摘要
研究显示,丙酮酸代谢的改变在结直肠癌的发生发展中起重要作用,而结直肠癌干细胞中microRNA(miRNA)表达异常可能与丙酮酸代谢密切相关。笔者前期通过TCGA数据库分析发现,miR-520c-3p在结直肠癌中表达升高,且与预后相关。然而,miR-520c-3p是否参与了丙酮酸代谢尚不清楚。因此,本研究探讨结直肠癌干细胞中miR-520c-3p的表达与丙酮酸代谢的关系。
选择人结肠癌细胞株,并从中分离纯化结直肠癌干细胞。检测过表达或敲低miR-520c-3p后,结直肠癌干细胞及结直肠癌细胞增殖能力、丙酮酸氧化水平、乳酸产量的变化。用D-[U
过表达miR-520c-3p后,结直肠癌干细胞的增殖能力明显增强、丙酮酸氧化水平明显下降、乳酸产量明显升高(均P<0.05);用D-(U
丙酮酸的代谢途径取决于细胞当时的条件以及有机体种类或组织的类
HCT-116细胞株购自宝如亿(北京)生物技术有限公司(货号:RX1525)。HT-29细胞株购自深圳市文乐生物科技有限公司(货号:iCell-h078)。SW-1116细胞株购自上海信裕生物科技有限公司(货号:26-5140)。DMEM培养基购自北京赛音图科技有限公司(货号:C11995500BT)。MPC1抗体购自广州吉英生物科技有限公司(货号:42898)。GAPDH抗体购自艾比玛特医药科技(上海)有限公司(货号:BCJ200003H)。miR-520c-3p模拟物(mimics)和miR-520c-3p抑制物(inhibitor)由北京擎科设计合成。含MPC1抑制物(shMPC1)和阴性对照序列(shNC)的慢病毒由汉坦生物提供。L-乳酸检测试剂盒购自北京轩泽伟业科技有限公司(货号:K-LATE)。葡萄糖检测试剂盒购自北京奇松生物科技有限公司(货号:BQS118529-100T)。CyQuant细胞增殖测定试剂盒购自ThermoFisher公司(货号:C7026)。RNeasy Mini Kit购自北京强欣博瑞生物技术有限公司(货号:74134)。高容量cDNA反转录试剂盒购自ThermoFisher公司(货号:4374967)。SYBR Green I Master Mix购自北京擎科生物科技有限公司(货号:TSE203)。
根据文
根据TCGA数据库(http://cancergenome.nih.gov)数据集COAD和COADREAD,利用Survexpress比较目标基因高表达和低表达的结直肠癌患者的生存状况。
乳酸含量通过使用L-乳酸检测试剂盒进行测定。葡萄糖通过葡萄糖检测试剂盒进行检测。将结直肠癌干细胞HCT-116CSC、HT-29CSC、SW-1116CSC在DMEM基本培养基中培养,然后根据制造商的说明收集细胞并进行乳酸或葡萄糖含量测定。
结直肠癌干细胞使用裂解缓冲液50 mmol/L HEPES,150 mmol/L NaCl,10% Glycerol,1% Triton X-100,1.5 mmol/L MgCl,1.0 mmol/L EGTA,10 mmol/L焦磷酸钠,100 mmol/L氟化钠,1 mmol/L苯甲基磺酰氟(PMSF)裂解。样品的蛋白质浓度通过BCA检测进行量化,并进行归一化处理,以确保各孔之间的样品负荷恒定。然后对样品进行SDS-聚丙烯酰胺凝胶电泳(PAGE)和免疫印迹。用18%丙烯酰胺凝胶进行解析,并转移到甲醇激活的0.45 μm Immobilon FL PVDF膜上。在2.5%的牛奶中阻断1 h后,清洗膜并使用在含有0.1% Tween-20的TBS中制成的5% BSA溶液中稀释的特异性抗体进行检测。洗涤膜并使用荧光共轭二抗进行探测,并使用LI-COR Biosciences Odyssey系统进行扫描。
所有
代谢测量是在标准的24孔Seahorse微孔板上在Seahorse XF24分析仪上进行的。糖酵解是根据糖酵解应激测试套件测量的,并显示为细胞外酸化率(extracellular acidification rate,ECAR)。当细胞在含有10 mmol/L丙酮酸钠作为唯一呼吸底物培养时,使用氧消耗率(oxygen consumption rate,OCR)测量丙酮酸的氧化。对于所有的实验,在分析前16~18 h,每孔有8万个细胞。
根据制造商的说明,使用RNeasy Mini Kit从细胞中提取和纯化总RNA。对于miRNA测序,纯化的总RNA交由华大基因测序。对于实时荧光定量PCR,使用高容量cDNA反转录试剂盒合成cDNA。随后,用LightCycler 480 SYBR Green I Master Mix进行实时PCR。所有反应至少进行了4次。
过表达或敲低miR-520c-3p后,结直肠癌细胞(HCT-116、HT-29、SW-1116)的增殖水平均无明显变化(均P>0.05)。过表达miR-520c-3p后,结直肠癌干细胞(HCT-116CSC、HT-29CSC、SW-1116CSC)的增殖水平均明显增强(均P<0.05);敲低miR-520c-3p后,结直肠癌干细胞HCT-116CSC、HT-29CSC、SW-1116CSC的增殖水平明显降低(均P<0.05)(

图1 细胞增殖能力检测 A-C:过表达或敲低miR-520c-3p后,结直肠癌细胞的增殖水平;D-F:过表达或敲低miR-520c-3p后,结直肠癌干细胞的增殖水平
Figure 1 Cell proliferation assay A-C: Proliferation levels of colorectal cancer cells after overexpression or knockdown of miR-520c-3p; D-F: Proliferation levels of colorectal cancer stem cells after overexpression or knockdown of miR-520c-3p
过表达或敲低miR-520c-3p后,结直肠癌细胞的丙酮酸氧化水平均无明显变化(均P>0.05)。过表达miR-520c-3p后,结直肠癌干细胞的丙酮酸氧化水平均明显下降(均P<0.05);敲低miR-520c-3p后,结直肠癌干细胞的丙酮酸氧化水平均明显上升(均P<0.05)(

图2 丙酮酸代谢检测 A:过表达或敲低miR-520c-3p后,结直肠癌细胞以及结直肠癌干细胞的丙酮酸氧化水平;B-D:过表达或敲低miR-520c-3p的结直肠癌干细胞中,D-(U
Figure 2 Acetate pyruvate assay A: Pyruvate oxidation levels in colorectal cancer cells and colorectal cancer stem cells after overexpression or knockdown of miR-520c-3p; B-D: Mass isotopomer analysis of citrate (m+0, m+1, m+2, m+3, m+4, m+5, m+6) in colorectal cancer stem cells with overexpression or knockdown of miR-520c-3p after D-(U
过表达或敲低miR-520c-3p后,结直肠癌干细胞SW-1116CSC中多种基因的转录水平受到调控,经过生物信息学软件预测发现miR-520c-3p可以与线粒体丙酮酸载体1(mitochondrial pyruvate carrier 1,MPC1)mRNA 3'UTR相结合(

图3 miR-520c-3p靶向MPC1调控结直肠癌干细胞丙酮酸代谢 A:过表达或敲低miR-520c-3p后,结直肠癌干细胞SW-1116CSC的转录组热图;B:生物信息学软件预测miR-520c-3p与MPC1 mRNA 3'UTR的结合位点;C:荧光素酶报告实验检测miR-520c-3p与MPC1 mRNA 3'UTR的结合;D-E:过表达或敲低miR-520c-3p后,结直肠癌细胞中MPC1的mRNA和蛋白质表达水平;F:MPC1不同表达水平对结直肠癌生存曲线的影响;G:图中所示处理下,结直肠癌细胞以及结直肠癌干细胞的丙酮酸氧化水平;H-J:各种处理下,D-(U
Figure 3 MiR-520c-3p regulating pyruvate metabolism of colorectal cancer stem cells by targeting MPC1 A: Heatmap of transcriptome analysis in SW-1116CSC colorectal cancer stem cells with overexpression or knockdown of miR-520c-3p; B: Prediction of binding sites between miR-520c-3p and MPC1 mRNA 3'UTR using bioinformatics software; C: Luciferase reporter assay to detect the binding of miR-520c-3p to MPC1 mRNA 3'UTR; D-E: The mRNA and protein expression levels of MPC1 in colorectal cancer cells after overexpression or knockdown of miR-520c-3p; F: Impact of different expression levels of MPC1 on survival curve of colorectal cancer; G: Pyruvate oxidation levels in colorectal cancer cells and colorectal cancer stem cells under various treatments; H-J: Mass isotopomer analysis of citrate (m+0, m+1, m+2, m+3, m+4, m+5, m+6) after D-(U
在全世界的癌症发病率和病死率排名中,结直肠癌分别位列第三和第
大多数分化的细胞通过糖酵解在细胞液中把葡萄糖转化为丙酮酸,然后在线粒体中进行丙酮酸氧
本研究发现miR-520c-3p可以靶向MPC1 mRNA 3'UTR。过表达miR-520c-3p后,结直肠癌干细胞中MPC1的mRNA水平和蛋白水平显著下降。同时,本研究的数据显示,敲低MPC1的结直肠癌干细胞中线粒体代谢发生了改变,增加了细胞内丙酮酸和乳酸的数量。MPC1是一种将丙酮酸转移到线粒体的内膜蛋白,抑制MPC1的表达会使癌细胞转向上皮细胞-间充质转化和谷氨酸溶
综上所述,结直肠癌中高表达的miR-520c-3p与较差的预后相关,其作用机制可能与miR-520c-3p靶向MPC1调控结直肠癌干细胞中的丙酮酸代谢水平,促进了结直肠癌干细胞的增殖有关。
作者贡献声明
赵英旋负责科研设计、数据分析;白玉勤负责病例收集、文章写作修改;欧阳卫东负责指导以及文章修改。
利益冲突
所有作者均声明不存在利益冲突。
参考文献
Zhu SS, Guo YY, Zhang X, et al. Pyruvate kinase M2 (PKM2) in cancer and cancer therapeutics[J]. Cancer Lett, 2021, 503:240-248. doi: 10.1016/j.canlet.2020.11.018. [百度学术]
Kiesel VA, Sheeley MP, Coleman MF, et al. Pyruvate carboxylase and cancer progression[J]. Cancer Metab, 2021, 9(1): 20. doi: 10.1186/s40170-021-00256-7. [百度学术]
He D, Feng HJ, Sundberg B, et al. Methionine oxidation activates pyruvate kinase M2 to promote pancreatic cancer metastasis[J]. Mol Cell, 2022, 82(16):3045-3060. doi: 10.1016/j.molcel.2022.06.005. [百度学术]
Ruiz-Iglesias A, Mañes S. The importance of mitochondrial pyruvate carrier in cancer cell metabolism and tumorigenesis[J]. Cancers, 2021, 13(7):1488. doi: 10.3390/cancers13071488. [百度学术]
El-Far AH, Al Jaouni SK, Li XT, et al. Cancer metabolism control by natural products: Pyruvate kinase M2 targeting therapeutics[J]. Phytother Res, 2022, 36(8):3181-3201. doi: 10.1002/ptr.7534. [百度学术]
Wen YC, Chen WY, Tram VTN, et al. Pyruvate kinase L/R links metabolism dysfunction to neuroendocrine differentiation of prostate cancer by ZBTB10 deficiency[J]. Cell Death Dis, 2022, 13(3):252. doi: 10.1038/s41419-022-04694-z. [百度学术]
McFate T, Mohyeldin A, Lu HS, et al. Pyruvate dehydrogenase complex activity controls metabolic and malignant phenotype in cancer cells[J]. J Biol Chem, 2008, 283(33):22700-22708. doi: 10.1074/jbc.M801765200. [百度学术]
Apostolidi M, Vathiotis IA, Muthusamy V, et al. Targeting pyruvate kinase M2 phosphorylation reverses aggressive cancer phenotypes[J]. Cancer Res, 2021, 81(16):4346-4359. doi: 10.1158/0008-5472.CAN-20-4190. [百度学术]
Jadhav J, Das R, Kamble S, et al. Ferrocene-based modulators of cancer-associated tumor pyruvate kinase M2[J]. J Organomet Chem, 2022, 968:122338. doi: 10.1016/j.jorganchem.2022.122338. [百度学术]
Rihan M, Vineela Nalla L, Dharavath A, et al. Boronic acid derivative activates pyruvate kinase M2 indispensable for redox metabolism in oral cancer cells[J]. Bioorg Med Chem Lett, 2022, 59:128539. doi: 10.1016/j.bmcl.2022.128539. [百度学术]
Hong J, Xie ZY, Yang FY, et al. Erianin suppresses proliferation and migration of cancer cells in a pyruvate carboxylase-dependent manner[J]. Fitoterapia, 2022, 157:105136. doi: 10.1016/j.fitote.2022.105136. [百度学术]
Adnan M, Shamsi A, Elasbali AM, et al. Structure-guided approach to discover tuberosin as a potent activator of pyruvate kinase M2, targeting cancer therapy[J]. Int J Mol Sci, 2022, 23(21):13172. doi: 10.3390/ijms232113172. [百度学术]
Hill M, Tran N. miRNA interplay: mechanisms and consequences in cancer[J]. Dis Model Mech, 2021, 14(4):dmm047662. doi: 10.1242/dmm.047662. [百度学术]
Yang ZP, Lu S, Wang YY, et al. A novel defined necroptosis-related miRNAs signature for predicting the prognosis of colon cancer[J]. Int J Gen Med, 2022, 15:555-565. doi: 10.2147/IJGM.S349624. [百度学术]
Deng YH, Deng ZH, Hao H, et al. microRNA-23a promotes colorectal cancer cell survival by targeting PDK4[J]. Exp Cell Res, 2018, 373(1/2):171-179. doi: 10.1016/j.yexcr.2018.10.010. [百度学术]
Cheng CC, Liao PN, Ho AS, et al. STAT3 exacerbates survival of cancer stem-like tumorspheres in EGFR-positive colorectal cancers: RNAseq analysis and therapeutic screening[J]. J Biomed Sci, 2018, 25(1):60. doi: 10.1186/s12929-018-0456-y. [百度学术]
Chattopadhyay I, Dhar R, Pethusamy K, et al. Exploring the role of gut microbiome in colon cancer[J]. Appl Biochem Biotechnol, 2021, 193(6):1780-1799. doi: 10.1007/s12010-021-03498-9. [百度学术]
Martínez-Gutierrez A, Carbajal-Lopez B, Bui TM, et al. A microRNA panel that regulates proinflammatory cytokines as diagnostic and prognosis biomarkers in colon cancer[J]. Biochem Biophys Rep, 2022, 30:101252. doi: 10.1016/j.bbrep.2022.101252. [百度学术]
Ding RL, Hong WW, Huang L, et al. Examination of the effects of microRNA-145-5p and phosphoserine aminotransferase 1 in colon cancer[J]. Bioengineered, 2022, 13(5):12794-12806. doi: 10.1080/21655979.2022.2071010. [百度学术]
Díez-Villanueva A, Sanz-Pamplona R, Solé X, et al. COLONOMICS - integrative omics data of one hundred paired normal-tumoral samples from colon cancer patients[J]. Sci Data, 2022, 9(1):595. doi: 10.1038/s41597-022-01697-5. [百度学术]
Goc J, Lv MZ, Bessman NJ, et al. Dysregulation of ILC3s unleashes progression and immunotherapy resistance in colon cancer[J]. Cell, 2021, 184(19):5015-5030. doi: 10.1016/j.cell.2021.07.029. [百度学术]
Naik H, Johnson MDD, Johnson MR. Internet interest in colon cancer following the death of Chadwick boseman: infoveillance study[J]. J Med Internet Res, 2021, 23(6):e27052. doi: 10.2196/27052. [百度学术]
Qian XW, Jiang C, Zhu ZT, et al. Long non-coding RNA LINC00511 facilitates colon cancer development through regulating microRNA-625-5p to target WEE1[J]. Cell Death Discov, 2022, 8(1):233. doi: 10.1038/s41420-021-00790-9. [百度学术]
Fan WH, Wang FC, Jin Z, et al. Curcumin synergizes with cisplatin to inhibit colon cancer through targeting the microRNA-137-glutaminase axis[J]. Curr Med Sci, 2022, 42(1):108-117. doi: 10.1007/s11596-021-2469-0. [百度学术]
Lee YB, Min JK, Kim JG, et al. Multiple functions of pyruvate kinase M2 in various cell types[J]. J Cell Physiol, 2022, 237(1):128-148. doi: 10.1002/jcp.30536. [百度学术]
Sebastian C, Ferrer C, Serra M, et al. A non-dividing cell population with high pyruvate dehydrogenase kinase activity regulates metabolic heterogeneity and tumorigenesis in the intestine[J]. Nat Commun, 2022, 13(1):1503. doi: 10.1038/s41467-022-29085-y. [百度学术]
Xue C, Li GL, Bao ZY, et al. Mitochondrial pyruvate carrier 1: a novel prognostic biomarker that predicts favourable patient survival in cancer[J]. Cancer Cell Int, 2021, 21(1):288. doi: 10.1186/s12935-021-01996-8. [百度学术]
Jiang HF, Alahmad A, Fu S, et al. Identification and characterization of novel MPC1 gene variants causing mitochondrial pyruvate carrier deficiency[J]. J Inherit Metab Dis, 2022, 45(2):264-277. doi: 10.1002/jimd.12462. [百度学术]
Xu L, Phelix CF, Chen LY. Structural insights into the human mitochondrial pyruvate carrier complexes[J]. J Chem Inf Model, 2021, 61(11):5614-5625. doi: 10.1021/acs.jcim.1c00879. [百度学术]
Le XH, Lee CP, Millar AH. The mitochondrial pyruvate carrier (MPC) complex mediates one of three pyruvate-supplying pathways that sustain Arabidopsis respiratory metabolism[J]. Plant Cell, 2021, 33(8):2776-2793. doi: 10.1093/plcell/koab148. [百度学术]