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Hypoxia Response Element VEGF Cascade Differentially Regulates Vascular Response and Growth Rate in Tumors1
Edwin L. Steele Laboratory, Department of Radiation Oncology, Massachusetts General Hospital, and Harvard Medical School, Boston, Massachusetts 02114 [Y. T., D. F., C. K., R. K. J.], and Center for Transgene Technology and Gene Therapy, Flanders Interuniversity Institute for Biotechnology, KU Leuven, B3000 Belgium [B. O., P. C.]
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ABSTRACT |
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50% of VEGF compared with the WT tumors, suggesting
significant contribution of host stromal cells. To discern the
hypoxia-induced hypoxia inducible factor (HIF)-1
hypoxia
response element (HRE) VEGF signaling cascade, we also examined
tumors derived from HIF-1-/- and HRE-/-
ES cells. As expected, the VEGF protein level in
HIF-1-/- ES tumors was intermediate between
VEGF-/- and WT ES cell tumors. Surprisingly,
HRE-/- ES tumors produced the same level of VEGF as
the VEGF-/- ES tumors, suggesting a critical role of HRE
in tumor cell VEGF production. Angiogenesis in these tumors was
proportional to their VEGF levels (VEGF-/- 
HRE-/- < HIF-1-/- < WT). In contrast, vascular
permeability, leukocyte-endothelial adhesion, and tumor growth were
reduced in VEGF-/- and HRE-/- tumors but
were comparable in HIF-1-/- and WT tumors. This
discrepancy suggests that different intracellular signaling pathways
may be involved in each of these functions of VEGF. More importantly,
these data suggest that host cells are active players in tumor
angiogenesis and growth and need to be taken into account in the design
of any therapeutic strategy. |
Introduction |
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TopABSTRACTIntroductionMaterials and MethodsResults and DiscussionREFERENCES |
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expression, which then mediates a series of
transcriptional responses. The cognate DNA recognition site of HIF-1
is HRE (2
, 5)
. HIF-1 binds to HRE of target genes such
as VEGF, erythropoietin, and glycolytic enzymes. The binding
of HIF-1 to HRE in the VEGF promoter is a predominant
enhancer of VEGF production (5)
. VEGF protein binds to
VEGF receptors on endothelial cells, and these mediate its
physiological functions. We have shown recently that VEGF can be
produced by both cancer cells and host-stromal cells in a tumor
(6)
. However, the relative contribution of these different
cell types to tumor-VEGF and the resulting vascular response have not
been quantitated to date. A variety of genetic and pharmacological strategies have been used to test the causal relationships between VEGF and its putative physiological functions. These include overexpression of VEGF in host cells (7) or neoplastic cells (8) ; targeted deletion of VEGF gene (5 , 9, 10, 11) ; introduction of sense or antisense VEGF gene constructs into neoplastic cells (12 , 13) ; superfusion with recombinant VEGF (14) ; incorporation of VEGF in a gel (15) ; treatment with anti-VEGF antibody (16) ; and modulation of VEGF expression by oncogene, hormone (17) , or other microenvironmental factors (2 , 3) . All of these approaches have collectively provided powerful insight into the role of VEGF in angiogenesis, vascular permeability, leukocyte rolling and adhesion, and tumor growth. However, none of these studies have simultaneously measured all of these parameters in the same tissue at different levels of host versus tumor VEGF. Therefore, the relative dependence of these functions on VEGF levels is unknown. An answer to this important question requires tumors that have controlled VEGF levels and the techniques to simultaneously monitor and quantify all of these parameters in vivo.
In this study, VEGF levels in ES cells were differentially
modulated by targeted deletion of three members of the hypoxia VEGF
cascade: HIF-1, HRE of the VEGF, and
VEGF. VEGF expression in the resulting ES cells in
culture varied as follows: WT (HIF-1+/+
HRE+/+
VEGF+/+) > HIF-1-/-
HRE-/- > VEGF-/- = 0. Using tumors derived
from these ES cells expressing decreasing levels of VEGF and using
intravital microscopy to measure vascular parameters noninvasively and
continuously, we show that different VEGF functions such as
angiogenesis, vascular permeability, and L/E interaction have distinct
VEGF dose dependencies. In addition, VEGF levels in the resulting
tumors showed that host cells in VEGF-/- tumors
produced significant amount of VEGF (50% of WT tumor), and that HRE,
but not HIF-1 deletion, abrogates VEGF production by ES cells
in vivo.
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Materials and Methods |
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TopABSTRACTIntroductionMaterials and MethodsResults and DiscussionREFERENCES |
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-/- ES cells were generated by targeted
deletion as described previously (10
, 18)
5
. ES clones with a randomly integrated gene targeting vector, which
survived high G418 selection, were used as WT controls
(VEGF+/+, HRE+/+, and
HIF-1+/+, respectively).
Animal and Tumor Models.
Mutant or WT cells (2 x 105
cells) were implanted into dorsal skinfold chambers in SCID mice (6–8
weeks of age; 25–35 g) as described previously (18
, 19)
.
Chambers were checked for tumor growth every other day. Twelve to 14
days after cell implantation, macroscopically visible tumors were
observed in the chambers. Measurements of angiogenesis, hemodynamics,
vascular permeability, and L/E interaction were performed 16–26 days
after implantation in size-matched tumors.
Measurement of Tumor Growth.
The tumor-bearing chambers of unanesthetized mice were placed in a
polycarbonate tube and observed by intravital microscopy (Axioplan;
Zeiss, Oberkochen, Germany; Ref. 19
). After capturing an
image of the tumor, its surface area was calculated as 
x a x b (a and
b are major and minor axes). The thickness of the tumors,
c, was measured by a caliper, and the volume was calculated
as /6 x a x b x c. These measurements were
made on days 7, 14, 21, and 28 in at least five animals/group.
Measurements of Angiogenesis and Hemodynamics.
Animals bearing tumors in the dorsal chambers were anesthetized by s.c.
injection of a mixture of 75 mg of ketamine hydrochloride (Parke-Davis,
Morris Plains, NJ) and 25 mg of xylazine (Fermetia, Kansas City, MO)
per kg body weight and observed by intravital microscopy
(19)
. For measurement of RBC velocity and vessel
diameters, 10 mg/ml FITC-labeled dextran solution
(Mr 2,000,000; Sigma Chemical Co., St.
Louis, MO) was injected i.v. via a tail vein cannula to illuminate
blood vessels. Epi-illumination was performed using a 100-W mercury
lamp equipped with a fluorescence filter for FITC (excitation, 525–555
nm; emission, 580–635 nm). An intensified charge-coupled device video
camera (C2400–88; Hamamatsu Photonics K.K., Hamamatsu, Japan) was used
to visualize microvessels in five random areas of each tumor.
Functional vascular density (an index of angiogenesis) was measured as
the total length of perfused vessels per unit area of observation field
(19)
. RBC velocity was measured by the four-slit method
(Microflow system, model 208C, videophotometer version; IPM, San Diego,
CA; Ref. 19
). Vessel diameter was measured by an
image-shearing device (digital video image shearing monitor, model 908;
IPM; Ref. 19
). Vascular volume density of perfused vessels
per unit area was calculated from vascular density and vessel diameter.
Mean blood flow rates and shear rates of individual vessels were
calculated using vessel diameter and mean RBC velocity as described
previously (19)
.
Microvascular Permeability Measurement.
Mice were injected with a bolus (100 µl) of 1%
tetramethylrhodamine-labeled BSA (Molecular Probes, Eugene, OR) in
saline via the tail vein. Fluorescence intensity of the tumor tissue
was measured every 2 min for a total of 20 min by a photomultiplier in
a well-perfused area using a x20 objective lens. The microvascular
permeability to albumin was then calculated as described previously
(16)
.
L/E Interaction Measurements.
Leukocyte rolling and adhesion in tumor vessels were measured as
described previously (20)
. Briefly, mice were injected
with a bolus (20 µl) of 0.1% rhodamine 6-G (Molecular Probes) in
saline via the tail vein to facilitate visualization of leukocytes. One
hundred µm of nonbranching segments with diameters ranging between 13
and 30 µm were selected for the measurements. The number of rolling
(Nr) and adhering (Na) leukocytes, and total
leukocyte flux (Nt) in 30 s was measured. Leukocyte
rolling (%) count was calculated as 100 x Nr/Nt. The density of adhering leukocytes
(cells/mm2) was calculated as
106
x Na/( x D x 100 µm), where D is
the diameter of a given vessel.
ELISA for VEGF in ES Cell Culture and Tumor Tissue.
ES cells were cultured in DMEM supplemented with 10% FCS (Progen
Industries Ltd., Brisbane, Australia) and 500 units/ml leukemia
inhibitory factor (ESGRO; Life Technologies, Inc., Rockville, MD). The
supernatant of ES cell culture medium exposed to both normoxia and
hypoxia (20 and 1% oxygen, respectively) for 24 h was collected.
Measurements were made on samples collected from at least three
different dishes. To determine tissue VEGF levels, tumors were excised
from the dorsal skinfold chambers and frozen in liquid nitrogen. The
tissues were homogenized, and the protein was extracted with 50
mM Tris-HCl buffer (1 ml, pH 7.4) containing 0.25% Triton
X-100, 0.5 M EDTA, 0.1% NP40, and protease inhibitor
mixture (Complete protease inhibitors; Roche Biochemicals,
Indianapolis, IN). The total protein level in each group was determined
by a standard protein assay. The tissue extracts were diluted with 50
mM Tris-HCl to yield samples with the same protein
concentration. Fifty µl of each sample were used to determine VEGF
levels. Immunoreactive VEGF was quantified using a sandwich ELISA
(Quantikine M Mouse VEGF Immunoassay kit; R & D System, Minneapolis,
MN) according to the manufacturer’s recommended protocol.
Statistics.
Results are presented as mean ± SE. Values of different
genotypes of ES cell-derived tumors were compared using a Mann-Whitney
U test (StatView; Abacus, Berkeley, CA). Significance was
assumed at P < 0.05.
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Results and Discussion |
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TopABSTRACTIntroductionMaterials and MethodsResults and DiscussionREFERENCES |
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gene knocked out are embryonic lethal on day
E8.5 to E9, and thus, it is difficult to study angiogenesis and
physiological functions in adult tissue. On the other hand, ES cells
have the capacity to form teratomas when implanted into immunodeficient
mice (Fig. 1)
. These ES cells were used to determine the effect of complete and
partial deletion of VEGF expression on vascular response and solid
tumor formation in vivo.
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200 pg/mg protein (Table 1)
in contrast to undetectable7
levels in the supernatant of
VEGF-/- ES cell cultures. Host stromal cells in
VEGF-/- ES tumors produce VEGF protein 50%
of that in WT tumors. Although we recognize the possibility that the
anti-VEGF antibody used in
ELISA8
detects nonspecific
proteins in the tissue and the contribution of host cells may vary in
different tumors, these findings support the importance of the
production of angiogenic growth factors by host cells in tumor
angiogenesis.
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-/-
cells (normoxia, 67 ± 16; hypoxia, 42 ± 10 pg/ml) and HRE-/- cells (normoxia,
38 ± 14; hypoxia, 43 ± 15 pg/ml) as
compared with WT cells (normoxia, 203 ± 32; hypoxia,
312 ± 32 pg/ml), both under normoxia and hypoxia,
respectively. In fact, hypoxia-induced VEGF up-regulation was
completely abolished in HIF-1-/- and
HRE-/- ES cells in culture. Although a similar
pattern was observed in ES cell-derived teratomas, VEGF protein levels
in HRE-/- tumors are comparable with
VEGF-/- tumors (Table 1)
. These data suggest
that hypoxia-driven signaling of the
HIF-1-/--HRE pathway plays a predominant
role in the induction of VEGF in these tumor tissues.
Although ES cells were incapable of inducing VEGF under
hypoxia in vitro in the absence of HIF-1, other
members of HIF families, such as HIF-2/EPAS, also bind to HRE and thus
can mediate hypoxia-induced gene expression in vivo
(5)
. Our data suggest redundancy in hypoxia-inducible
transcriptional factors but not in the responsive element in the
VEGF promoter in vivo.
Angiogenesis Is Proportional to Tissue Levels of VEGF.
We investigated the dose dependency of angiogenesis on VEGF using
tumors expressing different levels of VEGF. Vascular density
and diameter were analyzed from digitized FITC fluorescence images of
angiogenic vessels (Fig. 1)
. Loss of HIF-1 impaired angiogenesis, as
exhibited by reduced tumor vascular density and diameter compared with
WT tumors (Figs. 1
and 2
; Table 1
). VEGF-/- and
HRE-/- tumors exhibited a further decrease in
vascular density. Collectively, angiogenesis followed a trend similar
to VEGF levels in vivo such that
VEGF-/- HRE-/- < HIF-1-/- < WT. Our
current data, coupled with the existing data from the literature
(1
, 3
, 8
, 12
, 13
, 16)
, indicate that tumor angiogenesis
increases in a dose-dependent manner in response to endogenous tumor
VEGF production.
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,
HRE, or VEGF did not significantly change the mean centerline RBC
velocity in the perfused vessels (Fig. 2
; Table 1
). Reduced vessel diameters and equivalent RBC velocities in
HIF-1-/-, HRE-/-,
and VEGF-/- tumors compared with WT tumors
resulted in decreased blood flow rates and increased shear rates.
Overall tissue perfusion was further reduced in
HIF-1-/-, HRE-/-,
and VEGF-/- tumors relative to WT tumors
because of the reduction in blood flow rates in individual vessels and
vessel density in tissue. Thus, tissue perfusion of ES cell-derived
tumors varied as follows: WT (HIF-1+/+
HRE+/+
VEGF+/+) > HIF-1-/- > HRE-/- VEGF-/-.
Vascular Permeability Is Not Reduced in HIF-1-/-
Tumors Despite Decreased VEGF Level.
Vascular permeability to albumin was approximately the same in WT and
HIF-1-/- tumors (Fig. 2
; Table 1
). In
contrast, VEGF-/- and
HRE-/- tumors exhibited significantly reduced
vascular permeability compared with HIF-1-/-
and WT tumors. These findings are consistent with our recent
measurement of vascular permeability to albumin in normal and tumor
vessels at various doses of exogenous human VEGF (14)
.
Dose-dependent increases in vascular permeability were observed in
normal vessels up to 100 ng/ml VEGF, and no further increases were
observed between concentrations of 100 and 1000 ng/ml VEGF. On the
other hand, vascular permeability of LS174T human colon carcinoma
xenografts was significantly higher than permeability in normal tissue,
and exogenous VEGF (10–1000 ng/ml) did not alter the tumor vascular
permeability. We also found that inhibition of endogenous VEGF in the
same tumor resulted in a significant decrease in vascular permeability
(16)
. Taken together, these findings suggest that vascular
permeability reaches a plateau at a certain VEGF level in both normal
tissue and tumor tissue.
L/E Interaction Is Reduced Only in the Tumors with Lowest VEGF
Level.
We reported that VEGF in tumor interstitial fluid increases
intercellular adhesion molecule-1, vascular cell adhesion molecule-1,
and E-selectin expression in human umbilical vein endothelial cells
(4)
. Furthermore, transgenic mice overexpressing VEGF
under the control of the K14 promoter showed increased L/E interaction
and angiogenesis in vivo (7)
. In the present
study, we found that L/E interaction was approximately the same in WT
and HIF-1-/- tumors. In contrast,
VEGF-/- and HRE-/-
tumors exhibited significantly reduced L/E interactions compared with
HIF-1-/- and WT tumors (Fig. 2)
. These
findings suggest that L/E interaction reaches a plateau at a certain
tissue VEGF level similar to vascular permeability and support the link
between angiogenesis and L/E interaction (25)
.
Growth Rate of HIF-1-/- Tumors Is Comparable with
WT Tumors Despite Reduced Angiogenesis.
One week after implantation of these ES cells, a red spot was observed
in chambers in all genotypes, suggesting a host inflammatory response.
At 12–14 days after implantation, ES cell implants developed into
tumors with different growth rates, depending on the genotype (Fig. 3)
. HIF-1-/- tumors grew at the same rate as
WT tumors for 4 weeks after cell implantation, the end point of this
study. Both WT and HIF-1-/- tumors reached a
size of 75 mm2 in area and 120
mm3 in volume between 21 and 28 days, at which
point they filled the entire dorsal skin windows. This is consistent
with our previous finding that HIF-1 mediates apoptosis by inducing
p53 (18)
. In contrast, both HRE-/-
and VEGF-/- tumors grew at a significantly
slower rate than WT and HIF-1-/- tumors in
both area and volume. The growth rate of HRE-/-
tumors analyzed by volume was between WT and
HIF-1-/- tumors and
VEGF-/- tumors during the observation period
(Fig. 3)
. Collectively, these data suggest that prediction of tumor
growth rate on the basis of VEGF levels or angiogenesis alone is
simplistic and must take into account other molecules/parameters that
govern proliferation and apoptosis of cells.
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mutation studies showed somewhat different
responses (18
, 26
, 27)
; and (c)
post-transcriptional regulation is as important as transcriptional
regulation in many genes such as VEGF for mRNA stability. Targeted gene
deletion strategy may not address posttranscriptional regulation.
Despite these limitations, our study suggests that stepwise
manipulation of the HIF-1 HRE VEGF signaling cascade
differentially impacts angiogenesis, vascular permeability, and L/E
interaction. Different signaling pathways may be involved in these
different functions of VEGF. The binding of HIF-1 to HRE in the
VEGF promoter is a major pathway that leads to the induction
of VEGF, contributing to its physiological function in
tumors. The deletion of the VEGF gene in tumor cells did not
completely block tumor VEGF production, angiogenesis, or tumor growth.
Thus, host-derived VEGF may be enough to maintain angiogenesis and
tumor growth albeit at slower rate. This finding has significant
implications for various antiangiogenic therapies for solid tumors
(28)
.
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ACKNOWLEDGMENTS |
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FOOTNOTES |
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1 Supported by Outstanding Investigator Grant
R35-CA56591 from National Cancer Institute (to R. K. J.) and a grant
from the Alexander and Margaret Stewart Trust (to D. F.). This work
was presented at 91st Annual Meeting of the American Association for
Cancer Research, April 1–5, 2000, San Francisco. 
2 These two authors contributed equally to this
work.
3 To whom requests for reprints should be
addressed, at Department of Radiation Oncology, Massachusetts General
Hospital, 100 Blossom Street, COX-7, Boston, MA 02114. Phone:
(617) 726-4083; Fax: (617) 726-4172; E-mail: jain{at}steele.mgh.harvard.edu
4 The abbreviations used are: VEGF, vascular
endothelial growth factor; ES, embryonic stem; L/E,
leukocyte-endothelial; HIF, hypoxia-inducible factor; HRE, hypoxia
response element; WT, wild type; SCID, severe combined
immunodeficient.
5 B. Oosthuyse, L. Moons, H. Beck, J. V. Dorpe, P.
Hellings, M. Gorselink, D. Nuyens, S. Heymans, G. Theilmeier, M.
Dewerchin, V. Laudenbach, P. Vermylen, T. Acker, A. Damert, N. Cashman,
H. Fujisawa, M. R. Drost, W. Robberecht, R. Sciot, F. Bruyninckx, P.
Gressens, K. H. Plate, F. Lupu, J. M. Herbert, D. Collen, and P.
Carmeliet. Targeted deletion of the hypoxia response element in
the VEGF promoter causes adult motor neuron
degeneration, submitted for publication.
6 Thirty to 50% of HRE-/- mice
survive for more than a year after birth and develop motor neuron
defects (see footnote 5).
7 Detection limit of VEGF ELISA was 7.8 pg/ml.
8 Murine VEGF ELISA kit from R&D does not
cross-react with murine placental growth factor.
Received 6/26/00. Accepted 9/11/00.
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REFERENCES |
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|
TopABSTRACTIntroductionMaterials and MethodsResults and DiscussionREFERENCES |
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in hypoxia-mediated apoptosis, cell proliferation and tumour angiogenesis. Nature (Lond.), 394: 485-490, 1998.[Medline]
-induced leukocyte adhesion in normal and tumor vessels: effect of tumor type, transplantation site, and host strain. Cancer Res., 55: 4824-4829, 1995. is required for solid tumor formation and embryonic vascularization. EMBO J., 17: 3005-3015, 1998.[Medline]
is a positive factor in solid tumor growth. Cancer Res., 60: 4010-4015, 2000.This article has been cited by other articles:
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|
|
|
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|
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|
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|
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A. Kadambi, C. Mouta Carreira, C.-o. Yun, T. P. Padera, D. E. J. G. J. Dolmans, P. Carmeliet, D. Fukumura, and R. K. Jain Vascular Endothelial Growth Factor (VEGF)-C Differentially Affects Tumor Vascular Function and Leukocyte Recruitment: Role of VEGF-Receptor 2 and Host VEGF-A Cancer Res., March 1, 2001; 61(6): 2404 - 2408. [Abstract] [Full Text]
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, P < 0.05 as compared with HRE-/- tumors.
Bars, SE.