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。     

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.     

Preferential chemosensitization of PTEN-mutated prostate cells by silencing the Akt kinase

BACKGROUND: In prostate cancer, mutations of the phosphatase PTEN can activate the kinase cascade PI3K/Akt/mTOR which induces drug resistance. METHODS: Chemosensitization by siRNA targeting Akt was studied in HEK293 cells forced to express CA-Akt or kinase-dead DN-Akt. To decrease drug resistance, Akt was silenced with siRNA in human prostate DU-145 cell line expressing the normal PTEN or in LNCaP and PC3 cell lines expressing mutated-PTEN. Taxol was used for the chemosensitization studies. RESULTS: Silencing Akt in the drug-resistant CA-Akt cells efficiently sensitized cells to antitubule agents, whereas silencing drug-responsive DN-Akt cells did not. Only minor effects were obtained in wild-type HEK293 cells. Potentiation by siRNA of taxol cytotoxicity was significantly greater in mutated-PTEN cells than in prostate cells expressing wild-type PTEN. The apoptotic program induced by taxol was preferentially potentiated by Akt siRNA in PTEN-mutated cell lines as regards the DU-145 cell line. CONCLUSIONS: Silencing Akt in PTEN-mutated prostate cancer cells enhances the antitumor effects of taxol. No siRNA chemosensitization was obtained in prostate cells with wild type PTEN.     

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。     

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.     

米非司酮增加宫颈癌Caski细胞对顺铂敏感性的研究

目的：探讨米非司酮作用于人宫颈鳞癌Caski细胞后对顺铂敏感性的影响和机制。为临床应用米非司酮治疗宫颈鳞癌提供实验依据。方法：体外培养人宫颈鳞癌Caski细胞，分别或联合应用不同浓度的米非司酮、顺铂处理Caski细胞，采用四甲基偶氮唑蓝比色法测定米非司酮对Caski细胞增殖活性的作用及其对顺铂敏感性的影响；流式细胞术观察各组细胞凋亡率，并分析细胞周期的变化；异硫氰酸荧光素（FITC）荧光标记流式细胞术（FCM）法测定米非司酮对Caski细胞HPV—E6，p53，Bcl-2，Bax蛋白的表达变化。结果：四甲基偶氮唑蓝比色法结果显示，1．25、2．5mg／L的米非司酮对Caski细胞无显著的抑制作用，其与顺铂合用时能增强顺铂对Caski细胞增殖抑制作用。流式细胞术结果显示，米非司酮（1．25mg／L）对Caski细胞无明显的诱导凋亡作用，但能促进顺铂（1．0、2．0、4．0mg／L）诱导其凋亡。FITC荧光标记FCM法结果显示，米非司酮作用于Caski细胞后，HPV—E6、Bcl-2蛋白表达下调，p53、Bax蛋白表达上调，呈浓度依赖方式。结论：米非司酮能增强顺铂对Caski细胞的增殖抑制和诱导凋亡并对Caski细胞有增殖抑制和化疗增敏作用，与下调HPV16-E6、Bcl-2蛋白表达，上调p53、Bax蛋白表达有关。     

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.     

Treatment of advanced myelodysplastic syndrome with a regimen including recombinant human granulocyte colony-stimulating factor preceding allogeneic bone marrow transplantation

We treated 13 patients with morphologically advanced myelodysplastic syndrome using cytosine arabinoside and total body irradiation, followed by allogeneic marrow transplantation from HLA-identical sibling donors. Granulocyte colony-stimulating factor (G-CSF) was added to the preparative regimen to selectively increase chemosensitivity of leukaemic cells and to improve transplant outcome. No regimen-related deaths occurred, and no side-effects related to the addition of G-CSF were observed except for transient mild bone pain. At a median follow-up time of 39 months the projected 5-year disease-free survival and 5-year overall survival were 67.7% and 75.5%, respectively, with only one case showing cytogenetic relapse. The preparative regimen including G-CSF is feasible, and preliminary results seem to be encouraging. However, a larger trial is clearly warranted to evaluate its efficacy.     

siRNA沉默Livin基因对乳腺癌MCF-7细胞化学治疗增敏作用的研究

目的：观察小干扰RNA（siRNA）沉默Livin基因对人乳腺癌细胞MCF‐7细胞生物学影响及siRNA沉默MCF‐7细胞Livin基因对4种化学治疗药物的增敏作用。方法 Lipofectamine 2000脂质体转染法转染MCF‐7。分组：空白组（无转染）、脂质体组、反义组、错义组、联合组。MTT法测定氟尿嘧啶（5‐FU）、表柔比星（EPI）、多西紫杉醇（DXT）、吉西他滨（GEM）单药（单药组）对乳腺癌细胞MCF‐7增殖的抑制作用。免疫组织化学检测Livin蛋白在MCF‐7细胞中的表达及转染联合化学治疗药物对Livin蛋白的表达变化。实时荧光定量PCR（RT‐PCR）检测转染Livin siRNA后乳腺癌MCF‐7细胞的Livin基因表达变化。同时利用Annexin‐V检测乳腺癌细胞的凋亡及siRNA Livin联合5‐FU、EPI、DXT、GEM 诱导乳腺癌细胞凋亡的影响。结果 Livin在MCF‐7细胞中高表达,4种化学治疗药物对 Livin表达无明显影响,转染Livin基因48、72 h后联合4种药物后能明显下调Livin蛋白表达,差异有统计学意义（P＜0．05）。5‐FU、EPI、DXT、GEM治疗乳腺癌MCF‐7细胞48、72 h均能明显的引起细胞的凋亡,且呈剂量依赖性。转染Livin基因48 h联合4种药物后乳腺癌MCF‐7细胞的凋亡率明显高于单药处理的细胞,差异有统计学意义（P＜0．01）。结论 siRNA沉默Livin基因能促进由化学治疗药物5‐FU、EPI、DXT、GEM引起的细胞凋亡,具有化学治疗增敏作用。