Cancer Letters, 61 (1991)
61-
66
61
Elsevier Scientific Publishers Ireland Ltd.
Effects of 3-aminobenzamide on the post-initiation phase of Nnitrosobis(Zoxopropy1) amine induced pancreatic carcinogenesis in Syrian hamsters K. Mizumotob,
T. Tsujiuchia,
M. Tsutsumia,
A. Dendaa,
T. Amanumaa,
S. Kondoh”
and
Y. Konishi” ‘Department and
of Oncological
bDepartment
Pathology,
of Surgery
I, Kyushu
Cancer
Center,
Uniuersity.
Sara
Faculty
Medical
of Medicine,
College. 3-1-1,
840
Shijo-cho.
Maidashi,
Koshihara,
Higashi-ku,
Naro
Fukuoko
634
812
(Japan) (Received
25 April 1991)
(Revision
received
(Accepted
29 July
10 September
1991) 1991)
Summary Effects
of
3-aminobenzamide
pancreatic carcinogenesis nitrosobis(Z-oxopropyl)amine
after
(ABA) initiation
on
by Nwere in-
(BOP)
in Syrian hamsters. Animals were given BOP at a dose of 70 mg/kg body weight by subcutaneous injection and following a Z-week recovery period, were administered basal diet or basal diet containing 0.5, 0.75 and 1.5% ABA for 30 weeks. While the incidences of resultant pancreatic lesions, including hyperplasia, atypical hyperplasia and carcinoma, induced by BOP were not
Keywords: 3aminobenzamide; (2-0xopropyl)amine; pancreatic esis; poly(ADP-ribose)polymerase;
N-nitroso-biscarcinogenhamster
Introduction
vestigated
significantly mean were
influenced
numbers of significantly
dependent gested
by ABA
treatment,
those pancreatic decreased in
way.
The results the possible involvement
lesions
a
Pathology,
to: Yoichi Konishi, Department
Cancer
cho, Kashihara.
Center,
0304.3835/91/$03.50
Japan.
0
1991
Published and Printed in Ireland
of pan-
of Oncological
Nara Medical College.
Nara 634,
dose-
therefore sugof poly(ADP-
ribosyljation in the post-initiation phase creatic carcinogenesis in hamsters.
Correspondence
the
840
Shijo-
3-Aminobenzamide (ABA) is known to be a potent inhibitor of poly(ADP-ribose)polymerase [ 1 - 31, which has been demonstrated to catalyse the formation of poly(ADP-ribose) synthesized from nicotinamide adenine dinucleotide (NAD) [1,4,5]. This enzyme plays various roles in biological processes, including DNA repair [6,7], cell differentiation [8,9], cell proliferation [lO,ll], heat shock [ 121 and malignant transformation [ 13,141. have suggested possible Recently reports in involvement of poly(ADP-ribosyl)ation hepatocarcinogenesis. Thus carcinogenesis exof poly(ADPperiments using inhibitors ribose)polymerase during the initiation phase have indicated increased [15] or decreased 1161 induction of preneoplastic foci, depending on the model. In addition, the promotion effects of phenobarbital (PB) in rat liver can be blocked [ 171. In contrast, the inhibition of
El sevier Scientific Publishers Ireland Ltd
62
poly(ADP-ribose)polymerase was associated with enhancement of islet cell carcinoma induction by streptozotocin or alloxan in the rat pancreas [18,19]. Recently, in our laboratory, ABA reduced the level of initiation of pancreatic carcinogenesis by N-nitrosobis(Z-hydroxypropyl)amine (BHP) in Syrian hamsters [ZO]. N-Nitrosobis(2-oxopropyl)amine (BOP) is known to preferentially induce tumors of the pancreas in hamsters [21,22]. The present experiment was conducted to cast light on whether ABA might exert effects on the postinitiation phase of BOP-induced pancreatic carcinogenesis in hamsters. Materials Animals
and
and Methods
Group
4
2
Fig. 1. Experimental protocol for studying effects ABA on BOP induced pancreatic carcinogenesis hamsters.
of in
treatment
A total of 51 male Syrian golden hamsters (Shizuoka Laboratory Animal Center, Shizuoka, Japan), 6 weeks old, weighing approximately 80 - 100 g each, were housed 5 or 6 to an aluminum cage in an air-conditioned room maintained at 24OC and 60% humidity with a 12 h light/dark cycle. BOP, kindly supplied by Dr. Yukio Mori (Laboratory of Radiochemistry, Gifu Pharmaceutical University, Japan), was dissolved in sterilized saline immediately before application. ABA (Tokyo Kasei Kogyo Co., Ltd., Tokyo) was mixed into batches of commercial powdered diet Oriental M (Oriental Yeast Co., Ltd., Tokyo, Japan) at separate concentrations of 0.5 % , 0.75 % and 1.5%. Hamsters were divided into four groups according to the treatments shown in Fig. 1. Groups 1, 3 and 4 received a single subcutaneous injection of 70 mg BOP/kg body weight as the initiation step. Group 2 hamsters served as non-initiated controls receiving a subcutaneous injection of 0.9% NaCl. After a 2-week recovery period, group 1 received the basal diet for 30 weeks; group 2 the basal diet containing 0.75% ABA for 30 weeks; group 3 the basal diet containing 0.75% ABA for 9 weeks, followed by 0.5% ABA for 21 weeks; group 4 the basal diet containing 1.5% ABA for 9 weeks, followed by 0.75% ABA for 21 weeks. Body weights and food intake were
measured weekly. All surviving animals were sacrificed under ether anesthesia after 18 h fasting, 32 weeks after the commencement of the experiment. Histopathological
observations
The pancreas and the liver with gall bladder were removed and weighed. The pancreas tissue, divided into the gastric, splenic and duodenal lobes, and one slice from each lobe of the liver were taken and fixed in 95% ethanol containing 1% acetic acid for 2 h at 4OC. Paraffin enbedded sections were processed routinely and stained with hematoxylin and eosin. In the histopathologic determination, pancreas lesions were diagnosed according to the criteria documented in previous reports [22 - 241, and liver lesions in line with the Institute of Laboratory Animal Resources [25]. The quantitative data were statistically analyzed by x2 test and Student’s t-test methods for incidence and frequency, respectively. Results and Discussion Body and organ weights, and food and chemical intake data are shown in Table I. Reduction of body weights was observed with doses of 0.75 and 1.5% ABA after BOP initiation but not with 0.75% ABA alone, so dietary
17 10 9 15
1 2
90.0 90.4 90.2 88.5
5.48 3.57 + 5.12 zt 5.62
l
f
134.6 142.0 123.8 121.1
+ zt jz f
‘Significantly dSignificantly ‘Significantly ‘Significantly gSignificantly
different from group 1, P < different from group 2, P < different from group 2, P < different from group 2, P < different from group 2, P
61-
66
61
Elsevier Scientific Publishers Ireland Ltd.
Effects of 3-aminobenzamide on the post-initiation phase of Nnitrosobis(Zoxopropy1) amine induced pancreatic carcinogenesis in Syrian hamsters K. Mizumotob,
T. Tsujiuchia,
M. Tsutsumia,
A. Dendaa,
T. Amanumaa,
S. Kondoh”
and
Y. Konishi” ‘Department and
of Oncological
bDepartment
Pathology,
of Surgery
I, Kyushu
Cancer
Center,
Uniuersity.
Sara
Faculty
Medical
of Medicine,
College. 3-1-1,
840
Shijo-cho.
Maidashi,
Koshihara,
Higashi-ku,
Naro
Fukuoko
634
812
(Japan) (Received
25 April 1991)
(Revision
received
(Accepted
29 July
10 September
1991) 1991)
Summary Effects
of
3-aminobenzamide
pancreatic carcinogenesis nitrosobis(Z-oxopropyl)amine
after
(ABA) initiation
on
by Nwere in-
(BOP)
in Syrian hamsters. Animals were given BOP at a dose of 70 mg/kg body weight by subcutaneous injection and following a Z-week recovery period, were administered basal diet or basal diet containing 0.5, 0.75 and 1.5% ABA for 30 weeks. While the incidences of resultant pancreatic lesions, including hyperplasia, atypical hyperplasia and carcinoma, induced by BOP were not
Keywords: 3aminobenzamide; (2-0xopropyl)amine; pancreatic esis; poly(ADP-ribose)polymerase;
N-nitroso-biscarcinogenhamster
Introduction
vestigated
significantly mean were
influenced
numbers of significantly
dependent gested
by ABA
treatment,
those pancreatic decreased in
way.
The results the possible involvement
lesions
a
Pathology,
to: Yoichi Konishi, Department
Cancer
cho, Kashihara.
Center,
0304.3835/91/$03.50
Japan.
0
1991
Published and Printed in Ireland
of pan-
of Oncological
Nara Medical College.
Nara 634,
dose-
therefore sugof poly(ADP-
ribosyljation in the post-initiation phase creatic carcinogenesis in hamsters.
Correspondence
the
840
Shijo-
3-Aminobenzamide (ABA) is known to be a potent inhibitor of poly(ADP-ribose)polymerase [ 1 - 31, which has been demonstrated to catalyse the formation of poly(ADP-ribose) synthesized from nicotinamide adenine dinucleotide (NAD) [1,4,5]. This enzyme plays various roles in biological processes, including DNA repair [6,7], cell differentiation [8,9], cell proliferation [lO,ll], heat shock [ 121 and malignant transformation [ 13,141. have suggested possible Recently reports in involvement of poly(ADP-ribosyl)ation hepatocarcinogenesis. Thus carcinogenesis exof poly(ADPperiments using inhibitors ribose)polymerase during the initiation phase have indicated increased [15] or decreased 1161 induction of preneoplastic foci, depending on the model. In addition, the promotion effects of phenobarbital (PB) in rat liver can be blocked [ 171. In contrast, the inhibition of
El sevier Scientific Publishers Ireland Ltd
62
poly(ADP-ribose)polymerase was associated with enhancement of islet cell carcinoma induction by streptozotocin or alloxan in the rat pancreas [18,19]. Recently, in our laboratory, ABA reduced the level of initiation of pancreatic carcinogenesis by N-nitrosobis(Z-hydroxypropyl)amine (BHP) in Syrian hamsters [ZO]. N-Nitrosobis(2-oxopropyl)amine (BOP) is known to preferentially induce tumors of the pancreas in hamsters [21,22]. The present experiment was conducted to cast light on whether ABA might exert effects on the postinitiation phase of BOP-induced pancreatic carcinogenesis in hamsters. Materials Animals
and
and Methods
Group
4
2
Fig. 1. Experimental protocol for studying effects ABA on BOP induced pancreatic carcinogenesis hamsters.
of in
treatment
A total of 51 male Syrian golden hamsters (Shizuoka Laboratory Animal Center, Shizuoka, Japan), 6 weeks old, weighing approximately 80 - 100 g each, were housed 5 or 6 to an aluminum cage in an air-conditioned room maintained at 24OC and 60% humidity with a 12 h light/dark cycle. BOP, kindly supplied by Dr. Yukio Mori (Laboratory of Radiochemistry, Gifu Pharmaceutical University, Japan), was dissolved in sterilized saline immediately before application. ABA (Tokyo Kasei Kogyo Co., Ltd., Tokyo) was mixed into batches of commercial powdered diet Oriental M (Oriental Yeast Co., Ltd., Tokyo, Japan) at separate concentrations of 0.5 % , 0.75 % and 1.5%. Hamsters were divided into four groups according to the treatments shown in Fig. 1. Groups 1, 3 and 4 received a single subcutaneous injection of 70 mg BOP/kg body weight as the initiation step. Group 2 hamsters served as non-initiated controls receiving a subcutaneous injection of 0.9% NaCl. After a 2-week recovery period, group 1 received the basal diet for 30 weeks; group 2 the basal diet containing 0.75% ABA for 30 weeks; group 3 the basal diet containing 0.75% ABA for 9 weeks, followed by 0.5% ABA for 21 weeks; group 4 the basal diet containing 1.5% ABA for 9 weeks, followed by 0.75% ABA for 21 weeks. Body weights and food intake were
measured weekly. All surviving animals were sacrificed under ether anesthesia after 18 h fasting, 32 weeks after the commencement of the experiment. Histopathological
observations
The pancreas and the liver with gall bladder were removed and weighed. The pancreas tissue, divided into the gastric, splenic and duodenal lobes, and one slice from each lobe of the liver were taken and fixed in 95% ethanol containing 1% acetic acid for 2 h at 4OC. Paraffin enbedded sections were processed routinely and stained with hematoxylin and eosin. In the histopathologic determination, pancreas lesions were diagnosed according to the criteria documented in previous reports [22 - 241, and liver lesions in line with the Institute of Laboratory Animal Resources [25]. The quantitative data were statistically analyzed by x2 test and Student’s t-test methods for incidence and frequency, respectively. Results and Discussion Body and organ weights, and food and chemical intake data are shown in Table I. Reduction of body weights was observed with doses of 0.75 and 1.5% ABA after BOP initiation but not with 0.75% ABA alone, so dietary
17 10 9 15
1 2
90.0 90.4 90.2 88.5
5.48 3.57 + 5.12 zt 5.62
l
f
134.6 142.0 123.8 121.1
+ zt jz f
‘Significantly dSignificantly ‘Significantly ‘Significantly gSignificantly
different from group 1, P < different from group 2, P < different from group 2, P < different from group 2, P < different from group 2, P
