EYA1 通过调控PTEN/PI3K/AKT信号通路抑制胃癌SGC-7901 细胞的恶性生物学行为

[摘要] 目的:探讨EYA1(eyes absent 1)通过调控PTEN/PI3K/AKT信号通路抑制胃癌SGC-7901细胞的恶性进展及其相关机制。方法:收集2016年6月至2018年6月陆军军医大学附属西南医院全军普通外科中心29例胃癌组织及其癌旁组织标本,采用Wb和qPCR实验检测胃癌组织和癌旁组织中EYA1 mRNA和蛋白的表达水平。人胃癌细胞株SGC-7901培养完成后,采用过表达EYA1质粒或siRNA干扰质粒转染胃癌SGC-7901细胞;分别采用MTT、流式细胞术、划痕愈合和Transwell实验检测胃癌SGC-7901细胞的增殖、凋亡、迁移和侵袭能力。结果:胃癌组织中EYA1 mRNA 和蛋白表达水平较癌旁组织均明显降低（P<0.01）;过表达EYA1可明显提高SGC-7901 细胞的增殖、迁移和侵袭能力（均P<0.05）、抑制细胞凋亡（P<0.05）。过表达EYA1 可明显促进PTEN的表达、抑制PI3K/AKT通路的激活（均P<0.05或P<0.01）;但在PTEN干扰后以上作用均受到了明显抑制（均P<0.05或P<0.01）。结论:EYA1可通过促进PTEN的表达抑制PI3K/AKT信号通路,从而抑制胃癌SGC-7901细胞的恶性生物学行为。     

Increased activation of PI3K/AKT signaling pathway is associated with cholangiocarcinoma metastasis and PI3K/mTOR inhibition presents a possible therapeutic strategy

Phosphatidylinositol 3-kinase (PI3K) signaling plays a critical role in cholangiocarcinoma (CCA), as well as anti-cancer drug resistance and autophagy, the type II program cell death regulation. In this work, we aimed to: (1) determine the expression levels of several key components of PI3K signaling and (2) evaluate whether NVP-BEZ235, a novel dual PI3K/mTOR inhibitor, could inhibit CCA cell growth. Immunohistochemistry for p85α, p110α, AKT, p-AKT (T308), mTOR, p-mTOR (S2448), GSK-3β, p-GSK-3β (S9), PTEN, and p-PTEN (S380, T382/383) was performed in 30 CCA patients. Western blotting was used to analyze PTEN and p-PTEN expression in the cell lines (KKU-OCA17, KKU-100, KKU-M055, KKU-M139, KKU-M156, KKU-M213, and KKU-M214). The effects of NVP-BEZ235 on CCA cells were evaluated using a growth inhibition assay, flow cytometer and migration assay. Increased activation of PI3K/AKT signaling was reproducibly observed in the CCA tissues. The expression of p85α, mTOR, and GSK-3β was significantly correlated with metastasis. Interestingly, PTEN suppression by loss of expression or inactivation by phosphorylation was observed in the majority of patients. Furthermore, NVP-BEZ235 effectively inhibited CCA cell growth and migration through reduced AKT and mTOR phosphorylation and significantly induced G1 arrest without apoptosis induction, although increase autophagy response was observed. In conclusion, the constitutive activation of PI3K/AKT pathway in CCA is mainly due to PTEN inactivation by either loss of expression or phosphorylation along with an increased expression in its pathway components heralding a poor prognosis for CCA patients. This work also indicates that inhibition of PI3K and mTOR activity by the inhibitor NVP-BEZ235 has anti-cancer activity against CCA cells which might be further tested for CCA treatment.     

PI3K、AKT、PTEN在脑胶质瘤中的表达及其临床意义

背景与目的：PI3K/AKT信号通路可能在人脑恶性胶质瘤的发生发展过程中起重要作用。本研究探讨人脑胶质瘤中PI3K/AKT通路相关蛋白PI3K、AKT、PTEN在脑胶质瘤中的表达及其与胶质瘤病理分级之间的关系。方法：采用免疫组化Envision二步法检测PI3K、AKT、PTEN蛋白在42例不同级别脑胶质瘤、10例正常脑组织中的表达,计算阳性细胞百分率,用统计学方法分析人脑胶质瘤中PI3K、AKT、PTEN蛋白表达之间的相关性及其三者与胶质瘤不同分级之间的关系。结果：PI3K在人脑胶质瘤组织的阳性表达率是80.95%,而正常脑组织中表达率为20.00%,两者间差异有统计学意义（P〈0.05）;PI3K蛋白在低级别胶质瘤和高级别胶质瘤中的阳性率分别是66.67%、95.24%,两者之间差异有统计学意义（P〈0.05）。胶质瘤组织与正常脑组织中AKT蛋白阳性率分别是85.71%与30.00%,两者差异有统计学意义（P〈0.05）;AKT蛋白在低级别胶质瘤和高级别胶质瘤中的阳性率分别是76.19%与95.24%,两者之间差异有统计学意义（P〈0.05）;胶质瘤组织与正常脑组织中PTEN蛋白阳性率分别是45.24%、100%,两者差异有统计学意义（P〈0.01）;PTEN蛋白在低级别胶质瘤中的阳性率52.38%,而高级别胶质瘤表达率为38.10%,两者之间差异有显著性（P〈0.05）;PTEN与PI3K、AKT蛋白在脑胶质瘤中的表达分别呈负相关（P〈0.01）;PI3K与AKT蛋白的阳性表达呈正相关（P〈0.01）。结论：（1）在人脑胶质瘤组织中PI3K、AKT蛋白表达明显增高,且PI3K、AKT蛋白阳性表达与胶质瘤恶性程度正相关,说明了PI3K/AKT信号通路在胶质瘤的恶性转化中发挥着重要作用。（2）胶质瘤组织中PTEN蛋白的阳性表达率明显低于其在正常脑组织中的表达,与胶质瘤的恶性程度负相关,提示了PTEN蛋白的表达下降或缺失导致其抑癌功能减弱甚至丧失,其与胶质瘤的发生发展密切相关。（3）在人脑胶质瘤组织中,PTEN与PI3K、AKT蛋白表达呈负相关,揭示了在胶质瘤的发生发展中PTEN与PI3K、AKT的作用可能互相拮抗,PTEN蛋白的表达下降或缺失与PI3K、AKT的过度表达可能共同促进了胶质瘤的恶性进展。     

miR-429通过下调PTEN并激活PI3K/AKT信号通路促进胰腺癌PANC-1细胞对卡培他滨耐药

目的:探讨miR-429 靶向PTEN并通过PI3K/AKT信号通路调控胰腺癌PANC-1 细胞对卡培他滨的耐药性及其作用机制。方法：建立胰腺癌卡培他滨耐药细胞株PANC-1/CAP后,采用qRT-PCR和Western blotting 实验检测miR-429 和PTEN在胰腺癌细胞中的表达情况,平板克隆形成实验、CCK-8 法和Annexin V-FITC/PI 双染流式细胞术检测敲降miR-429 对胰腺癌卡培他滨耐药细胞株PANC-1/CAP 细胞增殖、凋亡和卡培他滨耐药性的影响,双荧光素酶报告基因验证miR-429 与PTEN 的靶向关系,Western blotting 实验进一步检测miR-429 对PTEN-PI3K/AKT信号通路的调控作用。结果：miR-429 在胰腺癌PANC-1 细胞和PANC-1/CAP细胞中的表达水平高于人胰腺导管上皮细胞（HPDE6-C7）（P<0.05 或P<0.01）,敲降miR-429 可显著抑制PANC-1/CAP细胞增殖活力、促进细胞凋亡及下调细胞卡培他滨耐药性,且双荧光素酶报告基因证实miR-429 靶向作用PTEN并下调其表达水平（P<0.05 或P<0.01）;敲降miR-429 可通过靶向上调PTEN并阻断PI3K/AKT信号通路进而显著抑制PANC-1/CAP细胞增殖活力,从而下调PANC-1/CAP细胞对卡培他滨的耐药性（P<0.05 或P<0.01）。结论：miR-429/PTEN-PI3K、AKT信号通路与胰腺癌卡培他滨耐药性存在调控关系,且敲降miR-429 可逆转PANC-1/CAP对卡培他滨的耐药性。     

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.     

胃癌细胞SGC7901凋亡的PI3K/Akt通路介导作用及雷帕霉素的作用机制分析

目的：分析雷帕霉素对胃癌细胞中PI3K/Akt蛋白表达的影响作用,以为临床治疗提供参考。方法将生长状态良好的胃癌细胞SGC7901随机分为4组：对照组,雷帕霉素低剂量组、中剂量、高剂量组（n=8）。采用DAPI染色法分析各组细胞的凋亡情况;采用免疫印迹法和Real-time PCR检测PI3K/AKT信号通路中相关蛋白PI3K、AKT、mTOR蛋白及mRNA的表达。结果雷帕霉素低、中、高剂量组均可抑制细胞的增殖,差异具有统计学意义（P﹤0.05）;雷帕霉素下调了胃癌细胞中PI3K、AKT、mTOR蛋白及mRNA的表达,且与对照组比较,差异均有统计学意义（P﹤0.05）。结论雷帕霉素主要通过抑制PI3K、AKT及mTOR的过表达发挥肿瘤抑制作用。     

miR-214通过PTEN调控AKT信号通路抑制鼻咽癌细胞凋亡CSCD

目的探讨miR-214通过PTEN调控下游AKT信号通路激活对鼻咽癌细胞凋亡的影响。方法miR-214抑制剂转染鼻咽癌5-8F和6-10B细胞。MTT法评估细胞增殖情况。Annexin-V/PI染色法检测两种鼻咽癌细胞凋亡情况。Western blot和real-time PCR检测miR-214抑制剂对PTEN基因转录和蛋白表达以及对AKT信号通路和凋亡相关蛋白表达水平的影响。检测shRNA沉默PTEN基因转录和蛋白表达后,miR-214抑制剂对鼻咽癌细胞凋亡影响。结果miR-214抑制剂可抑制鼻咽癌细胞生长,诱导5-8F和6-10B细胞凋亡。miR-214通过靶向3'-UTR区域调控PTEN基因转录和蛋白表达。抑制miR-214可促进PTEN的表达,抑制AKT信号通路激活,进而调控下游细胞周期和凋亡相关蛋白表达。沉默PTEN基因转录和蛋白表达可逆转miR-214抑制剂对鼻咽癌细胞AKT信号通路活性和凋亡的影响。结论miR-214可通过直接靶向PTEN基因转录促进AKT信号通路激活抑制鼻咽癌细胞凋亡。     

细胞角蛋白13通过PTEN抑制PI3K/AKT/mTOR通路增强鼻咽癌HNE1细胞放疗敏感性

目的:探讨细胞角蛋白13(cytokeratin13,CK13)对鼻咽癌HNE1细胞放疗敏感性的影响及其作用机制.方法:将HNE1细胞分为对照组、anti-CK13#a组及anti-CK13#b组(敲减CK13)、对照组+西罗莫司处理组(100nmol/L的西罗莫司处理1 h)、anti-CK13#a+西罗莫司处理组(...     

TRPC3在胰腺癌细胞系中的表达及功能

目的:研究TRPC3在胰腺癌（pancreatic cancer,PC）细胞系中的表达及对细胞增殖和凋亡的影响。方法:采用qRT-PCR和Western blot检测正常和PC细胞系中TRPC3表达;采用Western blot检测GdCl3和TRPC3 siRNA干预PC细胞系后TRPC3、PI3K、p-PI3K、AKT、p-AKT和PTEN蛋白表达;CCK-8法检测细胞增殖;DAPI染色法检测细胞形态学;Annexin V/PI双标法检测细胞凋亡;钙成像法检测细胞内［Ca2+］ i。结果:PC细胞系中TRPC3 mRNA和蛋白表达明显高于正常胰腺上皮细胞HDPE6-C7;与溶剂和转染阴性对照细胞比较,GdCl3和转染TRPC3 siRNA的Panc1、A8184和T3M4细胞核固缩数量明显增加,Annexin V/PI双阳性凋亡细胞比例明显增多,T3M4细胞的静息［Ca2+］i、达峰［Ca2+］i和恢复相［Ca2+］i浓度明显降低;A8184和T3M4细胞的p-PI3K、p-AKT和PTEN蛋白表达明显降低。结论:TRPC3在PC细胞系中表达上调,且TRPC3通过调节细胞Ca2+介导的PI3K/AKT信号通路从而影响PC细胞增殖和凋亡。     

Frequent activation of AKT2 and induction of apoptosis by inhibition of phosphoinositide-3-OH kinase/Akt pathway in human ovarian cancer

We previously demonstrated that AKT2, a member of protein kinase B family, is activated by a number of growth factors via Ras and PI 3-kinase signaling pathways. Here, we report the frequent activation of AKT2 in human primary ovarian cancer and induction of apoptosis by inhibition of phosphoinositide-3-OH kinase (PI 3-kinase)/Akt pathway. In vitro AKT2 kinase assay analyses in 91 ovarian cancer specimens revealed elevated levels of AKT2 activity (>3-fold) in 33 cases (36.3%). The majority of tumors displaying activated AKT2 were high grade and stages III and IV. Immunostaining and Western blot analyses using a phospho-ser-473 Akt antibody that detects the activated form of AKT2 (AKT2 phosphorylated at serine-474) confirmed the frequent activation of AKT2 in ovarian cancer specimens. Phosphorylated AKT2 in tumor specimens localized to the cell membrane and cytoplasm but not the nucleus. To address the mechanism of AKT2 activation, we measured in vitro PI 3-kinase activity in 43 ovarian cancer specimens, including the 33 cases displaying elevated AKT2 activation. High levels of PI 3-kinase activity were observed in 20 cases, 15 of which also exhibited AKT2 activation. The remaining five cases displayed elevated AKT1 activation. Among the cases with elevated AKT2, but not PI 3-kinase activity (18 cases), three showed down-regulation of PTEN protein expression. Inhibition of PI 3-kinase/AKT2 by wortmannin or LY294002 induces apoptosis in ovarian cancer cells exhibiting activation of the PI 3-kinase/AKT2 pathway. These findings demonstrate for the first time that activation of AKT2 is a common occurrence in human ovarian cancer and that PI 3-kinase/Akt pathway may be an important target for ovarian cancer intervention.     

An integrative genomic and proteomic analysis of PIK3CA, PTEN, and AKT mutations in breast cancer

Phosphatidylinositol 3-kinase (PI3K)/AKT pathway aberrations are common in cancer. By applying mass spectroscopy-based sequencing and reverse-phase protein arrays to 547 human breast cancers and 41 cell lines, we determined the subtype specificity and signaling effects of PIK3CA, AKT, and PTEN mutations and the effects of PIK3CA mutations on responsiveness to PI3K inhibition in vitro and on outcome after adjuvant tamoxifen. PIK3CA mutations were more common in hormone receptor-positive (34.5%) and HER2-positive (22.7%) than in basal-like tumors (8.3%). AKT1 (1.4%) and PTEN (2.3%) mutations were restricted to hormone receptor-positive cancers. Unlike AKT1 mutations that were absent from cell lines, PIK3CA (39%) and PTEN (20%) mutations were more common in cell lines than tumors, suggesting a selection for these but not AKT1 mutations during adaptation to culture. PIK3CA mutations did not have a significant effect on outcome after adjuvant tamoxifen therapy in 157 hormone receptor-positive breast cancer patients. PIK3CA mutations, in comparison with PTEN loss and AKT1 mutations, were associated with significantly less and inconsistent activation of AKT and of downstream PI3K/AKT signaling in tumors and cell lines. PTEN loss and PIK3CA mutation were frequently concordant, suggesting different contributions to pathophysiology. PTEN loss rendered cells significantly more sensitive to growth inhibition by the PI3K inhibitor LY294002 than did PIK3CA mutations. Thus, PI3K pathway aberrations likely play a distinct role in the pathogenesis of different breast cancer subtypes. The specific aberration present may have implications for the selection of PI3K-targeted therapies in hormone receptor-positive breast cancer.     

Mutational analysis of PTEN/PIK3CA/AKT pathway in oral squamous cell carcinoma

The phosphoinositide 3-kinase (PI3K)/v-akt murine thymoma (AKT) viral oncogene pathway is involved in regulating the signaling of multiple biological processes such as apoptosis, metabolism, cell proliferation, and cell growth. Mutations in the genes associated with the PI3K/AKT pathway including PI3K, AKT, RAS and PTEN, are infrequently found within head and neck squamous cell carcinoma and more specifically are rarely reported in oral squamous cell carcinoma (OSCC) cases. We aimed to investigate the frequency of mutations in AKT1, PTEN, PIK3CA, and RAS (K-RAS, N-RAS, H-RAS) genes in 37 cases of oral squamous cell carcinoma (OSCC). Mutational analysis of PTEN, RAS, PIK3CA and AKT genes was performed using chip-based matrix-assisted laser desorption time-of-flight (MALDI-TOF) mass spectrometry and by direct sequencing. The only gene mutated in our series was the PIK3CA. Missense mutations of the PIK3CA gene were found in 4 of our cases (10.8%); no correlation has been found with oral location, stage and survival. The absence of mutations in AKT1, PTEN, and RAS genes in the present study is in accordance with previous studies confirming that these genes are rarely mutated in OSCC. Our data confirm that PIK3CA is important to OSCC tumorigenesis and can contribute to oncogene activation of the PIK3CA/AKT pathway in OSCC. The knowledge of the PIK3CA's involvement in OSCC is important because a specific kinase inhibitor could be considered as a future therapeutic option for OSCC patients with PIK3CA mutations.     

miR-103 靶向PTEN并激活PI3K/AKT通路促进肺癌细胞A549 对达沙替尼耐药

[摘要] 目的：探讨miR-103 靶向PTEN并激活PI3K/AKT信号通路促进肺癌细胞对达沙替尼（dasatinib,DASA）耐药的机制。方法：收集2014 年4 月至2018 年1 月昆明医科大学第一附属医院胸外科收治的资料完整的肺癌DASA耐药组织和不耐药组织各35 例。采用qPCR实验检测miR-103 在肺癌DASA耐药组织和细胞中的表达水平,同时,采用CCK-8、Transwell 和Wb实验检测敲降miR-103 对A549/DASA细胞增殖、迁移和上皮间质转化（EMT）的影响,双荧光素酶报告基因验证miR-103 与PTEN的靶向关系。进一步采用CCK-8、Transwell 和Wb实验检测miR-103 通过PTEN-PI3K/AKT信号通路对A549/DASA细胞恶性生物学行为的影响。结果：miR-103 在肺癌DASA 耐药组织和A549/DASA 细胞中均高表达（均P<0.01）。敲降miR-103 可显著抑制A549/DASA细胞的增殖、迁移和EMT（P<0.05 或P<0.01）。此外,双荧光素酶报告基因证实miR-103 靶向作用PTEN并下调其表达水平（P<0.01）。进一步实验显示,过表达miR-103 通过靶向下调PTEN并激活PI3K/AKT信号通路进而显著促进A549/DASA细胞增殖、迁移和EMT（P<0.05 或P<0.01）,从而上调A549/DASA细胞对DASA的耐药性。结论：miR-103/PTEN/PI3K/AKT信号通路与肺癌DASA耐药性存在调控关系,敲降miR-103 可逆转A549/DASA对DASA耐药。     

Association of PTEN gene methylation with genetic alterations in the phosphatidylinositol 3-kinase/AKT signaling pathway in thyroid tumors

BACKGROUND: The phosphatidylinositol 3-kinase (PI3K)/AKT pathway plays an important role in thyroid tumorigenesis and progression. Genetic alterations, particularly PIK3CA amplification and mutations and ras mutations, are the major cause of aberrant activation of this pathway in thyroid tumors. Epigenetic silencing of the PTEN gene, a negative regulator of the PI3K/AKT pathway, also occurs in thyroid tumors, but its relationship with genetic alterations in this pathway is unclear. METHODS: By using quantitative methylation-specific polymerase chain reaction, the authors examined PTEN methylation and its relationship with genetic alterations in the PI3K/AKT pathway in various types of thyroid tumors. RESULTS: The authors found PTEN methylation to become progressively higher from benign thyroid adenoma to follicular thyroid cancer and to aggressive anaplastic thyroid cancer, which harbored activating genetic alterations in the PI3K/AKT pathway correspondingly with a progressively higher prevalence. The association of PTEN methylation was seen with both overall genetic alterations and individual genetic alterations, particularly PIK3CA alterations and ras mutations, in the PI3K/AKT pathway within each of the 3 types of thyroid tumors. In contrast, no such relationship was observed for the tumor suppressor gene RASSF1A. CONCLUSIONS: The authors found an interesting association of PTEN methylation with the activating genetic alterations in the PI3K/AKT pathway in thyroid tumors. This finding is consistent with a model in which aberrant methylation and hence silencing of the PTEN gene, which coexists with activating genetic alterations of the PI3K/AKT pathway, may enhance the signaling of this pathway aberrantly activated by genetic alterations and hence contribute to the progression of thyroid tumors. Cancer 2008.     

YTHDF2通过诱导IGFBP7的mRNA衰变激活PI3K/AKT信号转导通路促进胶质母细胞瘤进展的研究

背景与目的：N6-甲基腺苷（N6-methyladenosine,m6A）甲基化修饰识别蛋白YTHDF2被证实在癌症进展中扮演重要角色。探讨YTHDF2是否通过促进胰岛素样生长因子结合蛋白7(insulin-like growth factor binding protein 7,IGFBP7)的mRNA衰变,激活磷脂酰肌醇3-激酶（phosphoinositide 3-kinase,PI3K）-蛋白激酶B(protein kinase,AKT)信号转导通路,调控胶质母细胞瘤（glioblastoma,GBM）的细胞周期和凋亡。方法：采用实时荧光定量聚合酶链反应（realtime fluorescence quantitative polymerase chain reaction,RTFQ-PCR）检测YTHDF2和IGFBP7在GBM组织和细胞中的表达。通过流式细胞术检测细胞周期和凋亡率。采用蛋白质印迹法（Western blot）检测p-AKT、AKT、p-PI3K和PI3K蛋白表达。采用RNA免疫沉淀（RNA immunoprecipitation,RIP）实验和RNA稳定性实...     

Synergistic effects of Pten loss and WNT/CTNNB1 signaling pathway activation in ovarian granulosa cell tumor development and progression

The mechanisms of granulosa cell tumor (GCT) development may involve the dysregulation of signaling pathways downstream of follicle-stimulating hormone, including the phosphoinosite-3 kinase (PI3K)/AKT pathway. To test this hypothesis, a genetically engineered mouse model was created to derepress the PI3K/AKT pathway in granulosa cells by conditional targeting of the PI3K antagonist gene Pten (Pten(flox/flox);Amhr2(cre/+)). The majority of Pten(flox/flox);Amhr2(cre/+) mice featured no ovarian anomalies, but occasionally ( approximately 7%) developed aggressive, anaplastic GCT with pulmonary metastases. The expression of the PI3K/AKT downstream effector FOXO1 was abrogated in Pten(flox/flox);Amhr2(cre/+) GCT, indicating a mechanism by which GCT cells may increase proliferation and evade apoptosis. To relate these findings to spontaneously occurring GCT, analyses of PTEN and phospho-AKT expression were performed on human and equine tumors. Although PTEN loss was not detected, many GCT (2/5 human, 7/17 equine) featured abnormal nuclear or perinuclear localization of phospho-AKT, suggestive of altered PI3K/AKT activity. As inappropriate activation of WNT/CTNNB1 signaling causes late-onset GCT development and cross talk between the PI3K/AKT and WNT/CTNNB1 pathways has been reported, we tested whether these pathways could synergize in GCT. Activation of both the PI3K/AKT and WNT/CTNNB1 pathways in the granulosa cells of a mouse model (Pten(flox/flox);Ctnnb1(flox(ex3)/+);Amhr2(cre/+)) resulted in the development of GCT similar to those observed in Pten(flox/flox);Amhr2(cre/+) mice, but with 100% penetrance, perinatal onset, extremely rapid growth and the ability to spread by seeding into the abdominal cavity. These data indicate a synergistic effect of dysregulated PI3K/AKT and WNT/CTNNB1 signaling in the development and progression of GCT and provide the first animal models for metastatic GCT.     

Effect of BRAF-mediated PI3K/Akt/mTOR pathway on biological characteristics and chemosensitivity of NSCLC A549/DDP cells

The present study aimed to explore the biological characteristics of non-small cell lung cancer (NSCLC) cells and the mechanism of chemosensitivity through the role of the PI3K/Akt/mTOR signaling pathway mediated by BRAF gene silencing. Following cell transfection and grouping, an MTT assay detected the activity of NSCLC cells, a scratch wound test assessed the migration ability, flow cytometry using PI staining detected the cell cycle phase, TUNEL and flow cytometry through Annexin V-PI staining assessed the apoptosis, and colony formation was used to detect the sensitivity of lung cancer cells to cisplatin chemotherapy. Furthermore, the relative expression levels of BRAF, PTEN, PI3K, mTOR mRNA were assessed by RT-qPCR, and the protein expression levels of BRAF, PTEN, PI3K, phosphorylated (p)-PI3K, Akt, p-Akt, mTOR, p-mTOR, cisplatin resistance-related enzymes ERCC1 and BRCA1, apoptotic proteins Bax and Bcl-2 were assessed by western blotting. Compared with the control group and NC group, there were differences in decreased BRAF mRNA expression levels in the small interfering (si)BRAF group and siBRAF + IGF-1 group (both P<0.05). In addition, compared with the control group, the siBRAF, NVP-BEZ235 and siBRAF + NVP-BEZ235 groups had significant decreased cell viability at 2–6 days, decreased migration ability, shortened proportion of S-phase cells, increased proportion of G₁/G₀-phase cells, increased apoptosis rate, decreased number of colony-forming cells, decreased mRNA expression of PI3K, Akt and mTOR, increased PTEN mRNA expression, decreased protein expression levels of PI3K, p-PI3K, Akt, p-Akt, mTOR, p-mTOR, ERCC1, BRCA1 and Bcl-2, and increased protein expression levels of PTEN and Bax (all P<0.05); and more obvious trends were revealed in the siBRAF + NVP-BEZ235 group (all P<0.05); whereas opposite results were detected in the siBRAF + IGF-1 group when compared with the siBRAF group and NVP-BEZ235 group (all P<0.05). Silencing of BRAF gene expression to inhibit the activation of the PI3K/Akt/mTOR signaling pathway exerted a synergistic effect decreasing cell viability, inhibiting the cell cycle and migration, increasing the apoptosis rate, decreasing the number of colony-forming cells and increasing chemosensitivity of NSCLC. Activation of the PI3K/Akt/mTOR signaling pathway may reverse the role of silencing of BRAF gene expression, providing a potential approach for improving the chemosensitivity of NSCLC. The present study for the first time, to the best of our knowledge, clarified the possible mechanism of NSCLC cell biological characteristic changes and chemosensitivity from the perspective of BRAF gene silencing and PI3K/Akt/mTOR signaling pathway activation, providing a potential reference for suppressing tumor aggravation and improving the therapeutic outcomes of NSCLC at the genetic level.     

Downregulation of MicroRNA-147 Inhibits Cell Proliferation and Increases the Chemosensitivity of Gastric Cancer Cells to 5-Fluorouracil by Directly Targeting PTEN

Gastric cancer is the fourth most common malignancy and the third leading cause of cancer-related deaths worldwide. This study aimed to investigate the expression patterns, biological roles, and underlying mechanisms of microRNA-147 (miR-147) in gastric cancer. The present study demonstrated that miR-147 was significantly upregulated in gastric cancer tissues and cell lines. Downregulation of miR-147 decreased cell proliferation and enhanced the chemosensitivity of gastric cancer cells to 5-fluorouracil (5-FU) through the cell apoptosis pathway. In addition, phosphatase and tensin homolog (PTEN) was mechanically identified as the direct target of miR-147 in gastric cancer. PTEN knockdown reversed the effects of miR-147 downregulation on the proliferation, chemosensitivity, and 5-FU-induced apoptosis of gastric cancer cells. Moreover, miR-147 regulated the PI3K/AKT signaling pathway in gastric cancer by targeting PTEN. In conclusion, miR-147 suppressed the proliferation and enhanced the chemosensitivity of gastric cancer cells to 5-FU by promoting cell apoptosis through directly targeting PTEN and regulating the PI3K/AKT signaling pathway. This study provides important insight into the molecular mechanism that underlies the chemoresistance of gastric cancer cells. The results of this study could aid the development of a novel therapeutic strategy for gastric cancer.