MDM2 sensitizes a human ovarian cancer cell line

OBJECTIVES: The purpose of this study was to determine whether overexpression of MDM2 could sensitize the ovarian cancer cell line A2780. METHODS: The wild-type p53-expressing cell line A2780 was stably transfected with pCMV-MDM2 (A2780-MDM2) or pCMV (A2780-V) as control. MTT assay and clonogenic survival assay were used to measure the cisplatin sensitivity. FACS and host cell (CAT) reactivation assay were used to estimate the change of cell cycle and ability of repairing cisplatin-induced DNA damage. RESULTS: Parental A2780 and A2780-V had similar cisplatin sensitivities, whereas A2780-MDM2 was two- to threefold more sensitive to cisplatin. Repair of cisplatin-induced DNA damage was reduced in A2780 cells overexpressing MDM2, compared to A2780 cells in which wild-type p53 function was intact. After cisplatin treatment, A2780-MDM2 cells showed a pronounced S-phase arrest; however, A2780 cells with intact wild-type p53 arrested primarily in G2/M phase. CONCLUSIONS: MDM2 overexpression can increase cisplatin cytotoxicity in A2780, with loss of G1/S checkpoint control and decreased cisplatin-DNA adduct repair. This suggests that ovarian cancers that overexpress MDM2 may be amenable to treatment with platinum compounds.     

TWEAK调控凋亡增加上皮性卵巢癌细胞对铂类药物敏感性的研究

目的：探讨肿瘤坏死因子样凋亡微弱诱导剂（TWEAK）在调控上皮性卵巢癌（EOC）细胞对顺铂（DDP）敏感性中发挥的作用。方法：不同浓度TWEAK刺激A2780/cDDP细胞后,采用CCK-8法检测细胞的增殖能力及DDP半数抑制浓度（IC50）的变化;采用流式细胞术检测细胞凋亡率的变化;采用透射电镜检测细胞核染色质形态和凋亡小体的变化;Western blot法检测细胞凋亡相关蛋白caspase 3的活化情况。结果：TWEAK对A2780/cDDP细胞的增殖能力无影响,但能显著增加A2780/cDDP细胞对DDP的敏感性。流式结果显示,随着TWEAK剂量增加,A2780/cDDP细胞的凋亡显著增加。TWEAK刺激后A2780/cDDP细胞中caspase 3活化体表达增加,细胞核染色质发生形态变化,诱导了细胞的凋亡及凋亡小体形成。结论：TWEAK通过活化凋亡相关通路,促进EOC细胞凋亡,提高了DDP耐药EOC细胞对DDP的敏感性。这可能为临床开创逆转EOC铂类耐药的治疗新途径提供理论依据。     

Time-dependent changes in factors involved in the apoptotic process in human ovarian cancer cells as a response to cisplatin

OBJECTIVES: Apoptosis is believed to be a major mechanism of cisplatin-induced cell death. We investigated the kinetics of apoptosis in four human ovarian cancer cell lines treated with cisplatin to obtain insight into the role and the behavior of a variety of factors involved in this process. METHODS: The cell lines A2780, H134, and IGROV-1 (all wild-type p53) and OVCAR-3 (mutant p53) were exposed to cisplatin for 1 h and the antiproliferative effects were measured after 96 h. At various time points up to 96 h after the 1-h exposure to the individual 90% growth-inhibiting cisplatin concentrations, FACS analysis and May-Grünwald Giemsa staining were carried out to determine the extent of apoptosis. At the same time points protein expression levels of p53, p21/WAF1, Bax, and Bcl-2 and the activity of caspase-3 were measured. FACS analysis was also carried out to determine changes in cell cycle distribution as a response to cisplatin. RESULTS: The four cell lines differed in sensitivity to cisplatin. A2780 was the most sensitive and IGROV-1 was the least sensitive. In contrast, IGROV-1 cells showed the highest percentage of apoptosis (30-40%), while A2780 had the lowest percentage (6-14%) (r = 0.99). The occurrence of apoptosis was not dependent on functional p53. Of interest, caspase-3 activity was in line with the percentage of apoptosis and preceded DNA fragmentation and the visualization of condensed nuclei. Wild-type p53 cells accumulated in the S phase, while OVCAR-3 arrested in the G2/M phase. The protein expression levels of p53, p21/WAF1, Bax, and Bcl-2 varied in time, but were not related to the apoptotic behavior of the cells. Upregulation of p53 was already evident before activation of caspase-3. CONCLUSIONS: Time-dependent changes in the various factors involved in the apoptotic process induced by equitoxic doses of cisplatin vary strongly among the cell lines. Caspase-3 activation plays an important role in cisplatin-induced apoptosis and this precedes morphological changes. The ability of cells to enter apoptosis, however, does not seem to predict sensitivity to cisplatin.     

PI3K／Akt／mTOR信号转导通路与卵巢癌研究进展

磷脂酰肌醇3激酶,蛋白激酶B／哺乳动物雷帕霉素靶体蛋白（P13K／Akt／mTOR）信号转导通路通过PTEN基因功能的失常或者被其他信号激活后,抑制细胞凋亡,促进细胞周期运行,致细胞增殖,促进血管形成和恶性肿瘤的侵袭和转移,在卵巢癌的发生和发展中发挥重要作用,且与卵巢癌化疗耐药密切相关。因此该通路中的受体及激酶可能成为卵巢癌抗癌药物的潜在靶点,随着对该通路研究的逐渐深入以及抑制剂的发现和发明,针对该信号转导通路开发新的肿瘤治疗药物,靶向基因治疗,以及寻找降低化疗耐药的方法．无疑对卵巢癌治疗具有重要意义。     

AKT involvement in cisplatin chemoresistance of human uterine cancer cells

OBJECTIVE: The aim of this study was to investigate the possible involvement of Akt activity and specific isoforms (Akt1, Akt2, and Akt3) in the resistance of human uterine cancer cells to cisplatin. METHODS: Two different endometrial (HEC-1-A and KLE) and one cervical (HeLa) cancer cell lines all known as wild-type PTEN (tumor suppressor phosphatase tensin homologue, a lipid phosphatase involved in the negative regulation of Akt activity) were used for these studies. RESULTS: Basal levels of Akt1, Akt2, and Akt3 mRNAs were determined by real-time quantitative RT-PCR studies and Western blot analyses were carried out to determine protein abundance of each isoforms. Akt1 mRNA and protein were present in all cell lines studied. Akt2 and Akt3 mRNAs and proteins were strongly expressed in KLE cells. Surprisingly, Akt phosphorylation was found in KLE expressing high levels of wild-type PTEN protein. KLE cells remained resistant to PI 3-K inhibitor, indicating that Akt phosphorylation might be, in part, independent of PI 3-K in this cell line. Cisplatin induced apoptosis in HeLa and HEC-1-A cells, but KLE cells expressing Akt2 and Akt3 remained more resistant to cisplatin. Knockout of Akt isoforms using specific siRNA technology increased the sensitivity of KLE cells toward cisplatin and caused a significant induction of cell death. CONCLUSION: Taken together, these results suggest that specific Akt isoforms such as Akt2 and Akt3 might be involved in chemoresistance to cisplatin and that these isoforms could be putative targets for gene therapy in uterine cancers.     

稳定转染PTEN基因后对卵巢上皮性癌细胞磷酸酰肌醇3激酶/蛋白激酶B信号传导通路的影响

目的 研究外源性PTEN基因稳定转染卵巢上皮性癌(卵巢癌)细胞后,对卵巢癌细胞磷酸酰肌醇3激酶(PI3K)/蛋白激酶B(Akt)信号传导通路的影响.方法 构建表达野生型PTEN基因的重组载体pcDNA3.1A-PTEN质粒,并转染卵巢癌细胞株HO-8910细胞(重组载体组),以转染空载体pcDNA3.1A质粒(空载体组)作为阴性对照,以未转染质粒(空白组)作为空白对照.采用逆转录(RT)PCR技术检测3组细胞中PTEN、Akt1、Akt2、PI3K mRNA的表达水平,蛋白印迹法检测3组细胞中PTEN蛋白的表达强度,四甲基偶氮唑蓝(MTT)比色法检测3组细胞的生长情况[以吸光度(A)值表示,A值越大表示生长速度越快].结果 表达野生型PTEN基因的重组载体pcDNA3.1A-PTEN质粒,经测序证实构建成功.重组载体组细胞中PTEN mRNA的表达水平为(17372±23)copy/ml,高于空载体、空白组[分别为(39±1)、(78±4)copy/ml],差异均有统计学意义(P＜0.05);重组载体组细胞中PTEN蛋白的表达强度也明显高于空载体、空白组.重组载体组细胞中Akt1、Akt2、PI3KmRNA的表达水平分别为(28±2)、(7±1)、(61±2)copy/ml,低于空载体[分别为(115±5)、(18±2)、(84±2)copy/ml]、空白组[分别为(77±4)、(17±2)、(1349±7)copy/m1],差异均有统计学意义(P＜0.05).培养第5天,重组载体组细胞生长速度(A值)为90 158±47,低于空载体、空白组(分别为148 251±65、250 115±62),差异均有统计学意义(P＜0.05).结论 转染表达野生型PTEN基因的重组载体能有效提高卵巢癌HO-8910细胞中PTEN mRNA和蛋白的表达,抑制细胞生长,并通过显著降低Akt1、Akt2、PI3K mRNA的表达水平,明显抑制PI3K/Akt信号传导通路.     

A small molecule Smac mimic potentiates TRAIL-mediated cell death of ovarian cancer cells

OBJECTIVES: Ovarian cancer remains a leading cause of death in women and development of new therapies is essential. Second mitochondria derived activator of caspase (Smac) has been described to sensitize for apoptosis. We have explored the proapoptotic activity of a small molecule mimic of Smac/DIABLO on ovarian cancer cell lines (A2780 cells and its chemoresistant derivatives A2780/ADR and A2780/DDP), cancer cell lines and in primary ovarian cancer cells. METHODS: The effects of a small molecule mimic of Smac/DIABLO on ovarian cancer cell lines and primary ovarian cancer cells were determined by cell proliferation, apoptosis and biochemical assays. RESULTS: This compound added alone elicited only a weak proapoptotic effect; however, it strongly synergizes with tumor necrosis factor-related apoptosis inducing ligand (TRAIL) or agonistic TRAILR2 antibody (Lexatumumab) in inducing apoptosis of ovarian cancer cells. CONCLUSIONS: These observations suggest that small molecule mimic of Smac/DIABLO could be useful for the development of experimental strategies aiming to treat ovarian cancer. Interestingly, in addition to its well known proapoptotic effects, Smac/DIABLO elicited a significant increase of pro-caspase-3 levels.     

p53基因转染对卵巢癌MDR细胞药物敏感性及恶性表型的影响

研究 ｐ５３基因导入已知内源背景的肿瘤 ＭＤＲ细胞所致的恶性表型和ＭＤＲ表型的改变及两者的关系。方法：用磷酸钙沉淀法将含有野生型及全长反义 ｐ５３ｃＤＮＡ的逆转录病毒载体ｐＤＷｐ５３及 ｐＤＡｐ５３转染病毒包装细胞 ＰＡ３１７,测定病毒滴度。用此病毒感染卵巢癌多药耐药细胞株Ａ２７８０／ＡＤＭ,Ｓｏｕｔｈｅｒｎ Ｂｌｏｔ鉴定,检测转导基因后细胞株的恶性度、多药耐药性等情况。结果：野生型及反义全长ｐ５３ｃＤＮＡ均转入 ＰＡ３１７细胞获得效价为（１－ １．５） Ｘ１０５ＣＦＵ／ｍｌ的前病毒,以此感染卵巢癌多药耐药细胞株Ａ２７８０／ＡＤＭ,Ｓｏｕｔｈｅｍ Ｂｌｏｔ证实ｐ５３基因导入该细胞并整合到基因组ＤＮＡ中,进一步测试观察到：①导入野生型ｐ５３基因的Ａ２７８０／ＡＤＭ细胞生长被抑制、恶性度降低,细胞形态和生长曲线改变,软琼脂集落形成率及裸鼠接种成瘤率降低;②细胞多药耐药性减弱,对ＡＤＭ耐药性下降,Ｐ－ｇｐ表达降低;③反义ｐ５３的导入也对Ａ２７８０／ＡＤＭ恶性度有一定的影响;④野生型ｐ５３导致的ＭＤＲ细胞恶性表型与ＭＤＲ水平的降低似有平行关系。结论：ｐ５３基因对肿瘤细胞ｍｄｒ－ １基因的表达可能起调控作用,ｐ５３发生突变的 Ｍ?     

Adenovirus-mediated p53 growth inhibition of ovarian cancer cells is independent of endogenous p53 status.

OBJECTIVE:The aim of this study was to determine the effect of transfection of adenovirus-mediated wild-type p53 into ovarian cancer cells with both wild-type and mutant endogenous p53. STUDY DESIGN: Eight human ovarian cancer cell lines were used: three with p53 mutations, one that is p53 null, and four with wild-type p53. The recombinant p53 adenovirus (Adp53) contains the cytomegalovirus promoter, wild-type p53 cDNA, and SV40 polyadenylation signal in a minigene cassette inserted into the E1-deleted region of modified Ad5. The transduction efficiency of cells was assessed using a beta-gal-containing adenovirus. Cell-counting assays were used to evaluate the effect of transfection with Adp53 on the growth of cells. P53 expression was evaluated using Western blot. Cell cycle analysis and apoptosis studies were done using a tunnel-based assay and fluorescent activated cell sorting. RESULTS: Transduction efficiencies varied between cell lines. More than 90% growth inhibition occurred in seven of eight cell lines after infection with adenovirus-mediated p53 if a viral dose leading to at least 50% of cells infected was used. Regardless of endogenous p53 status, apoptosis occurred in cells infected with p53. CONCLUSIONS: Ovarian cancer cells are growth inhibited by transfection with adenovirus-mediated p53 regardless of their endogenous p53 status. Growth inhibition is related to transduction efficiency.     

3-甲基腺嘌呤对顺铂诱导卵巢癌细胞凋亡影响的研究

目的:探讨自噬抑制剂3-甲基腺嘌呤(3-MA)对顺铂(DDP)诱导的卵巢癌SKOV3细胞凋亡的影响。方法:体外培养卵巢癌SKOV3细胞,用PI3K/Akt通路抑制剂3-MA预处理SKOV3细胞3h,再用DDP作用48h,经Annexin V-FITC/PI双染色流式细胞仪检测凋亡率,TUNEL法检测凋亡指数(AI),Western blot检测凋亡蛋白caspase3,caspase9的表达。结果:3-MA预处理后,DDP诱导的卵巢癌SKOV3细胞凋亡率为(37.04±7.15)%,凋亡指数为58.0±5.20,而单用DDP组凋亡率为(10.46±0.65)%,凋亡指数为26.0±3.46。3-MA预处理后,DDP诱导的SKOV3细胞凋亡率和凋亡指数均较单用DDP组明显提高(P<0.05)。caspase3,caspase9蛋白的表达也明显增强。结论:3-MA可上调caspase3,caspase9蛋白的表达,通过内源性途经增强DDP促卵巢癌细胞SKOV3的凋亡活性。     

PTEN基因对卵巢癌耐药细胞系C13K顺铂耐药性的影响

目的:探讨第10号染色体上PTEN对人卵巢癌顺铂耐药细胞株C13K顺铂耐药性的逆转作用。方法:将野生型PTEN基因真核表达质粒在脂质体介导下转染人卵巢癌耐药细胞系C13K细胞,同时以转染空载体和未转染C13K细胞作为对照,分别应用逆转录聚合酶链式反应(RT-PCR)及蛋白印迹法(W estern blot)检测PTEN mRNA及蛋白表达水平,对转染细胞株进行四甲基偶氮噻唑蓝(MTT)实验,观察PTEN基因对肿瘤细胞生长的抑制作用和C13K细胞对顺铂药物敏感性的影响,流式细胞仪(FACS)分析细胞的凋亡。结果:转染48 h后,与对照组相比,转染野生型PTEN基因能明显增加C13K细胞PTEN mRNA和蛋白的表达,差异有统计学意义(P<0.05);MTT法显示,转染野生型PTEN基因的C13K细胞生长明显慢于转染空载体和未转染的C13K细胞,转染PTEN的C13K细胞对顺铂的敏感性显著增加;FACS分析显示,顺铂作用24h后,转染PTEN基因能够显著提高C13K细胞凋亡率。结论:转染野生型PTEN质粒能有效地提高C13K细胞内PTEN的表达,恢复细胞对顺铂的敏感性。     

Phosphatidylinositol 3-kinase/Akt regulates the balance between plasminogen activator inhibitor-1 and urokinase to promote migration of SKOV-3 ovarian cancer cells

OBJECTIVES: Increased levels of urokinase-type plasminogen activator (uPA) are associated with shortened overall survival in ovarian cancer patients. Additionally, elevated levels of the serine protease inhibitor (serpin), plasminogen activator inhibitor-1 (PAI-1), a uPA inhibitor, have also been correlated with an unfavorable prognosis in ovarian cancer. Therefore, it is critical to understand the signaling pathways that regulate PAI-1 and uPA expression in cancer cell migration-invasion. METHODS: We studied the PI3K/Akt, Rho kinase/ROCK, p38 MAPK and MEK pathways and their modulation of PAI-1 and uPA expression and wound-induced cell migration in SKOV-3 ovarian cancer cells. The PI3K/Akt pathway was further examined using pharmacological inhibitors (LY294002 and wortmannin), Akt siRNA, constitutively active Akt adenovirus and treatment with IGF-1/insulin in the SKOV-3 cells. RESULTS: The PI3K/Akt pathway negatively regulates PAI-1 expression and positively correlates with migratory abilities and uPA expression in SKOV-3 cells. A reduction in active Akt results in an increase in PAI-1 expression coupled with a decrease in uPA expression to ultimately result in reduced cell migration and invasion. By contrast, an increase in Akt activity reduces PAI-1 expression and results in an increase in SKOV-3 wound-induced cell migration. Furthermore, IGF-1 and insulin stimulated SKOV-3 migration by altering the balance between uPA and PAI-1 to favor uPA, and the enhanced migration was attenuated by treatment with LY294002 indicating PI3K/Akt in this pathway. CONCLUSIONS: These results suggest an overall ovarian tumor-protective role for PAI-1, and that the PI3K/Akt signaling pathway regulates the ratio of PAI-1:uPA to either increase or decrease cell migration.     

APE1 siRNA增强卵巢癌细胞铂类敏感性的实验研究

目的:本研究通过观察脱嘌呤/脱嘧啶核酸内切酶(APE1/Ref-1)小分子干扰核糖核酸(siRNA)对卵巢癌细胞中APE1表达水平及顺铂敏感性的影响,探讨以APE1为靶点的基因治疗在卵巢癌化疗增敏中的临床应用前景。方法:应用RNAi技术抑制卵巢癌顺铂敏感株A2780和顺铂耐药株A2780/CP70中APE1的表达,并用MTT法及TUNEL等技术检测APE1 siRNA对卵巢癌细胞铂类敏感性的影响。结果:MTT药物敏感试验表明,20MOI和40MOI APE1 siRNA处理后,A2780细胞顺铂IC50值由对照组的31.62μmol/L分别降低为13.38μmol/L和3.48μmol/L,有统计学差异(P<0.01)。20MOI和40MOI APE1 siRNA处理后,A2780/CP70细胞的顺铂IC50值分别为39.73μmol/L和12.43μmol/L,较对照组(64.20μmol/L)分别下降了38.12%和80.64%,有统计学差异(P<0.01)。TUNEL凋亡原位检测表明,40MOI APE1 siRNA处理后,A2780和A2780/CP70细胞的凋亡指数分别为(42.16±3.61)%和(46.11±3.81)%,分别是DDP组的3.57倍、4.94倍,有统计学差异(P<0.01)。结论:抑制APE1表达能显著增加卵巢癌细胞对顺铂的敏感性,APE1可能是逆转卵巢癌铂类耐药的有效靶点。     

微小RNA-3619-5p通过靶向作用于p21基因对卵巢癌细胞生长的影响

目的:探讨微小RNA-3619-5p(miR-3619-5p)过表达对卵巢癌细胞系A2780和SKOV3中p21基因的上调作用及对卵巢癌细胞生长的影响。方法:使用Lipofectamine 3000分别向卵巢癌细胞系A2780和SKOV3瞬时转染miR-3619-5p(实验组)或者dsControl(对照组)。通过实时荧光定量聚合酶链反应(q RT-PCR)检测p21、细胞周期依赖性激酶4(CDK4)和细胞周期蛋白D1(Cyclin D1)mRNA的表达情况。蛋白质印迹(Western blotting)检测p21、CDK4和Cyclin D1蛋白的表达情况。流式细胞术检测对照组和实验组细胞周期分布差异和细胞凋亡情况。EdU增殖实验和集落形成实验检测细胞增殖能力。结果:与对照组相比,转染miR-3619-5p后2种细胞系中p21 mRNA均显著升高(P0.01),而CDK4和Cyclin D1 mRNA的表达均明显降低(P0.01)。Western blotting实验结果与qRT-PCR结果一致。与对照组相比,转染miR-3619-5p后,位于S期和G_2/M期的细胞比例明显下降,位于G_0/G_1期的细胞比例明显增大,细胞凋亡率明显升高。EdU增殖实验和集落形成实验均显示,与对照组相比,转染miR-3619-5p的卵巢癌细胞的增殖能力明显下降(P0.05)。结论:miR-3619-5p可通过激活卵巢癌细胞中p21蛋白的表达抑制卵巢癌细胞的生长。     

E-钙粘素介导的细胞粘附通过EGFR激活卵巢癌细胞PI3K-Akt信号通路

目的研究E-钙粘素介导的细胞粘附对卵巢癌细胞Akt及其上游的磷脂酰肌醇3-激酶(phosphatidylinositol 3-Kinase,PI3K)信号的激活及对卵巢癌细胞增殖的作用。方法基于卵巢癌细胞株CaOV-3构建Ca2+依赖性细胞粘附模型;Western blot和免疫沉淀法检测E-钙粘素介导的细胞粘附通过表皮生长因子受体(epidermal growth factor recep-tor,EGFR)对PI3K-Akt的激活;同时通过阻断该通路的关键组分观察对卵巢癌细胞增殖的影响。结果(1)E-钙粘素介导的细胞粘附可激活卵巢癌细胞内部的EGFR-PI3K-Akt信号通路;(2)应用E-钙粘素抗体或PI3K抑制剂处理的CaOV-3细胞株表现出生长受阻的现象,72h时细胞生长抑制率分别达73.5%和78.8%。结论E-钙粘素激活卵巢癌细胞EGFR-PI3K-Akt相关的信号转导通路对肿瘤细胞的增殖有重要作用。干预该信号通路的关键组分显著抑制细胞生长,为卵巢癌的靶向治疗提供了新的有价值的干预靶点。     

PTEN基因逆转卵巢上皮性癌细胞耐药的机制研究

目的通过检测PTEN基因在卵巢上皮性癌（卵巢癌）顺铂敏感细胞株0V2008及0V2008配对的顺铂耐药细胞株C13K中的表达,探讨转染PTEN基因能否逆转C13K细胞对顺铂的耐药及其相关机制。方法半定量RT-PCR技术和蛋白印迹法检测0V2008和C13K细胞中PTENmRNA和蛋白的表达。将野生型PTEN基因真核表达质粒在脂质体介导下转染C13K细胞,同时以转染空载体和未转染的C13K细胞作为对照,分别应用RT-PCR技术检测各组细胞PTENmRNA表达的变化,应用蛋白印迹法检测各组细胞PTEN、蛋白激酶B（AKT）及磷酸化AKT（p-AKT）蛋白表达的变化;四甲基偶氮唑蓝（M1Tr）比色法观察转染PTEN基因后C13K细胞对顺铂敏感性的变化,流式细胞仪分析顺铂作用后的细胞凋亡情况。结果（1）PTENmRNA在0V2008和C13K细胞中的表达水平分别为1．02±0.05和0．45±0.03,而0V2008、C13K细胞中PTEN蛋白的表达水平分别为1.02±0.07、0．55±0．03,两种细胞PTENmRNA和蛋白的表达水平分别比较,差异均有统计学意义（P〈0．05）。（2）PTEN基因转染48h后,C13K细胞中PTENmRNA、蛋白的表达水平分别为2.04±0．10和0．94±0．04,分别与转染空载体和未转染的C13K细胞比较,差异均有统计学意义（P〈0．01）;p-AKT蛋白的表达水平（0.94±0．07）较转染空载体（1．66±0．10）和未转染（1．68±0．14）的C13K细胞显著降低（P〈0．05）。（3）转染PTEN基因的C13K细胞对顺铂的半数抑制浓度（IC50）为（7.2±0．3）μmol／L,明显高于转染空载体和未转染的C13K细胞[分别为（12．7±0．4）、（13．0±0．3）μmol／L,P〈0,05]。（4）顺铂作用24h后,转染PTEN基因、转染空载体和未转染的C13K细胞的凋亡率分别为（41.7±0.9）％、（18．6±0．7）％和（15,3±0．8）％,前者明显高于后两者（P〈0．01）。结论PTEN基因在0V2008细胞中的表达明显高于C13K细胞。转染野生型PTEN基因能有效提高C13K细胞内PTEN基因的表达,并通过降低C13K细胞中AKT磷酸化的水平恢复C13K细胞对顺铂的敏感性。     

靶向Akt1的siRNA抑制卵巢癌细胞系生长的体外研究

目的:探讨靶向Akt1的siRNA抑制人卵巢癌细胞系SKOV3的Akt1表达后,对细胞增殖和侵袭的抑制作用。方法:将Akt1特异性siRNA转染人卵巢癌细胞系SKOV3,Real-time PCR检测Akt1 mRNA表达,Western blot和免疫荧光技术检测Akt1、Akt2、PI3Kp85α和Ki-67的蛋白表达;MTT法和Annexin V标记评价其对细胞增殖活性和凋亡的影响,流式细胞法分析细胞周期变化,Transwell法分析对侵袭能力的影响。结果:转染Akt1 siRNA后可明显下调Akt1 mRNA表达;Akt1、PI3Kp85α、Akt2和Ki-67蛋白的表达水平均明显降低(P<0.01);卵巢癌细胞增殖活性明显降低,细胞周期出现G0/G1阻滞,并诱发细胞凋亡,细胞侵袭能力减弱(P<0.01)。结论:靶向Akt1的siRNA可显著抑制卵巢癌细胞Akt1的表达,进而抑制肿瘤细胞的生长和侵袭,有望成为卵巢癌基因治疗的分子靶点。     

Downregulation of miR-503 contributes to the development of drug resistance in ovarian cancer by targeting PI3K p85

Objective

Cisplatin is an important chemotherapeutic agent frequently used in the treatment of ovarian cancer. However, resistance to cisplatin is an obstacle to the treatment of ovarian cancer. Recently, many studies have demonstrated that microRNAs (miRNAs) are involved in the drug resistance of ovarian cancer cells. In this study, we explored the role of miR-503 in cisplatin-resistant ovarian cancer.

Materials and Methods

To investigate the relationship between miR-503 expression and the sensitivity of ovarian cancer cells to cisplatin, the cells were transfected with miR-503 mimics/inhibitors. The relative expression of miR-503 RNA and its targeted gene PI3K mRNA were detected by real-time PCR (RT-PCR). Western blot was used to measure relevant protein levels. Flow cytometry and CCK-8 assay were used to analyze cell proliferation and apoptosis.

Results

MiR-503 expression was significantly downregulated in cisplatin-resistant ovarian cancer cell line SKOV3/DDP compared with parental SKOV3. Over-expression and knock-down of miR-503 partially regulated apoptotic activity and changed the cisplatin resistance of ovarian cancer cells. In exploring the underlying mechanisms of miR-503 in ovarian cancer cells’ resistance to cisplatin, we found that miR-503 can directly target PI3K p85 and participates in the regulation of the PI3K/Akt signaling pathway. In vivo, miR-503 agomirs combined with cisplatin treatment significantly reduced the growth of tumors compared with cisplatin alone.

Conclusions

Our data suggest that miR-503 might be a sensitizer to cisplatin treatment in ovarian cancer by targeting PI3K p85, thus giving a new insight into developing therapeutic strategies to overcome cisplatin resistance in ovarian cancer.