• Environmental Mutagens and Carcinogens
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• v.21 no.1
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• pp.44-50
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• 2001

To identify nongenotoxic carcinogen determined as negative by ICH guideline-recommended standard genotoxicity test battery; Ames test, chromosome aberration assay, mouse lymphoma $tk^{+/-}$ assay, in vivo micronucleus assay, we picked bisphenol A as a model compound. In this study, we applied in vitro BalB/c 3T3 cell transformation assay and Syrian hamster embryo (SHE) cell transfarmation assay. Bisphenol A was treated upto $769.2 ug/m{\ell}$ in BalB/c 3T3 cells and upto $125 ug/m{\ell}$ in SHE cells. bisphenol A didn't induced morphological transformation both with one stage treatment protocol and with two stage treatment protocol. But, treated far 48 hr, Bisphenol A induced morphological transformation significantly in SHE cells.

• Asian Pacific Journal of Cancer Prevention
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• v.13 no.11
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• pp.5753-5757
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• 2012

Apoptosis, also known as cell suicide or programmed cell death, removes unwanted and genetically damaged cells from the body. Evasion of apoptosis is one of the major characteristic features of rapidly proliferating tumor cells. Chemopreventive agents inhibit or suppress tumor formation through apoptotic induction in target tissues. The aim of the present study was to investigate the pro-apoptotic potential of lupeol during 7,12-dimethylbenz(a) anthracene (DMBA) induced hamster buccal pouch carcinogenesis. Topical application of 0.5% DMBA three times a week for 14 weeks in the buccal pouches of golden Syrian hamsters resulted in oral squamous cell carcinoma. The expression pattern of apoptotic markers was analyzed using immunohistochemistry (p53, Bcl-2, Bax) and ELISA reader (caspase 3 and 9). In the present study, 100% tumor formation with defects in apoptotic markerexpression pattern was noticed in hamsters treated with DMBA alone. Oral administration of lupeol at a dose of 50mg/kg bw completely prevented the formation oral tumors as well as decreased the expression p53 and Bcl-2, while increasing the expression of Bax and the activities of caspase 3 and 9. The present study thus indicated that lupeol might inhibit DMBA-induced oral tumor formation through its pro-apoptotic potential in golden Syrian hamsters.

• Toxicological Research
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• v.17 no.3
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• pp.167-171
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• 2001

Oral mucous membrane test using Syrian hamsters was performed to evaluate the reliability as a model system for the assessment of the potentially irritating substances intended for the mucous membranes, and to determine the irritating potential of a new emulsion-type formulated toothpaste. After test substances were implanted into the cheek pouches of hamsters with diluents (20 mg/kg) under pento-barbital sodium anesthesia, we made the comparison in irritation between emulsion-type and dispersion-type of triclosan (TCS) formulations in the range of 0.2% to 0.3%. The emulsion-type formulations using non-ionic surfactant showed less mucosal lesion than other commercial toothpastes with 0.3% TCS, or dispersion-type ones. However, no significant difference in irritation was detected between 0.2% and 0.3% TCS. We report that this hamster cheek pouch method could be a reliable approach for the evaluation slight difference in the irritating potentials of cosmetics and hygiene products intended for the lips or other mucous membranes, and this method showed that the new emulsion-type formulation significantly lowered the TCS-induced toxicity, compared with other commercial toothpastes.

• Korean Journal of Veterinary Pathology
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• v.6 no.1
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• pp.41-48
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• 2002

Oval cell is considered as facultative precursor cells for both hepatocytes and biliary cells, as well as origin of hepatocellar and cholangiocellular carcinoma (CCC) during carcinogenesis or toxic liver injury. To clarify the cellular origin or differentiation of cholagiocarcinogensis, the fate of carcinogen-induced oval cells was pathologically and phenotypically chased in Syrian golden hamster liver after Clonorchis sinensis (CS) infection which would give rise to a promoting effect. Two week treatment of hamsters with 0.005% diethylnitrosamine (DEN) followed by 2 week treatment of 1% 2-acetylaminofluorene (AAF) under choline deficient diet resulted in massive proliferation of BrdU labeleed and PCNA positive oval cells showing various distinct morphology, histochemical and immunohistochemical phenotypes for GGT, cytokeratin 19 and OV-6. Oval cells also frequently form ductular-like structures or phenotypically show hepatocyte-like characteristics. After CS infection, the oval cells showed sequential morphological changes to atypicl proliferating bile ductules and all hamsters thereafter developed well differentiated and anaplastic CCC at 16 week after CS infection. In electron microscopy, some bile ductules were constructed by intermediate oval cells and bile ductular cells surrounded by basement membrane. The results of this study strongly suggest that CCC developed in the present study were originated from hepatic stem-like oval cells, supporting the theory of stem cell origin of cancers. In addition, this hamster model would be valuable for the molecular mechanistic study during chemical-triggered cholangiocarcinogenesis.

• Parasites, Hosts and Diseases
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• v.51 no.6
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• pp.711-717
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• 2013

Opisthorchis viverrini (O. viverrini) is a well-known causative agent of cholangiocarcinoma (CCA) in humans. CCA is very resistant to chemotherapy and is frequently fatal. To understand the pathogenesis of CCA in humans, a rodent model was developed. However, the development of CCA in rodents is time-consuming and the xenograft-transplantation model of human CCA in immunodeficient mice is costly. Therefore, the establishment of an in vivo screening model for O. viverrini-associated CCA treatment was of interest. We developed a hamster CCA cell line, Ham-1, derived from the CCA tissue of O. viverrini-infected and N-nitrosodimethylamine-treated Syrian golden hamsters. Ham-1 has been maintained in Dulbecco's Modified Essential Medium supplemented with 10% fetal bovine serum for more than 30 subcultures. These cells are mostly diploid (2n=44) with some being polyploid. Tumorigenic properties of Ham-1 were demonstrated by allograft transplantation in hamsters. The transplanted tissues were highly proliferative and exhibited a glandular-like structure retaining a bile duct marker, cytokeratin 19. The usefulness of this for in vivo model was demonstrated by berberine treatment, a traditional medicine that is active against various cancers. Growth inhibitory effects of berberine, mainly by an induction of G1 cell cycle arrest, were observed in vitro and in vivo. In summary, we developed the allo-transplantable hamster CCA cell line, which can be used for chemotherapeutic drug testing in vitro and in vivo.

• Asian Pacific Journal of Cancer Prevention
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• v.16 no.15
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• pp.6279-6284
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• 2015

Opisthorchis viverrini (OV)-induced cholangiocarcinoma (CCA) is an important cancer in the Great Mekong region, particularly in Thailand. Limitations of treatment options and the lack of an effective diagnostic tool for early detection of CCA are major concerns for the control of this type of cancer. The aim of the study was to investigate anti-CCA activity of the ethanolic extract of Atractylodes lancea (Thunb.) DC., and the applicability of positron emission tomography-computed tomography (PET-CT) as a tool for detection and monitoring the progression of CCA in Opisthorchis viverrini (OV)/dimethylnitrosamine (DMN)-induced CCA hamsters. Male Syrian hamsters were used for toxicity tests and anti-CCA activity evaluation. Development of CCA was induced by initial feeding of 50 metacercariae of OV, followed by drinking water containing 12.5 ppm of DMN in hamsters. The ethanolic extract of A. lancea (Thunb.) DC. was administered orally for 30 days. PET-CT was performed every 4 weeks after initiation of CCA using 18F-fluorodeoxyglucose ($^{18}F-FDG$). Results from the present study suggest that the ethanolic extract of A. lancea (Thunb.) DC. rhizome exhibited promising anti-CCA activity and safety profile in the OV/DMN-induced hamster model. To successfully apply PET-CT as a tool for early detection of tumor development and progression, modification of radiolabeling approach is required to improve its specificity for CCA cells.

• Asian Pacific Journal of Cancer Prevention
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• v.17 no.7
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• pp.3527-3531
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• 2016

Recombinant human bone morphogenetic protein-2 (rhBMP-2 ), a member of the TGF-${\beta}$ family, has been used widely in recent years to regenerate defects of the maxillary and mandible bones. Such defects are sometimes caused by resection of oral squamous cell carcinoma (OSCC) yet the biologic effects of rhBMP-2 on these carcinomas are not fully clear. The objective of this study was to determine histologically whether rhBMP-2 produces adverse effects on angiogenesis during induction of OSCC, a biologic process critical for tumor formation in an experimental model in the buccal pouch of golden Syrian hamsters. Buccal cavities were exposed to painting with 0.5% DMBA in liquid paraffin three times a week for 14 weeks, then biopsies were taken. Division was into 2 groups: a study group of 10 hamsters receiving $0.25{\mu}g/ml$ of rhBMP-2 in the $3^{rd}$ and $6^{th}$ weeks; and a control group of 10 hamsters which did not receive any additional treatment. VEGF expression and microvessel density were measured but no differences were noted between the two groups. According to this study, rh-BMP-2 does not stimulate angiogenesis during induction of OCSSs.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.31 no.3
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• pp.219-227
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• 2005

Purpose: Abnormalities in the p53 gene are regarded as the most consistent genetic abnormalities detected in head and neck squamous cell carcinogenesis. Two new members of the p53 gene family, p73 and p63 have recently been identified. They share considerable sequence homology with p53 in the transactivation, DNA binding, and oligomerization domains, indicating possible involvement in carcinogenesis. Disruption of the homeostatic balance between proliferation and apoptosis is widely believed to contribute to human oral carcinogenesis. The aim of this study was to analyze expression of p63 in squamous cell carcinogenesis and to compare with immunochemical markers representing cell proliferation and apoptosis. Materials and Methods: Using the Syrian hamster oral cancer model, the fraction of apoptotic (apoptotic index-AI), proliferating (mitotic index-MI) and p63 expressing keratinocytes were examined at normal, dysplastic and malignant oral epithelium using the TUNEL assay, PCNA and p63 immunostaining. Results: p63 significantly increased between normal and dysplastic epithelium and between dysplastic and malignant epithelium. PCNA significantly increased between normal and dysplastic epithelium and between normal and malignant epithelium. However, increase between dysplastic and malignant epithelium, though still increasing, was not statistically significant. The percentage of TUNEL positive cells increased from normal to dysplastic epithelium and returned to normal keratinocyte level in the malignant epithelium. However, differences between tissue types were not significant. The ratio of MI:AI increased significantly only in the dysplastic-malignant epithelial transition. The increase of p63 expression closely reflected the change in the MI:AI ratio during oral carcinogenesis. Conclusion: The p63 may be associated with the regulation of epithelial proliferation and apoptosis in DMBA-induced hamster buccal pouch squamous cell carcinogenesis. Further study is required to investigate which p63 isoforms are involved in hamster buccal pouch carcinogenesis.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.30 no.5
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• pp.400-405
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• 2004

Angiogenesis inhibition is major concern to cancer chemotherapy and many studies about compound inhibiting angiogenesis is in progression. The long-known preventive effect of plant-based diet on tumorigenesis and other chronic diseases is well documented. Especially soy extract, genistein, is known to be potent angiogenesis inhibitor and prevent development and progression of tumor. In the present study, the effect of angiogenesis on tumorigenesis and chemopreventive effect of genistein by angiogenesis inhibition in hamster buccal pouch oral carcinigenesis model induced by 7.12-dimethylbenza(a)nthracene (DMBA) was studied. Forty eight Syrian Golden young adult hamsters (150-200 gm) were divided into two groups. In control group, 0.5% DMBA in heavy mineral oil was applied to hamster buccal pouch three times a week and in experimental group, 0.1 mg of genistein is administered orally everyday in addition to DMBA application. The animals were euthanized from 2 weeks to 16 weeks with interval of 2 week. H&E staining and immunohistochemistry was performed to evaluate microvessel density by using factor VIII-related antigen and avidin-biotin technique. Microvessels per area was quantified and compared between control and experimental group statistically. The results were as follows. 1. Microvessel density was increased time dependently in both groups and especially the increase was significant from 12 weeks to 16 weeks. 2. When comparing both group, the experimental group showed significantly low microvessel density than control group in 12 weeks (p=0.043), 14 weeks (p=0.050), 16 weeks (p=0.037). Based on these results, it was concluded that genistein influenced oral carcinogenesis by angiogenesis inhibition.