共查询到20条相似文献，搜索用时 15 毫秒
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N. Kaneko M. Okuda N. Toyama T. Oikawa M. Watanabe N. Kanaya M. Yazawa K. Hasegawa M. Morimoto T. Hayashi S. Une M. Nakaichi Y. Taura H. Tsujimoto H. Inokuma 《Veterinary and comparative oncology》2005,3(4):203-210
In human and canine cancers, the inactivation of p53 protein as well as p53 gene mutation and MDM2 overexpression result in centrosome amplification that in turn contributes to chromosomal instability. To explore the usefulness of the detection of centrosome amplification as a surrogate marker of dysfunction in the p53 pathway, we systematically analysed centrosome amplification, p53 overexpression, p53 gene mutation and MDM2 overexpression in canine tumours. Centrosome amplification was detected in 16 of 51 (31%) naturally developing tumours in dogs. All the tumour specimens with aberrations in the p53 pathway, including p53 overexpression, p53 gene mutation or MDM2 overexpression, showed centrosome amplification, suggesting that the detection of centrosome amplification could serve as a preliminary surrogate marker of dysfunction in the p53 pathway. 相似文献
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The purpose of the study was to evaluate clonality and presence of numerical chromosomal and centrosomal aberrations in 5 established feline fibrosarcoma cell lines and in a fetal dermal fibroblast cell line as a control. The clonality of all cell lines was examined using limited-dilution cloning. The number of chromosomes was counted in metaphase spreads. The immunocytochemical analysis of centrosome numbers was performed by indirect immunofluorescence using a monoclonal antibody that targets γ-tubulin, a well-characterized component of centrosomes. Monoclonal cell populations could be established from all cell lines. In all feline fibrosarcoma cell lines, the number of chromosomes deviated abnormally from the normal feline chromosome number of 2n = 38, ranging from 19 to 155 chromosomes per cell. Centrosome hyperamplification was observed in all 5 feline fibrosarcoma cell lines with a proportion of cells (5.7 to 15.2%) having more than 2 centrosomes. In the control cell line, only 0.6% of the cells had more than 2 centrosomes. In conclusion, the examinations revealed that centrosome hyperamplification occurs in feline fibrosarcoma cell lines. The feline fibrosarcoma cell lines possessed 10 to 25 times as many cells with centrosome hyperamplification as the control cell line. These observations suggest an association of numerical centrosome aberrations with karyotype instability by increasing the frequency of chromosome missegregation. The results of this study may be helpful for further characterization of feline fibrosarcomas and may contribute to the knowledge of cytogenetic factors that may be important for the pathogenesis of feline fibrosarcomas. 相似文献
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OBJECTIVE: To investigate activation of the mammalian target of rapamycin (mTOR) pathway and the antitumor effect of rapamycin in canine osteosarcoma cells. SAMPLE POPULATION: 3 established primary canine osteosarcoma cell lines generated from naturally developing tumors. PROCEDURES: Expression of total and phosphorylated mTOR and p70S6 kinase was assessed by use of western blot analysis in canine osteosarcoma cells with and without the addition of rapamycin. A clonogenic assay was performed to determine the surviving fraction of osteosarcoma cells at various concentrations of rapamycin. RESULTS: Total and phosphorylated mTOR and p70S6 kinase expression was evident in all 3 cell lines evaluated, which was indicative of activation of this pathway. Treatment with rapamycin resulted in a time-dependent decrease in phosphorylated mTOR expression and a lack of detectable phosphorylated p70S6 kinase. No detectable change in expression of total mTOR and total p70S6 kinase was identified after rapamycin treatment. The clonogenic assay revealed a significant dose-dependent decrease in the surviving fraction for all 3 cell lines when treated with rapamycin. CONCLUSIONS AND CLINICAL RELEVANCE: These data indicated that mTOR and its downstream product are present and active in canine osteosarcoma cells. The pathway can be inhibited by rapamycin, and treatment of cells with rapamycin decreased the surviving tumor cell fraction. These data support the molecular basis for further investigation into the use of mTOR inhibitors as an antineoplastic approach for dogs with osteosarcoma. 相似文献
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N. Kanaya M. Yazawa M. Mochizuki R. Nishimura N. Sasaki A. Setoguchi K. Ohno H. Tsujimoto 《Veterinary and comparative oncology》2005,3(1):45-46
Introduction: It has been reported that 40–50% of canine osteosarcoma cases have p53 mutations. The p53 tumor supressor gene plays a central role in cell cycle regulation and induction of apoptosis. We previously showed that adenoviral vector expressing canine P53 (AxCA‐cp53) inhibited growth of cultured canine osteosarcoma cell lines. Here, we evaluated anti‐tumor effect of adenovirus‐mediated p53 gene therapy on the growth of canine osteosarcomas transplanted into nude mice.
Methods: Nine nude mice were subcutaneously injected with cells of a canine osteosarcoma cell line (POS) having p53 gene mutation. The transplanted tumors formed into nude mice were injected with AxCA‐cp53, AxCA‐LacZ (adenovirus vector expressing LacZ) or PBS (3 mice each) 7 times during 15 days. Tumor sizes were measured every 3 days for 27 days after injection with the adenovirus vectors. Expression efficiency of the adenovirus‐mediated gene transfer was examined by X‐gal staining and P53 immunostaining. Effects of the P53 expression on cell cycle control were examined by RT‐PCR for expression of p21 gene downstream of P53.
Results: Significant differences in the tumor size was observed between the transplanted osteosarcoma tissues injected with AxCA‐cp53 and those injected with AxCA‐LacZ or PBS. Expressions of LacZ and P53 were confirmed at the injection sites of the tumors. Moreover, p21 mRNA expression was shown to be induced in the AxCA‐cp53‐injected tumors, indicating the funciton of P53 to induce cell cycle arrest.
Conclusions: Adenoviral vector expressing canine P53 inhibited the growth of canine ostersarcoma transplanted into nude mice. 相似文献
Methods: Nine nude mice were subcutaneously injected with cells of a canine osteosarcoma cell line (POS) having p53 gene mutation. The transplanted tumors formed into nude mice were injected with AxCA‐cp53, AxCA‐LacZ (adenovirus vector expressing LacZ) or PBS (3 mice each) 7 times during 15 days. Tumor sizes were measured every 3 days for 27 days after injection with the adenovirus vectors. Expression efficiency of the adenovirus‐mediated gene transfer was examined by X‐gal staining and P53 immunostaining. Effects of the P53 expression on cell cycle control were examined by RT‐PCR for expression of p21 gene downstream of P53.
Results: Significant differences in the tumor size was observed between the transplanted osteosarcoma tissues injected with AxCA‐cp53 and those injected with AxCA‐LacZ or PBS. Expressions of LacZ and P53 were confirmed at the injection sites of the tumors. Moreover, p21 mRNA expression was shown to be induced in the AxCA‐cp53‐injected tumors, indicating the funciton of P53 to induce cell cycle arrest.
Conclusions: Adenoviral vector expressing canine P53 inhibited the growth of canine ostersarcoma transplanted into nude mice. 相似文献
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Introduction: Aberrant expression of the proto‐oncogene c‐Met has been noted in a variety of human cancers. In dogs, inappropriate Met expression has been identified in canine osteosarcoma (OSA) tumor samples. To better define the potential role of Met dysregulation in canine cancer, we cloned canine Met, HGF, and HGF activator and evaluated their expression patterns in a variety of canine tumor cell lines.
Methods: Canine Met, HGF, and HGF activator were cloned from normal canine liver and canine OSA cell lines using primers based on regions of homology between mouse and human sequences as well as 5' and 3' RACE.
Results: Inappropriate expression of Met was found in canine cell lines derived from OSAs, mast cell tumors, histiocytic sarcomas, hemangiosarcoma, and melanomas. Both HGF and HGF activator were found to be expressed in several of these tumor cell lines, providing evidence of a possible autocrine loop of Met stimulation. Incubation of canine tumor cell lines with rhHGF resulted in Met autophosphorylation and activation of the downstream signaling elements Gab1, Akt and Erk1/2. Scattering of tumor cells in response to HGF occurred under conditions of cell stress, such as serum starvation. Lastly, the Met inhibitor PHA‐665752 blocked HGF induced phosphorylation of canine Met and Gab1.
Conclusions: These studies provide evidence that similar to the case in human tumors, aberrant Met expression may play an important role in the biology of canine cancer. As such, inhibition of Met function may represent a potentially useful novel therapeutic approach. 相似文献
Methods: Canine Met, HGF, and HGF activator were cloned from normal canine liver and canine OSA cell lines using primers based on regions of homology between mouse and human sequences as well as 5' and 3' RACE.
Results: Inappropriate expression of Met was found in canine cell lines derived from OSAs, mast cell tumors, histiocytic sarcomas, hemangiosarcoma, and melanomas. Both HGF and HGF activator were found to be expressed in several of these tumor cell lines, providing evidence of a possible autocrine loop of Met stimulation. Incubation of canine tumor cell lines with rhHGF resulted in Met autophosphorylation and activation of the downstream signaling elements Gab1, Akt and Erk1/2. Scattering of tumor cells in response to HGF occurred under conditions of cell stress, such as serum starvation. Lastly, the Met inhibitor PHA‐665752 blocked HGF induced phosphorylation of canine Met and Gab1.
Conclusions: These studies provide evidence that similar to the case in human tumors, aberrant Met expression may play an important role in the biology of canine cancer. As such, inhibition of Met function may represent a potentially useful novel therapeutic approach. 相似文献
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Enrofloxacin enhances the effects of chemotherapy in canine osteosarcoma cells with mutant and wild‐type p53 
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下载免费PDF全文 D. York S. S. Withers K. D. Watson K. W. Seo R. B. Rebhun 《Veterinary and comparative oncology》2017,15(3):1087-1100
Adjuvant chemotherapy improves survival time in dogs receiving adequate local control for appendicular osteosarcoma, but most dogs ultimately succumb to metastatic disease. The fluoroquinolone antibiotic enrofloxacin has been shown to inhibit survival and proliferation of canine osteosarcoma cells in vitro. Others have reported that fluoroquinolones may modulate cellular responses to DNA damaging agents and that these effects may be differentially mediated by p53 activity. We therefore determined p53 status and activity in three canine osteosarcoma cell lines and examined the effects of enrofloxacin when used alone or in combination with doxorubicin or carboplatin chemotherapy. Moresco and Abrams canine osteosarcoma cell lines contained mutations in p53, while no mutations were identified in the D17 cells or in a normal canine osteoblast cell line. The addition of enrofloxacin to either doxorubicin or carboplatin resulted in further reductions in osteosarcoma cell viability; this effect was apparent regardless of p53 mutational status or downstream activity. 相似文献
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Eighty-three canine cutaneous mast cell tumors were graded histologically and evaluated immunohistochemically for p53 tumor-suppressor protein expression. An avidin-biotin immunohistochemical protocol incorporated a rabbit polyclonal antibody (CM-1) directed against normal and mutant p53 protein. Positive staining was observed in 44.6% (37/83) of tumors and included 50% (12/24) of grade I (well differentiated) tumors, 46.9% (23/49) of grade II (intermediate differentiation) tumors, and 20% (2/10) of grade III (poorly differentiated) tumors. A statistically significantly higher proportion (P < 0.019) of tumors from the head and neck (83.3%, 10/12), stained positive for p53 than tumors from the thorax, back, abdomen, and axilla (39.4%, 13/33), legs (35.7%, 10/28), or prepuce, scrotal, or inguinal areas (44.4%, 4/9). No statistically significant difference between p53 labeling and histologic grade, breed, or tumor size was present. Survival data were available for 53/83 (63.9%) of dogs. Positive reactivity for p53 was observed in 47% (25/53) of tumors within this group, with 57.9% (11/19) of grade I, 43.3% (13/30) of grade II, and 25% (1/4) of grade III tumors labeled. Mean survival time for the 53 dogs was 12.1 months. The median survival time for dogs with grade III tumors or tumors >5 cm was statistically significantly shorter (P < 0.0001) than for dogs with grades I and II or smaller tumors. Although p53 protein abnormalities may play a role in tumor development or behavior in some canine cutaneous mast cell tumors, immunoreactivity was not associated with lack of tumor differentiation, tumor locations previously shown to demonstrate aggressive biological behavior, breed predisposition, or survival times. 相似文献
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Miyajima N Watanabe M Ohashi E Mochizuki M Nishimura R Ogawa H Sugano S Sasaki N 《Journal of veterinary internal medicine / American College of Veterinary Internal Medicine》2006,20(2):348-354
Retinoids show antitumor effects on human acute promyelocytic leukemia and other tumors via retinoid receptors. In dogs, the role of retinoid receptors in inhibiting tumor development remains unclear. To evaluate the correlation between the degree of expression of retinoic acid receptor alpha (RARalpha) mRNA and the antiproliferative effects of all-trans retinoic acid (ATRA) treatments, expression analysis of RARalpha mRNA and cell growth inhibition assay were performed on 17 established canine tumor cell lines, including 6 mammary gland tumor (MGT) cell lines, 3 osteosarcoma cell lines, 5 melanoma cell lines, and 3 mast cell tumor (MCT) cell lines. Among the cell lines investigated, all 3 MCT cell lines showed high expression of RARalpha, and the most effective cell growth inhibition was observed in ATRA-treated MCT cell lines. However, remarkable antiproliferative effects of ATRA treatments were not observed on other tumor cell lines with moderate or low RARalpha mRNA expression. As a result of the relationship between RARalpha mRNA expression and ATRA treatment with regression analysis, statistically significant correlation was suggested. Furthermore, real-time quantitative polymerase chain reaction analysis of RARalpha was performed on MCT tissue samples of dogs with spontaneous disease, and 5 of 9 tissues showed high expression. These results suggest that ATRA may be an effective antitumor agent for MCT in dogs, and that prior measurement of expression of RARalpha mRNA may be a good indicator of the effectiveness of ATRA treatment. 相似文献
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Hosoya K Murahari S Laio A London CA Couto CG Kisseberth WC 《American journal of veterinary research》2008,69(4):519-526
OBJECTIVE: To evaluate the biological activity of dihydroartemisinin on canine osteosarcoma cell lines in vitro. SAMPLE POPULATION: 4 canine osteosarcoma cell lines. PROCEDURES: Cell viability assays were performed on canine osteosarcoma cell lines OSCA2, OSCA16, OSCA50, and D17 after 24, 48, and 72 hours of treatment with dihydroartemisinin at concentrations of 0.1 to 100 microM. Apoptosis was assessed by use of an ELISA for free nuclosomal DNA fragmentation and by western blot analysis for cleavage of caspase 3. Cell cycle analysis was performed by use of staining with propidium iodide and flow cytometry. Detection of reactive oxygen species (ROS) was conducted in the D17 cell line by use of 6-carboxy-2',7'-dihydrofluorescein diacetate and flow cytometry. RESULTS: The concentration of dihydroartemisinin required for 50% inhibition of cell viability (IC50) was achieved in all 4 canine osteosarcoma cell lines and ranged from 8.7 to 43.6 microM. Induction of apoptosis was evident as an increase in nucleosomal DNA fragmentation, cleavage of caspase 3, and an increase in the population in the sub G0/G1 phase of the cell cycle detected by flow cytometry. Exposure to dihydroartemisinin also resulted in a decrease in the G0/G1 population. Iron-dependent generation of ROS was detected in dihydroartemisinin-treated D17 cells; ROS generation increased in a dose-dependent manner. CONCLUSIONS AND CLINICAL RELEVANCE: Incubation with dihydroartemisinin resulted in biological activity against canine osteosarcoma cell lines, which included induction of apoptosis and arrest of the cell cycle. Clinical trials of dihydroartemisinin in dogs with osteosarcoma should be conducted. 相似文献
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Canine osteosarcoma (OS) cell lines contain mutations that directly or indirectly inactivate the tumor suppressor genes p53 and retinoblastoma. Another important tumor suppressor, PTEN, is mutated in many human cancers. To determine whether inactivation of PTEN plays a role in the pathogenesis of canine OS, we studied its expression in canine OS cell lines and tumors. Four of five canine OS cell lines (CO2, C03, CO5, and CO7) constitutively express high levels of the phosphorylated form of Akt, an indirect indicator of aberrant PTEN expression. PTEN protein is essentially absent from three of these cell lines (CO2, CO5, and CO7), whereas C03 contains a potentially inactivating amino acid substitution in PTEN at codon 340. Genomic hybridization experiments indicate that CO2, CO5, and CO7 contain large deletions within the PTEN gene. Ten of 15 OS tumors exhibit variable or negative PTEN staining. Evaluation of a PTEN-negative staining tumor by Southern blotting indicates that the PTEN gene is deleted in this tumor. These results indicate that PTEN is mutated or downregulated in a high percentage of canine OS cell lines and tumors and likely plays an important role in the pathogenesis of the disease. 相似文献
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Masaya IGASE Chung Chew HWANG Matt COFFEY Masaru OKUDA Shunsuke NOGUCHI Takuya MIZUNO 《The Journal of veterinary medical science / the Japanese Society of Veterinary Science》2015,77(5):541-548
Oncolytic virotherapy is a new strategy for cancer treatment for humans and
dogs. Reovirus has been proven to be a potent oncolytic virus in human medicine. Our
laboratory has previously reported that canine mast cell tumor and canine lymphoma were
susceptible to reovirus. In this study, canine solid tumor cell lines (mammary gland
tumor, osteosarcoma and malignant melanoma) were tested to determine their susceptibility
towards reovirus. We demonstrated that reovirus induces more than 50% cell death in three
canine mammary gland tumors and one canine malignant melanoma cell line. The
reovirus-induced cell death occurred via the activation of caspase 3. Ras activation has
been shown to be one of the important mechanisms of reovirus-susceptibility in human
cancers. However, Ras activation was not related to the reovirus-susceptibility in canine
solid tumor cell lines, which was similar to reports in canine mast cell tumor and canine
lymphoma. The results of this study highly suggest that canine mammary gland tumor and
canine malignant melanoma are also potential candidates for reovirus therapy in veterinary
oncology. 相似文献
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Jaffe MH Hosgood G Taylor HW Kerwin SC Hedlund CS Lopez MK Davidson JR Miller DM Paranjpe M 《Veterinary pathology》2000,37(1):40-46
One hundred twenty-six cutaneous mast cell tumors obtained by excisional biopsy from 106 dogs were evaluated using immunohistochemical staining for the presence of p53 protein. A standard avidin-biotin immunohistochemical protocol was used incorporating a polyclonal antibody of rabbit origin (CM-1) as the primary antibody. Histopathologic grading of tumors was performed on hemotoxylin and eosin-stained samples. There was a significant difference in the percentage of cells staining positive for p53 for the histopathologic grades (P = 0.0005). Grade III tumors had a significantly greater p53 content than did grade I or II tumors (P < 0.05). Clinical data obtained retrospectively was available for 54 dogs. Tumor recurred in 19 of 54 (35.2%) dogs. Twenty-nine dogs died by the end of the study; 9 of 29 (31.0%) died of mast cell tumor disease. Histopathologic grade showed a significant negative association with survival time. Both clinical stage and histopathologic grade showed a significant negative association with time to recurrence. The percentage of cells staining positive for p53 did not significantly improve the forward analysis. Immunohistochemical detection of p53 did not appear useful in characterizing the clinical association between cutaneous mast cell tumor cellular features and survival time or time to tumor recurrence in dogs. 相似文献
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Expression and significance of p53, rb,p21/waf-1, p16/ink-4a,and PTEN tumor suppressors in canine melanoma 总被引：3，自引：0，他引：3
The role of tumor suppressor genes in the pathogenesis of canine melanoma is incompletely understood. The genes encoding the tumor suppressors p53, Rb, p21 (waf-1), p16 (ink-4a), and PTEN have been postulated to contribute to the pathogenesis of melanoma in humans and experimental animal models. To assess whether inactivation of these genes similarly contributes to the origin and progression of canine melanoma, we examined their expression in seven distinct canine melanoma cell lines and in 31 retrospective samples (representing 29 dogs) of spontaneous canine melanoma. Various patterns suggestive of loss of tumor suppressor function emerged in these cell lines. The most frequently observed abnormality was loss or significant reduction of p16 expression in six of seven cell lines and in 21 of 26 tumor samples. Loss or significant reduction of PTEN expression was seen in four of seven cell lines and in 13 of 27 tumor samples. Although p53 was detectable in all the cell lines and in 24 of 30 tumors, exclusion of p53 from the nuclear compartment was observed in each of the cell lines and in 18 of 25 tumor samples. These results indicate that loss of function of these tumor suppressor proteins is a common occurrence that may contribute to the origin of canine melanoma. In our sample population, abnormalities in the expression or localization of one or more tumor suppressor proteins occurred with similar frequency in malignant and benign tumors; thus, additional work is necessary to determine how these proteins may impact disease progression and response to therapy. 相似文献