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Introduction
Despite its decreasing trend over many decades, gastric
cancer remains a major public health problem worldwide and
accounts for 3%_10% of all cancer-related
deaths[1]. Although adjuvant and neoadjuvant therapy may achieve
moderate response rates, the regimens cannot produce complete
responses in more than 10%_15% of patients, neither can
they extend median survival beyond 1
year[2]. Therefore, it could be considered that most cytotoxic chemotherapies
expose patients to the side-effects of a potentially
ineffective treatment. When assessing the value of anticancer
treatment, it is important to consider the impact on both
survival and quality of life. This is particularly important for
patients with advanced cancer whose life expectancy is short.
The current state of antigastric cancer requires further
investigation of new therapeutic approaches, such as
non-cytotoxic drugs for advanced gastric cancer. The inhibitive
effect of aspirin or rofecoxib, a selective cyclooxygenase
(COX)-2 inhibitor, on the proliferation of gastric cancer has
been reported in our previous study[3]. These non-steroidal
anti-inflammatory drugs (NSAIDs) exert dual function, the
induction of NSAID-activated gene (NAG)-1 expression, and
the inhibition of COX-2[4], which are widely overexpressed in
gastric adenocarcinoma[5,6]. Various studies have
demonstrated that the growth of normal cells and malignant tumors
may be regulated by gut peptides[7,8]. Previous data have
shown that the mean tumor volume in nude mice treated with
octreotide, an analogue of somatostatin (SST), was
significantly lower than that of the control group with an inhibitory
rate of 60.6%[9,10]. The heterogeneity of SST receptors (SSTR)
has been proven during the past decade by the cloning of
different genes coding for SSTR
subtype[11]. However, the positive rate of SSTR and the dominant SSTR subtype in
gastric cancer remains unclear.
Some links between COX-2 and SST, such as
extracellular signal-regulated protein kinase (ERK), a downstream
molecule in the mitogen-activated protein kinase (MAPK)
pathway induced by SSTR binding, have been
indicated[12]. The hypothetically synergistic inhibition of the
combination of 2 types of non-cytotoxic agents, rofecoxib and
octreotide, on the growth of gastric cancer has also been
confirmed in both in vitro and in
vivo animal studies[13]. However, whether this regime could be beneficial for human
gastric cancer treatment is still unknown. To address this
issue, we investigated the effect of celecoxib alone or in
combination with octreotide on the growth of gastric
adenocarcinoma through a prospective, clinical randomized trial.
The molecular targets for celecoxib and octreotide were also
probed to understand the mechanism behind them.
Materials and methods
Patients This prospective study enrolled 75
consecutive patients (male: 46, female: 29; mean age: 55; range:
27_85) with histologically identified gastric adenocarcinoma who
underwent surgery such as total gastrectomy, subtotal
gastrectomy, or the extent of lymphadenectomy from March
2002 to December 2004 in West China Hospital, Sichuan
University (Chengdu, China). The patients were
randomized to receive different treatments before surgery: (i)
celecoxib (Pfizer, New York, NY, USA) 0.2g/d,×7d,
n=25; (ii) celecoxib 0.2 g/d, plus subcutaneous injection of octreotide
(Novartis Pharma, Beijing, China) 100 µg/d, ×7 d,
n=25; and (iii) preoperative treatment without any anticancer medicine
as controls (n=25). No cytotoxic chemotherapy was applied.
The data on gastric endoscopy, abdominal ultrasonography,
magnetic resonance imaging (MRI), or computed
tomography (CT) before the operation were matched as well as
possible to get a parallel TNM stage (the Tumor, Lymph Node,
Metastasis classification) among the three groups. This
study was approved by the ethic committee of our hospital.
All of the patients gave their informed consent for the
preoperative treatments mentioned above.
Immediately after resection, the tissue samples of gastric
adenocarcinoma were obtained from all of patients. One part
of the tumor tissue was used for histological examination,
while the other part was rapidly frozen at -80 °C.
Histopathological examination The tissue samples of
gastric adenocarcinoma were fixed in 10%
phosphate-buffered formalin, embedded in paraffin, and sectioned serially
at a thickness of 4 µm. The tissue sections were deparaffinized
and stained with hematoxylin-eosin (HE). The slides were
examined by an assigned pathologist without knowledge of
the group to which the specimen belonged. The degrees of
tumor necrosis, infiltration of inflammatory cells, and
fibrosis were semiquantitatively assessed in each tumor
according to a 4-point arbitrary scale of + to ++++, that is, + is the
inflammatory response less than 5% area; ++ is 5%_30%
area; +++ is 30%_70% area; and ++++ is more than 70% area.
Apoptosis Terminal deoxynucleotide
transferase-mediated dUTP nick end-labeling (TUNEL)
assay[14] was performed using a commercial kit (Roche, Basel, Switzerland).
The number of apoptotic cells positive for TUNEL staining
was counted in the 10 arbitrary microscopic fields at a
magnification of 400×per section. The apoptotic index was
calculated as follows: apoptotic index (%)=(apoptotic cell
number/total cell number)×100.
Immunohistochemistry for the detection of COX-2 and
microvessel density The tissue sections were deparaffinized
and rehydrated. The specimens were heated in an autoclave
for 9 min at 90 °C for antigen retrieval, immersed in 0.3%
hydrogen peroxide in methanol for 30 min, and then immersed
in normal goat serum for 30 min to block endogenous
peroxidase activity and the unspecific binding sites, respectively.
Then, the tissue sections were incubated with a specific
rabbit polyclonal antibody against human COX-2 (Santa Cruz
Biotechnology, Santa Cruz, CA, USA) in a dilution of 1:100
overnight at 4 °C. The positive reaction was revealed by the
streptavidin-biotin-peroxidase technique. The positive
controls for the reaction were paraffin-embedded sections from
colon carcinomas. Non-immune rabbit serum was used as a
negative control.
COX-2-positive cells were counted from 500 cells on 5
fields at a magnification of 400×, with a 40×objective lens
and a 10×ocular lens of 0.22 mm2 per field. The intensity of
COX-2 staining was graded on a scale of 0_2 (0, negative; 1,
moderate; and 2, strong intensity of staining). The
percentage of stained cells among the total tumor cells were
assessed as 4 grades (0, £5%; 1, 6%_25%; 2, 26%_50%; and 3,
³51%). Furthermore, the tumors defined as COX-2 positive
were semiquantitatively scored as (_) 0_1, (+) 2_3, (++) 4_6,
and (+++) >6 on the basis of the final product of intensity
score time percentage score.
The immunohistochemical visualization of microvessel
density (MVD) was carried out as mentioned above. The
specific antibody against human factor VIII related antigen
was purchased from Zymed (San Francisco, CA, USA). The
microvessels were defined as any factor VIII related antigen
positive endothelial cell or endothelial cell cluster with or
without a visible lumen. The locations where we measured
the MVD were determined according to previous
studies[15,16]. The marginal areas of the largest transect of tumor where the
progressive malignant tissues are found are usually
companied with flourishing angiogenesis. The
microvasculature developed in tumors as an intense network and each
distinct branch was interpreted as a single vessel. Large
sinusoidal vessels were also counted as a single vessel.
Positive controls for the reaction were paraffin-embedded
sections from vessel tissues. Non-immune rabbit serum was
used as a negative control.
Individual microvessels were counted on 5 fields at a
magnification of 400× in a highly vascular tumor area (hot
spot). The microvessel count was performed in the tumor,
excluding areas with prominent hyalinization and necrosis.
The mean of 5 counts was used as the MVD in each case.
Data were expressed as the number of vessels per
mm2.
NAG-1 gene detection by RT-PCR Total RNA was
extracted from tumor tissues using the Tripure RNA isolation
kit (Roche, Basel, Switzerland). The primers (Shanghai
Sangon, Shanghai, China) designed for PCR were according
to the sequences on GeneBank. The sequences of primers
were as follows: NAG-1, sense: 5'-TTGCGGAAACGCTACGAG-3', antisense: 5'-AACAGAGCCCGGTGAAGG-3'; and
GAPDH, sense: 5'-ACCACAGTCCATGCCATCAC-3', antisense: 5'-TCCACCACCCTGTTGCTGTA-3'.
Using the TaKaRa one-step method (TaKaRa, Dalian,
China) for RT-PCR, the reaction system (12.5 µL for the biopsy,
25 µL for the surgery samples) was as follows: 3.75 µL
RNase-free dH2O, 1.25 µL 10×one-step RNA PCR buffer, 1.25 µL (10
mmol/L) dNTP mixture, 2.5 µL (25 mmol/L)
MgCl2, 0.25 µL (40 U/µL) RNase inhibitor, 0.25 µL (5 U/µL) AMV RTase XL, 0.25
µL (5 U/µL) AMV-optimized Taq, 0.5 µL (20 µmol/L) sense
primer, 0.5 µL (20 µmol/L) antisense primer, and 2 µL total
RNA. The reaction conditions were: 55 °C for 30 min; 94 °C
for 2 min; 94 °C for 10 s, 57 °C for 10 s, 72 °C for 10 s, 30
cycles; and 72 °C for 3 min. The amplification products of
NAG-1 and GAPDH were 209 and 452 bp, respectively. The
gray scale integral ratio of NAG-1/GAPDH was regard as the
relative transcription level of NAG-1, and the quantitative
analysis of amplification products was performed by using
the gelatin imaging system (Kodak, Rochester, NY, USA).
Transcription of SSTR-1, SSTR-2, and SSTR-3 in
gastric cancer with real-time fluorescence-quantitative
RT-PCR Total RNA was extracted from tumor tissues using the
Tripure RNA isolation kit (Roche, USA). First-strand cDNA
was produced by Moloney murine leukemia virus reverse
transcriptase (MBI, USA) with 1 µg of total RNA and 0.5 g of
oligo (dT) 18. The GAPDH gene was used as an internal
control. TaqMan (Shanghai Sangon, Shanghai, China)
probe-based real-time fluorescence-quantitative RT-PCR was
used for quantification. PCR was performed in a reaction
system as follows: 1×PCR buffer, 2.5 mmol/L
MgCl2, 0.3 mmol/L dNTP, 2.5 µmol/L each of the upstream and downstream
primers for SSTR-1/GAPDH, SSTR-2/GAPDH, and
SSTR-3/GAPDH, 2.5 µmol/L TaqMan probe, 1.5 U heat-resistant
Taq DNA polymerase, 14.8 µL
ddH2O, and 2.5 µL cDNA. After denaturation for 2 min at 94 °C, PCR was started. One cycle
consisted of a denaturation step for 20 s at 94 °C, an
annealing step for 30 s at 53 °C (gathering fluorescence), and an
extension step for 60 s at 60 °C. After 45 cycles, the values of
cycle threshold for SSTR-1, SSTR-2, SSTR-3, and GAPDH of
all the samples were measured. Using the comparative
threshold method, the relative quantity was calculated, equal to
the Ct of SSTR-1, SSTR-2, or SSTR-3 divided to the Ct of
GAPDH. The sequences of the primers used were as follows:
SSTR-1, sense: 5'-CCACGGTGAGTCAGCTGT-3', antisense:
5'-GAAAGAGCGCTTGAAGTTGTCT-3'; SSTR-2, sense: 5'-CCAGCCCTTAAAGGCATGTT-3', antisense:
5'-CTTGA-CCAAGCAGAGGACA-3'; SSTR-3, sense:
5'-TGCCTTC-TTTGGGCTCTACT-3', antisense:
5'-CTGCTTGAAGCGG-TAGGAGA-3'; GAPDH, sense:
5'-GGGTGTGAACCATGA-GAAGT-3', antisense: 5'-CCAAAGTTGTCATGGATGACCT-3'.
Detection of SSTR-2 in tissue sample with biomolecular
interaction analysis system[17] The tissue samples of
gastric cancer or no-cancer gastric mucosa were broken to pieces
with scissors on ice before the addition of special buffer
(4 µL/mg tissue) supplied by BIAcore AB (Amersham
Biosciences, Uppsala, Sweden) for the extraction of proteins.
Then the samples were homogenized in ice-cold phosphate
buffered solution and centrifuged to pellets. The protein
concentration of the supernatants was measured with Pierce
BCA (bicinchoninic acid) protein assays (Pierce
Biotechno-logy, Rockford, IL, USA), and the supernatants were stored
at -70 oC.
The SSTR-2 antibody was immobilized on BIAcore CM5
sensor chip surface using an amine coupling kit (BIAcore
AB). A biomolecular interaction analysis system (BIAcore
X, Amersham Biosciences, Sweden) was used to measure
the binding capacity between SSTR-2 and its antibody. The
60 µL samples were then injected onto the chip immobilized
with the SSTR-2 antibody at a flow rate of 30 µL/min; the
buffer for the extraction of proteins was used for blank
subtraction. The detection of SSTR-2 was performed in a
BIA (biomolecular interaction analysis) system through
binding_binding/dissociation_washing_regenerations. The raw
data from individual binding experiments were determined
using BIA evaluation software (Amersham Biosciences,
Sweden). The technological fluctuations of the baseline were
±5 resonance units (RU). The data were normalized to
RU/mg protein. Specific binding=total binding-non-specific
binding.
Statistical analysis All the results were expressed as the
mean ± SD and were analyzed by SPSS 11.0 for Windows
software (SPSS, Chicago, IL, USA). Statistical significance
was calculated with one-way ANOVA and
χ2-test. Differences were considered statistically significant at
p<0.05.
The sample size was evaluated with MVD data according
to the following formula, where α=0.05 and β=0.10:
The calculation indicated that the proper sample size
should be at least 23 patients per group and 69 patients in
the 3 groups. The present study enrolled 25 patients into
each group with a strong power of test (1-β=0.90).
Results
TNM staging and histopathological examination of
gastric adenocarcinomas The percentage of TNM stage II, III,
and IV in 75 cases was 13.3%, 45.3%, and 41.3%, respectively.
According to World Health Organization histological
grouping[18], the tumors were divided into the well-differentiation
group (13.3%), moderately-differentiation group (40.0%), and
poor differentiation group (46.7%). The histological types
of gastric adenocarcinomas in this study included papillary,
tubular, mucinous adenocarcinoma, and signet-ring cell
carcinoma.
The scores of tumor necrosis and fibrosis in 75 cases are
listed in Table 1. Compared with the control group, tumor
necrosis in the celecoxib group had no marked change, but it
was significantly increased in the combination group (Table
1, p<0.05). Furthermore, the semiquantitative analysis also
showed an upregulated fibrosis level in the combination
group (Figure 1, p<0.05). The infiltration of inflammatory
cells in each group did not show significant differences. The
tumor differentiation type in the control group did not bear
an obvious relationship to the extent of necrosis or fibrosis
(r=0, p>0.05).
Apoptosis A significantly increased apoptotic rate was
observed in the combination group (p<0.05), but not in
the celecoxib group (Figure 2; Table 2).
MVD FVIII-R Ag-positive endothelial cells or
endothelial cell clusters in the combination group were less than
those in celecoxib or control groups (Figure 3). The data
from semiquantification of MVD per square in the tissue
sections of gastric cancer also showed a significant decrease
in the combination group (p<0.05), while no marked change
was observed in the celecoxib group (Table 2).
COX-2 expression Although the COX-2-positive
staining in the combination or celecoxib groups seemed lighter
than that in the control group (Figure 4), semi-quantification
did not show a significant difference between them (Table 2;
p>0.05).
NAG-1 expression The transcription of NAG-1 was
detected in the gastric carcinomas of each group (Figure 5) and
were upregulated in the celecoxib and combination groups
(p<0.05). Surgery itself did not affect the transcription of
NAG-1 in the tissues of gastric carcinoma.
Transcription of SSTR-1, SSTR-2, and SSTR-3 in
gastric cancer determined by real-time
fluorescence-quantitative RT-PCR The relative transcription levels of SSTR-1,
SSTR-2, and SSTR-3 in gastric adenocarcinomas were
14.86±9.71, 39.08±29.65, and 19.74±16.93, respectively. The
expression of SSTR-2 in gastric adenocarcinoma was
highest among the SSTR subtypes.
Detection of SSTR-2 in gastric tissue The biomolecular
interaction analysis system revealed that SSTR-2 proteins in
gastric cancer before surgery were greatly higher than that
either in gastric mucosa or in surgical specimens of gastric
cancer (p<0.01). However, after surgery, the expression of
SSTR-2 in celecoxib group was significantly higher than that
of control group (p<0.05). The addition of octreotide before
surgery did not seem to enhance SSTR-2 expression
comparing with celecoxib group (Table 3, p>0.05). No
relationship between the expression of SSTR-2 and the
differentiation of gastric carcinomas was observed. However, more
necrosis and fibrosis were found in the SSTR-2-positive
tumors than in the SSTR-2-negative ones treated with
celecoxib and octreotide (Table 4).
Adverse events of treatment During the study, no
severe adverse events, such as gastrointestinal bleeding,
perforation, diarrhea, and cardiovascular events, were
recorded in the treatment groups. There were also no notable
increases of alanine aminotransferase or aspartate
aminotransferase (approximately 3 or more times the upper limit of normal)
reported. The preoperative administration of celecoxib and
octreotide did not result in increased bleeding in
gastrectomy and retard of wound healing.
Although more necrosis lesions were found in the
combination group, the patients did not present fever,
abdominal pain, or massive upper gastrointestinal bleeding.
Discussion
The inhibitive effects of the combination of
non-cytotoxic drugs (COX-2 inhibitor and SST analogue) on gastric
cancer in vitro or in vivo have been reported in animal
experiments[9,13]. In the present study, more necrosis was
detected in gastric adenocarcinomas of patients treated with
celecoxib and octreotide for 1 week. Well-matched tumor
stage among the three groups suggested that these
histopathological changes might not be due to the unbalance of
tumor size among the groups. Usually the poorly
differentiated gastric adenocarcinomas may present more necrosis
because of unparallel angiogenesis to flourishing tumor cells.
However, the higher score of necrosis was presented in the
combination group with well or moderate differentiated
gastric adenocarcinomas. It indicated an inhibitive effect of the
combination of two non-cytotoxic drugs on the tumors. The
proliferation and infiltration of tumor cells rely on the
development of blood vessels of
tumors[19]. Celecoxib combined with octreotide significantly decrease the
MVD of the tumors.It might be the cause of necrosis lesions described above.
In addition, the fibrosis of tumors was scant in either the
control or celecoxib groups, but was extensively increased
in the combination group. This significant difference
between the groups might suggest the effect of treatment with
celecoxib and octreotide. It is unclear whether or not it could
be regarded as a consequence of massive necrosis or a
direct reaction to the combination treatment. Moreover, it has
been observed that the desmoplastic reaction in gastric
adenocarcinomas may vary with the tumors from scant to
abundant but with unclear mechanisms[20]
. It was impossible to enroll patients according to the extension of stroma before
the surgery due to limited biopsies. Therefore, more fibrosis
in the combination group still could not exclude the result of
unparallel grouping on the extension of stroma before the
operation.
The growth characteristics of tumor cells consist of
unlimited proliferation, imbalance between generation and
apoptosis of cells, and the ability of
invasion[21].The apoptotic rate of gastric adenocarcinoma cells was
significantly increased in the combination group by which the
growth of gastric cancer would be arrested efficiently in a
peaceful way.
The effects of celecoxib on human gastric
adenocarcinomas tentatively suggested that COX-2 might be the target of
celecoxib. However, COX-2 expression in tumors in the
combination or celecoxib groups did not decrease when
compared with the control group. NAG-1, a non-COX-2 pathway,
is considered a downstream target protein of early growth
response-1 gene with an inhibitive ability against
cancer[22]. It was obviously upregulated in the human gastric
adenocarcinomas treated with celecoxib in this study. Therefore,
the inhibitive effects of celecoxib on the growth of gastric
cancer were mediated through increasing NAG-1.
It has been reported that the expression of SSTR-3 was
significantly lower in gastric cancer when compared with
normal mucosa[23]. In the present study, although mRNA for
SSTR-1, SSTR-2, and SSTR-3 were detected in the tissues of
gastric adenocarcinomas, the quantity of SSTR-2 mRNA was
the highest. Based on this result, the SSTR-2 protein
measured by the biomolecular interaction analysis system was
compared among the 3 groups. Both the positive rate and
quantity of SSTR-2 in the biopsy specimens of gastric
cancer were significantly higher than those in the biopsy
specimens of gastric mucosa with superficial gastritis.
Theoretically, all of gastric mucosa should be SSTR-2
positive. The low positive rate and quantity of SSTR-2 in
the biopsy specimens of gastric mucosa of the present study
may be related to superficial biopsy without including
enough gastric crypts where SSTR-2 is located intensively.
Therefore, it is still difficult to decide whether the SSTR-2
protein was really increased in the malignant tissues. Even
though, this result indicated that only about one-third of
patients with gastric cancer have molecule targets for the
direct effect of octreotide.
The surgical removal of gastric cancer was very crucial
to the treatment. However, the SSTR-2 protein in the
surgical specimens of gastric cancer was greatly lower than that
in the pre-operation specimens of gastric cancer. It meant
that the operation itself might mask the expression of the
SSTR-2 protein which might be a negative control of cancer
cell growth, bringing easy proliferation and metastasis of
tumors. Interestingly, celecoxib presented the ability to
induce the expression of the SSTR-2 protein in gastric cancer
in this study. It was helpful for octreotide to target the
cancer cells. The pre-operation treatment with celecoxib plus
octreotide for the patients with gastric cancer may be a
valuable recommendation.
In this study, we also found that octreotide could partly
inhibit the proliferation of SSTR-negative neoplasms. These
results suggest that octreotide may indirectly affect tumor
growth through the inhibition of release of some peptides or
growth factors such as insulin, epidermal growth factor, and
insulin-like growth factor-1, which promote tumor
proliferation[24]. Beside the synergic antitumor mechanisms
discussed above, both the COX-2 inhibitor and octreotide also
could inhibit the intracellular mitogen-activated protein
kinase signaling pathways, and therefore, their combination
in a regime may greatly suppress the synthesis of DNA in
tumor cells[25,26].
COX catalyzes the initial step of arachidonic acid
metabolism and prostaglandin production. COX activity has
been found to be associated with 2 distinct isoenzymes:
COX-1 and COX-2. COX-1 was hypothesized to be involved in the
protection of gastric mucosa and the maintenance of
hemostasis, whereas COX-2 was thought to be involved in
pathophysiological processes, such as inflammation and the
proliferation of cells[27]. Whole-blood assays for celecoxib
have shown COX-2/COX-1 selectivity ratios as
7.6[28]. The possible injury of mucosal defense caused by celecoxib was
expected to be diminished by octreotide with which the
output of gastric acid is able to be inhibited through the
mediation of SSTR in parietal cells of gastric mucosa. Interestingly,
the present regime displayed a substantial anti-proliferation
of gastric cancer without severe adverse events owing to
the synergic actions on both the curative and side-effects.
Several studies have demonstrated that patients with
gastric adenocarcinomas receiving preoperative
chemotherapy had a downstaging of tumor size and an increase in
rates of curative resection. Nevertheless, the overall
survival has not been prolonged. In addition, the
implementation of that treatment has posed several problems with
respect to the toxicity of the treatment, depression of
anti-tumor immune, and a high rate of locoregional
recurrence[29,30]. This prospective study suggested that the combination of
celecoxib and octreotide resulted in the up-regulation of
anticancer approaches, including NAG-1 and SSTR-2 and a
substantial pathological response in patients with gastric
cancer. As the non-cytotoxic agents, celecoxib combined
with octreotide was well-tolerated and safe when followed
by gastrectomy. This strategy is worthy of further clinical
trials to evaluate its benefit on the rates of curative resection
and relapse on overall survival.
References
1 Dicken BJ, Bigam DL, Cass C, Mackey JR, Joy AA, Hamilton
SM. Gastric adenocarcinoma: review and considerations for
future directions. Ann Surg 2005; 241: 27_39.
2 Wohrer SS, Raderer M, Hejna M. Palliative chemotherapy for
advanced gastric cancer. Ann Oncol 2004; 15: 1585_95.
3 Liu CL, Tang CW, Wang CH, Zhou XC. The effects of selective
cyclooxygenase-2 inhibitors on the growth of gastric
adeno-carcinoma. J West China Univ Med Sci 2003; 3: 372_5. Chinese.
4 Baek SJ, Wilson LC, Lee CH, Eling TE. Dual function of
nonsteroidal anti-inflammatory drugs (NSAIDs): inhibition of
cyclo-oxygenase and induction of NSAID-activated gene. J Pharmacol
Exp Ther 2002; 301:1126_31.
5 Uefuji K, Ichikura T, Mochizuki H. Expression of
cyclo-oxygenase-2 in human gastric adenomas and adenocarcinomas. J Surg
Oncol 2001; 76: 26_30.
6 Ohno R, Yoshinaga K, Fujita T, Hasegawa K, Iseki H, Tsunozaki
H, et al. Depth of invasion parallels increased
cyclooxygenase-2 levels in patients with gastric carcinoma. Cancer 2001; 91:
1876_81.
7 Maoret JJ, Anini Y, Rouyer-Fessard C, Gully D, Laburthe M.
Neurotensin and a non-peptide neurotensin receptor antagonist
control human colon cancer cell growth in cell culture and in
cells xenografted into nude mice. Int J Cancer 1999; 80: 448_54.
8 Pollak MN, Schally AV. Mechanisms of antineoplastic action of
somatostatin analogs. Proc Soc Exp Biol Med 1998; 217:
143_52.
9 Tang C, Wang C, Tang L. Effects of combined octreotide and
aspirin on the growth of gastric cancer. Chin Med J (Engl) 2003;
116: 373_7.
10 Pinski J, Halmos G, Yano T, Szepeshazi K, Qin Y, Ertl
T, et al. Inhibition of growth of MKN45 human gastric-carcinoma
xenografts in nude mice by treatment with
bombesin/gastrin-releasing-peptide antagonist (RC-3095) and somatostatin
analogue RC-160. Int J Cancer 1994; 57: 574_80.
11 Reisine T , Bell GI. Molecular biology of somatostatin receptors.
Endocr Rev 1995; 16: 427_42.
12 Kwon KS, Chae HJ. Sodium salicylate inhibits expression of
COX-2 through suppression of ERK and subsequent NF-kappaB
activation in rat ventricular cardiomyocytes. Arch Pharm Res
2003; 26: 545_53.
13 Tang CW, Liu CL, Zhou XC, Wang CH. Enhanced inhibitive
effects of combination of rofecoxib and octreotide on the growth
of human gastric cancer. Int J Cancer 2004; 112: 470_4.
14 Gavrieli Y, Sherman Y, Beb-Sasson SA. Identification of
programmed cell death in situ via specific labeling of nuclear DNA
fragmentation. J Cell Biol 1992; 119: 493_501.
15 Hasan J, Byers R, Jayson GC. Intra-tumoural microvessel
density in human solid tumours. Br J Cancer 2002; 86: 1566_77.
16 Dhar DK, Wang TC, Tabara H, Tonomoto Y, Maruyama R,
Tachibana M, et al. Expression of trefoil factor family members
correlates with patient prognosis and neoangiogenesis. Clin
Cancer Res 2005; 11: 6472_8.
17 Casper D, Bukhtiyarova M, Springman EB. A Biacore biosensor
method for detailed kinetic binding analysis of small molecule
inhibitors of p38alpha mitogen-activated protein kinase. Anal
Biochem 2004; 325: 126_36.
18 Sarbia M, Becker KF, Hofler H. Pathology of upper
gastrointestinal malignancies. Semin Oncol 2004; 31: 465_75.
19 Jazowiecka-Rakus J, Jarosz M, Kozlowska D, Sochanik A, Szala
S. Combination of vasostatin and cyclophosphamide in the
therapy of murine melanoma tumors. Acta Biochim Pol 2007;
54: 125_33.
20 Japanese Gastric Cancer Association. Japanese Classification of
Gastric Carcinoma __ 2nd English Edition. Gastric Cancer 1998;
1: 10_24.
21 Diasio RB, Fourie J. Targeting the epidermal growth factor
receptor in the treatment of colorectal cancer: state of the art.
Drugs 2006; 66:1441_63.
22 Baek SJ, Kim JS, Moore SM, Lee SH, Martinez J, Eling TE.
Cyclooxygenase inhibitors induce the expression of the tumor
suppressor gene EGR-1, which results in the up-regulation of
NAG-1, an antitumorigenic protein. Mol Pharmacol 2005; 67:
356_64.
23 Hu C, Yi C, Hao Z, Cao S, Li H, Shao
X, et al. The effect of somatostatin and SSTR3 on proliferation and apoptosis of
gastric cancer cells. Cancer Biol Ther 2004; 3: 726_30.
24 Kouroumalis EA. Octreotide for cancer of the liver and biliary
tree. Chemotherapy 2001; 47 Suppl 2: 150_61.
25 Wang CH, Tang CW, Liu CL, Tang LP. Inhibitory effect of
octreotide on gastric cancer growth via MAPK pathway. World
J Gastroenterol 2003; 9: 1904_8.
26 liu c, tang c, zhou x, wang c. Enhanced inhibitive effects of
combination of rofecoxib and octreotide on the growth of
human gastric cancer. Basic Med Sci Clin 2004; 24: 277_81. Chinese.
27 Gajraj NM. Cyclooxygenase-2 inhibitors. Anesth Analg 2003;
96: 1720_38.
28 Riendeau D, Percival MD, Brideau C, Charleson S, Dube D, Ethier
D, et al. Etoricoxib (MK-0663): preclinical profile and
comparison with other agents that selectively inhibit
cyclooxygenase-2. J Pharmacol Exp Ther 2001; 296: 558_66.
29 Macdonald JS. Clinical overview: adjuvant therapy of
gastrointestinal cancer. Cancer Chemother Pharmacol 2004; 54 Suppl 1:
S4_11.
30 Lindsey H. Preoperative chemoradiotherapy shows promise in
gastric cancer. Lancet Oncol 2004; 5: 519.
|
