Erythropoietin inhibits apoptosis induced by photodynamic therapy in ovarian cancer cells

Recombinant human erythropoietin is widely used to treat anemia associated with cancer and with the myelosuppressive effects of chemotherapy, particularly platinum-based regimens. Erythropoietin is the principal regulator of erythroid cell proliferation, differentiation, and apoptosis. Recently, the antiapoptotic and proliferative effects of erythropoietin on nonhematopoietic cells were also established. We now show the effect of erythropoietin treatment on the response of A2780 and SKOV3 ovarian carcinoma cell lines to photodynamic therapy (PDT) using hypericin. SKOV3 exhibited an increased resistance to hypericin when cells were treated with erythropoietin. This resistance was reversed by treatment of SKOV3 cells with the specific Janus kinase 2 kinase inhibitor AG490 or the tyrosine kinase inhibitor genistein. These results support a role for the specific erythropoietin-induced Janus kinase 2/STAT signal transduction pathway in PDT resistance. Evidence of erythropoietin signaling was obtained by the demonstration of Akt phosphorylation in both A2780 and SKOV3 cells. Erythropoietin-treated SKOV3 cells exhibited decreased apoptosis induced by hypericin, an effect that was blocked by the phosphoinositide 3-kinase/Akt inhibitor wortmannin. These results may have important implications for ovarian cancer patients undergoing PDT and receiving erythropoietin.     

Smoothened antagonists reverse taxane resistance in ovarian cancer

The hedgehog pathway has been implicated in the formation and maintenance of a variety of malignancies, including ovarian cancer; however, it is unknown whether hedgehog signaling is involved in ovarian cancer chemoresistance. The goal of this study was to determine the effects of antagonizing the hedgehog receptor, Smoothened (Smo), on chemotherapy response in ovarian cancer. Expression of hedgehog pathway members was assessed in three pairs of parental and chemotherapy-resistant ovarian cancer cell lines (A2780ip2/A2780cp20, SKOV3ip1/SKOV3TRip2, HeyA8/HeyA8MDR) using quantitative PCR and Western blot analysis. Cell lines were exposed to increasing concentrations of two different Smo antagonists (cyclopamine, LDE225) alone and in combination with carboplatin or paclitaxel. Selective knockdown of Smo, Gli1, or Gli2 was achieved using siRNA constructs. Cell viability was assessed by MTT assay. A2780cp20 and SKOV3TRip2 orthotopic xenografts were treated with vehicle, LDE225, paclitaxel, or combination therapy. Chemoresistant cell lines showed higher expression (>2-fold, P < 0.05) of hedgehog signaling components compared with their respective parental lines. Smo antagonists sensitized chemotherapy-resistant cell lines to paclitaxel, but not to carboplatin. LDE225 treatment also increased sensitivity of ALDH-positive cells to paclitaxel. A2780cp20 and SKOV3TRip2 xenografts treated with combined LDE225 and paclitaxel had significantly less tumor burden than those treated with vehicle or either agent alone. Increased taxane sensitivity seems to be mediated by a decrease in P-glycoprotein (MDR1) expression. Selective knockdown of Smo, Gli1, or Gli2 all increased taxane sensitivity. Smo antagonists reverse taxane resistance in chemoresistant ovarian cancer models, suggesting combined anti-hedgehog and chemotherapies could provide a useful therapeutic strategy for ovarian cancer.     

1,1-Bis(3'-indolyl)-1-(p-substituted phenyl)methanes inhibit ovarian cancer cell growth through peroxisome proliferator-activated receptor-dependent and independent pathways

1,1-Bis(3'-indolyl)-1-(p-t-butylphenyl)methane (DIM-C-pPhtBu) is a peroxisome proliferator-activated receptor gamma (PPARgamma) agonist, and treatment of SKOV3 ovarian cancer cells with this compound (5 micromol/L) inhibits cell proliferation, whereas up to 15 micromol/L rosiglitazone had no effect on cell growth. DIM-C-pPhtBu also inhibits G0-G1 to S phase cell cycle progression and this is linked, in part, to PPARgamma-dependent induction of the cyclin-dependent kinase inhibitor p21. DIM-C-pPhtBu induces PPARgamma-independent down-regulation of cyclin D1 and we therefore further investigated activation of receptor-independent pathways. DIM-C-pPhtBu also induced apoptosis in SKOV3 cells and this was related to induction of glucose-related protein 78, which is typically up-regulated as part of the unfolded protein response during endoplasmic reticulum (ER) stress. Activation of ER stress was also observed in other ovarian cancer cell lines treated with DIM-C-pPhtBu. In addition, DIM-C-pPhtBu induced CCAAT/enhancer binding protein homologous protein through both ER stress and c-jun NH2-terminal kinase-dependent pathways, and CCAAT/enhancer binding protein homologous protein activated death receptor 5 and the extrinsic pathway of apoptosis. These results show that DIM-C-pPhtBu inhibits growth and induces apoptosis in ovarian cancer cells through both PPARgamma-dependent and PPARgamma-independent pathways, and this complex mechanism of action will be advantageous for future clinical development of these compounds for treatment of ovarian cancer.     

Role of TLR4 for paclitaxel chemotherapy in human epithelial ovarian cancer cells

Background  Paclitaxel has been reported to be a ligand to Toll like receptor 4 (TLR4). Myeloid differentiation factor 88(MyD88) was described as a myeloid differentiation primary response gene. TLR4 signalling owns two pathways: MyD88-dependent and MyD88-independent pathways. XIAP is a key member of the inhibitor of apoptosis protein family. Akt is a major downstream target of growth factor receptor tyrosine kinases, which negatively regulates apoptotic pathways through phosphorylation (pAkt). The aim of the present study is to investigate the role of TLR4 in paclitaxel resistance of ovarian cancer cells.
Materials and methods  We reconstructed the RNA interference expression vector, pGenesil-1-U6 specifically targeting TLR4 mRNA, which was stable transfected into the human ovarian cancer cell line SKOV3 (MyD88-positive expression) and A2780 (MyD88-negative expression). Cell proliferation, cell cycle distribution and cell apoptosis were assessed in the cells transfected with scramble control shRNA (SKOV3/shControl, A2780/shControl) and TLR4 shRNA (SKOV3/shTLR4, A2780/shTLR4) to explore the possible functions of TLR4 in ovarian cancer cells growth. The expression of TLR4, MyD88, XIAP, Akt and pAkt was analysed by Western blot analysis.
Results  A knockdown of TLR4 levels down-regulated the expression of XIAP and pAkt. And it restored the inhibitory effect of paclitaxel on cell proliferation and impeding cell cycle progression in SKOV3 cells.
Conclusions  It suggests that TLR4 negatively regulates paclitaxel chemotherapy and MyD88 is an essential downstream factor to TLR4 signalling for this resistance. Knockdown of TLR4 induces paclitaxel chemosensitivity which might depress the Akt pathway. The TLR4-MyD88 signalling represents an important source to promote tumour growth.     

MiR-139-5p通过靶向NFAT抑制卵巢癌SKOV3细胞的生长、集落形成、侵袭和迁移

目的:探究miR-139-5p对卵巢癌SKOV3细胞的生长、集落形成、侵袭能力以及迁移能力的影响及其机制。方法:采用qRT-PCR检测卵巢癌患者癌组织和卵巢癌细胞SKOV3中miR-139-5p表达情况。MiR-139-5p mimic转染SKOV3细胞,WST比色实验、集落形成实验和Transwell实验分别检测细胞的活性、集落形成、侵袭和迁移能力。采用TargetScan在线软件筛选miR-139-5p的潜在靶基因NFAT,并进一步验证。结果:MiR-139-5p在卵巢癌组织和SKOV3细胞中表达异常降低。MiR-139-5p过表达显著抑制SKOV3细胞的生长、集落形成、迁移及侵袭能力。NFAT是miR-139-5p的靶基因。过表达NFAT能逆转miR-139-5p过表达对SKOV3细胞集落形成、侵袭能力以及迁移能力与侵袭的抑制作用。结论:MiR-139-5p通过抑制靶基因NFAT来抑制卵巢癌SKOV3细胞的生长、集落形成、侵袭和迁移能力。     

X-linked inhibitor of apoptosis protein inhibition induces apoptosis and enhances chemotherapy sensitivity in human prostate cancer cells

Androgen-insensitive prostate cancer cells are highly resistant to several chemotherapeutic drugs and are characterized by the appearance of apoptosis-resistant cells. In this study, we identified the critical role of X-linked inhibitor of apoptosis protein (XIAP), a potent antiapoptotic factor, in conferring chemotherapy resistance in an androgen-insensitive DU145 human prostate cancer cell line. Results reveal that DU145 cells were highly resistant to cisplatin, but this resistance was overridden when the cells were treated for a prolonged time (>96 hours) with cisplatin (IC(50) = 27.5 to 35.5 micromol/L). A decrease in levels of XIAP and Akt/phospho-Akt and an increase in caspase-3 activity were identified to be key factors in cisplatin sensitivity (40% to 55% decrease in cell viability) at later time points. In contrast, tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) treatment caused a 40% to 50% decrease in cell viability within 6 hours (IC(50) = 135 to 145 ng/mL). However, increasing concentrations or prolonged treatment with TRAIL did not change drug potency. A significant increase in caspase-3 activity was observed with TRAIL treatment with no apparent change in XIAP levels. Specific inhibition of XIAP expression using an antisense XIAP phosphorodiamidate morpholino oligomer induced apoptosis and increased caspase-3 activity. Combination of cisplatin with XIAP antisense potentiated cisplatin sensitivity by decreasing the IC(50) from >200 micromol/L with cisplatin alone to 9 to 20 micromol/L and decreasing incubation time required for activity from 96 to 24 hours. Similarly, TRAIL in combination with XIAP antisense phosphorodiamidate morpholino oligomer enhanced TRAIL potency by 12- to 13-fold. In conclusion, abrogation of XIAP expression is essential for therapeutic apoptosis and enhanced chemotherapy sensitization in androgen-refractory prostate cancer cells.     

Potent activation of mitochondria-mediated apoptosis and arrest in S and M phases of cancer cells by a broccoli sprout extract

We have previously shown that broccoli sprouts are a rich source of chemopreventive isothiocyanates, which potently induce carcinogen-detoxifying enzymes and inhibit the development of mammary and skin tumors in rodents. However, the principal isothiocyanate present in broccoli sprout extracts, sulforaphane, not only induces carcinogen-detoxifying enzymes but also activates apoptosis and blocks cell cycle progression. In this article, we show that an aqueous extract of broccoli sprouts potently inhibits the growth of human bladder carcinoma cells in culture and that this inhibition is almost exclusively due to the isothiocyanates. Isothiocyanates are present in broccoli sprouts as their glucosinolate precursors and blocking their conversion to isothiocyanates abolishes the antiproliferative activity of the extract. Moreover, the potency of isothiocyanates in the extract in inhibiting cancer cell growth was almost identical to that of synthetic sulforaphane, as judged by their IC50 values (6.6 versus 6.8 micromol/L), suggesting that other isothiocyanates in the extract may be biologically similar to sulforaphane and that nonisothiocyanate substances in the extract may not interfere with the antiproliferative activity of the isothiocyanates. Further study showed that the isothiocyanate extract of broccoli sprouts activated the mitochondria-mediated apoptosis pathway and halted cells in S and M phases. Cell cycle arrest was associated with down-regulation of Cdc25C and disruption of mitotic spindles. These data show that broccoli sprout isothiocyanate extract is a highly promising substance for cancer prevention/treatment and that its antiproliferative activity is exclusively derived from isothiocyanates.     

茶多酚联合顺铂对人卵巢癌细胞SKOV3生长的影响及机制

目的观察茶多酚(TP)、顺铂(DDP)及二者联合对人卵巢癌细胞SKOV3增殖及凋亡的影响,初步探讨二者联合对SKOV3细胞生长影响的机制。方法人卵巢癌细胞SKOV3经低毒剂量TP、DDP单独或联合作用后,MTT法检测细胞增殖情况,DAPI核染色法荧光显微镜观察细胞凋亡形态变化,AnnexinV-FITC双染流式细胞术分析细胞凋亡,Westernblot方法检测细胞中Akt及p-Akt的表达。结果低毒剂量TP单药组、DDP单药组与联合用药组对细胞的增殖抑制率分别为(11.47±2.07)%、(32.26±4.85)%、(52.62±3.23)%,联合用药组的细胞增殖抑制率明显高于DDP单药组,差异有统计学意义(P=0.000);荧光显微镜下可见低毒剂量TP单药组的细胞核形态及染色与阴性对照组无明显差异,联合用药组细胞核比DDP单药组着色更重,核浓缩、核碎裂现象更加明显,呈现典型的细胞凋亡征象;低毒剂量的TP对细胞的凋亡无明显影响,联合用药组的凋亡率明显高于DDP单药组,差异有统计学意义(P=0.000);各用药组细胞中总的Akt蛋白表达无明显变化,p-Akt蛋白表达降低,其中联合用药组细胞中p-Akt蛋白表达降低最明显,与对照组及单药组比较,差异均有统计学意义(P<0.001)。结论 TP与DDP联合后可显著增强DDP的抑制细胞增殖、促细胞凋亡效应,可能是通过抑制Akt蛋白的磷酸化来实现的。     

Efficient inhibition of ovarian cancer by truncation mutant of FILIP1L gene delivered by novel biodegradable cationic heparin-polyethyleneimine nanogels

Filamin A interacting protein 1-like (FILIP1L), which was reported to be consistently absent in ovarian cancer cell lines, has been identified to hold therapeutic potential for inhibiting tumor growth, and its COOH-terminal truncation mutant (FILIP1LΔC103) was found to be more potent than the wild-type. The use of polymeric nanoparticles to deliver functional gene intraperitoneally holds much promise as an effective therapy for ovarian cancer. In this study, a recombinant plasmid expressing FILIP1LΔC103 (FILIP1LΔC103-p) was constructed, and biodegradable cationic heparin-polyethyleneimine (HPEI) nanogels were prepared to deliver FILIP1LΔC103-p into human ovarian cancer SKOV3 cells. The expression of FILIP1LΔC103 in vitro and in vivo was determined using RT-PCR and western blot analysis. Moreover, a SKOV3 intraperitoneal ovarian carcinomatosis model was established to investigate the antitumor activity of HPEI+FILIP1LΔC103-p complexes in nude mice. Tumor weights were evaluated during the treatment course. Cell proliferation and apoptosis were evaluated by Ki-67 immunochemical staining and TUNEL assay, respectively, and the antiangiogenic effect of FILIP1LΔC103-p was assessed by CD31 immunochemical staining and alginate-encapsulated tumor cell assay. FILIP1LΔC103-p could be efficiently transfected into SKOV3 cells by HPEI nanogels. Intraperitoneal administration of HPEI+FILIP1LΔC103-p complexes led to effective growth inhibition of ovarian cancer, in which tumor weight decreased by almost 72% in the treatment group compared with that in the empty-vector control group. Meanwhile, decreased cell proliferation, increased tumor cell apoptosis, and reduction in angiogenesis were observed in the HPEI+FILIP1LΔC103-p group compared with those in the control groups. These results indicated that HPEI nanogels delivering FILIP1LΔC103-p might be of value in the treatment against human ovarian cancer.     

Growth inhibitory effects of celecoxib in human umbilical vein endothelial cells are mediated through G1 arrest via multiple signaling mechanisms

Evidence suggests that the angiogenic endothelium represents an important target through which celecoxib mediates in vivo antitumor effects. Nevertheless, the pharmacologic basis for celecoxib-caused growth inhibition in endothelial cells in vitro remains to be defined. Previously, we showed that celecoxib-induced apoptosis in PC-3 prostate cancer cells was mediated in part through the inhibition of 3-phosphoinositide-dependent kinase-1/Akt signaling. Our present findings show that celecoxib inhibits the growth of human umbilical vein endothelial cells (HUVEC) with pharmacologic profiles reminiscent of those of PC-3 cells. The underlying antiproliferative mechanism, however, may differ between these two cell types considering differences in the functional status of many tumor suppressors, including PTEN, p53, and retinoblastoma, all of which play integral roles in regulating cell cycle progression and survival. From a mechanistic perspective, the genomic integrity of the HUVEC system presents a vastly different intracellular context to examine how celecoxib acts to induce growth inhibition. Here, we obtain evidence that the antiproliferative effects of celecoxib and its close, cyclooxygenase-2-inactive analogue 4-[5-(2,5-dimethylphenyl)-3(trifluoromethyl)-1H-pyrazol-1-yl]benzenesulfonamide (DMC) in HUVECs at pharmacologically attainable concentrations (10-20 micromol/L) are attributable to the inhibition of phosphoinositide-dependent kinase-1/Akt signaling and cyclin-dependent kinase. Especially, celecoxib- and DMC-mediated G1 arrest is associated with attenuated retinoblastoma phosphorylation through the inhibition of multiple cyclin-dependent kinases (IC50, 10-35 micromol/L). Moreover, both celecoxib and DMC reduce neovascularization in the chicken chorioallantoic membrane assay, suggesting the involvement of a cyclooxygenase-2-independent mechanism in the in vivo antiangiogenic effects of celecoxib.     

顺铂诱导人卵巢癌SKOV3和SKOV3/DDP细胞内质网应激差异的研究

目的研究顺铂诱导人卵巢癌SKOV3和SKOV3/DDP细胞内质网应激的差异。方法顺铂分别作用SKOV3组、SKOV3/DDP组细胞0 h、12 h、24 h。MTT检测两种细胞对顺铂敏感性差异;Western blot方法检测并比较内质网应激相关蛋白表达;RT-PCR方法检测顺铂对各时间点细胞的XBP-1表达。结果顺铂诱导两种细胞内质网应激存在显著差异。顺铂引起SKOV3细胞中内质网应激相关蛋白明显活化;而对SKOV3/DDP细胞中内质网应激相关蛋白没有明显影响;顺铂诱导SKOV3/DDP中XBP-1明显表达上调。结论顺铂诱导的内质网应激相关基因的表达差异可能是卵巢癌细胞耐药机制之一。     

三氧化二砷诱导卵巢癌细胞系SKOV3细胞凋亡的作用和机制

目的观察三氧化二砷(ATO)诱导人卵巢癌细胞系SKOV3细胞的凋亡作用和凋亡通路分子caspase 3、PARP,凋亡相关蛋白p-AKT、AKT蛋白表达的变化。方法分别用不同剂量的三氧化二砷作用人卵巢癌细胞系SKOV3细胞,应用MTT比色法检测培养48 h的细胞存活率,应用流式细胞仪测定培养48 h细胞凋亡的变化,免疫印迹法检测凋亡蛋白caspase 3、PARP和凋亡相关蛋白p-AKT、AKT的表达情况。结果 MTT示三氧化二砷能明显抑制SKOV3细胞增殖;流式细胞术显示三氧化二砷诱导SKOV3细胞凋亡,且具有明显的剂量依赖性;Western blotting检测发现药物能显著下调caspase 3、PARP、p-AKT的表达水平。结论三氧化二砷能显著抑制人卵巢癌细胞系SKOV3细胞增殖,诱导其凋亡,激活凋亡通路分子caspase 3、PARP,下调p-AKT蛋白表达水平,这可能是三氧化二砷诱导人卵巢癌细胞SKOV3细胞凋亡的作用机制。     

Inhibition of autophagy sensitizes MDR-phenotype ovarian cancer SKVCR cells to chemotherapy

Autophagyis an intracellular lysosomal degradation pathway where its primary function is to allow cells to survive under stressful conditions. Autophagy is, however, a double-edge sword that can either promote cell survival or cell death.Chemoresistanceis a major challenge in the clinical treatment of ovarian cancer, of which the underlying mechanisms remain unknown.ObjectiveThe aim of the present study was to explore the role of autophagy in vincristine (VCR) resistant ovarian cancer cells.MethodsThe SKOV3 parental cell line and SKVCR, the VCR-resistant ovarian carcinoma cells were used. 3-MA (3-Methyladenine) and CQ (Chloroquine) were also used as autophagy inhibitors. CCK8 (Cell Counting Kit-8) was used to detect cell viability, quantitative real-time PCR and Western blot were used to detect the expressions of mRNA and protein, MDC staining and flow cytometry were used to detect autophagy and apoptosis, respectively.ResultsCompared with parental SKOV3 cells, SKVCR cells showed Multidrug Resistance (MDR). SKVCR cells demonstrated higher autophagy levels than SKOV3 cells, which could be inhibited by 3-MA and CQ. In SKVCR cells, VCR increased apoptosis levels further, 3-MA and CQ inhibited autophagy and potentiated the cytotoxicity by VCR. Moreover, 3-MA and CQ overcame the acquired VCR resistance in SKVCR cells by enhancing VCR-induced cytotoxicity, and promote apoptosis.ConclusionsOur data indicate that autophagy has a protective role in the multi-drug resistant SKVCR cells. The inhibition of autophagy increases the killing effects of VCR by increasing apoptosis and inhibiting autophagy, suggesting a better strategy for the treatment of drug-resistant SKVCR cells.     

Diarylureas are small-molecule inhibitors of insulin-like growth factor I receptor signaling and breast cancer cell growth

In breast and certain other cancers, receptor tyrosine kinases, including the insulin-like growth factor I receptor (IGF-IR), play an important role in promoting the oncogenic process. The IGF-IR is therefore an important target for developing new anti-breast cancer therapies. An initial screening of a chemical library against the IGF-IR in breast cancer cells identified a diaryl urea compound as a potent inhibitor of IGF-IR signaling. This class of compounds has not been studied as inhibitors of the IGF-IR. We studied the effectiveness of one diaryl urea compound, PQ401, at antagonizing IGF-IR signaling and inhibiting breast cancer cell growth in culture and in vivo. PQ401 inhibited autophosphorylation of the IGF-IR in cultured human MCF-7 cells with an IC50 of 12 micromol/L and autophosphorylation of the isolated kinase domain of the IGF-IR with an IC50 <1 micromol/L. In addition, PQ401 inhibited the growth of cultured breast cancer cells in serum at 10 micromol/L. PQ401 was even more effective at inhibiting IGF-I-stimulated growth of MCF-7 cells (IC50, 6 micromol/L). Treatment of MCF-7 cells with PQ401 was associated with a decrease in IGF-I-mediated signaling through the Akt antiapoptotic pathway. Twenty-four hours of treatment with 15 micromol/L PQ401 induced caspase-mediated apoptosis. In vivo, treatment with PQ401 (i.p. injection thrice a week) reduced the growth rate of MCNeuA cells implanted into mice. These studies indicate that diaryl urea compounds are potential new agents to test in the treatment of breast and other IGF-I-sensitive cancers.     

The dietary isothiocyanate sulforaphane targets pathways of apoptosis, cell cycle arrest, and oxidative stress in human pancreatic cancer cells and inhibits tumor growth in severe combined immunodeficient mice

Anticancer effects of the dietary isothiocyanate sulforaphane were investigated in the human pancreatic cancer cell lines MIA PaCa-2 and PANC-1. Sulforaphane-treated cells accumulated in metaphase as determined by flow cytometry [4C DNA content, cyclin A(-), cyclin B1(+), and phospho-histone H3 (Ser(10))(+)]. In addition, treated cells showed nuclear apoptotic morphology that coincided with an activation of caspase-8, loss of mitochondrial membrane potential, and loss of plasma membrane integrity. The initial detection of caspase-3 cleavage occurring in G(2)-M arrest was independent of a change in phospho-cdc2 (Tyr(15)) protein; consequently, sulforaphane treatment combined with UCN-01 had no significant impact on cellular toxicity. Incubations at higher sulforaphane doses (>10 micromol/L) resulted in cleavage of caspase-3 in the G(1) subpopulation, suggesting that the induction of apoptosis and the sulforaphane-induced mitosis delay at the lower dose are independently regulated. Cellular toxicity in MIA PaCa-2, and to a greater extent in PANC-1, was positively correlated with a decrease in cellular glutathione levels, whereas sustained increases in glutathione observed in MIA PaCa-2 cells or the simultaneous incubation with N-acetyl-L-cysteine in PANC-1 cells were associated with resistance to sulforaphane-induced apoptosis. Daily sulforaphane i.p. injections (375 micromol/kg/d for 3 weeks) in severe combined immunodeficient mice with PANC-1 s.c. tumors resulted in a decrease of mean tumor volume by 40% compared with vehicle-treated controls. Our findings suggest that, in addition to the known effects on cancer prevention, sulforaphane may have activity in established pancreatic cancer.     

The sulindac derivatives OSI-461, OSIP486823, and OSIP487703 arrest colon cancer cells in mitosis by causing microtubule depolymerization

Exisulind (sulindac sulfone) and three highly potent derivatives, OSI-461 (CP461), OSIP486823 (CP248), and OSIP487703, inhibit growth and induce apoptosis in SW480 human colon cancer cells, with IC(50)s of 200, 2, 0.1, and 0.003 micromol/L, respectively. The latter three compounds, but not exisulind, induce marked M-phase cell cycle arrest in these cells. This effect seems to be independent of the known ability of these compounds to cause activation of protein kinase G. When tested at twice their IC(50) concentration for growth inhibition, OSI-461, OSIP486823, and OSIP487703 cause depolymerization of microtubules in interphase cells, inhibit spindle formation in mitotic cells, and induce multinucleated cells. In vitro tubulin polymerization assays indicate that all three compounds interact with tubulin directly to cause microtubule depolymerization and/or inhibit de novo tubulin polymerization. These results suggest that the dual effects of OSI-461, OSIP486823, and OSIP487703 on impairment of microtubule functions and protein kinase G activation may explain the potent antiproliferative and apoptotic effects of these compounds in cancer cells.     

RMP通过AMPK通路调节线粒体稳态和氧化应激诱导卵巢癌细胞增殖与凋亡的机制研究

目的 探讨RPB5调节蛋白（RPB5-mediating protein,RMP）对卵巢癌细胞增殖与凋亡的影响以及通过腺苷酸激活蛋白激酶（adenosine 5’-monophosphate (AMP)-activated protein kinase,AMPK）通路调节线粒体稳态和氧化应激的作用机制。方法 实时荧光定量PCR(qRT-PCR)法检测人输卵管上皮永生化细胞FTE-187与人卵巢癌细胞系SKOV3,A2780和HO8910中RMP基因的表达。以SKOV3细胞作为研究对象,利用siRNA技术敲低SKOV3细胞中RMP的表达,再通过qRT-PCR法验证RNAi效率。通过平板克隆形成实验和流式细胞技术观察敲低RMP表达后对SKOV3细胞增殖能力、周期分布及凋亡能力的影响。通过激光共聚焦显微镜观察敲低RMP表达后SKOV3细胞中线粒体形态的变化。Western blot进一步证实RMP调控线粒体稳态相关蛋白AMPK和p-AMPK以及凋亡蛋白Bcl-2和Bax的表达。采用ROS荧光法检测敲低RMP表达后对SKOV3细胞内ROS水平的影响。结果 RMP在FTE-187细胞中的表达水平...     

抑制葡萄糖调节蛋白78基因表达逆转卵巢癌顺铂耐药作用的实验研究

目的探讨以葡萄糖调节蛋白78(GRP78)基因为靶向的RNA干扰(RNAi)抑制GRP78基因的表达,对人卵巢癌顺铂耐药细胞株SKOV3/DDP的影响。方法以GRP78基因为靶向的pSilencerTM3.0-H1-GRP78 siRNA重组质粒的构建,脂质法转染至细胞中;RT-PCR及Western blot方法检测GRP78 mRNA及蛋白表达;Western blot方法检测CHOP蛋白表达;MTT法检测不同浓度顺铂作用下细胞存活率,计算IC50及耐药指数。结果 RT-PCR及Western blot检测转染GRP78 siRNA重组质粒24 h、48 h7、2 h均能明显抑制SKOV3/DDP细胞GRP78基因表达,其中48h抑制效果最为明显;抑制SKOV3/DDP细胞GRP78基因表达能上调CHOP蛋白表达;顺铂作用24h,SKOV3/DDP细胞的IC50(26.13μg/ml)是其亲本SKOV3细胞IC50(8.25μg/ml)的3.1倍;转染pSH1Si-GRP78重组质粒后SKOV3/DDP细胞IC50(11.62μg/ml)明显降低。结论转染GRP78 siRNA重组质粒有效抑制SKOV3/DDP细胞GRP78基因表达;抑制GRP78基因表达能逆转SKOV3/DDP细胞的顺铂耐药性。