Targeting the PI3K/AKT/mTOR pathway in biliary tract cancers: A review of current evidences and future perspectives

Biliary tract cancers (BTCs) are a group of invasive neoplasms, with increasing incidence and dismal prognosis. In advanced disease, the standard of care is represented by first-line chemotherapy with cisplatin and gemcitabine. In subsequent lines, no clear recommendations are currently available, highlighting the need for novel therapeutic approaches.The PI3K/AKT/mTOR pathway is a core regulator of cell metabolism, growth and survival, and is involved in BTCs carcinogenesis and progression. Mutations, gene copy number alterations and aberrant protein phosphorylation of PI3K, AKT, mTOR and PTEN have been thoroughly described in BTCs and correlate with poor survival outcomes.Several pre-clinical evidences state the efficacy of PI3K/AKT/mTOR pathway inhibitors in BTCs, both in vitro and in vivo. In the clinical setting, initial studies with rapamycin analogs have shown interesting activity with an acceptable toxicity profile. Novel strategies evaluating AKT and PI3K inhibitors have risen serious safety concerns, pointing out the need for improved patient selection and increased target specificity for the clinical development of these agents, both alone and in combination with chemotherapy.This review extensively describes the role of the PI3K/AKT/mTOR pathway in BTCs and examines the rationale of its targeting in these tumors, with particular focus on clinical activity, toxicities and perspectives on further development of PI3K/AKT/mTOR pathway inhibitors.     

Targeting autophagy in colorectal cancer: An update on pharmacological small-molecule compounds

Autophagy, an evolutionarily highly conserved cellular degradation process, plays the Janus role (either cytoprotective or death-promoting) in colorectal cancer, so the targeting of several key autophagic pathways with small-molecule compounds may be a new therapeutic strategy. In this review, we discuss autophagy-associated cell death pathways and key cytoprotective autophagy pathways in colorectal cancer. Moreover, we summarize a series of small-molecule compounds that have the potential to modulate autophagy-associated cell death or cytoprotective autophagy for therapeutic purposes. Taken together, these findings demonstrate the Janus role of autophagy in colorectal cancer, and shed new light on the exploitation of a growing number of small-molecule compounds to target autophagy in future cancer drug discovery.     

N-乙酰半胱氨酸对糖氧剥夺诱导星形胶质细胞损伤的抑制作用及机制研究

目的 探讨N-乙酰半胱氨酸（N-acetyl-L-cysteine,NAC）对糖氧剥夺（oxygen and glucose deprivation,OGD）诱导的星形胶质细胞损伤过程中AKT信号通路的影响及其意义。方法 以原代培养的星形胶质细胞建立OGD模型,并分为4组：对照组,OGD组,NAC组和NAC+AKT特异性抑制剂MK-2206组（NAC+MK-2206组）;细胞培养24 h后,采用噻唑蓝（MTT）法检测细胞存活率、流式细胞仪技术分析细胞凋亡比例,试剂盒检测细胞内SOD活性和丙二醛（MDA）含量,蛋白免疫印迹法检测细胞内AKT、磷酸化AKT（p-AKT）、mTORC1、磷酸化mTORC1（p-mTORC1）、胞浆型磷脂酶A2（cLPA2）、caspase3及Bcl-2的表达水平。结果 与OGD组相比,NAC组的细胞存活率,p-AKT、p-mTORC1及Bcl-2表达和SOD活性增加,细胞凋亡比例,cPLA2、caspase3表达,MDA含量降低。与NAC组相比,NAC+MK-2206组的细胞存活率,p-AKT、p-mTORC1及Bcl-2表达和SOD活性降低,细胞凋亡比例、cPLA2、MDA含量、caspase3表达增加。结论 NAC缓解OGD诱导AKT信号通路抑制作用,降低cPLA2诱导细胞凋亡作用。     

Endocytosis and Transport of Growth Factor Receptors in Peripheral Axon Regeneration: Novel Lessons from Neurons Expressing Lysine-Deficient FGF Receptor Type 1 in vitro

In the course of peripheral nerve regeneration, axons encounter different extracellular growth factors secreted by non-neuronal cells at the injury site and retrogradely transported after binding to neuronal membrane receptor tyrosine kinases. The present study reviews the role of receptor transport in peripheral axon outgrowth and provides novel data on trafficking of fibroblast growth factor receptor type 1 (FGFR1). Differences in receptor transport are determined by different numbers of lysine residues acting as ubiquitination sites in the intracellular receptor domain. We previously demonstrated that overexpression of mutant FGFR1-25R (25 out of 29 intracellular lysines replaced with arginine) results in enhanced receptor recycling as compared to wild-type FGFR1 followed by strong stimulation of elongative axon growth in vitro. Here, the effects of lysine-deficient FGFR1 (FGFR1-29R lacking all 29 cytoplasmic lysine residues) or of only 15 lysine mutations (FGFR1-15R) on axon outgrowth and concomitant changes in signal pathway activation were investigated by immunocytochemistry and morphometry of cultured primary neurons. Overexpression of FGFR1-15R in adult sensory neurons resulted in enhanced receptor recycling, which was accompanied by increased axon elongation without stimulating axon branching. By contrast, FGFR1-29R was neither endocytosed nor axon outgrowth affected. Although overexpression of FGFR1-15R or FGFR1-25Ra strongly promoted elongation, we did not detect increased signal pathway activation (ERK, AKT, PLC, or STAT3) in neurons expressing mutant FGFR1 as compared with wild-type neurons raising the possibility that other signaling pathways or signaling independent mechanisms may be involved in the axon outgrowth effects of recycled FGF receptors. Anat Rec, 302:1268–1275, 2019. © 2019 The Authors. The Anatomical Record published by Wiley Periodicals, Inc. on behalf of American Association of Anatomists.     

ARL4C stabilized by AKT/mTOR pathway promotes the invasion of PTEN-deficient primary human glioblastoma

Phosphatase and tensin homolog deleted on chromosome 10 (PTEN) deficiency in primary human glioblastoma (GBM) is associated with increased invasiveness and poor prognosis with unknown mechanisms. Therefore, how loss of PTEN promotes GBM progression remains to be elucidated. Herein, we identified that ADP-ribosylation factor like-4C (ARL4C) was highly expressed in PTEN-deficient human GBM cells and tissues. Mechanistically, loss of PTEN stabilized ARL4C protein due to AKT/mTOR pathway-mediated inhibition of ARL4C ubiquitination. Functionally, ARL4C enhanced the progression of GBM cells in vitro and in vivo. Moreover, microarray profiling and GST pull-down assay identified that ARL4C accelerated tumor progression via RAC1-mediated filopodium formation. Importantly, targeting PTEN potently inhibited GBM tumor progression in vitro and in vivo, whereas overexpression of ARL4C reversed the tumor progression impaired by PTEN overexpression. Clinically, analyses with patients' specimens validated a negative correlation between PTEN and ARL4C expression. Elevated ARL4C expression but PTEN deficiency in tumor was associated with poorer disease-free survival and overall survival of GBM patients. Taken together, ARL4C is critical for PTEN-deficient GBM progression and acts as a novel prognostic biomarker and a potential therapeutic candidate. Copyright © 2018 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.     

Interferon-γ upregulates Δ42PD1 expression on human monocytes via the PI3K/AKT pathway

BackgroundWe recently identified a novel alternatively spliced isoform of human programmed cell death 1 (PD-1), named Δ42PD1, which contains a 42-base-pair in-frame deletion compared with the full-length PD-1. Δ42PD1 is likely constitutively expressed on human monocytes and down-regulated in patients infected with human immunodeficiency virus type 1 (HIV-1). The mechanism underlying the regulation of Δ42PD-1 expression in monocytes remains unknown.MethodsBy flow cytometry, we investigated the effect of Interferon-gamma (INF-γ) on the expression of Δ42PD1 in primary human monocytes as well as monocytic cell lines THP-1 and U937 cells. In addition, signaling pathway inhibitors and Δ42PD1-specific blocking antibody were used to explore the pathway involved in INF-γ-induced Δ42PD1 upregulation, and to elucidate the relationship between Δ42PD1 and TNF-α or IL-6 production by INF-γ primed monocytes in response to pre-fixed E. coli. Furthermore, we assessed T-cell proliferation, activation and cytokine production as enriched CD4⁺ T cells were co-cultured with THP-1 or U937 cells, with or without Δ42PD1-blocking antibody.ResultsTreatment of human peripheral blood mononuclear cells (PBMCs) with IFN-γ resulted in an approximately 4-fold increase in the expression of Δ42PD1 on monocytes. Similarly, IFN-γ upregulates Δ42PD1 expression on human monocytic cell lines THP-1 and U937, in a time- and dose-dependent manner. IFN-γ-induced Δ42PD1 upregulation was abolished by JAK inhibitors Ruxolitinib and Tasocitinib, PI3K inhibitor LY294002, and AKT inhibitor MK-2206, respectively, but not by STAT1 inhibitor and MAPK signaling pathway inhibitors. JAK, PI3K-AKT, and MAPK signaling inhibitors abolished effectively the production of TNF-α and IL-6 in INF-γ-primed monocytes in response to pre-fixed E. coli. In contrast, Δ42PD1-specific blocking antibody did not affect the IFN-γ-induced priming effect. Furthermore, the MFI ratio of Δ42PD1 to full-length PD-1 (PD-1 Δ/F ratio) was significantly and positively correlated with TNF-α (P = 0.0289, r = 0.6038) produced by circulating CD14⁺ monocytes in response to pre-fixed E. coli. Notably, Δ42PD1 blockage significantly inhibited CD4⁺ T-cells proliferation and cytokine production in the co-culture conditions.ConclusionsWe demonstrated that IFN-γ increases Δ42PD1 expression on human monocytes via activating the PI3K/AKT signaling pathway downstream of JAKs, and that the PD-1 Δ/F ratio is a potential biomarker to predict the functional state of monocytes. Notably, we revealed the Δ42PD1 play a role in T-cell regulation, providing a novel potential approach to manipulate adaptive immune response.     

Acetylsalicylic Acid Treatment and Suppressive Regulation of AKT Accelerate Odontogenic Differentiation of Stem Cells from the Apical Papilla

Introduction

Stem cells isolated from the root apical papilla of human teeth (stem cells from the apical papilla [SCAPs]) are capable of forming tooth root dentin and are a feasible source for bioengineered tooth root regeneration. In this study, we examined the effect of acetylsalicylic acid (ASA) on odontogenic differentiation of SCAPs in vitro and in vivo.

木丹颗粒通过调控PI3K/AKT通路改善糖尿病大鼠神经病理性疼痛的研究

目的观察木丹颗粒对糖尿病大鼠神经病理性疼痛的改善作用以及对PI3K/AKT信号通路的影响。方法2018年11月—2019年4月在辽宁中医药大学实验中心进行实验。选取8周龄SPF级Wistar大鼠90只,随机选取12只作为对照组(CON),其余78只进行痛性糖尿病周围神经病变造模。取成模的60只大鼠,按随机数字表分为5组,模型组(MOD)、木丹颗粒低剂量组(MD-L)、木丹颗粒中剂量组(MD-M)、木丹颗粒高剂量组(MD-H)、甲钴胺组(JGA),每组12只,灌胃给药,每日1次,连续8周。分别于给药前和给药后2周、4周、8周检测各组大鼠血糖、体质量、机械痛阈、神经传导速度变化,8周后采用定量PCR和Western blot法检测各组大鼠PI3K和AKT mRNA和蛋白表达情况。结果与CON组比较,MOD组造模后各时间点(给药前及给药后2 w、4 w、8 w)血糖均升高(P<0.01),而体质量、机械性痛阈、神经传导速度均降低(P<0.01),PI3K和AKT mRNA及蛋白表达水平亦降低(P<0.01)。与MOD组比较,各干预组不同时间点血糖均降低(P<0.05),而体质量、机械性痛阈、神经传导速度均升高(P<0.05),PI3K和AKT mRNA及蛋白表达水平均升高,差异有统计学意义(P<0.05)。不同剂量干预组中以MD-H组改善最为显著,明显优于MD-L组和MD-M组(P<0.05),而MD-H组与JGA组比较差异无统计学意义(P>0.05)。结论木丹颗粒可能通过调控PI3K/AKT信号通路缓解糖尿病大鼠神经病理性疼痛。     

白杨素通过抑制PI3K/AKT/mTOR信号通路发挥抗炎和抗氧化作用:基于蛋白质芯片方法

目的 探讨PI3K/AKT/mTOR信号通路在白杨素抗炎抗氧化作用中的机制。方法 分别用0、5、10、15、30、60、120、240 μg/mL白杨素处理RAW264.7细胞24 h后,CCK-8法检测细胞活力。用白杨素预处理细胞2 h,加入脂多糖（100 ng/mL）分别刺激0、10、30 min,1、2、4、8、16 h,运用蛋白质芯片进行相关信号分子的筛选。用白杨素（10、30、60 μg/mL）孵育细胞2 h后,加入脂多糖刺激18 h,ELISA法检测IL-6,MCP-1和TNF-α的释放量;Griess法检测NO浓度;DCFH-DA荧光探针法检测ROS水平。设立空白对照组,白杨素（60 μg/mL）单独处理组,脂多糖（100 ng/mL）单独刺激组,以及白杨素和脂多糖联合处理组,RT-PCR法检测iNOS和COX-2的mRNA的表达量。分别用脂多糖（100 ng/mL）,N-乙酰-半胱氨酸（NAC）（20 μmol/L）或白杨素（10、30、60 μg/mL）单独或共处理细胞后,用Western blot检测炎症相关通路p-AKT、p-PRAS40、p-mTOR、mTOR、p-P70S6k、p-S6RP、 S6RP的表达水平。结果 白杨素剂量在60 μg/mL内,对细胞活力基本无影响（P>0.05）;白杨素能够降低脂多糖刺激诱导的IL-6,MCP-1,TNF-α和炎症介质NO的释放量（P<0.01）,抑制iNOS和COX-2的蛋白表达量和mRNA的表达水平（P<0.01）;蛋白质芯片筛选结果提示,脂多糖能够激活AKT/mTOR信号通路,而白杨素抑制其信号分子的活化,Western blot结果进一步验证了蛋白质芯片的结果（P<0.01）;白杨素显著下调内源性ROS的生成;运用NAC清除细胞内ROS后,炎症蛋白iNOS和COX-2的表达量下调（P<0.05）,而AKT/mTOR通路的活化被阻断（P<0.05）。结论 白杨素通过抑制上游信号分子ROS的合成,进而抑制AKT/mTOR信号通路的活化,调控核糖体的翻译过程,下调促炎细胞因子和炎症介质的合成和释放,发挥抗炎作用。     

新风胶囊通过miR-23a-3p/PTEN/PI3K/AKT/mTOR抑制骨关节炎CD4+T与软骨细胞共培养的免疫炎症

目的 观察新风胶囊（XFC）含药血清通过调控miR-23a-3p /PTEN/PI3K/AKT/mTOR信号通路抑制骨关节炎（OA）CD4+T与软骨细胞共培养中免疫炎症反应的作用机制。方法 选取30例OA患者（OA组）及30例正常人（NC组）检测miR-23a-3p、10号染色体同源丢失性磷酸酶-张力蛋白基因（PTEN）、磷脂酰肌醇-3-激酶（PI3K）、蛋白激酶B（AKT）、哺乳动物雷帕霉素靶蛋白（mTOR）的表达,观察临床指标：红细胞沉降率（ESR）、超敏C反应蛋白（hs-CRP）、IgA、IgG、IgM、补体 C3、补体C4的表达,并观察通路与临床指标的相关性。观察 30 例 OA 患者经 XFC 治疗后通路及临床指标的变化。分离及提取 OA-CD4 +T 细胞,transwell小室培养OA-CD4+T细胞与OA-CH,SD大鼠给药灌胃制备XFC含药血清;采用CCK8法检测OA-软骨细胞的细胞增殖;双荧光素酶报告实验分析miR-23a-3p和PTEN的靶向关系;RT-PCR技术检测共培养细胞中miR-23a-3p、PTENmRNA、PI3KmRNA、AKTmRNA、mTORmRNA 的表达;采用 ELISA 法检测 IL-1β、IL-6、IL-10、TNF-α的水平;Western blotting 检测PTEN、PI3K、AKT、p-AKT、mTOR、p-mTOR蛋白表达。结果 与NC组相比,OA组miR-23a-3p、PTEN、PI3K、AKT、IL-1β、IL-6、TNF-α表达显著上调,而PTEN、IL-10表达显著下调（P<0.01）;相关性分析表明：miR-23a-3p与IL-6呈正相关（P<0.01）,PI3K与IL-10呈正相关,mTOR与IL-6、IL-10、补体C3、补体C4呈正相关（P<0.01或P<0.05）;加入XFC含药血清,miR-23a-3p及PI3K/AKT/mTOR通路被抑制,L-1β、IL-6、TNF-α表达水平下降、IL-10表达水平升高（P<0.01）;Model组miR-23a-3p、PI3K、AKT、mTOR、IL-1β、IL-6和TNF-α表达水平升高,PTEN、IL-10表达水平降低（P<0.01）;miR-23a-3p经过表达后,miR-23a-3p、PI3K、AKT、mTOR、IL-1β、IL-6和TNF-α表达水平显著升高,PTEN、IL-10表达水平显著降低（P<0.01或P<0.05）;XFC组IL-1β、IL-6、TNF-α表达降低,IL-10表达升高,miR-23a-3p、PI3K、AKT、mTOR表达下调,PTEN表达上调（P<0.01或P<0.05）。结论 XFC可通过下调miR-23a-3p的表达,抑制PTEN/PI3K/AKT/mTOR通路的活化,改善IL-1β、IL-6,IL-10和TNF-α的表达,降低OA患者炎症反应。