Decitabine reactivated pathways in platinum resistant ovarian cancer

Combination therapy with decitabine, a DNMTi and carboplatin resensitized chemoresistant ovarian cancer (OC) to platinum inducing promising clinical activity. We investigated gene-expression profiles in tumor biopsies to identify decitabine-reactivated pathways associated with clinical response. Gene-expression profiling was performed using RNA from paired tumor biopsies before and 8 days after decitabine from 17 patients with platinum resistant OC. Bioinformatic analysis included unsupervised hierarchical-clustering, pathway and GSEA distinguishing profiles of “responders” (progression-free survival, PFS>6months) and “non-responders” (PFS<6months). Functional validation of selected results was performed in OC cells/tumors. Pre-treatment tumors from responders expressed genes associated with enhanced glycosphingolipid biosynthesis, translational misregulation, decreased ABC transporter expression, TGF-β signaling, and numerous metabolic pathways. Analysis of post-treatment biopsies from responders revealed overexpression of genes associated with reduced Hedgehog pathway signaling, reduced DNA repair/replication, and cancer-associated metabolism. GO and GSEA analyses revealed upregulation of genes associated with glycosaminoglycan binding, cell-matrix adhesion, and cell-substrate adhesion. Computational findings were substantiated by experimental validation of expression of key genes involved in two critical pathways affected by decitabine (TGF-β and Hh). Gene-expression profiling identified specific pathways altered by decitabine and associated with platinum-resensitization and clinical benefit in OC. Our data could influence patient stratification for future studies using epigenetic therapies.     

中药活性成分 — 姜黄素抗乳腺癌的基础研究新进展

乳腺癌已成为中国女性最常罹患的恶性肿瘤,肿瘤绿色治疗已成为趋势,所以,研发“增效减毒”的抑制乳腺癌细胞增殖的药物对乳腺癌治疗具有十分重要的意义。姜黄素作为中草药姜黄根茎的活性提取物,因其有效抑制乳腺肿瘤细胞增殖,改善患者预后,有效减轻乳腺癌化疗后反应,正被越来越多的研究人员和临床医生青睐,成为研究的焦点。该文就姜黄素抑制乳腺癌增殖的分子机制,姜黄素剂型和载药系统,姜黄素联合放疗和化疗增效减毒的体内外实验研究进展进行综述。     

Chemosensitization of Solid Tumors by Inhibition of Bcl-xL Expression Using DNAzyme

DNAzymes are a novel class of gene suppressors that selectively bind to an RNA substrate by Watson-Crick base pairing and cleave phosphodiester bonds. To explore the potential for therapeutic use of catalytic DNA molecules, active DNAzymes targeting the bcl-xL gene were generated through a multiplex in vitro selection. The DNAzyme-mediated down-regulation of the bcl-xL expression was demonstrated in various cancer cell lines by Western blots. Treatment of the cells with the active DNAzyme led to increases in percentage of apoptotic cells and cytochrome c release from mitochondria, a hall marker of apoptosis. When combined with chemotherapeutics such as Taxol, the DNAzyme significantly sensitised a panel of cancer cells to apoptosis as measured by cell survival assay. In Taxol-resistant cells, down-regulation of bcl-xL expression by the DNAzyme reversed the chemo-resistant phenotype of the cancer cells. In a xenograft mouse model, the DNAzyme was delivered into the tumors via an ALZET osmotic pump and shown to chemosensitize PC3 tumor when treating with Taxol. The results from the present study demonstrate that bcl-xL DNAzyme treatment facilitates apoptosis in solid tumors and suggest the potential use of bcl-xL DNAzyme in combination with chemotherapeutics for cancer therapy.     

Oligomycin A enhances apoptotic effect of TRAIL through CHOP‐mediated death receptor 5 expression

Development of resistance to TNF‐related apoptosis‐inducing ligand (TRAIL) in tumor cells is one of the important problems in cancer treatment. Despite the previous report demonstrating that oligomycin suppressed TNF‐induced apoptosis, in our screening of small molecules enhancing cancer cell death to TRAIL, oligomycin A (OMA) was found to enhance TRAIL‐induced apoptosis in HeLa cells. CCAAT/enhancer‐binding protein homologous protein (CHOP) was found to directly bind to death receptor 5 (DR5) promoter through endoplasmic reticulum stress (ER‐stress) signaling and sensitize the cells to TRAIL. Among ER‐stress associated proteins, OMA triggered the inositol‐requiring enzyme 1 (IRE1) signaling pathway, leading to X‐binding protein 1 (XBP1) splicing, CHOP expression and DR5 upregulation. In contrast, small‐interfering RNA (siRNA) of CHOP reduced the number of apoptotic cells in response to the co‐treatment of TRAIL and OMA. Collectively, our data suggest that OMA enhances apoptotic death of cervical cancer cells to TRAIL through upregulation of CHOP‐mediated DR5 expression following ER‐stress. © 2011 Wiley Periodicals, Inc.     

康莱特增加肺癌细胞对健择敏感性的实验研究

目的：研究康莱特联合化疗药物健择抑制人肺腺癌细胞95D生长的作用,同时寻找康莱特联合化疗药物健择作用的最佳时机。方法：采用MTT比色法进行检测。结果：康莱特单药对人肺腺癌95D的生长有抑制作用,联合健择的抑制率高于单药组;康莱特先于健择加入对95D的抑制最强。结论：康莱特体外对肺癌细胞有抗肿瘤和化疗增敏作用;康莱特先于健择加入对95D的抑制最强。     

康莱特联合化疗药物增敏的最佳时机的实验研究

目的:寻找康莱特联合化疗药物健择和顺铂的最佳时机。方法:采用MTT比色的方法。结果:康莱特对人肺腺癌95D的生长有抑制作用和化疗增敏作用;康莱特先于健择,顺铂加入对95D的抑制最强。结论:康莱特先于健择或顺铂加入优于两药同时加入。     

Induction of apoptosis and chemosensitization of mesothelioma cells by Bcl-2 and Bcl-xL antisense treatment

Our study was designed to investigate the role of the anti-apoptotic proteins Bcl-2 and Bcl-xL in the chemoresistance of cells derived from malignant pleural mesothelioma. First, we determined the basal expression levels of Bcl-2 and Bcl-xL in mesothelioma cells and examined the effect of their downregulation by antisense oligonucleotides. Bcl-xL mRNA and protein could be readily detected in mesothelioma cell lines, whereas only low levels of Bcl-2 mRNA and protein were found. Preferential downregulation of either Bcl-xL alone or of Bcl-xL and Bcl-2 simultaneously was achieved by treatment with antisense oligonucleotides 4259 and 4625, respectively, whereas the expression of other apoptosis-relevant genes remained unaffected. Treatment with oligonucleotides 4259 or 4625 lowered the apoptosis threshold in ZL34 mesothelioma cells, as indicated by an increase in cell death accompanied by increased caspase-3-like activity, a decrease of the mitochondrial transmembrane potential and the cleavage of procaspase-7 and ICAD. In addition to the direct induction of apoptosis, antisense treatment sensitized ZL34 cells to the cytostatic effect of cisplatin and gemcitabine, with the combination of 4625 and cisplatin being the most effective. Our results demonstrate that Bcl-2 and Bcl-xL antisense treatment facilitates apoptosis in mesothelioma cells and suggest the use of Bcl-2/Bcl-xL bispecific antisense treatment in combination with cisplatin or gemcitabine for therapy of malignant pleural mesothelioma.     

γ-氨基丁酸抑制结直肠癌细胞增殖及其对化疗的增敏作用

目的:通过体内、体外实验,探讨γ-氨基丁酸(γ-aminobutyric acid,GABA)对结直肠癌SW480、HCT116细胞的抑制作用及其与化疗联用的增敏作用.方法:采用CCK-8方法分析GABA及其与抗癌药5-氟尿嘧啶(5-fluorouracil,5-ru)或奥沙利铂(Oxaliplatin,OXA)联用对结直肠癌SW480、HCT116细胞增殖的影响,流式细胞术分析GABA对SW480、HCT116细胞周期的影响.通过裸鼠成瘤实验观察移植瘤质量和体积,免疫组化法检测裸鼠肿瘤组织Ki67蛋白的表达,TUNEL染色观察裸鼠结直肠癌细胞的凋亡,体内实验研究GABA与OXA联用对肿瘤细胞生长的影响.结果:100 μmol/L GABA可显著抑制结直肠癌SW480、HCT116细胞的增殖,其抑制率分别为(37.38±2.62)％、(15.54±1.33)％,GABA浓度增加至200 μmol/L时,其抑制作用未见明显增强.GABA使SW480、HCT116细胞S期数量分别减少11.8％及10.7％.GABA与5-FU或OXA联用组对SW480细胞增殖抑制率高于5-FU或OXA组[(72.76±1.07)％ vs (63.82±3.29)％或(65.60±1.19)％ vs (57.09±1.25)％;q=4.079或4.128,P＜0.05],对HCT116细胞增殖抑制率也高于单用5-FU及OXA组[(79.53±1.12)％ vs(69.71±0.09)％或(73.19±0.07)％ vs(64.65 ±1.99)％;g=4.569或4.561,P＜O.05].实验结束时,GABA与OXA联用组小鼠移植瘤质量、体积显著低于对照组和OXA组[(0.20±0.016) vs (0.42±0.039)、(0.36±0.030)g和(250±27)vs(780±60)、(520±46) mm3,均P＜0.01];抑制Ki67蛋白在肿瘤组织的表达、促进肿瘤组织细胞的凋亡.结论:GABA对结直肠癌细胞增殖具有较强的抑制作用,与5-FU或OXA联用可增强化疗效果.     

Influence of Tamoxifen or the combination of Tamoxifen and Cisplatin on the growth of human lung adenocarcinoma A549 cells

The experiment aims to investigate the influence of Tamoxifen and the combination of Tamoxifen and Cisplatin （DDP） on the growth of human lung adenocarcinoma A549 cells. Methods： We treated human lung adenocarcinoma A549 cells with different concentrations of Tamoxifen, DDP and combination of DDP and Tamoxifen with non-toxicity for 72 h. Then we calculated the inhibition rate through MTT approach and detected the apoptosis rate by flow cytometry. The statistical analysis was performed with SPSS 13.0 software and statistical differences were determined by one-way ANOVA. The data were expressed as the mean ＋ standard deviation and all experiments were performed in three times. The value of P 〈 0.05 was considered to indicate a statistically significant difference. Results： 1. The inhibition rates of Tamoxifen with 2.5 pmol/L, 5 tJmol/L, 10 μmol/L, and 20 μmol/L on the growth of the A549 cells were 18.7%, 25.8%, 54% and 98.8%, respectively （P = 0.000）. Tamoxifen with concentration of 1 μmol/L has no obvious cytoxicity on the A549 cells （P 〉 0.05）. 2. As the increase concentration of Tarnoxifen, the S stage and G2/M of the A549 cells decreased while the G0/G1 increased. The apoptosis rate of Tamoxifen with 0 μmol/L, 0.1 μmol/L, 1 μmol/L and 10 μmol/L on the A549 cells were 6.51%, 8.91%, 17.97% and 42.7%, respectively. 3. The inhibition rates of combination of Tamoxifen with 1 μmol/L and DDP with 1.25 μg/mL, 2.5 μg/mL, 5 μg/mL, 10 μg/mL and 20 μg/mL on the A549 cells were 40.4%, 54.4%, 72.9%, 86.1% and 92.4%, respectively （P 〈 0.05）. Conclusion： Tamoxifen can inhibit the proliferation of human lung adenocarcinoma A549 cells and induce the apoptosis of the A549 cells. The combination of Tamoxifen with non-toxicity and DDP can improve the sensitivity of chemotherapy on the A549 cells.     

Reversal of multidrug resistance in murine fibrosarcoma cells by thioxanthene flupentixol

Summary The purpose of this study was to identify calcium channel and calmodulin antagonists effective in increasing the cytotoxic effects of several chemotherapeutic drugs against UV-2237 murine fibrosarcoma MDR cells. Among 8 compounds tested at nontoxic concentrations, flupentixol, a piperazine-substituted thioxanthene, was the most potent in enhancing the cytotoxicity of anticancer drugs commonly associated with the multidrug resistant (MDR) phenotype, such as Adriamycin, actinomycin D, vinblastine, and vincristine, but not 5-fluorouracil, a drug usually unaffected by MDR. The chemosensitizing effects of flupentixol were produced by increasing intracellular drug accumulation via a mechanism unrelated to the binding of the plasma membrane P-glycoprotein.