Inhibition of the Warburg effect with a natural compound reveals a novel measurement for determining the metastatic potential of breast cancers

Metabolism is an important differentiating feature of cancer cells. Lactate dehydrogenases (LDH) A/B are metabolically important proteins and are involved in the critical step of inter-conversion of lactate to pyruvate. Panepoxydone (PP), a natural NF-kB inhibitor, significantly reduces the oxygen consumption and lactate production of MCF-7 and triple negative (MDA-MB-231, MDA-MB-468 and MDA-MB-453) breast cancer cells. We further observed that PP inhibited mitochondrial membrane potential and the ATP synthesis using flow cytometry. PP also up-regulated LDH-B and down-regulated LDH-A expression levels in all breast cancer cells to similar levels observed in HMEC cells. Over-expression of LDH-B in cancer cell lines leads to enhanced apoptosis, mitochondrial damage, and reduced cell migration. Analyzing the patient data set GDS4069 available on the GEO website, we observed 100% of non TNBC and 60% of TNBC patients had less LDH-B expression than LDH-A expression levels. Herein we report a new term called Glycolytic index, a novel method to calculate utilization of oxidative phosphorylation in breast cancer cells through measuring the ratio of the LDH-B to LDH-A. Furthermore, inhibitors of NF-kB could serve as a therapeutic agent for targeting metabolism and for the treatment of triple negative breast cancer.     

lncRNA HULC在膀胱癌组织中的表达及其对5637细胞恶性生物学行为的影响

目的:探讨长链非编码RNA(lncRNA)HULC在膀胱癌组织中的表达及其与患者临床病理特征的关系,以及沉默HULC对膀胱癌5637细胞增殖、凋亡、迁移与侵袭的影响。方法:选取2014年6月至2017年12月郑州人民医院手术切除的102例膀胱癌患者的癌及癌旁组织标本,以及人膀胱癌细胞株5637和人正常膀胱上皮细胞株SV-HUC-1,用qPCR法检测膀胱癌组织及细胞中HULC的表达,并分析HULC表达与膀胱癌患者临床病理特征的相关性,通过Kaplan-Meier生存曲线评估HULC对预后的影响。利用siRNA干扰技术将si-HULC、si-NC质粒转染进5637细胞中,分别采用CCK-8法、流式细胞术、划痕愈合实验及Transwell小室法检测沉默HULC对5637细胞增殖、凋亡、迁移及侵袭的影响。结果:膀胱癌组织中HULC的表达水平显著高于癌旁组织(P<0.01),HULC表达水平与患者肿瘤分级、肿瘤分期及淋巴结转移相关联(均P<0.05),HULC高表达患者的OS与PFS明显低于低表达者(均P<0.05)。5637细胞中HULC的表达水平明显高于SV-HUC-1细胞(P<0.01),沉默HULC后的5637细胞的增殖、迁移和侵袭能力均显著降低(均P<0.01)、细胞凋亡率明显升高(P<0.01)。结论:lncRNA HULC在膀胱癌组织及5637细胞中均高表达,沉默HULC表达可抑制膀胱癌细胞的增殖、迁移和侵袭能力并促进凋亡。     

Endostatin expression by MDA-MB-435 breast cancer cells effectively inhibits tumor growth

Tumors must induce the formation of new blood vessels in order to grow and metastasize. Endostatin, a cleaved product of collagen XVIII, inhibits endothelial cell proliferation and suppresses tumor growth and metastases. Several recent reports have questioned the efficacy of endostatin as a tumor suppressor in experimental animals. Our objective was to determine whether endostatin expression in breast cancer cells inhibits neovascularization and tumor growth in nude mice. MDA-MB-435 cells were transfected with an endostatin expression vector while control cells were transfected with an empty vector. Endostatin expression and secretion were confirmed by RT-PCR and a dot blot assay. No differences were observed in the growth rates of the endostatin-expressing and control clones in vitro. When injected into male and female nude mice, tumors from the control clones increased in size 10-15 fold over 8-10 weeks. In contrast, the endostatin clones formed small tumors which did not increase in size after the first 3 weeks. The endostatinderived tumors had a significantly higher apoptotic index (5.6%) compared to controls (2.0%) and showed a marked reduction in vascularization. In conclusion, expression of endostatin in MDA-MB-435 breast cancer cells effectively suppressed breast tumor growth by inhibiting angiogenesis and increasing apoptosis.     

Different effects of LDH-A inhibition by oxamate in non-small cell lung cancer cells

Higher rate of glycolysis has been long observed in cancer cells, as a vital enzyme in glycolysis, lactate dehydrogenase A (LDH-A) has been shown with great potential as an anti-cancer target. Accumulating evidence indicates that inhibition of LDH-A induces apoptosis mediated by oxidative stress in cancer cells. To date, it''s still unclear that whether autophagy can be induced by LDH-A inhibition. Here, we investigated the effects of oxamate, one classic inhibitor of LDH-A in non-small cell lung cancer (NSCLC) cells as well as normal lung epithelial cells. The results showed that oxamate significantly suppressed the proliferation of NSCLC cells, while it exerted a much lower toxicity in normal cells. As previous studies reported, LDH-A inhibition resulted in ATP reduction and ROS (reactive oxygen species) burst in cancer cells, which lead to apoptosis and G₂/M arrest in H1395 cells. However, when being exposed to oxamate, A549 cells underwent autophagy as a protective mechanism against apoptosis. Furthermore, we found evidence that LDH-A inhibition induced G₀/G₁ arrest dependent on the activation of GSK-3β in A549 cells. Taken together, our results provide useful clues for targeting LDH-A in NSCLC treatment and shed light on the discovery of molecular predictors for the sensitivity of LDH-A inhibitors.     

Mus81基因沉默对MDA-MB-231乳腺癌细胞增殖、凋亡及裸鼠成瘤能力的影响北大核心

目的:分析甲磺酸盐及紫外线敏感性81号基因(Mus81)在乳腺癌组织中的表达水平,观察Mus81基因敲减对三阴性乳腺癌细胞MDA-MB-231增殖、凋亡和裸鼠移植瘤形成能力的影响。方法:从TCGA数据库下载乳腺癌样本基因表达数据,应用perl及R软件整理数据筛选出每个样本Mus81基因表达量。通过慢病毒介导的小干扰RNA(short interfering RNA,siRNA)技术构建Mus81基因敲减的MDA-MB-231乳腺癌细胞系(即Mus81敲减组)和阴性对照组MDA-MB-231乳腺癌细胞系,以实时定量PCR法检测Mus81基因的敲减效率,再以MTT检测实验、克隆形成实验、细胞流式检测及实时定量PCR法检测两组MDA-MB-231细胞的生长、增殖、细胞周期分布、凋亡水平及Mus81下游基因表达水平。最后,向BALB/c裸鼠右侧腋下注射Mus81基因敲减组和阴性对照组MDA-MB-231乳腺癌细胞,观察Mus81基因沉默对MDA-MB-231细胞在裸鼠中成瘤能力的影响。结果:Mus81基因在乳腺癌组织中的平均表达量明显高于癌旁组织(P<0.05)。Mus81基因敲减组MDA-MB-231细胞中Mus81基因的表达水平明显低于阴性对照组(P<0.05),Mus81基因的敲减效率达70.7%。较之阴性对照组,Mus81基因敲减组MDA-MB-231细胞的生长速度明显减缓(P<0.05);形成的细胞克隆数也明显下降(P<0.05);细胞凋亡水平、G2/M期细胞比例则明显升高(P<0.05)。STC2等Mus81下游基因的表达水平在两组MDA-MB-231细胞间也有明显差异(P<0.05)。裸鼠成瘤实验显示,Mus81基因敲减组形成的裸鼠瘤体体积和重量均明显低于阴性对照组(P<0.05)。结论:Mus81基因在乳腺癌组织中的表达明显升高,且可能通过调控STC2等下游基因的表达促进三阴性乳腺癌细胞的生长增殖及裸鼠体内成瘤能力并抑制其凋亡,提示其可能是一个潜在的乳腺癌治疗靶点。     

Pilot study demonstrating metabolic and anti-proliferative effects of in vivo anti-oxidant supplementation with N-Acetylcysteine in Breast Cancer

BackgroundHigh oxidative stress as defined by hydroxyl and peroxyl activity is often found in the stroma of human breast cancers. Oxidative stress induces stromal catabolism, which promotes cancer aggressiveness. Stromal cells exposed to oxidative stress release catabolites such as lactate, which are up-taken by cancer cells to support mitochondrial oxidative phosphorylation. The transfer of catabolites between stromal and cancer cells leads to metabolic heterogeneity between these cells and increased cancer cell proliferation and reduced apoptosis in preclinical models. N-Acetylcysteine (NAC) is an antioxidant that reduces oxidative stress and reverses stromal catabolism and stromal-carcinoma cell metabolic heterogeneity, resulting in reduced proliferation and increased apoptosis of cancer cells in experimental models of breast cancer. The purpose of this clinical trial was to determine if NAC could reduce markers of stromal-cancer metabolic heterogeneity and markers of cancer cell aggressiveness in human breast cancer.MethodsSubjects with newly diagnosed stage 0 and I breast cancer who were not going to receive neoadjuvant therapy prior to surgical resection were treated with NAC before definitive surgery to assess intra-tumoral metabolic markers. NAC was administered once a week intravenously at a dose of 150 mg/kg and 600 mg twice daily orally on the days not receiving intravenous NAC. Histochemistry for the stromal metabolic markers monocarboxylate transporter 4 (MCT4) and caveolin-1 (CAV1) and the Ki67 proliferation assay and TUNEL apoptosis assay in carcinoma cells were performed in pre- and post-NAC specimens.ResultsThe range of days on NAC was 14–27 and the mean was 19 days. Post-treatment biopsies showed significant decrease in stromal MCT4 and reduced Ki67 in carcinoma cells. NAC did not significantly change stromal CAV1 and carcinoma TUNEL staining. NAC was well tolerated.ConclusionsNAC as a single agent reduces MCT4 stromal expression, which is a marker of glycolysis in breast cancer with reduced carcinoma cell proliferation. This study suggests that modulating metabolism in the tumor microenvironment has the potential to impact breast cancer proliferation.     

GST-pi expression correlates with oxidative stress and apoptosis in breast cancer

Glutathione S-transferase (GST) is known to play a key role in the detoxification and reduction of reactive oxygen species (ROS). Thus, we assessed GST activity and GST-pi expression in relation to oxidative stress and apoptosis in breast cancer. Tumor tissues from 32 breast cancer patients were evaluated for GST activity and thiobarbituric acid reactive substances (TBARS) that are by-products of oxidative stress. Four-micron sections of formalin-fixed, paraffin embedded tumors were stained immunohistochemically with anti-GST-pi. Apoptotic cells were detected by in situ end labeling of DNA fragments using a commercial kit. TBARS levels were significantly higher in breast cancers of older patients. GST-pi expression was up-regulated in breast cancers that exhibited higher oxidative stress and associated with higher GST activity. Apoptosis in GST-pi negative tumors was not correlated with GST activity, but GST-pi positive tumors within the same range of oxidative stress showed a reduction in apoptosis as well as an increased GST activity. This correlation was absent in GST-pi positive tumors experiencing higher oxidative stress. GST-pi expression may influence the level of GST activity and delay apoptosis in breast cancer. However, GST-pi expression in tumors with higher levels of oxidative stress may not be sufficient to abrogate the deleterious effects of ROS.     

p33^（ING1）基因和MVD在乳腺癌中的表达及其意义

目的探讨p33ING1基因、MVD在乳腺癌中表达的意义及其相互关系。方法应用Envision免疫组化法对115例乳腺癌标本进行p33ING1基因和MVD表达检测。结果p33ING1在乳腺癌的阳性表达率为61.7%,与肿瘤浸润分化程度、淋巴结转移及激素受体呈明显负相关。MVD与肿瘤组织学分级及腋下淋巴结转移呈明显正相关,与肿瘤的大小、年龄及激素受体状况无相关性。结论p33ING1阴性者MVD表达明显高于p33ING1阳性者,呈负相关,p33ING1的过度表达及MVD的减少共同参与了抑制细胞生长、促进细胞凋亡的过程。     

Expression of the hemochromatosis gene modulates the cytotoxicity of doxorubicin in breast cancer cells

The antineoplastic agent doxorubicin inhibits cell growth through mechanisms that include an interaction with iron, resulting in the generation of cytotoxic reactive oxygen species (ROS). Prior studies have shown that the wild-type hemochromatosis gene (wt HFE) may downregulate iron uptake and alter iron homeostasis in cells. We therefore tested the hypothesis that expression of wt HFE would affect the cytotoxicity of doxorubicin. Human breast cancer MCF-7 cells were transfected with an expression plasmid for a FLAG-tagged wt HFE gene [fwtHFE(+) cells], to examine the impact of wt HFE expression on doxorubicin-induced apoptosis. Our results show that, in MCF-7 cells, fwtHFE expression resulted in a reduction in cellular iron uptake and a decrease in the growth inhibitory effects of doxorubicin. Two micromolar doxorubicin inhibited the growth of fwtHFE(+) and fwtHFE(-) MCF-7 cells by 34% and 61%, respectively. In parallel, doxorubicin induced caspase-3-like activity in fwtHFE(-) cells, but not in fwtHFE(+) cells. On analysis with a DCF fluorescence assay, ROS could be detected in fwtHFE(-) cells but not in fwtHFE(+) cells exposed to doxorubicin. Western blot analysis of breast biopsy samples from patients revealed immunoreactive HFE and transferrin receptor proteins in both normal and malignant breast tissues. Our studies suggest that HFE expression and its consequent effect on cellular iron homeostasis may modulate doxorubicin-induced oxidative stress and apoptosis in breast cancer cells. Further investigation is warranted to determine whether HFE expression in tumor cells impacts on the clinical efficacy of doxorubicin.     

miR-199a-3p在乳腺癌中的表达及其作用

背景与目的：多种微小RNA(microRNA,miRNA)在乳腺癌中异常表达,在乳腺癌的发生、发展中起重要作用。miRNA可能是治疗乳腺癌的新靶点。该研究旨在探讨miR-199a-3p在乳腺癌中的表达水平,及其对乳腺癌癌细胞增殖和凋亡的影响。方法：运用实时定量聚合酶链式反应(quantitative real-time polymerase chain reaction,QRT-PCR)检测乳腺癌患者癌组织、癌旁正常组织、人乳腺癌细胞和人乳腺细胞中miRNA-199a-3p的表达水平,miR-199a-3p mimic(或inhibitor)转染乳腺癌细胞MDA-MB-231过表达(或沉默)miR-199a-3p的表达后,通过MTT法检测细胞增殖能力,Hoechst染色法和caspase-3活力测试检测细胞凋亡情况。结果：相对癌旁正常组织和人正常乳腺细胞,miR-199a-3p在乳腺癌患者癌组织和人乳腺癌细胞中表达下调。在MDA-MB-231中转染miR-199a-3p mimic过表达miR-199a-3p可抑制细胞增殖,促进其凋亡;在MDA-MB-231中转染miR-199a-3p inhibitor沉默miR-199a-3p可促进细胞增殖,抑制其凋亡。结论：miR-199a-3p在乳腺癌中表达下调,并通过调节乳腺癌细胞增殖和凋亡发挥抑癌作用。     

Overexpression of NDC80 is correlated with prognosis of pancreatic cancer and regulates cell proliferation

Aims: NDC80/Hec1, one of four proteins of the outer kinetochore NDC80 complex, is involved in the tumorigenesis of a variety of cancers. In this study, we focused on that NDC80 is overexpressed in human pancreatic cancer and investigates the role of NDC80-knockdown in pancreatic cancer cells proliferation. Materials and methods: We determined the expression levels of NDC80 on both mRNA and protein levels in fresh pancreatic cancer tissues and cells by quantitative real-time polymerase chain reaction and immunoblotting, respectively. Furthermore, protein level of NDC80 was identified using immunochemistry in paraffin-embedded tumor specimen, with correlation between NDC80 expression and various clinicopathological parameters evaluated. The role of NDC80 in pancreatic cancer cells (Panc-1) growth was investigated by lentivirus-mediated silencing of NDC80. The effect of NDC80 deletion on cell proliferation was analyzed by MTT assay and clone formation assay, while cell cycle distributions and apoptosis were analyzed by flow cytometry. Results: The mRNA and protein of NDC80 were overexpressed in pancreatic cancer tissues and cells. The statistical analysis based on immunohistochemical evaluation suggested that NDC80 overexpression was signifi cantly associated with clinicopathological parameters including pathological T staging and N staging, which may be served as an predictor for poor outcomes. The silencing of NDC80 in Panc-1 cells could suppress cell proliferation and colony formation. Furthermore, the NDC80-siRNA infected Panc-1 cells lead to cell cycle arrest at G2/M phase and induction of apoptosis. Conclusion: These results demonstrated that NDC80 plays an essential role in the tumorigenesis of pancreatic cancer, and might serve as potential prognostic and therapeutic target for treatment of pancreatic cancer.     

miR-133通过Notch1信号通路调控BCAR4对乳腺癌迁移和侵袭的影响

目的:探讨微小核糖核酸-133(miR-133)调控乳腺癌雌激素耐受基因4(breast cancer anti-estrogen resistance4,BCAR4)对乳腺癌细胞迁移和侵袭的影响及其机制.方法:采集2006年1至12月在郑州大学附属肿瘤医院接受手术切除治疗的80例乳腺癌患者的乳腺癌和相应癌旁组织.RT-PCR检测乳腺癌和癌旁组织BCAR4和miR-133的表达;双荧光素酶检测BCAR4和miR-133之间的关联;划痕实验和Transwell实验分别检测沉默BCAR4或沉默BCAR4和miR-133后乳腺癌MCF-7细胞的迁移和侵袭能力;Western blotting检测Notch1信号通路相关蛋白的表达;裸鼠皮下成瘤实验检测沉默BCAR4对MCF-7细胞成瘤能力的影响;生物统计学分析BCAR4表达和乳腺癌患者临床病理参数及生存率的关系.结果:乳腺癌组织中BCAR4表达显著高于癌旁组织(P＜0.05);双荧光素酶实验显示BCAR4可以调控miR-133的表达;沉默BCAR4表达可以抑制乳腺癌MCF-7细胞的迁移和侵袭;沉默miR-133和BCAR4表达的MCF-7细胞的迁移率和穿膜细胞数显著高于仅沉默BCAR4表达的MCF-7细胞[迁移率(92.31±8.64)％ vs(52.61±5.12)％,P＜0.05;穿膜细胞数:(171.38±12.61) vs (28.54±3.29),P＜0.01],抑制miR-133可以逆转BCAR4抑制乳腺癌MCF-7细胞迁移、侵袭能力;沉默BCAR4组裸鼠成瘤的体积和质量都显著减小;沉默BCAR4的MCF-7细胞的Notch1通路相关蛋白表达水平明显下调;BCAR4表达与乳腺癌的病理分期及淋巴结转移显著相关,BCAR4高表达患者生存率较BCAR4低表达患者低.结论:乳腺癌MCF-7细胞的侵袭和迁移受到BCAR4和miR-133的双重调控,miR-133可能通过Notch1信号通路调节BCAR4对乳腺癌细胞迁移和侵袭的影响,可为乳腺癌分子靶向治疗及乳腺癌耐药机制的研究提供思路.     

Galectin-3 在人乳腺癌组织中的表达及对MCF-7 细胞恶性生物学行为的影响

目的：探讨半乳凝集素-3（galectin-3）蛋白在人乳腺癌组织中的表达规律及沉默galectin-3 基因后对乳腺癌MCF-7 细胞迁移、侵袭和凋亡的影响。方法：收集2014 年2 月至2018 年2 月邢台市人民医院手术切除的15 例乳腺癌患者癌组织及其癌旁组织,另外采集该医院和河北医科大学附属第四医院组织石蜡切片100 份,利用Western blotting 检测15 例乳腺癌患者的癌组织及癌旁组织中galectin-3 蛋白相对表达水平,用免疫组织化学法检测galectin-3 蛋白在100 例乳腺癌石蜡标本切片中的表达水平,并分析其表达与患者临床病理特征的关系。将galectin-3 siRNA 转染至MCF-7 细胞中,用qPCR 法和Western blotting 分别检测galectin-3 mRNA和蛋白的表达水平;用Transwell 小室法和流式细胞术分别检测galectin-3 基因沉默后对MCF-7 细胞迁移、侵袭和凋亡的影响。结果：在乳腺癌组织中galectin-3 蛋白表达水平显著高于癌旁组织（P<0.05）;乳腺癌组织中galectin-3 蛋白阳性表达率为67.00%,其表达水平在淋巴结转移、激素受体（ER、PR）阴性组中显著升高（均P<0.05）,且随TNM分期和组织学分级的升高而升高（均P<0.05）。转染galectin-3 siRNA 后,能显著降低MCF-7 细胞galectin-3 mRNA和蛋白的表达水平、迁移和侵袭能力（均P<0.05）,提高细胞的凋亡率（P<0.05）。结论：Galectin-3 在乳腺癌组织中高表达,沉默galectin-3 表达后抑制MCF-7 细胞的迁移和侵袭、诱导细胞凋亡,可作为乳腺癌生物治疗的一个新靶点。     

The tumor suppressor Smad4 is required for transforming growth factor beta-induced epithelial to mesenchymal transition and bone metastasis of breast cancer cells

Transforming growth factor beta (TGF-beta) can act as suppressor and promoter of cancer progression. Intracellular Smad proteins (i.e., receptor regulated Smads and common mediator Smad4) play a pivotal role in mediating antimitogenic and proapoptotic effects of TGF-beta, but their function in TGF-beta-induced invasion and metastasis is unclear. Here, we have investigated the role of Smad4 in a cellular and mouse model for TGF-beta-induced breast cancer progression. Consistent with its tumor suppressor function, specific silencing of Smad4 in NMuMG mammary gland epithelial cells using small hairpin RNA (shRNA)-expressing RNAi vectors strongly mitigated TGF-beta-induced growth inhibition and apoptosis. Smad4 knockdown also potently inhibited TGF-beta-induced epithelial to mesenchymal transition of NMuMG cells as measured by morphologic transformation from epithelial to fibroblast-like cells, formation of stress fibers, inhibition of E-cadherin expression, and gain of expression of various mesenchymal markers. Furthermore, we show that knockdown of Smad4 in MDA-MB-231 breast cancer cells strongly inhibited the frequency of bone metastasis in nude mice by 75% and significantly increased metastasis-free survival. Communication of MDA-MB-231 cells with the bone microenvironment, which is needed for optimal tumor cell growth and metastasis, may be affected in Smad4 knockdown cells as TGF-beta-induced expression of interleukin 11 was attenuated on Smad4 knockdown. Taken together, our results show that Smad4 plays an important role in both tumor suppression and progression of breast cancer cells.     

Knockdown of the c-Jun-N-terminal kinase expression by siRNA inhibits MCF-7 breast carcinoma cell line growth

We have examined the effect of two small interference RNA against Jnk-1 and Jnk-2 in the breast cancer cell line MCF-7. The expression of the JNK-1 and JNK-2 is frequently elevated in breast cancer and is a frequent genetic abnormality in this malignancy. For a better understanding of its role in maintaining the malignant phenotype, we used small RNA interference (siRNA) directed against Jnk-1 or Jnk-2. We made control and Jnk-1 and Jnk-2 siRNA using vector plasmid, which was then transfected to reduce its expression in MCF-7 cells. We assessed the effects of JNK-1 or JNK-2 silencing on cell growth by western blot analysis, soft agar assay, cell proliferation assay, cell viability by MTT assay and caspase assay in vitro. Our data showed that siRNA against Jnk-1 or Jnk-2 markedly and durably reduced its expression in MCF-7 cells by up to 70%, decreased the growth rate of MCF-7 cells, inhibited colony formation in soft agar and significantly reduced cell growth in MCF-7 carcinoma culture cell line. We also found that depletion of JNK-1/2 in this manner promoted apoptosis of MCF-7 cells upon serum withdrawal. In addition, we found that MCF-7 cells did not exhibit any caspase-3 activity. In conclusion, we observed that JNK-1 and JNK-2 have a pivotal function in the development of breast cancer. Our data show that decreasing the JNK-1 or JNK-2 protein level in MCF-7 cells by siRNA could significantly inhibit MCF-7 cell growth in in vitro assay, and imply the therapeutic potential of siRNA on the treatment of breast cancer by targeting overexpression kinases such as JNK-1/2 and might be a potential therapeutic target for human breast cancer.     

RNA干扰MDM2下调人乳腺癌细胞中VEGF的合成并抑制肿瘤血管的生成

目的 探讨小干扰RNA（small interfering RNA, siRNA）抑制人乳腺癌细胞中鼠双微粒体2 （murine double minute 2, MDM2）的表达对癌细胞中血管内皮生长因子（vascular endothelial growth factor, VEGF）合成以及裸鼠移植瘤组织内血管生成的影响。方法 根据MDM2已知的cDNA序列设计并转录合成特异性siRNA,转染高表达MDM2的人乳腺癌MDA-MB-468细胞,低氧培养后应用蛋白质印迹法和ELISA法检测肿瘤细胞及其上清液中VEGF的水平。构建裸鼠乳腺癌移植瘤模型,观察MDM2沉默后肿瘤生长情况,蛋白质印迹法、免疫组织化学及ELISA方法检测荷瘤组织和裸鼠血清标本中的VEGF含量,并以CD34标记血管内皮细胞计数微血管密度（microvessel density, MVD）。结果 siRNA抑制MDM2表达后,MDA-MB-468细胞分泌的VEGF蛋白显著减少（P=0.006）。裸鼠移植瘤模型显示,封闭MDM2表达使荷瘤组织生长变慢（P=0.008）,且荷瘤小鼠血清VEGF水平明显减低（P=0.008）,荷瘤组织内MVD也明显降低（P=0.003）。结论 MDM2 siRNA能有效减低乳腺癌细胞中VEGF的合成,并抑制裸鼠移植瘤组织内新生血管的生成,为MDM2/VEGF途径抗肿瘤血管生成作用的研究及靶向药物开发提供了新的思路。     

Nuclear transport receptor karyopherin-α2 promotes malignant breast cancer phenotypes in vitro

Tumorigenesis and tumor progression are associated with dysfunction of the nuclear transport machinery at the level of import and export receptors (karyopherins). Recent studies have shown that the nuclear import factor karyopherin-α2 (KPNA2) is a novel prognostic marker for poor prognosis in human breast cancer. Based on the well-defined hallmarks of cancer progression, we performed a detailed in vitro characterization of the phenotypic effects caused by KPNA2 overexpression and KPNA2 silencing in benign and malignant human breast cells. KPNA2 overexpression clearly increased proliferation of MCF7 tumor cells and further led to a reduction of cell-matrix adhesion in benign MCF10A cells, whereas cell migration was significantly increased (P<0.0001) in both tumor models. Remarkably, these individual effects of KPNA2 overexpression on proliferation, cell-matrix adhesion and migration resulted in an increased colony spreading of benign MCF10A breast cells and malignant MCF7 tumor cells (P<0.001), which is a hallmark of cancer progression. Conversely, RNA interference-mediated KPNA2 silencing caused a complete inhibition of MCF7 tumor cell proliferation and migration (P<0.0001). In addition, in these experiments apoptosis was increased (P<0.05) and formation of tumor cell colonies was reduced (P<0.01). Thus, KPNA2 overexpression provoked increased aggressiveness of malignant MCF7 breast tumor cells and induced a shift in benign MCF10A breast cells toward a malignant breast cancer phenotype. In conclusion, we demonstrate for the first time in experimental tumor models that forced KPNA2 expression drives malignant features relevant for breast cancer progression, while its silencing is required for the remission of those progressive phenotypes. This study gives clear evidence that KPNA2 acts as a novel oncogenic factor in human breast cancer, in vitro.     

结肠癌T-cadherin表达水平分析与5-Aza-CdR对其表达和结肠癌细胞增殖、侵袭及凋亡的影响

背景与目的：结肠癌是临床常见恶性肿瘤，探讨抑癌蛋白T-cadherin在结肠癌中的表达情况及其与患者临床病理学特征的关系，并分析5-Aza-CdR对T-cadherin表达和结肠癌细胞增殖、侵袭及凋亡的影响。方法：收集福建医科大学附属第二医院2015—2016年40例手术切除的结肠癌组织及癌旁组织新鲜样本，并经过病理学检查验证，分别提取总RNA和总蛋白质。采用实时荧光定量聚合酶链反应（real-time fluorescence quantitative polymerase chain reaction，RTFQ-PCR）分析T-cadherin mRNA的表达，采用蛋白质印迹法（Western blot）分析T-cadherin蛋白水平，并分析T-cadherin的mRNA表达变化与患者临床病理学特征的关系。进一步以人结肠癌细胞系HT-29为研究对象，采用甲基化抑制剂5-Aza-CdR处理HT-29细胞，分别采用RTFQ-PCR和Western blot分析T-cadherin表达变化，采用细胞计数试剂盒（cell counting kit-8，CCK-8）分析细胞增殖，采用Transwell实验验证细胞侵袭能力，采用流式细胞术分析细胞凋亡。结果：T-cadherin在结肠癌组织的蛋白水平和mRNA表达均明显低于癌旁组织，其mRNA表达与淋巴结转移（F=5.316，P=0.009 3）和分化程度（F=5.807，P=0.006 4）明显相关，而与其他病理变量（包括性别、年龄、肿瘤大小和肿瘤浸润深度）无明显相关。药物5-Aza-CdR可以显著上调HT-29细胞中T-cadherin的表达水平，抑制HT-29细胞增殖、侵袭并促进细胞凋亡。结论：T-cadherin表达可能与结肠癌恶性程度密切相关，药物5-Aza-CdR处理可上调结肠癌细胞T-cadherin的表达，并抑制结肠癌细胞的增殖、迁移，促进结肠癌细胞凋亡，提示T-cadherin可能是结肠癌患者使用甲基化抑制剂5-Aza-CdR治疗的靶点。