ovary, and at advanced disease stages in
liver, heart, gastrointestinal tract, and pancreas. In lung, the organ
with the heaviest mononuclear accumulation, infiltrates were typically
perivascular, with penetration of the vascular wall, showing no signs
of parenchymal destruction (Fig. 3A, B
; WT and Tg, respectively). Flow cytometric
analysis of lung cell suspensions showed that the mononuclear
infiltrate was composed primarily of CD4+ T cells (60%; the remainder
were CD8+T cells, B cells and, in a lower proportion, macrophages).
p65PI3K Tg mouse kidneys also showed heavy
cellular infiltrates (Fig. 3C
), apparently enriched in T
cells (Fig. 3D
), as well as glomerulonephritis in severely
affected animals (see below). The remaining organs also showed
lymphocyte infiltration, with no signs of tissue destruction. Flow
cytometry analysis of T cell receptor Vß chain expression in 10
affected Tg mice indicated that the lymphocytic expansion was
polyclonal (not shown).
|
The appearance of glomerulonephritis in animals with severe
lymphoproliferative disorder suggested immune complex-mediated
autoimmunity. Most 12- to 15-month-old p65PI3K Tg
mice showed polyclonal hypergammaglobulinemia (Fig. 4A
), with marked increases in IgG1 (~50-fold) and moderate
increases in IgG2a (~10-fold). Anti-double-stranded DNA
autoantibodies (dsDNA Ab) were also elevated in the serum of most Tg
mice; these were mainly of the IgG1 (10- to 1000-fold increase) and
IgG2a isotypes (10-fold increase) (Fig. 4B
). IgG1 production
is driven by Th1 cytokines (IL-4) (24)
and, in accordance
with the pronounced increase in IgG1 dsDNA Ab, a large proportion of
12- to 15-month-old Tg mice exhibited increased serum interleukin 4
(IL-4) levels (not shown). Histological comparison of WT and
p65PI3K Tg kidneys (Fig. 4C, D
,
respectively) showed severe mesangioproliferative glomerulonephritis in
Tg mice, with an increase in mesangial matrix, thickened capillary
walls, and obliteration of many capillaries.
p65PI3K Tg mouse kidneys showed granular immune
complexes in immunohistological examination (Fig. 4E
) similar to those observed in MLR-lpr
mice (Fig. 4F
), which were absent in WT controls.
In conclusion, the majority of animals with advanced
lymphoproliferative disease also developed severe autoimmune
glomerulonephritis.
|
The p65PI3K transgene increases T cell survival
Expansion of the CD4+ lymphocyte pool in Tg mice suggested that
p65PI3K augmented cell survival and/or division
rates. To study this, freshly isolated CD4+ and CD8+ cells from young
(6-wk-old) WT and Tg mice were labeled with annexin V (25)
to measure the in vivo cell death rate. Annexin V labeling
was lower in CD4+ cells from Tg mice than in WT controls (not shown).
These differences were more pronounced in Tg mouse CD4+ memory cells
(Fig. 5A
), as CD4+CD44high cells showed
significantly lower annexin V labeling than did WT controls
(P=0.008). No differences were observed between WT and Tg
mice in the CD4+CD44low/int pools, which stained
for annexin V at low levels, or in the CD8+ cell subpopulations. The
expanding CD4+ memory cell population in Tg mice thus exhibits
defective cell death in vivo. Similar results were obtained
when memory cells were selected according to
CD4+CD62Llow expression.
|
We next examined spontaneous in vitro cell death rates,
which consistently showed greater CD4+ Tg splenocyte viability compared
to CD4+ WT cells (P=0.006; Fig. 5B
). The
percentage of apoptotic CD4+ cells in Tg splenocyte cultures was
significantly lower than for WT mice (Fig. 5C
). Transgenic
CD4+ cells also showed decreased activation- and Fas-induced cell death
compared to WT mice (10 to 20% lower, not shown). In vitro
activation of T cells with suboptimal doses of anti-CD3-TcR antibody
yielded only moderately increased proliferation rates in Tg T cells
compared to WT cells (not shown), possibly the consequence of the
increased Tg CD4+ cell survival. In vivo BrdU labeling
(20
, 21)
showed a similar proportion of dividing T cells
in WT and Tg mice both in the CD4+ (15–16%
CD4+BrdUhigh) and the CD8+ cell pool (12–13%
CD8+BrdUhigh). These results thus provide
evidence that in vivo PI3K activation induces cell survival
and appears to contribute to the increased generation and/or
persistence of memory cells.
PTEN tumor suppressor inhibits p65PI3K-induced focus
formation
The pathology developed by p65PI3K Tg mice
was strikingly similar to that described in a
PTEN+/- mouse model (15)
. This
suggests that 3-phosphoinositides, rather than PTEN protein
substrates, give rise to the lymphoproliferative and autoimmune
disorder in PTEN+/- mice. We previously showed
that p65PI3K cooperates with v-raf to trigger
focus formation in 3T3 cells (14)
. To analyze whether PTEN
also counteracts the action of PI3K in cell transformation, we examined
the ability of PTEN to inhibit p65PI3K-induced
3T3 cell transformation. Here we show that ectopic expression of PTEN
inhibits focus formation by p65PI3K alone or in
combination with v-raf, but does not affect foci induced by v-raf alone
or by v-src (Fig. 6A
); partial inhibition was observed in v-ras-induced foci
(not shown). Analysis of a fraction of the transfected samples used in
focus formation assays showed that PTEN expression was two- to fourfold
higher than that of the endogenous enzyme (Fig. 6B
), and was
capable of inhibiting AKT induction by p65PI3K
(not shown). Similar results were observed using another constitutive
active PI3K mutant (26)
, p110-CAAX (not shown),
demonstrating that recombinant PTEN selectively counteracts cell
transformation mediated by constitutively active PI3K.
|
p65PI3K involvement in tumor development
Of the three available murine heterozygous loss mutants for PTEN,
one develops lymphoproliferative/autoimmune disease; the other two
PTEN+/- models exhibit lymph node hyperplasia
(27)
and a moderate predisposition to develop lymphomas,
which increases when secondary mutations are introduced by irradiation
(27
, 28)
. For efficient in vitro 3T3 cell
transformation, p65PI3K also requires cooperation
with other oncogenes. In vivo, p65PI3K
gave rise to the described premalignant lymphoproliferative disease. To
evaluate whether p65PI3K cooperates with other
pathways to induce tumor formation in vivo, we crossed
p65PI3K Tg mice with
p53-/- mice (17)
and examined
offspring for tumors. Whereas 46% of p53-/-
mice were alive at 5 months of age, all p65PI3K
Tg p53-/- mice had died by this age (Fig. 7A
). In addition, p53-/- littermates
developed lymphomas (67%) and sarcomas (33%) whereas
p65PI3K Tg p53-/- mice
developed only lymphomas (Fig. 7B
), which affected primarily
the thymus (Fig. 7C
). The phenotype of the thymic lymphomas
was similar in both mice except for CD3high
expression (Fig. 7D
), which was found in a larger proportion
of p65PI3K Tg p53-/-
thymic lymphomas. Some of these p65PI3K Tg
p53-/- thymic lymphomas also affected secondary
lymphoid organs, particularly those in which cells expressed
CD3high. T cell receptor Vß expression analysis
of CD3+ lymphomas demonstrated the clonal nature of these tumors (not
shown). All p53+/- mice analyzed were viable for
the first 6 months after birth, whereas viability was lower (80%) in
p65PI3K Tg p53+/- mice,
with death caused by generalized lymphomas. These results show that
expression of p65PI3K in T lymphocytes results in
greater predisposition to tumor development, cooperating with defects
in the tumor suppressor p53, to generate T cell lymphomas.
|
|
DISCUSSION |
|---|
|
TOPABSTRACTINTRODUCTIONMATERIALS AND METHODSRESULTSDISCUSSIONREFERENCES |
|---|
Adult p65PI3K Tg mice showed a dramatic increase
in activated/memory CD4+ T lymphocytes, indicating that T cells are
highly sensitive to an increase in PI3K-derived lipid products. The T
cell sensitivity to this active PI3K form suggests that PI3K activation
by the IL-2 growth factor receptor, described in in vitro
cell systems (18
, 29
, 30)
, may also induce in
vivo T cell survival. In addition to the lymphoproliferative
disease, p65PI3K Tg mice had elevated serum
immunoglobulin and autoantibody levels that led to autoimmune renal
disease. A similar process occurs in human systemic lupus erythematosus
(SLE), as well as in murine SLE models (MLR-lpr and
MLR-gld) (31)
. In these mice, disease develops
with age, resulting in an enlarged T cell population and autoantibody
production; disease development is associated with defective apoptosis
(32)
. Similarly, cell death defects appear to cause the
lymphoproliferative disorder in p65PI3K Tg mice.
The increased PI3K activity p65PI3K Tg mice
affected cell death in CD4+ but not CD8+ T cells, indicating
differential sensitivity of distinct T cell populations to PI3K
activation. Of the CD4+ cells, only memory T cells showed in
vivo cell death defects. This may explain the limited CD4+ T cell
expansion in young p65PI3K Tg mice, when the
memory compartment is small, and disease development in older mice,
when large numbers of memory cells have been generated (20
, 21)
.
The lower activation requirements of memory cells (23)
may
also facilitate their induction and, in turn, B cell activation at the
onset of autoimmune renal disease. Of the two mechanisms by which
autoreactive T cells cause autoimmunity, direct participation of
autoreactive T cells in tissue destruction or secondary activation of B
cells (31)
, T cells in p65PI3K Tg
mice appear to induce autoimmunity by activating B cells. The
multiorgan T lymphocyte infiltration in p65PI3K
Tg mice was remarkable, matched only by that observed in
CTLA4-/- mice (33
, 34)
and in
PTEN+/- mice (15)
; these latter
animals exhibit a pathology very similar to that in the
p65PI3K Tg mice (see below). All of these mice
exhibit autoimmune disease, but whereas the actively dividing activated
T lymphocytes of CTLA4-/- mice cause multiorgan
tissue destruction, the memory population of T lymphocytes in
p65PI3K Tg mice provoke no obvious tissue
destruction (under study) except for the induction of B cell-mediated
glomerulonephritis. In p65PI3K Tg mice, T cell
infiltration may be enhanced by PI3K involvement in integrin-induced
migration, as has been suggested based on in vitro models
(35)
.
Comparison of the p65PI3K Tg mouse phenotype with
that of one of the PTEN+/- mouse models
(15)
showed that both animals undergo remarkably similar
lymphoproliferative and autoimmune disease processes. The
lymphoproliferative disorder in p65PI3K Tg mice
is due to an alteration in the T cell compartment to which transgene
expression is restricted, suggesting that T cells may also be essential
in triggering the lymphoproliferative/autoimmune disease in
PTEN+/- mice. The earlier development of the
pathological process in PTEN+/- mice as compared
to p65PI3K Tg mice may be due the generalized
genetic defect (in T and B cells) in the former animals
(15)
. Lymphoproliferative disease was found in only one of
the three PTEN+/- mouse models
(15)
; the other two models are predisposed to
hyperproliferative lymphoid disorders such as lymph node hyperplasia
(27)
and T cell lymphomagenesis, particularly after
irradiation (27
, 28)
. All these mice also showed variably
increased transformation susceptibility in other tissues (27
, 28
, 36)
. The differences among these three models suggest that, as
in murine SLE models (31)
, the distinct genetic background
contributes to determining disease development. The alterations in
other cell types were not observed in p65PI3K Tg
mice, as the transgene is expressed only in T cells. Nevertheless, the
fact that PI3K activation in p65PI3K Tg mice
causes such a similar pathology to that developed in one of the
PTEN+/- mouse models suggests that, of the
different PTEN substrates (11
12
13)
,
3-phosphoinositides are responsible for inducing the
lymphoproliferative/autoimmune disease.
The observation that PTEN inhibited p65PI3K-induced focus formation, but not v-raf- or v-src-induced foci, constitutes clear evidence that PTEN suppresses tumor formation via PI3K pathways. Finally, the earlier development of T cell lymphomas in p65PI3K Tg p53-/- mice shows that activation of PI3K predisposes to tumor formation and that this pathway cooperates with genetic defects in p53. Together, our results demonstrate the essential role of PI3K-derived lipid products in increasing cell survival in vivo, in regulation of lymphocyte homeostasis, and in tumor generation. This supports a model in which increased levels of only one PTEN substrate, the 3-phosphoinositides, induce transformation.
|
ACKNOWLEDGMENTS |
|---|
|
FOOTNOTES |
|---|
|
REFERENCES |
|---|
|
TOPABSTRACTINTRODUCTIONMATERIALS AND METHODSRESULTSDISCUSSIONREFERENCES |
|---|
. Science 283,393-396 subunit of phosphoinositide 3-kinase. Science 283,390-392This article has been cited by other articles:
|
|
 |
|
  U. Sela, M. Dayan, R. Hershkoviz, O. Lider, and E. Mozes A Peptide That Ameliorates Lupus Up-Regulates the Diminished Expression of Early Growth Response Factors 2 and 3 J. Immunol., February 1, 2008; 180(3): 1584 - 1591. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 I. Alcazar, M. Marques, A. Kumar, E. Hirsch, M. Wymann, A. C. Carrera, and D. F. Barber Phosphoinositide 3 kinase {gamma} participates in T cell receptor induced T cell activation J. Exp. Med., November 26, 2007; 204(12): 2977 - 2987. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 C.-P. Liu, Y.-C. Kuo, C.-C. Shen, M.-H. Wu, J.-F. Liao, Y.-L. Lin, C.-F. Chen, and W.-J. Tsai (S)-Armepavine inhibits human peripheral blood mononuclear cell activation by regulating Itk and PLC{gamma} activation in a PI-3K-dependent manner J. Leukoc. Biol., May 1, 2007; 81(5): 1276 - 1286. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 C. Xie, R. Patel, T. Wu, J. Zhu, T. Henry, M. Bhaskarabhatla, R. Samudrala, K. Tus, Y. Gong, H. Zhou, et al. PI3K/AKT/mTOR hypersignaling in autoimmune lymphoproliferative disease engendered by the epistatic interplay of Sle1b and FASlpr Int. Immunol., April 1, 2007; 19(4): 509 - 522. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 J. A. Deane, M. G. Kharas, J. S. Oak, L. N. Stiles, J. Luo, T. I. Moore, H. Ji, C. Rommel, L. C. Cantley, T. E. Lane, et al. T-cell function is partially maintained in the absence of class IA phosphoinositide 3-kinase signaling Blood, April 1, 2007; 109(7): 2894 - 2902. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 J. A. Gustin, C. K. Korgaonkar, R. Pincheira, Q. Li, and D. B. Donner Akt Regulates Basal and Induced Processing of NF-{kappa}B2 (p100) to p52 J. Biol. Chem., June 16, 2006; 281(24): 16473 - 16481. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
D. F. Barber, A. Bartolome, C. Hernandez, J. M. Flores, C. Fernandez-Arias, L. Rodriguez-Borlado, E. Hirsch, M. Wymann, D. Balomenos, and A. C. Carrera Class IB-Phosphatidylinositol 3-Kinase (PI3K) Deficiency Ameliorates IA-PI3K-Induced Systemic Lupus but Not T Cell Invasion J. Immunol., January 1, 2006; 176(1): 589 - 593. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 R.-i. Fukuda, A. Hayashi, A. Utsunomiya, Y. Nukada, R. Fukui, K. Itoh, K. Tezuka, K. Ohashi, K. Mizuno, M. Sakamoto, et al. Alteration of phosphatidylinositol 3-kinase cascade in the multilobulated nuclear formation of adult T cell leukemia/lymphoma (ATLL) PNAS, October 18, 2005; 102(42): 15213 - 15218. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
R. G. Jones, S. D. Saibil, J. M. Pun, A. R. Elford, M. Bonnard, M. Pellegrini, S. Arya, M. E. Parsons, C. M. Krawczyk, S. Gerondakis, et al. NF-{kappa}B Couples Protein Kinase B/Akt Signaling to Distinct Survival Pathways and the Regulation of Lymphocyte Homeostasis In Vivo J. Immunol., September 15, 2005; 175(6): 3790 - 3799. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 S. Vignot, S. Faivre, D. Aguirre, and E. Raymond mTOR-targeted therapy of cancer with rapamycin derivatives Ann. Onc., April 1, 2005; 16(4): 525 - 537. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 R. A. Lacalle, C. Gomez-Mouton, D. F. Barber, S. Jimenez-Baranda, E. Mira, C. Martinez-A., A. C. Carrera, and S. Manes PTEN regulates motility but not directionality during leukocyte chemotaxis J. Cell Sci., December 1, 2004; 117(25): 6207 - 6215. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 C. Gomez-Mouton, R. A. Lacalle, E. Mira, S. Jimenez-Baranda, D. F. Barber, A. C. Carrera, C. Martinez-A., and S. Manes Dynamic redistribution of raft domains as an organizing platform for signaling during cell chemotaxis J. Cell Biol., March 1, 2004; 164(5): 759 - 768. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 N. Li, K. Nakamura, Y. Jiang, H. Tsurui, S. Matsuoka, M. Abe, M. Ohtsuji, H. Nishimura, K. Kato, T. Kawai, et al. Gain-of-function polymorphism in mouse and human Ltk: implications for the pathogenesis of systemic lupus erythematosus Hum. Mol. Genet., January 15, 2004; 13(2): 171 - 179. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 N. W. C. J. van de Donk, D. Schotte, M. M. J. Kamphuis, A. M. W. van Marion, B. van Kessel, A. C. Bloem, and H. M. Lokhorst Protein Geranylgeranylation Is Critical for the Regulation of Survival and Proliferation of Lymphoma Tumor Cells Clin. Cancer Res., November 15, 2003; 9(15): 5735 - 5748. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
B. Alvarez, E. Garrido, J. A. Garcia-Sanz, and A. C. Carrera Phosphoinositide 3-Kinase Activation Regulates Cell Division Time by Coordinated Control of Cell Mass and Cell Cycle Progression Rate J. Biol. Chem., July 11, 2003; 278(29): 26466 - 26473. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
L. Rodriguez-Borlado, D. F. Barber, C. Hernandez, M. A. Rodriguez-Marcos, A. Sanchez, E. Hirsch, M. Wymann, C. Martinez-A., and A. C. Carrera Phosphatidylinositol 3-Kinase Regulates the CD4/CD8 T Cell Differentiation Ratio J. Immunol., May 1, 2003; 170(9): 4475 - 4482. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
C. Jimenez, C. Hernandez, B. Pimentel, and A. C. Carrera The p85 Regulatory Subunit Controls Sequential Activation of Phosphoinositide 3-Kinase by Tyr Kinases and Ras J. Biol. Chem., October 25, 2002; 277(44): 41556 - 41562. [Abstract] [Full Text |
raf (1.5
µg) alone or in the presence of pRK5-PTEN (1 µg); or
pSG5-p65PI3K (1.5 µg) plus LXV3
p65PI3K Tg
p53-/- (n=25); 
p53-/-
(n=24); 
p65PI3K Tg p53+/-
(n=13); • p53+/- (n=18).
B) Percentage of p53-/- or
p65PI3K Tg p53-/- mice developing lymphomas.
C) Percentage of p53-/- or
p65PI3K Tg p53-/- mice developing thymic
lymphomas. D) Phenotype of the thymic lymphomas examined
by flow cytometry.