二甲双胍对人膀胱癌细胞能量代谢的调控作用分析

目的:检测二甲双胍对人膀胱肿瘤细胞能量代谢的作用及分子机制。方法:将膀胱肿瘤细胞分为4组,分别用终浓度为0、20、40、60 mmol/L的二甲双胍处理,比色法检测各组葡萄糖的消耗和乳酸的生成,用ATP检测试剂盒检测各组ATP水平,用JC-1膜电位检测试剂盒检测二甲双胍对膀胱肿瘤细胞膜电位的影响,通过real-time PCR检测己糖激酶2(HK2)和电压依赖性阴离子通道(VDAC)的mRNA表达水平,采用Western印迹检测每组中HK2、VDAC、磷酸化信号转导与转录激活因子3(p-STAT3)的蛋白表达水平变化。结果:在20 mmol/L二甲双胍下,膀胱肿瘤细胞葡萄糖消耗增加,乳酸产生受到抑制,ATP产生和细胞线粒体膜电位降低,HK2、VDAC和p-STAT3的表达降低。结论:二甲双胍可能通过抑制HK2、VDAC和p-STAT3的表达来阻断膀胱肿瘤的糖酵解和线粒体功能,这为研究二甲双胍对肿瘤的抑制作用机制奠定了理论和实验基础。     

PKM2对乳腺癌细胞有氧糖酵解、增殖和凋亡的影响

[目的]探讨siRNA介导的PKM2基因沉默对乳腺癌细胞中有氧糖酵解、细胞增殖和凋亡产生的影响。[方法]荧光定量PCR检测乳腺癌细胞转染siRNA-PKM2的效率,葡萄糖和乳酸试剂盒及Western Blot检测细胞的糖酵解能力,CCK-8法检测细胞增殖能力,Western Blot检测细胞的凋亡状况。[结果]与对照组相比,转染PKM2的siRNA 48h后,细胞摄取葡萄糖量及乳酸分泌量均明显降低(P0.05),两种与糖酵解相关的蛋白Glut1和PFK-1表达量均降低;细胞增殖速率减慢(P0.05);抗凋亡蛋白bcl-x L蛋白表达降低,促凋亡蛋白caspase-9蛋白表达增多。[结论]siRNA介导的PKM2基因沉默能抑制乳腺癌细胞的有氧糖酵解及增殖能力,并促进细胞凋亡。     

生物能量分析仪在肿瘤细胞生物能量代谢中的应用研究

靶向肿瘤细胞代谢过程中关键调控分子抑制肿瘤细胞生长的研究日益成为热点。目前,研究肿瘤细胞氧化磷酸化和有氧糖酵解主要是应用Clark氧电极法测定细胞氧耗率以及对相关中间代谢物的测定,如乳酸和葡萄糖。但是,这些方法测定的指标相对单一,而且过程繁琐。该文详细介绍了生物能量分析仪在研究肿瘤细胞糖酵解和线粒体氧耗率中的应用,并通过研究肿瘤细胞应用阿霉素及相关药物处理后生物能量代谢的变化,深入探讨了这一方法在研究肿瘤细胞生物能量代谢方面中的优越性。研究结果表明,羰基氰–对–三氟甲氧基本腙(carbonylcyanide p-trifluoro methoxyphenylhydrazone,FCCP)的浓度以及细胞数量对于研究肿瘤细胞的氧耗率十分关键,应用阿霉素能够显著抑制肿瘤细胞的有氧糖酵解和线粒体氧耗率。通过该文的介绍,期望能为肿瘤细胞生物能量代谢研究提供进一步的参考。     

微RNA在肿瘤细胞糖代谢中的功能

大多数癌细胞产生能量是通过高速率糖酵解,然后在胞液中进行乳酸发酵。而在大多数正常细胞中,糖酵解速率相对较低,丙酮酸主要在线粒体中进行有氧氧化。即使在氧充足的条件下,快速生长的恶性肿瘤细胞进行糖酵解的速率通常要比其正常组织来源的细胞高二百多倍。微RNA（microRNA,miRNA）是一类具有转录后调控功能的非编码RNA。近年来,越来越多的研究表明,miRNA主要通过诱导缺氧环境、影响葡萄糖摄入、调节糖酵解过程中的关键酶以及乳酸去路等诸多方面参与糖代谢过程,从而在肿瘤细胞糖代谢中发挥重要作用。     

LncRNA D5在卵巢癌组织中的表达及其功能研究

目的:探讨LncRNA D5在卵巢癌组织中的表达及其对卵巢癌细胞糖代谢的影响和与卵巢癌患者预后的关系。方法:采用实时定量聚合酶链反应法(q RT-PCR)测定62例卵巢癌患者组织LncRNA D5表达,Kaplan-Meier生存分析其表达与患者预后的关系,设计合成LncRNA D5/p EX-2真核过表达质粒,分别在卵巢癌细胞SKOV3、A2780中进行转染,实验分为空白对照组及转染组,48 h后测定卵巢癌细胞SKOV3、A2780的葡萄糖摄取能力、糖酵解速率、氧耗以及乳酸排除率。结果:LncRNA D5在良性卵巢肿瘤或正常卵巢组织中表达比较均一,其在卵巢癌中的表达与良性卵巢肿瘤或正常卵巢组织相比,具有显著差异(P0.05)。LncRNA D5表达下调的卵巢癌患者总生存期和无瘤生存期均较LncRNA D5表达上调的卵巢癌患者明显缩短(P0.05)。通过转染上调A2780、SKOV3中的LncRNA D5,细胞的葡萄糖摄取能力、糖酵解速率以及乳酸排出显著上调,而细胞的氧消耗明显下降(P0.05)。结论:LncRNA D5在卵巢癌中表达异常,与卵巢癌患者的预后不良相关,LncRNA D5对卵巢癌细胞的糖酵解能力具有一定的调控作用。     

巨噬细胞集落刺激因子经PI3K/AKT信号途径影响人乳腺癌MCF-7细胞糖代谢

本文探讨巨噬细胞集落刺激因子（M-CSF）对人乳腺癌MCF-7细胞糖代谢的影响及其机制. 构建胞质稳定转染 M-CSF的MCF-7细胞（MCF-7-M）;ATP检测试剂盒检测MCF-7和MCF-7-M细胞的ATP生成;葡萄糖测定试剂盒、乳酸测试盒检测MCF-7和MCF-7-M细胞的葡萄糖摄取和乳酸分泌情况;蛋白质印迹法检测在糖酵解抑制剂2-脱氧葡萄糖（2-DG）和氧化磷酸化抑制剂OLIG处理后,M-CSF对MCF-7细胞的糖酵解关键酶：己糖激酶2（HK2）、丙酮酸激酶M2（PKM2）及葡萄糖转运体1（GLUT-1）表达的影响;MTT法检测在ATP消耗剂3-溴丙酮酸（3-BrPA）处理后,MCF-7和MCF-7-M细胞对5-FU敏感性的变化. 结果发现：MCF-7-M细胞的ATP水平显著高于MCF-7细胞（P<0.05）;2-DG降低了MCF-7和MCF-7-M细胞的ATP水平,并且降低MCF-7-M细胞ATP的效果更明显（P<0.01）;MCF-7-M细胞的糖摄取能力和乳酸分泌量显著高于MCF-7细胞（P<0.01）,经API-2处理后,MCF-7和MCF-7-M细胞葡萄糖消耗和乳酸分泌量均显著减少（P<0.01）;MCF-7-M细胞GLUT-1、HK2和PKM2的表达显著高于MCF-7细胞（P<0.01）;LY294002和API-2均可抑制MCF-7-M细胞GLUT-1的表达（P<0.05）;用3-BrPA处理后,MCF-7-M和MCF-7细胞对5-FU的药物敏感性显著增强（P<0.01). 综上,得出结论： 胞质M-CSF通过诱导GLUT-1、HK2和PKM2的表达,活化MCF-7细胞糖酵解途径;PI3K/AKT信号通路参与胞质M-CSF活化MCF-7细胞的糖酵解途径.     

肾脏细胞CD36在炎症因子诱导的脂肪酸摄取及脂质沉积中的作用

慢性炎症和脂质代谢紊乱是慢性肾病的重要特征,炎症因子影响肾脏细胞脂质代谢的作用机制尚不清楚,该研究旨在探讨炎症因子是否通过上调脂肪酸转运酶CD36的表达促进肾脏细胞脂肪酸摄取及脂质沉积。通过给予HMCs及HK2细胞肿瘤坏死因子(tumor necrosis factor-α,TNF-α)和白介素6(interleukin-6, IL-6)刺激处理24 h,应用qRT-PCR检测CD36的表达量,酶法检测HK2细胞内的甘油三酯(triglycercide, TG)水平。构建CD36过表达的细胞模型,使用荧光标记脂肪酸,观测细胞对外源性脂肪酸的摄取速率。然后利用小RNA干扰技术,构建CD36低表达的细胞模型,检测CD36低表达时细胞脂肪酸摄取速率及胞内甘油三酯、游离脂肪酸(free fatty acid, FFA)含量,葡萄糖调节蛋白78(GRP78)及内质网跨膜激酶(IRE1)的m RNA表达量。结果显示,炎性因子TNF-α和IL-6促进HMCs及HK2细胞TG的累积增加,并刺激细胞CD36的表达; CD36过表达促进HMCs及HK2细胞对FFA的摄取。当CD36表达被干扰后,炎性因子诱导的肾脏细胞TG及FFA的累积增加、FFA的摄取速率、细胞内GRP78、IRE-1的m RNA表达量及ROS含量均受到了抑制。该项研究表明,在HMCs及HK2细胞中,炎症因子可能通过促进CD36表达,导致细胞对FFA摄取增多,进而引起细胞脂质积聚;干预CD36能够改善炎性因子引起的脂质积聚、内质网应激以及细胞损伤,提示CD36可作为慢性肾脏疾病的潜在治疗靶点。     

CDK4基因沉默对非小细胞肺癌A549 增殖和代谢的影响

目的:通过特异性小干扰RNA(small interfering RNA,si RNA),使CDK4基因沉默,探讨该基因沉默对肺癌A549细胞增殖和代谢的影响及其可能的作用机制。方法:将靶向CDK4小干扰RNA(si RNA-CDK4)和阴性对照干扰片段(si RNA-control)成功转染A549细胞后,利用实时荧光定量PCR和蛋白质免疫印迹法分别检测CDK4在m RNA和蛋白水平的变化;细胞计数法、CCK-8法和软琼脂糖克隆形成实验检测A549增殖的变化和克隆形成能力;FCM法检测A549细胞的细胞周期;18F-FDG摄取实验、乳酸检测试剂盒及海马技术检测A549细胞中葡萄糖、乳酸的量及氧耗的变化;利用RT-PCR检测CDK4基因沉默后A549细胞中糖代谢相关酶m RNA水平的变化。结果:将靶向CDK4小干扰RNA(si RNA-CDK4)转染A549细胞后,可明显抑制CDK4的m RNA和蛋白表达(P0.001,P0.01)。CDK4蛋白抑制后,细胞增殖在48、72和96 h均明显降低(P值均0.05),G1期细胞比例明显增多,S期细胞比例明显减少(P值均0.05);18F-FDG摄取量下降(42.21±1.90)%(P0.05),乳酸的生成量减少(29.39±5.35)%(P0.05),而细胞的基础耗氧量增加(67.17±3.58)%(P0.01);糖酵解相关酶PFKFB3、PKM2、LDHA在m RNA水平均明显减低(P0.001,P0.01,P0.001)。结论:抑制CDK4表达可明显降低糖酵解水平,并增加耗氧量;同时可引起细胞周期阻滞,抑制肿瘤细胞增殖。其机制可能与CDK4直接或间接调节糖酵解相关酶的表达有关。     

18β-甘草次酸通过PGK1糖酵解途径抑制oxLDL诱导的血管内皮细胞凋亡研究

基于磷酸甘油酸激酶1(phosphoglycerate kinase 1,PGK1)介导糖酵解途径研究18β-甘草次酸(18β-glycyrrhetinic acid, GA)抑制氧化低密度脂蛋白(oxidized low density lipoprotein, oxLDL)诱导的血管内皮细胞凋亡的分子机制。采用oxLDL(100 mg/L)损伤建立体外人主动脉内皮细胞损伤模型,并给予不同浓度的GA(10、20和40μmol/L)及PGK1激动剂进行干预,Western blot法检测糖酵解关键酶PGK1、葡萄糖转运蛋白1(glucose transporter 1,GLUT1)、己糖激酶(hexokinase 2,HK2)和丙酮酸激酶M2(pyruvate kinase M2,PKM2)表达水平以及凋亡相关Bax、Bcl2、Caspase-3和Caspase-9蛋白表达水平,比色法检测细胞内乳酸和葡萄糖含量。结果表明,与对照组相比,oxLDL组内皮细胞葡萄糖消耗减少、乳酸分泌量增加,PGK1、GLUT1、HK2、PKM2、Bax、cleaved Caspase-3及cleaved ...     

乳酸脱氢酶和Warburg效应的研究进展

糖代谢过程的关键限速酶乳酸脱氢酶(lactate dehydrogenase,LDH)可提升糖酵解速率和促使局部形成酸性微环境。研究发现LDH与恶性肿瘤关系密切,LDH通过Warburg效应调节乳酸产生,而适当的酸性调控则对LDH形成负反馈调节回路。肿瘤细胞的LDH-A基因异常激活常伴随着LDH-B基因的异常失活,LDH-A的异常激活及丙酮酸脱氢酶的失活,可进一步促使丙酮酸转化为乳酸,后者不仅仅作为代谢产物,而且是肿瘤细胞的主要能量来源。     

Lactate-Modulated Induction of THBS-1 Activates Transforming Growth Factor (TGF)-beta2 and Migration of Glioma Cells In Vitro

Background

An important phenomenon observed in glioma metabolism is increased aerobic glycolysis in tumor cells, which is generally referred to as the Warburg effect. Transforming growth factor (TGF)-beta2, which we previously showed to be induced by lactic acid, is a key pathophysiological factor in glioblastoma, leading to increased invasion and severe local immunosuppression after proteolytic cleavage from its latency associated peptide. In this study we tested the hypothesis, that lactate regulates TGF-beta2 expression and glioma cell migration via induction of Thrombospondin-1 (THBS-1), a TGF-beta activating protein.

Methods

Lactate levels were reduced by knockdown of LDH-A using specific small interfering RNA (siRNA) and competitive inhibition of LDH-A by sodium oxamate. Knockdown of THBS-1 was performed using specific siRNA. Western Blot, qRT-PCR, and ELISA were used to investigate expression levels of LDH-A, LDH-B, TGF-beta2 and THBS-1. Migration of cells was examined by Spheroid, Scratch and Boyden Chamber assays.

Results

Knockdown of LDH-A with subsequent decrease of lactate concentration leads to reduced levels of THBS-1 and TGF-beta2 in glioma cells. Lactate addition increases THBS-1 protein, leading to increased activation of TGF-beta2. Inhibition of THBS-1 reduces TGF-beta2 protein and migration of glioma cells. Addition of synthetic THBS-1 can rescue reduced TGF-beta2 protein levels and glioma cell migration in siLDH-A treated cells.

Conclusion

We define a regulatory cascade between lactate, THBS-1 and TGF-beta2, leading to enhanced migration of glioma cells. Our results demonstrate a specific interaction between tumor metabolism and migration and provide a better understanding of the mechanisms underlying glioma cell invasion.     

ANXA2P2/miR-9/LDHA axis regulates Warburg effect and affects glioblastoma proliferation and apoptosis

BackgroundAerobic glycolysis is a unique tumor cell phenotype considered as one of the hallmarks of cancer. Aerobic glycolysis can accelerate tumor development by increasing glucose uptake and lactate production. In the present study, lactate dehydrogenase A (LDHA) is significantly increased within glioma tissue samples and cells, further confirming the oncogenic role of LDHA within glioma.MethodsHematoxylin and eosin (H&E) and immunohistochemical (IHC) staining were applied for histopathological examination. The protein levels of LDHA, transporter isoform 1 (GLUT1), hexokinase 2 (HK2), phosphofructokinase (PFK) in target cells were detected by Immunoblotting. The predicted miR-9 binding to lncRNA Annexin A2 Pseudogene 2 (ANXA2P2) or the 3′ untranslated region (UTR) of LDHA was verified using Luciferase reporter assay. Cell viability or apoptosis were examined by MTT assay or Flow cytometry. Intracellular glucose and Lactate levels were measured using glucose assay kit and lactate colorimetric assay kit.ResultsThe expression of ANXA2P2 showed to be dramatically upregulated within glioma tissue samples and cells. Knocking down ANXA2P2 within glioma cells significantly inhibited cell proliferation and aerobic glycolysis, as manifested as decreased lactate and increased glucose in culture medium, and downregulated protein levels of glycolysis markers, GLUT1, HK2, PFK, as well as LDHA. miR-9 was predicted to target both lncRNA ANXA2P2 and LDHA. The overexpression of miR-9 suppressed the cell proliferation and aerobic glycolysis of glioma cells. Notably, miR-9 could directly bind to LDHA 3′UTR to inhibit LDHA expression and decrease the protein levels of LDHA. ANXA2P2 competitively targeted miR-9, therefore counteracting miR-9-mediated repression on LDHA. Within tissues, miR-9 exhibited a negative correlation with ANXA2P2 and LDHA, respectively, whereas ANXA2P2 and LDHA exhibited a positive correlation with each other.ConclusionsIn conclusion, ANXA2P2/miR-9/LDHA axis modulates the aerobic glycolysis progression in glioma cells, therefore affecting glioma cell proliferation.     

Silencing of CD147 inhibits hepatic stellate cells activation related to suppressing aerobic glycolysis via hedgehog signaling

Hepatic stellate cells (HSCs) activation is a key step that promotes hepatic fibrosis. Emerging evidence suggests that aerobic glycolysis is one of its important metabolic characteristics. Our previous study has reported that CD147, a glycosylated transmembrane protein, contributes significantly to the activation of HSCs. However, whether and how it is involved in the aerobic glycolysis of HSCs activation is unknown. The objective of the present study was to validate the effect of CD147 in HSCs activation and the underlying molecular mechanism. Our results showed that the silencing of CD147 decreased the expression of α-smooth muscle-actin (α-SMA) and collagen I at both mRNA and protein levels. Furthermore, CD147 silencing decreased the glucose uptake, lactate production in HSCs, and repressed the lactate dehydrogenase (LDH) activity, the expression of hexokinase 2 (HK2), glucose transporter 1 (Glut1). The effect of galloflavin, a well-defined glycolysis inhibitor, was similar to CD147 siRNA. Mechanistically, CD147 silencing suppressed glycolysis-associated HSCs activation through inhibiting the hedgehog signaling. Moreover, the hedgehog signaling agonist SAG could rescue the above effect of CD147 silencing. In conclusion, CD147 silencing blockade of aerobic glycolysis via suppression of hedgehog signaling inhibited HSCs activation, suggesting CD147 as a novel therapeutic target for hepatic fibrosis.Supplementary InformationThe online version contains supplementary material available at 10.1007/s10616-021-00460-9.     

MFN1在肝癌转移中的调控作用研究

目的:探讨线粒体融合蛋白MFN1(mito-fusion 1)在肝癌转移中的作用及其机制。方法:1).采用免疫组化实验检测15对肝癌转移灶组织与原发灶组织中MFN1的表达,以明确肝癌转移时是否伴有MFN1表达的改变。2).采用si RNA (small interference RNA)下调肝癌细胞中MFN1的表达后,提高Transwell迁移实验和Transwell侵袭实验分别检测其迁移和侵袭能力,通过实时荧光定量PCR (Quantitative Real-time PCR,qRT-PCR)和Western blot实验分别检测基质金属蛋白酶1 (matrix metalloproteinase 1,MMP1)、MMP2、MMP7及MMP9的m RNA和蛋白表达。结果:1)肝癌转移灶组织中MFN1表达显著低于原发灶组织(P0.05)。2).下调MFN1表达后,肝癌细胞的迁移和侵袭能力显著升高,MMP7的表达显著增加,而MMP1、MMP2与MMP9的表达无明显变化。结论:线粒体融合蛋白MFN1在肝癌转移组织中表达显著降低,可能通过激活MMP7表达,促进肝癌细胞侵袭和转移。     

Long noncoding RNA DLEU1 promotes proliferation and glycolysis of gastric cancer cells via APOC1 upregulation by recruiting SMYD2 to induce trimethylation of H3K4 modification

ObjectivesAPOC1 has been reported to promote tumor progression. Nevertheless, its impact on cell proliferation and glycolysis in gastric cancer (GC) remains to be probed. Hence, this study explored the related impacts and mechanisms.MethodsDLEU1, SMYD2, and APOC1 expression was detected in GC cells. Afterward, ectopic expression and knockdown experiments were conducted in GC cells, followed by measurement of cell proliferation, glucose uptake capability, lactic acid production, ATP content, extracellular acidification rate (ECAR), oxygen consumption rate (OCR), and GLUT1, HK2, and LDHA expression. In addition, interactions between DLEU1 and SMYD2 were analyzed with RIP and RNA pull down assays, and the binding of SMYD2 to APOC1 promoter and the methylation modification of SMYD2 in H3K4me3 were assessed with a ChIP assay. The ectopic tumor formation experiment in nude mice was conducted for in vivo validation.ResultsDLEU1, SMYD2, and APOC1 were highly expressed in GC cells. The downregulation of DLEU1 or APOC1 inhibited glucose uptake capability, lactic acid production, ECAR, the expression of GLUT1, HK2, and LDHA, ATP contents, and proliferation but augmented OCR in GC cells, which was also verified in animal experiments. Mechanistically, DLEU1 interacted with SMYD2 and recruited SMYD2 to APOC1 promoter to promote H3K4me3 modification, thus facilitating APOC1 expression. Furthermore, the effects of DLEU1 silencing on GC cell proliferation and glycolysis were negated by overexpressing SMYD2 or APOC1.ConclusionLncRNA DLEU1 recruited SMYD2 to upregulate APOC1 expression, thus boosting GC cell proliferation and glycolysis.     

Tyrosine phosphorylation of lactate dehydrogenase A is important for NADH/NAD(+) redox homeostasis in cancer cells

The Warburg effect describes an increase in aerobic glycolysis and enhanced lactate production in cancer cells. Lactate dehydrogenase A (LDH-A) regulates the last step of glycolysis that generates lactate and permits the regeneration of NAD(+). LDH-A gene expression is believed to be upregulated by both HIF and Myc in cancer cells to achieve increased lactate production. However, how oncogenic signals activate LDH-A to regulate cancer cell metabolism remains unclear. We found that the oncogenic receptor tyrosine kinase FGFR1 directly phosphorylates LDH-A. Phosphorylation at Y10 and Y83 enhances LDH-A activity by enhancing the formation of active, tetrameric LDH-A and the binding of LDH-A substrate NADH, respectively. Moreover, Y10 phosphorylation of LDH-A is common in diverse human cancer cells, which correlates with activation of multiple oncogenic tyrosine kinases. Interestingly, cancer cells with stable knockdown of endogenous LDH-A and rescue expression of a catalytic hypomorph LDH-A mutant, Y10F, demonstrate increased respiration through mitochondrial complex I to sustain glycolysis by providing NAD(+). However, such a compensatory increase in mitochondrial respiration in Y10F cells is insufficient to fully sustain glycolysis. Y10 rescue cells show decreased cell proliferation and ATP levels under hypoxia and reduced tumor growth in xenograft nude mice. Our findings suggest that tyrosine phosphorylation enhances LDH-A enzyme activity to promote the Warburg effect and tumor growth by regulating the NADH/NAD(+) redox homeostasis, representing an acute molecular mechanism underlying the enhanced lactate production in cancer cells.