Animals ; Breast Diseases ; chemically induced ; Disease Models, Animal ; Female ; Mammary Neoplasms, Experimental ; chemically induced

In the present study, 13 clinical cases of canine mammary adenocarcinoma were evaluated in order to understand the effect of Tarantula cubensis extract (TCE) on tumor tissue. Punch biopsies were taken from the tumors before treatment with TCE. Subcutaneous injections of TCE were administered three times at weekly intervals (3 mL per dog). Between days 7 and 10 after the third injection, the tumor masses were extirpated by complete unilateral mastectomy. Pre- and post-treatment tumor tissues were immunohistochemically assessed. The expression of B-cell lymphoma 2 (Bcl-2) was found to be higher in pre-treatment compared to post-treatment tissues (p < 0.01) whereas Ki-67 expression was lower in post-treatment tissues (p < 0.01). No significant differences in fibroblast growth factor or vascular endothelial growth factor expression were observed between pre- and post-treatment tissues (p > 0.05). The apoptotic index was determined to be low before treatment and increased during treatment. These results suggest that TCE may be effective for controlling the local growth of canine mammary adenocarcinoma by regulating apoptosis.
Adenocarcinoma/*drug therapy/physiopathology ; Animals ; Apoptosis/drug effects ; Dog Diseases/*drug therapy/physiopathology ; Dogs ; Female ; Mammary Neoplasms, Animal/*drug therapy/physiopathology ; Mammary Neoplasms, Experimental/*drug therapy/physiopathology ; Mitosis/drug effects ; Spiders/*chemistry

BACKGROUNDBreast cancer has become one of the most common malignant tumors among females over the past several years. Breast carcinogenesis is a continuous process, which is featured by the normal epithelium progressing to premalignant lesions and then to invasive breast cancer (IBC). Targeting premalignant lesions is an effective strategy to prevent breast cancer. The establishment of animal models is critical to study the mechanisms of breast carcinogenesis, which will facilitate research on breast cancer prevention and drug behaviors. In this study, we established a feasible chemically-induced rat model of premalignant breast cancer.

METHODSFollowing the administration of the drugs (carcinogen, estrogen, and progestogen) to Sprague-Dawley (SD) rats, tumors or suspicious tumors were identified by palpation or ultrasound imaging, and were surgically excised for pathological evaluation. A series of four consecutive steps were carried out in order to determine the carcinogen: 7,12-dimethylbenzaanthracene (DMBA) or 1-methyl-1-nitrosourea, the route of carcinogen administration, the administration period of estrogen and progestogen, and the DMBA dosage.

RESULTSStable premalignant lesions can be induced in SD rats on administration of DMBA (15 mg/kg, administered three times) followed by administration of female hormones 5-day cycle.

RESULTSwere confirmed by ultrasound and palpation.

CONCLUSIONUnder the premise of drug dose and cycle, DMBA combined with estrogen and progestogen can be used as a SD rat model for breast premalignant lesions.

9,10-Dimethyl-1,2-benzanthracene ; Animals ; Breast Diseases ; chemically induced ; Disease Models, Animal ; Female ; Mammary Neoplasms, Experimental ; chemically induced ; Rats ; Rats, Sprague-Dawley

The inhibitory effect of selenium, vitamin E, and BHA on DMBA-induced mammary tumorigenesis in rats was investigated. Dietary vitamin E (200 IU/Kg diet) alone could not reduce the tumor incidence at 25 weeks after DMBA administration (10mg DMBA/rat) when selenium was deficient. Selenium supplementation (2ppm in drinking water) to rats fed a practical diet (0.17 ppm Se) reduced the tumor incidence to 14.3% from 75% at 27 weeks after DMBA administration. Dietary supplementation of BHA (0.75%) also reduced the incidence of DMBA-induced mammary tumor to 42.9% at 27 weeks after DMBA-treatment. Rats fed a diet deficient in both selenium and vitamin E contained significantly lower glutathione peroxidase activity and higher malondialdehyde in muscle. However, supplementation of selenium or BHA to the rats fed a practical diet did not alter the malondialdehyde content and glutathione peroxidase activities in muscle, skin and mammary gland. Dietary selenium increased the tissue selenium level. DMBA-induced mammary tumorigenesis was reduced by antioxidants tested but the anticarcinogenic effect of selenium or BHA seems to be independent of glutathione peroxi-dase activity.
9,10-Dimethyl-1,2-benzanthracene ; Animal ; Antioxidants/pharmacology* ; Butylated Hydroxyanisole/pharmacology ; Female ; Mammary Neoplasms, Experimental/pathology* ; Rats ; Selenium/pharmacology ; Vitamin E/pharmacology

The inhibitory effect of neutering on mammary gland tumor development in dogs has been well described. However, we observed that the effect of neutering on tumor malignancy may be altered by aging. Therefore, we characterized mammary tumors in aged dogs by analyzing the expression of cellular senescence markers. Expressions of p16, p38, p21, and p27 antibodies, which are senescence-associated markers, were assessed in canine mammary tumors of aged dogs via immunohistochemical analysis. In addition, correlations between those expressions were analyzed. Expression of p16 was negatively associated with strong nuclear p27 expression. Expression of p38 was observed in most of the mammary tumors examined, and negative p38 expression was related to positive p21 expression. Moreover, p21 expression was associated with p27 expression; negative p21 expression was associated with negative p27 expression, while positive p21 expression was associated with positive p27 expression. The results confirm that the p21- and p27-encoding genes have similar expression patterns in the mammary tumors of aged dogs. In the present study, we characterized the expression of cellular senescence markers in these tumors and elucidated the relationships among their expression patterns.
Aging ; Animals ; Antibodies ; Cell Aging ; Dogs* ; Mammary Glands, Human* ; Mammary Neoplasms, Animal

Increasing evidence suggests that cancer stem cells (CSCs) are responsible for tumor initiation and maintenance. Additionally, it is becoming apparent that cyclooxygenase (COX) signaling is associated with canine mammary tumor development. The goals of the present study were to investigate COX-2 expression patterns and their effect on CSC-mediated tumor initiation in primary canine mammary tissues and tumorsphere models using immunohistochemistry. Patterns of COX-2, CD44, octamer-binding transcription factor (Oct)-3/4, and epidermal growth factor receptor (EGFR) expression were examined in malignant mammary tumor (MMT) samples and analyzed in terms of clinicopathological characteristics. COX-2 and Oct-3/4 expression was higher in MMTs compared to other histological samples with heterogeneous patterns. In MMTs, COX-2 expression correlated with tumor malignancy features. Significant associations between COX-2, CD44, and EGFR were observed in low-differentiated MMTs. Comparative analysis showed that the levels of COX-2, CD44, and Oct-3/4 expression varied significantly among TSs of three histological grades. Enhanced COX-2 staining was consistently observed in TSs. Similar levels of staining intensity were found for CD44 and Oct-3/4, but EGFR expression was weak. Our findings indicate the potential role of COX-2 in CSC-mediated tumor initiation, and suggest that COX-2 inhibition may help treat canine mammary tumors by targeting CSCs.
Animals ; Antigens, CD44/genetics/metabolism ; Biomarkers, Tumor/genetics/metabolism ; Cell Transformation, Neoplastic/*genetics/metabolism ; Cyclooxygenase 2/*genetics/metabolism ; Dog Diseases/*genetics/metabolism ; Dogs ; Female ; Immunohistochemistry/veterinary ; Mammary Neoplasms, Animal/*genetics/metabolism ; Mammary Neoplasms, Experimental/*genetics/metabolism ; Neoplastic Stem Cells/*metabolism ; Octamer Transcription Factor-3/genetics/metabolism ; Receptor, Epidermal Growth Factor/genetics/metabolism ; Retrospective Studies

Animals ; Cell Line, Tumor ; Disease Models, Animal ; Female ; Humans ; Immunohistochemistry ; Male ; Mammary Neoplasms, Experimental ; chemistry ; pathology ; Mice ; Mitotic Index ; Neoplasm Transplantation ; Proto-Oncogene Proteins c-bcl-2 ; analysis ; Transplantation, Heterologous

OBJECTIVETo explore the effect of Yanghe Huayan Decoction (YHD, a representative recipe for warming yang mass dissipating) in inhibiting precancerosis of breast cancer (PBC) and on the protein and mRNA expression of ki67.

METHODSThe PBC rat model was established by dimethylbenzanthracene (DMBA), and 9 weeks later rats were randomly divided into the blank control group, the model group, the YHD group, the Sanjie Huatan Decoction group (SHD), the Pingxiao Tablet group (PT), and the tamoxifen group. Rats in the model group were administered with water by gastrogavage. Rats in the YHD group received YHD (deglued antler powder 12 g, prepared rhizome of rehmannia 9 g, cassia bark 6 g, white mustard seed 3 g, zedoary root 12 g, appendiculate cremastra pseudobulb 15 g, chekiang fritillary bulb 9 g, licorice root 6 g) at the daily dose of 7.2 g/kg by gastrogavage. Rats in the SHD group received SHD (oldenlandia diffusa 15 g, Scutellaria Barbata 15 g, Trichosanthes Kirilowii 15 g, pinellia 9 g) at the daily dose of 5.4 g/kg by gastrogavage. Rats in the PT group received PT at the daily dose of 144 mg/kg by gastrogavage. Those in the tamoxifen group received tamoxifen at the daily dose of 4 mg/kg by gastrogavage. Pathomorphological changes of the breast tissue were observed by HE staining. The positive rate and the gray value of ki67 expression were detected by immunohistochemical assay. And the expression of ki67 mRNA was detected by q-PCR.

RESULTSCompared with the model group, the general hyperplasia and the occurrence rate of precancerous lesion were higher and the occurrence rate of invasive carcinoma was lower in each treatment group (P < 0.05). Except the SHD group, the intensity of ki67 grey value increased in each treatment group (P < 0.05, P < 0.01). Except the PT group, the positive rate of ki67 and mRNA expression of ki67 increased in the rest treatment groups (P < 0.05, P < 0.01). Compared with the YHD group, there was no statistical difference in the occurrence rate of infiltration or the occurrence rate of precancerous lesion (P > 0.05). The positive rate of ki67 expression and mRNA expression of ki67 increased in the PT group, showing statistical difference (P < 0.05).

CONCLUSIONSYHD could partially inhibit and reverse canceration of breast cancer. It also could inhibit ki67 protein and mRNA expression. Its effect was similar to tamoxifen and superior to PT. So it was suitable for prevention and treatment of precancerous lesion of breast cancer.

Animals ; Disease Models, Animal ; Drugs, Chinese Herbal ; therapeutic use ; Female ; Ki-67 Antigen ; metabolism ; Mammary Neoplasms, Experimental ; chemically induced ; drug therapy ; metabolism ; Precancerous Conditions ; drug therapy ; metabolism ; Rats ; Rats, Sprague-Dawley

Interferon-γ (IFN-γ) has been used to control cancers in clinical treatment. However, an increasing number of reports have suggested that in some cases effectiveness declines after a long treatment period, the reason being unclear. We have reported previously that long-term IFN-γ treatment induces malignant transformation of healthy lactating bovine mammary epithelial cells (BMECs) in vitro. In this study, we investigated the mechanisms underlying the malignant proliferation of BMECs under IFN-γ treatment. The primary BMECs used in this study were stimulated by IFN-γ (10 ng/mL) for a long term to promote malignancy. We observed that IFN-γ could promote malignant cell proliferation, increase the expression of cyclin D1/cyclin-dependent kinase 4 (CDK4), decrease the expression of p21, and upregulate the expression of cellular-abelsongene (c-Abl) and histone deacetylase 2 (HDAC2). The HDAC2 inhibitor, valproate (VPA) and the c-Abl inhibitor, imatinib, lowered the expression level of cyclin D1/CDK4, and increased the expression level of p21, leading to an inhibitory effect on IFN-γ-induced malignant cell growth. When c-Abl was downregulated, the HDAC2 level was also decreased by promoted proteasome degradation. These data suggest that IFN-γ promotes the growth of malignant BMECs through the c-Abl/HDAC2 signaling pathway. Our findings suggest that long-term application of IFN-γ may be closely associated with the promotion of cell growth and even the carcinogenesis of breast cancer.
Animals ; Carcinogenesis/pathology* ; Cattle ; Cell Cycle Proteins/metabolism* ; Cell Proliferation/drug effects* ; Cell Transformation, Neoplastic/pathology* ; Cells, Cultured ; Epithelial Cells/pathology* ; Female ; Histone Deacetylase 2/metabolism* ; Imatinib Mesylate/pharmacology* ; Interferon-gamma/pharmacology* ; Mammary Glands, Animal/pathology* ; Mammary Neoplasms, Experimental/pathology* ; Proto-Oncogene Proteins c-abl/metabolism* ; Signal Transduction ; Valproic Acid/pharmacology*

OBJECTIVETo generate two genetically engineered mouse models of ErbB2/Neu positive-PTEN deficient breast cancer and to compare their biological properties.

METHODSThe genetically engineered mice previously developed with mouse mammary tumor virus (MMTV) promoter driven expression of activated ErbB2/Neu and recombinant Cre (FVB/N-MMTV-NIC) were interbred with Flox-PTEN mice; and FVB/N-ErbB2KI mice, harboring endogenous promoter driven activated ErbB2/Neu expression, FVB/N-MMTV-Cre mice and the flox-PTEN mice were interbred. Neu, Cre and PTEN genes were amplified by PCR for genotyping of the offsprings. ErbB2/Neu and PTEN expression in mammary tumors were detected by immunohistochemistry. Tumor formation time, tumor number, histopathology and lung metastasis were compared between two models, Ki-67 expression was detected by immunohistochemistry, and TUNEL staining of tumor tissues was performed.

RESULTSTwo genetically engineered mouse models of ErbB2/Neu positive-PTEN homozygous deficient breast cancer were generated. The models were confirmed by genotyping and immunohistochemistry. One model with exogenous MMTV promoter driven expression of activated ErbB2/Neu and Cre coupling PTEN disruption was designated as NIC/PTEN(-/-) mice, and the other with MMTV-Cre induced endogenous promoter driven expression of activated ErbB2/Neu with PTEN disruption was designated as ErbB2KI/PTEN(-/-) mice. The tumor formation time in NIC/PTEN(-/-) mice was significantly shorter than that of ErbB2KI/PTEN(-/-) mice (30 vs 368 d, P<0.01); the number of tumor and incidence of lung metastasis was also significantly higher in NIC/PTEN(-/-) mice (10 vs 1-2 and 75.0% vs 37.5%, respectively, Ps<0.01). The Two models displayed distinct histopathological morphology. NIC/PTEN(-/-) tumor showed more Ki-67 positive cells than ErbB2KI/PTEN(-/-) tumor did (86.9%±2.8% vs 37.4%±7.2%, P<0.01), while the amount of cell apoptosis in tumors was not significantly different between two models.

CONCLUSIONTwo genetically engineered mouse models of ErbB2/Neu positive-PTEN homozygous deficient breast cancer with different phenotypes have been successfully generated, which may provide useful resource for further investigation of the initiation and progression of HER2/ErbB2 breast cancer, as well as for the development of novel prevention and treatment regimens of this malignance.

Animals ; Breast Neoplasms ; genetics ; Disease Models, Animal ; Female ; Gene Deletion ; Mammary Neoplasms, Animal ; Mammary Tumor Virus, Mouse ; genetics ; Mice ; Mice, Transgenic ; PTEN Phosphohydrolase ; genetics ; Receptor, ErbB-2 ; genetics