银杏内酯B通过阻抑PI3K/Akt/mTOR信号通路抑制胃癌HGC-27 细胞的恶性生物学行为

目的：探讨银杏内酯B（GKB）是否通过阻抑PI3K/Akt/mTOR信号通路抑制胃癌HGC-27细胞的增殖、凋亡、迁移及侵袭。方法：将HGC-27细胞分为对照、GKB低剂量（100 mg/L）、GKB高剂量（200 mg/L）、GKB高剂量（200 mg/L）+740Y-P（PI3K激活剂）、Ly294002（PI3K抑制剂）组。采用MTT、Edu、FCM、Transwell实验分别检测各组细胞的增殖、凋亡、迁移和侵袭能力,qPCR和WB法分别检测各组细胞中PI3K mRNA、Akt mRNA、mTOR mRNA和Ki-67、caspase-3、p-PI3K/PI3K、p-Akt/Akt、p-mTOR/mTOR蛋白的表达。构建胃癌HGC-27细胞裸鼠移植瘤模型,观察GKB对移植瘤生长的影响,WB法检测移植瘤组织中Ki-67、caspase-3、p-PI3K/PI3K、p-Akt/Akt、p-mTOR/mTOR蛋白的表达。结果：体外实验结果表明,与对照组相比,GKB低剂量组、GKB高剂量组、Ly294002组HGC-27细胞的增殖活力及细胞增殖率、迁移和侵袭细胞数,PI3K、Akt、mTOR mRNA表达,以及Ki-67、p-PI3K/PI3K、p-Akt/Akt、p-mTOR/mTOR蛋白表达均显著降低（均P<0.05）;细胞凋亡率、caspase-3蛋白表达均显著升高（均P<0.05）;740Y-P可部分逆转GKB对HGC-27细胞的抑制作用（均P<0.05）。荷瘤裸鼠实验结果显示,GKB可显著抑制HGC-27细胞裸鼠移植瘤的生长（P<0.05）,且可下调PI3K/Akt/mTOR通路相关蛋白的表达。结论：GKB可通过阻抑PI3K/Akt/mTOR信号通路而抑制胃癌HGC-27细胞增殖、迁移与侵袭并促进其凋亡。     

干扰小RNA沉默CAV1表达对人绒毛膜癌JEG-3细胞侵袭、迁移能力的影响及其作用机制研究

目的 探究干扰小RNA(siRNA)沉默小窝蛋白-1(CAV1)基因表达对人绒毛膜癌JEG-3细胞侵袭、迁移能力的影响及其可能的作用机制.方法 将人绒毛膜癌JEG-3细胞分为对照组(不进行转染)、阴性组(转染siRNA-NC)和siRNA-CAV1组(转染siRNA-CAV1).Transwell法检测下调CAV1表达对细胞侵袭、迁移能力的影响;实时定量PCR(qRT-PCR)检测转染细胞中CAV1 mRNA的表达水平;蛋白质印迹法(Western blot)检测细胞中CAV1、丝苏氨酸蛋白激酶(AKT)、雷帕霉素靶蛋白(MTOR)、核糖体p70S6激酶(p70S6K)、磷酸化AKT(p-AKT)、磷酸化MTOR(p-MTOR)、磷酸化p70S6K(p-p70S6K)蛋白的表达水平.结果 siRNA-CAV1组JEG-3细胞中CAV1 mRNA和蛋白的相对表达量均低于对照组(P﹤0.05);siRNA-CAV1组JEG-3细胞的侵袭数目、迁移数目均低于对照组(P﹤0.05);siRNA-CAV1组JEG-3细胞中AKT、MTOR、p70S6K以及磷酸化水平均低于对照组(P﹤0.05).结论 沉默CAV1表达可以抑制人绒毛膜癌JEG-3细胞的侵袭和迁移能力,该作用与AKT/MTOR/p70S6K信号通路有关.     

氟奋乃静通过自噬诱导U87胶质瘤细胞死亡及其机制探讨

目的：观察氟奋乃静（FPZ）通过自噬诱导U87胶质瘤细胞死亡的机制。方法体外培养U87胶质瘤细胞并经FPZ处理,采用细胞活力和集落形成方法分析细胞的生存率,采用Western blot检测自噬相关蛋白及PI3K/AKT/mTOR通路蛋白的表达。结果 FPZ处理后,U87胶质瘤细胞活力显著降低（P﹤0.05）,菌落数显著降低（P﹤0.05）;微管相关蛋白1轻链3-Ⅱ型（LC3-Ⅱ）显著增加,并呈时间和剂量依赖性;p-AKT水平及其下游p-mTOR水平显著下降,并呈时间依赖性。采用PI3K抑制剂LY294002处理U87胶质瘤细胞后,LC3-Ⅱ生成明显增加。结论 FPZ可通过抑制PI3K/AKT/mTOR通路调节自噬,发挥细胞毒性作用。     

防己诺林碱诱导人乳腺癌细胞MDA-MB-231凋亡的作用机制

目的 探讨防己诺林碱(FAN)对三阴性乳腺癌(TNBC)的抗肿瘤机制.方法 体外细胞培养人乳腺癌细胞MDA-MB-231,Alamar-Blue法检测FAN对人乳腺癌细胞MDA-MB-231的半抑制浓度(IC50);6孔板检测细胞迁移情况;细胞流式技术检测细胞凋亡情况;Western Blot检测磷脂酰肌醇-3羟基激酶(PI3K)、蛋白激酶B(AKT)、哺乳类动物雷帕霉素靶蛋白(mTOR)及磷酸化PI3K、AKT、mTOR蛋白表达.结果 FAN可抑制人乳腺癌细胞MDA-MB-231的活力(IC50为6.25μmol/L),抑制人乳腺癌细胞MDA-MB-231的迁移能力,且随着FAN浓度升高,抑制作用明显.FAN可以诱导人乳腺癌细胞MDA-MB-231凋亡,且随着FAN浓度升高,细胞凋亡率增高,同时FAN还可以下调PI3K、AKT、mTOR及磷酸化PI3K、AKT、mTOR蛋白的表达,随药物浓度的升高,其蛋白表达降低.结论 FAN可通过下调TNBC MDA-MB-231细胞凋亡PI3K/AKT/mTOR信号通路,抑制TNBC细胞的增殖、迁移,诱导细胞凋亡,可能具有抗肿瘤作用.     

顺铂通过抑制PI3K/AKT/mTOR信号通路诱导子宫内膜癌Ishikawa细胞自噬

目的：探讨顺铂对子宫内膜癌Ishikawa细胞自噬的影响,并初步探讨PI3K/AKT/mTOR信号通路在其中的作用。方法：透射电镜观察自噬泡形成,免疫荧光检测微管相关蛋白1轻链3融合蛋白II（microtubule-associated protein 1 light chain 3II,LC3II） 的荧光聚集情况。采用Westerblot检测mTOR通路中的PI3K、AKT及mTOR蛋白的表达。结果：顺铂（20μg/mL）能诱导Ishikawa细胞发生自噬,其中24h组明显高于12h组（P<0.05）;与对照组（20μg/mL-0h组）相比较,自噬相关蛋白-LC3的表达随着时间延长表达增加（P<0.05）。磷酸化AKT1、磷酸化mTOR及PI3Kp85蛋白表达水平随着时间延长表达下降。胰岛素样生长因子-1（insulin-like growth factors-1,IGF-1）与顺铂共培养组自噬小体及LC3蛋白表达少于顺铂组,但高于对照组。结论：顺铂可能通过抑制PI3K/AKT/mTOR信号通路,从而诱导子宫内膜癌细胞发生自噬。     

PI3K/AKT信号通路相关蛋白在乳腺癌中的表达及其临床意义

目的：研究PI3K/AKT信号转导通路中PTEN、PI3K、AKT蛋白在乳腺癌中的表达及其与疾病发生发展、预后的关系。方法用免疫组化SP法检测45例乳腺癌患者病理组织（观察组）和其中15例患者癌旁正常组织（对照组）中PTEN、PI3K、AKT表达情况,采用单因素回归分析对PTEN、PI3K、AKT蛋白在乳腺癌组织中阳性表达的相关因素进行分析。结果 PI3K、AKT在乳腺癌中的表达率分别为73.3%、75.5%,高于癌旁正常乳腺组织的33.3%、40%,差异具有统计学意义（P﹤0.05）;PTEN在乳腺癌中表达率为22.2%,低于癌旁正常乳腺组织的53.3%,但差异无统计学意义（P﹥0.05）;单因素回归分析结果显示,患者发病年龄对PTEN、PI3K、AKT在乳腺癌组织中阳性表达无关（P﹥0.05）;组织学分级、临床分期、存在淋巴结转移是PTEN、PI3K、AKT在乳腺癌组织中的阳性表达的相关因素（P﹤0.05）。结论 PI3K/AKT信号通路可能参与了乳腺癌的发生与发展,PTEN蛋白表达缺失导致AKT、PI3K蛋白的过度表达,PI3K、PTEN、AKT蛋白表达的检测可能有助于预测乳腺癌的预后。     

塞来昔布联合雷帕霉素对胃癌BGC823细胞的抗肿瘤作用及其机制

目的:研究塞来昔布增强胃癌BGC823细胞对雷帕霉素的敏感性,探讨PI3 K/Akt信号通路在塞来昔布增强胃癌BGC823细胞对雷帕霉素敏感性中的作用.方法:MTT法检测细胞对药物敏感性.Western blot法检测Akt和p-Akt蛋白表达.结果:100nmol/L雷帕霉素作用于BGC823胃癌细胞72h后,细胞存活抑制率不足30％.雷帕霉素可活化PI3K/Akt通路,PI3K抑制剂LY294002(25 μmol/L)预处理细胞1h后再予雷帕霉素作用72h,与单药雷帕霉素组相比,细胞存活率明显降低[(54.2±1.4)％和(83.6±2.3)％,P＜0.05].塞来昔布(40μmol/L)可明显抑制雷帕霉素引起的p-Akt活化,进而增强胃癌BGC823细胞对雷帕霉素的敏感性,细胞存活率从(81.9±2.3)％降至(51.5±4.4)％(P＜0.05).结论:塞来昔布通过抑制雷帕霉素诱导的PI3K/Akt活化,增强胃癌BGC823细胞对雷帕霉素的敏感性.     

siRNA靶向沉默MALAT-1对鼻咽癌细胞增殖、凋亡及PI3K/AKT通路的影响

目的:探究siRNA靶向沉默MALAT-1对鼻咽癌细胞增殖、凋亡及PI3K/AKT通路的影响。方法:分别以10、20、30、40、50 nmol/L浓度的siRNA靶向沉默体外培养的人鼻咽癌细胞株CNE的基因MALAT-1,以实时荧光定量（qRT-PCR）分别在24、48 h后检测MALAT-1 mRNA表达水平,筛选合适的siRNA作用浓度和时间。将CNE细胞分为三组:空白对照组、siRNA阴性对照组和siRNA组,siRNA处理细胞后,采用CCK-8法检测细胞增殖情况,采用流式细胞技术检测细胞凋亡情况,Western blot 检测各组细胞凋亡相关蛋白（Bcl-2、Bax、caspase-3）及PI3K/AKT通路蛋白（PI3K、ATK、p-AKT）表达情况。结果:选定30 nmol/L浓度的siRNA作用于CNE细胞48 h;siRNA处理细胞后,与空白对照组相比,siRNA组细胞增殖率明显降低,凋亡率明显升高,Bax、caspase-3蛋白表达明显升高,Bcl-2、PI3K、p-AKT蛋白表达明显降低,差异均有统计学意义（P＜0.05）;AKT蛋白表达无明显变化,差异无统计学意义（P＞0.05）。siRNA阴性对照组各指标均无明显变化,差异无统计学意义（P＞0.05）。结论:siRNA可靶向沉默MALAT-1,抑制鼻咽癌细胞增殖,促进其凋亡,可能是通过抑制PI3K/AKT通路实现的。     

雷帕霉素对肺癌细胞mTOR信号通路相关蛋白表达的作用

目的探讨mTOR信号通路的功能状态与肺癌对雷帕霉素敏感度的关系。方法Western blot检测mTOR信号通路中AKT、S6K1、eIF4E、4E-BP1、P-S6K1蛋白在4种人肺癌细胞株的表达;MTT法检测雷帕霉素对肺癌细胞增殖的抑制情况,将肺癌细胞分为雷帕霉素敏感组和不敏感组,找出与敏感度相关的差异蛋白,用En Vision法检测患者肺癌组织中差异蛋白的表达。结果AKT、S6K1、eIF4E、4E-BP1蛋白在4种肺癌细胞株中均有表达。而P-S6K1在不敏感株中未检测到, 在敏感株中呈高表达,为雷帕霉素差异蛋白。P-S6K1在正常肺组织中的阳性表达率为15％（3/20例),在肺癌组织中的阳性表达率为62%(62/100例),其中在小细胞肺癌组织中的阳性表达率(81.0%,17/21例)高于非小细胞肺癌组织（59%,45/79例)。结论在mTOR信号通路相关蛋白中,仅P-S6K1在一定程度上可预测肺癌细胞株对雷帕霉素的敏感度,为一种mTOR靶向抑制剂——雷帕霉素治疗肺癌的差异蛋白。P-S6K1在小细胞肺癌中表达较非小细胞肺癌高,提示在P-S6K1表达率高的小细胞未分化肺癌中应用mTOR靶向抑制剂——雷帕霉素的疗效可能更佳。     

Rapamycin induces p53-independent apoptosis through the mitochondrial pathway in non-small cell lung cancer cells

The mammalian target of rapamycin (mTOR) is a key kinase acting downstream of growth factor receptor PI3K and AKT signaling, leading to processes resulting in increased cell size and proliferation through translation control. Rapamycin, a specific inhibitor of mTOR, results predominately in G1 cell cycle arrest through translation control and occasionally, cell type-dependent apoptosis by an unknown mechanism. In this study, we investigated the effect and mechanism of action of rapamycin on non-small cell lung cancer (NSCLC) cell lines with p53 mutations. Cell proliferation was evaluated by modified MTT assay. The apoptotic effect of rapamycin was measured by caspase-3 activation and flow cytometric analysis of Annexin V binding. The expression of Bcl-2 and the release of cytochrome?c from mitochondria were evaluated by western blotting. We found that rapamycin induced apoptosis in NSCLC cell lines with p53 mutations. Western blot analysis demonstrated that rapamycin downregulates the expression levels of Bcl-2, which leads to increased cytochrome c release from mitochondria and subsequent activation of caspase cascades. These findings suggest that rapamycin induces p53-independent apoptosis through downregulation of Bcl-2 and the mitochondrial pathway in NSCLC cell lines as a novel antitumor mechanism.     

Combination effects of paclitaxel with signaling inhibitors in endometrial cancer cells

This study was conducted to evaluate and compare molecular and cellular effects of paclitaxel in combination with epidermoid growth factor receptor (EGFR) or/and mammalian target of rapamycin( mTOR) inhibitors with two endometrial cancer lines HEC-1A and Ishikawa. Treatment was with the EGFR inhibitor RG14620, the mTOR inhibitor rapamycin, and the conventional cytotoxic drug paclitaxel, alone or in combination. The 50% inhibitory concentration (IC50) and cell viability were determined by the MTT assay. Multiple drug effect/ combination indexes (CI) analysis was applied to assess interactions between paclitaxel and the two inhibitors. Apoptosis and cell cycling were evaluated by flow cytometry analysis. Western blotting was performed to evaluate the related protein alteration in PI3K/AKT signaling pathway. RG14620, rapamycin and paclitaxel showed obvious dose-dependent growth inhibition with time. The IC50 of paclitaxel at 24 hours decreased significantly when pretreated with low doses of RG14620 and Rapamycin alone or in combination. Moreover, combination index (CI) of paclitaxel with each inhibitor was larger than 1, indicating a synergistic effect between pairs of drugs in these two cell lines. FACS analysis showed the cell apoptosis rate increased with a synergistic effect. On Western blotting, activation of PI3K/AKT pathway was detected in both two cell lines in the control case. When paclitaxel was used as a single-agent or in combinations, the protein expression of PI3K/AKT pathway totally abated, especially in HEC-1A cells, suggesting a role in chemoresistance. The combination of three drugs induced the greatest over-expression of caspase-3. Combining targeted inhibitors with cytotoxic chemotherapy appears to be a promising strategy for the effective treatment of endometrial cancer which merits further clinical investigation.     

国产雷帕霉素对人淋巴瘤细胞Raji增殖的影响

目的探讨国产雷帕霉素（宜欣可）对人淋巴瘤细胞株Raji细胞体外生长及对mTOR/p 70S6K信号通路的影响。方法MTT法检测不同浓度（0、1、5、10、20、40、50、100 nmol/L）国产雷帕霉素作用不同时间（24、48、72 h）对Raji 细胞增殖的影响。光学显微镜观察Raji细胞形态学变化。流式细胞仪测定国产雷帕霉素对Raji细胞周期分布和凋亡的影响。Western blot 方法检测国产雷帕霉素处理前后对Raji 细胞mTOR、p70S6K、p-p70S6K蛋白的影响。结果国产雷帕霉素对Raji细胞增殖有明显的抑制作用（不同浓度P<0.01或P<0.05）,呈现明显的剂量-效应和时间-效应依赖关系。国产雷帕霉素明显抑制Raji细胞周期发展（P<0.05）,但没有发生明显的凋亡（P>0.05）。0、10、50、100 nmol/L国产雷帕霉作用于Raji细胞的mTOR、p-p70S6K,其蛋白量随药物浓度增大而降低（P<0.05）,p70S6K随药物浓度增大而升高（P<0.05）。结论人淋巴瘤细胞株Raji中存在mTOR/p70S6K信号通路激活状态,宜欣可可抑制该通路激活并通过阻滞细胞周期发展抑制Raji细胞增殖。     

PI3K/Akt/mdm2信号通路活化对胃癌细胞阿霉素敏感性的影响

目的 研究PI3K/Akt/mdm2信号通路活化对胃癌细胞阿霉素(DOX)敏感性的影响.方法 分别用DOX和PI3K特异性抑制剂wortmannin处理胃癌细胞株SGC7901,采用流式细胞仪检测肿瘤细胞的凋亡,免疫沉淀法检测PI3K活性,Western blot法检测PI3K-p85、phospho-Akt(S473)、phospho-mdm2(S166)、Akt和p53的表达.结果 DOX能诱导胃癌细胞SGC7901凋亡,且凋亡率与作用时间密切相关,联合应用wortmannin后,可促进胃癌细胞凋亡.DOX作用SGC7901细胞3、6、12和24 h后, PI3K活性逐渐增强,分别为(8.4±1.7)%、(12.7±2.1)%、(17.4±3.2)%和(16.8±2.4)%;同时,还促进Akt、mdm2磷酸化和p53表达.wortmannin可以抑制mdm2磷酸化,进一步增强p53的表达.结论 DOX可以诱导PI3K/Akt通路异常激活,并通过促进mdm2磷酸化降低胃癌细胞化疗敏感性.     

雷帕霉素联合紫杉醇对SGC-7901增殖影响的研究

目的：研究雷帕霉素联合紫杉醇对人胃癌SGC-7901细胞增殖和凋亡的影响。方法：MTT法检测经雷帕霉素、紫杉醇和雷帕霉素＋紫杉醇作用后人胃癌SGC-7901细胞的增殖抑制率,流式细胞术检测细胞凋亡率,蛋白质印迹法检测缺氧诱导因子-la（hypoxia-inducible{actor-1alpha,HIF-1α）及血管内皮生长因子（vascularendothelialgrowthfactor,VEGF）蛋白表达,两因素析因设计方差分析法进行统计分析。结果：雷帕霉素、紫杉醇及雷帕霉素联合紫杉醇处理SGC-7901细胞后细胞增殖抑制率分别为（25．43±1．98）％、（27．28±3．34）％和（53．64±1．99）％,雷帕霉素或紫杉醇单独作用均可抑制细胞增殖,联合作用对细胞增殖抑制率影响极显著,F-57．471,P〈0．001;两药联合指数〉1．15,雷帕霉素和紫杉醇具有协同作用。雷帕霉素、紫杉醇及雷帕霉素联合紫杉醇处理SGC-7901细胞后细胞凋亡率分别为（16．25±1．86）％、（21．80±3．12）％和（38．60±3．78）％,雷帕霉素或紫杉醇单独作用均可诱导细胞凋亡,两药联用细胞凋亡率显著增加,P=O．0163;雷帕霉素和紫杉醇具有协同诱导SGC-7901细胞凋亡作用。紫杉醇处理细胞后,HIF-1α及VEGF蛋白相对表达量分别为0．598±0．089和0．4204±0．091,VEGF蛋白表达下降,P=0．001;而HIF_1a蛋白表达无明显变化,P=0．434。雷帕霉素处理细胞后,HIF-1d及VEGF蛋白相对表达量分别为0．416±0．034和0．376土0．022,表达均显著下降,P值分别为0．016和0．001;而两药联合处理细胞后,HIF-1α及VEGF蛋白相对表达分别为0．209±0．027和0．156±0．015,均显著降低,F值分别为18．322和25．525,P值均为0．001。2种药物对SGC-7901细胞HIF-1aTYcVEGF蛋白表达抑制起到了显著的协同作用。结论：雷帕霉素联合紫杉醇可显著抑制人胃癌SGC-7901细胞增殖,诱导凋亡,2种药物具有协同抗肿瘤作用。     

Activation of mammalian target of rapamycin signaling pathway contributes to tumor cell survival in anaplastic lymphoma kinase-positive anaplastic large cell lymphoma

Anaplastic lymphoma kinase (ALK)-positive anaplastic large cell lymphoma (ALCL) frequently carries the t(2;5)(p23;q35) resulting in aberrant expression of chimeric nucleophosmin-ALK. Previously, nucleophosmin-ALK has been shown to activate phosphatidylinositol 3-kinase (PI3K) and its downstream effector, the serine/threonine kinase AKT. In this study, we hypothesized that the mammalian target of rapamycin (mTOR) pathway, which functions downstream of AKT, mediates the oncogenic effects of activated PI3K/AKT in ALK+ ALCL. Here, we provide evidence that mTOR signaling phosphoproteins, including mTOR, eukaryotic initiation factor 4E-binding protein-1, p70S6K, and ribosomal protein S6, are highly phosphorylated in ALK+ ALCL cell lines and tumors. We also show that AKT activation contributes to mTOR phosphorylation, at least in part, as forced expression of constitutively active AKT by myristoylated AKT adenovirus results in increased phosphorylation of mTOR and its downstream effectors. Conversely, inhibition of AKT expression or activity results in decreased mTOR phosphorylation. In addition, pharmacologic inhibition of PI3K/AKT down-regulates the activation of the mTOR signaling pathway. We also show that inhibition of mTOR with rapamycin, as well as silencing mTOR gene product expression using mTOR-specific small interfering RNA, decreased phosphorylation of mTOR signaling proteins and induced cell cycle arrest and apoptosis in ALK+ ALCL cells. Cell cycle arrest was associated with modulation of G(1)-S-phase regulators, including the cyclin-dependent kinase inhibitors p21(waf1) and p27(kip1). Apoptosis following inhibition of mTOR expression or function was associated with down-regulation of antiapoptotic proteins, including c-FLIP, MCL-1, and BCL-2. These findings suggest that the mTOR pathway contributes to nucleophosmin-ALK/PI3K/AKT-mediated tumorigenesis and that inhibition of mTOR represents a potential therapeutic strategy in ALK+ ALCL.     

The PI3K/AKT/mTOR Signaling Pathway: Implications in the Treatment of Breast Cancer

Epidemiologic and experimental studies support a key role of the phosphatidyl inositol 3-kinase/AKT/mammalian target of rapamycin (PI3K/AKT/mTOR) pathway in the biology of human cancers. Alterations resulting in activation of PI3K/Akt/mTOR signaling are perhaps the most frequent events observed in solid tumors, including breast cancer, and contribute to neoplastic transformation. The PI3K/mTOR pathway can be activated by overproduction of growth factors or chemokines, loss of phosphatase and tensin homolog (PTEN) expression, or by mutations in growth factor receptors Ras, PTEN, or PI3K itself. Activation of this pathway contributes to cell cycle proliferation, growth, cell cycle entry, survival, cell motility, protein synthesis, and glucose metabolism, all important aspects of tumorigenesis. The most common genetic aberrations in breast cancer are activating somatic missense mutations in the gene encoding the p110a (PIK3CA) subunit of PI3K. The PTEN gene is often hypermethylated or decreased in expression, through as yet unclear mechanisms, in breast cancer. Studies have shown that PI3K/PTEN/AKT pathway modulation is implicated in HER2/neu-tumorigenesis and in response to the HER2-targeting antibody trastuzumab. Components of the pathway are regulated by feed-back and cross-talk to other signaling cascades and appear to be implicated with drug resistance. Over the past few years, a number of components of this signaling cascade have been the subject of intense drug-discovery activities. Rapamycin analogs have already been shown to have antitumor efficacy in some tumor types. Newer-generation PI3K, AKT, and mTOR inhibitors have shown significant promise preclinically and are now in clinical trials. This article summarizes the progress made in the elucidation of the pathway, clinical implications in pathology of breast cancer, and reviews novel drugs targeting this pathway for cancer treatment, particularly inhibitors of PI3K, AKT, and mTOR, currently undergoing clinical trials. Potential combination strategies, safety concerns, and resistance mechanisms for this new generation of anticancer agents are also discussed.     

自噬对宫颈癌细胞增殖和迁移能力的影响

目的 观察自噬对宫颈癌细胞增殖迁移能力的影响,并探讨其可能机制。方法 采用不同浓度雷帕霉素诱导人宫颈癌HeLa细胞,吖啶橙染色观察自噬小体的形成,Western blot检测自噬相关基因LC3B以及PI3K/Akt/mTOR通路蛋白的表达情况,采用RTCA仪器实时检测细胞的增殖能力,Transwell小室检测细胞的迁移能力。应用自噬抑制剂3-methyladenine(3-MA)阻断宫颈癌细胞自噬后,采用RTCA仪器实时检测细胞的增殖能力,Transwell小室检测细胞的迁移能力。构建带有绿色荧光蛋白的LC3B质粒,转入HeLa细胞,通过G418药物筛选转染阳性细胞,荧光显微镜观察LC3B的细胞定位,Western blot检测LC3B表达。RTCA仪器实时检测野生型和LC3B过表达HeLa细胞的增殖能力,Western blot检测PI3K/Akt/mTOR通路蛋白的表达。结果 雷帕霉素诱导后,宫颈癌HeLa细胞自噬水平增高,增殖和迁移能力有所下降;PI3K/Akt/mTOR通路蛋白表达改变(P＜0.05)。自噬抑制剂3-MA诱导HeLa细胞增殖和迁移水平下降(P＜0.05)。荧光显微镜和Western blot结果显示构建的LC3质粒成功转入Hela细胞中并且能够抑制宫颈癌细胞的增殖(P＜0.05)。结论 在一定范围内,随着自噬水平的升高,HeLa细胞增殖和迁移能力降低,可能是通过PI3K/Akt/mTOR信号通路发挥作用。通过基因靶向扰乱自噬关键基因(如LC3等)而改变宫颈癌细胞自噬水平可能为宫颈癌的治疗带来新策略。