Background Overexpression of breast cancer-specific gene 1 （SNCG） is associated with poor prognosis in advanced breast cancer patients. This study aimed to determine the effects of SNCG knockdown in breast cancer ce...Background Overexpression of breast cancer-specific gene 1 （SNCG） is associated with poor prognosis in advanced breast cancer patients. This study aimed to determine the effects of SNCG knockdown in breast cancer cells by using small hairpin RNA （shRNA）.Methods Four different SNCG shRNA oligonucleotides were designed and chemically synthesized to construct mammalian expression vectors. These vectors were then stably transfected into a breast cancer MCF-7 cell line to knockdown SNCG expression. After SNCG knockdown was confirmed, the stable cell lines were inoculated into nude mice. SNCG mRNA and protein expressions were analyzed by semi-quantitative reverse transcription-polymerase chain reaction （RT-PCR） and immunohistochemistry, respectively in both the stable cell lines and xenografts.Results All four SNCG shRNA constructs significantly reduced SNCG mRNA and protein levels in MCF-7 cells, as compared to the unrelated sequence control shRNA and the liposome control mice （P〈0.05）. SNCG-knockdown MCF-7cells formed significantly smaller tumor masses than cells expressing the unrelated sequence control or the liposome control mice （P〈0.05）.Conclusion SNCG shRNA effectively suppressed breast cancer cell formation in vivo and may be a useful clinical strategy to control breast cancer展开更多
Background There is a significant association between obesity and breast cancer, which is possibly due to the expression of leptin. Therefore, it is important to clarify the role of leptin/ObR （leptin receptor） sig...Background There is a significant association between obesity and breast cancer, which is possibly due to the expression of leptin. Therefore, it is important to clarify the role of leptin/ObR （leptin receptor） signaling during the progression of human breast cancer. Methods Nude mice with xenografts of MCF-7 human breast cancer cells were administered recombinant human leptin subcutaneous via injection around the tumor site. Mice in the experimental group were intratumorally injected with ObR-RNAi-lentivirus, while negative control group mice were injected with the same dose of negative-lentivirus. Tumor size was blindly measured every other day, and mRNA and protein expression levels of ObR, estrogen receptor a （ERa）, and vascular endothelial growth factor （VEGF） for each group were determined.Results Knockdown of ObR-treated xenografted nude mice with a high leptin microenvironment was successfully established. Local injection of ObR-RNAi-lentivirus significantly suppressed the established tumor growth in nude mice. ObR level was significantly lower in the experimental group than in the negative control group, while the amounts of ERα and VEGF expression were significantly lower in the leptin group than in the control group （P 〈0.01 for all）.Conclusions Inhibition of leptin/ObR signaling is essential to breast cancer proliferation and possible crosstalk between ObR and ERa, and VEGF, and may lead to novel therapeutic treatments aiming at targeting ObR in breast cancers.展开更多
Background It is important to identify the multiple sites of leptin activity in obese women with breast cancer.In this study,we examined the effect of exogenous human leptin on heat shock protein 70 （HSP70） expressi...Background It is important to identify the multiple sites of leptin activity in obese women with breast cancer.In this study,we examined the effect of exogenous human leptin on heat shock protein 70 （HSP70） expression in MCF-7 human breast cancer cells and in a breast carcinoma xenograft model of nude mice.Methods We cultured MCF-7 human breast cancer cells and established nude mice bearing xenograffs of these cells,and randomly divided them into experimental and control groups.The experimental group was treated with human leptin,while the control group was treated with the same volume of normal saline.A real-time reverse transcriptase-polymerase chain reaction （RT-PCR） assay was developed to quantify the mRNA expression of HSP70 in the MCF-7 human breast cancer cells and in tumor tissues.Western blotting analysis was applied to quantify the protein expression of HSP70 in the MCF-7 cells.Immunohistochemical staining was done to assess the positive rate of HSP70 expression in the tumor tissues.Results Leptin activated HSP70 in a dose-dependent manner in vitro：leptin upregulated significantly the expression of HSP70 at mRNA and protein levels in MCF-7 human breast cancer cells （P 〈0.001）.There was no significant difference in expression of HSP70 mRNA in the implanted tumors between the leptin-treated group and the control group （P〉0.05）.Immunohistochemical staining revealed no significant difference in tumor HSP70 expression between the leptin-treated group and the control group （P〉0.05）.Conclusions A nude mouse xenograft model can be safely and efficiently treated with human leptin by subcutaneous injections around the tumor.HSP70 may be target of leptin in breast cancer.Leptin can significantly upregulate the expression of HSP70 in a dose-dependent manner in vitro.展开更多
文摘Background Overexpression of breast cancer-specific gene 1 （SNCG） is associated with poor prognosis in advanced breast cancer patients. This study aimed to determine the effects of SNCG knockdown in breast cancer cells by using small hairpin RNA （shRNA）.Methods Four different SNCG shRNA oligonucleotides were designed and chemically synthesized to construct mammalian expression vectors. These vectors were then stably transfected into a breast cancer MCF-7 cell line to knockdown SNCG expression. After SNCG knockdown was confirmed, the stable cell lines were inoculated into nude mice. SNCG mRNA and protein expressions were analyzed by semi-quantitative reverse transcription-polymerase chain reaction （RT-PCR） and immunohistochemistry, respectively in both the stable cell lines and xenografts.Results All four SNCG shRNA constructs significantly reduced SNCG mRNA and protein levels in MCF-7 cells, as compared to the unrelated sequence control shRNA and the liposome control mice （P〈0.05）. SNCG-knockdown MCF-7cells formed significantly smaller tumor masses than cells expressing the unrelated sequence control or the liposome control mice （P〈0.05）.Conclusion SNCG shRNA effectively suppressed breast cancer cell formation in vivo and may be a useful clinical strategy to control breast cancer
基金This study was supported by a grant from the National Natural Science Foundation of China （No. 30772121） and the Beijing Natural Science Foundation （No. 7092024）.
文摘Background There is a significant association between obesity and breast cancer, which is possibly due to the expression of leptin. Therefore, it is important to clarify the role of leptin/ObR （leptin receptor） signaling during the progression of human breast cancer. Methods Nude mice with xenografts of MCF-7 human breast cancer cells were administered recombinant human leptin subcutaneous via injection around the tumor site. Mice in the experimental group were intratumorally injected with ObR-RNAi-lentivirus, while negative control group mice were injected with the same dose of negative-lentivirus. Tumor size was blindly measured every other day, and mRNA and protein expression levels of ObR, estrogen receptor a （ERa）, and vascular endothelial growth factor （VEGF） for each group were determined.Results Knockdown of ObR-treated xenografted nude mice with a high leptin microenvironment was successfully established. Local injection of ObR-RNAi-lentivirus significantly suppressed the established tumor growth in nude mice. ObR level was significantly lower in the experimental group than in the negative control group, while the amounts of ERα and VEGF expression were significantly lower in the leptin group than in the control group （P 〈0.01 for all）.Conclusions Inhibition of leptin/ObR signaling is essential to breast cancer proliferation and possible crosstalk between ObR and ERa, and VEGF, and may lead to novel therapeutic treatments aiming at targeting ObR in breast cancers.
基金This study was supported by a grant from the National Natural Science Foundation of China （No.30772121）.
文摘Background It is important to identify the multiple sites of leptin activity in obese women with breast cancer.In this study,we examined the effect of exogenous human leptin on heat shock protein 70 （HSP70） expression in MCF-7 human breast cancer cells and in a breast carcinoma xenograft model of nude mice.Methods We cultured MCF-7 human breast cancer cells and established nude mice bearing xenograffs of these cells,and randomly divided them into experimental and control groups.The experimental group was treated with human leptin,while the control group was treated with the same volume of normal saline.A real-time reverse transcriptase-polymerase chain reaction （RT-PCR） assay was developed to quantify the mRNA expression of HSP70 in the MCF-7 human breast cancer cells and in tumor tissues.Western blotting analysis was applied to quantify the protein expression of HSP70 in the MCF-7 cells.Immunohistochemical staining was done to assess the positive rate of HSP70 expression in the tumor tissues.Results Leptin activated HSP70 in a dose-dependent manner in vitro：leptin upregulated significantly the expression of HSP70 at mRNA and protein levels in MCF-7 human breast cancer cells （P 〈0.001）.There was no significant difference in expression of HSP70 mRNA in the implanted tumors between the leptin-treated group and the control group （P〉0.05）.Immunohistochemical staining revealed no significant difference in tumor HSP70 expression between the leptin-treated group and the control group （P〉0.05）.Conclusions A nude mouse xenograft model can be safely and efficiently treated with human leptin by subcutaneous injections around the tumor.HSP70 may be target of leptin in breast cancer.Leptin can significantly upregulate the expression of HSP70 in a dose-dependent manner in vitro.
