曲古抑菌素A和紫杉醇对子宫内膜癌细胞增殖和凋亡的影响

目的: 研究曲古抑菌素A（trichostatin A,TSA）和紫杉醇（paclitaxel, PTX）对人子宫内膜癌细胞株KLE增殖和凋亡的影响。方法：TSA和PTX、卡铂（carboplatin，Carbo） 、多柔比星（doxorubicin，Dox）单独或联合作用于KLE细胞，锥虫蓝法观察药物对肿瘤细胞生长的影响；Annexin V、Hoechst染色和线粒体膜电位检测细胞凋亡；Western blotting检测肿瘤细胞凋亡信号通路中多聚ADP核糖聚合酶（PARP）、半胱天冬氨酸蛋白酶9（caspase9）和乙酰化微管蛋白的表达。结果：PTX、Carbo、Dox和TSA对KLE细胞增殖均有抑制作用，TSA和PTX联用后抑制作用最强。Annexin V染色、Hoechst染色、线粒体膜电位法和PARP、Caspase9的检测显示，单用PTX或TSA均可诱导细胞凋亡, 联合应用产生最强的协同作用。Western blotting和免疫组化分析显示，PTX和TSA均可诱导微管蛋白乙酰化，联合用药后微管蛋白乙酰化明显增加。结论: TSA和PTX联合使用有明显的协同作用，能显著抑制子宫内膜癌KLE细胞生长和诱导细胞凋亡，其机制与激活线粒体凋亡信号通路和增强微管蛋白乙酰化有关。     

A phase II study of combination paclitaxel and carboplatin in advanced nasopharyngeal carcinoma

The aim of this study was to determine the efficacy and toxicity of combination paclitaxel and carboplatin chemotherapy in patients with metastatic and/or locoregionally advanced nasopharyngeal carcinoma (NPC). Patients with metastatic and/or locoregionally advanced NPC were treated with carboplatin calculated according to an AUC of 6 mg ml/min (based on Calvert formula) given as an intravenous (i.v.) bolus, followed by paclitaxel 135 mg/ml2 given as an i.v. infusion over 3 h with standard premedication. Cycles were given 3 weekly to a maximum of six. From January 1996 to November 1997, 27 patients were entered and assessable for response and toxicity. A total of 122 cycles were given and the median number of cycles given was five. The overall response rate was 59% (16/27). There were 3 (11%) complete responses, 13 (48%) partial responses, 5 (19%) static disease and 6 (22%) progressive disease. Toxicity was mainly haematological including: grade 3/4 neutropenia (39 cycles, 32%), grade 3/4 anaemia (nine cycles, 7%), grade 3/4 thrombocytopenia (eight cycles, 7%). There were three episodes of neutropenic fever (3%). Non-haematological toxicities were mild and infrequent. Paclitaxel and carboplatin combination chemotherapy is active in NPC and has tolerable toxicity. Further study with dose escalation is required to assess its optimal efficacy.     

Epigenetic silencing of claudin-6 promotes anchorage-independent growth of breast carcinoma cells

Cancer cells often exhibit loss of functional tight junctions (TJ), and disruption of the TJ structure is associated with cancer development. However, whether loss of a certain type of claudin, an integral membrane protein of TJ, is involved in malignant phenotypes remains to be clarified. Based on a report that claudin-6 functions as a tumor suppressor for breast cancer, the authors show here that suppression of claudin-6 expression results in increased resistance to various apoptogens, and causally enhances anchorage-independent growth properties. Because claudin-6 expression is partially silenced by promoter CpG island hypermethylation in MCF7 breast carcinoma cells, a synergistic effect of a demethylator and histone deacetylase inhibitor up-regulates the expression of endogenous claudin-6, which is sufficient for apoptotic sensitization and abrogation of colony-forming efficacy. In addition, decreased expression of claudin-6 promotes cellular invasiveness and transendothelial migration, accompanied by an increase in matrix metalloproteinase activity. These data suggest that the methylator phenotype of claudin-6 may at least partially contribute to enhanced tumorigenic and invasive properties of breast carcinoma cells.     

ALDH1A1基因表达沉默对鼻咽癌细胞的增殖抑制作用

目的：探讨干扰乙醛脱氢酶1A1（ALDH1A1）基因表达后对鼻咽癌5-8F和CNE2细胞生长、增殖的影响。方法：构建ALDH1A1 siRNA 表达质粒稳定转染鼻咽癌5-8F和CNE2细胞,Western blot 检测干扰ALDH1A1基因蛋白表达水平。MTT、平板克隆、裸鼠成瘤实验检测干扰ALDH1A1基因前后鼻咽癌5-8F和CNE2细胞的增殖、克隆及成瘤能力。结果：与空白组和阴性对照组相比,干扰ALDH1A1表达后5-8F和CNE2细胞增殖、克隆及肿瘤形成能力明显受到抑制。结论：干扰ALDH1A1基因表达,可抑制鼻咽癌细胞的生长、增殖、克隆及成瘤能力。     

siRNA-mediated Erc gene silencing suppresses tumor growth in Tsc2 mutant renal carcinoma model

Silencing of gene expression by small interfering RNAs (siRNAs) is rapidly becoming a powerful tool for genetic analysis and represents a potential strategy for therapeutic product development. However, there are no reports of systemic delivery of siRNAs for stable treatment except short hairpin RNAs (shRNAs). On the other hand, there are many reports of systemic delivery of siRNAs for transient treatment using liposome carriers and others. With regard to shRNAs, a report showed fatality in mice due to oversaturation of cellular microRNA/short hairpin RNA pathways. Therefore, we decided to use original siRNA microspheres instead of shRNA for stable treatment of disease. In this study, we designed rat-specific siRNA sequences for Erc/mesothelin, which is a tumor-specific gene expressed in the Eker (Tsc2 mutant) rat model of hereditary renal cancer and confirmed the efficacy of gene silencing in vitro. Then, by using siRNA microspheres, we found that the suppression of Erc/mesothelin caused growth inhibition of Tsc2 mutant renal carcinoma cells in tumor implantation experiments in mice.     

siRNA-mediated silencing of Notch-1 enhances docetaxel induced mitotic arrest and apoptosis in prostate cancer cells

Purpose: Notch is an important signaling pathway that regulates cell fate, stem cell maintenance and theinitiation of differentiation in many tissues. It has been reported that activation of Notch-1 contributes totumorigenesis. However, whether Notch signaling might have a role in chemoresistance of prostate cancer isunclear. This study aimed to investigate the effects of Notch-1 silencing on the sensitivity of prostate cancercells to docetaxel treatment. Methods: siRNA against Notch-1 was transfected into PC-3 prostate cancer cells.Proliferation, apoptosis and cell cycle distribution were examined in the presence or absence of docetaxel byMTT and flow cytometry. Expression of p21waf1/cip1 and Akt as well as activation of Akt in PC-3 cells were detectedby Western blot and Real-time PCR. Results: Silencing of Notch-1 promoted docetaxel induced cell growthinhibition, apoptosis and cell cycle arrest in PC-3 cells. In addition, these effects were associated with increasedp21waf1/cip1 expression and decreased Akt expression and activation in PC-3 cells. Conclusion: Notch-1 promoteschemoresistance of prostate cancer and could be a potential therapeutic target.     

Nitric oxide inhibits autophagy and promotes apoptosis in hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is the second most common cause of cancer‐related mortality worldwide. The expression of nitric oxide synthase (NOS) and the inhibition of autophagy have been linked to cancer cell death. However, the involvement of serum nitric oxide (NO), the expression of NOS and autophagy have not been investigated in HCC. In the present study, we first established that the NO level was significantly higher in hepatitis B virus‐related HCC than in the liver cirrhosis control (53.60 ± 19.74 vs 8.09 ± 4.17 μmol/L, t = 15.13, P < 0.0001). Using immunohistochemistry, we found that the source of NO was at least partially attributed to the expression of inducible NOS and endothelial NOS but not neuronal NOS in the liver tissue. Furthermore, in human liver cancer cells, NO‐induced apoptosis and inhibited autophagy. Pharmacological inhibition of autophagy also induced apoptosis, whereas the induction of autophagy could ameliorate NO‐induced apoptosis. We also found that NO regulates the switch between apoptosis and autophagy by disrupting the Beclin 1/Vps34 association and by increasing the Bcl‐2/Beclin 1 interaction. Overall, the present findings suggest that increased NOS/NO promotes apoptosis through the inhibition of autophagy in liver cancer cells, which may provide a novel strategy for the treatment of HCC.     

Interferon-gamma inhibits growth of human neuroendocrine carcinoma cells via induction of apoptosis

Although biotherapy of gastroenteropancreatic neuroendocrine tumors (NET) provides excellent control for the hypersecretion syndrome, tumor regression is rarely observed, implying the need for novel antiproliferative strategies. Here, we demonstrate that human pancreatic QGP-1 NET cells express functionally intact interferon-gamma (IFN-gamma) receptors and downstream effectors, including the putative tumor suppressor interferon regulatory factor-1 (IRF-1). IFN-gamma treatment profoundly inhibited anchorage-dependent and anchorage-independent growth of QGP-1 cells. Concomitant with the onset of growth inhibition, apoptotic cells were detected in cell cycle analyses of IFN-gamma treated cultures. Apoptosis was confirmed by evaluation of DNA fragmentation and PARP cleavage. Immunoblots of IFN-gamma treated QGP-1 cells revealed a substantial upregulation of caspase-1, followed by the appearance of active proteolytic fragments of caspase-3, suggesting that autocatalytic activation of caspase-1 might initiate the caspase cascade. Apoptosis induction by IFN-gamma was also observed in two of four primary cultures established from tumors of patients with for- and midgut NETs, respectively. Taken together our results characterize IFN-gamma as a potent proapoptotic stimulus in a subset of gastrointestinal NETs and suggest an IRF-1 mediated induction of caspase-1 as a relevant underlying mechanism. Based on these results, the potential of IFN-gamma in experimental biotherapeutic treatment of NETs can be further explored.     

siＲNA 介导的eIF3b基因沉默抑制乳腺癌细胞MCF-7的侵袭和迁移

目的:探讨siＲNA介导的eIF3b基因沉默对乳腺癌细胞MCF-7侵袭和迁移能力的影响。方法:设计eIF3b基因的小分子干扰RNA(siRNA)片段,脂质体介导转染入乳腺癌细胞株MCF-7,转染分3个组:I组(空白对照组)、II组(转染非特异性对照组)和III组（转染eIF3b-siRNA组）。应用qＲT-PCＲ和Western blotting免疫印迹法检测转染前后eIF3b基因mＲNA和蛋白表达水平;运用Matrigel 胶模型细胞迁移和侵袭实验检测MCF-7细胞迁移和侵袭能力的变化。结果:与I组（1.09±0.19）、II组（1.05±0.17）相比,III组eIF3b 蛋白表达水平（0.45±0.06）明显下降,差异具有统计学意义(P＜0.05),I组和II组eIF3b蛋白表达水平比较,差异无统计学意义(P＞0.05)。III组eIF3b mRNA相对表达水平为0.54±0.08,明显低于I组(1.12±0.16)和II组(1.08±0.18),差异有统计学意义（P＜0.05）,I组和II组eIF3b mRNA表达比较,差异无统计学意义(P＞0.05)。细胞迁移实验中,III组细胞明显少于I组和II组(P＜0.05);细胞侵袭实验中,III组穿过人工基底膜的细胞明显少于I组和II组(P＜0.05)。结论:下调eIF3b表达可明显抑制乳腺癌细胞侵袭和迁移。     

Induction of apoptosis in tumor cells by siRNA-mediated silencing of the livin/ML-IAP/KIAP gene

Increased resistance to apoptosis is a hallmark of many tumor cells. The functional inhibition of specific antiapoptotic factors may provide a rational basis for the development of novel therapeutic strategies. We investigated here whether the RNA interference (RNAi) technology could be used to increase the apoptotic susceptibility of cancer cells. As a molecular target, we chose the antiapoptotic livin (ML-IAP, KIAP) gene, which is expressed in a subset of human tumors. We identified vector-borne small interfering (si)RNAs, which could efficiently block endogenous livin gene expression. Silencing of livin was associated with caspase-3 activation and a strongly increased apoptotic rate in response to different proapoptotic stimuli, such as doxorubicin, UV-irradiation, or TNFalpha. The effects were specific for Livin-expressing tumor cells. Our results (i) provide direct evidence that the intracellular interference with livin gene expression resensitizes human tumor cells to apoptosis, (ii) define the livin gene as a promising molecular target for therapeutic inhibition, and (iii) show that the livin gene is susceptible to efficient and specific silencing by the siRNA technology.     

MTA1 promotes nasopharyngeal carcinoma growth in vitro and in vivo

Background

The prognostic value of metastasis-associated gene 1 (MTA1) in nasopharyngeal carcinoma (NPC) has been suggested. However, there is still no direct evidence that MTA1 promotes NPC growth in vivo. In this study, we aimed to investigate the function of MTA1 in the regulation of NPC cell proliferation and tumorigenesis in vitro and in vivo.

Methods

Stable MTA1 knockdown or overexpression NPC cell lines were employed. The effects of MTA1 depletion or overexpression on cell proliferation, colony formation, cell cycle progression were examined by MTT, colony formation and flow cytometry assay. The effects of MTA1 depletion on tumor growth in vivo were examined in mouse xenograft model.

Results

MTA1 knockdown or overexpression drastically changed the proliferation, colony formation and cell cycle of NPC cells in vitro. MTA1 depletion significantly suppressed NPC tumorigenesis in vivo.

Conclusion

MTA1 promotes NPC cell proliferation via enhancing G1 to S phase transition, leading to increased tumor growth. Targeting MTA1 is a promising approach to reduce tumor burden of NPC.     

CAAP1抑制肝癌HepG2细胞凋亡而促进其增殖、迁移和侵袭

目的:探讨CAAP1对肝癌HepG2细胞凋亡、增殖、迁移和侵袭的影响及其作用机制.方法:构建CAAP1过表达载体pcDNA3/CAAP1和敲降载体pSilencer 2.l-U6 neo/shR-CAAPl,转染肝癌HepG2细胞后,qPCR和WB实验分别检测CAAP1mRNA和蛋白的表达水平.实验分为过表达对照组(p...     

Klotho inhibits growth and promotes apoptosis in human lung cancer cell line A549

Background

Recently, the anti-tumor activity of N-myc downstream-regulated gene 2 (NDRG2) was shown decreased expression in clear cell renal cell carcinoma (CCRCC), but the role of the down-expression of NDRG2 has not been described.

Methods

The NDRG2 recombinant adenovirus plasmid was constructed. The proliferation rate and NDRG2 expression of cell infected with recombinant plasmid were mesured by MTT, Flow cytometry analysis and western blot.

Results

The CCRCC cell A-498 re-expressed NDRG2 when infected by NDRG2 recombinant adenovirus and significantly decreased the proliferation rate. Fluorescence activated cell sorter analysis showed that 25.00% of cells expressed NDRG2 were in S-phase compared to 40.67% of control cells, whereas 62.08% of cells expressed NDRG2 were in G1-phase compared to 54.39% of control cells (P < 0.05). In addition, there were much more apoptotic cells in NDRG2-expressing cells than in the controls (P < 0.05). Moreover, upregulation of NDRG2 protein was associated with a reduction in cyclin D1, cyclin E, whereas cyclinD2, cyclinD3 and cdk2 were not affected examined by western blot. Furthermore, we found that p53 could upregulate NDRG2 expression in A-498 cell.

Conclusions

We found that NDRG2 can inhibit the proliferation of the renal carcinoma cells and induce arrest at G1 phase. p53 can up-regulate the expression of NDRG2. Our results showed that NDRG2 may function as a tumor suppressor in CCRCC.     

Methylation-associated silencing of miR-9-1 promotes nasopharyngeal carcinoma progression and glycolysis via HK2

Characteristically, cancer cells metabolize glucose through aerobic glycolysis, known as the Warburg effect. Accumulating evidence suggest that during cancer formation, microRNAs (miRNAs) could regulate such metabolic reprogramming. In the present study, miR-9-1 was identified as significantly hypermethylated in nasopharyngeal carcinoma (NPC) cell lines and clinical tissues. Ectopic expression of miR-9-1 inhibited NPC cell growth and glycolytic metabolism, including reduced glycolysis, by reducing lactate production, glucose uptake, cellular glucose-6-phosphate levels, and ATP generation in vitro and tumor proliferation in vivo. HK2 (encoding hexokinase 2) was identified as a direct target of miR-9-1 using luciferase reporter assays and Western blotting. In NPC cells, hypermethylation regulates miR-9-1 expression and inhibits HK2 translation by directly targeting its 3' untranslated region. MiR-9-1 overexpression markedly reduced HK2 protein levels. Restoration of HK2 expression attenuated the inhibitory effect of miR-9-1 on NPC cell proliferation and glycolysis. Fluorescence in situ hybridization results indicated that miR-9-1 expression was an independent prognostic factor in NPC. Our findings revealed the role of the miR-9-1/HK2 axis in the metabolic reprogramming of NPC, providing a potential therapeutic strategy for NPC.     

siRNA-mediated down-regulation of survivin inhibits bladder cancer cell growth

Survivin is recognized as a general target in cancer therapy because of its selective overexpression in the majority of tumors. In bladder cancer (BCa), its expression correlates with tumor grade, recurrence risk and survival. In this study, we compared the therapeutic efficiency of two survivin specific small interfering RNA (siRNA) constructs, SVV284 and SVV094, to inhibit the growth of five human BCa cell lines (EJ28, 5637, J82, RT112, RT4). In a period between 24 to 72 h after siRNA SVV284 transfection, EJ28 and 5637 showed a significant reduction (up to 47%) of viability. For both cell lines cell cycle analysis and quantitation of apoptosis revealed both a specific G2/M arrest and an induction of apoptosis, as well as the occurrence of multinucleated cells. The cell lines EJ28, 5637 and J82 exhibited a prolonged duplication time up to 1.4-fold at 72 h after treatment. Furthermore, in these three cell lines the mRNA and protein expression quantified by real time RT-PCR and ELISA was reduced by at least 50% and up to 99%, respectively. However, RT112 and RT4 cells did not show an effective down-regulation of survivin expression. In comparison to siRNA SVV284, the treatment with siRNA SVV094 exhibited less inhibitory effects on cell growth and survivin expression in all BCa cell lines tested. In summary, the results suggest that the anti-survivin siRNA treatment might represent a suitable therapeutic approach to selectively inhibit growth of BCa cells in addition to commonly applied therapy schemes.     

Photodynamic-induced apoptosis of human nasopharyngeal carcinoma cells using Hypocrellins

It has been reported that novel photosensitizers Hypocrellin A and B, lipid soluble perylquinone derivatives of the genus Hypericum have a strong photodynamic effect on tumors and viruses. The molecular mechanisms of tumor cell death induction by Hypocrellin A and B are poorly understood. In this study, we have examined the photodynamic effects of Hypocrellin A and B compounds in poorly differentiated (CNE2) and moderately differentiated (TW0-1) human nasopharyngeal carcinoma (NPC) cells. Using these cell lines we investigated the role of the apoptotic pathway in photosensitized Hypocrellin A and B-mediated cell death. Tumor cells photoactivated with Hypocrellin A and B showed cell size shrinkage and an increase in the sub-diploid DNA content. A loss of membrane phospholipid asymmetry associated with apoptosis was induced by both tumor cell lines as evidenced by the externalization of phosphatidylserine (PS). A dose-dependent increase in caspases-3 protease activity inhibitable by the tetrapeptide inhibitor DEVD-CHO was also observed in both cell lines. Western blot analysis of poly (ADP-ribose) polymerase, a caspase substrate, showed the classical cleavage pattern (116 to 85 kDa) associated with apoptosis in Hypocrellin A and B-treated cell lysates. In addition, caspase inhibition blocked the externalization of membrane PS, indicating that the loss of membrane phospholipid asymmetry is a downstream event of caspases activation. These results demonstrate that tumor cell death induced by Hypocrellin A and B is mediated by caspase proteases. In conclusion, this study identifies both Hypocrellins (A and B) as potent and promising photosensitizers for the treatment of NPC.     

Phase II trial of a paclitaxel and carboplatin combination in Asian patients with metastatic nasopharyngeal carcinoma

Purpose: An earlier phase II trial of paclitaxel in patients with metastatic nasopharyngeal carcinoma (NPC) demonstrated a response rate of 22%. Hence we proceeded to study the combination of paclitaxel and carboplatin in these patients.Patients and methods: The 21-day regimen was as follows: i.v. paclitaxel 175 mg/m2 over three hours preceded by standard premedications, followed by i.v. carboplatin dosed at AUC of six infused over one hour. Only chemotherapy-naïve patients with histological diagnoses of undifferentiated carcinoma of the nasopharynx, systemic metastases and radiologically measurable lesions were eligible.Results: Thirty-two patients were accrued to this study. Twenty patients (62%) had at least two sites of metastasis. The main grade 3–4 toxicity was neutropenia (31%). Nine patients (28%) developed neutropenic sepsis, which caused the demise of one of them. Twenty-four patients (75%) responded to treatment, with one (3%) attaining a complete response. The median time to progression of disease was seven months and the median survival was 12 months. At one year, 52% of the patients were alive.Conclusions: The combination of paclitaxel and carboplatin is an active regimen in NPC. Its convenience of administration and good tolerability make it an attractive alternative regimen to consider for patients with metastatic disease.     

慢病毒介导shRNA特异性沉默livin基因促进SPC-A1细胞凋亡

目的：建立慢病毒介导的livin基因沉默系统,探讨其对肺癌细胞凋亡的影响。方法：Livin shRNA慢病毒感染肺腺癌细胞株SPCA1沉默livin基因表达。应用PI染色经荧光镜下观察SPCA1细胞凋亡形态,流式细胞术检测SPCA1细胞凋亡率及亚二倍体峰形成,Realtime PCR及Western blotting方法检测livin和caspase 3表达的改变。结果：livin基因在肺腺癌细胞株SPCA1中持续高表达。经慢病毒介导shRNA使livin基因表达沉默后,镜下可见肺腺癌细胞出现典型凋亡形态特征,流式细胞术检测出现亚二倍体峰,细胞凋亡率较空白对照及阴性病毒对照细胞明显增加（8.21％ vs 0.08％, 0.13％;P<0.05）,RTPCR及Western blotting 检测结果显示,caspase 3 mRNA表达无改变,但cleavedcaspase 3蛋白表达上调。结论：慢病毒载体介导的shRNA能抑制肺腺癌细胞株SPCA1中livin基因的表达,从而促进SPCA1细胞凋亡。     

A new anticancer compound, oblongifolin C, inhibits tumor growth and promotes apoptosis in HeLa cells through Bax activation

Oblongifolin C (OC) was identified as a potent apoptosis inducer from an herbal plant, Garcinia yunnanensis, during our previous bioassay-guided drug screening. In this study, we investigated the signaling pathways through which OC activated apoptosis in HeLa cells. We also compared the IC(50) values of OC with that of etoposide, paclitaxel and vinblastine in multiple cancer cell lines including HER2 and P-glycoprotein overexpressing cells. In addition, the in vivo antitumor effect of OC was studied in nude mice model. Our results showed that OC induced a caspase-dependent apoptosis by triggering a series of events in HeLa cells including Bax translocation, cytochrome c release, caspase-3 activation, chromosome fragmentation followed by caspase-8 activation, Bid cleavage and eventually cell death. Addition of a pan-caspase inhibitor or overexpression of an anti-apoptotic protein, Bcl-xL, prevented OC-induced cell death. Moreover, OC exhibited a wide anticancer spectrum in multiple cancer cell lines with comparable IC(50) values, regardless of the expression levels of HER2 and P-glycoprotein. In contrast, the IC(50) values of three clinical anticancer drugs, etoposide, paclitaxel and vinblastine were significantly elevated in HER2 and/or P-glycoprotein overexpressing cells. Furthermore, OC showed a similar antitumor effect but lower general toxicity than etoposide against xenografted human tumors in nude mice model. All these data suggested that OC is a promising apoptosis inducer with the potential to be developed into a clinical anticancer drug.