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 Previous Article | Table of Contents | Next Article 
Blood, Vol. 92 No. 1 (July 1), 1998:
pp. 252-258
Interleukin-15 Is an Autocrine/Paracrine Viability Factor for
Cutaneous T-Cell Lymphoma Cells
By
Udo Döbbeling,
Reinhard Dummer,
Elisabeth Laine,
Natascha Potoczna,
Jian-Zhong Qin, and
Günter Burg
From the Department of Dermatology, University Hospital Zurich,
Switzerland.
 |
ABSTRACT |
In this study we investigated the role of interleukin-15 (IL-15) in
the immunobiology of cutaneous T-cell lymphoma (CTCL) cells. Using cell
culture techniques, reverse transcriptase-polymerase chain reaction
(RT-PCR), and immunhistochemistry we found that IL-15, like IL-7, is a
growth factor for the Sézary cell line SeAx and that both
cytokines prolonged the survival of malignant T cells directly isolated
from Sézary syndrome (SS) patients. Both IL-15 and IL-7 were more
potent than IL-2. IL-4 and IL-9, whose receptors share the same gamma
chain with the receptors of IL-2, IL-7, and IL-15, did not sustain the
growth of CTCL cells, indicating that signaling through the common
gamma chain ( c) is not sufficient for continuous growth. IL-13 and
tumor necrosis factor- (TNF-) had no effect. IL-7 and IL-15 also
supported the growth of SeAx cells in the presence of the apoptosis
inducing agents dexamethasone and retinoic acid. The analysis of
patient Sézary cells and three CTCL cell lines by RT-PCR showed
that all these cells expressed IL-15 mRNA, but only a few (25%)
produced IL-7 mRNA. Immunohistological analyses of skin biopsy samples of SS and Mycosis fungoides patients showed immunoreactivity for IL-15
in basal cell layer keratinocytes and in the infiltrating lymphocytes.
We conclude that IL-15 is a growth or viability factor for CTCL-derived
cell lines or shortly cultivated Sézary cells. The findings that
IL-15 mRNA can be detected in Sézary syndrome peripheral blood
mononuclear cells and that the IL-15 protein is detected in skin
sections from CTCL patients suggest that IL-15 plays an important role
in the biology of CTCL.
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INTRODUCTION |
CUTANEOUS T-CELL lymphoma (CTCL) is a
heterogeneous group of lymphoproliferative disorders of the
skin.1 The most frequent forms of CTCL are Mycosis
fungoides (MF) and its leukemic counterpart the Sézary syndrome
(SS). One striking feature of this disease is that the lymphocyte
proliferations remain restricted to the skin. This fact implies that
CTCL cells remain dependent on the specific cutaneous microenvironment,
including cytokines and adhesion molecules. Keratinocytes produce a
variety of T-cell growth supporting cytokines such as interleukin-7
(IL-7),2 which is necessary to cultivate freshly isolated
Sézary cells and some established Sézary cell
lines.3,4 Initially IL-7 has been identified as a growth
factor for lymphocyte precursors and T cells and its high affinity
receptor contains besides a specific chain as well as the IL-2
receptor chain.5
IL-15 has been identified as a T- and B-cell growth stimulating
cytokine6,7 produced by several cell types and
tissues,6 including skin.8,9 The IL-15 receptor
contains the  and chain of the IL-2 receptor and a recently
identified specific chain.10,11 IL-15 can replace IL-2
in several systems,6,8,10 but mostly it proved to be less
effective than IL-2.
In this study we investigated whether IL-15 is a growth or viability
factor for CTCL cells in vitro and whether it is synthesized by CTCL or
other skin cells and may thus act as an autocrine or paracrine growth
factor for CTCL cells.
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MATERIALS AND METHODS |
Cell culture.
The cell line HUT78 (SS) was obtained from European Collection of
Animal Cell Cultures (Salisbury, UK). The cell lines MyLa (MF) and SeAx (SS) were kind gifts of Dr Keld Kaltoft (University of
Aarhus, Denmark).12 HUT 78 and MyLa and patient
Sézary cells were grown in HEPES-buffered RPMI 1640 medium with 2 mmol/L glutamine, supplemented with 10% fetal calf serum (FCS), 0.25 mg/mL amphotericin B, 100 U penicillin G, 100 U streptomycin, and 1 mmol/L pyruvate. SeAx cells were grown under the same conditions with
the exception that 10% human serum (HS) instead of 10% FCS was used.
The concentrations of the cytokines were as follows: IL-2, 50 ng/mL
(100 U); IL-4, 20 ng/mL (100 U); IL-7, 5 ng/mL (10 U); IL-9, 10 ng/mL
(10 U); IL-13, 600 ng/mL (100 U); IL-15, 10 ng/mL (10 U); tumor
necrosis factor- (TNF-), 50 pg/mL (1 U). The concentrations of
dexamethasone (DEX) and retinoic acid (RA) were 1 µmol/L. Recombinant
cytokines (IL-2, IL-4, IL-7, IL-9, IL-13, TNF-) were from R&D
Systems Europe (Abingdon, UK), with the exception of IL-15, which was
delivered by PeproTech EC Ltd (London, UK). DEX and RA were from Sigma
Chemie (Buchs, Switzerland).
Blood and skin samples.
Skin biopsy and blood samples were taken primarily for diagnostic
purposes with informed consent of the patients and the specimens used
were surplus material available after all the routine diagnostic procedures. The average age of patients was 60.4 + 14.1 years and they
were diagnosed as SS CTCL stage III (seven patients) and stage IVa (two
patients). The assignment to a certain stage was done according to the
recommendations of the European Organization for Research and Treatment
of Cancer Cutaneous Lymphoma Project Group.13
Sézary cells from patients' blood were isolated by Ficoll
(Pharmacia, Uppsala, Sweden) gradient centrifugation and sorted by two-color fluorescence-activated cell sorter (FACS) using
antibodies against CD4 and the v region of their T-cell receptor.14
RNA preparation DNA synthesis and reverse transcriptase-polymerase
chain reaction (RT-PCR).
RNA from punch biopsy samples (4 mm), small spindles of skin (50 to 200 mg), or culture cells was prepared as described
earlier.15,16 For cDNA preparation, 2 µg of total RNA was
incubated for 1 hour at 37°C in a 20-µL reaction
with 2 µL random hexamer primers (Boehringer Mannheim, Mannheim,
Germany), 1 mmol/L nucleotide triphosphates (NTPs), 1 µL
RNA-Guard (Pharmacia), 2 µL 10× RT-buffer, and 1 µL Moloney murine leukemia virus (Mo-MuLV) RT (New
England Biolabs, Beverly, MA).
In a 20-µL reaction, 4 µL of the of cDNA reaction was incubated
with 1 µmol/L upper and lower primer, 0.1 mmol/L NTPs, 2 µL 10× RT-buffer, and 0.2 µL Taq-polymerase (Boehringer Mannheim). The DNA was amplified in 35 cycles of 1 minute at 94°C
(denaturation), 1 minute at 55°C (annealing), and 1 minute 30 seconds at 72°C (elongation), and the products were analyzed on an
ethidium bromide-stained 2% Agarose gel (Boehringer, Mannheim). The
sequences for the primers were the following: IL-15 up,
GGATGGCTGCTGGAAACC; IL-15 low, GGGAGCCCTGCACTGAAA. The oligonucleotides
were synthesized by Microsynth (Balgach, Switzerland).
PCR enzyme-linked immunosorbent assay (ELISA). For the PCR ELISA, a
20-nucleotide capture probe mapping within the amplified IL-15 cDNA was
selected using the OLIGO 4.0 program (National Biosciences Inc,
Plymouth, MN). This probe was synthesized as a
single-stranded biotinylated oligonucleotide (Microsynth). PCR ELISA
was performed according to kit directions (Boehringer Mannheim). The
specific capture probe/PCR product hybrids were bound to
streptavidin-coated microtiter plates via the biotin label of the
probes. After washing, the immobilized hybrids were treated with
antidigoxigenin peroxidase-conjugated antibody and ABTS,
a substrate for the peroxidase. The plates were measured by reading
with a photometer at a wavelength of 492 nm, and values that were
higher than 2× the reading of the PCR reaction mix with water
instead of cDNA were judged to be positive.
Immunohistochemistry.
All specimens were snap frozen in liquid nitrogen, embedded in
tissue-tec (GIBCO, Grand Island, NY), and stored at
 80°C until processing. Cryostat sections of 5 µm were cut
onto gelatine-coated microscope slides and air-dried. Alkaline
anti-alkaline phosphatase (APAAP)-immunohistochemistry (reagents from
DAKO, Copenhagen, Denmark) was performed as
published.14 The anti-IL-15 antibodies used are
commercially available (PeproTech, London, UK). In
addition, all samples were also examined for reactivity with anti-CD3,
-CD4, and -CD8 (reagents from DAKO).
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RESULTS |
IL-15 and IL-7 can replace IL-2 as growth factor of SeAx cells and
prolong the survival of patient Sézary cells in vitro.
The fact that IL-2-dependent CTCL cell lines could be
established12,17,18 points to the possibility that Ils
which use receptors that share some common components with the IL-2
receptor may be growth factors for CTCL cells. Therefore, we tested
first whether IL-7 and IL-15, whose receptor also uses the same chain as the IL-2 receptor, are able to substitute IL-2 as a growth factor for the IL-2-dependent Sézary cell line SeAx.
Figure 1 shows that IL-15 and IL-7 are
better growth factors for SeAx cells than IL-2, although lower
concentrations of these ILs (10 ng/mL IL-15 = 10 U, 5 ng/mL IL-7 = 10 U, 50 ng/mL IL-2 = 100 U) have been used. IL-15 increased the effect of
IL-7 on the growth of SeAx when both were administered together,
whereas IL-2 did not increase the growth of SeAx cells in combination
with IL-7 (data not shown).
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| Fig 1.
The effect of IL-2 (50 ng/mL = 100 U), IL-7 (5 ng/mL
= 10 U), and IL-15 (10 ng/mL = 10 U) on the growth of the CTCL cell
line SeAx. The withdrawal of these cytokines leads to cell death. The number of the cells is given in percent of the cell number used to
start the cell culture (3 to 5 × 105/mL) on the y-axis in
a logarithmic scale. The time of incubation is given in days on the
x-axis. The data were obtained from four independent experiments and
standard variations were between 10% and 30%. Note that the number of
cells is given on a logarithmic scale, so that standard deviations of
10% to 30% are not visible.
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Ten units per milliliter of IL-7 or IL-15 was significantly more
efficient than 5 U/mL IL-7 or IL-15; however, a further increase of
both IL concentrations up to 100 U/mL had no significant
growth-supporting effect. High IL-15 concentrations (>50 U/mL) may be
even detrimental. IL-15 and IL-7 work through different receptors as an
antibody against IL-15 reduced the effect of IL-15, but not that of
IL-7 (data not shown).
We next investigated whether IL-15 can sustain the survival of isolated
Sézary cells freshly isolated from patients blood. Figure 2A and B show that the IL-15 and
IL-7 concentrations used for SeAx cells can prolong the survival of
these cells. Higher concentrations (20 ng/mL and 40 ng/mL,
respectively) yielded an even longer survival of these cells (Fig 2B).
IL-7 was more effective per se than IL-15 and, as in SeAx cells, the
combination of IL-15 and IL-7 was more effective than each IL alone.
These experiments show that IL-15 is a survival factor for Sézary
cells in vitro, but IL-15 is not sufficient to maintain a continuous
growth of these cells.
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| Fig 2.
IL-7 and IL-15 prolong the survival of patient
Sézary cells in vitro. The IL concentrations are the same as in
Fig 1. The cells of patient 1 (A) were kept at these concentrations for
the whole time of the experiment. The transient increase of the number of cells from patient 2 (B) on day 13 is caused by an increase of the
concentrations of IL-7 and IL-15 to 20 ng/mL and 40 ng/mL, respectively. The data were obtained from three independent
experiments.
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No increase of the growth rate of the IL-7/IL-15-independent cell
lines HUT 78 and MyLa was observed when IL-7, IL-15, or both were added
to the medium (data not shown).
The influence of IL-4, IL-9, and IL-13 on the survival of SeAx cells.
The c chain of the IL-2 receptor is also shared by the receptors of
IL-4 and IL-9. To see whether signaling through the c chain is
sufficient for the survival of SeAx cells, these two ILs were tested
for whether they could sustain the growth of these cells. IL-13, whose
receptor uses the same chain as IL-4, was also included in this
analysis. Figure 3 shows that none of these three ILs is able to sustain the growth of SeAx cells at the given concentrations, indicating that growth signals mediated through the
c chain alone are not sufficient for the growth of SeAx cells. No
effects of IL-9 and IL-13 were seen even at concentrations of 1,000 U/mL, whereas 1,000 U of IL-4 could sustain the growth of SeAx cells.
This may be either due to the activation of low affinity IL-4 receptors
or unspecific effects.
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| Fig 3.
IL-4, IL-9, and IL-13 are not growth factors for SeAx
cells. The inefficiency of IL-4 and IL-9 indicates that
signals through their common receptor chain which they also share
with the receptors of IL-2, IL-7, and IL-15 are not sufficient to
sustain the growth of this cell line. The concentrations for IL-7 and
IL-15 were the same ones as in Fig 1. The concentrations for IL-4 (50 U), IL-9 (50 U), and IL-13 were 90 ng/mL (100 U), 50 ng/mL, and 600 ng/mL (100 U), respectively. The molecular weights of the ILs used are
13 kD (IL-15 and IL-13), 14 kD (IL-4 and IL-9), 15 kD (IL-2), and 17 kD
(IL-7). The results have been obtained from three independent
experiments.
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IL-15 and IL-7 enable SeAx cells to survive in the presence of DEX
and RA.
In early stages cutaneous T-cell lymphomas are treated with
glucocorticoids and RA, which initially cause a regression of the skin
lesions. Glucocorticoids and RA have been described as cell
death-promoting agents and it may be that these agents are able to
kill CTCL cells. To see whether IL-15 and IL-7 are able to sustain the
growth of SeAx cells also in the presence of the synthetic
glucocorticoid DEX and RA, the cells were incubated as previously
described with 10 ng/mL IL-15, 5 ng/mL IL-7, and additionally with 1 µmol/L DEX and 1 µmol/L RA, respectively; ie, concentrations that
have been shown to saturate cellular glucocorticoid and RA receptors.
Figure 4 shows that DEX and RA reduce the
growth of SeAx cells in the presence of IL-7 and IL-15 and accelerate
the cell death in the absence of these ILs. The addition of
dexamethasone or RA (on days 0 and 6 in Fig 4) reduces the total number
of cells only weakly in the presence of IL-15 and IL-7 and the cell
number increases again 2 days after the addition of DEX and 4 to 6 days after the addition of RA. These experiments show that the effect of DEX
and RA is only transient in the presence of IL-7 and IL-15.
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| Fig 4.
The synthetic glucocorticoid DEX and RA reduce the growth
of SeAx cells in the presence of IL-7 and IL-15 and quicken cell death
in the absence of these cytokines. The decrease in cell number of the
DEX- and RA-treated cells is caused by a second addition of another 1 µmol/L DEX or RA, respectively. The results have been obtained from
three independent experiments.
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The IL-15 gene is expressed in CTCL cells.
IL-independent cell lines have been established from several CTCL
patients. One way this independence is established is that during tumor
development mutant CTCL cells acquire the ability to produce enough
IL-7 or IL-15 to sustain their own growth in an auto/paracrine way.
Therefore, we tested the expression of the IL-15 and IL-7 genes by
RT-PCR. We found that IL-15 was expressed in the IL-independent CTCL
cell lines HUT 78 and MyLa, but also in SeAx cells and in all of the
blood samples from nine different Sézary patients
(Fig 5). For all CTCL samples we observed
two bands of 204 and 323 bp (Fig 5) that correspond to the two
described splice isoforms.19 The identity of the PCR
products was confirmed by PCR ELISA with an internal IL-15
mRNA-specific capture probe and digests of the PCR product with the
restriction enzymes PvuII, which cuts only the 305-bp isoform,
and AflII, which cuts both forms (data not shown). The 305-bp
signal of normal peripheral blood lymphocytes (PBLs) was
weaker than those of the CTCL samples (Fig 5, lane 13) and any IL-15
band was absent in PBLs which had been depleted of monocytes (Fig 5,
lane 14). IL-7 expression was only found in two cell lines and in
samples of one patient (not shown).
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| Fig 5.
(A) Representative IL-15 RT-PCR results from the three
CTCL cell lines HUT78, MyLa, SeAx, and Sézary cells from nine
patients. M, Boehringer marker V; the sizes of the most important
marker bands are given on the left. Lanes 1 through 3, the cell lines MyLa, HuT 78, and SeAx; lanes 4 through 12, Sézary cells from nine patients; lane 13, PBLs of a healthy donor; lane 14, monocyte-depleted PBLs of a healthy donor. (B) Corresponding results of
a -actin PCR, which served as a control. The sizes of the RT-PCR
products are given on the left.
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To see whether the IL-7- and IL-15-independent MyLa and HUT 78 cells
were able to secrete IL-15, the IL-15 concentrations in the media of
these cells were measured by an IL-15 ELISA 48 hours after the last
change of the medium. In all measurements the IL-15 levels were below
the detection limit of the assay (50 pg/mL).
TNF- is not a survival factor for Sézary cells.
It has been recently reported that the Sézary cell line HUT 78 produces TNF- and that TNF- promotes the growth of these cells.20 Therefore, we tested whether TNF-
concentrations that have been reported for HUT 78 cells can promote the
growth of SeAx cells. Figure 6 shows that
TNF- is detrimental for the growth of SeAx cells. A TNF-
concentration of 50 pg/mL strongly reduces the growth of SeAx cells
despite the presence of IL-15 and IL-7, and 250 pg/mL TNF- kills the
SeAx cells within 2 weeks. Therefore, TNF- cannot be considered to
be a general growth factor for Sézary cells. The resistance of
HUT78 cells to TNF- may be explained by the assumption that this
cell line represents a late stage of CTCL in which additional mutations
have occurred.
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| Fig 6.
TNF- reduces the growth of SeAx cells. TNF- has
been reported to be an autocrine growth factor for the Sézary
cell line HUT 78. The TNF- concentration (50 pg/mL) used for the
SeAx cells is the same as the one that has been reported to be secreted
by HUT 78 cells. The results have been obtained from three independent experiments.
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Histological findings.
Immunoreactivity for IL-15 was detected in epidermal cells, especially
in the basal layer of the epidermis, in cells with a dendritic
morphology in the dermis and in mononuclear cells. This
immunoreactivity could be blocked by exogenous recombinant IL-15. In
early CTCL lesions (patches) (n = 5), immunoreactivity was strongest in
the junction zone between epidermis and dermis where the lymphocytic
infiltrates show their highest densities (Fig 7). In advanced lesions (plaques) (n = 5), immunoreactivity was also detected in deeper parts of the dermis in
areas heavily infiltrated by mononuclear cells
(Fig 8).
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| Fig 7.
Detection of IL-15 in early CTCL lesion (patch stage) by
an IL-15 antibody. The binding of the specific antibody to IL-15 was
detected by an alkaline phosphatase (AP) coupled second antibody directed against the Fc region of the IL-15 antibody. Binding of the
IL-15 antibody after APAAP staining was strongest in the junction zone
between epidermis and dermis where CTCL cells show their highest
densities. The specificity of the binding of the IL-15 antibody was
tested by a competition experiment with recombinant IL-15 (not shown).
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| Fig 8.
A more advanced CTCL lesion (plaque stage):
immunoreactivity for IL-15 after APAAP staining was detected in the
junctional area and in deeper parts of the dermis heavily infiltrated
by mononuclear cells.
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DISCUSSION |
IL-15 has several common activities with IL-2 and IL-7, which are
established growth factors for T cells. IL-7 is expressed in the skin and supports the growth of Sézary cells in
vitro.2,3 Because IL-15 is also produced in the skin and
the receptor of IL-15 shares the c chain with the IL-2 and IL-7
receptors and a common chain with the IL-2 receptor, we
investigated whether IL-15 could be a growth factor for CTCL cells.
Experiments with the Sézary cell line SeAx showed that IL-15 is
sufficient to support the growth of the this cell line SeAx. IL-15 and
IL-7 proved to be more efficient than IL-2. In contrast to IL-2, IL-7, and IL-15, IL-9 had no effect and IL-4 was only effective at very high
concentrations, indicating that signaling through the common chain
of their receptors is not sufficient and that additional signals
through the and chains of the IL-2, IL-7, and IL-15 receptors
are necessary. In this respect CTCL cells differ from peripheral blood
T cells for which it already has been shown that IL-4 concentrations as
low as 2 to 10 U/mL can protect them from cell death.21
IL-15 and IL-7 help SeAx cells to survive also in the presence of the
apoptosis inducing agents DEX and RA, indicating that these two ILs are
able to counteract the cell death promoting effects of these two agents
by a still unknown way. The diminished growth of SeAx cells in the
presence of DEX may be due to the fact that DEX can downregulate the
expression of the IL-15 receptor chain.22
The in vitro experiments with Sézary cell isolated from the blood
of patients also show that IL-15 can support the survival of these
cells. Under these conditions IL-7 was more effective than IL-15, but
IL-15 was more effective than IL-2 and also could enhance the effect of
IL-7.
Our RT-PCR analyses showed that the cell line SeAx and patients'
Sézary cells express IL-15 mRNA. Despite this endogenous IL-15
gene transcription, these cells did not grow in the absence of IL-15 in
vitro. An explanation may be that the amount of the produced IL-15 may
be too low to sustain growth under in vitro conditions, because
paracrine or autocrine IL-15 may be too strongly diluted by diffusion
into the medium and, thus, too little IL-15 may bind to its receptors
to have an effect on the cell.
Our immunohistological investigations detected IL-15 immunoreactivity
restricted to the junction zone between epidermis and dermis in early
lesions of MF (Fig 7). In this area keratinocytes, dermal dendritic
cells, or lymphocytes could produce this cytokine. Because the area of
IL-15 production includes the area where CTCL cells preferentially
home, we propose that IL-15 is a paracrine/autocrine growth or
viability factor and/or a chemotactic factor in early CTCL
lesions.
In advanced lesions (plaques), IL-15 immunoreactivity was also detected
in deeper parts of the dermis in areas heavily infiltrated by
mononuclear cells (Fig 8). This can confirm our mRNA results, indicating that the dominant T-cell clone can produce the cytokine itself. It is possible that autocrine IL-15 production increases during
tumor progression and that CTCL cells therefore lose their dependency
on the cutaneous microenvironment.
Because IL-15 acts not only as a T-cell growth factor6 but
also as a chemoattractant for T cells,23 IL-15 derived from keratinocytes and skin dendritic cells may attract CTCL cells and
sustain their growth in skin. Thus, IL-15 may be a key molecule for the
epidermotropism seen in CTCL. In late stages, CTCL may become
IL-7/IL-15 independent either by autocrine IL-15 production or by a
shortcut of the IL-7 and IL-15 signaling pathways. These cells will
then lose their epidermotropism and settle other organs. Indirect
evidence for a biological effect of IL-15 may be the production of IL-5
by CTCL cells,14 because it has been shown that IL-15 can
promote the expression of IL-5 in human T-helper cells.24
The 5 untranslated region (5 UTR) of the IL-15 gene has
an unusual structure because it contains 10 AUGs in front of the start
of translation. It has been emphasized by Kozak25 that AUGs
in front of the translation starting AUG can drastically reduce the
efficiency of translation. The deletion of these upstream AUGs may lead
to an increase of IL-15 production that may give cells with such
deletions a growth advantage over nonmutated cells. Such a
constellation has been found in the leukemia cell line HUT-102,26,27 where an incomplete human T- cell
lymphotrophic virus I copy is integrated in the cellular
genome in front of the IL-15 gene. This integration eliminated 8 of the
10 upstream AUGs and increased the IL-15 production in these
cells.28 Whether such mutations occur in the IL-15 gene
5 UTRs of cutaneous T-cell lymphoma cells has yet to be
established. It has been recently shown that the leader peptides of
both IL-15 splice forms lead only to inefficient IL-15 processing and
secretion.29 Thus, it could theoretically be that the IL-15
gene in CTCL is expressed and translated into protein, but not
secreted, and independence from IL-7 and IL-15 may be acquired by
different mechanisms; eg, by mutations in the IL-7 or IL-15 signaling
pathways that mimic constitutive stimulation. However, inefficient
secretion does not mean no secretion, because Tagaya et
al30 have found that the IL-15 form with the long leader
peptide is sufficiently secreted to have a biological effect, although
the secretion efficiency was very low. Our histological experiments
with an IL-15 antibody clearly show that IL-15 is efficiently
translated into IL-15 protein and even minor IL-15 secretion may be
efficient at short distances. Mutations in the leader peptide regions
of the IL-15 gene may lead to higher IL-15 production and secretion
which, in turn, could stimulate CTCL cell growth in an autocrine way.
However, extracellular IL-15 may not be the only form of IL-15 that is
important for CTCL cells, as Tagaya et al30 also showed
that the short leader peptide form of IL-15 is retained in the cell and
accumulates in the nucleus. This finding suggests that this form of
IL-15 may be a ligand for an intracellular protein that may influence
gene expression.
In summary, our results and the recent data on IL-15 gene regulation
support the hypothesis that IL-15 together with interferon- inducible protein31 and IL-7 plays a key role
in epidermotropism and tumor progression in CTCL.
| |
FOOTNOTES |
Submitted July 14, 1997;
accepted February 25, 1998.
Supported by the Swiss Cancer League, the Swiss National Science
Foundation (Grants No. 3100-43244.95/1 and 31-43635.95 to G.B. and
R.D.), and the Kanton of Zurich.
Address reprint requests to Udo Döbbeling, PhD, Department of
Dermatology, University Hospital Zurich, Gloriastrasse 31, CH-8091
Zurich, Switzerland.
The publication costs of this article were defrayed in part by page charge payment. This article must therefore be hereby marked "advertisement" is accordance with 18 U.S.C. section 1734 solely to indicate this fact.
| |
ACKNOWLEDGMENT |
The authors thank F. Bonvin, A. Flace, H. Grundmann, S. Manolio, and B. Müller for their excellent technical assistance, and M. Johnson
and M. Bär for the preparation of the photographs.
| |
REFERENCES |
1.
Burg G,
Dummer R,
Dommann S,
Nestle F,
Nickoloff B:
Pathology of cutaneous T-cell lymphoma.
Hematol Oncol Clin North Am
9:961,
1995[Medline]
[Order article via Infotrieve]
2.
Matsue H,
Bergstresser PR,
Takashima A:
Keratinocyte-derived IL-7 serves as a growth factor for dendritic epidermal T cells in mice.
J Immunol
151:6012,
1993[Abstract]
3.
Dalloul A,
Laroche L,
Bagot M,
Mossalayi MD,
Fourcade C,
Thacker DJ,
Hogge DE,
Merle Béral H,
Debré P,
Schmitt C:
Interleukin-7 is a growth factor for Sézary lymphoma cells.
J Clin Invest
90:1054,
1992
4.
Foss FM,
Koc Y,
Stetler-Stevenson MA,
Nguyen DT,
O'Brien MC,
Turner R,
Sausville EA:
Costimulation of cutaneous T-cell lymphoma cells by interleukin-7 and interleukin-2: Potential autocrine or paracrine effectors in the Sézary syndrome.
J Clin Oncol
12:326,
1994[Abstract]
5.
Nowak R:
"Bubble boy" paradox resolved.
Science
262:1818,
1993[Free Full Text]
6.
Grabstein KH,
Eisenman J,
Shanebeck K,
Rauch C,
Srinivasan S,
Fung V,
Beers C,
Richardson J,
Schoenborn MA,
Ahdieh M,
Johnson L,
Alderson M,
Watson JD,
Anderson DM,
Giri JG:
Cloning of a T cell growth factor that interacts with the beta chain of the interleukin-2 receptor.
Science
264:965,
1994[Abstract/Free Full Text]
7.
Armitage RJ,
Macduff BM,
Eisenman J,
Paxton R,
Grabstein KH:
IL-15 has stimulatory activity for the induction of B cell proliferation and differentiation.
J Immunol
154:483,
1995[Abstract]
8.
Mohamadzadeh M,
Takashima A,
Dougherty I,
Knop J,
Bergstresser PR,
Cruz PD:
Ultraviolet B radiation up-regulates the expression of IL-15 in human skin.
J Immunol
155:4492,
1995[Abstract]
9.
Blauvelt A,
Asada H,
Klaus-Kovtun V,
Altman DJ,
Lucey DR,
Katz SI:
Interleukin-15 mRNA is expressed by human keratinocytes, Langerhans cells, and blood derived dendritic cells and is downregulated by ultraviolet B radiation.
J Invest Dermatol
106:1047,
1996[Medline]
[Order article via Infotrieve]
10.
Giri JG,
Ahdieh M,
Eisenman J,
Shanebeck K,
Grabstein K,
Kumaki S,
Namen A,
Park LS,
Cosman D,
Anderson D:
Utilization of the beta and gamma chains of the IL-2 receptor by the novel cytokine IL-15.
EMBO J
13:2822,
1994[Medline]
[Order article via Infotrieve]
11.
Giri JG,
Kumaki S,
Ahdieh M,
Friend DJ,
Loomis A,
Shanebeck K,
DuBose R,
Cosman D,
Park LS,
Anderson D:
Identification and cloning of a novel IL-15 binding protein that is structurally related to the alpha chain of the IL-2 receptor.
EMBO J
14:3654,
1995[Medline]
[Order article via Infotrieve]
12.
Kaltoft K,
Bisballe S,
Rasmussen HF,
Thesstrup-Pedersen K,
Thomsen K,
Sterry W:
A continuous T-cell line from a patient with Sézary syndrome.
Arch Dermatol Res
279:293,
1987[Medline]
[Order article via Infotrieve]
13.
participants:
Classification and staging of cutaneous T cell lymphoma (CTCL)
, in Burg G
(ed):
Recommendations for Staging and Therapy of Cutaneous Lymphomas.
Irsee, Germany, EORTC/BMFT Cutaneous Lymphoma Project Group
, 1987
, p 1
14.
Dummer R,
Heald PW,
Nestle FO,
Ludwig E,
Laine E,
Hemmi S:
Burg G: Sézary syndrome T-cell clones display T-helper 2 cytokines and express the accessory factor-1 (interferon- receptor -chain).
Blood
88:1383,
1996[Abstract/Free Full Text]
15.
Gough NM:
Rapid and quantitative preparation of cytoplasmatic RNA from small numbers of cells.
Anal Biochem
173:93,
1988[Medline]
[Order article via Infotrieve]
16.
Döbbeling U,
Böni R,
Häffner A,
Dummer R,
Burg G:
Method for simultaneous RNA and DNA isolation from biopsy material, culture cells, plants and bacteria.
BioTechniques
22:88,
1997 [Medline]
[Order article via Infotrieve]
17.
Namiuchi S,
Kumagai S,
Sano H,
Yodoi J,
Uchiyama T,
Ikai K,
Imura H,
Maeda M:
A human T cell line established from a patient with Sézary syndrome. Application for assay of human interleukin-2 (IL-2).
J Immunol Methods
94:215,
1986[Medline]
[Order article via Infotrieve]
18.
Abrams JT,
Lessin SR,
Ghosh SK,
Nowell PC,
Ju W,
Vonderheid EC,
Rook AH,
DeFreitas E:
Malignant and nonmalignant T cell lines from human T cell lymphotropic virus type I-negative patients with Sézary syndrome.
J Immunol
146:1455,
1991[Abstract]
19.
Meazza R,
Verdiani S,
Biassoni R,
Coppolecchia M,
Gaggero A,
Orengo AM,
Colombo MP,
Azzarone B,
Ferrini S:
Identification of a novel interleukin-15 (IL-15) transcript isoform generated by alternative splicing in human small cell lung cancer cell lines.
Oncogene
12:2187,
1996[Medline]
[Order article via Infotrieve]
20.
O'Connell MA,
Cleere R,
Long A,
O'Neill LAJ,
Kelleher D:
Cellular proliferation and activation of NFkB are induced by autocrine production of tumor necrosis factor a in the human T lymphoma line HUT 78.
J Biol Chem
270:7399,
1995[Abstract/Free Full Text]
21.
Akbar AN,
Borthwick NJ,
Wickremasinghe RG,
Pananyiotidis P,
Pilling D,
Bofill M,
Krajewski S,
Reed JC,
Salmon M:
Interleukin-2 receptor common chain signaling cytokines regulate activated T cell apoptosis in response to growth factor withdrawal: Selective induction of anti-apoptotic (bcl-2, bcl-xL) but not pro-apoptotic (bax, bcl-xS) gene expression.
Eur J Immunol
26:294,
1996[Medline]
[Order article via Infotrieve]
22.
Chae DW,
Nosaka Y,
Strom TB,
Maslinski W:
Distribution of IL-15 receptor alpha chains on human peripheral blood mononuclear cells and effect of immunosuppresive drugs on receptor expression.
J Immunol
157:2813,
1996[Abstract]
23.
McInnes IB,
Al-Mughales J,
Field F,
Leung BP,
Huang F-P,
Dixon R,
Sturrock RD,
Wilkinson PC,
Liew FY:
The role of interleukin-15 in T-cell migration and activation rheumatoid arthritis.
Nat Med
2:175,
1996[Medline]
[Order article via Infotrieve]
24.
Mori A,
Suho M,
Kaminuma O,
Inoue S,
Ohmura T,
Nishizaki Y,
Nagahori T,
Asakura Y,
Hoshino A,
Okamura Y,
Sato G,
Ito K,
Okudaira H:
IL-15 promotes cytokine production of human T helper cells.
J Immunol
56:2400,
1996
25.
Kozak M:
The scanning model for translation, an update.
J Cell Biol
108:229,
1989[Abstract/Free Full Text]
26.
Gazdar AF,
Carney DN,
Bunn PA,
Russell EK,
Jaffe ES,
Schechter GP,
Guccion JG:
Mitogen requirements for the in vitro propagation of cutaneous T-cell lymphomas.
Blood
55:409,
1980[Free Full Text]
27.
Poiesz BJ,
Ruscetti FW,
Gazdar AF,
Bunn PA,
Minna JR,
Gallo RC:
Detection and isolation of C type retrovirus particles from fresh and cultured lymphocytes of a patient with cutaneous T-cell lymphoma.
Proc Natl Acad Sci USA
77:7415,
1980[Abstract/Free Full Text]
28.
Bamford RN,
Battiata AP,
Burton JD,
Sharma H,
Waldmann TA:
Interleukin (IL) 15/IL-T production by the adult T-cell leukaemia cell line HuT-102 is associated with a human T-cell lymphotropic virus type I R region/IL-15 fusion message that lacks many upstream AUGs that normally attenuate IL-15 mRNA translation.
Proc Natl Acad Sci USA
93:2897,
1996[Abstract/Free Full Text]
29.
Onu A,
Pohl T,
Krause H,
Bulfone-Paus S:
Regulation of IL-15 secretion via the leader peptide of two IL-15 isoforms.
J Immunol
158:255,
1997[Abstract]
30.
Tagaya Y,
Kurys G,
Thies TA,
Losi JM,
Azimi N,
Hanover JA,
Bamford RN,
Waldmann TA:
Generation of secretable and nonsecretable interleukin 15 isoforms through alternate usage of signal peptides.
Proc Natl Acad Sci USA
94:14444,
1997[Abstract/Free Full Text]
31.
Sarris AH,
Esgleyes-Ribot T,
Crow M,
Broxmeyer HE,
Karasavvas N,
Pugh W,
Grossman D,
Deissenroth A,
Duvic M:
Cytokine loops involving interferon- and IP-10, a cytokine chemotactic for CD4+ lymphocytes: An explanation for the epidermotropism of cutaneous T-cell lymphoma?
Blood
86:651,
1995[Abstract/Free Full Text]
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Abstract
Introduction
Abstract